Optical proximity correction method

Abstract

An optical proximity correction method includes: 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 and a second correction edge, the second correction graphic including a third correction edge, the third correction edge and the first correction edge having a first spacing dimension, and the first spacing dimension being equal to the mask rule dimension; acquiring a first exposure pattern, the first exposure pattern including a first exposure graphic and a second exposure graphic; providing a target pattern, the target pattern including a first target graphic; acquiring a first edge placement error between the first exposure graphic and the first target graphic; performing a plurality of optical proximity corrections on the first correction pattern, the plurality of optical proximity corrections being used to translate the first correction edge and the second correction edge so that the first edge placement error is within a preset edge placement error range, and translating the third correction edge to increase the second spacing to be greater than the preset spacing dimension, which can effectively improve the correction accuracy.

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.

[0007] To solve the above technical problems, the present invention provides an optical proximity correction method, comprising: obtaining a first correction pattern, the first correction pattern including a first correction pattern and a second correction pattern, the first correction pattern including a first correction edge and a second correction edge perpendicular to the first correction edge, the second correction pattern including a third correction edge and a fourth correction edge opposite to each other, the third correction edge being adjacent to and parallel to the first correction edge, the third correction edge having a first spacing dimension between the third correction edge and the first correction edge, and the first spacing dimension being equal to the mask regularity dimension; performing a first exposure processing on the first correction pattern to obtain a first exposure pattern, the first exposure pattern including a first exposure pattern and a second exposure pattern, the first exposure pattern including a first exposure edge corresponding to the first correction edge and a second exposure edge corresponding to the second correction edge, the second exposure pattern including a third exposure edge corresponding to the third correction edge, and a third correction edge perpendicular to the first correction edge, and a fourth correction edge opposite to each other, the third correction edge being adjacent to and parallel to the first correction edge, the third correction edge having a first spacing dimension between the third correction edge and the first correction edge, and the first correction edge having a first exposure edge corresponding to the first correction edge and a second exposure edge perpendicular to the first correction edge, the second exposure pattern having a third exposure edge corresponding to the third correction edge, and a fourth correction edge perpendicular to the first correction edge, the second exposure pattern having a third exposure edge corresponding to the third correction edge, and a fourth correction edge perpendicular to the first correction edge, the third correction edge being adjacent to and parallel to the first correction edge, the third correction edge having a first spacing dimension between the third correction edge and the first correction edge, and the first correction edge having a first exposure edge perpendicular to the first correction edge, the second exposure pattern having a first exposure edge corresponding to the first correction edge and a second exposure edge perpendicular to the first correction edge, the third correction edge having a first exposure edge perpendicular to the first correction edge, and a fourth correction edge perpendicular to the first correction edge, the second exposure pattern having a third exposure edge perpendicular to the first correction edge, the third correction edge having a first exposure edge perpendicular to the first correction edge, the second exposure edge having a third exposure edge perpendicular to the first correction edge, the third correction edge having a first exposure edge perpendicular to A fourth exposure edge corresponding to the fourth correction edge, the third exposure edge and the fourth exposure edge having a second spacing dimension, the second spacing dimension being less than or equal to a preset spacing dimension; providing a target layout, the target layout including a first 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; obtaining a first edge placement error between the first exposure edge and the first target edge; providing a preset edge placement error range; performing several optical proximity corrections on the first correction layout, the several optical proximity corrections being used to translate the first correction edge and the second correction edge so that the first edge placement error is within the preset edge placement error range, and translating the third correction edge to increase the second spacing dimension to be greater than the preset spacing dimension, and the first spacing dimension being greater than or equal to the mask rule dimension, to obtain a second correction layout.

[0008] Optionally, the first edge placement error is within the preset edge placement error range, or the first edge placement error is greater than the preset edge placement error range.

[0009] Optionally, when the first edge placement error is within the preset edge placement error range, a plurality of optical proximity corrections are used to translate the first correction edge and the second correction edge to keep the first edge placement error within the preset edge placement error range.

[0010] Optionally, when the first edge placement error is greater than the preset edge placement error range, the optical proximity correction is performed several times to translate the first correction edge and the second correction edge to reduce the first edge placement error to the preset edge placement error range.

[0011] Optionally, each optical proximity correction method includes: translating the first correction edge away from the second correction pattern by a first correction size; translating the second correction edge away from the first correction pattern by a second correction size, the second correction size being smaller than the first correction size; and translating the third correction edge closer to the first correction pattern by a third correction size, the first correction size being greater than or equal to the third correction size.

[0012] Optionally, the ratio of the first corrected dimension to the second corrected dimension is 2.5:1 to 3.5:1.

[0013] Optionally, the first correction pattern further includes a fifth correction edge perpendicular to the first correction edge; the method for each optical proximity correction further includes translating the fifth correction edge in a direction away from the first correction pattern by a fourth correction dimension, the fourth correction dimension being smaller than the first correction dimension.

[0014] Optionally, the ratio of the first corrected dimension to the fourth corrected dimension is 2.5:1 to 3.5:1.

[0015] Optionally, the first correction edge is connected to the second correction edge.

[0016] Optionally, the five corrected edges are connected to the second corrected edge.

[0017] Optionally, the method for obtaining the first corrected pattern includes: providing an initial pattern, the initial pattern including a first shape and a second shape, the first shape including a first side and a second side perpendicular to the first side, the second shape including a third side and a fourth side opposite to each other, the third side being adjacent to and parallel to the first side; performing initial optical proximity correction on the initial pattern to obtain the first corrected pattern, wherein the first corrected side corresponds to the first side, the second corrected side corresponds to the second side, the third corrected side corresponds to the third side, and the fourth corrected side corresponds to the fourth side.

[0018] Optionally, the method for obtaining the first edge placement error includes: obtaining a first sampling point of the first exposed edge; obtaining a second sampling point of the first target edge; obtaining a third distance dimension between the first sampling point and the second sampling point, and using the third distance dimension as the first 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 first corrected pattern. These corrections are used to translate the first and second correction edges so that the first edge placement error is within a preset edge placement error range, and to translate the third correction edge to increase the second spacing size to be greater than the preset spacing size. The first spacing size is greater than or equal to the mask regularity size, thereby obtaining a second corrected pattern. By performing these optical proximity corrections several times, the first edge placement error is kept within the preset edge placement error range, the second spacing size is increased to be greater than the preset spacing size, and the first spacing size is ensured to be greater than or equal to the mask regularity size, effectively improving the correction accuracy. 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 10 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 1A first corrected pattern is obtained, comprising a first corrected shape 1001 and a second corrected shape 1002. The first corrected shape 1001 includes a first corrected edge 1001a and a second corrected edge 1001b perpendicular to the first corrected edge 1001a. The second corrected shape 1002 includes a third corrected edge 1002a and a fourth corrected edge 1002b opposite to each other. The third corrected edge 1002a is adjacent to and parallel to the first corrected edge 1001a, and there is a first spacing dimension d1 between the third corrected edge 1002a and the first corrected edge 1001a, wherein the first spacing dimension d1 is equal to the mask rule dimension dr. A first exposure process is performed on the first corrected pattern to obtain... A first exposure pattern is taken, which includes a first exposure pattern 1011 and a second exposure pattern 1012. The first exposure pattern 1011 includes a first exposure edge 1011a corresponding to the first correction edge 1001a and a second exposure edge 1011b corresponding to the second correction edge 1001b. The second exposure pattern 1012 includes a third exposure edge 1012a corresponding to the third correction edge 1002a and a fourth exposure edge 1012b corresponding to the fourth correction edge 1002b. The third exposure edge 1012a and the fourth exposure edge 1012b have a second spacing dimension d2, which is less than or equal to a preset spacing dimension dp.

[0027] Please refer to Figure 2 The system provides a target layout, which includes a first target pattern 1021 that surrounds a first exposure pattern 1011. The first target pattern 1021 includes a first target edge 1021a corresponding to the first exposure edge 1011a. It also obtains a first edge placement error EPE1 between the first exposure edge 1011a and the first target edge 1021a, and 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 .

[0028] In this embodiment, the second spacing dimension d2 between the third exposure edge 1012a and the fourth exposure edge 1012b is smaller than the preset spacing dimension dp. The second spacing dimension d2 corresponds to the size of the photoresist retained after exposure in the actual semiconductor process. If the second spacing dimension d2 is smaller than the preset spacing dimension dp, the corresponding photoresist will be very narrow, thus increasing the risk of collapse. Additionally, the first edge placement error EPE1 is greater than the preset edge placement error range EPE. specThis results in the final graphic size not meeting design requirements. Therefore, optical proximity correction processing is needed on the first corrected pattern to increase the second spacing dimension d2 to be greater than the preset spacing dimension dp, while simultaneously reducing the first edge placement error EPE1 to the preset edge placement error range EPE. spec Inside.

[0029] It should be noted that in this embodiment, the processing priority of increasing the second spacing dimension d2 is higher than the processing priority of reducing the first edge placement error EPE1.

[0030] In this embodiment, the method of increasing the second spacing dimension d2 includes: translating the third correction edge 1002a toward a direction closer to the first correction pattern 100, and translating the fourth correction edge 1002b toward a direction away from the first correction pattern 100.

[0031] If the third corrected edge 1002a is translated toward the first corrected pattern 100, the first spacing dimension d1 will decrease, making the first spacing dimension d1 smaller than the mask rule dimension dr. When the first spacing dimension d1 is smaller than the mask rule dimension dr, it will be easy to make errors or make the mask impossible to manufacture.

[0032] Please refer to Figure 3 To ensure that the first spacing dimension d1 is not less than the mask rule dimension dr, the first correction edge 1001a and the third correction edge 1002a need to be translated in the same direction, and the translation size of the first correction edge 1001a must be greater than or equal to the translation size of the third correction edge 1002a. However, when the first correction edge 1001a is also translated towards the direction closer to the first correction pattern 100, while keeping the position of the second correction edge 1001b unchanged, the first edge placement error EPE1 will further increase, making it impossible to reduce the first edge placement error EPE1 to the preset edge placement error range EPE. spec The requirements within. Even if the initial first edge placement error EPE1 is within the preset edge placement error range EPE. spec However, after the first corrected edge 1001a is also translated towards the direction closer to the first corrected pattern 1001, the first edge placement error EPE1 is easily increased to a value greater than the preset edge placement error range EPE. spec Therefore, the optical proximity correction cannot simultaneously increase the second spacing dimension d2 and reduce the first edge placement error EPE1, resulting in poor final correction accuracy.

[0033] To solve the above-mentioned technical problems, the technical solution of the present invention provides an optical proximity correction method. Through several optical proximity corrections, the first edge placement error is reduced to within the preset edge placement error range, while the second spacing size is increased to be greater than the preset spacing size. At the same time, the first spacing size is ensured to be greater than or equal to the mask regular size, which can effectively improve the correction accuracy.

[0034] 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.

[0035] Figure 4 This is a flowchart of an optical proximity correction method according to an embodiment of the present invention, including:

[0036] 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 a second modified edge perpendicular to the first modified edge. The second modified graphic includes a third modified edge and a fourth modified edge opposite to each other. The third modified edge is adjacent to and parallel to the first modified edge. The third modified edge and the first modified edge have a first spacing dimension, and the first spacing dimension is equal to the mask rule dimension.

[0037] 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 a second exposed edge corresponding to the second corrected edge. The second exposed graphic includes a third exposed edge corresponding to the third corrected edge and a fourth exposed edge corresponding to the fourth corrected edge. There is a second spacing dimension between the third exposed edge and the fourth exposed edge. The second spacing dimension is less than or equal to a preset spacing dimension.

[0038] Step S103: Provide a target layout, the target layout including a first target graphic, the first target graphic including a first target edge corresponding to the first exposure edge;

[0039] Step S104: Obtain the first edge placement error between the first exposure edge and the first target edge;

[0040] Step S105: Provide a preset edge placement error range;

[0041] Step S106: Perform several optical proximity corrections on the first corrected pattern. The several optical proximity corrections are used to translate the first corrected edge and the second corrected edge so that the first edge placement error is within the preset edge placement error range, and to translate the third corrected edge to increase the second spacing size to be greater than the preset spacing size, and the first spacing size is greater than or equal to the mask rule size, to obtain the second corrected pattern.

[0042] The steps of the optical proximity correction method are described in detail below with reference to the accompanying drawings.

[0043] Figures 5 to 10 This is a schematic diagram of the specific steps of the optical proximity correction method according to an embodiment of the present invention.

[0044] 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 a second revised edge perpendicular to the first revised edge. The second revised shape includes a third revised edge and a fourth revised edge opposite to each other. The third revised edge is adjacent to and parallel to the first revised edge, and there is a first spacing dimension between the third revised edge and the first 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 .

[0045] 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 a second side 2001b perpendicular to the first side 2001a. The second graphic 2002 includes a third side 2002a and a fourth side 2002b, which are adjacent to and parallel to the first side 2001a.

[0046] 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.

[0047] In this embodiment, the first shape 2001 is a rectangle, and the first side 2001a and the second side 2001b are two sides connected to each other.

[0048] In this embodiment, the first pattern 2001 further includes a fifth side 2001c that is perpendicular to the first side 2001a, and the fifth side 2001c is connected to the first side 2001a.

[0049] In this embodiment, the second shape 2002 is a rectangle, and the third side 2002a and the fourth side 2002b are two opposite and parallel sides. In other embodiments, the second shape is "L" shaped.

[0050] It should be noted that, in this embodiment, the adjacency of the third side 2002a and the first side 2001a means that there is a relative projection between the third side 2002a and the first side 2001a, and there are no other sides between the segments of the third side 2002a and the first side 2001a that have a relative projection.

[0051] Please refer to Figure 6 An initial optical proximity correction is performed on the initial layout to obtain the first corrected layout, wherein the first corrected edge 2011a corresponds to the first edge 2001a, the second corrected edge 2011b corresponds to the second edge 2001b, the third corrected edge 2012a corresponds to the third edge 2002a, and the fourth corrected edge 2012b corresponds to the fourth edge 2002b.

[0052] 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. Specifically, the first edge 2001a, the second edge 2001b, the third edge 2002a, and the fourth edge 2002b are translated by a certain size to obtain the first corrected edge 2011a, the second corrected edge 2011b, the third corrected edge 2012a, and the fourth corrected edge 2012b.

[0053] In this embodiment, the fifth side 2001c is also translated by a certain size to obtain the fifth corrected side 2011c.

[0054] It should be noted that the first corrected edge 2011a can be a whole edge corresponding to the first edge 2001a, or it can be a segment of a whole edge corresponding to the first edge 2001a.

[0055] In this embodiment, the first corrected edge 2011a is a segment of an edge, and the corresponding second corrected edge 2011b, third corrected edge 2012a, fourth corrected edge 2012b and fifth corrected edge 2011c are all segments of a whole edge.

[0056] In this embodiment, the third correction edge 2012a and the first correction edge 2011a have a first spacing dimension d1, and the first spacing dimension d1 is equal to the mask rule dimension dr.

[0057] 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.

[0058] 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 a second exposure edge 2021b corresponding to the second corrected edge 2011b. The second exposure pattern 2022 includes a third exposure edge 2022a corresponding to the third corrected edge 2012a and a fourth exposure edge 2022b corresponding to the fourth corrected edge 2012b. There is a second spacing dimension d2 between the third exposure edge 2022a and the fourth exposure edge 2022b. The second spacing dimension d2 is less than or equal to a preset spacing dimension dp.

[0059] 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.

[0060] In this embodiment, the first exposure pattern 2021 also includes a fifth exposure edge 2021c corresponding to the fifth correction edge 2011c.

[0061] Please refer to Figure 8 A target layout is provided, the target layout including a first target graphic 2031, the first target graphic 2031 surrounding the first exposure graphic 2021, the first target graphic 2031 including a first target edge 2031a corresponding to the first exposure edge 2021a.

[0062] In this embodiment, the first target pattern 2031 further includes: a second target edge (not shown) corresponding to the second exposure edge 2021b, and a fifth target edge (not shown) corresponding to the fifth exposure edge 2021c.

[0063] In this embodiment, the target layout further includes a second target graphic (not shown), which includes a third target edge corresponding to the third exposure edge 2022a and a fourth target edge corresponding to the fourth exposure edge 2022b.

[0064] 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.

[0065] Please refer to Figure 9 The first edge placement error EPE1 between the first exposure edge 2021a and the first target edge 2031a is obtained.

[0066] It should be noted that, in this embodiment, due to the optical proximity effect, the first exposure 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 exposure pattern 2021 and the first target pattern 2031. When the edge placement error EPE is within a certain range, the difference is considered acceptable.

[0067] 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 third spacing dimension d3 between the first sampling point a1 and the second sampling point a2, and using the third spacing dimension d3 as the first edge placement error EPE1.

[0068] It should be noted that, in this embodiment, the method further includes: obtaining the second edge placement error EPE2 between the second exposure edge 2021b and the second target edge, the third edge placement error EPE3 between the third exposure edge 2022a and the third target edge, the fourth edge placement error EPE4 between the fourth exposure edge 2022b and the fourth target edge, and the fifth edge placement error EPE5 (not shown) between the fifth exposure edge 2021c and the fifth target edge 203a.

[0069] Please continue to refer to this. Figure 9Provides a preset edge placement error range (EPE) spec .

[0070] In this embodiment, the preset edge placement error range EPE spec That is, to determine the magnitude of the first edge placement error EPE1, when the first edge placement error EPE1 is within the preset edge placement error range EPE spec At that time, they considered such a gap to be acceptable.

[0071] In this embodiment, the first edge placement error EPE1 is greater than the preset edge placement error range EPE. spec In other embodiments, the first edge placement error may also be within the preset edge placement error range.

[0072] In this embodiment, the second edge placement error EPE2, the third edge placement error EPE3, the fourth edge placement error EPE4, and the fifth edge placement error EPE5 are all within the preset edge placement error range EPE. spec Inside.

[0073] Please refer to Figure 10 The first corrected pattern is subjected to several optical proximity corrections. These optical proximity corrections are used to translate the first corrected edge 2011a and the second corrected edge 2011b so that the first edge placement error EPE1 is within the preset edge placement error range EPE. spec The second corrected pattern is obtained by translating the third corrected edge 2012a to increase the second spacing size d2 to be greater than the preset spacing size dp, and the first spacing size d1 is greater than or equal to the mask rule size dr.

[0074] In this embodiment, by performing several optical proximity corrections, the first edge placement error is reduced to within the preset edge placement error range, and the second spacing size d2 is increased to be greater than the preset spacing size dp. At the same time, the first spacing size d1 is ensured to be greater than or equal to the mask regularity size dr, which can effectively improve the correction accuracy.

[0075] In this embodiment, since the first edge placement error EPE1 is greater than the preset edge placement error range EPE spec Therefore, the optical proximity correction is performed several times to translate the first correction edge 2011a and the second correction edge 2011b to reduce the first edge placement error EPE1 to the preset edge placement error range EPE. spec Inside.

[0076] In other embodiments, when the first edge placement error is within the preset edge placement error range, a plurality of optical proximity corrections are used to translate the first correction edge and the second correction edge to keep the first edge placement error within the preset edge placement error range.

[0077] In this embodiment, each optical proximity correction method includes: translating the first correction edge 2011a away from the second correction pattern 2012 by a first correction dimension c1; translating the second correction edge 2011b away from the first correction pattern 2011 by a second correction dimension c2, wherein the second correction dimension c2 is smaller than the first correction dimension c1; and translating the third correction edge 2012a closer to the first correction pattern 2011 by a third correction dimension c3, wherein the first correction dimension c1 is greater than or equal to the third correction dimension c3.

[0078] It should be noted that, in this embodiment, after each optical proximity correction, the corrected first correction pattern is subjected to a second exposure process to obtain a second exposure pattern. The second exposure pattern includes a sixth exposure edge 2041a corresponding to the first correction edge 2011a, a seventh exposure edge 2041b corresponding to the second correction edge 2011b, an eighth exposure edge 2042a corresponding to the third correction edge 2012a, a ninth exposure edge 2042b corresponding to the fourth correction edge 2012b, and a tenth exposure edge 2041c corresponding to the fifth correction edge 2011c.

[0079] In this embodiment, since increasing the second spacing dimension d2 has a higher processing priority than decreasing the first edge placement error EPE1, the third correction edge 2012a needs to be translated by a third correction dimension c3 toward the first correction pattern 2011. During the translation of the third correction edge 2012a toward the first correction pattern 2011, the first spacing dimension d1 continuously decreases. To prevent the first spacing dimension d1 from becoming smaller than the mask rule size, the corresponding first correction edge 2011a also needs to be translated by a first correction dimension c1 toward the direction away from the second correction pattern 2012, and the first correction dimension c1 must be larger than the third correction dimension c3. However, when the first correction edge 2011a is translated by a first correction dimension c1 in a direction away from the second correction pattern 2012, the first edge placement error EPE1 will continuously increase. In order to overcome the increase of the first edge placement error EPE1 and at the same time ensure that the first edge placement error EPE1 is reduced, the second correction edge 2011b is translated by a second correction dimension c1 in a direction away from the first correction pattern 2011. By utilizing the correlation effect of the second correction edge 2011b, the sixth exposure edge 2041a in the second exposure pattern is moved in a direction closer to the first target edge 2031a, thereby achieving the effect of reducing the first edge placement error EPE1 (at this time, the first edge placement error EPE1 is the distance between the sampling point in the sixth exposure edge 2041a and the corresponding sampling point in the first target edge 2031a).

[0080] In this embodiment, under the premise of moving the same correction size, the distance by which the sixth exposure edge 2041a moves towards the direction closer to the first target edge 2031a due to the associated influence is greater than the distance by which the sixth exposure edge 2041a moves away from the first target edge 2031a after directly translating the first correction edge 2011a. Therefore, the second correction size c2 is smaller than the first correction size c1.

[0081] In this embodiment, the ratio of the first corrected size c1 to the second corrected size c2 is 2.5:1 to 3.5:1.

[0082] In this embodiment, each optical proximity correction method further includes: translating the fifth correction edge 2011c in a direction away from the first correction pattern 2011 by a fourth correction dimension c4, wherein the fourth correction dimension c4 is smaller than the first correction dimension c1. By simultaneously moving the fifth correction edge 2011c, the first edge placement error EPE1 can be reduced more quickly.

[0083] In this embodiment, the ratio of the first corrected size c1 to the fourth corrected size c4 is 2.5:1 to 3.5:1.

[0084] In this embodiment, the first correction edge 2011a is connected to the second correction edge 2011b; the fifth correction edge 2011c is connected to the second correction edge 2011b. Since a correction edge closer to the first correction edge 2011a has a greater impact on the first edge placement error EPE1, moving the second correction edge 2011b connected to the first correction edge 2011a can more quickly reduce the first edge placement error EPE1 to the preset edge placement error range EPE. spec Inside.

[0085] 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 by, 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 a second modified edge perpendicular to the first modified edge. The second modified graphic includes a third modified edge and a fourth modified edge opposite to each other. The third modified edge is adjacent to and parallel to the first modified edge. The third modified edge and the first modified edge have a first spacing dimension, 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 a second exposure edge corresponding to the second corrected edge. The second exposure graphic includes a third exposure edge corresponding to the third corrected edge and a fourth exposure edge corresponding to the fourth corrected edge. The third exposure edge and the fourth exposure edge have a second spacing dimension, which is less than or equal to a preset spacing dimension. A target layout is provided, the target layout including a first 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; Obtain the first edge placement error between the first exposure edge and the first target edge; Provides a preset edge placement error range; The first corrected pattern is subjected to several optical proximity corrections. The several optical proximity corrections are used to translate the first corrected edge and the second corrected edge so that the first edge placement error is within the preset edge placement error range, and to translate the third corrected edge to increase the second spacing size to be greater than the preset spacing size, and the first spacing size is greater than or equal to the mask rule size, to obtain the second corrected pattern.

2. The optical proximity correction method of claim 1, wherein, The first edge placement error is within the preset edge placement error range, or the first edge placement error is greater than the preset edge placement error range.

3. The optical proximity correction method of claim 2, wherein, When the first edge placement error is within the preset edge placement error range, the optical proximity correction is performed several times to translate the first correction edge and the second correction edge to keep the first edge placement error within the preset edge placement error range.

4. The optical proximity correction method of claim 2, wherein, When the first edge placement error is greater than the preset edge placement error range, the optical proximity correction is performed several times to translate the first correction edge and the second correction edge to reduce the first edge placement error to the preset edge placement error range.

5. The optical proximity correction method as described in claim 3 or 4, characterized in that, Each optical proximity correction method includes: translating the first correction edge away from the second correction pattern by a first correction size; translating the second correction edge away from the first correction pattern by a second correction size, the second correction size being smaller than the first correction size; and translating the third correction edge closer to the first correction pattern by a third correction size, the first correction size being greater than or equal to the third correction size.

6. The optical proximity correction method as described in claim 5, characterized in that, The ratio of the first corrected dimension to the second corrected dimension is 2.5:1 to 3.5:

1.

7. The optical proximity correction method as described in claim 5, characterized in that, The first correction pattern further includes a fifth correction edge perpendicular to the first correction edge; the method of each optical proximity correction further includes translating the fifth correction edge in a direction away from the first correction pattern by a fourth correction dimension, the fourth correction dimension being smaller than the first correction dimension.

8. The optical proximity correction method as described in claim 7, characterized in that, The ratio of the first corrected dimension to the fourth corrected dimension is 2.5:1 to 3.5:

1.

9. The optical proximity correction method as described in claim 1, characterized in that, The first correction edge is connected to the second correction edge.

10. The optical proximity correction method as described in claim 7, characterized in that, The fifth correction edge is connected to the second correction edge.

11. The optical proximity correction method as described in claim 1, characterized in that, The method for obtaining the first corrected pattern includes: providing an initial pattern, the initial pattern including a first shape and a second shape, the first shape including a first side and a second side perpendicular to the first side, the second shape including a third side and a fourth side opposite to each other, the third side being adjacent to and parallel to the first side; performing initial optical proximity correction on the initial pattern to obtain the first corrected pattern, wherein the first corrected side corresponds to the first side, the second corrected side corresponds to the second side, the third corrected side corresponds to the third side, and the fourth corrected side corresponds to the fourth side.

12. 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 third distance dimension between the first sampling point and the second sampling point, and using the third distance dimension as the first edge placement error.

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