Grating exposure system and method

Abstract

The invention discloses a grating exposure system and method, and relates to the field of optics, and the grating exposure system comprises a movable motion platform which is used for bearing a substrate and driving the substrate to move, so that a to-be-prepared grating structure is formed on the substrate, and the to-be-prepared grating structure is formed by splicing a plurality of grating partitions; the light source module is used for outputting light beams; the light beam adjusting module is used for adjusting the light beam to form a light spot in a target shape; the exposure module is used for forming an exposure field with a target shape on a substrate by utilizing the adjusted light beam so as to form a grating partition; and the control module is used for controlling the motion platform to drive the substrate to rotate according to a target exposure strategy, so that the exposure field of the target shape generated after rotation coincides with the exposure field of the target shape generated before rotation. Therefore, a regular and beautiful densely paved grating structure with macroscopic abutted seams can be obtained, and the exposure preparation of the polygonal abutted seam grating with low cost, low implementation difficulty and high efficiency is realized.

Description

Technical Field

[0001] This application relates to the field of optical technology, and more specifically, to a grating exposure system and method. Background Art

[0002] In technologies for efficiently fabricating periodic micro-nano structures such as interference lithography (holographic lithography) and Talbot lithography, multiple small exposure fields are usually stitched together to fabricate a large-area grating. Limited by the imaging characteristics of the exposure field or the stitching displacement accuracy of the exposure fields, there are often macroscopically visible seams between the exposure fields. The shape of a single exposure area directly affects the appearance of the large-area grating.

[0003] In addition, in holographic and interference exposure methods, two-dimensional gratings are often fabricated by means of secondary exposure after rotating the substrate. The secondary stitching exposure after substrate rotation causes two sets of macro seams to overlap at an angle, thereby forming a more complex macro seam pattern, and further generating more obvious stray light, resulting in an irregular and unaesthetic grating structure. Summary of the Invention

[0004] In view of the above problems, this application proposes a grating exposure system and method.

[0005] In a first aspect, an embodiment of this application provides a grating exposure system, where the grating exposure system includes: a movable stage for carrying a substrate and driving the substrate to move so as to form a grating structure to be fabricated on the substrate, and the grating structure to be fabricated is composed of a plurality of grating partitions stitched together; a light source module for outputting a light beam; a beam adjustment module for adjusting the light beam to form a light spot with a target shape; an exposure module for using the adjusted light beam to form an exposure field with the target shape on the substrate to form the grating partition; and a control module for controlling the stage to drive the substrate to rotate according to a target exposure strategy so that the exposure field with the target shape generated after rotation coincides with the exposure field with the target shape generated before rotation.

[0006] In a second aspect, an embodiment of this application further provides a grating exposure method applied to the foregoing grating exposure system, and the method includes: outputting a light beam through the light source module; adjusting the light beam through the beam adjustment module to form a light spot with a target shape; using the adjusted light beam through the exposure module to form an exposure field with the target shape on the substrate to form a grating partition in the grating structure to be fabricated; and controlling, by the control module according to a target exposure strategy, the movable stage to drive the carried substrate to rotate so that the exposure field with the target shape generated after rotation coincides with the exposure field with the target shape generated before rotation.

[0007] The grating exposure system provided by the present application includes a movable stage in the grating exposure system, which is used to carry a substrate and drive the substrate to move so as to form a grating structure to be prepared on the substrate. The grating structure to be prepared is composed of a plurality of grating partitions spliced together; a light source module, which is used to output a light beam; a light beam adjustment module, which is used to adjust the light beam to form a light spot with a target shape; an exposure module, which is used to use the adjusted light beam to form an exposure field with a target shape on the substrate to form a grating partition; a control module, which is used to control the stage to drive the substrate to rotate according to a target exposure strategy so that the exposure field with the target shape generated after rotation coincides with the exposure field with the target shape generated before rotation. Thereby, the generation of stray light is reduced, and finally a densely paved grating structure with regular and beautiful macroscopic seams can be obtained, realizing the exposure preparation of a polygon-seamed grating with low cost, low implementation difficulty and high efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0009] Figure 1 FIG. 1 shows a system architecture diagram of a grating exposure system provided by an embodiment of the present application;

[0010] Figure 2 FIG. 2 shows a schematic distribution diagram of sub-partitions in a grating structure provided by an embodiment of the present application;

[0011] Figure 3 FIG. 3 shows a schematic distribution diagram of sub-partitions in another grating structure provided by an embodiment of the present application;

[0012] Figure 4 FIG. 4 shows a schematic distribution diagram of sub-partitions in still another grating structure provided by an embodiment of the present application;

[0013] Figure 5 FIG. 5 shows a schematic distribution diagram of sub-partitions in yet another grating structure provided by an embodiment of the present application;

[0014] Figure 6 FIG. 6 shows a schematic distribution diagram of sub-partitions in still yet another grating structure provided by an embodiment of the present application;

[0015] Figure 7 FIG. 7 shows a schematic diagram of the seam between adjacent sub-partitions in the grating structure provided by an embodiment of the present application;

[0016] Figure 8Shows a system architecture diagram of a grating exposure system provided by another embodiment of the present application;

[0017] Figure 9 Shows a process schematic diagram of the preparation of a grating structure provided by an embodiment of the present application;

[0018] Figure 10 Shows a system architecture diagram of a grating exposure system provided by yet another embodiment of the present application;

[0019] Figure 11 Shows a method flowchart of a grating exposure method provided by an embodiment of the present application. Detailed implementation manners

[0020] In order to enable those skilled in the art to better understand the solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application.

[0021] In the description of the present invention, terms such as "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more, unless otherwise specifically defined.

[0022] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication with each other; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0023] Large-area gratings have very important applications in many technical fields, such as large-size optical waveguides in augmented reality head-up display systems, large-aperture astronomical telescopes, high-power chirped pulse amplification systems for inertial confinement fusion, precision interferometric measurements, etc. The mainstream methods for preparing large-area gratings include mechanical scribing, electron beam direct writing, and interference lithography. Among them, due to the parallel exposure principle of the optical interference effect, interference lithography has the advantages of high efficiency, low cost, and high precision, and is the mainstream method for preparing large-area gratings.

[0024] There are two technical routes for fabricating large-area gratings by interference exposure: single large-area exposure method and stitching exposure method. Among them, the single large-area exposure method places extremely high requirements on the aberration of large-aperture optical lenses, and the processing of large-aperture lenses required is extremely difficult and costly. In addition, the single exposure method limits the degree of freedom in the design of gratings within a large area and cannot fabricate more diverse large-area gratings.

[0025] In related technologies, the stitching exposure method generally has stitching seams (gap seams and overlapping seams). Therefore, the design of the shape of a single exposure field and the planning of the stitching trajectory of the exposure fields directly affect the macroscopic appearance of the fabricated gratings. In particular, the interference exposure method often uses the means of secondary exposure after relative rotation of the substrate and the exposure field to fabricate two-dimensional gratings. This method results in the angular overlap of two sets of macroscopic stitching seams before and after rotation, thereby forming a more complex macroscopic stitching seam pattern. More stitching seams mean more serious stray light affecting the imaging quality.

[0026] Therefore, in order to overcome the above defects, the embodiments of the present application provide a grating exposure system and method, which can improve the accuracy of fabricating micro-nano grating structures and at the same time improve the efficiency of large-area and shaped micro-nano grating structures.

[0027] Please refer to Figure 1 , Figure 1 FIG. is a schematic diagram of the system architecture of a grating exposure system 10 provided by an embodiment of the present application. The grating exposure system 10 includes: a movable stage 101, a light source module 102, a beam adjustment module 103, an exposure module 104, and a control module 105. Among them, the control module 105 can establish a communication connection with the stage 101. This communication connection can be a wired connection or a wireless connection. The specific communication connection method can be set according to actual needs. The control module 105 can send control signals to the stage 101 based on this communication connection to control the movement of the stage 101.

[0028] The movable stage 101 is used to carry the substrate 20 and drive the substrate 20 to move, so that a grating structure to be fabricated is formed on the substrate 20. The grating structure to be fabricated is formed by splicing a plurality of grating partitions.

[0029] Among them, the grating structure to be fabricated can be as Figure 2 shown, that is, the grating structure to be fabricated only includes a grating region 32, and the grating region 32 is formed by densely paving and splicing a plurality of equilateral triangular grating partitions. Of course, a plurality of grating partitions can also form a plurality of grating regions, that is, each grating region is formed by densely paving a part of the grating partitions among a plurality of grating partitions. As Figure 3 shown, the grating structure can include a grating region 22, a grating region 32, and a grating region 42, and each grating region is formed by densely paving a plurality of triangular grating partitions.

[0030] Optionally, the shape of the grating partition may also be a regular quadrilateral, such as Figure 4 shown, the grating structure may include a grating region 23, a grating region 33, and a grating region 43. Among them, the grating region 23 may include only one regular quadrilateral grating partition, that is, one grating partition may also constitute a grating region; each grating partition in the grating regions 33 and 43 is also a regular quadrilateral.

[0031] Optionally, in the case where the grating structure has multiple grating regions, the regional shapes of the grating partitions constituting each grating region may also be different. Such as Figure 5 shown, the grating structure may include a grating region 24, a grating region 34, and a grating region 44. The grating region 24 may be formed by tiling multiple equilateral triangle grating partitions, the grating region 34 may be formed by tiling multiple regular quadrilateral grating partitions, and the grating region 44 may be formed by tiling multiple regular hexagon grating partitions.

[0032] The light source module 102 is used to output a light beam.

[0033] The light beam adjustment module 103 is used to adjust the light beam to form a light spot with a target shape.

[0034] The exposure module 104 is used to use the adjusted light beam to form an exposure field with the target shape on the substrate 20 to form the grating partition.

[0035] The control module 105 is used to control the moving stage 101 to drive the substrate 20 to rotate according to a target exposure strategy, so that the exposure field with the target shape generated after rotation coincides with the exposure field with the target shape generated before rotation.

[0036] In some embodiments, the target exposure strategy at least includes the exposure order of the multiple grating partitions and the number of exposure times corresponding to each grating partition; based on this, the control module 105 can control the moving stage 101 to drive the substrate 20 to move according to the exposure order, and perform interference exposure on each grating partition for its corresponding number of exposure times in sequence.

[0037] Among them, the number of exposure times corresponding to each grating partition can be 1 or multiple times. Moreover, the number of exposure times of different grating partitions can be the same or different, and this embodiment does not limit this. When the number of exposure times corresponding to the grating partition is 1 time, a grating structure having periodicity in one direction, that is, a one-dimensional grating, can thus be formed on this grating partition of the substrate 20; when the number of exposure times corresponding to the grating partition is multiple times, for example, 2 times, a grating structure having periodicity in two directions, that is, a two-dimensional grating, can be formed on this grating partition of the substrate 20; as Figure 6 shown, the grating structure 11 can include a grating region 21 and a grating region 31. The grating partitions in the grating region 21 are one-dimensional grating structures 211, and within the regular hexagon-shaped grating partitions in the grating region 31 are two-dimensional grating structures 311. The grating partitions 31a, 31c, 31b, and other unlabeled regular hexagon regions are all grating partitions within the grating region 31. Of course, with an increase in the number of exposure times, more-dimensional grating structures can also be formed.

[0038] As Figure 3 shown, the grating region can also be all one-dimensional grating structures. The arrangement directions of the equilateral triangles and the grating line directions within each grating region are different. Generally, in order to simplify the preparation of the grating, the grating line direction in each grating partition is kept consistent with the arrangement direction of the equilateral triangle grating partition. For example, the grating line direction within the grating region 42 (i.e., Figure 3 the direction of the interference fringes shown as 421) is rotated 90 degrees clockwise relative to the grating line direction within the grating region 22 (i.e., Figure 3 the direction of the interference fringes shown as 211), and the equilateral triangle direction within the grating region 42 is also rotated 90 degrees clockwise relative to the equilateral triangle direction within the grating region 22. The grating line direction within the grating region 32 (i.e., Figure 3 the direction of the interference fringes shown as 321) is rotated 45 degrees clockwise relative to the grating line direction within the grating region 42, and the equilateral triangle direction within the grating region 32 is also rotated 45 degrees clockwise relative to the equilateral triangle direction within the grating region 42.

[0039] That is to say, each grating partition on the substrate 20 in this application can be exposed to a one-dimensional grating structure, a two-dimensional grating structure, or a more-dimensional grating structure, and this embodiment does not limit this. Among them, multiple grating partitions are arranged in a close-packed manner, and there is a gap between two adjacent grating partitions. The grating structure includes at least one of a surface relief grating structure, a holographic grating structure, and a polarizer grating. Of course, the grating structure period, duty cycle, and / or grating vector direction required in each grating partition can be set differently or the same, and can be specifically set according to actual needs, and this application will not elaborate further here.

[0040] Optionally, when at least some of the grating partitions among the multiple grating partitions have multiple exposure times, at this time, the exposure order of the multiple grating partitions can be to first perform the first exposure on all the grating partitions in sequence, and then perform more exposures on the grating partitions with multiple exposure times at one time. In other words, at this time, multiple rounds of exposure can be performed, and the number of exposure rounds is the same as the maximum number of exposure times corresponding to the grating partitions. Exemplarily, there are 10 grating partitions on the substrate 20. Among them, 5 grating partitions have 1 exposure time, 3 grating partitions have 2 exposure times, and 2 grating partitions have 4 exposure times. At this time, the maximum number of exposure times corresponding to the grating partitions is 4 times; that is to say, 4 rounds of exposure will be performed at this time. In the first round, the first interference exposure can be first performed on the 10 grating partitions. In the second round, only the 3 grating partitions are exposed for the second time. In the third round, the 2 grating partitions are exposed for the third time. In the fourth round, the 2 grating partitions are exposed for the fourth time.

[0041] Optionally, when at least some of the grating partitions among the multiple grating partitions have multiple exposure times, at this time, the exposure order of the multiple grating partitions can be to perform exposure on the next grating partition after each grating partition is exposed. For example, there are 3 grating partitions (grating partition A, grating partition B, grating partition C) on the substrate 20. Among them, the grating partition A has 2 exposure times, the grating partition B has 3 exposure times, and the grating partition C has 1 exposure time; at this time, the exposure order for these 3 grating partitions can be to perform 2 exposures on the grating partition A, then perform 3 exposures on the grating partition B, and finally perform 1 exposure on the grating partition C. In this way, the grating exposure efficiency can be improved to a certain extent.

[0042] In this method, the target exposure strategy further includes the translation parameters and rotation parameters corresponding to forming different exposure fields, where the movement parameters include the translation direction and the translation distance, and the rotation parameters include the rotation direction and the rotation angle.

[0043] Based on this, the control module 105 can control the moving stage 101 to drive the substrate to translate according to the translation direction and the translation distance corresponding to forming different exposure fields; the control module 105 is used to control the moving stage 101 to drive the substrate to rotate according to the rotation direction and the rotation angle corresponding to forming different exposure fields. Among them, the translation direction includes Figure 1in the x-axis direction and the y-axis direction, where the x-axis and the y-axis are in the same plane as the substrate 20, and the z-axis is perpendicular to the plane where the substrate 20 is located. That is to say, the control module 105 can control the moving platform to carry the substrate 20 to achieve translational motion in the x-axis, translational motion in the y-axis, and / or rotational motion around the z-axis, so as to achieve one or more exposures of different grating partitions on the substrate 20, thereby obtaining the required tiled grating structure.

[0044] Since when exposing each grating partition, it is necessary to make the exposure field coincide with each grating partition; based on this, the present application can use the beam adjustment module 103 to adjust the beam output by the light source module 102 into a light spot with a target shape that can match the regional shape of the grating partition. That is to say, the regional shape of the grating partition is the shape of the light spot that the beam needs to be adjusted to form, so that the exposure module 104 can use the adjusted beam to form an exposure field with a target shape that is the same as the regional shape of the grating partition on each grating partition of the substrate. In this way, it is possible to avoid leaving stray light on the macroscopically visible slit between adjacent grating partitions, that is, only the required grating structure is formed inside the multiple grating partitions, and a complex grating structure will not be formed in the seam between adjacent grating partitions, thereby affecting the aesthetics of the tiled polygon grating structure finally formed on the substrate 20.

[0045] Exemplarily, please refer to Figure 7 , Figure 7 There is a macroscopic seam 101 between the grating partition 1a and the grating partition 1b in

[0046] Optionally, considering the same grating partition, the control module 105 can control the rotation of the moving stage, thereby driving the substrate 20 to rotate, so as to perform multiple exposures in different directions on the same grating partition. In order to make the exposure field align with the same grating partition before and after rotation. Therefore, the regional shape of the grating partition can be preset as a regular polygon shape, so that the control module 105 can control the moving stage 101 to rotate by N times the interior angle of the regular polygon shape around the z-axis direction where the center point of the grating partition on the substrate is located, and N is a positive integer. Among them, the regular polygon is a regular polygon that can achieve tessellation, that is, the regular polygon can be an equilateral triangle, a square or a regular hexagon. In this way, when performing multiple exposures on the same grating partition on the substrate 20 to form a two-dimensional grating or a more-dimensional grating structure, the exposure fields formed by the exposure module 104 can be aligned with the same grating partition after each rotation; furthermore, it can be avoided that because the grating partition is not a regular polygon, a part of the exposure field after rotation is outside the grating partition (for example, in the seam between adjacent grating partitions or inside adjacent grating partitions), which affects the aesthetics of the grating structure finally obtained on the substrate 20.

[0047] It can be understood that since the regional shapes of each grating partition are different, when exposing different grating partitions, the beam adjustment module 103 can correspondingly adjust the beam output by the light source module 102 to form the regional shape corresponding to the grating partition. That is to say, the beam adjustment module 103 does not adjust the beam to form a light spot with the same target shape throughout the exposure process, but will correspondingly adjust the beam according to the regional shape of the grating partition that needs to be exposed to form a light spot with the same shape as the regional shape of the grating partition, so that the exposure module 104 can form an exposure field with the same shape on the corresponding grating partition on the substrate 20, thereby realizing the alignment and coincidence of the exposure field and the grating partition.

[0048] It can be understood that a photosensitive material can be coated on the surface of the substrate 20, and the photosensitive material can be a positive photoresist. After the positive photoresist on the surface of the substrate 20 is subjected to interference exposure in this embodiment, it can be cleaned by a developer, the exposed part is dissolved, and the unexposed part remains, so that an image of a micro-nano grating structure is formed on the surface of the substrate 20. Of course, the photosensitive material can also be a negative photoresist. After the positive photoresist on the surface of the substrate 20 is subjected to multiple interference exposures, it can be cleaned by a developer, the unexposed part is dissolved, and the exposed part remains, so that an image of a micro-nano grating structure can also be formed on the surface of the substrate.

[0049] In this embodiment, since the control module can control the moving stage to drive the substrate to rotate according to the target exposure strategy, so that the exposure field with the target shape generated after rotation coincides with the exposure field with the target shape generated before rotation. Thereby reducing the generation of stray light, enabling a densely paved grating structure with regular and beautiful macroscopic stitching to be finally obtained, and realizing the exposure preparation of a polygon stitching grating with low cost, low implementation difficulty and high efficiency.

[0050] Please refer to Figure 8 , Figure 8 which is a schematic diagram of the system architecture of the grating exposure system 10 provided by another embodiment of the present application. The grating exposure system 10 includes: a movable moving stage 101, a light source module 102, a spatial light modulator 103, an exposure module 104, and a control module 105. Among them, the exposure module 104 includes a beam splitter 1041, a first mirror 1042, and a second mirror 1043.

[0051] In this embodiment, the movable moving stage 101 is used to carry the substrate 20 and drive the substrate 20 to move, so that a grating structure to be prepared is formed on the substrate 20. The grating structure to be prepared is composed of a plurality of grating partitions spliced together. Among them, the grating structure to be prepared is still similar to that in the foregoing embodiment, such as Figure 2 , Figure 3 , Figure 4 and Figure 5 and other types of grating structures, which will not be elaborated here one by one.

[0052] Optionally, the beam splitter 1041 is arranged on the optical path of the modulated beam output by the spatial light modulator 103. The beam splitter 1041 is used to split the modulated beam and output the first coherent beam and the second coherent beam obtained by splitting. The first mirror 1042 is used to reflect the first coherent beam onto the substrate 20, and the second mirror 1043 is used to reflect the second coherent beam onto the substrate 20, so that the first coherent beam and the second coherent beam form the exposure field with the target shape on the substrate 20.

[0053] The control module 105 is used to control the moving stage 101 to drive the substrate 20 to rotate according to the target exposure strategy, so that the exposure field with the target shape generated after rotation coincides with the exposure field with the target shape generated before rotation. Among them, the parameters included in the target exposure strategy may include the content in the foregoing embodiment, which will not be elaborated here.

[0054] In this embodiment, the light source module 102 can be a single light source, that is, the light beam output by the light source module 102 is a single light beam. Furthermore, the spatial light modulator 103 can modulate the single light beam into a polygonal light beam that can form a shape identical to the area shape of the grating partition to be exposed currently. Understandably, a communication connection can also be established between the control module 105 and the spatial light modulator 103 ( Figure 8 this communication connection is not shown in the figure), so that according to the area shape of each grating partition in the exposure strategy during each exposure, the spatial light modulator can be controlled to adjust the single light beam into a polygonal light beam with the same area shape as the grating partition in this exposure. Further, the beam splitter 1041 can divide the polygonal light beam into two coherent light beams, namely the first coherent light beam and the second coherent light beam. The first coherent light beam and the second coherent light beam are respectively reflected by the first mirror 1042 and the second mirror 1043 into the grating partition on the substrate 20, forming an exposure field with the same shape as the grating partition, that is, making the exposure field align and coincide with the grating partition on the substrate 20.

[0055] Taking Figure 6 the grating partition layout of the grating structure in the figure as an example, the grating structure to be prepared can include a grating area 21 and a grating area 31. The grating area 21 only includes 1 regular hexagonal grating partition, and the grating area 31 includes multiple regular hexagonal grating partitions (such as Figure 6 the grating partitions 31a, 31b, and 31c shown in the figure, and Figure 6 other grating partitions not shown in the figure). The control module 105 can first control the moving stage 101 to move according to the target exposure strategy, so that an exposure field with a target shape is formed on the substrate to form the grating partition 21, that is, the substrate 20 is adjusted to the state shown in Figure 9 (a) in the figure. Furthermore, the spatial light modulator 103 modulates the light beam so that the exposure field is a regular hexagon and the size is consistent with the regular hexagon in the grating design, thereby completing the grating partition 21a. Among them, the grating structure formed in the grating partition 21a is the one-dimensional grating structure in the grating partition 21 of the grating structure to be prepared shown in Figure 6 the figure.

[0056] Subsequently, based on the target exposure strategy, the control module 105 continues to control the moving stage 101 to carry the substrate 20 to rotate clockwise by 60 degrees around the +z axis (that is, the internal angle of the regular hexagon) and translate so that the grating partition 31a is aligned and coincides with the regular hexagonal exposure field, that is, the substrate 20 is adjusted to the state shown in Figure 9 (b) in the figure. The exposure is started to expose the grating partition 31a to obtain the exposed area 31a1, and then the moving stage 101 is translated to expose the grating partition 31b to obtain the exposed area 31b1. In this way, each grating partition in the grating area 31 is exposed in a cycle.

[0057] Further, the control module 105 continues to control the moving stage 101 to carry the substrate 20 to rotate counterclockwise by 120 degrees around the +Z axis (i.e., twice the interior angle of a regular hexagon) and translate so that the grating partition 31a is aligned and coincident with the exposure field of the hexagon, that is, the substrate 20 is adjusted to the state shown in (c) of Figure 9 . Secondary exposure is performed on the exposure area 31a1 to obtain the exposure area 31a2. The latent image grating in the area 31a2 is a two-dimensional grating, and this two-dimensional grating can be the two-dimensional grating structure 311 in Figure 6 . Similarly, the main control module 105 sequentially exposes each grating partition of the area 32. Thus, the exposure of the two-dimensional gratings in each grating partition of the area 32 is completed. Similarly, the grating structures outside the grating partitions 21 and 31 on the substrate 20 are overexposed. Here, overexposure can be understood as increasing the exposure dose to a dose at which all photoresist is removed after development, so that there is no grating structure in this area, and only grating structures exist inside the grating partitions 21 and 31. Finally, the exposure substrate is developed, that is, the preparation of the grating structure of the hexagonal tiling feature in Figure 6 is completed. As shown in (d) of Figure 9 , the black area is the area on the substrate 20 without a grating structure, and the white area is the area on the substrate 20 with a grating structure.

[0058] In this embodiment, facing the fact that there are macroscopic stitching seams between adjacent sub-regions in the grating structure to be prepared, when exposing each grating partition, the alignment of the exposure field and the grating partition is performed, and the light beam used for interference exposure is adjusted by the spatial light modulator into a regular polygon light beam with the same shape as the grating partition, so as to quickly realize the adjustment of the light beam shape; to the greatest extent, it is ensured that during each exposure process, the exposure field is aligned and coincident with the grating partition, so that a corresponding grating structure can be obtained by interference exposure in each grating partition on the substrate, and at the same time, it is also ensured that there is no grating structure in the macroscopic stitching seams between adjacent grating partitions, so as to finally obtain a densely paved grating structure with regular and beautiful macroscopic stitching seams, realizing the exposure preparation of polygon stitching gratings with low cost, low implementation difficulty and high efficiency.

[0059] Please refer to Figure 10 . Figure 10 is a schematic diagram of the system architecture of the grating exposure system 10 provided by another embodiment of the present application. The grating exposure system 10 includes: a movable moving stage 101, a collimated light source module 102, a perforated mask 103, a grating mask 104, and a control module 105.

[0060] In this embodiment, the movable stage 101 is used to carry the substrate 20 and drive the substrate 20 to move, so that a grating structure to be fabricated is formed on the substrate 20. The grating structure to be fabricated is composed of a plurality of grating partitions spliced together. Among them, the grating structure to be fabricated is still similar to that in the previous embodiment, such as Figure 2 , Figure 3 , Figure 4 and Figure 5 and other types of grating structures, which will not be elaborated here one by one.

[0061] The collimated light source module 102 is used to output a collimated light beam; the shape of the hollowed-out area of the hollow mask 103 is the same as the target shape, where the target shape is still the regular polygon described in the previous embodiment; the hollowed-out area of the hollow mask 103 is used to transmit the collimated light beam, so that the collimated light beam passing through the hollow mask 103 becomes a regular polygon light beam, that is, the light spot formed by the collimated light beam passing through the hollow mask 103 is in the shape of a regular polygon. Further, the grating mask 104 is arranged on the optical path of the collimated light beam output by the hollow mask. The periodic structure of the grating mask 104 diffracts the collimated light beam onto the substrate 20 based on the Talbot effect to form an exposure field of the target shape. Among them, the periodic structure of the grating mask 104 is the Figure 10 raised structures above and below the grating mask 104 in . The grating mask 104 can be a phase mask or an amplitude mask or other types of masks, and this embodiment will not elaborate on examples one by one here.

[0062] The control module 105 is used to control the stage 101 to drive the substrate 20 to rotate according to the target exposure strategy, so that the exposure field of the target shape generated after rotation coincides with the exposure field of the target shape generated before rotation.

[0063] Among them, the parameters included in the target exposure strategy can refer to the content in the previous embodiment. It should be noted that since in the target exposure strategy, in the grating structure to be fabricated including multiple grating regions, the regional shapes of the grating partitions constituting each grating region can be different, that is to say, the hollow mask 103 used in this embodiment will also be different.

[0064] Based on this, the target exposure strategy can include the order of multiple rounds of exposure, and interference exposure is performed on multiple grating partitions with the same regional shape in sequence. After replacing the hollow mask 103 for multiple grating partitions with another regional shape, another round of interference exposure is performed. In this way, it is possible to avoid problems such as low grating exposure efficiency caused by alternating exposure of grating partitions with different regional shapes and frequent replacement of the hollow mask 103, that is, the grating exposure efficiency is improved.

[0065] In some embodiments, after completing the interference exposure of multiple grating partitions of the same regional shape, the control module 105 may output a prompt message for prompting relevant personnel to manually replace the currently used hollow mask 103 with the hollow mask required for the next round. For example, if the hollow area of the currently used hollow mask 103 is an equilateral triangle, and the multiple grating partitions for the next round of interference exposure are all regular hexagons, then relevant personnel can be prompted to manually replace the hollow mask with a hollow area of a regular hexagon through this prompt message.

[0066] In some other possible embodiments, the hollow mask 103 may be placed on a movable replacement device (not shown in Figure 10 ), and the movable replacement device also places a hollow mask having the same regional shape as other sub-regions in the target exposure strategy. Of course, the movable replacement device can establish a communication connection with the control module 105 so that the control module 105 can send a control signal to control the rotation of the movable replacement device. Based on this, after completing the interference exposure of multiple grating partitions of the same regional shape, the control module 105 can control the rotation of the movable replacement device, rotate the currently used hollow mask 103 away from the optical path of the output beam of the collimating light source module 102, and rotate the hollow mask required for the multiple sub-regions of the same shape that need to be interferentially exposed in the next round to the optical path of the output beam of the collimating light source module 102, that is, replace the hollow mask 103 used in the previous round. In this way, the automatic replacement of the hollow mask 103 is realized, which ensures the preparation of the grating structure with a mixed regular polygon tiling, and at the same time improves the exposure efficiency of the grating structure with a mixed regular polygon tiling.

[0067] In this embodiment, facing the fact that there are macroscopic seams between adjacent sub-regions in the grating structure to be prepared, when exposing each grating partition, the alignment of the exposure field and the grating partition is performed, and the beam used for interference exposure is adjusted into a regular polygon beam with the same shape as the grating partition by using the hollow mask; then the control module can control the moving stage to drive the substrate to rotate according to the target exposure strategy so that the exposure field of the target shape generated after rotation coincides with the exposure field of the target shape generated before rotation. Thereby reducing the generation of stray light, and finally enabling a tiled grating structure with regular and beautiful macroscopic seams to be obtained. Since the cost of the hollow mask is low, the exposure preparation of a polygon-seamed grating with low cost, low implementation difficulty and high efficiency is realized.

[0068] Please refer to Figure 11 , Figure 11 which is a schematic flowchart of a grating exposure method provided by an embodiment of the present application, applied to the grating exposure system mentioned in any of the foregoing embodiments. Next, it will be combined with Figure 4The grating exposure method provided by the embodiments of the present application is elaborated in detail. The grating exposure method may include the following steps:

[0069] Step S310: Output a light beam through a light source module.

[0070] Step S320: Adjust the light beam through a light beam adjustment module to form a light spot with a target shape.

[0071] Step S330: Use the adjusted light beam through an exposure module to form an exposure field with the target shape on the substrate, so as to form a grating partition in the grating structure to be prepared.

[0072] Step S340: According to a target exposure strategy, control the movable stage through a control module to drive the carried substrate to rotate, so that the exposure field with the target shape generated after rotation coincides with the exposure field with the target shape generated before rotation.

[0073] In this embodiment, the specific implementation manners in steps S310 to S340 may refer to the content in the foregoing embodiments, and will not be elaborated herein.

[0074] In this embodiment, the movable stage in the grating exposure system is used to carry the substrate and drive the substrate to move, so that a grating structure to be prepared is formed on the substrate. The grating structure to be prepared is composed of a plurality of grating partitions spliced together; the light source module is used to output a light beam; the light beam adjustment module is used to adjust the light beam to form a light spot with a target shape; the exposure module is used to use the adjusted light beam to form an exposure field with a target shape on the substrate to form a grating partition; the control module is used to control the stage to drive the substrate to rotate according to a target exposure strategy, so that the exposure field with the target shape generated after rotation coincides with the exposure field with the target shape generated before rotation. Thereby, the generation of stray light is reduced, so that a densely paved grating structure with regular and beautiful macroscopic seams can be finally obtained, realizing the exposure preparation of a polygon-seamed grating with low cost, low implementation difficulty and high efficiency.

Claims

1. A grating exposure system, characterized in that, The grating exposure system includes: A movable stage for carrying a substrate and driving the substrate to move so as to form a grating structure to be prepared on the substrate, and the grating structure to be prepared is composed of a plurality of grating partitions spliced together; A light source module for outputting a light beam; A light beam adjustment module for adjusting the light beam to form a light spot with a target shape; An exposure module for using the adjusted light beam to form an exposure field with the target shape on the substrate to form the grating partition; A control module for controlling the stage to drive the substrate to rotate according to a target exposure strategy so that the exposure field with the target shape generated after rotation coincides with the exposure field with the target shape generated before rotation.

2. The grating exposure system according to claim 1, characterized in that, The target exposure strategy at least includes the exposure sequence of the plurality of grating partitions and the number of exposure times corresponding to each grating partition; The control module is used to control the stage to drive the substrate to move according to the exposure sequence and perform exposure on each grating partition for its corresponding number of exposure times in sequence.

3. The grating exposure system according to claim 2, characterized in that, The target exposure strategy further includes the translation parameters and rotation parameters corresponding to forming different exposure fields, the movement parameters include the translation direction and the translation distance, and the rotation parameters include the rotation direction and the rotation angle; The control module is used to control the stage to drive the substrate to perform translation according to the translation direction and the translation distance corresponding to forming different exposure fields; The control module is used to control the stage to drive the substrate to rotate according to the rotation direction and the rotation angle corresponding to forming different exposure fields.

4. The grating exposure system according to claim 3, wherein the target shape is a regular polygon shape, and the rotation angle is N times the interior angle of the regular polygon shape, where N is a positive integer.

5. The grating exposure system according to claim 1, characterized in that, A plurality of the exposure fields are formed on the substrate, and the plurality of grating partitions formed by the plurality of exposure fields on the substrate are arranged in a close-packed manner.

6. The grating exposure system according to any one of claims 1-5, wherein the beam adjustment module is a spatial light modulator, and the spatial light modulator is used to modulate the beam to form a light spot of the target shape.

7. The grating exposure system according to claim 6, wherein the exposure module includes a beam splitter, a first mirror, and a second mirror; The beam splitter is disposed on the optical path of the modulated beam output by the spatial light modulator, and the beam splitter is used to split the modulated beam and output a first coherent beam and a second coherent beam obtained by splitting; The first mirror is used to reflect the first coherent beam onto the substrate, and the second mirror is used to reflect the second coherent beam onto the substrate, so that the first coherent beam and the second coherent beam form an exposure field of the target shape on the substrate.

8. The grating exposure system according to any one of claims 1-5, wherein the beam adjustment module is a perforated mask, the shape of the perforated area of the perforated mask is the same as the target shape, and the perforated area of the perforated mask is used to transmit the beam.

9. The grating exposure system according to claim 8, characterized in that, The light source module is a collimated light source module, and the exposure module is a grating mask; The collimated light source module is used to output a collimated light beam; The grating mask is arranged on the optical path of the output collimated light beam of the hollow mask, and the periodic structure of the grating mask diffracts the collimated light beam onto the substrate to form an exposure field with the target shape based on the Talbot effect.

10. A grating exposure method, characterized in that, Applied to the grating exposure system according to any one of claims 1-9, the method includes: Outputting a light beam through the light source module; Adjusting the light beam through the light beam adjustment module to form a light spot with a target shape; Using the adjusted light beam through the exposure module to form an exposure field with the target shape on the substrate to form a grating partition in the grating structure to be prepared; Controlling the movable stage to drive the carried substrate to rotate according to the target exposure strategy through the control module so that the exposure field with the target shape generated after rotation coincides with the exposure field with the target shape generated before rotation.

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