Lithography apparatus and method for manufacturing device

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

A lithographic device is a machine that applies a desired pattern to a target portion of a substrate. Lithographic equipment can be used, for example, in the manufacture of integrated circuits (ICs), flat panel displays and other devices that require microstructures. Traditional lithographic devices use patterning means, also known as masks or reticles, to generate circuit patterns that correspond to individual layers of the IC (or other device), which patterns are used in radiation-sensitive materials (eg, other devices). It is imaged on a target portion (including, for example, one or more die portions) on a substrate (eg, a silicon wafer or glass plate) having a layer of resist). The patterning means may also include an array of individually controllable elements that generate the circuit pattern instead of the mask.

Usually, one substrate contains a network adjacent to a target portion to be sequentially exposed. Known lithographic devices include a stepper that illuminates each of the target areas by exposing the entire pattern to the target area in one go, and scans the pattern with a projected beam in a given direction (the "scanning" direction). In addition, there is a scanner in which each of the target portions is irradiated by synchronously scanning the substrate in parallel or non-parallel in this direction.

Maskless lithography uses a projection system with a lens array designed to receive and focus individual parts of a patterned beam on a substrate. It is known to project to the target part of. Therefore, each of the lenses in the array projects the individual radiation spots onto the substrate, and the array of plurality of lenses projects the radiation pattern onto the substrate as a whole. Such a system is commonly referred to as a microlens array or MLA system. In such a system, the patterned beam is typically on a lens array via a beam expander that includes a series of lens components and is designed to provide a substantially parallel emission beam. It is being projected.

Ideally, the beam patterning and beam projection components are such that the individual spots projected onto the target substrate by the individual lenses of the MLA are sharply focused on the individual elements of the multiple controllable elements. And, it must be aligned exactly to correspond (ie, to each other and to the target substrate), but in order to be aligned correctly, the MLA of the patterned beam The components must be aligned so that the projection above and the MLA overlap. The individual lenses of the MLA must receive and focus a portion of the beam corresponding to the individual elements of the multiple controllable elements.

It will be understood that the "corresponding individual element" is the element on which the intensity of that part of the beam depends primarily. In general, the intensity of the beam portion received by a particular lens of MLA also depends on the state of multiple elements adjacent to its "corresponding" element.

There is a problem in accurately aligning a large number of beam patterning and beam projection components, thereby providing the desired corresponding relationship between the projected radiation spot and the controllable element.

Another potential problem is that the projected beam delivered to the patterning instrument (ie, an array of controllable elements) may not be uniform (ie, uniform across its cross section). It may not have strength). In such a case, even if the patterning component and the projection component are set up in an accurate alignment, the radiation pattern projected on the substrate will have an undesired intensity modulation.

<p> Therefore, there is a need for lithographic systems and methods that allow an accurate correspondence between the projected radiation spot and the controllable element and / or the projected beam with uniform intensity.</p>

<p> According to an embodiment of the present invention, an illumination system for supplying a projected radiation beam, an array of individually controllable elements that function to pattern the cross section of the projected beam, and a patterned beam. A lithography apparatus is provided that includes a projection system for projecting the image onto a target plane and a substrate table for supporting the substrate so that the target surface of the substrate and the target plane substantially coincide with each other. The projection system comprises at least one component. This component (or component) comprises an array of lenses designed to receive a patterned beam, the array of lenses laying out individual parts of the patterned beam. The individual lenses of the lens are designed to receive and focus, and to project the corresponding radiation pattern onto the target plane. In this embodiment, the lithography system further detects the intensity distribution of the projected radiation pattern (ie, provides an indication of the intensity distribution of the projected radiation pattern) and provides an intensity signal representing the detected intensity distribution. At least one of the position and orientation of the sensor system and at least one of the array of elements, the components of the projection system and the lighting system to adjust the projected radiation pattern. A positioning system that can be controlled and an array of a plurality of elements are controlled to give a predetermined pattern to the projected beam, the intensity signal is received, and the positioning system is controlled according to the detected intensity distribution. It comprises a control system designed to provide a control signal for, thereby adjusting the radiation pattern.</p><p> Therefore, in this embodiment, the control system that controls the positioning system according to the detected intensity distribution is not all components of the beam feeding system, patterning system and projection system whose position and / or orientation is fixed, but these. The position and / or orientation of at least one of the components of is adjustable.</p><p> In one embodiment, the intensity distribution for a given particular pattern applied to the beam, detected in the target plane, depends on the alignment of the components of the beam feeding system, patterning system and projection system. Therefore, the lithographic apparatus has the ability to auto-correct at least one component misalignment or actually auto-set a deliberate component "misalignment" (eg, the entire projected beam supplied). To compensate for the strength non-uniformity of, or to compensate for the misalignment of other components).</p><p> In one embodiment, the positioning system is adapted to provide independent coordination for multiple beam feeding components, patterning components and projection system components.</p><p> In one embodiment, the positioning system can be controlled to adjust the position and / or orientation of an array of multiple lenses.</p><p> In one embodiment, the projection system comprises a first portion with at least one lens and a second portion with an array of multiple lenses. The first part is designed to project a patterned beam onto an array of lenses. In this embodiment, the positioning system can be controlled so that the position and / or orientation of the lens in the first portion is adjusted, but in other embodiments, the projection system is other than this lens array. It may not have a lens.</p><p> For example, a projection system can replace the lens system with a mirror structure for directing a patterned beam (ie, an image of a patterning device / programmable mask) to an array of multiple lenses. Alternatively, it is possible to irradiate the patterning device with a light source such as a laser that provides a highly parallel beam, and then directly irradiate the lens array with the patterning laser beam reflected by the patterning device. Is.</p><p> In one embodiment, the second portion includes a mask with an opaque portion designed to block a portion of the patterned beam. This opaque portion defines an array of windows. Each of the windows is aligned with the corresponding lens in an array of lenses and is transparent to the patterned beam. The mask can be attached to an array of multiple lenses and can take the form of a sheet or layer of blocking material provided, for example, on the surface of the MLA. By incorporating the mask, the intensity distribution of the radiation pattern projected onto the target plane becomes more sensitive to the proper alignment of the various components. In particular, the intensity distribution is sensitive to its sizing (ie, magnification) and orientation suitability when projecting a patterned beam onto an array of multiple lenses. Also, by using masks and lens arrays, more obvious patterns of misalignment can be observed in the detected intensity distribution.</p><p> In one embodiment, the positioning system comprises an actuator that can control the lenses in the first portion to translate longitudinally with respect to the patterned beam, thereby on an array of lenses. The projection magnification of the patterned beam is adjusted (that is, the position of the lens in the first part is adjusted).</p><p> In one embodiment, the first portion can include a beam expander. The beam expander comprises a series of lens components with a first lens and a second lens. In this embodiment, the positioning system comprises an actuator system capable of controlling at least one of the first lens and the second lens to translate longitudinally with respect to the patterned beam. , Thereby adjusting the projection magnification of the patterned beam on an array of multiple lenses.</p><p> In one embodiment, the positioning system comprises an actuator that can control an array of controllable elements to translate along at least one axis, thereby patterning on the array of lenses. The projected beam is translated with respect to the array of the plurality of lenses.</p><p> In addition or otherwise, the positioning system has an actuator that can control an array of controllable elements to rotate around one axis, thereby patterning on the array of lenses. An actuator capable of rotating the beam projection with respect to the array of lenses and / or controlling the array of controllable elements to tilt about at least one axis. It is also possible to have it in the positioning system, thereby adjusting the tilt of the array of multiple elements with respect to the projected beam.</p><p> In one embodiment, the positioning system can control an array of multiple lenses to translate in a direction perpendicular to the target plane (eg, for adjusting focus), an array of multiple lenses. Can be controlled to translate along at least one axis parallel to the target plane (eg, to translate an array of lenses to a patterned beam projected by, for example, the first part). The actuator can be controlled so that an array of multiple lenses rotates about an axis perpendicular to the target plane (eg, an array of multiple lenses is patterned as projected by the first part). An actuator (to rotate with respect to the beam) and / or an array of multiple lenses can be controlled to tilt around at least one axis (eg, patterned by a first portion). An actuator (for adjusting the tilt of an array of multiple lenses with respect to the beam) can be provided.</p><p> In one embodiment, the sensor system is a sensor adapted to detect radiant intensity, and a sensor scanning system capable of controlling the sensor to scan over the entire area of the target plane on which the radiant pattern is projected. Can be provided. In another embodiment, the sensor system comprises an array of sensors configured to detect the intensity distribution without the need for scanning.</p><p> In one embodiment, the control system is adapted to control the element so that a predetermined geometric pattern is applied to the projected beam so that the intensity distribution to be detected includes a moiré pattern. Further, the control system is adapted to control the positioning system according to the moire pattern. It is also possible to adapt the control system to recognize multiple moiré patterns and control the positioning system according to the recognized patterns, thereby adjusting the alignment of the patterned beam with respect to multiple lens arrays. is there. Each of the moire patterns represents a characteristic of misalignment between individual component pairs, and the control system uses at least one component pair corresponding to the recognized pattern to correct the misalignment. It is preferable that it is adjusted.</p><p> According to another embodiment of the present invention, a step of providing a projected radiation beam using a lighting system and an array of individually controllable elements are used to impart a predetermined pattern to the cross section of the projected beam. A device manufacturing method is provided that includes a step of projecting a patterned radiation beam onto a target plane using a projection system. The projection system comprises at least one component. This component (or component) comprises an array of lenses designed to receive a patterned beam, the array of lenses laying out individual parts of the patterned beam. The individual lenses of the lens are designed to receive and focus, and to project the corresponding radiation pattern onto the target plane. In addition, this method includes a step of detecting the intensity distribution of the radiation pattern projected on the target plane, and an array of multiple elements of the projection system according to the detected intensity distribution in order to adjust the projected radiation pattern. The step of adjusting at least one of the components and the position and orientation of at least one of the lighting systems (eg, with respect to the target plane) and the substrate are provided so that the target surface and the target plane of the substrate are substantially aligned. And a step of supporting and using an array of individually controllable elements to impart the desired pattern to the cross section of the projected beam, and a beam having the desired pattern as the substrate target. It includes a step of projecting onto a target area on the surface.</p><p> In one embodiment, the adjustment step may include adjusting the position and / or orientation of a plurality of lens arrays.</p><p> In one embodiment, the projection system comprises a first portion with at least one lens and a second portion with an array of multiple lenses. The first part is designed to project a patterned beam onto an array of lenses, and the adjustment step includes a step of adjusting the position and / or orientation of the lenses in the first part. ..</p><p> In one embodiment, the adjustment step is (1) a step of translating the lens of the first portion (which may include, for example, a beam expander) longitudinally with respect to the patterned beam. To adjust the projection magnification of the patterned beam on an array of multiple lenses, (2) to translate an array of controllable elements along at least one axis, thereby multiple The projection of the patterned beam on the array of lenses in the lens translates with respect to the array of the lenses, (3) the step of rotating the array of controllable elements around one axis. The step by which the projection of the patterned beam on the array of multiple lenses rotates relative to the array of lenses, (4) tilting the array of controllable elements around at least one axis. The step of adjusting the tilt of the array of multiple elements with respect to the projected beam, (5) the step of translating the array of multiple lenses in a direction perpendicular to the target plane, (6). The step of translating an array of lenses along at least one axis parallel to the target plane, thereby translating the array of lenses with respect to the patterned beam projected by the first portion. Steps to: (7) Rotate an array of lenses around an axis perpendicular to the target plane, thereby patterning the array of lenses projected by the first portion. A step of rotating with respect to a beam and / or (8) a step of tilting an array of lenses around at least one axis, thereby for a patterned beam projected by a first portion. One or more of the steps in which the tilt of the array of multiple lenses is adjusted can be included.</p><p> In one embodiment, the detection step can include a step of providing and arranging a sensor for detecting the radiation intensity and a step of scanning the entire area of the target plane on which the radiation pattern is projected with the sensor. Alternatively, the detection step can include a step of providing and arranging an array of a plurality of sensors for detecting the intensity distribution.</p><p> In one embodiment, the method further includes the step of recognizing the detected pattern of intensity distribution. The recognized pattern is an misalignment between an array of elements, a component of the projection system (eg, a lens in the first part and / or an array of lenses) and a pair of components selected from the lighting system. Represents the characteristics of. In this embodiment, the adjustment step includes adjusting at least a pair of selected pairs of positions and / or orientations to correct this misalignment.</p><p> In one embodiment, the predetermined pattern applied to the beam is a geometric pattern, which includes a step of detecting a moiré pattern in the projected radiation pattern. In that case, the adjustment step includes a step of adjusting at least one of the above-listed components according to the detected moire pattern.</p><p> In one embodiment, the method can further include a step of recognizing the detected moiré pattern from a plurality of moiré patterns, each representing a characteristic of misalignment between individual component pairs. The adjustment step includes adjusting at least one of the individual pairs corresponding to the detected moire pattern.</p><p> In one embodiment, the adjustment step includes aligning an array of controllable elements and an array of lenses.</p><p> In one embodiment, the adjustment step includes adjusting the position and / or orientation of at least one of the components listed above to compensate for the intensity non-uniformity of the entire projected beam. There is. Therefore, this adjustment includes the step of deliberately setting the misalignment between, for example, an array of controllable elements and an array of lenses, in order to compensate for the non-uniformity of the supplied beam. Can be done.</p><p> In one embodiment, further, a step of setting the position and orientation of an array of multiple elements, a component of the projection system and a lighting system, and a step of detecting the corresponding intensity distribution of the radiation pattern projected on the target plane. Multiple elements: a step of moving at least one of an array of elements, a component of the projection system, and a lighting system, and a step of detecting changes in the corresponding intensity distribution of the radiation pattern projected onto the target plane. The method includes the steps of using varying intensity distributions to determine the optimal position of at least one of the array, projection system components and lighting system.</p><p> Therefore, in this example, the optimal position is predicted by modeling the detected pattern change as a function of the motion of an element or component of a particular imaging system (or a function of the number of elements / components). It can be determined more accurately by interpolation.</p><p> Hereinafter, other examples, features and advantages of the present invention, and the structures and operations of various examples of the present invention will be described in detail with reference to the accompanying drawings.</p><p> The accompanying drawings incorporated herein and forming part of the present specification demonstrate the invention, show the principles of the invention in more detail with the following description, and those skilled in the art. It plays a role in enabling the construction and use of the present invention.</p><p> Hereinafter, the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, similar reference numbers represent identical or functionally similar components.</p>

Overview and technology Although used herein is referred to for use in lithography equipment, especially in the manufacture of integrated circuits (ICs), the lithography equipment described herein is derivational and detection for integrated optical systems, magnetic region memories. It should be understood that it has other applications such as manufacturing patterns, flat panel displays, 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. Those skilled in the art will understand what they can do. The substrate referred to herein is, for example, in a track (eg, a tool that usually applies a resist layer to the substrate and develops an exposed resist) or a measuring or inspection tool, before or after exposure. Can be processed. Where applicable, the disclosure herein can be applied to such substrate processing tools and other substrate processing tools. Also, since the substrate can be processed multiple times, for example to generate a multilayer IC, the term substrate as used herein already includes the plurality of processed layers. It may also refer to the board.

The term "misalignment" should be interpreted in its broad sense and includes any deviation of one component from the other with respect to its nominally ideal position, orientation or separation. ..

The term "moire pattern" is also used in its broad sense, in a projected radiation pattern produced by projecting a geometrically patterned beam through a geometric array of multiple lenses. All patterns are included.

As used herein, the term "individually controllable array of elements" can be used to pattern the cross section of an incident radiation beam, thereby making the desired portion of the substrate desired. It should be broadly interpreted as meaning any means by which a pattern can be generated. Within this context, the terms "optical bulb" and "spatial light modulator" (SLM) can also be used. Examples of such patterning devices will be considered below.

The programmable mirror array can include a matrix processable surface with a viscoelastic control layer and a reflective surface. The basic principle underlying such a device is, for example, that the treated area of the reflective surface reflects the incident light as diffracted light, while the untreated area reflects the incident light as non-diffracted light. By using an appropriate spatial filter, non-diffracted light can be filtered out of the reflected beam, leaving only the diffracted light to reach the substrate, thus depending on the treatment pattern of the matrix processable surface. The beam is patterned.

It will be appreciated that this filter can, as an alternative, filter out diffracted light and leave non-diffracted light to reach the substrate. It is also possible to use an array of multiple diffractive optical microelectromechanical systems (MEMS) devices in a corresponding manner. Each of the diffractive optical MEMS devices is provided with a plurality of reflective ribbons that can be deformed with respect to each other, and can form a diffraction grating that reflects incident light as diffracted light.

Other alternative embodiments may include a programmable mirror array using micromirrors arranged in a matrix. Each of these micromirrors can be individually tilted around one axis by applying an appropriate local electric field or by using piezoelectric driving means. In this case as well, the mirrors can be matrix-processed so that the direction in which the incident radiation beam is reflected differs between the processed mirror and the unprocessed mirror. Therefore, this method reflects the incident radiation beam according to the processing pattern of the matrix-processable mirror. The beam is patterned. The required matrix processing is performed using appropriate electronic means.

In any of the situations described above, an array of individually controllable elements can include one or more programmable mirror arrays. For more information on the mirror array referenced above, see, for example, U.S. Pat. Nos. 5,296,891 and 5,523,193, both of which are incorporated herein by reference in their entirety, and PCT Patent Application WO 98/38597. And WO 98/33096.

It is also possible to use a programmable LCD array. U.S. Pat. No. 5,229,872, which is incorporated herein by reference in its entirety, describes one example of such a structure.

When using feature pre-biasing, optical approximation correction features, phase variational techniques, and multiple exposure techniques, for example, patterns that are "displayed" on an array of individually controllable elements are layers of the substrate or It should be understood that the pattern may be substantially different from the pattern that is ultimately transferred onto the substrate. Similarly, the pattern finally generated on the substrate does not have to correspond to the pattern formed at any given moment on an array of individually controllable elements. This is a pattern on an array of individually controllable elements in which patterns that are finally formed on individual parts of the substrate are stacked for a given time period or given number of exposures. / Or the case of a structure in which the relative position of the substrate is changed.

Although used herein is referred to for use in lithographic equipment, especially in the manufacture of ICs, the lithographic equipment described herein is for, for example, DNA chips, MEMS, MOEMS, integrated optics, and magnetic region memory. It should be understood that it has other applications such as the manufacture of induction and detection patterns, flat panel displays, 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. Those skilled in the art will understand what they can do. The substrate referred to herein is treated, for example, in a track (usually a tool that coats the substrate with a resist layer and develops an exposed resist) or in a measuring or inspection tool before or after exposure. be able to. Where applicable, the disclosure herein can be applied to such substrate processing tools and other substrate processing tools. Also, since the substrate can be processed multiple times, for example to generate a multilayer IC, the term substrate as used herein already includes the plurality of processed layers. It may also refer to the board.

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.

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 systems and catadioptric optics. Any use of the term "lens" herein can be considered as a synonym for the more general term "projection system".

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".

A lithographic device is a type of device that may have two or more board tables (and / or multiple mask tables) in some cases, and for such "multi-stage" machines, additional tables. 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.

Further, the lithographic apparatus may be a type of apparatus in which the substrate is immersed in a liquid having a relatively large refractive index (for example, underwater), 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 lithographic apparatus, for example, 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.

Lithographic devices also provide fluid processing to allow interaction between the fluid and the illuminated portion of the substrate (eg, selectively adding chemicals to the substrate or selectively modifying the surface structure of the substrate). It can be equipped with a cell.

Lithography Projection Device FIG. 1 is a schematic view of the lithography projection device 100 according to an embodiment of the present invention. Device 100 comprises at least a radiation system 102, an array of individually controllable elements 104, an objective table 106 (eg, a substrate table) and a projection system (lens) 108.

A radiation system 102 can be used to supply a projected radiation (eg, UV radiation) beam 110, which in this particular embodiment further comprises a radiation source 112.

An array of individually controllable elements 104 (eg, a programmable mirror array) can be used to apply a pattern to the projected beam 110. Normally, the position of the array 104 of the plurality of individually controllable elements can be fixed with respect to the projection system 108, but in the alternative structure, the array 104 of the plurality of individually controllable elements is individually controlled. An array 104 of a plurality of possible elements can be connected to a positioning device (not shown) for accurate positioning with respect to the projection system 108. As shown in the figure, the individually controllable elements 104 are reflective elements (eg, having a reflective array of individually controllable elements).

The objective table 106 may include a substrate holder (not shown) for holding the substrate 114 (eg, a resist-coated silicon wafer or glass substrate), and the objective table 106 may project the substrate 114 into a projection system 108. Can be connected to a positioning device 116 for accurate positioning with respect to.

Projection system 108 (eg crystal and / or CaF₂Using a lens system, or a catadioptric system with a lens element made of such a material, or a mirror system), a patterned beam received from the beam splitter 118 is received from a target portion 120 (eg, a substrate 114) of the substrate 114. It can be projected onto one or more dies). The projection system 108 can project an image of an array 104 of a plurality of individually controllable elements onto the substrate 114. Alternatively, the projection system 108 can project an image of a secondary source in which the elements of an array 104 of individually controllable elements act as shutters. The projection system 108 can also form a secondary source and include a microlens array (MLA) for projecting microspots onto the substrate 114.

The source 112 (eg, an excimer laser) can generate a radiation beam 122. The beam 122 is fed directly to the lighting system (illuminator) 124 or via a regulating device 126, such as the beam expander 126. The illuminator 124 may include a conditioning device 128 for setting the external and / or internal radial extents (generally referred to as σ-external and σ-internal, respectively) of the intensity distribution of the beam 122. Also, the illuminator 124 typically includes various other components such as an integrator 130 and a capacitor 132. According to this method, the cross section of the projected beam 110 that collides with the array 104 of a plurality of individually controllable elements can have a desired uniform intensity distribution.

Note that with respect to FIG. 1, the source 112 can be placed within the housing of the lithography projector 100 (as is often the case when the source 112 is a mercury lamp, for example). In an alternative embodiment, the radiation source 112 can also be located away from the lithography projection apparatus 100. In that case, the radiated beam 122 will be directed to device 100 (eg, using a suitable induction mirror). This latter scenario is often seen when the source 112 is an excimer laser. It should be understood that the scope of the invention is intended for both of these scenarios.

The beam 110 is then guided using a beam splitter 118 and then blocked by an array 104 of multiple individually controllable elements. The beam 110 reflected by the array 104 of a plurality of individually controllable elements passes through a projection system 108 that focuses the beam 110 on the target portion 120 of the substrate 114.

The board table 106 can be precisely moved using the positioning device 116 (and any optional interference measuring device 134 on the base plate 136 that receives the interference beam 138 via the beam splitter 140). Different target portions 120 can be placed in the optical path of the beam 110. When used, the position of the array 104 of individually controllable elements with respect to the optical path of the beam 110, for example during scanning, using a positioning device for the array 104 of individually controllable elements. Can be corrected accurately. Normally, the movement of the objective table 106 is not clearly shown in FIG. 1, but is achieved using long stroke modules (coarse positioning) and short stroke modules (precision positioning). It is also possible to place an array 104 of multiple elements that can be individually controlled using a similar system. Alternatively or additionally, the projected beam 110 is movable, while the required relative movement is provided by having the objective table 106 and / or the array 104 of multiple individually controllable elements have a fixed position. It will be understood that it is also possible.

In the alternative configuration of this embodiment, the substrate table 106 can be fixed and the substrate 114 can be moved on the substrate table 106. In such cases, a large number of openings are provided in the top flat surface of the substrate table 106 through which gas is supplied, thereby providing a gas cushion capable of supporting the substrate 114. This is conventionally called an air bearing structure. The movement of the substrate 114 on the substrate table 106 is carried out using one or more actuators (not shown) capable of accurately positioning the substrate 114 with respect to the optical path of the beam 110. Alternatively, the substrate 114 can be moved on the substrate table 106 by selectively starting and stopping the passage of gas through the openings.

In the present specification, the lithography apparatus 100 according to the present invention is described as an apparatus for exposing a resist on a substrate, but the present invention is not limited to such use, and the lithography apparatus 100 is not limited to such use. It will be appreciated that the device 100 can be used to project a patterned projection beam 110 for use.

The device 100 shown in the figure can be used in four preferred modes. 1. Step mode: The entire pattern on the array 104 of individually controllable elements is projected onto target portion 120 with a single exposure (ie, a single "flash"). The substrate table 106 is then moved to different positions in the x and / or y directions, and the different target portions 120 are illuminated by the patterned projection beam 110. 2. Scan mode: Basically the same as step mode, except that a given target area 120 is not exposed with a single flash. Instead, a patterned projection beam 110 is used because an array 104 of individually controllable elements can be moved at a velocity v in a given direction (so-called "scanning direction", eg y direction). The array 104 of a plurality of individually controllable elements is scanned. At the same time, the board table 106 moves in the same direction or in the opposite direction at a velocity V = Mv. M is the magnification of the projection system 108. According to this method, a relatively large target portion 120 can be exposed without sacrificing resolution. 3. Pulse mode: An array 104 of individually controllable elements is basically kept stationary and the entire pattern is projected onto the target portion 120 of the substrate 114 using the pulse emission system 102. The substrate table 106 moves at a essentially constant speed so that the projected beam 110 can be used to scan the lines between both ends of the substrate 114. Between the pulses of the radiation system 102, the patterns on the array 104 of multiple elements that can be individually controlled as needed are updated, and the pulses require a continuous target portion 120 on the substrate 114. The timing is adjusted so that it is exposed at the position. Thus, the patterned projection beam 110 can scan between both ends of the substrate 114, thereby exposing the complete pattern to the elongated compartments of the substrate 114. This process is repeated until the entire substrate 114 is exposed line by line. 4. Continuous scanning mode: Basically the same as pulse mode, but with a substantially constant radiation system 102, a patterned projection beam 110 scans between both ends of the substrate 114, exposing the substrate 114. The difference is that the patterns on the array 104 of the plurality of individually controllable elements are then updated.

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

In the embodiment shown in FIG. 1, the array 104 of the plurality of individually controllable elements is a programmable mirror array. The programmable mirror array 104 comprises micromirrors arranged in a matrix, each of which can be individually tilted around one axis. The degree of tilt defines the condition of the individual mirrors. These micromirrors can be controlled by appropriate control signals from the controller if the elements are complete. Each of the flawless elements can be controlled so that their state is any one of a series of states, so that the intensity of the corresponding pixel in the projected emission pattern can be adjusted.

In one embodiment, the sequence of states has (a) the least contribution of the radiation reflected by the mirror to the intensity distribution of the corresponding pixel, and even zero, the black state, (b) the contribution of the reflected radiation. It includes the whitest state, which is the largest, and (c) multiple intermediate states in which the contribution of reflected radiation is between (a) and (b). These states are divided into regular settings used for regular beam patterning / printing and compensation settings used to compensate for the effects of defective elements. The canonical setting includes a first group of black states and multiple intermediate states. This first group can be described as multiple gray states and can be selected so that the contribution to the intensity of the corresponding pixel gradually increases from the smallest black value to a particular normal maximum. Compensation settings include the remaining second group of intermediate states and the whitest state. This second group of multiple intermediate states can be described as multiple white states, providing a greater contribution than the normal maximum, gradually increasing to the true maximum corresponding to the whitest state. Can be selected. This second group of multiple intermediate states is described as multiple white states, but it will be appreciated that this is merely to facilitate the distinction between regular and compensated exposure steps. Alternatively, it is possible to describe all of the states as a series of gray states between black and white, which can be selected to enable grayscale printing.

Second Illustrative Lithography Device Figure 2 shows a lithographic device according to an embodiment of the present invention. In this embodiment, the illumination system 1 is adapted to supply the projected radiation beam 2 directly to the patterning means 3. The patterning means 3 includes an array of a plurality of elements 31 and 32 that can be individually controlled. For clarity, only four elements 31, 32 are shown, but in reality there may be more than one million individually controllable elements 31, 32. In this embodiment, the elements 31 and 32 are mirrors, the tilt angle of which can be set by applying an appropriate control signal 94 from the control system 9.

It will be understood that it is also possible to use other forms of controllable elements 31, 32. For example, these controllable elements may be movable gratings, such as those found in diffraction grating light bulbs manufactured by Silicon Light Machines in Sunnyvale, California.

Referring to FIG. 2, in this embodiment, the two elements 31 are set in the nominal "white" position and the two elements 32 are set in the nominal "black" position. Array 3 imparts a pattern to the projected beam 2. The patterned beam 4 reflected by the array 3 is then projected onto the target plane P by a projection system with a first portion 5 and a second portion 6.

In this embodiment, the first portion 5 receives a patterned substantially parallel beam 4 from the array 3 and focuses the received beam 4 through the aperture 54 of the aperture diaphragm 53. It is a beam expander equipped with the first lens 51. The patterned beam 4 is then magnified by a second lens 52 (eg, a field lens) into a substantially parallel beam and delivered to a second portion 6.

In this embodiment, the second portion 6 is an array of a plurality of lenses 61 laterally deployed with respect to the direction of the beam, and a portion of a patterned beam 4 that illuminates between adjacent lenses. It comprises an opaque masking structure 62 designed to block, so each of a series of lenses 61 receives and focuses individual parts of the patterned beam 4 to target the corresponding radiation spot. It is formed on the plane P. In one embodiment, the portion of the patterned beam 4 incident on the individual lens should correspond to the individual elements of the controllable elements 31 and 32 of the array 3.

In the embodiment shown in FIG. 2, a lithography apparatus is present in the set-up configuration rather than an array of a plurality of lenses 61 that project a radiation pattern onto the surface of a target substrate (not shown). The target substrate is not located below the array of multiple lenses 61 at this time. Instead, a sensor system 7 is placed to measure the intensity distribution of the radiation pattern projected on the target plane P. In this embodiment, the sensor system 7 comprises a sensor 71 and a scanning system 72, and the scanning system 72 controls the sensor 71 to scan the entire region of the target plane P in the direction indicated by the arrow A7. Can be controlled using. The sensor system 7 provides the intensity signal 73 to the control system 9.

The control system 9 adjusts the position and / or orientation of any one of the beam supply system, the beam patterning system and the beam projection system based on the detected intensity distribution. The 96 is designed to provide multiple actuators 81, 83, 85, 86.

For example, the actuator 83 is coupled to array 3 so that array 3 translates along any one of three axes (labeled x, y, and z) that are perpendicular to each other. Also, the array 3 can be controlled to rotate around these three axes. The z-axis shown in the figure is approximately perpendicular to the target plane P, and the x-axis and y-axis are parallel to the target plane P. It will be understood that the rotation of the array 3 around the x-axis or the y-axis means the tilt of the array 3 with respect to the target plane P.

The actuator 86 is coupled to the second part 6 of the projection system and controls the lens array 61 to translate along three axes perpendicular to each other and to rotate around those axes. be able to.

Actuator 85 adjusts the components of beam expander 5.

Actuator 81 adjusts the position and orientation of the lighting system 1.

In the embodiment shown in FIG. 2, the illumination system 1, array 3, beam expander 5, and lens array 61 adjust their positions and orientations along and around all three axes. Although coupled to each actuator individually, it will be appreciated that in alternative embodiments, the number of actuators used can be reduced and adjustments can be made more limited. For example, the position of the lighting system 1 can be fixed with respect to the target plane P and the actuator 81 can be omitted. In another embodiment, the actuator 83 can be arranged to adjust only the rotation of the array 3. In one embodiment, a single actuator can be used to adjust the translation or rotation of a single component around a single axis. Therefore, it will be understood that the number of actuators used and the degree of adjustment they provide can be selected according to the particular requirements.

Returning to the embodiment shown in FIG. 2, in the actuator 85 coupled to the beam expander 5, the positions of the lenses 51 and 52 are in the beam direction (in the z direction in FIG. 2) as shown by arrows A1 and A2. It can be controlled to be individually adjusted along the corresponding direction), whereby the control system 9 can control the magnification of the patterned beam 4 and the projection of the patterned beam 4 onto an array of multiple lenses 61. You can adjust the size.

In one embodiment, the array 3 and the array of lenses 61 may be individually rotated around the z-axis and individually translated along the x-axis and y-axis by the corresponding actuators 83 and 86. it can. This is multiple, along with the adjustable magnification provided by the beam expander 5, so that each of the multiple lenses 61 receives a portion of the beam corresponding to the individual elements of the multiple controllable elements 31, 32. It enables the positioning of the patterned beam 4 projected onto the array of lenses 61 of the lens 61 and the array of a plurality of lenses 61.

Illustrative MLA FIG. 3 is a schematic plan view of a microlens array (MLA) according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view taken along line AA of the MLA shown in FIG. In this embodiment, the MLA comprises a body of transparent material having a flat top surface and a bottom surface shaped to define a plurality of lenses 61. The MLA also comprises a mask structure in the form of a layer 62 of opaque material attached to the flat top surface of the transparent body. An array of a plurality of circular windows 63 is formed in the opaque layer 62, and each of the windows 63 is centered on a corresponding one of the plurality of lens portions 61. Although the figure shows an array of nine windows 63, it should be understood that in practice MLA can be equipped with up to one million or more microlenses.

Illustrative Patterning of a Projected Beam FIG. 5 shows a predetermined pattern applied to a cross section of a projected beam according to an embodiment of the present invention. The black squares represent areas with relatively high light intensity, and the white lines between the black squares represent areas with relatively low light intensity. In the context of FIG. 2, FIG. 5 can be thought of as a map representing the state of the array 3 patterning the beam 2. In this case, the black square represents the element in the "white" state, and the white line simply represents the space between the elements 31 and 32. The pattern shown in FIG. 5 is a geometric pattern including a high-intensity region arranged in a rectangular array.

FIG. 6 shows another predetermined pattern applied to the cross section of the projected beam according to an embodiment of the present invention. The pattern shown in FIG. 6 can be used for alignment purposes. Again, the black squares represent areas with relatively high light intensity, and the white squares and white lines represent areas with relatively low light intensity. Also in this case, when viewed as a map of a plurality of controllable element states, the black squares represent the elements in the "white" state, and the white squares represent the elements in the "black" state.

Illustrative Misalignment Depiction Figure 7 is a schematic representation of the rotational misalignment (ie, error) between the MLA and the projection of the patterned beam on the MLA, according to an embodiment of the invention. FIG. 7 exaggerates the rotational error, that is, the rotational misalignment between the microlens array 6 and the projection 46 of the patterned beam 4 on the microlens array 6. MLA6 and beam projection 46 are viewed along the nominal z direction.

FIG. 8 is a schematic representation of the radiation pattern projected onto the target plane via a masked MLA when the projected beam is patterned according to FIG. 5 and the rotational misalignment shown in FIG. 7 is present. Is. FIG. 8 can also be regarded as a diagram of the patterned beam through the MLA mask.

FIG. 9 is a schematic representation of the radiation pattern projected onto the target plane via a masked MLA when the projected beam is patterned according to FIG. 6 and the rotational misalignment shown in FIG. 7 is present. Is.

In the examples shown in FIGS. 8 and 9, it will be understood that the rotational error results in an intensity distribution that includes a moiré pattern. This moiré pattern can be considered to be the result of projecting a geometrically patterned beam through a geometric array of multiple MLA mask windows. The moire patterns in each intensity distribution shown in FIGS. 8 and 9 have a characteristic appearance. The intensity of the microspot is modulated in both x and y directions. Moire patterns can be thought of as consisting of macro spots. Assuming that the MLA was used more extensively and the beam was patterned using an element array with correspondingly more elements, the corresponding moiré pattern would have a rotational misalignment error. If it is small enough, it will contain a single macro spot. However, as the rotational misalignment error increases, the moiré pattern develops more macro spots arranged in a regular rectangular array. Therefore, the moire patterns that can be observed in FIGS. 8 and 9 represent the characteristics of rotational misalignment between the MLA and the projection of the patterned beam onto the MLA, respectively.

In one embodiment, the control system 9 is adapted to recognize this characteristic pattern and to appropriately adjust the beam pattern and projection components in order to correct the rotational misalignment error. In the case of the embodiment shown in FIG. 2, this modification can be achieved by controlling actuator 83 and / or actuator 86 to rotate array 3 and / or array 6 of multiple lenses around the z-axis. it can. The control system 9 can monitor changes to the projected radiation pattern as it adjusts the orientation of the components. The control system 9 can achieve alignment by this feedback. When the macro spots in the intensity distribution disappear, the array 3 and the array 6 of the plurality of lenses are properly rotationally aligned with each other.

FIG. 10 is a schematic representation of the magnification error between the MLA and the projection of the patterned beam on the MLA according to an embodiment of the present invention. This magnification error occurs when the projected beam 46 of the patterned beam on the MLA is greater than the MLA6.

FIG. 11 is a schematic representation of the radiation pattern projected onto the target plane via a masked MLA when the projected beam is patterned according to FIG. 5 and the magnification error shown in FIG. 10 is present. is there.

FIG. 12 is a schematic representation of the radiation pattern projected onto the target plane via a masked MLA when the projected beam is patterned according to FIG. 6 and the magnification error shown in FIG. 10 is present. is there.

Figures 11 and 12 show the intensity distribution of the target plane caused by such errors in the beams patterned according to Figures 5 and 6, respectively. Again, the intensity distributions each include a moiré pattern. This moiré pattern can also be considered to include macro spots, which is characteristic of magnification error. In the case of the device shown in FIG. 2, the control system 9 recognizes this characteristic pattern and controls the actuator 85 to adjust the vertical position of at least one of the lenses 51 and 52, thereby a plurality of lenses. It is adapted to reduce the size of the patterned beam projected onto 61 arrays.

FIG. 13 is a schematic representation of the skew error between the MLA and the projection of the patterned beam on the MLA according to an embodiment of the present invention, in which the projection 46 of the patterned beam onto the MLA 6 is rectangular. Instead, the skew error, which is a parallelogram, is shown.

FIG. 14 is a schematic representation of the radiation pattern projected onto the target plane via a masked MLA when the projected beam is patterned according to FIG. 5 and the skew error shown in FIG. 13 is present. is there.

FIG. 15 is a schematic representation of the radiation pattern projected onto the target plane via a masked MLA when the projected beam is patterned according to FIG. 6 and the skew error shown in FIG. 13 is present. is there.

14 and 15 show the intensity distribution of the target plane that occurs when the beam patterned according to FIGS. 5 and 6, respectively, is projected through the MLA. In the case of this skew misalignment, the resulting moire pattern in the intensity distribution contains macro lines rather than macro spots. Therefore, this different form of moiré pattern is characteristic of different types of misalignment errors.

The control system 9 shown in FIG. 2 controls the actuator 83 so that the array 3 is properly tilted around at least one of the x-axis and the y-axis in response to the detection and recognition of the moire pattern shown in FIGS. 14 and 15. This allows the patterned beam projection 46 and MLA6 to be superimposed.

It will be understood that many misalignments of different types can exist at the same time. Therefore, the detected intensity distribution may include a moire pattern with some characteristic components. In one embodiment, the control system 9 can be configured to detect individual characteristic components and to appropriately adjust the position and / or orientation of the beam patterning system and projection system.

It will also be appreciated that it is possible to have the control system 9 control the array 3 so that a plurality of different predetermined patterns are applied to the beam 2. For example, but not limited to them, a plurality of arrays of a plurality of lines or a plurality of arrays of a plurality of concentric circles can be included in these predetermined patterns. It will be apparent to those skilled in the art after reading the above description that certain types of misalignment errors can be easily detected by properly selecting a predetermined pattern to be applied to the beam.

It should be appreciated that the sensor systems of the various embodiments of the present invention may include photodetectors that can be placed on the substrate table and supported on the substrate table. The photodetector can be configured to scan the entire area of the MLA and create a map of the intensity of the entire area. It should also be understood that it is also possible to measure the uniformity of the entire exposure field using an optical sensor. In certain embodiments, it may be desirable to deliberately introduce misalignment (ie, error) in order to correct the non-uniformity of the entire image field due to the illumination source. The sensor / detector can take various forms, for example, the sensor / detector may be a photosensitive device such as a CCD or CMOS chip.

Conclusion The various examples of the present invention have been described above, but it should be understood that the above description is merely an example and does not limit the present invention in any way. It will be apparent to those skilled in the art that various modal changes and minor changes can be made to the embodiments described above without departing from the spirit and scope of the invention. Therefore, the views and scope of the present invention are not limited to the exemplary embodiments described above, and shall be defined solely by each claim of the claims and their equivalents.

<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 figure which shows the lithography apparatus by one Example of this invention.</figref><figref num="3">FIG. 3 is a schematic plan view of a microlens array (MLA) according to an embodiment of the present invention.</figref><figref num="4">It is a schematic cross-sectional view along the line AA of MLA shown in FIG.</figref><figref num="5">It is a figure which shows the predetermined pattern applied to the cross section of the projection beam by one Example of this invention.</figref><figref num="6">It is a figure which shows another predetermined pattern applied to the cross section of the projection beam by one Example of this invention.</figref><figref num="7">FIG. 6 is a schematic showing rotational misalignment (ie, error) between MLA and projection of a patterned beam on MLA according to an embodiment of the invention.</figref><figref num="8">FIG. 5 is a schematic showing a radiation pattern projected onto a target plane via a masked MLA when the projected beam is patterned according to FIG. 5 and the rotational misalignment shown in FIG. 7 is present.</figref><figref num="9">FIG. 5 is a schematic showing a radiation pattern projected onto a target plane via a masked MLA when the projected beam is patterned according to FIG. 6 and the rotational misalignment shown in FIG. 7 is present.</figref><figref num="10">FIG. 6 is a schematic showing a magnification error between MLA and projection of a patterned beam on MLA according to an embodiment of the present invention.</figref><figref num="11">FIG. 5 is a schematic diagram showing a radiation pattern projected onto a target plane via a masked MLA when the projected beam is patterned according to FIG. 5 and there is a magnification error shown in FIG.</figref><figref num="12">FIG. 5 is a schematic diagram showing a radiation pattern projected onto a target plane via a masked MLA when the projected beam is patterned according to FIG. 6 and the magnification error shown in FIG. 10 is present.</figref><figref num="13">FIG. 6 is a schematic showing a skew error between MLA and projection of a patterned beam on MLA according to an embodiment of the present invention.</figref><figref num="14">FIG. 5 is a schematic diagram showing a radiation pattern projected onto a target plane via a masked MLA when the projected beam is patterned according to FIG. 5 and the skew error shown in FIG. 13 is present.</figref><figref num="15">FIG. 5 is a schematic diagram showing a radiation pattern projected onto a target plane via a masked MLA when the projected beam is patterned according to FIG. 6 and the skew error shown in FIG. 13 is present.</figref>

Code description

1 Illumination system 2, 110 Projected radiation beam (projected beam) 3 Patterning means (array) 4 Patterned beam 5 First part of the projection system (beam expander) 6 Second part of the projection system (microlens) Array) 7 Sensor System 9 Control System 31, 32 Controllable Elements 46 Patterned Beam Projection 51 First Lens 52 Second Lens 53 Aperture Aperture 54 Aperture Aperture Aperture 61 Lens (Lens Array) 62 Opaque Masking Structure (Layer of Opaque Material) 63 Window 71 Sensor 72 Scanning System 73 Intensity Signal 81, 83, 85, 86 Actuator 91, 93, 94, 95, 96, 97 Control Signal 100 Lithography Projector 102 Radiation System (Pulse Radiation System) ) 104 Individually Controllable Array of Multiple Elements (Individually Controllable Multiple Elements, Programmable Mirror Array) 106 Objective Table (Board Table) 108 Projection System 112 Radiation Source 114 Board 116 Positioning Device 118, 140 Beam Splitter 120 Board Target Part 122 Radiation Beam 124 Illuminator (Illuminator) 126 Beam Expander (Adjusting Device) 128 External and / or Internal of Beam Intensity Distribution Adjustment device for setting radial extension 130 Integrator 132 Capacitor 134 Interference measurement device 136 Base plate 138 Interference beam P Target plane