Lithographic device and manufacturing method of device

The present invention relates to a lithography device and a device manufacturing method.

A graphic device is a machine that applies a desired pattern to a target portion of a substrate. The lithography equipment can be used, for example, in the manufacture of integrated circuits (ICs). In that case, a patterning device such as a mask is used to generate a circuit pattern corresponding to each layer of the IC, which pattern is on a substrate (eg, a silicon wafer) with a layer of radiation sensitive material (resist). Is imaged on the target portion of the (for example, consisting of one or more die portions). Usually, one substrate contains a network adjacent to a target portion to be sequentially exposed. Known lithography equipment includes a so-called stepper in which each of the target areas is irradiated by exposing the entire pattern to the target area in a single operation, and the pattern is projected in a given direction (scanning direction). ), And each of the target portions is irradiated by synchronously scanning the substrate in parallel or non-parallel in this direction, that is, there is a so-called scanner.

In order to transmit radiation from the radiation source to the target portion on the wafer, the lithography equipment requires a controlled environment, such as a vacuum environment. For example, a lithography system using polar UV (EUV) radiation (such as 13 nm radiation) requires a controlled environment in which the specific steam and specific gas levels are below predetermined levels. Steams and gases absorb EUV radiation or, in combination with EUV radiation, promote contamination of the optical surface. For EUV lithography equipment, the voltage division of hydrocarbon (CxHy) is 10 in a controlled environment.^-9Less than Thor and also water (H₂O) partial pressure is 10^-7Must be less than Thor. Every time a graphic device is opened for maintenance, for example, a controlled environment must be (re) established, which requires a lot of time (a few hours), and in the meantime, in fact. Above, graphic equipment cannot be used.

Also, for graphic equipment using other types of radiation (eg, radiation of 157 nm or 193 nm), the requirements for a controlled environment are different from those for EUV type lithography equipment. However, we also need a controlled environment. In this case, the time required to (re) establish a controlled environment is short, but it still affects the effective operating time of the lithography equipment. For example, when using radiation near 157 nm, air and water vapor absorb the radiation at 157 nm. To enable the effective use of this radiation, a controlled environment with air and water vapor below a predetermined concentration level is required. In this environment, the beam path of the lithography equipment is changed to nitrogen (N).₂), Helium (He) or by purging with a purging gas such as a mixture of gases that is substantially transparent to the emission of a projected beam at 157 nm. For 193 nm systems, the presence of oxygen must be substantially eliminated, for example by purging the system with dry nitrogen gas, as radiation is absorbed by atmospheric oxygen.

<p> According to one aspect of the present invention, there is provided a lithography device and a device manufacturing method that can be used more effectively (for example, have a long operating time).</p>

<p> According to one aspect of the invention, a source designed to provide radiation to a lighting system that emits radiation in a first wavelength range and radiation in a second wavelength range that is different from the first wavelength range. Patterned, with a radiation source made to provide, a support made to support a patterned device made to give a pattern to the cross section of the radiation, and a board table made to hold the board. A lithography device is provided with a projection system designed to project the emitted radiation onto a target portion of the substrate.</p><p> As a basic function of the lithography equipment, the substrate is exposed using radiation in the first wavelength range. The second wavelength range of radiation is used while a controlled environment for using the first wavelength range of radiation is established. Also, radiation in the second wavelength range can be used to expose other substrates, or to perform rectification or other maintenance functions of the lithography equipment. The radiation source can provide radiation in both wavelength ranges simultaneously, or in separate time windows, thus increasing the effective operating time of the lithography equipment.</p><p> In one embodiment of the invention, the source comprises a source adapted to provide radiation in both the first and second wavelength ranges, and further emits radiation in the first or second wavelength range. It is equipped with a removable filter designed to provide. This embodiment allows the insertion of radiation of a second wavelength into the normal radiation path of the lithography equipment, if desired. The removable filter can be adapted to transmit radiation in either the first or second wavelength range. For example, while a controlled environment is being established, any particles still present in the atmosphere are used to absorb radiation in the first wavelength range (effectively deliver radiation in the second wavelength range). It can also filter out radiation in the second wavelength range while the lithography equipment is in operation (first wavelength range).</p><p> In an alternative embodiment, the sources are a first source element adapted to provide radiation in the first wavelength range and a second source element adapted to provide radiation in the second wavelength range. It has an element and a removable radiation director, such as a mirror, that directs radiation from a second source element to the lighting system. In the case of this embodiment, radiation in the second wavelength range can be added to the optical path of the lithography device.</p><p> The first wavelength range is the wavelength range used only in a controlled environment, and the second wavelength range is used, for example, when a controlled environment has not been established. The controlled environment will vary depending on the type of lithography equipment, as discussed above, for example the level of vacuum (eg 10).^-5Less than Thor and even 10^-7It may be related only to (less than Thor). The controlled environment can also limit the levels of other gases and vapors that cause contamination of the lithography equipment, such as hydrocarbons or steam.</p><p> In another alternative embodiment, the EUV region has a first wavelength range, eg 13 nm, but the UV region has a first wavelength range, eg 157 nm or 193 nm. Therefore, the present invention can be applied to both future and existing types of lithography equipment.</p><p> As discussed above, a second wavelength range can be used to set up the lithography equipment. This setup includes one or more of calibration (of the interferometer), certification (such as mirror map determination), performance testing and alignment. When applied to an EUV type lithography device that must generate a controlled environment that requires a long time, this embodiment allows the EUV lithography device to be used more effectively in time.</p><p> Alternatively, or in the same embodiment, the first wavelength range can be used to expose the substrate and the second wavelength range can be used to expose other substrates. You can also use an EUV lithography device for non-EUV exposure while pumping down a controlled (high vacuum) environment.</p><p> In other embodiments of the invention, the second wavelength range resides in the range between 150 nm and 350 nm. In this wavelength range, the reflection of the mirror of the EUV lithography device is greater than 2%, so radiation in the second wavelength range can be used for alignment or calibration.</p><p> According to another aspect of the invention, a step of providing a substrate, a step of providing radiation in a first wavelength range and a second wavelength range different from the first wavelength range, and a pattern of cross sections of radiation. A device manufacturing method is provided that includes a step of projecting patterned radiation onto a target portion of the substrate. Radiations in the first and second wavelength ranges can be provided simultaneously or in different time windows.</p><p> According to the device manufacturing method according to the present invention, the lithography device can be used more effectively as in the embodiment of the lithography device according to the present invention mentioned above.</p><p> Although used herein is referred to for use in lithography equipment, especially in the manufacture of ICs, the lithography equipment described herein refers to integrated optics, induction and detection patterns for magnetic region memory, It should be understood that it has other applications such as the manufacture of liquid crystal displays (LCDs), thin film magnetic heads, etc. In the context of such alternative applications, any use of the terms "wafer" or "die" herein may be considered synonymous with the more general terms "board" or "target portion", respectively. Please understand what you can do. The substrate referred to herein is processed, for example, in a track (usually a tool that coats the substrate with a resist layer and develops an exposed resist) or a metering tool or inspection tool before or after exposure. can do. Where applicable, the disclosure herein can be applied to such substrate processing tools and other substrate processing tools. Further, since the substrate can be processed a plurality of times to generate a multilayer IC, for example, the term substrate used in the present specification is a substrate that already includes a plurality of processed layers. It may also point to.</p><p> As used herein, the terms "radiation" and "beam" include ultraviolet (UV) radiation (eg, radiation with wavelengths of 365 nm, 248 nm, 193 nm, 157 nm or 126 nm), polar ultraviolet (EUV) radiation (eg, radiation). Radiation with a wavelength range of 5 to 20 nm), and all types of electromagnetic radiation, including particle beams such as ion beams or electron beams, are included.</p><p> As used herein, the term "patterning device" is broadly defined to mean a device that can be used to pattern a cross section of a beam, thereby generating a pattern on a target portion of a substrate. Please be interpreted as. Also note that the pattern applied to the beam does not necessarily correspond exactly to the desired pattern in the target portion of the substrate. Usually, the pattern applied to the beam corresponds to a device generated at the target portion, for example, a specific functional layer in an integrated circuit.</p><p> The patterning device may be transmissive or reflective. Examples of patterned devices include masks, programmable mirror arrays and programmable LCD panels. Masks are well known in lithography, and mask types such as binary, alternating phase and decay phase shift, and various hybrid mask types are known. An example of a programmable mirror array uses micromirrors arranged in a matrix. Each of the micromirrors can be individually tilted so that the incident radiating beam is reflected in different directions, so that the reflected beam is patterned by this method.</p><p> The support supports the patterned device, for example the weight of the patterned device. The support holds the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithography device and other conditions, such as whether the patterning device is held in a vacuum environment. Mechanical tightening techniques, vacuum tightening techniques or other tightening techniques, such as electrostatic tightening techniques under vacuum conditions, can be used for the support. The support can be, for example, a frame or table that can be fixed or moved as needed and, for example, can reliably position the patterning device with respect to the projection system. Is also good. Any use of the term "reticle" or "mask" herein can be considered as a synonym for the more general term "patterned device".</p><p> As used herein, the term "projection system" refers to refractive optics, catadioptric systems, suitable for other factors, such as the exposure optics used, or the use of immersion liquid or vacuum. It should be broadly interpreted as including various types of projection systems, including optical systems and catadioptric optical systems. Any use of the term "lens" herein can be considered as a synonym for the more general term "projection system".</p><p> Lighting systems also include various types of optical components, including refracting optics, catoptrics and catadioptric optics, for guiding, shaping or controlling projected radiation beams. Such components are also hereinafter collectively or individually referred to as "lenses".</p><p> A lithography device is a type of device that may have more than one board table (and / or multiple mask tables) in some cases, and in the case of such a "multi-stage" machine, an additional table. Can be used in parallel, or preliminary steps can be performed on one or more tables while using one or more other tables for exposure.</p><p> Further, the lithography device may be a type of device in which the substrate is immersed in a liquid having a relatively large refractive index, for example, water, thereby filling the space between the final element of the projection system and the substrate. It is also possible to fill other spaces within the lithography equipment, such as between the mask and the first element of the projection system. Immersion techniques are well known in the art for increasing the numerical aperture of projection systems.</p><p> Hereinafter, examples of the present invention will be described with reference to the accompanying schematic drawings, although they are merely examples. In the figure, the corresponding reference symbols represent the corresponding parts.</p>

FIG. 1 is a schematic view of a graphic apparatus LP according to an embodiment of the present invention. This lithography device is equipped with an illumination system (illuminator) IL designed to provide a radiation (eg, UV or EUV radiation) beam PB. The first support (eg, mask table) MT is designed to support the patterning device (eg, mask) MA and places the patterning device accurately relative to the projection system (lens) PL. It is connected to the positioning device PM. The board table (eg wafer table) WT is designed to hold the board (eg resist coated wafer) W and is a second positioning device PW that accurately positions the board relative to the projection system (lens) PL. It is connected.

The projection system (eg reflection projection lens) PL is adapted to image the pattern applied to the beam PB by the patterning device MA onto the target portion of the substrate W (eg containing one or more dies). ing.

As shown in the figure, this lithography device is a reflective device (eg, using a reflective mask or a programmable mirror array of the type referenced above). Alternatively, the lithography device may be a transmissive (eg, using a transmissive mask) type device.

Illuminator IL provides the emitted beam PB from the source SO. If the source is, for example, a plasma power release, the source and lithography equipment can be separate components. In such cases, the source is not considered to form part of the lithography equipment, and the radiated beam usually uses a radiated collector with, for example, a suitable focusing mirror and / or spectral purity filter. Then, it is handed over from the radiation source SO to the illuminator IL. In other cases, for example, when the radiation source is a mercury lamp, the radiation source is a component of the lithography device. The radiation source SO and the illuminator IL can be called a radiation system.

The illuminator IL can include an adjustment device adapted to adjust the angular intensity distribution of the beam PB. Generally, at least the outer and / or inner radial extents (commonly referred to as σ-outer and σ-inner, respectively) of the intensity distribution in the pupil plane of the illuminator are adjustable. The illuminator provides a tuned radiation beam with the desired uniform intensity distribution in its cross section.

The beam PB is incident on the mask MA held on the mask table MT. The beam PB reflected by the mask MA passes through the lens PL that focuses the beam on the target portion of the substrate W. The board table WT can be precisely moved using a second positioning device PW and position sensor IF2 (eg interfering device), which allows, for example, to place different target parts within the optical path of the beam PB. it can. Similarly, using the first positioning device PM and position sensor IF1, place the mask MA accurately with respect to the optical path of the beam PB, for example after a mechanical search from the mask library or during scanning. Can be done. Normally, the movement of the objective tables MT and WT is realized by using the long stroke module (coarse positioning) and the short stroke module (precision positioning) that form a part of the positioning devices PM and PW. For steppers (rather than scanners), the mask table MT can only be connected to or fixed to short stroke actuators. The mask MA and the substrate W can be aligned using the mask alignment marks M1 and M2 and the substrate alignment marks P1 and P2.

The device shown in the figure can be used in the preferred modes shown below. 1. Step mode Basically, the mask table MT and the substrate table WT are kept stationary, and the entire pattern applied to the projected beam is projected onto the target part at one time (that is, a single static exposure). The substrate table WT is then shifted in the X and / or Y directions to expose different target portions. In step mode, the maximum size of the exposure field limits the size of the target area imaged in a single static exposure. 2. Scanning mode The mask table MT and substrate table WT are synchronously scanned (ie, single dynamic exposure) while the pattern applied to the projected beam is projected onto the target area. The speed and direction of the substrate table WT with respect to the mask table MT are determined by the magnification (reduction ratio) and image inversion characteristics of the projection system PL. In scanning mode, the maximum size of the exposure field limits the width of the target area (in the non-scanning direction) in a single dynamic exposure, and the length of the scanning motion determines the height of the target area (in the scanning direction). Will be done. 3. Other modes The mask table MT is essentially kept stationary to hold the programmable patterning device, and the substrate table WT is moved or scanned while the pattern applied to the projected beam is projected onto the target portion. In this mode, a pulse source is typically used and the programmable patterning device is updated as needed during each scan, each time the substrate table WT moves, or between successive and continuous radiation pulses. .. This mode of operation can be easily applied to maskless lithography utilizing programmable patterning devices such as the type of programmable mirror array referenced above.

It is also possible to use the combination of usage modes described above and / or a variant thereof or a completely different usage mode.

Since many molecules in the normal atmosphere absorb radiation of 13 nm wavelength, the lithographic device described above, for example operating with EUV radiation, for exposing substrate W requires an ultra-high vacuum environment. is there. In order to reach the ultra-high vacuum environment, every space in the lithography equipment to which the exposure radiation propagates must be in the ultra-high vacuum environment. To that end, the main parts of the lithography equipment and its related components are placed in a vacuum chamber. The process of evacuating the vacuum chamber requires several hours, during which the lithography equipment cannot be used to properly expose the substrate.

FIG. 2 is a simplified diagram showing the first embodiment of the radiation source SO of the lithography apparatus shown in FIG. 1 in more detail. In this embodiment, the source SO comprises two source elements 2 and 3. The first source element 2 emits at the first primary wavelength used for the normal operation of the lithography equipment. This first source element 2 comprises, for example, an EUV source, providing 13 nm radiation, for example, to the lighting system IL.

The second source element 3 emits at a second wavelength that can be used in the lithography equipment until it reaches the ultra-high vacuum environment. This second wavelength is preferably in the range of 150 nm to 350 nm. The mirrors and optics used in the lithography equipment are designed for EUV emission (13 nm), but will also result in reflections of the second wavelength. Masks and optics designed for EUV radiation do not allow radiation of second wavelengths to pass through very well (estimated to be greater than 2%), but are still sufficient for most applications.

A movable mirror 4 is provided to allow radiation from the second source element 3 to reach the lithography equipment. During normal operation, the mirror 4 can be moved out of the beam path of the first source element 2 towards the lighting system IL. The movable mirror 4 can also be implemented using a tilted mirror structure in which the mirror 4 can be placed in the orientation shown in FIG. 2 while the lithography device is in the pump down phase. The mirror 4 can be tilted during the operating phase to allow the delivery of radiation from the first source element 2 to the lighting system IL.

FIG. 3 shows another embodiment of the source SO according to the present invention. In this embodiment, the source SO comprises a single source 1 that emits radiation at both the first and second wavelengths, eg, a filter 5 for passing only radiation of the second wavelength. , Provided between radiation source 1 and lighting system IL. A second filter (not shown) can be used to pass only radiation of the first wavelength, and depending on the position of the first filter 5 or second filter in the radiation beam path. You can choose between the first wavelength and the second wavelength. Alternatively, it is possible to use a filter 5 that allows only radiation of the first wavelength to pass through in the operating state of the lithography device. This filter 5 is removed during the vacuum phase because the molecules still present in the atmosphere absorb the radiation of the first wavelength.

A second wavelength of radiation can be used during the period during which the ultra-high vacuum is established in the lithography equipment. The emission of the second wavelength can be used for setup and certification of lithography equipment, performance tests such as mirror maps and calibration of interferometers. When the second wavelength emission is used in the setup process, a sensor that can operate at the second wavelength, for example known in other types of lithography equipment, can be used. Also, during the period of establishment of the vacuum, the radiation of the second wavelength can be used to expose other wafers (possibly using different types of masks). In either case, the operating time becomes long and the lithography device can be effectively used.

Any type of radiation source, including a discharge lamp, can be used as the radiation source described above with reference to various embodiments.

Although the embodiment of the present invention has been described with reference to an EUV lithography device having a first operating wavelength of around 13 nm, the multi-wavelength radiation source according to the present invention can also be applied to other types of lithography devices. Is. A high vacuum environment is also required for the lithography equipment that operates at the primary operating wavelength of about 157 nm or about 193 nm. Even in such a case, the lithography equipment is effective by using the radiation source of the second wavelength. The operating time can be lengthened.

Although the specific embodiment of the present invention has been described above, it will be understood that the present invention can be practiced by a method other than those described above. The above description is not intended to limit the present invention.

<figref num="1">It is a figure which shows the lithography apparatus by one Example of this invention.</figref><figref num="2">It is a simplified diagram which shows the 1st Example of the radiation source SO of the lithography apparatus shown in FIG. 1 in more detail.</figref><figref num="3">It is a simplified diagram which shows the 2nd Example of the radiation source SO of the lithography apparatus shown in FIG. 1 in more detail.</figref>

Code description

1 Single source 2, 3 Source element 4 Movable mirror 5 Filter IF1, IF2 Position sensor IL Illuminator IL Illuminator LP lithography device M1, M2 Mask alignment mark MA Patterning device (mask) MT 1st support (Mask table) P1, P2 board alignment mark PB radiation beam PL projection system (lens) PM 1st positioning device PW 2nd positioning device SO radiation source W board (resist coated wafer) WT board table