Optical Proximity Correction Method

Abstract

An optical proximity correction method comprises: providing a target layout, the target layout including a plurality of target graphics; obtaining an initial layout, the initial layout including a plurality of initial graphics corresponding to the plurality of target graphics; performing exposure processing on the initial layout to obtain an initial exposure layout; comparing the initial exposure layout with the target layout to obtain a plurality of defects in the initial exposure layout, and obtaining a plurality of edge placement errors corresponding to the plurality of defects; obtaining a plurality of graphics to be offset from the plurality of initial graphics based on the plurality of edge placement errors; offsetting each of the graphics to be offset based on the plurality of edge placement errors corresponding to each of the graphics to be offset to form an initial correction layout; performing a plurality of local optical proximity corrections on the initial correction layout to obtain a correction layout, so as to reduce EPE defects in the local optical proximity correction and improve the graphic accuracy of the correction layout.

Description

Technical Field

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

[0002] Photolithography is a crucial technology in semiconductor manufacturing. It enables the transfer of patterns from a mask onto the surface of a silicon wafer, creating semiconductor products that meet design requirements. The photolithography process consists of an exposure step, a development step following the exposure step, and an etching step following the development step. During the exposure step, light passes through the light-transmitting areas of the mask onto a silicon wafer coated with photoresist, causing the photoresist to undergo a chemical reaction under the irradiation of light. During the development step, the different solubility of the developer in the photosensitive and unsensitive photoresists is exploited to form a photoresist pattern, enabling the transfer of the mask pattern to the photoresist. During the etching step, the silicon wafer is etched based on the photoresist pattern formed in the photoresist layer, further transferring the mask pattern to the wafer.

[0003] In semiconductor manufacturing, as design dimensions continue to shrink, approaching the limits of photolithography imaging systems, the diffraction effect of light becomes increasingly pronounced, ultimately leading to optical image degradation of the designed pattern. The actual photolithography pattern formed is severely distorted relative to the pattern on the mask, and the actual pattern formed by photolithography on the silicon wafer is ultimately different from the designed pattern. This phenomenon is called the Optical Proximity Effect (OPE).

[0004] Optical Proximity Correction (OPC) was developed to correct for the optical proximity effect. The core concept of OPC is to establish an OPC model based on the consideration of offsetting the optical proximity effect. The photomask pattern is designed based on the OPC model. This allows the photomask pattern to be closer to the target pattern desired by the user, even though the optical proximity effect may occur in the photolithography pattern relative to the mask pattern after photolithography. This offset has been taken into account when designing the photomask pattern based on the OPC model.

[0005] However, there are still many problems with optical proximity correction in the prior art. Summary of the Invention

[0006] The technical problem solved by the present invention is to provide an optical proximity correction method to reduce EPE defects in local optical proximity correction and improve the graphic accuracy of the corrected layout.

[0007] In order to solve the above technical problems, the technical solution of the present invention provides an optical proximity correction method, including: providing a target layout, wherein the target layout includes several target graphics; obtaining an initial layout, wherein the initial layout includes several initial graphics corresponding to the several target graphics; exposing the initial layout to obtain an initial exposure layout; comparing the initial exposure layout with the target layout to obtain several defects in the initial exposure layout, and obtaining several edge placement errors corresponding to the several defects; obtaining several graphics to be offset from the several initial graphics based on the several edge placement errors; offsetting each graphics to be offset based on the several edge placement errors corresponding to each graphics to be offset to form an initial correction layout; performing several local optical proximity corrections on the initial correction layout to obtain a correction layout.

[0008] Optionally, the method of obtaining several graphics to be offset in several initial graphics based on the several edge placement errors includes: obtaining several corresponding line segments to be corrected in several initial graphics based on the several edge placement errors corresponding to the several defects; obtaining several first specified line segments that meet preset conditions and second specified line segments corresponding to each first specified line segment among the several line segments to be corrected; and using the several initial graphics where the several first specified line segments and the several second specified line segments are located as several graphics to be offset.

[0009] Optionally, the preset conditions include: the edge placement error corresponding to the first specified line segment is greater than zero, the edge placement error corresponding to the second specified line segment is less than zero, and the corresponding first specified line segment and second specified line segment are parallel to each other and correspond to opposite edges in the same target graphic.

[0010] Optionally, the preset condition also includes: the absolute value of any specified edge placement error deviation value | EPE i |=||EPE1 i |-|EPE2 i || Below the preset value, wherein the |EPE1 i | is the absolute value of the edge placement error corresponding to any first specified line segment, the |EPE2 i | is the absolute value of the edge placement error corresponding to the second designated line segment corresponding to the arbitrary first designated line segment.

[0011] Optionally, the preset value is 1 nanometer.

[0012] Optionally, the method for obtaining corresponding line segments to be corrected in several initial graphics includes: segmenting the contours of the several initial graphics to form several initial segments; and determining several line segments to be corrected in the several initial segments based on several edge placement errors corresponding to the several defects.

[0013] Optionally, the figure to be offset where any first specified line segment is located also includes: a first line segment and a protruding line segment within the first line, the first line segment has the same extension direction as the any first specified line segment and corresponds to the same side of the target figure, and the protruding line segment within the first line connects the any first specified line segment and the first line segment.

[0014] Optionally, the figure to be offset where any first specified line segment is located also includes: a second line segment and a protruding line segment within the second line, the second line segment has the same extension direction as the first specified line segment, and the second line segment and the second specified line segment corresponding to the any first specified line segment correspond to the same side of the target figure, and the protruding line segment within the second line connects the second line segment and the second specified line segment.

[0015] Optionally, based on a number of edge placement errors corresponding to each graphic to be offset, the method of offsetting each graphic to be offset includes: obtaining an offset distance according to the edge placement error corresponding to any first specified line segment and the edge placement error corresponding to the second specified line segment corresponding to the arbitrary first specified line segment; offsetting the graphic to be offset where the arbitrary first specified line segment is located by the offset distance along the offset direction, and the offset direction is in a direction perpendicular to the extension direction of the arbitrary first specified line segment, from the arbitrary first specified line segment toward the corresponding second specified line segment.

[0016] Optionally, the offset distance S=(|EPE1 i |+|EPE2 i |) / 2, where |EPE1 i | is the absolute value of the edge placement error corresponding to the arbitrary first specified line segment, the |EPE2 i | is the absolute value of the edge placement error corresponding to the second designated line segment corresponding to the arbitrary first designated line segment.

[0017] Optionally, the initial exposure layout includes: several initial exposure patterns corresponding to several initial patterns; the method of comparing the initial exposure layout with the target layout, obtaining several defects in the initial exposure layout, and obtaining several edge placement errors corresponding to the several defects includes: obtaining several edge placement errors based on contour deviations between several target patterns and several initial exposure patterns; when any edge placement error among the several edge placement errors exceeds a preset deviation range, it is determined that a defect is detected, and the arbitrary edge placement error is used as the edge placement error corresponding to the defect.

[0018] Optionally, the obtaining of the initial layout includes: performing a plurality of global optical proximity corrections on the target layout to obtain the initial layout.

[0019] Optionally, performing several global optical proximity corrections on the target layout to obtain an initial layout includes: taking the target layout as the target layout to be corrected, and performing exposure processing to obtain an intermediate target exposure layout; performing global correction processing on the target layout to be corrected according to a preset model, the target layout and the intermediate target exposure layout to generate an intermediate target layout; taking the intermediate target layout as the target layout to be corrected until several global optical proximity corrections are completed to obtain an initial layout.

[0020] Optionally, performing several local optical proximity corrections on the initial revised layout to obtain a revised layout includes: using the initial revised layout as an intermediate layout to be corrected, and performing exposure processing to obtain an intermediate corrected exposure layout; forming an intermediate revised layout based on the target layout, the intermediate layout to be corrected, and the intermediate corrected exposure layout; using the intermediate revised layout as the intermediate layout to be corrected, and continuing to perform local optical proximity corrections until several local optical proximity corrections are completed to obtain a revised layout.

[0021] Optionally, the intermediate layout to be corrected includes several intermediate correction patterns, and the intermediate correction exposure layout includes several intermediate correction exposure patterns; forming the intermediate correction layout based on the target layout, the intermediate layout to be corrected and the intermediate correction exposure layout includes: obtaining several defects and corresponding several edge placement errors of the intermediate correction exposure layout based on the contour deviations between the several intermediate correction exposure patterns and the several target patterns; dividing the contours of the several intermediate correction patterns to form several intermediate correction segments; obtaining several corresponding intermediate line segments to be corrected in the several intermediate correction segments based on several edge placement errors corresponding to the several defects of the intermediate correction exposure layout; and offsetting several intermediate line segments to be corrected based on several edge placement errors corresponding to the several defects of the intermediate correction exposure layout to form the intermediate correction layout.

[0022] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0023] In the optical proximity correction method provided by the technical solution of the present invention, after obtaining an initial layout and before performing local optical proximity correction, the initial exposure layout is compared with the target layout to obtain a number of defects in the initial exposure layout and a number of edge placement errors corresponding to the defects. Then, based on the edge placement errors, a number of patterns to be offset are obtained from the initial patterns. Furthermore, based on the edge placement errors corresponding to each pattern to be offset, each pattern to be offset is offset to form an initial corrected layout. Therefore, in the local optical proximity correction based on the initial corrected layout, the risk of fragments that need to be offset due to edge placement errors not falling within the expected range being unable to be offset or stuck due to preset constraints (e.g., a minimum spacing with surrounding patterns) is reduced. Consequently, edge placement error defects (EPEs) that cannot be corrected in the local optical proximity correction are reduced. Furthermore, the accuracy of the local optical proximity correction is improved, and the pattern transferred based on the corrected layout is closer to the target layout, thereby improving the pattern accuracy of the corrected layout. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figures 1 to 4 is a schematic diagram of the steps in an nth local optical proximity repair method;

[0025] Figure 5 is a flow chart of an optical proximity correction method according to a real-time embodiment of the present invention;

[0026] Figures 6 to 13 FIG. 1 is a structural diagram of each step of an optical proximity correction method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] As described in the background art, there are still many problems with optical proximity correction in the prior art, which will be described in detail below with reference to the accompanying drawings.

[0028] An optical proximity correction method includes the following steps: step S11, providing a target layout; step S12, performing several global optical proximity corrections on the target layout to form an initial layout; step S13, performing several local optical proximity repairs on the initial layout.

[0029] Figures 1 to 4 Schematic diagram of the steps in an nth-order local optical proximity repair method.

[0030] Please refer to Figure 1 , for the n-1th intermediate layout 100 n-1 Simulate exposure to form the n-1th intermediate exposure pattern 120 n-1 .

[0031] Among them, the n-1 middle layout 100 n-1 Including: a number of n-1 intermediate graphics 110 n-1 When n=1, the n-1th intermediate layout 100 n-1 It is the initial layout, several n-1 intermediate graphics 110 n-1 are several initial graphics in the initial layout. The n-1th intermediate exposure layout 120 n-1 Including: and a number of n-1 intermediate graphics 110 n-1 Corresponding n-1th intermediate exposure patterns 121 n-1 .

[0032] Please refer to Figure 2 , the n-1 middle exposure layout 120 n-1 Compare with the target layout and detect the n-1 intermediate exposure layout 120 n-1 Several EPE defects.

[0033] The n-1th intermediate exposure layout 120 n-1 In the example, there is an n-1th intermediate exposure pattern 121 that needs to be offset as a whole in the direction Y to meet the expected deviation (Spec). n-1 (like Figure 2 shown in area A).

[0034] It should be noted that Figure 2 For ease of understanding, the dotted line schematically represents the n-1th intermediate exposure pattern 121 in area A. n-1 The corresponding target graphic outline 10.

[0035] Please refer to Figure 3 , for the n-1th intermediate layout 100 n-1 Several n-1 intermediate figures 110 n-1 Perform contour segmentation to form several n-1 segments 111 n-1 .

[0036] Please refer to Figure 4 , according to several EPE defects, in several n-1 segments 111 n-1 Obtain the corresponding number of fragments to be corrected 112 n-1 Then, according to each EPE defect, the corresponding segment to be corrected 112 is offset n-1 , forming the nth intermediate layout.

[0037] However, if the n-1th intermediate exposure pattern 121 in the region A n-1 The corresponding n-1th intermediate figure 110 n-1 In the outline, there are protruding line segments (jog) 114 inside the line n-1Two segments to be corrected connected 112 n-1 (like Figure 4 As shown in the area B and area C of FIG, and the two segments to be corrected 112 n-1 The positions are relative and both need to be in direction Y (the n-1 middle exposure pattern 121 in area A) n-1 When the two segments to be corrected 112 are offset in the direction of the overall offset to perform local optical proximity iterative repair, n-1 The middle back to the n-1th intermediate figure 110 n-1 One of the offsets (shown in area B) is likely to reach the minimum preset distance with the surrounding graphics and cannot be offset, resulting in the segment to be corrected 112 n-1 The corresponding EPE defects cannot be corrected. Therefore, after local optical proximity repair, there are many EPE defects and the correction accuracy is poor.

[0038] In order to solve the above technical problems, the technical solution of the present invention provides an optical proximity correction method. After obtaining the initial layout and before performing local optical proximity correction, several graphics to be offset are obtained, and based on several edge placement errors corresponding to each graphic to be offset, each graphic to be offset is offset to form an initial corrected layout. Therefore, EPE defects that cannot be repaired in local optical proximity correction can be reduced, thereby improving the graphic accuracy of the corrected layout.

[0039] 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.

[0040] Figure 5 It is a flowchart of an optical proximity correction method according to a real-time embodiment of the present invention.

[0041] Please refer to Figure 5 , the optical proximity correction method comprises the following steps:

[0042] Step S100, providing a target layout, wherein the target layout includes a plurality of target graphics;

[0043] Step S200, obtaining an initial layout, wherein the initial layout includes a plurality of initial graphics corresponding to a plurality of target graphics;

[0044] Step S300, performing exposure processing on the initial layout to obtain an initial exposure layout;

[0045] Step S400, comparing the initial exposure layout with the target layout, obtaining a number of defects in the initial exposure layout, and obtaining a number of edge placement errors corresponding to the number of defects;

[0046] Step S500, obtaining a plurality of graphics to be offset from a plurality of initial graphics according to the plurality of edge placement errors;

[0047] Step S600 , shifting each pattern to be shifted based on a number of edge placement errors corresponding to each pattern to be shifted to form an initial corrected layout;

[0048] Step S700 , performing several local optical proximity corrections on the initial revised layout to obtain a revised layout.

[0049] The following is a detailed description with reference to the accompanying drawings.

[0050] Figures 6 to 13 FIG. 1 is a structural diagram of each step of an optical proximity correction method according to an embodiment of the present invention.

[0051] Please refer to Figure 6 , providing a target layout 200 , wherein the target layout 200 includes a plurality of target graphics 210 .

[0052] The target pattern 210 is an ideal pattern (i.e., one without an optical proximity effect). However, due to the optical proximity effect, light interference and diffraction occur during the actual exposure process. Consequently, the pattern obtained after the exposure process differs from the target pattern 210. For example, if the target pattern 210 is a regular rectangle, the pattern obtained after the exposure process may resemble an ellipse. The shapes of the target patterns 210 may be rectangular, square, polygonal, circular, and so on.

[0053] For ease of explanation, Figure 6 The rectangular target graphic 210 is schematically shown in FIG. 2 for explanation.

[0054] Please refer to Figure 7 , obtaining an initial layout 300 , wherein the initial layout 300 includes a plurality of initial graphics 310 corresponding to the plurality of target graphics 210 .

[0055] In this embodiment, obtaining the initial layout 300 includes performing a plurality of global optical proximity corrections on the target layout 200 to obtain the initial layout 300 .

[0056] In this embodiment, the target layout 200 is subjected to several global optical proximity corrections to obtain the initial layout 300, including: using the target layout 200 as the target layout to be corrected, and performing exposure processing to obtain an intermediate target exposure layout (not shown); performing global correction processing on the target layout to be corrected according to a preset model, the target layout 200 and the intermediate target exposure layout to generate an intermediate target layout (not shown); using the intermediate target layout as the target layout to be corrected until several global optical proximity corrections are completed to obtain the initial layout 300.

[0057] Specifically, the method for performing the nth global optical proximity correction includes: using the n-1th intermediate target layout (not shown) as the nth target layout to be corrected, and performing exposure processing to obtain the nth intermediate target exposure layout (not shown); according to the preset model, the target layout 200, and the nth intermediate target exposure layout, globally correcting the nth target layout to be corrected to form the nth intermediate target layout (not shown).

[0058] The n is a natural number.

[0059] The n-1th intermediate target layout includes: a plurality of n-1th intermediate target graphics (not shown).

[0060] The n-th intermediate target exposure layout includes: a plurality of n-1th intermediate target exposure patterns, and the plurality of n-1th intermediate target exposure patterns correspond to the plurality of n-1th intermediate target patterns.

[0061] When n=1, the n-1th intermediate target layout is the target layout 200, and the plurality of target graphics 110 are the plurality of n-1th intermediate target graphics; when n>1, the n-1th intermediate target layout is obtained based on the n-1th global optical proximity correction in history, and the plurality of n-1th intermediate target graphics correspond to the plurality of target graphics 110.

[0062] In this embodiment, the nth target layout to be corrected is globally corrected based on the preset model, the target layout 200, and the nth intermediate target exposure layout to form the nth intermediate target layout, including: cutting the contours of several n-1th intermediate target graphics to form several n-1th intermediate target segments; obtaining global edge placement error data between the contours of several n-1th intermediate target exposure graphics and the contours of several target graphics 110; and offsetting several n-1th intermediate target segments according to the global edge placement error data and the preset model to form the nth intermediate target layout.

[0063] In this embodiment, the global edge placement error data includes: a number of edge placement errors between the outline of each (n−1)th intermediate target exposure pattern and the outline of the corresponding target pattern 100 .

[0064] Compared to the local optical proximity correction (OPC) described later, the global OPC performs a global exposure process on the (n-1) intermediate target layout (not shown). It uses a pre-set model that addresses more defect types, includes more boundary conditions, and is more complex. The local OPC described later further corrects EPE defects that may appear in a subsequently formed initial correction layout (formed based on the initial layout 300 formed by the global OPC).

[0065] In this embodiment, the intermediate target layout is used as the target layout to be corrected until several global optical proximity corrections are completed to obtain the initial layout 300, including: when the number of corrections of the global optical proximity correction reaches a preset number k, the global optical proximity correction is stopped, and the k-th intermediate target layout is used as the initial layout 300, where k is a natural number greater than or equal to n.

[0066] Specifically, after performing a preset number (k times) of global optical proximity corrections, an initial layout 300 (ie, the kth intermediate target layout) is formed.

[0067] Accordingly, in this embodiment, the method for offsetting a number of n-1th intermediate target fragments according to the global edge placement error data and the preset model includes: when the global edge placement error data exceeds the preset global error range, offsetting part or all of the number of n-1th intermediate target fragments; when the global edge placement error data is within the preset global error range, not offsetting the number of n-1th intermediate target fragments (that is, the offset distance is 0 nanometers).

[0068] In some other embodiments, the intermediate target layout is used as the target layout to be corrected until several global optical proximity corrections are completed to obtain an initial layout, including: cutting the contours of several n-1th intermediate target graphics to form several n-1th intermediate target segments; obtaining global edge placement error data between the contours of several n-1th intermediate target exposure graphics and the contours of several target graphics 110; when the global edge placement error data between the contours of several n-1th intermediate target exposure graphics and the contours of several target graphics are within a preset global error range, ending the global optical proximity correction and using the n-1th intermediate target layout as the initial layout; when the global edge placement error data exceeds the preset global error range, offsetting part or all of the n-1th intermediate target segments to form the nth intermediate target graphics.

[0069] Please refer to Figure 8 , performing exposure processing on the initial layout to obtain an initial exposure layout 400.

[0070] The initial exposure layout 400 includes: a plurality of initial exposure patterns 410 corresponding to the plurality of initial patterns 310 .

[0071] Please refer to Figure 9 , comparing the initial exposure layout 400 with the target layout 200 , obtaining a number of defects (not shown) in the initial exposure layout 400 , and obtaining a number of edge placement errors corresponding to the defects.

[0072] It should be noted that, for ease of understanding and explanation, Figure 9 In FIG. 2 , the outline of a portion of the target graphic 210 is schematically indicated by a dotted line.

[0073] In this embodiment, the method of comparing the initial exposure layout 400 with the target layout 200, obtaining a plurality of defects in the initial exposure layout 400, and obtaining a plurality of edge placement errors corresponding to the plurality of defects includes: obtaining a plurality of edge placement errors based on contour deviations between a plurality of target patterns 210 and a plurality of initial exposure patterns 410; when any edge placement error among the plurality of edge placement errors exceeds a preset deviation range, determining that a defect is detected, and using the arbitrary edge placement error as the edge placement error corresponding to the defect.

[0074] Next, according to the plurality of edge placement errors, a plurality of graphics to be offset are obtained from the plurality of initial graphics 310. For detailed steps of obtaining a plurality of graphics to be offset from the plurality of initial graphics 310 according to the plurality of edge placement errors, please refer to Figure 10 and Figure 11 .

[0075] Please refer to Figure 10 According to the edge placement errors corresponding to the defects, corresponding line segments 312 to be corrected are obtained in the initial graphics 310 .

[0076] In this embodiment, the method for obtaining the corresponding line segments 312 to be corrected in the initial graphics 310 includes: segmenting the contours of the initial graphics 310 to form a plurality of initial segments 311 (such as Figure 10 According to a plurality of edge placement errors corresponding to a plurality of defects, a plurality of line segments 312 to be corrected are determined in a plurality of initial segments 311.

[0077] It should be noted that, for ease of understanding and explanation, Figure 10 In the outline of the initial graphic 310, the line segment 312 to be corrected is represented by a solid line, and the initial segment 311 which is not the line segment 312 to be corrected is represented by a dotted line.

[0078] In this embodiment, the method for determining a number of to-be-corrected line segments 312 in a number of initial segments 311 based on a number of edge placement errors corresponding to a number of defects includes: forming a number of corresponding defect marking graphics (not shown) in the initial layout 300 based on the number of edge placement errors corresponding to the number of defects; and obtaining a number of initial segments 311 in contact with the number of defect marking graphics from the number of initial segments 311, wherein any segment 311 in contact with the defect marking graphics is the to-be-corrected line segment 312.

[0079] Please refer to Figure 11 , obtain a plurality of first designated line segments 312a that meet the preset conditions and a second designated line segment 312b corresponding to each first designated line segment 312a from the plurality of line segments to be modified 312; and convert the plurality of first designated line segments 312a and the plurality of second designated line segments 312b to the plurality of initial graphics 310 (such as Figure 10 ), as several graphics 320 to be offset.

[0080] In this embodiment, the preset conditions include: the edge placement error corresponding to the first designated line segment 312a is greater than zero, the edge placement error corresponding to the second designated line segment 312b is less than zero, and the corresponding first designated line segment 312a and second designated line segment 312b are parallel to each other and correspond to opposite edges in the same target graphic 210.

[0081] Because the edge placement error corresponding to the first designated line segment 312a is greater than zero, and the edge placement error corresponding to the second designated line segment 312b is less than zero under the preset conditions, and the corresponding first and second designated line segments 312a, 312b are parallel to each other and correspond to opposite edges in the same target pattern 210, any corresponding first and second designated line segments 312a, 312b can reduce their corresponding edge placement errors by shifting them in the same direction. Consequently, by performing an overall shift on the initial pattern 310 (i.e., the pattern to be shifted 320) having any corresponding first and second designated line segments 312a, 312b, the risk of EPE defects occurring in the first and second designated line segments 312a, 312b after subsequent local optical proximity correction can be reduced. Thus, the acquisition of the pattern to be shifted 320 is achieved through the preset conditions.

[0082] It should be noted that, for ease of understanding, Figure 11 The outline of a target graphic 210 and the outline of the corresponding initial exposure graphic 410 are schematically represented by dotted lines. The outline of the target graphic 210 includes opposite edges 211 and 212, wherein the edge 211 corresponds to a first designated line segment 312a, and the edge 212 corresponds to a second designated line segment 312b.

[0083] In this embodiment, the preset condition also includes: the absolute value of the edge placement error deviation value | EPE i |=||EPE1 i |-|EPE2 i || Below the preset value, wherein the |EPE1 i | is the absolute value of the edge placement error corresponding to any first specified line segment 312a, the |EPE2 i | is the absolute value of the edge placement error corresponding to the second designated line segment 312b corresponding to the arbitrary first designated line segment 312a. By making the absolute value of the arbitrary designated edge placement error deviation value |EPE i |=||EPE1 i |-|EPE2 i Below the preset value, segments 311 to be corrected that are close to or identical in distance to be offset in the same direction can be further obtained. Therefore, an initial graphic 310 with a higher risk of EPE defects occurring after local optical proximity correction can be obtained. This allows for a more accurate judgment on the acquisition of the graphic 320 to be offset, thereby further improving the accuracy and efficiency of optical proximity correction.

[0084] Preferably, the preset value is 1 nanometer.

[0085] In this embodiment, the figure to be offset 320 where the arbitrary first specified line segment 312a is located also includes: a first line segment 311a and a first in-line protruding line segment (jog) 311c, the first line segment 311a and the arbitrary first specified line segment 312a have the same extension direction and correspond to the same side (side 211) of the target figure 210, and the first in-line protruding line segment 311c connects the arbitrary first specified line segment 312a and the first line segment 311a.

[0086] In this embodiment, the to-be-offset figure 320 where any first designated line segment 312a is located further includes: a second line segment 311b and a second in-line protruding line segment (jog) 311d, wherein the second line segment 311b has the same extension direction as the first designated line segment 312a, and the second line segment 311b and the second designated line segment 312b corresponding to the any first designated line segment 312a correspond to the same side (side 212) of the target figure 210, and the second in-line protruding line segment 311d connects the second line segment 311b and the second designated line segment 312b.

[0087] It should be noted that the jog line segments (jog) are usually not offset during optical proximity correction, but only extended. Their function is to connect the offset fragments in the graphic outline to still form a closed outline graphic after optical proximity correction.

[0088] Please refer to Figure 12 Based on a number of edge placement errors corresponding to each of the patterns to be offset 320 , each of the patterns to be offset 320 is offset to form an initial revised layout 500 .

[0089] It should be noted that, for ease of understanding, Figure 12 In the figure, the unshifted pattern 320 to be shifted is schematically represented by a dotted line.

[0090] After obtaining the initial layout and before performing the subsequent local optical proximity correction, the initial exposure layout 400 is compared with the target layout 200 to obtain a number of defects in the initial exposure layout 400 and a number of edge placement errors corresponding to the defects. Then, based on the number of edge placement errors, a number of to-be-offset patterns 320 are obtained from the number of initial patterns. Moreover, based on the number of edge placement errors corresponding to each of the to-be-offset patterns 320, each of the to-be-offset patterns 320 is offset to form the initial corrected layout 500. Therefore, before the subsequent local optical proximity correction, accurate offset correction is performed on each of the to-be-offset patterns 320. This reduces the risk of segments that need to be offset due to edge placement errors not reaching the expected range being unable to be offset or being stuck due to preset restrictions (e.g., the spacing with surrounding patterns reaches a minimum spacing) in the local optical proximity correction, thereby reducing EPE defects in the local optical proximity correction. Furthermore, the accuracy of subsequent local optical proximity correction is improved, and the pattern transferred from the revised layout formed based on the subsequent optical proximity correction is closer to the target layout 200, thereby improving the graphic accuracy of the revised layout.

[0091] Moreover, since accurate offset correction is performed on each to-be-offset pattern 320 before the subsequent local optical proximity correction, the number of subsequent local optical proximity correction cycles can be reduced, thereby improving the overall correction efficiency of the optical proximity correction.

[0092] In addition, in this embodiment, since the pattern to be offset 320 where any first specified line segment 312a is located also includes the first line segment 311a and the first in-line protruding line segment (jog) 311c, offsetting the pattern to be offset 320 before the subsequent local optical proximity correction can also reduce the length that the first in-line protruding line segment 311c needs to extend in the local optical proximity correction, thereby helping to reduce the degree of protrusion of the outline of the pattern corresponding to the pattern to be offset 320 after the local optical proximity correction. Furthermore, while reducing EPE defects, it is possible to improve the graphic morphology of the corrected layout, so as to better transfer the pattern to the wafer in the lithography process.

[0093] Similarly, in this embodiment, since the pattern to be offset 320 where any second specified line segment 312b is located also includes the first line segment 311b and the protruding line segment (jog) 311d in the second line, it is possible to reduce EPE defects while improving the graphic morphology of the corrected layout, thereby better transferring the pattern to the wafer in the lithography process.

[0094] In this embodiment, based on a number of edge placement errors corresponding to each to-be-shifted graphic 320, a method for shifting each to-be-shifted graphic includes: obtaining an offset distance based on an edge placement error corresponding to any first specified line segment 312a and an edge placement error corresponding to a second specified line segment 312b corresponding to the first specified line segment 312a; shifting the to-be-shifted graphic 320 where the first specified line segment 312a is located along the offset direction X (e.g., Figure 12 ) is offset by the offset distance.

[0095] In this embodiment, the offset distance S=(|EPE1 i |+|EPE2 i |) / 2, where |EPE1 i | is the absolute value of the edge placement error corresponding to the arbitrary first specified line segment 312a, the |EPE2 i | is the absolute value of the edge placement error corresponding to the second designated line segment 312b corresponding to the arbitrary first designated line segment 312a.

[0096] The offset direction X is perpendicular to the extending direction of the arbitrary first designated line segment 312 a and is from the arbitrary first designated line segment 312 a toward the corresponding second designated line segment 312 b .

[0097] It is important to understand that Figure 12 The offset direction X shown in Figure 12 The extending directions and positions of the first designated line segment 312a and the second designated line segment 312b are shown in FIG.

[0098] Specifically, the initial revised layout 500 includes: a plurality of initial revised graphics 510 corresponding to a plurality of target graphics 210 .

[0099] The plurality of initial modified graphics 510 include: a plurality of unshifted initial graphics 310 and a plurality of shifted graphics 320 to be shifted.

[0100] Please refer to Figure 13 , performing several local optical proximity corrections on the initial revised layout 500 to obtain a revised layout 600 .

[0101] The revised layout 600 includes a plurality of revised graphics 610 corresponding to a plurality of target graphics 210 .

[0102] The local optical proximity correction is used to correct the EPE defects in the initial correction pattern 510.

[0103] In this embodiment, performing several local optical proximity corrections on the initial revised layout 500 to obtain a revised layout 600 includes: using the initial revised layout 500 as an intermediate layout to be corrected (not shown) and performing exposure processing to obtain an intermediate corrected exposure layout (not shown); forming an intermediate revised layout (not shown) based on the target layout 200, the intermediate layout to be corrected, and the intermediate corrected exposure layout; using the intermediate revised layout as the intermediate layout to be corrected, and continuing to perform local optical proximity corrections until several local optical proximity corrections are completed to obtain the revised layout 600.

[0104] In this embodiment, the intermediate layout to be corrected includes a plurality of intermediate correction patterns (not shown).

[0105] It should be understood that when the initial revised layout 500 is used as the intermediate layout to be revised, the intermediate revised graphics included in the intermediate layout to be revised are the initial revised graphics 510 .

[0106] In this embodiment, the intermediate correction exposure pattern includes a plurality of intermediate correction exposure patterns (not shown).

[0107] In this embodiment, the intermediate correction layout is formed based on the target layout 200, the intermediate layout to be corrected, and the intermediate correction exposure layout, including: obtaining a plurality of defects and corresponding edge placement errors of the intermediate correction exposure layout based on the contour deviations between a plurality of intermediate correction exposure patterns and a plurality of target patterns 210; segmenting the contours of the plurality of intermediate correction patterns to form a plurality of intermediate correction segments (not shown); obtaining a plurality of corresponding intermediate line segments to be corrected (not shown) in the plurality of intermediate correction segments based on the plurality of edge placement errors corresponding to the plurality of defects of the intermediate correction exposure layout; and offsetting a plurality of intermediate line segments to be corrected based on the plurality of edge placement errors corresponding to the plurality of defects of the intermediate correction exposure layout to form an intermediate correction layout (not shown).

[0108] Specifically, the method for performing the mth local optical proximity correction includes: using the m-1th intermediate correction layout (not shown) as the mth intermediate layout to be corrected, and performing exposure processing to obtain the mth intermediate correction exposure layout (not shown); forming the mth intermediate correction layout (not shown) according to the target layout 200, the mth intermediate layout to be corrected, and the mth intermediate correction exposure layout.

[0109] The m is a natural number.

[0110] The (m-1)th intermediate revision layout includes: a plurality of (m-1)th intermediate revision patterns (not shown) corresponding to the plurality of target patterns 210 .

[0111] When m=1, the (m-1)th intermediate revised layout is the initial revised layout 500 , and the (m-1)th intermediate revised patterns are the initial revised patterns 510 .

[0112] The m-th intermediate correction exposure pattern includes: a plurality of intermediate correction exposure patterns (not shown) corresponding to the m-1-th intermediate correction patterns.

[0113] Specifically, the method of forming the mth intermediate correction layout based on the target layout 200, the mth intermediate correction layout and the mth intermediate correction exposure layout includes: obtaining a number of defects and corresponding edge placement errors of the mth intermediate correction exposure layout based on a number of intermediate correction exposure patterns corresponding to the m-1th intermediate correction patterns and a contour deviation between the target patterns 210; dividing the contours of the m-1th intermediate correction patterns to form a number of m-1th intermediate correction segments (not shown); obtaining a number of mth intermediate line segments to be corrected in a number of m-1th intermediate correction segments (not shown) based on a number of edge placement errors corresponding to a number of defects of the mth intermediate correction exposure layout; and offsetting a number of intermediate line segments to be corrected based on a number of edge placement errors corresponding to a number of defects of the mth intermediate correction exposure layout to form the mth intermediate correction layout.

[0114] In this embodiment, the m-1th intermediate revised layout is used as the mth intermediate layout to be revised, and exposure processing is performed to obtain the mth intermediate revised exposure layout, including: when m=1, performing global exposure processing on the mth intermediate layout to be revised; when m>1, performing local exposure on the exposure area (shot) where several intermediate line segments to be revised of the mth are located.

[0115] Therefore, during the initial local optical proximity correction, all EPE defects that need to be corrected can be determined, and in the subsequent local optical proximity corrections, the correction efficiency can be improved, thereby better balancing correction accuracy and correction efficiency.

[0116] In this embodiment, the method of using the intermediate revised layout as the intermediate layout to be revised and continuing to perform local optical proximity correction until a number of local optical proximity corrections are completed to obtain the revised layout 600 further includes: when the number of corrections of the local optical proximity correction reaches a preset number g, stopping the local optical proximity correction, and using the g-th intermediate revised layout as the revised layout 600, where g is a natural number greater than or equal to m.

[0117] Specifically, in this embodiment, after performing a preset number (g times) of local optical proximity corrections, a correction layout 600 (ie, the g-th intermediate correction layout) is formed.

[0118] In this embodiment, the optical proximity correction method further includes: when the graphics to be offset 320 cannot be obtained in the initial graphics 210 (that is, the number of graphics to be offset 320 is 0) based on the edge placement errors, performing several local optical proximity corrections on the initial layout 300.

[0119] Specifically, when the plurality of line segments 312 to be corrected do not include the first designated line segment 312 a and the second designated line segment 312 b that meet the preset condition, the initial layout 300 is directly subjected to a plurality of local optical proximity corrections.

[0120] 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 scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. An optical proximity correction method, characterized in that: include: Providing a target layout, wherein the target layout includes a plurality of target graphics; Acquire an initial layout, wherein the initial layout includes a plurality of initial graphics corresponding to the plurality of target graphics; Performing exposure processing on the initial layout to obtain an initial exposure layout; Comparing the initial exposure layout with the target layout, obtaining a number of defects in the initial exposure layout, and obtaining a number of edge placement errors corresponding to the number of defects; Acquire a plurality of graphics to be offset from a plurality of initial graphics according to the plurality of edge placement errors; Based on a number of edge placement errors corresponding to each of the patterns to be offset, offset each of the patterns to be offset to form an initial corrected layout; Performing several local optical proximity corrections on the initial revised layout to obtain a revised layout; Among them, the method of obtaining several graphics to be offset in several initial graphics based on the several edge placement errors includes: obtaining several corresponding line segments to be corrected in several initial graphics based on the several edge placement errors corresponding to the several defects; obtaining several first specified line segments that meet preset conditions and second specified line segments corresponding to each first specified line segment among the several line segments to be corrected; and using the several initial graphics where the several first specified line segments and the several second specified line segments are located as several graphics to be offset.

2. The optical proximity correction method according to claim 1, wherein: The preset conditions include: the edge placement error corresponding to the first specified line segment is greater than zero, the edge placement error corresponding to the second specified line segment is less than zero, and the corresponding first specified line segment and second specified line segment are parallel to each other and correspond to opposite edges in the same target graphic.

3. The optical proximity correction method according to claim 2, wherein: The preset conditions also include: the absolute value of any specified edge placement error deviation value | EPE i |=||EPE1 i |-|EPE2 i || Below the preset value, wherein the |EPE1 i | is the absolute value of the edge placement error corresponding to any first specified line segment, the |EPE2 i | is the absolute value of the edge placement error corresponding to the second designated line segment corresponding to the arbitrary first designated line segment.

4. The optical proximity correction method according to claim 3, wherein: The preset value is 1 nanometer.

5. The optical proximity correction method according to claim 1, wherein: The method of obtaining corresponding line segments to be corrected in the initial graphics includes: Segmenting the outlines of several initial graphics to form several initial segments; A plurality of line segments to be corrected are determined in the plurality of initial segments according to a plurality of edge placement errors corresponding to the plurality of defects.

6. The optical proximity correction method according to claim 1, wherein: The figure to be offset where any first specified line segment is located also includes: a first line segment and a protruding line segment within the first line, the first line segment and the any first specified line segment have the same extension direction and correspond to the same side of the target figure, and the protruding line segment within the first line connects the any first specified line segment and the first line segment.

7. The optical proximity correction method according to claim 6, wherein: The figure to be offset where any first specified line segment is located also includes: a second line segment and a protruding line segment within the second line, the second line segment has the same extension direction as the first specified line segment, and the second line segment and the second specified line segment corresponding to the any first specified line segment correspond to the same side of the target figure, and the protruding line segment within the second line connects the second line segment and the second specified line segment.

8. The optical proximity correction method according to claim 1, wherein: Based on a number of edge placement errors corresponding to each of the graphics to be offset, a method for offsetting each of the graphics to be offset includes: Obtaining an offset distance according to an edge placement error corresponding to any first designated line segment and an edge placement error corresponding to a second designated line segment corresponding to the any first designated line segment; The to-be-offset figure where the arbitrary first designated line segment is located is offset by the offset distance along an offset direction, where the offset direction is perpendicular to the extension direction of the arbitrary first designated line segment and is from the arbitrary first designated line segment toward the corresponding second designated line segment.

9. The optical proximity correction method according to claim 8, wherein: The offset distance S=(|EPE1 i |+|EPE2 i |) / 2, where |EPE1 i | is the absolute value of the edge placement error corresponding to the arbitrary first specified line segment, the |EPE2 i | is the absolute value of the edge placement error corresponding to the second designated line segment corresponding to the arbitrary first designated line segment.

10. The optical proximity correction method according to claim 1, wherein: The initial exposure layout includes: a plurality of initial exposure patterns corresponding to the plurality of initial patterns; The method of comparing the initial exposure layout with the target layout, obtaining a plurality of defects in the initial exposure layout, and obtaining a plurality of edge placement errors corresponding to the plurality of defects includes: Obtaining a plurality of edge placement errors according to contour deviations between a plurality of target patterns and a plurality of initial exposure patterns; When any edge placement error among the plurality of edge placement errors exceeds a preset deviation range, it is determined that a defect is detected, and the any edge placement error is used as the edge placement error corresponding to the defect.

11. The optical proximity correction method according to claim 1, wherein: The obtaining of the initial layout includes: performing a plurality of global optical proximity corrections on the target layout to obtain the initial layout.

12. The optical proximity correction method according to claim 11, wherein: The step of performing a plurality of global optical proximity corrections on the target layout to obtain an initial layout includes: Taking the target layout as the target layout to be corrected, and performing exposure processing to obtain an intermediate target exposure layout; Performing global correction processing on the target layout to be corrected according to a preset model, the target layout and the intermediate target exposure layout to generate an intermediate target layout; The intermediate target layout is used as the target layout to be corrected until several global optical proximity corrections are completed to obtain an initial layout.

13. The optical proximity correction method according to claim 1, wherein: The performing several local optical proximity corrections on the initial revised layout to obtain a revised layout includes: Using the initial revised layout as an intermediate layout to be revised, and performing exposure processing to obtain an intermediate revised exposure layout; forming an intermediate revised layout according to the target layout, the intermediate layout to be revised, and the intermediate revised exposure layout; The intermediate corrected layout is used as the intermediate layout to be corrected, and local optical proximity correction is continued until several local optical proximity corrections are completed to obtain a corrected layout.

14. The optical proximity correction method according to claim 13, wherein: The intermediate to-be-corrected layout includes a plurality of intermediate correction patterns, and the intermediate correction exposure layout includes a plurality of intermediate correction exposure patterns; The step of forming an intermediate revised layout according to the target layout, the intermediate layout to be revised, and the intermediate revised exposure layout comprises: Obtaining a plurality of defects of the intermediate corrected exposure pattern and a corresponding plurality of edge placement errors according to contour deviations between the plurality of intermediate corrected exposure patterns and the plurality of target patterns; Segmenting the contours of a plurality of intermediate correction figures to form a plurality of intermediate correction segments; According to a plurality of edge placement errors corresponding to a plurality of defects of the intermediate corrected exposure pattern, obtaining a corresponding plurality of intermediate line segments to be corrected in the plurality of intermediate corrected segments; According to a plurality of edge placement errors corresponding to a plurality of defects of the intermediate correction exposure pattern, a plurality of the intermediate line segments to be corrected are offset to form an intermediate correction pattern.

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