Ion sources, systems and methods

The disclosure of the present application relates to ion sources, systems and methods.

For example, a liquid metal ion source or a gas electric field ion source can be used to form ions. In some cases, the ions formed by the ion source can be used to determine the specific properties of the sample to be irradiated with the ions or to modify the sample. In other cases, the ions formed by the ion source can be used to determine specific properties of the ion source itself.

<p> In one embodiment, the invention features a system comprising a gas electric field ion source capable of interacting with a gas to generate an ion beam having a spot size of 10 nm or less on the surface of a sample.</p><p> In another aspect, the invention features a system comprising an ion source capable of interacting with a gas to generate an ion beam having a spot size of 3 nm or less on the surface of the sample.</p><p> In a further embodiment, the invention interacts with a gas and is 1 × 10 on the surface of the sample.⁹A / cm²It features a system that includes a gaseous electric field ion source capable of generating an ion beam with a brightness greater than or equal to sr.</p><p> In an additional aspect, the invention interacts with a gas and is 5 × 10 on the surface of the sample.⁸A / cm²It features a system that includes a gas electric field ion source capable of generating an ion beam having a reduction brightness of srV or higher.</p><p> In one embodiment, the invention interacts with a gas and is 5 × 10.^-21cm²It features a system that includes a gaseous electric field ion source capable of generating an ion beam with etandue of sr or less.</p><p> In another embodiment, the invention interacts with a gas and is 1x10.^-16cm²It features a system that includes a gaseous electric field ion source capable of generating an ion beam with a reduced ethanedu of srV or less.</p><p> In a further aspect, the invention features a system comprising a gaseous electric field ion source with a conductive tip. The gas electric field ion source can interact with a gas to generate an ion beam for a week or more without removing the conductive tip from the system.</p><p> In an additional aspect, the invention features a system comprising a gas electric field ion source capable of interacting with a gas and generating an ion beam for a week or more with a total interruption time of 10 hours or less.</p><p> In one embodiment, the invention features an ion microscope capable of producing an image of a sample. The above sample is different from the ion microscope, and the image of the sample has a resolution of 3 nm or less.</p><p> In another aspect, the invention features a gas electric field ion microscope capable of producing an image of a sample. Unlike the ion microscope, the sample image has a resolution of 10 nm or less.</p><p> In a further aspect, the invention features a gas electric field ion microscope with a quality factor of 0.25 or greater.</p><p> In an additional aspect, the invention features an ion microscope with a damage test value of 25 nm or less.</p><p> In one embodiment, the present invention features an ion microscope comprising an ion source having a conductive tip with a terminal shelf having no more than 20 atoms.</p><p> In another aspect, the invention features a system comprising a gaseous electric field ion source with a conductive tip having an average perfect conical angle of 15 ° to 45 °.</p><p> In a further aspect, the invention features a system comprising a gaseous electric field ion source having a conductive tip with an average radius of curvature of 200 nm or less.</p><p> In an additional aspect, the invention features a system comprising a gaseous electric field ion source with a conductive tip comprising a terminal shelf having one or more atoms. In the above system, when using the system, one or more atoms interact with the gas to generate an ion beam, and 70% or more of the ions in the ion beam reaching the surface of the sample are the gas and one or more atoms. It is configured so that it can be generated by interacting with only one of the atoms.</p><p> In one embodiment, the invention features a system comprising a gas electric field ion source having a conductive tip capable of interacting with a gas to generate an ion beam. The system also includes an ion optics configured to allow at least a portion of the ion beam to pass through the ionic optics during use. In addition, the system includes a moving mechanism coupled to a gas electric field ion source, so that the moving mechanism can translate the conductive tip, tilt the conductive tip, or both.</p><p> In another aspect, the invention comprises a system comprising an ion source capable of interacting with a gas and interacting with a sample to generate an ion beam capable of emitting a plurality of different types of particles from the sample. It is a feature. The system also includes at least one detector configured to detect at least two different types of particles among a plurality of different types of particles. A plurality of different types of particles are selected from secondary electrons, Auger electrons, secondary ions, secondary neutral particles, primary neutral particles, scattered ions and photons.</p><p> In a further aspect, the invention features a system comprising a gas electric field ion source capable of interacting with a gas and generating an ion beam capable of interacting with and emitting particles from the sample. .. The particles are selected from Auger electrons, secondary ions, secondary neutral particles, primary neutral particles, scattered ions and photons. The system also includes at least one detector configured to allow at least one detector to detect at least some particles and determine information about the particles during use.</p><p> In an additional aspect, the invention features a system comprising a gas electric field ion source capable of interacting with a gas and generating an ion beam capable of interacting with and emitting particles from the sample. To do. The system also includes at least one detector configured to allow at least one detector to detect at least some particles during use. For a given detection particle, at least one detector produces a signal based on the energy of the given detection particle.</p><p> In one embodiment, the invention comprises a system comprising a gas electric field ion source capable of interacting with a gas and generating an ion beam capable of interacting with and emitting particles from the sample. .. The system also includes at least one detector configured to allow at least one detector to detect at least some particles during use. For a given detection particle, at least one detector produces a signal based on the orbital angle of the given detection particle.</p><p> In another aspect, the invention features a system comprising a gas electric field ion source capable of interacting with a gas and generating an ion beam capable of interacting with and emitting scattered ions from the sample. To do. The system also includes at least one detector configured to allow at least one detector to detect at least some scattered ions during use. In addition, the system includes an electronic processor that is electrically connected to at least one detector so that it can process information based on scattered ions detected by the electronic processor during use and determine information about the sample.</p><p> In a further aspect, the invention comprises a system comprising a gas electric field ion source capable of interacting with a gas and generating an ion beam capable of interacting with the sample to produce primary neutral particles from the sample. It is a feature. The system also includes at least one detector configured to allow at least one detector to detect at least some primary neutral particles during use. In addition, the system processes an electronic processor that is electrically connected to at least one detector so that it can process information based on the primary neutral particles detected by the electronic processor during use and determine information about the sample. Including.</p><p> In one embodiment, the invention comprises a system comprising a gas electric field ion source capable of interacting with a gas and generating an ion beam capable of interacting with and emitting photons from the sample. .. The system also includes at least one detector configured to allow at least one detector to detect at least some photons during use. In addition, the system includes an electronic processor that is electrically connected to at least one detector so that it can process photon-based information detected by the electronic processor during use and determine information about the sample.</p><p> In another aspect, the invention features a system comprising a gas electric field ion source capable of interacting with a gas and generating an ion beam capable of interacting with and emitting secondary ions from the sample. And. The system also includes at least one detector configured to allow at least one detector to detect at least some secondary ions during use. In addition, the system includes an electronic processor that is electrically connected to at least one detector so that it can process information based on secondary ions detected by the electronic processor during use and determine information about the sample. ..</p><p> In a further aspect, the invention comprises a gas electric field ion source capable of interacting with a gas and generating an ion beam capable of interacting with the sample to produce secondary neutral particles from the sample. It is characterized by. The system also includes at least one detector configured to allow at least one detector to detect at least some secondary neutral particles during use. In addition, the system is an electronic processor that is electrically connected to at least one detector so that it can process information based on secondary neutral particles detected by the electronic processor during use and determine information about the sample. including.</p><p> In an additional aspect, the invention features a system comprising a gas electric field ion source capable of interacting with a gas and generating an ion beam capable of interacting with and emitting Auger electrons from the sample. And. The system also includes at least one detector configured to allow at least one detector to detect at least some Auger electrons during use. In addition, the system includes an electronic processor that is electrically connected to at least one detector so that it can process information based on Auger electrons detected by the electronic processor during use and determine information about the sample.</p><p> In one embodiment, the invention comprises a system comprising a gas electric field ion source capable of interacting with a gas and generating an ion beam capable of interacting with and emitting ions from the sample. .. The system also includes at least one detector configured to allow at least one detector to detect ions during use. The interaction of the ion beam with the sample can emit secondary electrons from the sample, and when the interaction of the ion beam with the sample emits secondary electrons from the sample, at least one detector. However, at least some ions can be detected without detecting secondary electrons.</p><p> In another aspect, the invention features a system comprising a gas electric field ion source capable of interacting with a gas and generating an ion beam capable of interacting with the sample to emit neutral particles from the sample. And. The system also includes at least one detector configured to allow at least one detector to detect neutral particles during use. The interaction of the ion beam with the sample can emit secondary electrons from the sample, and when the interaction of the ion beam with the sample emits secondary electrons from the sample, at least one detector. However, at least some neutral particles can be detected without detecting secondary electrons.</p><p> In a further aspect, the invention features a system comprising a gas electric field ion source capable of interacting with a gas and generating an ion beam capable of interacting with and emitting photons from the sample. .. The system also includes at least one detector configured to allow at least one detector to detect photons during use. The interaction of the ion beam with the sample can emit secondary electrons from the sample, and when the interaction of the ion beam with the sample emits secondary electrons from the sample, at least one detector. However, at least some photons can be detected without detecting secondary electrons.</p><p> In one embodiment, the invention features a system comprising a gas electric field ion source capable of interacting with a gas to generate an ion beam having a spot size of 10 nm or less on the surface of a sample. The system also includes an ion optics configured to direct the ion beam toward the surface of the sample, the ionic optics having at least one adjustable setting. When the adjustable setting of the ion optics is in the first setting, the ion beam interacts with the first position of the sample. When the adjustable setting of the ion optics is in the second setting, the ion beam interacts with the second position of the sample. The first setting of the ion optical instrument is different from the second setting of the ion optical instrument, and the first position of the sample is different from the second position of the sample.</p><p> In another aspect, the invention features a system comprising a gas electric field ion source capable of interacting with a gas to generate an ion beam directed at a sample. The system also includes a charged particle source configured to allow the charged particle source to supply a beam of charged particles directed at the sample during use. The gas electric field ion source is different from the charged particle source.</p><p> In a further embodiment, the present invention causes an ion beam to interact with a sample to emit a plurality of different types of particles from the sample, and to detect at least two different types of particles among a plurality of different types of particles. It features methods that include doing. A plurality of different types of particles are selected from secondary electrons, Auger electrons, secondary ions, secondary neutral particles, primary neutral particles, scattered ions and photons.</p><p> In an additional aspect, the invention comprises a method comprising interacting a gas with a gas electric field ion source to generate an ion beam, and interacting the ion beam with a sample to eject particles from the sample. It is a feature. The particles are selected from Auger electrons, secondary ions, secondary neutral particles, primary neutral particles, scattered ions and photons. The method also includes detecting at least some particles and determining information about the sample.</p><p> In one embodiment, the invention features a method comprising interacting a gas with a gas electric field ion source to generate an ion beam, and interacting the ion beam with a sample to eject particles from the sample. And. The method also includes generating a signal from the detector based on the energy of the particles detected by the detector.</p><p> In another aspect, the invention features a method comprising interacting a gas with a gas electric field ion source to generate an ion beam, and interacting the ion beam with a sample to eject particles from the sample. And. The method also includes generating a signal from the detector based on the orbital angle of the particles detected by the detector.</p><p> In a further aspect, the invention comprises a method comprising interacting a gas with a gas electric field ion source to generate an ion beam and interacting the ion beam with a sample to produce scattered ions from the sample. It is a feature. The method also includes detecting at least some of the scattered ions and determining information about the sample based on the detected scattered ions.</p><p> In an additional aspect, the present invention comprises interacting a gas with a gas electric field ion source to generate an ion beam, and interacting the ion beam with a sample to produce primary neutral particles from the sample. It features a method that includes. The method also includes detecting at least some of the primary neutral particles and determining information about the sample based on the detected primary neutral particles.</p><p> In one embodiment, the present invention features a method comprising interacting a gas with a gas electric field ion source to generate an ion beam, and interacting the ion beam with a sample to emit photons from the sample. And. The method also includes detecting at least some photons and determining information about the sample based on the detected photons.</p><p> In another embodiment, the present invention comprises interacting a gas with a gas electric field ion source to generate an ion beam, and interacting the ion beam with a sample to produce secondary ions from the sample. It is characterized by. In addition, the above method includes detecting at least a part of secondary ions.</p><p> In a further embodiment, the present invention is to generate an ion beam by interacting a gas with a gas electric field ion source, and to interact with an ion beam i with a sample to produce secondary neutral particles from the sample. It features a method that includes. In addition, the above method includes detecting at least a part of secondary neutral particles or particles generated from the secondary neutral particles.</p><p> In an additional aspect, the invention comprises generating an ion beam by interacting a gas with a gas electric field ion source, and interacting the ion beam with a sample to emit Auger electrons from the sample. It is characterized by. The method also includes detecting at least some Auger electrons.</p><p> In one embodiment, the present invention comprises forming a gas electric field ion source, and after forming the gas electric field ion source, arranging the ion source indoors to prepare a gas electric field ion system. It is a feature.</p><p> In another embodiment, an ion source having an emission axis is formed, and after forming the ion source, the emission axis of the ion source is aligned with the inlet axis of the ion optical system.</p><p> In a further embodiment, the present invention generates an ion beam by interacting a gas with a gas electric field ion source, and the ion beam has a spot size of 10 nm or less on the surface of a sample. And a method of moving an ion beam from a first position on the surface of a sample to a second position on the surface of the sample, the first position being different from the second position.</p><p> In an additional aspect, the invention features a method comprising interacting a gas with a gas electric field ion source to generate an ion beam and contacting a sample with the ion beam. The method also includes contacting the sample with a beam of charged particles from a charged particle source.</p><p> In one embodiment, the invention features a method comprising interacting a gas with a gas electric field ion source to generate an ion beam, and interacting the ion beam with a sample to eject particles from the sample. And. The method also includes detecting at least some particles and determining crystal information about the sample based on the detected particles.</p><p> In another aspect, the invention features a method comprising interacting a gas with a gas electric field ion source to generate an ion beam and inducing a voltage on some samples. The method also includes detecting particles and determining voltage contrast information for the sample.</p><p> In a further aspect, the invention features a method comprising interacting a gas with a gas electric field ion source to generate an ion beam, and interacting the ion beam with a sample to eject particles from the sample. And. The sample contains at least the first substance and the second substance. The method also includes distinguishing between the first and second substances based on the particles.</p><p> In an additional aspect, the invention generates an ion beam by interacting a gas with a gas field ion source, and interacts the ion beam with an activated gas to cause a chemical reaction on the surface of a sample. It features methods that include facilitating.</p><p> In one embodiment, the invention comprises a method comprising interacting a gas with a gas electric field ion source to generate an ion beam and using the ion beam to determine information on an inner layer surface of a semiconductor product. It is a feature. The method also includes editing the semiconductor product based on the information on the inner layer surface.</p><p> In another aspect, the invention features a method comprising interacting a gas with a gas electric field ion source to generate an ion beam, and using the ion beam to determine information about a semiconductor product. .. The ion beam has a spot size of 10 nm or less on the surface of a semiconductor product. In addition, the above method includes editing a semiconductor product based on information.</p><p> In a further aspect, the invention comprises a method comprising interacting a gas with a gas electric field ion source to generate an ion beam and using the ion beam to determine information about a lithography mask. .. The ion beam has a spot size of 10 nm or less on the surface of a semiconductor product. The method also includes repairing the lithographic mask informedly.</p><p> In an additional aspect, the invention features a method comprising patterning a resist on a sample using an ion beam. The ion beam has a spot size of 10 nm or less on the sample.</p><p> In one embodiment, the present invention features a method comprising interacting a gas with a gas electric field ion source to generate an ion beam, and interacting the ion beam with a sample containing a feature. The ion beam has a spot size of 50 nm or less on the surface of the sample. In addition, the above method includes determining the size of the feature portion.</p><p> In another aspect, the invention features a method comprising interacting a gas with a gas electric field ion source to generate an ion beam, and interacting the ion beam with a sample to eject particles from the sample. And. The sample has a plurality of stacked layers including a first layer and a second layer. The method also includes detecting the particles and determining if the second layer is combined with the first layer.</p><p> In a further aspect, the invention features a method comprising irradiating a sample with a focused ion beam and generating a second ion beam by interacting a gas with a gas electric field ion source. The method also includes irradiating the sample with a second ion beam.</p><p> In an additional aspect, the invention features a method comprising forming a conductive tip of a gas electric field ion source when it is present in an ion microscope.</p><p> In one embodiment, the invention features a system that includes an ion source. The system is capable of imaging the ion source in the first mode, and the system is capable of collecting images of the sample in the second mode using the ion source. The sample is different from the ion source.</p><p> In another aspect, the invention comprises a housing, a disc supported by the housing, and a member supported by the disc that has legs and a surface configured to support the sample. It features a sample manipulator that includes an instrument. The device is in contact with the member in the first mode to move the sample, and the device is not in contact with the member in the second mode.</p><p> In an additional aspect, the invention features a system that includes a gas electric field ion source and a sample manipulator. The sample manipulator includes a housing, a disc supported by the housing, a member supported by the disc and having legs and a surface configured to support the sample, and an apparatus. .. The device is in contact with the member in the first mode to move the sample, and the device is not in contact with the member in the second mode.</p><p> In one embodiment, the present invention generates a first beam containing ions by interacting a gas with a gas field ion source, and removes non-monovalent chemical species from the first beam to generate monovalent ions. It features a method comprising forming a second beam containing.</p><p> In an additional aspect, the invention features a system comprising a gas electric field ion source capable of interacting with a gas to generate a beam containing a species containing a charged species. The system also includes at least one bias electrode configured to branch the beam path of the species in the beam based on the charge of the species.</p><p> In another aspect, the invention features a method comprising interacting a gas with a gas electric field ion source to generate ions and sputtering a sample with the ions.</p><p> In a further aspect, the invention features a method comprising interacting a gas with a gas electric field ion source to generate an ion beam and generating an electron beam using a system different from the gas electric field ion source. And. The method also includes investigating the sample using both an ion beam and an electron beam.</p><p> In another aspect, the invention features a system that includes a scanning electron microscope capable of supplying an electron beam. The system also includes a gaseous electric field ion source capable of interacting with the gas to generate an ion beam. Scanning electron microscopes and gaseous field ion microscopes are positioned so that samples can be investigated using both electron and ion beams during use.</p><p> In an additional aspect, the invention features a method comprising interacting a gas with a gas electric field ion source to generate a first ion beam. The first ion beam has a first current. In addition, the above method includes preparing a gas electric field ion source for investigating a sample by using a first ion beam having a first current. Further, the method includes generating a second ion beam by interacting the gas with a gas electric field ion source. The second ion beam has a second current. In addition, the method comprises investigating the sample using a second ion beam.</p>

<p> The embodiment can include one or more of the advantages shown below.</p><p> In some embodiments, the ion source (eg, a gaseous electric field ion source) can provide a relatively small spot size on the surface of the sample. An ion microscope using such an ion source (for example, a gas electric field ion microscope) can obtain an image of a sample with relatively high resolution, for example.</p><p> In certain embodiments, the ion source (eg, a gaseous electric field ion source) can have relatively high brightness and / or relatively high reduction brightness. An ion microscope using such an ion source (for example, a gas field ion microscope) can take an image of a high quality sample in a relatively short time, for example, which in turn images a large number of samples. The speed can be increased so that it can be done.</p><p> In some embodiments, the ion source (eg, a gaseous electric field ion source) can have a relatively high brightness due to a given ion current (eg, a relatively low etandu). An ion microscope using such an ion source (for example, a gas electric field ion microscope) can take an image of a high quality sample with relatively small damage to the sample, for example.</p><p> In certain embodiments, the gas electric field ion microscope can have relatively high reliability. Thus, for example, a gas field ion source can be used for a long period of time without exchanging the gas field ion source, which can, for example, increase the speed so that a large number of samples can be imaged, or a large number. The downtime associated with sample imaging and / or the costs associated with imaging a large number of samples can be reduced.</p><p> In some embodiments, an ion microscope (eg, a gas electric field ion microscope) is configured such that vibrations are substantially separated from the ion source. This can improve the ability of the ion microscope to achieve one or more of the above advantages.</p><p> In certain embodiments, an ion microscope (eg, a gas electric field ion microscope) can operate at relatively high temperatures while providing one or more of the advantages described above. For example, liquid nitrogen can be used as a cooling agent for an ion microscope. This can reduce the costs and / or complexity associated with the use of other specific coolants such as liquid helium. This can also reduce potential problems associated with certain mechanical systems used with liquid helium coolants that can cause significant vibration.</p><p> Other features and advantages of the present invention will become apparent from the specification, drawings and claims.</p>

The same kind of reference symbols in various drawings indicate the same kind of elements.

<u style="single">Outline introduction</u> In a microscope system, ions can be created and used for sample imaging and other uses. A microscope system that uses a gas field ion source to generate ions that can be used for sample analysis (eg, imaging) is called a gas field ion microscope. The gas electric field ion source applies a high positive potential (eg, 1 kV or more compared to the extraction section (see below)) to the top of the conductive tip while applying a neutral gas species near the conductive tip (eg, for example). A top with a conductive tip (generally 10 or less atoms) that ionizes a neutral gas species to generate ions (eg, in the form of an ion beam) by bringing it within a distance of about 4-5 Å. Is a device including).

FIG. 1 shows a gas electric field via a gas source 110, a gas electric field ion source 120, an ion optical device 130, a sample manipulator 140, a front detector 150, a back detector 160, and communication lines 172a to 172f. A conceptual diagram of a gas electric field microscope system 100 including various elements of the ion microscope system 100 and an electronic control system 170 (for example, an electronic processing device such as a computer) electrically connected to the ion microscope system 100 is shown. Sample 180 is located within / above the sample manipulator 140 between the ion optics 130 and the detectors 150, 160. In use, the ion beam 192 is directed at the surface 181 of the sample 180 through the ion optical instrument 130, and the particles 194 produced by the interaction of the ion beam 192 with the sample 180 are measured by the detector 150 and / or 160.

In general, it is preferred to exhaust the system 100 to reduce the presence of certain undesired chemical species in the system. In general, the different elements of the system 100 are maintained at different background pressures. For example, about 10^-10The gas electric field ion source 120 can be maintained at the pressure of Torr. When introducing a gas into the gas electric field ion source 120, the background pressure is about 10^-5Ascend to Torr. The ion optics 130 is about 10 prior to the introduction of the gas into the gas electric field ion source 120.^-8Maintained at Torr background pressure. When introducing a gas, the background pressure in the ion optics 130 is generally about 10.^-7Increase to Torr. Sample 180 is generally about 10^-6Located in a room maintained by Torr background pressure. This pressure changes little with the presence or absence of gas in the gas electric field ion source 120.

As shown in FIG. 2, the gas source 110 is configured to supply one or more types of gas 182 to the gas electric field ion source 120. As described in detail below, the gas source 110 can be configured to supply one or more gases of varying purity, flow rate, pressure and temperature. Generally, at least one of the gases supplied by the gas source 110 is a noble gas (helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe)), and the ion of the rare gas. Is preferably the main component in the ion beam 192. Generally, when measured on the surface 181 of the sample 180, the pressure of the noble gas in the system 100 increases, so that the current of the ions in the ion beam 192 increases monotonically. In certain embodiments, this relationship can be explained by the exponential law that for a range of noble gas pressures, the current generally increases in proportion to the gas pressure. During work, the noble gas pressure is generally 10 near the top of the tip (see description below).^-2Below Torr (eg 10^-3Below Torr, 10^-4Torr and below) and / or 10^-7Torr or higher (eg 10^-6Torr and above, 10^-5Torr and above). In general, it is preferable to use a relatively pure gas (eg, to reduce the presence of unwanted chemical species in the system). When He is used as an example, He can be at least 99.99% pure (eg, 99.995% pure, 99.999% pure, 99.9995% pure, 99.9999% pure). Similarly, when other noble gases are used (Ne gas, Ar gas, Kr gas, Xe gas), the purity of the gas is preferably high purity commercial grade.

The gas source 110 can optionally supply one or more gases in addition to one or more rare gases. As will be described in detail below, an example of such a gas is nitrogen. In general, one or more additional gases can be present at levels above the level of impurities in the one or more rare gases, but one or more additional gases are still introduced by the gas source 110. Consists of a minority component of the entire gas mixture to be produced. As an example, in an embodiment in which He gas and Ne gas are introduced into a gas electric field ion source by a gas source 110, the total gas mixture is Ne 20% or less (for example, 15% or less, 12% or less) and / or Ne 1% or more. (For example, 3% or more, 8% or more) can be included. For example, in an embodiment in which He gas and Ne gas are introduced by the gas source 110, the gas mixture can contain Ne 5% to 15% (for example, 8% to 12%, 9% to 11%) as a whole. As another example, in the embodiment in which He gas and nitrogen gas are introduced by the gas source 100, the gas mixture as a whole has nitrogen of 1% or less (for example, 0.5% or less, 0.1% or less) and / or nitrogen of 0.01% or more (for example). , 0.05% or more) can be included. For example, in the embodiment in which the He gas and the nitrogen gas are introduced by the gas source 110, the gas mixture has a total nitrogen of 0.01% to 1% (for example, 0.05% to 0.5%, 0.08 to 0. 12%) can be included. In some embodiments, one or more additions (eg, by the use of a gas manifold that mixes the gas and then delivers the mixture to the system 100 through a single inlet) before entering the system 100. The gas is mixed with one or more noble gases. In certain embodiments, one or more additional gases are not mixed with one or more noble gases prior to entry into system 100 (eg, a separate inlet is for injecting each gas into system 100). However, their separate inlets are close enough to allow the gas to mix before interacting with any element in the gas field ion source 120).

The gas electric field ion source 120 is configured to receive one or more types of gas 182 from the gas source 110 and generate gas ions from one or more types of gas 182. The gas electric field ion source 120 includes a conductive tip 186 having a tip top 187, an extraction section 190, and optionally a suppressor. Generally, the distance from the top of the tip 187 to the surface 181 of the sample 180 (not shown in FIG. 2) is 5 cm or more (eg, 10 cm or more, 15 cm or more, 20 cm or more, 25 cm or more) and / or 100 cm or less (for example, 80 cm). Below, 60 cm or less, 50 cm or less). For example, in some embodiments, the distance from the top of the tip 187 to the surface 181 of the sample 180 is 5 cm to 100 cm (eg, 25 cm to 75 cm, 40 cm to 60 cm, 45 cm to 55 cm).

The conductive tip 186 can be formed of various substances. In some embodiments, the tip 186 is a metal (eg, tungsten (W), tantalum (Ta), iridium (Ir), rhenium (Rh), niobium (Nb), platinum (Pt), molybdenum (Mo)). Is formed by. In certain embodiments, the conductive tip 186 can be made of an alloy. In some embodiments, the conductive tip 186 can be made of a different material (eg, carbon (C)).

In use, the tip 186 is positively biased with respect to the extraction section (eg, about 20kV) and the extraction section 190 is negatively or positively biased with respect to the external grounding section (eg, -20kV to + 50kV). The suppressor 188 is positively or negatively biased with respect to the tip 186 (eg, -5kV to + 5kV). Since the tip 186 is formed of a conductive material, the electric field of the tip 186 at the tip top 187 faces outward from the surface of the tip top 187. Due to the shape of the tip 186, its electric field is strongest near the tip top 187. The strength of the electric field at the tip 186 can be adjusted, for example, by changing the positive voltage applied to the tip 186. In this configuration, the unionized gas atom 182 supplied by the gas source 110 is ionized into positively charged ions in the vicinity of the tip apex 187. The positively charged ions are simultaneously ejected by the positively charged tip 186 and attracted by the negatively charged extraction unit 190 so that the positively charged ions as the ion beam 192 are directed from the tip 186 into the ion optical device 130. Be done. The suppressor 188 helps control the entire electric field between the tip 186 and the extraction unit 190, and as a result, helps control the trajectory of the positively charged ions from the tip 186 to the ion optics 130. In general, the entire electric field between the tip 186 and the extraction unit 190 is controlled by controlling the rate at which positively charged ions are produced at the tip top 187 and the efficiency with which the positively charged ions are transferred from the tip 186 to the ion optical device 130. Can be adjusted.

I do not want to be bound by theory, but as an example, it seems that He ions can be created as follows. The gas electric field ion source 120 is configured so that the electric field of the tip 186 in the vicinity of the tip top 187 exceeds the ionized electric field of the unionized He gas atom 182, and the tip 186 is maintained at a relatively low temperature. When the unionized He gas atom 182 is close to the tip top 187, the tip electric field can polarize the He atom, creating a weak attractive force between the He atom 182 and the tip top 187. As a result, the He atom 182 can come into contact with the top of the tip and remain bonded (for example, physically adsorbed) for a while. The electric field in the vicinity of the tip top 187 is high enough to ionize the He atom 182 adsorbed on the tip top 187, generating positively charged He ions (eg, in the form of an ion beam).

FIG. 3 is a schematic representation of the tip apex 187 (the tip apex is formed by W (111), see description below). Tip 187 includes layers of atoms arranged to form an atomic shelf. The terminal atom shelf is formed by atoms 142. The second atomic shelf is made up of 144 atoms and the third atomic shelf is made up of 146 atoms. The neutral gas atom 182 delivered by the gas source 110 exists in the vicinity of the tip top 187. Atom 182 is polarized by the electric field at the top of the tip 187 and undergoes a relatively weak attraction that directs the atom 182 towards the top of the tip 187, as indicated by the arrow on the top 182.

Depending on the strength of the electric field at the tip, each atom in the atom shelf close to the tip top 187 can have a corresponding ionization disk 148. The ionization disk 148 is a spatial region in which a neutral He atom enters the ionization disk 148 and is likely to be ionized. In general, the ionization of a neutral He atom is caused by an electron passing from the neutral He atom to the atom at the top of the tip. Therefore, the ionization disk 148 indicates a spatial region in which He ions are generated and He ions escape.

The size of the ionized disk 148 for a particular tip top atom is determined by the shape of the tip top 187 and the potential applied to the tip top 187. In general, ionization of a He atom can occur in a spatial region near the top of the tip 187, where the local electric field exceeds the ionization potential of the He atom. Therefore, due to the large potential applied to the tip apex 187, a large number of tip atoms will have an ionized disc. In addition, the local electric field in the vicinity of the tip top 187 is determined by the shape of the tip top 187. At the relatively sharp tip apex, the local electric field near the tip apex 187 is relatively high. At the relatively blunt tip apex, the local electric field is small even in the vicinity of the tip apex 187.

In FIG. 3, the ionized disks 148 corresponding to the individual atoms at the top of the tip 187 are spatially separated from each other. In some embodiments, if the electric field at the tip apex 187 is large enough, ionized disks from more than one atom (eg, atom 142) can spatially overlap, resulting in multiple tip apex atoms. It forms a large ionized disk that spans adjacent spatial areas. By reducing the electric field at the tip top 187, the volume of space occupied by the ionized disk 148 can be reduced and the shape shown in FIG. 3 can be realized, where each of the few tip top atoms Has a unique ionized disk that is spatially separated. In many cases, the shape of the tip top 187 is not easily changed when the ion source 120 is used, so that the electric field in the vicinity of the tip top 187 is generally controlled by adjusting the potential applied to the tip top 187.

Further, by reducing the potential applied to the tip top 187, a part of the ionized disk shown in FIG. 3 can be removed. For example, the tip apex 187 is not sharp in the vicinity of atom 144 on the second atomic shelf, and by reducing the potential applied to the tip apex 187, the electric field of the tip apex 187 in the vicinity of the atom 144 can be reduced. Since it can be done, there is a high possibility that the ionization of He atoms will not occur in those regions. As a result, the ionized disc corresponding to atom 144 no longer exists. However, the electric field at the tip top 187 in the vicinity of atom 142 on the end shelf can remain high enough to result in ionization of He atoms, so the ionization disk 148 corresponding to atom 142 remains. By carefully controlling the potential applied to the top of the tip 187, only the ionized disks corresponding to the atoms 142 on the end shelf exist, and the ionized disks corresponding to the atoms on the end shelf are spatially separated from each other. , The ion source 120 can operate. As a result, He atoms, which are ionized in the vicinity of the tip apex 187, are created by ionization in the vicinity of specific end shelf atoms.

The longer the neutral He atom 182 stays in the ionization disk 148, the more likely it is to be ionized. The polarization of the He atom is induced by the electric field of the tip apex 187 and moves the polarized He atom toward the tip apex 187, further ensuring that the polarized He atom remains bound to the tip apex 187. , He increases the time that He atoms 182 remain in the ionization disk 148, increasing the possibility of ionization of polarized He atoms over time.

Also, the polarized He atom can move from one position to the other along the surface of the tip apex 187. Since the attractive force between the polarized He atom and the tip top 187 is determined by the local strength of the electric field of the tip top 187 at the position of the polarized He atom, the movement of the polarized He atom is determined by the tip top 187 of the tip 186 with the highest local electric field. There is a tendency to transfer the atom towards the edge of (eg, towards the end shelf 142). This polarized He atom transfer mechanism, in combination with the control of the potential applied to the tip 186 (eg, to ensure that there is a separate ionizing disk corresponding only to the atom 142 on the end shelf), He The ion beam 192 can be used to operate the ion source 120 as it is produced by the gas field ion source 120. Here, the individual He ions in the ion beam are generated by the interaction between the He gas and one of the terminal shelf atoms 142. Thus, the ion beam 192 contains a plurality of He ions from each terminal shelf atom 142, and each He ion can be attributed to ionization from one of the terminal shelf atoms 142.

As described above, in general, the size and shape of the ionized disc can be changed by changing the potential applied to the tip top 187, and the adjacent ionized discs 148 are overlapped by the appropriately applied potential. It is possible to maintain a state in which they are spatially separated from each other by an appropriately small applied potential. Generally, the ionized disc 148 is spaced about 0.4 nm from the tip atoms 142, 144 and 146. The individual ionized discs corresponding to the tip atoms generally have a thickness of about 0.02 nm as measured along the line connecting the given disc and the corresponding atoms. The ionized disk 148 generally has a diameter as large as the diameter of the corresponding atom, as measured in a direction perpendicular to the line connecting the predetermined disk and the corresponding atom.

FIG. 4 shows the working configuration of the tip apex 187, where the potential applied to the tip 186 creates three ionized disks 148, each corresponding to one of the three terminal atom shelves atoms 142. When He ions are created near the tip apex 187, they are rapidly accelerated away from the tip by a large positive tip potential. He ions are accelerated along multiple orbits and move away from the tip apex 187. Two such orbits 156 are shown in FIG. As shown in FIG. 4, the orbital 156 corresponds to the right and left limits of the full width at half maximum (FWHM) of the orbital distribution for the central atom of the terminal shelf. When orbitals 156 are thus estimated backwards (eg, along line 154) towards the location of the central end shelf atom, they define a virtual source 154 for the central end shelf atom. The diameter of the virtual source 152 is generally smaller than the diameter of the central terminal shelf atom and may be significantly smaller than the diameter of the central terminal shelf atom (for example, 2 times or more, 3 times or more, 5 times or more, 10 times or more). Similar considerations apply to other end shelf atoms, where each end shelf atom has a corresponding virtual source size.

The small size of the virtual source for end-shelf atoms can provide many advantages. For example, the small size of the virtual source of the ion beam 192 and the small thickness of the ionization disk in which the ions are generated in the ion beam 192 mean that the ion beam 192 has a relatively high brightness and a relatively narrow ion energy distribution. Can help ensure that.

We do not want to be bound by theory, but using a tip temperature that is too low can adversely affect current stability and / or increase the undesired effect from increased impurity adsorption on the tip. It seems that there are cases. Generally, the temperature of the tip 186 is 5K or higher (eg, 10K or higher, 25K or higher, 50K or higher, 75K or higher) and / or 100K or lower (eg, 90K or lower, 80K or lower). For example, the temperature of the tip 186 can be 5K to 100K (for example, 25K to 90K, 50K to 90K, 75K to 80K). For example, the temperature of the tip 186 can be achieved by thermal coupling with a coolant such as liquid helium or liquid nitrogen. Alternatively or additionally, a cryogenic cooler can be used to thermally cool the tip 186.

If the temperature of the tip 186 is too low, the rate of transfer of the adsorbed He atoms is reduced by moving them to the atom 142 of the terminal atom shelf of the tip top 187, so that the He atoms ionize them in an insufficient amount per unit time. It seems that it will arrive at the atom 142 that can. As a result, when observing the emission pattern of the tip 186 (eg, using field ion microscopy (FIM) technology or scanning FIM (SFIM) technology), the abundance of ions from the individual end shelf atoms is relatively high. It goes back and forth from abundance to relatively low abundance (usually called blanking). This can happen, for example, when there is no He atom available for ionization in the vicinity of the terminal shelf atom at some time. As the temperature of the tip 186 rises, the transfer rate of He atoms towards the end shelves of the atoms at the tip top 187 increases, and such alternating high / low abundances from the end shelf atoms 142 are observed. Reduce or eliminate.

Also, if the temperature of the tip 186 is too high, the polarized He atom will have too much kinetic energy, which is long enough to ensure efficient ionization of the He atom in the vicinity of the terminal shelf atom 142. Cannot keep the state of being bound to. Moreover, this may result in the disappearance of emission patterns from individual end shelf atoms when observed using FIM imaging techniques and / or SFIM imaging techniques. As a result, in order to ensure that the He ionization treatment at each end shelf atom 142 produces a stable ion current from each end shelf atom 142, the temperature of the tip 186 should be carefully controlled, resulting in undesired high temperature effects and It is to mitigate both low temperature effects.

Generally, the ion optical instrument 130 is configured to direct the ion beam 192 toward the surface 181 of the sample 180. As will be described in detail below, the ion optical device 130 can, for example, focus, parallelize, accelerate and / or decelerate the ions in the ion beam 192. Further, the ion optical device 130 enables only a part of the ions in the ion beam 192 to pass through the ion optical device 130. Generally, the ion optics 130 includes various electrostatic ionic optics and other ionic optics configured as desired. By manipulating the electric field strength of one or more components (eg, electrostatic deflectors) in the ion optics 130, the He ion beam 192 can be scanned over the surface 181 of the sample 180. For example, the ion optical instrument 130 can include two deflectors that deflect the ion beam 192 in two orthogonal directions. The deflector can have varying electric field intensities, resulting in rasterization of the ion beam 192 over a region of 181 surfaces.

When the ion beam 192 collides with the sample 180, it can produce a variety of different types of particles 194. These particles include, for example, secondary electrons, Auger electrons, secondary ions, secondary neutral particles, primary neutral particles, scattered ions and photons (eg, X-ray photons, IR photons, visible photons, UV photons). .. The detectors 150 and 160 are configured so that they can each measure one or more different types of particles that interact between the He ion beam 192 and the sample 180. As shown in FIG. 1, the detector 150 is located primarily to detect particles 194 emanating from the surface 181 of the sample 180, and the detector 160 is predominantly located to detect particles 194 emanating from the surface 183 of the sample 180 (eg, for example. , Transmitted particles) are located to detect. As will be described in detail below, in the microscope system generally disclosed in the present application, any number and configuration of detectors can be used. In some embodiments, a plurality of detectors are used, some of which are configured to measure different types of particles. In certain embodiments, the detector is configured to provide different information about the same type of particle (eg, particle energy, angular distribution of a given particle, total abundance of a given particle). Optionally, such detector arrangements can be used in combination.

In general, the information measured by the detector is used to determine information about sample 180. Illustrative information about sample 180 includes topography information about surface 181, material composition information (on the inner layer surface of surface 181 and / or sample 180), crystal orientation information of sample 180, and voltage contrast information about surface 181. (And the resulting electrical properties), voltage contrast information about the inner layer surface of the sample 180, the optical properties of the sample 180, and / or the magnetic properties of the sample 180. Generally, this information is determined by obtaining one or more images of sample 180. By rasterizing the ion beam 192 over the surface 181 it is possible to obtain pixel-by-pixel information about the sample 180 in discontinuous steps. The detectors 150 and / or 160 can be configured to detect one or more different types of particles 194 at each pixel. Generally, the pixels are square, but in some embodiments, the pixels can have different shapes (eg, rectangles). The pixel size corresponds to the length of the side of the pixel, and can be, for example, 100 pm to 2 μm (for example, 1 nm to 1 μm). In some embodiments, the position of adjacent pixels can be determined within at least 200 pm (eg, at least 100 pm, at least 75 pm, at least 50 pm). Therefore, the operator of the system can determine the position of the center of the beam spot within at least 200 pm (eg, at least 100 pm, at least 75 pm, at least 50 pm). In certain embodiments, the field of view (FOV) of sample 180 is 200 nm or more (eg, 500 nm or more, 1 μm or more, 50 μm or more, 100 μm or more, 500 μm or more, 1 mm or more, 1.5 mm or more) and / or 25 mm or less (15 mm or less, 10 mm or less, 5 mm or less). The field of view refers to the area of the sample surface imaged by an ion microscope.

The operation of the microscope system 100 is generally controlled by the electronic control system 170. For example, one or more kinds of gases supplied by the gas source 110, the temperature of the tip 186, the potential of the tip 186, the potential of the extraction unit 190, the potential of the suppressor 188, the setting of the elements of the ion optical instrument 130, the sample manipulator 140. The electronic control system 170 can be configured to control the position and / or the position and settings of the detectors 150 and 160. Optionally, one or more of these parameters may be manually controlled (eg, by a user interface integrated with the electronic control system 170). Additional or instead, using an electronic control system 170 (eg, by an electronic processing device such as a computer), the information collected by the detectors 150 and 160 is analyzed and information about the sample 180 (eg, topography information, etc.). Material composition information, crystal information, voltage contrast information, optical characteristic information, magnetic information) can be provided, and the information can be arbitrarily in the form of an image, a graph, a table, a table calculation, or the like. In general, the electronic control system 170 may include a display or other type of output device, input device, and user interface featuring a recording medium.

<u style="single">Helium ion microscope system</u>A. Overview FIG. 5 shows a schematic view of the He ion microscope system 200. The microscope system 200 includes a first vacuum housing 202 surrounding the He ion source and the ion optics 130, and a second vacuum housing 202 surrounding the sample 180 and the detectors 150, 160. The gas source 110 delivers He gas to the microscope system 200 through the delivery tube 228. The flow rate regulator 230 controls the flow rate of the He gas passing through the delivery pipe 228, and the temperature controller 232 controls the temperature of the He gas in the gas source 110. The He ion source includes a tip 186 attached to the tip manipulator 208. The He ion source also includes an extraction unit 190 and a suppressor 188 configured to induce He ions from the tip 186 into the ion optical instrument 130. The ion optical device 130 includes a first lens 216, an alignment deflectors 220 and 222, an aperture 224, an astigmatism corrector 218, a scanning deflectors 219 and 221 and a second lens 226. The diaphragm 224 is located at the diaphragm mounting portion 234. The sample 180 is mounted in / on the sample manipulator 140 in the second vacuum housing 204. Further, detectors 150 and 160 are located in the second vacuum housing 204, and are configured to detect particles 194 from the sample 180. Gas source 110, tip manipulator 208, extraction unit 190, suppressor 188, first lens 216, alignment deflector 220 and 222, aperture mounting unit 234, astigmatism corrector 218, scanning deflector 219 and 221, sample manipulator 140 And / or the detectors 150 and / or 160 are generally controlled by the electronic control system 170. Optionally, the electronic control system 170 is configured to control the vacuum pumps 236 and 237, which are configured to provide a decompression environment inside the vacuum housings 202 and 204 and inside the ion optics. To.

B. Ion source As mentioned above, the tip 186 can generally be formed of any suitable conductive material. In certain embodiments, the tip 186 can be formed of a single crystal material such as a single crystal metal. In general, the orientation of a particular single crystal on the terminal shelf of the atom at the tip top 187 is within 3 ° of the longitudinal axis of the tip 186 (eg, within 2 °, within 1 °). Align the axes. In some embodiments, the top 187 of the tip 186 has a fixed number of atoms (eg, 20 or less atoms, 15 or less atoms, 10 or less atoms, 9 or less atoms, 6 or less atoms). , 3 or less atoms) can be terminated in an atomic shelf. For example, the top 187 of the tip 186 can be formed by W (111) and can have a terminal shelf with three atoms (trimers). 6 and 7 show a schematic enlarged top view and a schematic enlarged side view of the two atomic shelves of the W tip 186 closest to the tip top, respectively. The terminal shelf contains three W atoms 302 arranged in a trimer and corresponds to the (111) surface of W. We do not want to be bound by theory, but because the surface energy of the W (111) crystal plane is arranged in an equilateral triangle and favorably supports the end shelf formed by the three W atoms forming the trimer. , This trimer appears to be advantageous (in terms of ease of formation, reformation and stability). The trimer atom 302 is supported by the second shelf of the W atom 304.

In some embodiments, the tip 186 can have a terminal shelf containing less than three atoms or more than three atoms. For example, the W (111) tip may have an end shelf containing two atoms, or it may have an end shelf containing only one atom. Alternatively, the tip of W (111) has 4 or more atoms (for example, 5 or more atoms, 6 or more atoms, 7 or more atoms, 8 or more atoms, 9 or more atoms, 10 or more atoms). It can also have an end shelf containing (atoms of, more than 10 atoms).

Alternatively or additionally, tips corresponding to other W crystal orientations (eg, W (112), W (110) or W (100)) can be used, such as one or more tips. Atoms (eg, 2 or more atoms, 3 or more atoms, 4 or more atoms, 5 or more atoms, 6 or more atoms, 7 or more atoms, 8 or more atoms, 9 or more atoms It can have an end shelf containing atoms, 10 or more atoms, more than 10 atoms).

In some embodiments, a tip formed of a substance other than the single crystal W can be used as the ion source (eg, a single crystal of a metal, such as a single crystal of one of the above metals). The tip is 1 or more atoms (for example, 2 or more atoms, 3 or more atoms, 4 or more atoms, 5 or more atoms, 6 or more atoms, 7 or more atoms, 8 or more atoms It can have an end shelf containing atoms, 9 or more atoms, 10 or more atoms, more than 10 atoms).

As described below, the shape of the tip apex 187 can affect the quality of the ion beam, which can affect the performance of the microscope system 200. For example, when viewed from the side, the tip apex 187 may be formed symmetrically with respect to its longitudinal axis, or the tip apex 187 may be formed asymmetrically with respect to its longitudinal axis. In certain embodiments, the tip apex 187 may be formed symmetrically about its longitudinal axis when viewed from one or more sides, or the tip apex 187 may be formed symmetrically about its longitudinal axis from one or more different side views. It may be formed asymmetrically with respect to the axis. FIG. 8 shows a side view of an exemplary tip 300 formed asymmetrically with respect to its longitudinal axis 308 (at a very small magnification compared to FIGS. 6 and 7). From a predetermined side view, the degree to which the tip 300 is asymmetrically formed along the longitudinal axis 308 can be quantified using parameters such as, for example, the average perfect cone angle and the average cone direction. These parameters are determined as follows.

Images of the tip 300 are obtained using a scanning electron microscope (SEM). FIG. 8 is a schematic diagram of such an image. Tip 300 includes apex 310 and a second point 312, both located on longitudinal axis 308, with point 312 located along longitudinal axis 308 1 μm from apex 310. The imaginary line 314 extends perpendicular to the axis 308 through point 312 in the plane of FIG. Line 314 intersects the contour of tip 300 at points 316 and 318. Left cone angle θ_lIs the angle between the tangent at point 316 of the contour of the tip 300 and line 320 (the imaginary line that extends through point 316 and parallel to axis 308). Similarly, the right cone angle θ_rIs the angle between the tangent at point 318 of the contour of the tip 300 and line 322 (an imaginary line that extends through point 318 and parallel to axis 308). The perfect conical angle of the tip 300 is θ_lAnd θ_rIs the total size of. For example, θ_lThe size of is 21.3 ° and θ_rIn a given side view of an embodiment having a size of 11.6 °, the perfect conical angle of the contour of the tip 300 for that side view is 32.9 °. Since the tip 300 can appear symmetrical in one side view and asymmetric in different side views, it is usually preferable to determine the average perfect conical angle of the tip 300. The average perfect cone angle measures the perfect cone angle for eight different side views of the tip 300 (each corresponding to a continuous rotation of the tip 300 at 45 ° around axis 308 with respect to the tip side view of the tip 300. ), Then it is determined by calculating the average of the eight perfect cone angles thus determined, resulting in the average perfect cone angle. We do not want to be bound by theory, but if the average perfect cone angle is too small, an arc discharge may occur when using the tip (for example, when creating an ion beam 192 with the tip 300), and It is considered that the generation of He ions due to the interaction between He atoms on the terminal shelf at the tip and other tip atoms may be caused by a large electric field in the vicinity of the tip 300. In addition, if the average perfect cone angle is too large, the ability to reconstruct the tip 300 with good reproducibility may decrease, and the electric field near the tip 300 is too low to reliably ionize He atoms, resulting in stable He. It seems that it may not be possible to generate an ion current. In some embodiments, the average perfect conical angle of the tip 300 can be 45 ° or less (eg, 42 ° or less, 40 ° or less, 35 ° or less, 32 ° or less, 31 ° or less), and / Alternatively, the average perfect cone angle can be 15 ° or more (for example, 20 ° or more, 23 ° or more, 25 ° or more, 28 ° or more, 29 ° or more). For example, the average perfect conical angle of the tip 300 can be 27 ° to 33 ° (eg, 28 ° to 32 °, 29 ° to 31 °, 30 °). In certain embodiments, the standard deviation for the eight perfect cone angle measurements is 40% or less of the average perfect cone angle (eg, 30% or less, 20% or less, 10% or less).

The conical direction is θ_lAnd θ_rIt is half the absolute value of the difference in magnitude of. Therefore, for example, θ_lThe size of is 21.3 ° and θ_rIn a given side view of an embodiment in which the magnitude of is 11.6 °, the conical direction is 0.5 * | 21.3 ° -11.6 ° |, i.e. 4.9 °. For the same reasons as described above for the average perfect cone angle, it may be preferable to determine the average cone direction of the tip. The average conical orientation measures the conical orientation of eight different side views of the tip 300 (each corresponding to a continuous rotation of the tip 300 at 45 ° around axis 308 with respect to the previous side view), and then eight average cones. Determined by calculating the average of the orientation measurements, it yields an average conical direction. In some embodiments, the average conical direction of the tip 300 can be 10 ° or less (eg, 9 ° or less, 8 ° or less, 7 ° or less, 6 ° or less, 5 ° or less) and / or The average conical direction of the tip 300 can be 0 ° or more (for example, 1 ° or more, 2 ° or more, 3 ° or more, 4 ° or more). In certain embodiments, the average conical direction of the tip 300 is 0 ° to 10 ° (eg, 1 ° to 10 °, 3 ° to 10 °, 6 ° to 10 °, 2 ° to 8 °, 4 ° to 6). °).

Further, the tip 300 can be characterized by its radius of curvature, and the radius of curvature can be determined as follows. FIG. 9 shows a schematic side view of the tip 300. In practice, this side view is obtained using SEM. Measure the slope of the contour of the tip 300 on both sides of the longitudinal axis 308. Points 324 and 326 are shown on the surface of the tip 300 closest to the top 310, and the slope of the contour of the tip 300 (indicated by tangents 328 and 330, respectively) has values of 1 and -1 respectively (eg,). 45 ° slope line). The distance between the point 324 measured perpendicular to the axis 308 and the axis 308 on the plane of FIG. 9 is the left tangential distance T of the tip 300._lIs. The distance between the point 326 and the axis 308 measured perpendicular to the axis 308 on the plane of FIG. 9 is the right tangential distance T of the tip 300._rIs. Left radius R_lIs<img file="JP2009517841A_D0001.tif" />Calculated as the right radius R_rIs<img file="JP2009517841A_D0002.tif" />Is calculated as. The radius of curvature R of the tip 300 is R_lAnd R_rIs calculated as the average of. So, for example, T_lIs 120 nm, T_rIn embodiments where is 43 nm, R_lIs 169 nm, R_rIs 61 nm and R is 115 nm. For the same reasons as described above for the average perfect cone angle and the average cone direction, it may be preferable to determine the average radius of curvature of the tip. The mean radius of curvature measures the radius of curvature for eight different side views of the tip 300 (each corresponding to a continuous rotation of the tip 300 at 45 ° around axis 308 with respect to the previous side view), then eight curvatures. Determined by calculating the average radius, it yields the average radius of curvature. We do not want to be bound by theory, but if the average radius of curvature is too small, arc discharge may occur when using the tip and / or the ionization of He gas on the terminal atom shelf of the tip is at the other tip. It seems that it may occur near the atom. If the average radius of curvature is too large, the ability to reconstruct the tip with good reproducibility may decrease, and the ionization rate of He atoms near the tip 300 may decrease due to the decrease in the electric field strength near the tip 300. In some embodiments, the mean radius of curvature of the tip 300 is 200 nm or less (eg, 180 nm or less, 170 nm or less, 160 nm or less, 150 nm or less, 140 nm or less, 130 nm or less) and / or the mean radius of curvature of the tip 300. Is 40 nm or more (for example, 50 nm or more, 60 nm or more, 70 nm or more, 80 nm or more, 90 nm or more, 100 nm or more, 110 nm or more). For example, in some embodiments, the tip 300 has an average radius of curvature of 40 nm to 200 nm (eg, 50 nm to 190 nm, 60 nm to 180 nm, 70 nm to 170 nm, 80 nm to 160 nm). In certain embodiments, the standard deviation of the eight radius of curvature measurements is 40% or less of its average radius of curvature (eg, 30% or less, 20% or less, 10% or less).

FIG. 10 is a flow chart of the process 400 for producing a W (111) tip having a trimer terminal atom shelf. In the first step 402, the precursor wire of the single crystal W (111) is attached to the support assembly. In general, the W (111) precursor wire has a diameter of 3 mm or less (eg, 2 mm or less, 1 mm or less) and / or 0.2 m or more (eg, 0.3 mm or more, 0.5 mm or more). In some embodiments, the W (111) precursor wire has a diameter of 0.2 mm to 0.5 mm (eg, 0.3 mm to 0.4 mm, 0.25 mm). Suitable precursor wires can be obtained, for example, from FEI Beam Technology, Inc. (Hills Baro, OR).

In some embodiments, more generally, the tip precursor can be in a different form than the wire. For example, it is possible to form a precursor for the tip of a conductive substance having protrusions to be terminated in a crystal structure. The ends of the protrusions can be, for example, a single crystal structure, formed of W (111), or formed of another material having a similar or different crystal orientation.

11A and 11B show a perspective view and a bottom view of one embodiment of the support assembly 520, respectively. The support assembly 520 includes support columns 522a and 522b connected to the support base 524. Pillars 522a and 522b are connected to heating lines 526a and 526b, and a single W (111) precursor wire 528 is connected to heating lines 526a and 526b (eg, by welding). Pillars 522a and 522b can be connected to auxiliary devices such as, for example, a power source (eg, power supply), allowing temperature control of the W (111) precursor wire 528.

The base 524 provides mechanical support for the assembly 520 and is usually formed of one or more materials that can withstand temperature cycles and act as electrical insulators. For example, in some embodiments, the substrate 524 is formed from an electrical insulator such as glass and / or a hard polymer and / or ceramic.

Pillars 522a and 522b are usually made of one or more conductive materials. In general, the material used to form the columns 522a and 522b can have similar coefficients of thermal expansion between the columns 522a and 522b and the base 524, with the columns 522a and 522b having the base 524 during the temperature cycle of the precursor wire 528. It is chosen to remain fixed in place with respect to. In some embodiments, columns 522a and 522b are formed from an alloy containing iron, nickel and cobalt. An example of a commercially available material capable of forming columns 522a and 522b is KOVAR.^TMIs.

The heating wires 526a and 526b are generally formed from one or more substances having higher electrical resistance compared to the precursor wire 528. For example, in some embodiments, heating wires 526a and 526b can be formed from a material such as a tungsten-rhenium alloy. As described below, the heating wires 526a and 526b generate heat as current flows through the wire (eg, from an external power supply) and use that heat to precursor during various advanced treatment steps. The temperature of body line 528 can be increased and / or controlled. Generally, the diameters and materials of the heating wires 526a and 526b are selected so that proper control of the temperature of the precursor wire 528 can be achieved during the manufacturing process. In some embodiments, the heating lines 526a and 526b have a diameter of, for example, 100 μm to 750 μm.

The geometric properties of the base 524, columns 522a and 522b and the heating lines 526a and 526b can usually be selected as desired. For example, in some embodiments, the distance between columns 522a and 522b can be 1 mm to 10 mm.

Optionally, more than two columns (eg, three columns, four columns, five columns, six columns) can be attached to the base 524, with each column precursor through the corresponding heating wire. It is connected to body line 528. Providing additional columns can increase the stability of the assembly 520 and / or reduce the sensitivity of the assembly 520 to mechanical vibrations.

In some embodiments, a support assembly that applies compressive force to the precursor wire 528 can hold the precursor wire 528 in place. For example, FIG. 12 shows an exemplary support assembly 550 including a Bogel attachment for fixing the precursor wire 528. Suitable Bogel mounts are commercially available, for example, from AP Tech (McMinnville, OR). The support assembly 550 includes a support base 556 and a mounting arm 552 attached to the base 556. To secure the precursor wire 528, the arm 552 is pried open and a spacer 554 (eg, formed of pyrolytic carbon) is inserted in the gap between the arms. Next, the precursor wire 528 is inserted into the opening between the spacers 554. Due to the elasticity of the arm 552, the arm exerts a compressive force on the spacer 554 and the precursor wire 528 in the directions indicated by the arrows 558 and 560, thereby fixing the precursor wire 528 to the spacer 554. .. The coefficient of static friction between the wire 528, the spacer 528 and the arm 552 suppresses the relative movement of those members and ensures that the wire 528 remains fixed in place in the support assembly 550. Generally, the line 528 extends above the arm 552 at a distance of, for example, 1 mm to 5 mm.

The base 556 can be formed from materials similar to those that can be used to form the base 524 (eg, glass and / or hard polymers and / or ceramics). The material of the base 556 is generally an electrical insulator that can withstand a temperature cycle.

The mounting arm 552 can be formed from one or more conductive materials. Further, as for the substance used for forming the arm portion 552, the base portion 556 and the arm portion 552 have the same coefficient of thermal expansion, and the arm portion 552 is in an appropriate position with respect to the base portion 556 during the temperature cycle of the precursor wire 528. Selected to remain fixed. In some embodiments, the arm 552 is formed from an alloy containing iron, nickel and cobalt. KOVAR is a commercially available material suitable for forming the arm 552.^TMCan be mentioned.

The spacer 554 is formed from a substance such as pyrolytic carbon. Suitable pyrolytic carbon spacers are available, for example, from AP Tech (McMinnville, OR). Pyrolytic carbon spacers are generally formed of a series of carbon slabs that are layered on top of each other to form a layered structure. In general, the resistivity of pyrolytic carbon varies with direction, and the resistivity of carbon in the direction perpendicular to the plate (eg, in the direction approximately perpendicular to the surface of the laminated plate) is in the direction of the surface parallel to the surface of the plate. Higher than the resistivity along. At the time of attachment, the spacer 554 is oriented so that the direction of the high resistivity of the spacer 554 is substantially parallel to the direction of the compressive force applied to the arm 552 (eg, substantially parallel to the arrows 558 and 560). When an electric current is applied to the arm 552, the spacer 554 generates heat due to its high resistivity. Therefore, the spacer 554 can function as a heating element for adjusting the temperature of the precursor wire 528.

Again, referring to FIG. 10, in step 404, the precursor wire 528 is etched in the electrochemical tank and the tip of the wire 528 is shaped. In general, step 404 includes a plurality of substeps.

The first sub-step in the etching process can optionally be a cleaning step for removing surface contaminants from the wire 528. This etching process involves arranging the wire 528 in the electrochemical etching solution and applying an alternating current (AC) voltage to the wire 528. For example, the etching solution can be a 1N sodium hydroxide (NaOH) solution, and an AC voltage of 1V can be used. The entire support assembly (eg, support assembly 520 or 550) can then be cleaned (eg, ultrasonic cleaning in water) to remove certain residual contaminants.

The next sub-step in step 404 is to optionally apply a resist material to a portion of wire 528. Generally, the resist material is applied from the top of the wire 528 to cover a length of about 0.5 mm of the wire 528. The application of the resist material can be achieved, for example, by dropping a small amount of the resist solution on a clean surface or by immersing the line 528 in the resist several times while drying the resist between applications. The applied resist limits the amount of precursor wire 528 that is etched during subsequent processing steps. By using a resist material, a large number of tips are formed on a given precursor wire before discarding the precursor wire, as the formation of a subsequent tip on the precursor wire 528 often follows the removal of the tip by etching. Allows you to. A wide variety of resist materials can be applied to the precursor wire 528. An exemplary resist material is a cosmetic nail brightener. In some embodiments, one or more resist materials can be used. The use of the resist material is optional for the tip forming process, and in some embodiments, the precursor wire 528 may not be coated with the resist material during the manufacturing process and a subsequent process may be initiated.

The next sub-step of step 404 is to electrochemically etch the precursor wire 528. Various electrochemical etching means can be used. In some embodiments, the electrochemical etching means shown below is used. The support assembly is installed on an etching fixture that includes a support assembly, a dish, and a translation device for translating the electrodes (eg, stainless electrodes) that extend over the dish. Place the etching solution on the dish so that the etching solution comes into contact with the electrodes. The translation device lowers the support assembly towards the dish until the resist contact surface of wire 528 is just in contact with the etchant. The wire 528 is then reduced by an additional amount (eg 0.2 mm) in the etchant.

The etchant contains components that chemically corrode wire 528 (eg, NaOH). In the embodiment in which the etching solution contains NaOH, the concentration of NaOH in the etching solution can be selected to change the corrosion rate of the precursor wire 528 and the chemical environment of the solution. For example, in some embodiments, the concentration of NaOH is 0.1 M or higher (eg, 0.2 M or higher, 0.5 M or higher, 0.6 M or higher, 0.8 M or higher, 1.2 M or higher, 1.4 M or higher, 1.6 M or higher, 2.0. M or more, 2.5M or more, 3.0M or more) and / or 10.0M or less (for example, 9.0M or less, 8.0M or less, 7.0M or less, 6.5M or less, 6.0M or less, 5.5M or less, 5.0M or less, 4.5M Below, it can be 4.0M or less). In some embodiments, the NaOH concentration is 0.5M to 10.0M (eg, 1.0M to 9.0M, 1.5M to 8.0M, 2.0M to 7.0M, 2.0M to 6.0M, 2.0M to 3.0M). Is.

In certain embodiments, other corrosives can be added to the etchant in place of or in addition to NaOH. Examples of such corrosives are KOH (including molten KOH), HCl, H.₃PO₄, H₂SO₄, KCN and / or molten NaNO₃Can be mentioned. The corrosive agent in the etchant can be selected based on its ability to corrode precursor wires formed of a particular type of substance. For example, a reagent such as NaOH can be used to corrode the wire formed by W. Other corrosive agents can be used in the etching solution for wires formed of different substances such as Ir.

In some embodiments, the etchant can contain a relatively small amount of surfactant. Without wishing to be bound by theory, it seems that surfactants can help facilitate the symmetric etching of precursor wire 528. Surfactants suitable for such purposes include materials such as PhotoFlo 200 available from Eastman Kodak (Rochester, NY). Generally, the concentration of the surfactant in the etching solution is 0.1% by volume or more (for example, 0.2% by volume or more, 0.3% by volume or more, 0.4% by volume or more) and / or 2% by volume or less (for example, 1% by volume or less, 0.8% by volume or less, 0.6% by volume or less).

Further, in some embodiments, the etching process can be performed while stirring the etching solution. The stirring speed of the etching solution can be empirically determined based on the result of the etching process.

After installing the precursor wire 528 in the etching solution, an external power supply is connected to both the wire 528 and the electrode, and an electric potential is applied over the wire 528 and the electrode to cause an electrochemical corrosion reaction of the wire 528. Can be facilitated. Generally, a voltage can be applied from either an AC source or a direct current (DC) source. Generally, the amplitude of the applied voltage can be selected as desired, based on empirical determination of the amplitude that produces the uniformly etched precursor wire 528. For example, in some embodiments, the amplitude of the applied potential is 3.0 V or higher (eg, 3.2 V or higher, 3.5 V or higher, 4.0 V or higher, 5.0 V or higher, 10 V or higher, 15 V or higher, 20 V or higher) and / or It is 50V or less (for example, 40V or less, 35V or less, 30V or less, 25V or less). In some embodiments, the amplitude of the applied potential is 3.0V to 50V (eg, 3.5V to 40V, 4.0V to 30V, 4.5V to 20V).

The duration of the AC pulse applied to the etchant can usually be varied as desired to facilitate controlled etching of line 528. For example, in some embodiments, the pulse applied to the etchant is 10 ms or longer (eg, 25 ms or higher, 50 ms or higher, 75 ms or higher, 100 ms or higher, 150 ms or higher, 200 ms or higher, 250 ms or longer) and / or 1 second. It has a duration of 900 ms or less, 800 ms or less, 700 ms or less, 650 ms or less, 600 ms or less). In some embodiments, the pulse applied to the etchant has a duration of 10 ms to 1 second (eg, 10 ms to 900 ms, 10 ms to 800 ms, 10 ms to 700 ms, 10 ms to 600 ms).

In general, pulses that vary in duration and / or amplitude can be applied to the etchant to result in corrosion of the precursor wire 528 in the region of the line in contact with the solution. Generally, during the treatment, a part of the end of the precursor wire 528 falls off in the etching solution, and a newly exposed and etched region of the precursor wire 528 is further treated in a subsequent step. For example, a suitable etching formulation would include an initial application of about 100 AC pulses with an amplitude of 5 V, each pulse having a duration of about 580 ms. Then a series of about 60 pulses is applied, each pulse having a duration of about 325 ms and an amplitude of 5 V. A pulse with a duration of 35 ms and an amplitude of 5 V is then applied until part of the end of wire 528 falls off into the etchant.

The immersion depth of the precursor wire 528 can be adjusted while the electric pulse is applied to the etching solution. In general, the etching process results in the formation of small diameter regions in the precursor wire 528. Adjusting the immersion depth of wire 528 can help ensure that the meniscus of the etchant is aligned near the midpoint of the small diameter region, forming a relatively symmetrical tip. Can increase the possibility of etching. When approaching the drop-off point (eg, when the diameter of the small diameter region becomes very small), adjust the immersion depth to ensure that the end of the precursor wire 528 does not snap. After the end of the precursor wire 528 has fallen off, the tip of the newly exposed wire 528 is very slightly immersed in the etching solution and an additional electrical pulse is applied. In some embodiments, two electrical pulses are applied. As an example, the first pulse can be 1V to 10V (eg, 3V to 7V, 5V) with a duration of 20ms to 50ms (eg, 30ms to 40ms, 35ms) and the second pulse can be from 10ms to 25ms (eg, 30ms to 25ms). , 15ms ~ 20ms, 17ms) and can be 1V ~ 10V (eg 3V ~ 7V, 5V).

The support assembly is then removed from the etching fixture, rinsed (eg with distilled or deionized water) and dried (eg under dry nitrogen gas).

The next step 406 of process 400 is to examine the support assembly (particularly the etched tip of wire 528) to ensure that the etched tip has a suitable feature. As mentioned earlier, for example, determining the feature involves obtaining an image of the contour of the etched tip and calculating various geometric parameters from the data obtained from the contour image. For example, SEM can be used for inspection. The contour image of the tip of line 528 can be obtained at a very high magnification, for example, at a magnification of 65,000 ×. Geometric parameters to be measured include, for example, the average radius of curvature of the tip, the average conical direction and the average perfect conical angle. Here, if the shape of the etched tip is inappropriate, return it to the etching fixture, insert the assembly, and lower the tip toward the dish until the etched tip of wire 528 just contacts the etching solution. Therefore, it may be possible to reshape the tip a little. The tip of wire 528 can be reshaped using a small number of electrical pulses (eg, 1-3 pulses with a duration of 35 ms and an amplitude of 5 V). For example, if the average perfect cone angle of the tip of line 528 is too small, a small number of short duration pulses can be used to increase the average perfect cone angle without substantially increasing the average radius of the etched tip. .. Following the application of such additional electrical pulses, the SEM can be re-examined at the tip to ensure that the tip has been properly reshaped.

Next, in step 408, a terminal shelf at the top of the tip of the etched wire 528 is formed into a trimer. This process usually involves imaging the tip (eg, using FIM or SFIM) and shaping the tip (eg, using field evaporation).

In some embodiments, step 408 includes installing a support assembly on the FIM and evacuating the FIM. Cool the tip of wire 528 (eg to liquid nitrogen temperature) and bring He gas to FIM (eg about 5x10)^-6Supply (at Torr pressure). When a positive potential (for example, 5 kV or more with respect to the extraction part) is applied to the tip of the line 528 with respect to the extraction part, the He atom interacts with the tip top of the line 528 to form a He ion. Accelerate the He ion and move it away from the top of the tip of the positively charged wire 528. A detector such as a fluorescent screen, which is arbitrarily connected to a two-dimensional image device such as a CCD camera, is located at a distance selected from the ion source and is oriented substantially perpendicular to the trajectory of the main ion beam from the ion source. Has been done. Collision ions emit photons on a fluorescent screen, which is detected by a CCD camera. The image region corresponding to a relatively large number of detected ions looks brighter than the image region corresponding to a relatively small number of detected ions. Ionization of He gas atoms occurs at the top of the tip of line 528 in the vicinity of individual source atoms. As a result, the image captured by the detector corresponds to the emission pattern of the ion source. In particular, the bright spots in the image obtained from the detector correspond to the individual atoms at the top of the ion source. Therefore, the FIM image is an image of the top of the tip of line 528, which is atomically decomposed. Based on the FIM image, the crystal structure, orientation and specific arrangement of atoms at the top of the ion source can be determined.

If the top of the tip of wire 528 does not have the desired properties, the tip can be shaped, for example, using field evaporation. During electric field evaporation, the resulting electric field is the local electric field, with the image of the etched tip of line 528 still in focus on the FIM detector and the background pressure of the He gas still present in the FIM. Increase the positive potential of the tip until you start removing W atoms (and contaminating atoms) from the highest tip position (eg, 15 kV or more relative to the extractor). Controls the rate at which atoms are removed and prevents groups of atoms from being removed at the same time. In general, field evaporation is continued while monitoring the FIM emission pattern until the surface of the etched tip is confirmed to be in proper crystal orientation to determine the absence of unwanted contaminants on the tip shelf.

It may be preferable to polish the tip after field evaporation. To polish the tip, He gas is sent out of the FIM chamber, and as a result of changing the bias of the tip of the wire 528 to negative with respect to the common ground, the top of the tip of the wire 528 emits electrons. A detector such as a glass screen coated with a phosphor that receives incident electrons and generates photons is positioned so as to catch electrons from the tip. The generated photons are detected by a suitable detector (eg, a CCD device, a photomultiplier tube, a photon diode or another type of photon detector) and are used to monitor the emission of electrons from the tip. In some embodiments, the detector can be linked directly to the photon generator. In certain embodiments, the detector and photon generator are not directly connected. For example, an optical element such as a mirror can be used to direct the generated photons at the detector.

Adjust the voltage bias applied to the tip until the desired electron current is measured (eg, 25pA to 75pA, 40pA to 60pA, 50pA). The tip is then heated to the desired temperature (eg 1000K-1700K, 1300K-1600K, 1500K) and the tip is visually monitored to emit light emitted from the tip under both voltage and heat application. To detect. The emission of light from the tip is such that the light emitted by the tip is reflected, for example, towards a suitable photon detector (eg, a CCD device, a photomultiplier tube, a photon diode or another type of photon detector). It can be monitored using a mirror placed in. Heat can be applied to the tip using various devices such as resistance heating devices (eg, filament heaters), radiant heating devices, induction heating devices or electron beams. 15 to 45 seconds (for example, 25 to 35 seconds, 30 seconds) after the first appearance of light from the tip, both the applied potential and the heating device are stopped, and a trimer is provided as the terminal atom shelf. Get line 528.

Optionally, a gas can be used to polish the tip. For example, oxygen can be introduced into the FIM chamber to promote polishing of the round W tip surface. After removing He from the FIM chamber, a polishing gas (eg, oxygen) is introduced and the tip is heated at a selected pressure for a period of time in the presence of oxygen. For example, to polish a round W tip, first He is sent out of the FIM chamber and then the tip is heated to a temperature of 1300K to 1700K (eg 1500K). The tip is maintained at 1500K for 1-5 minutes. Next, while maintaining the temperature of the tip for about 2 minutes, about 10^-5Oxygen can be introduced into the chamber by the pressure of Torr. The oxygen flow to the chamber is continued, then the temperature of the tip is lowered to 700K to 1200K (eg 1000K) and the tip is maintained at that temperature for about 2 minutes. Finally, the oxygen supply to the above chamber is closed and the oxygen pressure here is 10.^-7Oxygen is pumped out of the room until it is less than Torr. At the same time, the tip is cooled to normal operating temperature (eg, about 77K in some embodiments) and He is reintroduced into the FIM chamber. When the tip is imaged in FIM mode, a W trimer is observed on the tip corresponding to the W (111) facet. The W (111) wire with the trimer end shelf can then be removed from the FIM and stored for future use.

An embodiment of imaging / shaping the top of the line using a FIM separated from the system 200 is described above, but in some embodiments the system 200 can be used as the FIM. In such an embodiment, a support assembly is installed inside the ion source and the system 200 is typically operated as a FIM according to the procedure described in the previous paragraph. In some embodiments, when operating the system 200 in FIM mode, the detector can be located where the sample 280 is normally located (ie, the sample 180 is not in the normal position). In certain embodiments, when the system 200 is operated in FIM mode, a flat sample with relatively high secondary electron emissions can be located where sample 180 is normally located and is detected. Since the intensity of secondary electrons generally corresponds to the intensity of He ions incident on a flat sample, secondary electrons generated by the interaction between He ions and a flat sample are detected.

Optionally, the system 200 can be operated in SFIM mode during the process of imaging / shaping the top of the line tip. In such an embodiment, the process is described above, except that the alignment deflectors 220 and 222 are used to rasterize the ion beam over the surface of the diaphragm 224 to generate a field emission pattern at the top of the tip of the line. It is described in the paragraph. A portion of the ion beam passing through aperture 224 is optionally focused or remains unfocused by the second lens. In the SFIM mode, an image of the tip of the line is obtained for each pixel, and each pixel intensity measured corresponds to a part of ion beams that can pass through the aperture 224. Pixel intensities can be used together to represent a field emission pattern at the tip as an image or, more generally, as multiple electrical signals. Next, the field emission pattern can be used to evaluate various properties of the tip to determine suitability for use in a gas field ion microscope. In SFIM mode, you can install the types of detectors described in the previous paragraph. Optionally, the detector can be a spatially integrated detector such as a photomultiplier tube or a photodiode.

Usually, the procedure described above can be used to polish the W tip for the first time, or it can be used to repolish the W tip in an ion microscopy system. Such re-polishing can be performed even if the first process of polishing the W tip is performed by a FIM other than System 200. Generally, the re-polishing may be performed by the same method as the first polishing, or the re-polishing technique may be different from the first polishing technique. In some embodiments, the microscope system 200 can be configured to operate in FIM and / or SFIM modes as described above to assess whether regrinding is desirable. Based on the image of one or more tips, the repolishing process can be started or postponed. In certain embodiments, other criteria can be used to determine when to initiate regrinding. For example, if the measured ion current from the tip falls below a threshold set after the operating period, regrinding can be initiated.

As the first step of regrinding, the tip can be electrovaporated by electric field to remove atoms near the top of the tip. For example, the microscope system 200 can be configured to operate in FIM and SFIM modes as described above, carefully adjusting the potential applied to the tip to create controlled field evaporation of the tip atom. Can be done. During the field emission process, in FIM or SFIM mode, by a detector (eg, a photon detector coated with a phosphor or a secondary electron detector configured to measure secondary electron emission from a flat sample). A field emission image of the tip is obtained, and the field emission image can be monitored to determine when to stop the field emission process. As already mentioned, if the surface of the tip has a proper crystal orientation and is clean, the tip can be re-polished.

He gas has a He background pressure of about 10^-7It is pumped out of the microscope system 200 until it is less than Torr. In some embodiments, a negative potential is applied to the tip to initiate regrinding, the microscope system 200 is operated in electronic mode, and the tip is polished through heating as described above. In a particular embodiment, as described above, a polishing gas such as oxygen is introduced into the microscope system 200 and the tip is heated in the presence of oxygen for a selection time. Following the re-polishing procedure, the He gas was reintroduced into the microscope system 200 and captured one or more images of the re-polished tip with the system configured to operate in FIM and / or SFIM modes. , Confirm that the apex of the tip contains a trimer corresponding to the W (111) facet.

In some embodiments, the hardware and / or software of the electronic control system 170 can automatically perform a particular regrinding step. For example, in certain embodiments, the polishing procedure applied to the rounded tip can be performed in an automated manner. An example of a polishing algorithm executed by the electronic control system 170 is as follows. Initially, the control system 170 evacuates the microscope system 200 by driving pumps 236 and / or 237, cooling the tip to liquid nitrogen temperature. When the background pressure of the gas in the microscope system 200 is below a set threshold, the control system 170 heats the tip to a temperature of 1500 K by applying a calibration current to the heating line supporting the tip. After 2 minutes at 1500K, the control system 170 introduces oxygen gas into the microscope system 200 by opening the valve of the oxygen gas source. Adjust the valve opening, about 10 within the microscope system 200^-5Maintain the oxygen pressure of Torr. After another 2 minutes, the control system 170 regulates the flow of liquid nitrogen coolant into the system to reduce the tip temperature to 1100K. After 2 minutes at 1100K, control system 170 shuts off oxygen supply to the system and cools the tip to liquid nitrogen temperature. Here, the presence of W (111) at the top of the tip can be manually confirmed using FIM and / or SFIM images of the tip (measured by the operator).

Although not bound by theory, it seems that oxygen can promote the formation of trimers as a terminal atom shelf at the tip. In certain embodiments, the pressure of oxygen gas in the FIM chamber is 10^-7Torr or higher (eg 10^-6Torr and above, 10^-5Torr and above, 10^-4Torr or higher) and / or 1 Torr or lower (eg 10)^-1Below Torr, 10^-2Below Torr, 10^-3It can be Torr or less). In certain embodiments, the pressure of oxygen gas in the FIM chamber is 10^-8Torr ~ 10^-2Torr (eg 10^-7Torr ~ 10^-3Torr, 10^-6Torr ~ 10^-4It can be Torr). In addition, other gases and substances can be used to promote the formation of trimers as terminal atom shelves while polishing the tips. For example, a substance such as palladium, platinum, gold and / or iridium can be deposited on the surface of the rounded tip prior to regrinding. These materials appear to be able to promote the formation of more reliable trimers on the apex of the tip.

In some embodiments, polishing of the W tip can be achieved by controlling the tip heating without the application of an electric field or the planned addition of oxygen. For example, the W tip is polished by 1) installing the tip in the FIM chamber, 2) depressurizing the FIM chamber, and 3) heating the tip to 1000K for 5 minutes and cooling it (for example, to the temperature of liquid nitrogen). can do. Although not bound by theory, it seems that trace amounts of oxygen present as oxides on the tip can help polish the tip by heating. In certain embodiments, the unpolished tip can be exposed to an oxygen stream, placed in a substantially oxygen-free environment, and polished by controlled heating. This approach can create an oxide of W on the surface of the tip, and it seems that the oxygen released from the oxide of W during heating can be useful for the polishing process of the tip.

In some embodiments, one or more additional gases may be present during tip polishing. For example, in certain embodiments, nitrogen gas can be present. Although not bound by theory, it seems that nitrogen gas helps etch the tip and can provide a more rounded structure when the terminal atom shelf is a trimer, which is rounded. It seems to be more stable than the tip with no end treatment of the trimer. Generally, nitrogen gas is introduced at the same time as oxygen gas. In certain embodiments, the pressure of nitrogen gas in the FIM chamber is 10.^-8Torr or higher (eg 10^-7Torr and above) and / or 10^-5Below Torr (eg 10^-6It can be Torr). In certain embodiments, the pressure of nitrogen gas in the FIM chamber is 10.^-5Torr ~ 10^-8Torr (eg 10^-6Torr ~ 10^-7It can be Torr).

Optionally, a positive potential applied to the polished tip so that controlled electric field evaporation of the tip occurs to help ensure that the tip polishing process is repeatable after forming the trimer. To increase. After the tip is electric-evaporated for a period of time, the top of the tip takes a round shape again. In general, the rounded tip produces an emission pattern similar to the emission pattern of the tip after the first field evaporation step. The rounded tip is then re-polished in electronic mode to create a trimer-terminated atomic shelf (eg, by the procedure described above). In some embodiments, one or more trimers can be removed from the polished tip using field evaporation techniques to increase the life and stability of the polished tip. For example, the atomic layer at the top of the polished tip formed by the shelf of three atoms is removed to show the lower part of the atomic shelf containing more than three atoms. The newly exposed atomic shelves can be further electric field evaporated to create a W atom trimer at the top. This newly formed trimer can evaporate with additional trimers formed during electric field evaporation. This process leads to rounding the tip layer by layer in the vicinity of the top of the tip. By rounding the tip, the electric field gradient near the top of the tip is reduced, the atoms at the tip are less likely to undergo electric field evaporation while the microscope system 200 is operating, and the stability and lifetime of the tip are increased.

In step 410 of process 400, the top 187 of the tip 186 is aligned within the system 200. With the support assembly installed in the microscope system 200, one or more vacuum pumps are used to exhaust the microscope system 200 and then heat the tip 187 to, for example, oxides, condensates and / or tips. Removes other impurities that may adhere to the surface. Generally, for example, the tip 186 is heated to a temperature of 900 K or more (for example, 1000 K or more, 1100 K or more) and maintained for 10 s or more (for example, 30 s or more, 60 s or more). The heating may contact when the shape of the tip can be damaged by the presence of impurities you are, can help to put again face the tip 186.

By observing the light emitted from the tip 186 as a result of applying heat and then propagating along the longitudinal axis of the ion optical device 130 (for example, inserting a reflecting element such as a mirror). Then, by directing a part of the light to a detector such as a CCD camera), the tip is roughly aligned with the longitudinal axis of the ion optical device 130. By adjusting the tip manipulator 208 and directing the light from the tip 186 through the ion optics 130, the position and / or orientation of the tip 186 can be changed.

Following this rough alignment procedure, the background pressure in the vacuum housings 202 and 204 is reduced, the tip 186 is cooled (eg, to near liquid nitrogen temperature), and the gas source 110 brings it into the vicinity of the tip 186. The microscope system 200 is configured to operate in FIM or SFIM mode by introducing a He gas ion stream. An image of the field emission pattern of He ions from the tip 186 was measured by a properly configured detector, and based on this image, the tip manipulator 208 was used to determine the field emission pattern of the ion optical instrument 130 in the longitudinal axis and axis. By matching, the field emission pattern of the tip 186 is centered on the longitudinal axis. The center position can be tested by changing the potential applied to the first lens 216 while observing the induced modulation of the field emission pattern of the tip 186. If the magnitude of the field emission pattern observed by the detector changes with the change in potential applied to the lens 216, but the position of the center of the pattern does not change, then the tip 186 is the longitudinal axis of the first lens 216. Align with. Conversely, if the center position of the field emission pattern of the tip 186 changes in response to a change in potential applied to the first lens 216, then the tip 186 is not centered on the longitudinal axis of the first lens 216. The alignment and position adjustment of the tip 186 by the tip manipulator 208 can be repeated and repeated until the tip 186 is sufficiently aligned with the longitudinal axis of the first lens 216. Generally, if the aperture 224 is not in the proper position, this center position test is performed.

Fine alignment means can then be performed to ensure that the He ions generated by the interaction of the He gas atoms with the shelves of the three atoms at the top 187 of the tip 186 pass through the aperture 224. By adjusting the potential applied to the deflectors 220 and 222 (see description below), the squeeze 224 is squeezed by the interaction of the He gas atom with only one of the three trimer atoms at the top of the tip 186. 70% or more (for example, 75% or more, 80% or more, 85% or more, 90% or more, 95% or more, 97% or more, 99% or more) of He ions in the passing ion beam 192 are generated. At the same time, the adjustment of the potential applied to the deflectors 220 and 222 is such that the throttle 224 is 50% of the He ions in the ion beam 192 generated by the interaction of the He gas atom with the other two trimer atoms. Ensure that the above (eg, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, 98% or more) prevent reaching the surface 181 of sample 180. As a result of this fine alignment means, the He ion beam passing through the aperture 224 and exiting the ion optics 130 is the first He atom to be ionized in the vicinity of only one of the three trimeric atoms at the top of the tip 186. Including.

Seeing FIG. 10 again, in step 412 of process 400, the tip 186 is aligned with the longitudinal axis of the first lens 216, and the He ion beam is placed so that part of the ion beam 192 passes through the aperture 224. With the axes aligned, the microscope system 200 can be operated in He ion mode. In embodiments where the system 200 is used in FIM mode during tip polishing, the FIM detector and / or FIM components are moved so that the sample 180 can be placed for irradiation with the ion beam 192. A positive potential is applied to the tip 186 with respect to the extraction unit 190, and the He gas is introduced into the vacuum housing 202 by the gas source 110. The He ion generated by the interaction of the He gas atom with the first one of the three trimer atoms at the top of the tip 186 is guided by the ion optics 130 through the aperture 224 and directed at the sample 180.

In some embodiments, the potential applied to the tip 186 is 5 kV or higher (eg, 10 kV or higher, 15 kV or higher, 20 kV or higher). In certain embodiments, the potential applied to the tip 186 is 35 kV or less (eg, 30 kV or less, 25 kV or less). For example, in some embodiments, the potential applied to the tip 186 is 5 kV to 35 kV (eg, 10 kV to 30 kV, 15 kV to 25 kV).

In some embodiments, the pressure of the He gas is 10 during operation of the microscope system 200.^-8Torr or higher (eg 10^-7Torr and above, 10^-6Torr and above, 10^-5Torr and above). In certain embodiments, the pressure of the He gas in the microscope system 200 is 10.^-1Below Torr (eg 10^-2Below Torr, 10^-3Below Torr, 10^-4Below Torr). For example, in some embodiments, the pressure of the He gas in the microscope system 200 is 10.^-7Torr ~ 10^-1Torr (eg 10^-6Torr ~ 10^-2Torr, 10^-5Torr ~ 10^-3Torr).

To check the integrity of the tip 186, the field emission pattern from the tip 186 can be monitored periodically by operating the microscope system 200 in FIM or SFIM mode as described above. If the trimer structure remains intact at the tip apex 187, then the tip 186 can be used to continue supplying the ion beam 192 to the microscope system 200. However, under certain circumstances, FIM or SFIM images of the tip may reveal that the trimer structure is no longer intact at the tip apex 187. In this case, the tip 186 is first electrovaporated, the tip is rounded to remove the damaged trimer structure, and then the above process is performed in place (eg, without removing the tip 186 from the microscope system 200). ) Can be re-polished.

Monitoring of field emission patterns from tip 186 is automatic based on criteria such as reduced performance (eg, reduced ion current), observed imaging aberrations and / or errors, and other planned criteria. be able to. Since the FIM image of the tip 186 is captured, the sample 180 can be removed from that position, and a detector such as a CCD detector bound with a phosphor can be installed at the original position of the sample 180. Alternatively, a flat sample with relatively high secondary electron emission can be translated into place instead of sample 180, and a suitable detector is installed and by interaction of He ions with the sample. It may be configured to detect secondary electrons emitted from the sample. The aperture 224 can be removed (or a large diameter opening 225 can be selected) so that the ions generated from the interaction of the He gas atom with the tip 186 are not significantly disturbed. These operations can be automated.

Since the SFIM image of the tip 186 is captured, a detector can be introduced and the aperture 224 can be kept in an appropriate position as described for FIM imaging. Using the alignment deflectors 220 and 222, the ion emission pattern of the tip 186 can be rasterized over the aperture 224, and an image of the tip 186 can be obtained for each pixel. Acquisition of one or more images of the tip 186 by an electronic control system 170 that can control the placement of the aperture, the movement of the sample and detector, and the potential applied to the tip 186 and the alignment deflectors 220 and 222. Can be automated.

Referring to FIG. 13, as a result of generally aligning the longitudinal axis 207 of the tip 186 with the longitudinal axis 132 of the ion optical instrument 130 by the axis alignment means described above, between the axes 207 and 132 at the top 187 of the tip 186. The distance d is less than 2 mm (eg, less than 1 mm, less than 500 μm, less than 200 μm). In some embodiments, the angle between the axes 207 and 132 at the top 187 of the tip 186 is 2 ° or less (eg, 1 ° or less, 0.5 ° or less, 0.2 ° or less).

The extraction unit 190 includes an opening 191. In general, the shapes of the extraction unit 190 and the opening 191 can be selected as desired. Generally, those features are selected so that He ions can be efficiently and reliably directed into the ion optics 130. For example, as shown in FIG. 13, the extraction unit 190 has a thickness t measured in the z direction._eIt also has an opening 191 with a width a measured in the x direction and is located at a distance e measured in the z-axis direction from the top 187 of the tip 186. In some embodiments, t_eIs 100 μm or more (for example, 500 μm or more, 1 mm or more, 2 mm or more) and / or t_eIs 10 mm or less (for example, 7 mm or less, 5 mm or less, 3 mm or less). In certain embodiments, the distance e between the top 187 of the tip 186 and the extractor 190 is 10 mm or less (eg, 8 mm or less, 6 mm or less, 5 mm or less, 4 mm or less, 3 mm or less, 2 mm or less, 1 mm or less). In some embodiments, the extraction unit 190 is located further in the + z direction than the tip 186, as shown in FIG. In certain embodiments, the extraction unit 190 is located further in the -z direction than the tip 186. In such an embodiment, for example, the tip 186 protrudes through the extraction unit 190 and further extends along the z-axis from the extraction unit 190 in the + z direction. The extractor 190 is shown in FIG. 13 to have a particular configuration, but more generally, the extractor 190 can be of any desired design. For example, in some embodiments, the opening 191 can have curved sides of any desired shape.

Normally, the extraction unit 190 can be biased positively or negatively with respect to the tip 186. In some embodiments, the potential applied to the extraction unit 190 is -10 kV or higher (eg, -5 kV or higher, 0 kV or higher) and / or 20 kV or lower (eg, 15 kV or lower, 10 kV or lower) with respect to the tip 186. Is.

Further, the suppressor 188 can optionally exist in the vicinity of the tip 186. Using the suppressor 188, for example, the electric field distribution in the vicinity of the tip 186 can be changed by adjusting the potential applied to the suppressor 188. A suppressor 188 can be used with the extractor 190 to control the trajectory of the He ions produced at the tip 186. The suppressor 188 has a width k measured in the x direction and a thickness t measured in the z direction._sIt has an opening of and is located at a distance s from the top of the tip 186 measured in the z direction. In some embodiments, k is greater than or equal to 3 μm (eg, greater than or equal to 4 μm, greater than or equal to 5 μm) and / or less than or equal to 8 μm (eg, greater than or equal to 7 μm, less than or equal to 6 μm). In certain embodiments, t_sIs 500 μm or more (for example, 1 mm or more, 2 mm or more) and / or 15 mm or less (for example, 10 mm or less, 8 mm or less, 6 mm or less, 5 mm or less, 4 mm or less). In some embodiments, s is 5 mm or less (eg, 4 mm or less, 3 mm or less, 2 mm or less, 1 mm or less). In certain embodiments, the suppressor 188 is located further along the + z direction than the tip 186, as shown in FIG. In some embodiments, the tip 186 is located further along the + z direction than the suppressor 188, so that the tip 186 passes through the suppressor 188 and extends in the + z direction.

In general, the microscope system 200 can be configured such that the ion energy in the ion beam 192 can be selected as desired after passing through the extraction unit 190. Generally, the average ion energy in the ion beam 192 is 5 keV or more (for example, 10 keV or more, 20 keV or more, 30 keV or more) and / or 100 keV or less (for example, 100 keV or more) after passing through the inlet opening 133 to the ion optical device 130. 90keV or less, 80keV or less, 60keV or less, 50keV or less, 40keV or less, 30keV or less). For example, in some embodiments, the ion energy in the ion beam 192 is 5 keV to 100 keV (eg, 10 keV to 90 keV, 20 keV to 80 keV) after passing through the inlet opening 133. For example, in embodiments where it is preferable to detect ions that permeate through the sample, high ion energy (eg, 50 keV to 100 keV) can be used.

Further, in certain embodiments, the ion energy in the ion beam 192 can be changed without changing the ion current. That is, the potential applied to the tip 186 can be adjusted to change the average energy of the ion beam 192 without substantially changing the ion beam current from the ion beam 192.

C. Ion optics Referring to FIG. 14, the ion beam 192 enters the ion optical instrument 130 from the gas electric field ion source 120 through the inlet opening 133. First, the ion beam 192 passes through the first lens 216. The position and potential of the first lens 216 are usually chosen to focus the ion beam 192 at intersection C, where point C is the distance p from aperture 224 measured in the z direction. Generally, the first lens 216 is located at a distance f from the inlet opening 133 measured in the z direction. In some embodiments, the distance f is greater than or equal to 5 mm (eg, greater than or equal to 10 mm, greater than or equal to 15 mm) and / or less than or equal to 30 mm (eg, greater than or equal to 25 mm, less than or equal to 20 mm).

In general, the first lens 216 can be positively or negatively biased with respect to the tip 186. In some embodiments, the potential applied to the first lens 216 is -30 kV or higher (eg, -20 kV or higher, -10 kV or higher) and / or 40 kV or lower (eg, 30 kV or lower, 20 kV) with respect to the tip 186. Below, 15 kV or less, 10 kV or less).

In general, the distance p can be 1 mm or more (for example, 5 mm or more, 10 mm or more) and / or 100 mm or less (for example, 70 mm or less, 50 mm or less, 30 mm or less, 20 mm or less). Changing the position of point C can change the size of the ion beam 192 at the position of the aperture 224 in the x and / or y directions, and select the fraction of ions in the ion beam 192 passing through the aperture 224. Can be controlled as a target. In FIG. 14, it is shown to be located further in the -z direction than the aperture 224, but in some embodiments, the intersection C can be located further in the + z direction than the aperture 224.

Alignment deflectors 220 and 222 are configured to direct a portion of the ion beam 192 through the aperture 224 and the second lens 226. The deflector can be assembled with various designs and / or parts. In some embodiments, for example, the deflectors 220 and 222 can be quadrupole electrodes, respectively, with two quadrupole electrodes arranged in succession.

The deflectors 220 and 222 can deflect the ion beam 192 in both the x and y directions, respectively. The potential applied to the electrodes of the deflectors 220 and 222 can be adjusted to ensure that part of the ion beam 192 passes through both the aperture 224 and the second lens 226. In certain embodiments, the potentials applied to the deflectors 220 and 222 are adjusted to achieve a particular alignment condition, after which the potentials remain unchanged while the microscope system 200 is in operation. is there. For example, the alignment of the ion beam 192 through the aperture 224 is evaluated by observing the ion beam 192 with an appropriate detector configured to image the aperture 224. Also, the deflectors 220 and 222 can be adjusted so that a portion of the ion beam 192 passing through the aperture 224 is aligned with the longitudinal axis of the second lens 226. In order to evaluate the alignment of the ion beam 192 passing through the second lens 226, the potential applied to the second lens 226 can be changed (usually called blur), and the result is observed with an image detector. To do. If the image of the ion beam 192 changes in magnitude but not in position as a result of the change potential applied to the second lens 226, then the ion beam 192 is aligned through the second lens 226. When the center position of the ion beam 192 changes as a result of the change potential, the ion beam 192 at that time is not aligned with the second lens 226. In this case, the potential applied to the deflectors 222 and / or 220 can be further adjusted and the shake test is repeated until alignment is achieved.

In general, the potentials applied to the various electrode elements of the alignment deflectors 220 and 222 are selected as desired, creating a deflection of the ion beam 192 to a particular position with respect to the aperture 224 and the second lens 226. The electrodes of the deflectors 220 and 222 can be biased positively or negatively with respect to a common external ground. Generally, the potential applied to any electrode can be 100 V or less (eg, 75 V or less, 50 V or less) and / or 10 V or more (for example, 25 V or more, 40 V or more) with respect to a common external grounding portion. .. For example, the potential applied to any electrode of the deflectors 220 and 222 during operation can be 10V to 100V (eg, 10V to 75V, 10V to 50V) with respect to a common external grounding portion.

The aperture 224 is positioned so that a part of the ions in the ion beam 192 passes through the ion beam 192. Generally, the aperture 224 does not have an applied potential. In some embodiments, the width w of the opening 225 in the aperture 224 measured in the x direction is 1 μm or greater (eg, 2 μm or greater, 5 μm or greater, 10 μm or greater, 15 μm or greater, 20 μm or greater, 25 μm or greater, 30 μm. And / or 100 μm or less (for example, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less). In certain embodiments, for example, w is 1 μm to 100 μm (eg, 5 μm to 90 μm, 15 μm to 50 μm, 20 μm to 50 μm). In some embodiments, the width of the opening 225 in the aperture 224 measured in the y direction is 1 μm or greater (eg, 2 μm or greater, 5 μm or greater, 10 μm or greater, 15 μm or greater, 20 μm or greater, 25 μm or greater, 30 μm or greater). And / or 100 μm or less (for example, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less). In certain embodiments, for example, w is 1 μm to 100 μm (eg, 5 μm to 90 μm, 15 μm to 50 μm, 20 μm to 50 μm).

The diaphragm 224 is located on the diaphragm mounting portion 234. The aperture mounting section 234 allows translation of the aperture 224 in the xy plane by controlling the signal received from the electronic control system 170. Also, in some embodiments, the diaphragm attachment 234 allows the diaphragm 224 to translate along the longitudinal axis 132 of the ion optical instrument 130 in the z direction. Further, in certain embodiments, the diaphragm mounting portion 234 allows the diaphragm 224 to be tilted with respect to the xy plane. By tilting the aperture 224, the longitudinal axis of the aperture 224 can be aligned with the longitudinal axis 132 of the ion optical instrument 130.

In some embodiments, the iris 224 can include multiple openings with different widths w. For example, FIG. 15 is a top view (along the z direction) of a disc-shaped diaphragm 224a including a plurality of openings 225a to 225 g. The diaphragm 224a is configured to rotate around a rotation axis 227 that coincides with the center of the diaphragm 224a. The center of each opening 225a to 225g is located at the same distance from the rotation axis 227. Therefore, the diaphragm disc 224a is rotated so that the selected aperture is located in the path of the ion beam 192, and if necessary, the diaphragm disc is used to ensure accurate alignment of the aperture with the ion beam 192. By translating the 224a, a diaphragm opening of a specific size can be selected.

FIG. 16 is a top view (along the z direction) of the rod-shaped diaphragm 224b including the plurality of openings 229a to 229e penetrating the diaphragm 224b. The size of the aperture can be selected by selecting the opening in the aperture 224b. This selection is made by moving the aperture 224b in a direction parallel to the arrow 221 and aligning one of the openings 229a-229e with the ion beam 192.

In general, the openings 225a-225g and 229a-229e have diameters that can be selected as desired. In some embodiments, for example, the diameter of any of the openings may be 5 μm or greater (eg, 10 μm or greater, 25 μm or greater, 50 μm or greater) and / or 200 μm or less (eg, 150 μm or less, 100 μm or less). it can. In certain embodiments, the diameters of the openings 225a-225g and / or 229a-229e can be 5 μm-200 μm (eg, 5 μm-150 μm, 5 μm-100 μm).

In some embodiments, devices other than the diaphragm are used to allow only some of the ions in the ion beam 192 to pass through the ion optics 130 and collide with the surface of the sample 180. For example, two vertical slits can be installed consecutively along the flight path of the ion beam.

The astigmatism corrector 218 is usually configured to reduce or eliminate astigmatism of the ion beam 192 depending on its shape, position along the path of the ion beam 192 and the applied potential. Astigmatism correctors 218 can be assembled using various components, but astigmatism correctors 218 are generally octupole electrodes located between the aperture 224 and the scanning deflectors 219 and 221. is there. In general, the eight electrodes of an octupole astigmatism corrector are divided into two groups of four electrodes, where the four electrodes (eg, the first of the four electrodes that are positively biased with respect to the tip 186). Adjust the voltage of the first controller configured to regulate the voltage of one group) and the voltage of the other four electrodes (eg, the second group of four electrodes negatively biased with respect to the tip 186). Equipped with a second controller. The electrodes of the first electrode group and the second electrode group are arranged so as to alternately form an octupole segment, where the adjacent segments have differently signed bias voltages. This electrode arrangement forms a cusp magnetic field that focuses the ion beam propagating along the longitudinal axis of the octupole and blurs the point of focus of the off-axis ion beam.

In general, each electrode of the octupole can be configured independently, so that the astigmatism corrector 218 enables highly sensitive control of the ion beam 192. In some embodiments, the potential applied to any of the electrodes of the astigmatism corrector 218 is -30V or higher (eg, -20V or higher, -10V or higher, -5V) with respect to the common external ground. (More than) and / or 30V or less (for example, 20V or less, 10V or less, 5V or less).

In addition to the alignment deflectors 220 and 222, the ion optics 130 includes scanning deflectors 219 and 221. The scanning deflectors 219 and 221 are generally located between the astigmatism corrector 218 and the second lens 226, but generally other arrangements of the scanning deflectors 219 and 221 are possible within the ion optics 130. Is.

Scan deflectors 219 and 221 are configured to scan the ion beam over the surface of sample 180. For example, the deflector 219 can be configured to deflect the ion beam 192 in the x direction, and the deflector 221 can be configured to deflect the ion beam 192 in the y direction. The composite deflection created by the deflectors 219 and 221 can align the ion beam 192 to a specific position on sample 180.

Generally, the potential applied to the deflectors 219 and 221 is adjusted to create a particular deflection of the ion beam 192. The applied potential can be systematically varied to allow raster scanning of the beam 192 over a portion of sample 180. In some embodiments, for example, the potential applied to the deflector 221 is gradually increased at regular intervals and the ion beam 192 is discontinuous in the y direction (eg, row by row) over the sample 180. Bias. At the same time, the potential applied to the deflector 219 is gradually increased to deflect the ion beam 192 in steps discontinuous in the x direction (eg, column by column) over the sample 180. Once the ion beam 192 has performed a complete scan across all columns by a gradual increase in potential applied to the deflector 219, the deflector allows the ion beam 192 to be deflected in the y direction with respect to the new row. You can choose the rate at which the potential applied to the 221 is increased. For each row, an increment of potential increase in the same step pattern can be applied to the detector to sweep the ion beam 192 in x-directional discontinuous steps.

In general, the scan deflector 219 and / or 221 can be formed from a plurality of electrodes. In some embodiments, for example, the scanning deflectors 219 and / or 221 can each include a pair of parallel plate electrodes. The electrodes of the deflector 219 can be oriented to deflect the ion beam 192 in a direction perpendicular to the deflection of the ion beam 192 produced by the deflector 221.

In certain embodiments, the scan deflectors 219 and / or 221 can have a more complex design. For example, scan deflectors 219 and / or 221 can include quadrupole and / or octupole electrodes. Each of these electrodes can be configured to provide deflection of the ion beam in a single direction in the xy plane or in more than one direction in the xy plane.

Each electrode element of the scanning deflectors 219 and 221 can be biased positively or negatively with respect to a common external grounding portion. Generally, the voltage applied to each electrode can be -150V or more (for example, -100V or more, -50V or more, -20V or more) and / or 150V or less (for example, 100V or less, 50V or less, 20V or less). it can. During operation, for example, the voltage applied to each electrode of the deflectors 219 and 221 can be -150V to 150V (for example, -100V to 100V, -50V to 50V, -20V to 20V).

In general, the position and potential of the second lens 226 is chosen to help the second lens 226 focus the ion beam 192 on the surface 181 of the sample 180. The potential applied to the second lens 226 can generally be positive or negative with respect to a common external grounding portion. In certain embodiments, the potential applied to the second lens 226 is -50 kV or greater (eg, -40 kV or higher, -30 kV or higher) and / or 40 kV or lower (eg, 30 kV or lower) with respect to the common external ground. , 20kV). The second lens 226 is arranged at a distance u measured in the z direction from the aperture 224. In some embodiments, u is 5 cm or more (eg, 10 cm or more, 15 cm or more) and / or 50 cm or less (eg, 45 cm or less, 40 cm or less, 35 cm or less, 30 cm or less, 25 cm or less, 20 cm or less).

The second lens 226 is arranged at a distance h (generally referred to as an operating distance) measured along the z-axis from the sample 180. In some embodiments, h is 2 mm or more (eg, 5 mm or more, 10 mm or more, 15 mm or more, 20 mm or more) and / or 200 mm or less (eg, 175 mm or less, 150 mm or less, 125 mm or less, 100 mm or less, 75 mm or less, 65 mm or less, 55 mm or less, 45 mm or less). In certain embodiments, h is 2 mm to 200 mm (eg, 5 mm to 175 mm, 10 mm to 150 mm, 15 mm to 125 mm, 20 mm to 100 mm). Generally, h is adjusted by adjusting the focusing plane of the lens 226 by changing the potential applied to the second lens 226 and translating the sample 180 (by the sample manipulator 140) to the new focal plane of the lens 226. be able to. The relatively large distance h made possible by the microscope system 200 offers many advantages. For example, a microscope system can be used to examine uneven samples with surface protrusions. Further, the sample can be tilted at a large angle with respect to the main axis of the ion beam 192. In some embodiments, for example, the angle between the normal of the surface 181 of the sample 180 and the spindle of the ion beam 192 is 5 ° or greater (eg, 10 ° or greater, 20 ° or greater, 30 ° or greater, 40 °). Above, 50 ° or more, 60 ° or more) and / or 85 ° or less (for example, 80 ° or less, 75 ° or less, 70 ° or less, 65 ° or less). In certain embodiments, the angle between the normal of the surface 181 of the sample 180 and the spindle of the ion beam 192 is 5 ° to 85 ° (eg, 10 ° to 80 °, 20 ° to 70 °, 30 ° to). 70 °, 40 ° ~ 60 °). In addition, the relatively large distance h also allows various detectors and other devices to be placed close to the incident region of the ion beam 192 on the surface 181 over a relatively large range of solid angles. It is possible to detect particles emitted from the sample throughout. In general, this is (eg, different types of detection)

In some embodiments, the cone half-width is 10 ° or more (eg, 15 ° or more, 20 ° or more, 25 ° or more) and / or 50 ° or less (eg, 45 ° or less, 40 ° or less, 35 ° or less). The second lens 226 is attached as a right-angled cone. In certain embodiments, the second lens 226 has a conical half-width of 10 ° to 50 ° (eg, 15 ° to 45 °, 20 ° to 40 °). The relatively small conical half-width for lens 226 has a wide tilt angle with respect to the ion beam 192 of sample 180 and a large volume of freedom in which detectors and other devices can be placed near the incident beam point on the surface 181. It brings many advantages, including space.

As mentioned above, in general, only the He ion generated by the interaction of the He atom with one of the trimer atoms at the top 187 of the tip 186 passes substantially through the aperture 224. However, in some embodiments, the components of the ion optics 130 (eg, the first lens 216 and / or the alignment deflectors 220, 222 and / or the aperture 224) are of He atoms and trimeric atoms. It can be installed so that a substantial fraction of He ions generated by the interaction with the two passes through the aperture 224. This can be done, for example, by proper selection of the potential applied to the first lens 216 and / or the deflectors 220, 222, and / or by varying the size of the aperture 224 (eg, in FIGS. 15 and 16). This can be achieved (by selecting different aperture openings on the aperture rotors or aperture bars shown respectively). In certain embodiments, the components of the ionic optics 130 (eg, first lens 216 and / or alignment deflectors 220, 222 and / or aperture 224) are associated with all three of the He gas atom and the trimeric atom. The substantial fraction of He ions generated by the interaction of the above can be installed so as to pass through the aperture 224. This can be done, for example, by proper selection of the potential applied to the first lens 216 and / or the deflectors 220, 222, and / or by varying the size of the aperture 224 (eg, in FIGS. 15 and 16). This can be achieved (by selecting different aperture openings on the aperture rotors or aperture bars shown respectively).

Optionally, one or more additional electrodes (eg, lenses, deflectors and / or other elements) can be placed along the path of the ion beam 192 in the ion optics 130. Additional electrodes can be placed, for example, behind the second lens 226 or can be introduced between existing elements. The additional electrode can be positively or negatively biased with respect to the tip 186 to perform functions such as increasing or decreasing the ion energy in the ion beam 192 in the ion optical instrument 130, and / or the orbit of the ion. Can be changed. For example, one or more acceleration electrodes can be placed in the vicinity of the sample 180 to change the energy of the ions in the ion beam 192 incident on the sample 180.

As another example, the ion optics 130 may include a negatively biased lens barrel liner tube (relative to a common external ground) to increase the ion energy in the ion beam at the surface 181 of sample 180. it can. The tube is biased to -50 kV or higher (eg, -25 kV or higher, -15 kV or higher, -10 kV or higher) and / or -1 kV or lower (eg, -3 kV or lower, -5 kV or lower) with respect to the common external ground. it can. In general, the tube can be placed at any position along the axis 132 of the ion optics 130, for example between the aperture 224 and the second lens. By accelerating the ions as they pass through the ion optics 130, certain, including, for example, shortening the interaction time between comparable charged ions that can help reduce the divergence of the ion beam 192. Benefits can be realized.

In some embodiments, biasing the sample 180 (eg, positively biasing if a reduction in ion energy in the ion beam 192 is preferred, or passively the ion energy in the ion beam 192) The ion energy in the ion beam 192 at the surface 181 of the sample 180 can be increased or decreased (by negative bias if an increase is preferred). At large angles of incidence of the ion beam 192, the cylindrical asymmetry of the electric field created by the biased sample 180 can create a prismatic effect, in which case the low energy ions in the ion beam 192 are in the x direction and Detected in greater amounts than high energy ions in the y direction, it results in increased spot size of the ion beam 192 on the surface 181 of sample 180 and other potentially undesirable consequences. Therefore, in some embodiments, the sample 180 is biased to change the ion energy in the ion beam 192 so that the angle between the ion beam 192 and the normal of the surface 181 is less than 6 ° (eg, for example. Less than 5 °, less than 4 °, less than 3 °, less than 1 °).

Although specific embodiments of the ion optics have been described, other embodiments of the ionic optics can also be used. When a particular electrode type (eg, quadrupole) is described as an example, the same effect can be achieved with one or more different electrode types (eg, quadrupole). Generally, a wide variety of ion optical systems can be used in the microscope system 200. In some embodiments, for example, the ion optics 130 includes only a single lens in addition to the deflector, diaphragm and other ion optics. In certain embodiments, the ion optics 130 includes a first lens and a second lens with a diaphragm between them.

As another example, in some embodiments, the ion optics include a first lens, a second lens, and an aperture between the first lens and the second lens, but no electrodes. In the ion optical instrument, the first lens can reduce the divergence of the ion beam (for example, the ion beam can be substantially aligned with the longitudinal axis of the ion optical system), and a part of the ion beam can be focused on the aperture by the aperture. It can block the passage and is designed so that the second lens can help focus the ion beam to a relatively small spot size on the sample surface. In such an embodiment, the ions in the ion beam reaching the surface of the sample can be generated primarily by the interaction of the He atom with the only atom of the trimer (eg, as described above). In some embodiments, approximately equal numbers of ions in the ion beam reaching the surface of the sample are generated by the interaction of the He atom with each of the three trimer atoms.

As an additional example, in certain embodiments, the ion optics include a first lens, a second lens, and an aperture between the first lens and the second lens, but no electrodes. In the ion optical instrument, the first lens can focus the ion beam toward the center of the opening in the diaphragm, and the ion beam focused by the diaphragm can diverge and pass through the diaphragm. The lens is designed to help focus the ion beam to a relatively small spot size on the sample surface. In such an embodiment, the ion beam reaching the surface of the sample can contain approximately equal numbers of ions generated by the interaction of the gas atoms with each of the three atoms in the trimer. If the top of tip 186 contains more than three atoms (eg, five or more atoms, seven or more atoms, nine or more atoms), the ion beam will be a gas atom and each atom at the top of tip 186. It can contain approximately equal numbers of atoms generated by the interaction.

As a further example, in some embodiments, the ion optics include a first lens, a second lens, and an aperture between the first lens and the second lens, but no electrodes. In the ion optical instrument, the first lens can reduce the divergence of the ion beam and direct the low divergence beam to the diaphragm, so that substantially all the ions in the ion beam pass through the diaphragm. It can be designed so that the second lens can help focus the ion beam to a relatively small spot size on the sample surface. In such an embodiment, the ion beam reaching the sample surface can contain approximately equal numbers of ions generated by the interaction of the gas atoms with each of the three atoms in the trimer. If the top of tip 186 contains more than three atoms (eg, five or more atoms, seven or more atoms, nine or more atoms), the ion beam will be a gas atom and each atom at the top of tip 186. It can contain approximately equal numbers of atoms generated by the interaction.

As another example, in certain embodiments, the ion optics include a first lens, a second lens, and an aperture between the first lens and the second lens, but no electrodes. In the ion optics, the first lens can partially focus the ion beam toward the aperture, and the aperture can block some of the ions in the ion beam from passing through the aperture (but still the ion beam). A relatively large fraction of the ions inside can pass through the aperture), and the second lens is designed to help focus the ion beam to a relatively small spot size on the sample surface. .. In such an embodiment, the ion beam reaching the sample surface can contain approximately equal numbers of ions generated by the interaction of the gas atoms with each of the three atoms in the trimer. If the top of tip 186 contains more than three atoms (eg, five or more atoms, seven or more atoms, nine or more atoms), the ion beam will be a gas atom and each atom at the top of tip 186. It can contain approximately equal numbers of atoms generated by the interaction.

D. Tip tilt and translation mechanism The tip manipulator 208 is configured to allow both translation of the tip in the xy plane and tilting of the tip 186 with respect to the axis 132 of the ion optics 130. FIG. 17 is a partial cross-sectional view of the microscope system 200 including a tip 186, a support assembly 520, and one embodiment of a tip manipulator. The tip manipulator 208 includes a shaft portion 502, a hemispherical portion 504, a shoulder portion 510, and a translation portion 514. The translation portion 514 is connected to a shaft portion 502 sized so that it can be fitted through the opening 516 of the shoulder portion 510. Further, the shaft portion 502 is connected to the base 508 and sequentially connected to the assembly 520. The shoulder portion 510 is in a position fixed to the hemispherical portion 504 by the static friction force between the surface 512 and the surface 513, and the translation portion 514 is the shoulder portion due to the static friction force between the surface 518 and the surface 519. It is in a fixed position with respect to 510.

Tip manipulator 208 provides translation of tip 186 in the xy plane. To translate the tip 206, a high pressure gas is introduced into the inlet 503. The high-pressure gas introduced into the injection port 503 can be, for example, a gas such as the atmosphere. Generally, the gas can be introduced at a pressure of 50 pounds per square inch (psi) or more (eg, 75 psi or more, 100 psi or more, 125 psi or more). As a result of the introduction of the high pressure gas, a force in the -z direction is applied to the translation 514 and separates from the shoulder 510. The applied force reduces the frictional force between the surfaces 518 and 519 (but not to zero) and applies a lateral force in the xy plane to translate the translation 514 with respect to the shoulder 510. Allows relocation. The tip 186 is translated in the xy plane when the translation 514 is rearranged. When the tip 186 is in the new position, the high pressure gas supply is stopped and the inside of the tip manipulator 208 is exhausted using one or more vacuum pumps to restore the strong static friction force between the surfaces 518 and 519. .. Tip 186 is firmly anchored in place as a result of the recovered strong static friction.

The tip manipulator 208 also provides an inclination of the tip 186 with respect to the axis 132 of the ion optics 130. To tilt the tip 186, introduce high pressure gas into the inlet 505. The high-pressure gas introduced into the injection port 505 can be, for example, a gas such as the atmosphere. Generally, the gas can be introduced at a pressure of 50 pounds per square inch (psi) or more (eg, 75 psi or more, 100 psi or more, 125 psi or more). As a result of the introduction of the high pressure gas, a force in the -z direction is applied to the shoulder portion 510 and separates from the hemispherical portion 504. The applied force reduces the frictional force between the surfaces 512 and 513 (but not to zero). Next, the shoulder portion 510 can be rearranged with respect to the hemisphere portion 504 by applying a lateral force that translates the shoulder portion in the direction indicated by the arrow 506. The translation of the shoulder portion 510 corresponds to the relative movement along the curved surface of the hemisphere portion 504. As a result of this movement, the angle between axis 132 and axis 207 (corresponding to the tilt angle of tip 186) changes. When the adjustment of the inclination of the tip 186 is completed, the supply of the high pressure gas is stopped and the inside of the tip manipulator 208 is exhausted to recover the static frictional force between the surfaces 512 and 513. Tip 186 is firmly anchored in place as a result of the recovered strong frictional force.

In some embodiments, as shown in FIG. 17, the tip manipulator 208 is configured such that the center of the radius of curvature R of the hemisphere portion 504 coincides with the position of the apex of the tip 186. As a result, when the tip 186 is tilted to change the angle between the axes 132 and 207, translation of the tip 186 in the xy plane does not occur. As a result, the tip manipulator 208 is used to move the orbit of the ions generated by the interaction between the gas atom and one of the tip atoms of the first lens 216 without causing translation of the tip 186 to the axis of the first lens 216. It can be aligned with the longitudinal axis.

In certain embodiments, the tip manipulator 208 can be configured to allow rotational movement around an additional axis. For example, in the embodiment shown in FIG. 17, when a high-pressure gas is introduced into the injection port 503 to reduce the frictional force between the surfaces 518 and 519 and enable translation of the parallel moving portion 514 in the xy plane, parallel movement is possible. By applying a torque suitable for the moving portion 514, the parallel moving portion 514 can also rotate around the shaft 207. This rotation can be performed separately or in addition to the translation of the tip 186 and the adjustment of the tilt of the tip 186.

E. Sample stand Again, referring to FIG. 5, the microscope system 200 includes a sample manipulator 140 for supporting the sample 180 and placing it in a suitable position. In response to the control signal from the electronic control system 170, the sample manipulator 140 can translate the sample 180 in each of the x, y and z directions. Also, in some embodiments, the sample manipulator 140 can rotate the sample 180 in the xy plane in response to a control signal. Further, in certain embodiments, the sample manipulator 140 can tilt the sample 180 out of the xy plane in response to a suitable control signal. Their degrees of freedom are adjusted independently to achieve a suitable orientation of the sample with respect to the ion beam 192.

As described in detail below, in some embodiments, the sample manipulator 140 is biased positively or negatively with respect to a common external grounding portion by applying a relatively small potential to the sample manipulator 140. be able to. For example, in some embodiments, a positive potential bias of 5 V or higher (eg, 10 V or higher, 20 V or higher, 30 V or higher, 40 V or higher, 50 V or higher) is applied to the manipulator 140 with respect to a common external grounding portion. It can help prevent the charged He ions from adhering to the surface 181 of the sample 180. In certain embodiments, -200V or higher (eg, -150V or higher, -100V or higher, -50V or higher, -40V or higher, -30V or higher, -20V or higher, -10V or higher,- A negative potential bias of 5V or higher) can be applied to the manipulator 140, for example, to help accelerate secondary electrons (which exit the surface 181 of the sample 180 by the interaction of ions with the sample 180) and move them away from the sample. , Ensure that secondary electrons can be detected by a well-configured detector. In general, the potential applied to the manipulator 140 can be selected as desired depending on the particular substance under study, the He ion current and the irradiation time of the sample.

F. Detector The detectors 150 and 160 are schematically represented in FIG. 5, which are positioned to detect particles from surface 181 of sample 180 (the surface on which the ion beam collides) and also detect. Vessel 160 is positioned to detect particles from surface 183 of sample 180. In general, a wide variety of different detectors can be used in the microscope system 200 to detect different particles, and in general, the microscope system 200 can include a desired number of detectors. The configuration of one or various detectors can be selected according to the particles to be measured and the measurement conditions. In some embodiments, a spectral decomposition detector can be used. Such a detector can detect particles of different energies and / or wavelengths, and can decompose the particles based on the energy and / or wavelength of each detected particle. In certain embodiments, the spectral decomposition detector comprises components capable of directing the particle to different regions of the detector based on the energy and / or wavelength of the particle.

Specific exemplary detectors and arrangements of detectors will be described below.

(i) Everhart-Thornley detector The Everhart-Thornley (ET) detector can be used to detect secondary electrons, ions and / or neutral particles. FIG. 18 shows a conceptual diagram of the ET detector 600 including the particle selector 601, the converter 602, the support 604, the photon detector 606 and the power supplies 607 and 608.

The particle selector 601 is made of a conductive material. In some embodiments, for example, the particle selector 601 is a metal grid or mesh with a metal filling factor of less than about 30% (eg, less than 25%, less than 20%, less than 10%, less than 5%). Can be done. Since most of the grid is space, particles that collide with the grid can pass through relatively unobstructed areas.

In certain embodiments, the particle selector 601 is formed of a metal ring or tube. For example, the particle selector 601 has an internal opening that allows the particles to pass through the ring or tube, which can be a ring or tube that is substantially cylindrical in shape. For example, the ring or tube can be formed from a highly conductive metal such as copper or aluminum.

More generally, the particle selector 601 can be formed from any open electrode structure, including passages for particles to pass through. The particle selector 601 can be formed from one or more electrodes, and the potential applied to the one or more electrodes can usually be selected as desired according to the type of particles being measured.

The converting substance 602 is formed of a substance capable of forming photons by interacting with charged particles (eg, ions, electrons). Exemplary materials include phosphor materials and / or scintillator materials (eg, crystalline materials such as yttrium-aluminum-garnet (YAG) and yttrium-aluminum-phosphate (YAP)). The support portion 604 is formed of a substance relatively permeable to photons formed by the converting substance 602.

During operation, the power supply 607 applies a relatively small voltage (eg, 500V or less, such as 100V to 500V) to the particle selector 601 (formed of a conductive material), and the power supply 608 is relatively A large voltage (eg, 5 kV or higher, 10 kV or higher) is applied to the conversion material 602. In an embodiment of measuring electrons (eg, secondary electrons) from sample 180 using an ET detector, the voltage signal applied to the particle selector 601 and the converting material 602 is positive with respect to sample 180. In an embodiment of measuring ions from sample 180 (eg, secondary ions, scattered ions) using an ET detector, the voltage signal applied to the particle selector 601 and the converting material 602 is negative with respect to sample 180. Is. Also, in certain embodiments, the sample 180 can be biased (relative to a common external ground) to help send particles from the sample 180 to the detector 600. For example, when measuring secondary electrons from sample 180 using an ET detector, the sample can be negatively biased against a common external ground. Applying a negative potential bias to the manipulator 140 can be particularly useful, for example, when detecting secondary electrons generated in high aspect ratio (eg, deep) holes or vias in a sample. A negative potential bias against a common external ground can help accelerate electrons emanating from holes or vias away from the sample, facilitating electron detection. When lacking a negative bias, many of the secondary electrons can instead return to the sample at points along the hole or via wall and never escape from the hole or via to be detected.

For example, when measuring ions from a sample using an ET detector, the sample 180 can be positively biased. The magnitude of the potential applied to bias the sample can be 5 V or higher (eg, 10 V or higher, 15 V or higher, 20 V or higher, 30 V or higher, 50 V or higher, 100 V or higher).

The charged particles 610 (eg, electrons or ions) from sample 180 are attracted to the particle selector 601, pass through the particle selector 601 and are accelerated towards the converting material 602. Next, the charged particles 601 collide with the converting substance 602 to generate photons 612. The photon 612 passes through the support 602 and is detected by the photon detector 606.

Although the operation of the ET detector has been described for the measurement of charged particles, in general, the particles that collide with the converting substance 602 do not need to be charged to generate photons, so the neutral particles are detected using the ET detector. You can also do it. In particular, the primary atom from sample 180 can collide with the converting material 602 and generate photons for detection by the photon detector 606. The photon detector 606 can be, for example, a photomultiplier tube (PMT), a diode, a diode array or a CCD camera.

An ET detector can be installed at an arbitrary position with respect to the sample 180 to detect neutral particles or charged electrons. Generally, for example, the ET detector is located adjacent to the second lens 226 of the ion optics 130. Optionally, the ET detector can be positioned to tilt slightly downward towards sample 180 (eg, with a configuration similar to that shown in the detector of FIG. 5).

In certain embodiments, the ET detector can be located near the surface 183 of sample 180. Such a configuration may be preferred, for example, when attempting to measure secondary electrons from sample 180 exiting surface 183 (eg, after passing through sample 180). In such an embodiment, the ET detector can have a configuration similar to that of the detector of FIG.

(ii) Photon detector A standard photon detector such as PMT can be used to detect photons generated by the interaction of ions with sample 180. If the photon flux emitted from sample 180 is large enough, low-sensitivity photon detectors such as diodes, diode arrays and CCD cameras can be used.

Also, in some embodiments, the photon detector may include, for example, various optical elements that can be configured to separate a particular optical signal of interest from other optical signals. For example, in certain embodiments, the photon detector may include an optical element, such as a filter, that selects a particular wavelength range of the photon signal emerging from the sample 180, providing material composition information for the sample 180. Can be done. For example, the filter can block photons of undesired wavelengths (eg, absorb photons of undesired wavelengths, reflect photons of undesired wavelengths, divert photons of undesired wavelengths). In some embodiments, the optics can spatially disperse different wavelengths to provide spectral resolution (eg, measuring the spectrum of photons generated by sample 180) (eg, one). One or more spectroscope systems that provide wavelength decomposition detectors for diffraction elements such as one or more diffraction gratings and / or refraction elements such as one or more prisms and / or photons). In some embodiments, the photon detector may include a polarizing manipulator such as a wave plate and / or a polarizer. These polarization manipulation elements can be configured to allow photons in only the selected polarization state to reach the PMT, for example, to detect the polarization selectivity of the photon signal emerging from sample 180. (For example, to help determine crystal orientation information for sample 180). In certain embodiments, the photon detector also includes a mirror, a lens, a beam splitter and other elements for redirecting and manipulating the incident photon (eg, increasing the solid angle of the detected photon). Can be done.

In general, a photon detector can be placed to detect photons at a desired angle and distance from sample 180. For example, in certain embodiments, the photon detector is a photon emerging from surface 181 (the surface of sample 180 on which the ion beam 192 is incident) or surface 182 (the surface of sample 180 opposite the surface on which the ion beam 192 is incident). Can be placed to detect. Optionally, multiple photon detectors are used to detect photons from surfaces 181 (the surface on which the ion beam collides), 183 (the surface opposite where the ion beam collides) and / or other surfaces of sample 180. Can be configured to:

In some samples, photons are scattered in a specific direction according to the selection rule of the optical process occurring in the sample 180, and the material composition information about the sample 180 is obtained by the angular decomposition measurement of the amount of photons emitted from the sample 180, for example. Can be provided.

(iii) Microchannel plate detector In some embodiments, a microchannel plate detector can be used to amplify a bundle of secondary electrons, neutral atoms or ions from sample 180. Microchannel plates are generally made of materials such as fused silica and usually include a large number of small diameter channels arranged in the form of an array. The particles enter the individual channels and collide with the channel walls to generate free electrons. In general, a plurality of free electrons are generated at each collision of a particle (neutral atom, ion or electron) with a channel wall surface. As a result, a cascade electronic signal corresponding to the amplification of the input particle signal emerges from the microchannel plate.

Microchannel plate detectors (which can include one or more microchannel plates) can be configured to detect ions, secondary electrons and / or neutral atoms from sample 180. Neutral particles and / or ions formed from sample 180 (eg, secondary and secondary atoms, scattered ions and primary atoms) generally exit from surface 181 of sample 180 (the surface on which the ion beam collides). Therefore, a microchannel plate detector configured to measure neutrals and / or ions from sample 180 is usually in a position similar to that of detector 150 shown in FIGS. 1 and 5. However, in certain embodiments, neutral particles and / or ions (eg, permeated ions) can be examined. In such an embodiment, the microchannel plate detector can be located at a position similar to that of the detector 160 in FIGS. 1 and 5. Secondary electrons can be detected from the surface 181 (the surface on which the ion beam collides) and / or the surface 183 (the surface opposite to where the ion beam collides) of the sample 180, and the secondary electrons are detected from the sample 180. The microchannel plate detectors configured to do so are in the same positions as the detectors 150 and / or the detectors 160 shown in FIGS. 1 and 5.

The microchannel plate amplifies the input particle signal and converts the input signal into an output electronic signal. To visualize the output electronic signal, the microchannel plate detector can also include transformants, screens and photon detectors (see above).

In some embodiments, the microchannel plate is attached directly to the element of the ion optics 130. FIG. 19 shows a cross-sectional view of the microchannel plate detector 620 mounted directly on the second lens 226. The second lens 226 has a conical shape and has a flat lower surface 622. The detector 620 is mounted directly on the surface 622. When the sample 180 is irradiated with the ion beam 192, the microchannel plate detector 620 can detect ions, secondary electrons and / or neutral atoms (collectively indicated by arrows 624) from the sample 180. The detector 620 can record a current proportional to the detected particle bundle and transmit it to the electronic control system 170.

(iv) Conversion plate In some embodiments, a conversion plate is used to detect ions from sample 180 (eg, scattered ions, secondary ions) or neutral particles from sample 180 (eg, primary neutral He atoms). Can be done. In general, the conversion plate can be formed from a thin foil material having a high amount of secondary electrons emitted when it hits an incident ion or atom. An example of such a substance is platinum. The amount of secondary electron emission produces a large number of secondary electrons that are easily detected by a suitable electron detector configured as, for example, detectors 150 and / or 160 (FIGS. 1 and 5).

(v) Channel Tron detector In addition, the channeltron detector can be used to detect particles such as electrons, ions, and neutral atoms emitted from the sample 180. The channeltron detector works by amplifying the particle signal by multiple internal collisions, similar to those described for the microchannel plate detector. Measurements of relatively weak secondary electron bundles, ion bundles or neutral atom bundles from sample 180 are made by measuring the amplified particle signal output by the channeltron detector (eg, using the electronic control system 170). It will be possible. When measuring secondary electrons from sample 180, the channeltron detector can be located in the same position as represented for detector 150 and / or detector 160 in FIGS. 1 and 5. Generally, for the measurement of ions and / or neutral particles from sample 180, the channeltron detector should be in a position similar to the position of detector 150 and / or detector 160 shown in FIGS. 1 and 5. is there.

(vi) Fluorescent detector The fluorescence system detector includes a thin layer of phosphor material deposited on a transparent substrate and a photon detector such as a CCD camera, PMT or one or more diodes, which is used from sample 180. It can detect electrons, ions and / or neutral atoms. The particles hit the phosphor layer and induce the emission of photons from the phosphor detected by the photon detector. The fluorescence system detector can be placed in the same position as the detector 150 and / or the detector 160 shown in FIGS. 1 and 5 depending on the type of particles to be measured (see description above).

(vii) Solid state detector A solids detector can be used to detect secondary electrons, ions and / or neutral atoms from sample 180. The solid state detector can be assembled from a sensor made of a substance such as silicon or a doped silicon material. When the incident particle hits the sensor, it creates an electron-hole pair in the sensor's material, creating a current that can be detected by the electronic control system 170. The number of electron-hole pairs generated by an incident particle and the magnitude of the corresponding current resulting from it are, in part, determined by the energy of the particle. Therefore, solid-state detectors can be particularly useful for measuring the energy of particles and can be particularly advantageous when detecting high-energy particles from sample 180 (eg, scattered He ions and neutral He atoms).

(viii) Scintillator detector Similar to fluorescence system detectors, scintillator system detectors include scintillator materials that hit incident particles (electrons, ions or neutral atoms) to generate photons. Suitable scintillator materials include, for example, YAG and YAP. The amount of photons emitted by the scintillator detector is determined by the energy of the incident particles. As a result, the scintillator detector can be particularly useful for measuring the energy of particles and can be particularly advantageous when detecting high energy particles from sample 180 (eg, scattered He ions and neutral He atoms). ..

(ix) Energy detector for ions A variety of different detection strategies can be performed using a variety of different detectors to measure the energy of ions (eg, scattered He ions) from sample 180. Incident ions can be deflected using an electric field and / or a magnetic field, and the ions can be spatially separated by different energies using an electrostatic prism detector whose amount of deflection is determined by the ion energy. It is also possible to spatially separate ions based on ion energy using a magnetic prism detector. The deflected ions can then be detected using any of the suitable detectors described above (eg, microchannel plates, channeltrons and others).

In addition, the quadrupole detector can be used to analyze the energy of ions from sample 180. In a quadrupole detector, a radio frequency (RF) field within the quadrupole ensures that ions with the selected mass and energy propagate along a straight, unbiased orbit within the quadrupole. Ions with different masses and / or energies propagate along curved orbits within the quadrupole. The ion energy can be determined from the deflection position of the ions in the quadrupole analyzer.

In some embodiments, a positively biased particle selector (eg, a screen or mesh of conductive material or a cylindrical metal tube or ring) is placed in front of the detector along the flight path of the ions. With, the ion energy can be determined. The magnitude of the potential applied to the particle selector 601 can be very high initially (eg, a value that appears to block the passage of ions from sample 180) and is suitable for detecting ions. The magnitude of the potential can be reduced while using a detector (see description above). The current of the ions reaching the detector depending on the magnitude of the potential bias on the particle selector can be used to determine information about the ion energy.

(x) Energy detector for electrons A variety of different detection schemes can be performed using a variety of different detectors to measure the energy of electrons (eg, secondary electrons) from sample 180. Incident electrons can be deflected using an electric field and / or a magnetic field, and electrons can be spatially separated by different energies using a prism detector whose amount of deflection is determined by electron energy. The deflected electrons can then be detected using any of the above suitable detectors.

In some embodiments, a negatively biased particle selector (eg, a screen or mesh of conductive material or a cylindrical metal tube or ring) is placed in front of the detector along the electron flight path. With, the electron energy can be determined. The magnitude of the potential of the particle selector can be very high initially (eg, a value that appears to block the passage of electrons from sample 180) and is a suitable detector for detecting electrons (above). The magnitude of the potential can be reduced while using (see description). The electron current that reaches the detector depending on the magnitude of the potential applied on the particle selector can be used to determine information about electron energy.

(xi) Flight time detector The detector can also be configured to measure flight time information for secondary electrons, ions and neutral atoms. To detect the flight time, the ion beam 192 is operated in pulse mode. For example, the ion beam 192 can be pulsed by rapidly changing the potential applied to one or both of the detectors 220 and 222. By increasing these potentials, for example, the ion beam 192 can be deflected from the normal path of the ion optical instrument 130, so that the ion beam 192 is temporarily blocked by the aperture 224. A pulse of He ions can then be sent to sample 180 if the potentials of detectors 220 and 222 are then returned to their normal values in a short time before being increased again.

At the same time, the detectors 150 and 160 can be synchronized with the clock signal from the electronic control system 170 based on the temporal change of the potential applied to the deflectors 220 and / or 222. As a result, the period from the start of the He ion pulse to the detection of particles from the sample 180 can be accurately measured. From the known information about the propagation time of the He ion pulse in the ion optics 130, the flight time of the detected particles between the sample 180 and the detectors 150 and / or 160 can be determined.

(xii) Angle-dependent measurement In addition to measuring the relative abundance and energy of particles from sample 180, angle-dependent scattering information can be obtained using the detector described above. Generally, to obtain angle-dependent information, a detector is attached to a mounting portion (eg, a rotating mounting portion) that allows the detector to move over a series of solid angles for sample 180. Record measurements of particle abundance and / or energy with respect to sample 180 in a predetermined orientation corresponding to a particular solid angle. The detectors are continuously rearranged at different solid angles, the measurements are repeated, and the angle dependence of the measured quantity is determined. In some embodiments, a limiting diaphragm such as a pinhole may be placed in the path of the scattered particles in front of the detector to further limit the angular range for measuring the particles from sample 180.

G. Operating parameters The ion beam 192 can have a relatively small spot size on the surface 181 of the sample 180. For example, in one embodiment, the spot size of the ion beam 192 on the surface 181 of the sample 180 is 10 nm or less (eg, 9 nm or less, 8 nm or less, 7 nm or less, 6 nm or less, 5 nm or less, 4 nm or less, 3 nm or less. , 2 nm or less, 1 nm or less) dimensions. In certain embodiments, the spot size of the ion beam 192 on the surface 181 of sample 180 is 0.05 nm or greater (eg, 0.1 nm or greater, 0.2 nm or greater, 0.25 nm or greater, 0.5 nm or greater, 0.75 nm or greater, 1 nm). Above, it has dimensions of 2 nm or more and 3 nm or more). In some embodiments, the spot size of the ion beam 192 on the surface 181 is 0.05 nm to 10 nm (eg, 0.1 nm to 10 nm, 0.2 nm to 10 nm, 0.25 nm to 3 nm, 0.25 nm to 1 nm, 0.1 nm). ~ 0.5nm, 0.1nm ~ 0. It has a dimension of 2 nm). As used in the present application, the spot size is determined as follows with reference to FIGS. 20A-20C. Island-like particles 1700 formed of gold and having dimensions of 50 nm to 2000 nm are placed on the carbon surface 1710. The island-shaped gold particles are formed, for example, by vapor deposition of gold on the carbon surface. The measurement sample containing the island-shaped gold particles deposited on carbon is suitable for the measurement of the resolution described in the present application, and is commercially available from, for example, Structure Probe Incorporated (West Chester, PA). The ion microscope can be operated so as to move the ion beam 192 linearly across a part of the island-shaped gold particles and a part of the carbon surface on one side of the island-shaped gold particles (arrow 1730). The intensity of secondary electrons is measured according to the position of the ion beam (Fig. 20C). Calculate (or subtract) the asymptote 1740 and 1750, which correspond to the average total abundance for carbon and gold, and the total abundance is 25% of the asymptote difference between the asymptote 1740 and the asymptote 1750, respectively. Calculate (or draw) the vertical lines 1760 and 1770 that correspond to the 75% position. The spot size of the ion microscope 200 is the distance between line 1760 and line 1770.

Generally, the current of the ion beam 192 on the surface 181 of the sample 180 is 1 nA or less (for example, 100 pA or less, 50 pA or less) and / or 0.1 fA or more (for example, 1 fA or more, 10 fA or more, 50 fA or more, 100 fA or more, 1 pA or more). , 10pA or more). For example, in some embodiments, the current of the ion beam 192 on the surface 181 of the sample 180 is 0.1 fA to 1 nA (eg, 10 fA to 100 pA, 100 fA to 50 pA). In certain embodiments, it may be preferable to use a relatively low beam current when imaging the sample. For example, in some biological and / or pharmaceutical applications, it may be important to use low currents to image the sample (eg, to reduce the potential for damage to the sample). is there. In such an embodiment, one current amount can be used to prepare a gas electric field ion microscope for use (eg, a current of 10 fA or greater), and different current amounts are used to image the sample. Can be (eg, current less than 1fA, such as 0.1fA).

Generally, the ion beam 192 has an energy spread of 5 eV or less (for example, 4 eV or less, 3 eV or less, 2 eV or less, 1 eV or less, 0.5 eV or less) on the surface 181 of the sample 180. In some embodiments, the ion beam 192 has an energy spread of 0.1 eV or greater (eg, 0.2 eV or greater, 0.3 eV or greater, 0.4 eV or greater) on the surface 181 of sample 180. For example, the ion beam 192 can have an energy spread of 0.1 eV to 5 eV (eg, 0.1 eV to 3 eV, 0.1 eV to 1 eV) on the surface 181 of the sample 180.

The ion beam 192 can have a relatively high brightness on the surface 181 of the sample 180. For example, the ion beam 192 is 1 × 10 on the surface 181 of sample 180.⁹A / cm²sr (eg 1x10¹⁰A / cm²sr or more, 1x10¹¹A / cm²It can have a brightness of sr or more). In some embodiments, the brightness can be increased by increasing the gas pressure adjacent to the tip 186 and / or lowering the temperature of the tip 186. As referred to the present application, the brightness of the ion beam is measured as follows. The FWMH of the ion orbital distribution in the ion beam 192 (in the spatial region between the extraction section 190 and the first lens 216, where the net electric field is relatively small and the ion orbit is approximately straight), is in both the x and y directions. Is determined by. A total of 100 ion orbitals within the FWHM width in both the x and y directions are randomly selected from the ion orbital distribution in the ion beam 192. Each of the 100 ion orbitals is approximately straight and projected in the direction back to the top of the tip 187. Specific point z along the z-axis_tThe spatial extent of the orbit at is parallel to the xy plane and the point z_tPlane Z passing through_tIn the plane Z of the backward propagation orbit_tIt is evaluated by constructing a circle with the smallest diameter that surrounds all of the intersections with. The diameter of the smallest circle is d_sIs. Generally, a point z near the top of the tip 187_tThen d_sBecomes smaller and points closer to sample 180 z_tThen d_sBecomes larger. Specific point z_t= z₀In d_sIs the minimum value d₀Will be. That is, the spatial spread of the orbit in the plane parallel to the xy plane is minimized. Point z₀Diameter of the smallest circle in₀Is referred to as the size of the virtual source of the microscope system 200. Next, as described above, the divergence and beam current of the ion beam 192 in the FWHM region of the ion beam 192 between the extraction unit 190 and the first lens 216 are measured. Finally, the brightness is calculated by dividing the beam current by the product of the virtual source size and the three-dimensional divergence angle of the ion beam 192.

The ion beam 192 can have a relatively high reduction brightness on the surface 181 of the sample 180. For example, the ion beam 192 is 5 × 10 on the surface 181 of sample 180.⁸A / m²srV or higher (for example, 1x10⁹A / m²srV, 1x10¹⁰A / m²It can have a reduced brightness of srV). As referred to the present application, the reduced brightness of an ion beam is the brightness of the ion beam divided by the average ion energy in the ion beam at the position where the beam current is measured.

The ion beam 192 can have a relatively low etandu at the distal end 193 of the extraction unit 190. For example, the ion beam 192 is 5 × 10 at the distal end 193 of the extraction unit 190.^-21cm²Below sr (eg 1x10^-22cm²sr or less, 1 × 10^-23cm²sr or less, 1 × 10^-23cm²sr or less, 1 × 10^-24cm²It can have etandu (less than or equal to sr). As referred to the present application, the ethandue of an ion beam is calculated as the mathematical product of the reciprocal of brightness and the beam current.

The ion beam 192 can have a relatively small reducing etandu at the distal end 193 of the extraction unit 190. For example, the ion beam 192 is 1 × 10 at the distal end 193 of the extraction unit 190.^-16cm²Below sr (eg 1x10^-17cm²sr or less, 1 × 10^-18cm²sr or less, 1 × 10^-19cm²It can have reduced etandu (less than or equal to sr). The reduced ethanedu of an ion beam is the mathematical product of the ethanedu of the ion beam and the ratio of the average energy to charge of the ions in the ion beam at the position where the beam current is measured.

The ion beam 192 can have a relatively low angular convergence with respect to the surface 181 of the sample 180. For example, in some embodiments, the convergence half-width of the ion beam 192 can be 5 mrad or less (eg, 1 mrad or less, 0.5 mrad or less, 0.1 mrad or less) and / or 0.05 mrad or more. As referred to the present application, the convergence half-width of the ion beam is determined as follows. As a result of mounting the sample containing the island-shaped gold particles on the carbon substrate as described above and translating it in the z direction, the focal position of the ion beam 192 is along the diameter of the island-shaped gold particles. It is located as close as possible to the highest altitude point. Next, as described above, the ion beam 192 is linearly translated along the diameter of the island-shaped gold particles, and the focused spot size of the ion beam s._fTo measure. Next, translate the sample in the + z direction and s_zThe unfocused spot size of the ion beam 192 is translated by moving the ion beam 192 linearly along the same diameter of the island-shaped gold particles at 1 μm away from the ion optical device 130._dTo measure. Next, the convergence angle η can be determined by the trigonometry from the measurement of the focused spot size and the unfocused spot size together with the translation distance as shown in the following equation.<maths num="1"><img file="JP2009517841A_D0003.tif" /></maths> The convergence half-width of the ion microscope 200 is η / 2.

The ion microscope 200 can be very reliable. As an example, in some embodiments, a He ion source (tip 186, extractor 190, and optional suppressor 188) interacts continuously with gas atoms for a week without removing tip 186 from the system. It is possible to generate an ion beam for the above (for example, two weeks or more, one month or more, two months or more). In some embodiments, the current of the ion beam 192 on the surface 181 of the sample 180 is 10% or less per minute (during the period in which the He ion source interacts continuously with the gas atom to generate the ion beam). For example, it changes by 5% or less, 1% or less).

As another example, in some embodiments, a gas electric field ion source (tip 186, extractor 190, and optional suppressor 188) interacts with the gas atom for a total of 10 hours or less (eg, 5 hours or less). , 2 hours or less, 1 hour or less), and it is possible to generate an ion beam for 1 week or more (for example, 2 weeks or more, 1 month or more, 2 months or more). In such an embodiment, the gas electric field ion source can interact with the gas atom to generate an ion beam continuously (corresponding to a total interruption time of zero hours), which is necessary. is not it. For example, during that period, the gas electric field ion microscope may not interact with gas atoms to generate an ion beam. During that period, the interruption time may occur once or more than once (eg, 2, 3, 4, 5, 6, 7, 8, 9, 10). is there. The interruption may be due to, for example, regular maintenance, unforeseen maintenance and / or downtime between shifts (eg, overnight downtime). The total suspension time during that period is the total suspension time. As an example, if there are three 1-hour breaks during that period, the total break time is 3 hours. As another example, if there is only one break during that period, which is 3 hours, then the total break time is 3 hours. As a further example, if there are two breaks during that period, the first break is 1 hour and the second break is 2 hours, then the total break time is 3 hours. Is. In some embodiments, the current of the ion beam 192 on the surface 181 of the sample 180 is 10% or less per minute (eg, during the period when this gas electric field ion source interacts with the gas atom to generate an ion beam). , 5% or less, 1% or less).

The ion microscope 200 can have a relatively good resolution. For example, in some embodiments, the resolution of the ion microscope 200 is 10 nm or less (for example, 9 nm or less, 8 nm or less, 7 nm or less, 6 nm or less, 5 nm or less, 4 nm or less, 3 nm or less, 2 nm or less, 1 nm or less). be able to. In a particular embodiment, the resolution of the ion microscope 200 is 0.05 nm or more (for example, 0.1 nm or more, 0.2 nm or more, 0.25 nm or more, 0.5 nm or more, 0.75 nm or more, 1 nm or more, 2 nm or more, 3 nm or more). be able to. In some embodiments, the ion microscope 200 has a resolution of 0.05 nm to 10 nm (eg, 0.1 nm to 10 nm, 0.2 nm to 10 nm, 0.25 nm to 3 nm, 0.25 nm to 1 nm, 0.1 nm to 0.5 nm, 0.1 nm to It can be 0.2 nm). As used in this application, the resolution of an ion beam refers to the size of the smallest feature that can be accurately measured from an image obtained using an ion microscope. The size of the feature is within an error of 10% or less of the actual size of the feature and less than 5% of the actual size of the feature from the 10 images of the feature obtained under similar conditions. It is measured accurately if it can be determined by the standard deviation of the measured magnitude of.

High quality images can be taken in a relatively short time using the ion microscope 200. For example, the ion microscope 200 can have a quality coefficient of 0.25 or more (for example, 0.5 or more, 0.75 or more, 1 or more, 1.5 or more, 2 or more). As referred to the present application, the quality factor is determined as follows. A planar sample, one made of silicon (Si) and the other made of copper (Cu), with a boundary with a linear material across the sample, is positioned so that the boundary is oriented parallel to the y-axis. ing. The sample is imaged pixel by pixel by dividing the surface of the sample into a 512 pixel x 512 pixel xy array. During the measurement, the residence time per pixel is 100 ns. The total abundance of secondary electrons from the sample is measured according to the position of the ion beam on the surface of the sample. For image pixels corresponding to Si in the sample, the standard deviation SD from the Si pixel intensity distribution₁In addition to the average pixel strength G₁To decide. For image pixels corresponding to Cu in the sample, the standard deviation SD from the Cu pixel intensity distribution₂In addition to the average pixel strength G₂To decide. The quality coefficient is calculated according to the following formula.<maths num="2"><img file="JP2009517841A_D0004.tif" /></maths>

The surface 181 of sample 180 may be relatively minorly damaged when irradiated with an ion beam 192. For example, the surface 181 of sample 180 can have values of 25 nm or less (eg, 20 nm or less, 15 nm or less, 10 nm or less, 5 nm or less) according to the damage test. As referred to the present application, the damage test is performed as follows. For an atomically flat silicon (purity 99.99%) sample with a field of 4 square μm, use the ion beam current of the sample at 10 pA and the spot size of the ion beam at the sample of 10 nm or less, and ionize over the surface of the sample. The beam is imaged for 120 seconds while rasterizing each pixel. The 4 square μm field of view is decomposed into an array of 512 pixels × 512 pixels for the purpose of rasterization. The damage test value corresponds to the maximum distance to etch the imaged portion of the silicon sample obtained from performing the damage test.

The ion microscope 200 can have a relatively large depth of focus. For example, in some embodiments, the depth of focus of the ion microscope 200 can be 5 nm or more (eg, 10 nm or more, 100 nm or more, 1 μm or more) and / or 200 μm or less (for example, 100 μm or less, 10 μm or less). .. In some embodiments, the depth of focus of the ion microscope 200 can be 200 μm to 5 nm (eg, 500 μm to 5 nm, 1 nm to 5 nm). As used in the present application, the depth of focus of an ion beam is measured by the method shown below. The sample containing the island-shaped gold particles formed on the carbon substrate (as described above regarding the measurement of the spot size of the He ion beam) is inserted into the He ion microscope, and the spot size of the He ion beam is described as described above. To measure. By repeatedly adjusting the position of the sample along the z-axis, the position of the sample that results in the minimum He ion beam spot size is determined. The position along this z axis is z_fIs shown. z_fHe ion beam spot size at ss_fIs shown. Then z_fThe sample is gradually translated along the -z direction. After continuous gradual translation (z_fMeasure the spot size of the He ion beam (at the same position on the sample used to determine). The spot size of the measured He ion beam is 2ss_fWhen is, the translation of the sample is stopped. The position of the sample along this z-axis is z_uIs shown. Then z_uGradually translate the sample along the + z direction with respect to point z_fGo through. After continuous gradual translation (z_fMeasure the spot size of the He ion beam (at the same position on the sample used to determine). The spot size of the measured He ion beam is 2ss_fWhen is, the translation of the sample is stopped. The position of the sample along this z-axis is z₁Is shown. Depth of focus of He ion microscope d_fIs d_f= | z₁-z_uCalculated as |

In some embodiments, a gas field ion microscope disclosed herein (eg, a He ion microscope) is used, eg, for secondary electron emission, scattered ion abundance and / or angle and energy-decomposed scattered ions. Detection can distinguish elements in samples that have very close atomic numbers (Z values). For example, in certain embodiments, a gas electric field ion microscope can be used to distinguish between elements having atomic numbers (Z values) that differ by one.

In certain embodiments, a gas field ion microscope disclosed herein (eg, a He ion microscope) is used to detect, for example, secondary electron emission, scattered ion abundance and / or angle and energy-decomposed scattered ions. Allows you to distinguish the elements in the sample that have very close masses. In certain embodiments, a gas field ion microscope is used to use a gas field ion microscope to use a gas field ion microscope to: 1 or less (eg, 0.9 or less, 0.8 or less, 0.8 or less, 0.7 or less, 0.6 or less, 0.6 or less, 0.5 or less. Elements with different masses can be distinguished by (less than a unit, less than 0.4 atomic mass units, less than 0.3 atomic mass units, less than 0.2 atomic mass units, less than 0.1 atomic mass units). In some embodiments, the sample can have a domain formed of a substance (eg, an alloy) having a different average mass. In such an embodiment, for example, using a gas electric field ion microscope, 1 atomic mass unit or less (for example, 0.9 atomic mass unit or less, 0.8 atomic mass unit or less, 0.7 atomic mass unit or less, 0.6 atomic mass unit or less, 0.5 atom) It is possible to distinguish domains of substances having different masses by mass unit or less, 0.4 atomic mass unit or less, 0.3 atomic mass unit or less, 0.2 atomic mass unit or less, 0.1 atomic mass unit or less).

H. Optical features (i) Use of high efficiency gas In some embodiments, intensive delivery of the He gas to the tip 206 can increase the efficiency of use of the He gas within the microscope system 200. In general, unionized He gas atoms can enter the ion optical device 130 and increase the distribution width of ion energy in the ion beam 192. In addition, low-energy, unionized He gas atoms can participate in charge exchange interactions with high-energy He ions, and can increase the distribution width of ion energy in the ion beam 192.

Thus, in some embodiments, a gas delivery system can be designed to provide gas (eg, He gas) to the tip 186 of the gas field ion source 120 in a more targeted manner and is more efficient. Unused gas (eg, unionized He gas) can be removed from the system in a conventional manner. For example, FIG. 21 is a partial schematic of a gas electric field ion microscope including a gas source 110 and a vacuum pump 734. The gas source 110 includes a delivery tube 730 of length q and diameter n that terminates at the delivery nozzle 736, and the vacuum pump 734 includes an inlet 732. The nozzle 736 is installed at a distance g from the top 187 of the tip 186, and the inlet 732 is installed at a distance l from the top 187 of the tip 186.

In some embodiments, g can be 10 mm or less (eg, 9 mm or less, 8 mm or less, 7 mm or less). Generally, g is 3 mm or more (for example, 4 mm or more, 5 mm or more, 6 mm or more). For example, g can be 3 mm to 10 mm (for example, 4 mm to 9 mm, 5 mm to 8 mm).

In certain embodiments, l can be 100 mm or less (eg, 90 mm or less, 80 mm or less, 70 mm or less, 60 mm or less, 50 mm or less). Generally, l is 10 mm or more (for example, 20 mm or more, 30 mm or more, 40 mm or more). For example, l can be 10 mm to 100 mm (for example, 30 mm to 100 mm, 40 mm to 80 mm).

In some embodiments, the local pressure of the He gas at the position of the top 187 of the tip 186 is 10.^-5Torr or higher (eg 10^-4Torr and above, 10^-3Torr and above, 10^-2Torr and above, 10^-1Torr or higher, 1 Torr or higher). At the same time, the total pressure of He gas in the microscopy system can be reduced compared to systems using He gas background introduction. For example, the total He pressure of the microscope system 200 is 10^-4Below Torr (eg 10^-5Below Torr, 10^-6Below Torr, 10^-7Below Torr, 10^-8It can be Torr or less).

In some embodiments, the distance l and cross-sectional area of the inlet 732 are selected so that the vacuum pump 734 can capture unionized He atoms within the region of a particular solid angle of the microscope system 200. For example, for the He atom located at the top 187 of the tip 186, the solid angle ranged by the injection port 732 is 5 ° or more (for example, 10 ° or more, 15 ° or more, 20 ° or more, 30 ° or more, 40 °). Above).

In general, the ratio of the length q of the delivery tube 730 to the diameter n of the tube 730 can be selected to control the orbital distribution of the He gas atoms delivered to the tip 186. For example, in some embodiments, the q / n ratio is 3 or greater (eg, 4 or higher, 5 or higher, 6 or higher) and / or 10 or lower (eg, 9 or lower, 8 or lower, 7 or lower). Can be done. In certain embodiments, the q / n ratio can be 3-10 (eg, 3-9, 4-9, 4-8, 5-8, 5-7).

In some embodiments, the gas delivery system can include more than one delivery tube and delivery nozzle. For example, in certain embodiments, the gas delivery system can include two or more (eg, three or more, four or more, five or more, six or more) gas delivery tubes. Each of the plurality of gas delivery pipes can be arranged so that the He gas can be delivered so as to be relatively directed toward the tip 186. As a result of the use of multiple gas delivery tubes, the local pressure of He gas at the position of the top 187 of the tip 186 can be further increased. One or more vacuum pumps can be used to remove unionized He gas from the microscope system 200.

In some embodiments, the gas delivery tube 730 can be incorporated into other components of the system. For example, in certain embodiments, by one or more passages for gas delivery in the extractor 190 and / or suppressor 188 (eg, two or more passages, four or more passages, six or more passages). The gas delivery pipe 730 can be formed. In some embodiments, one or more passages for gas delivery (eg, two or more passages, four or more passages, 6) to the pillars supporting the tip 186 (eg, pillars 522a / b and 552). A passage more than a book) can be provided. As an example, in certain embodiments, the extraction unit 190 may include four passages for gas delivery to the tip 186. The passages can be arranged radially at equal intervals along the outer circumference of the extraction unit 190 so that the openings of each passage directly face the tip 186. The length-to-diameter ratio of each passage may be the same or different.

Many advantages can be realized by incorporating the gas delivery tube into the other elements of the microscope system 200. For example, the use of a metal tube 730 installed close to the tip for gas delivery may cause an electric field in the vicinity of the tip 186 to perturb. Incorporation of the gas delivery tube into other elements of the microscopy system can eliminate such perturbations. As another example, the spatial region in the vicinity of the tip 186 is generally congested with electrodes and other devices due to the operation of the microscope system 200. Incorporating the gas delivery tube 730 into other elements of the system can reduce congestion near the tip 186.

In some embodiments, the He gas delivered by the delivery tube 730 can be precooled to near the operating temperature of the tip 186 as it enters the microscope system 200. For example, a portion of the delivery pipe 730 can be placed in contact with a supply container for a coolant (eg, liquid nitrogen) used to cool the tip 186. As a result of this thermal contact, the He gas moving through the tube 730 is cooled to approximately the same temperature as the tip 186 prior to introduction into the chamber in which the tip 186 is located.

(ii) Neutralization of surface charge Generally, when He ions are incident on the surface of a sample, secondary electrons are emitted from the sample. Many of the secondary electrons leave the sample, resulting in a surface with a net positive charge. Excessive positive charge on the surface of the sample can cause many undesired effects. In some embodiments, the positive charge can damage the material of the sample. For example, certain substances may be charge sensitive and react violently (eg, explode) in the presence of excess positive (or negative) charge.

In certain embodiments, the positive charge on the sample surface may limit the ability of the detector to detect secondary electrons emitted from the sample by the interaction of the ion beam with the sample. For example, the attractive force of positive charges and secondary electrons on the sample surface can slow down the electrons and prevent them from reaching the detector.

In some embodiments, positive charging of the sample surface can lead to inaccurate ion beam rasterization. The deflection and deceleration of the incident ion beam as a result of the electric field formed by the positive charge on the sample surface can reduce the energy of the incident ion and change its trajectory in a way that is difficult to predict.

When the net positive charge on the sample surface is large enough, the surface of the sample may act as an electron microscope for the He ions that deflect the He ions before they reach the sample surface and separate them from the sample surface. is there.

The surface charging effect can be canceled by using a flood gun capable of sending an electron bundle to the sample surface. FIG. 22 shows a portion of a gas electric field ion microscope including a flood gun 840 configured to send an electron beam 842 to the surface 181 of the sample 180 when the He ion beam 192 is incident on the surface 181. In general, the electron flux on the surface 181 can be controlled so that the electron beam 842 can cancel the surface charging effect in a desired range.

FIG. 22 shows the ion beam 192 and the electron beam 842 colliding with the surface 181 of the sample 180 at the same time, but other approaches may be used. For example, the flood gun may be configured to send an electron beam 842 to the sample 180 prior to irradiating the surface 181 with the He ion beam 192 to form a charge layer 846 in the inner surface region of the sample 180. Yes (Fig. 23). Layer 846 has an average depth m below surface 181 and layer 846 has a thickness r measured perpendicular to surface 181. In general, the depth m and thickness r and the electron density of layer 846 depend on the electron energy in the electron beam 842, the angle of incidence of the electrons in the electron beam 842 on the surface 181 and the total dose of electrons sent to sample 180. Can be controlled.

In some embodiments, the average energy of the electrons in the electron beam 842 is adjustable when incident on surface 181. For example, the average electron energy can be 500 eV or more (for example, 1 keV or more, 2 keV or more) and / or 20 keV or less (for example, 15 keV or less, 10 keV or less). For example, when incident on the surface 181 the average energy of the electrons in the electron beam 842 can be 500 eV to 20 keV (for example, 1 keV to 15 keV, 2 keV to 10 keV).

The incident angle δ of the electrons in the electron beam 842 with respect to the surface 191 corresponds to the angle between the main orbit of the electron beam 842 and the perpendicular 848 of the surface 181. Generally, δ is 0 ° or more (for example, 10 ° or more, 20 ° or more) and / or 80 ° or less (for example, 70 ° or less, 60 ° or less). For example, δ can be 0 ° to 70 ° (for example, 0 ° to 10 °, 40 ° to 60 °).

In certain embodiments, the total electron current delivered to sample 180 is greater than or equal to 10 pA (eg, greater than or equal to 100 pA, greater than or equal to 1 nA, greater than or equal to 10 nA) and / or less than or equal to 100 μA (eg, less than or equal to 10 μA, 1 μA, less than 500 nA, 100 nA). Below). For example, the total electron current delivered to the sample 180 can be 10 pA to 1 μA (eg, 100 pA to 100 nA, 1 nA to 10 nA).

In some embodiments, m is greater than or equal to 10 nm (eg, greater than or equal to 25 nm, greater than or equal to 50 nm, greater than or equal to 75 nm, greater than or equal to 100 nm) and / or less than or equal to 500 nm (eg, greater than or equal to 400 nm, less than or equal to 300 nm, 200 nm). For example, m can be 10 nm to 500 nm (for example, 25 nm to 500 nm, 50 nm to 500 nm, 75 nm to 400 nm, 100 nm to 400 nm).

In certain embodiments, multiple flood guns can be used. For example, in some embodiments, multiple flood guns can be used to irradiate different positions on the surface 181 of sample 180 with electrons. In certain embodiments, each flood gun can be used to irradiate the same portion of surface 181 with electrons. Optionally, different flood guns can be activated at different times. For example, one or more flood guns can be used to irradiate surface 181 with electrons before irradiating surface 181 with He ions (eg, forming a charge layer on the inner surface), but one or more. A flood gun can also be used to irradiate the surface 181 with electrons while the surface 181 is being irradiated with He ions. In some embodiments, all flood guns can be used to irradiate the surface 181 with electrons before irradiating the surface 181 with He ions (eg, forming a charge layer on the inner surface). In certain embodiments, all flood guns can also be used to irradiate the surface 181 with electrons while the surface 181 is being irradiated with He ions. Moreover, other combinations may be used.

Although embodiments have been described in which surface charge neutralization can be achieved using a flood gun, the emitted secondary electrons are collected and returned to the sample surface to reduce the net positive charge on the surface. It is also possible to achieve neutralization of the surface charge by using a collecting electrode. Referring to FIG. 24, the collector electrode 852 is connected to the sample 180 by the conductor 854. When the sample 180 is irradiated with the He ion beam 192, secondary electrons (indicated by the arrow 856) emitted from the surface 181 of the sample 180 are incident on the collector electrode 852. Next, the electron 856 is returned to the surface 181 by the conductor 854 to reduce the positive charge on the surface 181. An additional collector electrode 852 can be connected to sample 180 to provide further surface charge neutralization.

In certain embodiments, one or more collector electrodes and one or more flood guns can be used in combination. For example, one or more flood guns can be used to irradiate surface 181 of sample 180 with electrons (eg, form a charge layer on the inner surface) before irradiating surface 181 with He ions. By using one or more collector electrodes, the charge on the surface 181 can be neutralized while the surface 181 is irradiated with He ions. Also, other combinations are possible.

In some embodiments, the flood gun 840 can be configured to deliver a very low energy electron beam 842 to sample 180. For example, the electrons in the beam 842 can have an average energy of about 50 eV or less. Low energy electrons have low landing energy, which limits the amount of negative charge that can be stored on surface 181. For example, if the average electron energy in the electron beam 842 is 50 eV and the sample 180 is charged to a potential of -50 V with respect to the common ground, the electrons from the flood gun 840 will no longer land on the surface of the sample. .. As a result, the maximum stored negative charge on the surface 181 of the sample 180 can be controlled by adjusting the energy of the low energy electrons from the flood gun 840. This method can be used to image a non-conductive material without depositing a layer of the conductive material on top of the non-conductive material to prevent charging of the non-conductive material. Figure 25 shows an example of this method. The ion beam 192 is incident on the surface 181 of the sample 180, which is a dielectric with a relatively low conductivity (for example, the sample 180 is not a metal). The sample manipulator 140 supports the sample 180, where the sample manipulator 140 is biased to a potential of -600 V with respect to the common external ground of the microscope system 200. The potential applied to the manipulator 140 forms an electric field on the surface 181 of the sample 180. The flood gun 840 is configured to emit an electron beam containing electrons having an average energy of 500 eV to the surface 181 near the collision ion beam 192. First, the electric field on the surface 181 due to the bias applied to the manipulator 140 causes the deflection of the electrons from the flood gun 840 along the orbits such as 843a and 843b (the electrons do not land on the surface 182). However, as the positive charge accumulates on the surface due to the incident He ions, the sample 180 is positively charged, reducing the electric field strength received by the electrons from the flood gun 840. Surface of sample 180 181 When the charge of is accumulated at the point where the effective bias on the surface reaches -500V with respect to the common grounding part, the electrons from the flood gun 840 can land on the surface 181 following the orbit such as 343c, and the surface. The positive charge above can be neutralized. As a result, the accumulation of positive charges on the sample 180 can be controlled by controlling the bias applied to the manipulator 140 and the energy of the electrons sent by the flood gun 840. Therefore, the sample 180, which is a non-conductive substance, can be imaged without accumulating surface charge, otherwise the voltage contrast effect resulting in surface charge can lead to undesired image contrast. Images of non-conductive materials and semiconductor materials can be obtained without depositing a layer of conductive material that functions as a charge dissipating layer on the sample.

In some embodiments, the flood gun can be configured to send electrons to sample 180, which has negative landing energy, i.e., if the electrons lack a positive charge on the sample surface, the electrons will be on sample 181. Does not land at all. When sample 180 gains surface charge from incident He ions, the electrons from the flood gun 840 begin to land and neutralize the positive charge. As a result, the surface 181 of sample 180 remains largely uncharged.

In some embodiments, the conversion surface can be used to generate secondary electrons, which can then be used to neutralize the positive charges that accumulate on the surface 181 of the sample 180. it can. For example, a conversion surface formed of a substance with a high secondary electron emission (for example, platinum) can be placed close to the sample 180. High-energy He ions and / or neutral atoms from sample 180 can hit the conversion surface and generate secondary electrons. The generated secondary electrons are attracted by the positive surface charge accumulated on the sample 180. As a result, the secondary electrons land on the sample surface, neutralize the positive charge, and reduce the electric field due to the surface charge. Therefore, if the surface positive charge is accumulated a lot, the secondary electrons are strongly attracted to the surface 181 of the sample 180. This provides a self-regulating mechanism for reducing surface charge.

In some embodiments, the conversion plate can be attached directly to one element of the ion optics 130 to provide secondary electrons for neutralizing the surface charge of sample 180. For example, in FIG. 26, the conversion plate 845 is attached to the surface of the second lens 226. The electron 842 from the flood gun 840 is directed to enter a conversion plate formed from a material with a high secondary electron emission. A He ion beam 192 is incident on the surface 181 of the sample 180, and as time passes, a positive charge is accumulated on the surface 181 of the region where the ion beam 192 is incident. Secondary electrons 847 generated from the conversion plate 845 are attracted to surface regions having excess positive charges and land in those regions to neutralize the excess positive charges. After removing the excess surface charge, no more secondary electrons land on the surface 181. As a result, the surface can be maintained in a quasi-neutral state.

In general, a flood gun 840 can be configured for continuous or intermittent operation. In particular, during intermittent operation, the flood gun 840 can be turned on and off at the desired speed. For example, in some embodiments, the flood gun 840 can be switched to provide charge neutralization of sample 180 at a certain pixel emissivity. The ion beam 192 can be rasterized in a discontinuous step over the surface of the sample 180 to irradiate a continuous portion of the sample surface. After irradiating each portion, the flood gun 840 can be used to neutralize the surface charge in the irradiated area. This corresponds to charge neutralization at a certain pixel emissivity. Alternatively or additionally, using a flood gun 840 (eg, after irradiating the entire line of the discontinuity of sample 180 with an ion beam 192) and / or (eg, discontinuity of sample 180) at a certain line scan rate. Neutralization can be performed at a certain frame rate (after irradiating the entire two-dimensional region of the portion with the ion beam 192).

In some embodiments, a flood gun 840 can be used to improve the ease of detection of secondary electrons from sample 180. For example, a flood gun 840 can be used to incorporate a layer of charge (eg, charge layer 846) within the bulk region of sample 180. The incorporated negatively charged layer induces an electric field on the surface 181 of sample 180. The secondary electrons emitted from the sample 180 due to the interaction between the sample 180 and the incident ion beam 192 are accelerated by the electric field formed by the charge layer 846 and separated from the sample 180, and the secondary electrons generated by the properly configured detector Makes detection relatively easy.

In FIGS. 27A and 27B, an example of the use of the built-in negative charge layer is shown graphically. In FIG. 27A, the ion beam 192 is incident on the surface 181 of the sample 180. A large number of secondary electrons 2012 are generated within the first few nanometers of sample 180. Initially, many secondary electrons escape as free electrons 2014, which can be detected by a well-configured detector. However, over time, the incident He ions are embedded in the sample 180, forming a positively charged layer 2010 in the sample 180. As the net positive charge in layer 2010 increases, secondary electrons 2012 are gradually attracted toward layer 2010, and less secondary electrons 2012 escape from sample 180 as free electrons 2014. As a result, imaging samples by detecting secondary electrons can become increasingly difficult.

The solution to this problem is shown in Figure 27B. In the embodiment shown in FIG. 27B, a flood gun 840 (not shown) is used to incorporate a layer of negative charges (eg, electrons) 2016 inside the sample. The built-in negative charge layer is similar to layer 846 shown in FIG. As a result of layer 2016, the secondary electrons 2012 generated in sample 180 are accelerated away from sample 180, resulting in an increase in the number of generated secondary electrons 2014 exiting sample 180, resulting in detection secondary from sample. Strengthen the electronic signal. In effect, Layer 2016 acts as an electrostatic mirror for secondary electrons, improving its detectability.

In general, prior to sample analysis, electrons can be embedded in the sample using the flood gun 840 and / or electrons can be embedded in the sample while imaging the sample using the flood gun 840. In some embodiments, the sample can be irradiated with electrons from the flood gun 840 at intervals (eg, at regular intervals). This can help, for example, to keep the level of charge relatively constant. For example, the sample can be irradiated with electrons from the flood gun 840 at a time cycle corresponding to the residence time per pixel (for example, 100 ns).

(iii) Vibration division Mechanical vibrations due to vacuum pumps, various moving parts and background acoustic disturbances affect certain performance parameters of the gas field ion microscope system 200 (eg, image resolution, ion beam spot size on sample 180, stability). In some cases. In some embodiments, the sample manipulator 140 can be configured to separate the sample 180 from the other components of the system 200, thereby reducing the effects of external mechanical disturbances. FIG. 28 shows a vibration-partitioned sample manipulator 140 that includes an induction needle 906 supported by an actuating device 908, wherein the needle 906 and the actuating device 908 are each placed in a sample table 904. The support disc 902 is located on the sample table 904, and the friction spider 900 that supports the sample 180 is mounted on the disc.

To move the sample 180 in the xy plane, the actuator 908 receives a suitable signal from the electronic control system 170 and activates the guide needle 906. The guide needle 906 pierces the sample 180 and / or the spider 900 in response to a signal from the actuator 908, resulting in translation in the xy plane.

The width j of the guide needle 906 at its apex is generally chosen to be slightly smaller than the diameter b of the gap 910 within the spider 900. For example, j can be 1 mm and b can be 1.1 mm. In addition, the spider 900 and disc 902 are selected to increase the static friction force between the disc 902 and the spider 900, which can be overcome by the force applied to the sample 180 by the actuator 908 through the guide needle 906. it can. The guide needle 906 is formed of a mechanically adapted material that deforms under load stress and can reduce the transmission of vibrations to the sample 180, but is sufficient to transfer the force applied by the actuator 908 to the sample 180. Hardness.

As a result of these system parameters, the mechanical vibrations coupled in the sample table 904 can be partially absorbed and dispersed by the guide needle 906, resulting in little or no vibration of the spider 900. Absent. Further, when the guide needle 906 exerts a force on the spider 900, the guide needle 906 preferentially slips with respect to the side surface of the spider 900, rather than inducing vibration of the spider 900.

In some embodiments, the guide needle 906 can have a substantially rectangular cross-sectional shape. The rectangular cross-sectional shape can help ensure that no rotation of the sample 180 and / or rotation of the spider 900 occurs, as the guide needle 906 translates the spider 900 in the x and / or y directions. .. When tilting the sample manipulator 140 with respect to the axis 132 of the ion optics 130 (for example, to irradiate the sample 180 with an ion beam 192 at a non-vertical angle), the material used to form the spider 900 and / or the disc 902 should be used. It can be selected so that there is a higher static friction force between these elements. Alternatively or additionally, in certain embodiments, the spider 900 and the disc 902 can be magnetically coupled to increase the frictional force between the elements. The coupling of the magnetic fields may be done with caution to ensure that the magnetic fields are localized and do not disturb the sample 180 or the collision ion beam 192.

When the needle 906 does not work, the guide needle 906 can be completely separated from the spider 900. For example, after the guide needle 906 exerts a force on the spider 900 to translate the spider 900 and the sample 180 in the xy plane, the electronic control system 170 can generate a small recoil motion of the needle 906, the guide needle 906. Introduce a space between and Spider 900. As a result, the induction needle 906 is completely separated from the spider 900 to prevent the needle 906 from coupling mechanical vibrations to the spider 900.

FIG. 29 represents a sample holding assembly 1510 for a microscope system. The sample holding assembly 1510 helps reduce the use of bearings and reduce low frequency mechanical vibrations in the sample during operation. The assembly 1510 includes a body portion 1511 having an opening 1512 for containing a sample. The body 1511 is connected to the arm 1518 by an adjustable connector 1522. The arm portion 1518 uses the grip portion 1520 to support the sample table 1514. The sample table 1514 includes a surface disk 1516 having an opening 1524.

The assembly 1510 can be connected to the ion microscope so that the tip 186 points in the direction of the opening 1524 on the sample table 1514. The body portion 1511 can be formed from suitable hard materials such as hardened steel, stainless steel, phosphor bronze and titanium. The body portion 1511 can be sized and shaped to meet specific application needs. As an example, the size and shape of the body 1511 can be selected for use with the microscope system disclosed in the present application. During operation, the sample can be introduced into the assembly 1510 through the opening 1512.

The sample table 1514 is supported by an arm 1518 that connects to the body 1511 along the adjustable connector 1522. The adjustable connector 1522 allows the arm 1518 to move up and down. The arm portion 1518 and the sample base 1514 can be moved in the vertical direction and fixed at a specific position. The connector 1522 can be controlled by air or vacuum, so that the arm 1518 and the base 1514 can be firmly secured in the desired vertical position. Connector 1522 can optionally include other types of connectors.

The sample table 1514 is connected to the arm portion 1518 by using the grip portion 1520. The arm portion 1518 can have a shaft portion that extends inward, so that the grip portion 1520 of the sample table 1514 can fasten the shaft portion. The base 1514 can be tilted by operating the grip portion 1520 pneumatically or in a vacuum. By controlling the grip portion 1520, the base 1514 can be tilted to a desired position. In some embodiments, the sample table 1514 can be firmly fixed in the desired tilted position by tightening the grip portion 1520 after reaching the desired position.

Further, the sample table 1514 includes a surface disk 1516 having an opening 1524. The sample may be placed on the disk 1516, and a sample position control system can be introduced through the opening 1524 to move the sample on the plane of the disk 1516. In certain embodiments, the disc 1514 can rotate around its center to rotate and move the sample placed on the surface of the disc as desired. The disc 1516 can be formed from suitable hard materials including ceramics, glass and polymers.

FIG. 30 represents a sample holding assembly for a microscope system. The sample holding assembly of FIG. 30 is similar to the sample holding assembly of FIG. 29 having a spider 1600 placed on the surface of the disc 1516. The Spider 1600 can have legs to place it on top of the opening 1524. Optionally, the spider 1600 can have an opening in a portion of the surface. Spider 1600 can be formed from suitable hard materials including ceramics, glass and polymers.

When the microscope system 200 is activated, the sample 180 can be moved, tilted, translated in the xy plane, and rotated. If the sample 180 is tilted and its tilt angle (eg, the angle between the ion beam 192 and the surface normal of the sample 180) is relatively large, the tilted sample will be in focus over the entire field of view of the microscope system 200. There is a risk that it will not be. As a result, the image of the sample obtained under that condition may be out of focus and blurred in the region outside its center and perpendicular to the axis of inclination.

They can be corrected by changing the focal length of the lens 226 while scanning the ion beam 192 over the surface of the sample 180. To make this correction, the sample manipulator 140 can transmit the tilt angle information of the sample 180 to the electronic control system 170. Alternatively, the tilt angle information can be manually entered by the system operator through the user interface. The electronic control system 170 determines a series of voltage corrections to be applied to the second lens 226 based on the orientation of the sample 180 and scans the ion beam 192 over the tilted surface of the sample 180 to determine the focal length of the lens 226. It can be changed dynamically.

In addition, the lateral dimension of the tilted sample is distorted by the projection of the tilted sample on a flat surface and the difference in distance to the ion optics 130. For example, the lateral dimension of the slanted sample surface is simply believed to be due to the actual orientation of the sample with respect to the ion beam 192. Another example is trapezoidal distortion of an image. The effect is that the rectangular image appears to be a keystone in its shape as a result of distorting the features of the rectangle.

They can be corrected by adjusting the scanning amplitudes of the scanning deflectors 219 and 221 while scanning the ion beam 192 over the surface of the sample 180. To make this correction, the electronic control system 170 can obtain information about the tilt angle of the sample 180 in the same way as described above. The electronic control system 170 determines the adjustment of the scan amplitude applied to the scan deflectors 219 and 221 based on the tilt of the sample 180, and because of the undistorted image of the tilted sample 180 surface, the tilted sample 180 surface. The deflection of the ion beam can be adjusted while scanning the ion beam 192. Alternatively, these two distortion effects can be corrected by digitally manipulating the distorted image.

(iv) Reduction of the presence of neutral particles and double-charged ions in the ion beam As described above, neutral particles (eg, He atoms) can enter the ion optical instrument 130 of the microscope system 200 as unionized neutral atoms from the gas field ion source 120. Such neutral particles can adversely affect the performance of the microscopy system. Therefore, in some embodiments, it is preferable to reduce the presence of neutral particles in the ion beam 192. Also, divalent He ions (eg He)²⁺) Can be generated in the gas field ion source 120 by double ionization of He atoms in the vicinity of the tip 186 or by collision between He ions. The focusing properties of divalent He ions are different from monovalent ions, and the divalent ions present in the ion beam 192 can result in large spot sizes on sample 180 and other undesired effects.

One approach to reducing the population of neutral particles in the ion beam 192 involves reducing the likelihood that the neutral particles will enter the ion beam. Such an approach can include, for example, using gas delivery directed at the tip 186 (see description above) to reduce the total presence of unionized He atoms in the microscopy system 200.

Other approaches to reducing the number of neutral particles in the ion beam 192 include removing the neutral particles from the ion beam after they are present in the ion beam 192. This approach can include the use of electrostatic lens devices to deflect ions, spatially separating ions and neutrals within the ion optics 130. For example, FIG. 31 shows an ion optics 130 in which the deflector 220 is offset from the longitudinal axis 132 of the ion optics 130 and an additional deflector 223 is located. The He ion beam 192 contains a He ion 192a and a He atom 192b. In order to separate the He ion 192a and the He atom 192b, the potential applied to the deflector 223 is adjusted to cause the He ion 192a to be deflected in the x direction. He atom 192b is unbiased because it is unaffected by deflector 223. The He atom 192b is substantially captured by the collector 1016, preventing the He atom 192b from passing through the aperture 224. Further, as a result of adjusting the potential applied to the deflectors 220 and 222, the trajectory of the He ion 192a is realigned with the longitudinal axis 132, a part of the He ion 192a passes through the throttle 224, and the ion beam 192. As incident on the surface 181 of the sample 180.

In addition, other techniques can be used to remove neutral particles from the ion beam. In general, such techniques include deflecting ions in an ion beam using an electric and / or magnetic field without deflecting the neutral particles. In some embodiments, a combination of electric and magnetic fields can be used to compensate for the spatial separation of energy-dependent ions that results in ion deflection within the ion optics 130. In addition, various asymmetric ion barrel shapes (eg, curved ion barrels) can be used to separate He atoms and ions.

For example, in FIG. 32, a He atom, a monovalent He ion, and a divalent He ion can be separated by using the curved lens barrel configuration of the ion optical device 130. The ion beam 192 enters the ion optical device 130 and propagates in a direction inclined with respect to the axis 132 of the ion optical device 130. The ion beam 192 is a neutral He atom, He.⁺Ion and He²⁺Contains ions. The potential is applied to the deflector 223 and He in the ion beam 192⁺To deflect the ions, after passing through the deflector 223, as an ion beam 192a, He⁺Ions propagate along axis 132. However, the neutral atom is not deflected as it passes through the deflector 223. Therefore, the neutral atom is He⁺It provides a neutral atom beam 192b that is spatially separated from the ions and captured by collector 1016b. He²⁺Ion is He⁺It is deflected to a greater extent than the ions, spatially separating monovalent and divalent ions into He.²⁺An ion beam 192c of ions is provided. He²⁺Ion beam is captured by collector 1016c. As a result, the ion beam 192a exiting the ion optics 130 is substantially He.⁺Contains only ions.

Figure 33 shows the He atom and He.⁺Ion and He²⁺Other embodiments of an ion optical system for separating ions are shown. The ionic optical system shown in FIG. 33 includes a continuous electric field and magnetic field without dispersion, and the electric and magnetic fields are He atoms, He.⁺Ion and He²⁺It is used to separate ions from each other and has no prismatic effect on the particle beam. The ion optics system includes a set of three deflectors 223a, 223b and 223c, the deflectors He through the ion optics 130.⁺It is configured to deflect and orient the ions, resulting in virtually He.⁺The ion beam 192 containing only ions escapes from the ion optical device 130. The neutral atom beam 192b is not deflected and is captured by collector 1016b at a position following each deflector. Divalent He ion is He⁺More polarized than ions, multiple Hes²⁺Beam 192c is captured by collector 1016c. As a result, He atom, He⁺Ion and He²⁺He spatially separates the ions from each other, blocking unwanted beam components within the ion optics 130 as the ion beam 192.⁺Aim the ions at sample 180.

In some embodiments, the use of a magnetic field can result in spatial separation of the orbits of the ions in the ion beam 192, which have the same charge but correspond to the different isotopes of the gas introduced by the gas source 110. it can. For certain gases such as He, which have spontaneous and dominant isotopes (eg, relative abundance greater than 90%), the magnetic field separation effect is generally small. However, this effect may be significant for other gases that have two or more spontaneous isotopes and no dominant isotope. As a result, in certain embodiments, isotope separators (eg, blocks used to prevent unwanted isotopes from exceeding the length of the ionic optics 130) can be used. In some embodiments, collector 1016, which is used to block neutral atoms or divalent ions, can also be used to block unwanted isotopes in the ion beam 192.

<u style="single">Particle type</u> The interaction of the ion beam with the sample allows different types of particles to emerge from the surface due to various interactions, as described below. Examples of such particles include secondary electrons, Auger electrons, scattered ions, primary neutral particles, X-ray photons, IR photons, visible photons, UV photons, secondary ions and secondary neutral particles. One or more particles can be detected and analyzed to determine one or more different information about a sample. The types of information about such a sample include topography information about the sample surface, substance composition information about the sample surface, substance composition information about the inner layer surface region of the sample, crystal information about the sample, and voltage contrast about the sample. Information, voltage contrast information about the inner layer region of the sample, magnetic information about the sample, and optical information about the sample can be mentioned. As used herein, sample surface terminology refers to volumes up to a depth of 5 nm.

A. Secondary electrons Secondary electrons are electrons emitted from a sample species having an energy of less than 50 eV, as referred to herein. In general, secondary electrons are emitted from the sample surface at a certain angle and energy. However, the most interesting information is usually (energy-resolved secondary electron information or angular-resolved secondary) because the total abundance of secondary electrons can provide information about the sample surface, as described below. The total abundance of secondary electrons (as opposed to electronic information).

Secondary electrons can be detected using one or more suitable detectors capable of detecting electrons (see above for detectors). When a plurality of detectors are used, all of the detectors may be of the same type or different types of detectors, and can usually be configured as desired. .. The detector should detect electrons emitted from the surface 181 of sample 180 (the surface on which the ion beam collides), the surface 183 of sample 180 (the surface opposite the surface where the ion beam collides), or both. It can be configured (see above for detector configuration).

The detected secondary electron signal can be used to form an image of the sample. In general, an ion beam is rasterly scanned over the field of view of the sample surface, and one or more detectors measure the secondary electron signals (corresponding to individual pixels in the image) at each raster stage. Normally, each detector remains in a fixed position with respect to the sample when rasterly scanning the ion beam over the field of view of the sample surface. However, in certain embodiments, one or more detectors can be moved relative to the sample. For example, when using a single detector, moving the detector relative to the sample can provide angle-dependent information about the sample.

In certain embodiments, detecting the total abundance of secondary electrons can provide information about the topography of the sample. The total abundance of secondary electrons at a given position on the surface is usually determined by the slope of the surface with respect to the ion beam at that point. In general, the higher the inclination of the surface with respect to the ion beam (that is, the larger the incident angle of the ion beam measured from the normal of the surface), the higher the total abundance of secondary electrons. Therefore, the change in the total abundance of secondary electrons depending on the position of the ion beam on the sample surface can be associated with the change in the surface inclination, and provides information on the topography of the sample surface.

In some embodiments, the total abundance of secondary electrons can be detected to obtain material composition information about the sample (eg, component information, chemical environment information). In such embodiments, the information is primarily about the surface of the sample. In general, each element or substance in a given chemical environment will have a specific amount of secondary electron emission. As a result, the total abundance of secondary electrons at a given position on the surface is usually determined by the material present at that position. Therefore, the change in the total abundance of secondary electrons depending on the position of the ion beam on the sample surface can be associated with the change in one or more elements and / or one or more substances present on the sample surface. It can provide material composition information about the sample surface. In certain embodiments, specific substances in the sample can be identified based on quantitative measurements of secondary electron emission from the sample. For example, substances such as Al, Si, Ti, Fe, Ni, Pt, and Au have known secondary electrons when irradiated with He ions under controlled conditions. Based on the known secondary electron emission of various substances, an ion microscope (for example, a gas electric field ion microscope) can be calibrated to identify the presence or relative abundance of a wide variety of substances in the sample under study. For example, Table 1 shows the amount of secondary electrons released for various substances. The amount of emission was measured with an average ion energy of 21 keV at the normal incidence of the He ion beam. For example, for non-vertical incident angles, the emission amount shown in Table 1 is generally scaled by a multiple factor corresponding to the secant line of the incident angle on the sample surface of the ion beam. Other experimental conditions will be described in the corresponding examples described below.

<tables num="1"><img file="JP2009517841A_D0005.tif" /></tables>

In certain embodiments, voltage contrast information can be obtained by detecting the total abundance of secondary electrons, which in turn provide information on the conductive properties of the sample surface and / or the potential of the element and / or the potential of the substance. Can be provided. The total abundance of secondary electrons at a given position on the sample surface is usually determined by the electrical properties of the material present on the sample surface. In general, a substance having low conductivity tends to be positively charged with time when irradiating an ion beam, while a substance having high conductivity tends to be positively charged with time when irradiating an ion beam. Low. Thus, for example, the total abundance of secondary electrons at a given position on the sample surface tends to decrease over time (due to large surface charges resulting in few electrons escaping from the sample) for materials with low conductivity. However, the total abundance of secondary electrons at a predetermined position on the highly conductive sample surface tends to receive almost no decrease in the total abundance of secondary electrons over time (due to small surface charge). is there. As a result, the change in the total abundance of secondary electrons depending on the ion beam position on the sample surface can be associated with the conductivity of the substance at that position, providing voltage contrast information about the sample surface.

The He ions embedded in the inner layer surface region of the sample can provide a voltage contrast effect on the inner layer surface. As described in relation to FIGS. 27A and 27B, the He ions on the inner layer surface can prevent secondary electrons generated from the sample from escaping from the sample surface. Therefore, the contrast of the secondary electron image of the sample can be due to the charging of the inner layer surface of the sample by the incident He ions.

The information provided by these techniques can be used for ion beam testing of semiconductor products. For example, using voltage contrast measurements, whether parts of electrical equipment and / or electrical circuits have different potentials when irradiated with an ion beam due to the presence or absence of electrical connections in that part, and Therefore, it can be determined whether the device and / or the circuit is operating correctly.

In some embodiments, detecting the total abundance of secondary electrons can provide crystal information about the sample. The total abundance of secondary electrons can be changed depending on whether the ion beam is aligned with the crystal structure of the sample (for example, whether it is aligned along one of the unit vectors representing the crystal lattice). .. When the ion beam is aligned with the crystal structure of the sample, the ions in the ion beam may enter a predetermined distance in the sample without colliding with the sample atoms (usually called channeling). Is relatively high, and the total abundance of secondary electrons is low. On the other hand, when the ion beam is not aligned with the crystal structure, the possibility that the ions in the ion beam at that time enter a predetermined distance without colliding with the sample atom is reduced, and the abundance of secondary electrons is reduced. Is high. Therefore, the change in the total abundance of secondary electrons according to the ion beam position on the sample surface can be associated with the crystal information of the substance at that position. For example, there may be regions on the sample surface where the total abundance of secondary electrons is substantially the same. For example, such regions can have the same crystal orientation, where the size of the region is the size of the particles (eg, in a polycrystalline sample containing multiple oriented crystal domains) and / or the size of the crystals. And / or the magnitude of the total abundance of secondary electrons for a substance of a given chemical composition (eg, elemental composition, substance composition) can be determined by the strain of the substance. Information about the distorted region of the sample (whether amorphous or crystalline) can be provided.

In certain embodiments, detecting the total abundance of secondary electrons can provide magnetic information about the sample. The total abundance of secondary electrons can be determined by the magnitude of the magnetic field near the sample surface. In some embodiments, for example, the magnetic field in the vicinity of the sample surface can be altered by the magnetic domain within the sample that creates the local magnetic field at the sample surface. In certain embodiments, a static magnetic field is applied by an external magnetic field source and the magnetic domain within the sample creates a local magnetic field on the sample surface that introduces changes in the applied external magnetic field. In any case, changes in the local magnetic field on the sample surface can, for example, change the orbits of secondary electrons emitted from the sample. A change in the orbit of secondary electrons can correspond to an increase in the total abundance of secondary electrons as the orbit of the secondary electrons is changed so that more secondary electrons are directed toward one or more detectors. A change in the orbit of secondary electrons is equivalent to a decrease in the total abundance of secondary electrons as the orbit of secondary electrons is changed to move more secondary electrons away from one or more detectors. can do.

For some samples, the contrast appearing in the image of the secondary electrons of the sample may be due to two or more of the above mechanisms. In other words, images of secondary electrons of a particular sample show, in part, contrast due to changes in topography on the sample surface, changes in the material composition of the sample surface, crystal changes on the sample surface, and / or magnetic changes on the sample surface. Can include. Therefore, the information obtained from the measurement of the total abundance of secondary electrons can be combined with the information obtained from the measurement of other types of particles to qualitatively and / or quantitatively contribute from one or more of those mechanisms. It may be advantageous to separate into. This possibility will be described in detail below.

Secondary electron imaging techniques can be applied to a wide variety of samples. An example of such a type of substance is, for example, a semiconductor product such as a pattern forming wafer that can contain a plurality of conductors surrounded by a matrix-like insulator. Secondary electron imaging techniques can be used to identify equipment defects such as incomplete electrical connections between conductors and / or electrical short circuits between circuit elements. In general, secondary electron imaging techniques can be used for a wide range of ion beam test applications on semiconductor products. Optionally, this approach can be used for mask repair purposes as well.

Other examples of sample types for which secondary electron imaging techniques can be used are metals and alloys. For example, the surface distribution of each substance in the sample can be determined by using an image of a sample containing a mixed substance such as an alloy. A further example of sample types for which secondary electron imaging techniques can be used is a read / write structure for data storage. Additional examples of the types of substances for which secondary electron imaging techniques can be used are biological and pharmaceutical substances.

Imaging of a sample using secondary electrons generated by irradiation with a He ion beam can provide many advantages over imaging of secondary electrons through other techniques such as SEM. For example, the spot size of the He ion beam on the sample can be smaller than the spot size of the electron beam from the SEM. As a result of its small spot size, the area of the sample irradiated with the He ion beam is carefully controlled compared to the area irradiated by the SEM.

Moreover, since He ions are generally heavier than electrons, the scattering phenomenon does not disperse He ions as easily as scattering electrons in a sample. As a result, He ions incident on the sample surface can interact with the sample with a smaller amount of interaction than the electrons in the SEM. As a result, the secondary electrons detected by a gas field ion microscope (eg, He ion microscope) can be generated from a region smaller than the region where secondary electrons are generated in an SEM having a similar spot size. Therefore, the secondary electrons generated by the He ion beam correspond to more local inquiries on the sample surface (for example, when there is no lateral averaging of the material properties) compared to the secondary electrons generated by the SEM. be able to.

In addition, the He ion source can also provide a greater depth of focus than the electron source. As a result, the image of the sample obtained using an ion microscope (eg, gas field ion microscope) is a sample compared to the comparative image obtained from secondary electrons in SEM when measured along the direction perpendicular to the sample surface. Most of the can be clearly shown.

Also, there is a wider range of different substances available when interacting with the ion beam sample to eject secondary electrons from the sample than when interacting with the electron beam sample to eject secondary electrons from the surface. Due to the amount of secondary electron emission, the He ion beam can provide a sensitive contrast mechanism for the secondary electron image of the sample. In general, the amount of secondary electrons emitted from ordinary materials such as semiconductors and metals varies from 0.5 to 2.5 with an incident electron beam. However, the amount of secondary electrons emitted from the same substance irradiated with the He ion beam can vary from 0.5 to 8. Therefore, a gas field ion microscope (eg, a He ion microscope) can be used to identify different substances from secondary electron images more accurately than comparable SEM systems.

B. Auger Electronics As referred to in the present application, Auger electrons are electrons generated as shown below. The inner-shell atomic electrons are removed to form vacancies, which are then filled with secondary intraatomic electrons from the outer shell, and energy is released. This energy is emitted by another electron called the Auger electron. Generally, Auger electrons are emitted from the sample surface within a certain angle and energy range. However, the most interesting information is usually Auger (as opposed to angle-resolved Auger electron information), as the energy of the Auger electrons can provide information about the sample surface, as explained below. It is the energy of electrons. Auger electrons can be detected using one or more suitable detectors capable of detecting electrons by energy decomposition (see above for the type of detector). When a plurality of detectors are used, all of the detectors may be of the same type or different types of detectors, and can usually be configured as desired. A detector is used to detect Auger electrons emitted from the surface 181 of sample 180 (the surface on which the ion beam collides), the surface 183 of sample 180 (the surface opposite to where the ion beam collides), or both. It can be configured (see above for detector configuration). In order to increase the signal-to-noise of the Auger electrons to be detected, it may be preferable to use a detector capable of collecting Auger electrons having a relatively large solid angle. In addition or instead, an electron-collecting optical instrument (eg, an electrostatic lens system) that is adjacent to the surface of the sample and capable of directing electrons to the detector can be used (eg, the effectiveness of the detector for Auger electrons). Increase the solid angle).

In general, by detecting the energy of Auger electrons, it is possible to obtain substance composition information (for example, elemental information, chemical environment information) about a sample. In such embodiments, the information is primarily associated with the surface of the sample. In general, for each element or substance in a given chemical environment, the Auger electrons emitted by the element or substance will have a specific energy or energy band. As a result, the energy of an Auger electron at a given position on the surface is usually determined by the material present at that position. Therefore, the change in Auger electron energy depending on the position of the ion beam on the surface of the sample can be associated with the change in one or more elements and / or one or more substances present on the surface of the sample. , Provides material composition information about the sample surface.

Auger electronic imaging techniques can be applied to a wide variety of samples. An example of such a type of material is, for example, a semiconductor product such as a pattern forming wafer that can include a plurality of conductors surrounded by a matrix-like insulator. Optionally, this approach can be used for mask repair purposes as well. Other examples of sample types for which Auger electronic imaging techniques can be used are metals and alloys. For example, the surface distribution of each substance in the sample can be determined by using an image of a sample containing a mixed substance such as an alloy. A further example of sample types for which Auger electronic imaging techniques can be used is a read / write structure for data storage. Additional examples of the types of substances for which Auger electronic imaging technology can be used are biological and pharmaceutical substances.

Imaging a sample using Auger electrons emitted from the surface by the interaction of the sample with a He ion beam can provide many advantages over Auger electron imaging through other techniques such as SEM. For example, the spot size of the He ion beam on the sample can be smaller than the spot size of the electron beam from the SEM. As a result of its small spot size, the area of the sample irradiated with the He ion beam is carefully controlled compared to the area irradiated by the SEM.

Moreover, since He ions are generally heavier than electrons, the scattering phenomenon does not disperse He ions as easily as scattering electrons in a sample. As a result, He ions incident on the sample surface can interact with the sample with a smaller amount of interaction than the electrons in the SEM. As a result, Auger electrons detected by a gas field ion microscope (eg, He ion microscope) can be generated from a region smaller than the region where Auger electrons are generated in SEMs with similar spot sizes. For this reason, Auger electrons emitted from the surface due to the interaction between the sample and the He ion beam do not have a more local inquiry (for example, lateral averaging of material properties) on the sample surface than Auger electrons generated by SEM. If) can be accommodated.

In addition, the He ion source can also provide a greater depth of focus than the electron source. As a result, the image of the sample obtained using an ion microscope (eg, a gas field ion microscope), when measured along the direction perpendicular to the sample surface, is compared to the comparative image obtained from Auger electrons in SEM. Most can be clearly shown.

Another advantage of using an ion beam for the detection of Auger electrons, as opposed to an electron beam, is that when using an electron beam, Auger electrons are detected on the baseline of backward scattered electrons, but the ion beam. In use, there are no backscattered electrons. As a result, it may be possible to obtain a relatively high signal-to-noise ratio for Auger electrons detected while collecting a relatively small number of Auger electrons, and a relatively good Auger from the sample when using an ion beam. The time required to obtain the electron spectrum can be shortened.

C. Scattered ions As referred to the present application, scattered ions are generated when ions from an ion beam (for example, He ions) interact with a sample, and are scattered from the sample as ions (He ions). Scattered ions usually provide information about the sample surface, as it is very unlikely that the scattered ions will move from the inner surface region of the sample to the surface of the sample and then be released from the sample. As will be described in detail below, when detecting scattered ions, the specific arrangement of one or more detectors generally depends on the type of information desired to be obtained.

In some embodiments, the detected scattered ions can provide topographical information about the sample surface. FIG. 34A typically illustrates an embodiment of an approach that detects scattered ions from different regions of the surface and determines topographic information about the sample surface. In particular, FIG. 34A shows sample 7010 having regions 7012, 7014 and 7016, each of which comprises surfaces 7013, 7015 and 7017. Scatter patterns 7020, 7030 and 7040 show the angular distribution of ions scattered from the surfaces 7013, 7015 and 7017, respectively, when the ion beam is vertically incident. As shown in FIG. 34A, each scattering pattern 7020, 7030 and 7040 is a cosine type distribution. FIG. 34B shows the contribution of the scattered ions detected by the detectors 7041 and 7052 resulting from the topography effect to the relative intensities 7042 and 7052 (dashed and dotted lines, respectively). Thus, for example, assuming that sample 7010 is formed from the same substance over its entire surface, the topography of sample 7010 is performed using the analysis of relative total abundance from detectors 7041 and 7050. Can be decided. Alternatively, assuming that the topography of sample 7010 is known, the contribution of the current topography alone (relative intensities 7042 and 7052) to the total abundance of detected scattered ions is determined by the total presence of the detected scattered ions. It can be removed from the amount to determine the contribution of other effects (eg, changes in material over the surface of sample 7010) to the overall detected scattered ions. The detectors can be placed on the surface as desired, but in certain embodiments, for the type of detector system shown in FIG. 34A, the topographic information is from He ions scattered at a large scattering angle. can get. As an example, in some embodiments, the topographic information from the scattered ions is at an angle of 60 ° or more (eg, 65 ° or more, 70 ° or more, 75 ° or more) with respect to the direction of the ion beam. Determined by detecting To be determined. FIG. 34A shows the use of two detectors, but in some embodiments a single detector (eg, detector 7041 or detector 7050) is used. Alternatively, in certain embodiments, more than one detector (eg, 3, 4, 5, 6, 7, 8) can be used. Generally, when a plurality of detectors are used to detect scattered ions, the detectors are spaced apart from each other with respect to their solid angles with respect to the sample surface. The use of more than two detectors (eg, four detectors) symmetrically arranged with respect to the sample surface makes it possible to detect surface features in both directions orthogonal to the nominal plane of the sample surface. be able to.

Figures 35A-35I generally represent various embodiments of the approach of detecting scattered ions from different regions of the surface and determining topographical information about the sample surface. In particular, FIGS. 35A, 35D and 35G show sample 8050 with regions 8052, 8054, 8056 and 8058 having surfaces 8053, 8055, 8057, 8059 and 8061, respectively. As shown in Figures 35A, 35D and 35G, the surfaces 8055 and 8059 are tilted with respect to the surfaces 8053, 8057 and 8061. Scatter patterns 8070, 8090 and 80110 show the angular distribution of ions scattered from their surfaces 8053, 8057 and 8061 when the ion beam is vertically incident on them. As shown in FIGS. 35A, 35D and 35G, each scattering pattern 8070, 8090 and 80110 is a cosine type distribution. The scattering patterns 8080 and 80100 show the angular distribution of ions scattered from the surfaces 8055 and 8059 when the ion beam is perpendicular to the regions 8054 and 8058. As shown in FIGS. 35A, 35D and 35D, the angular distribution of the scattering patterns 8080 and 80100 is not a cosine-type distribution because the ion beam does not enter perpendicularly to the surfaces 8055 and 8059.

Figures 35B and 35C show the total emission of scattered ions and the hemispherical detector (it may be possible to angularly decompose the scattered ions, spectrally decompose the scattered ions, or both) 80120. It represents the relative abundance of the detected scattered ions when the scattered ions are detected by using. As shown in FIG. 35C, when the detector 80120 is used, there is a shadow effect of the relative abundance of the detected ions. So, for example, assuming that the sample 8050 is made of the same substance over its entire surface, the topography of the sample 8050 should be determined using the analysis of the relative abundance from the detector 80120. Can be done. Alternatively, assuming that the topography of sample 8050 is known, the contribution of the topography alone (relative abundance in Fig. 35D) to the total abundance of detected scattered ions can be determined by the total abundance of detected scattered ions. It can be removed from and the contribution of other effects (eg, changes in material over the entire surface of sample 8050) to the entire detected scattered ions can be determined.

FIGS. 35E and 35F show the total emission amount of scattered ions and the relative abundance of detected scattered ions when the scattered ions are detected by using the upper detector 80130 having a relatively small acceptance angle for the scattered ions. As shown in Figure 35F, the amount of scattered emissions within the acceptance angle of the detector 80130 is substantial in the regions 8054 and 8056 (despite the high total emission of scattered ions in those regions as shown in Figure 35E). Due to its small size, the relative abundance of scattered ions decreases in regions 8054 and 8056. So, for example, assuming that the sample 8050 is made of the same substance over its entire surface, the topography of the sample 8050 should be determined using the analysis of the relative abundance from the detector 80130. Can be done. Alternatively, assuming that the topography of sample 8050 is known, the contribution of the topography alone (relative abundance in FIG. 35D) to the total abundance of detected scattered ions can be determined by the total abundance of detected scattered ions. It can be removed from and the contribution of other effects (eg, material changes over the entire surface of sample 8050) to the detected scattered ions can be determined.

FIGS. 35H and 35I show the total emission amount of scattered ions and the relative abundance of detected scattered ions when the scattered ions are detected by using the upper detector 80140 which has a relatively large acceptance angle for scattered ions. As shown in FIG. 35I, by selecting a suitable acceptance angle for the detector 80140, the relative abundance of detected scattered ions is substantially the same throughout the sample. Changes in the total abundance of detected scattered ions may be due to effects other than changes in surface topography (eg, changes in material over the entire surface of sample 8050).

In certain embodiments, the detection of scattered ions can be used to determine material composition information about the sample surface. One such approach involves measuring the total abundance of scattered ions. There is a single detector (eg, a hemispherical detector) configured to detect scattered ions emitted from the surface 181 of sample 180 (the surface on which the ion beam collides) or the surface 181 of sample 180 (the surface with the ion beam). Scattered ions can be detected using multiple detectors (eg, arranged at different solid angles with respect to the sample surface) that are configured to detect scattered ions from a surface that collides with the sample surface at a range of angles and energies. The total abundance can be detected. In general, the possibility of helium scattering (hence the total abundance of helium scattered, assuming unaffected by other factors such as changes in the topography of the surface sample) is approximately the surface atoms at which helium is scattered. Is proportional to the square of the atomic number (Z value) of. Therefore, as an example, when trying to distinguish a copper (atomic number 29) wire from silicon (atomic number 14) in a semiconductor product, the total abundance of scattered He ions from the copper atom on the surface of the semiconductor product is the semiconductor product. It is about four times the total abundance of scattered ions from silicon atoms on the surface of. As another example, when trying to distinguish a tungsten (atomic number 74) plug from silicon (atomic number 14) in a semiconductor product, the total abundance of scattered He ions from the tungsten atom on the surface of the semiconductor product is the semiconductor. It is about 25 times the total abundance of scattered ions from silicon atoms on the surface of the product. As a further example, when attempting to distinguish the gold (atomic number 79) region in a semiconductor product from silicon (atomic number 14), the total abundance of scattered He ions from the gold atom on the surface of the semiconductor product is the semiconductor product. It is about 25 times the total abundance of scattered ions from silicon atoms on the surface of. As an additional example, when trying to distinguish indium (atomic number 49) from silicon (atomic number 14) in a semiconductor product, the total abundance of scattered He ions from the indium atoms on the surface of the semiconductor product is the semiconductor product. Table

Another approach to determine material composition information about the sample surface by detecting scattered He ions (which can be used in combination with or instead of detection of total abundance) is scattered He ions by energy decomposition and angle decomposition. Including measuring. For example, as shown in FIG. 36, the second lens 226 focuses the He ion beam 192 on the surface 181 of the sample 180. He ion 1102 scatters from surface 181 and is detected by detector 1100. The detector 1100 is designed so that the angle and energy of each scattered He ion detected is known as each angle ε within the acceptance angle of the detector 1100. By measuring the energy and scattering angle of scattered He ions, the mass of atoms on the surface where scattered He ions are scattered can be calculated based on the relationship shown below.<maths num="3"><img file="JP2009517841A_D0006.tif" /></maths> In the formula, E_sIs the energy of the scattered He ions, E_iIs the incident energy of the He ion, M_HeIs the mass of the He ion, θ_sIs the scattering angle, M_aIs the mass of the atom that scatters the He ion.

The detector 1100 includes, for example, an energy decomposition fluorescence system detector, an energy decomposition scintillator system detector, a solid-state detector, an energy decomposition electrostatic prism system detector, an electrostatic prism, an energy decomposition ET detector, or an energy decomposition microchannel. can do. In general, it is preferred that the detector 1100 has a substantial acceptance angle. In some embodiments, the detector 1100 is fixed (eg, annular detector). In certain embodiments, the detector 1100 can be swept through a range of solid angles. We have described systems that include a single detector for detecting energy-resolved and angle-resolved scattered He ions, but there are multiple such systems (eg, 2, 3, 4, 5, 6, 7, 8). Can contain a detector of. In many cases, the use of multiple detectors is preferred as it can allow for large acceptance angles of detected scattered ions.

In some embodiments, detecting the total abundance of scattered He ions can provide a crystal structure for the sample. The total abundance of scattered He ions can vary depending on whether the ion beam is aligned with the crystal structure of the sample. When the ion beam is aligned with the crystal structure of the sample, the ions in the ion beam generally enter a predetermined distance in the sample without colliding with the sample atoms (usually called channeling). It is relatively likely that it will be possible, and the total abundance of scattered He ions is low. On the other hand, when the ion beam is not aligned with the crystal structure, the possibility that the ions in the ion beam at that time enter a predetermined distance of the sample without colliding with the sample atom becomes low, and the scattered He ions The total abundance is high. Therefore, the change in the total abundance of scattered He ions according to the ion beam position on the sample surface can be associated with the crystal information of the substance at that position. For example, there may be regions on the sample surface where the total abundance of scattered He ions is substantially the same. For example, such regions can have the same crystal orientation, where the size of the region is the size of the particles (eg, in a polycrystalline sample containing multiple oriented crystal domains) and / or the size of the crystals. And / or the magnitude of the total abundance of scattered He ions for a substance of a given chemical composition (eg, elemental composition, substance composition) can be determined by the strain of the substance. Information about the distorted region of the sample (whether amorphous or crystalline) can be provided.

Alternatively or additionally, the surface area is irradiated with an ion beam (without rasterizing the ion beam), and then (for example, the Kikuchi pattern obtained by backscattered electrons from the surface of the sample irradiated with the electron beam) is similar. By measuring the pattern of scattered He ions, crystal information about the sample surface can be obtained. The pattern of scattered He ions is analyzed to determine, for example, the orientation of the material at the location of the sample surface irradiated with the ion beam, the lattice spacing, and / or the type of crystal (eg, body-centered cubic, face-centered cubic). be able to.

Scattered ion imaging techniques can be applied to a wide variety of samples. An example of such a type of substance is, for example, a semiconductor product such as a pattern forming wafer that can contain a plurality of conductors surrounded by a matrix-like insulator. Scattered ion imaging techniques can be used to identify equipment defects such as incomplete electrical connections between conductors and / or electrical short circuits between circuit elements. Optionally, this approach can be used for mask repair purposes as well. Other examples of sample types for which scattered ion imaging techniques can be used are metals and alloys. For example, the surface distribution of each substance in the sample can be determined by using an image of a sample containing a mixed substance such as an alloy. A further example of sample types for which scattered ion imaging techniques can be used is a read / write structure for data storage. Additional examples of the types of substances for which scattered ion imaging techniques can be used are biological and pharmaceutical substances.

In general, when the sample surface is irradiated with an electron beam of the type used in a normal SEM, scattered ions are not formed, and therefore, any crystal information or material composition information obtained by the detected scattered He ions is obtained in such an SEM. Not available. This is a significant advantage of the gas field ion microscopes described in the present application (eg, He ion microscopes) over conventional SEMs.

Measurement of scattered He ions using a gas field ion microscope (eg, a He ion microscope) as described herein can provide a number of advantages over conventional Rutherford backscatter measuring devices. The spot size at which incident He ions can be focused on the sample surface can be made much smaller than the spot size of a normal Rutherford backscattering measuring device (generally a spot size of 100 μm to 1 mm or more), and the normal Rutherford backscattering. It enables material composition information about the sample surface that is more accurately localized than what is achieved with the measuring device. Further, while the gas field ion microscopes described in the present application (eg, He ion microscopes) allow pixel-by-pixel rasterization over the entire sample surface, the Rutherford backscattering instrument provides this capability. I don't have it. This can reduce the cost and / or complexity associated with material composition information about the sample surface at various positions of the sample.

D. Primary neutral particles As referred to in the present application, in a primary neutral particle, an ion beam interacts with a sample, and ions from the ion beam (for example, He ion) are emitted from the sample as uncharged neutral electrons (uncharged He atom). It is a neutral electron generated in the case. In contrast to scattered He ions, primary He electrons are relatively sensitive probes in the inner surface region of the sample. As used in the present application, the inner layer surface region is greater than 5 nm below the sample surface (eg, 10 nm or more directly below the sample surface, 25 nm or more directly below the sample surface, 50 nm or more directly below the sample surface) and. The region of the sample is 1000 nm or less directly below the sample (for example, 500 nm or less directly below the sample, 250 nm or less directly below the sample, 100 nm or less directly below the sample). Generally, as the ion energy increases, the probe depth of the ion beam increases. Therefore, high energy ion beams can be used to determine deeper inner surface information for the sample. By taking images of a plurality of He atoms in a sample by changing the ion beam energy (probe depth), it is possible to obtain an analysis result of the depth of material composition information. In some embodiments, tomographic reconstruction algorithms and / or tomography can be applied to depth-dependent information to perform tomographic reconstruction of the sample structure.

In general, using total abundance detection, energy-resolved / angle-resolved detection, or both, using the detector arrangements described above for the corresponding techniques for scattered He ions, and with those described above for scattered He ions. The same mathematical relationship can be used to determine material composition information based on the detection of primary He atoms. However, in general, one or more detectors used for the primary He atom can detect neutral species. Examples of such detectors include microchannel plate detectors, channeltron detectors, scintillators / PMT detectors.

Primary neutral particle (eg, He atom) technology can be applied to a wide variety of samples. An example of such a type of substance is, for example, a semiconductor product such as a pattern forming wafer that can contain a plurality of conductors surrounded by a matrix-like insulator. Primary neutral particle technology can be used to identify equipment defects such as incomplete electrical connections between conductors and / or electrical short circuits between circuit elements. Optionally, this approach can be used for mask repair purposes as well. Other examples of sample types for which primary neutral particle imaging techniques can be used are metals and alloys. For example, the surface distribution of each substance in the sample can be determined by using an image of a sample containing a mixed substance such as an alloy. A further example of sample types for which primary neutral particle imaging techniques can be used is a read / write structure for data storage. Additional examples of the types of substances for which primary neutral particle imaging techniques can be used are biological and pharmaceutical substances.

In general, when the sample surface is irradiated with an electron beam of the type used in ordinary SEMs, primary neutral particles are not formed, and therefore, any crystal information or material composition information obtained by the detected scattered He ions is applied. Not available in SEM. This is a significant advantage of the gas field ion microscopes described in the present application (eg, He ion microscopes) over conventional SEMs.

E. Photon Typical photons of interest include X-ray photons, UV photons, visible photons and IR photons. As referred to the present application, IR photons have wavelengths above 700 nm and up to 100,000 nm (eg 1.2 × 10).^-5keV ~ 1.7 × 10^-3keV), and visible photons are photons with wavelengths above 400 nm and up to 700 nm (eg 1.8 × 10).^-3keV ~ 3 × 10^-3keV), UV photons are photons with wavelengths above 10 nm and up to 400 nm (eg 3.1 × 10)^-3KeV ~ 125eV), and the X-ray photon is a photon having a wavelength of 0.01nm ~ 10nm (for example, 125eV ~ 125keV). Generally, such photons are emitted from the sample surface at a range of angles and energies / wavelengths. However, as explained below, the most interesting information is usually of photons (as opposed to angle-resolved photon information), as the wavelength and / or energy of the photon can provide information about the sample surface. Wavelength and / or energy. Photons can be detected using one or more suitable detectors capable of detecting photons in the form of wavelength decomposition or energy decomposition (see above for detector types). When a plurality of detectors are used, all of the detectors may be of the same type or different detectors, and can be generally configured as desired. The detector is configured to detect photons from surface 181 of sample 180 (the surface on which the ion beam collides), surface 183 of sample 180 (the surface opposite to where the ion beam collides), or both. Can be (see above for detector configuration). In order to increase the signal-to-noise ratio of the detected photons, it is preferable to use a detector capable of collecting photons having a relatively large solid angle. Additional or alternative, the system is one that is close to the surface of the sample and can direct the photons to a usable detector (eg, to increase the effective solid angle of detection of the detected photons). The above optical elements (for example, one or more lenses, one or more mirrors) can be included.

Generally, by detecting the energy and / or wavelength of a photon, it is possible to obtain material composition information (for example, element information, chemical environment information) about the sample. In such an embodiment, the information is primarily related to the surface of the sample. In general, for each element or substance in a given chemical environment, the photons emitted by that element or substance will have a specific energy / energy band and a specific wavelength / wavelength band. As a result, the energy and wavelength of photons emitted from a given location on the surface is usually determined by the material present at that location. Therefore, changes in photon energy or wavelength depending on the position of the ion beam on the sample surface can be associated with changes in one or more elements and / or one or more substances present on the sample surface. Provides material composition information about the sample surface.

Alternatively or additionally, by detecting photons by determining the deexcitation of the sample material, material composition information about the sample can be obtained. This can be achieved, for example, by pulsing the ion beam, irradiating the sample with the ion beam for a short period of time, and then measuring the time it takes to detect the photon, where the time is the photon. It is related to the de-excitation time of the sample substance that releases. In general, each element or substance in a given chemical environment will have a specific deexcitation time.

Since the polarization of photons may be determined by the crystal orientation of the substance in the sample, it is possible to obtain crystal information about the sample by detecting photons in combination with the photon. Therefore, the use of a polarizer allows the polarization of photons emitted by the sample to be determined and provides information on the crystal orientation of the sample.

In general, the information contained in the detected photons is mainly information about the sample surface. However, the detected photons may contain information about the inner surface region of the sample, as the photons can escape from the inner surface region of the sample. Therefore, the detection photons can be used to determine the optical properties of the sample. For example, the transparency of a sample to photons can be investigated by manipulating the ion energy in the ion beam and thus manipulating the probe depth to determine the corresponding effect on the intensity of the detected photons. The intensity of the detected photons with respect to the ion energy (probe depth) can provide information about the transparency of the sample to the photons.

Photon imaging techniques can be applied to a wide variety of samples. An example of such a type of substance is, for example, a semiconductor product such as a pattern forming wafer that can contain a plurality of conductors surrounded by a matrix-like insulator. Photon imaging techniques can be used to identify equipment defects such as incomplete electrical connections between conductors and / or electrical short circuits between circuit elements. Optionally, this approach can be used for mask repair purposes as well. Other examples of sample types for which photon imaging techniques can be used are metals and alloys. For example, the surface distribution of each substance in the sample can be determined by using an image of a sample containing a mixed substance such as an alloy. A further example of sample types for which photon imaging techniques can be used is a read / write structure for data storage. Additional examples of the types of substances for which photon imaging techniques can be used are biological and pharmaceutical substances.

Imaging a sample with photons generated by irradiation with a He ion beam can provide many advantages over photons imaged by other techniques such as SEM. For example, the spot size of the He ion beam on the sample can be smaller than the spot size of the electron beam from the SEM. As a result of its small spot size, the area of the sample irradiated with the He ion beam is carefully controlled compared to the area irradiated by the SEM.

Moreover, since He ions are generally heavier than electrons, the scattering phenomenon does not disperse He ions as easily as scattering electrons in a sample. As a result, He ions incident on the sample surface can interact with the sample with a smaller amount of interaction than the electrons in the SEM. As a result, photons detected by a gas field ion microscope (eg, a He ion microscope) can arise from regions smaller than the photon-producing region in SEMs with similar spot sizes. Therefore, the photons generated by the interaction between the sample and the He ion beam are more local to the sample surface than the photons generated by the SEM (for example, when there is no lateral averaging of the material properties). Can be accommodated.

In addition, the He ion source can also provide a greater depth of focus than the electron source. As a result, the image of the sample obtained using an ion microscope (eg, gas field ion microscope) is larger than the comparative image obtained from photons in SEM when measured along the direction perpendicular to the sample surface. The part can be clearly shown.

F. Secondary ion As referred to the present application, secondary ions are ions formed when an ion beam interacts with a sample to remove monatomic or polyatomic species from a charged sample. The interaction between the incident ion beam and the sample can produce secondary ions. In general, this method is more effective when using noble gas ions (Ar ion, Ne ion, Kr ion, Xe ion) having a mass larger than He.

The detection of secondary ions from a sample can provide material composition information about the sample by calculating the mass of the detected particles. In general, this information will correspond to the material on the sample surface. In some embodiments, the mass of one or more secondary ions is determined by the combination of flight time and a mass degradation detector such as a quadrupole mass spectrometer. The detection of such secondary ions can be performed as follows. By changing the potential applied to the ion optical element in the ion optical device, the ion beam is operated in pulse mode. The pulse of the incident ion is incident on the surface of the sample. Also, as the reference time signal for the detector, a clock signal is used that switches the potential of the ion optics to determine the rate at which the ion beam is turned on and off (see above for the detector). In this way, the flight time of secondary ions from the sample to the detector can be accurately determined.

Based on the flight time of the detected secondary ion, its propagation distance (eg, the distance between the detector and the sample), and its energy, the mass of the particle can be calculated, and the type of chemical species (eg, atom) can be calculated. Can be identified. This information is used to determine the material composition information for the sample.

Secondary ion imaging techniques can be applied to a wide variety of samples. An example of such a type of substance is, for example, a semiconductor product such as a pattern forming wafer that can contain a plurality of conductors surrounded by a matrix-like insulator. Secondary ion imaging techniques can be used to identify equipment defects such as incomplete electrical connections between conductors and / or electrical short circuits between circuit elements. Optionally, this approach can be used for mask repair purposes as well. Other examples of sample types for which secondary ion imaging techniques can be used are metals and alloys. For example, the surface distribution of each substance in the sample can be determined by using an image of a sample containing a mixed substance such as an alloy. A further example of sample types for which secondary ion imaging techniques can be used is a read / write structure for data storage. Additional examples of the types of substances for which secondary ion imaging techniques can be used are biological and pharmaceutical substances.

In general, when the sample surface is irradiated with an electron beam of the type used in a normal SEM, no secondary ions are generated, and therefore any material composition information obtained by the detected secondary ions is obtained in such an SEM. Not available. This is a significant advantage of the gas field ion microscopes described in the present application (eg, He ion microscopes) over conventional SEMs.

G. Secondary neutral particles Secondary neutral particles are neutral particles that are generated when an ion beam interacts with a sample to remove monatomic or polyatomic species from an uncharged sample. The interaction of the incident ion beam with the sample can produce secondary neutral particles. In general, this method is more effective when using noble gas ions (Ar ion, Ne ion, Kr ion, Xe ion) having a mass larger than He. Generally, particles are ionized (eg, by laser-induced ionization, electron-induced ionization) prior to detection in order to access information obtained from secondary neutral particles.

Detection of secondary neutral particles (after ionization) from a sample can provide material composition information about the sample by calculating the mass of the detected particles. In general, this information will correspond to the material on the sample surface. In some embodiments, the mass of one or more of the secondary neutral particles (after ionization) is determined by the combination of flight time and a mass resolution detector such as a quadrupole mass spectrometer. .. The detection of such secondary neutral particles (after ionization) can be performed as follows. By changing the potential applied to the ion optical element in the ion optical device, the ion beam is operated in pulse mode. The pulse of the incident ion is incident on the surface of the sample. Also, as the reference time signal for the detector, a clock signal that determines the rate at which the potential of the ionizer (eg, laser, electron beam) and / or the ion optics is switched is used (see above for the detector). ). In this way, the flight time of the secondary neutral particles (after ionization) from the sample to the detector can be accurately determined.

Based on the flight time of the detected secondary ion, its propagation distance (eg, the distance between the detector and the sample), and its energy, the mass of the particle can be calculated, and the type of chemical species (eg, atom) can be calculated. Can be identified. This information is used to determine the material composition information for the sample.

Secondary neutral particle imaging techniques can be applied to a wide variety of samples. An example of such a type of substance is, for example, a semiconductor product such as a pattern forming wafer that can contain a plurality of conductors surrounded by a matrix-like insulator. Secondary neutral particle imaging techniques can be used to identify equipment defects such as incomplete electrical connections between conductors and / or electrical short circuits between circuit elements. Optionally, this approach can be used for mask repair purposes as well. Other examples of sample types for which secondary neutral particle imaging techniques can be used are metals and alloys. For example, the surface distribution of each substance in the sample can be determined by using an image of a sample containing a mixed substance such as an alloy. A further example of sample types for which secondary neutral particle imaging techniques can be used is a read / write structure for data storage. Additional examples of the types of substances for which secondary neutral particle imaging techniques can be used are biological and pharmaceutical substances.

In general, when the sample surface is irradiated with an electron beam of the type used in ordinary SEM, no secondary neutral particles are generated, and therefore, any material composition information obtained by the detected secondary neutral particles is obtained. , Not available in such SEM. This is a significant advantage of the gas field ion microscopes described in the present application (eg, He ion microscopes) over conventional SEMs.

<u style="single">Illustrative use</u>A. Semiconductor manufacturing (i) Overview Manufacturing of semiconductors typically involves the preparation of products that include multiple layers of material that are sequentially deposited and processed to form integrated electronic circuits, integrated circuit elements and / or different microelectronic devices. Such products are typically filled with various features (eg, circuit lines formed of conductive material, non-conductive material) that are precisely arranged with respect to each other (eg, generally within a few nanometers). Wells, regions formed of semiconductor materials). The position, size (length, width, depth), composition (chemical composition) and related properties (conductivity, crystal orientation, magnetic properties) of a predetermined feature can greatly affect the performance of the product. .. For example, in some cases, if one or more of those parameters are out of the proper range, the product may fail because it cannot function as desired. As a result, in general, it is preferable to perform very good control in each process of semiconductor manufacturing, and to monitor the production of semiconductor products at various steps of the manufacturing process, at various stages of the semiconductor manufacturing process. It is advantageous to have a means capable of investigating the position, size, composition and related properties of one or more features. As used herein, the term semiconductor product refers to an integrated electronic circuit, an integrated circuit element, a microelectronic device, or a product formed during the manufacturing process of an integrated electronic circuit, an integrated circuit element, a microelectronic device. In some embodiments, the semiconductor product can be part of a flat panel display or photovoltaic cell.

Regions of semiconductor products can be formed of different types of materials (conductive, non-conductive, semi-conductive). Exemplary conductive materials include aluminum, chromium, nickel, tantalum, titanium, tungsten, and alloys containing one or more of these metals (eg, aluminum-copper alloys). Exemplary non-conductive materials include boroides, carbides, nitrides, oxides, phosphates, silicates and sulfides of one or more metals (eg, nickel silicate, tantalum boride, tantalum germanium, tantalum nitride). , Tantalum silicate, tantalum nitride silicon and titanium nitride). Exemplary semi-conductive materials include silicon, germanium and gallium arsenide. Optionally, the semi-conductive material can be doped (p-doped, n-doped) to increase the conductivity of the material.

As mentioned above, the manufacture of semiconductor products generally involves depositing and processing multiple layers of material in sequence. A typical step in the deposition / treatment of a given material layer is to image the product (eg, to determine where the desired features to be formed should be placed), suitable materials (eg, conductive). Includes depositing substances, semi-conductive substances, non-conductive substances) and etching to remove unwanted substances from specific locations in the product. In many cases, a photoresist such as a polymer photoresist is deposited / exposed to suitable radiation / selectively etched to help control the position and size of a predetermined feature. The photoresist is typically removed in one or more subsequent processing steps, and it is generally preferred that the final semiconductor product does not contain large amounts of photoresist.

Using the gas electric field ion microscope (for example, He ion microscope) described in the present application, it is possible to investigate semiconductor products in various steps (for example, each step) during the manufacturing process. In particular, by detecting and analyzing one type of particle or a plurality of different types of particles (see above), a gas field ion microscope (eg, a He ion microscope) is used to topo the surface of the semiconductor product. Graffiti information, material composition information about the surface of the semiconductor product, material composition information about the inner layer surface region of the semiconductor product, crystal information about the semiconductor product, voltage contrast information about the surface of the semiconductor product, voltage about the inner layer surface region of the sample. Contrast information, magnetic information about semiconductor products, and / or optical information about semiconductor products can be determined.

The use of the ion microscopes or ion beams described in the present application can provide a variety of different advantages that can reduce the time, cost and / or complexity generally associated with the manufacture of semiconductor products. Illustrative advantages of using the ion microscope or ion beam described herein are relatively high resolution, relatively small spot size, relatively small amount of unwanted sample damage, relatively small amount of unwanted material deposition and /. Alternatively, injection, relatively high quality imaging in a relatively short time, and a relatively high amount of processing can be mentioned.

Hereinafter, a specific example of a processing process in the manufacture of a semiconductor will be described.

(ii) Maskless lithography Semiconductor products typically have a layer of photoresist (eg, a polymer photoresist such as poly (methyl methacrylate) (PMMA) or an epoxy-based photoresist, allyl diglycol carbonate or photosensitive glass) on the surface. Patterning the material so that certain regions of the photoresist are resistant to the etchant (and some regions are not resistant to the etchant), etching regions of the material without the etch resist. Etching, including the deposition of suitable materials (eg, one or more conductive materials, one or more non-conductive materials, one or more semi-conductive materials), and optionally the removal of undesired regions of the material. Manufactured using processing. Typically, the patterning process puts the photoresist at the appropriate wavelength so that some regions of the photoresist are resistant to etching and other regions of the photoresist are not resistant to etching. Includes exposure to radiation patterns. A radiation pattern can be formed on the photoresist by forming an image of the mask on the photoresist or by covering a specific area of the photoresist with a mask and irradiating the uncovered area of the photoresist through the mask. it can.

However, rather than covering the region of the photoresist with a mask prior to irradiation with radiation, an ion beam generated by the interaction of a gas atom with a gas electric field ion source (eg, a He ion source) described herein is used. The photoresist can be patterned to create the desired etching resistant and non-etch resistant regions. This can be done, for example, by rasterizing the ion beam over the photoresist (eg, turning on the ion beam in the region where radiation is desired on the photoresist and irradiating the photoresist). This can be achieved by irradiating the desired region of the substance with ions (by turning off the ion beam in the unfilled region). As a result, semiconductor products can be manufactured by maskless processing.

By using an ion beam generated by the interaction between a gas atom and a gas electric field ion source (for example, a He ion source), one or more of the following advantages can be provided. As mentioned above, the process can be carried out without the use of masks, which can reduce the time, cost and / or complexity associated with the manufacture of semiconductor products. Ion beams with a relatively large depth of focus can be used to pattern relatively thick photoresist materials (eg, thicknesses of 2 μm and above, 5 μm and above, 10 μm and above, and / or 20 μm and below). It may be possible. In addition, the relatively deep penetration of ions that can be achieved with the ion beam serves for high quality processing of standard thickness photoresist materials, as well as for relatively thick photoresist materials. Can also help. In addition, the ion beam has a higher resolution than that generally achieved with an electron beam, enabling the manufacture of features with high accuracy and small size. Further, the pattern formation by the ion beam of the photoresist can be made faster than the pattern formation by the electron beam of the photoresist.

(iii) Combination of ion microscope and focused ion beam Focused ion beams (FIBs) are commonly used in the manufacture of semiconductor products to obtain samples for inspection. Gallium (Ga) ions are commonly used for FIB. Use the FIB for various reasons such as imaging of cross sections through semiconductor products, circuit editing, failure analysis of semiconductor products, preparation of semiconductor product specimens for transmission electron microscopy (TEM), mask repair, etc. Can be done. Optionally, the FIB (eg, as an ion source in the chemical vapor deposition process) can be used to deposit one or more substances on the sample. Typically, FIB is used to remove material from semiconductor products by sputtering. For example, in some embodiments, the FIB is used to slice the semiconductor product and expose a cross section of the product for subsequent imaging with an ion microscope. In certain embodiments, the FIB is used to sputter material from the product to form grooves or vias in the product. This technique can be used, for example, to expose parts of the product that are beneath the surface of the product. An ion microscope can then be used to deposit new material or etch existing material exposed by the FIB by gas-assisted chemical techniques. In some embodiments, the FIB can also be used as the selective sputtering means to remove parts of the semiconductor product, such as conductive material parts on the product. In certain embodiments, the FIB can be used to cut out a portion of the sample that can be analyzed later (eg, using a TEM).

In general, it is preferable to place the FIB accurately on the sample. For this purpose, the gas electric field ion microscope described in the present application (for example, a He ion microscope) can be used. For example, the crossed beam means can be used in both the FIB instrument and the gas field ion microscope, and the position of the FIB can be determined using the gas field ion microscope without moving the sample. With such means, a gaseous electric field ion source can be used to image the sample and provide information that can be used to accurately position the FIB as desired. Such an arrangement can provide many advantages over locating the FIB using SEM. As an example, the use of SEM may generate a magnetic field close to the sample surface, which results in isotope separation of Ga ions, resulting in more than one FIB position in the sample. Become. In many cases, this problem results in using FIB and SEM in sequence rather than simultaneously. However, on the other hand, the gas field ion microscope can be operated in the absence of such a magnetic field, thereby removing the hassle associated with the isotope separation of Ga ions and further using the FIB and gas field ion microscope. Can be used at the same time. This may be preferable when preparing the sample for subsequent testing (eg, TEM testing), for example, where it is desirable for the sample thickness to meet relatively tight tolerances. An additional advantage of using a gas field ion microscope (eg, a He ion microscope) is that the ion beam has a smaller virtual source than the electron beam, so it is typical while still maintaining very good resolution. It has a large working distance compared to its use in SEM. This can alleviate certain spacing restrictions that may exist due to the combined means of FIB equipment and SEM. A further advantage of the gas electric field ion microscopes described in the present application is that SEMs are generally unable to provide information on the inner layer surface of the sample, whereas they can be used with respect to the sample.

(iv) Chemical reaction using gas as an aid Gas-assisted chemical reactions are typically used in the manufacture of semiconductors to add or / or remove material from a given layer. For example, gas-assisted chemical reactions can be used to edit circuits in semiconductors, repairing damaged or mismanufactured circuits formed in semiconductor products. Also, gas-assisted chemical reactions may be used to repair masks in photolithography, where adding or removing substances from the mask results from use or mismanufacturing. Defects can be repaired.

The treatment generally involves the electrons interacting with the activating gas and then engaging in a chemical reaction on the surface of the semiconductor product, adding a substance to the surface, removing the substance from the surface, or both. Includes forming a reactive gas capable of performing. Typically, electrons are generated as secondary electrons due to the interaction of the Ga ion beam with the sample, and / or the secondary electrons due to the interaction of the electron beam (eg, produced by SEM) with the sample. To generate electrons as. Optionally, a suitable pump system can be used to remove unwanted volatile products from surface chemistry.

An example of an activating gas that can be used to remove substances from the surface is Cl.₂, O₂, I₂, XeF₂, F₂, CF₄And H₂O is mentioned. As an example, in some embodiments, a surface region formed of chromium, chromium oxide, chromium nitride and / or chromium oxynitride Cles electrons.₂And / or O₂Can be removed at least partially by interacting with and etching the surface area with the resulting species. As another example, in certain embodiments, the surface region formed by tantalum nitride XeF electrons.₂, F₂And / or CF₄Can be removed at least partially by interacting with and etching the surface area with the resulting species. As a further example, in certain embodiments, the surface region formed by the carbon-containing material H-electrons.₂O and / or O₂Can be removed at least partially by interacting with and etching the surface area with the resulting species.

An example of an activating gas that can be used to deposit material on a surface is WF.₆(W plugs, etc., deposit W).

A chemical reaction using a gas as an auxiliary can be carried out by using an ion beam generated by an interaction between a gas atom and a gas electric field ion source (for example, a He ion source) described in the present application. In such a process, for example, the secondary electrons emitted from the sample by the interaction of the ion beam with the sample can be used as electrons useful for a chemical reaction. The use of such an ion beam can provide several advantages over the use of a Ga ion beam. As an example, a He ion beam can be used to reduce (eg, eliminate) unwanted ion implantation, whereas an undesired Ga injection is a common problem when using a Ga ion beam. It becomes. As another example, a gas electric field ion beam (eg, a He ion beam) can provide improved resolution for a Ga ion beam and / or an incident electron beam (eg, an incident electron beam produced by an SEM). , More accurate and / or controllable use of chemical reactions can be made possible. This means, for example, the undesired interaction of ions with a particular part of the sample (eg, the tail where the contour of the Ga ion beam extends to the undesired sample area where the injection of Ga can cause problems with the performance of the semiconductor product. If it does, it can reduce (eg, remove) what can happen with a Ga ion beam.

(v) Sputtering In the manufacturing process of semiconductor products, it may be desirable to remove substances during certain steps. Therefore, when the ion beam sputters a substance from a sample, the ion beam can be used. In particular, an ion beam generated by the interaction of a gas atom with the gas electric field ion source described in the present application can be used to spatter the sample. He gas ions can be used, but it is generally preferred to use heavier ions (eg, Ne gas ions, Ar gas ions, Kr gas ions, Xe gas ions) to remove the material. During material removal, the ion beam is focused on the area of the sample where the material to be removed is placed.

The advantage of removing material with an ion beam is that it can be removed in a relatively controlled and / or relatively accurate manner. An additional advantage is that sputtering is achieved without the injection of unwanted ions (which often occurs when using Ga ion sputtering, for example, when Ga injection is a side effect of unwanted general sputtering). You can do it.

(vi) Detection of voids During the manufacture of semiconductor products, voids in certain features or layers may be inadvertently formed. In some embodiments, the voids may adversely affect the characteristics of the feature and / or the entire device (eg, electrical, mechanical). In certain embodiments, subsequent treatment steps may open voids, which may be filled with, for example, liquid and / or gaseous components. This can result in corrosion of the base structure, particle defects and / or residue defects on the surrounding wafer surface.

As an example, WF₆TiN during W plug deposition from_xA protective layer is commonly used to protect adjacent dielectrics (eg, boron- and fluorescent-doped silicon glass) from corrosion (from HF emitted during W formation). TiN_xLayer breaks can result in the formation of severe voids. As another example, the deposition of material (eg, dielectric) in a groove (eg, a groove with a relatively high aspect ratio) may result in the formation of bottleneck along with the formation of later voids. As an additional example, void formation may occur during dielectric filling of the shallow groove separation structure. As a further example, voids may be formed during the formation of conductive wires of material (eg, copper wires), which can result in an undesired decrease in electrical conductivity. In some cases, such voids can lead to a lack of electrical conductivity where electrical conductivity is required.

By using the gas field ion microscope (for example, He ion microscope) described in the present application and utilizing the ability to provide information on the inner layer surface of a sample such as a semiconductor product, the formation of voids can be investigated. This property can be used during the manufacturing process of semiconductor products to determine the presence and / or location of voids. This is a clear advantage beyond the use of electron beams, as electron beams generally do not provide this type of inner surface information for the sample.

(vii) Multi-layer movement alignment Multi-layer movement alignment generally refers to the alignment of a featured portion of a predetermined layer in a semiconductor product with a featured portion of a different layer in the semiconductor product. As mentioned above, the formation of semiconductor products generally involves the precise formation of many layers. Typically, semiconductor products contain significantly more than 20 layers. In many cases, each layer can contain a plurality of different features, each of which is precisely and desirablely installed, so that the semiconductor product can function correctly. As an example, a semiconductor product can contain lateral features such as conductive wires, which are present in different layers and are connected to each other by vias. In general, having features within a semiconductor product that are aligned with each other within 100 nm (eg, 75 nm, 50 nm, 25 nm, 15 nm, 10 nm, 9 nm, 8 nm, 7 nm, 6 nm, 5 nm, 4 nm, 3 nm, 2 nm, 1 nm). Is preferable. Only one of these many features can make the entire semiconductor product useless.

The multi-layer movement alignment is generally performed by an optical technique using a test structure having a μm size structure (which is considerably larger than the size of a feature portion of an ultra-small electronic circuit). As such, typically, the amount of wafer clearance occupied by the optical test structure makes it impossible to place the optical test structure within the dye on the wafer. For example, test structures can be placed near the wafer edge, but they still occupy valuable voids on the wafer surface. Also, the optical test structure is expensive because it is manufactured only for alignment purposes. Finally, the use of optical test structures for alignment has limitations with respect to the accuracy with which feature alignment can be determined within different layers.

The gas field ion microscopes (eg, He ion microscopes) described in this application provide relatively high accuracy for various types of information about a sample (eg, topography information, surface material composition information, inner layer area material composition information, etc. The ability to provide crystal information, surface voltage contrast information, inner layer area voltage contrast information, magnetic information and optical information) is very much within the device, allowing the features of the device to be accurately positioned and sized. To help ensure precision, it allows the microscope to be used advantageously during the manufacture of semiconductor products. In particular, the He ion microscope can enable the alignment of the circuit feature of the multi-layer with higher resolution than what can generally be achieved using an optical test structure. Further, the multi-layer movement alignment can be performed according to the purpose because, for example, the gas electric field ion microscope (for example, He ion microscope) described in the present application can image the inner layer surface feature portion of a sample such as a semiconductor product. This can be done without using the manufactured test structure (eg, optical test structure). Therefore, in addition to the costs and / or complexity associated with including a test structure manufactured for the purpose (eg, an optical test structure), there is wasted clearance on the wafer taken up by such test structure. Can be avoided.

(vii) Measurement of limit dimensions The measurement of the limit dimension refers to the measurement of the line dimension of the feature part of the semiconductor product, which may have a significant influence on the performance of the device. Examples of such a feature portion include a wire (for example, a wire of a conductive substance, a wire of a semi-conductive substance, a wire of a non-conductive substance). The semiconductor product can contain one or more feature portions having dimensions of 20 nm or less (for example, 10 nm or less, 5 nm or less, 4 nm or less, 3 nm or less, 2 nm or less, 1 nm or less). In some embodiments, the size of the feature is measured multiple times to provide statistical information about the size of the feature. Measurement of critical dimensions often involves determining, for example, the length of features patterned on the wafer. Wafers (each die containing multiple dies forming a semiconductor product) may be randomly selected from the production line for inspection, or all wafers on the production line may be inspected. Imaging equipment can be used to measure selected critical dimensions at relatively high processing speeds. If the measured critical dimensions are not within acceptable limits, the wafer can be discarded. If multiple samples produced from a particular manufacturing machine have marginal dimensions outside the acceptable range, the machine can be shut down or its operating parameters can be changed.

The He ion microscope system disclosed in the present application can be used for measuring limit dimensions. In particular, the He ion beam can be raster-scanned over the wafer region and the resulting images of one or more wafers can be used to determine one or more limit dimensions. When it comes to measuring marginal dimensions, He ion microscopy systems can offer many advantages over SEMs and other inspection systems. Heion microscope images are usually excessively closer to the detector saturation point due to improved emission at the edge blowout (generally, a topographic feature with a tilt approximately parallel to the beam) compared to comparable SEM images. There are few signals). The reduced edge blowout is the result of a small interaction between the He ion and the sample surface relative to the amount of electron interaction with the sample surface.

In addition, the incident He ions can be focused to a spot size smaller than the comparable incident electron beam. The small beam spot size, combined with a small amount of interaction, provides an image of the sample with better resolution than the image produced by SEM and a more precise determination of the sample's critical dimensions.

The depth of focus of the He ion beam is relatively large compared to SEM. As a result, the resolution of the feature portion of the sample at various depths does not vary when the ion beam is used as compared with the electron beam. Therefore, the use of an ion beam can provide information with excellent lateral resolution at various sample depths, with no variation compared to what can be provided using an electron beam. As an example, by using an ion beam, it is possible to achieve an analysis result of a limit dimension superior to that achieved by an electron beam.

Furthermore, in embodiments where information is obtained based on secondary electrons, at least in part, the relatively high amount of secondary electrons emitted by the ion beam is relatively high for a given current as compared to the electron beam. High signal-to-noise ratios can be achieved. This, in turn, can make it possible to obtain sufficient information about the sample in a relatively short time, increasing the amount of processing for a given current.

Imaging of the sample for determining the critical dimensions can be performed using scattered He ions. This provides the added benefit of material information in addition to high resolution distance measurements.

While using the ion microscopy system to measure marginal dimensions, a flood gun can be used to prevent overcharging of the sample surface (see above). Additional or alternative, very low He ion beam currents (eg, 100 fA or less) can be used. In addition to reducing surface charge and maintaining image solidity, the use of low ionic currents reduces beam-induced damage to certain resist materials.

In some embodiments, it may be necessary to first classify the wafer sample selected for marginal dimension measurement (eg, to measure the cross-sectional dimensions of the sample). Therefore, a heavy gas such as Ne or Ar can be used in an ion microscope to form an ion beam that can be used to slice a sample. Alternatively, a Ga-based FIB can be used to classify the sample. He can then be introduced by purging those gases from the microscopy system, resulting in marginal dimensional measurements with the He ion beam to avoid sample damage during the measurement.

(viii) Line edge roughness and line width roughness The line edge roughness generally refers to the edge roughness of a material line in a semiconductor product, and the line width roughness generally refers to the width roughness of a material line in a semiconductor product. It may be preferable to understand these values to determine if a given semiconductor product has real or potential problems. For example, if adjacent lines formed of a conductive material have edges that bulge outward from each other, the lines may come into contact with each other, resulting in a short circuit. Line edge roughness and / or line width roughness dimensions are 5 nm or less (eg, 4 nm or less, 3 nm or less, 2 nm or less, 1 nm or less, 0.9 nm or less, 0.8 nm or less, 0.7 nm or less, 0.6 nm or less, 0.5 It may be preferable to understand within the range of nm or less). In some embodiments, the line edge roughness and / or the line edge width is measured multiple times to provide statistical information about the size of the feature. In addition, manufacturing tolerances for parameters such as line edge roughness can be very high. For example, the edge roughness of the line of the semiconductor product feature part is within the range of 5 nm or less (for example, within the range of 4 nm or less, within the range of 3 nm or less, within the range of 2 nm or less, within the range of 1 nm or less, and within the range of 0.5 nm or less. Of these, it may be necessary to control within the range of 0.1 nm or less, within the range of 0.05 nm or less, and within the range of 0.01 nm or less).

When determining line edge roughness and line width roughness, wafers may be randomly selected from the production line for inspection, or all wafers on the production line may be inspected. An imaging device can be used to measure line edge roughness and line width roughness at a relatively high processing speed. If the measured line edge roughness and line width roughness are not within acceptable limits, the wafer may be discarded. If multiple samples produced from a particular manufacturing machine have unacceptable line edge roughness and line width roughness, the machine may be shut down or its operating parameters changed. Can be done.

The gas electric field ion microscope disclosed in the present application (for example, a He ion microscope) can be used for measuring the edge roughness of a line and the width roughness of a line. In particular, the He ion beam can be raster-scanned along the length of the feature portion, and the obtained information can be used to determine the line edge roughness and line width roughness with relatively high accuracy. ..

When it comes to measuring line edge roughness and line width roughness, He ion microscopy systems can offer many advantages over SEMs and other inspection systems. Heion microscope images are usually excessively closer to the detector saturation point due to improved emission at the edge blowout (generally, a topographic feature with a tilt approximately parallel to the beam) compared to comparable SEM images. Signal) is low. The reduced edge blowout is the result of a small interaction between the He ion and the sample surface compared to the amount of electron-sample surface interaction.

In addition, the incident He ions can be focused to a spot size smaller than the comparable incident electron beam. The small beam spot size, combined with a small amount of interaction, provides an image of the sample with better resolution than the image produced by SEM and a more precise determination of the line edge roughness and line width roughness of the sample. ..

The depth of focus of the He ion beam is relatively large compared to SEM. As a result, the resolution of the sample feature at various depths does not vary when the ion beam is used as compared with the electron beam. Therefore, the use of an ion beam can provide information with excellent lateral resolution at various sample depths, with no variation compared to what can be provided using an electron beam. As an example, by using an ion beam, it is possible to achieve an analysis result having a line width superior to that achieved by an electron beam.

Furthermore, in embodiments where information is obtained based on secondary electrons, at least in part, the relatively high amount of secondary electrons emitted by the ion beam is relatively high for a given current as compared to the electron beam. It can provide a signal-to-noise ratio. This, in turn, can make it possible to obtain sufficient information about the sample in a relatively short time, increasing the amount of processing for a given current.

Imaging of the sample for determining the critical dimensions can be performed using scattered He ions. This provides the added benefit of material information in addition to high resolution distance measurements.

While using the ion microscopy system to measure line edge roughness and line width roughness, a flood gun can be used to prevent overcharging of the sample surface (see description above). Alternatively or additionally, a very low He ion beam current (eg, 100 fA or less) can be used. In addition to reducing surface charge and maintaining image solidity, the use of low ionic currents reduces beam-induced damage to certain resist materials.

In some embodiments, when it is necessary to first classify the wafer sample selected for measuring line edge roughness and line width roughness (eg, to measure the cross-sectional dimensions of the sample). There is. Therefore, heavy gases such as Ne and Ar can interact with the gas electric field ion source to generate an ion beam that can be used to slice the sample. He can then be introduced by purging those gases from the microscopy system, resulting in marginal dimensional measurements with the He ion beam to avoid sample damage during the measurement.

(ix) Circuit editing As described above, the process of forming a semiconductor product typically involves stacking layers of many different materials in a desired manner and performing suitable treatments on each layer. In general, this includes depositing material on a given layer and / or removing material from a given layer. The final semiconductor product contains many different features in different layers (eg, to form the desired circuit). In general, it is preferable to accurately align the features for the final device to function as desired. Alignment marks are commonly used in semiconductor products to help align the features of a given layer with the features of different layers. However, the use of alignment marks may add extra steps to the entire manufacturing process and / or introduce other complications or costs into the manufacturing process. Further, the presence of a mere alignment mark means that it exists as an area and / or volume of a semiconductor product that cannot be used (eg, for the manufacture of dynamic parts).

As described above, the ion beam can be used to investigate the inner layer surface region of the material. This property can be used to determine the position of specific features of a layer beneath the surface layer, aligning features of different layers of a semiconductor product as desired without the use of alignment marks. be able to.

Using the gas field ion microscope described in the present application (eg, He ion microscope), for example, by a chemical reaction and / or sputtering method using the above gas as an auxiliary, a substance (for example, from an electronic circuit) is removed and /. Or it can be deposited. The advantage of performing these treatments with an ion microscope is that the product obtained with an ion beam can be evaluated, for example, to determine if the desired material has been accurately deposited or removed. This can reduce the costs and / or complexity associated with manufacturing the device and / or increase the processing volume of manufacturing the device. The inner layer circuit can be repaired by combining the removal of substances and / or additional functions. To repair defects on the inner surface, first remove material from the device to a depth that reveals the defects. The defect is then repaired by adding or removing material from the device. Finally, the layers on top of the device are repaired layer by layer by adding new material of appropriate thickness.

The gas field ion microscopes described in the present application (eg, He ion microscopes) are special for circuit editing applications involving small spot sizes and low ion currents due to the controlled and very precise editing of the manufactured equipment. Benefits can be provided.

(x) Mask repair Semiconductor products typically have a layer of photoresist (eg, a polymer photoresist such as poly (methyl methacrylate) (PMMA) or an epoxy-based photoresist, allyl diglycol carbonate or photosensitive glass) on the surface. Patterning the material so that certain regions of the photoresist are resistant to the etchant (and some regions are not resistant to the etchant), etching regions of the material without the etch resist. Includes etching, depositing suitable substances (eg, one or more conductive substances, one or more non-conductive substances, one or more semi-conductive substances), and optionally removing unwanted regions of the substance. Manufactured using a lithography process. Typically, the patterning process puts the photoresist at the appropriate wavelength so that some regions of the photoresist are resistant to etching and other regions of the photoresist are not resistant to etching. Includes exposure to radiation patterns. A radiation pattern can be formed on the photoresist by forming an image of the mask on the photoresist or by covering a specific area of the photoresist with a mask and irradiating the uncovered area of the photoresist through the mask. it can.

Photolithographic masks used in integrated circuits and other microelectronic devices manufactured in the semiconductor industry can be fragile and / or expensive. In addition, the mask manufacturing process can be time consuming and / or require great care. In some situations, manufacturing errors create defects in the mask, despite the precautions commonly taken during the manufacture of such masks. In other situations, mask defects may result from handling or general use. When manufacturing a circuit or other device with a defective mask, the circuit or device may not work correctly. Given the time and cost required to produce a new mask, editing a defective mask can be more cost effective than producing an entirely new substance.

Mask defects generally include excess mask material in the mask area where the material should not be present, and / or absence of the mask material where the material should be present. In either situation, the gas field ion microscope described in the present application (eg, a He ion microscope) can be used to inspect and / or repair the mask.

In some embodiments, the mask is inspected using a gas field ion microscope disclosed herein (eg, a He ion microscope) to see if there are defects, and if so, where the defects are. Can be determined. It is preferred to image the mask by taking advantage of many of the various advantages provided and characterized by the gas field ion microscopes disclosed herein (eg, He ion microscopes).

In certain embodiments, in addition to imaging the mask during mask repair, a gas electric field ion microscope (eg, a He ion microscope) can be used during the repair process. As an example, a gas field ion microscope can be used to place the mask in an appropriate position with respect to the FIB, resulting in a mask by surface chemistry and / or etching of the gas using the FIB as described above. Substances from can be added and / or removed. As another example, in addition to first imaging the mask to determine the presence and / or location of defects, a gas field ion microscope is used to perform surface chemistry and / or etching of the gas as described above. Can add and / or remove substances from the mask. Optionally, while performing a specific repair process (addition of substances, removal of substances) using a gas field ion microscope, another repair process (addition of substances, removal of substances) can be used for other equipment (for example, FIB). )It can be performed.

(xi) Defect inspection Generally, during the manufacturing process of a semiconductor product, the product is inspected for potential defects. Typically, the inspection is performed using a line of means that is always active and fed with wafers, and it is fully automatic. Often, the means are used to determine if there are areas in the wafer where defects can occur. This inspection is performed prior to the defect re-inspection (see description below). The goal of defect inspection is typically to determine if a defect can exist, as opposed to determining the exact nature of a given defect. During defect inspection, the wafer region is analyzed and certain anomalous properties (eg, voltage contrast characteristics, topography characteristics, material properties) are found by the sample with respect to other regions and / or regions of the same wafer. See if it is shown. Typically, for potential defects, pay attention to the coordinates on the wafer (X, Y coordinates) and carefully inspect the wafer position during defect reinspection.

The gas field ion microscope described in the present application (eg, He ion beam) can be used to collect information about the sample during defect inspection. Such microscopes can be used for relatively high throughput and high quality defect inspection. The different contrast mechanisms provided by gas field ion microscopes (eg, He ion microscopes) allow visualization of different types of defects with higher resolution than those generally observable using optical imaging techniques. be able to.

(xii) Defect re-inspection Generally, if a sample is noted to have potential defects during defect inspection, then the sample is subjected to defect re-inspection, where one of the samples with potential defects. Investigate one or more areas to determine the nature of the defect. Based on this information, the processing can be modified to reduce the risk of defects in the final product. Defect inspection is typically performed at a lower speed and at a higher magnification than defect reinspection and can be automated or manually performed to obtain specific information about one or more defects. Using that information, we try to understand why the anomalous results were obtained during the re-examination and the nature and causes of the defects caused by the anomalous results.

Using the gas field ion microscope (for example, He ion microscope) described in the present application, semiconductor products can be investigated in various steps (for example, each step) of the manufacturing process. Topography of the surface of semiconductor products, in particular, using a gas field ion microscope (eg, a He ion microscope) by detecting and analyzing one or more different types of particles (see description above). Information, material composition information about the surface of semiconductor products, material composition information about the inner layer surface region of semiconductor products, crystal information about semiconductor products, voltage contrast information about the surface of semiconductor products, voltage contrast about the inner layer surface region of semiconductor products Information, magnetic information about semiconductor products, and / or optical information about semiconductor products can be determined. The different contrast mechanisms provided by the He ion microscope can enable visualization of defects that are not visible by SEM-based techniques.

By using the ion microscope or ion beam described in the present application, it is possible to provide a wide variety of advantages that can reduce the time, cost and / or complexity generally associated with the manufacture of semiconductor products. Illustrative advantages associated with the use of the ion microscope or ion beam described herein include relatively high resolution, relatively small spot size, relatively small amount of unwanted sample damage, relatively small amount of material deposition and / or Injection, relatively high quality imaging in a relatively short time, and relatively high processing volume.

(xiii) Circuit test During the manufacture of a semiconductor product, the conductivity and functionality of one or more features of the product can be tested. This method generally involves irradiating one or more features with charged particles and then monitoring at the rate at which the charge accumulates. The open circuit will be charged at a different rate than the closed circuit, allowing the open circuit to be confirmed and examined for more detailed inspection. Using the gas electric field ion microscope described in the present application (for example, He ion microscope), an electric charge can be applied to the feature portion by an ion beam, and / or using the gas electric field ion microscope (for example, voltage contrast characteristics). It is possible to monitor whether the charge has leaked (by monitoring). Optionally, an electric charge can be applied using a flood gun (see description above) and whether the electric charge has leaked using a gas electric field ion microscope (eg, by monitoring the voltage contrast characteristics). Can be monitored.

B. Corrosion of metals and alloys He ion microscopes can be used to identify and investigate metal corrosion in various devices and materials. For example, metal fixtures and equipment used in nuclear power plants, military and biomedical applications can be corroded by the harsh environment in which they are placed. Using a He ion microscope, images of those devices and other devices can be created based on the relative abundance of hydrogen (H) in the device, and it functions as a reliable corrosion indicator.

Typically, to form an image based on scattered He ions or atoms, a detector for the ions or atoms is placed on the back of the sample, as opposed to an incident He ion beam. By irradiating the sample with He ions, scattered H atoms and ions are generated from the inside of the sample, and the scattered H atoms and ions can be detected and used to form an image of the sample. Next, the degree of corrosion in the sample can be evaluated using the image of the H abundance. The small spot size and amount of interaction of the He ion beam can result in a high resolution H image of the sample obtained without damaging the sample.

C. Read / write structure for data storage Read / write heads used in magnetic storage devices such as hard disks are manufactured with extremely high tolerances and must be inspected for manufacturing defects prior to installation. These devices often have very high aspect ratios, and the short sides of such devices can be as small as 1 nm. He ion microscopes offer many advantages when used to image those devices during examination. Among them are small spot sizes and amounts of interaction that can result in high resolution imaging of small devices, enabling focused imaging across devices with high aspect ratios along their length. There is a large focal depth that can be provided, and material information provided by the measurement of scattered He ions and / or neutral atoms used to ensure that the small circuit elements are connected correctly.

D. Biotechnology It is often preferable to use non-destructive methods to determine elemental and / or chemical composition information for biological samples. Examples of biological samples include tissues, nucleic acids, proteins, carbohydrates, lipids and cell membranes.

Using the gas field ion microscope (for example, He ion microscope) described in the present application, for example, topography information about a biological sample, substance composition information about the surface of a biological sample, and substance composition information about an inner layer surface region of a biological sample. And / or crystal information about the biological sample can be determined. For example, a gas electric field ion microscope can be used to image immunolabeled cells and intracellular structures. Thus, using the microscope, it is possible to provide the specific advantages disclosed in the present application.

E. Pharmaceuticals Often, therapeutic agents (eg, small molecule agents) will be formed as crystals (eg, as they emerge from solution). For example, it may be preferable to determine the crystal structure of a crystallized small molecule because it can provide information about the degree of hydration of the small molecule, and sequentially provide information about the bioavailability of the small molecule. Can be provided. In some cases, crystal information can result in the small molecule actually being in an amorphous form (as opposed to crystalline) and can affect the bioavailability of the small molecule. it can.

In addition or instead, it is often preferable to use non-destructive methods to determine elemental and / or chemical composition information for biological samples.

Using the gas field ion microscope (for example, He ion microscope) described in the present application, for example, topography information about a biological sample, substance composition information about the surface of a biological sample, and substance composition information about an inner layer surface region of a biological sample. And / or crystal information about the biological sample can be determined. Thus, using the microscope, it is possible to provide the specific advantages disclosed in the present application.

<u style="single">Computer hardware and software</u> In general, any of the analytical methods described above can be incorporated into computer hardware or software or a combination thereof. The above analytical methods can be incorporated into computer programs using standard programming techniques after the methods and calculations described in the present application. The program code is applied to the input data to execute the functions described in the present application and generate output information . The output information is applied to one or more output devices such as display monitors. Each program can be incorporated into a high-level procedure or object-oriented programming language to communicate with a computer system. However, the program can be incorporated into assembly language or machine language as needed. In either case, the language can be a compiled language or an interpreted language. Moreover, the program can operate in a dedicated integrated circuit pre-programmed for it.

A computer-readable recording medium or device (eg, ROM or magnetic disk) that can be programmed for general or special purposes is loaded by the computer to set up the computer when performing the procedures described herein. In order to operate, it is preferable to record each of such computer programs on the recording medium or recording device. In addition, the computer program can exist in the cache memory or the main memory during the execution of the program. Also, when a computer-readable recording medium set using a computer program operates the computer in a specific predefined way to perform the functions described in the present application, the analysis method is set as such. It can be incorporated as a computer-readable recording medium.

<u style="single">Other embodiments</u> Although specific embodiments have been described, other embodiments are possible.

As an example, in one or more of the previous embodiments, the SEM can be used in combination with a gas electric field ion microscope. For example, SEM can be used to produce secondary electrons, Auger electrons, X-ray photons, IR photons, visible photons and / or UV photons. Optionally, SEM can be used to facilitate gas-assisted chemical reactions. The gas electric field ion microscope can be configured in any of the operating modes disclosed in the present application, so that the SEM and the gas electric field ion microscope perform complementary functions.

As another example, the tip of W (111) has been disclosed, but different crystal orientations of W can be used for the tip. For example, the tip of W (112), W (110) or W (100) may be used.

As a further example, in some embodiments, an ion microscope (eg, a gas field ion microscope) uses the microscope in-line for sample analysis of samples related to the semiconductor industry (eg, wafer samples). It can include components suitable for making. In certain embodiments, high speed load locks can be used to automate the ion microscope, for example for semiconductor wafers of standard size. In some embodiments, the system may include a wafer table capable of placing a portion of the sample wafer under an ion microscope at high speed. The ion microscope may also include a scanning system capable of high-speed rasterization of measurement patterns. Optionally, the ion microscope also includes a charge neutralization mechanism, which can reduce the charge on the sample. The ion microscope may also include a wafer height control module for adjusting the working distance. In certain embodiments, the system may be configured to be able to image individual dies (eg, having a length of approximately 50 mm).

The examples shown below are informative and are not intended to be limiting.

1. A 25 mm long emission line formed of single crystal W (111) (250 μm in diameter) was obtained from FEI Company (Hills Baro, OR). The emission line was adjusted to a length of 3 mm and set aside. The V-shaped heating wire was prepared as follows. A 13 mm long polycrystalline tungsten wire (180 μm in diameter) was obtained from Goodfellow (Devon, PA) and washed in distilled water for 15 minutes by sonication to remove carbon residues and other impurities. The line was bent at its midpoint to form an angle of 115 degrees. The region near the apex of "V" was electrochemically etched to prepare for welding in a 1N aqueous solution of sodium hydroxide (NaOH) at an applied AC potential of 1V and a frequency of 60Hz for about 15 seconds. Then, the heating wire was taken out from the etching solution, rinsed with distilled water, and dried.

A V-shaped heating wire was attached to the fixture to ensure that the ends of the wire remained coplanar. The emission line was spot welded to the V-shaped top of the heating line. Both ends of the heating wire were then spot welded to the two columns of the type of support base shown in FIGS. 11A and 11B. The support base was obtained from AEI Corporation (Irbin, CA). The resulting assembly was then ultrasonically washed in distilled water and dried.

After mounting the emission line on the support base and cleaning the support base, the end of the emission line was etched by the following electrochemical treatment. First, a resist material (eg, nail polish from Revlon Corporation (New York, NY)) was applied to a emission line length of 0.5 mm and started from the free end of the line. A small amount of resist was placed on the surface of the cleaning glass microscope slide and the line was immersed in the resist solution 10 times to allow the resist to dry slightly between each immersion. Care was taken to ensure that the top boundary of the resist was in the shape of a circle and that the plane of the circle was kept perpendicular to the axis of the line. Following the final immersion of the emission wire end in the resist material, the wire was dried in air for 1 hour.

Next, a support base to which a resist-coated emission wire is attached is attached to the etching fixture, wherein the etching fixture is (a) a translation device for moving the support base up and down, (b). Included a dish and (c) a counter electrode made of stainless steel to minimize unwanted chemical reactions that extend to the dish. The dish was filled with the etching solution to a level where the etching solution was in contact with the counter electrode. Approximately 150 mL of solution was present in the dish of the etching fixture. The orientation of the support base was adjusted to ensure that the longitudinal axis of the emission line was approximately parallel to the vertical direction (eg, the direction in which the translation device provides translation of the support base). The support substrate was then lowered towards the dish using a translation device until the exposed emission line was just in contact with the etching solution. A high-magnification camera attached to the etching fixture made it possible to easily see the resist layer and the surface of the etching solution, enabling accurate positioning of the emission line with respect to the solution surface.

Next, the above line was further lowered by 0.2 mm in the etching solution. At this position, the resist-coated portion of the emission line was completely immersed in the etching solution.

The etching solution consisted of 150 mL of a 2.5 M NaOH aqueous solution. To facilitate wetting, a drop of surfactant (PhotoFlo 200, Eastman Kodak, Rochester, NY) was added to the etching solution. In addition, a means for gently stirring the etching solution using a magnetic stirrer was used during the etching process.

An external power supply was connected to the pillar of the support base and the opposite pole. It was possible to control the maximum voltage amplitude, pulse duration and waveform of the external power source to provide the etching fixture with specific etching conditions.

A continuous AC pulse at a frequency of 60 Hz was applied to the emission line to facilitate the electrochemical etching process. First, 100 pulses with a duration of 580 ms and an amplitude of 10 V were applied over a total time of 5 minutes. The effect of the applied pulse was to increase the speed of the etching process. The emission line portion immersed in the solution but not covered with the resist material was started to be etched and removed. Local etching of the emission line in this area was observed because the emission line was placed so that only the small uncoated area of the emission line above the edge of the photoresist material was immersed in the solution. As the electrochemical reaction progressed, the diameter of the wire in this region began to narrow due to the etching process.

Next, the pulse duration of the external power supply was adjusted to 325 ms, and 60 pulses of this duration were applied over a total time of 5 minutes. In addition, these pulses facilitated the electrochemical etching process, resulting in an etched region of the emission line with a very small diameter.

Finally, the pulse duration of the external power source was adjusted to 35 ms and individual pulses were applied to the emission line until the etching was completed and the resist-coated portion of the emission line dropped into the etching solution. The support substrate was then removed from the etching fixture, rinsed with distilled water and dried under a stream of nitrogen.

Next, the emission line (still attached at the time of the support base) was examined by SEM to verify that the etched tip had a suitable shape. The tip of the emission line was imaged using an AMRAY 1860 SEM operating at 5 keV and having a probe size of 3 nm. A support base was placed in the sample area of the SEM on a sample manipulator with manual tilt and turntable. Images of the source were obtained from several different observation points and magnifications, verifying that the tips were shaped almost exactly.

Next, using SEM images, the characteristics of the average perfect conical angle, the average tip radius, and the average conical direction of the tip apex of the line were clarified as explained above. The images used for these measurements were taken at a magnification of 65,000 x along the observation axis oriented at right angles to the axis of the emission line. The slope of the emission line was adjusted using an SEM sample manipulator to ensure that the emission line was oriented at right angles to the observation axis. To make average measurements of the tip cone angle, cone direction and radius, the tip was rotated 45 ° (around the axis of the emission line) between successive images using an SEM sample manipulator. It gave a set of eight images from different viewpoints, and then used the images to determine the cone angle, radius of curvature and direction of the tip.

Four of the images from the eight viewpoints are shown in Figures 37A to 37D. Each of the SEM images was digitized in bitmap format and then analyzed using a custom algorithm developed by the MathCAD software package (PTC Incorporated, Needam, MA). Initially, a Gaussian convolution algorithm was applied to smooth each image and reduce image noise, especially the noise caused by SEM vibrations that occur during imaging. Next, a filtering step based on the intensity value of the threshold was applied to each image to emphasize the boundary between the tip of tungsten and the black background. Next, the boundary of the tip of each image is defined as a set of non-zero intensity points (X, Y) that form a boundary between the image pixel corresponding to the tip and the image pixel corresponding to the black (eg, zero intensity) background. It was determined. A set of points (X, Y) for one of the leading figures is shown in Figure 38. A similar set of boundaries was determined for each of the eight perspective views at the tip.

Prior to calculating the slope of a given boundary curve, a smoothing algorithm was applied to the curve to ensure that the local slope of the curve was relatively insensitive to noise and other small signal changes. A smoothing algorithm consisting of fitting raw data (X, Y) has been found to show a quartic polynomial and well explain the shape of the tip. The effect of the smoothing algorithm was to ensure that the first derivative of this curve was not overly affected by small changes in shape on either side of the top position.

Following the smoothing step, the slope dY / dX was calculated at each point X along the boundary curve for each figure using a difference algorithm. FIG. 39 shows a graph of the slope calculated at the points along the boundary curve corresponding to X of the boundary curve shown in FIG. 38.

For a specific figure of the tip, the position on the boundary curve corresponding to the figure where the slope obtains a zero value is specified as the top of the tip, and the marker X_TopWas given. Marked at the position on the boundary curve that corresponds to the point (X, Y) where the slope of the boundary curve obtains a value of 1 closest to the top of the tip.₊₁Was given. Marked at the position on the boundary curve that is closest to the top of the tip and corresponds to the point (X, Y) where the slope of the boundary curve obtains a value of -1._-1Was given.

The tip geometric parameters were then determined using those measurement points. X the left radius of the tip in a particular figure₊₁And X_TopIt was calculated by multiplying the absolute value of the difference between them by 1.414. X the right radius of the tip in a particular figure_-1And X_TopIt was calculated by multiplying the absolute value of the difference between them by 1.414. Next, based on the left radius value and the right radius value, the radius of curvature of the tip in a particular figure was calculated as the average of the left radius value and the right radius value.

Calculations of the right-side radius, left-side radius, and tip radius of curvature were repeated for each of the eight perspective views of the tip. Next, the average tip radius was calculated as the average of the radius of curvature measurements of the tip in all the figures of the tip. For the tips shown in FIGS. 37A to 37D, it was determined that the average tip radius was 62 nm.

In addition, the standard deviations of all the left and right radii of the tip were calculated and expressed as a percentage of the average tip radius. It was determined that the eccentricity of the tips shown in FIGS. 37A to 37D was 11.9%.

In addition, the conical angle of the tip in each of the eight perspective views was determined. In the boundary curve corresponding to each figure, the left and right contacts on the boundary curve are located 1 μm from the top of the tip on the left and right sides of the top of the tip when measured along the Y direction as explained above. there were. Next, the angle of the left cone of the tip in a particular figure was determined as the angle between the tangent of the boundary curve at the left contact and the line parallel to the Y axis and penetrating the left contact. The right conical angle of the tip in a particular figure was determined as the angle between the tangent of the boundary curve at the right contact and the line parallel to the Y axis and penetrating the right contact. Finally, the perfect cone angle was determined as the sum of the magnitudes of the left cone angle and the right cone angle.

Next, the average perfect cone angle of the tip was determined by calculating the average of eight measurements of the perfect cone angle of the tip from the eight perspective views of the tip. For the tips shown in FIGS. 37A-37D, for example, it was determined that the average perfect conical angle was 34.5 °.

For the specific figure at the tip, the cone direction was calculated as half the absolute value of the difference in magnitude between the left and right cone angles. By repeating this determination for each of the eight figures at the tip, eight measurements in the conical direction of the tip were obtained. The average conical direction of the tips was then calculated as the average of eight measurements in those conical directions. For the tips shown in Figures 37A to 37B, it was determined that the average conical direction was 2.1 °.

A set of criteria based on measurements of mean tip radius, radial eccentricity, mean cone angle and mean cone direction was used to determine if a given tip was acceptable for use with a He ion microscope. In general, those criteria were as follows: When the measured average cone angle is 15 ° to 45 °, the average tip radius is 35 nm to 110 nm, the standard deviation of the tip radius of curvature measurement is less than 30%, and the mean cone direction is less than 7 °. The tip was accepted. Finally, the tips shown in Figures 37A-27D met each criterion, so this tip was approved for use with a He ion microscope.

After verification of the tip geometric features, the tip was inspected with a custom FIM. The FIM includes a mounting area for a support assembly that supports the tip, a high-voltage power supply for biasing the tip, an extractor close to the tip, and a detector for recording the ion emission pattern from the tip. Including.

The extraction section was arranged at a distance of 5 mm from the tip and had an opening of 10 mm. The extraction part was grounded to the external grounding part. For the detector, a combination microchannel plate (MCP) and an image enhancement tube (Bale Electro-Optics Incorporated, Starbridge, MA) were placed 75 mm from the extraction section.

The support assembly including the tip is installed in FIM, and the FIM chamber is 1 x 10^-8Exhausted to Torr background pressure. The tip was cooled to 77K using liquid nitrogen as a coolant. After temperature equilibration, the source was heated to 900 K for 5 minutes to desorb condensation and other impurities formed on the tips during the process. Heating of the tip was achieved by applying an electric current to the heating wire with the welded tip. The current was applied using a power source having a certain power capacity (Bertan type IB-30A, Spellman High Voltage Incorporated, Howpurge, NY). The temperature was measured using an optical thermometer (Pyrometer, Windsor, NJ).

Then, the tip was cooled to 77K again, the extraction part of FIM was grounded, and the tip was biased to + 5kV with respect to the extraction part. 1x10 in the FIM room^-5High-purity He gas (purity 99.9999%) was introduced with Torr. The tip bias was gradually increased to + 29 kV until a He ion image corresponding to the He ion emanating from the tip was observed by the detector. The FIM emission pattern corresponded to about 300 atoms on the tip surface. Based on the FIM pattern, the single crystal composition and W (111) orientation of the tip were verified.

Next, the tip was polished to obtain a terminal atomic trimer at the top of the tip. Background pressure in FIM chamber is 1.2 × 10^-8Helium gas was discharged from the FIM chamber until it was less than Torr. Next, the tip was heated to a temperature of 1500 K for 2 minutes by applying an electric current to the heating wire as described above. 1x10^-5Oxygen gas was introduced into the FIM chamber near the tip by the pressure of Torr. After 2 minutes, the temperature of the tip was lowered to 1100K. After 2 minutes at 1100K, the oxygen supply was stopped and the tip was cooled to about 77k. Approximately 15 minutes after the oxygen supply was stopped during cooling, the background pressure in the FIM chamber was 1.2 x 10^-8The remaining oxygen gas was discharged from the FIM chamber until it was less than Torr.

When cooled to the temperature of liquid nitrogen, the extraction section was biased as described above, and the tip was again biased to + 5kV with respect to the extraction section. He gas 1x10^-5It was introduced into the FIM chamber under the pressure of Torr, and the FIM was operated again as described above to obtain a He emission image at the tip. The voltage at the tip was gradually increased until the FIM image at the tip was captured by the detector at a bias potential of about + 18 kV at the tip.

The observed FIM pattern contained adsorbed atoms (extra atoms added to the desired three atom trimer structure at the top of the tip). Adsorbed atoms were slowly removed by electric field evaporation at the tip bias potential of + 18 kV. During the field evaporation, the tip image was captured and monitored on a regular basis to determine when to stop the field evaporation process. Adsorbed atoms were removed one by one until a clear FIM image of the atomic trimer was observed at the top of the tip. Moreover, in addition to the atomic trimer, the ridge of the triangular pyramid was clearly observed.

Atomic trimers were slowly removed by further tip electric field evaporation. By slowly increasing the tip bias above + 18 kV, the trimer atoms were removed one by one, resulting in the rounded tip observed in the FIM image recorded by the detector.

In addition, the tip bias potential was increased to + 28 kV. During this process, the electric field evaporation of the tip atom was continued. At a bias potential of + 28 kV, other atomic trimers were obtained at the apex of the tip. A FIM image of the second trimer is shown in FIG. After obtaining the second trimer, the tip bias potential was lowered to achieve the maximum angular intensity of the FIM emission pattern. This happened with a tip bias of + 23kV. By adjusting the tip bias, the maximum angular intensity was determined to obtain the highest observed brightness of the atoms selected in the FIM emission pattern. By measuring the He ion current from the trimer while adjusting the potential bias at the tip, the bias at which the maximum angular emission intensity occurred was verified. The He ion current was measured using a Faraday cup placed in the path of the He ion beam.

Next, the bias potential at the tip was slowly increased beyond + 28 kV, and the atoms were electrovaporated from the top of the tip by electric field evaporation, thereby blunting the tip into a substantially spherical end shape. Field evaporation was continued until another atomic trimer was obtained on the tip surface with a bias potential of + 34 kV. In order to verify the reproducibility of the tip reconstruction means, the polishing process was repeated more than twice to obtain a new atomic trimer at the tip apex. After reconstruction of the two consecutive trimers, the supply of helium gas was stopped, the applied tip bias was removed, the tip was warmed to room temperature, and the pressure in the FIM chamber was slowly equalized to atmospheric pressure. The tip, which remained attached to the support assembly, was stored on a shelf for two weeks before use with a helium ion microscope.

A support assembly including the above tip was installed in a helium ion microscope system similar to the system shown in FIGS. 1 and 5. The elements of the system were configured as follows. The extractor was located 1 mm from the tip and had an opening with a diameter of 3 mm. The first lens of the ion optical device was placed at a distance of 30 mm from the extraction unit. After passing through the first lens, the ions passed through an alignment deflector configured as a quadrupole electrode. A throttle with an opening with a diameter of 20 μm was further placed along the ion path to selectively block part of the ion beam. The intersection of the ion orbits was placed at a distance of 50 mm in front of the aperture. An astigmatism corrector configured as an octupole electrode was placed after the diaphragm to adjust the astigmatism of the ion beam. A scanning deflector configured as an octupole electrode was placed after the astigmatism corrector to enable rasterization of the ion beam over the sample surface. The second lens was placed at a distance of 150 mm from the diaphragm, and the ion beam was focused on the sample surface using the second lens. The second lens was shaped as a flat-headed right-angled cone and had a perfect conical angle of 90 °.

First, the ion microscopy system was evacuated, so the basal pressure in the tip region was about 2 × 10.^-9It was Torr. The tip was cooled to about 80 K using liquid nitrogen. The extractor was grounded and then a + 5 kV bias was applied to the tip with respect to the extractor.

By applying an electric power of 8 W to the heating wire, the tip was heated until the tip visibly emitted light (corresponding to the tip temperature of about 1100 K). Photons emitted from the luminescent tip were observed through the side openings of the ion optics using a mirror tilted 45 ° with respect to the plane perpendicular to the longitudinal axis of the ionic optics. For this reason, the mirror was introduced into an ion optical instrument at a position directly below the alignment deflector through a side opening in the ion lens barrel. The tip was repeatedly tilted and moved until the light emitting tip was directed almost along the longitudinal axis of the ion optical instrument. Proper alignment of the tip with the longitudinal axis was achieved when the light emitting tip appeared as a circular point source. If the tip appeared in a rod shape, the tip was misaligned.

The tip was cooled while maintaining the tip with a potential bias of + 5 kV with respect to the extraction section. When the tip is cooled to liquid nitrogen temperature, 1 x 10^-5He gas was introduced into the tip region under the pressure of Torr. As mentioned above, the ion microscopy system operated in SFIM mode and produced an image showing the tip He ion emission pattern. The image shows the shape of the tip with atomic accuracy. Using the alignment electrode, the ion beam generated from the tip was rasterized over the surface of the diaphragm. The serrated voltage function was applied to each axis alignment deflector, and the serrated maximum voltage function of 150 V was applied to the common external grounding part of the microscope system to achieve rasterization at a frame rate of 10 Hz. The raster pattern scanned 256 points in each of the two orthogonal directions across the axis of the ion optics. No astigmatism corrector and scanning deflector were used in this imaging mode.

To detect ions passing through the aperture, a copper sample is placed under the second lens and the MCP detector is positively biased (+ 300V with respect to the common external ground) to the sample and the sample. Secondary electrons emitted from the copper sample due to the interaction between the incident He ions were measured. The detector was placed at a distance of 10 mm from the sample and oriented parallel to the plane of the sample.

The acquisition system sampled the detector signal at each raster point to produce a tip SFIM image for display on a monitor. To facilitate imaging, the potential of the first lens in the ion barrel was set to 77% of the tip bias. The SFIM image was then maintained at a nearly constant magnification and intensity while increasing the tip bias. While observing on the SFIM image, the tip bias was slowly increased to eliminate unwanted adsorbed atoms and create a tip with an atomic trimer at its apex. This trimer was removed by further increasing the tip bias potential to cause electric field evaporation of the tip atom. Field evaporation was continued until a new atomic trimer was formed at the top of the tip at an applied tip potential of + 23 kV. The resulting SFIM image of this tip is shown in Figure 41.

One of the trimeric with the alignment deflector, astigmatism corrector, scanning deflector and second lens off (eg, at zero potential with respect to the common external ground of the microscopy system). Atoms were selected and the tip was tilted and translated while adjusting the intensity of the first lens in 100V increments. Operating the microscope system in FIM mode, the detector collected FIM emission images at the tip. When adjusting the intensity of the first lens, the tip was repeatedly tilted and translated until the center position of the tip on the FIM image did not change depending on the image.

Next, the diaphragm was placed at an appropriate position, and the potential applied to the alignment deflector was adjusted to control the position of the ion beam at the diaphragm. The part of the ion beam transmitted through the diaphragm was imaged by a detector, and the alignment deflector was repeatedly adjusted using the image of the detector.

A scanning deflector was used to rasterize the ion beam transmitted through the diaphragm over the sample surface. A recognizable high-contrast feature (copper lattice) on the surface of the sample (part number 02299C-AB, Structure Probe International, Westchester, PA) was placed in the path of the ion beam under the second lens and described above. The secondary electron image of the feature portion was measured by a detector using the above-mentioned configuration.

The intensity of the second lens was adjusted so that the ion beam was roughly focused on the sample surface. The potential bias applied to the second lens was about 15 kV with respect to the common external ground. Focus quality was visually evaluated from sample images recorded by the detector. By slowly adjusting the intensity of the second lens (at a frequency of 1 Hz and amplitude modulation of about 0.1% of the operating voltage of the second lens) and observing the misalignment of the feature, the axis of the second lens of the ion beam. The alignment with respect to was evaluated. By adjusting the voltage of the alignment deflector, the beam alignment of the final lens was optimized. The alignment was optimized when the center position of the image measured by the detector changed little while adjusting the intensity of the second lens.

Next, as a result of imaging the sample at a high magnification by adjusting the intensity of the second lens, the field of view of the sample was about 2 square μm. Focus asymmetry was minimized by adjusting the control of the astigmatism corrector. This control was adjusted by observing images of the edges in all directions, especially observing the sharpness of the edges. Astigmatism correction was completed when the sharpness of the focal image was the same in all directions. Typically, only 30 volts was applied to the astigmatism corrector to achieve this condition. At this point, the helium ion microscope was fully operational.

Various samples were imaged using an operable microscope. Sample images recorded by measuring secondary electrons are shown in FIGS. 42 and 43.

Imaging conditions included a wide range of beam currents (100pA ~ 1fA). The beam current was controlled in several ways. First, an electric diaphragm mechanism was used to place different diaphragms with holes of different diameters in place. The drawing mechanism included a drawing with a diameter in the range of 5 μm to 100 μm. Second, by adjusting the focal intensity of the first lens and bringing the beam crossing closer to the aperture plane of the ion optics, a large ion current reached the sample. On the contrary, by adjusting the focal intensity of the first lens and further moving the beam from the diaphragm plane, a small ion current passed through the diaphragm. Third, the pressure of the helium gas in the tip region was increased or decreased, and the ion beam current was increased or decreased, respectively.

Typically, the beam energy was selected for optimum angular intensity, typically the beam energy was in the range of 17 keV to 30 keV. The beam energy changed with time according to the shape change of the tip.

The type of detector to be used and the setting of the detector were selected according to the type of sample examined by the ion microscope. An ET detector was used with a metal grid biased to about + 300 V against a common external ground to measure secondary electron images of the sample. The scintillator inside the ET detector was biased to + 10kV with respect to the external ground, and the increase in internal PMT was adjusted to produce the largest possible signal without saturation.

In addition, an MCP detector (manufactured by Barre Electro-Optics, Starbridge, MA) was used to detect secondary electrons and / or scattered He from the sample. The MCP grid, front and back, respectively, could be biased against the external ground. An increase in detectors was achieved by positively biasing the back of the MCP with respect to its front edge. A typical boosted voltage was 1.5 kV. The collector plate adjacent to the back was biased to + 50V with respect to the back. The detection signal from the collector plate was in the form of a small fluctuating current overlaid on a large positive voltage. For secondary electron collection, the anterior surface and lattice of the MCP were biased to + 300V. For scattered He collection, the anterior surface and grid were biased to -300V.

If necessary, the raster speed was adjusted to the optimum imaging conditions for each sample. The residence time per pixel was in the range of 100 ns to 500 μs. Due to the short residence time, noise was reduced by averaging multiple scans. This was done with continuous line scans and continuous frame scans.

The image shown in FIG. 42 is an image of a plurality of carbon nanotubes on a silicon substrate. The image was obtained by detecting secondary electrons from the surface of the nanotube. The ET detector was placed at a distance of 8 mm from the sample and 15 mm off-axis from the ion beam, and oriented at an angle of 20 ° with respect to the sample plane. The He ion beam current was 0.5 pA and the average ion energy was 21 keV. The ion beam was raster-scanned with a residence time of 200 μs per pixel, and the total image acquisition time was 200 s. The field of view of the image was 4 μm.

The image shown in FIG. 43 is an image of an aluminum column on a silicon substrate. The image was obtained by detecting secondary electrons from the surface of the nanotube. The MCP detectors of the above types had a + 300 V biased grid and anterior surface with respect to the external ground, were placed at a distance of 10 mm from the sample and oriented parallel to the sample plane. The He ion beam current was 0.5 pA and the average ion energy was 24 keV. The ion beam was raster-scanned with a residence time of 200 μs per pixel. The field of view of the sample surface was 1 μm, which was obtained by applying a maximum voltage of 1 V to the scanning deflector.

This tip-based operation in a helium ion microscope continued for several weeks without the need to degas the system at all to enable the ion source. As the trimer atoms were removed, intentionally or with normal use, the tip end shape became more spherical as shown in the SFIM image shown in FIG. Pyramid reconstruction (polishing) in place was performed, if necessary, by using the same heat and oxygen construction formulation as originally performed with FIM to polish the tip. In general, each rebuild process took less than 5 minutes, otherwise the system was available for the last few weeks. Overall, the tip was reconstructed more than eight times. An image of the reconstructed atomic trimer at the top of the tip is shown in FIG.

2. The W (111) tip was attached to the support assembly and electrochemically etched according to the procedure described in Example 1. The SEM image of the tip is shown in FIG. The geometrical characteristics of the tip were determined according to the procedure in Example 1. For this tip, it was determined that the average tip radius was 70 nm. The tip was approved for use based on the criteria of Example 1.

After verifying that the tip geometry was acceptable, the source assembly containing the etched tip was placed in the FIM described in Example 1. The configuration of the FIM was the same as that described in Example 1 except as shown below. The potential bias on the tip was slowly increased to + 21.8 kV with respect to the extractor. The electric field evaporation of the tip atom occurred as the potential increased. After reaching + 21.8 kV, the potential at the tip was lowered to + 19.67 kV. The FIM image of the tip shown in FIG. 47 was obtained with the tip maintained at this potential. Using this image, the single crystal structure and accurate orientation of the tip were verified.

The tip was then polished to create an atomic trimer on top of it. Helium was discharged from the FIM chamber, and the tip was heated by applying a constant current of 4.3 A to the tip for 20 seconds. The tip was observed using a tilted mirror installed in the FIM lens barrel and angled so that the light propagating along the lens barrel axis was directed toward the side opening of the lens barrel. The luminescence (eg, photons emitted from the tip) was invisible to the naked eye, so the tip was cooled for 5 minutes. Next, the tip was heated by applying a constant current of 4.4 A to the tip for 20 seconds. The luminescence was invisible to the naked eye, so the tip was cooled for 5 minutes. Next, the tip was heated by applying a constant current of 4.5 A to the tip for 20 seconds. The luminescence was invisible to the naked eye, so the tip was cooled for 5 minutes. Next, the tip was heated by applying a constant current of 4.6 A to the tip for 20 seconds. At this temperature, the luminescence was clearly visible from the tip. Therefore, it was confirmed that the current required to induce light emission at the tip was 4.6 A. The source was then cooled for 5 minutes.

Next, a negative bias was applied while monitoring the electron emission current from the tip. The bias was increasingly negative until an electron emission current of 50 pA was observed from the tip. The tip bias at this current was -1.98 kV. With this bias still applied to the tip, a heating current of 4.6 A was applied to the tip. After about 20 seconds, the light emission at the tip was observed again. After the luminescence of the tip was observed, the heating of the tip was extended for another 10 seconds. Then, the bias potential and heating current applied to the tip were eliminated from the tip, and the tip was cooled to the temperature of liquid nitrogen.

When the tip was cooled, a positive bias of + 5 kV was applied to the tip with respect to the extractor. 1x10 in the FIM chamber near the tip^-5He gas could be accommodated under the pressure of Torr. As described in Example 1, a FIM image of the top of the tip was obtained. As the bias increased, the FIM image looked clearer. The image in Figure 48 was observed with a tip bias of + 13.92 kV. The image shows the ridges of the pyramids corresponding to the atomic trimers and the bright central apex.

Some of the emitted atoms on the tip were loosely bonded adsorbed atoms, which were removed by increasing the electric field strength by electric field evaporation of the tip atom. In addition, the tip bias was increased and the first and second trimers were removed by electric field evaporation to + 21.6 kV. After reaching this potential, the tip bias was lowered to + 18.86 kV and the FIM image of the tip shown in FIG. 49 was recorded.

Based on the criteria confirmed in Example 1, the tip was confirmed to be viable and removed from the FIM. About a month later, the tip was mounted in a helium ion microscope configured as described in Example 1. In the treatment described in Example 1, the trimers were reconstructed and evaporated multiple times, except that no oxygen gas was used. Instead, the trimer reconstruction process applies a specific negative potential to the tip (to create an electron radiation current of 50pA) while simultaneously heating the tip with a current of 4.6A applied to the heating wire. Relied on to provide a visible luminescence of the heating wire for 20 seconds. The tip remained in the helium ion microscope and provided use for more than 4 weeks without the need to degas the system to enable the tip. During this period, the tips were reconstructed multiple times using the negative potential bias and heating procedures described above. A SFIM image of the reconstructed trimer at the tip is shown in FIG.

An image of a semiconductor sample recorded using a He ion microscope equipped with this tip is shown in FIG. 51. The sample contained a wire of aluminum metal deposited on the surface of a silicon oxide substrate. An unknown paint was deposited on each of the materials in the line.

A scanning voltage with a maximum amplitude of 1 V was introduced into the scanning deflector to create a field of view of 10 μm on the sample. As described in Example 1, the potentials of the first lens and the second lens, the potentials of the alignment deflector and the astigmatism corrector are adjusted to control the portion of the He ion beam passing through the aperture, and the sample position. Controlled the quality of the beam focus at. The sample was tilted and rotated during imaging to reveal three-dimensional properties and details of the sidewalls.

The image shown in FIG. 51 was recorded by measuring secondary electrons from the sample surface. The MCP detector was placed at a distance of 10 mm from the sample and oriented parallel to the sample surface. The grid and front of the MCP were biased to + 300V with respect to the common external ground. The He ion beam current was 4 pA and the average ion energy was 21.5 keV. The total image collection time was 30 s.

An image of another semiconductor sample taken using this tip is shown in FIG. The sample was a multilayer semiconductor device having a surface feature portion made of metal. Images were recorded by measuring the secondary electrons emitted from the sample surface by interacting with the incident He ions of the sample. A maximum scanning voltage of 150 V was applied to the scanning deflector to create a 1.35 mm field of view on the sample surface.

The sample was observed from the viewpoint of covering the whole. This shows many features on the sample surface. To record the image, an MCP detector with a + 300 V biased grid and anterior surface to a common external ground was placed at a distance of 10 mm from the sample and oriented parallel to the sample surface. The He ion beam was 15 pA and the average ion energy was 21.5 keV. The ion beam was raster-scanned with a residence time of 10 μs per pixel.

3. The tip of this example was prepared using the procedure described in Example 2 and aligned in a helium ion microscope. The geometrical characteristics of the tip were determined according to the procedure in Example 1. The tip was approved for use based on the criteria of Example 1.

Direct or extrapolation measurements made it possible to obtain images of the sample with known beam currents and known collection times. Beam current was carefully monitored using a Faraday cup coupled with a pico ammeter (Type 487, Keithley Instruments, Cleveland, OH). In addition, the He pressure in the tip region was carefully monitored using a Baynard Alpert type ionization gauge (Varian Vacuum Incorporated, Lexington, MA). In situations where the He ion current was too low to measure accurately (eg, less than about 0.5 pA), the ion current was determined by extrapolation based on the measured He gas pressure. Typically, the He gas pressure and the He ion current are linearly proportional to each other, and the linear relationship is consistent from tip to tip.

The sample was a gold lattice sample with local features (Part No. 02899G-AB, Structure Probe International, Westchester, PA). The sample was imaged by measuring the secondary electron emission from the sample surface according to the incident He ion. To record the image, a 40 mm diameter annular chevron type MCP detector (Bale Electro-Optics, Starbridge, MA) was placed at a distance of 10 mm from the sample and oriented parallel to the sample surface. The detector had a solid angle of about 1.8 steradians and was symmetrical with respect to the ion beam. As shown in FIG. 66, the detector was attached directly to the bottom of the second lens. There was an internal metal grid (+ 300V) that biased the front of the MCP positively (+ 300V) against the common external ground and then positively biased (against the common external ground).

The average ion energy was 20 keV. Images of the sample were measured with beam currents of 1pA, 0.1pA and 0.01pA, respectively, and are shown in Figures 53, 54 and 55, respectively. The total image acquisition time was 33 seconds, 33 seconds and 67 seconds, respectively.

For the first two images (FIGS. 53 and 54), the image size was 1024 x 1024 pixels. For the third image (FIG. 55), the image size was 512 x 512 pixels. In each image, a maximum scanning voltage of about 2 V was applied to the scanning deflector to create a 20 μm field of view on the sample surface.

No signal was observed when the bias potential of the grid and MCP was changed to -50V to confirm that the scattered helium ions and / or neutral atoms contributed little to their recorded images. The amount of noise in those images was found to be lower than the amount of noise that would be reached in the SEM images of the samples at the same current, the same number of pixels and the same total acquisition time.

Four. In the support assembly, the tips were manufactured and attached to the support assembly by the method described in Example 1, except that the two columns attached to the base of the source were pre-bent to each other as shown in FIG. The bending allowed the heating wire to be applied in a very short length. The heating wire was a polycrystalline tungsten wire having a diameter of 180 μm, as described in Example 1. For curved columns, a heating wire length of 5 mm was used. The advantage of short heating wire lengths was that as the wire length decreased, the rigidity of the wire length increased. The emission line was fixed by the usual method described in Example 1.

The increased stiffness of the short heating wire was observed by applying the same force to two different tips. Here, one tip was attached to the support assembly of the type described in Example 1, and the other tip was attached to the support assembly shown in FIG. The deflections of the two tips according to the applied force were compared. Compared to the example 1 type of support base, the support assembly of the bent columns was deflected by a 6-fold smaller amount. As a result, the natural frequency of the bent column type support assembly was about 2.5 times higher than the natural frequency of the support assembly of Example 1. In the case of a high frequency, when excited at a frequency substantially lower than the natural frequency, the support base and the tip move together (for example, with a negligible phase shift). When incorporated into a He ion microscope, the relatively small vibration of the tip in the assembly of the source of the curved column reduced the possibility that the ion microscope image could have significant image defects such as beam landing error due to the vibration of the tip. ..

The tips were prepared according to the procedure described in Example 1, except that different heating wires were used. The heating wire used in this example had a diameter approximately 25% larger than the diameter of the heating wire of Example 1. Thick heating wires were less compliant with vibrational motion, as the stiffness of the wires generally increased with increasing diameter. In addition, the thick heating wire was formed from a tungsten-rhenium alloy (74% tungsten, 26% rhenium). The alloy wire had a much higher electrical resistance than the tungsten heating wire of Example 1, and it was measured that the resistance of the entire heating wire was about 0.5 ohm. Suitable tungsten-rhenium alloy wires were obtained from Omega Engineering (Stamford, CT).

The thick heating wire increased the natural frequency of the support assembly, including the tip, from about 1.5kHz (Example 1) to about 2.2kHz (Example 1). When incorporated into a He ion microscope, the relatively low vibration of the tip in the assembly of the source equipped with this heating wire assembly can cause the ion microscope image to have considerable image defects such as beam landing error due to the vibration of the tip. Reduced sex.

6. The tip was formed by the method described in Example 1, except that the heating wire was replaced with a block of pyrolytic carbon (MINTEQ International Pyrogenics Group, Easton, PA). The columns of the source assembly were bent from each other and machined to have a parallel, flat surface. To attach the emission line, the columns were pulled apart and two pyrolytic carbon blocks were inserted between the columns. A emission line was placed between the carbon blocks so that the pillars could then be moved. The compressive force applied to the carbon block by the column held the block and emission line in place on the support assembly and prevented the emission line from moving relative to the support base. A portion of the support assembly containing the curved columns, two carbon blocks and emission lines is shown in Figure 57.

The size of the pyrolytic carbon block was chosen so that the carbon block and emission line were in a compressed state. Without the carbon blocks in place, the gap between the curved columns was 1.5 mm. The carbon blocks each had a length of 700 μm along the direction between the two curved columns. The emission line had a diameter of 250 μm.

Pyrolytic carbon blocks are oriented with respect to curved columns for maximum electrical resistance and minimum thermal conductivity (eg, the carbon plane of the pyrolytic carbon block is oriented approximately perpendicular to the line connecting the columns). ). The electrical resistance of the support assembly was measured to be 4.94 ohms at 1500 K, which was greater than the resistance of the support assembly in Example 1 (0.56 ohms). The power required to heat the tip to 1500K was 6.4W (compared to the approximately 11W required to heat the tip to 1500K in Example 1). The tip was held relatively firmly against the base of the source due to the absence of heating wire. The natural frequency of the support assembly was greater than 3 kHz.

When incorporated into a helium ion microscope, the relatively low vibration of the tip in the assembly of this source (the pyrolytic carbon blocks were added on both sides of the tip and held in place by compressive forces) is the tip of the ion microscope image. The possibility of having considerable image defects such as beam landing error due to vibration has been reduced.

7. The tip was prepared according to the procedure described in Example 1, and the characteristics of the geometric tip characteristics were determined as described in Example 1. The tip was approved for use based on the criteria of Example 1.

The tip was FIM polished using the procedure described in Example 1. Next, the tip was placed in the He ion microscope to construct it. A microscope system was constructed as described in Example 1 with the following configuration changes.

The microscopy system was configured to measure secondary electrons emitted from the sample by interacting with the incident He ions of the sample. Sample images were recorded using an MCP detector (configured similar to the detector described in Example 3).

The sample was made of steel, had a spherical shape, and had a uniform composition. The He ion beam current was 1.0 pA and the average ion energy was 20 keV. The ion beam was raster-scanned with a residence time of 10 μs per pixel. The maximum potential (about 100 V) applied to the scan deflector provided a field of view of about 1 mm on the sample surface.

An image of the sample is shown in Figure 58. The image reflects a measurement of total secondary electron emission for the sample. The image shows the improved amount of secondary electrons emitted at the right end. The increased emission was due to the increased path length of the ion beam near the sample surface. Here, the secondary electrons can escape. It was found that the amount of secondary electron emission increases in proportion to sec (α). Here, α represents the angle between the incident He ion beam and the normal of the sample surface.

Images of the second sample are shown in Figures 59A and 59B. The imaging conditions for the sample shown in FIG. 59A were as described in relation to the first sample in this example.

At an energy of 20 keV, it penetrated deep into the sample (about 100 nm) before the He ion beam was significantly branched. As a result, the edges of the sample image showed a relatively narrow and bright edge effect (eg, blowout at reduced edges). For example, the image of FIG. 59A was recorded from a He ion microscope, while the image of FIG. 59B was recorded using a standard SEM. The signals in both images result solely from the measurement of secondary electrons. In the SEM image shown in FIG. 59B, the SEM was operated under imaging conditions of an electron beam energy of 2 keV and a beam current of 30 pA.

In the He ion microscope image, bright edges were observed to be visibly narrow, which is believed to be the result of a small amount of He ion interaction on the sample surface compared to the incident electrons. Be done. Since the He ion beam enters the sample, the He ion beam remains relatively parallel. In contrast, the SEM electron beam results in a fairly wide amount of interaction directly adjacent to the sample surface. As a result, the secondary electrons generated by the incident electron beam arise from a surface region that extends several nanometers from the nominal electron beam position on the surface. As a result, the bright edge effect of the SEM is substantially wider, as can be seen by visually comparing the images in FIGS. 59A and 59B.

In order to numerically compare the bright edge effects of these two images, line scanning was performed over the common edge features of each image. The results are shown in FIGS. 67A and 67B, respectively, corresponding to FIGS. 59A and 59B. The range of line scanning was 50 pixels long and 1 pixel wide. The intensity peak of the line scan corresponding to the edge feature has a full width at half maximum (FWHM) that is 40% wider than the corresponding He ion microscope image. As mentioned above, the reduced edge width observed in the He ion microscope image is the result of the amount of small interaction of He ions on the sample surface with respect to the electrons.

8. 8. The tip was prepared according to the procedure described in Example 1, and the characteristics of the geometric tip characteristics were determined as described in Example 1. The tip was approved for use based on the criteria of Example 1.

The tip was ground with FIM according to the procedure described in Example 1. Next, the tip was placed in the He ion microscope to construct it. A microscope system was constructed as described in Example 1 with the following configuration changes.

The microscopy system was configured to measure secondary electrons emitted from the sample by interacting with the incident He ions of the sample. Sample images were recorded using an MCP detector (configured similar to the detector described in Example 3).

Various samples were measured to quantitatively determine the amount of secondary electrons emitted from many materials. Each sample consisted of a piece of flat material and was tested. A low filling rate (eg, mostly spatial) metal screen was placed on the sample at a distance of 2 mm. Using a pico ammeter (Caseray Instrument Corporation, Cleveland, OH), the current of the sample was measured by machining a groove in the surface of each sample and connecting it to the Faraday cup incorporated in each sample.

Each test began measuring the He ion current by positioning the He ion beam so that it was incident on the Faraday cup in each sample. Next, while applying a variable bias to the screen with respect to the common external grounding portion, the He ion beam was rasterized over the sample, and the secondary electrons from the sample were measured.

The focus of the He ion beam was intentionally blurred (spot size of 100 nm) to minimize any contamination or charge defects. The bias potential of the screen was gradually adjusted from -30V to + 30V, and the secondary electron current was measured for each bias potential. Each measurement was performed with a He ion beam energy of 22.5 keV and a beam current of 13 pA. The graph in FIG. 60 shows the results of the silicon sample.

On the left side of the graph with the screen negatively biased, all of the secondary electrons emitted from the sample returned to the silicon sample due to the interaction of the sample with the incident He ions. The He ion beam current and the secondary electron current were approximately equal, resulting in the production of very small amounts of free secondary electrons and scattered helium ions. On the right side of the screen, where the screen is positively biased, the interaction of the sample with the incident He ions accelerated all of the secondary electrons emitted from the sample and left the sample. The measured current of the sample was the sum of the He ion current and the secondary electron current. Based on these measurements, the amount of secondary electrons emitted for a 22.5 keV helium beam incident (normal incident) incident on a flat silicon sample is approximately (44-13) / 13 = 2.4.

Similar measurement procedures were continued for various substances under similar measurement conditions. The results are summarized in the table below.

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Their relatively large amounts of secondary electron emissions and extensive values for different materials are common in that He ion microscopic images based on the detection of secondary electrons provide an excellent way to distinguish between different substances. The observation results will be explained. As an example, FIG. 61 is a secondary electron image of the cross-shaped alignment portion on the substrate surface recorded using a helium ion microscope. A scanning voltage with a maximum amplitude of about 1.5 V was introduced into the scanning deflector to create a field of view of 15 μm on the sample. The MCP detector was placed at a distance of 10 mm from the sample and oriented parallel to the sample surface. The grid and front of the MCP were biased to + 300V with respect to the common external ground. The He ion beam current was 5 pA and the average ion energy was 27 keV. The ion beam was raster-scanned with a residence time of 150 μs per pixel.

FIG. 61B is a secondary electron image of the SEM taken for the same feature. The SEM was operated under optimal imaging conditions with an experimentally determined electron beam energy of 2 keV and a beam current of 30 pA. Other beam currents, scan speeds and beam energies have been tried, but none of them provided good contrast.

The He ion microscope image shows excellent contrast between the different materials forming the cross-shaped alignment due to the large difference in the amount of secondary electron emission of the incident He ion beam with respect to the incident electron beam. In FIG. 61A, the two substances in the cross-shaped alignment can be easily visually distinguished. However, as qualitatively observed in FIG. 61B, the two materials have similar amounts of secondary electron emissions for the incident electron beam of the SEM.

9. The tip was prepared according to the procedure described in Example 1, and the characteristics of the geometric tip characteristics were determined as described in Example 1. The tip was approved for use based on the criteria of Example 1.

The tip was ground with FIM according to the procedure described in Example 1. Next, the tip was placed in the He ion microscope to construct it. A microscope system was constructed as described in Example 1 with the following configuration changes.

The microscopy system was configured to measure secondary electrons emitted from the sample by interacting with the incident He ions of the sample. Sample images were recorded using the MCP detector (described in Example 3). Since there is a grid in front of the front end of the MCP, the front end of the MCP was biased to + 100V with respect to the common external ground. In this configuration, the MCP is capable of collecting almost all of the secondary electrons emitted from the sample by interacting with the incident He ions of the sample, except for the secondary electrons created in the positively biased region of the sample. there were. Instead of being completely emitted from the sample and detected by the MCP, those secondary electrons returned to the sample with a positive voltage bias.

The sample region was positively biased by both arriving with a positive charge and starting with a negative charge (secondary electrons) from the incident ion beam. The magnitude of the induced voltage bias on the sample for a given He ion beam current was determined by the capacitance and / or resistance of the exposed portion of the sample with respect to the peripheral portion of the sample. These differences resulted in the collection of different secondary electrons for different regions of the sample, depending on the electrostatic and / or resistance properties of the sample. The differences in the different secondary electron collections detected produced contrast in the images of the samples recorded using a He ion microscope. In this way, the electrical characteristics of the sample were determined based on the secondary electron image.

FIG. 62 shows a secondary electron image of the sample. The sample featured a set of aluminum wires deposited on the surface of the insulating substrate. A scanning voltage with a maximum amplitude of 3 V was introduced into the scanning deflector to create a field of view of 30 μm on the sample. The He ion beam current was 5 pA and the average ion energy was 26 keV. The ion beam was raster-scanned with a residence time of 100 μs per pixel.

The sample image shows a series of periodic, bright aluminum wires. In the gap between those bright lines, there is a series of dark lines. The bright line in the center of the image indicates a clear boundary, and beyond that boundary the line darkens. Based on the nature of the sample, the bright line has a low resistance path to the ground, or has a very high capacitance to the ground, so that the bright line is of the He ion beam. It was not substantially biased by the action.

The dark lines were positively biased under the influence of the He ion beam, and as a result, the secondary electrons produced there returned to the sample. To determine if this effect was due to the capacitance or resistance characteristics of the dark line, a He ion beam was received and the dark line was observed over a period of time. If this effect was actually a capacitive characteristic, the lines would get darker and darker over time.

The transition from light to dark on the central aluminum wire can suggest, for example, the presence of an electrical break on the wire. The bright part of the lower line cannot make full electrical contact with the dark part of the upper line.

FIG. 63 shows images of other samples recorded using the measurement configuration described above. The sample contains a wire formed of copper on a silicon substrate and other features. The smallest feature is the form of the character ("DRAIN"). The positive potential bias of the feature increased through image acquisition, as evidenced by the observations that the top of each letter looks bright but the bottom of each letter looks dark. Raster scanning of this image proceeded from top to bottom. As a result, the bias mechanism on the surface features of the sample is primarily capacitive.

Ten. The tip was prepared according to the procedure described in Example 1, and the characteristics of the geometric tip characteristics were determined as described in Example 1. The tip was approved for use based on the criteria of Example 1.

The tip was ground with FIM according to the procedure described in Example 1. Next, the tip was placed in the He ion microscope to construct it. A microscope system was constructed as described in Example 1 with the following configuration changes.

The microscopy system was configured to measure secondary electrons emitted from the sample by interacting with the incident He ions of the sample. Sample images were recorded using the MCP detector (described in Example 3). Since there is a grid in front of the front end of the MCP, the front end of the MCP was biased to + 300V with respect to the common external ground. In this configuration, almost all of the measurement signals originated from secondary electrons. This was verified by observing that the front end of the MCP was biased to -300V without changing the MCP increase and the measurement signal was reduced to near zero.

A scanning voltage with a maximum amplitude of 3 V was introduced into the scanning deflector to create a field of view of 30 μm on the sample. The He ion beam current was 10 pA and the average ion energy was 22 keV. The ion beam was raster-scanned with a residence time of 100 μs per pixel.

Samples containing three distinct layers were imaged. The top metal layer consisted of copper and patterned wires. The next layer was composed of a dielectric. The bottom layer was composed of other layers of different pattern formation made of copper. An image of the sample is shown in FIG. The image shows the pattern of the top metal layer overlaid on the features of the gray image corresponding to the metal layer at the bottom (inner layer surface) in bright white. The inner surface metal layer appears dim and slightly blurry in the image.

The measurement signal was the result of secondary electrons generated on the sample surface by both scattered He ions and neutral He atoms. This assessment was verified by negatively biasing the MCP and screen, noting that little signal was detected. Secondary electrons emitted from the sample by interaction with the incident He ions of the sample produced an image of the surface metal layer in FIG. The image of the inner metal layer is the generated He ions that enter the sample and neutralize. Neutral He atoms are scattered from the layers on the inner surface, and some of them return to the surface where they leave to produce secondary electrons. This describes a darker and blurry image of the features of the inner layer surface.

11. 11. The tip was prepared according to the procedure described in Example 1, and the characteristics of the geometric tip characteristics were determined as described in Example 1. The tip was approved for use based on the criteria of Example 1.

The tip was ground with FIM according to the procedure described in Example 1. Next, the tip was placed in the He ion microscope to construct it. A microscope system was constructed as described in Example 1 with the following configuration changes.

The microscopy system was configured to measure secondary electrons emitted from the sample by interacting with the incident He ions of the sample. Sample images were recorded using the MCP detector (described in Example 3). Since there is a grid in front of the front end of the MCP, the front end of the MCP was biased to + 300V with respect to the common external ground. In this configuration, almost all of the measurement signals originated from secondary electrons. This was verified by observing that the front end of the MCP was biased to -300V without changing the MCP increase and the measurement signal was reduced to near zero.

A scanning voltage with a maximum amplitude of 15 V was introduced into the scan deflector to create a field of view of 150 μm on the sample. The He ion beam current was 10 pA and the average ion energy was 21.5 keV. The ion beam was raster-scanned with a residence time of 100 μs per pixel.

The imaged sample consisted of a welded piece of tungsten. Tungsten was heated above its melting point and then cooled to form a clear crystallographic domain with abrupt boundaries between the grains. The sample was imaged by measuring the secondary electrons emitted from the sample by the interaction with the incident He ions of the sample.

An image of the sample is shown in FIG. The image clearly shows bright and dark particles. Overlaid on this background is a bright image feature over some particles. The bright features correspond to local embossed patterns on the surface, which enhances the generation of secondary electrons by the topographical effects disclosed herein. The contrasting image intensities of the various grains were due to the relative orientation of the crystal domains with respect to the incident He ion beam. When the tungsten lattice of a particular particle was oriented so that the He ion beam was oriented almost parallel to the low index crystallographic direction, the scattering probability on the surface was low, so the ion beam penetrated deep into the particle. As a result, the amount of secondary electrons emitted on the surface of the material was relatively low, and the particles appeared dark in the image. On the contrary, when the tungsten lattice of a specific particle was oriented so that the He ion beam was incident in the crystallographic direction with a high index, the scattering probability on the particle surface was high. As a result, the amount of secondary electrons emitted on the surface of the material was relatively high, and the particles appeared bright in the image.

12. The tip was prepared according to the procedure described in Example 1, and the characteristics of the geometric tip characteristics were determined as described in Example 1. The tip was approved for use based on the criteria of Example 1.

The tip was ground with FIM according to the procedure described in Example 1. Next, the tip was placed in the He ion microscope to construct it. A microscope system was constructed as described in Example 1 with the following configuration changes.

The microscopy system was configured to measure He ions and neutral He atoms scattered from the sample in response to the incident He ions. Sample images were recorded using the MCP detector (described in Example 3). Since there is a grid in front of the front end of the MCP, the front end of the MCP was biased to -100V with respect to the common external ground. In this configuration, the secondary electrons do not reach the MCP due to the negatively applied potential bias. The signal measured by the MCP arises from scattered He ions and neutral He atoms incident on the anterior surface of the MCP.

A scanning voltage with a maximum amplitude of 15 V was introduced into the scan deflector to create a field of view of 150 μm on the sample. The He ion beam current was 10 pA and the average ion energy was 21.5 keV. The ion beam was raster-scanned with a residence time of 100 μs per pixel.

The imaged sample was a tungsten-welded sample examined in Example 11. As before, the welded tungsten contained a well-defined crystallographic domain with sharp boundaries between the particles.

The sample was imaged by detecting the abundance of He atoms and He ions incident on the MCP. An image of the sample obtained by this measurement procedure is shown in FIG. 68. The image shows both bright and dark particles. For a particular crystal grain, when the tungsten lattice of the grain was oriented so that the He ion beam was incident along a relatively low index crystallographic direction, the probability of He scattered on the grain surface was low. As a result, the ions penetrated deep into the particles before scattering occurred. As a result, He ions (or He neutral atoms produced when He ions combine with electrons in the sample) are unlikely to come out of the sample and be detected by the MCP detector. In the recorded image, the particles with those properties appeared dark.

On the contrary, when the tungsten lattice of a specific particle was oriented so that the He ion beam was incident along a crystallographic direction with a relatively high index, the probability of He scattered on the particle surface was relatively high. As a result, the entry of He ions into the sample before scattering was relatively shallow on average. As a result, He ions and / or neutral He atoms were relatively likely to come out of the sample surface and be detected by the MCP detector. Therefore, the particles having a high index crystal orientation with respect to the incident He ion beam appeared bright in the image shown in FIG. 68.

With reference to the image shown in FIG. 65, the topographic information of the image of FIG. 68 was significantly reduced as the image was recorded based on scattered He particles rather than secondary electrons. In particular, the series of bright lines appearing in the image of FIG. 65 have been largely removed from the image of FIG. 68. The lack of topographic information can make it relatively easy to interpret the image of FIG. 68, in particular the crystallographic properties (relative orientation, etc.) of the crystalline domain in the sample using the measured intensities of FIG. 68. ) Can be confirmed quantitatively.

13. The tip was prepared according to the procedure described in Example 1, and the characteristics of the geometric tip characteristics were determined as described in Example 1. The tip was approved for use based on the criteria of Example 1.

The tip was ground with FIM according to the procedure described in Example 1. Next, the tip was placed in the He ion microscope to construct it. A microscope system was constructed as described in Example 1 with the following configuration changes.

The microscopy system was configured to measure He ions and neutral He atoms scattered from the sample in response to the incident He ions. A detector (small MCP) was attached to the shaft of the motor. Copper tape was used to cover the anterior surface of the MCP, limiting the measurement of He ions and / or neutral atoms by the MCP. The small round holes in the copper tape allowed the scattered ions and / or neutral atoms to reach the MCP only if they contained scattered ions and / or neutral atoms in a narrow angular range. In this example, measurements of He ions and / or neutral atoms were limited to a solid angle of 0.01 steradian. Since the copper tape and the front surface of the MCP were biased to -100V with respect to the common external ground, secondary electrons did not enter the MCP detector.

The detector was placed at a distance of 30 mm from the sample. The motor made it possible to detect He ions and / or neutral atoms emitted from the sample surface in different angular ranges due to the rotation of the MCP with respect to the sample. Typically, for example, the motor allowed the MCP to rotate up to 180 °.

The sample was a copper ball with a diameter of about 1 mm. The motor was placed relative to the sample so that the sample was placed along the axis of the motor shaft. Copper ball samples provided scattered He ions and neutral He atoms at a wide range of angles, depending on the shape of the sample surface when irradiated with a He ion beam. That is, by scanning the incident He ion beam over the sample surface, various different incident angles (for example, the angle between the He ion beam and the normal of the sample surface) can be realized. For example, at the center of the copper ball, the incident angle of the He ion beam is 0 °. At the edge of the ball (observed from the viewpoint of the He ion beam), the angle of incidence is about 90 °. At an intermediate position between the center and the edge of the copper ball, the angle of incidence is about 30 ° from the sample trigonometry.

The sample was placed under the He ion beam and the detector was placed on the sample as described above. The He ion beam current was 15 Ap and the average ion energy in the He ion beam was 25 keV. A maximum voltage of 100 V was applied to the scan deflector to achieve a field of view of 1 mm on the sample surface. The distance from the second lens of the microscopy system to the sample (eg, working distance) was 75 mm. This provided enough space for the MCP to rotate relative to the sample.

The measurement was performed by recording an image of a copper ball while sweeping the detector in a hemispherical arc shape over an angle range of 180 ° with respect to the sample. The He ion beam was effective in dividing the sample surface into both sides, and the convex surface of the copper ball allowed only scattered He ions and neutral He particles to be detected from the side where the detector was placed. As a result, in FIG. 69A, the intensity profile of the sample image was crescent-shaped in the bright area on the left corresponding to the position of the detector. The right side of the sample was relatively dark because scattered He ions and neutral He particles came out of the sample surface in a direction that could not be measured by the detector.

A series of images of the sample was recorded by increasing the angle of the detector between each image. A total of 20 sample images were obtained over the scanning range of the detector. The particular image did not provide useful information because the detector was positioned to block the incident He ion beam and prevented the He ion from entering the sample surface. The images shown in FIGS. 69B and 69C correspond to the images recorded by the detector located approximately directly above the sample and the detector located to the right of the sample, respectively. In FIG. 69C, a crescent-shaped intensity profile similar to the intensity profile observed in FIG. 69A is observed.

Based on the quantitative examination of the recorded images, it was clear that topographical information about the sample could be determined from the images measured by the off-axis detector (eg, FIGS. 69A and 69B). The information obtained from these measurements can be combined with the secondary electron measurements of the sample, for example, whether the image contrast observed in the secondary electron image is due to the surface topography of the sample, or the charge or material composition of the sample, etc. It was possible to confirm whether it was due to other contrast mechanisms. In the case of the detector at a known position, it was possible to distinguish the ridges on the sample surface from the dents based on the recorded image. In addition, using the acceptance angle of a small detector and the known detector position for each recorded image, the shadow length of the surface feature portion in the image is measured, and the incident He ion beam is known with respect to the surface feature portion. By using the angle, it was possible to determine quantitative surface embossment (eg, maximum) information.

The sample image also revealed that, depending on the orientation of the detector with respect to the sample, certain edges of the sample exhibited a bright edge effect while other edges exhibited a dark edge effect (see, eg, FIG. 69A). .. This information was used in the design of detectors configured to reduce the measurement of topographic information from the sample. The detector design balanced the detection angles and provided a nearly uniform edge effect. As a result, the image of the sample such as a copper ball looks uniformly bright in a state where the strength varies due to the difference in the substance of the sample.

Image data recorded from the sample was analyzed to determine how the intensity of the selected area on the sample surface changed as the detector was scanned. The variation in intensity is due to the angular distribution of He ions and He neutral atoms emanating from the sample surface, and this analysis provided information on the angular distribution, sometimes referred to as the emission lobe.

FIG. 70A shows an image of the sample recorded using an incident He ion beam with a nearly axial detector, i.e. the detector measured scattered He ions and neutral He atoms at an angle of approximately 0 °. The area of the sample surface shown in the rectangular box was separated by a series of images and underwent further analysis. In the diagram shown in FIG. 70B, the thick horizontal lines represent the sample surface graphically and the thin vertical lines represent the incident He ion beam. The points represent the average measured intensities of scattered He ions and neutral He atoms at various detector positions. The points are represented in polar coordinates, and the origin of the polar coordinates is the incident point of the He ion beam on the sample surface. The angular position of a predetermined point corresponds to the angular position of the detector, and the radial distance from the origin to each point is represented by the average measured intensity at the angular position of the specific detector. The individual sample images corresponded to different detector positions, and the images were analyzed to provide the angular intensity data shown in FIG. 70B. Each point corresponds to an image recorded at a different detector position.

The pole arrangement of points forms a diagram of the emission lobe. The diagram is approximately round in shape (except for a few missing points where the He ion beam is blocked by the detector) and corresponds to a cosine-type distribution with respect to the origin.

In Figure 71A, the sample is surrounded by an overlaid rectangular box showing different regions of the sample surface analyzed using multiple sample images to determine the angular intensity distribution of scattered He ions and neutral atoms from the sample. The image of is shown. In this case, the scattering angle or emission angle was about 40 ° with respect to the incident He ion beam.

The polar coordinates of the angular emission intensity shown in FIG. 71B were configured as described for FIG. 70B above. The lobe shape at this angle showed that the scattering / emission preferentially directed away from the incident He ion beam.

This analysis is repeated in different regions of the sample surface (corresponding to different angles) to build a relatively complete image of the distribution of scattered He ions and neutral He atoms depending on the angle of the copper ball sample. did.

14. The tip was prepared according to the procedure described in Example 1, and the characteristics of the geometric tip characteristics were determined as described in Example 1. The tip was approved for use based on the criteria of Example 1.

The tip was ground with FIM according to the procedure described in Example 1. Next, the tip was placed in the He ion microscope to construct it. A microscope system was constructed as described in Example 1 with the following configuration changes.

The microscopy system was configured to measure He ions and neutral He atoms scattered from the sample in response to the incident He ions. Sample images were recorded using the MCP detector (described in Example 3). Since there is a grid in front of the front end of the MCP, the front end of the MCP was biased to -300V with respect to the common external ground. In this configuration, the secondary electrons do not reach the MCP due to the negatively applied potential bias. The signal measured by the MCP arises from scattered He ions and neutral He atoms incident on the anterior surface of the MCP. From the viewpoint of the sample, MCP detected He ions and He atoms from solid angles within about 1.8 steradians. The solid angle was azimuthally symmetric with respect to the incident beam as shown in FIG.

From Example 13, the bright and dark edge effects observed for a copper ball sample are the topo of the measurement signal when used to image the sample by measuring scattered He ions and / or neutral He atoms. It provided information on the design and composition of the detector, which reduced the amount of grammar information and also accurately reflected differences in material composition rather than differences in local surface topography of the sample. For the MCP detector shown in FIG. 66, the reduction of topography information in the images formed based on the measurements of scattered He ions and neutral He atoms is when the MCP is located at a working distance of about 25 mm from the sample. It was observed.

Samples containing different substances could then be imaged, and those substances visually distinguished each other accurately. Samples containing four different substances (nickel-based layer, carbon coating, copper lattice, gold wire) were imaged using a He ion microscope. The He ion beam current was 1.1 pA and the average He ion energy was 18 keV. A maximum voltage of 4 V was applied to the scanning deflector to achieve a field of view of 40 μm on the sample surface. The total image collection time was 90s.

The obtained image is shown in FIG. 72. Different intensities were observed for each of the four different substances in the sample. This is a result of the fact that the scattering probability of He ions incident on a particular substance is determined by the atomic number of the substance. In FIG. 72, even substances with similar atomic numbers can be distinguished. For example, copper (atomic number 29) is visually distinguishable from nickel (atomic number 28).

FIG. 73 shows an image of a sample containing a copper layer beneath a silicon wafer with the oxide layer above the silicon wafer. Images were measured using a He ion microscope system configured for the detection of scattered He ions and neutral He atoms, as described earlier in this example. The sample contains features of the surface structure created by directing the laser incident on the sample surface. The laser caused an explosive eruption of the underlying copper layer. Visual inspection of the image reveals image contrast (eg, variation in image intensity) due to different substances present in the sample. From images such as the image of FIG. 73, the distribution of different substances in the sample can be determined.

15. 15. The tip was prepared according to the procedure described in Example 1, and the characteristics of the geometric tip characteristics were determined as described in Example 1. The tip was approved for use based on the criteria of Example 1.

The tip was ground with FIM according to the procedure described in Example 1. Next, the tip was placed in the He ion microscope to construct it. A microscope system was constructed as described in Example 1 with the following configuration changes.

The microscopy system was configured to measure photons emitted from the sample in response to incident He ions. The image of the sample was constructed from the signal generated by a photomultiplier tube (R6095 type, Hamamatsu Photonics Co., Ltd., Toyooka, Japan). Photomultiplier tubes had a straight window, relatively high quantum efficiency, and a wide range of spectral sensitivities from 200 nm to 700 nm. Photomultiplier tubes were operated with signal gains that could be increased up to 1200 V or until the output signal reached the white noise level of the signal chain without being oversaturated. A photomultiplier tube was placed at a distance of 15 mm from the sample and oriented to face the sample. In this configuration, the tube defined a solid angle range of about 2 steradians.

A sample of sodium chloride (NaCl) was imaged using a photomultiplier tube detector. For that measurement, the He ion beam current was 10 pA and the average He ion energy was 25 keV. The sample was raster scanned with a residence time of 500 μs per pixel. A maximum voltage of 150 V was applied to the scanning deflector to obtain a field of view of 1.35 mm on the sample surface.

An image of the sample is shown in FIG. 74. Image contrast (eg, variation in image intensity) is apparent in different NaCl crystals. Photons can be produced in a sample by two different mechanisms. First, photons can be produced by a process similar to the cathode emission observed in SEM images. In this mechanism, the atoms of the sample are excited to a higher energy state. During the subsequent deexcitation process, it emits photons. When the He ion from the incident beam returns to the lower energy state, it emits a photon.

Other samples that are irradiated with He ions and whose emitted photons are detected include plastics, scintillators and organic substances.

16. The tip was prepared according to the procedure described in Example 1, and the characteristics of the geometric tip characteristics were determined as described in Example 1. The tip was approved for use based on the criteria of Example 1.

The tip was ground with FIM according to the procedure described in Example 1. Next, the tip was placed in the He ion microscope to construct it. A microscope system was constructed as described in Example 1 with the following configuration changes.

Bias the tip to + 19kV with respect to the extraction section and 2 × 10 near the tip^-5He gas was introduced at the pressure of Torr. A Faraday cup is placed beyond the second lens, and using an alignment deflector, virtually all of the He ions generated from one of the tip trimeric atoms are squeezed (600 μm in diameter, 370 mm from the tip). The beam was focused so that it passed through (located) and substantially all of the He ions generated from the other two trimeric atoms were blocked by the aperture. After passing through the aperture, the first lens focused the He ion beam into the Faraday cup. In this configuration, the astigmatism corrector, scanning deflector and second lens were off.

Using a pico ammeter with a Faraday cup (Type 487, Keithley Instruments, Cleveland, OH), it was measured that the total He ion current generated from the tip atom was 300 pA. The Faraday cup was a cylindrical metal cup with a depth-to-diameter ratio of about 6 to 1.

After that, I stopped the first lens. Each He ion generated at the tip continued to travel in a straight line and separated from the tip. The aperture interfered with most of the He ion beam, causing only its small central portion to descend further through the rest of the ion barrel. The portion of the He ion beam passing through the diaphragm was detected by a Faraday cup, and a measured He ion current of 5 pA passing through the diaphragm was obtained. Next, the angular intensity of the He ion beam was calculated by dividing the He ion beam current (5 pA) passing through the aperture by the solid angle of the aperture from the viewpoint of the tip. The half-width of the cone formed by the tip top and the aperture is tan^-1(0.300/370)=0.046°=8.1×10^-4Calculated as radians. The corresponding solid angle is 2.1 x 10^-6Calculated as steradian (sr). Based on the solid angle, the angular intensity of the He ion beam was determined to be 2.42 μA / sr.

The brightness of the He ion source was determined from the angular intensity of the He ion beam and the size of the virtual source. The virtual source size was estimated by examining the FIM image of the tip recorded while polishing the tip. From this image, it was clear that the individual ionization discs corresponding to the tip trimer atoms did not overlap. Furthermore, it was known from the crystallography of tungsten that trimer atoms are separated by about 5 angstroms. Therefore, the actual ionized disc was estimated to have a diameter of about 3 angstroms.

The virtual source size is generally smaller than the actual ionization region. Once the He ions have crossed the electric field region of the ion source (eg, the region near the tip and extraction section), virtual by the general procedure described above by back-projecting the asymptotic orbit of 100 He ions. The source size was determined. The back-projected orbits moved in close proximity to each other until the back-projected orbits passed through the most dense spatial regions of each other, after which they diverged again. We defined the diameter of the circle with the closest spacing of the back-projected orbits as the virtual source size.

We used a value of 3 angstroms as the upper limit of the diameter of the virtual source. If the microscope is configured so that only a portion of the He ion beam generated from a single tip atom can pass through the diaphragm, the virtual source size can be significantly reduced. Luminance is the angular intensity of the virtual source size area A (A = π (D / 2))²) Divided by). The brightness of the ion source is 3.4 x 10⁹A / cm²It was sr.

The reduced brightness was calculated by dividing the brightness by the voltage used to draw the beam (eg, the voltage bias applied to the tip). The voltage at the tip to the extraction part is 19kV, and the reduction brightness is 1.8 × 10.⁹A / m²It was srV.

Etandu is a measure of the product of the virtual source size of a He ion beam and its angular divergence (solid angle). Using the determined brightness, Etandu is 1.5x10^-21cm²Decided to be sr.

The reduced etandu is obtained by multiplying the etandu by the He ion beam voltage. Based on the calculated etandu, the reduced etandu is 2.8 × 10 (using a tip bias voltage of + 19 kV).^-17cm²Decided to be srV.

17. 17. The tip was prepared according to the procedure described in Example 1, and the characteristics of the geometric tip characteristics were determined as described in Example 1. The tip was approved for use based on the criteria of Example 1.

The tip was ground with FIM according to the procedure described in Example 1. Next, the tip was placed in the He ion microscope to construct it. A microscope system was constructed as described in Example 1 with the following configuration changes.

The microscopy system was configured to measure secondary electrons using an ET detector. The detector was placed at a distance of 10 mm vertically (parallel to the He ion beam) from the sample, moved 25 mm laterally from the sample, and tilted towards the sample. The ET screen was biased to a potential of + 300V with respect to the common external ground.

The He ion beam current was 1 pA and the average ion energy in the beam was 22 keV. A He ion beam was raster-scanned over the sample surface with a residence time of 100 μs per pixel. A maximum voltage of 100 mV was applied to the scan deflector to obtain a 1000 nm field of view on the sample surface.

The sample contained island-shaped gold particles formed on the surface of the carbon substrate and was obtained from Structure Probe Incorporated (Westchester, PA). An image of the sample recorded by the above measurement configuration is shown in FIG. 75. The region of the sample image shown by the rectangle superimposed on the image of FIG. 75 was selected to examine the quality of the edge contrast observed with a He ion microscope. The area specified by the rectangle contains a nearly vertical gold edge. The area contains 20 columns, each with 57 pixels. An enlarged view of the selected area is shown in FIG.

Each column of the selected image area was analyzed individually as follows. First, to reduce noise, a MathCAD kernel smoothing function (PTC Incorporated, Needam, MA) was used to smooth each column with a Gaussian nucleus with a bandwidth of 3 pixels. FIG. 77 shows a graph in which the image intensity values of one line (line # 14) before smoothing (points) and after smoothing (curve) are plotted. The vertical axis corresponds to the image intensity that varies from 0 (black) to 255 (white). The horizontal axis corresponds to a pixel number that varies from 0 (left edge) to 57 (right edge).

For each intensity line scan of the selected image region, the center of the left-right light-dark transition was determined by determining the minimum value of the first derivative of the intensity line scan. For the edge having a left-right light-dark transition, the center of the transition was found by determining the maximum value of the first derivative of the intensity line scan.

Each line was then arranged to contain exactly 21 pixels. Trimming operations such as the transition point, 10 pixels before the transition point, and 10 pixels after the transition point were continued on each line. The intensity values for the first 5 pixels of each trimmed line were combined and averaged, and the average was regarded as the 100% value. The intensity values for the last 5 pixels of each trimmed line were combined and averaged, and the average was regarded as the 0% value. Next, the smoothed data from each line scan was readjusted in terms of 100% and 0% values. The data readjusted from FIG. 77 is shown in FIG. 78.

With reference to FIG. 78, the 75% and 25% values were determined based on the 0% and 100% values. The spot size of the He ion beam was determined substantially as the distance interval along the horizontal axis between the 25% and 75% values. Based on the data in FIG. 78, it was determined that the spot size was 3.0 pixels. The pixel size was converted to nanometers using the known field of view in the measurement configuration and the number of pixels in the image. For this measurement, the field of view was 641 nm and there were 656 pixels across the field of view. Therefore, it was determined that the spot size of the He ion beam is 2.93 nm. This was repeated for each of the 20 lines in the selected image region and the results were averaged to give an average He ion beam spot size of 2.44 nm.

18. 18. The tip was prepared according to the procedure described in Example 1, and the characteristics of the geometric tip characteristics were determined as described in Example 1. The tip was approved for use based on the criteria of Example 1.

The tip was ground with FIM according to the procedure described in Example 1. Next, the tip was placed in the He ion microscope to construct it. A microscope system was constructed as described in Example 1 with the following configuration changes.

The microscopy system was configured to measure scattered He ions and neutral He atoms emitted from the sample surface in response to incident He ions. The MCP detector described in Example 3 was placed 10 mm from the sample. A potential bias of 0 V was applied to the MCP grid and the front surface with respect to the external ground.

The He ion beam current was 1 pA and the average He ion beam energy was 26 keV. A He ion beam was raster-scanned over the sample surface with a residence time of 100 μs per pixel. A maximum potential of 1.30 V was applied to the scanning deflector to obtain a field of view of 13 μm on the sample surface.

A sample containing a silicon wafer substrate with surface features formed of polysilicon, known as Metrocal, was obtained from Metroboost (Santa Clara, CA). The sample was oriented so that the He ion beam was incident at an angle perpendicular to the sample surface. Since the sample was biased to + 19.4 kV with respect to the common external ground, the He ions in the incident ion beam arrived at the sample with a landing energy of 6.6 keV. A large electric field between the sample and the MCP detector prevented secondary electrons from reaching the detector. Virtually all of the secondary electrons emitted from the sample returned to the sample surface under the influence of the electric field. As a result, the MCP detector measured scattered He ions and neutral atoms. By the time the neutral He atom measured by the detector reached the MCP, the neutral He atom was accelerated to a maximum energy of 26 keV.

FIG. 79 shows an image of a sample recorded using the measurement configuration described above. The various features on the sample surface are relatively uniform and have a measured strength that is different from the strength of the substrate. Visual inspection of the edges of surface features is free of obvious bright edge effects (eg edge blowout) that can lead to saturation of the signal chain and make it difficult to find the exact location of the edges. To clarify. In addition, there is no visual evidence of charge defects on the sample surface. If such defects are present, they will appear as voltage contrast in the image.

Figure 80 shows a horizontal line scan through one of the surface features of the sample. The horizontal axis of the line scan indicates the pixel number, and the vertical axis indicates the measured image intensity at a specific pixel. For comparison, the same sample was imaged at a magnification of 30,000 x (corresponding to a field of view of about 13 μm) at a Schottky field emission SEM (AMRAY 1860) with a beam energy of 3 keV and a beam current of 30 pA. The obtained image is shown in FIG. 81, and a horizontal line scan through the same features as scanned in FIG. 80 is shown in FIG. 82.

The line scan of FIG. 82 showed a noticeable bright edge effect, and the signal chain at the edges of the imaged surface features was almost saturated. In the body of the surface feature, the SEM line scan does not show a relatively uniform steady-state intensity level. Instead, the strength level in the body of the feature is reduced or increased everywhere except for a small area in the center of the feature. Finally, the asymmetry of the SEM line scan indicates that time-dependent charging of the surface features occurs during irradiation by the SEM. In contrast, line-scanned images of surface features recorded by detecting scattered He ions and neutral He atoms show significantly reduced edge effects and no obvious charge defects.

In addition, multiple measurements of specific feature areas on the sample surface could be performed. When multiple measurements of the feature section were performed, it was possible to confirm the statistical data on the dimensions of the feature section. For example, the average feature width, the standard deviation of the feature width, and / or the average and standard deviation of the positions of the first and / or second edges in the feature were measured. In addition, the position of the edge of one or more feature portions was analyzed using the Fourier method, and the spectrum of the spatial wavelength corresponding to the shape of the edge was determined.

19. Measurement of topography information and crystal information from the sample In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope has a FOV of 100 μm on the sample surface.²Is configured to irradiate a He ion beam with a beam current of 1 pA, an average ion energy of 20 keV and a beam spot size of 0.1% of the FOV on the sample surface.

In order to measure crystal information from the sample, the He ion beam is raster-scanned over the FOV region of the sample surface in discontinuous steps. An image of scattered He ions from the sample surface at each stage is captured using a two-dimensional detector. Each two-dimensional image corresponds to the Kikuchi pattern at a specific position on the sample surface. Based on the Kikuchi pattern, the crystal structure, lattice spacing, and crystal orientation of the sample at this position can be determined. By measuring the Kikuchi pattern in discontinuous steps throughout the FOV, a complete map of the crystal structure on the sample surface can be obtained.

To measure the topographic information from the sample, the detector is configured to measure the total intensity of secondary electrons from the sample produced in response to the incident He ion beam. The He ion beam is raster-scanned over the entire FOV region of the sample surface in a discontinuous step, and the total intensity of secondary electrons is measured according to the position of the He ion beam on the sample surface. Next, the measured crystal information is used to remove the contribution to the secondary electron intensity measurement caused by the variation in the crystal structure of the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values, where the gray level at a particular image pixel is the secondary electron at the He ion beam position on the corresponding sample. It is determined by the correction strength. Topographical information is provided by the image and shows the surface embossment pattern of the sample in the FOV.

20. Measurement of topography information and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19.

In order to measure crystal information from the sample, the He ion beam is raster-scanned over the FOV region of the sample surface in discontinuous steps. Using a detector, the total abundance of scattered He ions according to the position of the He ion beam on the sample surface is measured. A grayscale image of the sample is constructed using the measured total abundance values, where the gray level at a particular image pixel is the measured abundance of He at the He ion beam position on the corresponding sample. Determined by the total. Crystal grains that are differently oriented on the sample surface have different amounts of scattered He ions released, and the image shows differently oriented crystal grains as varying gray levels. Using the information in the image, the crystal grains and grain boundaries on the sample surface can be confirmed.

To measure the topographic information from the sample, the total secondary electron intensity is measured as described in Example 19. Next, the measured crystal information is used to remove the contribution to the secondary electron intensity measurement caused by the variation in the crystal structure of the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values, where the gray level at a particular image pixel is the secondary electron at the He ion beam position on the corresponding sample. It is determined by the correction strength. Topographical information is provided by the image and shows the surface embossment pattern of the sample in the FOV.

21. Measurement of topography information and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19.

In order to measure crystal information from the sample, the He ion beam is raster-scanned over the FOV region of the sample surface in discontinuous steps. Using a detector, the total abundance of scattered He ions according to the position of the He ion beam on the sample surface is measured. A grayscale image of the sample is constructed using the measured total abundance values, where the gray level at a particular image pixel is the measured abundance of He at the He ion beam position on the corresponding sample. Determined by the total. Crystal grains that are differently oriented on the sample surface have different amounts of scattered He ions released, and the image shows differently oriented crystal grains as varying gray levels. Crystal grains and grain boundaries on the sample surface can be confirmed using the image information. After confirming the grain boundaries on the sample surface, scan the He ion beam from one particle on the sample surface to another. An image of scattered He ions from the sample surface is captured using a two-dimensional detector at each position of the He ion beam. Each two-dimensional image corresponds to a Kikuchi pattern for a particular crystal grain on the sample surface. Based on the Kikuchi pattern, the crystal structure, lattice spacing, and crystal orientation of the particles can be determined. By measuring a single Kikuchi pattern of each particle rather than each pixel across the FOV, a complete map of the crystal structure on the sample surface can be obtained in a short amount of time.

To measure the topographic information from the sample, the total secondary electron intensity is measured as described in Example 19. Next, the measured crystal information is used to remove the contribution to the secondary electron intensity measurement caused by the variation in the crystal structure of the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values, where the gray level at a particular image pixel is the secondary electron at the He ion beam position on the corresponding sample. It is determined by the correction strength. Topographical information is provided by the image and shows the surface embossment pattern of the sample in the FOV.

22. Measurement of topography information and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. Crystal information from the sample is measured as described in Example 19.

To measure the topographic information from the sample, the detector is configured to measure the total intensity of secondary electrons from the sample produced in response to the incident He ion beam. The sample is tilted relative to the He ion beam, so that the He ion beam is incident at an angle that is not perpendicular to the sample surface. The He ion beam is rasterly scanned over the entire FOV region of the sample surface in a discontinuous step, and the total intensity of secondary electrons is measured according to the position of the He ion beam on the sample surface. Next, the measured crystal information is used to remove the contribution to the secondary electron intensity measurement caused by the variation in the crystal structure of the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values, where the gray level at a particular image pixel is the secondary electron at the He ion beam position on the corresponding sample. Determined by the corrected total intensity. Topographical information is provided by the image and shows the surface embossment pattern of the sample in the FOV. Tilt the sample with respect to the He ion beam can reveal topographic information that would otherwise remain hidden if the He ion beam only enters the sample surface at a vertical angle.

Optionally, the tilt of the sample can then be adjusted so that the He ion beam is incident at different non-perpendicular angles to the sample surface, causing the He ion beam to be discontinuous over the entire FOV region of the sample surface. Raster scan in steps. The total intensity of secondary electrons is measured according to the position of the He ion beam on the surface of the sample, and the measured crystal information is used to contribute to the measurement of secondary electron intensity resulting from variations in the crystal structure of the sample. remove. Using the corrected total secondary electron intensity values, a second grayscale image of the sample corresponding to the second non-vertical incident angle of the He ion beam is constructed, where the gray level at a particular image pixel is It is determined by the corrected total intensity of secondary electrons at the He ion beam position on the corresponding sample. Next, quantitative three-dimensional topography information about the sample surface can be determined by using a combination of information from two images measured at different He ion beam incident angles.

23. Measurement of topography information and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. Crystal information from the sample is measured as described in Example 20.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 22. Using the measured crystal information, the contribution to the secondary electron intensity measurement caused by the variation in the crystal structure of the sample is removed at each incident angle of the ion beam. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 22. Next, quantitative three-dimensional topography information about the sample surface can be determined by using a combination of information from two images measured at different He ion beam incident angles.

24. Measurement of topography information and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. Crystal information from the sample is measured as described in Example 21.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 22. Using the measured crystal information, the contribution to the secondary electron intensity measurement caused by the variation in the crystal structure of the sample is removed at each incident angle of the ion beam. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 22. Next, quantitative three-dimensional topography information about the sample surface can be determined by using a combination of information from two images measured at different He ion beam incident angles.

25. Measurement of topography information and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. Crystal information from the sample is measured as described in Example 19.

To measure topographic information from a sample, two or more detectors, each oriented at a different angle and position with respect to the sample, have the total intensity of secondary electrons from the sample produced in response to the incident He ion beam. Is configured to measure. The He ion beam is rasterly scanned over the entire FOV region of the sample surface in a discontinuous step, and each detector measures the total intensity of secondary electrons according to the position of the He ion beam on the sample surface. The measured crystal information is used to remove the contribution to secondary electron intensity measurement at each detector resulting from variations in the crystal structure of the sample. Using the corrected total intensity values, a series of grayscale images was constructed for the sample, where each image corresponds to one of the detectors, where the gray levels at a particular pixel in a particular image correspond. It is determined by the corrected total intensity of secondary electrons at the position of the He ion beam on the sample. Next, the information from the images measured by the plurality of detectors can be used in combination to determine the quantitative three-dimensional topography information about the sample surface.

26. Measurement of topography information and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. Crystal information from the sample is measured as described in Example 20.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 25. The measured crystal information is used to remove the contribution to secondary electron intensity measurement at each detector resulting from variations in the crystal structure of the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 25. Next, the information from the images measured by the plurality of detectors can be used in combination to determine the quantitative three-dimensional topography information about the sample surface.

27. Measurement of topography and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. Crystal information from the sample is measured as described in Example 21.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 25. The measured crystal information is used to remove the contribution to secondary electron intensity measurement at each detector resulting from variations in the crystal structure of the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 25. Next, the information from the images measured by the plurality of detectors can be used in combination to determine the quantitative three-dimensional topography information about the sample surface.

28. Measurement of topography and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. Crystal information from the sample is measured as described in Example 19.

In order to measure the topographic information from the sample, a detector configured to measure He ions is positioned to detect He ions scattered from the sample surface at a large scattering angle. The He ion beam is rasterly scanned over the entire FOV region of the sample surface in a discontinuous step, and the total abundance of He ions according to the position of the He ion beam on the sample surface is measured by a detector. A grayscale image of the sample is constructed using that total abundance value, where the gray level at a particular image pixel is the total measurement presence of scattered He ions at the He ion beam position on the corresponding sample. Determined by quantity. Topographical information is provided by the image and shows the surface embossment pattern of the sample in the FOV.

29. Measurement of topography information and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. Crystal information from the sample is measured as described in Example 20. Topographic information from the sample is measured as described in Example 28.

30. Measurement of topography information and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. Crystal information from the sample is measured as described in Example 31. Topographic information from the sample is measured as described in Example 28.

31. Measurement of topography information and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. Crystal information from the sample is measured as described in Example 19.

To measure topographic information from a sample, two or more detectors configured to measure He ions are located to detect He ions scattered from the sample surface at a large scattering angle. .. The He ion beam is rasterly scanned over the entire FOV region of the sample surface in a discontinuous step, and the total abundance of He ions according to the position of the He ion beam on the sample surface is measured by each detector. Using that total abundance value, a grayscale image of the sample corresponding to each detector is constructed, where the gray level at a particular image pixel is scattered at the He ion beam position on the corresponding sample. Determined by the total measured abundance of He ions. Next, the information from a plurality of images measured by the detector can be used in combination to determine quantitative three-dimensional topography information about the sample surface.

32. Measurement of topography information and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. Crystal information from the sample is measured as described in Example 20. Topographic information from the sample is measured as described in Example 31.

33. Measurement of topography information and crystal information from samples In order to measure topography information and crystal information from the sample, the sample is fixed at an appropriate position on the sample mounting part in a gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. Crystal information from the sample is measured as described in Example 21. Topographic information from the sample is measured as described in Example 31.

34. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19 .

To measure material information from a sample, a detector configured to measure He ions is located to detect backscattered He ions from the sample. The He ion beam is raster-scanned over the entire FOV region of the sample surface in a discontinuous step, and the total abundance of backscattered He ions is measured according to the position of the He ion beam on the sample surface. A grayscale image of the sample was constructed using backscattered He ion total abundance measurements, where the gray level at a particular image pixel is the backscattered He ion at the He ion beam position on the corresponding sample. Determined by the total measured abundance of. Since the scattering cross section of He ions is roughly determined by the square of the atomic numbers of the scattered atoms, the intensity of the image can be used to quantitatively determine the composition of the sample.

To measure the topographic information from the sample, the total intensity of secondary electrons is measured according to the position of the He ion beam on the surface of the sample, as described in Example 19. Next, the measured substance information is used to remove the contribution to the total secondary electron intensity measurement resulting from the variation in composition in the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values, where the gray level at a particular image pixel is determined by the corrected total intensity value. Topographical information is provided by the image and shows the surface embossment pattern of the sample in the FOV.

35. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 34.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 22. Using the measured substance information, the contribution to the secondary electron intensity measurement caused by the variation in the composition in the sample is removed at each incident angle of the ion beam. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 22. Next, quantitative three-dimensional topography information about the sample surface can be determined by using a combination of information from two images measured at different He ion beam incident angles.

36. Measurement of topography information and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 34.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 25. The measured substance information is used to remove the contribution to secondary electron intensity measurement at each detector resulting from compositional variations in the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 25. Next, the information from the images measured by the plurality of detectors can be used in combination to determine the quantitative three-dimensional topography information about the sample surface.

37. Measurement of topography information and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 34. Topographic information from the sample is measured as described in Example 28.

38. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 34. Topographic information from the sample is measured as described in Example 31.

39. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19.

An energy angle-resolved detector configured to measure He ions is located to detect He from the sample in order to measure material information from the sample. The He ion beam is rasterly scanned over the entire FOV region of the sample surface in a discontinuous step, and the energy and angle of the scattered He ions are measured according to the position of the He ion beam on the sample surface. From the average angle and average energy of the scattered He ions, the mass of the scattered atoms can be determined, and the composition of the sample can be determined.

To measure the topographic information from the sample, the total intensity of secondary electrons is measured according to the position of the He ion beam on the surface of the sample, as described in Example 19. Next, the measured substance information is used to remove the contribution to the total secondary electron intensity measurement resulting from the variation in composition in the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values, where the gray level at a particular image pixel is determined by the corrected total intensity value. Topographical information is provided by the image and shows the surface embossment pattern of the sample in the FOV.

40. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 39.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 22. Using the measured substance information, the contribution to the secondary electron intensity measurement caused by the variation in the composition in the sample is removed at each incident angle of the ion beam. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 22. Next, quantitative three-dimensional topography information about the sample surface can be determined by using a combination of information from two images measured at different He ion beam incident angles.

41. Measurement of topography information and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 39.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 25. The measured substance information is used to remove the contribution to secondary electron intensity measurement at each detector resulting from compositional variations in the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 25. Next, the information from the images measured by the plurality of detectors can be used in combination to determine the quantitative three-dimensional topography information about the sample surface.

42. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 39. Topographic information from the sample is measured as described in Example 28.

43. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 39. Topographic information from the sample is measured as described in Example 31.

44. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19.

In order to measure the substance information, an X-ray detector can be used to detect the X-rays that escape from the sample in response to the incident He ion beam. The He ion beam is rasterly scanned over the entire FOV region of the sample surface in a discontinuous step, and the X-ray emission spectrum is measured according to the position of the He ion beam on the sample surface. In particular, since the specific emission line in the X-ray spectrum is a specific type of atom, the composition at each stage on the sample surface is determined based on the measured X-ray spectrum.

To measure the topographic information from the sample, the total intensity of secondary electrons is measured according to the position of the He ion beam on the surface of the sample, as described in Example 19. Next, the measured substance information is used to remove the contribution to the total secondary electron intensity measurement resulting from the variation in composition in the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values, where the gray level at a particular image pixel is determined by the corrected total intensity value. Topographical information is provided by the image and shows the surface embossment pattern of the sample in the FOV.

45. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 44.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 22. Using the measured substance information, the contribution to the secondary electron intensity measurement caused by the variation in the composition in the sample is removed at each incident angle of the ion beam. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 22. Next, quantitative three-dimensional topography information about the sample surface can be determined by using a combination of information from two images measured at different He ion beam incident angles.

46. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 44.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 25. The measured substance information is used to remove the contribution to secondary electron intensity measurement at each detector resulting from compositional variations in the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 25. Next, the information from the images measured by the plurality of detectors can be used in combination to determine the quantitative three-dimensional topography information about the sample surface.

47. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 44. Topographic information from the sample is measured as described in Example 28.

48. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 44. Topographic information from the sample is measured as described in Example 31.

49. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19.

In order to measure the substance information, a photon detector can be used to detect photons that escape from the sample according to the incident He ion beam. The He ion beam is rasterly scanned over the entire FOV region of the sample surface in a discontinuous step, and the photon emission spectrum is measured according to the position of the He ion beam on the sample surface. In particular, since the specific emission line in the spectrum is a specific type of atom, the composition at each stage on the sample surface is determined based on the measured spectrum.

To measure the topographic information from the sample, the total intensity of secondary electrons is measured according to the position of the He ion beam on the surface of the sample, as described in Example 19. Next, the measured substance information is used to remove the contribution to the total secondary electron intensity measurement resulting from the variation in composition in the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values, where the gray level at a particular image pixel is determined by the corrected total intensity value. Topographical information is provided by the image and shows the surface embossment pattern of the sample in the FOV.

50. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 49.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 22. Using the measured substance information, the contribution to the secondary electron intensity measurement caused by the variation in the composition in the sample is removed at each incident angle of the ion beam. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 22. Next, quantitative three-dimensional topography information about the sample surface can be determined by using a combination of information from two images measured at different He ion beam incident angles.

51. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 49.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 25. The measured substance information is used to remove the contribution to secondary electron intensity measurement at each detector resulting from compositional variations in the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 25. Next, the information from the images measured by the plurality of detectors can be used in combination to determine the quantitative three-dimensional topography information about the sample surface.

52. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 49. Topographic information from the sample is measured as described in Example 28.

53. Measurement of topography information and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 49. Topographic information from the sample is measured as described in Example 31.

54. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19.

In order to measure material information, an Auger electron detector can be used to detect Auger electrons that escape from the sample in response to an incident He ion beam. The He ion beam is rasterly scanned over the entire FOV region of the sample surface in a discontinuous step, and the Auger electron emission spectrum is measured according to the position of the He ion beam on the sample surface. In particular, since the specific emission line in the spectrum is a specific type of atom, the composition at each stage on the sample surface is determined based on the measured spectrum.

To measure the topographic information from the sample, the total intensity of secondary electrons is measured according to the position of the He ion beam on the surface of the sample, as described in Example 19. Next, the measured substance information is used to remove the contribution to the total secondary electron intensity measurement resulting from the variation in composition in the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values, where the gray level at a particular image pixel is determined by the corrected total intensity value. Topographical information is provided by the image and shows the surface embossment pattern of the sample in the FOV.

55. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 54.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 22. Using the measured substance information, the contribution to the secondary electron intensity measurement caused by the variation in the composition in the sample is removed at each incident angle of the ion beam. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 22. Next, quantitative three-dimensional topography information about the sample surface can be determined by using a combination of information from two images measured at different He ion beam incident angles.

56. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 54.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 25. The measured substance information is used to remove the contribution to secondary electron intensity measurement at each detector resulting from compositional variations in the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 25. Next, the information from the images measured by the plurality of detectors can be used in combination to determine the quantitative three-dimensional topography information about the sample surface.

57. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 54. Topographic information from the sample is measured as described in Example 28.

58. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 54. Topographic information from the sample is measured as described in Example 31.

59. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19.

To measure material information, a TOF detector can be used to detect secondary ions and / or secondary atoms that escape from the sample depending on the incident He ion beam. The He ion beam is rasterly scanned over the entire FOV region of the sample surface in a discontinuous step, and the flight time of secondary ions and / or secondary atoms from the sample 180 is determined according to the position of the He ion beam on the sample surface. Measure. Based on the measured flight time of the ion / atom and the known voltage of the accelerating electrode in the TOF device, the mass of the detected particles can be calculated, and the identity of the particles can be further determined.

To measure the topographic information from the sample, the total intensity of secondary electrons is measured according to the position of the He ion beam on the surface of the sample, as described in Example 19. Next, the measured substance information is used to remove the contribution to the total secondary electron intensity measurement resulting from the variation in composition in the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values, where the gray level at a particular image pixel is determined by the corrected total intensity value. Topographical information is provided by the image and shows the surface embossment pattern of the sample in the FOV.

60. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 59.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 22. Using the measured substance information, the contribution to the secondary electron intensity measurement caused by the variation in the composition in the sample is removed at each incident angle of the ion beam. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 22. Next, quantitative three-dimensional topography information about the sample surface can be determined by using a combination of information from two images measured at different He ion beam incident angles.

61. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 59.

To measure the topographic information from the sample, the total intensity of secondary electrons from the sample is measured as described in Example 25. The measured substance information is used to remove the contribution to secondary electron intensity measurement at each detector resulting from compositional variations in the sample. A grayscale image of the sample is constructed using the corrected total secondary electron intensity values as described in Example 25. Next, the information from the images measured by the plurality of detectors can be used in combination to determine the quantitative three-dimensional topography information about the sample surface.

62. Measurement of topography information and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 59. Topographic information from the sample is measured as described in Example 28.

63. Measurement of topography and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 59. Topographic information from the sample is measured as described in Example 31.

64. Measurement of crystal information and substance information from a sample In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 44. Crystal information can be measured from the sample as described in Example 19.

65. Measurement of crystal information and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 44. Crystal information can be measured from the sample as described in Example 20.

66. Measurement of crystal information and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 44. Crystal information can be measured from the sample as described in Example 21.

67. Measurement of crystal information and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 49. Crystal information can be measured from the sample as described in Example 19.

68. Measurement of crystal information and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 49. Crystal information can be measured from the sample as described in Example 20.

69. Measurement of crystal information and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 49. Crystal information can be measured from the sample as described in Example 21.

70. Measurement of crystal information and substance information from a sample In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 54. Crystal information can be measured from the sample as described in Example 19.

71. Measurement of crystal information and substance information from a sample In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 54. Crystal information can be measured from the sample as described in Example 20.

72. Measurement of crystal information and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 54. Crystal information can be measured from the sample as described in Example 21.

73. Measurement of crystal information and substance information from a sample In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 59. Crystal information can be measured from the sample as described in Example 19.

74. Measurement of crystal information and substance information from a sample In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 59. Crystal information can be measured from the sample as described in Example 20.

75. Measurement of crystal information and substance information from samples In order to measure the topographical information and the substance information from the sample, the sample is fixed at an appropriate position of the sample mounting part in the gas field ion microscope as described in the present application. The gas electric field ion microscope is configured as described in Example 19. The substance information can be measured from the sample as described in Example 59. Crystal information can be measured from the sample as described in Example 21.

Other embodiments belong to the claims.

<figref num="1">FIG. 1 is a conceptual diagram of an ion microscope system.</figref><figref num="2">FIG. 2 is a conceptual diagram of a gas electric field ion source.</figref><figref num="3">FIG. 3 is an enlarged side view of one embodiment of the tip apex.</figref><figref num="4">FIG. 4 is an enlarged side view of the tip of FIG.</figref><figref num="5">FIG. 5 is a conceptual diagram of a helium ion microscope system.</figref><figref num="6">FIG. 6 is an enlarged top view of one embodiment of the W (111) tip.</figref><figref num="7">FIG. 7 is an enlarged side view of the tip of W (111) in FIG.</figref><figref num="8">FIG. 8 is a side view of the tip showing the measurement of the cone angle.</figref><figref num="9">FIG. 9 is a side view of the tip showing the measurement of the radius of curvature.</figref><figref num="10">FIG. 10 is a flow chart showing one embodiment of the tip manufacturing method.</figref><figref num="11">FIG. 11A is a perspective view of one embodiment of the tip support assembly. FIG. 11B is a bottom view of the support assembly of FIG. 11A.</figref><figref num="12">FIG. 12 is a side view of one embodiment of a support assembly that includes a Bogel attachment that supports the tip.</figref><figref num="13">FIG. 13 is a conceptual diagram of an embodiment of a gas electric field ion source and an ion optical instrument.</figref><figref num="14">FIG. 14 is a conceptual diagram of one embodiment of an ion optical system.</figref><figref num="15">FIG. 15 is a top view of one embodiment of the plurality of aperture diaphragms.</figref><figref num="16">FIG. 16 is a top view of one embodiment of the plurality of aperture diaphragms.</figref><figref num="17">FIG. 17 is a cross-sectional view of one embodiment of the moving mechanism for the tip of a gas electric field ion microscope.</figref><figref num="18">FIG. 18 is a conceptual diagram of the Everhart-Thornley detector.</figref><figref num="19">FIG. 19 is a partial cross-sectional view of a gas electric field ion microscope system including a microchannel plate detector.</figref><figref num="20">20A and 20B are side views and top views of island-shaped gold particles supported by a carbon surface. FIG. 20C is a plot of the total amount of secondary electrons abundant in the mean measurement, depending on the position of the ion beam for the samples of FIGS. 20A and 20B.</figref><figref num="21">FIG. 21 is a partial conceptual diagram of a gas electric field ion microscope including a gas delivery system.</figref><figref num="22">FIG. 22 is a partial conceptual diagram of a gas electric field ion microscope including a flood gun.</figref><figref num="23">FIG. 23 is a conceptual diagram of the sample including the inner charge layer.</figref><figref num="24">FIG. 24 is a conceptual diagram of a collector electrode for reducing the surface charge on the sample.</figref><figref num="25">FIG. 25 is a conceptual diagram of a flood gun device for reducing surface charge on a sample.</figref><figref num="26">FIG. 26 is a conceptual diagram of a flood gun device including a conversion plate for reducing the surface charge on the sample.</figref><figref num="27">FIG. 27A is a schematic diagram of a sample having a positive charge layer arranged within the sample. FIG. 27B is a schematic diagram of a sample having a positive charge layer and a negative charge layer arranged in the sample.</figref><figref num="28">FIG. 28 is a conceptual diagram of one embodiment of the vibration split sample manipulator.</figref><figref num="29">FIG. 29 is a conceptual diagram of one embodiment of the vibration split sample manipulator.</figref><figref num="30">FIG. 30 is a conceptual diagram in one embodiment of the vibration split sample manipulator.</figref><figref num="31">FIG. 31 is a conceptual diagram of an electrostatic filtration system for separating ions and neutral atoms in a particle beam.</figref><figref num="32">FIG. 32 is a conceptual diagram of an electrostatic filtration system for separating neutral atoms, monovalent ions and divalent ions in a particle beam.</figref><figref num="33">FIG. 33 is a conceptual diagram of a filtration system containing a non-dispersive sequence of electric and magnetic fields for separating neutral atoms, monovalent and divalent ions in a particle beam.</figref><figref num="34">FIG. 34A is a conceptual diagram showing one embodiment of the helium ion scattering pattern from the surface. FIG. 34B is a conceptual diagram showing a plot of the relative abundance of scattered helium ions detected by the detector in FIG. 34A.</figref><figref num="35-1">FIG. 35A is a conceptual diagram showing an embodiment of a helium ion scattering pattern from a surface using different detectors to detect scattered helium ions. FIG. 35B is a plot of total scattered helium ion emissions for the system shown in FIG. 35A. FIG. 35C is a plot of the relative abundance of scattered helium ions detected by the detector of FIG. 35A.</figref><figref num="35-2">FIG. 35D is a conceptual diagram showing an embodiment of a helium ion scattering pattern from a surface using different detectors to detect scattered helium ions. FIG. 35E is a plot of total scattered helium ion emissions for the system shown in FIG. 35D. FIG. 35F is a plot of the relative abundance of scattered helium ions detected by the detector of FIG. 35D.</figref><figref num="35-3">FIG. 35G is a conceptual diagram showing an embodiment of a helium ion scattering pattern from a surface using different detectors to detect scattered helium ions. Figure 35H is a plot of total scattered helium ion emissions for the system shown in Figure 35G. FIG. 35I is a plot of the relative abundance of scattered helium ions detected by the detector of FIG. 35G.</figref><figref num="36">FIG. 36 is a conceptual diagram showing a part of a gas electric field ion microscope including an arrangement of detectors for measuring scattered ions from a sample.</figref><figref num="37">FIGS. 37A to 37D are scanning electron microscope images of the conductive tip.</figref><figref num="38">FIG. 38 is a digital representation of the surface of the conductive tip.</figref><figref num="39">FIG. 39 is a plot of the surface tilt shown in FIG. 38.</figref><figref num="40">FIG. 40 is an electric field ion microscope image of a conductive tip having a trimer as a terminal shelf at the top thereof.</figref><figref num="41">FIG. 41 is a scanning electric field ion microscope image of a conductive tip having a trimer as a terminal shelf at the top thereof.</figref><figref num="42">FIG. 42 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="43">FIG. 43 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="44">FIG. 44 is a scanning field ion microscope image of the conductive tip.</figref><figref num="45">FIG. 45 is an electric field ion microscope image of a conductive tip having a trimer as a terminal shelf at the top thereof.</figref><figref num="46">FIG. 46 is a scanning electron microscope image of the conductive tip.</figref><figref num="47">FIG. 47 is an electric field ion microscope image of the conductive tip.</figref><figref num="48">FIG. 48 is an electric field ion microscope image of the conductive tip.</figref><figref num="49">FIG. 49 is an electric field ion microscope image of the conductive tip.</figref><figref num="50">FIG. 50 is a scanning field ion microscope image of a conductive tip having a trimer as a terminal shelf at its top.</figref><figref num="51">FIG. 51 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="52">FIG. 52 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="53">FIG. 53 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="54">FIG. 54 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="55">FIG. 55 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="56">FIG. 56 is a schematic view of the tip support.</figref><figref num="57">FIG. 57 is a schematic view of the tip support.</figref><figref num="58">FIG. 58 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="59">FIG. 59A is an image of a sample taken with a helium ion microscope configured to detect secondary electrons. FIG. 59B is an image of a sample taken with a scanning electron microscope.</figref><figref num="60">FIG. 60 is a graph of secondary electron currents from a sample.</figref><figref num="61">FIG. 61A is an image of a sample taken with a helium ion microscope configured to detect secondary electrons. FIG. 61B is an image of a sample taken with a scanning electron microscope.</figref><figref num="62">FIG. 62 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="63">FIG. 63 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="64">FIG. 64 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="65">FIG. 65 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="66">FIG. 66 is an embodiment of a detector configuration configured to detect secondary electrons.</figref><figref num="67">FIG. 67A is a graph of secondary electron intensity at variable sample positions based on the image of FIG. 59A. FIG. 67B is a graph of secondary electron intensity at variable sample positions based on the image of FIG. 59B.</figref><figref num="68">FIG. 68 is an image of a sample taken with a helium ion microscope configured to detect helium ions and neutral helium atoms.</figref><figref num="69">FIGS. 69A-69C are images of a sample taken with a helium ion microscope configured to detect helium ions and neutral helium atoms.</figref><figref num="70">FIG. 70A is an image of a sample taken with a helium ion microscope configured to detect helium ions and neutral helium atoms. FIG. 70B is polar coordinates showing the angular intensities of helium ions and helium atoms emitted from the sample for the image of FIG. 70A.</figref><figref num="71">FIG. 71A is an image of a sample taken with a helium ion microscope configured to detect helium ions and neutral helium atoms. FIG. 71B is polar coordinates showing the angular intensities of helium ions and helium atoms emitted from the sample for the image of FIG. 71A.</figref><figref num="72">FIG. 72 is an image of a sample taken with a helium ion microscope configured to detect helium ions and neutral helium atoms.</figref><figref num="73">FIG. 73 is an image of a sample taken with a helium ion microscope configured to detect helium ions and neutral helium atoms.</figref><figref num="74">FIG. 74 is an image of a sample taken with a helium ion microscope configured to detect photons.</figref><figref num="75">FIG. 75 is an image of a sample taken with a helium ion microscope configured to detect secondary electrons.</figref><figref num="76">FIG. 76 is a partially enlarged view of the image of FIG. 75.</figref><figref num="77">FIG. 77 is a plot of image intensity according to pixel position for the line scan in the image of FIG. 76.</figref><figref num="78">FIG. 78 is a plot of the data shown in FIG. 77 after the numerical scaling and smoothing operations.</figref><figref num="79">FIG. 79 is an image of a sample taken with a helium ion microscope configured to detect helium ions and neutral helium atoms.</figref><figref num="80">FIG. 80 is a plot of image intensity according to pixel position for line scanning through a portion of the image of FIG. 79.</figref><figref num="81">FIG. 81 is an image of a sample taken with a scanning electron microscope.</figref><figref num="82">FIG. 82 is a plot of image intensity according to pixel position for line scanning through a portion of the image of FIG. 81.</figref>

Code description

100 Gas Electric Field Ion Microscope System 110 gas source 120 Gas electric field ion source 130 Ion optics 133 Entrance opening 140 sample manipulator 148 Ionized disc 150 front detector 152 Virtual source 160 backside detector 170 Electronic control system 180 samples 182 gas 186 Conductive tip 187 Tip top 188 Suppressor 190 Extractor 191 opening 192 Ion beam 194 particles 200 microscope system 202 First vacuum housing 204 Second vacuum housing 208 Tip Manipulator 216 First lens 219 Scan deflector 220 Axis Alignment Deflector 221 Scanning deflector 222 Alignment deflector 224 Aperture 226 Second lens 227 axis of rotation 228 Delivery tube 229 opening 230 flow regulator 232 Temperature controller 234 Aperture mounting part 236 vacuum pump 237 vacuum pump 502 Shaft 503 inlet 504 Hemisphere 508 foundation 510 shoulder 514 Translation 520 Support assembly 522 Support pillar 524 Support base 526 heating wire 528 precursor wire 550 support assembly 552 mounting arm 554 spacer 556 Support base 600 ET detector 601 Particle Selector 602 Convertible substance 604 Support 606 Photon detector 607 power supply 608 power supply 610 charged particles 612 photon 730 delivery tube 732 inlet 734 vacuum pump 736 Sending nozzle 840 Flood gun 842 electron beam 846 Charge layer 847 Secondary electron 852 Collection electrode 854 conductor 900 Friction Spider 902 Support disc 904 Sample stand 906 Guide needle 908 Activator 1510 Sample retention assembly 1511 body 1512 opening 1514 Sample stand 1516 surface disc 1518 arm 1520 Grip 1522 Adjustable connector 1524 opening 1600 spider