Method for distinguishing OPC (Optical Proximity Correction) graph line width report errors

Abstract

The invention provides a method for distinguishing OPC (Optical Proximity Correction) graph line width report errors, which comprises the following steps of: generating a target contrast graph based on a target graph and OPC inward correction maximum values, performing OPC on the target graph to obtain an OPC graph, performing mask rule check on the OPC graph to generate line width report errors, and judging the intersection of the line width report errors and the target contrast graph to distinguish the line width report errors of the OPC graph. The false line width error caused by the zigzag edge of the OPC correction graph is rapidly distinguished and identified, the false line width error processing time is saved, and the integrated circuit design period is shortened.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing and relates to a method for distinguishing OPC correction pattern linewidth errors. Background Technology

[0002] Optical Proximity Correction (OPC) is a key technology in semiconductor manufacturing, used to correct pattern distortion caused by optical diffraction and proximity effects during photolithography, ensuring that the final pattern matches the design. After performing OPC correction on the target pattern, OPC Verify (OPCV) is required to check the effectiveness of the OPC correction, identify potential defects such as bridges, pins, and linewidth variations, and ensure process window compatibility, guaranteeing that the OPC-corrected mask will not cause defects in subsequent process flows.

[0003] like Figure 1 As shown, after OPC correction of target graphic 1, OPC corrected graphic 3 is obtained. OPC corrected graphic 3 has "jagged" edges. When performing mask rule check (MRC) on OPC corrected graphic 3, an error will occur because it does not meet the minimum linewidth limit. In addition to the real error 30, which has a significant impact on the etching pattern, the "jagged" edges will also cause linewidth errors due to not meeting the minimum linewidth limit. However, the linewidth errors of the "jagged" edges of OPC corrected graphic 3 have a low impact on the etching pattern, forming a false error 31. Currently, false errors 31 need to be identified manually by engineers. Processing false errors 31 one by one will waste a lot of time and reduce efficiency.

[0004] Therefore, how to provide a method to distinguish between real and false errors in OPC correction graphics line width, and avoid wasting time processing false errors, has become an urgent problem for those skilled in the art. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a method for distinguishing the types of OPC correction graphic linewidth error reports, in order to solve the problem of low efficiency caused by the inability to quickly distinguish false errors in linewidth error reports in the prior art.

[0006] To achieve the above and other related objectives, this invention provides a method for distinguishing OPC correction graphic linewidth errors, comprising the following steps:

[0007] Provide a target graphic and obtain the maximum inward correction value when the target graphic undergoes OPC correction;

[0008] Based on the inward correction maximum value, a target reference image of the target image is obtained, wherein the target reference image is smaller than the target image;

[0009] The target graphic is modified using OPC to obtain an OPC-corrected graphic;

[0010] According to the masking rules, the line width error of the OPC correction graphic is obtained;

[0011] The type of line width error is determined. If the position of the line width error intersects with the target reference graphic, it is determined to be a real error. If the position of the line width error does not intersect with the target reference graphic, it is determined to be a false error.

[0012] Optionally, the linewidth error includes portions of the OPC correction pattern that do not conform to the minimum linewidth limit in the mask rules.

[0013] Optionally, the target graphic is a rectangle, and the ratio between the length of the short side of the target graphic and the maximum inward correction value is greater than 2. The method for obtaining the target reference graphic includes: translating each side of the target graphic inward, and the graphic formed by the intersection of the translated sides is the target reference graphic, wherein the distance of the inward translation of each side is greater than the maximum inward correction value.

[0014] Optionally, each edge is translated inward by the same distance.

[0015] Optionally, the distance each edge is translated inward is not equal.

[0016] Optionally, the target graphic is a rectangle, and the ratio between the length of the short side of the target graphic and the maximum inward correction value is not greater than 2. The method for obtaining the target reference graphic includes: forming a first parallel line and a second parallel line based on the axis of symmetry of the short side of the target graphic, wherein both the first parallel line and the second parallel line are parallel to the axis of symmetry of the short side, and the axis of symmetry of the short side is located between the first parallel line and the second parallel line, wherein the graphic enclosed by the intersection of the first parallel line, the second parallel line and the short side of the target graphic is the target reference graphic.

[0017] Optionally, the target graphic is a rectangle, and the ratio between the length of the short side of the target graphic and the maximum inward correction value is not greater than 2. The method for obtaining the target reference graphic includes: forming a first parallel line and a second parallel line based on the axis of symmetry of the short side of the target graphic, wherein both the first parallel line and the second parallel line are parallel to the axis of symmetry of the short side, and the axis of symmetry of the short side is located between the first parallel line and the second parallel line; translating the short side of the target graphic inward; and the graphic formed by the intersection of the translated short side and the first parallel line and the second parallel line is the target reference graphic, wherein the distance by which the short side of the target graphic is translated inward is greater than the maximum inward correction value.

[0018] Optionally, the distance between the first parallel line and the short side axis of symmetry is no greater than 2nm, and the distance between the second parallel line and the short side axis of symmetry is no greater than 2nm.

[0019] Optionally, the OPC correction includes model-based OPC correction.

[0020] Optionally, the OPC correction includes rule-based OPC correction.

[0021] As described above, the method for distinguishing linewidth errors in OPC correction patterns according to the present invention has the following beneficial effects: a target reference pattern and an OPC correction pattern are generated for the target pattern; the OPC correction pattern generates linewidth errors after mask rule checking; by judging the intersection of the linewidth errors and the target reference pattern, false linewidth errors caused by the "jagged" edges of the OPC correction pattern can be quickly distinguished, thereby reducing the processing time for linewidth errors and shortening the design cycle of integrated circuits. Attached Figure Description

[0022] Figure 1 This is a diagram illustrating a false error message generated during OPC correction.

[0023] Figure 2 The flowchart shown is a method for distinguishing OPC correction graphic line width errors in an embodiment of the present invention.

[0024] Figure 3 The diagram shown is a schematic representation of the first type of target graphic in an embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram illustrating the formation of a target comparison graphic based on a first target graphic in an embodiment of the present invention.

[0026] Figure 5 The diagram shows an OPC-corrected pattern obtained by optical proximity effect correction of a first target pattern in an embodiment of the present invention.

[0027] Figure 6This diagram illustrates how the type of linewidth error is determined based on the location of the linewidth error in the target comparison graphic and the OPC correction graphic, as shown in an embodiment of the present invention.

[0028] Figure 7 The diagram shown is a schematic representation of the second type of target graphic in an embodiment of the present invention.

[0029] Figure 8 This is a schematic diagram of the first type of target comparison graphic formed according to the second type of target graphic in an embodiment of the present invention.

[0030] Figure 9 This is a second schematic diagram illustrating the formation of a target comparison graphic based on a second target graphic in an embodiment of the present invention.

[0031] Figure 10 The diagram shown is a schematic representation of the third type of target graphic in an embodiment of the present invention.

[0032] Figure 11 This is a schematic diagram illustrating the formation of a target comparison graphic based on a third target graphic in an embodiment of the present invention.

[0033] Component labeling explanation: 1-Target graphic, 10-First rectangle, 11-Second rectangle, 2-Target reference graphic, 200-Axis of symmetry, 201-First parallel line, 202-Second parallel line, 21-First reference graphic, 22-Second reference graphic, 3-OPC correction graphic, 30-True error, 31-False error. Detailed Implementation

[0034] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0035] Please see Figures 2 to 11 It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0036] This invention provides a method for distinguishing OPC correction graphic line width errors. Please refer to [link / reference]. Figure 2 The flowchart shown is a method for distinguishing OPC correction graphic line width errors in an embodiment of the present invention, including the following steps:

[0037] S1: Provide the target graphic and obtain the maximum inward correction value when the target graphic is modified by OPC.

[0038] S2: Based on the inward correction maximum value, a target reference image of the target image is obtained, wherein the target reference image is smaller than the target image.

[0039] S3: Perform OPC correction on the target graphic to obtain an OPC-corrected graphic.

[0040] S4: According to the mask rules, obtain the line width error of the OPC correction graphic.

[0041] S5: Determine the type of line width error. If the position of the line width error intersects with the target reference graphic, it is determined to be a real error. If the position of the line width error does not intersect with the target reference graphic, it is determined to be a false error.

[0042] The method for distinguishing OPC correction graphic line width errors in this embodiment will be described in detail below with reference to the specific accompanying drawings.

[0043] First, please refer to Figure 3 Step S1: Provide target graphic 1 and obtain the maximum inward correction value when the target graphic is modified by OPC.

[0044] As an example, the target shape 1 is a single rectangle, and the maximum inward correction value is the maximum distance that can be achieved by compensating the target shape 1 inward when correcting it.

[0045] As an example, the maximum inward correction value can be obtained based on historical OPC correction data, correction experience, or by performing OPC correction on the target graphic 1.

[0046] As an example, in this embodiment, the ratio between the short side length of the target graphic 1 and the maximum inward correction value is greater than 2.

[0047] Next, please refer to Figure 4 Step S2: Based on the inward correction maximum value, obtain the target reference image 2 of the target image 1, wherein the target reference image 2 is smaller than the target image 1.

[0048] As an example, the method for obtaining the target comparison graphic 2 includes: translating each side of the target graphic 1 inward, and the graphic formed by the intersection of the translated sides is the target comparison graphic 2, wherein the distance of the inward translation of each side is greater than the maximum inward correction value.

[0049] As an example, each edge is translated inward by an equal distance. In other examples, the distances translated inward by each edge can also be set to be unequal.

[0050] As an example, the target reference graphic 2 is smaller than the target graphic 1. The target reference graphic 2 is obtained from the target graphic 1 based on the maximum value of the inward correction, ensuring that when determining the line width error type in the subsequent process, the line width error of the "jagged" edge of the OPC correction graphic will not intersect with the target reference graphic 2.

[0051] Then, please see Figure 5 Step S3: Perform OPC correction on the target graphic 1 to obtain OPC-corrected graphic 3.

[0052] As an example, when performing OPC correction on the target graphic 1, either model-based OPC (MBOPC) or rule-based OPC (RBOPC) can be performed, depending on the requirements.

[0053] As an example, in this embodiment, model-based OPC correction is performed on the target graphic 1. During OPC correction, the Edge Placement Error (EPE) is used to describe the difference between the contour obtained after OPC simulation and the target graphic 1, and can be used to evaluate the effectiveness of OPC correction. The principle of OPC correction is to first cut the target graphic 1 into different segments according to specific rules, and then continuously iterate and correct it based on the feedback results of EPE to obtain the OPC-corrected graphic 3 with "serrated" shape.

[0054] Then, step S4 is executed: according to the mask rules, the line width error of the OPC correction graphic 3 is obtained.

[0055] As an example, the linewidth error is an error caused by the OPC correction graphic 3 not conforming to the minimum linewidth limit of the mask rule.

[0056] As an example, in this embodiment, the maximum inward correction value of target graphic 1 and target reference graphic 2 are obtained first, and then OPC correction graphic 3 and line width error reporting of OPC correction graphic are obtained. In another example, OPC correction graphic 3 and line width error reporting of OPC correction graphic can be obtained first, and then the maximum inward correction value of target graphic 1 and target reference graphic 2 can be obtained. Alternatively, OPC correction graphic 3 and line width error reporting of OPC correction graphic can be performed simultaneously with obtaining the maximum inward correction value of target graphic 1 and target reference graphic 2. That is, the positions of steps S1, S2 and steps S3, S4 are adjusted during the process of distinguishing OPC correction graphic line width error reporting, and selected according to the requirements.

[0057] Then, please see Figure 6Step S5: Determine the type of line width error. If the position of the line width error intersects with the target reference graphic 2, it is determined to be a real error 30. If the position of the line width error does not intersect with the target reference graphic 2, it is determined to be a false error 31.

[0058] As an example, a linewidth error that crosses the OPC correction pattern 3 intersects with the target reference pattern 2 and is judged as a real error 30; a linewidth error with the "jagged" edge of the OPC correction pattern 3 does not intersect with the target reference pattern 2 and is judged as a false error 31. By using the logical judgment of whether the linewidth error position intersects with the target reference pattern 2, the linewidth error type of the OPC correction pattern can be quickly distinguished, and false linewidth errors caused by the "jagged" edge of the OPC correction pattern can be filtered out. That is, in the linewidth error processing, only the real error 30 is identified and output, and only the real error 30 is processed, so as to reduce the processing time of linewidth errors and shorten the integrated circuit design time.

[0059] For example, please refer to Figure 7 and Figure 8 In another example, the target shape 1 is a single rectangle, and the ratio between the length of the short side of the target shape 1 and the maximum value of the inward correction is less than or equal to 2. The method for obtaining the target reference shape 2 includes: forming a first parallel line 201 and a second parallel line 202 based on the short side symmetry axis 200 of the target shape 1. The first parallel line 201 and the second parallel line 202 are both parallel to the short side symmetry axis 200, and the short side symmetry axis 200 is located between the first parallel line 201 and the second parallel line 202. The shape enclosed by the intersection of the first parallel line 201, the second parallel line 202 and the short side of the target shape 1 is the target reference shape 2.

[0060] For example, please refer to Figure 7 and Figure 9 In another example, the target shape 1 is a single rectangle, and the ratio between the length of the short side of the target shape 1 and the maximum inward correction value is less than or equal to 2. The method for obtaining the target reference shape 2 includes: forming a first parallel line 201 and a second parallel line 202 based on the short side symmetry axis 200 of the target shape 1, where both the first parallel line 201 and the second parallel line 202 are parallel to the short side symmetry axis 200, and the short side symmetry axis 200 is located between the first parallel line 201 and the second parallel line 202; translating the short side of the target shape 1 inward; and the shape formed by the intersection of the translated short side and the first parallel line 201 and the second parallel line 202 is the target reference shape 2, wherein the distance by which the short side of the target shape 1 is translated inward is greater than the maximum inward correction value.

[0061] As an example, the short side symmetry axis 200 is the straight line containing the perpendicular bisector of the short side of the target figure 1.

[0062] As an example, the distance between the first parallel line 201 and the short side symmetry axis 200 is no greater than 2nm, and the distance between the second parallel line 202 and the short side symmetry axis 200 is no greater than 2nm.

[0063] For example, please refer to Figure 10 and Figure 11 In another example, the target shape 1 includes multiple rectangles. For example, the target shape 1 includes a first rectangle 10 and a second rectangle 11, where the ratio between the short side length of the first rectangle 10 and the maximum inward correction value is greater than 2. Figure 4 The method shown obtains the first reference pattern 21 of the first rectangle 10; the ratio between the short side length of the second rectangle 11 and the maximum inward correction value is less than or equal to 2, according to Figure 8 or Figure 9 The method shown obtains the second reference pattern 22 of the second rectangle 11, and extends and splices the first reference pattern 21 and the second reference pattern 22 to form the target reference pattern 2.

[0064] In summary, this invention provides a method for distinguishing linewidth errors caused by OPC correction patterns. It generates a target reference pattern and an OPC correction pattern for the target pattern. The OPC correction pattern generates linewidth errors after mask rule checks. By judging the intersection of the linewidth errors with the target reference pattern, it quickly distinguishes false linewidth errors caused by the "jagged" edges of the OPC correction pattern, saving processing time and shortening the integrated circuit design cycle. Therefore, this invention effectively overcomes the various shortcomings of existing technologies and has high industrial application value.

[0065] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for distinguishing OPC correction pattern line width error reporting, characterized in that, The method comprises the following steps: providing a target pattern, obtaining an inward correction maximum value when the target pattern is subjected to OPC correction; based on the inward correction maximum value, obtaining a target comparison pattern of the target pattern, the target comparison pattern being smaller than the target pattern; subjecting the target pattern to OPC correction to obtain an OPC corrected pattern; obtaining a line width error of the OPC corrected pattern according to a mask rule; judging the type of the line width error, if the position of the line width error intersects with the target comparison pattern, it is judged as a real error, if the position of the line width error does not intersect with the target comparison pattern, it is judged as a false error.

2. The method of claim 1, wherein: The line width error comprises a part of the OPC corrected pattern that does not conform to the minimum line width limit in the mask rule.

3. The method of claim 1, wherein: The target pattern is a rectangle, the ratio between the length of the short side of the target pattern and the inward correction maximum value is greater than 2, the method for obtaining the target comparison pattern comprises: translating each side of the target pattern inwardly, the pattern enclosed by the intersected sides after translation is the target comparison pattern, wherein the distance of each side translated inwardly is greater than the inward correction maximum value.

4. The method of claim 3, wherein the method further comprises: The distance of each side translated inwardly is equal.

5. The method of claim 3, wherein the method further comprises: The distance of each side translated inwardly is not equal.

6. The method of claim 1, wherein: The target pattern is a rectangle, the ratio between the length of the short side of the target pattern and the inward correction maximum value is not greater than 2, the method for obtaining the target comparison pattern comprises: forming a first parallel line and a second parallel line according to the short side symmetry axis of the target pattern, the first parallel line and the second parallel line are both parallel to the short side symmetry axis, and the short side symmetry axis is located between the first parallel line and the second parallel line, wherein the pattern enclosed by the intersection of the first parallel line, the second parallel line and the short side of the target pattern is the target comparison pattern.

7. The method of claim 1, wherein the method further comprises: determining whether the OPC correction pattern is a line pattern or a space pattern; and determining whether the line pattern is a wide line pattern or a narrow line pattern. The target pattern is a rectangle, the ratio between the length of the short side of the target pattern and the inward correction maximum value is not greater than 2, the method for obtaining the target comparison pattern comprises: forming a first parallel line and a second parallel line according to the short side symmetry axis of the target pattern, the first parallel line and the second parallel line are both parallel to the short side symmetry axis, and the short side symmetry axis is located between the first parallel line and the second parallel line, the short side of the target pattern is translated inwardly, the pattern enclosed by the intersection of the translated short side and the first parallel line and the second parallel line is the target comparison pattern, wherein the distance of the short side of the target pattern translated inwardly is greater than the inward correction maximum value.

8. The method of distinguishing OPC correction pattern line width error report according to any one of claims 6-7, wherein: The distance between the first parallel line and the short side symmetry axis is not greater than 2nm, and the distance between the second parallel line and the short side symmetry axis is not greater than 2nm.

9. The method of claim 1, wherein: The OPC correction comprises model-based OPC correction.

10. The method of claim 1, wherein: The OPC correction comprises rule-based OPC correction.

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