Curve-type mask-oriented optical proximity correction method and related equipment

Abstract

The invention provides an optical proximity correction method for a curve type mask and related equipment, and the method comprises the steps: obtaining an original mask pattern from a target layout file, initializing the original mask pattern, extracting the initial end point of each curve, and generating an end point set; simulating the original mask pattern to obtain a gradient map, and obtaining an endpoint set of the sub-resolution auxiliary pattern based on the gradient map; merging the end point sets of the sub-resolution auxiliary graph to obtain a merged end point set, generating a curve mask through a heuristic algorithm, and simulating the curve mask to obtain a mask plate; performing optical proximity correction on the vertex position of the mask through a gradient-based optimization method to obtain an optical proximity correction result of the mask; and the accuracy of optical proximity correction is improved.

Description

Technical Field

[0001] This invention relates to the field of electronic design automation technology, and in particular to an optical proximity correction method and related equipment for curved masks. Background Technology

[0002] Optical Proximity Correction (OPC) is a pattern optimization technique used in semiconductor manufacturing. It aims to compensate for proximity effects during photolithography by adjusting the design pattern. Due to limitations in photolithography resolution, patterns often become distorted during printing, especially when patterns are close together on the mask. OPC corrects these distortions by adding auxiliary structures (such as compensation lines or shape modifications) to the design, ensuring the correct pattern on the final chip.

[0003] The advent of multi-beam photomask writers has made the fabrication of curve masks possible. Multi-beam systems employ a pixel-based exposure method, using thousands of independently controlled beams, enabling the direct writing of complex curve geometries without increasing writing time. In the curve OPC process, complex curves can be represented as interconnected curves, each defined by a set of vertices. By adjusting the positions of these vertices, the lithographic errors of the curve OPC can be iteratively optimized.

[0004] The current mainstream method for implementing curve OPC is to gradually move vertices using heuristic algorithms and locally reconstruct the curve. However, this curve OPC relies on a trial-and-error process of vertex movement and lacks systematic guidance or theoretical foundation to explain the adjustments, thus limiting performance optimization. Summary of the Invention

[0005] This invention provides an optical proximity correction method and related equipment for curved masks, with the aim of improving the accuracy of optical proximity correction.

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

[0007] Step 1: Obtain the original mask pattern from the target layout file. The original mask pattern includes multiple curve segments. After initializing the original mask pattern, extract the initial endpoints of each curve segment to generate an endpoint set.

[0008] Step 2: Simulate the original mask pattern to obtain the gradient map, and obtain the endpoint set of the sub-resolution auxiliary graphics based on the gradient map;

[0009] Step 3: Merge the endpoint set of the sub-resolution auxiliary graphics with the endpoint set to obtain the merged endpoint set;

[0010] Step 4: Generate a curve mask from the merged endpoint set using a heuristic algorithm, and simulate the curve mask to obtain the mask version;

[0011] Step 5: Perform optical proximity correction on the vertex positions of the mask using a gradient-based optimization method to obtain the optical proximity correction result of the mask.

[0012] Furthermore, step 1 includes:

[0013] After obtaining the coordinate information of each element in the target layout file using open-source tools, all elements are curve-converted to obtain the original mask pattern. The original mask image includes multiple curve segments.

[0014] The original mask pattern is initialized to obtain the initialized mask pattern;

[0015] The elements in the initialized mask pattern are segmented to obtain multiple curves, and the segmentation points are used as the initial endpoints of each curve to generate an endpoint set.

[0016] Furthermore, curve-simplify all elements to obtain the original mask pattern, including:

[0017] Replace the corner of each element with a quarter-circle arc to obtain the original mask pattern.

[0018] Furthermore, step 2 includes:

[0019] Photolithography simulation of the original mask pattern is performed to obtain the gradient map;

[0020] In the gradient map, all pixels are traversed, and pixels with gradient values ​​higher than their neighboring pixels are identified as maxima, while pixels with gradient values ​​lower than their neighboring pixels are identified as minima.

[0021] Local extrema are found in the gradient map based on the maxima and minima, and all local extrema are used as initial sub-resolution auxiliary graph seeds.

[0022] Calculate the Euclidean distance between all initial sub-resolution auxiliary graphic seeds, and filter all initial sub-resolution auxiliary graphic seeds based on the distance between two initial sub-resolution auxiliary graphic seeds to obtain sub-resolution auxiliary graphic seeds;

[0023] The endpoint set of the sub-resolution auxiliary image is generated by expanding the sub-resolution auxiliary image seed.

[0024] Furthermore, based on the sub-resolution auxiliary image seed, an endpoint set of sub-resolution auxiliary graphics is generated, including:

[0025] Starting from each sub-resolution auxiliary graphic seed, and extending it to 12 target directions with a preset length, sub-resolution auxiliary graphics are obtained, and the extension endpoint is taken as the endpoint set of the sub-resolution auxiliary graphics.

[0026] Furthermore, a curve mask is generated from the merged endpoint set using a heuristic algorithm, including:

[0027] Multiple initial Bézier curves are constructed using the merged endpoint set, and the endpoint of each initial Bézier curve is used as the starting point of the next initial Bézier curve.

[0028] The first and second control points of each initial Bézier curve segment are generated using a heuristic algorithm.

[0029] Generate Bézier curves based on the start point, end point, first control point, and second control point of each initial Bézier curve;

[0030] Generate a curve mask based on all Bézier curves.

[0031] Furthermore, the control points for each initial Bézier curve segment are generated using a heuristic algorithm, including:

[0032] Construct an angle bisector using the endpoints of three adjacent initial Bézier curves;

[0033] Based on the concavity and convexity of the curve, rotate the angle bisector by 90° to obtain the rotated angle bisector;

[0034] The first control point is determined by moving along the positive direction of the rotated angle bisector according to a preset ratio, based on the distance between the endpoints of the first two adjacent initial Bézier curves.

[0035] The second control point is determined by moving along the opposite direction of the rotated angle bisector according to a preset ratio, based on the distance between the endpoints of the last two adjacent initial Bézier curves.

[0036] Furthermore, the expression for optical proximity correction of the vertex positions of the mask using a gradient-based optimization method is as follows:

[0037] ;

[0038] in, Represents the total loss function. Represents the endpoint set, Indicates a mask. This represents the gradient of the loss function with respect to the mask during the photolithography simulation stage. This represents the gradient of the mask in the x-direction at the endpoint. This represents the gradient of the mask in the y-direction at the endpoint.

[0039] The present invention also provides an optical proximity correction device for curved masks, comprising:

[0040] The extraction module is used to obtain the original mask pattern from the target layout file. The original mask pattern includes multiple curve segments. After initializing the original mask pattern, the initial endpoints of each curve segment are extracted to generate an endpoint set.

[0041] The simulation module is used to simulate the original mask pattern, obtain the gradient map, and obtain the endpoint set of the sub-resolution auxiliary graphics based on the gradient map.

[0042] The merging module is used to merge the endpoint sets of sub-resolution auxiliary graphics to obtain a merged endpoint set.

[0043] The generation module is used to generate a curve mask from the merged endpoint set using a heuristic algorithm, and to simulate the curve mask to obtain the mask version.

[0044] The correction module is used to perform optical proximity correction on the vertex positions of the mask using a gradient-based optimization method, so as to obtain the optical proximity correction result of the mask.

[0045] The present invention also provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement an optical proximity correction method for curved masks.

[0046] The above-described solution of the present invention has the following beneficial effects:

[0047] This invention obtains the original mask pattern from the target layout file. The original mask pattern includes multiple curve segments. After initializing the original mask pattern, the initial endpoints of each curve segment are extracted to generate an endpoint set. The original mask pattern is simulated to obtain a gradient map, and the endpoint set of sub-resolution auxiliary graphics is obtained based on the gradient map. The endpoint set of the sub-resolution auxiliary graphics is merged with the endpoint set to obtain a merged endpoint set. A curve mask is generated using a heuristic algorithm, and the curve mask is simulated to obtain a mask plate. Optical proximity correction is performed on the vertex positions of the mask plate using a gradient-based optimization method to obtain the optical proximity correction result of the mask plate. Compared with the prior art, this invention converts the traditional Manhattan-shaped mask into a curve mask through initialization, extracts the initial endpoints, simulates the original mask pattern to obtain a gradient map, and obtains the endpoint set of sub-resolution auxiliary graphics based on the gradient map. The endpoint set of the sub-resolution auxiliary graphics is merged with the endpoint set to participate in optimization. Finally, the optical proximity correction of the vertex positions of the mask plate is performed using a gradient-based optimization method, which improves the accuracy of optical proximity correction.

[0048] Other beneficial effects of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0049] Figure 1 This is a flowchart illustrating an embodiment of the present invention;

[0050] Figure 2 This is a schematic diagram of the optical proximity correction device in an embodiment of the present invention;

[0051] Figure 3 This is a schematic diagram of the structure of the terminal device in an embodiment of the present invention. Detailed Implementation

[0052] To make the technical problems, solutions, and advantages of this invention clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0053] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0054] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0056] This invention addresses existing problems by providing an optical proximity correction method and related equipment for curved masks.

[0057] like Figure 1As shown, an embodiment of the present invention provides an optical proximity correction method for curved masks, comprising:

[0058] Step 1: Obtain the original mask pattern from the target layout file. The original mask pattern includes multiple curve segments. After initializing the original mask pattern, extract the initial endpoints of each curve segment to generate an endpoint set.

[0059] Step 2: Simulate the original mask pattern to obtain the gradient map, and obtain the endpoint set of the sub-resolution auxiliary graphics based on the gradient map;

[0060] Step 3: Merge the endpoint set of the sub-resolution auxiliary graphics with the endpoint set to obtain the merged endpoint set;

[0061] Step 4: Generate a curve mask from the merged endpoint set using a heuristic algorithm, and simulate the curve mask to obtain the mask version;

[0062] Step 5: Perform optical proximity correction on the vertex positions of the mask using a gradient-based optimization method to obtain the optical proximity correction result of the mask.

[0063] Specifically, step 1 includes:

[0064] After obtaining the coordinate information of each element in the target layout file using open-source tools, all elements are curve-converted to obtain the original mask pattern. The original mask image includes multiple curve segments.

[0065] The original mask pattern is initialized to obtain the initialized mask pattern;

[0066] The elements in the initialized mask pattern are segmented to obtain multiple curves, and the segmentation points are used as the initial endpoints of each curve to generate an endpoint set.

[0067] In this embodiment of the invention, the target layout file is a circuit layout file (GDS, Graphic Data System File), which contains the position information of elements such as rectangles, paths, and polygons in the mask. This information is stored in the form of vertex coordinates.

[0068] This invention embodiment utilizes the db library in the open-source tool klayout to directly obtain coordinate information from a file. Since there is currently no open-source curve mask data, the layout shapes are mostly Manhattan shapes, i.e., right-angled polygons. Therefore, this invention embodiment requires first curving all elements.

[0069] Replace the corner of each element with a quarter-circle arc to obtain the original mask pattern.

[0070] In this embodiment of the invention, each element in the initialized mask pattern is segmented to obtain multiple curves, and the segmentation points are used as the initial endpoints of each curve. Specifically:

[0071] Assume the radius of the arc is The initial length of each curve is 1, and the radius is subtracted from the beginning and end of each side of the polygon. The remaining line segments are evenly divided according to a length of 1, and the cut-off points are used as the endpoints of each curve to obtain the initial endpoints. These initial endpoints will represent the corresponding curves for optimization.

[0072] Since sub-resolution assist feature (SRAF) is a key technology for improving lithography accuracy in optical proximity correction, SRAF is an auxiliary pattern added to the lithography mask. Its size is lower than the resolution limit of the lithography system, so it does not directly image on the wafer; however, it significantly improves the imaging quality of the main feature by changing the diffraction and interference behavior of light.

[0073] Specifically, step 2 includes:

[0074] Photolithography simulation of the original mask pattern is performed to obtain the gradient map;

[0075] In the gradient map, all pixels are traversed, and pixels with gradient values ​​higher than their neighboring pixels are identified as maxima, while pixels with gradient values ​​lower than their neighboring pixels are identified as minima.

[0076] Local extrema are found in the gradient map based on the maxima and minima, and all local extrema are used as initial sub-resolution auxiliary graph seeds.

[0077] Calculate the Euclidean distance between all initial sub-resolution auxiliary graphic seeds, and filter all initial sub-resolution auxiliary graphic seeds based on the distance between two initial sub-resolution auxiliary graphic seeds to obtain sub-resolution auxiliary graphic seeds;

[0078] The endpoint set of the sub-resolution auxiliary image is generated by expanding the sub-resolution auxiliary image seed.

[0079] The purpose of performing photolithographic simulation on the original mask pattern in this embodiment of the invention is to calculate the gradient map of the original pattern with respect to specific evaluation indicators, including exposure intensity and contrast.

[0080] In this embodiment of the invention, a maximum point is defined as follows: if the gradient value of a pixel in the gradient map is higher than the values ​​of its neighboring pixels in the four directions (up, down, left, and right), then the point is considered a maximum point.

[0081] The definition of a local minimum is: if the gradient value of a pixel in the gradient map is lower than the values ​​of its four adjacent pixels (up, down, left, right, and right), then the pixel is considered a local minimum.

[0082] To ensure that the final selected sub-resolution auxiliary image seeds are both effective and not too dense, this embodiment of the invention calculates the Euclidean distance between all initial sub-resolution auxiliary image seeds, and filters all initial sub-resolution auxiliary image seeds based on the distance between two initial sub-resolution auxiliary image seeds to obtain sub-resolution auxiliary image seeds, including:

[0083] Calculate the Euclidean distance between all initial sub-resolution auxiliary graphic seeds. For points whose Euclidean distance is too close (e.g., less than a certain preset threshold), only retain the initial sub-resolution auxiliary graphic seed that is closer to the center point. For example, when selecting two points, retain the extreme point that is closer to the center point and discard the other point. The remaining initial sub-resolution auxiliary graphic seed is the sub-resolution auxiliary graphic seed.

[0084] Specifically, based on the sub-resolution auxiliary image seed, an endpoint set of sub-resolution auxiliary graphics is generated, including:

[0085] Starting from each sub-resolution auxiliary graphic seed, and extending it to 12 target directions with a preset length, sub-resolution auxiliary graphics are obtained, and the extension endpoint is taken as the endpoint set of the sub-resolution auxiliary graphics.

[0086] In this embodiment of the invention, the target direction can be a uniformly distributed angle (e.g., one direction every 30 degrees) to ensure uniform coverage of the sub-resolution auxiliary graphics.

[0087] Specifically, a curve mask is generated from the merged endpoint set using a heuristic algorithm, including:

[0088] Multiple initial Bézier curves are constructed using the merged endpoint set, and the endpoint of each initial Bézier curve is used as the starting point of the next initial Bézier curve.

[0089] The first and second control points of each initial Bézier curve segment are generated using a heuristic algorithm.

[0090] Generate Bézier curves based on the start point, end point, first control point, and second control point of each initial Bézier curve;

[0091] Generate a curve mask based on all Bézier curves.

[0092] In this embodiment of the invention, the Bézier curve is represented by two endpoints and two midpoints, and its expression is:

[0093] ;

[0094] in, What does it mean? , Indicates the starting point. Indicates endpoints, This represents the first control point, i.e., the first intermediate point. This indicates the second control point, i.e., the second intermediate point.

[0095] In this embodiment of the invention, since the curves are connected end to end, the endpoint of the current Bézier curve is actually the starting point of the next Bézier curve.

[0096] Specifically, control points for each initial Bézier curve segment are generated using a heuristic algorithm, including:

[0097] Construct an angle bisector using the endpoints of three adjacent initial Bézier curves;

[0098] Based on the concavity and convexity of the curve, rotate the angle bisector by 90° to obtain the rotated angle bisector;

[0099] The first control point is determined by moving along the positive direction of the rotated angle bisector according to a preset ratio, based on the distance between the endpoints of the first two adjacent initial Bézier curves.

[0100] The second control point is determined by moving along the opposite direction of the rotated angle bisector according to a preset ratio, based on the distance between the endpoints of the last two adjacent initial Bézier curves.

[0101] In this embodiment of the invention, the angle bisector is rotated by 90° according to the concavity and convexity of the curve to obtain the rotated angle bisector, including:

[0102] For a concave Bézier curve, the angle bisector is rotated 90° counterclockwise;

[0103] For a convex Bézier curve, the angle bisector is rotated 90° clockwise.

[0104] In this embodiment of the invention, the method for determining concavity / convexity is the cross product method, and the specific process is as follows:

[0105] structure point to Vector sum point to The cross product of two vectors is represented by the following formula:

[0106] ;

[0107] If the cross product is greater than 0, it is a convex angle; otherwise, it is a concave angle.

[0108] In this embodiment of the invention, both the first control point and the second control point are distributed on the angle bisector after rotation. according to and The position is determined by moving the distance between them along the positive direction after rotation in a certain proportion; similarly, according to and The position is determined by moving the distance between them in the opposite direction after rotation according to a certain ratio. The ratio can be set according to design requirements. In this embodiment of the invention, the ratio is set to 0.3.

[0109] In this embodiment of the invention, a curve mask is simulated to obtain a mask plate, including:

[0110] The mask pattern will generate a projectivity distribution map using the following formula:

[0111] ;

[0112] in, Indicates the projection rate. Indicates Fourier transform, This represents the inverse Fourier transform. Indicates a curve mask. The kernel function representing the approximation of the simulation process is provided by the open-source system ICCAD2013contest. Indicates coefficient;

[0113] Then set a threshold. When the transmittance corresponding to a pixel exceeds this threshold, the transmittance distribution map is considered to be visible in the mask.

[0114] .

[0115] In this embodiment of the invention, after simulation, the simulation is compared with the original pattern to obtain evaluation indicators. The evaluation indicators mainly consist of two parts: difference of squares. And PVBand, which measures the robustness of the mask to different process conditions, assumes the original target image is The final generated mask pattern varies in size depending on the process conditions, resulting in minimum, general, and maximum patterns, respectively. , as well as Then the expressions for these two evaluation indicators are:

[0116] ;

[0117] ;

[0118] During the optimization process, the rows are passed in reverse to obtain the gradient of the evaluation metric with respect to the endpoint set. In the forward pass, endpoints generate mask patterns using a heuristic algorithm. These mask patterns are then used in photolithography simulation to obtain the final mask. Finally, the evaluation metric is calculated. According to the chain rule of directional propagation, the gradient of the final evaluation metric with respect to the endpoint set should be the product of the gradients at each stage of the forward pass—namely, the mask generation stage and the simulation stage. This can be expressed by the formula:

[0119] ;

[0120] In photolithography simulation, the gradient of the mask with respect to two parameters is:

[0121]

[0122] ;

[0123] ;

[0124] in, This is a set of kernel functions for lithography simulation. This is the result after rotating the matrix by 180°. It is a conjugate matrix.

[0125] In mask generation, the gradient of each endpoint corresponding to a pixel is calculated using the central difference method:

[0126] ;

[0127] ;

[0128] Specifically, the expression for optical proximity correction of the vertex positions of the mask using a gradient-based optimization method is as follows:

[0129] ;

[0130] in, The total loss function includes the squared difference index L² and the robustness index L. pvb , Represents the endpoint set, Indicates a mask. This represents the gradient of the loss function with respect to the mask during the photolithography simulation stage. This represents the gradient of the mask in the x-direction at the endpoint. This represents the gradient of the mask in the y-direction at the endpoint.

[0131] This invention obtains an original mask pattern from a target layout file. The original mask pattern includes multiple curve segments. After initializing the original mask pattern, the initial endpoints of each curve segment are extracted to generate an endpoint set. The original mask pattern is simulated to obtain a gradient map, and an endpoint set of sub-resolution auxiliary graphics is obtained based on the gradient map. The endpoint set of the sub-resolution auxiliary graphics is merged with the endpoint set to obtain a merged endpoint set. A curve mask is generated using a heuristic algorithm, and the curve mask is simulated to obtain a mask plate. Optical proximity correction is performed on the vertex positions of the mask plate using a gradient-based optimization method to obtain the optical proximity correction result of the mask plate. Compared with the prior art, this invention converts the traditional Manhattan shape mask into a curve mask through initialization, extracts the initial endpoints, simulates the original mask pattern to obtain a gradient map, and obtains an endpoint set of sub-resolution auxiliary graphics based on the gradient map. The endpoint set of the sub-resolution auxiliary graphics is merged with the endpoint set to participate in optimization. Finally, an optical proximity correction is performed on the vertex positions of the mask plate using a gradient-based optimization method, which improves the accuracy of optical proximity correction.

[0132] Corresponding to the optical proximity correction method for curved masks described in the above embodiments, such as Figure 2 As shown, this embodiment of the invention also provides an optical proximity correction device 100 for curved masks, the optical proximity correction device 100 comprising:

[0133] The extraction module 101 is used to obtain the original mask pattern from the target layout file. The original mask pattern includes multiple curve segments. After initializing the original mask pattern, the initial endpoints of each curve segment are extracted to generate an endpoint set.

[0134] The simulation module 102 is used to simulate the original mask pattern, obtain the gradient map, and obtain the endpoint set of the sub-resolution auxiliary graphics based on the gradient map.

[0135] The merging module 103 is used to merge the endpoint sets of the sub-resolution auxiliary graphics to obtain the merged endpoint set;

[0136] The generation module 104 is used to generate a curve mask from the merged endpoint set using a heuristic algorithm, and to simulate the curve mask to obtain the mask version.

[0137] The correction module 105 is used to perform optical proximity correction on the vertex position of the mask using a gradient-based optimization method to obtain the optical proximity correction result of the mask.

[0138] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0139] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0140] This invention also provides a terminal device, such as... Figure 3 As shown, the terminal device D10 of this embodiment includes: at least one processor D100 ( Figure 3 The diagram shows only one processor, a memory D101, and a computer program D102 stored in the memory D101 and executable on the at least one processor D100. When the processor D100 executes the computer program D102, it implements the above-described optical proximity correction method for curved masks.

[0141] The terminal device D10 can be a desktop computer, laptop, handheld computer, server, server cluster, or cloud server, etc. This terminal device may include, but is not limited to, a processor D100 and a memory D101. Those skilled in the art will understand that... Figure 3 This is merely an example of terminal device D10 and does not constitute a limitation on terminal device D10. It may include more or fewer components than shown in the figure, or combine certain components, or different components, such as input / output devices, network access devices, etc.

[0142] The processor D100 can be a central processing unit (CPU), or it can be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0143] In some embodiments, the memory D101 may be an internal storage unit of the terminal device D10, such as a hard disk or memory of the terminal device D10. In other embodiments, the memory D101 may be an external storage device of the terminal device D10, such as a plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, etc., equipped on the terminal device D10. Furthermore, the memory D101 may include both internal and external storage units of the terminal device D10. The memory D101 is used to store the operating system, applications, bootloader, data, and other programs, such as the program code of the computer program. The memory D101 can also be used to temporarily store data that has been output or will be output.

[0144] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, and they will not be repeated here.

[0145] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here. The above description is a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An optical proximity correction method for curved masks, characterized in that, include: Step 1: Obtain the original mask pattern from the target layout file. The original mask pattern includes multiple curve segments. After initializing the original mask pattern, extract the initial endpoints of each curve segment to generate an endpoint set. Step 2: Simulate the original mask pattern to obtain a gradient map, and obtain the endpoint set of the sub-resolution auxiliary graphics based on the gradient map; Step 3: Merge the endpoint set of the sub-resolution auxiliary graphic with the endpoint set to obtain the merged endpoint set; Step 4: Generate a curve mask from the merged endpoint set using a heuristic algorithm, and simulate the curve mask to obtain the mask version; Step 5: Perform optical proximity correction on the vertex positions of the mask using a gradient-based optimization method to obtain the optical proximity correction result of the mask.

2. The optical proximity correction method for curved masks according to claim 1, characterized in that, Step 1 includes: After obtaining the coordinate information of each element in the target layout file using open-source tools, all elements are curve-converted to obtain the original mask pattern, which includes multiple curve segments. The original mask pattern is initialized to obtain the initialized mask pattern; The elements in the initialized mask pattern are segmented to obtain multiple curves, and the segmentation points are used as the initial endpoints of each curve to generate an endpoint set.

3. The optical proximity correction method for curved masks according to claim 2, characterized in that, Curveize all elements to obtain the original mask pattern, including: Replace the corner of each element with a quarter-circle arc to obtain the original mask pattern.

4. The optical proximity correction method for curved masks according to claim 2, characterized in that, Step 2 includes: Photolithographic simulation was performed on the original mask pattern to obtain a gradient map; In the gradient map, all pixels are traversed, and pixels with gradient values ​​higher than their neighboring pixels are designated as maxima, while pixels with gradient values ​​lower than their neighboring pixels are designated as minima. Based on the maximum and minimum points, local extreme points are found in the gradient graph, and all local extreme points are used as initial sub-resolution auxiliary graph seeds. Calculate the Euclidean distance between all initial sub-resolution auxiliary graphic seeds, and filter all initial sub-resolution auxiliary graphic seeds based on the distance between two initial sub-resolution auxiliary graphic seeds to obtain sub-resolution auxiliary graphic seeds; The sub-resolution auxiliary image seed is expanded to generate the endpoint set of the sub-resolution auxiliary graphic.

5. The optical proximity correction method for curved masks according to claim 4, characterized in that, Based on the sub-resolution auxiliary image seed, the endpoint set of the sub-resolution auxiliary graphic is generated by expansion, including: Starting from each sub-resolution auxiliary graphic seed, and extending it to 12 target directions with a preset length, sub-resolution auxiliary graphics are obtained, and the extension endpoint is taken as the endpoint set of the sub-resolution auxiliary graphics.

6. The optical proximity correction method for curved masks according to claim 4, characterized in that, A curve mask is generated from the merged endpoint set using a heuristic algorithm, including: Multiple initial Bézier curves are constructed using the merged endpoint set, and the endpoint of each initial Bézier curve is used as the starting point of the next initial Bézier curve. The first and second control points of each initial Bézier curve segment are generated using a heuristic algorithm. Generate Bézier curves based on the start point, end point, first control point, and second control point of each initial Bézier curve; Generate a curve mask based on all Bézier curves.

7. The optical proximity correction method for curved masks according to claim 6, characterized in that, Control points for each initial Bézier curve segment are generated using a heuristic algorithm, including: Construct an angle bisector using the endpoints of three adjacent initial Bézier curves; The angle bisector is rotated by 90° based on the concavity and convexity of the curve to obtain the rotated angle bisector. The first control point is determined by moving along the positive direction of the rotated angle bisector according to a preset ratio, based on the distance between the endpoints of the first two adjacent initial Bézier curves. The second control point is determined by moving along the opposite direction of the rotated angle bisector according to a preset ratio, based on the distance between the endpoints of the last two adjacent initial Bézier curves.

8. The optical proximity correction method for curved masks according to claim 1, characterized in that, The expression for optical proximity correction of the vertex positions of the mask using a gradient-based optimization method is as follows: ； in, Represents the total loss function. Represents the endpoint set, Indicates a mask. This represents the gradient of the loss function with respect to the mask during the photolithography simulation stage. This represents the gradient of the mask in the x-direction at the endpoint. This represents the gradient of the mask in the y-direction at the endpoint.

9. An optical proximity correction device for curved masks, characterized in that, include: An extraction module is used to obtain the original mask pattern from the target layout file. The original mask pattern includes multiple curve segments. After initializing the original mask pattern, the initial endpoints of each curve segment are extracted to generate an endpoint set. The simulation module is used to simulate the original mask pattern, obtain a gradient map, and obtain the endpoint set of the sub-resolution auxiliary graphics based on the gradient map. The merging module is used to merge the endpoint set of the sub-resolution auxiliary graphic with the endpoint set to obtain a merged endpoint set; The generation module is used to generate a curve mask from the merged endpoint set using a heuristic algorithm, and to simulate the curve mask to obtain a mask version. The correction module is used to perform optical proximity correction on the vertex positions of the mask using a gradient-based optimization method to obtain the optical proximity correction result of the mask.

10. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the optical proximity correction method for curved masks as described in any one of claims 1 to 8.

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