Optical proximity correction method, storage medium and terminal
By combining global and local correction techniques in optical proximity correction, the weakness edges of the target pattern are detected and adjusted, and the difficulties in improving product yield and process efficiency in the prior art are solved, and a more efficient optical proximity correction effect is achieved.
Patent Information
- Application Number
- CN202311804596.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-25
- Publication Date
- 2025-06-27
AI Technical Summary
The existing optical proximity correction technology has the challenge of improving product yield and process efficiency, and it is difficult to effectively reduce the impact on the global correction graph correction accuracy outside the local optical proximity correction area.
After the global optical proximity correction, the local correction auxiliary pattern adjacent to the weak edge of the target pattern is detected and marked and local optical proximity correction is performed, including segmentation processing and segmentation movement, to adjust the edge placement error of the target pattern.
This improves product yield, reduces the number of iterations of global optical proximity correction, improves process efficiency, and reduces the impact on global correction graphics correction accuracy.
Smart Images
Figure CN120215196A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor technology, and particularly to an optical proximity correction method, a storage medium, and a terminal. Background Art
[0002] Integrated circuit manufacturing technology is a complex process with rapid technological updates. A key parameter characterizing integrated circuit manufacturing technology is the minimum feature size, i.e., the critical dimension (CD). As the critical dimension shrinks, even down to the nanometer level, it is precisely due to the reduction of the critical dimension that it becomes possible to have millions of devices on each chip.
[0003] Lithography technology is the driving force for the development of integrated circuit manufacturing processes and is also one of the most complex technologies. Compared with other individual manufacturing technologies, the improvement of lithography technology is of great significance to the development of integrated circuits. Before the lithography process begins, first, the pattern needs to be copied onto a mask through a specific device, and then through a lithography device, light of a specific wavelength is used to copy the pattern structure on the mask onto the silicon wafer of the production chip. However, due to the reduction in the size of semiconductor devices, distortion will occur during the process of transferring the pattern to the silicon wafer. If this distortion phenomenon is not eliminated, it will lead to the failure of the entire manufacturing technology. Therefore, to solve the above problem, optical proximity correction (OPC) can be performed on the mask. The optical proximity correction method is to perform pre-treatment on the lithography mask before lithography and make pre-modifications so that the amount of modification compensation can exactly compensate for the optical proximity effect caused by the exposure system.
[0004] During the optical proximity correction process, in order to increase the contrast of the pattern, usually a target pattern and sub-resolution assist patterns (scattering bars, sbar) are formed on the mask. Among them, the assist patterns are the surrounding patterns that produce optical proximity effects on the target pattern and do not form on the wafer after exposure. The assist patterns usually adopt rectangular strip patterns.
[0005] However, there are still many problems in the optical proximity correction of the prior art. Summary of the Invention
[0006] The technical problem solved by the present invention is to provide an optical proximity correction method, a storage medium, and a terminal, which can improve the product yield and the process efficiency and reduce the influence on the correction accuracy of the global correction pattern outside the local optical proximity correction area.
[0007] To solve the above technical problems, the technical solution of the present invention provides an optical proximity correction method, including: providing a target layout, the target layout having a plurality of target patterns; forming a plurality of auxiliary patterns, the plurality of auxiliary patterns surrounding each of the target patterns; performing global optical proximity correction on the target layout to obtain global correction patterns of each of the target patterns; after the global optical proximity correction, obtaining exposure patterns of each of the global correction patterns; comparing each of the target patterns with the corresponding exposure pattern to detect weak edges of the target patterns with positive edge placement errors exceeding a preset error range, and marking local correction auxiliary patterns to be locally optically proximity corrected in the auxiliary patterns adjacent to the weak edges, projecting along a direction perpendicular to the weak edges, and the weak edges having projection line segments on the edge contours of the local correction auxiliary patterns; performing the local optical proximity correction on the local correction auxiliary patterns; wherein, the local optical proximity correction includes: segmenting the local correction auxiliary pattern to make the edge placement error of the target pattern having the weak edge within the preset error range; wherein, the segmentation process includes: dividing and moving the local correction auxiliary pattern to form a first part pattern and a second part pattern, and there is a segmentation spacing dimension between the first part pattern and the second part pattern along the extending direction of the weak edge.
[0008] Optionally, the method of the segmentation process includes: cutting the local correction auxiliary pattern along a direction perpendicular to the weak edge to form an initial first part pattern and an initial second part pattern, the initial first part pattern having a first edge, the initial second part pattern having a second edge, and the first edge coinciding with the second edge; performing displacement processing on the initial first part pattern and the initial second part pattern to form the first part pattern and the second part pattern.
[0009] Optionally, the method of the displacement processing includes: translating the first edge in a direction away from the initial second part pattern; after the translation of the first edge, hermetically closing the third edge and the fourth edge perpendicular and opposite to the first edge in the initial first part pattern with the first edge respectively to form the closed first part pattern; translating the second edge in a direction away from the initial first part pattern; after the translation of the second edge, hermetically closing the fifth edge and the sixth edge perpendicular and opposite to the second edge in the initial second part pattern with the second edge respectively to form the closed second part pattern.
[0010] Optionally, the translation dimension of the first edge is equal to the translation dimension of the second edge.
[0011] Optionally, the segmentation spacing dimension is greater than or equal to the design rule spacing dimension between edges.
[0012] Optionally, along a direction perpendicular to the weak point edge, the cutting line of the local correction auxiliary figure and the midpoint of the weak point edge are located on the same straight line.
[0013] Optionally, after the segmentation process, it further includes: detecting the areas of the first figure and the second figure; when the area of the first figure and / or the second figure is less than the design rule area, performing an expansion process on the first figure and / or the second figure so that the area of the first figure and / or the second figure is greater than or equal to the design rule area.
[0014] Optionally, the method for performing the expansion process on the first figure includes: translating the seventh side opposite to the first side in the first figure in a direction away from the second figure; adaptively enclosing the third side and the fourth side in the first figure with the seventh side respectively to form a closed figure.
[0015] Optionally, the method for performing the expansion process on the second figure includes: translating the eighth side opposite to the second side in the second figure in a direction away from the first figure; adaptively enclosing the fifth side and the sixth side in the second figure with the eighth side respectively to form a closed figure.
[0016] Correspondingly, the technical solution of the present invention also provides a storage medium, on which computer instructions are stored, and when the computer instructions run, they execute the steps of the method described in any one of the above technical solutions.
[0017] Correspondingly, the technical solution of the present invention also provides a terminal, including a memory and a processor, where computer instructions capable of running on the processor are stored on the memory, and when the processor runs the computer instructions, it executes the steps of the method described in any one of the above technical solutions.
[0018] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:
[0019] In the optical proximity correction method provided by the technical solution of the present invention, after the global optical proximity correction based on the model, local correction auxiliary patterns adjacent to the weak edges are detected and marked, and the local optical proximity correction based on rules is performed on the local correction auxiliary patterns, so that the edge placement error of the target pattern having the weak edges is within a preset error range, thereby improving the product yield. By combining the global optical proximity correction and the local optical proximity correction, the number of iterations of the global optical proximity correction can be effectively reduced, the process efficiency can be improved, and the influence on the correction accuracy of the global correction pattern outside the local optical proximity correction region can be reduced. In addition, during the local optical proximity correction process, only the associated local correction auxiliary patterns are adjusted, rather than the global correction pattern corresponding to the edge placement error exceeding the preset error range, further reducing the influence on the correction accuracy of the global correction pattern outside the local optical proximity correction region.
[0020] Further, along the direction perpendicular to the weak edge, the cutting line of the local correction auxiliary pattern and the midpoint of the weak edge are on the same straight line. Since one of the evaluation points of the edge placement error of the global correction pattern is the midpoint of the weak edge, by dividing the local correction pattern from the position corresponding to the midpoint of the weak edge, the edge placement error of the target pattern can be adjusted most quickly. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 and Figure 2 are schematic structural diagrams of the steps of an optical proximity correction method;
[0022] Figure 3 is a flowchart of the optical proximity correction method according to an embodiment of the present invention;
[0023] Figures 4 to 9 are schematic structural diagrams of the steps of the optical proximity correction method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0024] As described in the background art, there are still many problems in the optical proximity correction of the prior art. The following will be specifically described with reference to the drawings.
[0025] Figure 1 and Figure 2 A schematic structural diagram of the process of an optical proximity correction method.
[0026] Please refer to Figure 1 , a target layout 100 is provided, and the target layout 100 has a plurality of target patterns 101; a plurality of auxiliary patterns 102 are formed, and the plurality of auxiliary patterns 102 surround each of the target patterns 101.
[0027] Please refer to Figure 2 to perform global optical proximity correction on the target layout 100 to obtain global corrected patterns (not shown) of each of the target patterns 101; after the global optical proximity correction, obtain the exposed patterns 103 of each of the global corrected patterns; compare each of the target patterns 101 with the corresponding exposed pattern 103 to obtain the edge placement error of each of the target patterns 101.
[0028] After the global optical proximity correction process, there will be some target patterns 101 whose edge placement errors exceed the preset error range. If we consider increasing the number of iterations of the global optical proximity correction to make the edge placement errors all within the preset error range, it will not only affect the process efficiency but also affect the correction accuracy of the global corrected patterns corresponding to the other edge placement errors within the preset error range. Moreover, during the process of increasing the number of iterations of the global optical proximity correction, the auxiliary patterns 102 do not participate in collaborative optimization together, but continuously adjust the problematic global corrected patterns, which will further increase the impact on the correction accuracy of the global corrected patterns around the problematic global corrected patterns.
[0029] To solve the above technical problems, the technical solution of the present invention provides an optical proximity correction method, a storage medium, and a terminal. After the global optical proximity correction based on a model, detect and mark local correction auxiliary patterns adjacent to the weak edges, and perform rule-based local optical proximity correction on the local correction auxiliary patterns, so that the edge placement error of the target pattern with the weak edge is within the preset error range, thereby improving the yield of the product. By combining the global optical proximity correction and the local optical proximity correction, it is possible to effectively reduce the number of iterations of the global optical proximity correction, improve the process efficiency, and reduce the impact on the correction accuracy of the global corrected patterns outside the local optical proximity correction area. In addition, during the local optical proximity correction process, only the associated local correction auxiliary patterns are adjusted, rather than the global corrected patterns corresponding to the edge placement errors exceeding the preset error range, further reducing the impact on the correction accuracy of the global corrected patterns outside the local optical proximity correction area.
[0030] To make the above objects, features, and beneficial effects of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given with reference to the accompanying drawings.
[0031] Figure 3 is a flowchart of the optical proximity correction method according to an embodiment of the present invention, including:
[0032] Step S101, provide a target layout, where the target layout has a number of target patterns;
[0033] Step S102, form a number of auxiliary patterns, and a number of the auxiliary patterns surround each of the target patterns;
[0034] Step S103, perform global optical proximity correction on the target layout to obtain global corrected patterns of each of the target patterns;
[0035] Step S104, after the global optical proximity correction, obtain exposure patterns of each of the global corrected patterns;
[0036] Step S105, compare each of the target patterns with the corresponding exposure pattern, detect weak edges of the target patterns whose edge placement errors are positive and exceed a preset error range, and mark local correction auxiliary patterns to be locally optically proximity corrected in the auxiliary patterns adjacent to the weak edges, and project along a direction perpendicular to the weak edges, and the weak edges have projection line segments on the edge contours of the local correction auxiliary patterns;
[0037] Step S106, perform the local optical proximity correction on the local correction auxiliary patterns; wherein, the local optical proximity correction includes: segmenting the local correction auxiliary patterns so that the edge placement errors of the target patterns having the weak edges are within the preset error range; wherein, the segmentation processing includes: dividing and moving the local correction auxiliary patterns to form a first part pattern and a second part pattern, and there is a segmentation spacing dimension between the first part pattern and the second part pattern along the extending direction of the weak edges.
[0038] The following will describe each step of the optical proximity correction method in detail with reference to the accompanying drawings.
[0039] Figures 4 to 9 It is a structural schematic diagram of each step of the specific process of the optical proximity correction method according to an embodiment of the present invention.
[0040] Please refer to Figure 4 , provide a target layout 200, where the target layout 200 has a number of target patterns 201.
[0041] It should be noted that each of the target patterns 201 in the target layout 200 is an initial pattern that has not undergone any optical proximity correction. Theoretically, in the absence of optical proximity effects, each of the target patterns 201 is the same as the corresponding exposure pattern obtained after subsequent exposure.
[0042] Please refer to Figure 5, a plurality of auxiliary patterns 202 are formed, and each of the target patterns 201 is surrounded by the plurality of auxiliary patterns 202.
[0043] It should be noted that, in the process of optical proximity correction, in order to increase the contrast of the patterns, the sub-resolution auxiliary patterns 202 are usually distributed around each of the target patterns 201, where the auxiliary patterns 202 are the surrounding patterns that generate optical proximity effects on the target patterns 201 and do not form on the wafer after exposure. The auxiliary patterns 202 usually adopt rectangular strip patterns.
[0044] Please refer to Figure 6 , perform global optical proximity correction on the target layout 200 to obtain the global corrected patterns 203 of each of the target patterns 201.
[0045] The global optical proximity correction is model-based optical proximity correction. For the target layout 200, all the target patterns 201 in the target layout 200 need to be subjected to optical proximity correction.
[0046] It should be noted that, in the process of the global optical proximity correction, only a small number of iteration times are required to make most of the global corrected patterns 203 converge (that is, the corresponding edge placement error is within the preset error range), while only a small number of the global corrected patterns 203 do not converge.
[0047] Please refer to Figure 7 , after the global optical proximity correction, obtain the exposure patterns 204 of each of the global corrected patterns 203.
[0048] The method for the exposure pattern 204 is obtained by simulating the exposure of each of the target patterns 201 after the global optical proximity correction.
[0049] Please continue to refer to Figure 7 , compare each of the target patterns 201 with the corresponding exposure pattern 204, detect the weak edges 201a of the target patterns 201 whose edge placement errors are positive and exceed the preset error range, and mark the local correction auxiliary patterns 205 to be locally optically proximity corrected in the auxiliary patterns 202 adjacent to the weak edges 201a, and project along the direction perpendicular to the weak edges 201a. The weak edges 201a have projection line segments on the edge contours of the local correction auxiliary patterns 205.
[0050] When the edge placement error of the target pattern 201 exceeds the preset error range, if it is applied to the actual manufacturing process, it will cause problems of pattern transfer distortion. Therefore, further processing is required to eliminate the pattern transfer distortion problem.
[0051] Please refer to Figure 8 and Figure 9 , Figure 9 is Figure 8 a magnified structural schematic diagram of part A in , and the local optical proximity correction includes: segmenting the local correction assist pattern 205 so that the edge placement error of the target pattern 201 having the weak edge 201a is within a preset error range.
[0052] Please continue to refer to Figure 8 and Figure 9 , and the segmentation process includes: dividing and moving the local correction assist pattern 205 to form a first part pattern 2051 and a second part pattern 2052, and there is a segmentation spacing dimension d between the first part pattern 2051 and the second part pattern 2052 along the extending direction of the weak edge 201a.
[0053] After the global optical proximity correction based on the model, the local correction assist pattern 205 adjacent to the weak edge 201a is detected and marked, and the local optical proximity correction based on rules is performed on the local correction assist pattern 205 so that the edge placement error of the target pattern 201 having the weak edge 201a is within a preset error range, thereby improving the product yield. By combining the global optical proximity correction and the local optical proximity correction, the iteration times of the global optical proximity correction can be effectively reduced, the process efficiency can be improved, and the influence on the correction accuracy of the global correction pattern 203 outside the local optical proximity correction area will be reduced. In addition, during the local optical proximity correction process, only the associated local correction assist pattern 205 is adjusted, rather than the global correction pattern 203 corresponding to the edge placement error exceeding the preset error range, further reducing the influence on the correction accuracy of the global correction pattern 203 outside the local optical proximity correction area.
[0054] Please continue to refer to Figure 8 and Figure 9 , and the method of the segmentation process includes: cutting the local correction assist pattern 205 along a direction perpendicular to the weak edge 201a to form an initial first part pattern and an initial second part pattern (not shown), the initial first part pattern has a first side L1, the initial second part pattern has a second side L2, and the first side L1 coincides with the second side L2; performing a displacement process on the initial first part pattern and the initial second part pattern to form the first part pattern 2051 and the second part pattern 2052.
[0055] Please continue to refer to Figure 8 and Figure 9, the method for displacement processing includes: translating the first side L1 in a direction away from the initial second part of the pattern; after the translation of the first side L1, hermetically closing the third side L3 and the fourth side L4 that are perpendicular and opposite to the first side L1 in the initial first part of the pattern with the first side L1 respectively to form the closed first part of the pattern 2051; translating the second side L2 in a direction away from the initial first part of the pattern; after the translation of the second side L2, hermetically closing the fifth side L5 and the sixth side L6 that are perpendicular and opposite to the second side L2 in the initial second part of the pattern with the second side L2 respectively to form the closed second part of the pattern 2052.
[0056] The translation dimension of the first side L1 is equal to the translation dimension of the second side L2, that is, the translation dimensions of both the first side L1 and the second side L2 are 1 / 2 of the segmentation spacing dimension d.
[0057] It should be noted that, in order to ensure that the spacing dimension between the first part of the pattern 2051 and the second part of the pattern 2052 after segmentation does not violate the Mask Rule Check (MRC), it is necessary that the segmentation spacing dimension d is greater than or equal to the designed rule spacing dimension between edges.
[0058] In this embodiment, along the direction perpendicular to the weak point edge 201a, the cutting line of the local correction auxiliary pattern 205 and the midpoint of the weak point edge 201a are on the same straight line. Since one of the evaluation points of the edge placement error of the global correction pattern 203 is the midpoint of the weak point edge 201a, by segmenting the local correction pattern from the position corresponding to the midpoint of the weak point edge 201a, the edge placement error of the target pattern 201 can be adjusted most quickly.
[0059] Please continue to refer to Figure 8 and Figure 9 , after the segmentation processing, it further includes: detecting the areas of the first part of the pattern 2051 and the second part of the pattern 2052; when the area of the first part of the pattern 2051 and / or the second part of the pattern 2052 is less than the designed rule area, performing an expansion process on the first part of the pattern 2051 and / or the second part of the pattern 2052 so that the area of the first part of the pattern 2051 and / or the second part of the pattern 2052 is greater than or equal to the designed rule area.
[0060] The purpose of the expansion process is also to ensure that the areas of the first part of the pattern 2051 and the second part of the pattern 2052 after segmentation do not violate the Mask Rule Check.
[0061] In this embodiment, the areas of the first graphic 2051 and the second graphic 2052 are both smaller than the design rule area. Therefore, the expansion process needs to be performed on both the first graphic 2051 and the second graphic 2052.
[0062] Please continue to refer to Figure 8 and Figure 9 , the method for performing the expansion process on the first graphic 2051 includes: translating the seventh side L7 opposite to the first side L1 in the first graphic 2051 in a direction away from the second graphic 2052; adaptively sealing the third side L3 and the fourth side L4 in the first graphic 2051 with the seventh side L7 respectively to form a closed graphic.
[0063] Please continue to refer to Figure 8 and Figure 9 , the method for performing the expansion process on the second graphic 2052 includes: translating the eighth side L8 opposite to the second side L2 in the second graphic 2052 in a direction away from the first graphic 2051; adaptively sealing the fifth side L5 and the sixth side L6 in the second graphic 2052 with the eighth side L8 respectively to form a closed graphic.
[0064] In other embodiments, when the areas of the first graphic and the second graphic are both larger than the design rule area, there is no need to perform the expansion process on the first graphic and the second graphic; when the area of one of the first graphic and the second graphic is smaller than the design rule area, only one of the first graphic and the second graphic needs to be subjected to the expansion process.
[0065] Correspondingly, an embodiment of the present invention also provides a storage medium, on which computer instructions are stored, and when the computer instructions run, they execute the steps of the method described in any one of the above embodiments.
[0066] Correspondingly, an embodiment of the present invention also provides a terminal, including a memory and a processor, where computer instructions capable of running on the processor are stored on the memory, and when the processor runs the computer instructions, it executes the steps of the method described in any one of the above embodiments.
[0067] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.
Claims
1. An optical proximity correction method, characterized in that Including: Providing a target layout, the target layout having a plurality of target patterns; Forming a plurality of auxiliary patterns, the plurality of auxiliary patterns surrounding each of the target patterns; Performing global optical proximity correction on the target layout to obtain global correction patterns of each of the target patterns; After the global optical proximity correction, obtaining exposure patterns of each of the global correction patterns; comparing each of the target patterns with the corresponding exposure pattern, detecting weak edges of the target patterns with positive edge placement errors exceeding a preset error range, and marking local correction auxiliary patterns to be locally optically proximally corrected in the auxiliary patterns adjacent to the weak edges, projecting along a direction perpendicular to the weak edge, and the weak edge having a projection line segment on the edge contour of the local correction auxiliary pattern; Performing the local optical proximity correction on the local correction auxiliary pattern; wherein, the local optical proximity correction includes: Segmenting the local correction auxiliary pattern so that the edge placement error of the target pattern having the weak edge is within a preset error range; Wherein, the segmentation processing includes: Segmenting and moving the local correction auxiliary pattern to form a first part pattern and a second part pattern, and there is a segmentation spacing dimension between the first part pattern and the second part pattern along the extending direction of the weak edge.
2. The optical proximity correction method according to claim 1, wherein The method of the segmentation processing includes: cutting the local correction auxiliary pattern along a direction perpendicular to the weak edge to form an initial first part pattern and an initial second part pattern, the initial first part pattern having a first side, the initial second part pattern having a second side, and the first side coinciding with the second side; performing displacement processing on the initial first part pattern and the initial second part pattern to form the first part pattern and the second part pattern.
3. The optical proximity correction method according to claim 2, wherein, The method of the displacement processing includes: translating the first side in a direction away from the initial second part pattern; after the first side is translated, hermetically closing the third side and the fourth side perpendicular and opposite to the first side in the initial first part pattern with the first side respectively to form the closed first part pattern; translating the second side in a direction away from the initial first part pattern; after the second side is translated, hermetically closing the fifth side and the sixth side perpendicular and opposite to the second side in the initial second part pattern with the second side respectively to form the closed second part pattern.
4. The optical proximity correction method according to claim 3, characterized in that The translation dimension of the first side is equal to the translation dimension of the second side.
5. The optical proximity correction method according to claim 1, characterized in that The segmentation spacing dimension is greater than or equal to the designed rule spacing dimension between edges.
6. The optical proximity correction method according to claim 2, characterized in that, Along a direction perpendicular to the weak edge, the cutting line of the local correction auxiliary pattern and the midpoint of the weak edge are on the same straight line.
7. The optical proximity correction method according to claim 3, wherein After the segmented processing, it further includes: detecting the areas of the first graphic and the second graphic; when the area of the first graphic and / or the second graphic is less than the design rule area, performing an expansion process on the first graphic and / or the second graphic so that the area of the first graphic and / or the second graphic is greater than or equal to the design rule area.
8. The optical proximity correction method according to claim 7, characterized in that The method for performing the expansion process on the first graphic includes: translating the seventh side opposite to the first side in the first graphic away from the second graphic; adaptively closing the third side and the fourth side in the first graphic with the seventh side respectively to form a closed graphic.
9. The optical proximity correction method according to claim 7, wherein The method for performing the expansion process on the second graphic includes: translating the eighth side opposite to the second side in the second graphic away from the first graphic; adaptively closing the fifth side and the sixth side in the second graphic with the eighth side respectively to form a closed graphic.
10. A storage medium, on which computer instructions are stored, characterized in that, When the computer instructions run, they execute the steps of the method according to any one of claims 1 to 9.
11. A terminal, comprising a memory and a processor, wherein computer instructions capable of running on the processor are stored on the memory, characterized in that When the processor runs the computer instructions, it executes the steps of the method according to any one of claims 1 to 9.