Modeling method of optical proximity correction model and optical proximity correction method

Abstract

The present invention provides a modeling method of an optical proximity correction model and an optical proximity correction method based on the optical proximity correction model, which are applied to the field of semiconductor technology. Specifically, in the present invention, by adding variables related to the graphic density of a test pattern in the modeling process of an optical proximity correction model (OPC correction model), the established OPC model includes a mapping relationship between graphic key dimensions and graphic density-related variables, so as to propose a new OPC correction model. Afterwards, the OPC correction model is used to determine the distortion of the key dimensions of the test pattern in different graphic density environments, and then the distortion is compared with the design key dimensions of the test pattern to determine the correction amount of the test pattern in the OPC correction process, thereby improving the accuracy of the OPC correction process, thereby improving the process window of the layout and effectively improving the product yield.

Description

Technical Field

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

[0002] Optical proximity correction (OPC) technology has been widely used in the mass production of deep submicron integrated circuits. In the key layer publication below the 90nm technology node, the model-based OPC processing method is generally used. The basic principle of the model-based OPC processing method is to simulate the shape and size of the pattern after exposure or etching through the model, make corresponding corrections according to the deviation between the simulation data and the target data, and obtain the final mask pattern after several iterations.

[0003] In the process of establishing the existing OPC model, the correction model and menu do not reflect the actual impact of the graphic density on the accuracy of the graphic. Therefore, when the existing OPC model is built, there is no requirement for the graphic density when collecting data. When the photolithography process is close to the resolution limit, the impact of the graphic density, especially the local graphic density, cannot be ignored. Obviously, the existing OPC model that does not consider the graphic density is bound to have the problem that the critical size and process window of the corrected graphic cannot meet the design requirements. Summary of the invention

[0004] The object of the present invention is to provide a modeling method of an optical proximity correction model taking into account the density of a pattern and an optical proximity correction method based on the model, so as to achieve the purpose that the critical dimensions and process windows of the corrected pattern meet the design requirements and increase the stability of the product.

[0005] In a first aspect, in order to solve the above technical problems, the present invention provides a modeling method of an optical proximity correction model, and the modeling method may include:

[0006] Set N groups of OPC test patterns with different pattern densities, where N is greater than or equal to 2;

[0007] By using the OPC test pattern, an optical proximity correction model including a test pattern in which a critical dimension varies with pattern density is established.

[0008] Furthermore, each group of OPC test patterns with different pattern densities includes at least one main pattern P i And set in this main graphic P i At least one auxiliary pattern A around and having a different design distance from it i .

[0009] Further, the step of using the OPC test pattern to establish an optical proximity correction model including a test pattern whose critical dimension varies with pattern density may include:

[0010] The silicon wafer data of each group of OPC test patterns with different pattern densities are collected respectively, and the silicon wafer data includes the main pattern P i The actual critical dimensions on the silicon wafer are produced, and the main pattern P is established according to the silicon wafer data. i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern is used to establish the optical proximity correction model.

[0011] Further, the pattern density may include a local pattern density, or may include a global pattern density.

[0012] Furthermore, the local pattern density may be a plurality of auxiliary patterns A included in a preset area. i The percentage of the sum of the areas of the preset area.

[0013] Furthermore, the size of the preset area may be X*Y, the value range of X may be 30 nm-1000 nm, and the value range of Y may be 30 nm-1000 nm.

[0014] Furthermore, the main graphic P i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern may include:

[0015] The main graphic P i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary figure A i and / or, the main graphic P i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i The functional relationship changes with the change of the ratio of the design area to the area of ​​the preset area.

[0016] Furthermore, the auxiliary graphic A i The design area can be larger than the main figure P after the square root. i 10 times the critical size.

[0017] Furthermore, the main graphic P i With the auxiliary graphic A i The distance between the main figure Pi 100 times the critical dimension.

[0018] In a second aspect, based on the same inventive concept as the modeling method of the optical proximity correction model, the present invention further provides a modeling system of the optical proximity correction model. Specifically, the modeling system can be used to implement the modeling method of the optical proximity correction model as described above. The modeling system may include the following modules:

[0019] The OPC test pattern setting module is used to set N groups of OPC test patterns with different pattern densities, wherein N is greater than or equal to 2, and each group of OPC test patterns with different pattern densities includes at least one main pattern P i And set in the main graphic P i At least one auxiliary pattern A around and having a different design distance from it i ;

[0020] A model building module is used to collect the silicon wafer data of each group of OPC test patterns with different pattern densities, wherein the silicon wafer data includes the main pattern P i The actual critical dimensions on the silicon wafer are produced, and the main pattern P is established according to the silicon wafer data. i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern is used to establish the optical proximity correction model.

[0021] In a third aspect, based on the same inventive concept as the modeling method of the optical proximity correction model, the present invention further provides an optical proximity correction method, characterized in that the correction method may include the following steps:

[0022] Based on the modeling method of the optical proximity correction model as described above, a corresponding optical proximity correction model is formed, wherein the optical proximity correction model is an OPC correction model that increases a mapping relationship between variables related to a pattern key dimension and pattern density;

[0023] Determine a test layout corresponding to the pre-made layout, the test layout having at least one pattern to be corrected, and determine the pattern density of the pattern to be corrected in the test layout according to a preset pattern detection strategy;

[0024] Based on the determined mapping relationship between the pattern density and the optical proximity correction model, a critical dimension correction amount of the current optical proximity correction of the pattern to be corrected is determined, and optical proximity correction is performed on the pattern to be corrected based on the critical dimension correction amount.

[0025] Furthermore, there is a mapping relationship between the graphic key dimensions and graphic density related variables in the optical proximity correction model, which may include:

[0026] The main graphic P i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary figure A i and / or, the main graphic P i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i The functional relationship changes with the change of the ratio of the design area to the area of ​​the preset area.

[0027] Furthermore, the step of determining the pattern density of the pattern to be corrected in the test layout according to a preset pattern detection strategy may include:

[0028] The area of ​​the peripheral graphics of the graphics to be corrected is detected, and the area value of the peripheral graphics whose area is greater than a preset threshold and the distance value between the peripheral graphics and the graphics to be corrected are determined.

[0029] Further, based on the determined mapping relationship between the pattern density and the optical proximity correction model, the step of determining the critical dimension correction amount of the pattern to be corrected for the current optical proximity correction may include:

[0030] The area value and distance value are input into the main graph P in the optical proximity correction model. i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary figure A i The difference between the output value of the functional relationship and the design critical dimension of the pattern to be corrected is used as the critical dimension correction amount of the current optical proximity correction of the pattern to be corrected.

[0031] Furthermore, the step of determining the pattern density of the pattern to be corrected in the test layout according to a preset pattern detection strategy may include:

[0032] A preset area is set around the figure to be corrected, wherein the preset area includes the figure to be corrected and a plurality of other surrounding figures that are at a certain distance from the figure to be corrected;

[0033] The area of ​​the preset region and the sum of the areas of all surrounding graphics contained in the preset region except the graphics to be corrected are determined.

[0034] Further, based on the determined mapping relationship between the pattern density and the optical proximity correction model, the step of determining the critical dimension correction amount of the pattern to be corrected for the current optical proximity correction may include:

[0035] The sum of the area of ​​the preset region and the area of ​​all other peripheral graphics contained in the preset region except the graphics to be corrected is input into the main graphics P in the optical proximity correction model. i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i A functional relationship is formed in which the ratio of the design area to the area of ​​the preset area changes, and the difference between the output value of the functional relationship and the design key size of the to-be-corrected graphic is used as the key size correction amount of the current optical proximity correction of the to-be-corrected graphic.

[0036] Further, based on the determined mapping relationship between the pattern density and the optical proximity correction model, the step of determining the critical dimension correction amount of the pattern to be corrected for the current optical proximity correction may include:

[0037] The area value, the distance value, the area of ​​the preset area and the sum of the areas of all other surrounding graphics contained in the preset area except the graphic to be corrected are used as the input of the optical proximity correction model, and the output of the optical proximity correction model is used as the difference with the design critical dimension of the graphic to be corrected as the critical dimension correction amount of this optical proximity correction of the graphic to be corrected.

[0038] Furthermore, the square root of the area of ​​the peripheral figure of the figure to be corrected may be greater than 10 times the critical size of the figure to be corrected.

[0039] Furthermore, the distance between the peripheral pattern and the pattern to be corrected may be no greater than 100 times the critical dimension of the pattern to be corrected.

[0040] In a fourth aspect, based on the same inventive concept as the optical proximity correction method, the present invention further provides an optical proximity correction system, characterized in that, specifically, the correction system can be used to implement the optical proximity correction method as described above, and the correction system includes the following modules:

[0041] A modeling module, for forming a corresponding optical proximity correction model based on the modeling method of the optical proximity correction model according to any one of claims 1 to 7, wherein the optical proximity correction model is an OPC correction model that increases a mapping relationship between graphic key dimensions and graphic density-related variables;

[0042] A pattern density determination module, used to determine a test layout corresponding to a pre-made layout, the test layout having at least one pattern to be corrected, and determine the pattern density of the pattern to be corrected in the test layout according to a preset pattern detection strategy;

[0043] The correction module is used to determine the critical size correction amount of the current optical proximity correction of the graphic to be corrected based on the determined graphic density and the mapping relationship in the optical proximity correction model, and perform optical proximity correction on the graphic to be corrected based on the critical size correction amount.

[0044] In a fifth aspect, based on the modeling method of the optical proximity correction model and the optical proximity correction method as described above, the present invention further provides an electronic device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus;

[0045] Memory, used to store computer programs;

[0046] The processor is used to implement the above-mentioned method for modeling the optical proximity correction model or the steps of the optical proximity correction method when executing the program stored in the memory.

[0047] In a sixth aspect, an embodiment of the present invention further provides a computer-readable storage medium, wherein a computer program is stored in the computer-readable storage medium, and when the computer program is executed by a processor, the modeling method of the above-mentioned optical proximity correction model or the steps of the optical proximity correction method are implemented.

[0048] Compared with the prior art, the technical solution provided by the present invention has at least one of the following beneficial effects:

[0049] The present invention provides a modeling method of an optical proximity correction model and an optical proximity correction method based on the optical proximity correction model, which adds variables related to the pattern density of a test pattern in the modeling process of the optical proximity correction model (OPC model), so that the established OPC model contains a mapping relationship between the pattern key size and the pattern density related variables, so as to propose a new OPC model. Afterwards, the OPC model is used to determine the distortion of the key size of the test pattern in different pattern density environments, and then the distortion is compared with the design key size of the test pattern to determine the correction amount of the test pattern in the OPC correction process, thereby improving the accuracy in the OPC correction process, thereby improving the process window of the layout and effectively improving the product yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is a schematic flow chart of a method for modeling an optical proximity correction model in one embodiment of the present invention;

[0051] Figure 2 The OPC test pattern provided in one embodiment of the present invention is a structural schematic diagram in which an auxiliary pattern is arranged near a main pattern to consider the influence of a one-dimensional pattern density near the test pattern on its critical dimension;

[0052] Figure 3 A schematic diagram of a structure in which an OPC test pattern provided in one embodiment of the present invention is framed around a main pattern to set an area, so as to consider the influence of the two-dimensional pattern density of the area around the test pattern on its critical dimension;

[0053] Figure 4 A schematic diagram of the structure of a modeling system of an optical proximity correction model provided in one embodiment of the present invention;

[0054] Figure 5 is a schematic flow chart of an optical proximity correction method in one embodiment of the present invention;

[0055] Figure 6 FIG. 4 is a schematic diagram of the structure of an optical proximity correction system in one embodiment of the present invention. DETAILED DESCRIPTION

[0056] As described in the background art, in the process of establishing the existing OPC model, the actual influence of the pattern density on the pattern accuracy is not reflected in the correction model and the menu. Therefore, when the existing OPC model is built, there is no requirement for the pattern density when collecting data. When the photolithography process approaches the resolution limit, the influence of the pattern density, especially the local pattern density, cannot be ignored. Obviously, the existing OPC model that does not consider the pattern density is bound to have the problem that the critical size and process window of the corrected pattern cannot meet the design requirements.

[0057] To this end, the inventors of the present invention propose that in the modeling process of the OPC correction model, a group of variables related to the graphic density can be first set, and then, by analyzing the sample simulation data corresponding to the set N groups of OPC test graphics, a mapping relationship between the target correction parameters and the graphic density-related variables can be obtained, that is, an OPC correction model with added graphic density variables is established, and based on the OPC correction model and the collected graphic density of a target graphic to be corrected that is changed by changes in other graphics around it, the target correction amount of the target graphic to be corrected, for example, the critical dimension CD, is determined.

[0058] Based on this theory, the present invention provides a modeling method of an optical proximity correction model that takes into account graphic density and an optical proximity correction method based on the model, so as to achieve the purpose that the critical dimensions and process windows of the corrected graphics meet the design requirements and increase the stability of the product.

[0059] The modeling method of the optical proximity correction model considering the density of the graphics proposed by the present invention and the optical proximity correction method based on the model are further described in detail below in conjunction with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will become clearer. It should be noted that the accompanying drawings are all in a very simplified form and are not in precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention can also be implemented in other ways different from those described herein, so the present invention is not limited to the specific embodiments disclosed below.

[0060] As shown in this application and the claims, unless the context clearly indicates an exception, the words "a", "an", "a kind" and / or "the" do not specifically refer to the singular, but may also include the plural. Generally speaking, the terms "include" and "comprise" only indicate the inclusion of clearly identified steps and elements, and these steps and elements do not constitute an exclusive list, and the method or device may also include other steps or elements. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional view showing the device structure will not be partially enlarged according to the general proportion, and the schematic diagram is only an example, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional spatial dimensions of length, width and depth should be included.

[0061] The following first introduces in detail a modeling method of an optical proximity correction model provided by the present invention. Figure 1 , Figure 1 The figure is a flow chart of a method for modeling an optical proximity correction model provided in one embodiment of the present invention, the method comprising the following steps:

[0062] Step S101, setting N groups of OPC test patterns with different pattern densities, wherein N is greater than or equal to 2, and each group of OPC test patterns with different pattern densities includes at least one main pattern P i And set in this main graphic P i At least one auxiliary pattern A around and having a different design distance from it i .

[0063] The pattern density includes local pattern density or global pattern density. The local pattern density is the density of the auxiliary patterns A contained in a preset area. iExemplarily, the size of the preset area is X*Y, and the value range of X is 30nm-1000nm, that is, 30nm, 40nm, 50nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm and 1000nm, or 30nm / 40nm / 50nm~100nm, 100nm~200nm / 300nm / 400nm / 500nm / 600nm / 700nm / 800nm / 900nm / 1000nm, and any other two endpoint values ​​mentioned above Similarly, the value range of Y is 30nm-1000nm, that is, 30nm, 40nm, 50nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm and 1000nm, or 30nm / 40nm / 50nm~100nm, 100nm~200nm / 300nm / 400nm / 500nm / 600nm / 700nm / 800nm / 900nm / 1000nm, and the interval range composed of any other two endpoint values ​​mentioned above.

[0064] In this embodiment, during the modeling process of the OPC model, it is necessary to consider the influence of other graphics near a to-be-corrected graphic in the test layout on the graphic density of the to-be-corrected graphic on the critical dimension CD of the corrected graphic, and the influence may be the influence of one or more graphics near the to-be-corrected graphic on its critical dimension in one dimension, or the influence of an area around the to-be-corrected graphic in the test layout along the two-dimensional directions of X and Y on its critical dimension. Based on this, the embodiment of the present invention provides an OPC modeling method for influencing the to-be-corrected graphic in multiple situations in the above two dimensions.

[0065] Method 1: Only consider the influence of other graphics near the graphics to be corrected in the test layout on the one-dimensional pattern density of the graphics to be corrected on the critical dimension CD of the corrected graphics. Then the OPC test pattern in OPC modeling is: Figure 2 As shown, assuming that the graph P 1 , P 2 ...、P i , ..., P n It is a test pattern in the OPC modeling process that is equivalent to the test pattern to be corrected in the test layout. It is called the main pattern here, and the main pattern P i The test pattern near is an auxiliary pattern A which is equivalent to the surrounding pattern near the pattern to be corrected in the test layout. i .

[0066] It should be noted that the modeling process is to expose multiple sets of sample data, analyze each set of sample data, and use the multiple sets of sample data to calibrate the OPC model, and finally obtain the main graph P i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern is used to establish the OPC model.

[0067] As an example, when constructing the training sample data of the OPC model, the main graph P i Set an auxiliary figure A near i , thus by changing the auxiliary graph A i The area of ​​the main figure P i N groups of OPC test patterns with one-dimensional different pattern densities are formed by the distance between them. Exemplarily, at least two groups of such patterns with different pattern densities are required in the modeling process, that is, N is greater than or equal to 2. Figure 2 As shown, in Figure 2 In the example, five groups of OPC test patterns are formed, namely, A and P 1 , A and P 2 , A and P 3 , A and P 4 and A and P 5 In order to simplify the modeling process, the main graph P 1 ~P 5 The design area can be the same (the design area is the theoretical area designed initially in the test), and P 1 ~P 5 The distances between the auxiliary figure A and the auxiliary figure A are all different. It can be understood that Figure 2 In the figure, the areas of the auxiliary patterns A in the five groups of OPC test patterns are set to be the same for example, and they may be different in other embodiments.

[0068] Method 2: Only consider the influence of the critical dimension in the two-dimensional directions of X and Y in an area around the pattern to be corrected in the test layout. Then the OPC test pattern in the OPC modeling process can be: Figure 3 As shown, assuming that the graph P 1 , P 2 ...、P i , ..., P n It is a test pattern in the OPC modeling process that is equivalent to the test pattern to be corrected in the test layout. It is called the main pattern here, and the main pattern P i Surrounding area A i All other test patterns in the test layout are equivalent to the surrounding area A around the pattern to be corrected in the test layout. iAuxiliary graphics for all surrounding graphics contained in .

[0069] It should be noted that, since the second method takes into account the main graph P i All the graphics in the area framed by the main graphics P i Therefore, in this process, the present invention exemplarily takes the ratio of the area of ​​all graphics in the framed area to the area of ​​the area as the ratio of the area of ​​the main graphic P i The test pattern composed of is used as the pattern density of the OPC test pattern. And, since the area A is considered i The sum of the areas of all auxiliary graphics within A. Therefore, the present invention does not specifically define A as i In order to describe the density of the one-dimensional pattern in a general way, the present invention draws all the auxiliary patterns in the main pattern P i The surrounding area is A i Logo, and the auxiliary graphics also use the main graphics P i Surrounding area A i Logo.

[0070] As an example, when constructing the training sample data of the OPC model, the main graph P i Set the area around the area A i , thus by changing the area A i The area of ​​the auxiliary figure and its relationship with area A i N groups of OPC test patterns with two-dimensional different pattern densities are formed by the ratio of the area of ​​the two-dimensional OPC test patterns. Exemplarily, at least two groups of such patterns with different pattern densities are required in the modeling process, that is, N is greater than or equal to 2. Figure 3 As shown, in Figure 3 In the example, three groups of OPC test patterns are formed, namely, A 1 and P 1 , A 2 and P 2 , A 3 and P 3 In order to simplify the modeling process, the main graph P 1 ~P 3 The design area can be the same (the design area is the theoretical area designed initially in the test), and P 1 ~P 3 With area A 1 ~A 3 The sum of the areas of all auxiliary figures within and the ratio of the areas between them are different.

[0071] Method three, simultaneously considering the influence of one or more patterns near the pattern to be corrected on its critical size in one dimension and the influence of an area around the pattern to be corrected in the test layout along the two-dimensional directions of X and Y on its critical size, that is, combining the above methods one and two.

[0072] It should be noted that in the above-mentioned methods 1, 2 and 3, the auxiliary graphics A i The design area needs to be larger than the main figure P after the square root. i 10 times of the key size, specifically 1 time, 2 times, 3 times, 4 times, 5 times, 6 times, 7 times, 8 times, 9 times and 10 times. i With the auxiliary graphic A i The maximum distance between them is not greater than the main figure P i 100 times the critical dimension of, that is, ≤100 times.

[0073] Step S102, respectively collecting the silicon wafer data of each group of OPC test patterns with different pattern densities, wherein the silicon wafer data includes the main pattern P i The actual critical dimensions on the silicon wafer are produced, and the main pattern P is established according to the silicon wafer data. i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern is used to establish the optical proximity correction model.

[0074] In this embodiment, after forming N groups of test patterns with different pattern densities by using the above step S101, each group of OPC test patterns can be exposed on a silicon wafer to obtain a main pattern P for each group of OPC test patterns. i Then, according to the main pattern P corresponding to these N groups of OPC test patterns, i The actual critical dimensions and the corresponding pattern density made on the silicon wafer can determine the main pattern P i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern is used to establish the optical proximity correction model (OPC correction model) that takes the pattern density into consideration in the modeling process proposed by the present invention.

[0075] As an example, the main graphic P i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern varies, including: the main pattern P i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary figure A iThe functional relationship between the design distance and the

[0076] As another example, the main graphic P i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern varies, including: the main pattern P i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i The functional relationship changes with the change of the ratio of the design area to the area of ​​the preset area.

[0077] As another example, the main graphic P i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern varies, including: the main pattern P i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary figure A i The functional relationship between the design distance and the main graph P i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i The functional relationship changes with the change of the ratio of the design area to the area of ​​the preset area.

[0078] Because in the present invention, by adding variables related to the pattern density of the test pattern in the modeling process of the optical proximity correction model (OPC correction model), the established OPC correction model includes a mapping relationship between the pattern key size and the pattern density related variables, so as to propose a new type of OPC correction model. It can be understood that the inventive theory of the present invention is to propose a theory that considers the correction effect of the pattern density related variables on the pattern key size in the process of modeling the OPC correction model, and the above-mentioned mapping relationship is only a few exemplary cases proposed by the present invention, and as long as the modeling method that considers the correction effect of the pattern density related variables on the pattern key size in the process of modeling the OPC correction model belongs to the protection scope of the present invention.

[0079] Based on the modeling method of the optical proximity correction model as described above, this embodiment also provides a modeling system of the optical proximity correction model. Figure 4 , Figure 4 FIG. 1 is a schematic diagram of the structure of a modeling system of an optical proximity correction model in an embodiment of the present invention, wherein the modeling system comprises:

[0080] The OPC test pattern setting module 401 is used to set N groups of OPC test patterns with different pattern densities, wherein N is greater than or equal to 2, and each group of OPC test patterns with different pattern densities includes at least one main pattern P i And set in this main graphic P i At least one auxiliary pattern A around and having a different design distance from it i ;

[0081] The model building module 402 is used to collect the silicon wafer data of each group of OPC test patterns with different pattern densities, wherein the silicon wafer data includes the main pattern P i The actual critical dimensions on the silicon wafer are produced, and the main pattern P is established according to the silicon wafer data. i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern is used to establish the optical proximity correction model.

[0082] Further, based on the same inventive concept as the modeling method of the optical proximity correction model, the present invention also provides a correction method based on the optical proximity correction model, such as Figure 5 Specifically, the correction method may include the following steps:

[0083] Step S501 : Based on the modeling method of the optical proximity correction model as described above, a corresponding optical proximity correction model is formed, wherein the optical proximity correction model is an OPC correction model that increases a mapping relationship between pattern critical dimensions and pattern density-related variables.

[0084] There is a mapping relationship between the key size of the graphics and the graphics density related variables in the optical proximity correction model, including: the main graphics P i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary figure A i and / or, the main graphic P i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i The functional relationship changes with the change of the ratio of the design area to the area of ​​the preset area.

[0085] Step S502, determining a test layout corresponding to the pre-fabricated layout, wherein the test layout has at least one pattern to be corrected, and determining the pattern density of the pattern to be corrected in the test layout according to a preset pattern detection strategy.

[0086] In this embodiment, after establishing the OPC correction model in which the mapping relationship between the increased graphic key size and the graphic density-related variables exists, the test layout to be corrected can be determined, wherein the test layout can contain multiple graphics to be corrected. As an example, the present invention will introduce a process of how to correct a graphic to be corrected in the test layout using the OPC correction model formed by the present invention. Since the OPC correction model formed by the modeling method provided by the present invention can be an OPC correction model based on a one-dimensional relationship of graphic density, an OPC correction model based on a two-dimensional relationship of graphic density, or an OPC correction model based on both a one-dimensional and a two-dimensional relationship of graphic density, in the embodiment of the present invention, for different graphic density situations, there can be the following three ways to determine the graphic density of the graphic to be corrected.

[0087] Method 1: Detect the area of ​​the surrounding graphics of the graphic to be corrected, determine the area value of the surrounding graphics whose area is greater than a preset threshold and the distance value between the surrounding graphics and the graphic to be corrected.

[0088] Method 2: setting a preset area around the figure to be corrected, wherein the preset area includes the figure to be corrected and a plurality of other surrounding figures that are at a certain distance from the figure to be corrected; determining the area of ​​the preset area and the sum of the areas of all other surrounding figures included in the preset area except the figure to be corrected.

[0089] Method three, first detect the area of ​​the surrounding graphics of the graphic to be corrected, determine the area value of the surrounding graphics whose area is greater than a preset threshold and the distance value between the surrounding graphics and the graphic to be corrected, and then set a preset area around the graphic to be corrected, the preset area includes the graphic to be corrected and includes multiple other surrounding graphics that form a certain distance with the graphic to be corrected; determine the area of ​​the preset area, and the sum of the areas of all other surrounding graphics contained in the preset area except the graphic to be corrected.

[0090] It should be noted that the graphic detection strategy used in the above-mentioned methods 1, 2 and 3 may be an existing algorithm in the OPC correction model menu for calculating the distance of a large-area graphic around a graphic and / or the density of a graphic within a certain range around a graphic.

[0091] Step S503, determining a critical dimension correction amount of the current optical proximity correction of the pattern to be corrected based on the determined pattern density and the mapping relationship in the optical proximity correction model, and performing optical proximity correction on the pattern to be corrected based on the critical dimension correction amount.

[0092] In this embodiment, after the graphic density of the graphic to be corrected is determined by using the above step S502, that is, the area value of the surrounding graphics whose area is greater than the preset threshold, the distance value between the surrounding graphics and the graphic to be corrected (first graphic density); and / or, after determining the area of ​​the preset area, and the sum of the areas of all other surrounding graphics contained in the preset area except the graphic to be corrected (second graphic density), the above first graphic density and / or second graphic density can be input into the OPC correction model formed by the present invention, so as to determine the critical size correction amount of the optical proximity correction of the graphic to be corrected, and perform optical proximity correction on the graphic to be corrected based on the critical size correction amount.

[0093] Specifically, the area value and the distance value may be input into the main graph P in the optical proximity correction model. i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary figure A i The difference between the output value of the functional relationship and the design critical dimension of the pattern to be corrected is used as the critical dimension correction amount of the current optical proximity correction of the pattern to be corrected.

[0094] Alternatively, the sum of the area of ​​the preset region and the area of ​​all other peripheral graphics contained in the preset region except the graphics to be corrected is input into the main graphics P in the optical proximity correction model. i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i A functional relationship is formed in which the ratio of the design area to the area of ​​the preset area changes, and the difference between the output value of the functional relationship and the design key size of the to-be-corrected graphic is used as the key size correction amount of the current optical proximity correction of the to-be-corrected graphic.

[0095] Alternatively, the area value, the distance value, the area of ​​the preset area and the sum of the areas of all other surrounding graphics contained in the preset area except the graphic to be corrected are used as the input of the optical proximity correction model, and the output of the optical proximity correction model is used as the difference between the design critical dimension of the graphic to be corrected and the critical dimension correction amount of this optical proximity correction of the graphic to be corrected.

[0096] The square root of the area of ​​the peripheral figure of the figure to be corrected is greater than 10 times the critical size of the figure to be corrected. The distance between the peripheral figure and the figure to be corrected is not greater than 100 times the critical size of the figure to be corrected.

[0097] In the optical proximity correction method provided by the present invention, the OPC correction model is used to determine the distortion of the key dimensions of the test pattern in different graphic density environments, and then the distortion is compared with the design key dimensions of the test pattern to determine the correction amount of the test pattern in the OPC correction process, thereby improving the accuracy of the OPC correction process, thereby improving the process window of the layout and effectively improving the product yield.

[0098] Similarly, based on the optical proximity correction method described above, the present invention also provides an optical proximity correction system, wherein the correction system is used to implement the optical proximity correction method, specifically, refer to Figure 6 As shown, the correction system provided by the present invention may include:

[0099] The modeling module 601 is used to form a corresponding optical proximity correction model based on the modeling method of the optical proximity correction model as described above, wherein the optical proximity correction model is an OPC correction model that increases the mapping relationship between graphic key dimensions and graphic density related variables.

[0100] The pattern density determination module 602 is used to determine a test layout corresponding to the pre-made layout, the test layout having at least one pattern to be corrected, and determine the pattern density of the pattern to be corrected in the test layout according to a preset pattern detection strategy.

[0101] The correction module 603 is used to determine the critical size correction amount of the current optical proximity correction of the graphic to be corrected based on the determined graphic density and the mapping relationship in the optical proximity correction model, and perform optical proximity correction on the graphic to be corrected based on the critical size correction amount.

[0102] In summary, in the present invention, by adding variables related to the pattern density of the test pattern in the modeling process of the optical proximity correction model (OPC correction model), the established OPC correction model includes a mapping relationship between the pattern key size and the pattern density related variables, so as to propose a new OPC correction model. Afterwards, the OPC correction model is used to determine the distortion of the key size of the test pattern in different pattern density environments, and then the distortion is compared with the design key size of the test pattern to determine the correction amount of the test pattern in the OPC correction process, thereby improving the accuracy of the OPC correction process, thereby improving the process window of the layout and effectively improving the product yield.

[0103] An embodiment of the present invention further provides an electronic device, including a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus.

[0104] Memory, used to store computer programs;

[0105] The processor is used to implement a modeling method of an optical proximity correction model or a model-based optical proximity correction method provided by an embodiment of the present invention when executing a program stored in the memory.

[0106] Specifically, a modeling method of an optical proximity correction model includes:

[0107] N groups of OPC test patterns with different pattern densities are set, wherein N is greater than or equal to 2, and each group of OPC test patterns with different pattern densities includes at least one main pattern P i And set in this main graphic P i At least one auxiliary pattern A around and having a different design distance from it i ;

[0108] The silicon wafer data of each group of OPC test patterns with different pattern densities are collected respectively, and the silicon wafer data includes the main pattern P i The actual critical dimensions on the silicon wafer are produced, and the main pattern P is established according to the silicon wafer data. i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern is used to establish the optical proximity correction model.

[0109] And, an optical proximity correction method, the correction method comprising:

[0110] Based on the modeling method of the optical proximity correction model as described above, a corresponding optical proximity correction model is formed, wherein the optical proximity correction model is an OPC correction model that increases a mapping relationship between variables related to a pattern key dimension and pattern density;

[0111] Determine a test layout corresponding to the pre-made layout, the test layout having at least one pattern to be corrected, and determine the pattern density of the pattern to be corrected in the test layout according to a preset pattern detection strategy;

[0112] Based on the determined mapping relationship between the pattern density and the optical proximity correction model, a critical dimension correction amount of the current optical proximity correction of the pattern to be corrected is determined, and optical proximity correction is performed on the pattern to be corrected based on the critical dimension correction amount.

[0113] In addition, the modeling method of the optical proximity correction model or other implementation methods of the optical proximity correction method implemented by the processor executing the program stored in the memory are the same as the implementation methods mentioned in the aforementioned method embodiment part, and will not be repeated here.

[0114] The communication bus mentioned in the control terminal can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The communication bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or one type of bus.

[0115] The communication interface is used for communication between the above electronic device and other devices.

[0116] The memory may include a random access memory (RAM) or a non-volatile memory (NVM), such as at least one disk memory. Optionally, the memory may also be at least one storage device located away from the aforementioned processor.

[0117] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0118] In another embodiment provided by the present invention, a computer-readable storage medium is also provided, which stores instructions. When the computer-readable storage medium is run on a computer, the computer executes the modeling method of the optical proximity correction model or the optical proximity correction method described in any of the above embodiments.

[0119] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in the embodiment of the present invention is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk Solid State Disk (SSD)), etc.

[0120] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0121] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device, electronic device, and computer-readable storage medium embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiments.

[0122] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A method for modeling an optical proximity correction model, characterized in that: The modeling method comprises: N groups of OPC test patterns with different pattern densities are set, wherein N is greater than or equal to 2, and each group of OPC test patterns with different pattern densities includes at least one main pattern P i And set in the main graphic P i At least one auxiliary pattern A around and having a different design distance from it i ; The silicon wafer data of each group of OPC test patterns with different pattern densities are collected respectively, and the silicon wafer data includes the main pattern P i The actual critical dimensions on the silicon wafer are produced, and the main pattern P is established according to the silicon wafer data. i A mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern is established, that is, the optical proximity correction model is established; Among them, the main graphic P i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern includes: The main graphic P i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary graphic A i and / or, the main graphic P i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i The functional relationship changes with the change of the ratio of the design area to the area of ​​the preset area.

2. The method for modeling an optical proximity correction model according to claim 1, wherein: The pattern density includes a local pattern density or a global pattern density.

3. The method for modeling an optical proximity correction model according to claim 2, wherein: The local pattern density is a plurality of auxiliary patterns A included in a preset area. i The percentage of the sum of the areas of the preset area.

4. The method for modeling an optical proximity correction model according to claim 3, wherein: The size of the preset area is X*Y, the value range of X is 30nm-1000nm, and the value range of Y is 30nm-1000nm.

5. The method for modeling an optical proximity correction model according to claim 4, wherein: The auxiliary graphic A i The design area after square root is larger than the main figure P i 10 times the critical size.

6. The method for modeling an optical proximity correction model according to claim 3, wherein: The main graphic P i With the auxiliary graphic A i The distance between them is no greater than the main figure P i 100 times the critical dimension.

7. A modeling system for an optical proximity correction model, characterized in that: The modeling system is used to implement the modeling method of the optical proximity correction model according to any one of claims 1 to 6, and the modeling system comprises: The OPC test pattern setting module is used to set N groups of OPC test patterns with different pattern densities, wherein N is greater than or equal to 2, and each group of OPC test patterns with different pattern densities includes at least one main pattern P i And set in the main graphic P i At least one auxiliary pattern A around and having a different design distance from it i ; A model building module is used to collect the silicon wafer data of each group of OPC test patterns with different pattern densities, wherein the silicon wafer data includes the main pattern P i The actual critical dimensions on the silicon wafer are produced, and the main pattern P is established according to the silicon wafer data. i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern is established, that is, the optical proximity correction model is established, wherein the main pattern P i The mapping relationship between the actual critical dimension on the silicon wafer and the pattern density of the OPC test pattern varies, including: the main pattern P i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary graphic A i and / or, the main graphic P i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i The functional relationship changes with the change of the ratio of the design area to the area of ​​the preset area.

8. An optical proximity correction method, characterized in that: The correction method comprises: Based on the modeling method of the optical proximity correction model described in any one of claims 1 to 6, a corresponding optical proximity correction model is formed, wherein the optical proximity correction model is an OPC correction model that increases a mapping relationship between graphic key dimensions and graphic density-related variables; Determine a test layout corresponding to the pre-made layout, the test layout having at least one pattern to be corrected, and determine the pattern density of the pattern to be corrected in the test layout according to a preset pattern detection strategy; Determine a critical dimension correction amount of the current optical proximity correction of the pattern to be corrected based on the determined mapping relationship between the pattern density and the optical proximity correction model, and perform optical proximity correction on the pattern to be corrected based on the critical dimension correction amount; There is a mapping relationship between the key size of the graphics and the graphics density related variables in the optical proximity correction model, including: the main graphics P i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary graphic A i and / or, the main graphic P i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i The functional relationship changes with the change of the ratio of the design area to the area of ​​the preset area.

9. The optical proximity correction method according to claim 8, wherein: The step of determining the pattern density of the pattern to be corrected in the test layout according to a preset pattern detection strategy includes: The area of ​​the peripheral graphics of the graphics to be corrected is detected, and the area value of the peripheral graphics whose area is greater than a preset threshold and the distance value between the peripheral graphics and the graphics to be corrected are determined.

10. The optical proximity correction method according to claim 9, wherein: The step of determining a critical dimension correction amount of the current optical proximity correction of the pattern to be corrected based on the determined mapping relationship between the pattern density and the optical proximity correction model comprises: The area value and distance value are input into the main graph P in the optical proximity correction model. i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary graphic A i The difference between the output value of the functional relationship and the design critical dimension of the pattern to be corrected is used as the critical dimension correction amount of the current optical proximity correction of the pattern to be corrected.

11. The optical proximity correction method according to claim 8, wherein: The step of determining the pattern density of the pattern to be corrected in the test layout according to a preset pattern detection strategy includes: A preset area is set around the figure to be corrected, wherein the preset area includes the figure to be corrected and a plurality of other surrounding figures that are at a certain distance from the figure to be corrected; The area of ​​the preset region and the sum of the areas of all surrounding graphics contained in the preset region except the graphics to be corrected are determined.

12. The optical proximity correction method according to claim 11, wherein: The step of determining a critical dimension correction amount of the current optical proximity correction of the pattern to be corrected based on the determined mapping relationship between the pattern density and the optical proximity correction model comprises: The sum of the area of ​​the preset region and the area of ​​all other peripheral graphics contained in the preset region except the graphics to be corrected is input into the main graphics P in the optical proximity correction model. i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i A functional relationship is formed in which the ratio of the design area to the area of ​​the preset area changes, and the difference between the output value of the functional relationship and the design key size of the to-be-corrected graphic is used as the key size correction amount of the current optical proximity correction of the to-be-corrected graphic.

13. The optical proximity correction method according to claim 9, wherein: The square root of the area of ​​the peripheral figure of the figure to be corrected is greater than 10 times the critical size of the figure to be corrected.

14. The optical proximity correction method according to claim 13, wherein: The distance between the peripheral pattern and the pattern to be corrected is not greater than 100 times the critical dimension of the pattern to be corrected.

15. An optical proximity correction method, characterized in that: The correction method comprises: Based on the modeling method of the optical proximity correction model described in any one of claims 1 to 6, a corresponding optical proximity correction model is formed, wherein the optical proximity correction model is an OPC correction model that increases a mapping relationship between graphic key dimensions and graphic density-related variables; Determine a test layout corresponding to the pre-made layout, the test layout having at least one pattern to be corrected, and determine the pattern density of the pattern to be corrected in the test layout according to a preset pattern detection strategy; wherein the step of determining the pattern density of the pattern to be corrected in the test layout according to the preset pattern detection strategy comprises: detecting the area of ​​the peripheral patterns of the pattern to be corrected, determining the area value of the peripheral patterns whose area is greater than a preset threshold and the distance value between the peripheral patterns and the pattern to be corrected; and, setting a preset area around the pattern to be corrected, the preset area includes the pattern to be corrected and includes a plurality of other peripheral patterns that form a certain distance with the pattern to be corrected, and determining the area of ​​the preset area and the sum of the areas of all other peripheral patterns contained in the preset area except the pattern to be corrected; Based on the determined mapping relationship between the pattern density and the optical proximity correction model, a critical size correction amount of the current optical proximity correction of the pattern to be corrected is determined, and optical proximity correction is performed on the pattern to be corrected based on the critical size correction amount; wherein there is a mapping relationship between the pattern critical size and pattern density related variables in the optical proximity correction model, including: the main pattern P i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary graphic A i and / or, the main graphic P i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i The step of determining the critical dimension correction amount of the current optical proximity correction of the graphic to be corrected based on the determined pattern density and the mapping relationship in the optical proximity correction model comprises: The area value, the distance value, the area of ​​the preset area and the sum of the areas of all other surrounding graphics contained in the preset area except the graphic to be corrected are used as the input of the optical proximity correction model, and the output of the optical proximity correction model is used as the difference with the design critical dimension of the graphic to be corrected as the critical dimension correction amount of this optical proximity correction of the graphic to be corrected.

16. An optical proximity correction system, characterized in that: The correction system is used to implement the optical proximity correction method described in any one of claims 8 to 15, and the correction system comprises: A modeling module, for forming a corresponding optical proximity correction model based on the modeling method of the optical proximity correction model according to any one of claims 1 to 6, wherein the optical proximity correction model is an OPC correction model that increases a mapping relationship between graphic key dimensions and graphic density-related variables; A pattern density determination module, used to determine a test layout corresponding to a pre-made layout, the test layout having at least one pattern to be corrected, and determine the pattern density of the pattern to be corrected in the test layout according to a preset pattern detection strategy; a correction module, configured to determine a critical dimension correction amount of the current optical proximity correction of the graphic to be corrected based on the determined graphic density and a mapping relationship in the optical proximity correction model, and perform optical proximity correction on the graphic to be corrected based on the critical dimension correction amount; There is a mapping relationship between the key size of the graphics and the graphics density related variables in the optical proximity correction model, including: the main graphics P i The actual critical dimension on the silicon wafer varies with the auxiliary pattern A i The design area and main graphic P i With auxiliary graphic A i and / or, the main graphic P i The actual critical dimension on the silicon wafer is determined by the auxiliary pattern A in a predetermined area. i The functional relationship changes with the change of the ratio of the design area to the area of ​​the preset area.

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