System and method for monitoring spatial light modulator (SLM) flare

Abstract

Systems and methods for monitoring flare associated with maskless lithography systems using a spatial imaging system address the presence of excessive flare in maskless lithography systems.

Description

[0001] Cross-references

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 337,682, filed on May 3, 2022, entitled “SYSTEMS AND METHODS FOR MONITORING SPATIAL LIGHT MODULATOR (SLM) FLARE,” the entirety of which is incorporated herein by reference for all purposes. Technical Field Background Art

[0003] Certain maskless lithography systems and methods utilize one or more light sources, a spatial light modulator (SLM), and projection optics to project spatially patterned light onto photoresist on a wafer. The spatial pattern imparted by the SLM determines the location at which the photoresist is exposed. In order to expose all photoresist on the wafer, the wafer is moved relative to the SLM and projection optics (e.g., using an actuator system that moves a platform on which the wafer is positioned). As the wafer moves, the spatial pattern imparted by the SLM is updated to expose the photoresist at the desired location on the wafer. However, the use of an SLM in maskless lithography may introduce additional flare into the maskless lithography system optics. Therefore, the present disclosure provides systems and methods for monitoring flare (as an example, SLM flare) in a maskless lithography system. Summary of the invention BRIEF DESCRIPTION OF THE DRAWINGS

[0004] In the following detailed description and accompanying drawings, various embodiments of the present invention are disclosed.

[0005] Figure 1A A schematic diagram illustrating an exemplary system for monitoring SLM flare in a maskless lithography system when the system is operating in a first position is shown.

[0006] Figure 1B A schematic diagram is shown depicting an exemplary system for monitoring SLM flare in a maskless lithography system when the system is operating in a second position.

[0007] Figure 2A A flow chart depicting a first exemplary method for monitoring SLM flare in a maskless lithography system is shown.

[0008] Figure 2B A flow chart depicting a second exemplary method for monitoring SLM flare in a maskless lithography system is shown.

[0009] Figure 3 is a block diagram of a computer system used, in some embodiments, to implement portions of the method for monitoring SLM flare in a maskless lithography system set forth in the present disclosure.

[0010] Figure 4A An example of a checkerboard SLM pattern or reference modulation pattern as set forth in this disclosure is shown.

[0011] Figure 4B Shown in the light passing through Figure 4A An example of the simulated irradiance profile obtained after the checkerboard pattern is shown.

[0012] Figure 4C Show Figure 4B Examples of simulated central intensity for the irradiance profile shown.

[0013] Figure 4D Show Figure 4C Examples of simulated contrast for the irradiance profiles shown. DETAILED DESCRIPTION

[0014] The present invention may be implemented in a variety of ways, including as a process; an apparatus; a system; a composition of matter; a computer program product embodied in the form of a computer-readable storage medium; and / or a processor, for example, the processor being configured to execute instructions stored on and / or provided by a memory coupled to the processor. In this specification, these implementations or any other form that the present invention may take may be referred to as techniques. In general, the order of the steps of the disclosed process may be changed within the scope of the present invention. Unless otherwise stated, a component described as being configured to perform a task (e.g., a processor or memory) may be implemented as a general component that is temporarily configured to perform a task at a given time, or as a specific component that is manufactured to perform the task. The term "processor" used in this disclosure refers to one or more devices, circuits, and / or processing cores that are configured to process data (e.g., computer program instructions).

[0015] The following provides a detailed description of one or more embodiments of the present invention, and drawings that illustrate the principles of the present invention. The present invention is described in conjunction with such embodiments, however, the present invention is not limited to any embodiment. The scope of the present invention is limited only by the scope of the claims, and the present invention includes many alternatives, modifications and equivalents. In order to provide a comprehensive understanding of the present invention, many specific details are stated in the following description. These details are provided for the purpose of example, and the present invention can be practiced according to the scope of the claims without some or all of these specific details. For the sake of clarity, technical materials known in the technical field related to the present invention are not described in detail to avoid unnecessary confusion of the present invention.

[0016] The term "or" used in the present disclosure should convey both a disjunctive and a conjunctive meaning. For example, the phrase "A or B" should be interpreted as including only component A, only component B, and a combination of component A and component B.

[0017] As used in this disclosure, the term "flare" refers to unwanted reflected or scattered light that reaches a wafer during a lithography process. Flare can be caused by anything that forces light to travel in a direction different from that predicted by ray tracing methods. In general, flare can degrade the quality of exposure in lithography by exposing nominally dark features on the wafer, which reduces contrast. Flare can be quantified as the proportion of the total light energy reaching the wafer that comes from unwanted reflections or scattering within the lithography system or within components of the lithography system.

[0018] Certain maskless lithography systems and methods utilize one or more light sources, a spatial light modulator (SLM), and projection optics to project spatially patterned light onto photoresist on a wafer. The spatial pattern imparted by the SLM determines the locations where the photoresist is exposed. To expose all of the photoresist on the wafer, the wafer is moved relative to the SLM and projection optics (e.g., using an actuator system that moves a stage on which the wafer is positioned). As the wafer moves, the spatial pattern imparted by the SLM is updated to expose the photoresist at desired locations on the wafer. However, the use of an SLM in maskless lithography may introduce additional flare into the optics of the maskless lithography system. For example, an SLM may operate in a piston mode by raising or lowering a micromirror. This raising and lowering process may apply a 0 degree phase or a 180 degree phase to each pixel in the SLM. However, small errors in the raising and lowering process may cause phase errors that appear as flare. Small gaps between micromirrors, holes in the center of a micromirror, and defects in the coating of a micromirror may also cause flare. In addition, the flare associated with an SLM may change over time as the SLM components age.

[0019] Therefore, the problem of excessive flare in a maskless lithography system is solved by a system and method that uses a spatial imaging system to monitor flare associated with a maskless lithography system. The system and method generally utilize a platform that is configured to support a SLM and a reference plate featuring a reference modulation pattern. The platform is movable between two positions so that the SLM or the reference plate can receive source light from a light source. When the platform is positioned so that the SLM can receive the source light, the SLM imparts the SLM modulation pattern to the source light and projects the spatially modulated light to a projection lens. The projection lens projects a first image corresponding to the spatially modulated light. The first image is received by the spatial imaging system. When the platform is positioned so that the reference plate can receive the source light, the reference plate imparts the reference modulation pattern to the source light and projects the reference modulated light to the projection lens. The projection lens projects a second image corresponding to the reference modulated light. The second image is received by the spatial imaging system. The spatially modulated light includes: a first flare pattern containing a contribution from the SLM; and the reference modulated light includes: a second flare pattern containing a contribution from the reference plate. Assuming that the reference plate is substantially free of defects, the flare associated with the SLM can be determined by subtracting the second flare pattern from the first flare pattern. The resulting flare can be used to modify one or more parameters associated with the SLM, such as exposure time or exposure intensity of the spatially modulated light on the photoresist.

[0020] The present disclosure provides a system for monitoring the flare of a spatial light modulator (SLM) in a maskless lithography system, the system comprising: a platform, configured to: support the SLM and a reference plate, the platform being movable between a first position and a second position, wherein, in the first position, the SLM receives source light, imparts an SLM pattern to the source light, and projects spatially modulated light based on the SLM pattern, the spatially modulated light comprising a first flare pattern associated with the SLM, and in the second position, the reference plate receives the source light, imparts a reference modulation pattern to the source light, and projects reference modulated light based on the reference modulation pattern, the reference modulated light comprising a second flare pattern associated with the reference plate; and a projection lens, configured to: receive the spatially modulated light and project the reference light when the platform is located at the first position. The system further comprises a device for projecting a first image corresponding to the spatially modulated light, and when the platform is at the second position, receiving the reference modulated light and projecting a second image corresponding to the reference modulated light; a spatial imaging system configured to: when the platform is at the first position, receive the first image and output a first signal imaged with the first image, and when the platform is at the second position, receive the second image and output a second signal imaged with the second image; and a controller operably coupled to the platform and the spatial imaging system, the controller being configured to: (a) instruct the platform to move to the first position, (b) receive the first signal, (c) instruct the platform to move to the second position, (d) receive the second signal, and (e) determine a third flare pattern associated with the SLM error based on a difference between the first signal and the second signal. In some embodiments, the system further comprises: a light source configured to project source light. In some embodiments, the controller is further operably coupled to the SLM, wherein the controller is further configured to change one or more parameters associated with the SLM in response to the third flare pattern. In some embodiments, the one or more parameters include one or more members selected from the group consisting of: exposure time of spatially modulated light on the photoresist, exposure intensity of spatially modulated light on the photoresist, and phase of one or more pixels associated with the SLM. In some embodiments, the reference modulation pattern includes a static modulation pattern. In some embodiments, the spatial imaging system includes at least one deep ultraviolet (DUV) camera. In some embodiments, the SLM pattern or the reference modulation pattern is selected from the group consisting of: a checkerboard pattern, a flat line pattern, a parallelogram pattern, a diamond pattern, and a pattern including at least one alignment mark. In some embodiments, the source light includes 0BKK light or BBSK light. In some embodiments, the controller includes: a processor; and a memory coupled to the processor, wherein the memory is configured to provide instructions to the processor, which instructions, when executed, cause the processor to perform (a) to (e). In some embodiments, the controller includes: a processor configured to perform (a) to (e); and a memory coupled to the processor and configured to provide instructions for performing (a) to (e) to the processor.

[0021] The present disclosure further provides a method for monitoring flare of a spatial light modulator (SLM) in a maskless lithography system, the method comprising: (a) projecting source light onto the SLM, thereby imparting an SLM pattern onto the source light and projecting spatially modulated light based on the SLM pattern, the spatially modulated light comprising a first flare pattern associated with the SLM; (b) using a projection lens to receive the spatially modulated light and projecting a first image corresponding to the spatially modulated light; (c) using a spatial imaging system to receive the first image and output a first signal imaged with the first image; (d) projecting the source light onto a reference plate, thereby imparting a reference modulation pattern onto the source light and projecting a reference modulated light based on the reference modulation pattern, the reference modulated light comprising a second flare pattern associated with the reference plate; (e) using a projection lens to receive the reference modulated light and projecting a second image corresponding to the reference modulated light; (f) using a spatial imaging system to receive the second image and output a second signal imaged with the second image; and (g) determining a third flare pattern associated with an SLM error based on a difference between the first signal and the second signal. In some embodiments, the method further comprises: projecting the source light using a light source. In some embodiments, the method further comprises: modifying one or more parameters associated with the SLM in response to the third flare pattern. In some embodiments, the one or more parameters include one or more members selected from the group consisting of: exposure time of the spatially modulated light on the photoresist, exposure intensity of the spatially modulated light on the photoresist, and phase of one or more pixels associated with the SLM. In some embodiments, the reference modulation pattern comprises a static modulation pattern. In some embodiments, the spatial imaging system comprises at least one deep ultraviolet (DUV) camera. In some embodiments, the SLM pattern or the reference modulation pattern is selected from the group consisting of: a checkerboard pattern, a flat line pattern, a parallelogram pattern, a diamond pattern, and a pattern comprising at least one alignment mark.

[0022] Figure 1AA schematic diagram of an exemplary system 100 for monitoring SLM flare in a maskless lithography system is shown when the system 100 is operating in a first position. In the example shown, the system 100 includes a light source 110. In some embodiments, the light source is configured to project source light 112. In some embodiments, the light source 110 includes at least one light emitting diode (LED). In some embodiments, the light source 110 includes at least one laser source. In some embodiments, the laser source includes at least one continuous wave laser source. In some embodiments, the laser source includes at least one pulsed laser. In some embodiments, the laser source includes at least one gas laser (typically an argon fluoride (ArF) excimer laser or a krypton fluoride (KrF) excimer laser). In some embodiments, the laser source includes at least one metal-vapor laser. In some embodiments, the laser source includes at least one solid-state laser. In some embodiments, the laser source includes at least one semiconductor laser or a diode laser. Although in Figure 1A The system 100 is shown as including the light source 110 , however, in some embodiments, the system 100 does not include the light source 110 .

[0023] In the example shown, the system 100 includes a platform 120. In some embodiments, the platform 120 is configured to support the SLM 130 and the reference plate 140. In some embodiments, when the platform 120 is in a first position, the SLM 130 receives the source light 112, imparts the SLM pattern 132 to the source light 112, and projects the spatially modulated light 134 based on the SLM pattern 132. In some embodiments, the SLM pattern 132 includes a checkerboard pattern, a flat line pattern, a parallelogram pattern, a diamond pattern, or a pattern including at least one alignment mark. In some embodiments, the spatially modulated light 134 includes a first flare pattern associated with the SLM 130. In the example shown, the SLM 130 includes a reflective SLM. However, in some embodiments, the SLM 130 includes a transmissive SLM.

[0024] In the example shown, for simplicity, the SLM 130 provides an SLM pattern 132 having a display resolution of 8×6. However, the SLM pattern 132 can have any display resolution. In some embodiments, the SLM 130 has a pixel pitch of at least about 0.1 microns (μm) or greater than 0.1 microns. In some embodiments, the SLM 130 has a pixel pitch of at most about 10 microns or less than 10 microns. In some embodiments, the SLM 130 has a pixel pitch between about 0.1 microns and about 10 microns. In addition, for illustration purposes, the inset shows the SLM pattern 132 rotated 90 degrees.

[0025] In the example shown, system 100 includes projection lens 150. In some embodiments, projection lens 150 is configured to receive spatially modulated light 134 and project a first image 152 corresponding to spatially modulated light 134 when platform 120 is in the first position.

[0026] In the example shown, the system 100 includes a spatial imaging system 160. In some embodiments, when the platform 120 is in the first position, the spatial imaging system 160 is configured to: receive the first image 152 and output a first signal 162 corresponding to the first image 152. In some embodiments, the spatial imaging system 160 includes at least one ultraviolet (UV) camera or at least one deep UV (DUV) camera. In some embodiments, the spatial imaging system 160 is substantially similar to or identical to any of the systems disclosed in U.S. Pat. Nos. 8,809,616, 7,573,052, and 7,791,718, each of which is incorporated by reference in its entirety into this disclosure for all purposes.

[0027] In the illustrated example, system 100 includes controller 170. In some embodiments, controller 170 is operably coupled to platform 120 and spatial imaging system 160. In some embodiments, controller 170 is configured to receive first signal 162 when platform 120 is in a first position.

[0028] Figure 1B A schematic diagram is shown depicting an exemplary system 100 for monitoring SLM flare in a maskless lithography system when the system 100 is operated in a second position.

[0029] As in Figure 1A In the embodiment, the system 100 generally includes: a light source 110 configured to project a source light 112, a platform 120 configured to support an SLM 130 and a reference plate 140, a projection lens 150, a spatial imaging system 160, and a controller 170.

[0030] In the example shown, when the platform 120 is in the second position, the reference plate 140 receives the source light 112, imparts the reference modulation pattern 142 to the source light 112, and projects the reference modulated light 144 based on the reference modulation pattern 142. In some embodiments, the reference modulation pattern 142 comprises: a checkerboard pattern, a flat line pattern, a parallelogram pattern, a diamond pattern, or a pattern including at least one alignment mark. In some embodiments, the reference modulated light 144 comprises a second flare pattern associated with the reference plate 140. In some embodiments, the reference modulation pattern 142 comprises a static modulation pattern. In some embodiments, the reference plate 140 comprises a series of transmissive regions and a series of absorptive regions. In some embodiments, the transmissive regions and the absorptive regions simulate the behavior of an ideal SLM.

[0031] In the example shown, for simplicity, the reference plate 140 is provided with a reference modulation pattern 142 having a display resolution of 8x6. However, the reference modulation pattern 142 can have any display resolution. For example, in some embodiments, the reference modulation pattern 142 has a display resolution that is the same as the display resolution of the SLM pattern 132. For example, in some embodiments, the display resolution of the reference modulation pattern is greater or less than the display resolution of the SLM pattern 132. In addition, for illustration purposes, the inset shows the reference modulation pattern 154 rotated 90 degrees.

[0032] In the illustrated example, when the platform 120 is in the first position, the projection lens 150 is configured to receive the reference modulated light 144 and project a second image 154 corresponding to the reference modulated light 144 .

[0033] In the illustrated example, when platform 120 is in the second position, spatial imaging system 160 is configured to receive second image 154 and output second signal 164 corresponding to second image 154 .

[0034] As in Figure 1A In the embodiment, the system 100 includes a controller 180. In some embodiments, the controller 180 is operably coupled to the platform 130 and the spatial imaging system 170. In some embodiments, when the platform 120 is in the second position, the controller 170 is configured to receive the second signal 164.

[0035] In some embodiments, the controller 170 is configured to sequentially control the platform 120 and the spatial imaging system 160. Therefore, in some embodiments, the controller 170 is configured to perform the following series of operations: (a) instructing the platform 120 to move to a first position, (b) receiving a first signal 162 from the spatial imaging system 160, (c) instructing the platform 120 to move to a second position, (d) receiving a second signal 164 from the spatial imaging system 160, and (e) determining a third flare pattern associated with an SLM error based on a difference between the first signal 162 and the second signal 164. In some embodiments, the series of operations is repeated one or more times during the operation of the maskless lithography system.

[0036] In some embodiments, the controller 170 is operably coupled to the SLM 130. In some embodiments, the controller 170 is configured to change one or more parameters associated with the SLM 130 in response to the third flare pattern. For example, in some embodiments, the controller 170 is configured to change the spatially modulated light 134 in the photoresist ( Figure 1A or Figure 1B (not shown), the exposure time of the spatially modulated light 134 on the photoresist, or the phase of one or more pixels associated with the SLM 134. In some embodiments, the controller 170 includes: Figure 3 The illustrated computer system 300, or any component thereof.

[0037] FIG. 2 shows a flow chart depicting an exemplary method 200 for monitoring SLM flare in a maskless lithography system. In the illustrated example, at operation 210, source light is projected onto the SLM. In some embodiments, the source light is projected onto the SLM, thereby imparting an SLM pattern onto the source light, and spatially modulated light is projected based on the SLM pattern. In some embodiments, the spatially modulated light includes a first flare pattern associated with the SLM. In some embodiments, the SLM includes: Figure 1A or Figure 1B In some embodiments, the SLM pattern includes: Figure 1A or Figure 1B In some embodiments, the spatially modulated light comprises: Figure 1A or Figure 1B In some embodiments, the first flare pattern includes: Figure 1A or Figure 1B Any first flare pattern elaborated.

[0038] At operation 220, the spatially modulated light is received using a projection lens. In some embodiments, the projection lens is used to project a first image corresponding to the spatially modulated light. In some embodiments, the projection lens includes: Figure 1A or Figure 1B In some embodiments, the first image includes: Figure 1A or Figure 1B Any first image described.

[0039] At operation 230, a spatial imaging system is used to receive a first image and output a first signal mapped to the first image. In some embodiments, the spatial imaging system includes: Figure 1A or Figure 1B In some embodiments, the first signal includes: Figure 1A or Figure 1B Any first signal stated.

[0040] At operation 240, the source light is projected onto a reference plate. In some embodiments, the source light is projected onto the reference plate, thereby imparting a reference modulation pattern onto the source light, and the reference modulated light is projected based on the reference modulation pattern. In some embodiments, the reference modulated light includes a second flare pattern associated with the reference plate. In some embodiments, the reference plate includes: Figure 1A or Figure 1B In some embodiments, the reference modulation pattern includes: Figure 1A or Figure 1B In some embodiments, the reference modulated light includes: Figure 1A or Figure 1B In some embodiments, the second flare pattern includes: Figure 1A or Figure 1B Any secondary flare pattern elaborated.

[0041] At operation 250, a reference modulated light is received using a projection lens. In some embodiments, a second image corresponding to the reference modulated light is projected using a projection lens. In some embodiments, the second image includes: Figure 1A or Figure 1B Any second image described.

[0042] At operation 260, a second image is received using a spatial imaging system and a second signal is outputted that is mapped to the second image. In some embodiments, the second signal includes: Figure 1A or Figure 1B Any secondary signal described.

[0043] At operation 270, a third flare pattern associated with the SLM error is determined based on the difference between the first signal and the second signal. In some embodiments, the third flare pattern includes: Figure 1A or Figure 1B Any third flare pattern elaborated.

[0044] In some embodiments, the method 200 further comprises: modifying one or more parameters associated with the SLM in response to the third flare pattern. In some embodiments, the one or more parameters include: exposure time of the spatially modulated light on the photoresist, exposure intensity of the spatially modulated light on the photoresist, or phase of one or more pixels associated with the SLM.

[0045] In some embodiments, using the present disclosure regarding Figure 1A or Figure 1B The system 100 described herein or the disclosure regarding Figure 3 Computer system 300 is illustrated to implement method 200 , or any one or more of operations 210 , 220 , 230 , 240 , 250 , 260 , and 270 .

[0046] In some embodiments, the system 100 or method 200 is used to measure the SLM flare at different locations on the entire surface or a portion of the surface of the SLM to obtain flare measurement values ​​as a function of position on the SLM. In some embodiments, the spatial imaging system described in the present disclosure uses a scanning imaging protocol to measure the SLM flare at different locations on the SLM.

[0047] In some embodiments, the uniformity of illumination provided by a light source or by a light source and a projection lens is measured using system 100 or method 200. In some embodiments, the uniformity of illumination can be measured by setting all pixels of the SLM to a uniform phase or height. In some embodiments, the measured uniformity of illumination can enable the SLM to compensate for non-uniformities in illumination.

[0048] In some embodiments, a calibration profile is provided to the SLM using system 100 or method 200. In some embodiments, a white light interferometer (e.g., a Milbeau interferometer, a Michelson interferometer, a Linnik interferometer, etc.) is used to measure the height error or phase error in the pixels of the SLM. In some embodiments, the measured height error or phase error enables the SLM to compensate for such non-ideal conditions. In some embodiments, the white light interferometer includes any interferometer disclosed in U.S. Patent Nos. 11,099,007, 10,267,625, and 10,302,419, each of which is incorporated by reference in its entirety into this disclosure for all purposes.

[0049] In some embodiments, the relative position between the white light interferometer and the SLM defect detection system is calibrated using the system 100 or the method 200. In some embodiments, the relative position is calibrated using a reference modulation pattern or an SLM modulation pattern including alignment marks. In some embodiments, the SLM defect detection system includes any inspection apparatus disclosed in Japanese Patent No. 6969163, which is incorporated herein by reference in its entirety for all purposes.

[0050] In some embodiments, the illumination uniformity of an SLM defect detection system is calibrated using system 100 or method 200. In some embodiments, illumination uniformity is calibrated using an SLM pattern 132 that exhibits a flat pattern (ie, a pattern when all mirrors of SLM 130 are in the same state).

[0051] In some embodiments, height measurements of an SLM defect detection system may be calibrated using system 100. In some embodiments, height measurements are calibrated using an SLM pattern 132 that exhibits a checkerboard pattern.

[0052] In some embodiments, blind position adjustment is provided for an illumination pattern using system 100 or method 200. In some embodiments, the blind position adjustment uses a parallelogram illumination pattern and a test pattern comprising a parallelogram pattern. In some embodiments, the blind position adjustment uses a test pattern comprising a checkerboard pattern.

[0053] In some embodiments, a measurement of the optical power or intensity of the projected light described in the present disclosure is provided using system 100 or method 200. In some embodiments, the measurement of the optical power or intensity is measured using a test pattern comprising a solid pattern. In some embodiments, the measurement of the optical power or intensity is used to monitor any changes in the SLM, such as degradation of the intrinsic reflectivity of the SLM (e.g., degradation due to changes in the surface or coating of the SLM). In some embodiments, changes in the SLM are detected by comparing the measurement of the optical power or intensity passing through the SLM with the measurement of the optical power or intensity passing through the test pattern.

[0054] Figure 3 2 is a block diagram of a computer system 300 that is used in some embodiments to implement a portion of a method for monitoring SLM flare in a maskless lithography system described in the present disclosure (such as operation 270 of method 200 described in the present disclosure with respect to FIG. 2 ). In some embodiments, the computer system can be utilized as a component in a system for monitoring SLM flare in a maskless lithography system described in the present disclosure (e.g., in the present disclosure with respect to FIG. 2 ). Figure 1A or Figure 1B Controller 170 of the illustrated system 100). Figure 3 An embodiment of a general purpose computer system is shown. Other computer system architectures and configurations may also be used to implement the processing of the present invention. The computer system 300, which is composed of the various subsystems described below, includes at least one microprocessor subsystem 301. In some embodiments, the microprocessor subsystem includes at least one central processing unit (CPU) or a graphics processing unit (GPU). The microprocessor subsystem may be implemented by a single chip processor or by multiple processors. In some embodiments, the microprocessor subsystem is a general purpose digital processor that controls the operation of the computer system 300. The microprocessor subsystem uses instructions retrieved from the memory 304 to control the reception and manipulation of input data, and the output and display of data on the output device.

[0055] The microprocessor subsystem 301 is bidirectionally coupled to a memory 304, which may include a first main storage area, typically a random access memory (RAM), and a second main storage area, typically a read-only memory (ROM). As is known in the art, the main storage may be used as a general storage area and temporary storage memory and may also be used to store input data and processed data. The main storage may also store programmed instructions and data in the form of data objects and text objects, in addition to other data and instructions for the process of operating the microprocessor subsystem. Also as is known in the art, the main storage typically includes basic operating instructions, program code, data, and objects used by the microprocessor subsystem to perform its functions. Depending on, for example, whether data access needs to be bidirectional or unidirectional, the main storage device 304 may include any suitable computer-readable storage medium described below. The microprocessor subsystem 301 may also directly and very quickly retrieve and store frequently needed data in a cache (not shown).

[0056] Removable mass storage device 305 provides additional data storage capacity for computer system 300 and is coupled to microprocessor subsystem 301 bidirectionally (read / write) or unidirectionally (read-only). Storage 305 may also include computer readable media such as magnetic tape, flash memory, signals embodied in carrier wave form, personal computer cards (PC-CARDs), portable mass storage devices, holographic storage devices, and other storage devices. Fixed mass storage 309 may also provide additional data storage capacity. The most common example of mass storage 309 is a hard disk drive. Mass storage 305 and mass storage 309 generally store additional programmed instructions, data, etc. that are not normally in use by the processing subsystem. It should be understood that if desired, the information retained in mass storage 305 and mass storage 309 can be merged into a portion of main storage 304 (e.g., RAM) in a standard manner as virtual memory.

[0057] In addition to providing access to the storage subsystem to the processing subsystem 301, the bus 306 may also be used to provide access to other subsystems and devices. In the illustrated embodiment, these may include a display monitor 308, a network interface 307, a keyboard 302, and a pointing device 303, as well as auxiliary input / output device interfaces, a sound card, speakers, and other subsystems as needed. The pointing device 303 may be a mouse, a stylus, a trackball, or a tablet, and is helpful for interacting with a graphical user interface.

[0058] The network interface 307 enables the processing subsystem 301 to be coupled to another computer, computer network or telecommunication network using a network connection as shown. Via the network interface 307, it is expected that the processing subsystem 301 can receive information (e.g., data objects or program instructions) from another network or can output information to another network during the implementation of the above method steps. Information often represented as a sequence of instructions to be executed on the processing subsystem can be received from another network and output to another network in the form of a computer data signal embodied in the form of a carrier wave. An adapter card or similar device implemented by the processing subsystem 301 and appropriate software can be used to connect the computer system 300 to an external network and transmit data according to a standard protocol. That is, the method embodiment of the present invention can be executed only on the processing subsystem 301, or can be implemented on a network (e.g., the Internet, an intranet network or a local area network) in conjunction with a remote processing subsystem that shares a portion of the processing. An additional large-capacity storage device (not shown) can also be connected to the processing subsystem 301 via the network interface 307.

[0059] Auxiliary input / output (I / O) device interfaces (not shown) may be used in conjunction with computer system 300. Auxiliary I / O device interfaces may include general and customized interfaces that enable processing subsystem 301 to send data and more generally receive data from other devices (e.g., microphones, touch-sensitive displays, transducer card readers, tape readers, voice or handwriting recognizers, biometrics readers, cameras, portable mass storage devices, and other computers).

[0060] In addition, embodiments of the present invention are more related to computer storage products with computer-readable media, wherein the computer-readable media contains program codes for performing various computer-implemented operations. Computer-readable media is any data storage device that can store data that can be subsequently read by a computer system. The media and program codes can be media and program codes specially designed and constructed for the purposes of the present invention, or can be types of media and program codes known to those with ordinary knowledge in the field of computer software. Examples of computer-readable media include, but are not limited to, all of the media mentioned above: magnetic media (such as hard disks, floppy disks, and tapes); optical media (such as Compact Disc Read-Only Memory (CD-ROM) disks); magneto-optical media (such as 'floptical disks); and specially configured hardware devices (such as application-specific integrated circuits (ASICs), programmable logic devices (PLDs), and ROM devices and RAM devices). The computer readable medium can also be distributed over a network of coupled computer systems as a data signal embodied in a carrier wave form, so that the computer readable code is stored and executed in a distributed manner. Examples of program code include machine code such as that produced by a compiler, or files containing high-level code that can be executed using an interpreter. Figure 3 The computer system shown in is only an example of a computer system suitable for the present invention. Other computer systems suitable for the present invention may include more or fewer subsystems. In addition, bus 306 is an example of any interconnect scheme for linking subsystems. Other computer architectures with different subsystem configurations may also be used.

[0061] Examples

[0062] Example i: Checkerboard pattern

[0063] Figure 4A An example of a checkerboard SLM pattern or reference modulation pattern as described in the present disclosure is shown. In the example shown, the checkerboard pattern utilizes a series of dark squares and a series of light squares. Each of the dark and light squares constitutes an area of ​​36 nanometers (nm) by 36 nanometers and is separated from the other squares by a gap of 4 nanometers. The dark and light squares are arranged in a checkerboard pattern covering an area of ​​3 micrometers by 3 micrometers. The test pattern is arranged on a substrate of 6 micrometers by 6 micrometers.

[0064] Figure 4B Shown in the light passing through Figure 4A Example of a simulated irradiance profile obtained following a checkerboard pattern as shown. Figure 4C Show Figure 4B Examples of simulated central intensity for the irradiance profile shown. Figure 4D Show Figure 4C Examples of simulated contrast for the irradiance profile shown. FIG. 4B to FIG. 4D As shown in , the reference plate alone produces a sharp irradiance profile with minimal losses. The reference plate combined with an SLM without errors produces a less sharp irradiance profile with increased losses. The reference plate with an SLM subjected to phase errors caused by 8 nm micromirror position errors produces an even less sharp irradiance profile with even greater losses.

[0065] Detailed description of embodiments

[0066] Embodiment 1. A system for monitoring flare of a spatial light modulator (SLM) in a maskless lithography system, comprising:

[0067] A platform is configured to support the spatial light modulator and the reference plate, and the platform can move between a first position and a second position, wherein:

[0068] In the first position, the spatial light modulator receives source light, imparts a spatial light modulator pattern onto the source light, and projects spatially modulated light based on the spatial light modulator pattern, the spatially modulated light comprising a first flare pattern associated with the spatial light modulator,

[0069] In the second position, the reference plate receives the source light, imparts a reference modulation pattern to the source light, and projects a reference modulated light based on the reference modulation pattern, the reference modulated light comprising a second flare pattern associated with the reference plate;

[0070] The projection lens is configured as follows:

[0071] When the platform is located at the first position, the spatially modulated light is received and a first image corresponding to the spatially modulated light is projected,

[0072] When the platform is located at the second position, receiving the reference modulated light and projecting a second image corresponding to the reference modulated light;

[0073] A spatial imaging system is configured to:

[0074] When the platform is located at the first position, receiving the first image and outputting a first signal mapped with the first image,

[0075] When the platform is located at the second position, receiving the second image and outputting a second signal mapped with the second image; and

[0076] a controller operably coupled to the platform and the spatial imaging system, the controller being configured to:

[0077] (a) instructing the platform to move to the first position,

[0078] (b) receiving the first signal,

[0079] (c) instructing the platform to move to the second position,

[0080] (d) receiving the second signal, and

[0081] (e) determining a third flare pattern associated with a spatial light modulator error based on a difference between the first signal and the second signal.

[0082] Embodiment 2. The system according to embodiment 1 further comprises:

[0083] light source,

[0084] The light source is configured to project the source light.

[0085] Embodiment 3. A system according to embodiment 1 or 2, wherein:

[0086] The controller is further operably coupled to the spatial light modulator,

[0087] The controller is further configured to change one or more parameters associated with the spatial light modulator in response to the third flare pattern.

[0088] Embodiment 4. A system according to embodiment 3, wherein:

[0089] The one or more parameters include one or more members selected from the group consisting of:

[0090] The invention relates to an exposure time of the spatially modulated light on the photoresist, an exposure intensity of the spatially modulated light on the photoresist, and a phase of one or more pixels associated with the spatial light modulator.

[0091] Embodiment 5. A system according to any one of embodiments 1 to 4, wherein:

[0092] The reference modulation pattern comprises a static modulation pattern.

[0093] Embodiment 6. A system according to any one of embodiments 1 to 5, wherein:

[0094] The aerial imaging system includes at least one deep ultraviolet (DUV) camera.

[0095] Embodiment 7. A system according to any one of embodiments 1 to 6, wherein:

[0096] The spatial light modulator pattern or the reference modulation pattern is selected from the group consisting of:

[0097] A checkerboard pattern, a flat line pattern, a parallelogram pattern, a diamond pattern, and a pattern including at least one alignment mark.

[0098] Embodiment 8. A system according to any one of embodiments 1 to 7, wherein:

[0099] The source light includes OBKK light or BBSK light.

[0100] Embodiment 9. A system according to any one of embodiments 1 to 8, wherein:

[0101] The controller comprises:

[0102] Processor; and

[0103] a memory coupled to the processor,

[0104] The memory is configured to provide instructions to the processor, and when the instructions are executed, the processor performs (a) to (e).

[0105] Embodiment 10. A system according to any one of embodiments 1 to 8, wherein:

[0106] The controller comprises:

[0107] a processor configured to perform (a) to (e); and

[0108] A memory is coupled to the processor and configured to provide instructions for performing (a) to (e) to the processor.

[0109] Embodiment 11. A method for monitoring flare of a spatial light modulator (SLM) in a maskless lithography system, comprising:

[0110] (a) projecting source light onto a spatial light modulator, thereby imparting a spatial light modulator pattern onto the source light and projecting spatially modulated light based on the spatial light modulator pattern,

[0111] The spatially modulated light includes a first flare pattern associated with the spatial light modulator;

[0112] (b) using a projection lens to receive the spatially modulated light and project a first image corresponding to the spatially modulated light;

[0113] (c) using a spatial imaging system to receive the first image and output a first signal mapped to the first image;

[0114] (d) projecting the source light onto a reference plate, thereby imparting a reference modulation pattern onto the source light and projecting a reference modulated light based on the reference modulation pattern, the reference modulated light comprising a second flare pattern associated with the reference plate;

[0115] (e) using the projection lens to receive the reference modulated light and project a second image corresponding to the reference modulated light;

[0116] (f) using the spatial imaging system to receive the second image and output a second signal mapped to the second image; and

[0117] (g) determining a third flare pattern associated with a spatial light modulator error based on a difference between the first signal and the second signal.

[0118] Embodiment 12. The method according to embodiment 11 further includes:

[0119] The source light is projected using a light source.

[0120] Embodiment 13. The method according to embodiment 11 or 12, further comprising:

[0121] One or more parameters associated with the spatial light modulator are altered in response to the third flare pattern.

[0122] Embodiment 14. The method according to embodiment 13, wherein:

[0123] The one or more parameters include one or more members selected from the group consisting of:

[0124] The invention relates to an exposure time of the spatially modulated light on the photoresist, an exposure intensity of the spatially modulated light on the photoresist, and a phase of one or more pixels associated with the spatial light modulator.

[0125] Embodiment 15. The method according to any one of embodiments 11 to 14, wherein:

[0126] The reference modulation pattern comprises a static modulation pattern.

[0127] Embodiment 16. The method according to any one of embodiments 11 to 15, wherein:

[0128] The aerial imaging system includes at least one deep ultraviolet (DUV) camera.

[0129] Embodiment 17. The method according to any one of embodiments 11 to 16, wherein

[0130] The spatial light modulator pattern or the reference modulation pattern is selected from the group consisting of:

[0131] A checkerboard pattern, a flat line pattern, a parallelogram pattern, a diamond pattern, and a pattern including at least one alignment mark.

[0132] Embodiment 18. An exposure device comprising:

[0133] An illumination optical system configured to: illuminate a spatial light modulator having a plurality of spatial light modulation components, the plurality of spatial light modulation components having a reflective surface arranged on a setting plane;

[0134] a projection optical system configured to: project light from the spatial light modulator to a workpiece;

[0135] a reference member having a reference reflection pattern;

[0136] a position changing device configured to: change the positional relationship between the spatial light modulator, the reference member and the projection optical system into a first positional relationship in which the light from the illumination optical system enters the projection optical system via the spatial light modulator or a second positional relationship in which the light from the illumination optical system enters the projection optical system via the reference member; and

[0137] The detection device is configured to detect the light coming from the spatial light modulator or the reference member and passing through the projection optical system.

[0138] Embodiment 19. The exposure device according to embodiment 18 further comprises:

[0139] A computing device is configured to compute a state of the spatial light modulator based on a first output from the detection device in the first positional relationship and a second output from the detection device in the second positional relationship.

[0140] Embodiment 20. The exposure device according to embodiment 19, wherein:

[0141] The state of the spatial light modulator includes flare from the spatial light modulator.

[0142] Embodiment 21. The exposure device according to any one of Embodiments 18 to 20, wherein:

[0143] The detection device is configured to detect the aerial image of the spatial light modulator formed by the projection optical system and the reference pattern of the reference member formed by the projection optical system.

[0144] Embodiment 22. The exposure device according to embodiment 21, wherein:

[0145] The detection device is configured to detect the aerial image of the spatial light modulator in the first positional relationship and to detect the aerial image of the reference reflection pattern in the second relationship.

[0146] Embodiment 23. The exposure device according to any one of Embodiments 18 to 22, further comprising:

[0147] A controller is configured to control the patterns of the plurality of spatial light modulation components and the position changing device.

[0148] Embodiment 24. The exposure apparatus according to embodiment 23, wherein the controller is configured to:

[0149] The patterns of the plurality of spatial light modulation components are set to be the same as the reference reflection pattern.

[0150] Embodiment 25. The exposure device according to any one of Embodiments 18 to 24, wherein:

[0151] The reference reflective pattern includes at least one of a checkerboard pattern, a flat line pattern, a parallelogram pattern, a diamond pattern, and a pattern including at least one alignment mark.

[0152] Embodiment 26. An exposure method comprising:

[0153] illuminating a spatial light modulator having a plurality of spatial light modulation components having a reflective surface disposed on a setting plane;

[0154] projecting light from the spatial light modulator onto a workpiece using a projection optical system;

[0155] Setting the positional relationship between the spatial light modulator and the projection optical system to a first positional relationship, in which light from the spatial light modulator enters the projection optical system;

[0156] outputting a first output by detecting light from the spatial light modulator and through the projection optical system in the first relationship;

[0157] Setting the positional relationship between a reference member having a reference reflection pattern and the projection optical system to a second positional relationship, in which light from the reference member enters the projection optical system;

[0158] A second output is outputted by detecting the light from the spatial light modulator and passing through the projection optical system in the second relationship.

[0159] Embodiment 27. The exposure method according to embodiment 26 further comprises:

[0160] A state of the spatial light modulator is obtained based on the first output and the second output.

[0161] Embodiment 28. A method for manufacturing a device, comprising:

[0162] forming a resist on a surface of a substrate;

[0163] The exposure pattern is exposed using the exposure method described in Example 26 or 27.

[0164] Incidentally, as long as the national laws of the designated country (or selected country) to which this international application applies permit, the above-disclosed contents of all publications (including internationally disclosed manuals) and US patents related to the exposure equipment cited in each of the above embodiments and in the modified examples are incorporated herein by reference.

Claims

1. A system for monitoring flare of a spatial light modulator (SLM) in a maskless lithography system, comprising: A platform is configured to support the spatial light modulator and the reference plate, and the platform can move between a first position and a second position, wherein: In the first position, the spatial light modulator receives source light, imparts a spatial light modulator pattern onto the source light, and projects spatially modulated light based on the spatial light modulator pattern, the spatially modulated light comprising a first flare pattern associated with the spatial light modulator, In the second position, the reference plate receives the source light, imparts a reference modulation pattern to the source light, and projects a reference modulated light based on the reference modulation pattern, the reference modulated light comprising a second flare pattern associated with the reference plate; The projection lens is configured as follows: When the platform is located at the first position, the spatially modulated light is received and a first image corresponding to the spatially modulated light is projected, When the platform is located at the second position, receiving the reference modulated light and projecting a second image corresponding to the reference modulated light; A spatial imaging system is configured to: When the platform is located at the first position, receiving the first image and outputting a first signal mapped with the first image, When the platform is located at the second position, receiving the second image and outputting a second signal mapped with the second image; and a controller operably coupled to the platform and the spatial imaging system, the controller being configured to: (a) instructing the platform to move to the first position, (b) receiving the first signal, (c) instructing the platform to move to the second position, (d) receiving the second signal, and (e) determining a third flare pattern associated with a spatial light modulator error based on a difference between the first signal and the second signal.

2. The system according to claim 1, further comprising: light source, The light source is configured to project the source light.

3. The system according to claim 1 or 2, wherein: The controller is further operably coupled to the spatial light modulator, The controller is further configured to change one or more parameters associated with the spatial light modulator in response to the third flare pattern.

4. The system according to claim 3, wherein: The one or more parameters include one or more members selected from the group consisting of: The invention relates to an exposure time of the spatially modulated light on the photoresist, an exposure intensity of the spatially modulated light on the photoresist, and a phase of one or more pixels associated with the spatial light modulator.

5. The system according to any one of claims 1 to 4, wherein: The reference modulation pattern comprises a static modulation pattern.

6. The system according to any one of claims 1 to 5, wherein: The aerial imaging system includes at least one deep ultraviolet (DUV) camera.

7. A system according to any one of claims 1 to 6, wherein: The spatial light modulator pattern or the reference modulation pattern is selected from the group consisting of: A checkerboard pattern, a flat line pattern, a parallelogram pattern, a diamond pattern, and a pattern including at least one alignment mark.

8. The system according to any one of claims 1 to 7, wherein: The source light includes OBKK light or BBSK light.

9. The system according to any one of claims 1 to 8, wherein: The controller comprises: Processor; and a memory coupled to the processor, The memory is configured to provide instructions to the processor, and when the instructions are executed, the processor performs (a) to (e).

10. The system according to any one of claims 1 to 8, wherein: The controller comprises: a processor configured to perform (a) to (e); and A memory is coupled to the processor and configured to provide instructions for performing (a) to (e) to the processor.

11. A method for monitoring flare of a spatial light modulator (SLM) in a maskless lithography system, comprising: (a) projecting source light onto a spatial light modulator, thereby imparting a spatial light modulator pattern onto the source light and projecting spatially modulated light based on the spatial light modulator pattern, The spatially modulated light includes a first flare pattern associated with the spatial light modulator; (b) using a projection lens to receive the spatially modulated light and project a first image corresponding to the spatially modulated light; (c) using a spatial imaging system to receive the first image and output a first signal mapped to the first image; (d) projecting the source light onto a reference plate, thereby imparting a reference modulation pattern onto the source light and projecting a reference modulated light based on the reference modulation pattern, the reference modulated light comprising a second flare pattern associated with the reference plate; (e) using the projection lens to receive the reference modulated light and project a second image corresponding to the reference modulated light; (f) using the spatial imaging system to receive the second image and output a second signal mapped to the second image; as well as (g) determining a third flare pattern associated with a spatial light modulator error based on a difference between the first signal and the second signal.

12. The method according to claim 11, further comprising: The source light is projected using a light source.

13. The method according to claim 11 or 12, further comprising: One or more parameters associated with the spatial light modulator are altered in response to the third flare pattern.

14. The method according to claim 13, wherein: The one or more parameters include one or more members selected from the group consisting of: The invention relates to an exposure time of the spatially modulated light on the photoresist, an exposure intensity of the spatially modulated light on the photoresist, and a phase of one or more pixels associated with the spatial light modulator.

15. The method according to any one of claims 11 to 14, wherein: The reference modulation pattern comprises a static modulation pattern.

16. The method according to any one of claims 11 to 15, wherein: The aerial imaging system includes at least one deep ultraviolet (DUV) camera.

17. The method according to any one of claims 11 to 16, wherein: The spatial light modulator pattern or the reference modulation pattern is selected from the group consisting of: A checkerboard pattern, a flat line pattern, a parallelogram pattern, a diamond pattern, and a pattern including at least one alignment mark.

18. An exposure device comprising: An illumination optical system configured to: illuminate a spatial light modulator having a plurality of spatial light modulation components, the plurality of spatial light modulation components having a reflective surface arranged on a setting plane; a projection optical system configured to: project light from the spatial light modulator to a workpiece; a reference member having a reference reflection pattern; a position changing device configured to: change the positional relationship between the spatial light modulator, the reference member and the projection optical system into a first positional relationship or a second positional relationship, in which the light from the illumination optical system enters the projection optical system via the spatial light modulator, and in which the light from the illumination optical system enters the projection optical system via the reference member; as well as The detection device is configured to detect the light coming from the spatial light modulator or the reference member and passing through the projection optical system.

19. The exposure apparatus according to claim 18, further comprising: A computing device is configured to compute a state of the spatial light modulator based on a first output from the detection device in the first positional relationship and a second output from the detection device in the second positional relationship.

20. The exposure apparatus according to claim 19, wherein The state of the spatial light modulator includes flare from the spatial light modulator.

21. The exposure apparatus according to any one of claims 18 to 20, wherein: The detection device is configured to detect the aerial image of the spatial light modulator formed by the projection optical system and the reference pattern of the reference member formed by the projection optical system.

22. The exposure apparatus according to claim 21, wherein The detection device is configured to detect the aerial image of the spatial light modulator in the first positional relationship and to detect the aerial image of the reference reflection pattern in the second relationship.

23. The exposure apparatus according to any one of claims 18 to 22, further comprising: The controller is configured to control the patterns of the plurality of spatial light modulation components and the position changing device.

24. The exposure apparatus according to claim 23, wherein: The controller is configured to: The patterns of the plurality of spatial light modulation components are set to be the same as the reference reflection pattern.

25. The exposure apparatus according to any one of claims 18 to 24, wherein: The reference reflective pattern includes at least one of a checkerboard pattern, a flat line pattern, a parallelogram pattern, a diamond pattern, and a pattern including at least one alignment mark.

26. An exposure method comprising: illuminating a spatial light modulator having a plurality of spatial light modulation components, the plurality of spatial light modulation components having a reflective surface disposed on a setting plane; projecting light from the spatial light modulator onto a workpiece using a projection optical system; Setting the positional relationship between the spatial light modulator and the projection optical system to a first positional relationship, in which light from the spatial light modulator enters the projection optical system; outputting a first output by detecting light from the spatial light modulator and through the projection optical system in the first relationship; Setting the positional relationship between a reference member having a reference reflection pattern and the projection optical system to a second positional relationship, in which light from the reference member enters the projection optical system; A second output is outputted by detecting the light from the spatial light modulator and passing through the projection optical system in the second relationship.

27. The exposure method according to claim 26, further comprising: A state of the spatial light modulator is obtained based on the first output and the second output.

28. A method for manufacturing a device, comprising: forming a resist on a surface of a substrate; Using the exposure method according to claim 26 or 27, an exposure pattern is exposed.

Images