Optical proximity effect correction method
By adjusting the position or line segment of the sub-resolution auxiliary pattern in the manufacturing of integrated circuits, the problem of excessive edge placement error in the contact hole layout is solved, the process window is expanded, and the reliability of the lithography process is improved.
Patent Information
- Application Number
- CN202510898347.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-30
- Publication Date
- 2025-08-12
AI Technical Summary
During the integrated circuit manufacturing process, in the optical proximity effect correction of the contact hole layout, the edge placement error between the target pattern and the simulated pattern is too large or the risk of connecting the process window is small.
By obtaining the edge placement error between the target graphics and the simulated graphics, comparing with preset feature values, determining the segment to be corrected, and moving the sub-resolution auxiliary graphics or some of its line segments to adjust the edge placement error.
The edge placement error between the target graphics and the simulated graphics is improved, the process window is expanded, and the reliability of the lithography process is improved.
Smart Images
Figure CN120469147A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of integrated circuits, and in particular to a method for correcting an optical proximity effect. Background Art
[0002] During semiconductor device manufacturing, when the critical dimensions of an integrated circuit are reduced to a level comparable to the exposure wavelength of the lithography equipment, an optical proximity effect (OPE) occurs. This phenomenon is caused by the diffraction and interference of light through the mask during light propagation, resulting in deformation and distortion of the integrated circuit structure pattern when it is copied from the mask to the photoresist during the lithography process. To overcome the optical proximity effect, an optical proximity correction (OPC) method is typically used to pre-modify the lithography mask that is expected to deform and distort, so that the amount of modification compensation is just enough to compensate for the optical proximity effect generated by the lithography machine exposure system, thereby ensuring that the final exposure pattern on the silicon wafer is consistent with the target pattern. However, when performing OPC correction on the contact hole layout, if the contact hole pattern correction is limited, there is a risk of excessive edge placement error or pinching between the target pattern and the simulation pattern, resulting in a smaller process window. Summary of the Invention
[0003] The object of the present invention is to provide an optical proximity effect correction method to solve the problem of excessive edge placement error or connection line.
[0004] To solve the above technical problems, the present invention provides an optical proximity effect correction method, comprising:
[0005] Providing a contact hole layout, wherein the contact hole layout has a plurality of target patterns and a plurality of simulation patterns, the target patterns corresponding to the simulation patterns one-to-one, and a plurality of sub-resolution auxiliary patterns formed around the target patterns;
[0006] Obtaining edge placement errors between all the target graphics and the corresponding simulation graphics;
[0007] Comparing the edge placement errors of all the target graphics with a preset characteristic value to obtain the segments to be corrected in all the target graphics according to the comparison results;
[0008] determining a sub-resolution auxiliary graphic to be corrected among all the sub-resolution auxiliary graphics based on the segment to be corrected;
[0009] The sub-resolution auxiliary pattern to be corrected is moved or some line segments in the sub-resolution auxiliary pattern to be corrected are moved to adjust the edge placement error.
[0010] Optionally, in the optical proximity effect correction method, the sub-resolution pattern to be corrected is the sub-resolution auxiliary pattern within a preset distance in a vertical direction of the segment to be corrected.
[0011] Optionally, in the optical proximity effect correction method, if the ratio between the edge placement error and the preset characteristic value is equal to a preset threshold, the sub-resolution auxiliary graphic to be corrected is moved; if the ratio between the edge placement error and the preset characteristic value is less than the preset threshold, part of the line segments in the sub-resolution auxiliary graphic to be corrected is moved.
[0012] Optionally, in the optical proximity effect correction method, the method of moving the sub-resolution auxiliary pattern to be corrected includes:
[0013] Presetting the moving direction of the sub-resolution auxiliary graphic to be corrected;
[0014] The sub-resolution auxiliary pattern to be corrected is moved according to a preset moving direction of the sub-resolution auxiliary pattern to be corrected.
[0015] Optionally, in the optical proximity effect correction method, the method of presetting the moving direction of the sub-resolution auxiliary pattern to be corrected includes:
[0016] If the edge placement error is positive, the sub-resolution auxiliary pattern to be corrected is moved away from the segment to be corrected; if the edge placement error is negative, the sub-resolution auxiliary pattern to be corrected is moved toward the segment to be corrected.
[0017] Optionally, in the optical proximity effect correction method, after moving the sub-resolution auxiliary pattern to be corrected, the method further includes:
[0018] Obtaining the adjusted edge placement error;
[0019] It is determined whether the adjusted edge placement error is less than the preset characteristic value; if not, some line segments in the sub-resolution auxiliary graphic to be corrected are moved until the adjusted edge placement error is less than the preset characteristic value.
[0020] Optionally, in the optical proximity effect correction method, the method of moving some line segments in the sub-resolution auxiliary pattern to be corrected includes:
[0021] Step 1: dividing the edge of the sub-resolution auxiliary graphic to be corrected close to the segment to be corrected into multiple line segments, and obtaining a local line segment to be corrected from all the line segments, and aligning the local line segment to be corrected with the segment to be corrected;
[0022] Step 2: preset the moving direction of the local line segment to be corrected;
[0023] Step three: moving the local line segment to be corrected according to a preset moving direction of the local line segment to be corrected.
[0024] Optionally, in the optical proximity effect correction method, after moving the local line segment to be corrected, the method further includes:
[0025] Obtaining the adjusted edge placement error value;
[0026] It is determined whether the adjusted edge placement error is less than the preset characteristic value; if not, the local line segment to be corrected is continuously moved until the adjusted edge placement error is less than the preset characteristic value.
[0027] Optionally, in the optical proximity effect correction method, if the edge placement error is a positive value, the local line segment to be corrected is moved away from the fragment to be corrected; if the edge placement error is a negative value, the local line segment to be corrected is moved toward the fragment to be corrected.
[0028] Optionally, in the optical proximity effect correction method, the length of the local line segment to be corrected is greater than the width of the target pattern.
[0029] In the optical proximity effect correction method provided by the present invention, the edge placement errors between all target patterns and corresponding simulation patterns are first obtained. The edge placement errors of all target patterns are then compared with a preset characteristic value to obtain, based on the comparison results, segments to be corrected within all target patterns. Next, sub-resolution auxiliary patterns to be corrected within all sub-resolution auxiliary patterns are determined based on the segments to be corrected. Finally, the sub-resolution auxiliary patterns to be corrected, or segments within the sub-resolution auxiliary patterns to be corrected, are moved to adjust the edge placement errors. This improves the edge placement errors between the target patterns and the corresponding simulation patterns, thereby improving the process window. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figures 1 and 2 1 is a flow chart of a method for correcting an optical proximity effect provided by an embodiment of the present invention;
[0031] Figures 3 to 7 Schematic diagram of a layout structure formed in each step of the optical proximity effect correction method provided by an embodiment of the present invention;
[0032] The description of the accompanying drawings is as follows:
[0033] 100 - contact hole pattern; 110 - target pattern; 111 - segment to be corrected; 120 - original pattern; 120a - OPC pattern; 130 - sub-resolution auxiliary pattern; 131 - sub-resolution auxiliary pattern to be corrected; 131a - local line segment to be corrected; 140 - simulation pattern. DETAILED DESCRIPTION
[0034] The optical proximity effect correction method proposed in the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer based on the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structures shown in the drawings are often part of the actual structure. In particular, each drawing needs to show different focuses, and sometimes different proportions are used.
[0035] Figure 1 FIG. 1 is a flow chart of a method for correcting an optical proximity effect according to an embodiment of the present invention. Figure 1 As shown, the optical proximity effect correction method provided in this embodiment includes:
[0036] Step S1: providing a contact hole layout, wherein the contact hole layout has a plurality of target patterns and a plurality of simulation patterns, wherein the target patterns correspond to the simulation patterns in a one-to-one manner, and a plurality of sub-resolution auxiliary patterns are formed around the target patterns;
[0037] Step S2: Obtaining edge placement errors between all the target graphics and the corresponding simulation graphics;
[0038] Step S3: comparing the edge placement errors of all the target graphics with a preset characteristic value, so as to obtain the segments to be corrected in all the target graphics according to the comparison results;
[0039] Step S4: determining a sub-resolution auxiliary graphic to be corrected among all the sub-resolution auxiliary graphics based on the segment to be corrected;
[0040] Step S5: moving the sub-resolution auxiliary pattern to be corrected or moving some line segments in the sub-resolution auxiliary pattern to be corrected to adjust the edge placement error.
[0041] Figures 3 to 7 This is a schematic diagram of the layout structure formed in each step of the optical proximity effect correction method provided by the embodiment of the present invention; Figures 3 to 7 The optical proximity effect correction method provided in this embodiment is described in more detail.
[0042] First, execute step S1, as Figure 3As shown, a contact hole layout 100 is provided. The contact hole layout 100 has a plurality of target patterns 110 and a plurality of simulation patterns 140 . The target patterns 110 correspond to the simulation patterns 140 one by one. A plurality of sub-resolution auxiliary patterns 130 are formed around the target patterns 110 .
[0043] Specifically, when forming the target pattern 110 and the OPC pattern 120 a , the target pattern 110 and the OPC pattern 120 a may be formed according to a preset design rule, and then a sub-resolution auxiliary pattern (sbar) 130 may be filled between adjacent target patterns 110 .
[0044] The OPC pattern 120a is formed by correcting the original pattern (Input) 120 for the optical proximity effect. The original pattern 120 is the original design pattern and may be a contact hole pattern used to form contact holes during the actual semiconductor device manufacturing process. Furthermore, a photolithography simulation model can be used to adjust the OPC pattern 120a through repeated iterative calculations to reduce the error between the OPC pattern 120a and the target pattern 110.
[0045] In addition, a simulation graphic 140 is also formed in the contact hole layout 100. The simulation graphic 140 is a process simulation graphic of the OPC graphic, that is, the simulation graphic 140 is based on the OPC graphic and predicts the graphic deformation or defect formation that may occur in actual manufacturing by simulating the photolithography process and etching process steps.
[0046] Next, step S2 is executed to obtain edge placement errors between all the target graphics 110 and the corresponding simulation graphics 140 .
[0047] Then, execute step S3, as Figure 4 As shown, the edge placement errors of all the target graphics 110 are compared with the preset characteristic values, so as to obtain the to-be-corrected segments 111 in all the target graphics 110 according to the comparison results.
[0048] In this embodiment, the method for obtaining the segments 111 to be corrected from all target graphics 110 includes: determining the target graphics to be corrected from all target graphics based on the magnitude relationship between the edge placement error of the target graphics 110 and a preset characteristic value. If the edge placement error of the target graphics 110 is less than the preset characteristic value, the edge placement error of the target graphics 110 meets the requirement; otherwise, it does not meet the requirement. That is, if the edge placement error of the target graphics 110 is greater than or equal to the preset characteristic value, the target graphics 110 is determined to be a target graphics to be corrected, and a segment (a side of the target graphics to be corrected) that does not meet the edge placement requirement is selected from the target graphics to be corrected as the segment 111 to be corrected.
[0049] That is to say, if Figure 2 As shown, the method for obtaining all the segments 111 to be corrected in the target graphic 110 includes:
[0050] Step S31, determine whether the edge placement error meets the requirements, if not, execute step S32;
[0051] Step S32: Obtain all segments to be corrected in the target graphics.
[0052] Then, if Figure 4 As shown, step S4 is executed to determine the sub-resolution auxiliary graphics 131 to be corrected among all the sub-resolution auxiliary graphics based on the segment to be corrected, that is, to obtain the sub-resolution auxiliary graphics 131 to be corrected.
[0053] Specifically, the sub-resolution pattern to be corrected is the sub-resolution auxiliary pattern within a preset distance in the vertical direction of the segment to be corrected.
[0054] Next, step S5 is executed to move the sub-resolution auxiliary graphic to be corrected or move some line segments in the sub-resolution auxiliary graphic to be corrected to adjust the edge placement error to avoid the risk of excessive edge placement error or pinching between the target graphic and the simulation graphic 140.
[0055] In some embodiments, if the ratio between the edge placement error and the predetermined characteristic value is equal to a predetermined threshold, the sub-resolution auxiliary pattern 131 to be corrected is moved.
[0056] In some embodiments, if the ratio of the edge placement error to the preset characteristic value is smaller than the preset threshold, some line segments in the sub-resolution auxiliary pattern to be corrected are moved.
[0057] Specifically, the method of moving the sub-resolution auxiliary graphic to be corrected or moving some line segments in the sub-resolution auxiliary graphic to be corrected includes:
[0058] Step S51 , determining whether the proportional relationship between the edge placement error and the preset characteristic value is equal to a preset threshold.
[0059] If yes, then execute step S52, as Figure 5 As shown, if the ratio between the edge placement error and the preset characteristic value is equal to a preset threshold, the sub-resolution auxiliary pattern 131 to be corrected is moved.
[0060] Among them, if the edge placement error is a positive value, the preset threshold is (1+M%)*A. When the ratio between the edge placement error and the preset characteristic value is equal to the preset threshold, the edge placement error and the preset characteristic value satisfy the following relationship:
[0061] EPE=(1+M%)*A; wherein EPE represents the edge placement error, A represents the preset characteristic value, and M is greater than or equal to 100.
[0062] If the edge placement error is a negative value, the preset threshold is -(1+M%)*A. When the ratio between the edge placement error and the preset characteristic value is equal to the preset threshold, the edge placement error and the preset characteristic value satisfy the following relationship:
[0063] EPE=-(1+M%)*A; wherein EPE represents the edge placement error, A represents the preset characteristic value, and M is greater than or equal to 100.
[0064] In this embodiment, the method of moving the sub-resolution auxiliary pattern to be corrected 131 includes:
[0065] First, if Figure 5 As shown, the movement direction of the sub-resolution auxiliary pattern 131 to be corrected is preset. Specifically, if the edge placement error is a positive value, the sub-resolution auxiliary pattern 131 to be corrected is moved in a direction Y2 away from the segment 111 to be corrected, i.e., the distance between the sub-resolution auxiliary pattern 131 to be corrected and the segment 111 to be corrected is increased, thereby increasing the distance between the sub-resolution auxiliary pattern 131 to be corrected and the OPC pattern. If the edge placement error is a negative value, the sub-resolution auxiliary pattern 131 to be corrected is moved in a direction Y1 toward the segment 111 to be corrected, i.e., the distance between the sub-resolution auxiliary pattern 131 to be corrected and the segment 111 to be corrected is increased.
[0066] Then, the sub-resolution auxiliary pattern 131 to be corrected is moved according to the preset moving direction of the sub-resolution auxiliary pattern 131 to be corrected, thereby improving the edge placement error between the target pattern 110 and the corresponding simulation pattern 14 and improving the process window.
[0067] Specifically, if the edge placement error is positive, the partial line segment 131a to be corrected is moved in the direction Y2 away from the target pattern by a distance of (1+M%)A*B. If the edge placement error is negative, the partial line segment 131a to be corrected is moved in the direction Y1 toward the target pattern by a distance of (1+M%)A*B. Here, A represents the preset characteristic value; B represents the adjustment coefficient, and B<0, M≥100.
[0068] Furthermore, after moving the sub-resolution auxiliary graphic 131 to be corrected, the process also includes: executing step S53: determining whether the edge placement error meets the requirements (ie, whether the edge placement error is less than a preset characteristic value); if so, executing step S6; if not, executing step S54.
[0069] In particular, if the ratio between the edge placement error and the preset characteristic value is less than the preset threshold, step S54 is executed to move some line segments in the sub-resolution auxiliary graphic 131 to be corrected to adjust the edge placement error. That is to say, when the edge placement error is less than M% worse than the characteristic value, or after moving the sub-resolution auxiliary graphic 131 to be corrected, the edge placement error still does not meet the requirement, it is necessary to segment one side of the sub-resolution auxiliary graphic 131 to be corrected according to the placement relationship between the sub-resolution auxiliary graphic 131 to be corrected and the target graphic 110, and adjust the specified line segments after segmentation, so as to improve the edge placement error between the target graphic 110 and the corresponding simulation graphic 140.
[0070] Specifically, the method of moving some line segments in the sub-resolution auxiliary graphic 131 to be corrected includes:
[0071] Step 1, such as Figure 6 As shown, the edge of the sub-resolution auxiliary graphic 131 to be corrected close to the fragment 111 to be corrected is divided into multiple line segments, and a local line segment 131a to be corrected is obtained from all the line segments, and the local line segment 131a to be corrected is aligned with the fragment 111 to be corrected; wherein, the length of the local line segment 131a to be corrected is greater than the width W of the target graphic 110.
[0072] Step 2: Preset the moving direction of the local line segment 131a to be corrected; specifically, if the edge placement error is a positive value, move the local line segment 131a to be corrected in the direction Y2 away from the segment 111 to be corrected, that is, expand the edge of the local line segment 131a to be corrected; if the edge placement error is a negative value, move the local line segment 131a to be corrected in the direction Y1 close to the segment 111 to be corrected, that is, retreat the edge of the local line segment 131a to be corrected.
[0073] Step 3: Move the partial line segment 131a according to the preset moving direction of the partial line segment 131a. The moving distance can be A*B, where A represents the preset characteristic value, B represents the adjustment coefficient, and B<0. If the edge placement error is a negative value, move the partial line segment 131a in the direction Y1 closer to the segment 111 to be corrected by a moving distance of A*B, where A represents the preset characteristic value, B represents the adjustment coefficient, and B<0.
[0074] In this embodiment, after moving the local line segment 131a to be corrected, Figure 2 As shown, it also includes: obtaining the edge placement error value between the adjusted target graphic and the simulation graphic; then, judging whether the adjusted edge placement error is less than the preset characteristic value, that is, after executing step S54, executing step S53 to judge whether the adjusted edge placement error value meets the requirement (whether it is less than the preset characteristic value); if not, continuing to execute step S54, that is, continuing to move the local line segment 131a to be corrected until the adjusted edge placement error is less than the preset characteristic value, so as to improve the edge placement error between the target graphic and the corresponding simulation graphic, so that the edge placement error meets the requirement and the process window is improved; if so, that is, the adjusted edge placement error value meets the requirement (less than the preset characteristic value), executing step S6 to perform hotspot verification on the corrected contact hole layout 100, that is, the sub-resolution graphic in the contact hole layout 100 is corrected to form a new OPC layout (that is, the corrected contact hole layout 100), and hotspot verification is performed on the new OPC layout. After the hotspot verification, the OPC corrected layout data is output.
[0075] In summary, the optical proximity effect correction method provided by the embodiments of the present invention first obtains the edge placement errors between all target patterns and their corresponding simulation patterns. The edge placement errors of all target patterns are then compared with preset characteristic values to determine the segments to be corrected within all target patterns based on the comparison results. Next, the sub-resolution auxiliary patterns to be corrected within all sub-resolution auxiliary patterns are determined based on the segments to be corrected. Finally, the sub-resolution auxiliary patterns to be corrected, or portions of the line segments within the sub-resolution auxiliary patterns to be corrected, are moved to adjust the edge placement errors. This improves the edge placement errors between the target patterns and their corresponding simulation patterns, thereby improving the process window.
[0076] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other. In addition, the different parts between the various embodiments can also be used in combination with each other, and the present invention is not limited to this.
[0077] The above description is only a description of the preferred embodiments of the present invention and does not limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.
Claims
1. A method for correcting an optical proximity effect, characterized in that: include: Providing a contact hole layout, wherein the contact hole layout has a plurality of target patterns and a plurality of simulation patterns, the target patterns corresponding to the simulation patterns one-to-one, and a plurality of sub-resolution auxiliary patterns formed around the target patterns; Obtaining edge placement errors between all the target graphics and the corresponding simulation graphics; Comparing the edge placement errors of all the target graphics with a preset characteristic value to obtain the segments to be corrected in all the target graphics according to the comparison results; determining a sub-resolution auxiliary graphic to be corrected among all the sub-resolution auxiliary graphics based on the segment to be corrected; The sub-resolution auxiliary pattern to be corrected is moved or some line segments in the sub-resolution auxiliary pattern to be corrected are moved to adjust the edge placement error.
2. The optical proximity effect correction method according to claim 1, wherein: The sub-resolution pattern to be corrected is the sub-resolution auxiliary pattern within a preset distance in the vertical direction of the segment to be corrected.
3. The optical proximity effect correction method according to claim 1, wherein: If the ratio between the edge placement error and the preset characteristic value is equal to a preset threshold, moving the sub-resolution auxiliary pattern to be corrected; If the ratio of the edge placement error to the preset characteristic value is smaller than the preset threshold, some line segments in the sub-resolution auxiliary graphic to be corrected are moved.
4. The optical proximity effect correction method according to claim 1, wherein: The method for moving the sub-resolution auxiliary graphic to be corrected includes: Presetting the moving direction of the sub-resolution auxiliary graphic to be corrected; The sub-resolution auxiliary pattern to be corrected is moved according to a preset moving direction of the sub-resolution auxiliary pattern to be corrected.
5. The optical proximity effect correction method according to claim 4, wherein: The method for presetting the moving direction of the sub-resolution auxiliary graphic to be corrected includes: If the edge placement error is positive, the sub-resolution auxiliary pattern to be corrected is moved away from the segment to be corrected; if the edge placement error is negative, the sub-resolution auxiliary pattern to be corrected is moved toward the segment to be corrected.
6. The optical proximity effect correction method according to claim 4, wherein: After moving the sub-resolution auxiliary graphic to be corrected, the method further includes: Obtaining the adjusted edge placement error; It is determined whether the adjusted edge placement error is less than the preset characteristic value; if not, some line segments in the sub-resolution auxiliary graphic to be corrected are moved until the adjusted edge placement error is less than the preset characteristic value.
7. The optical proximity effect correction method according to claim 1 or 6, wherein: The method for moving some line segments in the sub-resolution auxiliary graphic to be corrected includes: Step 1: dividing the edge of the sub-resolution auxiliary graphic to be corrected close to the segment to be corrected into multiple line segments, and obtaining a local line segment to be corrected from all the line segments, and aligning the local line segment to be corrected with the segment to be corrected; Step 2: preset the moving direction of the local line segment to be corrected; Step three: moving the local line segment to be corrected according to a preset moving direction of the local line segment to be corrected.
8. The optical proximity effect correction method according to claim 7, wherein: After moving the local line segment to be corrected, the method further includes: Obtaining the adjusted edge placement error value; It is determined whether the adjusted edge placement error is less than the preset characteristic value; if not, the local line segment to be corrected is continuously moved until the adjusted edge placement error is less than the preset characteristic value.
9. The method for correcting proximity effect according to claim 8, wherein: If the edge placement error is a positive value, the local line segment to be corrected is moved in a direction away from the segment to be corrected; if the edge placement error is a negative value, the local line segment to be corrected is moved in a direction close to the segment to be corrected.
10. The optical proximity effect correction method according to claim 1, wherein: The length of the local line segment to be corrected is greater than the width of the target graphic.