Optical proximity effect correction method, photomask and readable storage medium

Abstract

This invention relates to an optical proximity effect correction method, a photomask, a readable storage medium, and a computer device. The correction method includes: acquiring a photomask design pattern; selecting an isolated metal pattern that meets a first condition from the photomask design pattern; preprocessing the isolated metal pattern so that the width at both ends of the isolated metal pattern is greater than the width in the middle; and obtaining a photomask fabrication pattern based on the preprocessed isolated metal pattern. Performing additional OPC processing on the isolated metal pattern, ensuring that the width at both ends is greater than the width in the middle, avoids the problem of line shortages at the ends after the isolated metal pattern forms metal lines due to the optical proximity effect. This prevents poor filling and wrapping of the previous layer's filling holes by the metal lines, which leads to fluctuations in key device parameters and results in more stable product performance.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and in particular to an optical proximity effect correction method, a photomask, a readable storage medium, and a computer device. Background Technology

[0002] With the rapid development of Ultra Large Scale Integration (ULSI), integrated circuit manufacturing processes are becoming increasingly complex and sophisticated. In critical layers of technology nodes below 0.13μm, such as TO (active region layer), GT (gate oxide layer), and An (interconnect layer), the critical dimension (CD) is becoming increasingly smaller. The CD of some critical layers is approaching or even smaller than the wavelength of light used in photolithography, which is 248nm. Therefore, during the exposure process in photolithography, due to light interference and diffraction, there is a certain degree of deformation and deviation between the photolithographic pattern obtained on the actual product wafer and the mask pattern. This error in photolithography directly affects circuit performance and production yield.

[0003] In order to eliminate the above-mentioned errors, the OPC (Optical Proximity Correction) method is usually used to make certain corrections to the design drawings.

[0004] However, at the 0.11 / 0.13μm technology node, after using the OPC method to make overall corrections to the design, the nanometer-level linewidth (critical dimension, CD) fluctuations will cause fluctuations in the key parameters of the device, thereby affecting the overall product performance. Summary of the Invention

[0005] Based on this, it is necessary to address the problem that nanometer-level linewidth fluctuations after overall correction of the design using the OPC method in existing technologies can cause fluctuations in key device parameters, thereby affecting the overall product performance. To address this issue, an optical proximity effect correction method, a photomask, a readable storage medium, and a computer device should be provided.

[0006] To achieve the above objectives, the present invention provides an optical proximity effect correction method, comprising:

[0007] Obtain the design pattern of the photolithography mask;

[0008] Select an isolated metal pattern that meets the first condition from the photolithography mask design pattern;

[0009] The isolated metal pattern is preprocessed so that the width at both ends of the isolated metal pattern is greater than the width in the middle.

[0010] The mask pattern is obtained from the preprocessed isolated metal pattern.

[0011] In one embodiment, the step of preprocessing the isolated metal pattern includes adding a first rectangle on both sides of the end of the isolated metal pattern, wherein the length of the first rectangle is 0.4 micrometers and the width is 0.15 micrometers, and the direction of the width is the direction of the two sides.

[0012] In one embodiment, the first condition is that the distance between the isolated metal pattern and any pattern on the same photolithographic layer in the first direction is not less than 1.5 micrometers, and the width of the isolated metal pattern is not greater than 0.85 micrometers and the length is not less than 0.9 micrometers; the first direction is perpendicular to the extension direction of the isolated metal pattern.

[0013] In one embodiment, the method further includes a step of checking and correcting according to regulations, including: if the spacing between the preprocessed isolated metal pattern and any pattern on the same photolithographic layer is less than 0.165 micrometers, then a portion of the first rectangle at the position with the smallest spacing is removed, so that the spacing is greater than 0.165 micrometers.

[0014] The step of obtaining the mask pattern based on the preprocessed isolated metal pattern is to obtain the mask pattern based on the isolated metal pattern after inspection and correction in accordance with regulations.

[0015] In one embodiment, the step of checking and correcting according to regulations includes: if the distance between two non-parallel preprocessed isolated metal patterns is less than 0.165 micrometers, then the second rectangle is removed from the closest corners of the two preprocessed isolated metal patterns. The width of the second rectangle is 0.033 micrometers and the width direction is the width direction of the first rectangle of either of the two preprocessed isolated metal patterns.

[0016] In one embodiment, after the step of checking and correcting according to regulations and before the step of obtaining the mask pattern from the preprocessed isolated metal pattern, the method further includes checking the isolated metal pattern after checking and correcting according to regulations according to design rules, and reporting an error if it does not conform to the design rules.

[0017] In one embodiment, the error message includes: outputting specific graphics and locations that do not conform to the design rules.

[0018] In one embodiment, the step of obtaining the mask pattern from the preprocessed isolated metal pattern further includes:

[0019] After simulating the preprocessed isolated metal pattern, the difference is checked by comparing it with the photolithographic mask design pattern;

[0020] If the difference is greater than 5 nanometers, return to the step of preprocessing the isolated metal pattern and re-perform the optical proximity correction calculation until the difference is no greater than 5 nanometers.

[0021] A photomask, the photomask being fabricated from a photomask pattern obtained by the optical proximity correction method described in any one of the preceding claims.

[0022] A readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described above.

[0023] A computer device includes a memory and a processor, the memory storing a computer program, the processor executing the computer program to implement the steps of any of the methods described above.

[0024] The aforementioned optical proximity correction method performs additional OPC processing on isolated metal patterns, ensuring that the width at both ends of the isolated metal pattern is greater than the width in the middle. This avoids the problem of insufficient line coverage at the ends of isolated metal patterns after forming metal lines due to optical proximity effects, which leads to poor filling and wrapping of the previous layer's filling holes and fluctuations in key device parameters, resulting in more stable product performance. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram of an exemplary OPC processing flow;

[0027] Figure 2 This is a flowchart illustrating an optical proximity effect correction method in one embodiment;

[0028] Figure 3 This is a top view of the preprocessed isolated metal pattern obtained after step S106 in Example 1.

[0029] Figure 4 This is a top view of the preprocessed isolated metal pattern obtained after step S106 in Example 2.

[0030] Figure 5 This is a top view of the preprocessed isolated metal graphic obtained after step S106 in Example 3.

[0031] Figure 6 This is a flowchart illustrating an optical proximity effect correction method in one embodiment of this application. Detailed Implementation

[0032] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0034] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, parts, regions, layers, doping types, and / or portions, these elements, parts, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, part, region, layer, doping type, or portion from another element, part, region, layer, doping type, or portion. Therefore, without departing from the teachings of this invention, the first element, component, region, layer, doping type, or portion discussed below may be represented as a second element, component, region, layer, or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.

[0035] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0036] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, in this specification, the term “and / or” includes any and all combinations of the associated listed items.

[0037] Embodiments of the invention are described herein with reference to cross-sectional views illustrating ideal embodiments (and intermediate structures) of the invention, thus allowing for variations in the illustrated shape due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the invention should not be limited to the specific shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing techniques. For instance, implantation regions shown as rectangular typically have rounded or curved features at their edges and / or implantation concentration gradients, rather than a binary change from implantation regions to non-implantation regions. Similarly, the buried regions formed by implantation can result in some implantation in the region between the buried region and the surface traversed during implantation. Therefore, the regions shown in the figures are substantially schematic, and their shapes do not represent the actual shapes of regions of the device and do not limit the scope of the invention.

[0038] At critical levels of technology nodes at 0.13μm and below, changes in the morphology of metal cladding can cause fluctuations in key parameters of semiconductor devices, thereby affecting overall product performance.

[0039] See Figure 1An exemplary OPC processing flow includes: (1) Process condition fixing: obtaining design rules and lithography process conditions, including optical parameters of the exposure optical path, material parameters of the photoresist, and chemical parameters of the etching process. (2) OPC modeling data collection: forming a pre-designed test pattern on a dummy wafer according to the lithography process conditions, collecting the test data corresponding to the lithography process conditions as OPC model data. (3) OPC model establishment: inputting the collected test data and process conditions into the OPC modeling tool, setting up software simulation, and generating the OPC model. (4) OPC program setting: developing a program (recipe) to run the OPC model. (5) Design pattern OPC calculation: performing OPC calculation on the design pattern to obtain a corrected pattern. (6) OPC accuracy verification: generating a contour of the corrected pattern through software simulation and checking the difference with the design pattern to confirm whether it meets the specification requirements. When the difference exceeds 5nm, the OPC calculation is repeated until it is qualified. (7) Photolithography plate making: Photolithography plate making is carried out according to the modified graphic that meets the specifications for the difference.

[0040] The aforementioned OPC strategy only corrects the overall optical proximity effect of the metal layer, without considering the influence of the special optical proximity effect of isolated patterns. Compared with other patterns in the same metal layer, isolated patterns are more severely shortened due to the optical proximity effect, resulting in poorer coverage of holes in the previous layer. This, in turn, affects the filling and wrapping effect of the formed metal lines on the holes in the previous layer, leading to a deterioration in the morphology of the metal hole and making the product more prone to failure.

[0041] See Figure 2 This is a flowchart illustrating an optical proximity effect correction method in one embodiment.

[0042] like Figure 2 As shown, in one embodiment, an optical proximity effect correction method is provided, comprising:

[0043] S102, Obtain the photolithography mask design pattern.

[0044] After designing the integrated circuit according to the actual needs, design patterns for each layer that match the needs are obtained. Then, the metal patterns corresponding to each metal layer are selected as the photolithography mask design patterns.

[0045] S104, Select an isolated metal pattern that meets the first condition from the photolithography mask design pattern.

[0046] The metal pattern in the photolithography mask design pattern is composed of multiple patterns. From the photolithography mask design pattern obtained in step S102, the patterns that meet the first condition are selected as isolated metal patterns, and the patterns that do not meet the first condition are selected as non-isolated metal patterns.

[0047] S106, preprocess the isolated metal graphic to make the width at both ends of the isolated metal graphic greater than the width in the middle.

[0048] After obtaining isolated metal patterns, the two ends of each isolated metal pattern are preprocessed to make the width at both ends of the isolated metal pattern greater than the width in the middle, resulting in a new isolated metal pattern that is narrow in the middle and wide at both ends along the extension direction of each isolated metal pattern, which is used as the first pattern.

[0049] S108, obtain the mask pattern based on the preprocessed isolated metal pattern.

[0050] The isolated metal pattern in the photolithography mask design is replaced with the pre-processed isolated metal pattern to obtain the mask pattern consisting of the pre-processed isolated metal pattern and the non-isolated metal pattern, that is, the mask pattern corresponding to each metal layer.

[0051] In one embodiment, the first condition is that the spacing between the isolated metal pattern and any pattern on the same photolithographic layer in the first direction is not less than 1.5 micrometers, and the width of the isolated metal pattern is not greater than 0.85 micrometers and the length is not less than 0.9 micrometers; the first direction is perpendicular to the extension direction of the isolated metal pattern, that is, the first direction is parallel to the width direction of the isolated metal pattern.

[0052] Specifically, any metal pattern in the photolithographic mask design is selected. If the width W1 of a pattern A in this metal pattern is ≤0.85μm, the length L1 is ≥0.9μm, and the distance D1 from other patterns in the first direction is ≥1.5μm, then pattern A is an isolated metal pattern. The first direction is perpendicular to the extension direction of pattern A, i.e., parallel to the width direction of pattern A. For isolated metal patterns in the photolithographic mask design that are affected by the optical proximity effect, resulting in severe shortening at the ends of the metal lines after formation, leading to poor filling and encapsulation of the previous layer's vias and causing product failure, these isolated metal patterns can be screened out using the first condition. Then, the ends of the screened isolated metal patterns are thickened to make the width at both ends greater than the width in the middle, reducing the problem of shorting at the ends of the metal lines after formation. This improves the morphology of the vias at the ends of the metal patterns after forming the metal lines, thereby enhancing product performance.

[0053] See Figure 3This is a top view of the preprocessed isolated metal pattern obtained after step S106 in Example 1.

[0054] like Figure 3 As shown, in one embodiment, step S106 includes: adding a first rectangle on both sides of the end of the isolated metal pattern, the first rectangle having a length of 0.4 micrometers and a width of 0.15 micrometers, wherein the width direction of the first rectangle is the direction of both sides of the end of the isolated metal pattern.

[0055] Specifically, the isolated metal graphic 10 includes a first end 102, a second end 104, and an intermediate portion located between the first end 102 and the second end 104; the isolated metal graphic 20 includes a first end 202, a second end 204, and an intermediate portion located between the first end 202 and the second end 204. A first rectangle 1020 and a first rectangle 1022 are added to both sides of the first end 102, and a first rectangle 1040 and a first rectangle 1042 are added to both sides of the second end 104; a first rectangle 2020 and a first rectangle 2022 are added to both sides of the first end 202, and a first rectangle 2040 and a first rectangle 2042 are added to both sides of the second end 204; wherein, the first rectangles 1020 and 1022, and the first rectangles 1040 and 1042 are all related to the first end 102. 2. The line connecting the first end 202 and the second end 104 is symmetrical; the first rectangles 2020 and 2022, and the first rectangles 2040 and 2042 are all symmetrical about the line connecting the first end 202 and the second end 204; and the lengths L2 and L3 of the first rectangles 1020, 1022, 1040, and 1042 are all 0.4 μm, and the widths W2 are all 0.15 μm. By adding the first rectangles, the ends of the metal lines formed by the isolated metal patterns 10 and 20 are widened, resulting in stronger filling and wrapping capabilities for the filling holes formed below the metal lines, and more stable product performance.

[0056] See Figure 4 This is a top view of the preprocessed isolated metal pattern obtained after step S106 in Example 2.

[0057] like Figure 4 As shown, in one embodiment, step S106 further includes:

[0058] A third rectangle is added to each end of the isolated metal graphic, extending in the same direction. The width of the third rectangle is 0.15 micrometers, and its length is the sum of the width of the isolated metal graphic and 0.3 micrometers. The length of the third rectangle extends to both sides of the ends of the isolated metal graphic, and its width extends in the same direction as the ends of the isolated metal graphic.

[0059] In this embodiment, third rectangles 1024 and 1044 are added to the extension directions at both ends of the isolated metal graphic 10, respectively. The width of the third rectangles 1024 and 1044 is L4. The first rectangle 1020, the first rectangle 1022, the third rectangle 1024 and the first end 102, as well as the first rectangle 1040, the first rectangle 1042, the third rectangle 1044 and the second end 104 are all rectangular structures. Third rectangles 2024 and 2044 are added to the extension direction of the isolated metal graphic 20, respectively. The length of the third rectangles 2024 and 2044 is L5. The first rectangle 2020, the first rectangle 2022, the third rectangle 2024 and the first end 202, as well as the first rectangle 2040, the first rectangle 2042, the third rectangle 2044 and the second end 204 are all rectangular structures. Compared to adding only the first rectangle, adding the third rectangle increases the length of the metal lines formed by the isolated metal pattern, further improving the ability of the metal lines formed by the isolated metal pattern to fill and wrap the filling holes formed below the metal lines, making the product performance (electrical parameters of the device) more stable.

[0060] In one embodiment, L4 and L5 are equal, for example, both being 0.15 micrometers. In practical applications, the values ​​of L4 and L5 can be selected according to actual needs. In other embodiments, L4 and L5 can be unequal values.

[0061] In one embodiment, step S106 is followed by a step of checking and correcting according to regulations, including: if the spacing between the preprocessed isolated metal pattern and any pattern on the same photolithographic layer is less than 0.165 micrometers, then a portion of the preprocessed pattern added at the position with the smallest spacing is removed, thereby making the spacing greater than 0.165 micrometers. Accordingly, step S108 is to obtain the mask pattern based on the isolated metal pattern after checking and correcting according to regulations.

[0062] See Figure 5 This is a top view of the preprocessed isolated metal graphic obtained after step S106 in Example 3.

[0063] like Figure 5As shown, if the distance D2 between two pre-processed isolated metal patterns 10 and 20 that are not parallel is less than 0.165 μm, then the second rectangle is removed from the closest corners of the two pre-processed isolated metal patterns 10 and 20. That is, the corner 1041 of the third rectangle 1044 removes the second rectangle 1046 to obtain the first added part 1043; the corner 2041 of the third rectangle 2044 removes the second rectangle 2046 to obtain the second added part 2043. The length of the first side M1 of the second rectangle 1046 is X1, and the length of the second side N1 is Y1; the length of the first side M2 of the second rectangle 2046 is X2, and the length of the second side N2 is Y2. The first side M1 is parallel to the first side M2, and the second side N1 is parallel to the first side N2. Among them, X1 = X2 = 0.033 μm, Y1 = Y2 < W2, or Y1 = Y2 = 0.033 μm, X1 = X2 < L2. When D2 < 0.165 μm, by removing the second rectangle, it is possible to avoid the problem of metal bridging between two metal lines after the pre-processed isolated metal patterns 10 and 20 form metal lines, that is, the problem of abnormal metal interconnection between two separated metal lines, thereby achieving the purpose of improving product performance. In practical applications, different distances D2, different X1, X2, Y1, and Y2 can be selected according to design requirements.

[0064] In another embodiment, the lengths of the first side M1 of the second rectangle 1046 and the first side M2 of the second rectangle 2046 are equal, and the lengths of the second side N1 of the second rectangle 1046 and the second side N2 of the second rectangle 2046 are not equal; or the lengths of the first side M1 of the second rectangle 1046 and the first side M2 of the second rectangle 2046 are not equal, and the lengths of the second side N1 of the second rectangle 1046 and the second side N2 of the second rectangle 2046 are equal.

[0065] In one of the embodiments, after the step of checking and correcting according to regulations and before step S108, there is also a step of checking the isolated metal pattern that has been checked and corrected according to design rules, and reporting an error if it does not meet the design rules.

[0066] In one of the embodiments, the error reporting includes: outputting the specific pattern and position that do not meet the design rules.

[0067] Specifically, the isolated metal pattern after correction and inspection is checked according to the design rules. If it does not conform to the design rules, an error is reported as follows: First, check whether the width of the preprocessed isolated metal pattern B is less than or equal to 0.15μm. If the width is greater than 0.15μm, output the shape and position of the isolated metal pattern B. Second, check whether the space between the output isolated metal pattern B and the added dummy is greater than 0.095μm. If the space is less than or equal to 0.095μm, output the shape and position of the isolated metal pattern B. Third, check whether the space between the isolated metal pattern B and the pattern directly opposite it in the same photolithography layer (the pattern that intersects in the same photolithography layer) is greater than 0.165μm. If the space is less than or equal to 0.165μm, output the shape and position of the isolated metal pattern B. The fourth step is to check whether the space between the isolated metal pattern B and the pattern on the side of the same photolithographic layer (patterns with the same extension direction in the same photolithographic layer) is greater than 0.15μm. If the space is less than or equal to 0.15μm, the shape and position of the isolated metal pattern B are output. By performing a design rule check on the corrected isolated metal pattern, patterns that do not conform to the design rules are output, eliminating the risk of the corrected pattern being non-compliant.

[0068] The specific code executed using the mentro OPC tool is as follows:

[0069] M2_XOR_BOX=SIZE(M2_CLN_OUTSIDE XOR M2_CLN_F_850)BY 0.075UNDEROVER

[0070] M2_XOR_BOX{DFM RDB M2_XOR_BOX”. / OPC / AC092end_D1ULP_L153AxA8_20200605.rdb”NOEMPTY ALL CELLS}

[0071] M2_XOR_BOX_DUM=(SIZE(M2_INPUT XOR M2_RB_MER_1)BY 0.095UNDEROVER)XORM2_EXCLUDED_1

[0072] M2_XOR_BOX_DUM{DFM RDB M2_XOR_BOX_DUM”. / OPC / AC092 end_D1ULP_L153AxA8_20200605.rdb”NOEMPTY ALL CELLS}

[0073] M2_MIN_SPACE_PROJ=EXT M2_RB_MER<0.165PROJECTING>=0.000

[0074] M2_MIN_SPACE_PROJ{DFM RDB M2_MIN_SPACE_PROJ”. / OPC / AC092 end_D1ULP_L153AxA8_20200605.rdb”NOEMPTY ALL CELLS}

[0075] M2_MIN_SPACE_NOPROJ=EXT M2_RB_MER<0.15NOT PROJECTING

[0076] M2_MIN_SPACE_NOPROJ{DFM RDB M2_MIN_SPACE_NOPROJ”. / OPC / AC092 end_D1ULP_L153AxA8_20200605.rdb”NOEMPTY ALL CELLS}

[0077] M2_MIN_WIDTH=INT M2_RB_MER<0.2NOT REGION

[0078] M2_MIN_WIDTH{DFM RDB M2_MIN_WIDTH”. / OPC / AC092 end_D1ULP_L153AxA8_20200605.rdb”NOEMPTY ALL CELLS}

[0079] In one embodiment, before step S108, the method further includes: simulating the preprocessed isolated metal pattern and comparing it with the photolithographic mask design pattern to perform a difference check; if the difference is greater than 5 nanometers, then returning to step S106 to perform the optical proximity effect correction calculation again until the difference check is no greater than 5 nanometers.

[0080] Specifically, the preprocessed isolated metal pattern and non-isolated metal pattern are simulated by software to obtain the simulated pattern. The simulated pattern and the photolithographic mask design pattern are compared to check for differences and confirm whether the obtained simulated pattern can meet the specification requirements. If the difference between the simulated pattern and the photolithographic mask design pattern is greater than 5nm, the process returns to step S106 and the optical proximity effect correction calculation is performed again until the difference is no greater than 5nm. The preprocessed isolated metal pattern and non-isolated metal pattern obtained at this time constitute the mask pattern.

[0081] In one embodiment, step S108 is followed by a step of creating a photomask based on the mask pattern.

[0082] In one embodiment, the optical proximity effect correction method described above is applied to technology nodes of 0.153 μm and below.

[0083] Figure 6 This is a schematic flowchart of an optical proximity effect correction method according to an embodiment of this application. The following references... Figure 6 The optical proximity effect correction method in this application is described as follows: (1) Fixed process conditions: The design rules and photolithography process conditions are obtained. The photolithography process conditions include the optical parameters of the exposure optical path, the material parameters of the photoresist, and the chemical parameters of the etching process. (2) OPC modeling data collection: According to the photolithography process conditions, a pre-designed test pattern is formed on a dummy wafer, and the test data corresponding to the photolithography process conditions is collected as OPC model data. (3) OPC model establishment: The collected test data and process conditions are input into the OPC modeling tool, the software simulation is set, and the OPC model is generated. (4) OPC program setting: The program (recipe) for running the OPC model is developed. (5) Selection of isolated metal patterns in metal layers: That is, the isolated metal patterns in each metal layer are selected. Specifically, the conditions of the metal patterns that need to be corrected (width≤0.85μm, space≥1.5μm, length≥0.9μm, etc.) are set in the OPC program. After execution, the pattern that needs to be corrected, i.e., the isolated metal pattern, is selected. (6) Perform special OPC operations on the graphics: Preprocess the isolated metal graphics. Specifically, the code for (5) and (6) when executed using the mentro OPC tool is as follows:

[0084] M2_CLN_850=CONVEX ENGE M2_CLN_OUTSIDE ANGLE1==90LENGTH1>0.9ANGLE2==90LENGTH2>0.9WITH LENGTH>0<=0.850

[0085] M2_CLN_BOX_1_850=EXPAND EDGE M2_CLN_850inside by 0.4EXTEND BY 0.15

[0086] M2_CLN_BOX_850=NOT M2_CLN_BOX_1_850M2_CLN_OUTSIDE

[0087] M2_CLN_SPACE_D_850=EXTERNAL[M2_CLN_OUTSIDE]<=1.5OPPOSITE EXTENDED0.15

[0088] M2_BOX_D_850=M2_CLN_BOX_850NOT WITH EDGE M2_CLN_SPACE_D_850

[0089] M2_CLN_F_850_1=M2_CLN_BOX_D_850OR M2_CLN_OUTSIDE

[0090] M2_CLN_F_850_2=EXTERNAL[M2_CLN_F_850_1]<0.165

[0091] M2_CLN_F_850_3=EXPAND EDGE M2_CLN_F_850_2inside by 0.033

[0092] M2_CLN_F_850_4=EXTENTS M2_CLN_F_850_3

[0093] M2_CLN_F_850=M2_CLN_F_850_1NOT M2_CLN_F_850_4

[0094] (7) OPC accuracy verification: After merging the pre-processed isolated metal patterns and non-isolated metal patterns into a corrected pattern, the contour generated by the corrected pattern is compared with the design pattern through software simulation to check whether it meets the specification requirements. When the difference exceeds 5nm, the OPC calculation is repeated until it is qualified. (8) Photolithography pattern making: The qualified pattern data after OPC processing is sent to the mask shop to make the photolithography pattern.

[0095] This application provides a photomask, which is made from a photomask pattern obtained by the optical proximity effect correction method described in any one of the above claims.

[0096] This application also provides a readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any of the methods described above.

[0097] This application also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of any of the methods described above.

[0098] The aforementioned optical proximity effect correction method performs additional OPC processing on isolated metal patterns, making the width at both ends of the isolated metal pattern greater than the width in the middle. This avoids the problem of line shortage at the ends after the isolated metal pattern forms metal lines due to the optical proximity effect, resulting in poor filling and wrapping effect of the metal lines on the previous layer of filling holes, which leads to fluctuations in key device parameters.

[0099] It should be understood that, although Figure 2 The steps in the flowchart are shown sequentially as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order in which these steps are executed, and they can be performed in other orders. Figure 2 At least some of the steps in the process may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but may be executed at different times. The execution order of these steps or stages is not necessarily sequential, but may be executed in turn or alternately with other steps or at least some of the steps or stages in other steps.

[0100] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0101] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features of the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0102] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for correcting the optical proximity effect, characterized in that, include: Obtain the design pattern of the photolithography mask; Select an isolated metal pattern that meets the first condition from the photolithography mask design pattern; The first condition is that the distance between the isolated metal pattern and any pattern on the same photolithographic layer in the first direction is not less than 1.5 micrometers, and the width of the isolated metal pattern is not greater than 0.85 micrometers and the length is not less than 0.9 micrometers; the first direction is perpendicular to the extension direction of the isolated metal pattern. The isolated metal pattern is preprocessed so that the width at both ends of the isolated metal pattern is greater than the width in the middle. The mask pattern is obtained from the preprocessed isolated metal pattern; The step of preprocessing the isolated metal pattern includes adding a first rectangle on both sides of the end of the isolated metal pattern. The first rectangle has a length of 0.4 micrometers and a width of 0.15 micrometers, wherein the width is in the direction of the two sides.

2. The optical proximity effect correction method according to claim 1, characterized in that, The step of preprocessing the isolated metal pattern further includes: adding a third rectangle in the extension direction at both ends of the isolated metal pattern, wherein the width of the third rectangle is 0.15 micrometers and the length is the sum of the width of the isolated metal pattern and the length of the third rectangle is 0.3 micrometers; wherein the length direction of the third rectangle is the direction of both sides of the end of the isolated metal pattern, and the width direction is the extension direction of the end of the isolated metal pattern.

3. The optical proximity effect correction method according to claim 1, characterized in that, It also includes a step of checking and correcting according to regulations, including: if the distance between the pre-processed isolated metal pattern and any pattern on the same photolithography layer is less than 0.165 micrometers, then a portion of the first rectangle at the position with the smallest distance is removed, so that the distance is greater than 0.165 micrometers; The step of obtaining the mask pattern based on the preprocessed isolated metal pattern is to obtain the mask pattern based on the isolated metal pattern after inspection and correction in accordance with regulations.

4. The optical proximity effect correction method according to claim 3, characterized in that, The procedure for inspection and correction includes: if the distance between two non-parallel pre-processed isolated metal patterns is less than 0.165 micrometers, then the second rectangle is removed from the closest corners of the two pre-processed isolated metal patterns. The width of the second rectangle is 0.033 micrometers and the width direction is the width direction of the first rectangle of either of the two pre-processed isolated metal patterns.

5. The optical proximity effect correction method according to claim 4, characterized in that, After the step of checking and correcting according to regulations, and before the step of obtaining the mask plate-making pattern from the preprocessed isolated metal pattern, the method further includes checking the isolated metal pattern after checking and correcting according to regulations according to design rules, and reporting an error if it does not conform to the design rules.

6. The optical proximity effect correction method according to claim 5, characterized in that, The error message includes: outputting specific graphics and locations that do not conform to the design rules.

7. The optical proximity effect correction method according to claim 1, characterized in that, The step of obtaining the mask pattern based on the preprocessed isolated metal pattern also includes the following: After simulating the preprocessed isolated metal pattern, the difference is checked by comparing it with the photolithographic mask design pattern; If the difference is greater than 5 nanometers, return to the step of preprocessing the isolated metal pattern and re-perform the optical proximity correction calculation until the difference is no greater than 5 nanometers.

8. A photomask, characterized in that, The mask is made from the mask pattern obtained by the optical proximity effect correction method according to any one of claims 1-7.

9. A readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

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