Optical proximity correction, photomask production and patterning method

Abstract

An optical proximity correction, photomask production and patterning method, wherein the optical proximity correction method comprises: respectively setting a first tolerance and a second tolerance for a first sub-pattern and a second sub-pattern in a first initial pattern, and the first tolerance is less than the second tolerance; performing optical proximity correction on the first initial pattern, and during the correction process, if the first edge placement error is less than or equal to the first tolerance, and the second edge placement error is less than or equal to the second tolerance, the optical proximity correction is completed, and a first corrected pattern is obtained. The optical proximity correction method provided by the present invention can improve the correction accuracy and correction efficiency.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to an optical proximity correction, photomask production and patterning method. Background Art

[0002] Photolithography is a crucial technology in semiconductor manufacturing technology. Photolithography can transfer patterns from the mask to the surface of the silicon wafer to form semiconductor products that meet the design requirements. The photolithography process includes an exposure step, a development step after the exposure step, and an etching step after the development step. In the exposure step, light is irradiated onto the silicon wafer coated with photoresist through the light-transmitting area in the mask, and the photoresist undergoes a chemical reaction under the irradiation of light; in the development step, the photolithography pattern is formed by utilizing the different degrees of solubility of the photosensitive and non-photosensitive photoresists in the developer, and the mask pattern is transferred to the photoresist; in the etching step, the silicon wafer is etched based on the photolithography pattern formed by the photoresist layer, and the mask pattern is further transferred to the silicon wafer.

[0003] In semiconductor manufacturing, as the design size continues to shrink, the design size is getting closer and closer to the limit of the lithography imaging system, and the diffraction effect of light becomes more and more obvious, resulting in optical image degradation of the design pattern. The actual lithography pattern is seriously distorted relative to the pattern on the mask. Finally, the actual pattern formed by lithography on the silicon wafer is different from the designed pattern. This phenomenon is called the optical proximity effect (OPE: Optical Proximity Effect).

[0004] In order to correct the optical proximity effect, optical proximity correction (OPC) was created. The core idea of ​​optical proximity correction is to establish an optical proximity correction model based on the consideration of offsetting the optical proximity effect, and design the photomask pattern according to the optical proximity correction model. In this way, although the optical proximity effect occurs in the photolithography pattern corresponding to the photomask pattern after photolithography, since the offset of this phenomenon has been considered when designing the photomask pattern according to the optical proximity correction model, the photolithography pattern after photolithography is close to the target pattern that the user actually wants to obtain.

[0005] However, the correction accuracy and correction efficiency of optical proximity correction in the prior art are relatively low. Summary of the invention

[0006] The technical problem solved by the present invention is to provide an optical proximity correction method, a photomask production and a patterning method to improve the correction accuracy and correction efficiency.

[0007] To solve the above technical problems, an embodiment of the present invention provides an optical proximity correction method, comprising: providing a first initial figure, wherein the first initial figure includes a first sub-figure and a second sub-figure; setting a first tolerance and a second tolerance for the first sub-figure and the second sub-figure, respectively, wherein the first tolerance is less than the second tolerance; performing simulated exposure on the first initial figure to obtain a first simulated figure and a second simulated figure corresponding to the first sub-figure and the second sub-figure, respectively; comparing the first simulated figure and the first sub-figure, and the second simulated figure and the second sub-figure, to obtain a first edge placement error and a second edge placement error; judging whether the first edge placement error is less than or equal to the first tolerance, and whether the second edge placement error is less than or equal to the second tolerance; if the judgment result is yes, the optical proximity correction is completed, and a first corrected figure is obtained; if the judgment result is no, adjusting the first sub-figure and the second sub-figure, and re-executing the above exposure and comparison steps until the optical proximity correction is completed, and a first corrected figure is obtained.

[0008] Optionally, it also includes: performing simulated exposure on the first corrected pattern to obtain a first corrected simulated pattern; adjusting the first corrected simulated pattern to obtain a second initial pattern; performing optical proximity correction on the second initial pattern m times to obtain a second corrected pattern, where m is a natural number greater than or equal to 1.

[0009] Optionally, the first corrected simulation graphic includes a first sub-corrected simulation graphic and a second sub-corrected simulation graphic, and the method for adjusting the first corrected simulation graphic includes: taking multiple sampling points on the first sub-graphic and the second sub-graphic, respectively, and determining corresponding positions of the multiple sampling points on the first sub-corrected simulation graphic and the second sub-corrected simulation graphic; comparing the position difference of the same sampling point in the first sub-graphic and the first sub-corrected simulation graphic, and the position difference between the second sub-graphic and the second sub-corrected simulation graphic, to obtain a third edge placement error and a fourth edge placement error; obtaining an average value of the third edge placement error as an average third edge placement error, and obtaining an average value of the fourth edge placement error as an average fourth edge placement error; adjusting the edges corresponding to the sampling points in the first sub-corrected simulation graphic based on the average third edge placement error; and adjusting the edges corresponding to the sampling points in the second sub-corrected simulation graphic based on the average fourth edge placement error.

[0010] Optionally, before performing optical proximity correction on the second initial graphic, a third tolerance is set for the second initial graphic, and the third tolerance is 0.

[0011] Optionally, the method for obtaining the first edge placement error and the second edge placement error includes: taking multiple sampling points on the first sub-graph and the second sub-graph, respectively, and determining corresponding positions of the multiple sampling points on the first simulation graph and the second simulation graph; comparing the position difference of the same sampling point in the first sub-graph and the first simulation graph to obtain the first edge placement error; comparing the position difference of the same sampling point in the second sub-graph and the second simulation graph to obtain the second edge placement error.

[0012] Optionally, the step of adjusting the first sub-graph includes: obtaining sampling points corresponding to edge placement errors greater than the first tolerance based on the difference between edge placement errors of different sampling points and the first tolerance, and adjusting the edges corresponding to the sampling points in the first sub-graph; the step of adjusting the second sub-graph includes: obtaining sampling points corresponding to edge placement errors greater than the second tolerance based on the difference between edge placement errors of different sampling points and the second tolerance, and adjusting the edges corresponding to the sampling points in the second sub-graph.

[0013] The present invention also provides a method for making a photomask, comprising: providing a first initial pattern, the first initial pattern comprising a first sub-pattern and a second sub-pattern; setting a first tolerance and a second tolerance for the first sub-pattern and the second sub-pattern, respectively, the first tolerance being less than the second tolerance; performing simulated exposure on the first initial pattern to obtain a first simulated pattern and a second simulated pattern corresponding to the first sub-pattern and the second sub-pattern, respectively; comparing the first simulated pattern and the first sub-pattern, the second simulated pattern and the second sub-pattern, to obtain a first edge placement error and a second edge placement error; judging whether the first edge placement error is less than or equal to the first tolerance, and whether the second edge placement error is less than or equal to the second tolerance; if the judgment result is yes, optical proximity correction is completed to obtain a first corrected pattern; if the judgment result is no, adjusting the first sub-pattern and the second sub-pattern, and re-performing the above-mentioned exposure and comparison steps until the optical proximity correction is completed to obtain a first corrected pattern; transferring the obtained first corrected pattern to the photomask to form a first mask pattern.

[0014] Optionally, after forming the first corrected pattern, it also includes: performing simulated exposure on the first corrected pattern to obtain a first corrected simulated pattern; adjusting the first corrected simulated pattern to obtain a second initial pattern; performing m optical proximity corrections on the second initial pattern to obtain a second corrected pattern, where m is a natural number greater than or equal to 1; and transferring the second corrected pattern to a photomask to form a second mask pattern.

[0015] The present invention also provides a patterning method, comprising: providing a first initial pattern, the first initial pattern including a first sub-pattern and a second sub-pattern; setting a first tolerance and a second tolerance for the first sub-pattern and the second sub-pattern, respectively, the first tolerance being less than the second tolerance; performing simulated exposure on the first initial pattern to obtain a first simulation pattern and a second simulation pattern corresponding to the first sub-pattern and the second sub-pattern, respectively; comparing the first simulation pattern and the first sub-pattern, the second simulation pattern and the second sub-pattern, to obtain a first edge placement error and a second edge placement error; judging whether the first edge placement error is less than or equal to the first tolerance, and whether the second edge placement error is less than or equal to the second tolerance; if the judgment result is yes, optical proximity correction is completed to obtain a first corrected pattern; if the judgment result is no, adjusting the first sub-pattern and the second sub-pattern, and re-performing the above-mentioned exposure and comparison steps until the optical proximity correction is completed to obtain a first corrected pattern; transferring the obtained first corrected pattern to a photomask to form a first mask pattern; transferring the first mask pattern to a wafer to form a first target pattern.

[0016] Optionally, after forming the first corrected pattern, it also includes: performing simulated exposure on the first corrected pattern to obtain a first corrected simulated pattern; adjusting the first corrected simulated pattern to obtain a second initial pattern; performing m optical proximity corrections on the second initial pattern to obtain a second corrected pattern, where m is a natural number greater than or equal to 1; transferring the second corrected pattern to a photomask to form a second mask pattern; and transferring the second mask pattern to a wafer to form a second target pattern.

[0017] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0018] In the optical proximity correction method provided by the present invention, the first initial graphic includes a first sub-graphic and a second sub-graphic, and a first tolerance and a second tolerance are set for the first sub-graphic and the second sub-graphic, respectively, and the first tolerance is smaller than the second tolerance. When optical proximity correction is performed on the first initial graphic having different correction accuracy requirements for the first sub-graphic and the second sub-graphic, as long as the first edge placement error and the second edge placement error satisfy the corresponding first tolerance and second tolerance, respectively, the optical proximity correction can be completed. When the first sub-graphic cannot be repaired in place, due to the setting of the second tolerance, and the second tolerance is greater than the first tolerance, the second sub-graphic can automatically adjust the graphic within the second tolerance range, providing space for the correction of the first sub-graphic so that the first sub-graphic can meet the repair requirements. On the one hand, the correction accuracy of the first sub-graphic can be improved, and on the other hand, there is no need to exit the optical proximity correction to change the second sub-graphic, which can improve the correction efficiency.

[0019] Further, the first correction pattern is simulated exposed to obtain a first correction simulation pattern; the first correction simulation pattern is adjusted to obtain a second initial pattern, and then the second initial pattern is subjected to m optical proximity corrections. The first correction simulation pattern is adjusted to obtain a second initial pattern with a better pattern shape, and after the second initial pattern is subjected to m optical proximity corrections, the convergence of the second initial pattern can be enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figures 1 to 5 is a schematic diagram of an optical proximity correction process in a first embodiment of the present invention;

[0021] Figures 6 to 9 FIG. 4 is a schematic diagram of an optical proximity correction process in a second embodiment of the present invention. DETAILED DESCRIPTION

[0022] At present, when performing optical proximity correction (OPC) on some design graphics, it is often the case that the graphics are not repaired to the target size after reaching the predetermined number of iterations. At this time, the graphics accuracy obtained after OPC is relatively poor. If you want to make the graphics reach the target size, especially some key graphics with high importance, if the importance of the adjacent graphics is relatively low, the design target of the adjacent graphics will be changed at this time. This method is called target preprocessing. The target preprocessing technology is to manually correct the hotspot after running a round of OPC to find the hotspot, and then perform OPC on the corrected graphics. Repeated debugging will eventually reach the desired target graphics.

[0023] Target preprocessing requires human intervention for correction. Before the next round of OPC, new design graphics need to be defined in advance. After running OPC and viewing the results, the next round of processing can be carried out. Since the new design graphics defined in advance are not necessarily optimal, this process requires repeated debugging to achieve the ideal result, which is not conducive to improving the efficiency of OPC.

[0024] In order to solve the above problems, the inventor provides an optical proximity correction method, which sets a first tolerance and a second tolerance for the first sub-graphic and the second sub-graphic in the first initial graphic, respectively, and the first tolerance is less than the second tolerance. In the process of optical proximity correction of the first sub-graphic and the second sub-graphic, when the first sub-graphic cannot be corrected to the target size, due to the existence of the second tolerance, the second sub-graphic can be automatically changed under the condition of meeting the second tolerance requirement, providing sufficient space for the correction of the first sub-graphic, until both the first sub-graphic and the second sub-graphic meet the correction requirements, that is, the first edge placement error is less than or equal to the first tolerance, and the second edge placement error is less than or equal to the second tolerance, and the optical proximity correction is completed. The optical proximity correction method can automatically adjust the first initial graphic within the tolerance range, without exiting the optical proximity correction to manually modify the first initial graphic, so that the first initial graphic can reach the target size, improving the correction accuracy and the correction efficiency.

[0025] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0026] First embodiment

[0027] Figures 1 to 5 is a schematic diagram of the optical proximity correction process in the first embodiment of the present invention, wherein: Figure 1 is a flow chart of the optical proximity correction process in the first embodiment.

[0028] First, step S10 is executed to provide a first initial graphic.

[0029] refer to Figure 2 , the first initial graphic 100 includes a first sub-graphic 110 and a second sub-graphic 120.

[0030] It should be noted that the first sub-graph 110 and the second sub-graph 120 refer to a type of graph, and the number may be one or more. The first sub-graph 110 refers to a key graph of high importance in the semiconductor manufacturing process, such as a graph corresponding to a device located in an active area of ​​a semiconductor; the second sub-graph 120 refers to a general graph of low importance, such as a graph corresponding to a device located in an inactive area.

[0031] The first initial pattern 100 is a target of optical proximity correction, that is, in an ideal state, the pattern on the wafer is consistent with the first initial pattern 100 .

[0032] In this embodiment, the number of the first sub-graph 110 and the number of the second sub-graph 120 are one.

[0033] In this embodiment, the first sub-graph 110 and the second sub-graph 120 are both long strip structures. For the convenience of subsequent description, a line segment in the first sub-graph 110 is set as graph A, and a line segment in the second sub-graph 120 opposite to graph A is set as graph B, wherein graph A is a key graph of high importance, and graph B is a general graph of low importance.

[0034] In this embodiment, the optical proximity correction is performed mainly by taking the pattern A in the first sub-pattern 110 and the pattern B in the second sub-pattern 120 as examples.

[0035] Continue to refer Figure 1 , executing step S20, setting a first tolerance and a second tolerance for the first sub-graph 110 and the second sub-graph 120 respectively.

[0036] The first tolerance is smaller than the second tolerance, that is, the first tolerance given to the key graphic A with high importance is smaller than the second tolerance given to the general graphic B with low importance.

[0037] In this embodiment, the first tolerance refers to the range of the first edge placement error (EPE) that can be accepted by the first sub-pattern 110 in the subsequent optical proximity correction process. As long as the first edge placement error is within this range, it can be considered that the correction of the first sub-pattern 110 meets the requirements and the optical proximity correction can be terminated. Similarly, the second tolerance refers to the range of the second edge placement error that can be accepted by the second sub-pattern 120 in the subsequent optical proximity correction process.

[0038] The first tolerance being smaller than the second tolerance means that an acceptable range of first edge placement error is smaller than an acceptable range of second edge placement error.

[0039] In this embodiment, the first tolerance is set to 0 nm, and the second tolerance is set to + / - 2 nm.

[0040] The specific values ​​of the first tolerance and the second tolerance need to be determined in the actual manufacturing process according to the requirements of the graphics for accuracy. If the graphics have high requirements for accuracy, the tolerance is set to be smaller; conversely, if the graphics have low requirements for accuracy, the tolerance can be set to be larger.

[0041] In this embodiment, the first tolerance and the second tolerance are manually set. After the corresponding tolerance is manually determined according to the accuracy requirements of the graphics, the determined tolerance values ​​are input into the computer performing the OPC operation.

[0042] In this embodiment, the first tolerance is smaller than the second tolerance because in the semiconductor manufacturing process, the key graphics with high importance generally have high precision requirements, and in the optical proximity correction process, the key graphics need to be repaired to the target size as much as possible, so the first tolerance is set to be lower.

[0043] In this embodiment, the setting of the second tolerance can enable the second sub-graphic 120 to automatically adjust the graphic during the optical proximity correction process without manually changing the second sub-graphic, and can provide space for the correction of the first sub-graphic until the optical correction is completed. On the one hand, it improves the correction accuracy of the first sub-graphic, and on the other hand, it also improves the OPC correction efficiency.

[0044] Execute step S30 to perform simulated exposure on the first initial pattern.

[0045] refer to Figure 3 After the first initial pattern 100 is subjected to simulated exposure, a first simulated pattern 111 and a second simulated pattern 121 corresponding to the first sub-pattern 110 and the second sub-pattern 120 are obtained.

[0046] In this embodiment, the first simulation graphic 111 and the second simulation graphic 121 are obtained by a simulation method.

[0047] Step S40 is executed to compare the first simulation graphic 111 and the first sub-graphic 110 , and the second simulation graphic 121 and the second sub-graphic 120 , to obtain a first edge placement error and a second edge placement error.

[0048] The specific steps of obtaining the first edge placement error and the second edge placement error include:

[0049] refer to Figure 4 , multiple sampling points are taken on the first sub-graph 110 and the second sub-graph 120 respectively.

[0050] In this embodiment, sampling points are specifically taken on the graph A and the graph B. The sampling points on the graph A include A1, A2, and A3, and the sampling points on the graph B include B1, B2, and B3.

[0051] Corresponding positions of the plurality of sampling points are determined on the first simulation graph 111 and the second simulation graph 121 .

[0052] Specifically, for the sampling point A1 set on the first sub-graph 110 graph A, the extending direction at the sampling point A1 is a first direction (X direction) and a second direction (Y direction) perpendicular to the first direction (X direction), and the point intersecting with the first simulation graph 111 in the second direction is the corresponding position a1 of the sampling point A1.

[0053] In this embodiment, the corresponding positions of A1, A2, A3 are determined as a1, a2, a3 on the first simulation graphic 111, and the corresponding positions of B1, B2, B3 are determined as b1, b2, b3 on the second simulation graphic 121.

[0054] The position difference of the same sampling point in the first sub-graph 110 and the first simulation graph 111 is compared to obtain a first edge placement error.

[0055] In this embodiment, the first edge placement error obtained includes the position difference EPE between A1 and a1 A1 , the position difference between A2 and a2 EPE A2 , the position difference between A3 and a3 EPE A3 .

[0056] The position difference of the same sampling point in the second sub-graph 120 and the second simulation graph 121 is compared to obtain a second edge placement error.

[0057] In this embodiment, the second edge placement error obtained includes the position difference EPE between B1 and b1 B1 , the position difference EPE between B2 and b2 B2 , the position difference EPE between B3 and b3 B3 .

[0058] Execute step S50 to determine whether the first edge placement error is less than or equal to the first tolerance, and whether the second edge placement error is less than or equal to the second tolerance.

[0059] In this embodiment, specifically, the first edge placement error EPE is determined A1 、EPE A2 and EPE A3 Is it less than or equal to the first tolerance, and determine the second edge placement error EPE B1 、EPE B2 and EPE B3 Is it less than or equal to the second tolerance?

[0060] If the judgment result is yes, step S60 is executed, the optical proximity correction is completed, and the first correction pattern 200 is obtained.

[0061] Figure 5 is a schematic diagram of the first correction graph 200 .

[0062] In this embodiment, EPE is required A1 、EPE A2 and EPE A3 are both less than or equal to the first tolerance, it is considered that the first edge placement error is less than or equal to the first tolerance; similarly, EPE is required B1 、EPE B2 and EPE B3 are both less than or equal to the second tolerance, it is considered that the second edge placement error is less than or equal to the second tolerance.

[0063] If the judgment result is no, step S70 is executed to adjust the first initial graphic 100, that is, adjust the first sub-graphic 110 and / or the second sub-graphic 120 to reduce the edge placement error.

[0064] When the judgment result is no, the step of adjusting the first sub-graph 110 includes: obtaining the positions of sampling points corresponding to edge placement errors greater than the first tolerance according to the difference between edge placement errors of different sampling points and the first tolerance, and adjusting the sides corresponding to the sampling points in the first sub-graph 110 according to the positions of the sampling points; the step of adjusting the second sub-graph 120 includes: obtaining the positions of sampling points corresponding to edge placement errors greater than the second tolerance according to the difference between edge placement errors of different sampling points and the second tolerance, and adjusting the sides corresponding to the sampling points in the second sub-graph according to the positions of the sampling points.

[0065] In this embodiment, it is assumed that the first edge placement error is EPE A1 If the value is greater than the first tolerance, the position of the sampling point A1 is determined, and the side corresponding to the sampling point A1 in the first character pattern is adjusted according to the position of the sampling point A1, so as to reduce the edge placement error.

[0066] If the first edge placement error is greater than the first tolerance, adjust the first sub-graph 110; if the second edge placement error is greater than the second tolerance, adjust the second sub-graph 120; if the first edge placement error is greater than the first tolerance and the second edge placement error is greater than the second tolerance, adjust the first sub-graph 110 and the second sub-graph 120.

[0067] After adjusting the first sub-pattern 110 and / or the second sub-pattern 120 , steps S30 to S50 are re-executed until the optical proximity correction is completed, and the first corrected pattern 200 is obtained.

[0068] Taking the adjustment of the first sub-graph 110 as an example, the adjusted first sub-graph 110 is simulated exposed to obtain a first adjustment simulation graph corresponding to the adjusted first sub-graph; the first adjustment simulation graph and the adjusted first sub-graph are compared to obtain a first edge placement error, and the method for obtaining the first edge placement error is the same as mentioned above and will not be repeated here; if the first edge placement error is less than or equal to the first tolerance, the optical proximity correction is completed; if the first edge placement error is greater than the first tolerance, continue to adjust the first sub-graph, and re-execute the above steps until the first edge placement error is less than or equal to the first tolerance, the optical proximity correction is completed, and the first corrected graph 200 is obtained.

[0069] The schematic diagram of the first correction graph 200 is shown in FIG. Figure 5 .

[0070] In this embodiment, a first tolerance is set for the first sub-graph 110, i.e., a key graph of high importance, and a second tolerance is set for the second sub-graph 120, i.e., a general graph of relatively low importance. Since the key graph has a high requirement for correction accuracy, the first tolerance is smaller than the second tolerance. In the actual optical proximity correction process, since the correction requirement for the first sub-graph is high, it may happen that the correction requirement cannot be met after reaching the preset number of iterations. In this case, the second tolerance is set to automatically change the second sub-graph adjacent to the first sub-graph. Within the range of the second tolerance, the distance between the first and second sub-graphs can be expanded, providing sufficient space for the correction of the first sub-graph, so that the first sub-graph can continue to be corrected until the correction requirement is met. Therefore, the correction accuracy of the first sub-graph, i.e., the key graph, is improved. In addition, the general graph adjacent to the key graph is automatically changed, and there is no need to exit the optical proximity correction and make changes manually, thereby improving the correction efficiency.

[0071] The first embodiment of the present invention further provides a method for manufacturing a photomask, wherein the first correction pattern 200 obtained by the optical proximity correction method is transferred to the photomask to form a first mask pattern.

[0072] The first embodiment of the present invention further provides a patterning method, which transfers the first mask pattern obtained above to a wafer to form a first target pattern.

[0073] Second embodiment

[0074] Figures 6 to 9 is a schematic diagram of optical proximity correction in the second embodiment of the present invention, wherein: Figure 6 is a flow chart of optical proximity correction in the second embodiment of the present invention.

[0075] In this embodiment, the steps of obtaining the first correction graph 200 are the same as those in the first embodiment, and will not be repeated here.

[0076] After obtaining the first correction graph 200, refer to Figure 6 , execute step S100, perform simulated exposure on the first corrected pattern 200 to obtain a first corrected simulated pattern 210.

[0077] Figure 7 is a schematic diagram of the first corrected simulation graph 210 .

[0078] In this embodiment, the first correction simulation graph 210 includes a first sub-correction simulation graph 211 and a second sub-correction simulation graph 212. The first sub-correction simulation graph 211 has a graph A' corresponding to the graph A, and the second sub-correction simulation graph 212 has a graph B' corresponding to the graph B.

[0079] Continue to refer Figure 6 , execute step S200, adjust the first corrected simulation graph 210, and obtain the second initial graph 300.

[0080] Figure 8 is a schematic diagram of the second initial graphic 300, wherein the second initial graphic 300 has a graphic A" and a graphic B" corresponding to the graphic A' and the graphic B', respectively.

[0081] In this embodiment, the method for adjusting the first corrected simulation graphic 210 includes: taking multiple sampling points on the first sub-graphic 110 and the second sub-graphic 120 respectively, and determining the corresponding positions of the multiple sampling points on the first sub-corrected simulation graphic 211 and the second sub-corrected simulation graphic 212; comparing the position difference of the same sampling point in the first sub-graphic 110 and the first sub-corrected simulation graphic 211, and the position difference between the second sub-graphic 120 and the second sub-corrected simulation graphic 212, to obtain a third edge placement error and a fourth edge placement error; obtaining an average value of the third edge placement error as an average third edge placement error, and obtaining an average value of the fourth edge placement error as an average fourth edge placement error; adjusting the edges corresponding to the sampling points in the first sub-corrected simulation graphic 211 based on the average third edge placement error; and adjusting the edges corresponding to the sampling points in the second sub-corrected simulation graphic 212 based on the average fourth edge placement error.

[0082] In this embodiment, taking the average third edge placement error as a reference means that the edge placement error corresponding to each sampling point in the first sub-corrected simulation pattern 211 is equal to the value of the average third edge placement error.

[0083] In other embodiments, the maximum value or the minimum value of the third edge placement error and the fourth edge placement error may be selected as a reference to adjust the edge corresponding to the sampling point in the first corrected simulation graph 210 to obtain the second initial graph 300.

[0084] Depend on Figure 7 It can be seen that in the first corrected simulation graph 210, the graphs A' and B' are relatively rough and the line segments are uneven. Therefore, by adjusting the graphs A' and B' to form graphs A" and B" with smoother line segments, the convergence of the second initial graph 300 is enhanced.

[0085] Continue to refer Figure 6 , executing step S400, performing m (m is a natural number greater than or equal to 1) optical proximity corrections on the second initial graphic 300.

[0086] It should be noted that, before executing step S400 , step S300 is also executed to set a third tolerance for the second initial graphic 300 .

[0087] In this embodiment, the third tolerance is set to 0. This is because, due to the setting of the first tolerance and the second tolerance, there may be a certain range of errors in the process of performing optical proximity correction on the first sub-graph 110 and the second sub-graph 120, so that in the obtained first correction simulation graph 210, the first sub-correction simulation graph 211 and the second sub-correction simulation graph 212 are more friendly than the initial first sub-graph 110 and the second sub-graph 120, that is, the graph B' is in a position that enables the graph A' to meet the repair requirements. When performing subsequent optical proximity correction, it is not necessary to set a larger tolerance to achieve the purpose of correction of the second initial graph, and the tolerance is set to 0 to ensure the correction accuracy of the second initial graph 300.

[0088] In this embodiment, the step of performing m (m is a natural number greater than or equal to 1) optical proximity corrections on the second initial pattern 300 is the same as that in the first embodiment, and is also achieved by simulated exposure, comparison and other methods, which will not be repeated here.

[0089] Finally, step S500 is executed to obtain the second corrected graph 400 .

[0090] Fig. 9 is a schematic diagram of the second correction graph 400 .

[0091] The second embodiment of the present invention further provides a method for manufacturing a photomask, wherein the second correction pattern 400 obtained by the optical proximity correction method is transferred to the photomask to form a second mask pattern.

[0092] The second embodiment of the present invention further provides a patterning method, which transfers the second mask pattern obtained above to a wafer to form a second target pattern.

[0093] 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 shall be subject to the scope defined by the claims.

Claims

1. An optical proximity correction method, characterized in that: include: Providing a first initial graphic, wherein the first initial graphic includes a first sub-graphic and a second sub-graphic; Setting a first tolerance and a second tolerance for the first sub-graph and the second sub-graph respectively, wherein the first tolerance is smaller than the second tolerance; Performing simulated exposure on the first initial pattern to obtain a first simulated pattern and a second simulated pattern corresponding to the first sub-pattern and the second sub-pattern respectively; Taking a plurality of sampling points on the first sub-graph and the second sub-graph respectively, and determining corresponding positions of the plurality of sampling points on the first simulation graph and the second simulation graph; Comparing the position difference of the same sampling point in the first sub-graph and the first simulation graph to obtain a first edge placement error; Compare the position difference of the same sampling point in the second sub-graph and the second simulation graph to obtain a second edge placement error; Determining whether the first edge placement error is less than or equal to the first tolerance, and whether the second edge placement error is less than or equal to the second tolerance; If the judgment result is yes, the optical proximity correction is completed and a first correction pattern is obtained; If the judgment result is no, adjusting the first sub-pattern and / or the second sub-pattern, and re-performing the above-mentioned exposure and comparison steps until the optical proximity correction is completed to obtain a first corrected pattern; Among them, the step of adjusting the first sub-graph includes: obtaining the positions of sampling points corresponding to edge placement errors greater than the first tolerance according to the difference between edge placement errors of different sampling points and the first tolerance, and adjusting the edges corresponding to the sampling points in the first sub-graph according to the positions of the sampling points; the step of adjusting the second sub-graph includes: obtaining the positions of sampling points corresponding to edge placement errors greater than the second tolerance according to the difference between edge placement errors of different sampling points and the second tolerance, and adjusting the edges corresponding to the sampling points in the second sub-graph according to the positions of the sampling points.

2. The optical proximity correction method according to claim 1, wherein: Also includes: Performing simulated exposure on the first correction pattern to obtain a first correction simulation pattern; Adjusting the first corrected simulation graph to obtain a second initial graph; Performing optical proximity correction m times on the second initial pattern to obtain a second corrected pattern, where m is a natural number greater than or equal to 1.

3. The optical proximity correction method according to claim 2, wherein: The first correction simulation pattern includes a first sub-correction simulation pattern and a second sub-correction simulation pattern, and the method for adjusting the first correction simulation pattern includes: Taking a plurality of sampling points on the first sub-graph and the second sub-graph respectively, and determining corresponding positions of the plurality of sampling points on the first sub-corrected simulation graph and the second sub-corrected simulation graph; Compare the position difference of the same sampling point in the first sub-pattern and the first sub-corrected simulation pattern, and the position difference of the second sub-pattern and the second sub-corrected simulation pattern, to obtain a third edge placement error and a fourth edge placement error; Obtaining an average value of the third edge placement errors as an average third edge placement error, and obtaining an average value of the fourth edge placement errors as an average fourth edge placement error; Based on the average third edge placement error, adjusting the edge corresponding to the sampling point in the first sub-corrected simulation graph; The edges corresponding to the sampling points in the second sub-corrected simulation graph are adjusted based on the average fourth edge placement error.

4. The optical proximity correction method according to claim 2, wherein: Before performing optical proximity correction on the second initial graphic, a third tolerance is set for the second initial graphic, and the third tolerance is 0.

5. A method for making a photomask, characterized in that: include: Providing a first initial graphic, wherein the first initial graphic includes a first sub-graphic and a second sub-graphic; Setting a first tolerance and a second tolerance for the first sub-graph and the second sub-graph respectively, wherein the first tolerance is smaller than the second tolerance; Performing simulated exposure on the first initial pattern to obtain a first simulated pattern and a second simulated pattern corresponding to the first sub-pattern and the second sub-pattern respectively; Taking a plurality of sampling points on the first sub-graph and the second sub-graph respectively, and determining corresponding positions of the plurality of sampling points on the first simulation graph and the second simulation graph; Comparing the position difference of the same sampling point in the first sub-graph and the first simulation graph to obtain a first edge placement error; Compare the position difference of the same sampling point in the second sub-graph and the second simulation graph to obtain a second edge placement error; determine whether the first edge placement error is less than or equal to the first tolerance, and whether the second edge placement error is less than or equal to the second tolerance; If the judgment result is yes, the optical proximity correction is completed and a first correction pattern is obtained; If the judgment result is no, adjusting the first sub-pattern and the second sub-pattern, and re-performing the above-mentioned exposure and comparison steps until the optical proximity correction is completed to obtain a first corrected pattern; The step of adjusting the first sub-graph comprises: obtaining the positions of sampling points corresponding to edge placement errors greater than the first tolerance according to the difference between edge placement errors of different sampling points and the first tolerance, and adjusting the edges corresponding to the sampling points in the first sub-graph according to the positions of the sampling points; the step of adjusting the second sub-graph comprises: obtaining the positions of sampling points corresponding to edge placement errors greater than the second tolerance according to the difference between edge placement errors of different sampling points and the second tolerance, and adjusting the edges corresponding to the sampling points in the second sub-graph according to the positions of the sampling points; The obtained first correction pattern is transferred to a photomask to form a first mask pattern.

6. The method for manufacturing a photomask according to claim 5, wherein: After forming the first correction graph, the method further comprises: Performing simulated exposure on the first correction pattern to obtain a first correction simulation pattern; Adjusting the first corrected simulation graph to obtain a second initial graph; Performing m optical proximity corrections on the second initial pattern to obtain a second corrected pattern, where m is a natural number greater than or equal to 1; The second correction pattern is transferred to a photomask to form a second mask pattern.

7. A graphical method, characterized in that: include: Providing a first initial graphic, wherein the first initial graphic includes a first sub-graphic and a second sub-graphic; Setting a first tolerance and a second tolerance for the first sub-graph and the second sub-graph respectively, wherein the first tolerance is smaller than the second tolerance; Performing simulated exposure on the first initial pattern to obtain a first simulated pattern and a second simulated pattern corresponding to the first sub-pattern and the second sub-pattern respectively; Taking a plurality of sampling points on the first sub-graph and the second sub-graph respectively, and determining corresponding positions of the plurality of sampling points on the first simulation graph and the second simulation graph; Comparing the position difference of the same sampling point in the first sub-graph and the first simulation graph to obtain a first edge placement error; Compare the position difference of the same sampling point in the second sub-graph and the second simulation graph to obtain the second edge placement error Determining whether the first edge placement error is less than or equal to the first tolerance, and whether the second edge placement error is less than or equal to the second tolerance; If the judgment result is yes, the optical proximity correction is completed and a first correction pattern is obtained; If the judgment result is no, adjusting the first sub-pattern and the second sub-pattern, and re-performing the above-mentioned exposure and comparison steps until the optical proximity correction is completed to obtain a first corrected pattern; The step of adjusting the first sub-graph comprises: obtaining the positions of sampling points corresponding to edge placement errors greater than the first tolerance according to the difference between edge placement errors of different sampling points and the first tolerance, and adjusting the edges corresponding to the sampling points in the first sub-graph according to the positions of the sampling points; the step of adjusting the second sub-graph comprises: obtaining the positions of sampling points corresponding to edge placement errors greater than the second tolerance according to the difference between edge placement errors of different sampling points and the second tolerance, and adjusting the edges corresponding to the sampling points in the second sub-graph according to the positions of the sampling points; Transferring the obtained first correction pattern to a photomask to form a first mask pattern; The first mask pattern is transferred to a wafer to form a first target pattern.

8. The graphical method according to claim 7, characterized in that: After obtaining the first revised graph, the method further includes: Performing simulated exposure on the first correction pattern to obtain a first correction simulation pattern; Adjusting the first corrected simulation graph to obtain a second initial graph; Performing m optical proximity corrections on the second initial pattern to obtain a second corrected pattern, where m is a natural number greater than or equal to 1; transferring the second correction pattern to a photomask to form a second mask pattern; The second mask pattern is transferred to the wafer to form a second target pattern.

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