Optical Proximity Correction Method and System, Mask, Equipment and Storage Medium

Abstract

An optical proximity correction method and system, mask, device, and storage medium are disclosed. The optical proximity correction method includes: providing a target pattern; dividing the edge of the target pattern into multiple first line segments, including two endpoints and a first sampling point located between the two endpoints; performing a first optical proximity correction process on the target pattern using the first line segments to form a first initial corrected pattern and a corresponding first simulation pattern; determining whether the edge placement error of the first simulation pattern at the endpoint meets the correction standard; if the correction standard is not met, establishing a second sampling point at the endpoint, cutting off a portion of the length of the first line segment on both sides of the second sampling point and translating it to the target position to form a second line segment, with the remaining first line segment serving as a third line segment to form a second initial corrected pattern; and performing a second optical proximity correction process on the second initial corrected pattern using the second and third line segments to form a mask pattern. The present invention improves the effectiveness of optical proximity correction.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of semiconductor manufacturing, and in particular to an optical proximity correction method and system, a mask, a device, and a storage medium. Background Art

[0002] To transfer a pattern from a mask to the surface of a silicon wafer, it typically requires an exposure step, a development step that follows the exposure step, and an etching step that follows the development step. During the exposure step, light passes through the light-transmitting areas of the mask onto the silicon wafer coated with photoresist, causing the photoresist to undergo a chemical reaction under the irradiation of light. During the development step, the different solubility of the developer in the sensitive and unsensitive photoresists is exploited to form a photoresist pattern, enabling the transfer of the pattern from the mask to the photoresist. In the etching step, the silicon wafer is etched based on the photoresist pattern formed in the photoresist layer, further transferring the mask pattern to the silicon wafer.

[0003] However, as device sizes continue to shrink, the discrepancy between the chip surface pattern and the original mask pattern increases after the photolithography process. To prevent inconsistencies between the chip pattern and the mask pattern caused by the optical proximity effect, the current solution is to perform optical proximity correction (OPC) on the mask pattern and then transfer the pattern based on the corrected mask pattern. During the OPC correction process, a mask manufacturing rule check is often required to ensure the final pattern convergence and mask production accuracy.

[0004] However, the effectiveness of optical proximity correction still needs to be improved. 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, a mask, a device and a storage medium to improve the effect of optical proximity correction.

[0006] To solve the above problem, an embodiment of the present invention provides an optical proximity correction method, comprising: providing a target graphic; dividing the edge corresponding to the contour of the target graphic into a plurality of first line segments connected in sequence, wherein the first line segment includes two endpoints and a first sampling point located between the two endpoints; performing a first optical proximity correction process on the target graphic using the plurality of first line segments until the absolute value of the edge placement error at the first sampling point is within a first threshold range, thereby forming a first initial corrected graphic and a first simulated graphic corresponding to the first initial corrected graphic; determining whether the edge placement error of the first simulated graphic at each endpoint position meets the correction standard; and when the edge placement error of the first simulated graphic at the endpoint position meets the correction standard, the first initial corrected graphic is corrected. The corrected pattern is used as a mask pattern; when the edge placement error of the first simulation pattern at the endpoint position does not meet the correction standard, a second sampling point is set at the endpoint position, and among the adjacent first line segments on both sides of the second sampling point, a portion of the first line segment between adjacent first sampling points is intercepted and translated to a target position to form a second line segment, the second sampling point is located on the second line segment, and the remaining first line segments are used as third line segments, and the third line segments are alternately arranged with the second line segments to form a second initial corrected pattern; a second optical proximity correction process is performed on the second initial corrected pattern using the plurality of second line segments and the third line segments until the absolute values of the edge placement errors at the first sampling point and the second sampling point are both within a second threshold range, thereby forming a mask pattern.

[0007] Accordingly, an embodiment of the present invention further provides an optical proximity correction system, comprising: a providing unit for providing a target graphic; a first segmenting unit for segmenting the edges corresponding to the contour of the target graphic into a plurality of first line segments connected in sequence, wherein the first line segment comprises two endpoints and a first sampling point located between the two endpoints; a first optical proximity correction unit for performing a first optical proximity correction process on the target graphic using the plurality of first line segments until the absolute value of the edge placement error at the first sampling point is within a first threshold range, thereby forming a first initial corrected graphic and a first simulation graphic corresponding to the first initial corrected graphic; a judging unit for judging whether the edge placement error of the first simulation graphic at each of the endpoint positions reaches a correction standard, and when the edge placement error of the first simulation graphic at the endpoint position reaches the correction standard, The first initial corrected pattern is used as a mask pattern; a second segmentation unit is configured to, when an edge placement error of the first simulation pattern at the endpoint position does not meet a correction standard, establish a second sampling point at the endpoint position, and, among adjacent first line segments on both sides of the second sampling point, intercept a portion of the first line segment between adjacent first sampling points and translate the portion to a target position to form a second line segment, wherein the second sampling point is located on the second line segment, and the remaining first line segments serve as third line segments, and the third line segments are alternately arranged with the second line segments to form a second initial corrected pattern; and a second optical proximity correction unit is configured to perform a second optical proximity correction process on the second initial corrected pattern using the plurality of second and third line segments until the absolute values of the edge placement errors at the first and second sampling points fall within a second threshold range, thereby forming a mask pattern.

[0008] Correspondingly, an embodiment of the present invention further provides a mask, including a pattern obtained by using the optical proximity correction method provided by an embodiment of the present invention.

[0009] Accordingly, an embodiment of the present invention also provides a device comprising at least one memory and at least one processor, wherein the memory stores one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the optical proximity correction method provided in an embodiment of the present invention.

[0010] Correspondingly, an embodiment of the present invention further provides a storage medium, wherein the storage medium stores one or more computer instructions, and the one or more computer instructions are used to implement the optical proximity correction method provided by the embodiment of the present invention.

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

[0012] In the optical proximity correction method provided by an embodiment of the present invention, when the edge placement error of the first simulated figure at the endpoint position does not meet the correction standard, a second sampling point is established at the endpoint position, and among the adjacent first line segments on both sides of the second sampling point, a portion of the first line segment between adjacent first sampling points is intercepted and translated to a target position to form a second line segment, the second sampling point is located on the second line segment, and the remaining first line segments serve as third line segments. The third line segments are alternately arranged with the second line segments to form a second initial corrected figure, and a second optical proximity correction process is performed on the second initial corrected figure using the plurality of second and third line segments until the absolute values of the edge placement errors at the first and second sampling points are both within a second threshold range. A mask pattern is formed within the mask. Compared to a scheme that uses only a plurality of first line segments to perform optical proximity correction on the target pattern, in embodiments of the present invention, the plurality of second and third line segments are used to perform a second optical proximity correction on the first initially corrected pattern. This further refines the edges that can be used to perform the second optical correction on the first corrected pattern, thereby improving the accuracy of the second optical correction. Furthermore, compared to a scheme that uses only first sampling points, embodiments of the present invention provide more and denser first and second sampling points, such that the absolute values of edge placement errors at the first and second sampling points are both within a second threshold range. This helps reduce edge placement errors across the entire pattern and improves critical dimension uniformity (CDU) across the entire pattern. For example, this can alleviate the problem of ripple defects that are prone to occur in the first simulated pattern, thereby enhancing the effectiveness of optical proximity correction and correspondingly improving the matching degree between the mask pattern formed on the wafer and the target pattern. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 is a flow chart of an optical proximity correction method;

[0014] Figures 2 to 5 is a schematic diagram corresponding to each step in an optical proximity correction method;

[0015] Figure 6 is a flow chart of an embodiment of an optical proximity correction method of the present invention;

[0016] Figures 7 to 17 1 is a schematic diagram corresponding to each step in an embodiment of an optical proximity correction method of the present invention;

[0017] Figure 18 is a functional block diagram of an embodiment of an optical proximity correction system of the present invention;

[0018] Figure 19It is a hardware structure diagram of an embodiment of the device provided by the present invention. DETAILED DESCRIPTION

[0019] At present, the effect of optical proximity correction needs to be improved. This paper analyzes the reasons why the effect of optical proximity correction needs to be improved by combining an optical proximity correction method.

[0020] Figure 1 This is a flow chart of an optical proximity correction method. Figures 2 to 5 , shows a schematic diagram corresponding to each step in the optical proximity correction method, the optical proximity correction method comprising:

[0021] refer to Figure 2 , Figure 2 1 is a schematic diagram corresponding to step s1 , step s1 : providing a target graphic 10 .

[0022] refer to Figure 3 , Figure 3 s2 is a schematic diagram corresponding to step s2, step s2: dividing the edge corresponding to the outline of the target graphic 10 into a plurality of sequentially connected line segments 11, wherein the line segment 11 includes two endpoints A and a sampling point B located between the two endpoints A.

[0023] Combined with reference Figure 4 and Figure 5 , Figure 4 and Figure 5 This is a schematic diagram corresponding to step s3. Step s3: Using the multiple line segments 11, the target pattern 10 is subjected to optical proximity correction processing until the absolute value of the edge placement error (EPE) at the sampling point B is within a threshold range, thereby forming a mask pattern 21 and a mask simulation pattern 31 corresponding to the mask pattern 21.

[0024] in, Figure 5 The dotted line in represents the position of the target pattern 10.

[0025] In the semiconductor field, edge placement error is an indicator used to measure the quality of correction. The smaller the absolute value of the edge placement error, the closer the exposed pattern is to the designed pattern. During the correction process, in order to reduce the arbitrariness of edge movement, the edge placement error is reduced by moving the line segment 11. However, the sizes of the edge placement errors at the positions of the sampling points B on different line segments 11 vary. When the line segments 11 are moved, the movement distances of different line segments 11 differ greatly, which can easily lead to the edge placement error being within the threshold range at the position of the sampling point B, but being larger at the position of the endpoint A of the line segment 11. Moreover, on the line segment 11, the endpoint A is located on both sides of the sampling point B, which can easily lead to the edge placement errors at the positions of the two endpoints A of the line segment 11 being opposite in positive and negative values (such as Figure 5 As shown in A1 and A2 in FIG, the overall size uniformity of the pattern is poor, and the mask simulation pattern 31 is prone to produce ripple-shaped defects, thereby affecting the effect of optical proximity correction.

[0026] In order to solve the above technical problems, an embodiment of the present invention provides an optical proximity correction method. Figure 6 , which shows a flow chart of an embodiment of the optical proximity correction method of the present invention.

[0027] In this embodiment, the optical proximity correction method includes the following basic steps:

[0028] Step S1: providing a target graphic;

[0029] Step S2: dividing the edge corresponding to the outline of the target graphic into a plurality of sequentially connected first line segments, wherein the first line segment includes two endpoints and a first sampling point located between the two endpoints;

[0030] Step S3: performing a first optical proximity correction process on the target pattern using the plurality of first line segments until the absolute value of the edge placement error at the first sampling point is within a first threshold range, thereby forming a first initial corrected pattern and a first simulated pattern corresponding to the first initial corrected pattern;

[0031] Step S4: determining whether the edge placement error of the first simulation pattern at each endpoint position meets the correction standard;

[0032] Step S5: when the edge placement error of the first simulation pattern at the endpoint position reaches the correction standard, the first initial corrected pattern is used as the mask pattern;

[0033] Step S6: When the edge placement error of the first simulation figure at the endpoint position does not meet the correction standard, a second sampling point is set at the endpoint position, and among the adjacent first line segments on both sides of the second sampling point, a portion of the first line segment between the adjacent first sampling points is intercepted and translated to the target position to form a second line segment, the second sampling point is located on the second line segment, and the remaining first line segments serve as third line segments. The third line segments are alternately arranged with the second line segments to form a second initial corrected figure;

[0034] Step S7: performing a second optical proximity correction process on the second initially corrected pattern using the plurality of second line segments and third line segments until the absolute values of the edge placement errors at the first sampling point and the second sampling point are both within a second threshold range, thereby forming a mask pattern.

[0035] Compared to a scheme that uses only a plurality of first line segments to perform optical proximity correction on the target pattern, this embodiment uses the plurality of second and third line segments to perform a second optical proximity correction on the first initially corrected pattern. This further refines the edges that can be used to perform the second optical correction on the first corrected pattern, thereby improving the accuracy of the second optical correction. Furthermore, compared to a scheme that uses only first sampling points, this embodiment provides more and denser first and second sampling points, ensuring that the absolute values of edge placement errors at the first and second sampling points are both within a second threshold range. This helps reduce edge placement errors across the entire pattern and improves overall dimensional uniformity. For example, it can alleviate the ripple-shaped defects that are prone to occurring in the first simulated pattern, thereby enhancing the effectiveness of optical proximity correction and correspondingly improving the matching between the mask pattern formed on the wafer and the target pattern.

[0036] In order to make the above-mentioned objects, features and advantages of the embodiments of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0037] Figures 7 to 17 1 is a schematic diagram corresponding to each step in an embodiment of the optical proximity correction method of the present invention.

[0038] refer to Figure 7 , executing step S1: providing a target graphic 100.

[0039] The target pattern 100 refers to a design pattern and is used as a reference for edge placement errors of exposure patterns obtained by photolithography simulation.

[0040] After optical proximity correction is performed on the target pattern 100 , the obtained pattern is used to make a mask, and then a photolithography process is performed using the mask to form a corresponding mask pattern on a wafer.

[0041] In this embodiment, in the step of providing the target pattern 100, the extension direction of the target pattern 100 is the first direction (eg Figure 7 The target graphic 100 has an edge extending along the first direction.

[0042] In the semiconductor field, due to mask making constraints (MRC), the correction amount for the longer edges of line graphics near corners and line ends is usually large. Therefore, in this embodiment, optical proximity correction processing is performed on the target graphic 100 having edges extending along the first direction, which is beneficial to significantly improve the optical proximity effect.

[0043] In this embodiment, the target graphic 100 extends along a first direction, and the target graphic 100 is a line graphic. Subsequently, the edges corresponding to the outline of the target graphic 100 are divided into first line segments with a certain length. The outline of the target graphic 100 has edges extending along the first direction, and the edges extending along the first direction are mainly divided.

[0044] refer to Figure 8 , executing step S2: dividing the edge corresponding to the outline of the target graphic 100 into a plurality of sequentially connected first line segments 101, wherein the first line segment 101 includes two endpoints P and a first sampling point S1 located between the two endpoints P.

[0045] In the subsequent optical proximity correction process of the target pattern 100, in order to reduce the arbitrariness of edge movement, the edge placement error is reduced by adjusting the position of the line segment (for example, translating the line segment). In this embodiment, the position of the first line segment 101 is subsequently adjusted for optical proximity correction.

[0046] In this embodiment, in the step of dividing the edges corresponding to the outline of the target graphic 100 into multiple first line segments 101, the edges of the target graphic 100 extending along the first direction are divided into multiple first line segments 101, and accordingly, the extension direction of the first line segments 101 is also the first direction.

[0047] It should be noted that the length of the first line segment 101 should not be too large or too small. If the length of the first line segment 101 is too large, the edge corresponding to the target pattern 100's outline is divided into too few first line segments 101, and the number of corresponding first sampling points S1 is also too small, affecting the accuracy of subsequent optical proximity correction using the first line segment 101. If the length of the first line segment 101 is too small, the edge corresponding to the target pattern 100's outline is divided into too many first line segments 101, and the number of corresponding first sampling points S1 is also too large, which excessively increases the computational complexity of subsequent optical proximity correction. Moreover, if the first line segment 101 needs to be split again, the length of the first line segment 101 is too small, resulting in a large number of second and third line segments after the split, further increasing the computational complexity of subsequent optical proximity correction. Furthermore, the lengths of the second and third line segments are also likely to be too small. Based on the mask writing rule, this may make the target pattern after the second optical proximity correction process less friendly to mask writing, making it difficult to write the target pattern into the mask. Furthermore, the target pattern's edges may become more fragmented, increasing the cost of mask manufacturing. To this end, in this embodiment, the length of the first line segment 101 is 40 nm to 200 nm.

[0048] The first sampling point S1 is used as a specific position for comparing the difference between the target pattern 100 and the first simulated pattern after exposure, thereby obtaining an edge position error for determining whether the optical proximity correction is completed.

[0049] At the same time, the first line segment 101 is subsequently moved by calculating the edge position error at the position of the first sampling point S1. Therefore, each of the first line segments 101 includes the first sampling point S1.

[0050] In this embodiment, in the step of dividing the edge corresponding to the outline of the target graphic 100 into a plurality of first line segments 101 , the first sampling point S1 is located at the center of the corresponding first line segment 101 , which is intuitive, easy to detect and simple to operate.

[0051] It should be noted that when correcting a longer extending edge in a line graphic, it is usually more difficult to correct the edge near the end of the line graphic, and the correction amount is larger. Therefore, in this embodiment, in the step of dividing the edge of the target graphic 100 extending along the first direction into multiple first line segments 101, the length of the first line segment 101 near the end of the graphic is smaller, and the length of the first line segment 101 away from the end of the line graphic is larger.

[0052] Combined with reference Figures 9 to 11, executing step S3: performing a first optical proximity correction process on the target pattern 100 using the plurality of first line segments 101 until the absolute value of the edge placement error E1 at the first sampling point S1 is within a first threshold range, thereby forming a first initial corrected pattern 210 and a first simulated pattern 310 corresponding to the first initial corrected pattern 210.

[0053] The first initial corrected pattern 210 may be used as a target pattern, and the first simulation pattern 110 may be used as a target simulation pattern; or, the first initial corrected pattern 210 may also be used as a basis for a subsequent second optical proximity correction process.

[0054] In this embodiment, a model-based optical proximity correction (MB-OPC) process is used to perform a first optical proximity correction (OPC) on the target pattern 100. During the correction process, an optical model and a photoresist photochemical reaction model are used to calculate an initial simulated pattern of the target pattern 100 after exposure. The model-based OPC process identifies the edges corresponding to the outline of the target pattern 100. The initial simulated pattern after exposure is compared with the identified outline of the target pattern 100. The difference between the two is called the edge placement error (EPE). The edge placement error is used to measure the correction quality. The smaller the edge placement error, the closer the exposed pattern is to the target pattern 100.

[0055] In other embodiments, rule-based OPC, or a combination of model-based and rule-based OPC, may be used to perform the first OPC process. In other embodiments, other suitable OPC methods may also be used.

[0056] It should be noted that, at the first sampling point S1, when the edge placement error E1 of the first simulated graphic 310 is greater than 0, it indicates that the position corresponding to the first sampling point S1 in the first simulated graphic 310 is located outside the target graphic 100. When the edge placement error E1 of the first simulated graphic 310 is less than 0, it indicates that the position corresponding to the first sampling point S1 in the first simulated graphic 310 is located inside the target graphic 100. When the edge placement error E1 of the first simulated graphic 310 is equal to 0, it indicates that the position corresponding to the first sampling point S1 in the first simulated graphic 310 is located on the target graphic 100. The edge placement error E1 at the first sampling point S1 can be either positive or negative, as long as the absolute value of E1 is within the first threshold range.

[0057] It should be noted that the first threshold range should not be too large or too small. If the first threshold range is too large, then when the absolute value of the edge placement error E1 at the first sampling point S1 is within the first threshold range, the difference between the outlines of the first simulated pattern 310 and the target pattern 100 is still significant, making it difficult to achieve the correction effect of the optical proximity correction. If the first threshold range is too small, the correction accuracy of the first optical proximity correction process is increased to an unnecessary high level, significantly increasing the computational complexity of the first optical proximity correction process and making the correction process difficult. To this end, in this embodiment, in the step of performing the first optical proximity correction process on the target pattern 100 using multiple first line segments 101, the first threshold range is 0.1 nm to 0.5 nm.

[0058] Specifically, refer to Figure 9 The step of performing a first optical proximity correction process on the target pattern 100 using the plurality of first line segments 101 includes: performing one or more first correction operations until the absolute value of the edge placement error E1 is within the first threshold range.

[0059] The iterative processing of the first correction operation cycle is performed multiple times until the edge placement error E1 at the first sampling point S1 converges, that is, the absolute value of the edge placement error E1 is within the first threshold range.

[0060] refer to Figure 9 The first correction operation includes: performing simulated exposure on the target pattern 100 to obtain an initial simulated pattern 110.

[0061] The initial simulation pattern 110 is used to compare with the target pattern 100 to obtain an edge placement error corresponding to the simulated exposure pattern.

[0062] Continue to refer Figure 9 , calculate the edge placement error E1 of the initial simulation graphic 110 at the position of the first sampling point S1.

[0063] Correspondingly, at the position of the first sampling point S1, when the edge placement error E1 of the initial simulation graphic 110 is greater than 0, it indicates that the initial simulation graphic 110 is located outside the target graphic 100; when the edge placement error E1 of the initial simulation graphic 110 is less than 0, it indicates that the initial simulation graphic 110 is located inside the target graphic 100; and when the edge placement error E1 of the initial simulation graphic 110 is equal to 0, it indicates that the initial simulation graphic 110 is located on the target graphic 100.

[0064] refer to Figure 10, adjusting the position of the first line segment 101 according to the edge placement error E1.

[0065] Specifically, along the direction perpendicular to the first line segment 101, when the edge placement error E1 is greater than 0, the step of adjusting the position of the first line segment 101 includes: moving the corresponding first line segment 101 into the target graphic 100; when the edge placement error E1 is less than 0, the step of adjusting the position of the first line segment 101 includes: moving the corresponding first line segment 101 out of the target graphic 100; when the edge placement error E1 is equal to 0, the step of adjusting the position of the first line segment 101 includes: maintaining the position of the corresponding first line segment 101, that is, not moving the first line segment 101.

[0066] It should be noted that after performing a first correction operation, in the next first correction operation in the iterative loop, the target pattern 100 obtained by moving the first line segment 101 in the previous first correction operation is used as the target pattern 100 for simulated exposure. In other words, the target pattern 100 obtained by adjusting the position of the first line segment 101 is used as the target pattern 100 for simulated exposure in the next first correction operation.

[0067] Among them, when the absolute value of the edge placement error E1 of the initial simulation figure 110 is within the first threshold range, the target figure 100 after adjusting the position of the first line segment 101 is used as the first initial corrected figure 210, and the initial simulation figure 110 is used as the first simulation figure 310.

[0068] refer to Figure 11 , executing step S4: determining whether the edge placement error of the first simulation graphic 310 at each of the endpoints P reaches a correction standard.

[0069] Determine whether the edge placement error of the first simulation graphic 310 at each endpoint P position meets the correction standard, and then take measures based on the judgment result so that the first simulation graphic 310 at each endpoint P position can meet the correction standard.

[0070] Specifically, the step of determining whether the edge placement error of the first simulation graphic 310 at each endpoint P position meets the correction standard includes determining whether the edge placement error of the first simulation graphic 310 at each endpoint P position meets a first preset condition, where the first preset condition is:

[0071] δ1×δ2<0, where δ1 is the edge placement error of the first simulation graphic 310 at any endpoint P of the first line segment 101, and δ2 is the edge placement error of the first simulation graphic 310 at the other endpoint P of the first line segment 101.

[0072] Specifically, at the endpoint P, when the edge placement error of the first simulated graphic 310 is greater than 0, it means that the first simulated graphic 310 is located outside the target graphic 100; when the edge placement error of the first simulated graphic 310 is less than 0, it means that the first simulated graphic 310 is located inside the target graphic 100; when the edge placement error of the first simulated graphic 310 is equal to 0, it means that the first simulated graphic 310 is located on the target graphic 100, then δ1×δ2<0, indicating that the first simulated graphic 310 passing through the two end points P of the first line segment 101 is wavy in shape, which may affect the overall size uniformity of the graphic, that is, the effect of the first optical proximity correction processing may be poor.

[0073] Therefore, when the edge placement error of the first simulation graphic 310 at each of the endpoints P does not meet the first preset condition, the edge placement error of the first simulation graphic 310 reaches the correction standard, that is, the effect of the first optical proximity correction processing is better.

[0074] When the edge placement error of the first simulation graphic 310 at each of the endpoints P meets the first preset condition, the edge placement error of the first simulation graphic 310 at the endpoints P may not meet the correction standard, and further determination is required as to whether a second optical proximity correction process is required.

[0075] In this embodiment, when the edge placement error of the first analog graphic 310 at each of the endpoints P satisfies the first preset condition, it is determined whether the edge placement error of the first analog graphic 310 at each of the endpoints P satisfies the second preset condition. The second preset condition is: |δ1-δ2|>preset value, and the preset value is 5nm to 10nm.

[0076] Here, |δ1−δ2| represents the distance between the first simulation pattern 310 at the two end points P of the first line segment 101 along a direction perpendicular to the first line segment 101 .

[0077] When |δ1-δ2| is small, although the first simulated figure 310 has a wavy morphology, the wavy morphology is small, and the size uniformity of the first simulated figure 310 is still good. However, when the value of |δ1-δ2| is large, it means that the first simulated figure 310 passing through the two end points P of the first line segment 101 not only has a wavy morphology, but also has a large wavy morphology, and the overall size uniformity of the figure is poor. In other words, the effect of the first optical proximity correction processing is not good.

[0078] Therefore, when the edge placement error of the first simulation graphic 310 at each of the endpoints P does not meet the second preset condition, the edge placement error of the first simulation graphic 310 reaches the correction standard, that is, the effect of the first optical proximity correction processing is better.

[0079] When the edge placement error of the first simulation graphic 310 at each of the endpoints P meets the second preset condition, the edge placement error of the first simulation graphic 310 at the endpoints P does not meet the correction standard, and a second optical proximity correction process is required.

[0080] It should be noted that the preset value should not be too large or too small. If the preset value is too large, when the value of |δ1-δ2| is less than or equal to the preset value but still large, a second optical proximity correction process should be performed. However, according to the preset conditions, this process is not necessary, affecting the correction result of the target pattern 100. If the preset value is too small, when the preset conditions are too stringent, it is easy to cause an unnecessary second optical proximity correction process even when the effect of the first optical proximity correction process is acceptable, thereby reducing the efficiency of the optical proximity correction. To this end, in this embodiment, the preset value is 5nm to 10nm.

[0081] In this embodiment, when the above-mentioned first preset condition and second preset condition are met at the same time, it is determined that the edge placement error of the first simulated figure does not reach the correction standard. When the first preset condition is not met, there is no need to judge the second preset condition, and it is determined that the edge placement error of the first simulated figure reaches the correction standard. When the first preset condition is met but the second preset condition is not met, it is determined that the edge placement error of the first simulated figure reaches the correction standard.

[0082] Moreover, in this embodiment, only when the edge placement error of the first simulation graphic 310 satisfies the first preset condition is it further determined that the edge placement error of the first simulation graphic 310 satisfies the second preset condition. This is beneficial for improving the correction accuracy by utilizing the second optical proximity correction processing while reducing the amount of calculation for determining whether the edge placement error of the first simulation graphic 310 at each endpoint P position meets the correction standard, thereby improving calculation efficiency.

[0083] When the edge placement error of the first simulation pattern 310 at the end point P reaches the correction standard, step S5 is executed: the first initial corrected pattern 210 is used as a mask pattern.

[0084] Combined with reference Figure 12 and Figure 13 When the edge placement error of the first simulation graphic 310 at the endpoint P reaches the correction standard, step S6 is executed.

[0085] A second sampling point S2 is established at the endpoint P. Among the adjacent first line segments 101 on both sides of the second sampling point S2, a portion of the first line segment 101 between the adjacent first sampling points S1 is intercepted and translated to a target position to form a second line segment 102. The second sampling point S2 is located on the second line segment 102. The remaining first line segments 101 serve as third line segments 103. The third line segments 103 are alternately arranged with the second line segments 102 to form a second initial corrected graph 220.

[0086] Compared to a scheme that uses only a plurality of first line segments to perform optical proximity correction on the target pattern, in this embodiment, the plurality of second line segments 102 and third line segments 103 are used to perform a second optical proximity correction on the first initial corrected pattern 210. This further refines the edges that can be used to perform the second optical correction on the first corrected pattern 210, thereby improving the accuracy of the second optical correction. Furthermore, compared to a scheme that uses only first sampling points, this embodiment provides a greater number of first sampling points S1 and second sampling points S2, which are denser. After the subsequent optical proximity correction, the absolute values of the edge placement errors at the first sampling points S1 and the second sampling points S2 are both within a second threshold range. This helps reduce the edge placement error of the entire pattern and improves the overall dimensional uniformity of the pattern. For example, it can alleviate the problem of ripple-shaped defects that are prone to occur in the first simulated pattern 310, thereby enhancing the effectiveness of optical proximity correction and correspondingly improving the matching degree between the mask pattern formed on the wafer and the target pattern.

[0087] It should be noted that, based on the mask writing rule, the minimum length of the second line segment 102 should not be too small, so that the target pattern after the subsequent second optical proximity correction process is highly mask-write-friendly and can be produced in the mask. To this end, in this embodiment, the minimum length of the second line segment 102 is 20 nm.

[0088] It should also be noted that the length of the second line segment 102 should not be too long or too short. If the length of the second line segment 102 is too long, the length of the remaining first line segment 101 will be too short. In other words, the length of the third line segment 103 will be too short, increasing the computational load for the subsequent second optical proximity correction process. Furthermore, a smaller third line segment 103 will likely result in more fragmented edges on the target pattern, increasing the cost of mask manufacturing. If the length of the second line segment 102 is too short, it will be difficult to write the target pattern. Furthermore, a shorter second line segment 102 will increase the computational load for the subsequent second optical proximity correction process. Furthermore, a smaller second line segment 102 will likely result in more fragmented edges on the target pattern, increasing the cost of mask manufacturing. Therefore, in this embodiment, the length of the second line segment 102 is 20 nm to 40 nm.

[0089] In this embodiment, among the adjacent first line segments 101 on both sides of the second sampling point S2, the first line segments 101 of equal length between adjacent first sampling points S1 are respectively intercepted and translated to the target position to form the second line segment 102. The second sampling point S2 is located at the center of the second line segment 102, which is intuitive, easy to detect, and simple to operate.

[0090] refer to Figure 13 , the target position is adjacent to the first line segment 101 in the second direction (such as Figure 13 At a middle position on the line segment 101 (as shown in the Y direction), the second direction is perpendicular to the first direction, that is, the second direction is perpendicular to the extension direction of the first line segment 101.

[0091] The second line segment 102 is formed at a middle position adjacent to the first line segment 101 in the second direction, which is conducive to obtaining a second initial corrected pattern 220 with better pattern uniformity.

[0092] Combined with reference Figures 14 to 16 , executing step S7: using multiple second line segments 102 and third line segments 103, performing a second optical proximity correction process on the second initial corrected pattern 220 until the absolute values of the edge placement errors at the first sampling point S1 and the second sampling point S2 are both within a second threshold range, thereby forming a mask pattern 230.

[0093] In this embodiment, a model-based optical proximity correction process is used to perform the second optical proximity correction process on the second initial corrected pattern 220. In other embodiments, an empirical rule-based optical proximity correction process, or a hybrid of a model-based and empirical rule-based optical proximity correction process, may also be used to perform the second optical proximity correction process. In still other embodiments, other suitable optical proximity correction processing methods may also be used.

[0094] In this embodiment, a mask simulation pattern 330 corresponding to the mask pattern 230 is formed accordingly. It should be noted that, at the first sampling point S1, when the edge placement error E2 is greater than 0, it indicates that the target simulation pattern 330 is located outside the target pattern 100; when the edge placement error E2 of the target simulation pattern 330 is less than 0, it indicates that the target simulation pattern 330 is located inside the target pattern 100; and when the edge placement error E2 of the target simulation pattern 330 is equal to 0, it indicates that the target simulation pattern 330 is located on the target pattern 100. The same applies to the second sampling point S2. The edge placement errors E2 and E3 at the first sampling point S1 and the second sampling point S2 can be positive or negative, as long as the absolute values of E2 and E3 are both within the second threshold range.

[0095] It should be noted that the second threshold range should not be too large or too small. If the second threshold range is too large, when the absolute values of the edge placement errors E2 and E3 at the first sampling point S1 and the second sampling point S2 are both within the second threshold range, the target simulated pattern 330 and the target pattern 100 still differ significantly in their contours, making it difficult to achieve the correction effect of the second optical proximity correction process. If the second threshold range is too small, the correction accuracy of the second optical proximity correction process is increased to an unnecessary high level, significantly increasing the computational complexity of the second optical proximity correction process and making the correction process difficult. To this end, in this embodiment, in the step of performing the second optical proximity correction process on the second initial corrected pattern 220 using multiple second line segments 102 and third line segments 103, the second threshold range is 0.1 nm to 0.5 nm.

[0096] Specifically, refer to Figure 14 The step of performing a second optical proximity correction process on the second initially corrected pattern 220 using multiple second line segments 102 and third line segments 103 includes: performing one or more second correction operations until the absolute values of the edge placement errors E2 and E3 are both within the second threshold range.

[0097] The second correction operation cycle is iterated multiple times until the edge placement errors E2 and E3 at the first sampling point S1 and the second sampling point S2 converge, that is, the absolute values of the edge placement errors E2 and E3 are both within the second threshold range.

[0098] refer to Figure 14 The second correction operation includes: performing simulated exposure on the second initial corrected pattern 220 to obtain a second simulated pattern 320.

[0099] The second simulated pattern 320 is used to compare with the second initial corrected pattern 220 to obtain an edge placement error corresponding to the simulated exposure pattern.

[0100] Continue to refer Figure 14 , calculate edge placement errors E2 and E3 of the second simulation graphic 320 at the positions of the first sampling point S1 and the second sampling point S2.

[0101] Correspondingly, at the position of the first sampling point S1, when the edge placement error E2 of the second simulated graphic 320 is greater than 0, it means that the second simulated graphic 320 is located outside the target graphic 100; when the edge placement error E2 of the second simulated graphic 320 is less than 0, it means that the second simulated graphic 320 is located inside the target graphic 100; when the edge placement error E2 of the second simulated graphic 320 is equal to 0, it means that the second simulated graphic 320 is located on the target graphic 100. The same applies at the position of the second sampling point S2.

[0102] refer to Figure 15 , adjusting the positions of the second line segment 102 and the third line segment 103 according to the edge placement errors E2 and E3.

[0103] Specifically, along the second direction, when the edge placement error E2 is greater than 0, the step of adjusting the position of the second line segment 102 includes: moving the corresponding second line segment 102 into the target graphic 100; when the edge placement error E2 is less than 0, the step of adjusting the position of the second line segment 102 includes: moving the corresponding second line segment 102 out of the target graphic 100; when the edge placement error E2 is equal to 0, the step of adjusting the position of the second line segment 102 includes: maintaining the position of the corresponding second line segment 102, that is, not moving the second line segment 102. Correspondingly, the same applies to the edge placement error E3 and the corresponding third line segment 103.

[0104] It should be noted that after performing a second correction operation, in the next second correction operation in the iterative loop, the second initial corrected pattern 220 obtained by moving the second line segment 102 and the third line segment 103 in the previous second correction operation is used as the second initial corrected pattern 220 for simulated exposure. In other words, the target pattern 100 obtained by adjusting the position of the first line segment 101 is used as the target pattern 100 for simulated exposure in the next first correction operation.

[0105] Among them, when the absolute values of the edge placement errors E2 and E3 of the second simulation figure 320 are both within the second threshold range, the second initial corrected figure 220 after adjusting the positions of the second line segment 102 and the third line segment 103 is used as the mask figure 230, and the second simulation figure 320 is used as the mask simulation figure 330.

[0106] refer to Figure 17 After forming the mask pattern 230 , the method further includes: adding an auxiliary pattern 400 around the mask pattern 230 .

[0107] In this embodiment, the mask pattern 230 is an exposeable pattern, and the auxiliary pattern 400 is a non-exposeable pattern. To this end, the auxiliary pattern 400 is a scattering bar (SB), and the line width of the auxiliary pattern 400 is greater than or equal to the minimum line width of the mask writing rule, and less than or equal to the resolution of the photolithography process, so that the auxiliary pattern can be written into the template but will not be exposed.

[0108] Providing scattering strips around the mask pattern 230 is beneficial to improving light intensity contrast, reducing edge placement error (EPE), and also beneficial to increasing the depth of focus, thereby improving the photolithography process window.

[0109] In this embodiment, the optical proximity correction is performed twice, thereby improving the accuracy of the optical proximity correction, and the modification to the traditional optical proximity correction is relatively small, and the compatibility is relatively high.

[0110] Correspondingly, the present invention also provides an optical proximity correction system. Figure 18 FIG. 4 is a functional block diagram of an optical proximity correction system according to an embodiment of the present invention.

[0111] In this embodiment, the optical proximity correction system 50 includes: a providing unit 501 for providing a target graphic; a first segmenting unit 502 for segmenting an edge corresponding to a contour of the target graphic into a plurality of sequentially connected first line segments, wherein the first line segment includes two endpoints and a first sampling point located between the two endpoints; a first optical proximity correction unit 505 for performing a first optical proximity correction process on the target graphic using the plurality of first line segments until the absolute value of the edge placement error at the first sampling point is within a first threshold range, thereby forming a first initial corrected graphic and a first simulated graphic corresponding to the first initial corrected graphic; and a judging unit 506 for judging whether the edge placement error of the first simulated graphic at each endpoint position meets a correction standard, and when the edge placement error of the first simulated graphic at the endpoint position meets the correction standard, The first initial corrected pattern is used as a mask pattern. A second segmentation unit 507 is configured to, when an edge placement error of the first simulated pattern at the endpoint position does not meet a correction standard, establish a second sampling point at the endpoint position, and, from adjacent first line segments on both sides of the second sampling point, intercept a portion of the first line segment between adjacent first sampling points and translate the portion to a target position to form a second line segment. The second sampling point is located on the second line segment, and the remaining first line segments serve as third line segments. The third line segments are alternately arranged with the second line segments to form a second initial corrected pattern. A second optical proximity correction unit is configured to perform a second optical proximity correction process on the second initial corrected pattern using the plurality of second and third line segments until the absolute values of the edge placement errors at the first and second sampling points fall within a second threshold range, thereby forming a mask pattern.

[0112] The target pattern provided by the providing unit 501 refers to a design pattern, which is used as a reference benchmark for edge placement errors of exposure patterns obtained by photolithography simulation.

[0113] After optical proximity correction is performed on the target pattern, the obtained pattern is used to make a mask, and then a photolithography process is performed using the mask to form a corresponding mask pattern on a wafer.

[0114] In this embodiment, in the step of providing the target pattern, the extension direction of the target pattern is a first direction, and the outline of the target pattern has an edge extending along the first direction.

[0115] In the semiconductor field, due to the restrictions of mask manufacturability rules, the correction amount for the longer extending edges in the line graphics is usually large, near the corners and line end positions. Therefore, in this embodiment, optical proximity correction processing is performed on the target graphics having edges extending along the first direction, which is beneficial to significantly improve the optical proximity effect.

[0116] In this embodiment, the target graphic extends along a first direction, and the target graphic is a line graphic. Subsequently, the edge corresponding to the outline of the target graphic is divided into first line segments with a certain length. The outline of the target graphic has an edge extending along the first direction, and the edge extending along the first direction is mainly divided.

[0117] The first segmentation unit 502 is configured to segment the edge corresponding to the outline of the target graphic into a plurality of sequentially connected first line segments, where the first line segment includes two endpoints and a first sampling point located between the two endpoints.

[0118] In the subsequent optical proximity correction process of the target pattern, in order to reduce the arbitrariness of edge movement, the edge placement error is reduced by adjusting the position of the line segment (for example, translating the line segment). In this embodiment, the optical proximity correction is performed by subsequently adjusting the position of the first line segment.

[0119] In this embodiment, in the step of dividing the edge corresponding to the outline of the target graphic into multiple first line segments, the edge of the target graphic extending along the first direction is divided into multiple first line segments, and accordingly, the extension direction of the first line segments is also the first direction.

[0120] It should be noted that the length of the first line segment should not be too large or too small. If the length of the first line segment is too large, the edge corresponding to the target pattern's outline will be divided into too few first line segments, and the corresponding first sampling points will also be too few, affecting the accuracy of the subsequent optical proximity correction using the first line segment. If the length of the first line segment is too small, the edge corresponding to the target pattern's outline will be divided into too many first line segments, and the corresponding first sampling points will also be too many, excessively increasing the computational complexity of the subsequent optical proximity correction. Moreover, if the first line segment needs to be split again, the length of the first line segment will be too small, resulting in a large number of second and third line segments after the split, further increasing the computational complexity of the subsequent optical proximity correction. Furthermore, the length of the second and third line segments may be too small. Based on the mask writing rules, this may make the target pattern after the second optical proximity correction less friendly to the mask writing, making it difficult to write the target pattern into the mask. Furthermore, it may also lead to more fragmented edges of the target pattern, increasing the cost of mask manufacturing. To this end, in this embodiment, the length of the first line segment is 40 nm to 200 nm.

[0121] The first sampling point is used as a specific position for comparing the difference between the target pattern and the first simulated pattern after exposure, so as to obtain an edge position error for determining whether the optical proximity correction is completed.

[0122] At the same time, the first line segments are subsequently moved by calculating the edge position error at the position of the first sampling point. Therefore, each of the first line segments includes the first sampling point.

[0123] In this embodiment, in the step of dividing the edge corresponding to the outline of the target graphic into a plurality of first line segments, the first sampling point is located at the center of the corresponding first line segment, which is intuitive, easy to detect and simple to operate.

[0124] It should be noted that when correcting a longer extending edge in a line graphic, it is usually more difficult to correct the position near the end of the line graphic, and the correction amount is larger. Therefore, in this embodiment, in the step of dividing the edge of the target graphic extending along the first direction into multiple first line segments, the length of the first line segment near the end position of the graphic is smaller, and the length of the first line segment away from the end position of the line graphic is larger.

[0125] A first optical proximity correction unit 503 is configured to perform a first optical proximity correction process on the target pattern using the plurality of first line segments until the absolute value of the edge placement error at the first sampling point is within a first threshold range, thereby forming a first initial corrected pattern and a first simulated pattern corresponding to the first initial corrected pattern.

[0126] The first initial corrected pattern can be used as a target pattern, and the first simulation pattern can be used as a target simulation pattern; or, the first initial corrected pattern can also be used as a basis for a subsequent second optical proximity correction process.

[0127] In this embodiment, a model-based optical proximity correction process is used to perform a first optical proximity correction on the target pattern. During this correction process, an optical model and a photoresist photochemical reaction model are used to calculate an initial simulated pattern of the target pattern after exposure. The model-based optical proximity correction process identifies the edges corresponding to the target pattern's outline. The initial simulated pattern after exposure is compared with the identified target pattern outline, and the difference between them is called edge placement error. Edge placement error is used to measure the quality of the correction; a smaller edge placement error indicates that the exposed pattern is closer to the target pattern.

[0128] In other embodiments, the first optical proximity correction process may be performed using optical proximity correction based on empirical rules, or a combination of model-based and empirical rule-based optical proximity correction. In other embodiments, other suitable optical proximity correction methods may also be selected.

[0129] It should be noted that, at the first sampling point, when the edge placement error E1 of the first simulated figure is greater than 0, it indicates that the position corresponding to the first sampling point in the first simulated figure is located outside the target figure. When the edge placement error E1 of the position corresponding to the first sampling point in the first simulated figure is less than 0, it indicates that the position corresponding to the first sampling point in the first simulated figure is located inside the target figure. When the edge placement error E1 of the first simulated figure is equal to 0, it indicates that the first simulated figure is located on the target figure. The edge placement error E1 at the first sampling point can be a positive value or a negative value, as long as the absolute value of E1 is within the first threshold range.

[0130] It should be noted that the first threshold range should not be too large or too small. If the first threshold range is too large, then when the absolute value of the edge placement error E1 at the first sampling point falls within the first threshold range, the difference between the outlines of the first simulated pattern and the target pattern remains significant, making it difficult to achieve the correction effect of the optical proximity correction. If the first threshold range is too small, the correction accuracy of the first optical proximity correction process is increased to an unnecessary high level, significantly increasing the computational complexity of the first optical proximity correction process and making correction difficult. To this end, in this embodiment, in the step of performing the first optical proximity correction process on the target pattern using multiple first line segments, the first threshold range is 0.1 nm to 0.5 nm.

[0131] Specifically, the step of performing a first optical proximity correction process on the target pattern using the plurality of first line segments includes: performing one or more first correction operations until the absolute value of the edge placement error E1 is within the first threshold range.

[0132] The iterative processing of the first correction operation cycle is performed multiple times until the edge placement error E1 at the first sampling point converges, that is, the absolute value of the edge placement error E1 is within the first threshold range.

[0133] The first correction operation includes: performing simulated exposure on the target pattern to obtain an initial simulated pattern.

[0134] The initial simulation pattern is used to compare with the target pattern to obtain an edge placement error corresponding to the simulated exposure pattern.

[0135] An edge placement error E1 of the initial simulation pattern at the position of the first sampling point is calculated.

[0136] Correspondingly, at the position of the first sampling point, when the edge placement error E1 of the initial simulation figure is greater than 0, it indicates that the initial simulation figure is located outside the target figure; when the edge placement error E1 of the initial simulation figure is less than 0, it indicates that the initial simulation figure is located inside the target figure; when the edge placement error E1 of the initial simulation figure is equal to 0, it indicates that the initial simulation figure is located on the target figure.

[0137] The position of the first line segment is adjusted according to the edge placement error E1.

[0138] Specifically, along the direction perpendicular to the first line segment, when the edge placement error E1 is greater than 0, the step of adjusting the position of the first line segment includes: moving the corresponding first line segment into the target figure; when the edge placement error E1 is less than 0, the step of adjusting the position of the first line segment includes: moving the corresponding first line segment outside the target figure; when the edge placement error E1 is equal to 0, the step of adjusting the position of the first line segment includes: maintaining the position of the corresponding first line segment, that is, not moving the first line segment.

[0139] It should be noted that after performing a first correction operation, in the next first correction operation in the iterative loop, the target pattern obtained by moving the first line segment in the previous first correction operation is used as the target pattern for simulated exposure. In other words, the target pattern obtained by adjusting the position of the first line segment is used as the target pattern for simulated exposure in the next first correction operation.

[0140] When the absolute value of the edge placement error E1 of the initial simulation figure is within the first threshold range, the target figure after adjusting the position of the first line segment is used as the first initial corrected figure, and the initial simulation figure is used as the first simulation figure.

[0141] The judgment unit 504 is used to judge whether the edge placement error of the first simulated figure at each of the endpoint positions reaches the correction standard, and when the edge placement error of the first simulated figure at the endpoint position reaches the correction standard, the first initial corrected figure is used as the target figure.

[0142] Determine whether the edge placement error of the first simulation graphic at each of the endpoint positions meets the correction standard, and then take measures based on the determination result so that the first simulation graphic at each of the endpoint positions meets the correction standard.

[0143] Specifically, the step of determining whether the edge placement error of the first simulation figure at each endpoint position meets the correction standard includes determining whether the edge placement error of the first simulation figure at each endpoint position meets a first preset condition, where the first preset condition is:

[0144] δ1×δ2<0, where δ1 is the edge placement error of the first simulation figure at any endpoint of the first line segment, and δ2 is the edge placement error of the first simulation figure at the other endpoint of the first line segment.

[0145] Specifically, at the endpoints, when the edge placement error of the first simulated figure is greater than 0, it indicates that the first simulated figure is located outside the target figure; when the edge placement error of the first simulated figure is less than 0, it indicates that the first simulated figure is located inside the target figure; when the edge placement error of the first simulated figure is equal to 0, it indicates that the first simulated figure is located on the target figure, then δ1×δ2<0, indicating that the first simulated figure passing through the two endpoints of the first line segment is wavy, which may affect the overall size uniformity of the figure, that is, the effect of the first optical proximity correction processing may be poor.

[0146] Therefore, when the edge placement error of the first simulation pattern at each of the endpoint positions does not meet the first preset condition, the edge placement error of the first simulation pattern reaches the correction standard, that is, the effect of the first optical proximity correction processing is better.

[0147] When the edge placement error of the first simulated figure at each of the endpoint positions meets the first preset condition, the edge placement error of the first simulated figure at the endpoint position may not meet the correction standard, and further judgment is required as to whether a second optical proximity correction process is required.

[0148] In this embodiment, when the edge placement error of the first simulation figure at each of the endpoint positions meets the first preset condition, it is determined whether the edge placement error of the first simulation figure at each of the endpoint positions meets the second preset condition, and the second preset condition is: |δ1-δ2|>preset value, and the preset value is 5nm to 10nm.

[0149] Here, |δ1−δ2| represents the distance between the first simulation figure at the two end points of the first line segment along a direction perpendicular to the first line segment.

[0150] When |δ1-δ2| is small, although the first simulated figure has a wavy morphology, the wavy morphology is small, and the size uniformity of the first simulated figure is still good. However, when the value of |δ1-δ2| is large, it means that the first simulated figure passing through the two end points of the first line segment not only has a wavy morphology, but also has a large wavy morphology, and the overall size uniformity of the figure is poor. In other words, the effect of the first optical proximity correction processing is not good.

[0151] Therefore, when the edge placement error of the first simulation figure at each of the endpoint positions does not meet the second preset condition, the edge placement error of the first simulation figure reaches the correction standard, that is, the effect of the first optical proximity correction processing is better.

[0152] When the edge placement error of the first simulation figure at each of the endpoint positions meets the second preset condition, the edge placement error of the first simulation figure at the endpoint position does not meet the correction standard, and a second optical proximity correction process is required.

[0153] It should be noted that the preset value should not be too large or too small. If the preset value is too large, when the value of |δ1-δ2| is less than or equal to the preset value but still large, a second optical proximity correction process should be performed. However, according to the preset conditions, this process is not necessary, affecting the correction result of the target pattern. If the preset value is too small, when the preset conditions are too stringent, it is easy to cause an unnecessary second optical proximity correction process even when the effect of the first optical proximity correction process is acceptable, thereby reducing the efficiency of the optical proximity correction. To this end, in this embodiment, the preset value is 5nm to 10nm.

[0154] In this embodiment, when the above-mentioned first preset condition and second preset condition are met at the same time, it is determined that the edge placement error of the first simulated figure does not reach the correction standard. When the first preset condition is not met, there is no need to judge the second preset condition, and it is determined that the edge placement error of the first simulated figure reaches the correction standard. When the first preset condition is met but the second preset condition is not met, it is determined that the edge placement error of the first simulated figure reaches the correction standard.

[0155] Moreover, in this embodiment, only when the edge placement error of the first simulated figure satisfies the first preset condition is it further determined that the edge placement error of the first simulated figure satisfies the second preset condition. This is beneficial for improving the correction accuracy by utilizing the second optical proximity correction processing while reducing the amount of calculation for determining whether the edge placement error of the first simulated figure at each endpoint position meets the correction standard, thereby improving calculation efficiency.

[0156] When the edge placement error of the first simulation pattern at the endpoint position reaches a correction standard, the first initial corrected pattern is used as a mask pattern.

[0157] When the edge placement error of the first simulation figure at the endpoint position reaches the correction standard, the process enters the second segmentation unit 505 .

[0158] The second segmentation unit 505 is configured to, when the edge placement error of the first simulated figure at the endpoint position does not meet the correction standard, establish a second sampling point at the endpoint position, intercept a portion of the first line segment between adjacent first sampling points on both sides of the second sampling point, and translate the portion to a target position to form a second line segment. The second sampling point is located on the second line segment, and the remaining first line segments serve as third line segments. The third line segments are alternately arranged with the second line segments to form a second initial corrected figure.

[0159] Compared to a scheme that uses only a plurality of first line segments to perform optical proximity correction on the target pattern, in this embodiment, the plurality of second and third line segments are used to perform a second optical proximity correction on the first initially corrected pattern. In other words, the edges that can be used to perform the second optical correction on the first corrected pattern are further refined, thereby improving the accuracy of the second optical correction. Furthermore, compared to a scheme that uses only first sampling points, this embodiment provides more and denser first and second sampling points. After subsequent optical proximity correction, the absolute values of the edge placement errors at the first and second sampling points are both within a second threshold range, which helps reduce the edge placement error of the overall pattern and improves the overall dimensional uniformity of the pattern. For example, it can alleviate the problem of ripple-shaped defects that are prone to occur in the first simulated pattern, thereby enhancing the effectiveness of optical proximity correction and correspondingly improving the matching degree between the mask pattern formed on the wafer and the target pattern.

[0160] It should be noted that, based on the mask writing rules, the minimum length of the second line segment should not be too small, so that the target pattern after the subsequent second optical proximity correction process is highly mask-writing friendly and can be produced in the mask. To this end, in this embodiment, the minimum length of the second line segment is 20 nm.

[0161] It should also be noted that the length of the second line segment should not be too large or too small. If the length of the second line segment is too large, the length of the remaining first line segment will be too small. In other words, the length of the third line segment will be too small, increasing the computational load for the subsequent second optical proximity correction process. Furthermore, a smaller third line segment will easily lead to more fragmented edges of the target pattern, increasing the cost of mask manufacturing. If the length of the second line segment is too small, it will be difficult to write the target pattern. Furthermore, a smaller second line segment will increase the computational load for the subsequent second optical proximity correction process. Furthermore, a smaller second line segment will easily lead to more fragmented edges of the target pattern, increasing the cost of mask manufacturing. Therefore, in this embodiment, the length of the second line segment is 20 nm to 40 nm.

[0162] In this embodiment, among the adjacent first line segments on both sides of the second sampling point, the first line segments of equal length between the adjacent first sampling points are respectively intercepted and translated to the target position to form the second line segment. The second sampling point is located at the center of the second line segment, which is intuitive, easy to detect, and simple to operate.

[0163] The target position is a middle position of the adjacent first line segments in a second direction, and the second direction is perpendicular to the first direction, that is, the second direction is perpendicular to the extending direction of the first line segments.

[0164] The second line segment is formed at a middle position adjacent to the first line segment in the second direction, which is conducive to obtaining a second initial corrected pattern with better pattern uniformity.

[0165] The second optical proximity correction unit 506 is configured to perform a second optical proximity correction process on the second initially corrected pattern using the plurality of second line segments and third line segments until the absolute values of the edge placement errors at the first sampling points and the second sampling points are within a second threshold range, thereby forming a mask pattern.

[0166] In this embodiment, a model-based optical proximity correction process is used to perform a second optical proximity correction process on the second initially corrected pattern. In other embodiments, an empirical rule-based optical proximity correction process, or a hybrid of a model-based and empirical rule-based optical proximity correction process, may also be used to perform the second optical proximity correction process. In still other embodiments, other suitable optical proximity correction processing methods may also be used.

[0167] In this embodiment, a mask simulation pattern corresponding to the mask pattern is formed accordingly. It should be noted that, at the first sampling point, when the edge placement error E2 is greater than 0, it indicates that the target simulation pattern is located outside the target pattern; when the edge placement error E2 of the target simulation pattern is less than 0, it indicates that the target simulation pattern is located inside the target pattern; and when the edge placement error E2 of the target simulation pattern is equal to 0, it indicates that the target simulation pattern is located on the target pattern. The same applies to the second sampling point. The edge placement errors E2 and E3 at the first and second sampling points can be positive or negative, as long as the absolute values of E2 and E3 are both within the second threshold range.

[0168] It should be noted that the second threshold range should not be too large or too small. If the second threshold range is too large, even when the absolute values of the edge placement errors E2 and E3 at the first and second sampling points are both within the second threshold range, the difference between the target simulated pattern and the target pattern's outline remains significant, making it difficult to achieve the correction effect of the second optical proximity correction process. If the second threshold range is too small, the correction accuracy of the second optical proximity correction process is unnecessarily increased, significantly increasing the computational complexity of the second optical proximity correction process and making correction difficult. To this end, in this embodiment, in the step of performing the second optical proximity correction process on the second initially corrected pattern using multiple second line segments and third line segments, the second threshold range is 0.1 nm to 0.5 nm.

[0169] Specifically, the step of performing a second optical proximity correction process on the second initially corrected pattern using a plurality of second line segments and third line segments includes: performing one or more second correction operations until the absolute values of the edge placement errors E2 and E3 are both within the second threshold range.

[0170] The second correction operation cycle is iterated multiple times until the edge placement errors E2 and E3 at the first sampling point and the second sampling point converge, that is, the absolute values of the edge placement errors E2 and E3 are both within the second threshold range.

[0171] The second correction operation includes: performing simulated exposure on the second initial corrected pattern to obtain a second simulated pattern.

[0172] The second simulated pattern is used to compare with the second initial corrected pattern to obtain an edge placement error corresponding to the simulated exposure pattern.

[0173] The edge placement errors E2 and E3 of the second simulation pattern 320 at the positions of the first sampling point and the second sampling point are calculated.

[0174] Correspondingly, at the position of the first sampling point, when the edge placement error E2 of the second simulated figure is greater than 0, it indicates that the second simulated figure 320 is located outside the target figure; when the edge placement error E2 of the second simulated figure 320 is less than 0, it indicates that the second simulated figure is located inside the target figure; when the edge placement error E2 of the second simulated figure is equal to 0, it indicates that the second simulated figure is located on the target figure. The same applies at the position of the second sampling point.

[0175] The positions of the second line segment and the third line segment are adjusted according to the edge placement errors E2 and E3.

[0176] Specifically, along the second direction, when the edge placement error E2 is greater than 0, the step of adjusting the position of the second line segment includes: moving the corresponding second line segment into the target figure; when the edge placement error E2 is less than 0, the step of adjusting the position of the second line segment includes: moving the corresponding second line segment outside the target figure; when the edge placement error E2 is equal to 0, the step of adjusting the position of the second line segment includes: maintaining the position of the corresponding second line segment, that is, not moving the second line segment. Correspondingly, the same applies to the edge placement error E3 and the corresponding third line segment.

[0177] It should be noted that after performing a second correction operation, in the next second correction operation in the iterative loop, the second initial corrected pattern, obtained by shifting the second and third line segments in the previous second correction operation, is used as the second initial corrected pattern for simulated exposure. In other words, the target pattern obtained by adjusting the position of the first line segment is used as the target pattern for simulated exposure in the next first correction operation.

[0178] Among them, when the absolute values of the edge placement errors E2 and E3 of the second simulation pattern are both within the second threshold range, the second initial corrected pattern after adjusting the positions of the second line segment and the third line segment is used as the mask pattern, and the second simulation pattern is used as the mask simulation pattern.

[0179] In this embodiment, the optical proximity correction is performed twice, thereby improving the accuracy of the optical proximity correction, and the modification to the traditional optical proximity correction is relatively small, and the compatibility is relatively high.

[0180] Correspondingly, the present invention further provides a mask, comprising: a pattern obtained by using the optical proximity correction method provided by an embodiment of the present invention.

[0181] As can be seen from the aforementioned embodiments, compared to a scheme that uses only a plurality of first line segments to perform optical proximity correction on the target pattern, in this embodiment, the plurality of second and third line segments are used to perform the second optical proximity correction on the first initially corrected pattern. This further refines the edges that can be used to perform the second optical correction on the first corrected pattern, thereby improving the accuracy of the second optical correction. Furthermore, compared to a scheme that uses only first sampling points, this embodiment of the present invention provides a greater number of first and second sampling points, which are denser, so that the absolute values of the edge placement errors at the first and second sampling points are both within a second threshold range. This helps reduce the edge placement error of the overall pattern and improves the overall dimensional uniformity of the pattern. For example, it can alleviate the problem of ripple-shaped defects that are prone to occur in the first simulated pattern, thereby enhancing the effectiveness of optical proximity correction. Accordingly, after a mask pattern is formed on a wafer using a reticle, the matching degree between the mask pattern formed on the wafer and the target pattern is improved.

[0182] The embodiment of the present invention further provides a device that can implement the optical proximity correction method provided by the embodiment of the present invention by loading the above optical proximity correction method in the form of a program. An optional hardware structure of the terminal device provided by the embodiment of the present invention can be as follows Figure 19 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.

[0183] 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 via the communication bus 04. The communication interface 02 can be an interface of a communication module for network communication, such as an interface of a GSM module. The processor 01 can be a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention. The memory 03 can include a high-speed RAM memory, or can also include a non-volatile memory (NVM), such as at least one disk storage. The memory 03 stores one or more computer instructions, which are executed by the processor 01 to implement the optical proximity correction method provided in the embodiments of the present invention.

[0184] It should be noted that the above-mentioned terminal device may also include other devices (not shown) that may not be necessary for understanding the contents disclosed in the embodiments of the present invention; given that these other devices may not be necessary for understanding the contents disclosed in the embodiments of the present invention, the embodiments of the present invention will not introduce them one by one.

[0185] An embodiment of the present invention further provides a storage medium storing one or more computer instructions, wherein the one or more computer instructions are used to implement the optical proximity correction method provided by the embodiment of the present invention.

[0186] The embodiments of the present invention can be implemented by various means such as hardware, firmware, software or a combination thereof. In a hardware configuration, the method according to the 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, the embodiments of the present invention can be implemented in the form of modules, processes, functions, etc. The software code can be stored in a memory unit and executed by a processor. The memory unit is located inside or outside the processor and can send data to the processor and receive data from the processor via various known means.

[0187] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. An optical proximity correction method, characterized in that: include: Provide target graphics; Dividing the edge corresponding to the outline of the target graphic into a plurality of sequentially connected first line segments, wherein the first line segment includes two endpoints and a first sampling point located between the two endpoints; Performing a first optical proximity correction process on the target pattern using the plurality of first line segments until the absolute value of the edge placement error at the first sampling point is within a first threshold range, thereby forming a first initial corrected pattern and a first simulated pattern corresponding to the first initial corrected pattern; Determining whether an edge placement error of the first simulation graphic at each endpoint position meets a correction standard; When the edge placement error of the first simulation pattern at the endpoint position reaches a correction standard, the first initial corrected pattern is used as a mask pattern; When the edge placement error of the first simulated figure at the endpoint position does not meet the correction standard, a second sampling point is set at the endpoint position, and among the adjacent first line segments on both sides of the second sampling point, a portion of the first line segment between the adjacent first sampling points is intercepted and translated to a target position to form a second line segment, the second sampling point is located on the second line segment, and the remaining first line segments serve as third line segments. The third line segments are alternately arranged with the second line segments to form a second initial corrected figure; The second initial corrected pattern is subjected to a second optical proximity correction process using the plurality of second line segments and third line segments until the absolute values of the edge placement errors at the first sampling point and the second sampling point are both within a second threshold range, thereby forming a mask pattern.

2. The optical proximity correction method according to claim 1, wherein: In the step of providing the target pattern, the extension direction of the target pattern is a first direction, and the outline of the target pattern has an edge extending along the first direction; In the step of dividing the side corresponding to the outline of the target figure into a plurality of first line segments, the side of the target figure extending along the first direction is divided into a plurality of first line segments.

3. The optical proximity correction method according to claim 1, wherein: The step of determining whether the edge placement error of the first simulated figure at each endpoint position meets the correction standard includes: determining whether the edge placement error of the first simulated figure at each endpoint position meets a first preset condition, the first preset condition being δ1×δ2<0, where δ1 is the edge placement error of the first simulated figure at any endpoint of the first line segment, and δ2 is the edge placement error of the first simulated figure at the other endpoint of the first line segment; When the edge placement error of the first simulation figure at each of the endpoint positions does not meet the first preset condition, the edge placement error of the first simulation figure reaches the correction standard; When the edge placement error of the first simulation pattern at each of the endpoint positions satisfies the first preset condition, determining whether the edge placement error of the first simulation pattern at each of the endpoint positions satisfies a second preset condition, wherein the second preset condition is |δ1-δ2|> a preset value, and the preset value is 5 nm to 10 nm; When the edge placement error of the first simulation figure at each of the endpoint positions does not meet the second preset condition, the edge placement error of the first simulation figure reaches the correction standard; When the edge placement error of the first simulation figure at each of the endpoint positions meets the second preset condition, the edge placement error of the first simulation figure does not meet the correction standard.

4. The optical proximity correction method according to claim 1, wherein: In the step of dividing the edge corresponding to the outline of the target graphic into a plurality of first line segments, the first sampling point is located at the center position of the corresponding first line segment.

5. The optical proximity correction method according to claim 1, wherein: Among the adjacent first line segments on both sides of the second sampling point, the first line segments of equal length between adjacent first sampling points are respectively intercepted and translated to the target position to form a second line segment, and the second sampling point is located at the center position of the second line segment.

6. The optical proximity correction method according to claim 1, wherein: In the step of dividing the edge corresponding to the outline of the target graphic into a plurality of first line segments, the extending direction of the first line segments is a first direction; The target position is a middle position of adjacent first line segments in a second direction, and the second direction is perpendicular to the first direction.

7. The optical proximity correction method according to claim 1, wherein: The step of performing a first optical proximity correction process on the target pattern using the plurality of first line segments includes: performing one or more first correction operations until the absolute value of the edge placement error is within the first threshold range, the first correction operation including: performing simulated exposure on the target pattern to obtain an initial simulated pattern; Calculating an edge placement error of the initial simulation graphic at the position of the first sampling point; adjusting a position of the first line segment according to the edge placement error; When the absolute value of the edge placement error of the initial simulation figure is within the first threshold range, the target figure after adjusting the position of the first line segment is used as the first initial corrected figure, and the initial simulation figure is used as the first simulation figure.

8. The optical proximity correction method according to claim 1, wherein: The step of performing a second optical proximity correction process on the second initial corrected pattern using the plurality of second line segments and third line segments includes: performing one or more second correction operations until the absolute value of the edge placement error is within a second threshold range, the second correction operation including: performing simulated exposure on the second initial corrected pattern to obtain a second simulated pattern; calculating an edge placement error of the second simulation figure at positions of the first sampling point and the second sampling point; adjusting positions of the second line segment and the third line segment according to the edge placement error; When the absolute value of the edge placement error of the second simulation pattern is within the second threshold range, the second initial corrected pattern after adjusting the positions of the second line segment and the third line segment is used as the mask pattern, and the second simulation pattern is used as the mask simulation pattern.

9. The optical proximity correction method according to claim 1, wherein: In the step of performing a first optical proximity correction process on the target pattern using the plurality of first line segments, the first threshold value ranges from 0.1 nm to 0.5 nm.

10. The optical proximity correction method according to claim 1, wherein: In the step of performing a second optical proximity correction process on the second initially corrected pattern using the plurality of second line segments and third line segments, the second threshold value ranges from 0.1 nm to 0.5 nm.

11. The optical proximity correction method according to claim 1, wherein: The length of the first line segment is 40 nm to 200 nm.

12. The optical proximity correction method according to claim 1, wherein: The minimum length of the second line segment is 20 nm.

13. The optical proximity correction method according to claim 12, wherein: The length of the second line segment is 20 nm to 40 nm.

14. The optical proximity correction method according to claim 1, wherein: The optical proximity correction method further includes: after forming the mask pattern, adding an auxiliary pattern around the mask pattern.

15. The optical proximity correction method according to claim 14, wherein: In the step of adding auxiliary patterns around the mask pattern, the auxiliary patterns are scattering strips, and the line width of the auxiliary patterns is greater than or equal to the minimum line width of the mask writing rule and less than or equal to the resolution of the photolithography process.

16. An optical proximity correction system, characterized in that: include: A providing unit, configured to provide a target graphic; A first segmentation unit is configured to segment an edge corresponding to the outline of the target graphic into a plurality of sequentially connected first line segments, wherein the first line segment includes two endpoints and a first sampling point located between the two endpoints; a first optical proximity correction unit, configured to perform a first optical proximity correction process on the target pattern using the plurality of first line segments until an absolute value of an edge placement error at the first sampling point falls within a first threshold range, thereby forming a first initial corrected pattern and a first simulated pattern corresponding to the first initial corrected pattern; a judging unit, configured to judge whether an edge placement error of the first simulation pattern at each endpoint position meets a correction standard, and use the first initial corrected pattern as a mask pattern when the edge placement error of the first simulation pattern at the endpoint position meets the correction standard; a second segmentation unit configured to, when an edge placement error of the first simulated figure at the endpoint position does not meet a correction standard, establish a second sampling point at the endpoint position, and, from adjacent first line segments on both sides of the second sampling point, intercept a portion of the first line segment between adjacent first sampling points and translate the portion to a target position to form a second line segment, wherein the second sampling point is located on the second line segment, and the remaining first line segments serve as third line segments, and the third line segments are alternately arranged with the second line segments to form a second initial corrected figure; The second optical proximity correction unit is configured to perform a second optical proximity correction process on the second initially corrected pattern using the plurality of second line segments and third line segments until the absolute values of the edge placement errors at the first sampling points and the second sampling points are within a second threshold range, thereby forming a mask pattern.

17. A mask, characterized in that: include: A pattern obtained using the optical proximity correction method according to any one of claims 1 to 15.

18. A device, characterized in that The method comprises at least one memory and at least one processor, wherein the memory stores one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the optical proximity correction method according to any one of claims 1 to 15.

19. A storage medium, characterized in that The storage medium stores one or more computer instructions, and the one or more computer instructions are used to implement the optical proximity correction method according to any one of claims 1 to 15.

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