Optical proximity correction method

Abstract

An optical proximity correction method comprises the steps that an initial layout is provided, and the initial layout comprises a plurality of main patterns; generating a plurality of first auxiliary graphs on the periphery of the main graph, and generating an intermediate layout; obtaining graph density based on the middle layout; and according to the pattern density, performing optical proximity correction by adopting an optical proximity correction model considering the pattern density, and generating a correction layout. Due to the fact that the first auxiliary graph exists in the finally formed exposure layout, the first auxiliary graph is added before optical proximity correction, and the main graph and the first auxiliary graph are considered at the same time when the graph density is calculated. The graph density obtained through calculation tends to be consistent with the real graph density in the exposure layout, so that the more accurate graph density can be called for optical proximity correction by adopting the optical proximity correction model considering the graph density, and the precision of the optical proximity correction is improved.

Description

Technical Field

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

[0002] Integrated circuit manufacturing technology is a complex process with rapid technological updates. A key parameter characterizing integrated circuit manufacturing technology is the minimum feature size, i.e., the critical dimension (CD). As the critical dimension shrinks, even down to the nanometer level, it is precisely due to the reduction of the critical dimension that it becomes possible to arrange millions of devices on each chip.

[0003] Lithography technology is the driving force for the development of integrated circuit manufacturing processes and is also one of the most complex technologies. Compared with other individual manufacturing technologies, the improvement of lithography technology is of great significance for the development of integrated circuits. Before the lithography process begins, first, the pattern needs to be copied onto a mask plate through a specific device, and then through a lithography device, light of a specific wavelength is used to copy the pattern structure on the mask plate onto the silicon wafer for manufacturing the chip. However, due to the reduction in the size of semiconductor devices, distortion will occur during the process of transferring the pattern to the silicon wafer. If this distortion phenomenon is not eliminated, it will lead to the failure of the entire manufacturing technology. Therefore, to solve the above problem, optical proximity correction (OPC) can be performed on the mask plate. The optical proximity correction method is to perform pre-treatment on the lithography mask plate before lithography and make pre-modifications so that the amount of modification compensation can exactly compensate for the optical proximity effect caused by the exposure system.

[0004] However, there are still many problems in optical proximity correction in the prior art. Summary of the Invention

[0005] The technical problem solved by the present invention is to provide an optical proximity correction method to improve the accuracy of optical proximity correction.

[0006] To solve the above problem, the technical solution of the present invention provides an optical proximity correction method, including: providing an initial layout, where the initial layout includes several main patterns; generating several first auxiliary patterns around the main patterns to generate an intermediate layout; obtaining a pattern density based on the intermediate layout; and performing optical proximity correction using an optical proximity correction model considering the pattern density to generate a corrected layout.

[0007] Optionally, the main pattern is a device pattern for generating an actual functional device, and the main pattern is exposed and developed on a photoresist layer.

[0008] Optionally, the first auxiliary pattern is generated in a manner based on one or more of rules and models.

[0009] Optionally, the first auxiliary pattern is a redundant pattern that is not used to generate an actual functional device, and the first auxiliary pattern is exposed and developed on the photoresist layer.

[0010] Optionally, the method for obtaining the pattern density includes: establishing a scanning window for the pattern density, with the main pattern and the first auxiliary pattern covered within the scanning window; taking the ratio between the sum of the areas of all the main patterns and the first auxiliary pattern within the scanning window and the area of the scanning window as the pattern density.

[0011] Optionally, the method for performing optical proximity correction using the optical proximity correction model includes: excluding the first auxiliary pattern and performing optical proximity correction on the main pattern using the optical proximity correction model.

[0012] Optionally, the method for excluding the first auxiliary pattern and performing optical proximity correction on the main pattern using the optical proximity correction model includes: performing an exclusive OR operation on the initial layout and the intermediate layout to identify and mark the generated first auxiliary pattern; the optical proximity correction model performs optical proximity correction on the unmarked main pattern.

[0013] Optionally, the process of performing optical proximity correction using the optical proximity correction model includes: generating a number of second auxiliary patterns around the main pattern.

[0014] Optionally, the second auxiliary pattern is a sub-resolution pattern, and the second auxiliary pattern is not exposed and developed on the photoresist layer.

[0015] Optionally, after obtaining the corrected layout, it further includes: performing a mask rule check on the patterns in the corrected layout to generate an exposure layout.

[0016] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0017] In the optical proximity correction method of the technical solution of the present invention, before performing optical proximity correction, the first auxiliary pattern is added to the initial layout to generate the intermediate layout, and the pattern density is obtained based on the intermediate layout. According to the pattern density, an optical proximity correction model considering the pattern density is used for optical proximity correction to generate the corrected layout. Since the first auxiliary pattern exists in the finally formed exposure layout, the first auxiliary pattern is added before performing the optical proximity correction, and both the main pattern and the first auxiliary pattern are taken into account when calculating the pattern density, so that the calculated pattern density tends to be consistent with the true pattern density in the exposure layout. Furthermore, when using the optical proximity correction model considering the pattern density, a more accurate pattern density can be called for optical proximity correction, thereby improving the accuracy of optical proximity correction.

[0018] Furthermore, the method of performing optical proximity correction using the optical proximity correction model includes: excluding the first auxiliary pattern and performing optical proximity correction on the main pattern using the optical proximity correction model. Since the first auxiliary pattern is a redundant pattern that is not used to generate actual functional devices, even if the first auxiliary pattern is exposed and developed on the photoresist layer, the finally generated structure does not have actual device functions. Therefore, whether to correct the first auxiliary pattern does not affect the performance of the functional device. Therefore, excluding the correction of the first auxiliary pattern during the optical proximity correction process and only correcting the main pattern can reduce the computational amount involved in the correction process, thereby improving the efficiency of optical proximity correction.

[0019] Furthermore, after obtaining the corrected layout, it further includes: performing a mask rule check on the patterns in the corrected layout to generate the exposure layout. Through the mask rule check, it is ensured that the mask patterns after optical proximity correction meet the requirements of the mask manufacturing process. Check whether the corrected patterns meet the rule requirements such as the minimum feature size and pitch, to avoid difficulties in mask manufacturing caused by correction. At the same time, the results of the mask rule check can also be fed back to the optical proximity correction algorithm to optimize the correction strategy, balance the lithography imaging quality and mask manufacturing feasibility, thereby ensuring the smooth progress of the semiconductor manufacturing process. Description of the Drawings

[0020] Figure 1 is the flowchart of the optical proximity correction method according to an embodiment of the present invention;

[0021] Figures 2 to 5 is the schematic structural diagram of each step of the optical proximity correction method in an embodiment of the present invention;

[0022] Figure 6In the process of establishing an optical proximity correction model considering pattern density in an embodiment of the present invention, the OPC test pattern provided is a structure schematic diagram in which a test auxiliary pattern is set near the test main pattern to consider the influence of the one-dimensional pattern density near the test pattern on its critical dimension;

[0023] Figure 7 In the process of establishing an optical proximity correction model considering pattern density in an embodiment of the present invention, the OPC test pattern provided is a structure schematic diagram in which a set area is framed around the test main pattern to consider the influence of the two-dimensional pattern density in the area around the test pattern on its critical dimension. Detailed implementation manners

[0024] As described in the background art, there are still many problems in optical proximity correction in the prior art. Specific descriptions will be given below.

[0025] In the process of establishing the current optical proximity correction model, neither the correction model nor the menu reflects the actual influence of pattern density on pattern accuracy. Therefore, there is no requirement for pattern density when collecting data during the modeling of the existing optical proximity correction model. When the lithography process approaches the resolution limit, the influence of pattern density, especially local pattern density, cannot be ignored. Obviously, the optical proximity correction model that does not consider pattern density is bound to have problems that the critical dimension and process window of the corrected pattern cannot meet the design requirements.

[0026] To solve the above problems, in the prior art, by adding variables related to the pattern density of the test pattern during the modeling process of the optical proximity correction model, the established optical proximity correction model includes the mapping relationship between the critical dimension of the pattern and the variables related to the pattern density. Then, the critical dimension distortion of the test pattern in different pattern density environments is determined using this optical proximity correction model, and then compared with the designed critical dimension of the test pattern. Thus, the correction amount of the test pattern during the optical proximity correction process can be determined, thereby improving the accuracy during the optical proximity correction process, further improving the process window of the layout, and effectively improving the product yield.

[0027] However, the existing optical proximity correction is performed before the auxiliary pattern filling, or the auxiliary pattern is excluded through a redundant pattern exclusion layer. At this time, there will be problems in calculating the pattern density, which is not the pattern density in the true final exposure layout, but only the density of the main pattern. If the calculated pattern density is applied to the optical proximity correction model considering pattern density, it will lead to inaccurate calculation of the pattern density, resulting in incorrect pattern density being called by the optical proximity correction model and causing correction errors, thereby affecting the correction accuracy of the pattern.

[0028] On this basis, the present invention provides an optical proximity correction method. Before performing optical proximity correction, the first auxiliary pattern is added to the initial layout to generate the intermediate layout, and the pattern density is obtained based on the intermediate layout. According to the pattern density, an optical proximity correction model considering the pattern density is used to perform optical proximity correction to generate the corrected layout. Since the first auxiliary pattern exists in the finally formed exposure layout, the first auxiliary pattern is added before performing the optical proximity correction, and both the main pattern and the first auxiliary pattern are taken into account when calculating the pattern density, so that the calculated pattern density is close to the true pattern density in the exposure layout. Furthermore, when using the optical proximity correction model considering the pattern density, a more accurate pattern density can be called for optical proximity correction, thereby improving the accuracy of optical proximity correction.

[0029] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following specifically describes the embodiments of the present invention in detail with reference to the accompanying drawings.

[0030] Figure 1 It is a flowchart of the optical proximity correction method according to an embodiment of the present invention, including:

[0031] Step S101: Provide an initial layout, where the initial layout includes a plurality of main patterns;

[0032] Step S102: Generate a plurality of first auxiliary patterns outside the main patterns to generate an intermediate layout;

[0033] Step S103: Obtain the pattern density based on the intermediate layout;

[0034] Step S104: According to the pattern density, use an optical proximity correction model considering the pattern density to perform optical proximity correction to generate a corrected layout.

[0035] The following details the steps of the optical proximity correction method with reference to the accompanying drawings.

[0036] Figures 2 to 5 It is a schematic structural diagram of each step of the optical proximity correction method according to an embodiment of the present invention; Figure 6 It is a schematic structural diagram of an OPC test pattern provided during the establishment of an optical proximity correction model considering pattern density according to an embodiment of the present invention. A test auxiliary pattern is set near the test main pattern to consider the influence of the one-dimensional pattern density near the test pattern on its critical dimension; Figure 7 It is a schematic structural diagram of an OPC test pattern provided during the establishment of an optical proximity correction model considering pattern density according to an embodiment of the present invention. A set area is framed around the test main pattern to consider the influence of the two-dimensional pattern density in the surrounding area of the test pattern on its critical dimension.

[0037] Please refer to Figure 2 , and provide an initial layout, where the initial layout includes a number of main patterns 101.

[0038] In this embodiment, the main pattern 101 is a device pattern for generating an actual functional device, and the main pattern 101 is exposed and developed on a photoresist layer.

[0039] Please refer to Figure 3 , and generate a number of first auxiliary patterns 102 around the main pattern 101 to generate an intermediate layout.

[0040] In this embodiment, the first auxiliary pattern 102 is a redundant pattern that is not used to generate an actual functional device, and the first auxiliary pattern 102 is exposed and developed on a photoresist layer.

[0041] In this embodiment, by generating the first auxiliary pattern 102 around the main pattern 101, it is used to fill the empty area around the main pattern 101 to keep the pattern area consistent within a large range. The structure finally formed by the first auxiliary pattern 102 and the structure forming the actual device function constitute a physically uniform distribution structure, thereby ensuring the uniformity of processing technologies such as etching and grinding in the semiconductor manufacturing process, as well as physical strength and heat dissipation uniformity.

[0042] In this embodiment, the first auxiliary pattern 102 is generated in one or more ways based on rules and based on models. Among them, the rule-based generation method quickly generates the first auxiliary pattern 102 according to preset rules, and its advantage is simplicity and high efficiency, but the flexibility is poor. The model-based generation method calculates and optimizes the position and shape of the first auxiliary pattern 102 precisely to achieve the best lithography effect, but the computational complexity is high. The first auxiliary pattern 102 can be generated by combining the two methods. The specific process is to first quickly generate an initial pattern based on rules, and then simulate and optimize the initial pattern based on the model to form the first auxiliary pattern 102, which combines efficiency and accuracy.

[0043] Please refer to Figure 4 , and obtain the pattern density based on the intermediate layout.

[0044] In this embodiment, the method for obtaining the pattern density includes: establishing a scanning window S for the pattern density, where the scanning window S covers the main pattern 101 and the first auxiliary pattern 102; taking the ratio between the sum of the areas of all the main patterns 101 and the first auxiliary patterns 102 within the scanning window S and the area of the scanning window S as the pattern density.

[0045] Please refer to Figure 5, according to the pattern density, an optical proximity correction model considering the pattern density is used for optical proximity correction to generate a corrected layout.

[0046] Before performing optical proximity correction, the first auxiliary pattern 102 is added to the initial layout to generate the intermediate layout, and the pattern density is obtained based on the intermediate layout. According to the pattern density, the optical proximity correction model considering the pattern density is used for optical proximity correction to generate a corrected layout. Since the first auxiliary pattern 102 exists in the finally formed exposure layout, the first auxiliary pattern 102 is added before performing the optical proximity correction, and both the main pattern 101 and the first auxiliary pattern 102 are taken into account when calculating the pattern density, so that the calculated pattern density is closer to the true pattern density in the exposure layout. Furthermore, when using the optical proximity correction model considering the pattern density, a more accurate pattern density can be called for optical proximity correction, thereby improving the accuracy of optical proximity correction.

[0047] In this embodiment, the method for performing optical proximity correction using the optical proximity correction model includes: excluding the first auxiliary pattern 102 and performing optical proximity correction on the main pattern 101 using the optical proximity correction model.

[0048] Since the first auxiliary pattern 102 is a redundant pattern that is not used to generate an actual functional device, even if the first auxiliary pattern 102 is exposed and developed on the photoresist layer, the finally generated structure does not have an actual device function. Therefore, whether to correct the first auxiliary pattern 102 does not affect the performance of the functional device. Therefore, during the optical proximity correction process, the correction of the first auxiliary pattern 102 is excluded, and only the main pattern 101 is corrected, which can reduce the amount of calculation involved in the correction process, thereby improving the efficiency of optical proximity correction.

[0049] In this embodiment, the method for excluding the first auxiliary pattern 102 and performing optical proximity correction on the main pattern 101 using the optical proximity correction model includes: performing an exclusive OR operation on the initial layout and the intermediate layout to identify and mark the generated first auxiliary pattern 102; the optical proximity correction model performs optical proximity correction on the unmarked main pattern 101.

[0050] Please continue to refer to Figure 5 , in this embodiment, the main pattern 101 after being corrected by the optical proximity correction model forms a corrected pattern 103.

[0051] In this embodiment, the process of performing optical proximity correction using the optical proximity correction model includes: generating a plurality of second auxiliary patterns (not shown) around the main pattern 101; the second auxiliary patterns are sub-resolution patterns, and the second auxiliary patterns are not exposed and developed on the photoresist layer. In optical proximity correction, sub-resolution assist patterns are a key correction means. Sub-resolution assist patterns are tiny patterns added around the main pattern 101, whose size is smaller than the lithography resolution and will not form an actual pattern on the photoresist. They change the diffraction and interference patterns of light, enhance the light intensity contrast of the main pattern 101, reduce the proximity effect, thereby improving the lithography imaging quality and consistency. Sub-resolution assist patterns can also be added in the form of a combination of rule-based and model-based methods to adapt to different layout structures and process requirements.

[0052] Please continue to refer to Figure 5 , in this embodiment, after obtaining the corrected layout, mask rule checking is performed on the patterns in the corrected layout to generate an exposure layout.

[0053] Through the mask rule checking to ensure that the mask patterns after optical proximity correction meet the requirements of the mask manufacturing process. Check whether the corrected patterns meet the rule requirements such as the minimum feature size and pitch, to avoid difficulties in mask manufacturing caused by correction. At the same time, the results of the mask rule checking can also be fed back to the optical proximity correction algorithm to optimize the correction strategy, balance the lithography imaging quality and mask manufacturing feasibility, thereby ensuring the smooth progress of the semiconductor manufacturing process.

[0054] It should be noted that, in this embodiment, when calculating the pattern density in the final exposure layout, the main pattern 101, the first auxiliary pattern 102, and the second auxiliary pattern need to be considered. However, since the area of the sub-resolution second auxiliary pattern is small, its influence on the pattern density is negligible. Therefore, the pattern density calculated based on the intermediate layout is basically the same as the actual pattern density in the exposure layout.

[0055] In this embodiment, the method for establishing the optical proximity correction model considering pattern density includes: Step S201, setting N groups of OPC test patterns with different pattern densities, where N is greater than or equal to 2, and each group of OPC test patterns with different test pattern densities includes at least one test main pattern Pi and at least one test auxiliary pattern Ai arranged around the test main pattern Pi and having a different design distance from it.

[0056] Among them, the test pattern density includes local pattern density or global pattern density. And the local pattern density is the percentage of the sum of the areas of a plurality of the test auxiliary patterns Ai included in a preset area to the area of the preset area.

[0057] In this embodiment, during the process of building the optical proximity correction (OPC) model, since it is necessary to consider the influence of the test pattern density of other patterns near a pattern to be corrected in the test layout on the critical dimension (CD) of the corrected pattern, and this influence may be the influence of one or more patterns near the pattern to be corrected on its critical dimension in one-dimensional dimension, or it may be the influence on its critical dimension in the two-dimensional directions of X and Y within a region around the pattern to be corrected in the test layout. Based on this, the embodiments of the present invention provide an OPC modeling method for influencing the pattern to be corrected for various situations in the above two dimensions.

[0058] Please refer to Figure 6 , Method 1: Only consider the influence of the one-dimensional test pattern density of other patterns near the pattern to be corrected in the test layout on the critical dimension CD of the corrected pattern. Then the OPC test pattern in the OPC modeling is as follows: Assume that patterns P1, P2,..., Pi,..., Pn are test patterns equivalent to the pattern to be corrected in the test layout in the OPC modeling process, which are called test main patterns here, and the test pattern near the test main pattern Pi is the test auxiliary pattern Ai equivalent to the peripheral pattern near the pattern to be corrected in the test layout.

[0059] It should be noted that the modeling process is to expose multiple groups of sample data, analyze each group of sample data, and use multiple groups of sample data to correct the optical proximity correction model. Finally, the mapping relationship between the actual critical dimension of the test main pattern Pi on the silicon wafer and the change of the test pattern density of the OPC test pattern is obtained, that is, the optical proximity correction model is established.

[0060] As an example, when constructing the training sample data of the optical proximity correction model, a test auxiliary pattern Ai can be set near the test main pattern Pi, so as to form N groups of OPC test patterns with different one-dimensional test pattern densities by changing the area of the test auxiliary pattern Ai and the distance between it and the test main pattern Pi. Exemplarily, at least two groups of such pattern groups with different test pattern densities are required during the modeling process, that is, N is greater than or equal to 2. Please continue to refer to Figure 6 , in Figure 6 it exemplarily forms 5 groups of OPC test patterns, that is, A and P1, A and P2, A and P3, A and P4, and A and P5. Among them, in order to simplify the modeling process, the designed areas of the test main patterns P1 - P5 can be the same (the designed area is the theoretical area initially designed artificially in the test), and the distances between P1 - P5 and the auxiliary pattern A are all different. It can be understood that in Figure 6In the example, the areas of the auxiliary graphics A in the 5 groups of OPC test patterns are set to be the same, but they can be different in other embodiments.

[0061] Please refer to Figure 7 , Method 2: Only consider the influence of the critical dimensions of the graphics to be corrected in a region around the graphics to be corrected in the test layout in the two-dimensional directions of X and Y. Then, the OPC test patterns in the OPC modeling process can be as follows: Assume that the graphics P1, P2,..., Pi,..., Pn are the test patterns in the OPC modeling process that are equivalent to the graphics to be corrected in the test layout, and are called the test main graphics here. And all other test patterns in the region Ai around the test main graphic Pi are the auxiliary graphics equivalent to all the peripheral graphics included in the surrounding region Ai near the graphics to be corrected in the test layout.

[0062] It should be noted that since Method 2 considers the influence of all the graphics in a region framed around the test main graphic Pi on the test graphic density of the test main graphic Pi, therefore, in this process, the present invention exemplarily uses the ratio of the sum of the areas of all the graphics in the framed region to the area of this region as the test graphic density of the test pattern composed of this test main graphic Pi and the OPC test pattern. And since it is the sum of the areas of all the auxiliary graphics in the region Ai that is considered, the present invention does not specifically draw all the auxiliary graphics in Ai. Moreover, for a general description with the one-dimensional test graphic density, the present invention uses the region Ai to identify the surrounding region of the test main graphic Pi, and also uses the region Ai around the test main graphic Pi to identify the auxiliary graphics.

[0063] As an example, when constructing the training sample data of the optical proximity correction model, a region Ai can be framed near the test main graphic Pi, so as to form N groups of OPC test patterns with different two-dimensional test graphic densities by changing the area of the auxiliary graphics in the region Ai and the ratio of the area of the auxiliary graphics to the area of the region Ai. Exemplarily, at least two groups of graphic groups with different test graphic densities are required in the modeling process, that is, N is greater than or equal to 2. Please continue to refer to Figure 7 , in Figure 7 , 3 groups of OPC test patterns are exemplarily formed, that is, A1 and P1, A2 and P2, A3 and P3. Among them, in order to simplify the modeling process, the designed areas of the test main graphics P1 to P3 can be the same (the designed area is the theoretical area initially designed artificially in the test), and the sum of the areas of P1 to P3 and all the auxiliary graphics in the regions A1 to A3 and the area ratio between the two are all different.

[0064] Method 3: Consider the influence of one or more figures near the figure to be corrected on its critical dimension in one-dimensional dimension and the influence of the critical dimension of the figure to be corrected in a two-dimensional region along the X and Y directions around the figure to be corrected in the test layout, that is, combine the above Method 1 and Method 2.

[0065] It should be noted that in the above Method 1, Method 2, and Method 3, the designed area of the test auxiliary figure Ai needs to be greater than 10 times the critical dimension of the test main figure Pi after taking the square root, specifically, it can be 1 time, 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times, and 10 times. And the distance between the test main figure Pi and the test auxiliary figure Ai is at most not greater than 100 times the critical dimension of the test main figure Pi, that is, ≤ 100 times.

[0066] Step S202: Collect the wafer data of each group of OPC test figures with different test figure densities respectively. The wafer data includes the actual critical dimension of the test main figure Pi fabricated on the wafer, and establish a mapping relationship between the actual critical dimension of the test main figure Pi on the wafer and the change of the test figure density of the OPC test figure, that is, establish the optical proximity correction model.

[0067] In this embodiment, after forming N groups of test figures with different test figure densities by using the above step S201, each group of OPC test figures can be exposed on the wafer to obtain the actual critical dimension of the test main figure Pi fabricated on the wafer for each group of OPC test figures. Then, according to the actual critical dimension of the test main figure Pi fabricated on the wafer corresponding to these N groups of OPC test figures and their corresponding test figure densities, the mapping relationship between the actual critical dimension of the test main figure Pi on the wafer and the change of the test figure density of the OPC test figure can be determined, that is, establish the optical proximity correction model considering the test figure density in the modeling process proposed by the present invention.

[0068] As an example, the mapping relationship between the actual critical dimension of the test main figure Pi on the wafer and the change of the test figure density of the OPC test figure includes: the functional relationship between the actual critical dimension of the test main figure Pi on the wafer and the designed area of the test auxiliary figure Ai and the designed distance between the test main figure Pi and the test auxiliary figure Ai.

[0069] As another example, the mapping relationship in which the actual critical dimension of the test main pattern Pi on the silicon wafer changes with the change of the test pattern density of the OPC test pattern includes: the functional relationship in which the actual critical dimension of the test main pattern Pi on the silicon wafer changes with the ratio of the designed area of the test auxiliary pattern Ai to the area of the preset region within a preset region.

[0070] As other examples, the mapping relationship in which the actual critical dimension of the test main pattern Pi on the silicon wafer changes with the change of the test pattern density of the OPC test pattern includes: the functional relationship in which the actual critical dimension of the test main pattern Pi on the silicon wafer changes with the designed area of the test auxiliary pattern Ai and the designed distance between the test main pattern Pi and the test auxiliary pattern Ai, and the functional relationship in which the actual critical dimension of the test main pattern Pi on the silicon wafer changes with the ratio of the designed area of the test auxiliary pattern Ai to the area of the preset region within a preset region.

[0071] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. An optical proximity correction method, characterized in that, Including: Providing an initial layout, the initial layout including a plurality of main patterns; Generating a plurality of first auxiliary patterns around the main patterns to generate an intermediate layout; Obtaining a pattern density based on the intermediate layout; According to the pattern density, performing optical proximity correction using an optical proximity correction model considering the pattern density to generate a corrected layout.

2. The optical proximity correction method according to claim 1, wherein The main patterns are device patterns for generating actual functional devices, and the main patterns are exposed and developed on a photoresist layer.

3. The optical proximity correction method according to claim 1, wherein The first auxiliary patterns are generated in one or more ways based on rules and / or models.

4. The optical proximity correction method according to claim 1, characterized in that, The first auxiliary patterns are redundant patterns not for generating actual functional devices, and the first auxiliary patterns are exposed and developed on a photoresist layer.

5. The optical proximity correction method according to claim 1, wherein The method for obtaining the pattern density includes: establishing a scanning window for the pattern density, the scanning window covering the main patterns and the first auxiliary patterns; taking the ratio between the sum of the areas of all the main patterns and the first auxiliary patterns within the scanning window and the area of the scanning window as the pattern density.

6. The optical proximity correction method according to claim 4, wherein The method for performing optical proximity correction using the optical proximity correction model includes: excluding the first auxiliary patterns and performing optical proximity correction on the main patterns using the optical proximity correction model.

7. The optical proximity correction method according to claim 6, wherein The method for excluding the first auxiliary patterns and performing optical proximity correction on the main patterns using the optical proximity correction model includes: performing an exclusive OR operation on the initial layout and the intermediate layout to identify and mark the generated first auxiliary patterns; the optical proximity correction model performs optical proximity correction on the unmarked main patterns.

8. The optical proximity correction method according to claim 1, wherein The process of performing optical proximity correction using the optical proximity correction model includes: generating a plurality of second auxiliary patterns around the main patterns.

9. The optical proximity correction method according to claim 8, characterized in that, The second auxiliary patterns are sub-resolution patterns and are not exposed and developed on a photoresist layer.

10. The optical proximity correction method according to claim 1, characterized in that, After obtaining the corrected layout, it further includes: performing a mask rule check on the patterns in the corrected layout to generate an exposure layout.

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