Method for matching AEI after photolithographic process is changed

Abstract

The invention provides a method for matching AEI after a photolithographic process is changed. The method comprises the following steps: acquiring ADI and AEI before the photolithographic process is changed and ADI and AEI after the photolithographic process is changed; matching the ADI and the AEI before and after the photolithographic process is changed to obtain an ADI difference value after the photolithographic process is changed; and adopting an interpolation method to obtain an SSA table related to the relationship between the ADI difference value and the original line width as well as the original spacing. According to the method, the SSA table about the relationship between the ADI difference value caused by the photolithography process change and the original line width and the original spacing is obtained by obtaining the ADI and the AEI before and after the photolithography change, and the ADI difference value corresponding to any original line width and the original spacing can be obtained according to the SSA table, so that the ADI matched with the AEI after the photolithography process change is obtained, and an OPC model does not need to be reconstructed, and therefore, the accuracy of the photolithography process change is improved. The correction process is simplified, and the correction time consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor integrated circuits, and in particular to a method for matching AEI after a photolithography process is changed. Background Art

[0002] When the photolithography process changes, such as replacing the photolithography machine or photoresist, the same pattern on the wafer will have a completely different outline. If the ADI Target (target value after exposure) remains unchanged, it is usually necessary to go through the OPC (Optical Proximity Correction) correction process again to match the ADI Target. This process generally takes 2 months. Summary of the invention

[0003] The object of the present invention is to provide a method for matching AEI after a photolithography process is changed, thereby simplifying the correction process and reducing the time consumption.

[0004] In order to solve the above technical problems, the present invention provides a method for matching AEI after a photolithography process is changed, comprising the following steps:

[0005] Obtain the ADI and AEI before and after the lithography process is changed;

[0006] Matching the ADI and AEI before and after the photolithography process change to obtain the ADI difference after the photolithography process change; and

[0007] The interpolation method is used to obtain the SSA table of the relationship between the ADI difference and the original line width and the original spacing.

[0008] Optionally, the method for obtaining the ADI and AEI before the lithography process is changed includes:

[0009] Determine the product masks used on the production line before the lithography process is changed;

[0010] Selecting a plurality of test patterns on the product mask, wherein the test patterns include a plurality of strips;

[0011] defining a measurement position of the test pattern and creating a measurement file including the measurement position; and

[0012] The product mask and the lithography process conditions before the lithography process change are used for exposure, development and etching, and the ADI and AEI before the lithography process change are obtained according to the measurement file.

[0013] Optionally, the method for obtaining ADI and AEI after the photolithography process is changed includes:

[0014] Design and manufacture a test mask including multiple groups of patterns, each group of patterns including multiple standard patterns, each standard pattern including multiple strips with the same line width and the same pitch, the line width of the standard patterns in each group of patterns is the same, the pitch changes sequentially, and the line width of the standard patterns in different groups of patterns is different;

[0015] Importing the test mask pattern into the existing OPC model before the photolithography process is changed, performing simulated exposure on the test mask pattern to obtain the line width after exposure, and obtaining a curve graph of the pitch and the line width after exposure;

[0016] Select a standard pattern whose line width after exposure is within the design specification as the test pattern;

[0017] defining a measurement position of the test pattern and creating a measurement file including the measurement position; and

[0018] Exposure, development and etching are performed using the test mask and the lithography process conditions after the lithography process is changed. The ADI and AEI after the lithography process is changed are obtained according to the measurement file.

[0019] Optionally, the method of matching the ADI and AEI before and after the photolithography process is changed to obtain the ADI difference after the photolithography process is changed includes:

[0020] The AEI deviation is obtained according to the AEI before the photolithography process is changed and the AEI after the photolithography process is changed;

[0021] According to the AEI deviation and the ADI after the photolithography process is changed, the ADI target value after the photolithography process is changed is obtained;

[0022] The ADI difference after the lithography process is changed is obtained according to the ADI target value after the lithography process is changed.

[0023] Optionally, the method of obtaining the AEI deviation according to the AEI before the photolithography process is changed and the AEI after the photolithography process is changed includes: obtaining the AEI deviation by subtracting the AEI after the photolithography process is changed from the AEI before the photolithography process is changed;

[0024] The method for obtaining the ADI target value after the photolithography process is changed according to the AEI deviation and the ADI after the photolithography process is changed includes: adding the AEI deviation to the ADI after the photolithography process is changed to obtain the ADI target value after the photolithography process is changed;

[0025] The method for obtaining the ADI difference after the lithography process is changed according to the ADI target value after the lithography process is changed includes: subtracting the original line width and the original deviation from the ADI target value after the lithography process is changed to obtain the ADI difference after the lithography process is changed; wherein the original deviation refers to the size expansion or reduction made to all graphics at the same time in the OPC pre-processing stage.

[0026] Optionally, a method of obtaining an SSA table of the relationship between the ADI difference and the original line width and the original spacing by interpolation includes:

[0027] The original line width, original spacing and ADI difference are formed into a table;

[0028] The ADI difference of the reference point in the table is reset to zero, and all ADI differences are rounded and divided by 2 or all ADI differences are divided by 2 and rounded to obtain a single-sided ADI difference, wherein the reference point refers to the point with the smallest line width in the photolithography process;

[0029] The SSA table is obtained by using the difference method based on the existing data in the table.

[0030] Optionally, after obtaining the SSA table, the method further includes: obtaining the ADI line width and the ADI spacing according to the single-sided ADI difference in the SSA table, and taking the ADI line width and the ADI spacing of the reference point as reference values ​​to ensure that there are no lithography process hotspots in the remaining ADI line widths and ADI spacings.

[0031] Optionally, the method of taking the ADI line width and ADI spacing of the reference point as reference values ​​and ensuring that there are no lithography process hotspots in the remaining ADI line widths and ADI spacings includes: modifying the ADI line width and ADI spacing that are smaller than the reference value to be equal to the reference value.

[0032] Optionally, the method of obtaining the ADI line width and ADI spacing according to the single-sided ADI difference in the SSA table includes: ADI spacing = original spacing - single-sided ADI difference * 2 - original deviation; ADI line width = original line width + single-sided ADI difference * 2 + original deviation; wherein the original deviation refers to the size of the expansion or reduction made to all graphics at the same time in the OPC pre-processing stage.

[0033] Optionally, after obtaining the SSA table, the method further includes: importing the SSA table when performing OPC correction to compensate for deviations introduced after the photolithography process is changed.

[0034] In summary, in the method for matching AEI after a lithography process change provided by the present invention, firstly, the ADI and AEI before the lithography process change and the ADI and AEI after the lithography process change are obtained, and then the ADI and AEI before and after the lithography process change are matched to obtain the ADI difference after the lithography process change, and then the interpolation method is used to obtain the SSA table about the relationship between the ADI difference and the original line width and the original spacing. The present invention obtains the SSA table about the relationship between the ADI difference caused by the lithography process change and the original line width and the original spacing by obtaining the ADI and AEI before and after the lithography change. According to the SSA table, the ADI difference corresponding to any original line width and the original spacing can be obtained, thereby obtaining the ADI after the lithography process change that matches the AEI, and there is no need to rebuild the OPC model, which simplifies the correction process and reduces the time consumption of correction. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flow chart of a method for matching AEI after a photolithography process change provided by an embodiment of the present invention.

[0036] Figure 2 It is a curve chart of line width and original pitch obtained by simulating exposure of the test mask pattern using the existing OPC model before the lithography process was changed. DETAILED DESCRIPTION

[0037] In the actual work of semiconductor factories, when the process conditions of lithography change, such as when replacing photoresist or lithography machine, it is necessary to ensure that the ADI (line width after development) and AEI (line width after etching) of the changed Through Pitch (including multiple strips with different line widths and pitches) are consistent with the process before the change, otherwise it means process failure. For example, when the lithography machine is changed from ASML to NIKON, although the light source type of the two brands is Annular light source (annular lighting system), and the Anchor point (reference point, the smallest point allowed for line width in the lithography process) is the same, there are still qualitative differences in the lithography process. Specifically, the same kind of graphics in the same mask have a large difference in the ADI profile (ADIProfile) after exposure in the two lithography machines, and this difference will further affect the deviation of ADI and AEI. Therefore, when the lithography process changes, it is necessary to go through the OPC correction process again to match the ADI Target (ADI target), but this operation takes a long time.

[0038] In view of the above problems, the present invention takes saving OPC correction time as a starting point, and simplifies the OPC correction process when the photolithography process is changed, so as to reduce the time consumption.

[0039] In order to make the purpose, advantages and features of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.

[0040] As used in the present invention, the singular forms "one", "an", and "the" include plural objects, unless the content clearly indicates otherwise. As used in the present invention, the term "or" is generally used in a sense that includes "and / or", unless the content clearly indicates otherwise. As used in the present invention, the term "several" is generally used in a sense that includes "at least one", unless the content clearly indicates otherwise. As used in the present invention, the term "at least two" is generally used in a sense that includes "two or more", unless the content clearly indicates otherwise. In addition, the terms "first", "second", and "third" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first", "second", and "third" may explicitly or implicitly include one or at least two of the features.

[0041] Figure 1 This is a flow chart of a method for matching AEI after a photolithography process change provided by an embodiment of the present invention. Figure 1 As shown, the method for matching AEI after the photolithography process is changed provided by the embodiment of the present invention includes the following steps:

[0042] S1: Obtain the ADI and AEI before the lithography process is changed and the ADI and AEI after the lithography process is changed;

[0043] S2: Matching the ADI and AEI before and after the photolithography process change to obtain the ADI difference after the photolithography process change;

[0044] S3: Use interpolation method to obtain the SSA table of the relationship between the ADI difference and the original line width and the original spacing.

[0045] In this embodiment, the change of the lithography machine is taken as an example for explanation. For example, before the change, it is an ASML lithography machine, and after the change, it is a NIKON lithography machine. That is, the ASML lithography machine represents the process before the change, and the NIKON lithography machine represents the process after the change.

[0046] In step S1 , the ADI and AEI before the photolithography process is changed and the ADI and AEI after the photolithography process is changed are obtained.

[0047] In this embodiment, a method for obtaining ADI and AEI before the photolithography process is changed is first introduced.

[0048] First, determine the product mask used on the production line before the photolithography process change, that is, select a product mask used on the production line. Because it is a product mask, its pattern characteristics are disordered and irregular.

[0049] Next, multiple test patterns are selected on the product mask, and the test patterns include multiple strips. Exemplarily, the number of the selected test patterns is greater than or equal to 50. In addition, the selected multiple test patterns need to cover isolated patterns (ISO) and dense patterns (Dense) of different line widths, so as to facilitate interpolation when the SSA table is subsequently prepared.

[0050] Then, define the measurement position of the test pattern and create a measurement (Gauge) file containing the measurement position. In this embodiment, the measurement position can be a strip in the middle of the test pattern, that is, measure the line width (CD) of the strip, but of course it is not limited to the strip.

[0051] Afterwards, the product mask and the lithography process conditions before the lithography process change are used for exposure, development and etching, and the ADI and AEI before the lithography process change are measured according to the measurement file. In this embodiment, the product mask and the ASML lithography machine are first used for exposure, and the measurement recipe of ADI is established with the help of CDSEM (scanning electron microscope for feature size measurement) according to the measurement file to obtain the ADI before the process change, that is, ADI_ASML. Then, the etching machine used in the production line is used for etching, and the measurement recipe of AEI is established with the help of CDSEM according to the measurement file to obtain the AEI before the process change, that is, AEI_ASML.

[0052] Table 1

[0053] serial number Gauge_name Drawn Pitch ADI_ASML AEI_ASML 1 mbar_144p693 144 693 181.094 187.654 2 mbar_144p225 144 225 152.376 144.174 3 mbar_144p531 144 531 181.98 188.078 4 mbar_90p495 90 495 132.572 138.124 5 mbar_378p868 378 868 419.825 426.671 6 mbar_144p603 144 603 182.065 188.129 7 mbar_90p180 90 180 107.601 100.17 8 mbar_162p2000 162 2000 201.02 206.241 9 mbar_315p1170 315 1170 350.381 356.439 10 mbar_648p849 648 849 625.155 626.457 11 mbar_450p900 450 900 519.368 526.024 12 mbar_144p261 144 261 162.197 157.434 13 mbar_81p162 81 162 96.877 88.693 14 mbar_63p1100 63 1100 105.483 110.47 15 mbar_63p198 63 198 96.893 93.47 16 mbar_135p2000 135 2000 180.457 185.474 17 mbar_324p495 324 495 329.179 329.611 18 mbar_63p126 63 126 68.065 60.768 19 mbar_765p972 765 972 618.447 625.126 20 mbar_63p162 63 162 86.753 80.029 21 mbar_153p648 153 648 202.261 208.722 22 mbar_63p189 63 189 98.751 93.684 23 mbar_108p180 108 180 114.331 106.053 24 mbar_144p495 144 495 182.949 188.414 25 mbar_450p783 450 783 521.559 526.864 26 mbar_576p929 576 929 620.497 625.876

[0054] Table 1 is an example of ADI and AEI before the photolithography process change measured in one embodiment. Gauge_name is the measurement name in the measurement file, which records the original line width and original pitch of the measured pattern. For example, mbar_144p693 measures a test pattern with an original line width (Drawn) of 144 and an original pitch (Pitch) of 693. The CD measured after the pattern is exposed and developed is ADI_ASML, and the CD measured after etching is AEI_ASML. The original line width, original pitch, and the original spacing mentioned later are the initial sizes of the pattern in the GDS layout.

[0055] Next, the method of obtaining ADI and AEI after the lithography process is changed is introduced.

[0056] First, a test mask including multiple groups of graphics is designed and produced, each group of graphics includes multiple standard graphics, each standard graphic includes multiple strips with the same line width and the same pitch, the line width of the standard graphics in each group of graphics is the same, the pitch changes sequentially, and the line width of the standard graphics in different groups of graphics is different. That is, the line width of each standard graphic is the same and the pitch is the same, all the standard graphics in each group have the same line width, the pitch changes sequentially (for example, increases sequentially), and the line width of the standard graphics in different groups is different. That is, the line width of the standard graphics in each group is the same, and the line width of the standard graphics in one group is different from that of the standard graphics in another group. Because it is a test mask, its graphic characteristics are orderly and regular.

[0057] Then, the test mask pattern is imported into the existing OPC model before the photolithography process is changed, the test mask pattern is simulated exposed to obtain the line width after exposure, and a curve graph of the original spacing and the line width after exposure is obtained.

[0058] Figure 2 This is a curve chart of line width and original pitch obtained by simulating exposure of the test mask pattern using the existing OPC model before the lithography process change. Please refer to Figure 2 As shown, the horizontal axis is the original pitch, and the vertical axis is the line width (CD) after simulated exposure.

[0059] Next, a standard pattern with a line width within the design specification after exposure is selected as a test pattern. That is, patterns with a size smaller than the design specification (Subrule) and a size larger than the maximum design specification (Overrule) are removed. In this embodiment, for example, data smaller than 70nm and data larger than 400nm are removed, that is, data between 70nm and 400nm are selected, such as Figure 2 As shown in the dotted box in the figure, select the standard figure corresponding to the value in the dotted box as the test figure.

[0060] Then, define the measurement position of the test pattern and create a measurement (Gauge) file containing the measurement position. In this embodiment, the measurement position can be the long strip in the middle of the test pattern, that is, measure the line width (CD) of the long strip, but of course it is not limited to the long strip.

[0061] Afterwards, the test mask and the lithography process conditions after the lithography process is changed are used for exposure, development and etching, and the ADI and AEI after the lithography process is changed are measured according to the measurement file. In this embodiment, the test mask and the NIKON lithography machine are first used for exposure, and the measurement recipe of ADI is established with the help of CDSEM (scanning electron microscope for feature size measurement) according to the measurement file to obtain the ADI after the process change, that is, ADI_NIKON. Then, the etching machine used in the production line is used for etching, and the measurement recipe of AEI is established with the help of CDSEM according to the measurement file to obtain the AEI after the process change, that is, AEI_NIKON.

[0062] Table 2

[0063]

[0064]

[0065] Table 2 is an example of ADI and AEI measured after the photolithography process is changed in one embodiment. Gauge_name is the measurement name in the measurement file, which records the original line width and original pitch of the measured pattern. For example, the mbar_68p120 measurement is a test pattern with an original line width of 68 and an original pitch of 120. After the pattern is exposed and developed, the CD measured is ADI_NIKON, and after etching, the CD measured is AEI_NIKON.

[0066] In step S2, the ADI and AEI before and after the photolithography process is changed are matched to obtain the ADI difference after the photolithography process is changed.

[0067] In the previous step, the ADI and AEI before the lithography process change are obtained as ADI_ASML and AEI_ASML, and the ADI and AEI after the lithography process change are obtained as ADI_NIKON and AEI_NIKON. Then, the AEI deviation is obtained according to the AEI before the lithography process change and the AEI after the lithography process change. Specifically, the AEI deviation is obtained by subtracting the AEI after the lithography process change from the AEI before the lithography process change, that is, AEI_Bias=AEI_ASML-AEI_NIKON. Then, the ADI target value after the lithography process change is obtained according to the AEI deviation and the ADI after the lithography process change. For example, the AEI deviation is added to the ADI after the lithography process change to obtain the ADI target value after the lithography process change, that is, ADI_TGT=AEI_Bias+ADI_NIKON. Afterwards, the ADI difference after the change of the lithography process is obtained according to the ADI target value after the change of the lithography process. For example, the ADI difference after the change of the lithography process is obtained by subtracting the original line width and the original deviation from the ADI target value after the change of the lithography process, that is, Bias = ADI_TGT-Drawn-Global_Bias, where the original deviation (Global_Bias) refers to the enlargement or reduction of the size of all graphics at the same time in the OPC pre-processing stage.

[0068] Table 3

[0069]

[0070]

[0071] Table 3 is a table example of the relationship between the ADI difference and the original line width and original spacing in one embodiment. Among them, Gauge_name is the measurement name in the measurement file, mbar_144p693 measures a test pattern with an original line width of 144 and an original pitch of 693, Drawn is the original line width of the measurement pattern, Space is the original spacing of the measurement pattern, Pitch is the original pitch of the measurement pattern, where Pitch = Drawn + Space, ADI_ASML and AEI_ASML are ADI and AEI before the lithography process is changed, and ADI_NIKON and AEI_NIKON are ADI and AEI after the lithography process is changed. According to AEI_ASML and AEI_NIKON, the AEI deviation (AEI_Bias) can be obtained, and the ADI target (ADI_TGT) can be obtained according to the AEI deviation (AEI_Bias) and ADI_NIKON. Then, the ADI difference (Bias) after the lithography process change is obtained according to the AEI deviation (AEI_Bias), the original line width (Drawn) and the original deviation, thereby obtaining the relationship between the ADI difference after the lithography process change and the original line width and the original spacing.

[0072] In this step, the ADI and AEI before and after the photolithography process is changed are matched to obtain the ADI difference after the process is changed.

[0073] In step S3, an interpolation method is used to obtain an SSA table of the relationship between the ADI difference and the original line width and the original spacing.

[0074] Exemplarily, first, the original line width, the original spacing, and the ADI difference are combined into a table. Specifically, the original line width (Drawn), the original spacing (space), and the ADI difference (Bias) in the above Table 3 are combined into a table.

[0075] Table 4

[0076]

[0077]

[0078] Table 4 is an example of a table consisting of the original line width, original spacing, and ADI difference. The first row of the table is the original line width Drawn, the first column is the original spacing Space, and the value in the middle is the ADI difference Bias corresponding to the specific original line width and original spacing. The ADI difference Bias with a value is the real data obtained through measurement and calculation, and the blank is no data, which needs to be obtained through interpolation later.

[0079] Next, the ADI difference of the reference point in the table is reset to zero, and all ADI differences are rounded and divided by 2 or all ADI differences are divided by 2 and rounded to obtain a single-sided ADI difference (still defined as Bias in subsequent tables). The reference point refers to the point with the smallest line width in the photolithography process. For example, in this embodiment, the original line width of the reference point is 68nm and the original pitch is 126nm.

[0080] Then, a complete table, namely, an SSA table, is obtained by using the difference method according to the existing data in the table. In this embodiment, after the complete table is obtained by using the interpolation method, the unreasonable values ​​therein can be fine-tuned (Smoothed) according to the changes in the values.

[0081] Table 5

[0082]

[0083]

[0084] Table 5 is an SSA table. The gray values ​​in the original line width Drawn and the original spacing Space are interpolated to reduce the change of the original line width or the original spacing. The blue values ​​in the single-sided ADI difference Bias are real data obtained through measurement and calculation. The remaining values ​​are differences generated by interpolation.

[0085] The above SSA table can be used to look up NIKON's ADI difference bias.

[0086] In one embodiment of the present invention, after obtaining the SSA table, it also includes: obtaining the ADI line width and ADI spacing according to the single-sided ADI difference in the SSA table, and using the ADI line width and ADI spacing of the reference point as reference values ​​to ensure that there are no lithography process hotspots in the remaining ADI line widths and ADI spacings.

[0087] Exemplarily, the method of obtaining the ADI line width and ADI spacing according to the single-sided ADI difference in the SSA table includes: ADI spacing = original spacing - single-sided ADI difference * 2 - original bias, that is, ADI_Space = Space-Bias*2-Globals_bias; ADI line width = original line width + single-sided ADI difference * 2 + original bias, that is, ADI_CD = Drawn + Bias*2 + Globals_bias; wherein the original bias refers to the size of the expansion or reduction made to all graphics at the same time in the OPC pre-processing stage.

[0088] Table 6

[0089]

[0090]

[0091] Table 6 shows the relationship between the ADI line width ADI_CD, the original line width Drawn, and the original spacing Space. The ADI line width is obtained by ADI_CD=Drawn+Bias*2+Globals_bias.

[0092] Table 7

[0093]

[0094]

[0095] Table 7 is an example of the relationship between the ADI spacing ADI_Space and the original line width Drawn and the original spacing Space. The corresponding relationship between the ADI spacing and the original line width and the original spacing is obtained through the formula ADI_Space=Space-Bias*2-Globals_bias.

[0096] In this embodiment, after obtaining the ADI line width and ADI spacing, the ADI line width and ADI spacing of the reference point are used as reference values ​​to ensure that there are no photolithography process hotspots in the remaining ADI line widths and ADI spacings. Exemplarily, the ADI line width and ADI spacing that are smaller than the reference value are modified to be equal to the reference value to avoid photolithography process hotspots with potential risks such as broken lines, pinches, or bridges after the deviation is compensated.

[0097] After the SSA table is obtained, the method further includes: importing the SSA table during OPC correction to compensate for the deviation introduced after the photolithography process is changed.

[0098] In summary, in the method for matching AEI after a lithography process change provided by the present invention, firstly, the ADI and AEI before the lithography process change and the ADI and AEI after the lithography process change are obtained, and then the ADI and AEI before and after the lithography process change are matched to obtain the ADI difference after the lithography process change, and then the interpolation method is used to obtain the SSA table about the relationship between the ADI difference and the original line width and the original spacing. The present invention obtains the SSA table about the relationship between the ADI difference caused by the lithography process change and the original line width and the original spacing by obtaining the ADI and AEI before and after the lithography change. According to the SSA table, the ADI difference corresponding to any original line width and the original spacing can be obtained, thereby obtaining the ADI after the lithography process change that matches the AEI, and there is no need to rebuild the OPC model, which simplifies the correction process and reduces the time consumption of correction.

[0099] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A method for matching AEI after a photolithography process change, characterized in that: The following steps are involved: Obtain the ADI and AEI before and after the lithography process is changed; Matching the ADI and AEI before and after the photolithography process change to obtain the ADI difference after the photolithography process change; as well as The interpolation method is used to obtain the SSA table of the relationship between the ADI difference and the original line width and the original spacing.

2. The method for matching AEI after photolithography process change according to claim 1, characterized in that: Methods for obtaining ADI and AEI before the lithography process is changed include: Determine the product masks used on the production line before the lithography process is changed; Selecting a plurality of graphics on the product mask, wherein the graphics include a plurality of strips; defining the measurement positions of the graphics and creating a measurement file including the measurement positions; and The product mask and the lithography process conditions before the lithography process change are used for exposure, development and etching, and the ADI and AEI before the lithography process change are obtained according to the measurement file.

3. The method for matching AEI after photolithography process change according to claim 1, characterized in that: Methods for obtaining ADI and AEI after the lithography process is changed include: Design and manufacture a test mask including multiple groups of patterns, each group of patterns including multiple standard patterns, each standard pattern including multiple strips with the same line width and the same pitch, the line width of the standard patterns in each group of patterns is the same, and the pitch changes sequentially, and the line width of the standard patterns in different groups of patterns is different; Importing the test mask pattern into the existing OPC model before the photolithography process is changed, performing simulated exposure on the test mask pattern to obtain the line width after exposure, and obtaining a curve graph of the pitch and the line width after exposure; Select a standard pattern whose line width after exposure is within the design specification as the test pattern; defining a measurement position of the test pattern and creating a measurement file including the measurement position; and Exposure, development and etching are performed using the test mask and the lithography process conditions after the lithography process is changed. The ADI and AEI after the lithography process is changed are obtained according to the measurement file.

4. The method for matching AEI after photolithography process change according to claim 1, characterized in that: The method of matching the ADI and AEI before and after the lithography process change to obtain the ADI difference after the lithography process change includes: The AEI deviation is obtained according to the AEI before the photolithography process is changed and the AEI after the photolithography process is changed; According to the AEI deviation and the ADI after the photolithography process is changed, the ADI target value after the photolithography process is changed is obtained; The ADI difference after the lithography process is changed is obtained according to the ADI target value after the lithography process is changed.

5. The method for matching AEI after photolithography process change according to claim 4, characterized in that: The method of obtaining an AEI deviation according to the AEI before the photolithography process is changed and the AEI after the photolithography process is changed includes: subtracting the AEI after the photolithography process is changed from the AEI before the photolithography process is changed to obtain the AEI deviation; The method for obtaining the ADI target value after the photolithography process is changed according to the AEI deviation and the ADI after the photolithography process is changed includes: adding the AEI deviation to the ADI after the photolithography process is changed to obtain the ADI target value after the photolithography process is changed; The method for obtaining the ADI difference after the lithography process is changed according to the ADI target value after the lithography process is changed includes: subtracting the original line width and the original deviation from the ADI target value after the lithography process is changed to obtain the ADI difference after the lithography process is changed; wherein the original deviation refers to the size expansion or reduction made to all graphics at the same time in the OPC pre-processing stage.

6. The method for matching AEI after photolithography process change according to claim 1, characterized in that: Methods for obtaining an SSA table of the relationship between the ADI difference and the original line width and the original spacing by interpolation include: The original line width, original spacing and ADI difference are formed into a table; The ADI difference of the reference point in the table is reset to zero, and all ADI differences are rounded and divided by 2 or all ADI differences are divided by 2 and rounded to obtain a single-sided ADI difference, wherein the reference point refers to the point with the smallest line width in the photolithography process; The SSA table is obtained by using the difference method based on the existing data in the table.

7. The method for matching AEI after photolithography process change according to claim 6, characterized in that: After obtaining the SSA table, the following steps are also included: obtaining the ADI line width and the ADI spacing according to the single-sided ADI difference in the SSA table, and taking the ADI line width and the ADI spacing of the reference point as reference values ​​to ensure that there are no lithography process hotspots in the remaining ADI line widths and ADI spacings.

8. The method for matching AEI after photolithography process change according to claim 7, characterized in that: The method of ensuring that there are no photolithography process hot spots in the remaining ADI line widths and ADI spacings by taking the ADI line width and ADI spacing of the reference point as reference values ​​includes: modifying the ADI line width and ADI spacing that are smaller than the reference value to be equal to the reference value.

9. The method for matching AEI after photolithography process change according to claim 7, characterized in that: The method of obtaining the ADI line width and ADI spacing according to the single-sided ADI difference in the SSA table includes: ADI spacing = original spacing - single-sided ADI difference * 2 - original deviation; ADI line width = original line width + single-sided ADI difference * 2 + original deviation; wherein the original deviation refers to the size of the expansion or reduction made to all graphics at the same time during the OPC pre-processing stage.

10. The method for matching AEI after photolithography process change according to claim 1, characterized in that: After the SSA table is obtained, the method further includes: importing the SSA table when performing OPC correction to compensate for the deviation introduced after the photolithography process is changed.

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