Optical proximity correction method and mask manufacturing method

Abstract

An optical proximity correction method and a manufacturing method of a mask, wherein the optical proximity correction method comprises: obtaining an initial layout; performing exposure processing on the initial layout to obtain an initial exposure layout; when a defect is detected in the initial exposure layout, performing n times of detection optical proximity iterative correction on the initial layout with a preset minimum movement step; after the n times of detection optical proximity iterative correction, obtaining a plurality of optimal movement steps corresponding to a plurality of nth detection to-be-corrected edges, the optimal movement step being greater than or equal to the preset minimum movement step; and performing m times of first optical proximity iterative correction on an nth detection layout according to the plurality of optimal movement steps to obtain a first correction layout. Thus, the risk of defects occurring in the optical proximity correction process is reduced, and the efficiency of the optical proximity correction is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to an optical proximity correction method and a method for fabricating a photomask. Background Technology

[0002] Photolithography is a crucial technology in semiconductor manufacturing. It transfers patterns from a photomask to the surface of a silicon wafer, forming a semiconductor product that meets design requirements. The photolithography process includes an exposure step, a development step following exposure, and an etching step following development. In the exposure step, light passes through the light-transmitting areas of the photomask and shines onto the silicon wafer coated with photoresist. The photoresist undergoes a chemical reaction under the light. In the development step, the different solubility of the developer in the photoresist and the unphotoresisted photoresist creates a photolithographic pattern, thereby transferring the photomask pattern onto the photoresist.

[0003] In semiconductor manufacturing, as design dimensions continue to shrink and approach the limits of photolithography imaging systems, the diffraction effect of light becomes increasingly pronounced, leading to optical image degradation of the final design pattern. The actual photolithographic pattern formed is severely distorted relative to the pattern on the mask, resulting in a difference between the actual pattern formed on the silicon wafer and the design pattern. This phenomenon is called the optical proximity effect (OPE).

[0004] To correct the optical proximity effect, Optical Proximity Correction (OPC) was developed. The core idea of ​​OPC is to establish an optical proximity correction model based on the consideration of counteracting the optical proximity effect. The photomask pattern is designed according to the optical proximity correction model. In this way, although the lithographic pattern and the corresponding photomask pattern have optical proximity effect, the cancellation of this phenomenon has been considered when designing the photomask pattern according to the optical proximity correction model. Therefore, the lithographic pattern after photolithography is close to the target pattern actually desired by the user.

[0005] However, the efficiency of optical proximity correction in existing technologies still needs to be improved. Summary of the Invention

[0006] The technical problem solved by this invention is to provide an optical proximity correction method and a method for manufacturing a photomask, so as to reduce the risk of defects occurring during the optical proximity correction process and effectively improve the efficiency of optical proximity correction.

[0007] To solve the above-mentioned technical problems, the present invention provides an optical proximity correction method, comprising: obtaining an initial layout, the initial layout comprising a plurality of initial graphics; performing exposure processing on the initial layout to obtain an initial exposed layout; detecting defects in the initial exposed layout; providing a preset window and dividing the outlines of the plurality of initial graphics by the preset window to obtain a plurality of segments; when a defect is detected in the initial exposed layout, obtaining a plurality of initial edges to be corrected in the plurality of segments based on the detected defect; performing n iterations of optical proximity correction on the initial layout, where n is a natural number, and the method of the i-th iteration of optical proximity correction includes: moving a plurality of i-1th edges to be corrected in the (i-1)th detection layout by a preset minimum moving step size to form the i-th detection layout, where i is a natural number less than or equal to n. Furthermore, when i = 1, the (i-1)th detection pattern is the initial pattern, and the (i-1)th detection edge to be corrected is the initial edge to be corrected; the i-th detection pattern is subjected to the i-th defect detection step to obtain the i-th detection exposure pattern, and the i-th detection edge to be corrected is obtained in the i-th detection pattern; after the n-th detection optical proximity iteration correction, according to the initial pattern, the initial exposure pattern, the 1st to the nth detection patterns, and the 1st to the nth detection exposure patterns, the optimal moving step size corresponding one-to-one with the n-th detection edge to be corrected is obtained, and the optimal moving step size is greater than or equal to the preset minimum moving step size; according to the optimal moving step size corresponding one-to-one with the n-th detection edge to be corrected, the n-th detection pattern is subjected to m-th first optical proximity iteration corrections to obtain the first corrected pattern, where m is a natural number.

[0008] Optionally, the method for performing the i-th defect detection step on the i-th detection pattern includes: exposing the i-th detection pattern to obtain the i-th exposed detection pattern; detecting defects in the i-th exposed detection pattern; and obtaining a plurality of i-th detection edges to be corrected in the i-th detection pattern based on the defects detected in the i-th exposed detection pattern, wherein each i-th detection edge to be corrected corresponds to one of the plurality of (i-1)-th detection edges to be corrected.

[0009] Optionally, after the nth optical proximity iteration correction, the method for obtaining a plurality of optimal moving step sizes corresponding one-to-one with a plurality of nth detection edges to be corrected, based on the initial layout, initial exposure layout, the first to nth detection layouts, and the first to nth detection exposure layouts, includes: obtaining the edge placement error EPE0 of each initial edge to be corrected corresponding to a plurality of nth detection edges, based on the initial layout and initial exposure layout; and obtaining the edge placement error EPE1 to the edge placement error EPE1 corresponding to each nth detection edge to be corrected, based on the first to nth detection layouts and the first to nth detection exposure layouts. n The edge placement error EPE1 to the edge placement error EPE n Edge placement error (EPE) in i The method for obtaining the edge placement error (EPE) includes: based on the i-th probe layout and the i-th probe exposure layout, obtaining the edge placement error (EPE) of each i-th probe edge to be corrected corresponding to several n-th probe edges to be corrected. i According to the edge placement error EPE0 to the edge placement error EPE corresponding to each nth detected edge to be corrected. n Obtain the optimal movement step size for each nth edge to be probed and corrected.

[0010] Optionally, based on the edge placement error EPE0 to the edge placement error EPE corresponding to each nth detected edge to be corrected. n The method for obtaining the optimal movement step size for each nth edge to be corrected during detection includes: providing a preset maximum edge placement error (EPE) for each nth edge to be corrected during detection. SPEC Based on the preset maximum edge placement error EPE of each nth edge to be corrected during detection. SPEC The edge placement error EPE0 to the edge placement error EPE corresponding to each nth detected edge to be corrected n Obtain the optimal movement step size corresponding to each nth edge to be probed and corrected. The L min It is a preset minimum movement step size, the C i =EPE i -EPE i-1 The W i It is the C mentioned i The weighting coefficients, and

[0011] Optionally, the initial layout includes multiple unit areas, and the method for exposing the i-th detection layout to obtain the i-th detection exposed layout includes: in the i-th detection layout, obtaining a plurality of i-th detection areas to be exposed, each i-th detection area to be exposed corresponding to one unit area, and a plurality of (i-1)-th detection edges to be corrected after moving by the preset minimum moving step size are located within the plurality of i-th detection areas to be exposed; exposing the plurality of i-th detection areas to be exposed to obtain an exposed layout of the plurality of i-th detection areas to be exposed; modifying the (i-1)-th detection exposed layout according to the exposed layout of the plurality of i-th detection areas to form the i-th detection exposed layout, where when i=1, the (i-1)-th detection exposed layout is the initial exposed layout.

[0012] Optionally, the method for performing the kth iteration of the m-th first optical proximity iteration correction includes: moving several initial (k-1)th edges to be corrected in the initial (k-1)th correction pattern by their respective optimal moving step sizes to form an initial kth correction pattern, where k is a natural number less than or equal to m. Specifically, when k = 1, the initial (k-1)th correction pattern is the nth detection pattern, and the several initial (k-1)th edges to be corrected are the several nth detection edges to be corrected; when k > 1, each initial (k-1)th edge to be corrected corresponds to one of the several nth detection edges to be corrected; when k = m, the formed initial mth correction pattern is the first correction pattern; performing exposure processing on the initial kth correction pattern to obtain an initial kth exposure correction pattern; performing defect detection on the initial kth exposure correction pattern; when a defect is detected in the initial kth exposure correction pattern, obtaining several initial kth edges to be corrected in the initial kth correction pattern based on the detected defect, and when k < m, each initial kth edge to be corrected corresponds to one of the several nth detection edges to be corrected.

[0013] Optionally, the method for performing the kth iteration of the m-th first optical proximity iteration correction further includes: stopping the first optical proximity iteration correction when no defect is detected in the initial k-th exposure correction pattern.

[0014] Optionally, the initial layout includes multiple cell regions; when k is less than m, the initial k-th corrected layout is exposed to obtain the initial k-th exposure corrected layout by the following method: in the initial k-th corrected layout, a plurality of initial k-th exposure areas are obtained, each initial k-th exposure area corresponds to one cell region, and the plurality of initial (k-1)-th correction edges after moving their respective optimal moving step sizes are located within the plurality of initial k-th exposure areas; the plurality of initial k-th correction areas in the initial k-th corrected layout are exposed to obtain the exposure layout of the plurality of initial k-th correction areas; the initial (k-1)-th exposure corrected layout is modified according to the exposure layout of the plurality of initial k-th correction areas to form the initial k-th exposure corrected layout, and when k = 1, the initial (k-1)-th exposure corrected layout is the nth detection exposure layout.

[0015] Optionally, when k equals m, the method for exposing the initial k-th corrected image to obtain the initial k-th exposure corrected image includes: performing global exposure on the first corrected image to obtain the first exposure corrected image.

[0016] Optionally, it also includes: when a defect is detected in the first corrected layout, performing a number of second optical proximity iterations on the first corrected layout according to a preset minimum moving step size to obtain a second corrected layout.

[0017] Optionally, the preset minimum moving step size is 0.1 nanometers.

[0018] Optionally, n is greater than or equal to 2, and n is less than or equal to 5.

[0019] Optionally, the method for obtaining the initial layout includes: providing a target layout; performing several initial optical proximity iterations on the target layout to obtain the initial layout.

[0020] Accordingly, the technical solution of the present invention also provides a method for fabricating a photomask, comprising: obtaining an initial pattern, the initial pattern comprising a plurality of initial graphics; exposing the initial pattern to obtain an initial exposed pattern; detecting defects in the initial exposed pattern; providing a preset window and dividing the outlines of the plurality of initial graphics by the preset window to obtain a plurality of segments; when a defect is detected in the initial exposed pattern, obtaining a plurality of initial edges to be corrected in the plurality of segments based on the defect detected in the initial exposed pattern; performing n iterations of optical proximity correction on the initial pattern, where n is a natural number, and the method of the i-th iteration of optical proximity correction includes: moving a plurality of i-1th edges to be corrected in the (i-1)th detection pattern by a preset minimum moving step size to form the i-th detection pattern, where i is a natural number less than or equal to n, and when i = 1, The (i-1)th detection pattern is the initial pattern, and the (i-1)th detection edges to be corrected are the initial edges to be corrected. The i-th detection pattern undergoes the i-th defect detection step to obtain the i-th detection exposure pattern, and the i-th detection edges to be corrected are obtained from the i-th detection pattern. After the n-th detection optical proximity iteration correction, based on the initial pattern, the initial exposure pattern, the 1st to nth detection patterns, and the 1st to nth detection exposure patterns, several optimal moving step sizes corresponding one-to-one with the nth detection edges to be corrected are obtained, where the optimal moving step size is greater than or equal to the preset minimum moving step size. Based on the several optimal moving step sizes corresponding one-to-one with the nth detection edges to be corrected, the n-th detection pattern undergoes m-th first optical proximity iteration corrections to obtain the first corrected pattern, where m is a natural number. A mask is fabricated based on the first corrected pattern.

[0021] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects:

[0022] In the optical proximity correction method provided by the technical solution of the present invention, during the process of n detection optical proximity iteration corrections on the initial layout, when a defect is detected in the initial exposure layout, several initial edges to be corrected are obtained from the several segments based on the defect detected in the initial exposure layout; the initial layout is subjected to n detection optical proximity iteration corrections, where n is a natural number, and the method of the i-th detection optical proximity iteration correction includes: moving several i-1 detection edges to be corrected in the i-1-th detection layout by a preset minimum moving step to form the i-th detection layout, where i is a natural number less than or equal to n, and when i = 1, the i-1-th detection layout is the initial layout, and the several i-1 detection edges to be corrected are several initial edges to be corrected; the i-th detection layout is subjected to the i-th defect detection step to obtain the i-th detection exposure layout, and, in the i-th... Several i-th detection edges to be corrected are obtained from the detection pattern. After the nth optical proximity iteration correction, based on the initial pattern, the initial exposure pattern, the first to nth detection patterns, and the first to nth exposure patterns, several optimal moving step sizes corresponding one-to-one with the several n-th detection edges to be corrected are obtained. The optimal moving step size is greater than or equal to the preset minimum moving step size. Based on the several optimal moving step sizes corresponding one-to-one with the several n-th detection edges to be corrected, the n-th detection pattern is subjected to m first optical proximity iteration corrections to obtain a first corrected pattern. Therefore, the risk of defects occurring in the first optical proximity iteration correction can be reduced. At the same time, a first corrected pattern within the preset deviation range is obtained with fewer first optical proximity iteration corrections, thereby reducing the risk of defects occurring during the optical proximity correction process and effectively improving the efficiency of the optical proximity correction. Specifically, the optimal moving step size is greater than or equal to the preset minimum moving step size (the minimum edge shifting distance that can be used in the correction process), that is, the preset minimum moving step size is smaller than the optimal moving step size. By using a small preset minimum moving step size and a small number of optical proximity iteration corrections (n ​​detection optical proximity iteration corrections), the response relationship between the moving step size of each nth detection edge to be corrected and the moving step size of each nth detection edge to be corrected after exposure processing is detected. This allows for the acquisition of the larger optimal moving step size for each of the nth detection edges to be corrected while ensuring relatively similar convergence speeds. This allows for appropriate adjustment of the moving step size in the first optical proximity iteration correction. Therefore, on the one hand, a larger optimal moving step size reduces the number of times the first optical proximity iteration correction needs to be performed; on the other hand, during the first optical proximity iteration correction, the convergence speed of each edge to be corrected is similar, resulting in fewer or no jumps and other defects, thus reducing or avoiding the additional optical proximity iteration corrections required to correct these jumps and other defects.Therefore, the risk of defects occurring during optical proximity correction is reduced, and the overall number of optical proximity correction iterations required to obtain the first corrected pattern is reduced. Attached Figure Description

[0023] Figure 1 This is a schematic flowchart of an optical proximity correction method according to an embodiment of the present invention;

[0024] Figures 2 to 9 This is a schematic diagram of the various steps of an optical proximity correction method according to an embodiment of the present invention;

[0025] Figure 10 This is a flowchart illustrating the method for the i-th detection optical proximity iteration correction in one embodiment of the present invention;

[0026] Figure 11 This is a flowchart illustrating the method for the i-th defect detection in one embodiment of the present invention;

[0027] Figure 12 This is a flowchart illustrating a method for obtaining the optimal movement step size according to an embodiment of the present invention;

[0028] Figure 13 This is a flowchart illustrating the method of step S630 in one embodiment of the present invention;

[0029] Figure 14 This is a flowchart illustrating a first optical proximity iterative correction method according to an embodiment of the present invention;

[0030] Figure 15 This is a flowchart illustrating a method for obtaining an initial k-th exposure correction pattern according to an embodiment of the present invention. Detailed Implementation

[0031] As described in the background section, the efficiency of optical proximity correction in the prior art still needs to be improved. The following will provide a detailed explanation with reference to specific embodiments.

[0032] An existing optical proximity correction method includes the following steps:

[0033] Step S10: Provide the target map;

[0034] Step S11: Exposure processing is performed on the target map to obtain the initial exposure map;

[0035] Step S12: Detect defects in the initial exposure pattern and obtain the initial fragment to be corrected in the target pattern based on the defects in the initial exposure pattern.

[0036] Step S20: After step S12, perform Q optical proximity iterations based on the target layout to obtain the corrected layout.

[0037] In step S20, the method for performing the p-th iteration of the Q-th optical proximity correction includes:

[0038] S21, in the p-1th layout, multiple p-1th edges to be corrected are moved by a preset step size to form the pth layout, where p is a natural number. When p = 1, the 0th layout is the target layout, and the p-1th edge to be corrected is the initial edge to be corrected.

[0039] S22, perform exposure processing on the p-th map to obtain the corresponding p-th exposed map;

[0040] S23, detect defects in the p-th exposure pattern, and obtain several p-th edges to be corrected in the p-th pattern based on the defects in the p-th exposure pattern.

[0041] However, after moving each (p-1)th edge to be corrected by the same preset step size, the moving step sizes of the edges corresponding to each (p-1)th edge to be corrected in the p-th exposure pattern obtained after exposure processing are not the same. That is, under the same preset step size, the convergence speeds corresponding to each (p-1)th edge to be corrected are different. Therefore, new defects such as jumps can easily occur in optical proximity iteration correction. This necessitates increasing the number of optical proximity iterations to correct these new defects, resulting in poor efficiency of the aforementioned optical proximity correction method.

[0042] In another optical proximity correction method, by reducing the preset step size, the convergence speed of each (p-1)th edge to be corrected is reduced overall, making the convergence speed of each (p-1)th edge to be corrected relatively small. This reduces new defects such as jumps caused by different convergence speeds of the (p-1)th edges to be corrected. However, because the preset step size is reduced, more optical proximity iterations are required to correct the defects that would have occurred after the target pattern exposure process. Therefore, the number of optical proximity iterations is also increased, resulting in poor efficiency of the optical proximity correction method.

[0043] To address the aforementioned technical problems, the present invention provides an optical proximity correction method and a method for fabricating a photomask. By performing n iterations of optical proximity correction on an initial pattern with a preset minimum step size, and after these n iterations, obtaining several optimal step sizes corresponding one-to-one with several nth edge to be corrected, where each optimal step size is greater than or equal to the preset minimum step size, the risk of defects occurring during the first optical proximity correction can be reduced when performing m iterations of first optical proximity correction on the nth pattern according to these optimal step sizes. Furthermore, obtaining a first corrected pattern within a preset deviation range with fewer iterations of first optical proximity correction reduces the risk of defects during the optical proximity correction process and effectively improves the efficiency of optical proximity correction.

[0044] To make the above-mentioned objectives, features and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0045] Figure 1 This is a schematic flowchart of an optical proximity correction method according to an embodiment of the present invention.

[0046] Please refer to Figure 1 The optical proximity correction method includes:

[0047] Step S100: Obtain an initial layout, wherein the initial layout includes several initial graphics;

[0048] Step S200: Exposure processing is performed on the initial layout to obtain the initial exposed layout;

[0049] Step S300: Detect defects in the initial exposure pattern;

[0050] Step S900: Provide a preset window and use the preset window to divide the outlines of the several initial graphics to obtain several segments;

[0051] When a defect is detected in the initial exposure layout, step S400 is executed to obtain a plurality of initial edges to be corrected in the plurality of segments based on the defect detected in the initial exposure layout.

[0052] Execute step S500, and perform n detection optical proximity iteration corrections on the initial layout according to the preset minimum moving step size, to obtain several nth detection edge to be corrected, the first detection layout to the nth detection layout, and the first detection exposure layout to the nth detection exposure layout.

[0053] Step S600: After the nth detection optical proximity iteration correction, based on the initial layout, initial exposure layout, first detection layout to nth detection layout, and first detection exposure layout to nth detection exposure layout, obtain a number of optimal moving step sizes corresponding one-to-one with a number of nth detection edges to be corrected, wherein the optimal moving step size is greater than or equal to the preset minimum moving step size.

[0054] Step S700: Based on several optimal moving step sizes that correspond one-to-one with several nth detection edges to be corrected, perform m first optical proximity iterations to correct the nth detection pattern to obtain the first corrected pattern.

[0055] The following describes each step of the optical proximity correction method in detail with reference to the accompanying drawings.

[0056] Figures 2 to 9 This is a schematic diagram of the various steps of an optical proximity correction method according to an embodiment of the present invention.

[0057] Please refer to Figure 2 Obtain the initial map 100.

[0058] The initial layout 100 includes several initial graphics 101.

[0059] In this embodiment, the initial layout 100 is a target layout directly provided by those skilled in the art, and the initial graphic 101 is the target graphic.

[0060] In another embodiment, the method for obtaining an initial layout includes: step S110, providing a target layout; step S120, performing a number of initial optical proximity iterations on the target layout; and step S130, stopping the initial optical proximity iterations when a preset number of initial optical proximity iterations is reached, thereby obtaining the initial layout.

[0061] Specifically, for step S110, the target layout includes several target graphics.

[0062] Meanwhile, in step S120, the method for performing several initial optical proximity iterations on the target layout includes: step S121, exposing the (v-1)th target layout to obtain the (v-1)th target exposed layout, wherein when v = 1, the (v-1)th target exposed layout is the target layout provided in step S110; step S122, detecting defects in the (v-1)th target exposed layout; step S123, obtaining several corresponding vth target edges to be corrected based on the defects detected in the (v-1)th target exposed layout; step S124, shifting the several vth target edges to be corrected in the (v-1)th target layout to form the vth target layout.

[0063] The variable v is a natural number, and v is less than or equal to the preset number of initial optical proximity iterations. Furthermore, regarding step S124, when v equals the preset number of initial optical proximity iterations, the v-th target layout is the initial layout.

[0064] Since the initial layout is obtained through the initial optical proximity iteration correction steps and before the first optical proximity iteration correction, some defects in the initial layout are preliminarily corrected before the subsequent more refined correction process. This improves the targeting of the entire optical proximity correction method, makes the layout corrected by the optical proximity correction method more accurate, and helps to further improve the efficiency of the optical proximity correction method.

[0065] In this embodiment, the initial layout 100 also includes a plurality of unit regions 101a.

[0066] It is important to understand that, for ease of understanding, Figure 2 The diagram only schematically shows a portion of the unit area 101a and the initial pattern 101. The shape and number of the unit area 101a and the initial pattern 101 should not be considered as features that limit the scope of protection of this invention.

[0067] Please refer to Figure 3 The initial layout 100 is exposed to obtain the initial exposed layout 110.

[0068] It should be noted that all exposure processes involved in this embodiment refer to exposure processes performed through simulation. This improves the convenience and efficiency of the optical proximity correction method and reduces the material and other costs associated with it.

[0069] In other embodiments, the exposure processing may also be actual exposure processing.

[0070] The initial exposure pattern 110 includes a plurality of initial exposure patterns 111 corresponding to a plurality of initial patterns 101.

[0071] It should be noted that, for ease of understanding, Figure 3 The outline of part of the initial graphic 101 in the initial layout 100 is shown in dashed lines.

[0072] In this embodiment, the exposure processing performed on the initial layout 100 is a global exposure processing of the entire initial layout 100.

[0073] Please continue to refer to this. Figure 3 , to detect defects in the initial exposure pattern 110.

[0074] The defect refers to the deviation from the expected portion in the initial exposure layout 110 compared to the initial layout 100.

[0075] Such defects include, for example, edge placement error (EPE) and contactend that exceed a preset deviation between the initial exposure layout 110 and the initial layout 100.

[0076] Please refer to Figure 4 A preset window (not shown) is provided, and the outlines of the several initial graphics 101 are divided by the preset window to obtain several segments (not shown).

[0077] Specifically, in optical proximity correction, the outlines of several initial graphics 101 are typically segmented into several fragments through windows of a preset size.

[0078] Please continue to refer to this. Figure 4 When a defect is detected in the initial exposure layout, a number of initial edges 102 to be corrected are obtained in a number of segments based on the defect detected in the initial exposure layout 110.

[0079] The initial edge to be corrected 102 refers to one or more consecutive segments in the initial graphic 101 that correspond to the position of the defect.

[0080] The location of the defect refers to the location of the sampling point or the area where the defect occurs in the initial exposure layout 110. The location can be represented by coordinates or other means. One or more consecutive segments corresponding to the location of the defect refer to the segments contained in the modified area formed based on the location of the sampling point or the sampling area in the initial layout 100, or the segments touched by the outline of the modified area. The method for forming the modified area based on the location of the sampling point or the sampling area includes: forming a range with a preset size centered on the sampling point, or expanding the outline of the adopted area by a preset size, etc.

[0081] It should be understood that those skilled in the art can select a method for obtaining one or more consecutive segments corresponding to the location of the defect, based on actual equipment capabilities and design requirements. That is, they can choose a method for obtaining a plurality of initial edges 102 to be corrected in the initial layout 100 based on the defects detected in the initial exposure layout 110. Therefore, the specific method for obtaining a plurality of initial edges 102 to be corrected in the initial layout 100 based on the defects detected in the initial exposure layout 110 should not be considered a feature that limits the scope of protection of this invention.

[0082] It should be noted that, for ease of explanation, Figure 4 The image only schematically shows two initial edges 102 to be corrected on an initial shape 101.

[0083] Please refer to Figure 10 , Figure 10 This is a flowchart illustrating the method for the i-th detection optical proximity iteration correction in an embodiment of the present invention. For step S500, in the n-th detection optical proximity iteration correction, the method for the i-th detection optical proximity iteration correction includes: step S510, performing the i-th detection correction step with a preset minimum moving step size to obtain the i-th detection pattern.

[0084] Where n is a natural number, and i is a natural number less than or equal to n.

[0085] Specifically, for step S510, the method of performing the i-th detection correction step with a preset minimum moving step size to obtain the i-th detection layout includes: moving several i-1 detection edges to be corrected in the (i-1)-th detection layout by the preset minimum moving step size to form the i-th detection layout.

[0086] When i = 1, the 0th probe layout is the initial layout 100, and the 0th probe edge to be corrected is the initial edge to be corrected 102.

[0087] It is important to understand that the 0th probe layout is the (i-1)th probe layout when i=1, and the 0th probe edge to be corrected is the (i-1)th probe edge to be corrected when i=1.

[0088] When i is greater than 1, the (i-1)th detection pattern refers to the corresponding detection pattern formed during the detection correction step in the previous (i-1)th detection optical proximity iteration correction. Several (i-1)th detection edges to be corrected refer to several corresponding edges to be corrected obtained during the defect detection step in the previous (i-1)th detection optical proximity iteration correction (please refer to the relevant explanation in the subsequent i-th step).

[0089] In this embodiment, the i-th detection pattern includes: a plurality of i-th detection patterns corresponding to a plurality of initial patterns 101.

[0090] The preset minimum movement step size refers to the minimum movement distance that can be used when moving each edge to be corrected (i.e., several edges to be corrected from the 0th to the (n-1)th) during the n detection and correction steps. This ensures high accuracy in achieving the optimal movement step size.

[0091] Thus, starting with the initial layout 100 and several initial edges to be corrected 102, by using the preset minimum moving step size as the moving distance in the nth detection and correction steps, several 0th detection edges to be corrected are moved to several (n-1)th detection edges to be corrected, forming the corresponding 1st to nth detection layouts.

[0092] It should be understood that during the n detection and correction steps, the direction of movement of each detected edge to be corrected needs to be determined based on the detected defect. The specific direction of movement of each detected edge to be corrected should not be a feature that limits the scope of protection of this invention.

[0093] In this embodiment, the preset minimum movement step size L1 is a side-moving distance that is less than or equal to any optimal movement step size (described later).

[0094] The smaller the preset minimum moving step size L1, the higher the accuracy of each optimal moving step size obtained based on n detection optical proximity iterations.

[0095] In this embodiment, the preset minimum movement step size is 0.1 nanometers.

[0096] Please continue to refer to this. Figure 10 For step S500, in the nth detection optical proximity iteration correction, the method for the i-th detection optical proximity iteration correction further includes: step S520, performing the i-th defect detection step on the i-th detection pattern to obtain the i-th detection exposure pattern, and obtaining a number of i-th detection edges to be corrected in the i-th detection pattern.

[0097] Please refer to Figure 11 , Figure 11 This is a flowchart illustrating the method for the i-th defect detection in one embodiment of the present invention. In this embodiment, the method for performing the i-th defect detection step on the i-th probe pattern in step S520 includes: step S521, exposing the i-th probe pattern to obtain the i-th probe exposed pattern.

[0098] In this embodiment, the method for obtaining the i-th exposed detection pattern by performing exposure processing on the i-th detection pattern in step S521 includes:

[0099] Step S5211: In the i-th detection pattern, obtain a plurality of i-th detection exposure areas, each i-th detection exposure area corresponds to 1 unit area, and the plurality of (i-1)-th detection correction edges after moving the preset minimum moving step are located within the plurality of i-th detection exposure areas.

[0100] Step S5212: Exposure processing is performed on the plurality of i-th detection areas to be exposed to obtain an exposure pattern of the plurality of i-th detection areas to be exposed.

[0101] Step S5213: Based on the exposure patterns of several i-th detection areas to be exposed, modify the (i-1)-th detection exposure pattern to form the i-th detection exposure pattern.

[0102] When i = 1, the (i-1)th detection exposure pattern (i.e. the 0th exposure pattern) is the initial exposure pattern.

[0103] Specifically, the i-th probe layout includes the initial layout 100 (e.g., Figure 2 Each unit region 101a (as shown) Figure 2 (As shown) corresponds to the i-th unit region.

[0104] Each i-th detection area to be exposed refers to the i-th unit area where the (i-1)-th detection edge to be corrected is located after moving the preset minimum moving step size in the i-th detection layout.

[0105] It should be understood that an i-th unit region may include one (i-1)-th probe edge to be corrected after moving a preset minimum step size, or it may include two or more (i-1)-th probe edges to be corrected after moving a preset minimum step size.

[0106] Without extensive modifications to each detection pattern, the risk of optical proximity effects arising from the movement of each detection edge to be modified is relatively small for each detection pattern (from the 1st to the nth detection pattern) in regions that are far from each detection edge to be modified.

[0107] Based on this, since exposure processing is performed on several ith-th detection exposure areas (several ith-th unit areas where several ith-1 detection correction edges are located after moving a preset minimum step size), exposure patterns of several ith-th detection exposure areas are obtained. Furthermore, based on the exposure patterns of several ith-th detection exposure areas, the (i-1)th detection exposure pattern is modified to form the ith-th detection exposure pattern. Therefore, compared with global exposure processing, forming detection exposure patterns through targeted regional exposure processing can greatly improve the efficiency of the entire detection optical proximity iterative correction process. At the same time, it also takes into account the detection exposure pattern that is similar to or the same as the exposure pattern obtained after global exposure processing, that is, it takes into account both the accuracy of defect detection in detection optical proximity iterative correction and the accuracy of the subsequent acquisition of the optimal moving step size.

[0108] In other embodiments, the method for performing the i-th defect detection step on the i-th detection pattern in step S520 includes: performing global exposure processing on the i-th detection pattern to obtain the i-th exposed detection pattern.

[0109] In this embodiment, the i-th detection exposure pattern includes several i-th detection exposure patterns corresponding to the i-th detection pattern.

[0110] Please continue to refer to this. Figure 11 In this embodiment, the method for performing the i-th defect detection step on the i-th probe pattern in step S520 further includes: step S522, detecting defects in the i-th probe exposure pattern.

[0111] For an explanation of the defects described in step S522, please refer to the aforementioned explanation of the defects in the initial exposure layout 110, which will not be repeated here.

[0112] It is important to understand that the defects detected in the i-th detection exposure pattern and the defects in the initial exposure pattern 110 are not necessarily in a one-to-one correspondence. Specifically, since each of the n detection optical proximity iterations includes a detection correction step, some defects in the initial exposure pattern 110 may have already been corrected before the current (i-th) detection optical proximity iteration.

[0113] Please continue to refer to this. Figure 11 In this embodiment, the method for performing the i-th defect detection step on the i-th detection pattern in step S520 further includes: step S523, obtaining a plurality of i-th detection edges to be corrected in the i-th detection pattern based on the defects detected in the i-th detection exposure pattern, wherein each i-th detection edge to be corrected corresponds to one of the plurality of (i-1)-th detection edges to be corrected.

[0114] Specifically, the method for obtaining several i-th detection edges to be corrected in the i-th detection pattern based on the defects detected in the i-th detection exposure pattern includes: dividing the outline of the several i-th detection patterns with a preset window to obtain several corresponding segments; and obtaining several i-th detection edges to be corrected in the corresponding segments based on the defects detected in the i-th detection pattern.

[0115] To facilitate understanding, we will take the first detection optical proximity iteration correction as an example.

[0116] Please refer to Figure 5 and Figure 6 , Figure 6 yes Figure 5 A magnified schematic diagram of the central region Z. When i=1, the first detection correction step is performed with a preset minimum moving step size L1 to obtain the first detection pattern 210.

[0117] In this embodiment, the method of performing the first detection correction step with a preset minimum moving step size L1 to obtain the first detection layout 210 includes: moving a plurality of the zero detection edges to be corrected in the zero detection layout by a preset minimum moving step size L1 to form the first detection layout 210.

[0118] In this embodiment, the 0th detection layout is the initial layout 100, and the plurality of 0th detection edges to be corrected are the plurality of initial edges to be corrected 102.

[0119] The first detection pattern 210 includes a first detection pattern 211 corresponding to a plurality of initial patterns 101.

[0120] In this embodiment, the first detection pattern 210 further includes a plurality of first unit regions 210a that correspond one-to-one with each unit region 101a of the initial pattern 100.

[0121] It should be noted that, for ease of understanding, Figure 6 The two initial edges 102 to be corrected before the preset minimum movement step size L1 are schematically represented by dashed lines.

[0122] Next, a first defect detection step is performed on the first detection pattern 210 to obtain a first detection exposure pattern, and several first detection edges to be corrected are obtained in the first detection pattern 210. Please refer to the schematic diagram of the structure for the specific implementation of the first defect detection step. Figures 6 to 7 .

[0123] Please refer to Figure 7 Exposure processing is performed on the first detection pattern 210 to obtain the first detection exposure pattern 310.

[0124] In this embodiment, the method for performing exposure processing on the first detection pattern to obtain the first detection exposure pattern 310 includes:

[0125] In the first detection pattern, several first detection exposure areas (not shown) are obtained, each first detection exposure area is associated with one unit area 101a (e.g., Figure 2 As shown, the initial edges 102 to be corrected after moving the preset minimum moving step L1 are located within the first detection exposure areas; the exposure processing is performed on the first detection exposure areas to obtain the exposure pattern of the first detection exposure areas (not shown); based on the exposure pattern of the first detection exposure areas, the initial exposure pattern 110 is modified to form the first detection exposure pattern 310.

[0126] The first detection area to be exposed refers to the first unit area 210a where the first initial edge to be corrected 102 is located after the preset minimum moving step size L1 is moved.

[0127] Modifying the initial exposure pattern 110 based on the exposure patterns of several first detection exposure areas means replacing a portion of the initial exposure pattern 110 of the corresponding area in the initial exposure pattern 110 with the exposure patterns of several first detection exposure areas. This forms the first detection exposure pattern 310.

[0128] The corresponding area in the initial exposure pattern 110 refers to the area in the initial exposure pattern 110 corresponding to the unit area 101a corresponding to the first detection area to be exposed.

[0129] In this embodiment, the first detection exposure pattern 310 includes a plurality of first detection exposure patterns 311 corresponding to the first detection pattern 211.

[0130] It should be noted that, for ease of understanding and explanation, Figure 7 The diagram schematically shows a first detection exposure pattern 311, and the outline of the first detection pattern 211 corresponding to the first detection exposure pattern 311 is shown in dashed lines.

[0131] Please continue to refer to this. Figure 7Detects defects (not shown) in the first detection exposure pattern 310.

[0132] Please refer to Figure 8 Based on the defects detected in the first detection exposure pattern 310, a plurality of first detection correction edges 212 are obtained in the first detection pattern 210, each first detection correction edge 212 corresponding to one of the plurality of initial correction edges 102.

[0133] In this embodiment, the method for obtaining a plurality of first detection edges 212 to be corrected in the first detection pattern 210 includes: dividing the outline of the plurality of first detection patterns 211 by a preset window to obtain a plurality of corresponding segments; and obtaining a plurality of first detection edges 212 to be corrected in the corresponding segments according to the defects detected in the first detection patterns.

[0134] Thus, the first iteration of the n-times optical proximity correction for detection was achieved.

[0135] It should be noted that, for ease of understanding, Figure 8 The two initial edges 102 to be corrected are schematically represented by dashed lines. Preferably, n is greater than or equal to 2 and less than or equal to 5.

[0136] If n is too large, the number of optical proximity iterations for correction will be too high with a small preset minimum step size L1, resulting in reduced efficiency. If n is too small, the number of optical proximity iterations for correction will be too low with a small preset minimum step size L1, leading to poor accuracy of the obtained optimal step size. Therefore, using a suitable n, i.e., n is greater than or equal to 2 and less than or equal to 5, can achieve both high efficiency of optical proximity correction and good accuracy of the optimal step size.

[0137] Next, after the nth optical proximity iteration correction, based on the initial pattern 100, the initial exposure pattern 110, the first detection pattern 210 to the nth detection pattern (not shown), and the first detection exposure pattern 310 to the nth detection exposure pattern (not shown), several optimal moving step sizes L2 corresponding one-to-one with several nth detection edges to be corrected (not shown) are obtained.

[0138] The optimal step size L2 is greater than or equal to the preset minimum step size L1.

[0139] Please refer to Figure 12 , Figure 12This is a flowchart illustrating a method for obtaining the optimal moving step size according to an embodiment of the present invention. Regarding step S600, after the nth optical proximity iteration correction, the method for obtaining several optimal moving step sizes corresponding one-to-one with several nth detection edges to be corrected, based on the initial layout, initial exposure layout, the first to nth detection layouts, and the first to nth detection exposure layouts, includes: step S610, obtaining the edge placement error EPE0 of each initial edge to be corrected corresponding to several nth detection edges to be corrected, based on the initial layout and the initial exposure layout.

[0140] Please refer to Figure 9 Based on the initial layout 100 and the initial exposure layout 110, the edge placement error EPE0 of each initial edge to be corrected 102 corresponding to several nth probe edges to be corrected is obtained.

[0141] In this embodiment, the edge placement error EPE0 is obtained by the deviation between the sampling point on the initial edge to be corrected 102 and the sampling point on the contour of the initial exposure pattern 111.

[0142] It should be understood that those skilled in the art can choose the specific method for obtaining the edge placement error EPE0 according to actual needs. Therefore, the specific method for obtaining the edge placement error EPE0 should not be considered a feature that limits the scope of protection of this invention.

[0143] It should be noted that, for ease of understanding, Figure 9 The two initial edges 102 to be corrected are shown only schematically, and the corresponding edge placement error EPE0 is also shown only schematically.

[0144] Please continue to refer to this. Figure 12 Regarding step S600, after the nth optical proximity iteration correction, the method for obtaining several optimal moving step sizes corresponding one-to-one with several nth detection edges to be corrected based on the initial layout, initial exposure layout, the first detection layout to the nth detection layout, and the first detection exposure layout to the nth detection exposure layout further includes: step S620, obtaining the edge placement error EPE1 to the edge placement error EPE corresponding to each nth detection edge to be corrected based on the first detection layout to the nth detection layout, and the first detection exposure layout to the nth detection exposure layout. n .

[0145] Specifically, the edge placement error EPE1 to the edge placement error EPE n Edge placement error (EPE) in i The method for obtaining the edge placement error (EPE) includes: based on the i-th probe layout and the i-th probe exposure layout, obtaining the edge placement error (EPE) of each i-th probe edge to be corrected corresponding to several n-th probe edges to be corrected. i .

[0146] In this embodiment, based on the i-th detector layout and the i-th detector exposure layout, the edge placement error EPE of each i-th detector to be corrected edge corresponding to several n-th detector to be corrected edges is obtained. i For the method described above, please refer to step S610, which describes how to obtain the edge placement error EPE0 of each initial edge to be corrected corresponding to several nth edge to be corrected by detection based on the initial layout and the initial exposure layout. It will not be repeated here.

[0147] Please continue to refer to this. Figure 12 Regarding step S600, after the nth optical proximity iteration correction, the method for obtaining several optimal moving step sizes corresponding one-to-one with several nth detection edges to be corrected, based on the initial layout, initial exposure layout, the first detection layout to the nth detection layout, and the first detection exposure layout to the nth detection exposure layout, further includes: step S630, based on the edge placement error EPE0 to the edge placement error EPE corresponding to each nth detection edge to be corrected. n Obtain the optimal movement step size for each nth edge to be probed and corrected.

[0148] Please refer to Figure 13 , Figure 13 This is a flowchart illustrating step S630 of an embodiment of the present invention. For step S630, the method is based on the edge placement error EPE0 to the edge placement error EPE corresponding to each nth detected edge to be corrected. n Methods for obtaining the optimal movement step size for each nth edge to be probed and corrected include:

[0149] Step S631: Provide a preset maximum edge placement error EPE for each nth detected edge to be corrected. SPEC ;

[0150] Step S632, based on the preset maximum edge placement error EPE of each nth detected edge to be corrected. SPEC The edge placement error EPE0 to the edge placement error EPE corresponding to each nth detected edge to be corrected n Obtain the optimal movement step size corresponding to each nth edge to be probed and corrected.

[0151] The L min It is the preset minimum movement step size, and C i =EPE i -EPE i-1 The W i It is the C mentioned i The weighting coefficients, and

[0152] Therefore, by using a small preset minimum moving step size and a small number of optical proximity iteration corrections (n ​​detection optical proximity iteration corrections), the response relationship between the moving step size (moving distance) of each nth detection edge to be corrected and the moving distance of each exposure pattern contour corresponding to each nth detection edge to be corrected after exposure processing was detected. This enabled the acquisition of the larger optimal moving step size L2 for each of the nth detection edges to be corrected in the subsequent first optical proximity iteration correction, while taking into account that they have relatively similar convergence speeds.

[0153] Please continue to refer to this. Figure 1 Based on several optimal moving step sizes L2 that correspond one-to-one with several nth detection edges to be corrected, the nth detection pattern is subjected to m first optical proximity iterations to obtain the first corrected pattern.

[0154] m is a natural number.

[0155] Because during the n-times optical proximity iteration correction of the initial pattern, a preset minimum movement step size L1 is used for the i-th detection correction step to obtain the i-th detection pattern, and after the n-times optical proximity iteration correction, based on the initial pattern, the initial exposure pattern, the first to n-th detection patterns, and the first to n-th exposure patterns, several optimal movement step sizes L2 corresponding one-to-one with several n-th detection edges to be corrected are obtained, and based on the several optimal movement step sizes L2 corresponding one-to-one with several n-th detection edges to be corrected, the n-th detection pattern is subjected to m-times of first optical proximity iteration correction to obtain the first corrected pattern, thus effectively improving the efficiency of optical proximity correction.

[0156] Specifically, the optimal step size L2 is greater than or equal to the preset minimum step size L1, that is, the preset minimum step size L1 is smaller than the optimal step size L2.

[0157] By using a small preset minimum moving step size L1 and a small number of optical proximity iterations (n ​​detection optical proximity iterations), the response relationship between the moving step size (edge ​​shift distance) of each nth detection edge to be corrected and the shift distance of each exposure pattern contour corresponding to each nth detection edge to be corrected after exposure processing is detected. Thus, the larger optimal moving step size L2 corresponding to each of the nth detection edges to be corrected, while ensuring relatively similar convergence speeds, is obtained, allowing for appropriate adjustment of the moving step size in the first optical proximity iteration correction.

[0158] Therefore, on the one hand, the larger optimal step size L2 reduces the number of iterations required for the first optical proximity correction; on the other hand, during the first optical proximity correction, the convergence speed of the edges to be corrected in each iteration is similar, resulting in fewer or no jumps and other defects. This reduces or avoids the additional number of optical proximity corrections required to correct these jumps and other defects. Thus, the overall number of optical proximity correction iterations required to obtain the first corrected pattern can be reduced, thereby effectively improving the efficiency of optical proximity correction.

[0159] Please refer to Figure 14 , Figure 14 This is a flowchart illustrating a method for first optical proximity iteration correction according to an embodiment of the present invention. For step S700, the method of performing the kth step of the first optical proximity iteration correction on the nth detection pattern according to a plurality of optimal moving step lengths L2 corresponding one-to-one with a plurality of nth detection edges to be corrected includes: step S710, moving a plurality of initial k-1th edges to be corrected in the initial k-1th correction pattern by their respective optimal moving step lengths L2 to form an initial kth correction pattern.

[0160] k is a natural number less than or equal to m.

[0161] Wherein, when k=1, the initial (k-1)th corrected layout is the nth probe layout, and the initial (k-1)th edges to be corrected are the nth probe edges to be corrected; when k>1, each initial (k-1)th edge to be corrected corresponds to one of the nth probe edges to be corrected; when k=m, the formed initial mth corrected layout is the first corrected layout.

[0162] Specifically, when k > 1, the initial (k-1)th correction pattern refers to the corresponding initial correction pattern formed in the previous (i.e., the (k-1)th) first optical proximity iteration correction.

[0163] The initial (k-1)th revised version includes: a plurality of initial (k-1)th revised graphics corresponding to a plurality of initial graphics 101.

[0164] The initial (k-1)th edge to be corrected refers to the corresponding edge to be corrected obtained in the previous (i.e., the (k-1)th) first optical proximity iteration correction, and the edge to be corrected is part of the outline of the initial (k-1)th correction pattern.

[0165] Therefore, based on the initial (k-1)th corrected layout, the initial k-th corrected layout is formed by moving several initial (k-1)th edges to be corrected. When moving several initial (k-1)th edges to be corrected, each initial (k-1)th edge to be corrected has its own optimal moving step size L2 (edge ​​moving distance).

[0166] Please continue to refer to this. Figure 14 Regarding step S700, the method of performing m first optical proximity iterations to obtain the first corrected pattern on the nth detection pattern according to several optimal moving step sizes L2 that correspond one-to-one with several nth detection edges to be corrected, further includes step S720, exposing the initial kth corrected pattern to obtain the initial kth exposure corrected pattern.

[0167] Please refer to Figure 15 , Figure 15 This is a flowchart illustrating a method for obtaining an initial k-th exposure-corrected pattern according to an embodiment of the present invention. In step S720, the initial k-th exposure-corrected pattern undergoes exposure processing. The method for obtaining the initial k-th exposure-corrected pattern includes:

[0168] When k is less than m, execute step S721, in the initial k-th correction layout, obtain several initial k-th exposure areas, each initial k-th exposure area corresponds to 1 unit area, and several initial (k-1)-th correction edges after moving their respective optimal moving step size L2 are located within several initial k-th exposure areas; step S722, perform exposure processing on several initial k-th correction areas in the initial k-th correction layout to obtain the exposure layout of several initial k-th correction areas; step S723, modify the initial (k-1)-th exposure correction layout according to the exposure layout of several initial k-th correction areas to form the initial k-th exposure correction layout.

[0169] When k=1, the initial (k-1)th exposure correction pattern is the nth detection exposure pattern.

[0170] In this embodiment, the specific implementation methods of steps S721 to S723 are described in the aforementioned implementation methods and related descriptions of steps S5211 to S5213, and will not be repeated here.

[0171] Please continue to refer to this. Figure 15 Regarding step S720, the method for obtaining the initial k-th exposure-corrected pattern by performing exposure processing on the initial k-th corrected pattern further includes:

[0172] When k equals m, the method for exposing the initial k-th corrected layout to obtain the initial k-th exposure corrected layout includes: step S724, performing global exposure on the first corrected layout to obtain the first exposure corrected layout.

[0173] Therefore, during the m-th iteration of the first optical proximity correction, for each iteration beyond the m-th iteration, a local exposure processing method is adopted. This improves the efficiency of the first optical proximity correction while maintaining the accuracy of defect detection. Simultaneously, the m-th iteration of the first optical proximity correction uses the most accurate global exposure processing method to expose the first corrected pattern, facilitating a more accurate assessment of whether any remaining defects require further correction. This further enhances the accuracy of the optical proximity correction method.

[0174] Please continue to refer to this. Figure 14 Regarding step S700, the method of performing the kth iteration of the first optical proximity iteration correction in m iterations on the nth detection pattern according to several optimal moving step sizes L2 corresponding one-to-one with several nth detection edges to be corrected further includes: step S730, performing defect detection on the initial kth exposure correction pattern; when a defect is detected in the initial kth exposure correction pattern, step S740 is executed, and several initial kth edges to be corrected are obtained in the initial kth correction pattern according to the detected defects.

[0175] When k < m, each initial k-th edge to be corrected corresponds to one of several n-th detected edges to be corrected. When k = m, due to the first exposure correction pattern obtained using global exposure, when a defect is detected in the initial k-th exposure correction pattern, the defect may not correspond to the n-th detected edge to be corrected.

[0176] In this embodiment, the specific implementation of steps S730 to S740 can be found in the implementation of steps S522 to S523 and related descriptions, which will not be repeated here.

[0177] Please continue to refer to this. Figure 14 Regarding step S700, the method of performing the kth time of the first optical proximity iteration correction in m times on the nth detection pattern according to several optimal moving step sizes L2 corresponding one-to-one with several nth detection edges to be corrected further includes: when no defect is detected in the initial kth exposure correction pattern, step S750 is executed to stop the first optical proximity iteration correction.

[0178] In another embodiment, m can also be a preset number of first optical proximity iterations for correction. That is, step S750 is not performed by determining whether a defect is detected in the initial k-th exposure correction pattern. Instead, the first optical proximity iteration is stopped when the preset number of iterations is reached.

[0179] In another embodiment, the optical proximity correction method further includes: when a defect is detected in the first corrected pattern, executing step S800, performing a number of second optical proximity iterations on the first corrected pattern according to a preset minimum moving step size, to obtain a second corrected pattern.

[0180] This further ensures the reliability of the corrected pattern used to form the photomask.

[0181] Specifically, for step S800, the method for the r-th iteration in the several second optical proximity iterations includes:

[0182] Step S810: Move several (r-1)th edges to be corrected in the (r-1)th layout by the preset minimum moving step size to form the rth layout. When r = 1, the (r-1)th layout is the first corrected layout, and several (r-1)th corrected edges are several initial mth edges to be corrected.

[0183] Step S820: Perform exposure processing on the r-th layout to obtain the r-th exposed layout;

[0184] Step S830: Perform defect detection on the r-th exposure pattern;

[0185] When a defect is detected in the r-th exposure pattern, step S840 is executed, and according to the detected defect, a number of r-th edges to be corrected are obtained in the r-th pattern for the (r+1)-th second optical proximity iteration correction.

[0186] When no defect is detected in the r-th exposure pattern, step S850 is executed to stop the second optical proximity iteration correction and use the r-th exposure pattern as the second corrected pattern.

[0187] r is a natural number.

[0188] In other embodiments, the execution of the second optical proximity iteration correction can be stopped according to a preset number of iterations.

[0189] Accordingly, one embodiment of the present invention also provides a method for fabricating a mask based on the above-described optical proximity correction method, comprising: obtaining an initial pattern, the initial pattern comprising a plurality of initial graphics; performing exposure processing on the initial pattern to obtain an initial exposed pattern; detecting defects in the initial exposed pattern; providing a preset window and dividing the outlines of the plurality of initial graphics by the preset window to obtain a plurality of segments; when a defect is detected in the initial exposed pattern, obtaining a plurality of initial edges to be corrected in the plurality of segments according to the defect detected in the initial exposed pattern; performing n iterations of optical proximity correction on the initial pattern, where n is a natural number, and the method for the i-th iteration of optical proximity correction includes: moving a plurality of i-1th edges to be corrected in the (i-1)th detection pattern by a preset minimum moving step to form the i-th detection pattern, where i is a natural number less than or equal to n, and... When i = 1, the (i-1)th detection pattern is the initial pattern, and the (i-1)th detection edge to be corrected is the initial edge to be corrected. The i-th detection pattern undergoes the i-th defect detection step to obtain the i-th detection exposure pattern, and the i-th detection edge to be corrected is obtained from the i-th detection pattern. After the n-th detection optical proximity iteration correction, based on the initial pattern, the initial exposure pattern, the 1st to nth detection patterns, and the 1st to nth detection exposure patterns, several optimal moving step sizes corresponding one-to-one with the n-th detection edge to be corrected are obtained, where the optimal moving step size is greater than or equal to the preset minimum moving step size. Based on the several optimal moving step sizes corresponding one-to-one with the n-th detection edge to be corrected, the n-th detection pattern undergoes m-th first optical proximity iteration corrections to obtain the first corrected pattern, where m is a natural number. A mask is fabricated based on the first corrected pattern.

[0190] It should be noted that the mask fabrication method in this embodiment is complementary to the optical proximity correction method described above in principle. Therefore, the explanations of the terms involved in this embodiment can be found in the relevant descriptions in the above embodiments, and will not be repeated here.

[0191] In this embodiment, a mask is directly made using the first modified pattern.

[0192] In another embodiment, the method of creating a mask based on the first modified pattern includes: creating a mask using a second modified pattern obtained based on the first modified pattern.

[0193] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An optical proximity correction method, characterized in that, include: Obtain an initial layout, which includes several initial graphics; The initial layout is subjected to exposure processing to obtain an initial exposed layout; Detect defects in the initial exposure pattern; A preset window is provided, and the outlines of the initial graphics are divided using the preset window to obtain several segments; When a defect is detected in the initial exposure pattern, several initial edges to be corrected are obtained from the several segments based on the defect detected in the initial exposure pattern. The initial layout is subjected to n iterations of optical proximity correction, where n is a natural number. The method for the i-th iteration of optical proximity correction includes: moving a number of i-1 edges to be corrected in the (i-1)-th detection layout by a preset minimum moving step to form the i-th detection layout, where i is a natural number less than or equal to n. When i=1, the (i-1)-th detection layout is the initial layout, and the number of i-1 edges to be corrected are the number of initial edges to be corrected. The i-th detection layout is subjected to the i-th defect detection step to obtain the i-th detection exposure layout, and the number of i-th edges to be corrected is obtained in the i-th detection layout. After the nth iteration of optical proximity correction, based on the initial layout, initial exposure layout, the first to nth detection layouts, and the first to nth detection exposure layouts, several optimal moving step sizes are obtained, each corresponding to one of the nth detection edges to be corrected. The optimal moving step size is greater than or equal to the preset minimum moving step size. The method for obtaining the optimal moving step size includes: based on the initial layout and initial exposure layout, obtaining the edge placement error EPE0 for each initial edge to be corrected corresponding to the nth detection edges; and based on the first to nth detection layouts and the first to nth detection exposure layouts, obtaining the edge placement error EPE1 to the edge placement error EPE1 corresponding to each nth detection edge to be corrected. n According to the edge placement error EPE0 to the edge placement error EPE corresponding to each nth detected edge to be corrected. n Obtain the optimal movement step size for each nth edge to be probed and corrected. Based on several optimal moving step sizes that correspond one-to-one with several nth detection edges to be corrected, the nth detection pattern is subjected to m first optical proximity iterations to obtain a first corrected pattern, where m is a natural number.

2. The optical proximity correction method as described in claim 1, characterized in that, The method for performing the i-th defect detection step on the i-th detection pattern includes: exposing the i-th detection pattern to obtain the i-th detection exposed pattern; detecting defects in the i-th detection exposed pattern; and obtaining a plurality of i-th detection edges to be corrected in the i-th detection pattern based on the defects detected in the i-th detection exposed pattern, wherein each i-th detection edge to be corrected corresponds to one of the plurality of (i-1)-th detection edges to be corrected.

3. The optical proximity correction method as described in claim 2, characterized in that, The edge placement error EPE1 to the edge placement error EPE n Edge placement error (EPE) in i The method for obtaining the edge placement error (EPE) includes: based on the i-th probe layout and the i-th probe exposure layout, obtaining the edge placement error (EPE) of each i-th probe edge to be corrected corresponding to several n-th probe edges to be corrected. i .

4. The optical proximity correction method as described in claim 3, characterized in that, Based on the edge placement error EPE0 to the edge placement error EPE corresponding to each nth detected edge to be corrected. n Methods for obtaining the optimal movement step size for each nth edge to be probed and corrected include: Provides a preset maximum edge placement error (EPE) for each nth edge to be corrected during detection. SPEC ; Based on the preset maximum edge placement error EPE for each nth edge to be corrected during detection. SPEC The edge placement error EPE0 to the edge placement error EPE corresponding to each nth detected edge to be corrected n Obtain the optimal movement step size L2 for each nth edge to be probed and corrected. The L min It is a preset minimum movement step size, the C i =EPE i - EPE i-1 The W i It is the C mentioned i The weighting coefficients, and .

5. The optical proximity correction method as described in claim 2, characterized in that, The initial layout includes multiple cell regions, and the method for obtaining the i-th probed layout by performing exposure processing on the i-th probed layout includes: In the i-th detection pattern, a number of i-th detection exposure areas are obtained, each i-th detection exposure area corresponds to one unit area, and a number of (i-1)-th detection correction edges after moving the preset minimum moving step are located within the number of i-th detection exposure areas. Exposure processing is performed on the i-th detection areas to obtain the exposure pattern of the i-th detection areas; Based on the exposure patterns of several i-th detection areas to be exposed, the (i-1)-th detection exposure pattern is modified to form the i-th detection exposure pattern. When i=1, the (i-1)-th detection exposure pattern is the initial exposure pattern.

6. The optical proximity correction method as described in claim 1, characterized in that, The methods for performing the k-th iteration of the first optical proximity correction in m iterations include: The initial (k-1)th corrected edge in the initial corrected layout is moved by its corresponding optimal moving step to form the initial k-th corrected layout, where k is a natural number less than or equal to m. When k=1, the initial (k-1)th corrected layout is the nth probe layout, and the initial (k-1)th corrected edge is the nth probe edge. When k>1, each initial (k-1)th corrected edge corresponds to one of the nth probe edges. When k=m, the initial m-th corrected layout is the first corrected layout. The initial k-th corrected layout is exposed to obtain the initial k-th exposure corrected layout; Defect detection is performed on the initial k-th exposure correction pattern; When a defect is detected in the initial k-th exposure correction pattern, several initial k-th edges to be corrected are obtained in the initial k-th correction pattern according to the detected defect, and when k < m, each initial k-th edge to be corrected corresponds to one of several n-th detected edges to be corrected.

7. The optical proximity correction method as described in claim 6, characterized in that, The method for performing the kth iteration of the first optical proximity iteration correction m times further includes stopping the first optical proximity iteration correction when no defect is detected in the initial kth exposure correction pattern.

8. The optical proximity correction method as described in claim 6, characterized in that, The initial layout includes multiple unit areas; When k is less than m, the method for obtaining the initial k-th exposure-corrected layout by performing exposure processing on the initial k-th corrected layout includes: In the initial k-th correction layout, several initial k-th exposure areas are obtained. Each initial k-th exposure area corresponds to one unit area. Furthermore, several initial k-1-th correction edges, after moving their respective optimal moving step sizes, are located within several initial k-th exposure areas. Exposure processing is performed on several initial k-th regions to be corrected in the initial k-th correction pattern to obtain an exposure pattern of several initial k-th regions to be corrected. Based on several initial exposure patterns of the kth region to be corrected, the initial (k-1)th exposure correction pattern is modified to form the initial kth exposure correction pattern. Furthermore, when k=1, the initial (k-1)th exposure correction pattern is the nth detection exposure pattern.

9. The optical proximity correction method as described in claim 8, characterized in that, When k equals m, the method for obtaining the initial k-th exposure correction image by performing exposure processing on the initial k-th correction image includes: performing global exposure on the first correction image to obtain the first exposure correction image.

10. The optical proximity correction method as described in claim 9, characterized in that, Also includes: When a defect is detected in the first corrected layout, the first corrected layout is subjected to several second optical proximity iterations based on a preset minimum moving step size to obtain a second corrected layout.

11. The optical proximity correction method as described in claim 1, characterized in that, The preset minimum movement step size is 0.1 nanometers.

12. The optical proximity correction method as described in claim 1, characterized in that, The n is greater than or equal to 2, and the n is less than or equal to 5.

13. The optical proximity correction method as described in claim 1, characterized in that, The method for obtaining an initial layout includes: providing a target layout; and performing several initial optical proximity iterations on the target layout to obtain an initial layout.

14. A method for manufacturing a photomask, characterized in that, include: Obtain an initial layout, which includes several initial graphics; The initial layout is subjected to exposure processing to obtain an initial exposed layout; Detect defects in the initial exposure pattern; A preset window is provided, and the outlines of the initial graphics are divided using the preset window to obtain several segments; When a defect is detected in the initial exposure pattern, several initial edges to be corrected are obtained from the several segments based on the defect detected in the initial exposure pattern. The initial layout is subjected to n iterations of optical proximity correction, where n is a natural number. The method for the i-th iteration of optical proximity correction includes: moving a number of i-1 edges to be corrected in the (i-1)-th detection layout by a preset minimum moving step to form the i-th detection layout, where i is a natural number less than or equal to n. When i=1, the (i-1)-th detection layout is the initial layout, and the number of i-1 edges to be corrected are the number of initial edges to be corrected. The i-th detection layout is subjected to the i-th defect detection step to obtain the i-th detection exposure layout, and the number of i-th edges to be corrected is obtained in the i-th detection layout. After the nth iteration of optical proximity correction, based on the initial layout, initial exposure layout, the first to nth detection layouts, and the first to nth detection exposure layouts, several optimal moving step sizes are obtained, each corresponding to one of the nth detection edges to be corrected. The optimal moving step size is greater than or equal to the preset minimum moving step size. The method for obtaining the optimal moving step size includes: based on the initial layout and initial exposure layout, obtaining the edge placement error EPE0 for each initial edge to be corrected corresponding to the nth detection edges; and based on the first to nth detection layouts and the first to nth detection exposure layouts, obtaining the edge placement error EPE1 to the edge placement error EPE1 corresponding to each nth detection edge to be corrected. n According to the edge placement error EPE0 to the edge placement error EPE corresponding to each nth detected edge to be corrected. n Obtain the optimal movement step size for each nth edge to be probed and corrected. Based on several optimal moving step sizes that correspond one-to-one with several nth detection edges to be corrected, the nth detection pattern is subjected to m first optical proximity iterations to obtain the first corrected pattern, where m is a natural number. Create a mask based on the first revised version.

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