Image stabilization for digital lithography

Abstract

The present disclosure provides methods and systems for correcting a projection of an image from a spatial light modulator (SLM) to a substrate when there is cross-scan vibration including sub-pixel cross-scan vibration. These methods and systems include offsetting a mask pattern on an SLM that rotates relative to a lateral scan travel direction on a substrate, offsetting along an axis of the SLM to correct cross-scan vibrations, and delaying or accelerating projection of the mask pattern onto the substrate.

Description

[0001] This application is a divisional application of patent application No. 202080099720.1, filed on April 29, 2020, entitled "Image Stabilization for Digital Lithography". background Technical Field

[0002] Embodiments of this disclosure generally relate to lithography systems. In particular, embodiments of this disclosure relate to a method for image stabilization in digital lithography. Background Technology

[0003] Digital lithography is widely used in the manufacture of semiconductor devices, such as for back-end processing of semiconductor devices and display devices, including liquid crystal displays (LCDs) and light-emitting diode (LED) displays. For example, large-area substrates are frequently used in the manufacture of LCDs. LCDs, or flat panel displays, are often used in active-matrix displays, such as computers, touchpad devices, personal digital assistants (PDAs), cellular phones, television monitors, and the like. Typically, a flat panel display comprises a layer of liquid crystal material, acting as a phase-change material at each pixel, sandwiched between two plates. When power from a power source is applied across or through the liquid crystal material, the amount of light passing through the liquid crystal material is controlled (i.e., selectively modulated) at the pixel location, enabling the generation of an image on the display.

[0004] Conventional digital lithography systems can utilize one or more image projection systems. Each image projection system is configured to project one or more write beams onto a photoresist layer on the substrate surface. Each image projection system projects one or more write beams onto the substrate surface. The write beams, projected by a projection lens system, write a pattern (also called a mask pattern) into the photoresist layer on the substrate surface. However, due to vibrations within the digital lithography system, the writing of the corresponding image by the write beams results in roughness, sometimes leading to wavy or jagged patterns. In some cases, the roughness can have pitches as high as 10 nm to 10 μm. For example, vibration sources can be found in actuators present in digital lithography systems and air-handling systems, changing stagevelocity during image processing, air bearing flutter, and periodic resonance in the stagevelocity and eye-mount assembly.

[0005] Therefore, there is a need in the art for a method to stabilize images in order to reduce line roughness. Summary of the Invention

[0006] The method disclosed herein generally relates to an image stabilization method for digital lithography. The method includes: providing a spatial light modulator (SLM) in an image projection system, the SLM being positioned at a rotational angle relative to an in-scan direction, the SLM comprising a plurality of SLM pixels; and rasterizing a mask pattern for projection from the SLM, the mask pattern corresponding to a first group of SLM pixels among the plurality of pixels. A further implementation includes: detecting cross-scan vibration between the SLM and the substrate at a controller, the cross-scan vibration causing a cross-scan deviation; and in response to the detection, shifting the mask pattern within the SLM along the in-scan direction to a second group of SLM pixels to correct the cross-scan deviation.

[0007] Further embodiments disclosed herein generally relate to a system for digital lithography, including a processor and a memory, the memory including computer-readable instructions for image stabilization. The method includes: providing a spatial light modulator (SLM) in an image projection system, the SLM being positioned at a rotational angle relative to a lateral scanning direction, the SLM including a plurality of SLM pixels; and rasterizing a mask pattern for projection from the SLM, the mask pattern corresponding to a first group of SLM pixels among the plurality of pixels. A further embodiment includes: detecting cross-scan vibration between the SLM and a substrate at a controller, the cross-scan vibration causing a cross-scan deviation; and in response to the detection, shifting the mask pattern within the SLM along the lateral scanning direction to a second group of SLM pixels to correct for the cross-scan deviation.

[0008] The embodiments disclosed herein generally relate to non-transient computer-readable media, including computer-readable instructions for a method of image stabilization for digital lithography. Embodiments of the method include: providing a spatial light modulator (SLM) in an image projection system, the SLM being positioned at a rotational angle relative to a lateral scanning direction, the SLM including a plurality of SLM pixels; and rasterizing a mask pattern for projection from the SLM, the mask pattern corresponding to a first group of SLM pixels among the plurality of pixels. Further embodiments include: detecting cross-scan vibrations between the SLM and a substrate at a controller, the cross-scan vibrations causing cross-scan deviations; and in response to the detection, shifting the mask pattern within the SLM along the lateral scanning direction to a second group of SLM pixels to correct the cross-scan deviations. Attached Figure Description

[0009] Therefore, the above-described features of this disclosure can be understood in detail. A more specific description of this disclosure, which is briefly summarized above, can be obtained by referring to the embodiments, some of which are depicted in the accompanying drawings. However, it should be noted that the drawings illustrate only exemplary embodiments and should not be considered as limiting the scope of this disclosure, and other equivalent embodiments are permissible.

[0010] Figure 1 This is a perspective view of a digital lithography system according to a disclosed embodiment.

[0011] Figure 2 This is a schematic cross-sectional view of an image projection system according to the embodiments disclosed herein.

[0012] Figure 3 A perspective schematic diagram of several image projection systems according to the disclosed embodiments is depicted.

[0013] Figure 4 A perspective schematic diagram of an image projection system according to a disclosed embodiment is depicted.

[0014] Figure 5 An enlarged perspective view of two pixel elements of a spatial light modulator according to a disclosed embodiment is depicted.

[0015] Figure 6 The diagram schematically illustrates a beam of light reflected by two pixel elements of a spatial light modulator according to a disclosed embodiment.

[0016] Figure 7 An embodiment of the disclosed method is illustrated in which the platform passes under the spatial-temporal light modulator.

[0017] Figure 8 The correction of vibration in the transverse scanning direction according to the embodiment is described.

[0018] Figure 9 Image stabilization of positive subpixel cross-scan vibration according to the disclosed embodiment is described.

[0019] Figure 10 Image stabilization for negative subpixel cross-scan vibrations according to the disclosed embodiment is described.

[0020] Figure 11 A method for image stabilization according to a disclosed embodiment is described.

[0021] Figure 12 An example server in an image processing system according to the disclosed embodiments is described.

[0022] For ease of understanding, the same reference numerals have been used to denote common elements in the figures where possible. It is conceivable that elements and features of one embodiment may be advantageously incorporated into other embodiments without further description. Detailed Implementation

[0023] In the following description, reference is made to embodiments of this disclosure. However, it should be understood that this disclosure is not limited to the specifically described embodiments. Rather, any combination of the following features and elements, whether or not related to different embodiments, is contemplated for implementation and practice of this disclosure. Furthermore, while embodiments of this disclosure may achieve advantages over other possible solutions and / or over the prior art, whether a particular advantage is achieved by a given embodiment does not limit this disclosure. Therefore, the following aspects, features, embodiments, and advantages are merely exemplary and should not be considered elements or limitations of the appended claims unless expressly stated in the claims. Similarly, reference to “this disclosure” should not be construed as a generalization of any inventive subject matter disclosed herein and should not be considered an element or limitation of the appended claims unless expressly stated in the claims.

[0024] This disclosure provides a method for correcting the projection of an image from a spatial light modulator (SLM) onto a substrate when cross-scan vibration, including sub-pixel cross-scan vibration, is present.

[0025] In typical digital lithography systems, if lateral scanning vibration is detected, the image can be projected earlier or later to compensate for the vibration. However, if cross-scan vibration is detected, rasterizing the image in real time and providing that image to the SLM for projection onto the substrate is a computationally intensive process. Furthermore, previous techniques lacked a method to correct for this deviation if the cross-scan vibration was smaller than the number of pixels in the SLM.

[0026] In image projection systems, the SLM is provided at an angle relative to the lateral scanning direction. In some implementations, an angle of approximately 1° can correct for increments up to 1 / 100 of a pixel, while an angle of up to 26° can correct for increments up to [missing information]. 1The inventors discovered that, due to this angle, the SLM moves one pixel in the lateral scanning direction, resulting in a 1.5–2% pixel offset in the corresponding cross-scanning direction, which can be used to correct cross-scanning vibration. The amount of pixel offset can be determined by dividing the cross-scanning deviation by the tangent of the SLM rotation angle. For example, tan(1°) = 0.017 allows cross-scanning vibration correction in increments <1 / 50 pixels; similarly, 3° allows correction in increments <1 / 20 pixels, 5° allows correction in increments <1 / 10 pixels, 11° allows correction in increments <1 / 5 pixels, 14° allows correction in increments <1 / 4 pixels, 18° allows correction in increments <1 / 3 pixels, and 26° allows correction in increments <1 / 2 pixels. Cross-scanning vibration can be compensated for by subpixel distance by offsetting the rasterized image along the X-axis of the rotating SLM. Once offset, the image deviation only deviates from the intended target in the lateral scanning direction, therefore the projection time needs to be adjusted as described above. In some implementations, projection can be timed by setting the lateral scan direction coordinates of the substrate and triggering projection when the SLM reaches those coordinates. In the context of this document, in some implementations, "adjusting the projection timing" refers to changing the lateral scan coordinates at which projection is triggered. By leveraging the relative rotational position of the SLM with respect to the lateral scan direction, each image can be rasterized before the SLM reaches a given image destination. Furthermore, instead of requiring real-time re-rasterization to compensate for cross-scan vibrations, the provided image will be substantially tailored to the customer's design. This approach not only reduces the processing burden on processor and memory resources but also produces a more faithful representation of the predetermined customer design with lower line edge roughness.

[0027] Figure 1 This is a perspective view of a system 100 that can benefit from the embodiments disclosed herein. System 100 includes a base frame 110, a slab 120, a platform 130, and a processing device 160. The base frame 110 can be placed on the floor of a manufacturing facility and can support the slab 120. A passive air isolator 112 can be located between the base frame 110 and the slab 120. The slab 120 can be a single piece of granite, and the platform 130 can be disposed on the slab 120. A substrate 140 can be supported by the platform 130. A plurality of holes (not shown) can be formed in the platform 130 to allow a plurality of lifting rods (not shown) to extend therethrough. The lifting rods can rise to an extended position to receive the substrate 140, for example, from a transfer robot (not shown). The transfer robot can place the substrate 140 on the lifting rods, and then the lifting rods can gently lower the substrate 140 onto the platform 130.

[0028] The substrate 140 may be made of, for example, quartz and serve as part of a flat panel display. In other embodiments, the substrate 140 may be made of other materials. In some embodiments, the substrate 140 may have a photoresist layer formed on the substrate. The photoresist is radiation-sensitive and may be a positive or negative photoresist, meaning that after a pattern is written into the photoresist, those portions of the photoresist exposed to radiation will be either soluble or insoluble in the photoresist developer applied to the photoresist, respectively. The chemical composition of the photoresist determines whether it is a positive or negative photoresist. For example, the photoresist may include at least one of diazonaphthoquinone, phenol formaldehyde resin, poly(methyl methacrylate), poly(methyl glutarimide), and SU-8. In this way, patterns can be formed on the surface of the substrate 140 to form electronic circuitry.

[0029] System 100 may further include a pair of supports 122 and a pair of tracks 124. The supports 122 may be mounted on a plate 120, and both the plate 120 and the supports 122 may be a single piece of material. The tracks 124 may be supported by the supports 122, and the platform 130 may move along the tracks 124 in a lateral scanning direction. In one embodiment, the tracks 124 are a pair of parallel magnetic channels. As shown, each track 124 is straight. In other embodiments, the tracks 124 may have a non-linear shape. An encoder 126 or other sensor may be coupled to the platform 130 to provide position information to the controller 170 and to detect movement in the platform due to vibration. In some embodiments, the encoder 126 may be an interferometer or other device or sensor capable of detecting the position of the platform, vibration of the platform, and lateral and / or cross-scan deviations of the platform due to vibration.

[0030] The processing apparatus 160 may include a support 162 and a processing unit 164. The support 162 may be disposed on a flat plate 120 and may include an opening 166 for the platform 130 to pass beneath the processing unit 164. The processing unit 164 may be supported by the support 162. In one embodiment, the processing unit 164 is a pattern generator configured to expose photoresist in a photolithography process. In some embodiments, the pattern generator may be configured to perform a maskless photolithography process. The processing unit 164 may include a plurality of image projection systems 301 (shown in…) arranged in a housing 165. Figure 3The processing device 160 can be used to perform maskless direct patterning. During operation, such as... Figure 1 As shown, one of the platforms 130 moves from a loading position to a processing position along the lateral scanning direction. The processing position may refer to one or more positions of the platform 130 when it passes below the processing unit 164. During operation, the platform 130 may be supported by multiple air bearings 202 (shown in...). Figure 2 The air bearing is lifted and can be moved along the pair of rails 124 from the loading position to the handling position. Multiple vertically guided air bearings 202 (shown in...) Figure 2 The support can be coupled to platform 130 and positioned adjacent to the inner wall 128 of each support 122 to stabilize the movement of platform 130. Platform 130 can also be moved in the cross-scanning direction by moving along track 150 for processing and / or indexing substrate 140.

[0031] Figure 2 According to one implementation method Figure 1 A cross-sectional side view of system 100. As shown, platform 130 includes multiple air bearings 202 for lifting platform 130. Platform 130 may also include a motor coil (not shown) for moving platform 130 along track 124. Platform 130 and processing equipment 160 may be enclosed by a housing (not shown) to provide temperature and pressure control.

[0032] System 100 also includes a controller 170. This controller is typically designed to facilitate the control and automation of the processing techniques described herein. The controller may be coupled to, or communicate with, one or more of the processing device 160, platform 130, and encoder 126. The processing device 160 and platform 130 may provide the controller with information regarding substrate processing and substrate alignment. For example, the processing device 160 may provide information to the controller to alert it that substrate processing has been completed. The encoder 126 may provide position information to the controller, which is then used to control the platform 130 and processing device 160.

[0033] The controller may include a central processing unit (CPU) (not shown), memory (not shown), and support circuitry (or I / O) (not shown). The CPU may be any form of computer processor used in an industrial environment to control various processes and hardware (e.g., pattern generators, motors, and other hardware) and monitor these processes (e.g., processing time and substrate position). The memory (not shown) is connected to the CPU and may be one or more readily accessible memories, such as random access memory (RAM), read-only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. Software instructions and data may be encoded and stored in the memory to instruct the CPU. Support circuitry (not shown) is also conventionally connected to the CPU to support the processor. Support circuitry may include conventional caches, power supplies, clock circuits, input / output circuits, subsystems, and similar circuitry. A controller-readable program (or computer instructions) determines which tasks can be performed on the substrate. This program may be controller-readable software and may include code for monitoring and controlling, for example, processing time and substrate position.

[0034] Figure 3 This is a perspective view of multiple image projection systems 301 according to one embodiment. (See diagram below.) Figure 3 As shown, each image projection system 301 generates multiple write beams 302 along multiple tracks 310, projecting onto the surface 304 of the substrate 140 corresponding to multiple processing positions 312. Each track 310 is scanned by one or more write beams 302. The substrate 140 moves along the lateral scanning direction indicated by arrow 315, while the cross-scanning direction is indicated by arrow 320. As the substrate 140 moves along the lateral scanning direction and the cross-scanning direction, the entire surface 304 can be patterned by the write beams 302. The number of image projection systems 301 can vary based on the size of the substrate 140 and / or the speed of the platform 130. In one embodiment, the processing device 160 has 22 image projection systems 301.

[0035] Figure 4 According to one implementation method Figure 3 A perspective view of one of the multiple image projection systems 301.

[0036] Image projection system 301 includes a spatial light modulator (SLM) 410 and projection optics 416. These components of image projection system 301 vary depending on the SLM 410 used. SLM 410 includes, but is not limited to, arrays of microLEDs, VCSELs, liquid crystal displays (LCDs), or any solid-state emitters that emit electromagnetic radiation, as well as digital mirror devices (DMDs). SLM 410 includes a plurality of spatial light modulator pixels. Each of the plurality of SLM pixels is individually controllable and configured to project a write beam corresponding to one of the plurality of pixels (e.g., ...). Figure 5 , 6 (See Figures 7 and others). The compilation of multiple pixels forms a pattern written into the photoresist, referred to herein as a mask pattern. The projection optics 416 includes a projection lens, for example, a 10x objective lens, for projecting light onto the substrate 140. In operation, based on mask pattern data provided to the SLM 410 by the controller 170, each of the multiple SLM pixels is in an "on" or "off" position. Each SLM pixel in the "on" position forms a write beam, which is then projected by the projection optics 416 onto the surface of the photoresist layer on the substrate 140 to form a pixel of the mask pattern.

[0037] In one embodiment, the spatial light modulator 410 is a DMD. The image projection system 301 includes a light source 402, an aperture 404, a lens 406, a frustrated prism assembly 408, an SLM 410, and projection optics 416. In this embodiment, the SLM 410 includes a plurality of mirrors, i.e., a plurality of spatial light modulator pixels. Each of the plurality of mirrors corresponds to one pixel, which may correspond to one pixel of a mask pattern. In some embodiments, the DMD includes more than about 4,000,000 mirrors, while in other embodiments, the DMD may include 1920 × 1080 mirrors, which represents the number of pixels in a high-resolution television. The light source 402 is any suitable light source capable of producing light with a predetermined wavelength, such as a light-emitting diode (LED) or a laser. In one embodiment, the predetermined wavelength is in the blue or near-ultraviolet (UV) range, for example, less than about 450 nm. The frustrated prism assembly 408 includes a plurality of reflective surfaces. In operation, a light beam 403 with a predetermined wavelength is generated by a light source 402. The light beam 403 is reflected onto the DMD by a truncated prism assembly 408. When the light beam 403 reaches the mirrors of the DMD, each mirror in the "on" position reflects the light beam 403, i.e., forming a write beam, also known as a "shot," which is then projected onto the photoresist layer surface of the substrate 140 by projection optics 416. Multiple write beams 302 (also known as multiple shots) form multiple pixels of a mask pattern.

[0038] Figure 5 This is an enlarged perspective view of two pixel elements 502, 504 of an SLM 410 according to one embodiment. In an embodiment where the SLM 410 is a DMD, these pixel elements may be mirrors. As shown, each pixel element 502, 504 is arranged on a tilting mechanism 506, which is arranged on a memory cell 508. The memory cell 508 may be a CMOS SRAM. During operation, each pixel element 502, 504 is controlled by loading mask data into the memory cell 508. This mask data electrostatically controls the tilt of the pixel elements 502, 504 in a binary manner. When the pixel elements 502, 504 are in a reset mode or when no power is applied, the pixel elements 502, 504 are in a flat position that does not correspond to any binary position. Zero (0) in the binary may correspond to an “off” position, meaning that the pixel elements are tilted at -10 degrees, -12 degrees, or any other possible tilting manner in the negative direction. A binary digit (1) can correspond to an "on" position, meaning that the pixel element is tilted at +10 degrees, +12 degrees, or any other possible tilt in the positive direction. For example... Figure 5As shown, pixel element 502 is in the "off" position, while pixel element 504 is in the "on" position.

[0039] Figure 6 The schematic illustration shows the subject according to one embodiment. Figure 5 The two pixel elements 502 and 504 of the SLM 410 reflect the light beam 403. As shown, the pixel element 502 in the "off" position reflects the light beam 403 generated by the light source 402 to the light collector (liuht dump) 412. The pixel element 504 in the "on" position forms a write beam 302 by reflecting the light beam 403 to the projection lens 416, and then the projection lens 416 projects the light beam 403 onto the substrate 140.

[0040] Figure 7 One embodiment of the SLM 410 is schematically illustrated, wherein a platform 130 passes beneath the processing unit 164 and transports a substrate 140 beneath the image projection system 301 in a lateral scanning direction indicated by arrow 315, wherein the SLM 410 travels along a track 310 to project mask patterns at a plurality of processing positions 312. At each processing position 312, the pixel elements of the SLM 410 direct light toward or away from the respective pixels of the substrate 140 into a light collector 412.

[0041] The pixel elements 502, 504, etc. of the SLM 410 are arranged in an array. For example... Figure 7 As shown, SLM 410 is positioned substantially aligned, but not perfectly aligned, with substrate 140. The rotational offset of SLM 410 relative to substrate 140 defines the error. In some embodiments, the rotational offset of SLM 410 (e.g., the rotational offset of SLM axis 710 relative to the lateral scan direction of SLM 410 indicated by arrow 315) is approximately 1 degree (e.g., for a correction increment < 1 / 50 pixel), while in other embodiments, the rotational offset can range from 0.5 degrees to 26 degrees for correction increments ranging from 1 / 100 pixel to 0.5 pixel. The rotation of SLM 410 can be seen in the positioning of SLM axis 710. In embodiments, SLM axis 710 is offset from the lateral scan direction of the substrate by the same rotational angle as the rotational angle of SLM 410 from the lateral scan direction, and SLM axis 710 can be considered as the lateral scan axis of the SLM.

[0042] As the substrate 140 moves below the SLM 410, if a threshold area greater than that of each pixel on the substrate 140 lies below the SLM 410, the pixel elements 502, 504, etc., corresponding to the pixel at that location will receive an "on" (or "off" signal, depending on the image tone (e.g., photoresist type)). If a threshold area smaller than that of each pixel on the substrate 140 lies below the SLM 410, the pixel elements 502, 504, etc., corresponding to the pixel at that location will not receive an "off" (or "on" signal, depending on the image tone). This threshold area can be 50% of the pixel's surface area. In other threshold tests, the criterion can be whether the pixel centroid is inside or outside the geometry to be printed.

[0043] In one embodiment, the array of pixel elements 502, 504, etc., in the SLM 410 may be rectangular, wherein more pixel elements 502, 504 are arranged in the cross-scan direction than in the transverse scan direction, wherein the transverse scan direction substantially corresponds to the direction of movement of the platform 130, and therefore to the direction of movement of the substrate 140. In other embodiments, the SLM 410 may be square or any other shape.

[0044] For example, the ratio of the number of pixel elements 502, 504 arranged along the horizontal scanning direction to the number of pixel elements 502, 504 arranged along the cross scanning direction can be approximately 9:16, approximately 7:21, or approximately 3:4. In one embodiment, an SXGA+ type SLM provides 1400 mirror pixels in the Y direction and 1050 mirror pixels in the X direction, for a total of approximately 1.5 million mirror pixels and an aspect ratio (Y:X) of approximately 4:3. In another embodiment, a 1080P type SLM provides 1920 mirror pixels in the Y direction and 1080 mirror pixels in the X direction, for a total of approximately 2 million mirror pixels and an aspect ratio (Y:X) of approximately 16:9. In another embodiment, a WQXGA type SLM provides 2560 mirror pixels in the Y direction and 1600 mirror pixels in the X direction, for a total of approximately 4 million mirror pixels and an aspect ratio (Y:X) of approximately 16:10. In another embodiment, a 4K-type SLM provides 4096 mirror pixels in the Y direction and 2160 mirror pixels in the X direction, for a total of approximately 8 million mirror pixels, with an aspect ratio (Y:X) of approximately 17:9. In another embodiment, a similar 4K-type SLM can be constructed, but with half the number of SLM pixel elements in the horizontal scanning direction and twice the number of pixel elements in the cross-scan direction. This type of SLM, called a half-4K+half-4K type SLM, provides 8192 mirror pixels in the cross-scan direction and 1080 mirror pixels in the horizontal scanning direction, for a total of approximately 8 million mirror pixels, with an aspect ratio (cross-scan:horizontal scan) of approximately 68:9. In another embodiment, an SLM can be constructed that doubles the number of mirror pixels in both the horizontal and cross-scan directions. This type of SLM, called Full 4K+Full 4K type SLM, provides 8192 mirror pixels in the cross scan direction and 2160 mirror pixels in the horizontal scan direction, with a total of approximately 16 million mirror pixels and an aspect ratio (cross scan: horizontal scan) of approximately 34:9.

[0045] Other implementations may also be commercially feasible and / or available. For example, one implementation of the SLM may feature a total of 1080 pixel elements in the horizontal scanning direction and a total of 1920 pixel elements in the cross-scanning direction. In another implementation, the SLM may feature a total of 1600 pixel elements in the horizontal scanning direction and a total of 2560 pixel elements in the cross-scanning direction. In yet another implementation, the SLM may feature a total of 1960 pixel elements in the horizontal scanning direction and a total of 3880 pixel elements in the cross-scanning direction. In yet another implementation, the SLM may feature a 21:7 aspect ratio (cross-scan: horizontal scan).

[0046] Those skilled in the art will understand that other ratios are also possible. These embodiments share the common feature of providing a greater number of pixel elements in the scanning direction, which improves scanning efficiency. However, this particular ratio can be varied depending on the design and manufacturing function, as long as the number of pixel elements arranged in the cross-scanning direction is greater than the number of pixel elements arranged in the transverse scanning direction. In other embodiments, the number of pixel elements in the transverse scanning direction may be greater than the number in the cross-scanning direction, and in yet another embodiment, the number of pixel elements in each direction may be the same.

[0047] Figure 8 The correction 800 for vibration in the transverse scanning direction according to the embodiment is described.

[0048] The first example 801 depicts an SLM 410 approaching (not fully shown) a processing position 312 within a track 310 on a substrate 140, traveling in a lateral scanning direction as indicated by arrow 315, having a predetermined position for a mask pattern 805 that has been rasterized before reaching processing position 312. A controller 170 waits for the substrate 140 (moving relative to the SLM 410 in a direction opposite to the lateral scanning direction indicated by arrow 315) to reach an overlap position to place the mask pattern 805 at a target position 806. At this point, the controller 170 causes a light source 402 to flash onto the SLM 410 instantaneously, transferring the mask pattern 805 onto the target position 806 on the substrate 140.

[0049] The second example 810 depicts a mask pattern 805 to be printed at a desired target location 806 within the processing area 312. In this example, the controller 170 does not receive from the encoder 126 any indication that there will be vibration deviation when the SLM 410 is over the processing area 312. In this second example 810, radiation is projected onto the SLM 410, printing the mask pattern 805 onto the substrate 140 at the desired location. No modifications are required for offset of the mask pattern 805 or printing time delay in the SLM 410.

[0050] The third example 815 depicts a situation where the controller determines the presence of negative lateral scan vibration when the SLM 410 is above the processing area 312. Because the predicted position of the SLM 410 and the mask pattern 805 is offset by an amount 816 in the negative lateral scan direction, the controller delays the printing of the SLM 410, thereby causing the SLM 410 to be printed at the desired position, as shown in 818.

[0051] Fourth example 820 depicts a scenario predicted by controller 170 in which encoder 126 detects a positive lateral scan vibration that would result in a positive lateral scan offset 822 if no further action is taken. In response, as shown in 825, controller 170 accelerates the projection time, thereby causing SLM 410 to project mask pattern 805 at the desired location within processing area 312.

[0052] Figure 9 Image stabilization 900 for positive subpixel cross-scan vibration according to the disclosed embodiment is described.

[0053] Fifth example 901 depicts a situation where, based on data from encoder 126, the controller predictably determines the presence of positive cross-scan vibration when SLM 410 is above processing area 312. It can be seen that, without any action, mask pattern 805 will be projected and misaligned with the desired target position.

[0054] In existing methods, when cross-scan vibration is equal to (or close to) an offset equal to or close to the SLM pixel size, the mask pattern 805 is rerasterized, repositioned, or offset on the SLM 410 in SLM pixel increments along the cross-scan direction. In the absence of lateral scan vibration, the SLM 410 is instructed to project the offset mask pattern 805 onto the desired target position 806. However, since the mask pattern 805 can only be offset in full SLM pixel increments, the placement error in the cross-scan direction must be rounded to the nearest 0.5 pixel, resulting in image blurring, overlay error, or line-edge roughness. Consequently, without the benefits of the present disclosure, digital lithography tools would need to optically reduce the pixel pitch to a smaller field size, reducing tool yield.

[0055] Sixth example 905 depicts the correction of sub-pixel deviation in the orthogonal cross-scan direction according to the disclosed embodiment. In this example, as in fifth example 901, controller 170 has received data from encoder 126 indicating orthogonal cross-scan vibration. The sixth example shows where mask pattern 805 would be projected if no action is taken.

[0056] Controller 170 instructs image projection system 165 to offset the mask pattern 805 on SLM 410 along axis 710. As described above, because SLM 410 is rotated by an angle relative to the lateral scan direction 315, offsetting the mask pattern 805 along SLM axis 710 as indicated by arrow 907 will, for each pixel offset in the SLM axis 710 direction, further offset the mask pattern 805 in the cross-scan direction by 1.5-2%. As a result, mask pattern 805 is offset to the offset mask pattern 906 position, correcting for cross-scan vibration. At this time, the offset mask pattern 906 position can be corrected in a manner similar to the fourth example 820 described above by having controller 170 instruct image projection system 165 to accelerate the projection time on SLM 410, so as to place the offset mask pattern 805 at the desired target position 806. In some embodiments, projection can be timed by setting the lateral scan direction coordinates of the substrate and triggering projection when the SLM reaches those coordinates. In this context, in some implementations, "adjusting the timing of the projection" refers to changing the lateral scan coordinates at which the projection is triggered.

[0057] Figure 10 Image stabilization for negative subpixel cross-scan vibrations according to the disclosed embodiments is described.

[0058] Seventh example 1005 depicts the correction of sub-pixel deviation in the negative cross-scan direction according to the disclosed embodiment. In this example, controller 170 has received data from encoder 126 indicating negative cross-scan vibration. The seventh example shows where mask pattern 805 would be projected if no action is taken.

[0059] Controller 170 instructs image projection system 165 to offset mask pattern 805 on SLM 410 in the negative direction of SLM axis 710. As described above, because SLM 410 is rotated by an angle relative to the lateral scan direction 315, offsetting mask pattern 805 along SLM axis 710 as shown by arrow 1003 will, for each pixel offset in the SLM axis 710 direction, further offset mask pattern 805 in the cross-scan direction by 1.5-2% (approximately 1 degree rotation of SLM in the embodiment). As a result, mask pattern 805 is offset to the offset mask pattern 1006 position, correcting for negative cross-scan vibration. At this time, the position of the offset mask pattern 1006 can be corrected in a manner similar to the third example 815 described above by having controller 170 instruct image projection system 165 to delay the projection time on SLM 410, so as to place the offset mask pattern 805 at the desired target position 806. In some implementations, projection can be timed by setting the lateral scan direction coordinates of the substrate and triggering projection when the SLM reaches those coordinates. In this context, in some implementations, "adjusting the projection time" refers to changing the lateral scan coordinates at which projection is triggered.

[0060] Figure 11 A method 1100 for image stabilization according to the disclosed embodiments is described.

[0061] At 1110, the method provides a spatial light modulator (SLM) in the image projection system, which is positioned with respect to the lateral scanning direction by a rotation angle, the spatial light modulator comprising a plurality of SLM pixels. In some embodiments, the rotation angle can be from 0.5 degrees to 26 degrees, while in some embodiments, the rotation angle is about 1 degree. For example, tan(1°) = 0.017 allows for cross-scan vibration correction in increments <1 / 50 pixels; similarly, 3° allows for correction in increments <1 / 20 pixels, 5° allows for correction in increments <1 / 10 pixels, 11° allows for correction in increments <1 / 5 pixels, 14° allows for correction in increments <1 / 4 pixels, 18° allows for correction in increments <1 / 3 pixels, and 26° allows for correction in increments <1 / 2 pixels.

[0062] In 1120, method 1100 further includes: rasterizing a mask pattern for projection from the SLM, the mask pattern corresponding to a first group of SLM pixels among a plurality of SLM pixels.

[0063] In 1130, the method includes: detecting cross-scan vibration between the SLM and the substrate at a controller, the cross-scan vibration causing cross-scan deviation. In some embodiments, the detected cross-scan vibration is less than that of one SLM pixel among a plurality of SLM pixels.

[0064] In 1140, method 1100 further includes: in response to the detection, in the lateral scanning direction, in some embodiments, offsetting a mask pattern within the SLM to a second set of SLM pixels along an axis (e.g., the lateral scanning axis) that is primarily parallel to the lateral scanning direction of the SLM 710, to correct for cross-scan deviation, and making a corresponding change to the lateral scan exposure location after offsetting the mask pattern. In some embodiments, the amount of offset of the mask pattern along the SLM axis is determined by dividing the cross-scan deviation by the tangent of the rotation angle. In an embodiment with a nominal 1-degree SLM rotation, offsetting the mask pattern on the SLM by one pixel along the SLM axis corrects for a 1.7% pixel cross-scan deviation.

[0065] In an implementation, method 1100 further includes: providing radiation to an SLM for projecting a mask pattern onto a substrate, including performing one of the following delay and acceleration steps based on detection: delaying and accelerating the time of providing radiation to the SLM.

[0066] Figure 12 An example server 1200 in an image processing system is depicted, which is capable of performing the methods described herein, such as those concerning... Figures 1 to 11 The image stabilization method is described.

[0067] Server 1200 includes a central processing unit (CPU) 1202 connected to a data bus 1216. CPU 1202 is configured to process, for example, computer-executable instructions stored in memory 1208 or storage 1210, and cause server 1200 to perform, for example, actions related to… Figures 1 to 11 The methods described herein. CPU 1202 is included to represent a single CPU, multiple CPUs, a single CPU having multiple processing cores, and other forms of processing architecture capable of executing computer-executable instructions.

[0068] Server 1200 further includes: input / output (I / O) device 1212 and interface 1204, interface 1204 allowing server 1200 to interface with input / output device 1212, for example, to input / output from encoder 126 such as, for example, platform position data (e.g., real-time and / or instantaneous platform position data), such as lateral scan position data (e.g., x-coordinate position data) and cross scan position data (e.g., y-coordinate position data), to provide patterns to an SLM such as SLM 410 in image projection system 301, and to input / output data to control a light source such as light source 402, keyboard, display, mouse device, pen input device, and other devices that allow interaction with server 1200. It should be noted that server 1200 can be connected to external I / O devices (e.g., external display devices) via physical and wireless connections.

[0069] Server 1200 further includes network interface 1206, which provides server 1200 with access to external network 1214, thereby providing access to external computing devices.

[0070] Server 1200 further includes memory 1208, which in this example includes storage for execution. Figure 1-11 The operation described herein includes a provisioning module 1218, a rasterization module 1220, a detection module 1222, an offset module 1224, a correction module 1226, a delay module 1228, and an acceleration module 1229. Although in Figure 12 The rasterization module 1220 is shown residing in memory, but in some implementations, one or more modules may be implemented in software, hardware, or a combination of software and hardware. In some implementations, such hardware may be programmable hardware such as an FPGA. In some implementations, the rasterization module 1220 is in (or connected to) one or more graphics processing units (GPUs).

[0071] It should be noted that, although for simplicity... Figure 12 A single memory 1208 is shown, but the various aspects stored in memory 1208 can be stored in different physical memories, including memories located away from server 1200, but all of these are accessible via internal data connections such as bus 1216 through CPU 1202.

[0072] The storage 1210 further includes mask pattern data 1230, cross-scan vibration data 1232, and cross-scan deviation data 1234, which can be similar to Figure 1-11As described in [the document]. In some embodiments, the cross-scan vibration data 1232 and the cross-scan deviation data 1234 may be provided by one or more sensors such as encoder 126.

[0073] Despite Figure 12 It is not shown in the diagram, but other aspects may be included in the storage 1210.

[0074] Similar to memory 1208, for simplicity, Figure 12 A single storage device 1210 is shown, but the various aspects stored in storage device 1210 can be stored in different physical storage devices, all of which are accessible to CPU 1202 via internal data connections such as bus 1216 or external connections such as network interface 1206. Those skilled in the art will understand that one or more components of server 1200 can be located remotely and are accessible via network 1214.

[0075] The foregoing description is provided to enable those skilled in the art to practice the various embodiments described herein. The examples discussed herein do not limit the scope, applicability, or implementation set forth in the claims. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments. For example, the function and arrangement of the discussed elements can be changed without departing from the scope of this disclosure. Various processes or components can be suitably omitted, substituted, or added in various examples. For example, the described methods can be performed in a different order than described, and various steps can be added, omitted, or combined. Moreover, features described with respect to some examples can be combined in some other examples. For example, an apparatus or method can be implemented using any number of aspects set forth herein. Furthermore, the scope of this disclosure is intended to cover such apparatuses or methods practiced using structures, functions, or structures and functions other than, or alternative to, the various aspects of this disclosure set forth herein. It should be understood that any aspect of this disclosure may be embodied by one or more elements of the claims.

[0076] As used herein, the phrase “at least one of a list of items” refers to any combination of those items, including a single member. For example, “at least one of a, b, or c” is intended to cover: a, b, c, ab, ac, bc, and abc, as well as combinations with multiple identical elements (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc, and ccc, or any other order of a, b, and c).

[0077] As used herein, the term "determining" encompasses a wide variety of actions. For example, "determining" can include calculating, computation, processing, derivation, research, searching (e.g., searching in a table, database, or other data structure), ascertaining, and the like. Furthermore, "determining" can include receiving (e.g., receiving information), accessing (e.g., accessing data in memory), and the like. Moreover, "determining" can include parsing, selecting, choosing, establishing, and similar actions.

[0078] The methods disclosed herein include one or more steps or actions for implementing these methods. These method steps and / or actions may be interchanged with each other without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and / or use of a particular step and / or action may be modified without departing from the scope of the claims. Furthermore, various operations of the above methods can be performed by any suitable means capable of performing the corresponding functions. Such means may include various hardware and / or software components and / or modules, including but not limited to circuits, application-specific integrated circuits (ASICs), or processors. Typically, in the case of illustrated operations, those operations may have correspondingly paired means-plus-function components with similar numbering.

[0079] The various illustrative logic blocks, modules, and circuits described in connection with this disclosure may be implemented or executed by a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic device, discrete hardware component, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but alternatively, the processor may be any commercially available processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0080] The processing system can be implemented using a bus architecture. Depending on the specific application and overall design constraints of the processing system, the bus can include any number of interconnect buses and bridges. The bus can link together various circuits, including processors, machine-readable media, and input / output devices. User interfaces (e.g., keyboards, displays, mice, joysticks, etc.) can also be connected to the bus. The bus can also link various other circuits, such as timing sources, peripherals, voltage regulators, power management circuits, and other circuit elements well known in the art, and therefore will not be described further. The processor can be implemented as one or more general-purpose processors and / or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuits that can execute software. Those skilled in the art will recognize how best to implement the described functionality for the processing system, given the specific application and the overall design constraints imposed on the system.

[0081] If implemented in software, these functions can be stored or transmitted as one or more instructions or code on a computer-readable medium. Software should be broadly interpreted to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or others. Computer-readable media includes both computer storage media and communication media, such as any medium that facilitates the transfer of a computer program from one place to another. The processor may be responsible for managing the bus and general processing, including executing software modules stored on the computer-readable storage medium. The computer-readable storage medium may be coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Alternatively, the storage medium may be integrated with the processor. For example, a computer-readable medium may include a transmission line, a carrier wave modulated by data, and / or a separate computer-readable storage medium with instructions stored thereon, all of which can be accessed by the processor via a bus interface. Alternatively or additionally, a computer-readable medium or any part thereof may be integrated into the processor, such as in the form of a cache and / or a general-purpose register file. Examples of machine-readable storage media may include, for example, RAM (random access memory), flash memory, ROM (read-only memory), PROM (programmable read-only memory), EPROM (erasable programmable read-only memory), EEPROM (electrically erasable programmable read-only memory), registers, disks, optical disks, hard disks, or any other suitable storage media, or any combination thereof. Machine-readable media may be embodied in a computer program product.

[0082] Software modules may include single or multiple instructions and may be distributed across several different code segments, within different programs, and across multiple storage media. Computer-readable media may include several software modules. These software modules include instructions that, when executed by a device such as a processor, cause the processing system to perform various functions. Software modules may include transfer modules and receive modules. Each software module may reside in a single storage device or may be distributed across multiple storage devices. For example, a software module may be loaded from a hard disk drive into RAM when a triggering event occurs. During the execution of a software module, the processor may load some instructions into a cache to improve access speed. One or more cache lines may then be loaded into a general-purpose register file for execution by the processor. When referring to the function of a software module, it will be understood that such function is implemented by the processor when instructions from that software module are executed.

[0083] The appended claims are not intended to be limited to the embodiments shown herein, but should be granted the full scope consistent with the language of the claims. In a claim, unless specifically stated otherwise, reference to an element in the singular form is not intended to mean “one and only one,” but rather “one or more.” Unless expressly stated otherwise, the term “some” means one or more. No element of a claim should be interpreted in accordance with the provisions of section 112(f) of the U.S. Patent Code, unless the element is explicitly stated using the phrase “means for,” or, in the case of a method claim, using the phrase “for a step.” All structural and functional equivalents of elements throughout the various aspects described in this disclosure that are known or will be known hereafter by one of ordinary skill in the art are expressly incorporated herein by reference and are intended to be covered by the claims. Furthermore, nothing disclosed herein is intended to be offered to the public, whether or not such disclosure is expressly stated in the claims.

Claims

1. A method for image stabilization in digital lithography, comprising the following steps: A spatial light modulator (SLM) is provided, the spatial light modulator being positioned at a rotational angle relative to the lateral scanning direction, the spatial light modulator comprising a plurality of SLM pixels; A rasterized mask pattern is formed to create a rasterized mask pattern for projection from the SLM, the mask pattern corresponding to a first group of SLM pixels among the plurality of SLM pixels; The cross-scan deviation between the SLM and the substrate is detected at the controller. and The cross-scan deviation is corrected by shifting the rasterized mask pattern within the SLM along the lateral scanning direction to the second group of SLM pixels, thereby changing the lateral scanning coordinates where the rasterized mask pattern is projected.

2. The method of claim 1, wherein changing the lateral scan coordinates at which the rasterized mask pattern is projected includes adjusting the time at which the rasterized mask pattern is projected.

3. The method of claim 2, wherein adjusting the time of the projection comprises: Based on the detection, one of the following is determined: delaying the projection time or accelerating the projection time.

4. The method of claim 3, further comprising the following steps: The offset of the rasterized mask pattern along the axis of the SLM is determined by dividing the cross-scan deviation by the tangent of the rotation angle.

5. The method of claim 4, wherein the rotation angle is from 0.5 degrees to 26 degrees.

6. The method of claim 4, wherein the rotation angle is approximately 1 degree.

7. The method of claim 4, wherein the step of providing the SLM comprises: The mask data is loaded into the memory cell of the SLM; and The tilting mechanism of the SLM is used to tilt the pixel elements of the SLM.

8. A system for digital lithography, comprising: Platform, which is configured as a supporting substrate; The processing device includes multiple image processing systems, each of which includes: A spatial light modulator (SLM) is positioned at a rotational angle relative to a lateral scanning direction and includes a plurality of SLM pixels, wherein the SLM is configured as a projected rasterized mask pattern, the rasterized mask pattern corresponding to a first group of SLM pixels among the plurality of SLM pixels; and The controller is configured to: Detecting the cross-scan deviation between the SLM and the substrate; and In response to the detection, the cross-scan deviation is corrected by changing the lateral scan coordinates of the rasterized mask pattern being projected, thereby shifting the rasterized mask pattern within the SLM to the second group of SLM pixels along the lateral scan direction. This is to correct the cross-scan deviation.

9. The system for digital lithography as claimed in claim 8, wherein changing the lateral scan coordinates at which the rasterized mask pattern is projected includes adjusting the time at which the rasterized mask pattern is projected.

10. The system for digital lithography as claimed in claim 8, wherein the controller is further configured to determine the offset of the rasterized mask pattern along the axis of the SLM by dividing the cross-scan deviation by the tangent of the rotation angle.

11. The system for digital lithography as claimed in claim 10, wherein the rotation angle is from 0.5 degrees to 26 degrees.

12. The system for digital lithography as claimed in claim 11, wherein the rotation angle is approximately 1 degree.

13. The system for digital lithography as claimed in claim 11, further comprising: The memory cell of the SLM is configured to load mask data; and The tilting mechanism of the SLM is configured to tilt the pixel elements of the SLM in response to the mask data, so that the SLM is positioned with a rotational angle relative to the lateral scanning direction.

14. A processing apparatus, comprising: Multiple image processing systems, the image processing systems including: A spatial light modulator (SLM), positioned at a rotational angle relative to a lateral scanning direction, and comprising a plurality of SLM pixels, wherein the SLM is configured as a projected rasterized mask pattern corresponding to a first group of SLM pixels among the plurality of SLM pixels; and The controller is configured to: Detecting the cross-scan deviation between the SLM and the substrate; and In response to the detection, the cross-scan deviation is corrected by changing the lateral scan coordinates of the rasterized mask pattern being projected, thereby shifting the rasterized mask pattern within the SLM to the second group of SLM pixels along the lateral scan direction. This is to correct the cross-scan deviation.

15. The processing apparatus of claim 14, wherein changing the lateral scan coordinates at which the rasterized mask pattern is projected includes adjusting the time at which the rasterized mask pattern is projected.

16. The processing apparatus of claim 14, wherein the controller is further configured as a rasterized mask pattern to form the rasterized mask pattern.

17. The processing apparatus of claim 14, wherein the controller is further configured to determine the offset of the rasterized mask pattern along the axis of the SLM by dividing the cross-scan deviation by the tangent of the rotation angle.

18. The processing apparatus of claim 17, wherein the rotation angle is from 0.5 degrees to 26 degrees.

19. The processing apparatus of claim 17, wherein the rotation angle is approximately 1 degree.

20. The processing apparatus of claim 15, further comprising: The memory cell of the SLM is configured to load mask data; and The tilting mechanism of the SLM is configured to tilt the pixel elements of the SLM in response to the mask data, so that the SLM is positioned with a rotational angle relative to the lateral scanning direction.

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