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

Abstract

An optical proximity correction method and system, a mask, a device and a storage medium, the method comprising: adjusting an evaluation point of an ideal contour located at a defect to obtain an adjusted evaluation point; the adjusting comprises: adjusting the position of an original evaluation point of the ideal contour located at the defect along the normal direction of the ideal contour, and being suitable for increasing the absolute value of the edge placement error between the simulation contour corresponding to the corrected pattern and the ideal contour; performing one or more cycle iterations of repair processing on the corrected pattern, each repair processing comprising: taking the adjusted evaluation point as the evaluation point of the ideal contour, and performing global adjustment processing on the corrected pattern based on the difference between the simulation contour corresponding to the corrected pattern and the ideal contour; and determining whether the difference between the simulation contour corresponding to the corrected pattern and the ideal contour is within a preset range. The embodiments of the present application improve the flexibility of the repair processing of the defect, and are beneficial to repairing the defect in a limited number of iterations.

Description

Technical Field

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

[0002] To transfer a pattern from a photomask to the surface of a silicon wafer, it typically involves an exposure step, a development step following the exposure step, and an etching step following the development step.

[0003] However, as device dimensions shrink, the difference between the pattern on the chip surface and the original photomask pattern increases after photolithography. To avoid inconsistencies between the pattern on the chip and the photomask pattern caused by optical proximity effect, the current solution is usually to perform optical proximity correction (OPC) on the photomask pattern, and then perform pattern transfer based on the corrected photomask pattern.

[0004] If there are some defects in the current optical proximity correction pattern, a repair process is required after optical proximity correction.

[0005] However, the current method for repairing images after optical proximity correction is not very effective. Summary of the Invention

[0006] The problem solved by the embodiments of the present invention is to provide an optical proximity correction method and system, mask, device and storage medium, which improves the flexibility of defect repair processing and is beneficial to repairing defects in a limited number of iterations.

[0007] To address the aforementioned problems, embodiments of the present invention provide an optical proximity correction method, comprising: providing a corrected image after optical proximity correction processing; detecting whether the corrected image has defects; when defects are detected in the corrected image, adjusting the evaluation point of the ideal contour located at the defect to obtain an adjusted evaluation point; the adjustment processing includes: adjusting the position of the original evaluation point of the ideal contour located at the defect along the normal direction of the ideal contour, suitable for increasing the absolute value of the edge placement error between the simulated contour and the ideal contour corresponding to the corrected image; after the adjustment processing, performing one or more iterative repair processing on the corrected image, each repair processing including: using the adjusted evaluation point as the evaluation point of the ideal contour, and performing global adjustment processing on the corrected image based on the difference between the simulated contour and the ideal contour corresponding to the corrected image; determining whether the difference between the simulated contour and the ideal contour corresponding to the corrected image is within a preset range; when the difference between the simulated contour and the ideal contour corresponding to the corrected image is within the preset range, determining that the repair processing is complete, and using the corrected image after repair processing as a mask image.

[0008] Accordingly, embodiments of the present invention also provide an optical proximity correction system, comprising: a corrected image providing unit, used to provide a corrected image after optical proximity correction processing; a defect detection unit, used to detect whether the corrected image has defects; an evaluation point adjustment unit, used to adjust the evaluation point of the ideal contour located at the defect when a defect is detected in the corrected image, to obtain an adjusted evaluation point; the adjustment processing includes: adjusting the position of the original evaluation point of the ideal contour located at the defect along the normal direction of the ideal contour, suitable for increasing the absolute value of the edge placement error between the simulated contour and the ideal contour corresponding to the corrected image; a repair processing unit, used to perform one or more iterative repair processing on the corrected image after the adjustment processing, each repair processing including: using the adjusted evaluation point as the evaluation point of the ideal contour, and performing global adjustment processing on the corrected image based on the difference between the simulated contour and the ideal contour corresponding to the corrected image; determining whether the difference between the simulated contour and the ideal contour corresponding to the corrected image is within a preset range; and a mask image output unit, used to determine that the repair processing is completed when the difference between the simulated contour and the ideal contour corresponding to the corrected image is within a preset range, and outputting the corrected image after repair processing as a mask image.

[0009] Accordingly, embodiments of the present invention also provide a mask, the mask including a mask pattern, the mask pattern being formed by the optical proximity correction method provided in embodiments of the present invention.

[0010] Accordingly, embodiments of the present invention also provide an apparatus including at least one memory and at least one processor, wherein the memory stores one or more computer instructions, and the one or more computer instructions are executed by the processor to implement the optical proximity correction method provided in the embodiments of the present invention.

[0011] Accordingly, embodiments of the present invention also provide a storage medium storing one or more computer instructions, which are used to implement the optical proximity correction method provided in the embodiments of the present invention.

[0012] Compared with the prior art, the technical solution of the embodiments of the present invention has the following advantages:

[0013] The optical proximity correction method provided in this invention adjusts the evaluation point of the ideal contour located at the defect when a defect is detected in the corrected pattern, thereby obtaining an adjusted evaluation point. The adjustment process includes: adjusting the position of the original evaluation point of the ideal contour located at the defect along the normal direction of the ideal contour, which is suitable for increasing the absolute value of the edge placement error between the simulated contour and the ideal contour corresponding to the corrected pattern, thereby increasing the severity of the defect. Correspondingly, in the process of using the adjusted evaluation point as the evaluation point of the ideal contour and performing global adjustment processing on the corrected pattern based on the difference between the simulated contour and the ideal contour corresponding to the corrected pattern, on the one hand, it can improve the priority of adjusting the corrected pattern at the defect, and on the other hand, it can also coordinate the adjustment evaluation point and the corresponding line segments around it, which improves the flexibility of defect repair processing. This is beneficial to repair defects in a limited number of iterations, so that the difference between the simulated contour and the ideal contour corresponding to the corrected pattern after repair processing is within a preset range, thereby making the mask pattern meet the process requirements.

[0014] In the optical proximity correction system provided in this embodiment of the invention, when the evaluation point adjustment unit detects a defect in the corrected pattern, it adjusts the evaluation point of the ideal contour located at the defect to obtain an adjusted evaluation point. The adjustment process includes: adjusting the position of the original evaluation point of the ideal contour located at the defect along the normal direction of the ideal contour, which is suitable for increasing the absolute value of the edge placement error between the simulated contour and the ideal contour corresponding to the corrected pattern, thereby increasing the severity of the defect. Correspondingly, in the process of the repair processing unit using the adjusted evaluation point as the evaluation point of the ideal contour and performing global adjustment processing on the corrected pattern based on the difference between the simulated contour and the ideal contour corresponding to the corrected pattern, on the one hand, it can improve the priority of adjusting the corrected pattern at the defect, and on the other hand, it can also coordinate the adjustment evaluation point and the corresponding line segments around it, which improves the flexibility of defect repair processing. This is beneficial to repair defects in a limited number of iterations, so that the difference between the simulated contour and the ideal contour corresponding to the corrected pattern after repair processing is within a preset range, thereby making the mask pattern meet the process requirements. Attached Figure Description

[0015] Figure 1 This is a flowchart of an optical proximity correction method;

[0016] Figure 2 This is a flowchart of an embodiment of the optical proximity correction method of the present invention;

[0017] Figure 3 yes Figure 2 A flowchart of an embodiment of step S1;

[0018] Figure 4This is a schematic diagram of an embodiment of the target graphic and ideal contour;

[0019] Figure 5 Yes Figure 4 A schematic diagram of the corrected image and simulated contour obtained after optical proximity correction processing of the target image in the image.

[0020] Figure 6 Yes Figure 5 A schematic diagram of an embodiment of adjusting evaluation points on the ideal contour;

[0021] Figure 7 Yes Figure 5 A schematic diagram of an embodiment of the mask pattern obtained after the corrected pattern in the image has been repaired;

[0022] Figure 8 This is a functional block diagram of an embodiment of the optical proximity correction system of the present invention;

[0023] Figure 9 This is a schematic diagram of an embodiment of the photomask provided by the present invention;

[0024] Figure 10 This is a hardware structure diagram of an embodiment of the device provided by the present invention. Detailed Implementation

[0025] As the background technology shows, current methods for restoring images after optical proximity correction are not very effective. This paper analyzes the reasons for the poor performance of such restorations using an optical proximity correction method.

[0026] Figure 1 This is a flowchart of an optical proximity correction method.

[0027] refer to Figure 1 Optical proximity correction methods include:

[0028] Step s1: Provide the corrected graphic 10 after optical proximity correction processing;

[0029] Step s2: Check whether the corrected graphic 10 has defects;

[0030] Step s3: When the corrected graphic 10 has defects, perform one or more iterative repair processes on the corrected graphic 10. The repair processes include:

[0031] Step s31: Select the defects that need to be addressed;

[0032] Step s32: Make local adjustments to the corrected graphic at the defect location;

[0033] Step s33: Perform local optical proximity correction verification on the corrected image to determine whether it still has defects;

[0034] Step s4: When the corrected graphic has no defects, the repair process is considered complete, and the corrected graphic is output.

[0035] In the step of dividing the edges of the corrected graphic into multiple line segments and making local adjustments to the corrected graphic at the defect location, the position of the line segment is moved along the normal direction of the line segment based on the edge placement error between the simulated exposure profile and the ideal profile.

[0036] In the process of local adjustment, usually only the line segment corresponding to the defect location is adjusted. Within a limited number of iterations, it is often difficult to make the corrected graphic meet the requirements after local adjustment, and it is difficult to repair the defects in the corrected graphic. If the result of local adjustment is repeatedly repaired, it will easily increase the running time and lead to inefficiency.

[0037] In particular, for larger graphics, the edge placement error is usually larger and the number of line segments is also larger. In a limited number of iterations, it is difficult to make the corrected graphics after local adjustments meet the requirements by simply moving one or a few line segments along the normal direction.

[0038] To address the technical problem, embodiments of the present invention provide an optical proximity correction method. (Reference) Figure 2 The flowchart of an embodiment of the optical proximity correction method of the present invention is shown.

[0039] like Figure 2 As shown, as an example, the optical proximity correction method includes the following basic steps:

[0040] Step S1: Provide the corrected image after optical proximity correction processing;

[0041] Step S2: Check whether the corrected graphic has defects;

[0042] Step S3: When the detected and corrected graphic has defects, the evaluation point of the ideal contour located at the defect is adjusted to obtain the adjusted evaluation point; the adjustment process includes: along the normal direction of the ideal contour, adjusting the position of the original evaluation point of the ideal contour located at the defect, which is suitable for increasing the absolute value of the edge placement error between the simulation contour and the ideal contour corresponding to the corrected graphic.

[0043] Step S4: After the adjustment process, perform one or more iterative repair processes on the corrected graphic. Each repair process includes: Step S41, using the adjustment evaluation point as the evaluation point of the ideal contour, and performing global adjustment processing on the corrected graphic based on the difference between the simulation contour and the ideal contour corresponding to the corrected graphic; Step S42, determining whether the difference between the simulation contour and the ideal contour corresponding to the corrected graphic is within the preset range.

[0044] Step S5: When the difference between the simulated contour and the ideal contour corresponding to the corrected graphic is within the preset range, the repair process is determined to be complete, and the corrected graphic after the repair process is used as the mask graphic.

[0045] In the optical proximity correction method provided in this invention embodiment, when a defect is detected in the corrected pattern, the evaluation point of the ideal contour located at the defect is adjusted to obtain an adjusted evaluation point. The adjustment process includes: adjusting the position of the original evaluation point of the ideal contour located at the defect along the normal direction of the ideal contour, which is suitable for increasing the absolute value of the edge placement error between the simulated contour and the ideal contour corresponding to the corrected pattern, thereby increasing the severity of the defect. Correspondingly, in the process of using the adjusted evaluation point as the evaluation point of the ideal contour and performing global adjustment processing on the corrected pattern based on the difference between the simulated contour and the ideal contour corresponding to the corrected pattern, on the one hand, it can improve the priority of adjusting the corrected pattern at the defect, and on the other hand, it can also coordinate the adjustment evaluation point and the corresponding line segments around it, which improves the flexibility of defect repair processing. This is beneficial to repair defects in a limited number of iterations, so that the difference between the simulated contour and the ideal contour corresponding to the corrected pattern after repair processing is within a preset range, thereby making the mask pattern meet the process requirements.

[0046] To make the above-mentioned objects, features and advantages of the embodiments of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0047] refer to Figures 2 to 5 Step S1: Provide the corrected graphic 100 after optical proximity correction processing (e.g., ... Figure 5 (As shown).

[0048] The corrected pattern 100 is the pattern obtained after optical proximity correction processing of the target pattern. The target pattern is the pattern that needs to be formed on the wafer. After optical proximity correction processing of the target pattern, the corrected pattern 100 is used to make a photomask, and then the photolithography process is performed using the photomask to form the corresponding pattern on the wafer.

[0049] If the corrected graphic 100 still has defects, it needs to be repaired. The repaired graphic 100 is then used to make a mask.

[0050] refer to Figure 3 , showed Figure 2 A flowchart of an embodiment of step S1. Figure 4 A schematic diagram of an embodiment of the target graphic and its corresponding ideal contour is shown. Figure 5 It shows the Figure 4 The diagram shows the corrected image and simulated contour obtained by optical proximity correction processing on the target image.

[0051] In this embodiment, step S1 of providing the corrected image after optical proximity correction processing includes:

[0052] Reference Figure 3 and Figure 4 Step S11: Provide the target graphic (Target Layer) 110.

[0053] Target pattern 110 is the pattern that needs to be formed on the wafer.

[0054] In the process of optical proximity correction of target graphic 110, in order to reduce the arbitrariness of edge movement, the position of line segments is adjusted (e.g., line segments are translated) to reduce edge placement error, thereby dividing the edge of target graphic 110 into multiple sequentially connected line segments, and then optical proximity correction is performed by translating line segments.

[0055] Therefore, in this embodiment, the edge of the target graphic 110 is composed of multiple line segments extending along the extension direction of the edge.

[0056] Continue to refer to Figure 3 and Figure 4 Step S12: Based on the target graphic 110, obtain the ideal contour 120.

[0057] The ideal profile 120 is used as a reference for optical proximity effect correction and subsequent repair processing.

[0058] Specifically, the corners of the target graphic 110 are usually right angles. The target graphic 110 is simulated to simulate the contour formed after the high-frequency signal is lost at the corner position, which is used as the ideal contour 120.

[0059] Continue to refer to Figure 3 and Figure 5Step S13: Based on the difference between the simulated contour 130 and the ideal contour 120 corresponding to the target graphic 110, optical proximity correction processing is performed on the target graphic 110 to obtain the corrected graphic 100.

[0060] Specifically, in this embodiment, the step of performing optical proximity correction processing on the target graphic 110 based on the difference between the simulated contour and the ideal contour 120 corresponding to the target graphic 110 includes: setting an evaluation point (Merit Point) 130 on the ideal contour 120; calculating the edge placement error value from the simulated contour to the evaluation point 130 on the normal line of the evaluation point 130; calculating the cost function based on the edge placement error value, and iteratively pulling the line segment multiple times to minimize the edge placement error between the simulated contour and the ideal contour 120 in the global range.

[0061] In this embodiment, during the optical proximity correction process, the evaluation point 130 is set on the ideal contour 120 and is used as a reference point for calculating the edge placement error between the simulated contour and the ideal contour 120.

[0062] As an example, the step of setting evaluation points 130 on the ideal contour 120 includes setting evaluation points 130 on the ideal contour 120 based on the line segment type of the target graphic 110.

[0063] The line segment type includes one or more of the following: straight line, concave corner edge, and convex corner edge. For example, for a straight line segment, evaluation points 130 can be distributed and set on the edge corresponding to the ideal contour; for concave corner edges and convex corner edges, evaluation points 130 can be set on the edge corresponding to the ideal contour at a position away from the concave or convex corner.

[0064] In this embodiment, the edge placement error value from the simulated profile to the evaluation point 130 on the normal line of the evaluation point 130 is calculated, which is to say, the distance between the simulated profile and the evaluation point 130 in the normal direction of the evaluation point 130 is calculated.

[0065] The simulated contour is the graphic obtained after performing simulated exposure processing on the corrected graphic 100.

[0066] Specifically, in this embodiment, the cost function is calculated based on formula (I):

[0067]

[0068] Where pw is the exposure process window, merit is the evaluation point, EPE is the edge placement error function, weight is the weight of the edge placement error, and f(MRC) is the mask manufacturability rule constraint function.

[0069] Reference Figure 5 This shows the Figure 4 The diagram shows the corrected image and simulated contour obtained by optical proximity correction processing on the target image. The simulated contour 140 is the contour obtained after simulated exposure processing on the corrected image 100.

[0070] In the photolithography process, a photoresist material is exposed using a photomask to form a pattern on the photoresist material. Therefore, in this embodiment, by making the simulated contour 140 close to the ideal contour 120, it is beneficial to make the difference between the pattern obtained after exposure and development on the photoresist material and the target pattern 110 smaller.

[0071] refer to Figure 2 Step S2: Detect whether the corrected graphic 100 has defects.

[0072] Check whether the corrected graphic 100 has defects so that the defects can be repaired later.

[0073] Specifically, after optical proximity correction processing, optical proximity correction verification (OPCV) processing is performed, and verification results (OPCV result) are output; based on the verification results, defects that need to be processed are selected.

[0074] Among them, the defect types include: edge placement error defects, and defects in the relationship between graphics.

[0075] Specifically, defects in the relationship between graphics refer to defects in the positional relationship between adjacent graphics, such as: the distance between adjacent graphics does not meet the process or design requirements; or there is a bridging between adjacent graphics.

[0076] As an example, in this embodiment, during the optical proximity correction process, the line segment is pulled multiple times to minimize the edge placement error between the simulated contour and the ideal contour 120 in the global range. Therefore, in specific implementation, it is difficult to avoid that the edge placement error is still large in some local areas, which is difficult to meet the process requirements. Thus, the defect of edge placement error not meeting the process requirements is repaired.

[0077] It should be noted that continued reference is necessary. Figure 2 In this embodiment, the optical proximity correction method further includes: after detecting whether the corrected pattern 100 has defects, and before adjusting the evaluation point where the ideal contour is located at the defect, step S6 is executed: obtaining defects with edge placement errors greater than or equal to a preset threshold as priority defects.

[0078] By prioritizing defects, in practical implementation, defects selected based on pre-set conditions can be repaired first, increasing the priority of repairing these priority defects. Furthermore, defects with large edge placement errors are more likely to fail to meet process requirements even after repair. By prioritizing these defects, subsequent repairs can be carried out on a larger scale, significantly improving the effectiveness of the repair process.

[0079] It should be noted that the preset threshold should not be too small or too large. If the preset threshold is too small, it may lead to an increase in the number of defects screened, thereby increasing the computational load and weakening the correction effect on the prioritized defects; if the preset threshold is too large, it may miss defects with large edge placement errors, resulting in ineffective correction. As an example, the preset threshold is 20nm.

[0080] In other embodiments, the preset threshold may be other values ​​based on actual process requirements.

[0081] In this embodiment, the optical proximity correction method further includes:

[0082] refer to Figure 2 Step S7: When the corrected pattern 100 is found to have no defects, the corrected pattern 100 is used as a mask pattern.

[0083] If the corrected pattern 100 has no defects, it means that the corrected pattern 100 meets the process and design requirements. Accordingly, the corrected pattern 100 is used as the mask pattern, and the mask pattern is used to make the mask.

[0084] Continue to refer to Figure 2 Step S3: When the detected and corrected graphic 100 has a defect, the evaluation point of the ideal contour 120 located at the defect is adjusted to obtain the adjusted evaluation point. The adjustment process includes: along the normal direction of the ideal contour 120, adjusting the position of the original evaluation point 130 of the ideal contour 20 located at the defect, which is suitable for increasing the absolute value of the edge placement error between the simulation contour corresponding to the corrected graphic 100 and the ideal contour 120.

[0085] Along the normal direction of the ideal contour 120, the position of the original evaluation point 130 of the ideal contour 20 at the defect is adjusted. This is suitable for increasing the absolute value of the edge placement error between the simulation contour corresponding to the corrected graphic 100 and the ideal contour 120, thereby increasing the severity of the defect. In the subsequent one or more iterative repair processes, this can increase the priority of repairing the corrected graphic at the defect, which is beneficial for repairing the defect in a limited number of iterations.

[0086] In this embodiment, the step of adjusting the evaluation points of the ideal contour 120 located at the defect includes: adjusting the evaluation points of the ideal contour 120 located at the priority defect location, thereby increasing the priority of subsequent repair of the priority defect location.

[0087] In this embodiment, the step of adjusting the position of the original evaluation point 130 of the ideal contour 20 located at the defect along the normal direction of the ideal contour 120 includes: moving the original evaluation point 130 located at the defect along the normal direction of the ideal contour 120 by a preset distance along the direction of increasing the absolute value of the edge placement error between the simulation contour 130 and the ideal contour 120.

[0088] In this embodiment, the adjustment process further includes: obtaining a preset distance before moving the original evaluation point 130 along the normal of the ideal contour 120 by a preset distance in the direction of increasing the absolute value of the edge placement error between the simulation contour 140 and the ideal contour 120.

[0089] In this embodiment, the step of obtaining the preset distance includes: performing one or more iterative simulation processing, the simulation processing including: moving the evaluation point along the direction of the normal of the ideal contour 120 by a test step size in the direction of increasing the absolute value of the edge placement error between the simulation contour 140 and the ideal contour 120; after moving the evaluation point along the direction of the normal of the ideal contour 120 by a test step size, performing simulated optical proximity correction processing on the corrected graphic 100; after performing simulated optical proximity correction processing, detecting the difference between the simulation contour 140 and the ideal contour 120; when the difference between the simulation contour 140 and the ideal contour 120 is the smallest, outputting the corresponding test step size accumulation value as the preset distance.

[0090] The distance between the original evaluation points and the normal direction of the ideal contour 120 should not be too small or too large. If the distance is too small, it may increase the probability that the defect location will not be completely repaired after subsequent repair processing; if the distance is too large, it may lead to over-repair of the defect location in the subsequent process. Therefore, in this embodiment, the distance between the original evaluation points and the normal direction of the ideal contour is 1 nm to 10 nm.

[0091] In this embodiment, the adjustment process further includes setting new evaluation points on the ideal contour 120 located at the defect. These evaluation points are used to calculate edge placement errors. By setting new evaluation points on the ideal contour 120 corresponding to the defect, the number of defects with large edge placement errors is increased, thereby further determining the weight and priority of subsequent repair processing at the defect location.

[0092] In this embodiment, the ideal contour corresponds to the target graphic 110; the step of setting new evaluation points on the ideal contour located at the defect includes: setting new evaluation points on the ideal contour based on the line segment type corresponding to the target graphic 110 at the defect location and the preset interval between evaluation points.

[0093] The line segment types include one or more of the following: straight line, concave side, and convex side.

[0094] In this embodiment, in the step of adjusting the position of the original evaluation point of the ideal contour at the defect along the normal direction of the ideal contour, the position of the newly added evaluation point is also adjusted along the normal direction of the ideal contour. This is suitable for increasing the absolute value of the edge placement error between the simulated contour and the ideal contour corresponding to the corrected graphic 100. Therefore, the absolute value of the edge placement error calculated using the newly added evaluation point is also larger than the actual absolute value of the edge placement error, which is conducive to further increasing the severity of the defect and increasing the priority of subsequent defect repair processing.

[0095] Reference Figure 5 and Figure 6 As an example, the evaluation point of the defect (located at point P, indicated by the dashed circle in the figure) is adjusted. Specifically, as an example, the position of the original evaluation point 130, where the ideal contour is located at the defect, is adjusted along the normal direction of the original evaluation point 130 and in the direction of increasing edge placement error. The adjusted original evaluation point is used as the updated evaluation point 131. Furthermore, a new evaluation point 132 is added at the defect, and its position is adjusted in the direction of increasing edge placement error. Accordingly, the adjusted evaluation points include the updated evaluation point 131 and the new evaluation point 132.

[0096] refer to Figure 2 Step S4: After adjustment, the corrected graphic 100 undergoes one or more iterative repair processes. In this embodiment, by adjusting the evaluation points at the defect location, the severity of the defect is increased, which helps to increase the priority of repairing the corrected graphic 100 at the defect location, and consequently helps to repair the defect within a limited number of iterations.

[0097] As an example, each repair process includes:

[0098] Step S41 is executed, using the adjustment evaluation point as the evaluation point of the ideal contour, and performing global adjustment processing on the corrected graphic based on the difference between the simulation contour and the ideal contour corresponding to the corrected graphic 100.

[0099] Using the adjustment evaluation point as the evaluation point of the ideal contour, the corrected graphic is globally adjusted based on the difference between the simulated contour and the ideal contour. This increases the priority of adjusting the corrected graphic at defects and enables coordinated adjustment of the adjustment evaluation point and its surrounding line segments, improving the flexibility of defect repair. Consequently, it is beneficial to repair defects within a limited number of iterations, ensuring that the difference between the simulated contour and the ideal contour of the corrected graphic is within a preset range, thus enabling the mask graphic to meet the process requirements.

[0100] In this embodiment, the steps of performing global adjustment processing on the corrected graphic 100 include: using the adjustment evaluation point as the evaluation point of the ideal contour 120, updating the edge placement error cost function (EPE cost function); and based on the updated edge placement error cost function, moving the evaluation point and the corresponding line segments around the evaluation point along the direction of the line segment normal.

[0101] In this embodiment, the edge placement error cost function is calculated based on formula (II):

[0102]

[0103] Where merit is the evaluation point, EPE is the edge placement error function, weight is the weight of the edge placement error function, and f(MRC) is the mask manufacturability rule constraint function.

[0104] Execute step S42 to determine whether the difference between the simulated contour and the ideal contour corresponding to the corrected graphic is within the preset range.

[0105] In this embodiment, the step of determining whether the difference between the simulated contour and the ideal contour corresponding to the corrected graphic 100 is within a preset range includes: using the original evaluation point as the evaluation point of the ideal contour, calculating the difference between the simulated contour and the ideal contour corresponding to the corrected graphic; and determining whether the difference is within a preset range.

[0106] Using the original evaluation point as the evaluation point of the ideal contour, the difference between the simulated contour and the ideal contour corresponding to the corrected graphic is calculated, thereby comparing the simulated contour with the actual ideal contour to determine whether the difference between the simulated contour and the ideal contour is within the preset range.

[0107] Specifically, at each original evaluation point location, the distance between the simulation profile and the original evaluation point is calculated along the normal direction of the evaluation point, and this distance is used as the difference.

[0108] refer to Figure 2Step S5: When the difference between the simulation contour corresponding to the corrected graphic 100 and the ideal contour 120 is within a preset range, it is determined that the repair process is complete, and the corrected graphic 100 after the repair process is used as the mask graphic 150.

[0109] The mask pattern 150 is used to create a mask. The corrected pattern 100 after repair processing is used as the mask pattern, thereby improving the matching degree between the exposed pattern formed on the wafer and the target pattern 110 after subsequent exposure using the mask.

[0110] Reference Figure 7 The diagram shows a schematic representation of a mask pattern obtained after repairing a modified pattern.

[0111] like Figure 7 As shown, at the dashed circle P, the difference between the simulated contour 160 and the ideal contour 120 corresponding to the mask pattern 150 is significantly reduced, which improves the effect of repairing the corrected pattern 100.

[0112] Accordingly, the present invention also provides an optical proximity correction system. Figure 8 This is a functional block diagram of an embodiment of the optical proximity correction system of the present invention.

[0113] refer to Figure 8 In this embodiment, the optical proximity correction system 200 includes: a corrected graphic providing unit 21, used to provide a corrected graphic after optical proximity correction processing; a defect detection unit 22, used to detect whether the corrected graphic has defects; and an evaluation point adjustment unit 23, used to adjust the evaluation point of the ideal contour located at the defect when a defect is detected in the corrected graphic, to obtain an adjusted evaluation point; the adjustment process includes: adjusting the position of the original evaluation point of the ideal contour located at the defect along the normal direction of the ideal contour, which is suitable for increasing the absolute value of the edge placement error between the simulated contour and the ideal contour corresponding to the corrected graphic; and repairing the defect. The processing unit 24 is used to perform one or more iterative repair processes on the corrected graphic after adjustment processing. Each repair process includes: using the adjustment evaluation point as the evaluation point of the ideal contour, and performing global adjustment processing on the corrected graphic based on the difference between the simulation contour and the ideal contour corresponding to the corrected graphic; determining whether the difference between the simulation contour and the ideal contour corresponding to the corrected graphic is within a preset range; the mask graphic output unit 25 is used to determine that the repair processing is complete when the difference between the simulation contour and the ideal contour corresponding to the corrected graphic is within a preset range, and output the corrected graphic after repair processing as a mask graphic.

[0114] In the optical proximity correction system 200, when the evaluation point adjustment unit 23 detects a defect in the corrected pattern, it adjusts the evaluation point of the ideal contour located at the defect to obtain an adjusted evaluation point. The adjustment process includes adjusting the position of the original evaluation point of the ideal contour located at the defect along the normal direction of the ideal contour. This is suitable for increasing the absolute value of the edge placement error between the simulated contour and the ideal contour corresponding to the corrected pattern, thereby increasing the severity of the defect. Correspondingly, in the process of the repair processing unit 24 using the adjusted evaluation point as the evaluation point of the ideal contour and performing global adjustment processing on the corrected pattern based on the difference between the simulated contour and the ideal contour corresponding to the corrected pattern, on the one hand, it can improve the priority of adjusting the corrected pattern at the defect, and on the other hand, it can also coordinate the adjustment evaluation point and the corresponding line segments around it, improving the flexibility of defect repair processing. This is beneficial for repairing defects in a limited number of iterations, so that the difference between the simulated contour and the ideal contour corresponding to the corrected pattern after repair processing is within a preset range, thereby making the mask pattern meet the process requirements.

[0115] The corrected graphic providing unit 21 is used to provide a corrected graphic that has undergone optical proximity correction processing.

[0116] The corrected pattern 100 is the pattern obtained after optical proximity correction processing of the target pattern. The target pattern is the pattern that needs to be formed on the wafer. After optical proximity correction processing of the target pattern, the corrected pattern 100 is used to make a photomask, and then the photolithography process is performed using the photomask to form the corresponding pattern on the wafer.

[0117] If the corrected graphic 100 still has defects, it needs to be repaired. The repaired graphic 100 is then used to make a mask.

[0118] Reference Figure 4 In this embodiment, the corrected graphic providing unit 21 includes: a target graphic provider (not shown) for providing a target graphic (Target Layer) 110; an ideal contour acquirer (not shown) for obtaining an ideal contour (Ideal Contour) 120 based on the target graphic 110; and a corrector (not shown) for performing optical proximity correction processing on the target graphic 110 based on the difference between the simulated contour (Simulate Contour) 130 and the ideal contour 120 corresponding to the target graphic 110, to obtain the corrected graphic 100.

[0119] Target pattern 110 is the pattern that needs to be formed on the wafer.

[0120] In the process of optical proximity correction processing of target graphic 110, in order to reduce the arbitrariness of edge movement, the position of line segments is adjusted (e.g., line segments are translated) to reduce edge placement error, thereby dividing the edge of target graphic 110 into multiple sequentially connected line segments, and then optical proximity correction processing is performed by translating line segments.

[0121] Therefore, in this embodiment, the edge of the target graphic 110 is composed of multiple line segments extending along the extension direction of the edge.

[0122] The ideal contour acquirer is used to obtain an ideal contour 120 based on the target graphic 110. The ideal contour 120 is used as a reference for optical proximity effect correction processing and repair processing.

[0123] Specifically, the corners of the target graphic 110 are usually right angles. The ideal contour acquirer is used to simulate the target graphic 110 and simulate the contour formed after the high-frequency signal is lost at the corner position of the target graphic 110, which is used as the ideal contour 120.

[0124] The corrector is used to perform optical proximity correction processing on the target graphic 110 based on the difference between the simulated contour and the ideal contour 120 corresponding to the target graphic 110.

[0125] Specifically, the corrector is used to set an evaluation point 130 on the ideal profile 120, calculate the edge placement error value between the simulated profile and the evaluation point 130 on the normal of the evaluation point 130, calculate the cost function based on the edge placement error value, and iteratively pull the line segment to minimize the edge placement error between the simulated profile and the ideal profile 120 in the global range.

[0126] The evaluation point 130 is set on the ideal contour 120 and is used as a reference point for calculating the edge placement error between the simulated contour and the ideal contour 120.

[0127] As an example, based on the line segment type of the target graphic 110, evaluation points 130 are set on the ideal contour.

[0128] The line segment type includes one or more of the following: straight line, concave corner edge, and convex corner edge. For example, for a straight line segment, evaluation points 130 can be distributed and set on the edge corresponding to the ideal contour 120; for concave corner edges and convex corner edges, evaluation points 130 can be set on the edge corresponding to the ideal contour 120 at a position away from the concave or convex corner.

[0129] In this embodiment, the edge placement error value from the simulated profile to the evaluation point 130 on the normal line of the evaluation point 130 is calculated, which is to say, the distance between the simulated profile and the evaluation point 130 in the normal direction of the evaluation point 130 is calculated.

[0130] The simulated contour is the image obtained after simulating exposure processing on the corrected image.

[0131] Specifically, in this embodiment, the cost function is calculated based on formula (I):

[0132]

[0133] Where pw is the exposure process window, merit is the evaluation point, EPE is the edge placement error function, weight is the weight of the edge placement error, and f(MRC) is the mask manufacturability rule constraint function.

[0134] Reference Figure 5 This shows the Figure 4 The diagram shows the corrected image and simulated contour obtained by optical proximity correction processing on the target image. The simulated contour 140 is the contour obtained after simulated exposure processing on the corrected image 100.

[0135] In the photolithography process, a photoresist material is exposed using a photomask to form a pattern on the photoresist material. Therefore, in this embodiment, by making the simulated contour 140 close to the ideal contour 120, it is beneficial to make the difference between the pattern obtained after exposure and development on the photoresist material and the target pattern smaller.

[0136] The defect detection unit 22 is used to detect whether the corrected graphic 100 has defects, so that the repair processing unit 24 can repair the defects.

[0137] Specifically, after optical proximity correction processing, optical proximity correction verification (OPCV) processing is performed, and verification results (OPCV result) are output; based on the verification results, defects that need to be processed are selected.

[0138] For example, defect types include: edge placement error defects and defects in the relationship between graphics.

[0139] Specifically, defects in the relationship between graphics refer to defects in the positional relationship between adjacent graphics, such as: the distance between adjacent graphics does not meet the process or design requirements; or there is a bridging between adjacent graphics.

[0140] As an example, in this embodiment, the corrector iterates and pulls the line segment multiple times during the optical proximity correction process to minimize the edge placement error between the simulated contour and the ideal contour 120 in the global range. Therefore, in specific implementations, it is difficult to avoid the edge placement error still being large in some local areas, which is difficult to meet the process requirements. Consequently, it is necessary to repair the defect that the edge placement error does not meet the process requirements.

[0141] It should be noted that, in this embodiment, the optical proximity correction system 200 further includes: a defect screening unit 26, used to acquire defects whose edge placement error is greater than or equal to a preset threshold, as priority defects to be processed, and output the priority defects to the evaluation point adjustment unit 23.

[0142] The defect screening unit 26 selects priority defects for processing. In practice, the repair processing unit 25 can prioritize the repair of these selected defects based on pre-set conditions, thus increasing the priority of repairing them. Furthermore, defects with large edge placement errors are more likely to fail to meet process requirements even after repair. By prioritizing these defects, the repair processing unit 25 can significantly improve the repair efficiency.

[0143] It should be noted that the preset threshold should not be too small or too large. If the preset threshold is too small, it may lead to an increase in the number of defects screened, thereby increasing the computational load and weakening the correction effect on the prioritized defects; if the preset threshold is too large, it may miss defects with large edge placement errors, resulting in ineffective correction. As an example, the preset threshold is 20nm.

[0144] It should be noted that in this embodiment, when the defect detection unit 22 detects that the corrected graphic 100 does not have defects, the corrected graphic 100 is output to the mask graphic output unit 25 as a mask graphic.

[0145] If the corrected pattern 100 has no defects, it means that the corrected pattern 100 meets the process and design requirements. Accordingly, the corrected pattern 100 is used as the mask pattern, and the mask pattern is used to make the mask.

[0146] The evaluation point adjustment unit 23 adjusts the position of the original evaluation point 130 of the ideal contour 20 at the defect along the normal direction of the ideal contour 120. This is suitable for increasing the absolute value of the edge placement error between the simulation contour and the ideal contour 120 corresponding to the corrected graphic 100, thereby increasing the severity of the defect. During the repair processing unit 24's one or more iterative repair processes, it can increase the priority of repairing the corrected graphic 100 at the defect, which is beneficial for repairing the defect within a limited number of iterations.

[0147] In this embodiment, the evaluation point adjustment unit 23 adjusts the evaluation points of the ideal contour 120 located at the priority defect location, thereby increasing the priority of the repair processing unit 24 in repairing the priority defect location.

[0148] Specifically, in this embodiment, the evaluation point adjustment unit 23 moves the original evaluation point 130 located at the defect along the normal direction of the ideal contour 120 in the direction of increasing the absolute value of the edge placement error between the simulation contour 130 and the ideal contour 120.

[0149] Accordingly, in this embodiment, the evaluation point adjustment unit 23 is also used to obtain a preset distance before moving the original evaluation point 130 along the normal of the ideal contour 120 by a preset distance in the direction of increasing the absolute value of the edge placement error between the simulation contour 140 and the ideal contour 120.

[0150] In this embodiment, the evaluation point adjustment unit 23 performs one or more iterative simulation processes to obtain a preset distance. The simulation process includes: moving the evaluation point along the direction of the normal of the ideal contour 120 by a test step size in the direction of increasing the absolute value of the edge placement error between the simulated contour 140 and the ideal contour 120; after moving the evaluation point along the direction of the normal of the ideal contour 120 by a test step size, performing simulated optical proximity correction processing on the corrected graphic 100; after performing simulated optical proximity correction processing, detecting the difference between the simulated contour 140 and the ideal contour 120; and when the difference between the simulated contour 140 and the ideal contour 120 is the smallest, outputting the corresponding accumulated test step size value as the preset distance.

[0151] The distance between the original evaluation points and the normal direction of the ideal contour 120 should not be too small or too large. If the distance is too small, it may increase the probability that the defect location will not be completely repaired after the repair process; if the distance is too large, it may lead to over-repair at the defect location, resulting in the difference between the simulated contour and the ideal contour at the defect location still failing to meet the process requirements. Therefore, in this embodiment, the distance between the original evaluation points and the normal direction of the ideal contour is adjusted to 1 nm to 10 nm.

[0152] In this embodiment, the evaluation point adjustment unit 23 is also used to set new evaluation points on the ideal profile 120 located at the defect.

[0153] Evaluation points are used to calculate edge placement error. By setting new evaluation points on the ideal contour 120 corresponding to the defect, the number of defects with large edge placement errors is increased, thereby further determining the weight and priority of subsequent repair processing of the defects.

[0154] In this embodiment, the ideal contour corresponds to the target graphic; the step of setting new evaluation points on the ideal contour located at the defect includes: setting new evaluation points on the ideal contour based on the line segment type corresponding to the target graphic 110 at the defect location and the preset interval between evaluation points.

[0155] The line segment types include one or more of the following: straight line, concave side, and convex side.

[0156] In this embodiment, the evaluation point adjustment unit 23 is also used to adjust the position of the newly added evaluation points along the normal direction of the ideal contour, which is suitable for increasing the absolute value of the edge placement error between the simulated contour and the ideal contour corresponding to the corrected graphic. Therefore, the absolute value of the edge placement error calculated using the newly added evaluation points is also larger than the actual absolute value of the edge placement error, which is conducive to further increasing the severity of the defect and increasing the priority of subsequent defect repair processing.

[0157] Reference Figure 5 and Figure 6 As an example, the evaluation point of the defect (located at point P, indicated by the dashed circle in the figure) is adjusted. Specifically, as an example, the position of the original evaluation point 130, where the ideal contour is located at the defect, is adjusted along the normal direction of the original evaluation point 130 and in the direction of increasing edge placement error. The adjusted original evaluation point is used as the updated evaluation point 131. Furthermore, a new evaluation point 132 is added at the defect, and its position is adjusted in the direction of increasing edge placement error. Accordingly, the adjusted evaluation points include the updated evaluation point 131 and the new evaluation point 132.

[0158] In this embodiment, the evaluation point adjustment unit 23 adjusts the evaluation points at the defect, thereby increasing the severity of the defect. Correspondingly, this increases the priority of the repair processing unit 24 in repairing the corrected graphic at the defect, which in turn helps to repair the defect within a limited number of iterations.

[0159] As an example, each repair process includes: using the adjustment evaluation point as the evaluation point of the ideal contour, performing a global adjustment on the corrected graphic based on the difference between the simulated contour and the ideal contour corresponding to the corrected graphic; and determining whether the difference between the simulated contour and the ideal contour corresponding to the corrected graphic is within a preset range.

[0160] Using the adjustment evaluation point as the evaluation point of the ideal contour, the corrected graphic is globally adjusted based on the difference between the simulated contour and the ideal contour. This increases the priority of adjusting the corrected graphic at defects and enables coordinated adjustment of the adjustment evaluation point and its surrounding line segments, improving the flexibility of defect repair. Consequently, it is beneficial to repair defects within a limited number of iterations, ensuring that the difference between the simulated contour and the ideal contour of the corrected graphic is within a preset range, thus enabling the mask graphic to meet the process requirements.

[0161] In this embodiment, the global adjustment processing of the corrected graphic 100 by the repair processing unit 24 includes: using the adjustment evaluation point as the evaluation point of the ideal contour 120, updating the edge placement error cost function (EPE cost function); and based on the updated edge placement error cost function, moving the evaluation point and the corresponding line segments around the evaluation point along the direction of the line segment normal.

[0162] In this embodiment, the edge placement error cost function is calculated based on formula (II):

[0163]

[0164] Where merit is the evaluation point, EPE is the edge placement error function, weight is the weight of the edge placement error function, and f(MRC) is the mask manufacturability rule constraint function.

[0165] In this embodiment, determining whether the difference between the simulated contour and the ideal contour corresponding to the corrected graphic is within a preset range includes: using the original evaluation point as the evaluation point of the ideal contour, calculating the difference between the simulated contour and the ideal contour corresponding to the corrected graphic; and determining whether the difference is within a preset range.

[0166] Using the original evaluation point as the evaluation point of the ideal contour, the difference between the simulated contour and the ideal contour corresponding to the corrected graphic is calculated, thereby comparing the simulated contour with the actual ideal contour to determine whether the difference between the simulated contour and the ideal contour is within the preset range.

[0167] Specifically, at each original evaluation point location, the distance between the simulation profile and the original evaluation point is calculated along the normal direction of the evaluation point, and this distance is used as the difference.

[0168] The mask pattern output unit 25 is used to determine that the repair process is complete when the difference between the simulated contour corresponding to the corrected pattern 100 and the ideal contour 120 is within a preset range, and to use the corrected pattern 100 after repair process as the mask pattern 150.

[0169] The mask pattern 150 is used to create a mask, using the repaired and corrected pattern 100 as the mask pattern, thereby improving the matching degree between the exposed pattern formed on the wafer and the target pattern after subsequent exposure using the mask.

[0170] like Figure 7 As shown, at the dashed circle P, the difference between the simulated contour 160 and the ideal contour 120 corresponding to the mask pattern 150 is significantly reduced, which improves the effect of repairing the corrected pattern 100.

[0171] Accordingly, the present invention also provides a photomask. Figure 9 This is a schematic diagram of an embodiment of the photomask provided in this invention.

[0172] In this embodiment, the mask 300 includes a mask pattern 30, which is formed by the optical proximity correction method described in the previous embodiment.

[0173] As can be seen from the foregoing description, the optical proximity correction method of the aforementioned embodiment is beneficial for repairing defects in a limited number of iterations, so that the difference between the simulated contour and the ideal contour corresponding to the corrected pattern after repair is within a preset range, thereby enabling the mask pattern to meet the process requirements. Accordingly, after exposure using the mask with the mask pattern 150, it is beneficial to improve the matching degree between the exposed pattern and the target pattern formed on the wafer.

[0174] This invention also provides a device that can implement the optical proximity correction method provided in this invention by loading a program.

[0175] An optional hardware structure for the terminal device provided in this embodiment of the invention can be as follows: Figure 10 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.

[0176] In this embodiment, the number of processor 01, communication interface 02, memory 03 and communication bus 04 is at least one, and processor 01, communication interface 02 and memory 03 communicate with each other through communication bus 04.

[0177] Communication interface 02 can be an interface for a communication module used for network communication, such as the interface of a GSM module. Processor 01 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. Memory 03 may include high-speed RAM memory and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0178] 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 this embodiment of the invention.

[0179] It should be noted that the aforementioned terminal device may also include other devices (not shown) that may not be essential to understanding the content disclosed in the embodiments of the present invention; given that these other devices may not be essential for understanding the content disclosed in the embodiments of the present invention, the embodiments of the present invention will not describe them one by one.

[0180] This invention also provides a storage medium storing one or more computer instructions for implementing the optical proximity correction method provided in this invention.

[0181] Embodiments of the present invention can be implemented by various means, such as hardware, firmware, software, or combinations thereof. In a hardware configuration, the method according to an exemplary embodiment of the present invention can be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, etc.

[0182] In firmware or software configuration, embodiments of the present invention can be implemented in the form of modules, processes, functions, etc. Software code can be stored in a memory unit and executed by a processor. The memory unit is located inside or outside the processor and can send data to and receive data from the processor via various known means.

[0183] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An optical proximity correction method, characterized in that, include: Provides corrected graphics after optical proximity correction; Check whether the corrected graphic has defects; When a defect is detected in the corrected graphic, the evaluation point of the ideal contour located at the defect is adjusted to obtain an adjusted evaluation point. The adjustment process includes: adjusting the position of the original evaluation point of the ideal contour located at the defect along the normal direction of the ideal contour, which is suitable for increasing the absolute value of the edge placement error between the simulation contour and the ideal contour corresponding to the corrected graphic. After the adjustment process, the corrected graphic is subjected to one or more iterative repair processes. Each repair process includes: using the adjustment evaluation point as the evaluation point of the ideal contour, and performing a global adjustment process on the corrected graphic based on the difference between the simulated contour and the ideal contour corresponding to the corrected graphic; and determining whether the difference between the simulated contour and the ideal contour corresponding to the corrected graphic is within a preset range. When the difference between the simulated contour and the ideal contour corresponding to the corrected graphic is within a preset range, the repair process is considered complete, and the corrected graphic after the repair process is used as the mask graphic.

2. The optical proximity correction method as described in claim 1, characterized in that, The adjustment process also includes setting new evaluation points on the ideal profile located at the defect.

3. The optical proximity correction method as described in claim 2, characterized in that, The ideal contour corresponds to the target graphic; The step of setting new evaluation points on the ideal contour located at the defect includes: setting new evaluation points on the ideal contour based on the line segment type corresponding to the defect location of the target graphic and the preset interval between evaluation points.

4. The optical proximity correction method as described in claim 3, characterized in that, The line segment type includes one or more of the following: straight line, concave side, and convex side.

5. The optical proximity correction method as described in claim 2, characterized in that, In the step of adjusting the position of the original evaluation point of the ideal contour at the defect along the normal direction of the ideal contour, the position of the newly added evaluation point is also adjusted along the normal direction of the ideal contour, which is suitable for increasing the absolute value of the edge placement error between the simulation contour and the ideal contour corresponding to the corrected graphic.

6. The optical proximity correction method as described in claim 1, characterized in that, The optical proximity correction method further includes: after detecting whether the corrected image has defects, and before adjusting the evaluation point where the ideal contour is located at the defect, obtaining defects with edge placement errors greater than or equal to a preset threshold as priority defects; The step of adjusting the evaluation point where the ideal contour is located at the defect includes: adjusting the evaluation point where the ideal contour is located at the location of the priority-processed defect.

7. The optical proximity correction method as described in claim 6, characterized in that, The preset threshold is 20nm.

8. The optical proximity correction method as described in claim 1, characterized in that, The steps for performing global adjustment processing on the corrected graphic include: using the adjustment evaluation point as the evaluation point of the ideal contour, updating the edge placement error cost function; and based on the updated edge placement error cost function, moving the evaluation point and the corresponding line segments around the evaluation point along the direction of the line segment normal.

9. The optical proximity correction method as described in claim 8, characterized in that, The edge placement error cost function is calculated based on the following formula: Where merit is the evaluation point, EPE is the edge placement error function, weight is the weight of the edge placement error function, and f(MRC) is the mask manufacturability rule constraint function.

10. The optical proximity correction method as described in claim 1, characterized in that, The step of determining whether the difference between the simulated contour and the ideal contour corresponding to the corrected graphic is within a preset range includes: using the original evaluation point as the evaluation point of the ideal contour, calculating the difference between the simulated contour and the ideal contour corresponding to the corrected graphic; and determining whether the difference is within a preset range.

11. The optical proximity correction method as described in claim 1, characterized in that, The optical proximity correction method further includes: when the corrected pattern is detected to have no defects, using the corrected pattern as a mask pattern.

12. The optical proximity correction method as described in claim 1, characterized in that, The steps of providing a corrected graphic after optical proximity correction processing include: providing a target graphic; obtaining an ideal contour based on the target graphic; and performing optical proximity correction processing on the target graphic based on the difference between the simulated contour and the ideal contour corresponding to the target graphic to obtain the corrected graphic.

13. The optical proximity correction method as described in claim 1, characterized in that, The step of adjusting the position of the original evaluation point of the ideal contour at the defect along the normal direction of the ideal contour includes: moving the original evaluation point at the defect along the normal of the ideal contour by a preset distance along the direction of increasing the absolute value of the edge placement error between the simulated contour and the ideal contour.

14. The optical proximity correction method as described in claim 13, characterized in that, The adjustment process further includes obtaining the preset distance before moving the original evaluation point along the normal of the ideal contour by a preset distance in the direction that increases the absolute value of the edge placement error between the simulated contour and the ideal contour.

15. The optical proximity correction method as described in claim 14, characterized in that, The step of obtaining the preset distance includes: performing one or more iterative simulation processing, wherein the simulation processing includes: moving the evaluation point along the direction of the ideal contour normal by a test step size in the direction of increasing the absolute value of the edge placement error between the simulated contour and the ideal contour; after moving the evaluation point along the direction of the ideal contour normal by a test step size, performing simulated optical proximity correction processing on the corrected graphic; and after performing simulated optical proximity correction processing, detecting the difference between the simulated contour and the ideal contour. When the difference between the simulated contour and the ideal contour is minimized, the corresponding test step size accumulation value is output as the preset distance.

16. The optical proximity correction method according to any one of claims 1 to 15, characterized in that, The distance between the original evaluation points is adjusted from 1 nm to 10 nm along the normal direction of the ideal profile.

17. An optical proximity correction system, characterized in that, include: A corrected graphic providing unit is used to provide a corrected graphic that has undergone optical proximity correction processing; The defect detection unit is used to detect whether the corrected graphic has defects. An evaluation point adjustment unit is used to adjust the evaluation point of the ideal contour located at the defect when a defect is detected in the corrected graphic, thereby obtaining an adjusted evaluation point. The adjustment process includes: adjusting the position of the original evaluation point of the ideal contour located at the defect along the normal direction of the ideal contour, which is suitable for increasing the absolute value of the edge placement error between the simulation contour and the ideal contour corresponding to the corrected graphic. The repair processing unit is used to perform one or more iterative repair processes on the corrected graphic after the adjustment process. Each repair process includes: using the adjustment evaluation point as the evaluation point of the ideal contour, performing global adjustment processing on the corrected graphic based on the difference between the simulated contour and the ideal contour corresponding to the corrected graphic; and determining whether the difference between the simulated contour and the ideal contour corresponding to the corrected graphic is within a preset range. The mask graphic output unit is used to determine that the repair process is complete when the difference between the simulated contour and the ideal contour corresponding to the corrected graphic is within a preset range, and outputs the corrected graphic after repair processing as the mask graphic.

18. A photomask, characterized in that, The mask includes a mask pattern formed by the optical proximity correction method as described in any one of claims 1-16.

19. A device, characterized in that, It includes at least one memory and at least one processor, the memory storing one or more computer instructions, wherein the one or more computer instructions are executed by the processor to implement the optical proximity correction method as described in any one of claims 1-16.

20. A storage medium, characterized in that, The storage medium stores one or more computer instructions for implementing the optical proximity correction method as described in any one of claims 1-16.

Images