Optical proximity correction method and system, mask, apparatus, and storage medium

Abstract

An optical proximity correction method and system, a mask, a device and a storage medium, the correction method comprising: obtaining a design layout including a plurality of design patterns, the design layout being divided into a plurality of sub-regions; respectively performing optical proximity correction processing on the design patterns in each sub-region, the optical proximity correction processing on the design patterns in two adjacent sub-regions comprising: in the two adjacent sub-regions, taking any one sub-region as a first region and the other sub-region as a second region, forming a buffer region at the junction of the first region and the second region; performing optical proximity correction processing on the design patterns in the first region and the buffer region to obtain a first correction result; performing optical proximity correction processing on the design patterns in the second region to obtain a second correction result; and combining the first correction result and the second correction result to obtain a third correction result corresponding to the buffer region. The present application is beneficial to making the optical proximity correction processing more accurate.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing, and more particularly to an optical proximity correction method and system, a photomask, an apparatus, and a storage medium. Background Technology

[0002] To transfer a pattern from a photomask to the silicon wafer surface, a typical process involves exposure, development, and etching. However, as device dimensions shrink, the difference between the pattern on the chip surface and the original photomask pattern increases. To avoid inconsistencies between the pattern on the chip and the photomask pattern caused by optical proximity effect, the current solution is usually to perform optical proximity correction (OPC) on the photomask pattern before transferring the pattern. The OPC correction process typically includes a mask manufacturing rule check to ensure final pattern convergence and photomask fabrication accuracy.

[0003] However, since the area of ​​the map is often very large, it is difficult to perform OPC correction on the entire map at the same time. Therefore, it is necessary to divide the map into multiple sub-regions, perform OPC correction on each sub-region separately, and then stitch the processed sub-regions together to form the map.

[0004] However, partitioning the layout often causes some problems that affect the OPC correction results. Summary of the Invention

[0005] The problem solved by the embodiments of the present invention is to provide an optical proximity correction method and system, mask, device and storage medium to improve the correction accuracy of optical proximity correction.

[0006] To address the aforementioned problems, this invention provides an optical proximity correction method, comprising: acquiring a design layout, the design layout including multiple design graphics, the design layout being divided into multiple sub-regions, the multiple sub-regions being distributed in a matrix; performing optical proximity correction processing on the design graphics in each of the sub-regions respectively to obtain a target corrected graphic located in each of the sub-regions, wherein performing optical proximity correction processing on the design graphics in two adjacent sub-regions includes: in two adjacent sub-regions, taking one sub-region as a first region and the other sub-region as a second region, forming a buffer zone located in the second region at the boundary between the first region and the second region, and the remaining region in the second region excluding the buffer zone as a fixed region; performing optical proximity correction processing on the design graphics in the first region and the buffer zone to obtain a first correction result for the first region and the buffer zone; performing optical proximity correction processing on the design graphics in the second region to obtain a second correction result; and combining the first correction result and the second correction result to obtain a third correction result corresponding to the buffer zone.

[0007] Accordingly, this invention also provides an optical proximity correction system, comprising: a layout acquisition module for acquiring a design layout, the design layout including multiple design graphics, the design layout being divided into multiple sub-regions, the multiple sub-regions being distributed in a matrix; a correction module for performing optical proximity correction processing on the design graphics in each of the sub-regions respectively to obtain target corrected graphics located in each of the sub-regions, wherein performing optical proximity correction processing on the design graphics in two adjacent sub-regions includes: a region setting unit for forming a buffer zone in the second region at the boundary between the first region and the second region, with one sub-region as a first region and the other sub-region as a second region, the remaining region in the second region excluding the buffer zone being a fixed region; a first correction unit for performing optical proximity correction processing on the design graphics in the first region and the buffer zone to obtain a first correction result for the first region and the buffer zone; a second correction unit for performing optical proximity correction processing on the design graphics in the second region to obtain a second correction result; and a third correction unit for combining the first correction result and the second correction result to obtain a third correction result corresponding to the buffer zone.

[0008] Accordingly, embodiments of the present invention also provide a photomask, including a pattern obtained using the optical proximity correction method provided in embodiments of the present invention.

[0009] Accordingly, embodiments of the present invention also provide an apparatus including at least one memory and at least one processor, wherein the memory stores one or more computer instructions, and the one or more computer instructions are executed by the processor to implement the optical proximity correction method provided in embodiments of the present invention.

[0010] Accordingly, embodiments of the present invention also provide a storage medium storing one or more computer instructions, which are used to implement the optical proximity correction method provided in embodiments of the present invention.

[0011] Compared with the prior art, the technical solution of the embodiments of the present invention has the following advantages:

[0012] In the optical proximity correction method provided by this invention, in the step of performing optical proximity correction processing on the design graphics in two adjacent sub-regions, a third correction result corresponding to the buffer is obtained by combining the first correction result and the second correction result. In this invention, a buffer is formed at the junction of the first region and the second region, and the second corrected graphics formed in the buffer comprehensively consider the first correction result and the second correction result. Compared with the scheme of directly using the first corrected graphics formed based on the second correction result as the target corrected graphics in the buffer, this scheme comprehensively considers the first correction result and the second correction result, so that at the junction of the first region and the second region, there is a transitional second corrected graphics between the target corrected graphics of the first region and the target corrected graphics of the fixed region in the second region. This avoids the situation where the correction results at the junction of the first region and the second region are too different due to the difference in the correction environment caused by the optical proximity correction processing of the first region and the second region. Therefore, after the various sub-regions are stitched together, the situation where the edge placement error of the target corrected graphics at the junction of the first region and the second region is too large due to the large difference in the correction results at the junction of the first region and the second region is avoided as much as possible. This makes the optical proximity correction processing of the design graphics more accurate. Attached Figure Description

[0013] Figure 1 This is a flowchart of an optical proximity correction method;

[0014] Figures 2 to 3 This is a schematic diagram of the steps in an optical proximity correction method.

[0015] Figure 4 This is a flowchart of an embodiment of the optical proximity correction method of the present invention;

[0016] Figure 5This is a flowchart of an embodiment of the optical proximity correction method of the present invention, which involves performing optical proximity correction processing on the design graphics in two adjacent sub-regions in step S2.

[0017] Figures 6 to 11 This is a schematic diagram of each step in one embodiment of the optical proximity correction method of the present invention;

[0018] Figure 12 This is a functional block diagram of an embodiment of the optical proximity correction system of the present invention;

[0019] Figure 13 This is a functional block diagram of the correction module in one embodiment of the optical proximity correction system of the present invention;

[0020] Figure 14 This is a hardware structure diagram of an embodiment of the device provided by the present invention. Detailed Implementation

[0021] The accuracy of optical proximity correction currently needs improvement. This paper analyzes the reasons why the accuracy of optical proximity correction needs further improvement, using one such method as an example.

[0022] Figure 1 This is a flowchart of an optical proximity correction method. (Refer to reference.) Figures 2 to 3 The diagram shows the steps in the optical proximity correction method.

[0023] refer to Figure 2 Step s1: Obtain the design version Figure 10 Design version Figure 10 Includes multiple design graphics 11, design version Figure 10 It is divided into multiple sub-regions 21, and the multiple sub-regions 21 are distributed in a matrix.

[0024] Reference Figure 2 and reference Figure 3 , Figure 3 for Figure 2 A magnified view of the dashed frame in the middle. Step s2: Perform optical proximity correction processing on the design graphics 11 in each sub-region 21.

[0025] Continue to refer to Figure 2 and Figure 3 Step s3: After performing optical proximity correction processing on the design graphics 11 in each sub-region 21, the sub-regions 21 are spliced ​​together.

[0026] In the step of performing optical proximity correction processing on the design graphics 11 in each sub-region 21, since each adjacent sub-region 21 undergoes its own optical proximity correction processing, the design graphics 11 located in the two sub-regions 21 near the boundary between the two adjacent sub-regions 21 are prone to significant differences in correction results due to differences in the correction environment. For example, Figure 3 As shown, near the boundary between two adjacent sub-regions 21, taking the design graphic 11 in the right sub-region 21 as an example, according to the correction environment of the left sub-region 21, the correction result of the design graphic 11 is the first corrected graphic 12 (the outline of the first corrected graphic 12 is represented by a dotted line). According to the correction environment of the right sub-region 21 itself, the correction result of the design graphic 11 is the second corrected graphic 13 (the outline of the second corrected graphic 13 is represented by a solid line). The first corrected graphic 12 and the second corrected graphic 13 are quite different. Therefore, after splicing the various sub-regions 21 in the future, due to the large difference in the correction results at the boundary between two adjacent sub-regions 21, it is easy to cause the edge placement error of the corrected graphic at the boundary between two adjacent sub-regions 21 to be too large, which in turn leads to poor accuracy of the optical proximity correction processing of the design graphic 11.

[0027] To address the aforementioned technical problem, embodiments of the present invention provide an optical proximity correction method. (Reference) Figure 4 The flowchart of an embodiment of the optical proximity correction method of the present invention is shown below. Figure 5 The diagram shows a flowchart of an embodiment of optical proximity correction processing of design patterns in two adjacent sub-regions in step S2 of the optical proximity correction method of the present invention.

[0028] In this embodiment, the optical proximity correction method includes the following basic steps:

[0029] Step S1: Obtain the design layout, which includes multiple design graphics and is divided into multiple sub-regions, which are distributed in a matrix.

[0030] Step S2: Perform optical proximity correction processing on the design graphics in each sub-region to obtain the target corrected graphics in each sub-region;

[0031] The optical proximity correction process for the design graphics in two adjacent sub-regions includes: Step S21: In two adjacent sub-regions, one sub-region is taken as the first region and the other sub-region is taken as the second region. A buffer zone is formed at the junction of the first region and the second region in the second region. The remaining region in the second region other than the buffer zone is taken as the fixed region.

[0032] Step S22: Perform optical proximity correction processing on the design graphics in the first region and the buffer to obtain the first correction result of the first region and the buffer;

[0033] Step S23: Perform optical proximity correction processing on the design graphic in the second region to obtain the second correction result;

[0034] Step S24: Combine the first correction result and the second correction result to obtain the third correction result corresponding to the buffer.

[0035] In this embodiment of the invention, a buffer zone is formed at the boundary between the first region and the second region. The second corrected graphic formed in the buffer zone takes into account both the first and second correction results. Compared to the scheme where the first corrected graphic formed based on the second correction result is directly used as the target corrected graphic in the buffer zone, this scheme takes into account both the first and second correction results. This results in a transitional second corrected graphic between the target corrected graphic of the first region and the target corrected graphic of the fixed region in the second region at the boundary between the first and second regions. This avoids the situation where the correction results at the boundary between the first and second regions differ too much due to differences in the correction environment caused by the optical proximity correction processing performed separately by the first and second regions. As a result, after the various sub-regions are stitched together, the situation where the edge placement error of the target corrected graphic at the boundary between the first and second regions is too large due to the large difference in the correction results at the boundary is avoided as much as possible. This makes the optical proximity correction processing of the design graphic more accurate.

[0036] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0037] Figures 6 to 11 This is a schematic diagram of each step in one embodiment of the optical proximity correction method of the present invention.

[0038] Reference Figure 6 and Figure 7 Step S1: Obtain the design layout 100, which includes multiple design graphics 110. The design layout 100 is divided into multiple sub-regions 210, which are distributed in a matrix.

[0039] Design pattern 110 is the target pattern to be transferred onto the wafer. After optical proximity correction is performed on design pattern 110, the obtained pattern is used to make a mask, and then photolithography is performed on the mask to form the corresponding mask pattern on the wafer.

[0040] Since the area of ​​the design layout 100 is usually large, the design layout 100 is divided into multiple sub-regions 210. By performing optical proximity correction processing on each sub-region 210 separately, and then stitching the processed sub-regions 210 together, the optical proximity correction processing of the design layout 100 is realized. This helps to avoid the time-consuming process of optical proximity correction processing on a large area, thereby saving the processing time of the optical proximity correction processing.

[0041] refer to Figure 7 In this embodiment, each sub-region 210 is assigned its own corresponding correction priority.

[0042] Each sub-region 210 is assigned a corresponding correction priority. In the subsequent steps of optical proximity correction processing of the design pattern 110 in each sub-region 210, each sub-region 210 is corrected sequentially according to its corresponding correction priority. This helps to avoid correction oscillations at the boundaries of adjacent sub-regions 210 due to the combined influence of adjacent sub-regions 210 when all sub-regions 210 are corrected at the same time, thus making it difficult to obtain a definite correction result. This helps to reduce the probability of disordered correction results at the boundaries of adjacent sub-regions 210, and thus helps to obtain a more accurate optical proximity correction result.

[0043] As an example, see reference Figure 7 In this embodiment, the correction priority of sub-region 210 is set to four levels, which are identified as 0, 1, 2 and 3 respectively. The correction priority decreases from 0 to 3. The correction priorities of the four sub-regions 210 that intersect at the same point are set to 0, 1, 2 and 3 respectively.

[0044] In this embodiment, before performing optical proximity correction processing on the design pattern 110 in each sub-region 210, the method further includes: dividing the edges of the design pattern 110 in each sub-region 210 and forming multiple line segments (not shown) connected end to end along the outline of the design pattern 110.

[0045] In the subsequent optical proximity correction process of the design graphic 110, in order to reduce the arbitrariness of edge movement, the position of line segments is adjusted (e.g., line segments are translated) to reduce edge placement errors. In this embodiment, multiple line segments connected end to end are formed along the outline of the design graphic 110, and the position of the line segments is subsequently adjusted for optical proximity correction.

[0046] Reference Figures 8 to 11 Step S2 is executed to perform optical proximity correction processing on the design graphics 110 in each sub-region 210 to obtain the target corrected graphics located in each sub-region 210.

[0047] After optical proximity correction is performed on the design pattern 110, the obtained corrected pattern is used to make a mask, and then the mask is used for photolithography to form the corresponding mask pattern on the wafer.

[0048] Specifically, optical proximity correction processing of the design pattern 110 in two adjacent sub-regions 210 includes: referencing Figure 8 Step S21: In two adjacent sub-regions 210, one sub-region 210 is designated as the first region 211 and the other sub-region 210 is designated as the second region 212. A buffer zone 220 is formed at the junction of the first region 211 and the second region 212 in the second region 212. The remaining region in the second region 212, excluding the buffer zone 220, is designated as the fixed region 240.

[0049] It should be noted that, for ease of illustration, Figure 8 for Figure 7 A magnified view of the two adjacent sub-regions 210 where the design graphic 110 is located within the dashed box.

[0050] Buffer 220 is the area where the results need to be adjusted and corrected later. The target corrected graphic of the design graphic 110 located in buffer 220 is obtained by combining the corresponding correction results in the two adjacent sub-regions 210. This is conducive to obtaining a more accurate target corrected graphic in buffer 220. Moreover, buffer 220 is located at the boundary of the two adjacent sub-regions 210, which is conducive to a smoother transition of the final target corrected graphic at the boundary of the two adjacent sub-regions 210.

[0051] The design pattern 110 in the remaining area of ​​the second region 212, excluding the buffer 220, is far from the boundary between the first region 211 and the second region 212 and is less affected by the first region 211. Therefore, the remaining area of ​​the second region 212, excluding the buffer 220, is designated as the fixed region 240, and the subsequent correction results in the fixed region 240 are not adjusted.

[0052] In this embodiment, the width L2 of the buffer zone 220 along the boundary perpendicular to the first region 211 and the second region 212 should not be too large or too small. If the width L2 of the buffer zone 220 along the boundary perpendicular to the first region 211 and the second region 212 is too large, the range of subsequent correction results that need to be adjusted will be too large, which will easily increase the computational load of the correction process and thus easily cause unnecessary cost waste. If the width L2 of the buffer zone 220 along the boundary perpendicular to the first region 211 and the second region 212 is too small, the range of correction results to be adjusted at the boundary of the first region 211 and the second region 212 will be too small, resulting in poor accuracy of the target correction pattern in the fixed area 240, which may easily lead to poor optical proximity correction results in the second region 212. Therefore, in this embodiment, the width L2 of the buffer zone 220 along the boundary perpendicular to the first region 211 and the second region 212 is 50nm to 2000nm.

[0053] It should be noted that in the actual optical proximity correction process, while ensuring the accuracy of the target image after correction, we try not to increase the amount of computation in the correction process. The width L2 of the buffer 220 along the intersection of the first region 211 and the second region 212 is set to 100nm to 1000nm.

[0054] In this embodiment, the step of forming the buffer zone 220 includes: shifting each boundary line of the first region 211 outward to form a closed first expansion region 250, and the region surrounding and adjacent to the first region 211 in the first expansion region 250 serves as the buffer zone 220.

[0055] By shifting the boundary lines of the first region 211 outward to form a closed first expansion region 250, optical proximity correction processing is performed on the first expansion region 250 to obtain the target correction image of the first region 211. This is beneficial to taking into account the correction influence of the surrounding areas of the first region 211 on the first region 211, thereby facilitating the obtaining of a more accurate target correction image in the first region 211. Furthermore, the areas surrounding and adjacent to the first region 211 in the first expansion region 250 are all used as buffer zones 220. The buffer zones 220 include the boundaries between the first region 211 and the four adjacent sub-regions 210, thus preparing for subsequent adjustment of the boundary correction results between the first region 211 and each adjacent sub-region 210, which helps to improve the efficiency of adjusting the correction results.

[0056] Specifically, in this embodiment, in the step of forming a closed first expansion region 250, each boundary line of the first region 211 is translated equidistantly to the outside of the first region 211.

[0057] By translating each boundary line of the first region 211 equidistantly outward from the first region 211, the resulting buffer zone 220 can be evenly distributed around the first region 211, which is beneficial for the subsequent adjustment of the correction results around each first region 211 to be more uniform.

[0058] In this embodiment, among two adjacent sub-regions 210, the sub-region 210 with higher correction priority is designated as the first region 211.

[0059] In the two adjacent sub-regions 210, the sub-region 210 with higher correction priority is processed according to the order of correction priority during the actual optical proximity correction process. In order to avoid confusion in the correction process, the target correction pattern in the sub-region 210 that has been corrected will not be modified again. Therefore, in this embodiment, the sub-region 210 with higher correction priority is used as the first region 211, and the buffer 220 is located in the second region 212, which facilitates the subsequent adjustment of the correction results located in the buffer 220.

[0060] Continue to refer to Figure 8 The step of performing optical proximity correction processing on the design pattern 110 in each sub-region 210 further includes: before forming the buffer 220, shifting the boundary line of the sub-region 210 outward to form a closed second expansion region 230; in the step of forming the buffer 220 located in the second region 212 at the junction of the first region 211 and the second region 212, the second expansion region 230 covers the buffer 220.

[0061] Subsequently, by performing optical proximity correction processing on the second extended region 230, the correction results of the first region 211 and the buffer 220 are obtained. This is beneficial to taking into account the correction effects of the regions surrounding the first region 211 and the buffer 220 on the first region 211 and the buffer 220, thereby facilitating the obtaining of more accurate correction results in the first region 211 and the buffer 220, and further facilitating the obtaining of more accurate target-corrected graphics in the first region 211 and the buffer 220.

[0062] In this embodiment, the distance L3 by which the boundary line of sub-region 210 is shifted outward from sub-region 210 is greater than the width L2 of buffer zone 220 along the intersection of the first region 211 and the second region 212, so that the second expansion region 230 can cover buffer zone 220.

[0063] refer to Figure 9 Step S22 is executed to perform optical proximity correction processing on the design pattern 110 in the first region 211 and the buffer 220 to obtain the first correction result.

[0064] In this embodiment, a target corrected graphic 120 located in the first region 211 is formed based on the first correction result.

[0065] It should be noted that, Figure 9 The outline 310 in the second region 212, which is obtained based on the first correction result, is represented by a dashed line.

[0066] It should also be noted that, for the sake of clarity of the illustration, Figure 9 for Figure 8 A magnified view of the design graphic 110 within the dashed circle.

[0067] Based on the first correction result, a target corrected graphic 120 is formed in the first region 211. This can take into account the correction effect of the region surrounding the first region 211 on the first region 211, which is conducive to obtaining a more accurate correction result in the first region 211. This is conducive to obtaining a more accurate target corrected graphic 120 in the first region 211. Moreover, the correction result of the buffer 220 is obtained by combining the first correction result.

[0068] In this embodiment, the design pattern 110 in the second expansion region 230 is subjected to optical proximity correction processing, and the correction results located in the first region 211 and the buffer 220 are retained as the first correction result.

[0069] By performing optical proximity correction processing on the second extended region 230, the correction results of the first region 211 and the buffer 220 are obtained. This is beneficial to taking into account the correction effects of the regions surrounding the first region 211 and the buffer 220 on the first region 211 and the buffer 220. This is beneficial to obtaining a more accurate first correction result in the first region 211 and the buffer 220, and further beneficial to obtaining a more accurate target correction image in the first region 211 and the buffer 220.

[0070] In this embodiment, the first correction result 310 includes a first translation amount c1 of each line segment along the vertical direction, where the vertical direction is perpendicular to the extension direction of the line segment.

[0071] In this embodiment, the outline of the design graphic 110 is divided into multiple line segments connected end to end. By adjusting the position of the line segments (e.g., translating the line segments) to reduce edge placement error, optical proximity correction processing is performed on the first region 211 and the buffer zone 220, which is to translate the line segments along the vertical direction. Therefore, the first correction result includes the first translation amount c1 of each line segment along the vertical direction.

[0072] refer to Figure 10 Step S23: Perform optical proximity correction processing on the design graphic 110 in the second region 212 to obtain the second correction result.

[0073] In this embodiment, a first corrected graphic located in a fixed region 240 is formed based on the second correction result.

[0074] It should be noted that, Figure 10 In the second region 212, the outline 320 is obtained based on the second correction result, using dashed lines.

[0075] It should also be noted that, for clarity, the first corrected figure located in fixed area 240 is not shown.

[0076] The design graphic 110 in the fixed region 240 is far from the boundary line between the first region 211 and the second region 212, and is less affected by the first region 211. Therefore, the first corrected graphic located in the fixed region 240 can be directly formed based on the second correction result.

[0077] In this embodiment, the design pattern 110 in the second expansion region 230 is subjected to optical proximity correction processing, and the correction result located in the second region 212 is retained as the second correction result.

[0078] To ensure that each sub-region 210 obtains a more accurate correction result, in the step of performing optical proximity correction processing on each sub-region 210, each sub-region 210 forms a corresponding second expansion region 230. In this embodiment, for clarity of illustration, Figure 7 The image only shows the case where the second expansion region 230 is formed corresponding to the first region 211, and does not show the second expansion region 230 corresponding to the second region 212.

[0079] By performing optical proximity correction processing on the second extended region 230, the correction result in the second region 212 is obtained. This is beneficial to taking into account the correction influence of the region surrounding the second region 212 on the second region 212, thereby facilitating the obtaining of a more accurate second correction result in the second region 212, and further facilitating the obtaining of a more accurate first correction image in the second region 212.

[0080] In this embodiment, the second correction result includes the second translation amount c2 of each line segment along the vertical direction.

[0081] In this embodiment, the outline of the design graphic 110 is divided into multiple line segments connected end to end. By adjusting the position of the line segments (e.g., translating the line segments) to reduce edge placement error, the second region 212 is subjected to optical proximity correction processing, which is to translate the line segments along the vertical direction. Therefore, the second correction result includes the second translation amount c2 of each line segment along the vertical direction.

[0082] In this embodiment, the first translation amount c1 and the second translation amount c2 are both used as reference amounts for obtaining the third correction result of the buffer 220.

[0083] Reference Figure 10 and Figure 11 Step S24: Combine the first correction result and the second correction result to obtain the third correction result corresponding to buffer 220.

[0084] In this embodiment, a second corrected graphic 130 is formed in buffer 220 based on the third correction result. The second corrected graphic 130 and the first corrected graphic in the second region 212 constitute the target corrected graphic of the second region 212.

[0085] It should be noted that in this embodiment, in two adjacent sub-regions 210, the third correction result located in the buffer 220 is obtained by combining the first correction result and the second correction result. The two adjacent sub-regions 210 also include two adjacent sub-regions 210 along the diagonal direction with the same vertex. The optical proximity correction processing of the two adjacent sub-regions 210 along the diagonal direction will also affect each other. In the two adjacent sub-regions 210 along the diagonal direction, the third correction result in the buffer 220 should also be obtained by combining the first correction result and the second correction result in the two adjacent sub-regions 210 along the diagonal direction. However, in the actual optical proximity correction process, since the two adjacent sub-regions 210 along the diagonal direction only overlap in vertex, the mutual influence between the correction results of the two adjacent sub-regions 210 along the diagonal direction is small. Therefore, in this embodiment, the example of adjacent sub-regions 210 with overlapping edges that are horizontally or vertically adjacent is used for explanation.

[0086] It should also be noted that, in this embodiment, in the step of performing optical proximity correction processing on the design graphic in the second region, optical proximity correction processing is performed on the design graphic 110 in the second region 212 until the edge placement error of the obtained second correction result converges. Then, the first correction result and the second correction result are combined to obtain the third correction result corresponding to the buffer 220. In other embodiments, after performing optical proximity correction processing on the design graphic in the second region, the first correction result and the second correction result are combined to obtain the third correction result corresponding to the buffer. Then, the optical proximity correction processing on the design graphic in the second region is performed again, thereby iteratively processing the first correction result and the second correction result to obtain the third correction result corresponding to the buffer. After iterative processing, the edge placement error of the obtained second correction result converges.

[0087] In this embodiment, a buffer zone 220 is formed at the boundary between the first region 211 and the second region 212. The second corrected graphic 130 formed in the buffer zone 220 comprehensively considers both the first and second correction results. Compared to the scheme where the first corrected graphic formed based on the second correction result is directly used as the target corrected graphic in the buffer zone, this scheme comprehensively considers both the first and second correction results, resulting in a transitional second correction between the target corrected graphic of the first region 211 and the target corrected graphic of the fixed region 240 in the second region 212 at the boundary between the first region 211 and the second region 212. The final graphic 130 is designed to minimize the difference in correction results at the junction of the first region 211 and the second region 212 due to differences in the correction environment caused by the separate optical proximity correction processing of the first region 211 and the second region 212. This ensures that after the various sub-regions 210 are stitched together, the edge placement error of the target corrected graphic at the junction of the first region 211 and the second region 212 is minimized due to the large difference in correction results at the junction of the first region 211 and the second region 212. This, in turn, helps to make the optical proximity correction processing of the design graphic 110 more accurate.

[0088] In this embodiment, the step of obtaining the third correction result corresponding to the buffer 220 by combining the first correction result and the second correction result includes: weighting the first correction result and the second correction result in the buffer 220 to obtain the third correction result.

[0089] This embodiment performs weighted processing on the first and second correction results to obtain the third correction result. This is beneficial because it comprehensively considers the first and second correction results to obtain the third correction result. Furthermore, it assigns weights to the first and second correction results based on their different impacts on the third correction result, and then performs weighted processing. This is beneficial because it helps to obtain a more accurate third correction result after weighing the first and second correction results.

[0090] In this embodiment, the step of weighting the first correction result and the second correction result includes: weighting the first translation amount c1 and the second translation amount c2 of each line segment to obtain the third translation amount c0 of the corresponding line segment in the buffer 220 along the vertical direction.

[0091] Specifically, using the expression ΔC i =W i ×ΔC high,i +(1-W i )×ΔC low,i The third translation c0 is obtained, where ΔC i The third translation amount c0, ΔC of the i-th line segmenthigh,i Let c1 be the first translation of the i-th line segment, and ΔC be the first translation amount. low,i Let c2 be the second translation amount of the i-th line segment, and W be the second translation amount of the i-th line segment. i Let c1 be the weight of the first translation amount of the i-th line segment.

[0092] In this embodiment, the outline of the design graphic 110 is divided into multiple line segments connected end to end. By adjusting the position of the line segments (e.g., translating the line segments), the edge placement error is reduced. The third correction result is the third translation amount c0 of each line segment along the vertical direction. At the same time, the first correction result includes the first translation amount c1 of each line segment along the vertical direction, and the second correction result includes the second translation amount c2 of each line segment along the vertical direction. Therefore, in this embodiment, by weighting the first translation amount c1 and the second translation amount c2 of each line segment, the third translation amount c0 of the corresponding line segment along the vertical direction in the buffer 220 is obtained.

[0093] Accordingly, in this embodiment, the line segments in the third correction result obtained based on the third translation amount c0 are connected end to end, which is the second corrected graphic 130 located in the buffer zone 220.

[0094] In this embodiment, the step of weighting the first translation amount c1 and the second translation amount c2 of each line segment includes: setting a reference point 30 at the same distance from any endpoint on the same side on each line segment; and obtaining the weights corresponding to the first translation amount c1 and the second translation amount c2 of each line segment based on the edge placement errors corresponding to the first correction result and the second correction result, and the vertical distance L1 between the reference point 30 and the boundary between the first region 211 and the second region 212.

[0095] In this embodiment, reference point 30 is used as a reference benchmark to measure the vertical distance L1 between each line segment and the boundary of the first region 211 and the second region 212. In order to make the reference benchmark of each line segment the same, the reference point 30 on each line segment is equidistant from the endpoint on the same side. As an example, this embodiment uses the midpoint of each line segment as reference point 30. In other embodiments, the endpoint on the same side of each line segment can also be used as reference point.

[0096] During the correction process, an optical model and a photoresist photochemical reaction model are used to calculate the simulated image of the design pattern 110 after exposure. Model-based optical proximity correction identifies the edges corresponding to the contour of the design pattern 110. The simulated image after exposure is compared with the identified contour of the target pattern 110; the difference between them is called edge placement error (EPE). Edge placement error is an indicator used to measure the quality of correction; the smaller the edge placement error, the closer the exposed image is to the design pattern 110.

[0097] Accordingly, in this embodiment, the first correction result corresponds to the first simulated graphic, the second correction result corresponds to the second simulated graphic, and the edge placement error of the first simulated graphic and the second simulated graphic is the edge placement error corresponding to the first correction result and the second correction result.

[0098] In this embodiment, the difference in the vertical distance L1 between the line segment and the boundary of the first region 211 and the second region 212, as well as the difference in the corresponding edge placement error, in the first correction result and the second correction result, all have different effects on the third correction result. Therefore, in this embodiment, based on the edge placement error corresponding to the first correction result and the second correction result, and the vertical distance L1 between the reference point 30 and the boundary of the first region 211 and the second region 212, the weights corresponding to the first translation c1 and the second translation c2 of each line segment are obtained.

[0099] In this embodiment, the steps of obtaining the weights corresponding to the first translation amount c1 and the second translation amount c2 for each line segment include: constructing a first function with the edge placement error as the variable; constructing a second function with the vertical distance L1 between the reference point 30 and the boundary of the first region 211 and the second region 212 as the variable; and performing weighted processing on the first function and the second function to obtain the weights corresponding to each first translation amount c1 and the second translation amount c2.

[0100] By constructing a first function and a second function, the influence of edge placement error and the vertical distance L1 at the intersection of reference point 30 and the first region 211 and the second region 212 is represented by a function. By quantifying the influencing factors of the first correction result and the second correction result, it is beneficial to accurately obtain the degree of influence of the first correction result and the second correction result on obtaining the third correction result. Then, the first function and the second function are weighted to obtain the weights corresponding to each first translation amount c1 and the second translation amount c2. This is beneficial to accurately obtain the weights corresponding to the first translation amount c1 and the second translation amount c2. Moreover, using a function makes it easy to obtain the weights corresponding to the first translation amount c1 and the second translation amount c2, and it has wide applicability.

[0101] Specifically, in this embodiment, the first function is Among them, S high，i S represents the edge placement error of the i-th line segment based on the first correction result. low，i The edge placement error of the i-th line segment based on the second correction result.

[0102] In this embodiment, when the first correction result is better, the edge placement error of the first correction result is smaller, while the edge placement error of the second correction result is larger. Therefore, in the step of weighting the first correction result and the second correction result, the weight of the first correction result should be larger, while the weight of the second correction result should be smaller, so that the third correction result is closer to the first correction result.

[0103] Similarly, for the first and second correction results, when the second correction result is better, the weight of the first correction result should be smaller and the weight of the second correction result should be larger, so that the third correction result is closer to the second correction result.

[0104] Accordingly, in the first function f(s) of this embodiment, when the first correction result is good, S high,i The value of S is small. low,i The value of f(s) is relatively large, which means that the value of the first function f(s) is relatively large. The weight c1 of the first translation obtained by adding weight to the first function f(s) is relatively large, and the weight c2 of the second translation is relatively small, which satisfies the requirement that the third correction result is closer to the first correction result.

[0105] Similarly, when the second correction result is better, the first function f(s) also satisfies the requirement that the third correction result is closer to the second correction result.

[0106] In this embodiment, the second function is Where L1 is the vertical distance between the reference point 30 and the boundary between the first region 211 and the second region 212, and L2 is the width of the buffer zone 220.

[0107] In this embodiment, for the first correction result and the second correction result, the smaller the vertical distance L1 between the reference point 30 and the boundary between the first region 211 and the second region 212, the larger the weight of the first correction result and the second correction result should be in the step of weighting the first correction result and the second correction result, so that the third correction result is closer to the first correction result. Conversely, the larger the vertical distance L1 between the reference point 30 and the boundary between the first region 211 and the second region 212, the smaller the weight of the first correction result should be and the larger the weight of the second correction result, so that the third correction result is closer to the second correction result.

[0108] Accordingly, in the second function f(L1) of this embodiment, the smaller the vertical distance L1 between the reference point 30 and the boundary between the first region 211 and the second region 212, the larger the value of f(L1). Subsequently, the weight c1 of the first translation amount obtained by adding weight to the second function f(L1) is larger, and the weight c2 of the second translation amount is smaller, which satisfies the requirement that the third correction result is closer to the first correction result.

[0109] Similarly, the greater the vertical distance L1 between the reference point 30 and the boundary between the first region 211 and the second region 212, the smaller the value of f(L1), and the second function f(L1) also satisfies the requirement that the third correction result is closer to the second correction result.

[0110] In this embodiment, the expression W is used. i =α×f(s)+(1-α)×f(L1), weighting the first and second functions, where W i Let c1 be the weight of the first translation of the i-th line segment, α be the weight of the first function, and 1-α be the weight of the second function.

[0111] Correspondingly, 1-W i Let c2 be the weight of the second translation amount of the i-th line segment.

[0112] In this embodiment, the weight W of the first translation amount c1 i The weight W of the first translation amount c1 is directly proportional to the value of the first function f(s). i The value of the second function f(L1) is also directly proportional to the value of the first correction result. This satisfies the aforementioned adjustment method for obtaining the third correction result, and correspondingly, the weight of the second translation c2 is 1-W. i This also satisfies the aforementioned adjustment method for the second correction result in order to obtain the third correction result.

[0113] It should be noted that in this embodiment, the weight α of the first function is set according to the actual influence of the first function and the second function during the optical proximity correction process. The weight α of the first function should not be too large or too small. If the weight α of the first function is too large, then the weight W of the first translation amount c1 is calculated. i At that time, if the influence of the first function is too large and the influence of the second function is too small, it can easily lead to an imbalance in the weight W of the first translation amount c1. i The excessive bias towards the value of the first function leads to an imbalance in the weight W of the first translation c1. iOveremphasizing the impact of edge placement errors while neglecting the influence of the vertical distance L1 at the intersection of reference point 30 and the first region 211 and the second region 212 can easily lead to inaccurate calculation of the weights of both the first translation amount c1 and the second translation amount c2, thus affecting the results of optical proximity correction processing. If the weight α of the first function is too small, the weight W of the first translation amount c1 will be calculated. i At that time, if the influence of the first function is too small and the influence of the second function is too large, it can easily lead to an imbalance in the weight W of the first translation amount c1. i The excessive bias towards the value of the second function leads to an imbalance in the weight W of the first translation, c1. i The influence of edge placement error is overly ignored, while the influence of the vertical distance L1 at the intersection of reference point 30 and the first region 211 and the second region 212 is overemphasized. This can easily lead to inaccurate calculation of the weights of the first translation amount c1 and the second translation amount c2, thus affecting the result of the optical proximity correction processing. Therefore, in this embodiment, the weight α of the first function is between 0.3 and 0.8. For example, the weight α of the first function is 0.4, 0.5, or 0.7.

[0114] In this embodiment, after optical proximity correction processing is performed on the design graphics 110 in each sub-region 210, the optical proximity correction method further includes: splicing the sub-regions 210 together.

[0115] In this embodiment, the difference in correction results at the junction of the first region 211 and the second region 212 due to differences in the correction environment caused by the optical proximity correction processing of the first region 211 and the second region 212 is avoided as much as possible. This facilitates more accurate splicing of the sub-regions 210. Furthermore, after splicing the sub-regions 210, the difference in correction results at the junction of the first region 211 and the second region 212 is avoided as much as possible. This avoids the situation where the edge placement error of the target corrected graphic at the junction of the first region 211 and the second region 212 is too large, which in turn facilitates more accurate optical proximity correction processing of the design graphic 110.

[0116] Accordingly, the present invention also provides an optical proximity correction system. Figure 12 This is a functional block diagram of an embodiment of the optical proximity correction system of the present invention. Figure 13 This is a functional block diagram of the correction module in one embodiment of the optical proximity correction system of the present invention.

[0117] In this embodiment, the optical proximity correction system 50 includes: a layout acquisition module 501, used to acquire a design layout, the design layout including multiple design graphics, the design layout being divided into multiple sub-regions, the multiple sub-regions being distributed in a matrix; and a correction module 502, used to perform optical proximity correction processing on the design graphics in each sub-region to obtain the target corrected graphics located in each sub-region.

[0118] The correction module 502 performs optical proximity correction processing on the design graphics in two adjacent sub-regions, including: a region setting unit 5021, which is used to form a buffer zone in the second region at the boundary between the first and second regions, with one sub-region as the first region and the other sub-region as the second region; and the remaining region in the second region excluding the buffer zone as the fixed region; a first correction unit 5022, which performs optical proximity correction processing on the design graphics in the first region and the buffer zone to obtain a first correction result for the first region and the buffer zone; a second correction unit 5023, which performs optical proximity correction processing on the design graphics in the second region to obtain a second correction result; and a third correction unit 5024, which combines the first correction result and the second correction result to obtain a third correction result corresponding to the buffer zone.

[0119] The graphics providing module 501 is used to obtain the design layout, which includes multiple design graphics. The design layout is divided into multiple sub-regions, which are distributed in a matrix.

[0120] The design pattern is the target pattern transferred onto the wafer. After optical proximity correction is performed on the design pattern, the obtained pattern is used to make a mask, and then the photolithography process is performed on the mask to form the corresponding mask pattern on the wafer.

[0121] Since the area of ​​the design layout is usually large, it is divided into multiple sub-regions. By performing optical proximity correction on each sub-region separately and then stitching the processed sub-regions together, the optical proximity correction of the design layout is achieved. This helps to avoid the time-consuming process of performing optical proximity correction on a large area, thus saving the processing time of the optical proximity correction.

[0122] In this embodiment, a corresponding correction priority is set for each sub-region.

[0123] By setting a corresponding correction priority for each sub-region, each sub-region is corrected sequentially according to its corresponding correction priority in the subsequent steps of optical proximity correction processing of the design graphics in each sub-region. This helps to avoid correction oscillations at the boundaries of adjacent sub-regions due to the combined influence of adjacent sub-regions when all sub-regions are corrected at the same time, thus making it difficult to obtain a definite correction result. This helps to reduce the probability of disordered correction results at the boundaries of adjacent sub-regions, and thus helps to obtain more accurate optical proximity correction results.

[0124] As an example, this embodiment sets the correction priority of the sub-regions to four levels, labeled as 0, 1, 2 and 3 respectively, with the correction priority decreasing from 0 to 3. The correction priorities of the four sub-regions that intersect at the same point are set to 0, 1, 2 and 3 respectively.

[0125] In this embodiment, before performing optical proximity correction processing on the design graphics in each sub-region, the method further includes: dividing the edges of the design graphics in each sub-region and forming multiple line segments connected end to end along the outline of the design graphics.

[0126] In the subsequent optical proximity correction process for the design graphic, to reduce the arbitrariness of edge movement, the position of line segments is adjusted (e.g., line segments are translated) to reduce edge placement errors. In this embodiment, multiple line segments connected end-to-end are formed along the outline of the design graphic, and the position of the line segments is subsequently adjusted for optical proximity correction.

[0127] The correction module 502 is used to perform optical proximity correction processing on the design graphics in each sub-region to obtain the target corrected graphics located in each sub-region.

[0128] After optical proximity correction is performed on the design pattern, the resulting pattern is used to create a photomask, which is then used for photolithography to form the corresponding photomask pattern on the wafer.

[0129] Specifically, in the correction module 502, the optical proximity correction processing of the design graphics in two adjacent sub-regions includes: setting a region unit 5021, which is used to form a buffer zone in the second region at the junction of the first region and the second region, with one sub-region as the first region and the other sub-region as the second region, and the remaining region in the second region other than the buffer zone as the fixed region.

[0130] The buffer is the area where the results need to be adjusted and corrected later. The target corrected graphic of the design graphic located in the buffer is obtained by combining the corresponding correction results of the two adjacent sub-regions. This is conducive to obtaining a more accurate target corrected graphic in the buffer. Moreover, the buffer is located at the boundary of the two adjacent sub-regions, which helps to make the final target corrected graphic transition more smoothly at the boundary of the two adjacent sub-regions.

[0131] The design graphics in the remaining area of ​​the second region, excluding the buffer zone, are far from the boundary between the first and second regions and are less affected by the first region. Therefore, the remaining area of ​​the second region, excluding the buffer zone, is treated as a fixed region, and the correction results in the subsequent fixed region will not be adjusted.

[0132] In this embodiment, the width L2 of the buffer zone perpendicular to the boundary between the first and second regions should not be too large or too small. If the width L2 of the buffer zone perpendicular to the boundary between the first and second regions is too large, the range of subsequent correction results that need to be adjusted will be too large, easily increasing the computational load of the correction process. This could lead to unnecessary cost waste while ensuring the accuracy of the target correction image at the boundary between the first and second regions. If the width L2 of the buffer zone perpendicular to the boundary between the first and second regions is too small, the range of correction results that need to be adjusted at the boundary between the first and second regions will be too small. This could result in poor accuracy of the target correction image in the fixed area, potentially leading to poor optical proximity correction results in the second region. Therefore, in this embodiment, the width L2 of the buffer zone perpendicular to the boundary between the first and second regions is between 50 nm and 2000 nm.

[0133] It should be noted that in the actual optical proximity correction process, while ensuring the accuracy of the target image after correction, we try not to increase the amount of computation in the correction process. The width L2 of the buffer 220 along the boundary between the first region and the second region is set to 100nm to 1000nm.

[0134] In this embodiment, the boundary lines of the first region are shifted outward to form a closed first expansion region, and the region surrounding and adjacent to the first region in the first expansion region serves as a buffer zone.

[0135] By shifting the boundary lines of the first region outward to form a closed first expansion region, optical proximity correction processing is performed on the first expansion region to obtain the target correction image of the first region. This is beneficial because the correction influence of the surrounding areas of the first region on the first region is taken into account, which helps to obtain a more accurate target correction image in the first region. Moreover, the areas surrounding and adjacent to the first region in the first expansion region are all used as buffer zones. The buffer zones include the boundaries between the first region and the four adjacent sub-regions, which can prepare for the subsequent adjustment of the boundary correction results between the first region and each adjacent sub-region, which helps to improve the efficiency of the correction result adjustment.

[0136] Specifically, in this embodiment, in the step of forming a closed first expansion region, the boundary lines of the first region are shifted equidistantly to the outside of the first region.

[0137] By shifting each boundary line of the first region equidistantly to the outside of the first region, the resulting buffer zones can be evenly distributed around the first region, which is beneficial for making the subsequent adjustments to the correction results around each first region more uniform.

[0138] In this embodiment, among two adjacent sub-regions, the sub-region with the higher correction priority is designated as the first region.

[0139] In the actual optical proximity correction process, the sub-region with higher correction priority is corrected according to the order of correction priority. In order to avoid confusion in the correction process, the target correction pattern in the sub-region that has been corrected will not be modified again. Therefore, in this embodiment, the sub-region with higher correction priority is used as the first region, and the buffer is located in the second region to facilitate subsequent adjustment of the correction results located in the buffer.

[0140] In this embodiment, before forming the buffer zone, the boundary line of the sub-region is shifted outward to form a closed second expansion region, which covers the buffer zone.

[0141] Subsequently, by performing optical proximity correction processing on the second expanded region, the correction results of the first region and the buffer are obtained. This is beneficial to taking into account the correction effects of the regions surrounding the first region and the buffer on the first region and the buffer, thereby facilitating the obtaining of more accurate correction results in the first region and the buffer, and consequently, obtaining more accurate target-corrected graphics in the first region and the buffer.

[0142] In this embodiment, the distance L3 by which the boundary line of the sub-region is shifted outward from the sub-region is greater than the width L2 of the buffer zone at the intersection of the first and second regions perpendicular to it, so that the second expansion region can cover the buffer zone.

[0143] The correction module 502 further includes: a first correction unit 5022, used to perform optical proximity correction processing on the design pattern in the first region and the buffer to obtain a first correction result, and form a target corrected pattern located in the first region based on the first correction result.

[0144] The target correction graphic in the first region is formed based on the first correction result, which can take into account the correction effect of the surrounding areas on the first region, thus facilitating the obtaining of a more accurate correction result in the first region, and thus facilitating the obtaining of a more accurate target correction graphic in the first region. Furthermore, the correction result of the buffer zone is obtained by combining the first correction result.

[0145] In this embodiment, the design pattern in the second expansion region is subjected to optical proximity correction processing, and the correction results located in the first region and the buffer are retained as the first correction result.

[0146] By performing optical proximity correction on the second expanded region, the correction results of the first region and the buffer are obtained. This is beneficial to taking into account the correction effects of the regions surrounding the first region and the buffer on the first region and the buffer, thereby facilitating the obtaining of a more accurate first correction result in the first region and the buffer, and further facilitating the obtaining of a more accurate target-corrected image in the first region and the buffer.

[0147] In this embodiment, the first correction result includes a first translation amount c1 of each line segment along the vertical direction, where the vertical direction is perpendicular to the extension direction of the line segment.

[0148] In this embodiment, the outline of the design graphic is divided into multiple line segments connected end to end. By adjusting the position of the line segments (e.g., translating the line segments) to reduce edge placement error, optical proximity correction processing is performed on the first region and the buffer zone, which is to translate the line segments along the vertical direction. Therefore, the first correction result includes the first translation amount c1 of each line segment along the vertical direction.

[0149] The correction module 502 further includes a second correction unit 5023, which performs optical proximity correction processing on the design graphic in the second region to obtain a second correction result, and forms a first corrected graphic located in a fixed region based on the second correction result.

[0150] The design graphic in the fixed region is far from the boundary between the first and second regions and is less affected by the first region. Therefore, the first corrected graphic located in the fixed region can be directly formed based on the second correction result.

[0151] In this embodiment, the design pattern in the second expansion region is subjected to optical proximity correction processing, and the correction result located in the second region is retained as the second correction result.

[0152] In order to obtain a more accurate correction result for each sub-region, in the step of optical proximity correction processing for each sub-region, a corresponding second expansion region is formed for each sub-region.

[0153] By performing optical proximity correction on the second expansion region, the correction result in the second region is obtained. This is beneficial to taking into account the correction influence of the surrounding areas on the second region, which is conducive to obtaining a more accurate second correction result in the second region, and thus to obtaining a more accurate first correction image in the second region.

[0154] In this embodiment, the second correction result includes the second translation amount c2 of each line segment along the vertical direction.

[0155] In this embodiment, the outline of the design graphic is divided into multiple line segments connected end to end. By adjusting the position of the line segments (e.g., translating the line segments) to reduce edge placement error, the second region is subjected to optical proximity correction processing, which is to translate the line segments along the vertical direction. Therefore, the second correction result includes the second translation amount c2 of each line segment along the vertical direction.

[0156] In this embodiment, the first translation amount c1 and the second translation amount c2 are both used as reference amounts for obtaining the third correction result of the buffer in the future.

[0157] The correction module 502 further includes a third correction unit 5024, which combines the first correction result and the second correction result to obtain the third correction result corresponding to the buffer, and forms a second corrected graphic located in the buffer based on the third correction result. The second corrected graphic and the first corrected graphic located in the second region constitute the target corrected graphic of the second region.

[0158] It should be noted that in this embodiment, in two adjacent sub-regions, the first correction result and the second correction result are combined to obtain the third correction result located in the buffer zone. The two adjacent sub-regions also include two adjacent sub-regions along the diagonal direction with the same vertex. The optical proximity correction processing of two adjacent sub-regions along the diagonal direction will also affect each other. In two adjacent sub-regions along the diagonal direction, the third correction result in the buffer zone should also be obtained by combining the first correction result and the second correction result in the two adjacent sub-regions along the diagonal direction. However, in the actual optical proximity correction process, since the two adjacent sub-regions along the diagonal direction only overlap in vertex, the mutual influence between the correction results of the two adjacent sub-regions along the diagonal direction is small. Therefore, in this embodiment, adjacent sub-regions with overlapping edges that are horizontally or vertically adjacent are used as examples for explanation.

[0159] It should also be noted that, in this embodiment, in the step of performing optical proximity correction processing on the design graphic in the second region, the optical proximity correction processing is performed on the design graphic in the second region until the edge placement error of the obtained second correction result converges. Then, the first correction result and the second correction result are combined to obtain the third correction result corresponding to the buffer. In other embodiments, after performing optical proximity correction processing on the design graphic in the second region, the first correction result and the second correction result are combined to obtain the third correction result corresponding to the buffer. Then, the optical proximity correction processing on the design graphic in the second region is performed again, thereby iteratively processing the first correction result and the second correction result to obtain the third correction result corresponding to the buffer. After iterative processing, the edge placement error of the obtained second correction result converges.

[0160] In this embodiment, a buffer zone is formed at the boundary between the first and second regions. The second corrected graphic formed in the buffer zone takes into account both the first and second correction results. Compared to the scheme where the first corrected graphic formed based on the second correction result is directly used as the target corrected graphic in the buffer zone, this scheme takes into account both the first and second correction results. This results in a transitional second corrected graphic between the target corrected graphic of the first region and the target corrected graphic of the fixed region in the second region at the boundary between the first and second regions. This avoids the situation where the correction results at the boundary between the first and second regions differ too much due to differences in the correction environment caused by the optical proximity correction processing performed separately by the first and second regions. As a result, after the various sub-regions are stitched together, the situation where the edge placement error of the target corrected graphic at the boundary between the first and second regions is too large due to the large difference in the correction results at the boundary is avoided as much as possible. This makes the optical proximity correction processing of the design graphic more accurate.

[0161] In this embodiment, the first correction result and the second correction result are weighted in the buffer to obtain the third correction result.

[0162] This embodiment performs weighted processing on the first and second correction results to obtain the third correction result. This is beneficial because it comprehensively considers the first and second correction results to obtain the third correction result. Furthermore, it assigns weights to the first and second correction results based on their different impacts on the third correction result, and then performs weighted processing. This is beneficial because it helps to obtain a more accurate third correction result after weighing the first and second correction results.

[0163] In this embodiment, the first translation amount c1 and the second translation amount c2 of each line segment are weighted to obtain the third translation amount c0 of the corresponding line segment in the buffer along the vertical direction.

[0164] Specifically, using the expression ΔC i =W i ×ΔC high,i +(1-W i )×ΔC low,i The third translation c0 is obtained, where ΔC i The third translation amount c0, ΔC of the i-th line segment high,i Let c1 be the first translation of the i-th line segment, and ΔC be the first translation amount. low,i Let c2 be the second translation amount of the i-th line segment, and W be the second translation amount of the i-th line segment. i Let c1 be the weight of the first translation amount of the i-th line segment.

[0165] In this embodiment, the outline of the design graphic is divided into multiple line segments connected end to end. By adjusting the position of the line segments (e.g., translating the line segments), the edge placement error is reduced. The third correction result is the third translation amount c0 of each line segment along the vertical direction. At the same time, the first correction result includes the first translation amount c1 of each line segment along the vertical direction, and the second correction result includes the second translation amount c2 of each line segment along the vertical direction. Therefore, this embodiment obtains the third translation amount c0 of the corresponding line segment along the vertical direction in the buffer by weighting the first translation amount c1 and the second translation amount c2 of each line segment.

[0166] Accordingly, in this embodiment, the line segments in the third correction result obtained based on the third translation amount c0 are connected end to end, which is the second corrected graphic located in the buffer zone.

[0167] In this embodiment, a reference point is set on each line segment at the same distance from any endpoint on the same side; based on the edge placement error corresponding to the first correction result and the second correction result, and the vertical distance L1 between the reference point and the boundary between the first region and the second region, the weights corresponding to the first translation c1 and the second translation c2 of each line segment are obtained.

[0168] In this embodiment, the reference point is used as a reference benchmark to measure the vertical distance L1 between each line segment and the boundary between the first region and the second region. In order to make the reference benchmark of each line segment the same, the reference point on each line segment is equidistant from the endpoint on the same side. As an example, this embodiment uses the midpoint of each line segment as the reference point. In other embodiments, the endpoint on the same side of each line segment can also be used as the reference point.

[0169] During the correction process, optical models and photoresist photochemical reaction models are used to calculate the simulated image of the design pattern after exposure. Model-based optical proximity correction identifies the edges corresponding to the outline of the design pattern. The simulated image after exposure is compared with the identified target image outline; the difference between the two is called edge placement error. Edge placement error is an indicator used to measure the quality of correction; the smaller the edge placement error, the closer the exposed image is to the design pattern.

[0170] Accordingly, in this embodiment, the first correction result corresponds to the first simulated graphic, the second correction result corresponds to the second simulated graphic, and the edge placement error of the first simulated graphic and the second simulated graphic is the edge placement error corresponding to the first correction result and the second correction result.

[0171] In this embodiment, the difference in the vertical distance L1 between the line segment and the boundary between the first region and the second region, as well as the difference in the corresponding edge placement error, in the first correction result and the second correction result, all have different effects on the third correction result. Therefore, in this embodiment, the weights corresponding to the first translation amount c1 and the second translation amount c2 of each line segment are obtained based on the edge placement error corresponding to the first correction result and the second correction result, as well as the vertical distance L1 between the reference point and the boundary between the first region and the second region.

[0172] In this embodiment, a first function with edge placement error as the variable is constructed; a second function with the vertical distance L1 between the reference point and the boundary between the first region and the second region as the variable is constructed; the first function and the second function are weighted to obtain the weights corresponding to each first translation amount c1 and the second translation amount c2.

[0173] By constructing a first function and a second function, the influence of edge placement error and the vertical distance L1 between the reference point and the boundary between the first and second regions is represented by a function. By quantifying the influencing factors of the first and second correction results, it is beneficial to accurately obtain the degree of influence of the first and second correction results on obtaining the third correction result. Then, the first function and the second function are weighted to obtain the weights corresponding to each first translation amount c1 and second translation amount c2. This is beneficial to accurately obtain the weights corresponding to the first translation amount c1 and second translation amount c2. Furthermore, using a function makes it simple and easy to operate to obtain the weights corresponding to the first translation amount c1 and second translation amount c2, and it has wide applicability.

[0174] Specifically, in this embodiment, the first function is Among them, S high，i S represents the edge placement error of the i-th line segment based on the first correction result. low，i The edge placement error of the i-th line segment based on the second correction result.

[0175] In this embodiment, when the first correction result is better, the edge placement error of the first correction result is smaller, while the edge placement error of the second correction result is larger. Therefore, in the weighted processing of the first correction result and the second correction result, the weight of the first correction result should be larger, while the weight of the second correction result should be smaller, so that the third correction result is closer to the first correction result.

[0176] Similarly, for the first and second correction results, when the second correction result is better, the weight of the first correction result should be smaller and the weight of the second correction result should be larger, so that the third correction result is closer to the second correction result.

[0177] Accordingly, in the first function f(s) of this embodiment, when the first correction result is good, S high,i The value of S is small. low,i The value of f(s) is relatively large, which means that the value of the first function f(s) is relatively large. The weight c1 of the first translation obtained by adding weight to the first function f(s) is relatively large, and the weight c2 of the second translation is relatively small, which satisfies the requirement that the third correction result is closer to the first correction result.

[0178] Similarly, when the second correction result is better, the first function f(s) also satisfies the requirement that the third correction result is closer to the second correction result.

[0179] In this embodiment, the second function is Where L1 is the vertical distance between the reference point and the boundary between the first and second regions, and L2 is the width of the buffer zone.

[0180] In this embodiment, for the first correction result and the second correction result, the smaller the vertical distance L1 between the reference point and the boundary between the first region and the second region, the more weighted the first correction result and the second correction result should be, so that the weight of the first correction result is larger and the weight of the second correction result is smaller, thereby making the third correction result closer to the first correction result. Conversely, the larger the vertical distance L1 between the reference point and the boundary between the first region and the second region, the smaller the weight of the first correction result should be and the larger the weight of the second correction result, thereby making the third correction result closer to the second correction result.

[0181] Accordingly, in the second function f(L1) of this embodiment, the smaller the vertical distance L1 between the reference point and the boundary between the first region and the second region, the larger the value of f(L1). Subsequently, the weight c1 of the first translation obtained by adding weight to the second function f(L1) is larger, and the weight c2 of the second translation is smaller, which satisfies the requirement that the third correction result is closer to the first correction result.

[0182] Similarly, the larger the vertical distance L1 between the reference point and the boundary between the first and second regions, the smaller the value of f(L1), and the second function f(L1) also satisfies the requirement that the third correction result is closer to the second correction result.

[0183] In this embodiment, the expression W is used. i =α×f(s)+(1-α)×f(L1), weighting the first and second functions, where W i Let c1 be the weight of the first translation of the i-th line segment, α be the weight of the first function, and 1-α be the weight of the second function.

[0184] Correspondingly, 1-W i Let c2 be the weight of the second translation amount of the i-th line segment.

[0185] In this embodiment, the weight W of the first translation amount c1 i The weight W of the first translation amount c1 is directly proportional to the value of the first function f(s). i The value of the second function f(L1) is also directly proportional to the value of the first correction result. This satisfies the aforementioned adjustment method for obtaining the third correction result, and correspondingly, the weight of the second translation c2 is 1-W. i This also satisfies the aforementioned adjustment method for the second correction result in order to obtain the third correction result.

[0186] It should be noted that in this embodiment, the weight α of the first function is set according to the actual influence of the first function and the second function during the optical proximity correction process. The weight α of the first function should not be too large or too small. If the weight α of the first function is too large, then the weight W of the first translation amount c1 is calculated. i At that time, if the influence of the first function is too large and the influence of the second function is too small, it can easily lead to an imbalance in the weight W of the first translation amount c1. i The excessive bias towards the value of the first function leads to an imbalance in the weight W of the first translation c1. i Overemphasizing the impact of edge placement errors while neglecting the influence of the vertical distance L1 between the reference point and the boundary between the first and second regions can easily lead to inaccurate calculation of the weights of both the first and second translation amounts c1 and c2, thus affecting the results of optical proximity correction processing. If the weight α of the first function is too small, the weight W of the first translation amount c1 will be calculated. i At that time, if the influence of the first function is too small and the influence of the second function is too large, it can easily lead to an imbalance in the weight W of the first translation amount c1. i The excessive bias towards the value of the second function leads to an imbalance in the weight W of the first translation, c1. iBy excessively ignoring the impact of edge placement errors and overestimating the influence of the vertical distance L1 between the reference point and the boundary between the first and second regions, the weights of both the first and second translation amounts c1 and c2 can be calculated inaccurately, thus affecting the results of the optical proximity correction processing. Therefore, in this embodiment, the weight α of the first function is set to 0.3 to 0.8. For example, the weight α of the first function can be 0.4, 0.5, or 0.7.

[0187] In this embodiment, after optical proximity correction processing is performed on the design graphics in each sub-region, the optical proximity correction method further includes: stitching the sub-regions together.

[0188] In this embodiment, the difference in correction results at the junction of the first and second regions due to differences in the correction environment caused by the separate optical proximity correction processing of the first and second regions is avoided as much as possible. This facilitates more accurate stitching of sub-regions. Furthermore, after stitching the sub-regions, the difference in correction results at the junction of the first and second regions is avoided as much as possible, which could lead to excessive edge placement error of the target corrected graphic at the junction of the first and second regions. This makes the optical proximity correction processing of the design graphic more accurate.

[0189] Accordingly, the present invention also provides a photomask, comprising: a pattern obtained using the optical proximity correction method provided in the embodiments of the present invention.

[0190] As can be seen from the foregoing embodiments, in this embodiment of the invention, a buffer zone is formed at the junction of the first region and the second region, and the second corrected graphic formed in the buffer zone takes into account both the first and second correction results. Compared with the scheme of directly using the first corrected graphic formed based on the second correction result as the target corrected graphic in the buffer zone, this scheme takes into account both the first and second correction results, so that at the junction of the first region and the second region, there is a transitional second corrected graphic between the target corrected graphic of the first region and the target corrected graphic of the fixed region in the second region. This avoids the situation where the correction results at the junction of the first region and the second region are too different due to the difference in the correction environment caused by the optical proximity correction processing of the first region and the second region, so that after the various sub-regions are stitched together, the situation where the edge placement error of the target corrected graphic at the junction of the first region and the second region is too large due to the large difference in the correction results at the junction of the first region and the second region is avoided as much as possible. This makes the optical proximity correction processing of the design graphic more accurate.

[0191] This invention also provides a device that can implement the optical proximity correction method provided in this invention by loading a program, as described above. An optional hardware structure of the terminal device provided in this invention can be as follows: Figure 14 As shown, it includes: at least one processor 01, at least one communication interface 02, at least one memory 03, and at least one communication bus 04.

[0192] In this embodiment, the number of processor 01, communication interface 02, memory 03, and communication bus 04 is at least one, and the processor 01, communication interface 02, and memory 03 communicate with each other through communication bus 04. Communication interface 02 can be an interface of a communication module for network communication, such as the interface of a GSM module. Processor 01 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. Memory 03 may include high-speed RAM and may also include non-volatile memory (NVM), such as at least one disk storage device. Memory 03 stores one or more computer instructions, which are executed by processor 01 to implement the optical proximity correction method provided in this embodiment of the present invention.

[0193] It should be noted that the aforementioned terminal device may also include other devices (not shown) that may not be essential to understanding the content disclosed in the embodiments of the present invention; given that these other devices may not be essential for understanding the content disclosed in the embodiments of the present invention, the embodiments of the present invention will not describe them one by one.

[0194] This invention also provides a storage medium storing one or more computer instructions for implementing the optical proximity correction method provided in this invention.

[0195] In this embodiment of the invention, a buffer zone is formed at the boundary between the first region and the second region. The second corrected graphic formed in the buffer zone takes into account both the first and second correction results. Compared to the scheme where the first corrected graphic formed based on the second correction result is directly used as the target corrected graphic in the buffer zone, this scheme takes into account both the first and second correction results. This results in a transitional second corrected graphic between the target corrected graphic of the first region and the target corrected graphic of the fixed region in the second region at the boundary between the first and second regions. This avoids the situation where the correction results at the boundary between the first and second regions differ too much due to differences in the correction environment caused by the optical proximity correction processing performed separately by the first and second regions. As a result, after the various sub-regions are stitched together, the situation where the edge placement error of the target corrected graphic at the boundary between the first and second regions is too large due to the large difference in the correction results at the boundary is avoided as much as possible. This makes the optical proximity correction processing of the design graphic more accurate.

[0196] The embodiments of the present invention described above are combinations of elements and features of the present invention. Unless otherwise stated, the elements or features described are optional. Individual elements or features may be practiced without combination with other elements or features. Furthermore, embodiments of the present invention may be constructed by combining some elements and / or features. The order of operations described in the embodiments of the present invention may be rearranged. Some constructions of any embodiment may be included in another embodiment and may be replaced by corresponding constructions of another embodiment. It will be apparent to those skilled in the art that claims in the appended claims that are not expressly referenced to each other may be combined to form embodiments of the present invention, or may be included as new claims in amendments made after the filing of this application.

[0197] Embodiments of the present invention can be implemented by various means, such as hardware, firmware, software, or combinations thereof. In a hardware configuration, the method according to an exemplary embodiment of the present invention can be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc. In a firmware or software configuration, embodiments of the present invention can be implemented in the form of modules, processes, functions, etc. Software code can be stored in memory units and executed by a processor. The memory units are located inside or outside the processor and can send data to and receive data from the processor via various known means.

[0198] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is accorded the widest scope consistent with the principles and novel features disclosed herein.

[0199] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An optical proximity correction method, characterized in that, include: Obtain a design layout, which includes multiple design graphics and is divided into multiple sub-regions, which are distributed in a matrix. Each sub-region is assigned a corresponding correction priority, which is set to four levels, labeled 0, 1, 2 and 3 respectively, with the correction priority decreasing from 0 to 3. The correction priorities of the four sub-regions that intersect at the same point are set to 0, 1, 2 and 3 respectively. The edges of the design graphics in each of the sub-regions are divided, and multiple line segments connected end to end are formed along the outline of the design graphics; Optical proximity correction processing is performed on the design graphics in each of the sub-regions to obtain the target corrected graphics located in each of the sub-regions. Specifically, optical proximity correction processing is performed on the design graphics in two adjacent sub-regions, including: In two adjacent sub-regions, the sub-region with higher correction priority is designated as the first region, and the other sub-region is designated as the second region. A buffer zone is formed at the boundary between the first region and the second region, located in the second region. The remaining region in the second region excluding the buffer zone is designated as a fixed region. Optical proximity correction processing is performed on the design graphics in the first region and buffer to obtain a first correction result for the first region and buffer. The first correction result includes a first translation amount of each line segment along the vertical direction, wherein the vertical direction is perpendicular to the extension direction of the line segment. The design graphic in the second region is subjected to optical proximity correction processing to obtain a second correction result, which includes a second translation amount of each line segment along the vertical direction. The step of obtaining the third correction result corresponding to the buffer by combining the first correction result and the second correction result includes: weighting the first translation amount and the second translation amount of each line segment in the buffer to obtain the third translation amount of the corresponding line segment in the buffer along the vertical direction; wherein, the step of weighting the first translation amount and the second translation amount of each line segment includes: setting a reference point at the same distance from any endpoint on the same side on each line segment; obtaining the weights corresponding to the first translation amount and the second translation amount of each line segment based on the edge placement error corresponding to the first correction result and the second correction result respectively, and the vertical distance between the reference point and the boundary of the first region and the second region; the step of obtaining the weights corresponding to the first translation amount and the second translation amount of each line segment includes: constructing a first function with the edge placement error as a variable; constructing a second function with the vertical distance between the reference point and the boundary of the first region and the second region as a variable; weighting the first function and the second function to obtain the weights corresponding to each first translation amount and the second translation amount.

2. The optical proximity correction method as described in claim 1, characterized in that, In the step of performing optical proximity correction processing on the design graphics in the first region and the buffer, a target corrected graphic located in the first region is formed based on the first correction result. In the step of performing optical proximity correction processing on the design pattern in the second region, a first corrected pattern located in the fixed region is formed based on the second correction result; In the step of obtaining the third correction result corresponding to the buffer by combining the first correction result and the second correction result, a second corrected graphic located in the buffer is formed based on the third correction result. The second corrected graphic and the first corrected graphic located in the second region constitute the target corrected graphic located in the second region.

3. The optical proximity correction method as described in claim 1, characterized in that, In the step of obtaining the third correction result corresponding to the buffer by combining the first correction result and the second correction result, the first correction result and the second correction result are iteratively processed to obtain the third correction result corresponding to the buffer.

4. The optical proximity correction method as described in claim 1, characterized in that, The buffer zone has a width of 50 nm to 2000 nm along the boundary perpendicular to the first region and the second region.

5. The optical proximity correction method as described in claim 1, characterized in that, The steps of forming the buffer zone include: shifting each boundary line of the first region outward to form a closed first expansion region, wherein the region surrounding and adjacent to the first region in the first expansion region serves as the buffer zone.

6. The optical proximity correction method as described in claim 5, characterized in that, In the step of forming a closed first expansion region, the boundary lines of the first region are translated equidistantly outward from the first region.

7. The optical proximity correction method as described in claim 1, characterized in that, In the step of constructing the first function with edge placement error as the variable, the first function is: ,in, The edge placement error of the i-th line segment based on the first correction result. The edge placement error of the i-th line segment based on the second correction result; In the step of constructing a second function with the distance between the reference point and the boundary between the first region and the second region as the variable, the second function is: Where L1 is the vertical distance between the reference point and the boundary between the first region and the second region, and L2 is the width of the buffer zone; Using expressions The first function and the second function are weighted, where, The weight of the first translation of the i-th line segment. The weights of the first function, The weights of the second function.

8. The optical proximity correction method as described in claim 7, characterized in that, The value ranges from 0.3 to 0.

8.

9. The optical proximity correction method as described in claim 1, characterized in that, The step of performing optical proximity correction processing on the design graphics in each of the sub-regions further includes: before forming the buffer zone, shifting the boundary line of the sub-region to the outside of the sub-region to form a closed second expansion region; In the step of forming a buffer zone located in the second region at the boundary between the first region and the second region, the second expanded region covers the buffer zone; Optical proximity correction is performed on the design pattern in the second expansion region, and the correction results located in the first region and the buffer are retained as the first correction result, while the correction results located in the second region are retained as the second correction result.

10. The optical proximity correction method as described in claim 1, characterized in that, After performing optical proximity correction processing on the design graphics in each of the sub-regions, the optical proximity correction method further includes: stitching together the sub-regions.

11. An optical proximity correction system, characterized in that, include: The layout acquisition module is used to acquire a design layout, which includes multiple design graphics and is divided into multiple sub-regions, which are distributed in a matrix. The setting module is used to set a corresponding correction priority for each of the sub-regions. The correction priority is set to four levels, which are identified as 0, 1, 2 and 3 respectively. The correction priority decreases from 0 to 3. The correction priorities of the four sub-regions that intersect at the same point are set to 0, 1, 2 and 3 respectively. The segmentation module is used to segment the edges of the design graphics in each of the sub-regions and form multiple line segments connected end to end along the outline of the design graphics. The correction module is used to perform optical proximity correction processing on the design graphics in each of the sub-regions to obtain the target corrected graphics located in each of the sub-regions. The optical proximity correction processing on the design graphics in two adjacent sub-regions includes: A region unit is defined to select the sub-region with the highest correction priority as the first region and the other sub-region as the second region in two adjacent sub-regions. A buffer zone is formed at the boundary between the first region and the second region in the second region. The remaining region in the second region excluding the buffer zone is defined as a fixed region. The first correction unit is used to perform optical proximity correction processing on the design pattern in the first region and the buffer to obtain a first correction result for the first region and the buffer. The first correction result includes a first translation amount of each line segment along the vertical direction, wherein the vertical direction is perpendicular to the extension direction of the line segment. The second correction unit is used to perform optical proximity correction processing on the design pattern in the second region to obtain a second correction result, the second correction result including a second translation amount of each line segment along the vertical direction; The third correction unit is used to combine the first correction result and the second correction result to obtain the third correction result corresponding to the buffer. The step of obtaining the third correction result corresponding to the buffer includes: weighting the first translation amount and the second translation amount of each line segment in the buffer to obtain the third translation amount of the corresponding line segment along the vertical direction; wherein the step of weighting the first translation amount and the second translation amount of each line segment includes: setting a reference point at the same distance from any endpoint on the same side on each line segment; obtaining the weights corresponding to the first translation amount and the second translation amount of each line segment based on the edge placement error corresponding to each of the first and second correction results, and the vertical distance between the reference point and the boundary between the first region and the second region; the step of obtaining the weights corresponding to the first translation amount and the second translation amount of each line segment includes: constructing a first function with the edge placement error as a variable; constructing a second function with the vertical distance between the reference point and the boundary between the first region and the second region as a variable; weighting the first function and the second function to obtain the weights corresponding to each of the first translation amount and the second translation amount.

12. A photomask, characterized in that, include: The image obtained using the optical proximity correction method as described in any one of claims 1-10.

13. A device, characterized in that, It includes at least one memory and at least one processor, the memory storing one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the optical proximity correction method as described in any one of claims 1-10.

14. A storage medium, characterized in that, The storage medium stores one or more computer instructions for implementing the optical proximity correction method as described in any one of claims 1-10.

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