Digital Lithography Scan Sequencing

Abstract

The digital lithography system includes adjacent scan areas, an exposure unit located above the scan areas, a memory, and a processing device operatively coupled to the memory. The exposure units include a first exposure unit associated with the first scan area and a second exposure unit associated with the second scan area. The processing device is for initiating a digital lithography process to pattern a substrate disposed on a stage according to instructions. The processing device further performs a first pass of the first exposure unit on a stitching area at a boundary between the first scan area and the second scan area at a first time. The processing device further performs a second pass of the second exposure unit on the stitching area at a second time that differs from the first time by less than 40 seconds.

Description

[Technical Field]

[0001]

[0001] This disclosure relates generally to electronic device manufacturing. More particularly, this disclosure relates to digital lithography. [Background technology]

[0002]

[0002] Photolithography is used in the manufacture of semiconductor devices and display devices, such as flat panel display devices. Examples of flat panel display devices include thin film display devices, such as liquid crystal display (LCD) devices and organic light emitting diode (OLED) display devices. Large area substrates can be used to manufacture flat panel display devices used in computers, touch panel devices, personal digital assistants (PDAs), mobile phones, television monitors, etc.

[0003]

[0003] In digital lithography, multiple exposure units are used to increase throughput, with each exposure unit covering a portion of the print area. However, scanning delays at boundaries can cause anomalies in the formed features. As a result, visible boundaries can occur between areas printed by different exposure units. For display devices, visible boundaries are defects that can cause the manufactured display to be discarded. Summary of the Invention

[0004]

[0004] The following is a simplified summary of the present disclosure to provide a basic understanding of some aspects of the disclosure. This summary is not an exhaustive overview of the disclosure. It is not intended to identify key or critical elements of the disclosure, nor is it intended to delineate the scope of any particular embodiments of the disclosure or the scope of the claims. The sole purpose of this summary is to present some concepts of the disclosure in a simplified form as a prelude to the more detailed description that is presented later.

[0005] According to at least one embodiment, a digital lithography system is provided. The digital lithography system includes multiple scan areas, including a first scan area and a second scan area adjacent to the first scan area. The digital lithography system further includes multiple exposure units positioned above the multiple scan areas. The multiple exposure units include a first exposure unit associated with the first scan area and a second exposure unit associated with the second scan area. The digital lithography system further includes a memory and at least one processing device operatively coupled to the memory. The at least one processing device is configured to initiate a digital lithography process to pattern a substrate disposed on a stage according to instructions. The at least one processing device is further configured to perform a first pass of the first exposure unit on a stitching area at a boundary between the first scan area and the second scan area at a first time. The at least one processing device is further configured to perform a second pass of the second exposure unit on the stitching area at a second time that differs from the first time by less than 40 seconds.

[0006] According to at least one embodiment, a system is provided. The system includes a memory and at least one processing device operably coupled to the memory. The at least one processing device is for initiating a digital lithography process to pattern a substrate according to instructions. The at least one processing device is further for performing a first pass of a first exposure unit over a stitching area at a boundary between a first scan area of ​​the plurality of scan areas and a second scan area of ​​the plurality of scan areas at a first time. The at least one processing device is further for performing a second pass of a second exposure unit over the stitching area at a second time that differs from the first time by less than 40 seconds.

[0007] According to at least one embodiment, a method is provided. The method includes a digital lithography process for patterning a substrate initiated by a processing device in accordance with instructions. The method further includes performing a first pass of a first exposure unit over a stitching area at a boundary between a first scan area of ​​the plurality of scan areas and a second scan area of ​​the plurality of scan areas at a first time. The method further includes performing a second pass of a second exposure unit over the stitching area at a second time that differs from the first time by less than 40 seconds.

[0008] Aspects and embodiments of the present disclosure will become more fully understood from the following detailed description and the accompanying drawings, which are intended to illustrate aspects and embodiments by way of example and not by way of limitation. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a top-down view of a digital lithography system according to some embodiments. [Figure 2A]

[0010] FIG. 1 is a top-down view illustrating a scanning path of a substrate through a single digital lithography exposure unit of a digital lithography system, according to some embodiments. [Figure 2B] FIG. 1 is a top-down view illustrating a scan path of a substrate through a single digital lithography exposure unit of a digital lithography system according to some embodiments. [Figure 2C] FIG. 1 is a top-down view illustrating a scanning path of a substrate through a single digital lithography exposure unit of a digital lithography system, according to some embodiments. [Figure 2D] FIG. 1 is a top-down view illustrating a scanning path of a substrate through a single digital lithography exposure unit of a digital lithography system, according to some embodiments. [Figure 3A]

[0011] FIG. 1 is a top-down view illustrating a scanning path of a substrate through a single digital lithography exposure unit of a digital lithography system, according to some embodiments. [Figure 3B] FIG. 1 is a top-down view illustrating a scanning path of a substrate through a single digital lithography exposure unit of a digital lithography system, according to some embodiments. [Figure 3C] FIG. 1 is a top-down view illustrating a scanning path of a substrate through a single digital lithography exposure unit of a digital lithography system, according to some embodiments. [Figure 3D] FIG. 1 is a top-down view illustrating a scanning path of a substrate through a single digital lithography exposure unit of a digital lithography system, according to some embodiments. [Figure 4A]

[0012] 1A-1C illustrate examples of boundary smoothing in a digital lithography exposure unit, according to some embodiments. [Figure 4B] 1A-1C illustrate examples of boundary smoothing in a digital lithography exposure unit, according to some embodiments. [Figure 4C] 1A-1C illustrate examples of boundary smoothing in a digital lithography exposure unit, according to some embodiments. [Figure 5]

[0013] FIG. 1 illustrates an exemplary scanning configuration of a digital lithography exposure unit in a one-bridge implementation, according to some embodiments. [Figure 6A]

[0014] 1 is a diagram of an exemplary scan sequence of a digital lithography exposure unit with respect to time, according to some embodiments. [Figure 6B] 1 is a diagram of an exemplary scan sequence of a digital lithography exposure unit with respect to time, according to some embodiments. [Figure 7]

[0015] 1A-1C illustrate features formed on a substrate by a digital lithography process according to some embodiments. [Figure 8]

[0016] 1 is a flowchart of a method for implementing digital lithography scan sequencing, according to some embodiments. [Figure 9]

[0017] FIG. 1 is a block diagram of a digital lithography system, according to some embodiments. [Figure 10]

[0018] FIG. 1 is a block diagram illustrating a computer system, in accordance with certain embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0010]

[0019] Digital lithography can be used to generate patterns (e.g., for digitally aligned etch masks) on a substrate surface without the use of a photomask (e.g., via maskless lithography). Digital lithography technology (e.g., Texas Instruments® programmable light control technology) enables high-speed, high-resolution maskless lithography solutions for printed circuit board (PCB) patterning, solder masks, flat panel displays, laser marking, and other digital exposure systems requiring high speed and precision. Digital lithography is used to directly expose patterns onto a photoresist film without the use of a contact mask (e.g., a photomask). This reduces material costs, improves production rates, and allows for rapid pattern changes. Direct exposure increases productivity compared to narrow laser beam or mask methods. An advantage of digital lithography is that lithographic patterns can be changed from one process to the next without incurring the cost of creating a new photomask. For example, digital lithography can be used to perform large-area patterning during electronic device manufacturing.

[0011]

[0020] In digital lithography, multiple digital lithography exposure units (“exposure units”) can be used to increase the throughput of a digital lithography tool. Conventional exposure units can print or expose rectangular, non-overlapping areas, or clipping layers. The clipping layers can act as filters that tell layout processing software to keep the pattern printed by a particular exposure unit on the clipping layer associated with that exposure unit. Multiple exposure units may each be responsible for a portion of the print area and a different clipping layer. Scans at the boundaries of exposure units may experience delays between one scan and another. This delay can result in non-uniformities (bumps, inconsistencies, irregularities, etc.) at the boundaries of the exposure units (e.g., “stitching areas”). This non-uniformity can reduce yield and reduce value.

[0012]

[0021] Exposure units often sequentially scan some sub-regions of the print area to increase throughput. For example, an exposure unit may scan a first portion of the print area, followed by an adjacent second portion, an adjacent third portion, and so on. Because adjacent exposure units move together across the print area, sequential scanning of sub-regions of the print area causes delays in scanning by adjacent exposure units at their boundaries (e.g., in stitching regions). This scanning delay can cause anomalies in the features formed by the scan. These anomalies can cause variations in critical dimensions, resulting in scrapped products and reduced overall yield.

[0013]

[0022] Aspects and embodiments of the present disclosure address these and other shortcomings of existing technologies by using digital lithography scan sequencing to perform scanning to reduce the delay between scans of the stitching region at the boundary between exposure unit boundaries. Reducing the delay between scans of the stitching region reduces anomalies in features printed in the stitching region, resulting in a gradual transition between pairs of exposure units. At least two different scan sequences may be used to perform digital lithography scanning in accordance with the embodiments described herein. In some embodiments, an inside-to-outside scan sequence may be performed such that the stitching region at the boundary of two adjacent scan regions is scanned sequentially by two adjacent exposure units, one scan followed by the next. In some embodiments, an outside-to-inside scan sequence may be similarly performed. Scanning the stitching region first with a first exposure unit and then with a second exposure unit reduces the delay between scans, resulting in more uniform features being formed on the substrate, particularly in the stitching region. In some embodiments, the delay between scanning the stitching area with the first exposure unit and scanning the stitching area with the second exposure unit is less than 40 seconds.

[0014]

[0023] In some embodiments, a first sub-region near an edge of a scan region of a first exposure unit, for example within an exposure unit boundary, is scanned, followed by a second sub-region near the opposite edge of the scan region. The first and second sub-regions may be stitching regions associated with the scan region and an adjacent scan region. A third sub-region is scanned near the first sub-region, then a fourth sub-region is scanned near the second sub-region, and so on until all sub-regions of the scan region have been scanned. The above-described sequence may be referred to as an outside-to-inside scanning sequence. Further details regarding the outside-to-inside scanning sequence are described herein below with reference to Figures 2A-2D.

[0015]

[0024] In some embodiments, a first sub-region of the scan region (e.g., an inner sub-region, a central sub-region, etc.) near the centerline of the scan region is scanned, followed by a second sub-region near the first sub-region. Then, a third sub-region is scanned near the first sub-region and on the opposite side of the first sub-region from the second sub-region. Scanning continues until sub-regions at both ends of the scan region have been scanned. The end sub-regions may be stitching regions associated with the scan region and adjacent scan regions. The above-described sequence may be referred to as an inside-to-outside scanning sequence. Further details regarding the inside-to-outside scanning sequence are described below with reference to Figures 3A-3D.

[0016]

[0025] Aspects and implementations of the present disclosure result in technical advantages over other approaches. For example, as previously described, non-uniformities at the boundaries of adjacent pairs of exposure units (e.g., stitching regions) and / or at the boundaries of a pair of scans associated with a given exposure unit may be reduced. Accordingly, improved photolithography for patterning substrates may be achieved.

[0017]

[0026] FIG. 1 is a top-down view of a digital lithography system (“system”) 100, according to some embodiments. As shown, the digital lithography system 100 includes a stage assembly 110, which includes a base (e.g., a granite base), a stage, and a substrate disposed on the stage. The substrate may be a glass plate, a wafer, a PCB, or other type of substrate. The substrate may correspond to or be positioned within a digital lithography print area or scan area, which has multiple scan areas, including scan areas 112-1 through 112-4. The left portion of the stage assembly 110 corresponds to a first bridge 114-1 above the stage assembly 110, and the right portion of the stage assembly 110 corresponds to a second bridge 114-2 above the stage assembly 110. Exposure units are attached to the bridges 114-1 and 114-2. In some embodiments, the length of each of the bridges 114-1 and 114-2 may range between approximately 500 mm (millimeters) and approximately 1000 mm. For example, the length of each of the bridges 114-1 and 114-2 may be approximately 750 mm.

[0018]

[0027] The substrate may include a photoresist material disposed over the material to be etched. The photoresist material may be a positive-tone photoresist material (i.e., portions of the photoresist material exposed to light become soluble in a photoresist developer) or a negative-tone photoresist material (i.e., portions of the photoresist material exposed to light become insoluble in a photoresist developer). Thus, a photoresist pattern may be formed by removing designated portions of the photoresist material. In some embodiments, the material to be etched is a conductive material (e.g., a metal). For example, the conductive material may be molybdenum. After designated areas of the photoresist material are removed, the now-exposed material may be etched according to the photoresist pattern. For example, wiring may be formed during the etching process. Alternatively, the patterned material itself may be photosensitive, eliminating the need for an additional photoresist layer prior to the subsequent etching process.

[0019]

[0028] To perform the photoresist patterning, digital lithography system 100 further includes a first column of digital lithography exposure units (“exposure units”) suspended from first bridge 114-1 and a second column of exposure units suspended from second bridge 114-2. For example, the first column of exposure units includes exposure units 1-11, and the second column of exposure units includes exposure units 12-22. Thus, in this illustrative example, a total of 22 exposure units are shown. However, the number of exposure units shown in FIG. 1 should not be considered limiting, and digital lithography system 100 can include any suitable number of exposure units in accordance with embodiments described herein.

[0020]

[0029] Each exposure unit may include a lens assembly capable of projecting an image onto the photoresist material of the substrate. Each lens assembly is shown adjacent the bottom right corner of its associated scan area. For example, lens assembly 120 of exposure unit 1 is associated with scan area 112-1. In some embodiments, each lens assembly is approximately 4 mm high and approximately 3 mm wide. However, each lens assembly may have any suitable dimensions in accordance with embodiments described herein.

[0021]

[0030] During the digital lithography process, each exposure unit is moved relative to the substrate to expose an area (e.g., a rectangular area) of the substrate to electromagnetic radiation, such as light (e.g., ultraviolet light, near-ultraviolet light). During scanning, the exposure units expose their respective scan areas according to a programmed scan path. Instead of moving the exposure units around the periphery of the stage assembly 110, the stage assembly 110 may move in the X and Y directions below the exposure units according to a programmed scan path. Because the field of view of a lens assembly (e.g., lens assembly 120) may be smaller than its associated scan area (e.g., scan area 112-1), the stage assembly 110 may need to move back and forth repeatedly until the entire scan area (e.g., scan area 112-1) is printed. The lens assembly 120 is designed to scan the scan area 112-1, excluding the first and last scans, which may be cropped based on the definition of the scan area 112-1. A larger number of exposure units may correspond to a higher throughput by performing fewer scans.

[0022]

[0031] Each exposure unit may be responsible for a different scan area, which may or may not overlap with adjacent scan areas of other exposure units. To avoid abrupt transitions from a first scan area to a second scan area adjacent to the first scan area (mounted either on the same bridge or a different bridge), the exposure unit corresponding to the first scan area may encroach into the second scan area. Similarly, the exposure unit corresponding to the second scan area may encroach into the first scan area. For example, exposure unit 1 may encroach into scan area 112-2 and / or scan area 112-3, and exposure unit 2 may encroach into scan area 112-1 and / or scan area 112-4. Thus, shared exposure may be found at the boundaries or "stitch lines" between adjacent exposure units on the same bridge and / or between exposure units on different bridges.

[0023]

[0032] The stitch lines can be defined by a clipping layer, which can be a software-defined layer that sets the boundaries of the scan path of each exposure unit during movement of the stage assembly 110. The stitch lines can be visible on the substrate after printing due to non-ideal printing conditions. For example, if the actual position of the exposure unit is moved by approximately 1 micron, a 1-micron-wide gap or double-exposed band can occur near the stitch line. Although the stitch lines in this exemplary embodiment are shown as straight lines (so that the scan area is rectangular), the stitch lines can also be curved (e.g., wavy).

[0024]

[0033] The path 130 of the exposure unit 120-1 is shown for illustrative purposes. The path 130 may proceed in a reciprocating manner. More specifically, during scanning, the stage assembly 110 moves in the X direction (i.e., from right to left) across the scan area 120-1, and during this movement, the exposure unit 120-1 patterns a line across the scan area 120-1. Upon reaching the left edge of the scan area 112-1, the stage assembly 110 moves in the Y direction (i.e., up or down) and then moves back in the X direction (i.e., from left to right) to pattern another line across the scan area 120-1. The stage assembly 110 then moves again in the Y direction (i.e., up or down) and then again in the X direction (i.e., from right to left). The path 130 may proceed in this reciprocating manner until the entire scan area 120-1 has been scanned, at which point the patterning of the full image on the substrate is complete. The image can then be developed for substrate etching. The stage travel distance "Y1" in the Y direction during scanning can be any suitable distance according to embodiments described herein. In some embodiments, Y1 can be in the range between approximately 150 mm and approximately 180 mm. For example, Y1 can be approximately 164 mm. The scan distance in the X direction of each exposure unit corresponds to the length of bridges 114-1 and 114-2 in embodiments. The overall width of the scan area "Y2" can be any suitable width according to embodiments described herein. In some embodiments, "Y2" can be in the range between approximately 1600 mm and approximately 2000 mm. For example, Y2 can be approximately 1800 mm. The travel distance (e.g., in the X direction) of each scan can vary depending on the size of the substrate. For example, in some embodiments, the substrate includes an 8-inch circular wafer. As another example, in some embodiments, the substrate includes a 12-inch circular wafer.

[0025]

[0034] 1 may be used to generate a display (e.g., a flat panel display). In some embodiments, the display is a liquid crystal display (LCD). Further details regarding scan path 130 and exposure unit 120-1 will now be described below with reference to FIGS. 2A-2D.

[0026]

[0035] 2A-2D are top-down views 200A-200D of a scanning path from the outside to the inside of a scan region 220 of a substrate through a single digital lithography exposure unit ("exposure unit") 210 of a digital lithography system, according to some embodiments. The exposure unit 210 may be, for example, exposure unit 120-1 of the digital lithography system 100 described above with reference to FIG. 1. The substrate is placed on a stage (not shown). In some embodiments, the first designated region to be scanned (e.g., a subregion of the scan region 220) may be near an edge of the scan region 220.

[0027]

[0036] 2A shows the exposure unit 210 and the scan area 220 of the substrate before the first scan is performed using the exposure unit 210. The edge 222 of the scan area 220 may be aligned with the edge 212 of the exposure unit 210 before the first scan is performed. A stage moves the substrate in the X and Y directions in accordance with a digital lithography scanning procedure to perform multiple scans across the scan area 220.

[0028]

[0037] 2B shows the formation of scanned region 230-1 in scan region 220 after a first scan is performed using exposure unit 210. More specifically, a stage moves the substrate in the positive X direction below exposure unit 210 to form scanned region 230-1. In some embodiments, scanned region 230-1 and / or scanned region 230-2 correspond to scan region 220 and a stitching region associated with an adjacent scan region. A scanned region, such as scanned region 230-1, may be referred to as a sub-region of scan region 220. The amount of time used by exposure unit 210 to scan scanned region 230-1 may be referred to as the scan duration.

[0029]

[0038] 2C shows the formation of scanned region 230-2 after a second scan is performed using exposure unit 210. More specifically, after a first scan is performed using exposure unit 210, the stage moves the substrate in the negative Y direction to align exposure unit 210 with the next designated region, and then the stage moves the substrate in the negative X direction below exposure unit 210 to form scanned region 230-2.

[0030]

[0039] 2D shows the formation of scanned region 230-3 after a third scan using exposure unit 210. More specifically, after a second scan using exposure unit 210, the stage moves the substrate in the positive Y direction to align exposure unit 210 with the next designated region, and then the stage moves the substrate in the positive X direction below exposure unit 210 to form scanned region 230-3. Additional scans, such as fourth, fifth, and sixth scans, can be performed to complete the scans by forming scanned regions 230-4, 230-5, and 230-6.

[0031]

[0040] During the scanning process described above, one or more "Mura" issues may be observed. Mura is a Japanese term that generally refers to any visible variation across a display caused by the scanning process.

[0032]

[0041] One example of mura is "scan mura," which occurs after every scan. For example, one type of scan mura is illumination non-uniformity, where the exposure area of ​​an exposure unit is not consistent. (For example, the top edge of the exposure area has a different illumination area than the bottom edge. More specifically, with each scan, such as scanning a line or "striping," the top edge of the scan will be brighter or dimmer than the bottom edge. This can adversely affect the dimensions of the patterning. Another example of mura is "vibration mura," where vibrations resulting from the operation of a digital lithography system can cause the exposure unit to vibrate, resulting in scan stuttering. The vibrations of the exposure unit may not be spatially synchronized, which can result in visible variations across the display.

[0033]

[0042] Another example of mura is "border mura," where an abrupt change in appearance can be observed at the boundary or edge between an area scanned by one exposure unit and an adjacent area scanned by another exposure unit. For example, border mura can occur at the boundary between areas scanned by adjacent pairs of exposure units of a given bridge (e.g., the boundary between scan areas 112-2 and 112-4 in FIG. 1). As another example, border mura can occur at the boundary between areas scanned by adjacent pairs of exposure units corresponding to different bridges (e.g., the boundary between scan areas 112-1 and 112-2 in FIG. 1).

[0034]

[0043] Boundary irregularities can have a number of different microscopic and / or macroscopic causes. For example, if one exposure unit emits more light than an adjacent exposure unit during a scan, abrupt changes in the line width of printed lines may be seen across the boundary between the exposure units. As another example, if one exposure unit is out of focus compared to the other exposure units, the shape of the photoresist sidewalls corresponding to each exposure unit may be different. For example, a more in-focus exposure unit may have more vertical sidewalls compared to more sloped sidewalls in a less-focused exposure unit. Thus, problems may exist at the boundary between adjacent scan areas.

[0035]

[0044] As will be described in further detail herein, mura (e.g., boundary mura) can be addressed by implementing scan sequencing as described herein (e.g., the outside-to-inside sequencing described above with reference to Figures 2A-2D or the inside-to-outside sequencing described below with reference to Figures 3A-3D) to reduce the delay between scans of stitching regions at the edges of the scan region. For example, digital lithography sequencing as described herein can be implemented to create smooth transitions between regions scanned by different exposure units (e.g., to maintain critical dimensions across the regions).

[0036]

[0045] In some embodiments, performing the sequencing described herein includes performing dose mixing, where dose refers to the amount of radiation or light to which an area is exposed. In dose mixing, the intensity of a light source may be adjusted while scanning a portion or portions of an area associated with an exposure unit. Alternatively, or in addition, different exposure levels may be provided by the exposure unit by varying the number of passes applied to various portions of an area associated with the exposure unit. For example, a first exposure unit may achieve a full dose by applying 100% of the target light intensity to most of its area. However, to a portion of its area (e.g., a stitching area), the first exposure unit may apply 50% of the target light intensity to provide a half dose. The second exposure unit may cross over into the area served by the first exposure unit (e.g., the stitching area) and apply 50% of the target light intensity to the portion of the area that received 50% of the dose by the first exposure unit. Thus, the dose or exposure from the two exposure units is effectively "mixed" in that portion of the area, so that the portion receives some dose from one exposure unit and some dose from the other exposure unit. Dose mixing can be achieved by performing a "localized multipass" at the boundary of the corresponding scan area. More specifically, multiple passes of the scan can be performed around the boundary to achieve the dose mixing effect.

[0037]

[0046] 3A-3D are top-down views 300A-300D of a scanning path from the inside to the outside of a scan region 320 of a substrate through a single digital lithography exposure unit ("exposure unit") 310 of a digital lithography system, according to some embodiments. The exposure unit 310 may be, for example, exposure unit 120-1 of the digital lithography system 100 described above with reference to FIG. 1. The substrate is placed on a stage (not shown). In some embodiments, a first designated region to be scanned (e.g., a first sub-region of the scan region 320) may be near a horizontal centerline of the scan region 320 (e.g., the centerline in the X direction).

[0038]

[0047] 3A shows the formation of scanned area 330-1 in scan area 320 after a first scan is performed using exposure unit 310. More specifically, a stage moves the substrate in the positive X direction below exposure unit 310 to form scanned area 330-1. An edge 322 of scan area 320 may be aligned with an edge 312 of exposure unit 310 before the first scan is performed. The stage moves the substrate in the X and Y directions in accordance with a digital lithography scanning procedure to perform multiple scans across scan area 320. The amount of time used by exposure unit 310 to scan scanned area 330-1 may be referred to as the scan time.

[0039]

[0048] 3B shows the formation of scanned area 330-2 after a second scan is performed using exposure unit 310. More specifically, after a first scan is performed using exposure unit 310, the stage moves the substrate in the positive Y direction to align exposure unit 310 with the next designated area, and then the stage moves the substrate in the negative X direction below exposure unit 310 to form scanned area 330-2.

[0040]

[0049] 3C shows the formation of scanned region 330-3 after a third scan using exposure unit 310. More specifically, after a second scan using exposure unit 310, the stage moves the substrate in the negative Y direction to align exposure unit 310 with the next designated region, and then the stage moves the substrate in the positive X direction below exposure unit 310 to form scanned region 330-3 below.

[0041]

[0050] 3D shows the formation of additional scanned areas 330-4, 330-5, and 330-6 after the fourth, fifth, and sixth scans are performed using exposure unit 310. More specifically, the stage shuttles the substrate in the Y direction to align exposure unit 310 with the next designated area. The stage shuttles the substrate in the X direction to form the additional scanned areas. In some embodiments, scanned areas 330-5 and 330-6 correspond to stitching areas associated with scan area 320 and adjacent scan areas.

[0042]

[0051] 4A-4C are diagrams 400A-400C illustrating examples of digital lithography exposure unit ("exposure unit") boundary smoothing, according to some embodiments. Smoothing of the exposure unit boundaries can be achieved by moving the exposure unit boundaries and / or by performing dose blending. For example, each of the diagrams 400A-400C can correspond to a clipping layer that defines the exposure unit boundaries.

[0043]

[0052] In FIG. 4A , diagram 400A shows a first scan area 410-A corresponding to a first exposure unit and a second scan area 420-A corresponding to a second exposure unit, separated by boundary 415. The first and second exposure units may be adjacent exposure units mounted on the same bridge. For example, the first exposure unit may correspond to exposure unit 1 in FIG. 1, and the second exposure unit may correspond to exposure unit 2 in FIG. 1. Alternatively, the first and second exposure units may be adjacent exposure units mounted on different bridges. For example, the first exposure unit may correspond to exposure unit 1 in FIG. 1, and the second exposure unit may correspond to exposure unit 12 in FIG. 1.

[0044]

[0053] In this example, there is no exposure unit boundary smoothing between the first scan area 410-A and the second scan area 420-A. More specifically, the first exposure unit is 100% responsible for scanning up to boundary 415 within the first scan area 410-A, and then the second exposure unit is 100% responsible for scanning up to boundary 415 within the second scan area 420-A. In other words, the first scan area 410-A receives 100% of the dose from the first exposure unit, and the second scan area 420-A receives 100% of the dose from the second exposure unit.

[0045]

[0054] In FIG. 4B, diagram 400B shows a first scan area 410-B corresponding to a first exposure unit and a second scan area 420-B corresponding to a second exposure unit. Here, sawtooth blending occurs as a result of smoothing the exposure unit boundary between the first scan area 410-B and the second scan area 420-B. More specifically, the first exposure unit is programmed to extend within the original scan area corresponding to the second exposure unit (e.g., scan area 410-B in FIG. 4A), and the second exposure unit is programmed to extend within the original scan area corresponding to the first exposure unit (e.g., scan area 410-A in FIG. 4A). The sawtooth blending is illustrated in FIG. 4B by vertical boundaries 430-1 through 430-4 and horizontal boundaries 435-1 through 435-3. Boundaries 430-1 through 430-4 and 435-1 through 435-3 may not be visible and are provided to illustrate the smoothing of the exposure unit boundaries shown in FIG. 3B. A mixed dose region is defined between vertical boundary 430-1 and vertical boundary 430-4. In relation to the region defined by horizontal boundary 435-1, the first exposure unit provides a 75% dose and the second exposure unit provides a 25% dose. In relation to the region defined by horizontal boundary 435-2, both the first and second exposure units provide a 50% dose. In relation to the region defined by horizontal boundary 435-3, the first exposure unit provides a 25% dose and the second exposure unit provides a 75% dose.

[0046]

[0055] The boundary smoothing in FIG. 4B is achieved by exposure unit boundary movement and / or dose blending. For exposure unit boundary movement, multiple passes are performed to achieve sawtooth blending. In this exemplary embodiment, four passes may be performed, with the exposure unit boundaries moved after each pass (i.e., four-pass boundary movement). For example, in the case of one bridge, the exposure unit boundaries may be moved vertically (e.g., by vertically moving the clipping layer), and in the case of two bridges, the exposure unit boundaries may be moved horizontally (e.g., by horizontally moving the clipping layer). For dose blending, a single pass is performed, but "local passes" may be made around the original boundary 415 to provide a specified amount of dose for each of the exposure units. In this exemplary embodiment, the first and second exposure units may each provide four amounts of dose (100%, 75%, 50%, and 25%) to achieve the exposure unit boundary smoothing shown in FIG. 4B.

[0047]

[0056] In FIG. 4C , diagram 400C shows a first exposure unit region 410-C and a second exposure unit region 420-C with gradual blending corresponding to a diagonal boundary 440. In some embodiments, the horizontal distance covered by boundary 440 corresponds to the stitching region between the first exposure unit region 410-C and the second exposure unit region 420-C. The gradual blending to achieve diagonal boundary 440 is a theoretical ideal for smoothing the boundaries in the stitching region. This ideal can be achieved through an appropriate number of (e.g., infinite) passes during exposure unit boundary movement and / or through an appropriately fine (e.g., infinitely fine) dose blending around each exposure unit boundary during dose blending.

[0048]

[0057] 5 is a diagram 500 of an exemplary scan structure 520 of a digital lithography exposure unit in a one-bridge configuration, according to some embodiments. The scan structure 520 illustrates an exemplary stitching region 524 associated with a first scan region 521 and a second scan region 522. In some embodiments, the stitching region 524 is at the boundary between the first scan region 521 and the second scan region 522. For example, the first scan region 521 may be associated with a first exposure unit, and the second scan region 522 may be associated with a second exposure unit. The boundaries of both the first and second exposure units may overlap, and the overlapping region may correspond to the stitching region 524.

[0049]

[0058] In some embodiments, a first exposure unit scans the stitching region 524, and a second exposure unit scans a sub-region of the second scan region 522. Subsequently, the second exposure unit scans the stitching region, and the first exposure unit scans a sub-region of the first scan region. In some embodiments, the first and second exposure units each scan the stitching region 524 using a partial dose, so that over two scans, the stitching region 524 receives a full dose. For example, the first exposure unit may scan the stitching region 524 with a 50% dose, followed by the second exposure unit scanning the stitching region 524 with an additional 50%. In some embodiments, one or more of the boundary smoothing techniques described with reference to FIGS. 4A-4C are performed on the stitching region 524 by the first and second exposure units. In some embodiments, as described below with reference to FIGS. 6A-6B, a second scan of the stitching region 524 is performed following the first scan of the stitching region 524 within a threshold duration.

[0050]

[0059] 6A and 6B are diagrams of exemplary scan sequences of a digital lithography exposure unit with respect to time, according to some embodiments. Figure 6A is a diagram of an outside-to-inside scan sequence 600A of a digital lithography exposure unit with respect to time, according to some embodiments. Figure 6B is a diagram of an inside-to-outside scan sequence 600B of a digital lithography exposure unit with respect to time, according to some embodiments.

[0051]

[0060] In some embodiments, the stitching area 624 is associated with the first scan area 621 and the second scan area 622. The stitching area 624 may correspond to a boundary area between the first scan area 621 and the second scan area 622. In some embodiments, a first exposure unit of a digital lithography system may have a boundary area that includes the first scan area 621 and the stitching area 624. A second exposure unit may have a boundary area that includes the second scan area 622 and the stitching area 624. The first and second exposure units may be attached to the same bridge unit. Thus, the first and second exposure units may move together relative to the substrate (i.e., the first scan area 621, the second scan area 622, and the stitching area 624).

[0052]

[0061] Referring to FIG. 6A , an outside-to-inside scan sequence 600A is shown. For purposes of illustration and description, the outside-to-inside scan sequence 600A includes four distinct time intervals during a scan operation. However, the number of distinct time intervals in the sequence 600A is not limited to four. In some embodiments, the outside-to-inside scan sequence 600A includes more distinct time intervals during a scan operation. In some embodiments, for the duration of time interval 612-1, a first exposure unit (not shown) scans a first sub-region 614-1A of a first scan region 621. Similarly, a second exposure unit (not shown) scans a first sub-region 614-1B of a second scan region 622, which corresponds to a stitching region 624. In some embodiments, the second exposure unit scans the first sub-region 614-1B, which corresponds to a stitching region 624, with a partial radiation dose. The first exposure unit may scan the first sub-region 614-1A with the full dose of radiation. Sub-regions 614-1A and 614-1B may be "outer" sub-regions. In some embodiments, the first sub-region 614-1A is adjacent to the outer edge of the first scan region 621. Due to the nature of the stitching region 624 located at the boundary between the first scan region 621 and the second scan region 622, the sub-region 614-1B is adjacent to the outer edge of the second scan region 622. After the time interval 612-1 ends, the stage carrying the substrate moves in the Y direction to align with the first and second exposure units, and the next sub-region is scanned.

[0053]

[0062] Over the duration of time interval 612-2, the first exposure unit scans a second sub-region 614-2A of first scan region 621, and the second exposure unit scans a second sub-region 614-2B of second scan region 622. In some embodiments, the first exposure unit scans second sub-region 614-2A, which corresponds to stitching region 624, with a partial dose of radiation. The second exposure unit may scan second sub-region 614-2B with a full dose of radiation. In some embodiments, second sub-region 614-2A is located near an outer edge of first scan region 621, and second sub-region 614-2B is located near an outer edge of second scan region 622. In some embodiments, the second subregions 614-2A and 614-2B are located near the opposite end of the corresponding first subregions 614-1A and 614-1B. The subregions 614-2A and 614-2B may be "outer" subregions. After the time interval 612-2 ends, the stage moves in the Y direction to align with the first and second exposure units, and the next subregion is scanned.

[0054]

[0063] Over the duration of time interval 612-3, the first exposure unit scans a third sub-region 614-3A of the first scan region 621, and the second exposure unit scans a third sub-region 614-3B of the second scan region 622. The third sub-region 614-3A may be proximate to the first sub-region 614-1A, and the third sub-region 614-3B may be proximate to the first sub-region 614-1B. The third sub-region 614-3A may be closer to the horizontal centerline of the first scan region 621 than the first sub-region 614-1A, and the third sub-region 614-3B may be closer to the horizontal centerline of the second scan region 622 than the first sub-region 614-1B. In some embodiments, the third sub-regions 614-3A and 614-3B are “inner” sub-regions. After time interval 612-3 ends, the stage moves in the Y direction to align with the first and second exposure units and the next sub-region is scanned.

[0055]

[0064] Over the duration of time interval 612-4, the first exposure unit scans a fourth sub-region 614-4A of the first scan region 621, and the second exposure unit scans a fourth sub-region 614-4B of the second scan region 622. The fourth sub-region 614-4A may be proximate to the second sub-region 614-2A, and the fourth sub-region 614-4B may be proximate to the second sub-region 614-2B. The fourth sub-region 614-4A may be closer to the horizontal centerline of the first scan region 621 than the second sub-region 614-2A, and the fourth sub-region 614-4B may be closer to the horizontal centerline of the second scan region 622 than the second sub-region 614-2B. In some embodiments, the fourth sub-regions 614-4A and 614-4B are “inner” sub-regions. In some embodiments, according to scan sequence 600A, the outer sub-regions are scanned before the inner sub-regions. After time interval 612-4 is over, first scan region 621 and second scan region 622 may all be scanned, which may form one or more scan features generated by scanning. Each of time intervals 612-1, 612-2, 612-3, and / or 612-4 may be a scan time.

[0056]

[0065] Referring to FIG. 6B, an inside-to-outside scan sequence is shown. For purposes of illustration and description, inside-to-outside scan sequence 600B includes four distinct time intervals during the scan operation. However, the number of time intervals in sequence 600B is not limited to four. In some embodiments, inside-to-outside scan sequence 600B includes more distinct time intervals during the scan operation. In some embodiments, for the duration of time interval 612-1, a first exposure unit scans a first sub-area 614-1A of a first scan area 621, and a second exposure unit scans a first sub-area 614-1B of a second scan area 622. The first sub-areas 614-1A and 614-1B may be "inner" sub-areas of the first scan area 621 and the second scan area 622, respectively. In some embodiments, the first sub-region 614-1A is near the horizontal centerline of the first scan region 621, and the first sub-region 614-1B is near the horizontal centerline of the second scan region 622. After the time interval 612-1 ends, the stage moves in the Y direction to align with the first and second exposure units, and the next sub-region is scanned.

[0057]

[0066] In some embodiments, over the duration of time interval 612-2, the first exposure unit scans a second sub-region 614-2A of the first scan region 621, and the second exposure unit scans a second sub-region 614-2B of the second scan region 622. The second sub-regions 614-2A and 614-2B may be "inner" sub-regions of the first scan region 621 and the second scan region 622, respectively. In some embodiments, the second sub-region 614-2A is near the horizontal centerline of the first scan region 621 and is on the opposite side of the centerline from the first sub-region 614-1A. In some embodiments, the second sub-region 614-2B is near the horizontal centerline of the second scan region 622 and is on the opposite side of the centerline from the first sub-region 614-1B. After time interval 612-2 ends, the stage moves in the Y direction to align with the first and second exposure units and the next sub-region is scanned.

[0058]

[0067] In some embodiments, over the duration of time interval 612-3, the first exposure unit scans a third sub-region 614-3A of the first scan region 621, and the second exposure unit scans a third sub-region 614-3B of the second scan region 622. The third sub-regions 614-3A and 614-3B may be "outer" sub-regions of the first scan region 621 and the second scan region 622, respectively. In some embodiments, the third sub-region 614-3A is adjacent to the outer edge of the first scan region 621. The third sub-region 614-3A may correspond to the stitching region 624. In some embodiments, the third sub-region 614-3B is adjacent to the outer edge of the second scan region 622. In some embodiments, the first exposure unit may scan a third sub-region 614-3A, corresponding to stitching region 624, with a partial dose of radiation. The second exposure unit may scan a third sub-region 614-3B with a full dose of radiation. After time interval 612-3 ends, the stage moves in the Y direction to align with the first and second exposure units, and the next sub-region is scanned.

[0059]

[0068] In some embodiments, over the duration of time interval 612-4, the first exposure unit scans a fourth sub-region 614-4A of the first scan region 621, and the second exposure unit scans a fourth sub-region 614-4B of the second scan region 622. The fourth sub-regions 614-4A and 614-4B may be “outer” sub-regions of the first scan region 621 and the second scan region 622, respectively. In some embodiments, according to scan sequence 600B, the inner sub-regions are scanned before the outer sub-regions. After time interval 612-4 ends, all of the first scan region 621 and the second scan region 622 may have been scanned, and one or more scan features may be generated by scanning.

[0060]

[0069] In some embodiments, each of the time intervals 612-1, 612-2, 612-3, and 612-4 has a predetermined length of time. In some embodiments, each time interval has a duration of less than 40 seconds. In some embodiments, each time interval has a duration of 1 to 20 seconds. In some embodiments, each time interval has a duration of approximately 3 seconds. In some embodiments, each time interval has a duration of approximately 8 seconds. In some embodiments, the scanning operations performed on the stitching region 624 (e.g., a first scan performed by a first exposure unit and a second scan performed by a second exposure unit) are performed at times that are separated by less than 40 seconds. In some embodiments, the scanning operations performed on the stitching region 624 are performed at times that are separated by less than 1 to 20 seconds. In some embodiments, the scanning operations performed on the stitching region 624 are performed at times that are separated by less than 8 seconds. In some embodiments, the scanning operations performed on the stitching region 624 are performed at times that are separated by less than 3 seconds.

[0061]

[0070] FIG. 7 illustrates a feature formed on a substrate by a digital lithography process, according to some embodiments. Diagram 700A illustrates a scanned feature formed on a substrate using a scan sequence that creates a large time delay between the first and second scans over a stitching region 724. Diagram 700B illustrates a scanned feature formed on a substrate using a digital lithography scan sequence described herein that creates a time delay between the first and second scans over the stitching region 724 that is less than a threshold required time. As illustrated by Diagram 700A, performing a scan operation over the stitching region 724 with a delay greater than the threshold required time can result in an anomaly 726 being formed in the feature by the scan. Such an anomaly 726 can include defects that require the scanned substrate to be discarded. As shown by FIG. 700B, when scan operations are performed on the stitching region 724 with a delay shorter than the threshold required time, anomalies due to the delay between scans may not occur. In some embodiments, the threshold required time is about 40 seconds. In some embodiments, the threshold required time is about 20 seconds. In some embodiments, the threshold required time is about 8 seconds. In some embodiments, the threshold required time is about 3 seconds. The delay between scanning the stitching region at a first time using a first exposure unit and scanning the stitching region at a second time using a second exposure unit may be reduced by using an inside-to-outside scan sequence or an outside-to-inside scan sequence for the first scan region 721 and the second scan region 722. Reducing the delay between scans performed on the stitching region 724 reduces defects formed on the substrate, thereby improving process performance.

[0062]

[0071] FIG. 8 illustrates a flow diagram of a method 800 for implementing digital lithography scan sequencing, according to some embodiments. The method may be performed by processing logic, which may include hardware (circuitry, dedicated logic, etc.), computer-readable instructions (instructions executed on a general-purpose computer system or a dedicated machine), or a combination of both. In an exemplary embodiment, method 800 may be performed by a processing device of a digital lithography system. Note that the blocks shown in FIG. 8 may be performed simultaneously or in a different order than shown.

[0063]

[0072] At block 810, processing logic receives instructions to perform a digital photolithography process to pattern a substrate. At block 820, processing logic initiates the digital lithography process to pattern the substrate in accordance with the instructions. In accordance with the instructions, the substrate is placed on a stage, and the stage may move in the X and Y directions below a digital lithography exposure unit ("exposure unit"). For example, the instructions may be executed to implement the scan sequencing described earlier in this specification. In some embodiments, the digital lithography process is a multiple pass process that includes multiple passes to scan two or more adjacent scan areas.

[0064]

[0073] At block 830, processing logic performs a first pass of a first exposure unit at a first time on the stitching region. The stitching region may be at the boundary between a first scan region corresponding to the first exposure unit and a second scan region corresponding to the second exposure unit. In some embodiments, the first exposure unit provides a partial dose of radiation to the stitching region. For example, the first exposure unit may provide 50% of the total dose of radiation to the stitching region during the first pass. While the first exposure unit performs its first pass on the stitching region, the second exposure unit may perform a pass on a sub-region of the second scan region associated with the second exposure unit.

[0065]

[0074] At block 840, processing logic performs a second pass of the second exposure unit on the stitching region at a second time. In some embodiments, the second time differs from the first time by less than about 40 seconds. In some embodiments, the second time differs from the first time by less than about 20 seconds, less than about 8 seconds, or less than about 3 seconds. In some embodiments, the second exposure unit delivers a partial radiation dose to the stitching region. For example, the second exposure unit may deliver 50% of the total radiation dose to the stitching region during the first pass. In some embodiments, the first exposure unit delivers a first percentage of radiation to the stitching region during the first pass, and the second exposure unit delivers a second percentage of radiation to the stitching region during the second pass. The sum of the first percentage and the second percentage equals 100%. While the second exposure unit performs a second pass over the stitching region, the first exposure unit may perform a pass over a sub-region of the first scan region associated with the first exposure unit.

[0066]

[0075] In some embodiments, the first pass and / or the second pass are performed at the beginning or end of a multiple pass digital lithography process. In some embodiments, the processing logic uses an outside-to-inside scanning sequence as described herein with reference to FIG. 6A or an inside-to-outside scanning sequence as described herein with reference to FIG. 6B. In some embodiments, a second pass of the second exposure unit over the stitching region follows a first pass of the first exposure unit over the stitching region.

[0067]

[0076] 9 is a block diagram illustrating a digital lithography system (“system”) 900, in accordance with some embodiments. As shown, system 900 includes a digital lithography exposure unit (“exposure unit”) 910, a stage 920, and a processing device 930. Processing device 930 includes a processor 932 operably coupled to memory 934. The memory may hold instructions 936 for performing digital lithography in system 900. For example, instructions 936 may include instructions for controlling movement of stage 920 and / or exposure unit 910. The instructions, when executed, may implement the method for performing exposure unit scan sequencing described herein above.

[0068]

[0077] FIG. 10 is a block diagram illustrating a computer system 1000, according to certain embodiments. In some embodiments, computer system 1000 is connected to other computer systems (e.g., via a network such as a local area network (LAN), an intranet, an extranet, or the Internet). In some embodiments, computer system 1000 operates in the capacity of a server or a client computer in a client-server environment, or as a peer computer in a peer-to-peer or distributed network environment. In some embodiments, computer system 1000 is provided by a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile phone, a web appliance, a server, a network router, switch, or bridge, or any device capable of executing a set of instructions (sequential or otherwise) that specify operations to be performed by that device. Furthermore, the term "computer" is intended to include any collection of computers that individually or collectively execute a set (or sets) of instructions to perform any one or more of the methodologies described herein.

[0069]

[0078] In a further aspect, computer system 1000 includes a processing device 1002, a volatile memory 1004 (e.g., random access memory (RAM)), a non-volatile memory 1006 (e.g., read-only memory (ROM) or electrically erasable programmable ROM (EEPROM)), and a data storage device 1018, which communicate with each other via a bus 1008.

[0070]

[0079] In some embodiments, the processing device 1002 is provided by one or more processors, such as a general-purpose processor (e.g., a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a microprocessor implementing another type of instruction set, or a microprocessor implementing a combination of instruction set types), or a special-purpose processor (e.g., an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a digital signal processor (DSP), or a network processor, etc.).

[0071]

[0080] In some embodiments, computer system 1000 further includes a network interface device 1022 (e.g., connected to network 1074). In some embodiments, computer system 1000 also includes a video display unit 1010 (e.g., LCD), an alphanumeric input device 1012 (e.g., keyboard), a cursor control device 1014 (e.g., mouse), and a signal generating device 1020.

[0072]

[0081] In some embodiments, the data storage device 1018 includes a non-transitory computer-readable storage medium 1024 having stored thereon instructions 1026 encoding any one or more of the methods or functions described herein. For example, the instructions 1026 may include instructions for controlling movement of a stage and / or a digital lithography exposure unit ("exposure unit") of a digital lithography system, which, when executed, may implement a method for performing exposure unit scan sequencing described herein.

[0073]

[0082] In some embodiments, the instructions 1026 also reside, completely or partially, within the volatile memory 1004 and / or within the processing device 1002 during execution by the computer system 1000; therefore, in some embodiments, the volatile memory 1004 and the processing device 1002 also constitute machine-readable storage media.

[0074]

[0083] Although computer-readable storage medium 1024 is illustrated as a single medium in the exemplary embodiment, the term "computer-readable storage medium" is intended to include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) that store one or more sets of executable instructions. The term "computer-readable storage medium" is also intended to include any tangible medium that is capable of storing or encoding a set of instructions that are executed by a computer to cause the computer to perform any one or more of the methods described herein. The term "computer-readable storage medium" includes, but is not limited to, solid-state memory, optical media, and magnetic media.

[0075]

[0084] In some embodiments, the methods, components, and features described herein are implemented by discrete hardware components or integrated into the functionality of other hardware components, such as an ASIC, FPGA, DSP, or similar device. In some embodiments, the methods, components, and features are implemented by firmware modules or functional circuitry within a hardware device. In some embodiments, the methods, components, and features are implemented in any combination of hardware devices and computer program components, or in a computer program.

[0076]

[0085] Unless otherwise specified, terms such as "training," "identifying," "further training," "retraining," "causing," "receiving," "providing," "taking," "optimizing," "determining," "updating," "initiating," "generating," "adding," and the like refer to operations or processes performed or implemented by a computer system. These processes manipulate and transform data represented as physical (electronic) quantities in the computer system's registers and memory into other data that are likewise represented as physical quantities in the computer system's memory or registers, or other such information storage, transmission, or display device. In some embodiments, the terms "first," "second," "third," "fourth," and the like, as used herein, are intended as distinguishing labels between different elements, and no hierarchy according to their numerical designations is implied.

[0077]

[0086] The embodiments described herein also relate to apparatus for performing the methods described herein. In some embodiments, the apparatus comprises a general-purpose computer system that is specially configured to perform the methods described herein, or that is selectively programmed by a computer program stored on the computer system. Such a computer program is stored on a computer-readable tangible storage medium.

[0078]

[0087] The methods and illustrative examples described herein are not inherently related to any particular computer or other apparatus. In some embodiments, various general-purpose systems are used in accordance with the teachings described herein. In some embodiments, more specialized apparatus are constructed to perform the methods described herein and / or each of their individual functions, routines, subroutines, or steps. Example structures for these various systems are set forth in the description above.

[0079]

[0088] The foregoing description sets forth numerous specific details, such as examples of specific systems, components, methods, etc., to provide a thorough understanding of some embodiments of the present invention. However, it will be apparent to those skilled in the art that at least some embodiments of the present invention may be practiced without these specific details. In other instances, well-known components or methods are not described in detail or are presented in simple block diagram form to avoid unnecessarily obscuring the present invention. Thus, the specific details shown are merely exemplary. Particular implementations can vary from these example details and still be considered within the scope of the present invention.

[0080]

[0089] Throughout this document, references to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment. Thus, appearances of the phrase "in one embodiment" or "in an embodiment" in various places throughout this document are not necessarily all referring to the same embodiment. Additionally, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or." When the term "about" or "approximately" is used herein, it is intended to mean that the stated nominal value is accurate to within ±10%.

[0081]

[0090] Although the operations of the methods herein are illustrated and described in a particular order, the order of the operations of each method may be changed so that certain operations may be performed in the reverse order or so that certain operations may be performed at least in part concurrently with other operations. In alternative embodiments, instructions or sub-operations of individual operations may be performed intermittently and / or alternately.

[0082]

[0091] It should be understood that the above description is intended to be illustrative, and not limiting. Many other exemplary embodiments will become apparent to those skilled in the art upon reading and understanding the above description. While the present disclosure describes particular embodiments, it should be recognized that the systems and methods of the present disclosure are not limited to the embodiments described herein, but may be practiced with modification within the scope of the appended claims. Accordingly, the specification and drawings should be regarded in an illustrative rather than a restrictive sense. The scope of the present disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. a plurality of scan areas including a first scan area and a second scan area adjacent to the first scan area; a plurality of exposure units positioned above the plurality of scan areas, the plurality of exposure units including a first exposure unit associated with the first scan area and a second exposure unit associated with the second scan area; Memory, and at least one processing device operably coupled to the memory, initiating a digital lithography process to pattern a substrate disposed on the stage according to the instructions; performing a first pass of the first exposure unit at a first time on a stitching area at the boundary between the first scan area and the second scan area; and performing a second pass of the second exposure unit over the stitching area at a second time that differs from the first time by less than 40 seconds; at least one processing device for performing A digital lithography system comprising:

2. the digital lithography process is a multiple pass process including multiple passes, and performing the digital lithography process includes performing the first pass followed by the second pass at the beginning of the multiple pass process or at the end of the multiple pass process. The digital lithography system of claim 1 .

3. the first exposure unit and the second exposure unit are mounted on the same bridge of the digital lithography system; To perform the digital lithography process, the at least one processing device: scanning a first sub-area of ​​the second scan area using the second exposure unit while performing the first pass using the first exposure unit; scanning a second sub-area of ​​the first scan area using the first exposure unit while performing the second pass using the first exposure unit; The digital lithography system of claim 1 , further comprising:

4. The digital lithography process comprises: scanning a first sub-area of ​​each of the plurality of scan areas near a first end of the scan area; Subsequently, scanning a second sub-region of each of the scan areas near a second end of each of the scan areas opposite the first end, wherein the first sub-region or the second sub-region includes the stitching region; and subsequently scanning a third sub-region of each scan region adjacent to the first sub-region opposite the first end; The digital lithography system of claim 1 , comprising:

5. The digital lithography process comprises: scanning a first sub-area of ​​each of the plurality of scan areas adjacent to a centerline of each of the scan areas; subsequently scanning a second sub-area of ​​each of the scan areas adjacent to the first sub-area toward a first end of each of the scan areas; scanning a third sub-area of ​​each of the scan areas near the first end or the second end of each of the scan areas; and Subsequently, scanning a fourth sub-region of each of the scan areas near the first end or the second end opposite to the third sub-region, wherein the third sub-region or the fourth sub-region includes the stitching region; The digital lithography system of claim 1 , comprising:

6. performing the first pass and performing the second pass includes performing dose mixing on the stitching region, wherein performing dose mixing includes causing the first exposure unit to provide a first percentage of a total dose on the stitching region and causing the second exposure unit to provide a second percentage of the total dose on the stitching region, wherein a sum of the first percentage and the second percentage equals 100%. The digital lithography system of claim 1 .

7. the second time period differs from the first time period by approximately one scan time period; The digital lithography system of claim 1 .

8. Memory, and at least one processing device operably coupled to the memory, initiating a digital lithography process to pattern the substrate according to the instructions; performing a first pass of a first exposure unit at a first time on a stitching area at a boundary between a first scan area of ​​the plurality of scan areas and a second scan area of ​​the plurality of scan areas; and performing a second pass of a second exposure unit over the stitching area at a second time that differs from the first time by less than 40 seconds; at least one processing device for performing A system comprising:

9. 9. The system of claim 8, wherein the digital lithography process is a multiple pass process including multiple passes, and performing the digital lithography process includes performing the first pass followed by the second pass at the beginning of the multiple pass process or at the end of the multiple pass process.

10. the first exposure unit and the second exposure unit are mounted on the same bridge of the system; To perform the digital lithography process, the at least one processing device: scanning a first sub-area of ​​the second scan area using the second exposure unit while performing the first pass using the first exposure unit; scanning a second sub-area of ​​the first scan area using the first exposure unit while performing the second pass using the first exposure unit; The system of claim 8 , further comprising:

11. The digital lithography process comprises: scanning a first sub-area of ​​each of the plurality of scan areas near a first end of the scan area; Subsequently, scanning a second sub-region of each of the scan areas near a second end of each of the scan areas opposite the first end, wherein the first sub-region or the second sub-region includes the stitching region; and subsequently scanning a third sub-region of each scan region adjacent to the first sub-region opposite the first end; The system of claim 8 , comprising:

12. The digital lithography process comprises: scanning a first sub-area of ​​each of the plurality of scan areas adjacent to a centerline of each of the scan areas; subsequently scanning a second sub-area of ​​each of the scan areas adjacent to the first sub-area toward a first end of each of the scan areas; scanning a third sub-area of ​​each of the scan areas near the first end or the second end of each of the scan areas; and Subsequently, scanning a fourth sub-region of each of the scan areas near the first end or the second end opposite to the third sub-region, wherein the third sub-region or the fourth sub-region includes the stitching region; The system of claim 8 , comprising:

13. performing the first pass and performing the second pass includes performing dose mixing on the stitching region, wherein performing dose mixing includes causing the first exposure unit to provide a first percentage of a total dose on the stitching region and causing the second exposure unit to provide a second percentage of the total dose on the stitching region, wherein a sum of the first percentage and the second percentage equals 100%. The system of claim 8.

14. the second time period differs from the first time period by less than 8 seconds; The system of claim 8.

15. 1. A method comprising: initiating, by a processing device, a digital lithography process to pattern the substrate according to the instructions; performing a first pass of a first exposure unit at a first time on a stitching area at a boundary between a first scan area of ​​the plurality of scan areas and a second scan area of ​​the plurality of scan areas; and performing a second pass of a second exposure unit over the stitching area at a second time that differs from the first time by less than 40 seconds; A method comprising:

16. the digital lithography process is a multiple pass process including multiple passes, and performing the digital lithography process includes performing the first pass followed by the second pass at the beginning of the multiple pass process or at the end of the multiple pass process.

16. The method of claim 15.

17. the first exposure unit and the second exposure unit are mounted on the same bridge of a digital lithography system; The digital lithography process comprises: scanning a first sub-area of ​​the second scan area with the second exposure unit while performing the first pass with the first exposure unit; and scanning a second sub-area of ​​the first scan area with the first exposure unit while performing the second pass with the first exposure unit; 16. The method of claim 15, comprising:

18. The digital lithography process comprises: scanning a first sub-area of ​​each of the plurality of scan areas near a first end of the scan area; Subsequently, scanning a second sub-region of each of the scan areas near a second end of each of the scan areas opposite the first end, wherein the first sub-region or the second sub-region includes the stitching region; and subsequently scanning a third sub-region of each scan region adjacent to the first sub-region opposite the first end; 16. The method of claim 15, comprising:

19. The digital lithography process comprises: scanning a first sub-area of ​​each of the plurality of scan areas adjacent to a centerline of each of the scan areas; subsequently scanning a second sub-area of ​​each of the scan areas adjacent to the first sub-area toward a first end of each of the scan areas; scanning a third sub-area of ​​each of the scan areas near the first end or the second end of each of the scan areas; and Subsequently, scanning a fourth sub-region of each of the scan areas near the first end or the second end opposite to the third sub-region, wherein the third sub-region or the fourth sub-region includes the stitching region; 16. The method of claim 15, comprising:

20. performing the first pass and performing the second pass includes performing dose mixing on the stitching region, wherein performing dose mixing includes causing the first exposure unit to provide a first percentage of a total dose on the stitching region and causing the second exposure unit to provide a second percentage of the total dose on the stitching region, wherein a sum of the first percentage and the second percentage equals 100%.

16. The method of claim 15.

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