Optical proximity correction method

Abstract

An optical proximity correction method comprises: segmenting a first target edge of a first target pattern into a plurality of first segments with a first length, and segmenting a second target edge of a second target pattern into a plurality of second segments with a second length; providing an optical proximity correction model, and performing optical proximity correction on the first target pattern and the second target pattern a plurality of times, wherein before each optical proximity correction, the first length of the plurality of first segments is adjusted, and the second length of the plurality of second segments is adjusted, until the first edge placement error and the second edge placement error are both within a preset edge placement error range. By cyclically traversing the optical proximity correction of the plurality of first segments and the plurality of second segments under different length combinations, the first edge placement error under the size limitation of the mask is well solved without moving the adjacent edges.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to an optical proximity correction method. Background Technology

[0002] Photolithography is a crucial technology in semiconductor manufacturing. It transfers patterns from a photomask to the surface of a silicon wafer, forming semiconductor products that meet design requirements. The photolithography process includes an exposure step, a development step following exposure, and an etching step following development. In the exposure step, light passes through the light-transmitting areas of the photomask and shines onto the silicon wafer coated with photoresist, causing a chemical reaction in the photoresist. In the development step, the different solubility of the developer in the photoresist and the non-photoresist is used to form a photolithographic pattern, transferring the photomask pattern onto the photoresist. In the etching step, the silicon wafer is etched based on the photolithographic pattern formed by the photoresist layer, further transferring the photomask pattern onto the silicon wafer.

[0003] In semiconductor manufacturing, as design dimensions continue to shrink and approach the limits of photolithography imaging systems, the diffraction effect of light becomes increasingly pronounced, leading to optical image degradation of the final design pattern. The actual photolithographic pattern formed is severely distorted relative to the pattern on the mask, resulting in a difference between the actual pattern formed on the silicon wafer and the design pattern. This phenomenon is called the Optical Proximity Effect (OPE).

[0004] To correct the optical proximity effect, Optical Proximity Correction (OPC) was developed. The core idea of ​​OPC is to establish an OPC model based on the consideration of counteracting the optical proximity effect. The photomask pattern is designed according to the OPC model. In this way, although the lithographic pattern and the corresponding photomask pattern have an optical proximity effect, the cancellation of this phenomenon has been considered when designing the photomask pattern according to the OPC model. Therefore, the lithographic pattern after photolithography is close to the target pattern actually desired by the user.

[0005] However, existing optical proximity correction technologies still have many problems. Summary of the Invention

[0006] The technical problem solved by this invention is to provide an optical proximity correction method to improve correction accuracy and efficiency.

[0007] To solve the above technical problems, the present invention provides an optical proximity correction method, comprising: acquiring a first correction pattern, the first correction pattern including a first correction graphic and a second correction graphic, the first correction graphic including a first correction edge, the second correction graphic including a second correction edge, the first correction edge and the second correction edge being adjacent and parallel, the first correction edge and the second correction edge having a first spacing dimension, and the first spacing dimension being equal to the mask regularity dimension; performing a first exposure processing on the first correction pattern to acquire a first exposure pattern, the first exposure pattern including a first exposure graphic and a second exposure graphic, the first exposure graphic including a first exposure edge corresponding to the first correction edge, the second exposure graphic including a second exposure edge corresponding to the second correction edge; providing a target pattern, the target pattern including a first target graphic and a second target graphic, the first target graphic surrounding the first exposure graphic, the first target graphic including a first target edge corresponding to the first exposure edge, the second target graphic surrounding the second exposure graphic, the second target graphic including a second target edge corresponding to the second exposure edge; acquiring the first correction pattern... The system includes: a first edge placement error between the exposure edge and the first target edge, and a second edge placement error between the second exposure edge and the second target edge; a preset edge placement error range is provided, wherein the first edge placement error is greater than the preset edge placement error range, and the second edge placement error is within the preset edge placement error range; the system performs segmentation processing on the first target image and the second target image, wherein the segmentation processing includes dividing the first target edge of the first target image into several first segments, each of which has a first length dimension, and dividing the second target edge of the second target image into several second segments, each of which has a second length dimension; an optical proximity correction model is provided, wherein the segmented first target image and the second target image are subjected to several optical proximity corrections according to the optical proximity correction model, and before each optical proximity correction, the first length dimensions of several first segments and the second length dimensions of several second segments are adjusted until both the first edge placement error and the second edge placement error are within the preset edge placement error range.

[0008] Optionally, the first target edge of the first target graphic is divided into two first segmentation segments.

[0009] Optionally, the method of adjusting the first length dimension of the plurality of first segments before each optical proximity correction includes: before performing the first optical proximity correction, the first length dimension of the plurality of first segments is the first length dimension after segmenting the first target image; before each optical proximity correction after performing the first optical proximity correction, the first length dimension of one of the first segments is increased by a step length dimension, and the first length dimension of the other first segment is decreased by the step length dimension.

[0010] Optionally, the length dimension of the first step is in the range of 0.5nm to 1.5nm.

[0011] Optionally, the second target edge of the second target graphic is divided into two second segmentation segments.

[0012] Optionally, the method of adjusting the second length dimensions of the plurality of second segments before each optical proximity correction includes: before performing the first optical proximity correction, the second length dimensions of the plurality of second segments are the second length dimensions after segmenting the second target image; before each optical proximity correction after performing the first optical proximity correction, the second length dimension of one of the second segments is increased by a second step size, and the second length dimension of the other second segment is decreased by a second step size.

[0013] Optionally, the range of the second step size is 0.5nm to 1.5nm.

[0014] Optionally, before each optical proximity correction, before adjusting the first length dimension of the plurality of first segments and the second length dimension of the plurality of second segments, the method further includes: providing a regular length dimension, wherein the first length dimension and the second length dimension are greater than or equal to the regular length dimension.

[0015] Optionally, before segmenting the first target graphic and the second target graphic, the method further includes: marking the first target edge of the first target graphic and the second target edge of the second target graphic.

[0016] Optionally, the method for obtaining the first corrected layout includes: providing an initial layout, the initial layout including a first graphic and a second graphic, the first graphic including a first side, the second graphic including a second side, the first side and the second side being adjacent and parallel; performing initial optical proximity correction on the initial layout to obtain the first corrected layout, wherein the first corrected side corresponds to the first side and the second corrected side corresponds to the second side.

[0017] Optionally, the method for obtaining the first edge placement error includes: obtaining a first sampling point of the first exposure edge; obtaining a second sampling point of the first target edge; obtaining a second distance dimension between the first sampling point and the second sampling point, and using the second distance dimension as the first edge placement error.

[0018] Optionally, the method for obtaining the second edge placement error includes: obtaining a third sampling point of the second exposure edge; obtaining a fourth sampling point of the second target edge; obtaining a third distance dimension between the third sampling point and the fourth sampling point, and using the third distance dimension as the second edge placement error.

[0019] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects:

[0020] The optical proximity correction method provided by the present invention performs several optical proximity corrections on the segmented first target graphic and second target graphic according to the optical proximity correction model. Before each optical proximity correction, the first length dimensions of several first segmented segments and the second length dimensions of several second segmented segments are adjusted until both the first edge placement error and the second edge placement error are within the preset edge placement error range. By iteratively traversing the optical proximity corrections of several first segmented segments and several second segmented segments under different length dimension combinations, the final moving layout result is fundamentally intervened. Without moving adjacent edges, it has a good effect on solving the first edge placement error under the mask rule size constraint, thereby improving correction accuracy and correction efficiency. Attached Figure Description

[0021] Figures 1 to 3 A schematic diagram of the process structure of an optical proximity correction method;

[0022] Figure 4 This is a flowchart of the optical proximity correction method according to an embodiment of the present invention;

[0023] Figures 5 to 11 This is a schematic diagram of the specific steps of the optical proximity correction method according to an embodiment of the present invention. Detailed Implementation

[0024] As described in the background section, existing optical proximity correction techniques still have many problems. These will be explained in detail below with reference to the accompanying drawings.

[0025] Figures 1 to 3 A schematic diagram of the process structure of an optical proximity correction method.

[0026] Please refer to Figure 1 A first corrected pattern is obtained, which includes a first corrected pattern 1001 and a second corrected pattern 1002. The first corrected pattern 1001 includes a first corrected edge 1001a, and the second corrected pattern 1002 includes a second corrected edge 1002a. The first corrected edge 1001a and the second corrected edge 1002a are adjacent and parallel. There is a first spacing dimension d1 between the first corrected edge 1001a and the second corrected edge 1002a, and the first spacing dimension d1 is equal to the mask rule dimension dr.

[0027] Please refer to Figure 2 The first exposure pattern is obtained by performing a first exposure process on the first corrected pattern. The first exposure pattern includes a first exposure pattern 1011 and a second exposure pattern 1012. The first exposure pattern 10111 includes a first exposure edge 1011a corresponding to the first corrected edge 1001a, and the second exposure pattern 1012 includes a second exposure edge 1012a corresponding to the second corrected edge 1002a.

[0028] Please refer to Figure 3 The system provides a target layout, which includes a first target graphic 1021 and a second target graphic 1022. The first target graphic 1021 surrounds the first exposure graphic 1011 and includes a first target edge 1021a corresponding to the first exposure edge 1011a. The second target graphic 1022 surrounds the second exposure graphic 1012 and includes a second target edge 1022a corresponding to the second exposure edge 1012a. The system also acquires a first edge placement error EPE1 between the first exposure edge 1011a and the first target edge 1021a, and a second edge placement error EPE2 between the second exposure edge 1012a and the second target edge 1022a. Finally, it provides a preset edge placement error range EPE. spec The first edge placement error EPE1 is greater than the preset edge placement error range EPE. spec The second edge placement error EPE2 is within the preset edge placement error range EPE. spec Inside.

[0029] In this embodiment, since the first edge placement error EPE1 is greater than the preset edge placement error range EPE spec This results in the final graphic size not meeting design requirements. Therefore, the first correction edge 1001a needs to be translated to reduce the first edge placement error EPE1 to the preset edge placement error range EPE. specHowever, since the first target pattern 1021 surrounds the first exposure pattern 1011, the optical proximity correction to reduce the first edge placement error EPE1 involves translating the first correction edge 1001a toward the second correction pattern 1002 by a certain dimension. Furthermore, because the first distance d1 between the first correction edge 1001a and the second correction edge 1002a has already reached the mask rule size dr, it is impossible to continue translating the first correction edge 1001a toward the second correction pattern 1002.

[0030] In existing technologies, the adjacent edges of a current edge with edge placement errors are moved using the cross-meef effect, such as moving the two corrected edges adjacent to the first corrected edge 1002a in this embodiment. However, as nodes become smaller and the environment on the layout becomes more complex, moving adjacent edges can lead to new problems. For example, moving adjacent edges to correct the edge placement error of the current edge can easily cause the adjacent edges to generate excessive edge placement errors during the movement. This can easily cause the entire correction process to fall into an infinite loop, ultimately failing to resolve the edge placement errors corresponding to all edges.

[0031] To address the aforementioned technical problems, the present invention provides an optical proximity correction method. By iteratively traversing the optical proximity correction of several first segmented segments and several second segmented segments under different length and size combinations, the method fundamentally intervenes in the final moving layout result. Without moving adjacent edges, it effectively solves the first edge placement error under the mask's regular size constraints, thereby improving correction accuracy and efficiency.

[0032] To make the above-mentioned objectives, features and beneficial effects of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0033] Figure 4 This is a flowchart of an optical proximity correction method according to an embodiment of the present invention, including:

[0034] Step S101: Obtain a first modified layout. The first modified layout includes a first modified graphic and a second modified graphic. The first modified graphic includes a first modified edge, and the second modified graphic includes a second modified edge. The first modified edge and the second modified edge are adjacent and parallel. There is a first spacing dimension between the first modified edge and the second modified edge, and the first spacing dimension is equal to the mask rule dimension.

[0035] Step S102: Perform a first exposure process on the first corrected pattern to obtain a first exposed pattern. The first exposed pattern includes a first exposed graphic and a second exposed graphic. The first exposed graphic includes a first exposed edge corresponding to the first corrected edge, and the second exposed graphic includes a second exposed edge corresponding to the second corrected edge.

[0036] Step S103: Provide a target layout, the target layout including a first target graphic and a second target graphic, the first target graphic surrounds the first exposure graphic, the first target graphic includes a first target edge corresponding to the first exposure edge, the second target graphic surrounds the second exposure graphic, the second target graphic includes a second target edge corresponding to the second exposure edge;

[0037] Step S104: Obtain the first edge placement error between the first exposure edge and the first target edge, and the second edge placement error between the second exposure edge and the second target edge;

[0038] Step S105: Provide a preset edge placement error range, wherein the first edge placement error is greater than the preset edge placement error range, and the second edge placement error is within the preset edge placement error range;

[0039] Step S106: Perform segmentation processing on the first target graphic and the second target graphic. The segmentation processing includes dividing the first target edge of the first target graphic into several first segmentation segments, each of which has a first length dimension, and dividing the second target edge of the second target graphic into several second segmentation segments, each of which has a second length dimension.

[0040] Step S107: Provide an optical proximity correction model. Perform optical proximity correction on the segmented first target image and second target image several times according to the optical proximity correction model. Before each optical proximity correction, adjust the first length dimension of several first segmented segments and the second length dimension of several second segmented segments until the first edge placement error and the second edge placement error are both within the preset edge placement error range.

[0041] The steps of the optical proximity correction method are described in detail below with reference to the accompanying drawings.

[0042] Figures 5 to 11 This is a schematic diagram of the specific steps of the optical proximity correction method according to an embodiment of the present invention.

[0043] Obtain a first revised pattern, which includes a first revised shape and a second revised shape. The first revised shape includes a first revised edge, and the second revised shape includes a second revised edge. The first revised edge and the second revised edge are adjacent and parallel, and there is a first spacing dimension between the first revised edge and the second revised edge, which is equal to the mask rule dimension. For the specific process of obtaining the first revised pattern, please refer to [reference needed]. Figures 5 to 6 .

[0044] Please refer to Figure 5 An initial layout is provided, which includes a first graphic 2001 and a second graphic 2002. The first graphic 2001 includes a first side 2001a, and the second graphic 2002 includes a second side 2002a. The first side 2001a and the second side 2002a are adjacent and parallel.

[0045] In this embodiment, the first graphic 2001 and the second graphic 2002 in the initial layout are graphics without any optical proximity correction. Theoretically, in the absence of optical proximity effects, the first graphic 2001 is similar to the subsequently provided first target graphic, and the second graphic 2002 is similar to the subsequently provided second target graphic.

[0046] In this embodiment, the first graphic 2001 is a rectangle, and the first side 2001a is one side of the rectangle.

[0047] In this embodiment, the second graphic 2002 is a rectangle, and the second side 2002a is one side of the rectangle.

[0048] It should be noted that, in this embodiment, the first edge 2002a and the second edge 2001a being adjacent means that the first edge 2002a and the second edge 2001a have a relative projection, and there are no other edges between the segments of the first edge 2002a and the second edge 2001a that have a relative projection.

[0049] Please refer to Figure 6 An initial optical proximity correction is performed on the initial layout to obtain the first corrected layout. The first corrected layout includes a first corrected pattern 2011 and a second corrected pattern 2012. The first corrected pattern 2011 includes a first corrected edge 2011a, and the second corrected pattern 2012 includes a second corrected edge 2012a. The first corrected edge 2011a and the second corrected edge 2012a are adjacent and parallel. The first corrected edge 2011a corresponds to the first edge 2001a, and the second corrected edge 2012a corresponds to the second edge 2002a.

[0050] In this embodiment, the initial optical proximity correction is the first optical proximity correction. The initial optical proximity correction is based on the correction model to transform the first graphic 2001 and the second graphic 2002 in the initial layout, that is, to translate the first edge 2001a and the second edge 2001b by a certain size, thereby obtaining the first corrected edge 2011a and the second corrected edge 2012a.

[0051] In this embodiment, there is a first spacing dimension d1 between the first correction edge 2011a and the second correction edge 2012a, and the first spacing dimension d1 is equal to the mask rule dimension dr.

[0052] It should be noted that in this embodiment, a mask manufacturing rule check is required during the optical proximity correction process to ensure the final pattern convergence and mask fabrication accuracy. Typically, this check examines the linewidth and spacing in the optically proximity-corrected mask pattern based on a set mask rule constraint (MRC) size dr (including linewidth and spacing values). If the first spacing dimension d1 is smaller than the mask rule constraint dr, errors may easily occur or the mask fabrication process may fail.

[0053] Please refer to Figure 7 The first exposure pattern is obtained by performing a first exposure process on the first corrected pattern. The first exposure pattern includes a first exposure pattern 2021 and a second exposure pattern 2022. The first exposure pattern 2021 includes a first exposure edge 2021a corresponding to the first corrected edge 2011a, and the second exposure pattern 2022 includes a second exposure edge 2022a corresponding to the second corrected edge 2012a.

[0054] In this embodiment, the first exposure process is a simulated exposure, that is, a simulation of an actual exposure with optical proximity effect. Because the first exposure process introduces the influence parameters of optical proximity effect, the obtained first exposure pattern 2021 will have a certain distortion compared to the first pattern 2001, and the second exposure pattern 2022 will have a certain distortion compared to the second pattern 2002.

[0055] Please refer to Figure 8A target layout is provided, the target layout including a first target graphic 2031 and a second target graphic 2032, the first target graphic 2031 surrounds the first exposure graphic 2021, the first target graphic 2031 includes a first target edge 2031a corresponding to the first exposure edge 2021a, the second target graphic 2032 surrounds the second exposure graphic 2022, the second target graphic 2032 includes a second target edge 2032a corresponding to the second exposure edge 2022a.

[0056] In this embodiment, the target pattern is a graphic obtained without the influence of optical proximity effect. The first target pattern 2031 is similar to the first pattern 2001, and the second target pattern is similar to the second pattern 2002. That is, both the first target pattern 2031 and the second target pattern are rectangles.

[0057] Please refer to Figure 9 The first edge placement error EPE1 between the first exposure edge 2021a and the first target edge 2031a, and the second edge placement error EPE2 between the second exposure edge 2022a and the second target edge 2032a are obtained.

[0058] It should be noted that, in this embodiment, due to the optical proximity effect, the first exposed pattern 2021 cannot be completely identical to the first target pattern 2031. Therefore, an edge placement error (EPE) is introduced to measure the difference between the first exposed pattern 2021 and the first target pattern 2031, as well as the difference between the second exposed pattern and the second target pattern. When the edge placement error EPE is within a certain range, the difference is considered acceptable.

[0059] In this embodiment, the method for obtaining the first edge placement error EPE1 includes: obtaining a first sampling point a1 of the first exposure edge 2021a; obtaining a second sampling point a2 of the first target edge 2031a; obtaining a second spacing dimension d2 between the first sampling point a1 and the second sampling point a2, and using the second spacing dimension d2 as the first edge placement error EPE1.

[0060] In this embodiment, the method for obtaining the second edge placement error EPE1 includes: obtaining the third sampling point a3 of the second exposure edge 2022a; obtaining the fourth sampling point a4 of the second target edge 2032a; obtaining the third spacing dimension d3 between the third sampling point a3 and the fourth sampling point a4, and using the third spacing dimension d3 as the second edge placement error EPE2.

[0061] Please continue to refer to this. Figure 9Provides a preset edge placement error range (EPE) spec The first edge placement error EPE1 is greater than the preset edge placement error range EPE. spec The second edge placement error EPE2 is located within the preset edge placement error range EPE. spec Inside.

[0062] The preset edge placement error range EPE spec That is, to determine the magnitudes of the first edge placement error EPE1 and the second edge placement error EPE2, when both the first edge placement error EPE1 and the second edge placement error EPE2 are within the preset edge placement error range EPE... spec At that time, they considered such a gap to be acceptable.

[0063] However, in this embodiment, the first edge placement error EPE1 is greater than the preset edge placement error range EPE. spec Therefore, it is necessary to continue optical proximity correction on the first corrected pattern 2011 to reduce the first edge placement error EPE1 to the preset edge placement error range EPE. spec Inside.

[0064] Please refer to Figure 10 The first target graphic 2031 and the second target graphic 2032 are segmented. The segmentation process includes dividing the first target edge 2031a of the first target graphic 2031 into several first segmentation segments 2031b, each of which has a first length dimension d1, and dividing the second target edge 2032a of the second target graphic 2032 into several second segmentation segments 2032b, each of which has a second length dimension d2.

[0065] In this embodiment, before segmenting the first target graphic 2031 and the second target graphic 2032, the method further includes marking the first target edge 2031a of the first target graphic 2031 and the second target edge 2032a of the second target graphic 2032.

[0066] In this embodiment, the first target edge 2031a of the first target pattern 2031 is divided into two first segmentation segments 2031b. For example, the total length of the first target edge 2031a is 50nm, the first length dimension d1 of one of the first segmentation segments 2031b is divided into 25nm, and the first length dimension d1 of the other first segmentation segment 2031b is also divided into 25nm.

[0067] In other embodiments, the first target edge of the first target graphic may be divided into more than two first segmentation segments.

[0068] In this embodiment, the second target edge 2032a of the second target pattern 2032 is divided into two second segmentation segments 2032b. For example, the total length of the second target edge 2032a is 50nm, the second length dimension d2 of one of the second segmentation segments 2032b is divided into 25nm, and the second length dimension d2 of the other second segmentation segment 2032b is also divided into 25nm.

[0069] In other embodiments, the second target edge of the second target graphic may be divided into more than two second segmentation segments.

[0070] Please refer to Figure 11 An optical proximity correction model is provided. Based on this model, several optical proximity corrections are performed on the segmented first target image 2031 and second target image 2032. Before each optical proximity correction, the first length dimension d1 of several first segmented segments 2031b and the second length dimension d2 of several second segmented segments 2032b are adjusted until the first edge placement error EPE1 and the second edge placement error EPE2 are both within the preset edge placement error range EPE. spec That's all.

[0071] In this embodiment, by iteratively traversing the optical proximity corrections of several first segment 2031b and several second segment 2032b under different length and size combinations, the final moving pattern result is fundamentally intervened. Without moving adjacent edges, it has a good effect on solving the first edge placement error EPE1 under the mask regular size constraint, so as to improve the correction accuracy and correction efficiency.

[0072] In this embodiment, the method for adjusting the first length dimension d1 of a plurality of first segmented segments 2031b before each optical proximity correction includes: before performing the first optical proximity correction, the first length dimension d1 of the plurality of first segmented segments 2031b is the first length dimension d1 after segmenting the first target graphic 2031; before each optical proximity correction after performing the first optical proximity correction, the first length dimension d1 of one of the first segmented segments 2031b is successively increased by a first step length dimension d-step1, and the first length dimension d1 of another first segmented segment 2031b is successively decreased by the first step length dimension d-step1.

[0073] In this embodiment, the method for adjusting the second length dimension d2 of a plurality of second segmented segments 2032b before each optical proximity correction includes: before performing the first optical proximity correction, the second length dimension d2 of the plurality of second segmented segments 2032b is the second length dimension d2 after segmenting the second target graphic 2032; before each optical proximity correction after performing the first optical proximity correction, the second length dimension d2 of one of the second segmented segments 2032b is increased by a second step size d-step2, and the second length dimension d2 of the other second segmented segment 2032b is decreased by the second step size d-step2.

[0074] The range of the first step length dimension d-step1 is 0.5nm to 1.5nm; the range of the second step length dimension d-step2 is 0.5nm to 1.5nm.

[0075] In this embodiment, the first step length dimension d-step1 and the second step length dimension d-step2 are equal, and both the first step length dimension d-step1 and the second step length dimension d-step2 are 1nm.

[0076] Since the initial length dimension d1 of the two first segments 2031b is (25nm, 25nm), the corresponding segmentation results after each size adjustment are: (26nm, 24nm), (27nm, 23nm), (28nm, 22nm)...

[0077] Accordingly, since the initial second length dimension d2 of the two second segments 2032b is (25, 25), the corresponding segmentation results after each size adjustment are: (26nm, 24nm), (27nm, 23nm), (28nm, 22nm)...

[0078] In this embodiment, before each optical proximity correction, before adjusting the first length dimension d1 of the plurality of first segment 2031b and the second length dimension d2 of the plurality of second segment 2032b, the method further includes: providing a regular length dimension dmin, wherein the first length dimension d1 and the second length dimension d2 are greater than or equal to the regular length dimension dmin.

[0079] The rule length dimension dmin is the minimum length dimension that the first segment 2031b or the second segment 2032b can move. When the first length dimension d1 of the first segment 2031b or the second length dimension d2 of the second segment 2032b is less than the rule length dimension, the optical proximity correction model cannot move it further. Therefore, the first length dimension d1 and the second length dimension d2 need to be greater than or equal to the rule length dimension dmin.

[0080] It should be noted that in this embodiment, after each optical proximity correction, the corrected image must undergo a second exposure process to re-acquire the first edge placement error EPE1 and the second edge placement error EPE2. The specific acquisition process is the same as that for acquiring the first edge placement error EPE1 and the second edge placement error EPE2 after the first exposure process, and will not be described again here.

[0081] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. An optical proximity correction method, characterized in that, include: Obtain a first modified layout, which includes a first modified graphic and a second modified graphic. The first modified graphic includes a first modified edge, and the second modified graphic includes a second modified edge. The first modified edge and the second modified edge are adjacent and parallel. There is a first spacing dimension between the first modified edge and the second modified edge, and the first spacing dimension is equal to the mask rule dimension. The first exposure pattern is obtained by performing a first exposure process on the first corrected pattern. The first exposure pattern includes a first exposure graphic and a second exposure graphic. The first exposure graphic includes a first exposure edge corresponding to the first corrected edge, and the second exposure graphic includes a second exposure edge corresponding to the second corrected edge. A target layout is provided, the target layout including a first target graphic and a second target graphic, the first target graphic surrounding a first exposure graphic, the first target graphic including a first target edge corresponding to the first exposure edge, the second target graphic surrounding a second exposure graphic, the second target graphic including a second target edge corresponding to the second exposure edge; Obtain the first edge placement error between the first exposure edge and the first target edge, and the second edge placement error between the second exposure edge and the second target edge; A preset edge placement error range is provided, wherein the first edge placement error is greater than the preset edge placement error range, and the second edge placement error is within the preset edge placement error range; the first target graphic and the second target graphic are segmented, wherein the segmentation process includes dividing the first target edge of the first target graphic into several first segmentation segments, each of the first segmentation segments having a first length dimension, and dividing the second target edge of the second target graphic into several second segmentation segments, each of the second segmentation segments having a second length dimension; An optical proximity correction model is provided. Based on the optical proximity correction model, the first target image and the second target image after segmentation are subjected to several optical proximity corrections. Before each optical proximity correction, the first length dimension of several first segmentation segments and the second length dimension of several second segmentation segments are adjusted until the first edge placement error and the second edge placement error are both within the preset edge placement error range.

2. The optical proximity correction method as described in claim 1, characterized in that, The first target edge of the first target graphic is divided into two first segmentation segments.

3. The optical proximity correction method as described in claim 2, characterized in that, The method for adjusting the first length dimension of a plurality of first segmented segments before each optical proximity correction includes: before performing the first optical proximity correction, the first length dimension of the plurality of first segmented segments is the first length dimension after segmenting the first target image; before each optical proximity correction after performing the first optical proximity correction, the first length dimension of one of the first segmented segments is increased by a first step length dimension, and the first length dimension of the other first segmented segment is decreased by the first step length dimension.

4. The optical proximity correction method as described in claim 3, characterized in that, The range of the first step length dimension is 0.5nm to 1.5nm.

5. The optical proximity correction method as described in claim 1, characterized in that, The second target edge of the second target graphic is divided into two second segmentation segments.

6. The optical proximity correction method as described in claim 4, characterized in that, The method for adjusting the second length dimension of a plurality of second segments before each optical proximity correction includes: before performing the first optical proximity correction, the second length dimension of the plurality of second segments is the second length dimension after segmenting the second target image; before each optical proximity correction after performing the first optical proximity correction, the second length dimension of one of the second segments is increased by a second step size, and the second length dimension of the other second segment is decreased by a second step size.

7. The optical proximity correction method as described in claim 6, characterized in that, The range of the second step size is 0.5nm to 1.5nm.

8. The optical proximity correction method as described in claim 1, characterized in that, Before each optical proximity correction, before adjusting the first length dimension of a plurality of the first segment and the second length dimension of a plurality of the second segment, the method further includes: providing a regular length dimension, wherein the first length dimension and the second length dimension are greater than or equal to the regular length dimension.

9. The optical proximity correction method as described in claim 1, characterized in that, Before segmenting the first target graphic and the second target graphic, the method further includes: marking the first target edge of the first target graphic and the second target edge of the second target graphic.

10. The optical proximity correction method as described in claim 1, characterized in that, The method for obtaining the first corrected layout includes: providing an initial layout, the initial layout including a first graphic and a second graphic, the first graphic including a first side, the second graphic including a second side, the first side and the second side being adjacent and parallel; performing initial optical proximity correction on the initial layout to obtain the first corrected layout, wherein the first corrected side corresponds to the first side and the second corrected side corresponds to the second side.

11. The optical proximity correction method as described in claim 1, characterized in that, The method for obtaining the first edge placement error includes: obtaining a first sampling point of the first exposure edge; obtaining a second sampling point of the first target edge; obtaining a second distance dimension between the first sampling point and the second sampling point, and using the second distance dimension as the first edge placement error.

12. The optical proximity correction method as described in claim 1, characterized in that, The method for obtaining the second edge placement error includes: obtaining a third sampling point of the second exposure edge; obtaining a fourth sampling point of the second target edge; obtaining a third distance dimension between the third sampling point and the fourth sampling point, and using the third distance dimension as the second edge placement error.

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