Pattern correction method and system of mask plate and medium

Abstract

The invention provides a mask plate pattern correction method, and relates to the field of semiconductor manufacturing, and the method comprises the steps: obtaining a square target pattern, limiting photoetching patterns of adjacent target patterns in a first direction by a limiting distance, and not limiting the distance between adjacent photoetching patterns in a second direction by the limiting distance; the distance between the simulated contour and the boundary of the target pattern in the first and second directions exceeds a preset distance threshold; widening or narrowing the target pattern along a second direction according to the spacing distance to obtain a reference pattern; respectively segmenting two opposite edges of the reference pattern along the second direction to obtain a plurality of sub-edges; optical proximity correction is carried out on the reference pattern, the photoetching pattern and the pattern simulation contour are updated, and the multiple segments of sub-edges and the undivided edges of the reference pattern are all movable edges; and judging whether the spacing distance from the updated pattern simulation contour to the boundary of the target pattern is smaller than a preset distance threshold, and if so, outputting the updated photoetching pattern. The method enables the simulated contour of the updated photolithographic pattern to converge to the target pattern.

Description

Technical Field

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

[0002] Photolithography is an important process in the semiconductor device manufacturing process; photolithography is the process of transferring the pattern on the photomask to the photoresist layer by exposure and development. However, in the photolithography process, when the pattern on the mask is transferred to the photoresist layer through exposure and development, due to the imperfection of the optical system and the diffraction effect, the pattern on the photoresist layer and the pattern on the photomask will deviate, which will affect the performance of the product when the product is formed based on the pattern on the photoresist.

[0003] Optical Proximity Correction (OPC) is a lithography enhancement technology used in the semiconductor manufacturing process. Its main purpose is to correct the distortion of lithography patterns caused by diffraction effects and other optical effects to ensure that the circuit pattern on the wafer is as consistent as possible with the original design. In the actual production process, after the OPC step, a manufacturability rule check (Mask Rule Constraints, MRC) is required to ensure that the pattern is suitable for the mask preparation process. These rules usually include the minimum line width (min Width) and line spacing (min Space) of the pattern, as well as the minimum spacing (corner-to-corner) between the corners of the pattern. However, the introduction of MRC will have a greater impact on the convergence of OPC, affect the accuracy of the correction, and result in larger errors, thereby affecting the performance of the product. Summary of the invention

[0004] In view of the above problems, a new mask pattern correction method and system and medium thereof need to be proposed.

[0005] According to a first aspect of the present disclosure, a method for correcting a pattern of a mask is provided, comprising: Acquire a target pattern, the target pattern is a square, along a first direction, photolithography patterns adjacent to the target pattern are subject to a restricted distance, and a distance between a pattern simulation contour and a boundary of the target pattern in this direction exceeds a preset distance threshold; along a second direction, photolithography patterns adjacent to the target pattern are not subject to a restricted distance, and a distance between the pattern simulation contour and the boundary of the target pattern in this direction exceeds a preset distance threshold, and the first direction is perpendicular to the second direction; widening or narrowing the target pattern along the second direction according to the spacing distance between the pattern simulation outline and the boundary of the target pattern to obtain a rectangular reference pattern, wherein the reference pattern includes a first side, a second side, a third side and a fourth side, wherein the first side is opposite to the second side along the second direction, and the third side is opposite to the fourth side along the first direction; Splitting the first edge and the second edge respectively to obtain a plurality of sub-edges; Performing optical proximity correction on the reference pattern to update the photolithography pattern and the pattern simulation profile, wherein adjacent updated photolithography patterns are limited by a limited distance along the first direction; Determine along the first direction and the second direction whether the interval distance between the updated pattern simulation contour and the target pattern boundary is less than a preset distance threshold, and if the determination result is yes, output the updated lithography pattern; and If the judgment result is no, return to the step of obtaining the reference pattern, Wherein, in the step of performing optical proximity correction on the reference pattern, the multiple sub-edges, the third edge and the fourth edge are all movable edges.

[0006] Optionally, the method further includes setting evaluation points at midpoints of the first side, the second side, the third side and the fourth side. Wherein, in the step of performing optical proximity correction on the reference pattern, optical proximity correction is performed on the reference pattern according to the evaluation point.

[0007] Optionally, in the step of obtaining a reference pattern: When the pattern simulation contour is inside the edge of the target pattern along the second direction, widening the target pattern according to the spacing distance, When the pattern simulation outline is outside the edge of the target pattern along the second direction, the target pattern is narrowed according to the spacing distance.

[0008] Optionally, the step of respectively dividing the first edge and the second edge to obtain a plurality of sub-edges includes: Splitting the first edge to obtain a first sub-edge and a second sub-edge; and The second edge is split to obtain a third sub-edge and a fourth sub-edge.

[0009] Optionally, in the step of dividing the first edge and the second edge to obtain a plurality of sub-edges, the first edge and the second edge are divided equally.

[0010] Optionally, it also includes: Obtain distribution graphs of multiple target graphics; Performing optical proximity correction on the plurality of target patterns to obtain photolithography patterns of the plurality of target patterns, wherein the photolithography patterns of adjacent target patterns are limited by a limited distance; and Obtaining a graphic simulation profile according to the photolithographic pattern of the target graphic, The target pattern is selected according to the result of judging whether the graphic simulation profile converges to the target graphic.

[0011] Optionally, the mask is used to form a hole layer of a semiconductor device.

[0012] According to a second aspect of the present disclosure, a mask pattern correction system is provided, comprising: A target pattern acquisition module is used to acquire a target pattern, wherein the target pattern is a square, and along a first direction, photolithography patterns adjacent to the target pattern are subject to a limited distance restriction, and a distance between a pattern simulation contour and a boundary of the target pattern in this direction exceeds a preset distance threshold; along a second direction, photolithography patterns adjacent to the target pattern are not subject to a limited distance restriction, and a distance between the pattern simulation contour and the boundary of the target pattern in this direction exceeds a preset distance threshold, and the first direction is perpendicular to the second direction; a reference pattern acquisition module, configured to widen or narrow the target pattern along the second direction according to the spacing distance between the pattern simulation outline and the boundary of the target pattern, so as to obtain a rectangular reference pattern, wherein the reference pattern comprises a first side, a second side, a third side and a fourth side, wherein 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; A segmentation module, used for segmenting the first edge and the second edge to obtain multiple sub-edges; An optical proximity correction module, configured to perform optical proximity correction on the reference pattern to update the photolithography pattern and the pattern simulation profile, wherein adjacent updated photolithography patterns are limited by a limited distance along the first direction; a judgment module, configured to judge whether the interval 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, 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 acquisition module if the judgment result is no. Wherein, in the step of performing optical proximity correction on the reference pattern, the multiple sub-edges, the third edge and the fourth edge are all movable edges.

[0013] According to a third aspect of the present disclosure, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the method described above are implemented.

[0014] One of the above technical solutions has the following unexpected technical effects: In the process of optical proximity correction, it is necessary to introduce the limitation of the minimum size rule value of the mask to ensure that the distance between adjacent lithography patterns along the first direction is not less than the limit distance. Due to the introduction of the limit distance, the simulated contour of the lithography pattern cannot converge to the target pattern. Therefore, the first side and the second side of the square target pattern are moved along the second direction according to the distance between the simulated contour 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 4 movable sides of the rectangle, which increases the degree of freedom of optical proximity correction. The reference pattern is used as the target for optical proximity correction, and the condition of the limit distance is superimposed so that the simulated contour of the updated lithography pattern can converge to the target pattern. While ensuring that the lithography pattern meets the minimum size rule value of the mask, 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 guaranteed.

[0015] It should be noted that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other objects, features and advantages of the present application will become more apparent through the following description of the embodiments of the present application with reference to the accompanying drawings, in which: Figure 1 A schematic diagram of a pattern after an optical proximity correction step in the related art is shown; Figure 2 A schematic diagram of a pattern after an optical proximity correction step in the related art is shown; Figure 3 A schematic diagram of a pattern after the minimum size rule value limitation is introduced in the related art is shown; Figure 4 Shows Figure 3 A schematic diagram of the enlarged structure of the target graphic and the graphic simulation outline; Figure 5 A schematic diagram showing the steps of a method for correcting a pattern of a mask according to an embodiment of the present disclosure is shown; Figure 6 A graphical schematic diagram showing an embodiment of the present disclosure after an optical proximity correction step; Figure 7 A schematic diagram showing a reference pattern of an embodiment of the present disclosure; Figure 8 A schematic diagram showing edge segmentation of a reference pattern according to an embodiment of the present disclosure is shown; Fig. 9 A schematic diagram showing the setting of evaluation points in an embodiment of the present disclosure is shown; Fig.10 A schematic diagram showing a photolithographic pattern of a target pattern according to an embodiment of the present disclosure; Fig.11 A schematic diagram showing that the updated pattern simulation profile of the embodiment of the present disclosure converges to the target pattern; Fig.12 A schematic structural diagram of a pattern correction system for a mask according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0017] The present application will be described in more detail below with reference to the accompanying drawings. In each of the accompanying drawings, the same elements are represented by similar reference numerals. For the sake of clarity, the various parts in the accompanying drawings are not drawn to scale. In addition, some well-known parts may not be shown.

[0018] Many specific details of the present disclosure are described below, such as device structure, materials, dimensions, processing technology and techniques, so as to more clearly understand the present disclosure. However, as those skilled in the art will appreciate, the present disclosure may not be implemented in accordance with these specific details.

[0019] At the same time, certain words are used in this patent specification and claims to refer to specific components. It should be understood by those skilled in the art that hardware manufacturers may use different terms to refer to the same component. This patent specification and claims do not use differences in names as a way to distinguish components, but rather use differences in components' functions as the criteria for distinction.

[0020] In addition, it should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the statement "comprise one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.

[0021] This application may be presented in a variety of forms, some examples of which are described below.

[0022] Figure 1 and Figure 2 A schematic diagram of a pattern after an optical proximity correction step in the related art is shown.

[0023] In the related art, when it is necessary to make a hole layer in a chip, a mask of the hole layer is needed. The hole layer includes a contact hole (CT) layer and a via (Via) layer. The contact hole CT is a hole used to connect the metal wire and the transistor, and the via is a hole used to connect different metal layers. In the manufacturing process of integrated circuits, model-based optical proximity correction (Model-based Optical Proximity Correction) has been widely used since the 90nm technology node. See Figure 1 The target graphic 10 is a square, and evaluation points 11 are set at the midpoints of the four sides of the target graphic 10. If the four sides of the target graphic 10 are segmented respectively, 8 movable sides are obtained, and then the target graphic 10 is subjected to OPC to obtain a photolithography pattern (or mask pattern) 12 of the target graphic 10. Then, a graphic simulation contour 13 is obtained based on the photolithography pattern 12. However, the interval distance between the graphic simulation contour 13 and the evaluation point 11 exceeds a preset distance threshold, and at this time, the graphic simulation contour 13 does not converge to the target graphic 10.

[0024] See also Figure 2 Based on the consideration of convergence, when making the mask template of the hole layer, the four edges of the target graphic 10 are generally not segmented separately. Therefore, in the OPC process, the four edges can only be moved as a whole, and iterative calculation is continuously performed until the graphic simulation contour 13 converges to the target graphic 10, and the final lithography pattern 12 is a rectangle.

[0025] Figure 3 The figure shows a schematic diagram of a pattern after the minimum size rule value limitation is introduced in the related art. Figure 4 Shows Figure 3 Schematic diagram of the enlarged structure of the target graphic and the graphic simulation outline.

[0026] See also Figure 3 , with the advancement of technology nodes, the layout complexity and density of the hole layer are gradually increasing. For example, along the X-axis direction, the distance between two adjacent target graphics 10 is getting closer and closer. However, after the introduction of MRC, the OPC correction process will be limited by MRC. For example, along the X-axis direction, the distance between two adjacent photolithography patterns 12 cannot be less than the limit distance D. After OPC, the graphic simulation profile 13 calculated based on the photolithography pattern 12 does not converge to the target graphic 10.

[0027] See also Figure 4 , along the X-axis direction, the size of the graphic simulation outline 13 is too small, and along the Y-axis direction, the size of the graphic simulation outline 13 is too large. Specifically, the distance difference between the graphic simulation outline 13 and the evaluation point 11 on the upper edge of the target graphic 10 is d1, the distance difference between the graphic simulation outline 13 and the evaluation point 11 on the lower edge of the target graphic 10 is d2, the distance difference between the graphic simulation outline 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 outline 13 and the evaluation point 11 on the right edge of the target graphic 10 is d4. In some examples, if the graphic simulation profile 13 is located outside the edge of the target graphic 10, the distance difference is positive, and if the graphic simulation profile 13 is located inside the edge of the target graphic 10, the distance difference is negative, wherein d1 is 2.9nm, d2 is 2.9nm, d3 is -1.4nm, and d4 is -2.4nm. Therefore, along the X-axis direction, the interval between the graphic simulation profile 13 and the boundary of the target graphic 10 is -3.8nm, and along the Y-axis direction, the interval between the graphic simulation profile 13 and the boundary of the target graphic 10 is 5.8nm. However, along the X-axis and the Y-axis, the interval from the graphic simulation profile 13 to the boundary of the target graphic 10 cannot exceed the preset distance threshold. The preset distance thresholds of the two axes can be the same or different. Assuming that the preset distance thresholds of the two axes are both 1nm, in this example, the interval distance exceeds 1nm whether along the X-axis direction or the Y-axis direction. This non-convergence situation will result in the contact area with the conductive material of the hole layer in the semiconductor device not meeting the requirements, and ultimately affecting the yield of the product. There are currently two ways to solve this problem: first, lower the MRC standard, and second, use inverse lithography technology (ILT) to seek better optical solutions. However, these methods are not only time-consuming but also costly. Therefore, a simple, efficient and low-cost method is urgently needed to solve this problem.

[0028] In view of the above problems, the present disclosure proposes a new mask pattern correction method and system.

[0029] Figure 5 A schematic diagram showing the steps of a method for correcting a pattern of a mask according to an embodiment of the present disclosure is shown.

[0030] See also Figure 5 The pattern correction method of the mask of the embodiment of the present disclosure includes: In step S01, a target pattern is obtained. The target pattern is a square, and along a first direction, the photolithography patterns of adjacent target patterns are subject to a limited distance, and the spacing between the pattern simulation contour and the boundary of the target pattern in this direction exceeds a preset distance threshold; along a second direction, the photolithography patterns of adjacent target patterns are not subject to a limited distance, and the spacing between the pattern simulation contour and the boundary of the target pattern in this direction exceeds a preset distance threshold, the first direction is perpendicular to the second direction, the first direction may be one of the X-axis direction and the Y-axis direction, and the second direction may be the other of the X-axis direction and the Y-axis direction.

[0031] In step S02, a reference pattern is obtained, wherein along the second direction, the target pattern is widened or narrowed according to the spacing distance between the pattern simulation contour and the boundary of the target pattern to obtain a rectangular reference pattern, the reference pattern comprising 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.

[0032] In step S03, the edge of the reference pattern is segmented, wherein the first edge and the second edge are segmented respectively to obtain a plurality of sub-edges.

[0033] In step S04, optical proximity correction is performed on the reference pattern, wherein the photolithography pattern and the pattern simulation profile can be updated after the correction, and adjacent updated photolithography patterns are limited by a limited distance along the first direction.

[0034] In step S05, it is determined whether the target pattern simulation contour converges to the target pattern. In the first direction and the second direction, it is determined whether the interval distance between the updated pattern simulation contour and the target pattern boundary is less than a preset distance threshold. If the determination result is yes, step S06 is performed to output the updated lithography pattern. If the determination result is no, the process returns to step S02.

[0035] The following will be combined Figures 6 to 11 The steps of the pattern correction method of the mask plate according to the embodiment of the present disclosure are described in detail.

[0036] Figure 6 FIG. 4 shows a graphical diagram of an embodiment of the present disclosure after an optical proximity correction step, wherein: Figure 6 Only a portion of the target pattern and photolithography pattern is shown.

[0037] See also Figure 6, firstly, a target pattern distribution diagram of the hole layer is obtained, wherein, along the X-axis direction, the distance between adjacent first target patterns 111 is L1, and the distance between adjacent second target patterns 112 is L2, wherein L2 is greater than L1, and L1 is, for example, the minimum size (min.rule) of the design spacing between adjacent target patterns. In this embodiment, the first target pattern 111 and the second target pattern 112 are both square. Optical proximity correction is performed on each target pattern respectively to obtain photolithography patterns of multiple target patterns, including a first photolithography pattern 121 and a second photolithography pattern 122, wherein the distance between the photolithography patterns of adjacent target patterns is not less than the limit distance D. Since L2 is large, the limit distance D has little effect on the optical proximity correction here, and the graphic simulation profile 131 calculated according to the first photolithography pattern 121 converges to the first target pattern 111. However, the value of L1 is too small, and the limit distance D has a large effect on the optical proximity correction here, and the graphic simulation profile 132 calculated according to the second photolithography pattern 122 cannot converge to the second target pattern 112. According to the result of judging whether the graphic simulation contour converges to the target graphic, the non-convergent target graphic is selected as the target pattern. In this embodiment, the second target graphic 112 is the target pattern, and correspondingly, the graphic simulation contour 132 is the pattern simulation contour of the target pattern. The interval distance between the graphic simulation contour 132 and the boundary of the second target graphic 112 exceeds the preset distance threshold. For the description of the interval distance and the preset distance threshold, please refer to the description of Figure 4 Description. It should be noted that, in the present embodiment, along the Y-axis direction, the design spacing between the adjacent first target graphics 111 and the second target graphics 112 is greater than the minimum size (min.rule), and after the optical proximity correction, the distance between the photolithography patterns along the Y-axis direction is also greater than the limit distance D, so it can be regarded as that the distance between the adjacent photolithography patterns along the Y-axis direction is not limited by the limit distance D. While along the X-axis direction, the distance between the photolithography patterns cannot be further narrowed, so it can be regarded as that the distance between the adjacent photolithography patterns along the X-axis direction is limited by the limit distance D. In addition, if the design spacing between the adjacent target graphics along the X-axis and Y-axis directions is the minimum size (min.rule), after the optical proximity correction, the distance between the photolithography patterns along the X-axis and Y-axis directions is limited by the limit distance D, the problem of non-convergence of the edge profile will not occur, and the specific values ​​of the minimum size (min.rule) and the limit distance D along the X-axis and Y-axis directions can be the same or different, and those skilled in the art can set them as needed.

[0038] Figure 7 A schematic diagram showing a reference pattern according to an embodiment of the present disclosure.

[0039] See also Figure 7Since the graphic simulation outline 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 spacing distance (the size of the distance that the graphic simulation outline 132 exceeds the outside of the edge), thereby obtaining a 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. Among them, the first side L10 and the second side L20 are long sides, and along the Y-axis direction, the first side L10 and the second side L20 are opposite; the third side L30 and the fourth side L40 are short sides, and along the X-axis direction, the third side L30 and the fourth side L40 are opposite.

[0040] 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 spacing distance (the size of the distance that the graphic simulation contour 132 is less than the inside of the edge), thereby obtaining a reference pattern 140.

[0041] Figure 8 A schematic diagram showing edge segments of a reference pattern according to an embodiment of the present disclosure is shown.

[0042] See also Figure 8 , respectively divide the first side L10 and the second side L20 to obtain multiple sub-sides. In this embodiment, the first side L10 is evenly divided to obtain the first sub-side L11 and the second sub-side L12, and the second side L20 is evenly divided to obtain the third sub-side L21 and the 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.

[0043] Fig. 9 A schematic diagram showing the setting of evaluation points according to an embodiment of the present disclosure is shown.

[0044] See also Fig. 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 evenly divided into the first sub-side L11 and the second sub-side L12, and the second side L20 has been evenly divided into the third sub-side L21 and the fourth sub-side L22, in theory, an evaluation point should be set at the midpoint of each free side. However, in order to make the final pattern simulation contour a circle, the number of evaluation points needs to be set to 4, so as to determine 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.

[0045] In addition, four evaluation points 110 (target evaluation points) are also set on the second target graphic 112, which are respectively located at the midpoints of the four sides of the square. 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 contour converges to the target pattern in subsequent steps.

[0046] Fig.10 A schematic diagram showing a photolithographic pattern of a target pattern according to an embodiment of the present disclosure.

[0047] See also Fig.10 , the reference pattern 140 is optically proximity corrected according to the evaluation points 141 on each side of the reference pattern 140, thereby obtaining an updated photolithography 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 OPC, the updated photolithography pattern 150 is hexagonal and has a T-shaped structure.

[0048] Fig.11 A schematic diagram showing that the updated pattern simulation profile according to an embodiment of the present disclosure converges to the target pattern.

[0049] OPC correction is performed with reference evaluation point 141 as the target. In theory, the updated pattern simulation contour should pass through or be closer to reference evaluation point 141, thereby converging to reference pattern 140. However, due to the introduction of the MRC rule, adjacent updated lithography patterns 150 are limited by a limited distance D along the X-axis direction, that is, the limited distance D limits the OPC correction. Therefore, along the Y-axis direction, after narrowing the second target graphic 112 to obtain the reference pattern 140, the updated pattern simulation contour will be located outside the edge of the reference pattern 140, falling to or closer to the target evaluation point 110, thereby converging to the second target graphic 112.

[0050] Further, it is determined whether the interval distance between the updated pattern simulation contour and the boundary of the second target pattern 112 is less than the preset distance threshold. If the determination result is yes, the updated lithography pattern 150 is output. If the determination result is no, the process returns to the step of obtaining the reference pattern 140, and the widening or narrowing distance of the second target pattern 112 is readjusted according to the updated interval distance. By continuously adjusting the widening or narrowing distance, dividing the edge and the OPC correction, the non-convergent pattern is finally converged.

[0051] In this embodiment, it is necessary to first determine that the limiting direction of the MRC rule (usually the min.rule direction) is the X-axis direction, and then widen or narrow the target pattern in the Y direction perpendicular to the X-axis direction to obtain a reference pattern. When the distance between the updated pattern simulation contour 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 improve. For example, in this embodiment, along the X-axis direction, the distance between the final pattern simulation contour and the boundary of the target pattern is -0.6nm, and along the Y-axis direction, the distance between the final pattern simulation contour and the boundary of the target pattern is 0.4nm. Compare Figure 4 The spacing distance is (3.8-0.6) / 3.8>84.2%, (5.8-0.4) / 5.8>93.1%, so relative to Figure 4 In this embodiment, 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%.

[0052] Fig.12 A schematic structural diagram of a pattern correction system for a mask according to an embodiment of the present disclosure is shown.

[0053] See also Fig.12 The pattern correction system of the mask template of the embodiment of the present 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.

[0054] The target pattern acquisition module 210 is used to acquire a target pattern, which is a square. Along a first direction, the photolithography patterns of adjacent target patterns are subject to a restricted distance limit, and the spacing between the pattern simulation contour and the boundary of the target pattern in this direction exceeds a preset distance threshold. Along a second direction, the photolithography patterns of adjacent target patterns are not subject to a restricted distance limit, and the spacing between the pattern simulation contour and the boundary of the target pattern in this direction exceeds the preset distance threshold, and the first direction is perpendicular to the second direction.

[0055] The reference pattern acquisition module 220 is used to widen or narrow the target pattern along the second direction according to the spacing distance between the pattern simulation outline and the boundary of the target pattern to obtain a rectangular reference pattern, wherein the reference pattern includes a first side, a second side, a third side and a fourth side, wherein the first side is opposite to the second side along the second direction, and the third side is opposite to the fourth side along the first direction.

[0056] The segmentation module 230 is used to segment the first edge and the second edge to obtain multiple sub-edges; 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. Along the first direction, adjacent updated photolithography patterns are limited by a limited distance.

[0057] The judgment module 250 is used to judge whether the interval distance from the updated pattern simulation contour to 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 judgment result is no, the reference pattern acquisition module is returned to the step of obtaining the reference pattern.

[0058] The pattern correction system of the mask plate of the embodiment of the present disclosure can use the pattern correction method of the mask plate of the embodiment of the present disclosure to correct the pattern of the mask plate, and the mask plate is, for example, a mask plate for a hole layer in a semiconductor manufacturing process.

[0059] The embodiment of the present disclosure further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the method for correcting a pattern of a mask as described above are implemented.

[0060] One of the above technical solutions has the following unexpected technical effects: In the process of optical proximity correction, it is necessary to introduce the limitation of the minimum size rule value of the mask to ensure that the adjacent photolithography patterns are limited by the limited distance along the first direction. Due to the introduction of the limited distance, the simulated contour of the photolithography 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 simulated contour 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 4 movable sides of the rectangle, which increases the degree of freedom of optical proximity correction. The reference pattern is used as the target for optical proximity correction, and the condition of the limited distance is superimposed so that the simulated contour of the updated photolithography pattern can converge to the target pattern. While ensuring that the photolithography pattern meets the minimum size rule value of the mask, 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 guaranteed.

[0061] A person skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to a memory, a database or other medium used in the embodiments provided in this application can include at least one of a non-volatile and a volatile memory.

[0062] According to the embodiments of the present disclosure as above, these embodiments do not describe all the details in detail, nor do they limit the invention to specific embodiments. Obviously, many modifications and changes can be made based on the above description. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present disclosure, so that those skilled in the art can make good use of the present disclosure and the modifications based on the present disclosure. The scope of protection of the present disclosure shall be based on the scope defined by the claims of the present disclosure and their equivalents.

Claims

1. A method for correcting a pattern of a mask, characterized in that: include: Acquire a target pattern, the target pattern is a square, along a first direction, photolithography patterns adjacent to the target pattern are subject to a restricted distance, and a distance between a pattern simulation contour and a boundary of the target pattern in this direction exceeds a preset distance threshold; along a second direction, photolithography patterns adjacent to the target pattern are not subject to a restricted distance, and a distance between the pattern simulation contour and the boundary of the target pattern in this direction exceeds a preset distance threshold, and the first direction is perpendicular to the second direction; widening or narrowing the target pattern along the second direction according to the spacing distance between the pattern simulation outline and the boundary of the target pattern to obtain a rectangular reference pattern, wherein the reference pattern includes a first side, a second side, a third side and a fourth side, wherein the first side is opposite to the second side along the second direction, and the third side is opposite to the fourth side along the first direction; Splitting the first edge and the second edge respectively to obtain a plurality of sub-edges; Performing optical proximity correction on the reference pattern to update the photolithography pattern and the pattern simulation profile, wherein adjacent updated photolithography patterns are limited by a limited distance along the first direction; Along the first direction and the second direction, respectively determine whether the interval distance between the updated pattern simulation contour and the target pattern boundary is less than a preset distance threshold, and if the determination result is yes, output the updated lithography pattern; as well as If the judgment result is no, return to the step of obtaining the reference pattern, Wherein, in the step of performing optical proximity correction on the reference pattern, the multiple sub-edges, the third edge and the fourth edge are all movable edges.

2. The pattern correction method according to claim 1, characterized in that: The method further includes setting evaluation points at midpoints of the first side, the second side, the third side, and the fourth side, Wherein, in the step of performing optical proximity correction on the reference pattern, optical proximity correction is performed on the reference pattern according to the evaluation point.

3. The pattern correction method according to claim 1, characterized in that: In the step of obtaining a reference pattern: When the pattern simulation contour is inside the edge of the target pattern along the second direction, widening the target pattern according to the spacing distance, When the pattern simulation outline is outside the edge of the target pattern along the second direction, the target pattern is narrowed according to the spacing distance.

4. The pattern correction method according to claim 1, characterized in that: The step of respectively dividing the first edge and the second edge to obtain a plurality of sub-edges comprises: Splitting the first edge to obtain a first sub-edge and a second sub-edge; and The second edge is split to obtain a third sub-edge and a fourth sub-edge.

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

6. The pattern correction method according to any one of claims 1 to 5, characterized in that: Also includes: Obtain distribution graphs of multiple target graphics; Performing optical proximity correction on the plurality of target graphics to obtain photolithography patterns of the plurality of target graphics, wherein the photolithography patterns of adjacent target graphics are limited by a limited distance; as well as Obtaining a graphic simulation profile according to the photolithographic pattern of the target graphic, The target pattern is selected according to the result of judging whether the graphic simulation profile converges to the target graphic.

7. The pattern correction method according to any one of claims 1 to 5, characterized in that: The mask is used to form a hole layer of a semiconductor device.

8. A mask pattern correction system, characterized in that: include: A target pattern acquisition module is used to acquire a target pattern, wherein the target pattern is a square, and along a first direction, photolithography patterns adjacent to the target pattern are subject to a limited distance restriction, and a distance between a pattern simulation contour and a boundary of the target pattern in this direction exceeds a preset distance threshold; along a second direction, photolithography patterns adjacent to the target pattern are not subject to a limited distance restriction, and a distance between the pattern simulation contour and the boundary of the target pattern in this direction exceeds a preset distance threshold, and the first direction is perpendicular to the second direction; a reference pattern acquisition module, configured to widen or narrow the target pattern along the second direction according to the spacing distance between the pattern simulation outline and the boundary of the target pattern, so as to obtain a rectangular reference pattern, wherein the reference pattern comprises a first side, a second side, a third side and a fourth side, wherein 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; A segmentation module, used for segmenting the first edge and the second edge to obtain multiple sub-edges; An optical proximity correction module, configured to perform optical proximity correction on the reference pattern to update the photolithography pattern and the pattern simulation profile, wherein adjacent updated photolithography patterns are limited by a limited distance along the first direction; A judging module, configured to judge whether the interval 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, and output the updated lithography pattern if the judgment result is yes; If the judgment result is no, return to the step of obtaining the reference pattern in the reference pattern acquisition module, Wherein, in the step of performing optical proximity correction on the reference pattern, the multiple sub-edges, the third edge and the fourth edge are all movable edges.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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