Method for pattern correction of a mask, system and medium therefor

Abstract

The disclosure provides a mask pattern correction method, which relates to the field of semiconductor manufacturing and comprises the following steps: obtaining a square target pattern; limiting the distance between adjacent photoetching patterns of the target pattern in a first direction; not limiting the distance between adjacent photoetching patterns in a second direction; simulating a profile in the first and second directions, and determining whether the interval distance between the profile and the boundary of the target pattern exceeds a preset distance threshold; widening or narrowing the target pattern in the second direction according to the interval distance to obtain a reference pattern; dividing the reference pattern into multiple sub-edges along two opposite edges in the second direction to obtain multiple segments of sub-edges; performing optical proximity correction on the reference pattern, updating the photoetching pattern and the pattern simulation profile, and making the multiple segments of sub-edges and the edge of the reference pattern that is not divided as movable edges; determining whether the interval distance between the updated pattern simulation profile and the boundary of the target pattern is less than the preset distance threshold; and outputting the updated photoetching pattern if the interval distance is less than the preset distance threshold. The method makes the simulation profile of the updated photoetching pattern converge to the target pattern.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of semiconductor manufacturing, and in particular, to a mask pattern correction method, system and medium. BACKGROUND

[0002] The photolithography process is an important process in the semiconductor device manufacturing process; the photolithography process is to transfer the pattern on the photomask to the photoresist layer by exposure and development. However, in the photolithography process, when the pattern on the photomask is transferred to the photoresist layer by exposure and development, due to the imperfection of the optical system and the diffraction effect, the pattern on the photoresist layer will deviate from the pattern on the photomask, which will affect the performance of the product when the pattern on the photoresist is used to form the product.

[0003] Optical proximity correction (OPC) is a photolithography enhancement technique used in semiconductor manufacturing, which aims to correct the distortion of the photolithography pattern caused by diffraction effect and other optical effects, to ensure that the circuit pattern on the wafer is as consistent as possible with the original design. In actual production process, after the OPC step, mask rule constraints (MRC) need to be checked to ensure that the pattern is suitable for the mask preparation process, which usually includes the minimum line width (min Width), line spacing (min Space) and the minimum value of the corner-to-corner spacing of the pattern. However, the introduction of MRC will have a great impact on the convergence of OPC, affecting the accuracy of correction, resulting in large errors, and thus affecting the performance of the product. SUMMARY

[0004] In view of the above problems, a new mask pattern correction method, system and medium are needed.

[0005] According to a first aspect of the present disclosure, a mask pattern correction method is provided, comprising:

[0006] obtaining a target pattern, the target pattern being a square, along a first direction, the photolithography patterns adjacent to the target pattern are limited by a limited distance, the distance between the pattern simulation profile in this direction and the boundary of the target pattern exceeds a preset distance threshold; along a second direction, the photolithography patterns adjacent to the target pattern are not limited by a limited distance, the distance between the pattern simulation profile in this direction and the boundary of the target pattern exceeds a preset distance threshold, the first direction is perpendicular to the second direction;

[0007] According to a spacing distance between the pattern simulation profile and a boundary of the target pattern along the second direction, the target pattern is widened or narrowed to obtain a rectangular reference pattern, the reference pattern comprising a first side, a second side, a third side and a fourth side, the first side opposite to the second side along the second direction, the third side opposite to the fourth side along the first direction;

[0008] The first side and the second side are respectively divided to obtain a plurality of sub-sides;

[0009] The reference pattern is subjected to optical proximity correction to update the lithography pattern and the pattern simulation profile, adjacent updated lithography patterns being limited by a limiting distance along the first direction;

[0010] Whether the spacing distance of the updated pattern simulation profile to the boundary of the target pattern is less than a preset distance threshold along the first direction and the second direction is determined, and if the result is yes, the updated lithography pattern is output; and

[0011] If the result is no, the step of obtaining the reference pattern is returned,

[0012] In the step of subjecting the reference pattern to optical proximity correction, the plurality of sub-sides, the third side and the fourth side are all movable sides.

[0013] Optionally, evaluation points are further arranged at midpoints of the first side, the second side, the third side and the fourth side,

[0014] In the step of subjecting the reference pattern to optical proximity correction, the reference pattern is subjected to optical proximity correction according to the evaluation points.

[0015] Optionally, in the step of obtaining the reference pattern:

[0016] When the pattern simulation profile is inside an edge of the target pattern along the second direction, the target pattern is widened according to the spacing distance,

[0017] When the pattern simulation profile is outside the edge of the target pattern along the second direction, the target pattern is narrowed according to the spacing distance.

[0018] Optionally, the step of dividing the first side and the second side to obtain a plurality of sub-sides comprises:

[0019] The first side is divided to obtain a first sub-side and a second sub-side; and

[0020] The second side is divided to obtain a third sub-side and a fourth sub-side.

[0021] Optionally, in the step of respectively dividing the first edge and the second edge to obtain a plurality of sub-edges, the first edge and the second edge are both divided.

[0022] Optionally, the system further comprises:

[0023] obtaining a distribution map of a plurality of target patterns;

[0024] performing optical proximity correction on the plurality of target patterns to obtain lithography patterns of the plurality of target patterns, wherein adjacent lithography patterns of the target patterns are limited by a limiting distance; and

[0025] obtaining a pattern simulation profile according to the lithography patterns of the target patterns,

[0026] wherein the target patterns are filtered according to a result of judging whether the pattern simulation profile converges to the target patterns.

[0027] Optionally, the mask plate is used to form a hole layer of a semiconductor device.

[0028] According to a second aspect of the present disclosure, a pattern correction system of a mask plate is provided, comprising:

[0029] a target pattern obtaining module configured to obtain a target pattern, the target pattern being a square, along a first direction, adjacent lithography patterns of the target pattern being limited by a limiting distance, a distance between a pattern simulation profile in the first direction and a boundary of the target pattern exceeding a preset distance threshold; along a second direction, adjacent lithography patterns of the target pattern not being limited by the limiting distance, a distance between the pattern simulation profile in the second direction and the boundary of the target pattern exceeding the preset distance threshold, the first direction being perpendicular to the second direction;

[0030] a reference pattern obtaining module configured to widen or narrow the target pattern along the second direction according to a distance between the pattern simulation profile and the boundary of the target pattern to obtain a reference pattern in a rectangular shape, the reference pattern comprising a first edge, a second edge, a third edge and a fourth edge, the first edge being opposite to the second edge along the second direction, the third edge being opposite to the fourth edge along the first direction;

[0031] a dividing module configured to respectively divide the first edge and the second edge to obtain a plurality of sub-edges;

[0032] an optical proximity correction module configured to perform optical proximity correction on the reference pattern to update the lithography patterns and the pattern simulation profile, along the first direction, adjacent updated lithography patterns being limited by the limiting distance;

[0033] a judging module, configured to judge whether a distance between the updated pattern simulation profile and a boundary of the target pattern is less than a preset distance threshold along the first direction and the second direction respectively, and output the updated lithography pattern if the judging result is yes, and return to the step of obtaining the reference pattern in the reference pattern obtaining module if the judging result is no,

[0034] In the step of performing optical proximity correction on the reference pattern, the multi-segment sub-edge, the third edge and the fourth edge are all movable edges.

[0035] According to a third aspect of the present disclosure, a computer readable storage medium is provided, which stores a computer program. The computer program is executed by a processor to implement the steps of the method as described above.

[0036] One of the above technical solutions has the following unexpected technical effects:

[0037] In the process of optical proximity correction, the minimum mask size rule value needs to be introduced to limit the distance between adjacent lithography patterns along the first direction to be greater than a limit distance. Due to the introduction of the limit distance, the simulation profile of the lithography pattern cannot converge to the target pattern, therefore, the first edge and the second edge of the square target pattern are moved along the second direction according to the distance between the simulation profile and the target pattern to widen or narrow the target pattern to obtain a reference pattern, the first edge and the second edge of the reference pattern are segmented, so that the number of movable edges of the reference pattern is greater than the number of movable edges of the rectangle, the degree of freedom of optical proximity correction is increased, the reference pattern is taken as the target to perform optical proximity correction, and the condition of the limit distance is superimposed, so that the simulation profile of the updated lithography pattern can converge to the target pattern. While ensuring that the lithography pattern meets the minimum mask size rule value, the convergence and accuracy of the target pattern can be improved, the accuracy of lithography is ensured, and the performance of the product is further ensured.

[0038] It should be noted that the above general description and the following detailed description are only exemplary and explanatory and cannot limit the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0039] The above and other objects, features and advantages of the present application will become more apparent from the following description of embodiments of the present application taken in conjunction with the accompanying drawings, in which:

[0040] Figure 1 A pattern diagram after the step of optical proximity correction in the related art is shown;

[0041] Figure 2 A pattern diagram after the step of optical proximity correction in the related art is shown;

[0042] Figure 3 A pattern diagram after introducing a minimum size rule value limit in the related art is shown;

[0043] Figure 4 A pattern diagram after introducing a minimum size rule value limit in the related art is shown; Figure 3 An enlarged structure diagram of a target pattern and a pattern simulation profile in the embodiment of the present disclosure is shown;

[0044] Figure 5 A step diagram of a pattern correction method of a mask plate in the embodiment of the present disclosure is shown;

[0045] Figure 6 A pattern diagram after an optical proximity correction step in the embodiment of the present disclosure is shown;

[0046] Figure 7 A diagram of a reference pattern in the embodiment of the present disclosure is shown;

[0047] Figure 8 A diagram of edge segmentation of a reference pattern in the embodiment of the present disclosure is shown;

[0048] Figure 9 A diagram of evaluation point setting in the embodiment of the present disclosure is shown;

[0049] Figure 10 A diagram of a lithography pattern of a target pattern in the embodiment of the present disclosure is shown;

[0050] Figure 11 A diagram of a converged updated pattern simulation profile to a target pattern in the embodiment of the present disclosure is shown;

[0051] Figure 12 A structure diagram of a pattern correction system of a mask plate in the embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0052] The present application will be described in more detail by referring to the attached drawings. In each of the drawings, like elements are designated by like reference numerals. Each part in the drawings is not drawn to scale for the sake of clarity. In addition, some well-known parts can not be shown.

[0053] Many specific details of the present disclosure are described below in order to provide a thorough understanding of the present disclosure. However, as will be understood by persons of ordinary skill in the art, the present disclosure can be implemented without these specific details.

[0054] Also, certain terms have been used herein for brevity, clarity and understanding. However, no unnecessary limitations are to be implied therefrom because such terms are used for descriptive purposes only and are intended to be broadly construed. Moreover, the terms "first", "second", third", etc. that are used in the description and the claims are not used to denote any sequential or chronological order, but are merely used to distinguish one element from another.

[0055] In addition, it should also be noted that, in this document, relational terms such as first and second, and the like can be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0056] The application can be presented in a variety of ways and some example of which will be described below.

[0057] Figure 1 With Figure 2 A schematic diagram of a pattern after an optical proximity correction step in the related art is shown.

[0058] In the related art, when a hole layer in a chip needs to be made, a mask of the hole layer is needed, the hole layer including a contact (CT) layer and a via layer, wherein the contact CT is a hole for connecting between a metal line and a transistor, and the via is a hole for connecting between different metal layers. In the manufacturing process of an integrated circuit, a model-based optical proximity correction (OPC) is widely used from a 90nm technology node. See Figure 1 , the target pattern 10 is a square, and evaluation points 11 are respectively set at the midpoints of the 4 sides of the target pattern 10. If the 4 sides of the target pattern 10 are respectively segmented, 8 movable sides are obtained, and then the target pattern 10 is subjected to OPC to obtain a lithography pattern (or mask pattern) 12 of the target pattern 10, and then a pattern simulation contour 13 is obtained based on the lithography pattern 12. However, the interval distance between the pattern simulation contour 13 and the evaluation points 11 exceeds a preset distance threshold, and at this time, the pattern simulation contour 13 is not converged to the target pattern 10.

[0059] Referring to Figure 2 , based on the consideration of convergence, when making the mask plate of the hole layer, the 4 edges of the target pattern 10 are generally not segmented respectively, so in the OPC process, the 4 edges can only move as a whole, and the iterative calculation is constantly carried out until the pattern simulation contour 13 converges to the target pattern 10, and the final lithography pattern 12 is a rectangle.

[0060] Figure 3 The pattern schematic diagram after the introduction of the minimum size rule value limit in the related art is shown, Figure 4 The zoomed-in structure schematic diagram of the target pattern and the pattern simulation contour in Figure 3 is shown.

[0061] Referring to Figure 3 , with the advancement of technology nodes, the layout complexity and density of the hole layer gradually increase, for example, along the X-axis direction, the distance between two adjacent target patterns 10 becomes closer and closer. However, after the introduction of the MRC, the OPC correction process will be limited by the MRC. For example, along the X-axis direction, the distance between two adjacent lithography patterns 12 cannot be less than the limit distance D, and after the OPC, the pattern simulation contour 13 calculated according to the lithography pattern 12 does not converge to the target pattern 10.

[0062] Referring to Figure 4, the size of the graphic simulation contour 13 is smaller along the X-axis direction, and the size of the graphic simulation contour 13 is larger along the Y-axis direction. Specifically, the distance difference between the graphic simulation contour 13 and the evaluation point 11 on the upper edge of the target graphic 10 is d1, the distance difference between the graphic simulation contour 13 and the evaluation point 11 on the lower edge of the target graphic 10 is d2, the distance difference between the graphic simulation contour 13 and the evaluation point 11 on the left edge of the target graphic 10 is d3, and the distance difference between the graphic simulation contour 13 and the evaluation point 11 on the right edge of the target graphic 10 is d4. In some examples, if the graphic simulation contour 13 is located outside the edge of the target graphic 10, the distance difference value is positive, and if the graphic simulation contour 13 is located inside the edge of the target graphic 10, the distance difference value is negative, wherein d1 is 2.9 nm, d2 is 2.9 nm, d3 is -1.4 nm, and d4 is -2.4 nm. Therefore, the interval distance between the graphic simulation contour 13 and the boundary of the target graphic 10 is -3.8 nm along the X-axis direction, and the interval distance between the graphic simulation contour 13 and the boundary of the target graphic 10 is 5.8 nm along the Y-axis direction. However, the interval distance between the graphic simulation contour 13 and the boundary of the target graphic 10 along the X-axis and the Y-axis cannot exceed the preset distance threshold value, and the preset distance threshold values of the two axes can be the same or different. Assuming that the preset distance threshold values of the two axes are both 1 nm, the interval distance exceeds 1 nm along the X-axis direction or the Y-axis direction in this example. This non-convergence condition can result in a contact area with the conductive material of the hole layer in the semiconductor device that does not meet the requirements, ultimately affecting the yield of the product. There are two methods to solve this problem at present, the first is to reduce the standard of MRC, and the second is to use inverse lithography technology (ILT) to seek a better optical solution. However, these methods not only consume time but also cost a lot of money. Therefore, there is an urgent need for a simple, efficient and low-cost method to solve this problem.

[0063] In view of the above problems, the present disclosure provides a new mask plate pattern correction method and system.

[0064] Figure 5 The steps of the mask plate pattern correction method of the embodiment of the present disclosure are shown.

[0065] Referring to Figure 5 The mask plate pattern correction method of the embodiment of the present disclosure comprises:

[0066] In step S01, a target pattern is acquired. The target pattern is a square, and along a first direction, the lithography patterns of adjacent target patterns are limited by a limited distance, and the distance between the pattern simulation profile in the direction and the boundary of the target pattern exceeds a preset distance threshold. Along a second direction, the lithography patterns of adjacent target patterns are not limited by a limited distance, and the distance between the pattern simulation profile in the direction and the boundary of the target pattern exceeds a preset distance threshold. The first direction is perpendicular to the second direction, and the first direction can be one of the X-axis direction and the Y-axis direction, and the second direction can be the other of the X-axis direction and the Y-axis direction.

[0067] In step S02, a reference pattern is obtained. Along the second direction, the target pattern is widened or narrowed according to the distance between the pattern simulation profile and the boundary of the target pattern to obtain a rectangular reference pattern. The reference pattern includes a first side, a second side, a third side and a fourth side. Along the second direction, the first side is opposite to the second side, and along the first direction, the third side is opposite to the fourth side.

[0068] In step S03, the edges of the reference pattern are segmented. The first side and the second side are segmented respectively to obtain a plurality of sub-sides.

[0069] In step S04, the reference pattern is subjected to optical proximity correction. After correction, the lithography pattern and the pattern simulation profile can be updated, and along the first direction, the updated lithography patterns are limited by a limited distance.

[0070] In step S05, it is determined whether the pattern simulation profile converges to the target pattern. Along the first direction and the second direction, it is respectively determined whether the distance between the updated pattern simulation profile and the boundary of the target pattern is less than a preset distance threshold. If the determination result is yes, step S06 is performed to output the updated lithography pattern, and if the determination result is no, step S02 is returned.

[0071] The steps of the pattern correction method of the mask plate according to the embodiments of the present disclosure will be described in detail below. Figures 6 to 11 The steps of the pattern correction method of the mask plate according to the embodiments of the present disclosure will be described in detail below.

[0072] Figure 6 A schematic diagram of the embodiments of the present disclosure after the optical proximity correction step is shown, wherein Figure 6 Only a part of the target pattern and the lithography pattern is shown.

[0073] Referring to Figure 6, first, the target pattern distribution of the hole layer is obtained, wherein the distance between adjacent first target patterns 111 along the X-axis direction is L1, and the distance between adjacent second target patterns 112 along the X-axis direction is L2, wherein L2 is less than L1, and L2 is, for example, the minimum size (min.rule) of the design distance between adjacent target patterns. In this embodiment, the first target pattern 111 and the second target pattern 112 are both squares. The optical proximity correction is performed on each target pattern respectively to obtain a plurality of lithography patterns, including a first lithography pattern 121 and a second lithography pattern 122, wherein the distance between adjacent lithography patterns is not less than the limiting distance D. Since L1 is large, the limiting distance D has little effect on the optical proximity correction here, and the pattern simulation profile 131 obtained according to the first lithography pattern 121 converges to the first target pattern 111. However, the value of L2 is too small, and the limiting distance D has a large effect on the optical proximity correction here, and the pattern simulation profile 132 obtained according to the second lithography pattern 122 cannot converge to the second target pattern 112. The target pattern that does not converge is selected as the target pattern according to the result of judging whether the pattern simulation profile converges to the target pattern, and in this embodiment, the second target pattern 112 is the target pattern, and accordingly, the pattern simulation profile 132 is the pattern simulation profile of the target pattern. The interval distance between the pattern simulation profile 132 and the boundary of the second target pattern 112 exceeds the preset distance threshold, and the description of the interval distance and the preset distance threshold can be referred to the description of the interval distance and the preset distance threshold. Figure 4 It should be noted that in this embodiment, the design distance between the adjacent first target pattern 111 and the second target pattern 112 along the Y-axis direction is greater than the minimum size (min.rule), and after the optical proximity correction, the distance between the lithography patterns along the Y-axis direction is also greater than the limiting distance D, so it can be regarded as that the distance between the adjacent lithography patterns along the Y-axis direction is not limited by the limiting distance D. While along the X-axis direction, the distance between the lithography patterns cannot be further narrowed, so it can be regarded as that the distance between the adjacent lithography patterns along the X-axis direction is limited by the limiting distance D. In addition, if the design distance between the adjacent target patterns along the X-axis and Y-axis directions is the minimum size (min.rule), after the optical proximity correction, the distance between the lithography patterns along the X-axis and Y-axis directions is limited by the limiting distance D, and instead, the edge profile does not converge. Moreover, the specific values of the minimum size (min.rule) along the X-axis and Y-axis directions and the limiting distance D can be the same or different, and a person skilled in the art can set them according to needs.

[0074] Figure 7 A schematic diagram of a reference pattern of an embodiment of the present disclosure is shown.

[0075] Reference is made to Figure 7Since the graphic simulation contour 132 is located outside the edge of the second target graphic 112 along the Y-axis direction, the second target graphic 112 is narrowed along the Y-axis direction according to the size of the interval distance (the size of the distance by which the graphic simulation contour 132 is located outside the edge), thereby obtaining the reference pattern 140. The reference pattern 140 is a rectangle, including a first side L10, a second side L20, a third side L30, and a fourth side L40. The first side L10 and the second side L20 are long sides, and opposite to each other along the Y-axis direction. The third side L30 and the fourth side L40 are short sides, and opposite to each other along the X-axis direction.

[0076] In some other embodiments, if the graphic simulation contour 132 is located inside the edge of the second target graphic 112 along the Y-axis direction, the second target graphic 112 is widened along the Y-axis direction according to the size of the interval distance (the size of the distance by which the graphic simulation contour 132 is located inside the edge), thereby obtaining the reference pattern 140.

[0077] Figure 8 A schematic diagram of edge segmentation of a reference pattern of an embodiment of the present disclosure is shown.

[0078] Referring to Figure 8 The first side L10 and the second side L20 are divided into multiple sub-sides respectively. In this embodiment, the first side L10 is divided into a first sub-side L11 and a second sub-side L12, and the second side L20 is divided into a third sub-side L21 and a fourth sub-side L22. The first sub-side L11, the second sub-side L12, the third sub-side L21, the fourth sub-side L22, the third side L30, and the fourth side L40 are all movable free sides in the subsequent OPC process.

[0079] Figure 9 A schematic diagram of evaluation point setting of an embodiment of the present disclosure is shown.

[0080] Referring to Figure 9 Evaluation points 141 (reference evaluation points) are set at the midpoints of the first side L10, the second side L20, the third side L30, and the fourth side L40 of the reference pattern 140. Since the first side L10 has been divided into the first sub-side L11 and the second sub-side L12, and the second side L20 has been divided into the third sub-side L21 and the fourth sub-side L22, theoretically, an evaluation point should be set at the midpoint of each free side. However, in order to make the final pattern simulation contour circular, the number of evaluation points needs to be set to four, thereby determining the circular contour. Therefore, in this embodiment, the evaluation points on the first sub-side L11 and the second sub-side L12 are merged and centered, and the evaluation points on the third sub-side L21 and the fourth sub-side L22 are merged and centered.

[0081] In addition, four evaluation points 110 (target evaluation points) are arranged on the second target pattern 112, which are located at the midpoints of the four sides of the square, and two of the evaluation points 110 coincide with the evaluation points 141 on the third side L30 and the fourth side L40. The evaluation points 110 are used to detect whether the pattern simulation profile converges to the target pattern in the subsequent steps.

[0082] Figure 10 A schematic diagram of a lithography pattern of a target pattern of an embodiment of the present disclosure is shown.

[0083] Referring to Figure 10 The reference pattern 140 is optically proximity corrected according to the evaluation points 141 on each side of the reference pattern 140, so as to obtain an updated lithography pattern 150. Since the first sub-side L11, the second sub-side L12, the third sub-side L21, the fourth sub-side L22, the third side L30 and the fourth side L40 are all movable free sides in the subsequent OPC process, after the OPC, the updated lithography pattern 150 is a hexagon in a T-shaped structure.

[0084] Figure 11 A schematic diagram showing that the updated pattern simulation profile converges to the target pattern of an embodiment of the present disclosure is shown.

[0085] The OPC correction is performed with the reference evaluation points 141 as the target. In theory, the updated pattern simulation profile should pass through or be closer to the reference evaluation points 141, so as to converge to the reference pattern 140. However, due to the introduction of the MRC rule, the adjacent updated lithography patterns 150 are limited by a limited distance D in the X-axis direction, i.e., the limited distance D limits the OPC correction. Therefore, in the Y-axis direction, after the reference pattern 140 is obtained by narrowing the second target pattern 112, the updated pattern simulation profile is located outside the edge of the reference pattern 140 and falls into or is closer to the target evaluation points 110, so as to converge to the second target pattern 112.

[0086] Further, it is judged whether the interval distance of the updated pattern simulation profile to the boundary of the second target pattern 112 is less than the preset distance threshold. If the judgment result is yes, the updated lithography pattern 150 is output, and if the judgment result is no, the step of obtaining the reference pattern 140 is returned, and the widening or narrowing distance of the second target pattern 112 is adjusted again according to the updated interval distance. Through continuous adjustment of the widening or narrowing distance, segmentation of the edge and OPC correction, the non-converged pattern is finally converged.

[0087] In the embodiment, it is needed to determine the restriction direction of the MRC rule (usually the min.rule direction) as the X-axis direction, then widen or narrow the target pattern in the Y direction perpendicular to the X-axis direction to obtain the reference pattern, when the distance between the updated pattern simulation profile and the target pattern along the Y-axis direction is less than the preset distance threshold, the convergence along the X-axis direction will also be improved. For example, in the embodiment, the distance between the final pattern simulation profile and the target pattern boundary along the X-axis direction is -0.6 nm, and the distance between the final pattern simulation profile and the target pattern boundary along the Y-axis direction is 0.4 nm. Compared with the distance between the target pattern and the initial pattern simulation profile, (3.8-0.6) / 3.8>84.2%, (5.8-0.4) / 5.8>93.1%, thus, the convergence along the X-axis direction is improved by more than 84.2% and the convergence along the Y-axis direction is improved by more than 93.1% relative to the target pattern. Figure 4 Figure 4

[0088] Figure 12 The structure schematic diagram of the pattern correction system of the mask plate is shown.

[0089] Referring to Figure 12 , the pattern correction system of the mask plate of the embodiment of the disclosure includes: a target pattern acquisition module 210, a reference pattern acquisition module 220, a segmentation module 230, an optical proximity correction module 240 and a judgment module 250.

[0090] The target pattern acquisition module 210 is used to acquire the target pattern, the target pattern is a square, along a first direction, the photolithography patterns of adjacent target patterns are limited by a restriction distance, the distance between the pattern simulation profile in the direction and the boundary of the target pattern exceeds a preset distance threshold; along a second direction, the photolithography patterns of adjacent target patterns are not limited by the restriction distance, the distance between the pattern simulation profile in the direction and the boundary of the target pattern exceeds the preset distance threshold, and the first direction is perpendicular to the second direction.

[0091] The reference pattern acquisition module 220 is used to widen or narrow the target pattern along the second direction according to the distance between the pattern simulation profile and the boundary of the target pattern to obtain a rectangular reference pattern, the reference pattern includes a first side, a second side, a third side and a fourth side, along the second direction, the first side is opposite to the second side, and along the first direction, the third side and the fourth side are opposite.

[0092] The segmentation module 230 is used to respectively segment the first side and the second side to obtain a plurality of sub-sides.

[0093] The optical proximity correction module 240 is used to perform optical proximity correction on the reference pattern to update the photolithography pattern and the pattern simulation profile, and along the first direction, adjacent updated photolithography patterns are limited by the restriction distance. ​​

[0094] The judging module 250 is configured to judge whether the interval distance of the updated pattern simulation profile to the boundary of the target pattern is less than the preset distance threshold along the first direction and the second direction respectively, and output the updated lithography pattern if the judgment result is yes, and return to the step of obtaining the reference pattern in the reference pattern obtaining module if the judgment result is no.

[0095] The pattern correction system of the mask plate can correct the pattern of the mask plate, for example, the mask plate of a hole layer in a semiconductor manufacturing process, by using the pattern correction method of the mask plate according to the embodiments of the present disclosure.

[0096] The embodiments of the present disclosure also provide a computer readable storage medium having a computer program stored thereon, and the computer program is executed by a processor to implement the steps of the pattern correction method of the mask plate.

[0097] One of the above technical solutions has the following unexpected technical effects:

[0098] In the process of optical proximity correction, the minimum size rule value of the mask plate needs to be introduced to limit the distance between adjacent lithography patterns along the first direction. Due to the introduction of the limiting distance, the simulation profile of the lithography pattern cannot converge to the target pattern, therefore, the first side and the second side of the rectangular target pattern are moved along the second direction according to the edge difference between the simulation profile and the target pattern to widen or narrow the target pattern to obtain a reference pattern, the first side and the second side of the reference pattern are segmented, so that the number of movable sides of the reference pattern is greater than the number of movable sides of the rectangle, the degree of freedom of optical proximity correction is increased, the reference pattern is taken as the target to perform optical proximity correction, and the condition of the limiting distance is superimposed, so that the simulation profile of the updated lithography pattern can converge to the target pattern, the convergence degree and the accuracy of the target pattern can be improved while ensuring that the lithography pattern meets the minimum size rule value of the mask plate, the accuracy of lithography is ensured, and the performance of the product is further ensured.

[0099] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by a computer program instructing related hardware, and the computer program can be stored in a non-volatile computer readable storage medium. When the computer program is executed, the processes of the above-mentioned embodiments can be included. Any reference to a memory, a database or other medium used in the embodiments provided in the present application can include at least one of a non-volatile and a volatile memory.

[0100] In the light of the above, the embodiments according to the present disclosure are not described in detail with all the details necessary for the understanding of the principles of the present disclosure, and are not limited to the specific embodiments described. Obviously, many modifications and variations are possible in light of the above teachings. The embodiments are selected and described in order to better explain the principles of and practical application of the present disclosure, so that those skilled in the art can well utilize the present disclosure and make modifications and variations on the basis of the present disclosure. The scope of protection of the present disclosure should be defined by the scope of the claims of the present disclosure and their equivalents.

Claims

1. A method for pattern correction of a photomask, characterized in that, include: A target pattern is obtained, wherein the target pattern is square. Along a first direction, the photolithographic patterns of adjacent target patterns are subject to a restricted distance, and the distance between the simulated outline of the pattern and the boundary of the target pattern in this direction exceeds a preset distance threshold. Along a second direction, the photolithographic patterns of adjacent target patterns are not subject to a restricted distance, and the distance between the simulated outline of the pattern and the boundary of the target pattern in this direction exceeds a preset distance threshold. The first direction is perpendicular to the second direction. According to the distance between the simulated outline of the pattern and the boundary of the target pattern, the target pattern is narrowed along the second direction to obtain a rectangular reference pattern. The reference pattern includes a first side, a second side, a third side, and a fourth side. Along the second direction, the first side is opposite to the second side, and along the first direction, the third side is opposite to the fourth side. The first side and the second side are divided into multiple sub-sides, and four reference evaluation points are set on the reference pattern, including setting a single reference evaluation point at the midpoint of the divided first side and the second side, and setting a single reference evaluation point at the midpoint of the third side and the fourth side. Optical proximity correction is performed on the reference pattern to update the lithographic pattern and the pattern simulation contour. Along the first direction, the distance between adjacent updated lithographic patterns is limited. Along the first direction and the second direction, determine whether the interval distance from the updated pattern simulation contour to the boundary of the target pattern is less than a preset distance threshold. If the determination result is yes, output the updated lithography pattern. as well as If the determination result is negative, return to the step of obtaining the reference pattern. In the step of performing optical proximity correction on the reference pattern, the multi-segment sub-edges, the third edge, and the fourth edge are all movable edges. The photomask is used to form the hole layer of the semiconductor device.

2. The pattern correction method according to claim 1, characterized in that, In the step of optical proximity correction of the reference pattern, the reference pattern is optically corrected based on the four reference evaluation points so that the correction result converges to the four target evaluation points at the midpoints of the four sides of the target pattern.

3. The pattern correction method according to claim 1, characterized in that, The steps of splitting the first edge and the second edge to obtain multiple edge segments include: The first edge is split to obtain the first sub-edge and the second sub-edge; and The second edge is split to obtain the third and fourth sub-edges.

4. The pattern correction method according to claim 3, characterized in that, In the step of dividing the first edge and the second edge to obtain multiple sub-edges, the first edge and the second edge are divided equally.

5. The pattern correction method according to any one of claims 1 to 4, characterized in that, Also includes: Obtain the distribution map of multiple target graphics; Optical proximity correction is performed on the plurality of target patterns to obtain the photolithographic patterns of the plurality of target patterns, wherein the photolithographic patterns of adjacent target patterns are subject to a limited distance; as well as The simulated outline of the graphic is obtained based on the photolithographic pattern of the target graphic. Specifically, the target pattern is selected based on the result of determining whether the simulated outline of the graphic converges to the target graphic.

6. A pattern correction system for a photomask, characterized in that, include: A target pattern acquisition module is used to acquire a target pattern, wherein the target pattern is a square. Along a first direction, the photolithographic patterns of adjacent target patterns are subject to a limited distance, and the distance between the simulated outline of the pattern and the boundary of the target pattern in this direction exceeds a preset distance threshold. Along a second direction, the photolithographic patterns of adjacent target patterns are not subject to a limited distance, and the distance between the simulated outline of the pattern and the boundary of the target pattern in this direction exceeds a preset distance threshold. The first direction is perpendicular to the second direction. A reference pattern acquisition module is used to narrow the target pattern along the second direction based on the interval distance between the pattern simulation outline and the boundary of the target pattern to obtain a rectangular reference pattern. The reference pattern includes a first side, a second side, a third side, and a fourth side. Along the second direction, the first side is opposite to the second side, and along the first direction, the third side is opposite to the fourth side. The segmentation module is used to segment the first side and the second side into multiple sub-segments and set four reference evaluation points on the reference pattern, including setting a single reference evaluation point at the midpoint of the segmented first side and the second side, and setting a single reference evaluation point at the midpoint of the third side and the fourth side. An optical proximity correction module is used to perform optical proximity correction on the reference pattern to update the lithographic pattern and the pattern simulation contour. Along the first direction, the distance between adjacent updated lithographic patterns is limited. The judgment module is used to determine whether the distance between the updated pattern simulation contour and the boundary of the target pattern is less than a preset distance threshold along the first direction and the second direction, respectively. If the judgment result is yes, the updated lithography pattern is output. If the determination result is negative, return to the step of obtaining the reference pattern in the reference pattern acquisition module. In the step of performing optical proximity correction on the reference pattern, the multi-segment sub-edges, the third edge, and the fourth edge are all movable edges. The photomask is used to form the hole layer of the semiconductor device.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 5.

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