Optical proximity effect correction method, mask and readable storage medium

Abstract

The invention relates to an optical proximity effect correction method, a mask and a readable storage medium. The method comprises the following steps: acquiring a mask design pattern; simulating the mask design pattern according to an OPC model to obtain a simulated exposure pattern; calculating the edge placement error of the simulation exposure pattern and the mask design pattern at each target point; according to the edge placement error, adjusting each correction segment of the mask design pattern of which the edge is analyzed and segmented to obtain a corrected pattern; the line end graph, limited by the MRC, in the corrected graph is specially corrected, a mask plate making graph is obtained, and the edge of the line end graph comprises a short edge and two long edges connected with the short edge. According to the invention, the OPC correction precision can be improved.

Description

Technical Field

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

[0002] With the rapid development of Ultra Large Scale Integration (ULSI), integrated circuit manufacturing processes have become increasingly complex and sophisticated. In critical layers of technology nodes at 0.18 micrometers and below, such as TO (active region layer), GT (gate oxide layer), and An (metal 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 248 nanometers. 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. To eliminate these errors, the OPC (Optical Proximity Correction) method is typically used to correct the design pattern of the mask.

[0003] Line-end shortening, a common optical proximity effect, significantly impacts most critical layers. For example, in metallic layers, there are typically holes (e.g., contact holes) below the line-end. Severe shortening can cause anomalies in the metal enclosure. An exemplary correction method is to extend the line-end outwards, forming a hammer structure around the target pattern at the line-end, serving as a mask pattern. See also... Figure 1a A segment at the head of a line-end graphic is called a line-end. You can place split points along the edge of the line-end graphic to divide the edge. See [link to documentation]. Figure 1a The segmented edges can be translated along their normal direction to form a Hammer structure, which serves as a mask pattern. The exposure pattern (simulation result) formed after the Hammer structure mask pattern is exposed is shown below. Figure 1b As shown. Figure 1b The target graphic in the middle is Figure 1a Line-end graphics in the image.

[0004] The inventors discovered in actual production that when there are other adjacent mask patterns outside the line-end, it may lead to a decrease in OPC accuracy. Summary of the Invention

[0005] Therefore, it is necessary to provide an optical proximity effect correction method so that high OPC accuracy can be obtained even when there are other adjacent mask patterns outside the line-end.

[0006] An optical proximity effect correction method includes: acquiring a mask design pattern; simulating the mask design pattern according to an OPC model to obtain a simulated exposure pattern; acquiring the edge placement error between the simulated exposure pattern and the mask design pattern at each target point; adjusting each correction segment of the mask design pattern whose edges have been analytically segmented according to the edge placement error to obtain a corrected pattern; and performing special correction on the line-end patterns in the corrected pattern that are limited by MRC to obtain a mask plate-making pattern, wherein the edge of the line-end pattern includes a short side and two long sides connected to the short side; wherein the line-end pattern limited by MRC is: during the adjustment process The spacing between the graphic obtained by the midline end graphic transformation and the graphics obtained by the transformation of other adjacent graphics does not meet the spacing requirements specified in the mask rule check; the special correction includes: re-segmenting the i-th correction segment closest to the short side among the two long sides of the mask design graphic that has been parsed into i new correction segments, j>i; simulating the re-segmented midline end graphic constrained by MRC according to the OPC model to obtain a new simulated exposure graphic and obtain the corresponding edge placement error; adjusting the position of the j new correction segments according to the new simulated exposure graphic and its corresponding edge placement error to obtain the mask plate making graphic.

[0007] The aforementioned optical proximity effect correction method selects the line-end pattern limited by MRC (Mean Correlation Control), re-segments the correction segment near the line end to obtain a shorter new correction segment, and then adjusts the position of the new correction segment according to the edge placement error to finally obtain the mask pattern. This method can achieve high OPC correction accuracy even when there are other adjacent mask patterns outside the line end.

[0008] In one embodiment, the corresponding edge placement error includes a target edge placement error, which is the edge placement error to which the short side can be moved outward along the normal direction of the short side, provided that the spacing requirement is met.

[0009] In one embodiment, the special correction further includes obtaining the target edge placement error of the line-end pattern constrained by MRC; the step of simulating the re-segmented line-end pattern constrained by MRC according to the OPC model to obtain a new simulated exposure pattern and obtaining the corresponding edge placement error includes: adjusting the surrounding graphic environment of the re-segmented line-end pattern constrained by MRC; obtaining a first simulated exposure pattern of the re-segmented line-end pattern constrained by MRC based on a first surrounding graphic environment and a second simulated exposure pattern based on a second surrounding graphic environment; calculating the first simulated exposure pattern and the re-segmented line-end pattern constrained by MRC. The edge placement error at each target point is calculated, and the re-segmented line-end pattern constrained by MRC is adjusted accordingly to obtain a first corrected pattern; the edge placement error between the second simulated exposure pattern and the re-segmented line-end pattern constrained by MRC at each target point is calculated, and the re-segmented line-end pattern constrained by MRC is adjusted accordingly to obtain a second corrected pattern; the step of adjusting the position of the j new correction segments according to the new simulated exposure pattern and its corresponding edge placement error includes: adjusting the position of the j new correction segments according to the target edge placement error of the line-end pattern constrained by MRC, and the first corrected pattern and the second corrected pattern.

[0010] In one embodiment, j=2i.

[0011] In one embodiment, the resegmentation involves dividing each of the i-th correction segments into two new correction segments.

[0012] In one embodiment, the number of the i-th correction segments in each long side is greater than 0 and less than 4.

[0013] In one embodiment, the number of the i-th correction segments in each long side is 2.

[0014] In one embodiment, the j new correction segments in the mask pattern, from closest to furthest from the short side, include a first segment, a second segment, a third segment, and a fourth segment, and df11 > df12 > df22 > df21, where df11 is the outward displacement distance of the first segment in the mask pattern relative to the mask design pattern, df12 is the outward displacement distance of the second segment in the mask pattern relative to the mask design pattern, df21 is the outward displacement distance of the third segment in the mask pattern relative to the mask design pattern, and df22 is the outward displacement distance of the fourth segment in the mask pattern relative to the mask design pattern.

[0015] It is also necessary to provide a mask, which is made from a mask pattern obtained according to the optical proximity correction method described in any of the above embodiments.

[0016] It is also necessary to provide a readable storage medium on which a computer program is stored, which, when executed by a processor, implements the steps of the optical proximity effect correction method described in any of the above embodiments.

[0017] It is also necessary to provide 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 the optical proximity effect correction method described in any of the above embodiments.

[0018] It is also necessary to provide a computer program product, including a computer program that, when executed by a processor, implements the steps of the optical proximity effect correction method described in any of the foregoing embodiments. Attached Figure Description

[0019] 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.

[0020] Figure 1a This is a schematic diagram of an exemplary line-end graphic. Figure 1b Yes Figure 1a A schematic diagram of the mask pattern and the corresponding exposure pattern obtained after exemplary optical proximity correction of the line-end pattern shown.

[0021] Figure 2 This is an exemplary schematic diagram of mask design graphic analysis and segmentation and simulated exposure in the OPC process;

[0022] Figure 3 This is an exemplary diagram illustrating parsing and segmentation using the Inter-feature segmentation command;

[0023] Figure 4 This is a flowchart of an optical proximity effect correction method in one embodiment of this application;

[0024] Figure 5 This is a flowchart of an optical proximity effect correction method in another embodiment of this application;

[0025] Figure 6 This is a flowchart of a sub-step of step S450 in one embodiment of this application;

[0026] Figure 7a This is a schematic diagram of i correction segments in one embodiment. Figure 7b This is a schematic diagram showing the j new corrected segments obtained after re-segmentation;

[0027] Figure 8 This is a flowchart of a sub-step of step S450 in another embodiment of this application;

[0028] Figure 9a This is a comparison between the mask pattern of the line-end pattern obtained in one embodiment of this application and a comparative example. Figure 9b This is a comparison between the exposure pattern of the line-end pattern obtained in one embodiment of this application and a comparative example. Detailed Implementation

[0029] 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.

[0030] 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.

[0031] It should be understood that when a component or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other components or layers, it may be directly on, adjacent to, connected to, or coupled to other components or layers, or there may be intervening components or layers. Conversely, when a component is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other components or layers, there are no intervening components or layers. The term "connection" in this specification, if the connected circuits, modules, units, etc., involve the transmission of electrical signals or data, should be understood as "electrical connection," "communication connection," etc. It should be understood that although the terms first, second, third, etc., may be used to describe various components, parts, areas, layers, and / or portions, these components, parts, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one component, part, area, layer, or portion from another component, part, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, region, layer or portion discussed below may be represented as a second element, component, region, layer or portion.

[0032] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein for convenience of description 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 are intended to also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, then the element or feature described as “below” or “under” the other element or feature will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or otherwise) and the spatial descriptive terms used herein will be interpreted accordingly.

[0033] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It will be understood that “at least one” means one or more, and “a plurality” means two or more. “At least a portion of an element” means part or all of an element. It should also be understood that the terms “compose” and / or “comprising,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0034] Embodiments of the invention are described herein with reference to cross-sectional views that serve as schematic diagrams of ideal embodiments (and intermediate structures). Thus, variations in the shape shown can be anticipated 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 include shape deviations due to, for example, manufacturing processes. For example, 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 are not intended to show the actual shapes of the regions of the device and are not intended to limit the scope of the invention.

[0035] An exemplary computer-aided software tool method for optical proximity correction (OPC) involves first identifying the edges of a photomask design pattern using OPC software, and then dividing these edges into numerous small correction segments, allowing each segment to move freely. Target points are then placed on each correction segment. The OPC software then simulates the image after photolithography exposure based on an OPC model and compares it with the photomask design pattern (e.g., ...). Figure 2 As shown in the figure, the difference between the simulated graphic and the design graphic at the target point is calculated. This difference is called the Edge Placement Error (EPE), a metric used to measure the quality of the correction. During runtime, the OPC software moves the edge position of the mask design graphic and calculates the corresponding edge placement error. This process is repeated until the calculated edge placement error reaches an acceptable value. A smaller EPE value indicates a better OPC correction result, and vice versa. The mask design graphic segmentation and corresponding results during the OPC process are shown in the figure. Figure 3 As shown, Figure 3 The left half represents the mask design and the position of the splitting points. The black dots on the edge of the original pattern (i.e., the mask design) indicate the splitting points, dividing the edge into several correction segments of varying lengths. The corrected OPC result (i.e., the corrected mask pattern) is as follows: Figure 3 As shown in the right half.

[0036] The exemplary OPC technique compensates for the shortening effect by extending the line-end outward. The more severe the shortening, the greater the outward movement of the line-end. When there are other adjacent graphics outside the line-end, due to MRC (Mask Rule Check) restrictions, the distance between the line-end and the adjacent graphics must not be less than a preset distance threshold. Therefore, the outward extension of the line-end during OPC correction may be limited. In this case, the compensation for the shortening effect is insufficient, resulting in reduced OPC correction accuracy.

[0037] This application proposes an optical proximity effect correction method that improves the correction accuracy of OPC while satisfying MRC.

[0038] Figure 4 This is a flowchart of an optical proximity effect correction method in one embodiment of this application, including:

[0039] S410, obtain the mask design graphic.

[0040] After designing an integrated circuit according to actual needs, design patterns at various layout levels that match the needs are obtained, which serve as mask design patterns.

[0041] S420 simulates the mask design pattern based on the OPC model to obtain the simulated exposure pattern.

[0042] OPC software can be used to simulate exposure of the mask design pattern. This software can have preset simulation exposure rules, which can be modified by those skilled in the art. This application does not limit the specific simulation exposure rules. In one embodiment of this application, the optical proximity effect correction method may further include steps S412 and S414, see [link to relevant documentation]. Figure 5 Step S412 involves analytically dissectioning the outer edge of the mask design pattern into multiple correction segments. This analytical dissection includes dividing the edges of the mask design pattern into many small correction segments, with each segmentation point dividing the edge into several correction segments of varying lengths. Analytical dissection can be performed using OPC software. Step S414 involves placing target points on each correction segment obtained from the analytical dissection. After step S414 is completed, the mask design pattern with target points placed on each correction segment is simulated to obtain a simulated exposure pattern.

[0043] S430 calculates the edge placement error between the simulated exposure pattern and the mask design pattern at each target point.

[0044] In one embodiment of this application, the edge placement error is the distance obtained by subtracting the position of the corresponding target point on the mask design pattern from the position of the target point on the simulated exposure pattern. The value of the edge placement error can be positive or negative.

[0045] S440 adjusts the mask design based on edge placement error to obtain a corrected design.

[0046] In one embodiment of this application, each correction segment of the mask design pattern is moved according to the edge placement error, so that the value of the edge placement error of each correction segment tends to zero, or the absolute value of the edge placement error of each correction segment tends to a very small value.

[0047] S450 performs special corrections on the line-end patterns limited by MRC to obtain the mask plate-making pattern.

[0048] Line-end graphics in mask design graphics, such as Figure 1a As shown, this includes the line-end (a short side) and two long sides connecting to the two ends of the line-end. Figure 1aIn the illustrated embodiment, the short side and long side of the line-end graphic form a right angle. As mentioned earlier, the spacing between the line-end on the mask and adjacent graphics must not be less than a preset distance threshold. Therefore, during the adjustment process in step S440, it is possible that the spacing between the graphic obtained from the line-end graphic change and the graphic obtained from the adjacent graphic change does not meet the spacing requirements specified by the mask rule check (i.e., the spacing is less than the distance threshold specified by MRC). For line-end graphics that exhibit this situation, they are selected and specially corrected to obtain the mask pattern for that line-end graphic. (Refer to...) Figure 6 The specific steps for special corrections are as follows:

[0049] S451, further subdivide a portion of the long side of the line-end graphic that is close to the short side.

[0050] In the mask design graphic that has undergone analytical segmentation, the i-th correction segment closest to the short side among the two long sides of the line-end graphic is further segmented to obtain j new correction segments, where i and j are positive integers and j>i. In one embodiment of this application, the number of i correction segments in each long side is greater than 0 and less than 4 (i.e., equal to 1, 2 or 3).

[0051] exist Figure 7a In the illustrated embodiment, i=2 for each long side, meaning that the two corrected segments within each long side are further segmented. Figure 7a Taking the two correction segments F1 and F2 as an example, after further segmentation, four new correction segments F11, F12, F21, and F22 are obtained.

[0052] S453, based on the simulated exposure pattern of the re-segmented line-end pattern, calculates the corresponding edge placement error.

[0053] The OPC model is used to simulate the line-end pattern after resegmentation due to MRC limitations, resulting in a new simulated exposure pattern, and the corresponding edge placement error is calculated.

[0054] S455 adjusts the position of the correction segment based on the new simulated exposure pattern and the corresponding edge placement error.

[0055] Based on the new simulated exposure pattern and its corresponding edge placement error, the positions of j new correction segments are adjusted to obtain the mask pattern for the line-end pattern constrained by MRC. The line-end position of the line-end pattern constrained by MRC in the mask pattern remains the same as that in the correction pattern, which is the farthest position that can be moved outward along the normal direction (of the line-end) while meeting the MRC spacing requirements.

[0056] The aforementioned optical proximity effect correction method selects the line-end pattern limited by MRC (Mean Correction Rate), re-segments the correction segments (F1, F2) near the line end to obtain shorter new correction segments (F11, F12, F21, F22), and then adjusts the position of the new correction segments according to the edge placement error to finally obtain the mask pattern. This method can achieve high OPC correction accuracy even when there are other adjacent mask patterns outside the line end.

[0057] In one embodiment of this application, the corresponding edge placement error in step S453 includes the target edge placement error. The target edge placement error is the edge placement error to which the line-end can be moved outward along the normal direction (of the line-end) while meeting the aforementioned MRC spacing requirements. That is, projecting the short side E to the adjacent side and adjusting the offset, where EPE is a reference value for the short side E.

[0058] Reference Figure 8 In one embodiment of this application, step S450 specifically includes:

[0059] S510, obtain the target edge placement error of the line-end graphic due to MRC limitations.

[0060] The target edge placement error is denoted as x'.

[0061] S520 re-segments a portion of the long side of a line-end graphic that is near the short side due to MRC limitations.

[0062] The same as step S451, so it will not be repeated here.

[0063] S530, adjusts the surrounding graphic environment of the re-segmented line-end graphic.

[0064] The surrounding graphic environment refers to the distance between the line-end graphic and adjacent graphics and / or the shape of adjacent graphics. It should be noted that the adjusted surrounding graphic environment should also make the line-end graphic restricted by MRC.

[0065] S540 acquires simulated exposure patterns of the re-divided line-end pattern under two different surrounding pattern environments.

[0066] Based on the OPC model, OPC operations are performed on the re-segmented line-end graphics under two different surrounding graphic environments to obtain a first OPC graphic under the first surrounding graphic environment and a second OPC graphic under the second surrounding graphic environment. Then, based on the OPC model, the first OPC graphic and the second OPC graphic are subjected to simulated exposure to obtain a first simulated exposure graphic under the first surrounding graphic environment and a second simulated exposure graphic under the second surrounding graphic environment.

[0067] S552, calculate the edge placement error (denoted as the first edge placement error) between the first simulated exposure pattern and the re-divided line end pattern at each target point.

[0068] The placement error of the first edge of the line-end is denoted as x1.

[0069] S562, adjust the re-divided line end pattern according to the first edge placement error to obtain the first corrected pattern.

[0070] Based on the first edge placement error, move each new correction segment (keeping the line-end unchanged) so that the edge placement error value of each new correction segment approaches zero, or so that the absolute value of the edge placement error of each correction segment approaches a very small value.

[0071] S554, calculate the edge placement error (denoted as the second edge placement error) between the second simulated exposure pattern and the re-divided line end pattern at each target point.

[0072] The placement error of the second edge of the line-end is denoted as x2. In one embodiment of this application, step S530 adjusts the surrounding graphic environment so that the absolute value of the difference between |x1| and |x2| is as large as possible.

[0073] S564, adjust the re-divided line end graphics according to the second edge placement error to obtain the second corrected graphics.

[0074] Based on the second edge placement error, move each new correction segment (keeping the line-end unchanged) so that the edge placement error value of each new correction segment approaches zero, or so that the absolute value of the edge placement error of each correction segment approaches a very small value.

[0075] S570, adjust the position of the new correction segment according to the target edge placement error and the first and second correction graphics.

[0076] by Figure 7b Taking the illustrated embodiment as an example, assume that the movement amounts of the new correction segments F11, F12, F21, and F22 in the correction pattern obtained in step S562 / S564 relative to the correction segments of the line-end patterns in the mask design pattern are df11, df12, df21, and df22, respectively. These movement amounts can be positive or negative, with positive values ​​indicating movement outwards and negative values ​​indicating movement inwards. The definition is as follows:

[0077] df11=a1x+b1(1)

[0078] df12=a2x+b2(2)

[0079] df21=a3x+b3(3)

[0080] df22=a4x+b4(4)

[0081] Where a1~a4, b1~b4 are constants, the values ​​of which are determined by the OPC model used in step S420 and / or step S540; x is the edge placement error of edge E (line-end). For the first correction pattern, df11, df12, df21, df22 and x are known quantities, which are substituted into equations (1) to (4); similarly, df11, df12, df21, df22 and x of the second correction pattern are substituted into equations (1) to (4), from which a1~a4, b1~b4 can be calculated. Then, the calculated a1~a4, b1~b4, and x=x' are substituted into equations (1) to (4) to calculate the values ​​of df11, df12, df21, and df22, and the positions of the j new correction segments are adjusted accordingly to obtain the mask plate making pattern. Where x' is the target edge placement error obtained in step S510.

[0082] In another embodiment of this application, after re-segmentation in step S520, OPC operations are performed on the re-segmented line-end graphics according to the OPC model to obtain an OPC graphic; then, simulated exposure is performed on the OPC graphic according to the OPC model to obtain a simulated exposure graphic; next, the edge placement error of the simulated exposure graphic and the re-segmented line-end graphics is calculated as x' in the aforementioned formulas (1) to (4). It can be understood that step S510 is not performed in this embodiment.

[0083] In one embodiment of this application, the mask pattern is defined as df11> df12> df22> df21.

[0084] Figure 9a This figure shows a comparison between a mask pattern of a line-end pattern obtained according to an embodiment of this application and a comparative example. The graphic lines of the embodiment of this application are highlighted with bold dashed lines in the figure. Figure 9b This is a comparison between the exposure pattern of the line-end pattern obtained in one embodiment of this application and the comparative example. It can be seen that in this embodiment, the line-end shortening is improved from 0.032 micrometers in the comparative example to 0.005 micrometers, which improves the OPC correction accuracy, thereby increasing the process window and reducing the risk of metal cladding process.

[0085] In one embodiment of this application, j=2i, and the correction segment is further divided into two new correction segments. Alternatively, it can be divided into two equal new correction segments.

[0086] This application provides a mask made from a mask pattern obtained by the optical proximity effect correction method according to any of the above embodiments.

[0087] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0088] This application also provides a readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the optical proximity effect correction method described in any of the above embodiments.

[0089] 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 the optical proximity effect correction method described in any of the above embodiments.

[0090] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the optical proximity effect correction method described in any of the foregoing embodiments.

[0091] It should be understood that although the steps in the flowchart of this application are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowchart of this application may include multiple steps or multiple stages, which are not necessarily completed at the same time, but may be executed at different times, and the execution order of these steps or stages is not necessarily sequential, but may be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0092] 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.

[0093] 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.

[0094] 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, comprising: Obtain the mask design graphic; The mask design pattern is simulated based on the OPC model to obtain the simulated exposure pattern; Obtain the edge placement error of the simulated exposure pattern and the mask design pattern at each target point; The correction graphics are obtained by adjusting each correction segment of the mask design graphic, which has been analytically segmented based on the edge placement error; Special corrections are made to the line-end patterns in the correction pattern that are restricted by MRC to obtain the mask plate-making pattern. The edge of the line-end pattern includes a short side and two long sides connected to the short side. The line-end pattern restricted by MRC is defined as follows: during the adjustment process, the spacing between the pattern obtained by the change of the line-end pattern and the pattern obtained by the change of other adjacent patterns does not meet the spacing requirements specified by the mask rule check. The specific modifications include: In the mask design graphic that has undergone analytical segmentation, the i-th correction segment closest to the short side among the two long sides is further segmented to obtain j new correction segments, where j>i; The OPC model is used to simulate the re-segmented line-end pattern limited by MRC to obtain a new simulated exposure pattern and the corresponding edge placement error is obtained. Based on the new simulated exposure pattern and its corresponding edge placement error, the positions of the j new correction segments are adjusted to obtain the mask pattern.

2. The optical proximity effect correction method according to claim 1, characterized in that, The corresponding edge placement error includes the target edge placement error, which is the edge placement error to which the short side can be moved outward along the normal direction of the short side, provided that the spacing requirement is met.

3. The optical proximity effect correction method according to claim 2, characterized in that, The special correction also includes obtaining the target edge placement error of the line-end graphics due to MRC limitations; The step of simulating the re-segmented line-end pattern constrained by MRC according to the OPC model to obtain a new simulated exposure pattern and acquiring the corresponding edge placement error includes: Adjust the surrounding graphic environment of the re-segmented line-end graphic that is restricted by MRC; The re-segmented line-end pattern constrained by MRC is obtained as a first simulated exposure pattern based on a first surrounding pattern environment, and a second simulated exposure pattern based on a second surrounding pattern environment; Calculate the edge placement error of the first simulated exposure pattern and the re-segmented line-end pattern restricted by MRC at each target point, and adjust the re-segmented line-end pattern restricted by MRC accordingly to obtain the first corrected pattern. Calculate the edge placement error of the second simulated exposure pattern and the re-segmented line-end pattern restricted by MRC at each target point, and adjust the re-segmented line-end pattern restricted by MRC accordingly to obtain the second corrected pattern. The step of adjusting the positions of the j new correction segments based on the new simulated exposure pattern and its corresponding edge placement error includes: Based on the target edge placement error of the line-end graphic limited by MRC, and the first correction graphic and the second correction graphic, adjust the position of the j new correction segments.

4. The optical proximity effect correction method according to claim 1, characterized in that, j=2i; or The re-segmentation involves dividing each of the i-th correction segments into two new correction segments.

5. The optical proximity effect correction method according to any one of claims 1-4, characterized in that, The number of each i-th correction segment in each long side is greater than 0 and less than 4.

6. The optical proximity effect correction method according to claim 5, characterized in that, The number of the i-th correction segments in each long side is 2.

7. The optical proximity effect correction method according to claim 6, characterized in that, The j new correction segments in the mask pattern, from closest to furthest from the short side, include a first segment, a second segment, a third segment, and a fourth segment, with df11 > df12 > df22 > df21. df11 is the outward displacement distance of the first segment in the mask pattern relative to the mask design pattern, df12 is the outward displacement distance of the second segment in the mask pattern relative to the mask design pattern, df21 is the outward displacement distance of the third segment in the mask pattern relative to the mask design pattern, and df22 is the outward displacement distance of the fourth segment in the mask pattern relative to the mask design pattern.

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 1-7.

10. A computer program product, comprising a computer program, 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 1-7.

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