Graphic correction methods

Abstract

A pattern correction method includes: providing a pattern to be corrected, the pattern including a plurality of patterns to be corrected; exposing and developing the pattern to be corrected to obtain a photolithographic pattern, the photolithographic pattern including a plurality of photolithographic patterns, each photolithographic pattern corresponding to one of the patterns to be corrected; obtaining a three-dimensional contour of the photolithographic patterns; determining whether the sidewalls of the three-dimensional contour have shifted; based on whether the sidewalls of the three-dimensional contour have shifted, obtaining a first pattern and a second pattern, the first pattern being a pattern to be corrected that does not require correction, and the second pattern being a pattern to be corrected other than the first pattern; and performing optical proximity effect correction on the second pattern. The method improves correction efficiency.

Description

Technical Field

[0001] This invention relates to the field of semiconductors, and more particularly to a pattern correction method. Background Technology

[0002] To transfer a pattern from a photomask to the surface of a silicon wafer, the process typically involves an exposure step, a development step following the exposure step, and an etching step following the development step. 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 utilized 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] As device feature sizes continue to shrink, the patterns projected onto the photoresist layer become significantly distorted and deformed. Calibration of these correction models requires the acquisition of the three-dimensional contour features of the photoresist. Summary of the Invention

[0006] The technical problem solved by this invention is to provide a graphic correction method to improve graphic correction efficiency.

[0007] To address the aforementioned technical problems, the present invention provides a pattern correction method, comprising: providing a pattern to be corrected, the pattern including a plurality of patterns to be corrected; exposing and developing the pattern to be corrected to obtain a photolithographic pattern, the photolithographic pattern including a plurality of photolithographic patterns, the photolithographic patterns corresponding one-to-one with the patterns to be corrected; obtaining a three-dimensional contour of the photolithographic patterns; determining whether the sidewalls of the three-dimensional contour have shifted; based on whether the sidewalls of the three-dimensional contour have shifted, obtaining a first pattern and a second pattern, the first pattern being a pattern to be corrected that does not require correction, and the second pattern being a pattern to be corrected other than the first pattern; and performing optical proximity effect correction on the second pattern.

[0008] Optionally, the method for determining whether the sidewalls of the three-dimensional contour have shifted includes: obtaining a plurality of equipotential lines between the sidewalls of adjacent three-dimensional contours, wherein the plurality of equipotential lines are parallel to the surface of the photolithography pattern; obtaining the length difference between the longest and shortest equipotential lines among the plurality of equipotential lines; and determining whether the sidewalls of the three-dimensional contour have shifted based on whether the absolute value of the length difference is within a preset range.

[0009] Optionally, the sidewall of the three-dimensional contour is determined to have shifted based on whether the absolute value of the length difference is within a preset range: if the absolute value of the length difference is not within the preset range, the sidewall of the three-dimensional contour is determined to have shifted; if the absolute value of the length difference is within the preset range, the sidewall of the three-dimensional contour is determined not to have shifted.

[0010] Optionally, the method for obtaining the first and second images includes: if the sidewalls of the three-dimensional contour have shifted, the image to be corrected corresponding to the three-dimensional contour does not need to be corrected for optical proximity effect, and the first image is obtained; if the sidewalls of the three-dimensional contour have not shifted, the image to be corrected corresponding to the three-dimensional contour needs to be corrected for optical proximity effect, and the second image is obtained.

[0011] Optionally, the method for optical proximity correction of the second graphic includes: obtaining the edge placement error between the second graphic and the corresponding three-dimensional contour; determining whether the edge placement error within a preset area of ​​the three-dimensional contour is within a preset range; and determining whether the second graphic area corresponding to the preset area of ​​the three-dimensional contour needs optical proximity correction based on whether the edge placement error within the preset area of ​​the three-dimensional contour is within a preset range.

[0012] Optionally, the method for determining whether the second graphic region corresponding to the three-dimensional contour preset region needs optical proximity effect correction based on whether the edge placement error within the three-dimensional contour preset region is within a preset range includes: if there are more than a first preset proportion of edge placement errors within the three-dimensional contour preset region that are within a preset value range, then the second graphic region corresponding to the three-dimensional contour preset region does not need optical proximity effect correction; if there are more than a second preset proportion of edge placement errors within the three-dimensional contour preset region that exceed a preset value range, then the second graphic region corresponding to the three-dimensional contour preset region needs optical proximity effect correction.

[0013] Optionally, the preset value ranges from 2% to 7% of the feature size.

[0014] Optionally, the first preset ratio is 80%; the second preset ratio is 20%.

[0015] Optionally, the method for obtaining the edge placement error between the second graphic and the corresponding three-dimensional contour includes: obtaining several projection graphics of the three-dimensional contour on the surface of the photolithography plate; obtaining a target graphic among the several projection graphics, wherein the target graphic corresponds to the second graphic; cutting the contour of the target graphic into several line segments; and obtaining several edge placement errors between the several line segments and the contour lines of the corresponding second corrected graphic.

[0016] Optionally, methods for obtaining the three-dimensional contour of the lithographic pattern include: using an atomic force microscope to obtain the three-dimensional contour of the lithographic pattern.

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

[0018] The technical solution of the present invention obtains the three-dimensional contour of the photolithographic pattern, first determines whether the sidewalls of the three-dimensional contour have shifted, and then obtains the second pattern to be corrected from the pattern to be corrected based on whether the sidewalls of the three-dimensional contour have shifted, thereby reducing the correction range and improving the efficiency and accuracy of optical proximity effect correction.

[0019] Furthermore, an atomic force microscope is used to obtain the three-dimensional contour of the lithographic pattern. By obtaining the three-dimensional contour of the lithographic pattern, the internal features of the pattern can be observed, thereby enabling effective analysis of the causes of lithographic pattern distortion and accurate correction of optical proximity effects. Attached Figure Description

[0020] Figures 1 to 4 This is a flowchart illustrating the graphic correction method in an embodiment of the present invention;

[0021] Figures 5 to 7 This is a schematic diagram of the photolithographic pattern in an embodiment of the present invention. Detailed Implementation

[0022] 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.

[0023] Figures 1 to 4 This is a flowchart illustrating the graphic correction method in an embodiment of the present invention.

[0024] Please refer to Figure 1 The graphic correction method includes:

[0025] Step S10: Provide a layout to be corrected, the layout to be corrected including a plurality of graphics to be corrected;

[0026] Step S20: Expose and develop the pattern to be corrected to obtain a photolithography pattern, wherein the photolithography pattern includes a plurality of photolithography patterns, and the photolithography patterns correspond one-to-one with the pattern to be corrected;

[0027] Step S30: Obtain the three-dimensional contour of the photolithographic pattern;

[0028] Step S40: Determine whether the sidewalls of the three-dimensional contour have shifted;

[0029] Step S50: Based on whether the sidewalls of the three-dimensional contour have shifted, obtain a first graphic and a second graphic. The first graphic is a graphic to be corrected that does not require correction, and the second graphic is a graphic to be corrected other than the first graphic.

[0030] Step S60: Perform optical proximity correction on the second pattern.

[0031] The method obtains the three-dimensional contour of the photolithographic pattern, first determines whether the sidewalls of the three-dimensional contour have shifted, and then, based on whether the sidewalls of the three-dimensional contour have shifted, obtains the second pattern that needs to be corrected from the pattern to be corrected, thereby reducing the correction range and improving the efficiency and accuracy of optical proximity effect correction.

[0032] Next, each step will be analyzed and explained.

[0033] Please continue to refer to this. Figure 1 Step S10: Provide a layout to be corrected, the layout to be corrected including several graphics to be corrected.

[0034] The pattern to be corrected is a mask pattern that needs to be corrected by optical proximity effect.

[0035] Please continue to refer to this. Figure 1 Step S20: Expose and develop the pattern to be corrected to obtain a photolithography pattern, wherein the photolithography pattern includes several photolithography patterns, and the photolithography patterns correspond one-to-one with the pattern to be corrected.

[0036] The photolithographic pattern of the photolithography pattern is a photoresist pattern.

[0037] Please continue to refer to this. Figure 1 Step S30: Obtain the three-dimensional contour of the lithographic pattern.

[0038] Methods for obtaining the three-dimensional contour of a photolithographic pattern include: using an atomic force microscope to obtain the three-dimensional contour of the photolithographic pattern.

[0039] The working principle of atomic force microscopy (AFM) is as follows: A microcantilever, extremely sensitive to minute forces, is fixed at one end, with a tiny needle tip at the other. The needle tip gently contacts the sample surface. Due to the extremely weak repulsive force between the atoms at the needle tip and those on the sample surface, by controlling this force to remain constant during scanning, the microcantilever with the needle tip will undulate perpendicularly to the sample surface, corresponding to the equipotential surfaces of the forces between the needle tip and the sample surface atoms. Using optical detection or tunneling current detection, the positional changes of the microcantilever at various scanning points can be measured, thereby obtaining information about the sample surface morphology.

[0040] By acquiring the three-dimensional contour of the lithographic pattern, the internal features of the lithographic pattern can be observed, thereby enabling effective analysis of the causes of lithographic pattern distortion and accurate correction of optical proximity effect.

[0041] Please continue to refer to this. Figure 1 Step S40: Determine whether the sidewalls of the three-dimensional contour have shifted.

[0042] Please refer to Figure 2 In this embodiment, the method for determining whether the sidewalls of the three-dimensional contour have shifted includes:

[0043] Step S401: Obtain a plurality of equipotential lines between the sidewalls of adjacent three-dimensional contours, wherein the plurality of equipotential lines are parallel to the surface of the photolithography pattern.

[0044] Step S402: Obtain the length difference between the longest and shortest equipotential lines among several equipotential lines;

[0045] Step S403: Determine whether the sidewall of the three-dimensional contour has shifted based on whether the absolute value of the length difference is within a preset range.

[0046] The sidewalls of the three-dimensional contour are determined to have shifted based on whether the absolute value of the length difference is within a preset range: if the absolute value of the length difference is not within the preset range, the sidewalls of the three-dimensional contour are determined to have shifted; if the absolute value of the length difference is within the preset range, the sidewalls of the three-dimensional contour are determined not to have shifted.

[0047] Please refer to Figures 5 to 7 , Figures 5 to 7This is a schematic diagram of different morphological shapes of the three-dimensional contour sidewalls of a photolithographic pattern, which is located on wafer 100. Figure 5 The absolute value of the length difference between the longest equipotential line L1 and the shortest equipotential line L1 among several equipotential lines L1 between the three-dimensional contour sidewalls of the photolithographic pattern 101 is within a preset range. Figure 6 The absolute value of the length difference between the longest equipotential line L2 and the shortest equipotential line L2 among several equipotential lines L2 between the three-dimensional contour sidewalls of the photolithography pattern 201 is not within the preset range. Figure 7 The absolute value of the length difference between the longest equipotential line L3 and the shortest equipotential line L3 among several equipotential lines L3 between the three-dimensional contour sidewalls of the photolithographic pattern 301 is not within the preset range.

[0048] Please continue to refer to this. Figure 1 Step S50: Based on whether the sidewalls of the three-dimensional contour have shifted, obtain a first graphic and a second graphic. The first graphic is a graphic to be corrected that does not require correction, and the second graphic is a graphic to be corrected other than the first graphic.

[0049] The method for obtaining the first and second images includes: if the sidewalls of the three-dimensional contour have shifted, the image to be corrected corresponding to the three-dimensional contour does not need to be corrected for optical proximity effect, and the first image is obtained; if the sidewalls of the three-dimensional contour have not shifted, the image to be corrected corresponding to the three-dimensional contour needs to be corrected for optical proximity effect, and the second image is obtained.

[0050] The material for the photolithographic pattern is photoresist, and the photoacid in the photoresist diffuses unevenly in different directions. If the absolute value of the length difference is not within a preset range, it indicates that the photoresist is severely distorted (e.g., ...). Figure 6 and Figure 7 If the lithographic pattern distortion is caused by the photoresist itself, then the pattern to be corrected corresponding to the three-dimensional contour does not need optical proximity effect correction. If the absolute value of the length difference is within a preset range, it indicates that the photoresist distortion is within an acceptable range. If the lithographic pattern distortion is caused by optical proximity effect, then the pattern to be corrected corresponding to the three-dimensional contour needs optical proximity effect correction.

[0051] Based on whether the sidewalls of the three-dimensional profile have shifted, a second image that needs to be corrected is obtained from the image to be corrected, thereby reducing the correction range and improving the efficiency of optical proximity effect correction.

[0052] Please continue to refer to this. Figure 1 Step S60: Perform optical proximity effect correction on the second pattern.

[0053] Please refer to Figure 3In this embodiment, the method for correcting the optical proximity effect of the second pattern includes:

[0054] Step S601: Obtain the edge placement error between the second graphic and the corresponding 3D contour;

[0055] Step S602: Determine whether the edge placement error within the preset area of ​​the three-dimensional contour is within the preset range;

[0056] Step S603: Based on whether the edge placement error within the preset area of ​​the three-dimensional contour is within the preset range, determine whether the second graphic area corresponding to the preset area of ​​the three-dimensional contour needs to be corrected for optical proximity effect.

[0057] The method for determining whether the second graphic region corresponding to the three-dimensional contour preset region needs optical proximity effect correction based on whether the edge placement error within the preset region of the three-dimensional contour is within a preset range includes: if there are more than a first preset proportion of edge placement errors within the preset region of the three-dimensional contour preset region that are within a preset value range, then the second graphic region corresponding to the three-dimensional contour preset region does not need optical proximity effect correction; if there are more than a second preset proportion of edge placement errors within the preset region of the three-dimensional contour preset region that exceed a preset value range, then the second graphic region corresponding to the three-dimensional contour preset region needs optical proximity effect correction.

[0058] The preset area of ​​the three-dimensional contour is selected according to actual needs, and can be the corner, the angle, or the end of the line of the three-dimensional contour.

[0059] In this embodiment, the first preset ratio is 80%; the second preset ratio is 20%.

[0060] In this embodiment, the preset value ranges from 2% to 7% of the feature size. The feature size is determined based on the actual layout.

[0061] Please refer to Figure 4 In this embodiment, the method for obtaining the edge placement error between the second graphic and the corresponding three-dimensional contour includes:

[0062] Step S6011: Obtain several projection graphics of the three-dimensional contour on the surface of the photolithography pattern;

[0063] Step S6012: Obtain the target graphic from a plurality of projected graphics, wherein the target graphic corresponds to the second graphic;

[0064] Step S6013: Cut the outline of the target graphic into several line segments;

[0065] Step S6014: Obtain several edge placement errors between several line segments and the corresponding second corrected graphic outline.

[0066] The target graphic corresponds to the second graphic, that is, the coordinates of the target graphic on the photolithography pattern correspond to the coordinates of the second graphic on the pattern to be corrected.

[0067] 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. A method for correcting graphics, characterized in that, include: A layout to be corrected is provided, the layout to be corrected including several graphics to be corrected; The pattern to be corrected is exposed and developed to obtain a photolithography pattern, which includes several photolithography patterns, and each photolithography pattern corresponds one-to-one with the pattern to be corrected. Obtain the three-dimensional contour of the photolithographic pattern; The method for determining whether the sidewalls of the three-dimensional contour have shifted includes: obtaining a plurality of equipotential lines between the sidewalls of adjacent three-dimensional contours, wherein the plurality of equipotential lines are parallel to the surface of the photolithography pattern; obtaining the length difference between the longest and shortest equipotential lines among the plurality of equipotential lines; and determining whether the sidewalls of the three-dimensional contour have shifted based on whether the absolute value of the length difference is within a preset range. Based on whether the sidewalls of the three-dimensional contour have shifted, a first image and a second image are obtained. The first image is a correction image that does not require correction, and the second image is a correction image other than the first image. The first image is a correction image where the sidewalls of the three-dimensional contour have shifted, and the second image is a correction image where the sidewalls of the three-dimensional contour have not shifted. The second pattern is corrected for optical proximity effect.

2. The graphic correction method as described in claim 1, characterized in that, The sidewalls of the three-dimensional contour are determined to have shifted based on whether the absolute value of the length difference is within a preset range: if the absolute value of the length difference is not within the preset range, the sidewalls of the three-dimensional contour are determined to have shifted; if the absolute value of the length difference is within the preset range, the sidewalls of the three-dimensional contour are determined not to have shifted.

3. The graphic correction method as described in claim 2, characterized in that, The method for obtaining the first and second images includes: if the sidewalls of the three-dimensional contour have shifted, the image to be corrected corresponding to the three-dimensional contour does not need to be corrected for optical proximity effect, and the first image is obtained; if the sidewalls of the three-dimensional contour have not shifted, the image to be corrected corresponding to the three-dimensional contour needs to be corrected for optical proximity effect, and the second image is obtained.

4. The graphic correction method as described in claim 1, characterized in that, The method for optical proximity correction of the second graphic includes: obtaining the edge placement error between the second graphic and the corresponding three-dimensional contour; determining whether the edge placement error within a preset area of ​​the three-dimensional contour is within a preset range; and determining whether the second graphic area corresponding to the preset area of ​​the three-dimensional contour needs optical proximity correction based on whether the edge placement error within the preset area of ​​the three-dimensional contour is within a preset range.

5. The graphic correction method as described in claim 4, characterized in that, The method for determining whether the second graphic region corresponding to the three-dimensional contour preset region needs optical proximity effect correction based on whether the edge placement error within the preset region of the three-dimensional contour is within a preset range includes: if there are more than a first preset proportion of edge placement errors within the preset region of the three-dimensional contour preset region that are within a preset value range, then the second graphic region corresponding to the three-dimensional contour preset region does not need optical proximity effect correction; if there are more than a second preset proportion of edge placement errors within the preset region of the three-dimensional contour preset region that exceed a preset value range, then the second graphic region corresponding to the three-dimensional contour preset region needs optical proximity effect correction.

6. The graphic correction method as described in claim 5, characterized in that, The preset value range is 2% to 7% of the feature size.

7. The graphic correction method as described in claim 5, characterized in that, The first preset ratio is 80%; the second preset ratio is 20%.

8. The graphic correction method as described in claim 4, characterized in that, The method for obtaining the edge placement error between the second graphic and the corresponding three-dimensional contour includes: obtaining several projection graphics of the three-dimensional contour on the surface of the photolithography plate; obtaining a target graphic among the several projection graphics, wherein the target graphic corresponds to the second graphic; cutting the contour of the target graphic into several line segments; and obtaining several edge placement errors between the several line segments and the contour lines of the corresponding second graphic.

9. The graphic correction method as described in claim 1, characterized in that, Methods for obtaining the three-dimensional contour of a photolithographic pattern include: using an atomic force microscope to obtain the three-dimensional contour of the photolithographic pattern.

Images