A method for determining the thickness of an anti-reflection layer

Abstract

The present application provides a method for determining the thickness of an anti-reflection layer, wherein the method includes: obtaining a graphic file of a target area graphic corresponding to a wafer to be exposed; obtaining at least one preset window graphic and a preset anti-reflection layer thickness corresponding to the target area graphic respectively; inputting the graphic file and the preset anti-reflection layer thickness into an optical proximity correction model to perform optical simulation, and obtaining a simulation curve of light intensity corresponding to each preset anti-reflection layer thickness changing with coordinates; in the simulation curve corresponding to each preset anti-reflection layer thickness, determining a target curve slope corresponding to preset position information of the target area graphic; and determining a target anti-reflection layer thickness for reducing the connectivity risk of the target area graphic based on a comparison result of the target curve slopes corresponding to each preset anti-reflection layer thickness.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, and in particular to a method for determining the thickness of an anti-reflection layer. Background Art

[0002] During the exposure process of the wafer, in order to eliminate the influence of the reflected light of the photoresist on the exposure and subsequent etching process, an anti-reflection layer needs to be set between the substrate and the photoresist. The anti-reflection layer can reduce the standing wave effect caused by the exposure and improve the exposure contrast, so that the light received inside the photoresist only comes from the exposure light source. Therefore, it is necessary to determine the accurate thickness of the anti-reflection layer to improve the degree of elimination of the standing wave effect.

[0003] In the prior art, reflectivity simulation software (such as ilitho) is used to simulate the reflectivity of a specific film layer combination under different anti-reflection layer thicknesses. The specific film layer combination includes at least one substrate, an anti-reflection layer located on the top substrate, and a photoresist located on the anti-reflection layer. In the actual simulation process, only the arrangement of each layer of the substrate is considered, and the pattern to be exposed on the substrate is not considered, resulting in the optimal anti-reflection layer thickness obtained by simulation not being suitable for the actual pattern to be exposed, which is easy to affect the exposure effect. Summary of the invention

[0004] In view of this, the purpose of the present application is to at least provide a method for determining the thickness of an anti-reflection layer, by determining a target area graphic that has a connectivity risk on the overall exposure graphic that needs to be exposed on a wafer, and obtaining a preset window graphic corresponding to the target area graphic in multiple basic window graphics and a preset anti-reflection layer thickness corresponding to the target area graphic respectively, inputting the graphic file of the target area graphic into an optical proximity correction model to perform multiple optical simulations, and adjusting the anti-reflection layer thickness in the model according to the preset anti-reflection layer thickness during each simulation, thereby obtaining a simulation curve of the target area graphic corresponding to each preset anti-reflection layer thickness, and determining the anti-reflection layer thickness that reduces the connectivity risk of the target area graphic by comparing the light intensity slopes of the connectivity risk position of the target area graphic in the simulation curves corresponding to different preset anti-reflection layer thicknesses, thereby solving the technical problem in the prior art that the optimal anti-reflection layer thickness obtained by performing reflectivity simulation without considering the exposure graphic is inaccurate, and achieving the technical effect of increasing the simulation accuracy of the optimal anti-reflection layer thickness and improving the exposure efficiency.

[0005] This application mainly includes the following aspects:

[0006] In a first aspect, an embodiment of the present application provides a method for determining the thickness of an anti-reflection layer, the method comprising: obtaining a graphic file of a target area graphic corresponding to a wafer to be exposed, the target area graphic being used to indicate an area graphic having a risk of connectivity on an overall exposure graphic used when exposing the wafer to be exposed, the graphic file comprising coordinates of the graphic in a target direction having a risk of connectivity; obtaining at least one preset window graphic and a preset anti-reflection layer thickness respectively corresponding to the target area graphic, the preset window graphic being a basic window graphic corresponding to the target area graphic selected from a plurality of basic window graphics in a wafer exposure process; and combining the graphic file and the preset window graphic. Suppose the thickness of the anti-reflection layer is input into the optical proximity correction model to perform optical simulation, and obtain a simulation curve of the light intensity corresponding to each preset anti-reflection layer thickness changing with the coordinates, wherein the light intensity is used to indicate the sum of the preset incident light intensity and the simulated reflected light intensity of the wafer exposure process; in the simulation curve corresponding to each preset anti-reflection layer thickness, determine the target curve slope corresponding to the preset position information of the target area graphic, and the preset position information corresponds to the position where there is a connectivity risk in the target area graphic; based on the comparison result of the target curve slope corresponding to each preset anti-reflection layer thickness, determine the target anti-reflection layer thickness for reducing the connectivity risk of the target area graphic.

[0007] Optionally, the preset anti-reflection layer thicknesses respectively corresponding to at least one preset window graphic and the target area graphic are obtained in the following manner: constructing optical simulation sub-models respectively corresponding to a plurality of anti-reflection layer thicknesses in the optical proximity correction model; taking the at least one preset window graphic and the target area graphic as a plurality of candidate graphics; inputting the plurality of candidate graphics into the optical simulation sub-models respectively corresponding to a plurality of anti-reflection layer thicknesses, and obtaining a data file covering the light intensity corresponding to each candidate graphic under a plurality of anti-reflection layer thicknesses; and determining the preset anti-reflection layer thicknesses respectively corresponding to at least one preset window graphic and the target area graphic in the data file.

[0008] Optionally, the preset anti-reflection layer thicknesses respectively corresponding to at least one preset window graphic and the target area graphic are determined in the data file in the following manner: a light intensity curve of each candidate graphic as the light intensity varies with the anti-reflection layer thickness is obtained through the data file; and based on the light intensity curves respectively corresponding to the at least one preset window graphic and the target area graphic, the preset anti-reflection layer thicknesses respectively corresponding to the at least one preset window graphic and the target area graphic are determined.

[0009] Optionally, the preset anti-reflection layer thickness includes: a preset minimum value of the light intensity curve, or an anti-reflection layer thickness selected according to the light intensity in the light intensity curve based on wafer exposure process requirements.

[0010] Optionally, multiple optical simulation sub-models corresponding to the thickness of the anti-reflection layer are constructed in the optical proximity correction model in the following manner: light intensity thresholds for the multiple optical simulation sub-models are obtained, the light intensity threshold is the light intensity threshold corresponding to the exposure of the preset basic window pattern to obtain the minimum design rule size and exposed to the target size, and the light intensity threshold is used to indicate the light intensity corresponding to the minimum simulated reflection light intensity; multiple optical simulation sub-models are constructed according to the preset exposure light source wavelength of the wafer exposure process, the preset numerical aperture, the light intensity threshold and the film layer information of the wafer to be exposed, wherein the film layer information includes: the thicknesses, preset refractive index and preset extinction coefficient corresponding to the anti-reflection layer, the photoresist and at least one layer of the substrate, respectively, and the anti-reflection layer thicknesses corresponding to the multiple optical simulation sub-models are different.

[0011] Optionally, when the target area graphic is symmetrical about the midline of the target direction, the coordinates corresponding to the preset position information are located on either side of the middle position of the simulation curve.

[0012] Optionally, a target anti-reflection layer thickness for reducing the connectivity risk of the target area graphics is determined in the following manner: by comparing the target curve slopes corresponding to each preset anti-reflection layer thickness, the preset anti-reflection layer thickness corresponding to the maximum target curve slope is used as the target anti-reflection layer thickness; or, when the target curve slopes corresponding to each preset anti-reflection layer thickness belong to the preset curve slope range, the target anti-reflection layer thickness is determined in a target anti-reflection layer thickness range based on the wafer exposure process requirements, wherein the limit values ​​of the target anti-reflection layer thickness range are the maximum and minimum values ​​of multiple preset anti-reflection layer thicknesses.

[0013] Optionally, the method further includes: obtaining a plurality of update area graphics by adding compensation graphics of different sizes outwardly from a target position of the target area graphic, wherein the target position is used to affect an edge spacing of the target area graphic in the target direction after being processed by an optical proximity correction model, and the edge spacing is used to indicate a spacing at which there is a risk of connectivity after exposure; inputting a graphic file of each update area graphic into the optical proximity correction model for exposure prediction to obtain a simulated edge spacing after exposure corresponding to each update area graphic; and using the update area graphic with the largest simulated edge spacing as an actual area graphic used for actually exposing the target area graphic.

[0014] Optionally, the method further includes: replacing the target area pattern on the overall exposure pattern with the actual area pattern to obtain an updated overall exposure pattern for exposing the wafer to be exposed; and exposing the wafer to be exposed through a mask covering the updated overall exposure pattern.

[0015] Optionally, the plurality of basic window patterns include dense patterns, prohibited period patterns, isolated patterns, end-to-end patterns and end-to-line patterns.

[0016] An embodiment of the present application provides a method for determining the thickness of an anti-reflection layer, the method comprising: obtaining a graphic file of a target area graphic corresponding to a wafer to be exposed, the target area graphic being used to indicate an area graphic having a risk of connectivity on an overall exposure graphic used when exposing the wafer to be exposed, the graphic file comprising coordinates of the graphic in a target direction having a risk of connectivity; obtaining at least one preset window graphic and a preset anti-reflection layer thickness respectively corresponding to the target area graphic, the preset window graphic being a basic window graphic corresponding to the target area graphic selected from a plurality of basic window graphics in a wafer exposure process; and combining the graphic file and the preset anti-reflection layer. The thickness of the reflective layer is input into the optical proximity correction model to perform optical simulation, and a simulation curve of the light intensity corresponding to each preset anti-reflective layer thickness changing with the coordinates is obtained, wherein the light intensity is used to indicate the sum of the preset incident light intensity and the simulated reflected light intensity of the wafer exposure process; in the simulation curve corresponding to each preset anti-reflective layer thickness, the target curve slope corresponding to the preset position information of the target area graphic is determined, and the preset position information corresponds to the position where there is a connectivity risk in the target area graphic; based on the comparison result of the target curve slope corresponding to each preset anti-reflective layer thickness, the target anti-reflective layer thickness for reducing the connectivity risk of the target area graphic is determined. The present application determines a target area graphic that has a connectivity risk on an overall exposure graphic that needs to be exposed on a wafer, obtains a preset window graphic corresponding to the target area graphic in multiple basic window graphics and a preset anti-reflection layer thickness corresponding to the target area graphic, inputs the graphic file of the target area graphic into an optical proximity correction model to perform multiple optical simulations, and adjusts the anti-reflection layer thickness in the model according to the preset anti-reflection layer thickness during each simulation, thereby obtaining a simulation curve of the target area graphic corresponding to each preset anti-reflection layer thickness, and determines the anti-reflection layer thickness that reduces the connectivity risk of the target area graphic by comparing the light intensity slopes of the connectivity risk position of the target area graphic in the simulation curves corresponding to different preset anti-reflection layer thicknesses, thereby solving the technical problem in the prior art that the optimal anti-reflection layer thickness obtained by performing reflectivity simulation without considering the exposure graphic is inaccurate, and achieves the technical effect of increasing the simulation accuracy of the optimal anti-reflection layer thickness and improving the exposure efficiency.

[0017] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 A schematic diagram of an anti-reflection layer provided in an embodiment of the present application is shown.

[0020] Figure 2 A flow chart of a method for determining the thickness of an anti-reflection layer provided in an embodiment of the present application is shown.

[0021] Figure 3 A schematic diagram of a target area graphic provided in an embodiment of the present application is shown.

[0022] Figure 4 A schematic diagram of multiple basic window graphics provided by an embodiment of the present application is shown.

[0023] Figure 5 A schematic diagram showing a simulation curve corresponding to a preset basic window pattern provided in an embodiment of the present application under an anti-reflection layer thickness.

[0024] Figure 6 A schematic diagram showing a relationship curve between the thickness of the anti-reflection layer and the light intensity corresponding to the dense pattern provided in an embodiment of the present application.

[0025] Figure 7 A schematic diagram showing a relationship curve between the thickness of the anti-reflection layer and the light intensity corresponding to the forbidden periodic pattern provided in an embodiment of the present application.

[0026] Figure 8 A schematic diagram showing a relationship curve between the thickness of the anti-reflection layer and the light intensity corresponding to the isolated lines provided in the embodiment of the present application.

[0027] Fig. 9 A schematic diagram showing a relationship curve between the thickness of the anti-reflection layer and the light intensity corresponding to the isolated gap provided in an embodiment of the present application is shown.

[0028] Fig.10 A schematic diagram of a light intensity curve corresponding to an end-to-end point graphic provided in an embodiment of the present application is shown.

[0029] Fig.11 A schematic diagram showing a simulation curve corresponding to a target area pattern provided in an embodiment of the present application under a preset anti-reflection layer thickness of a dense pattern.

[0030] Fig.12A schematic diagram showing a simulation curve corresponding to a target area pattern provided in an embodiment of the present application under a preset anti-reflection layer thickness of an end-to-end pattern.

[0031] Fig.13 A schematic diagram of the simulated edge spacing provided by an embodiment of the present application is shown. DETAILED DESCRIPTION

[0032] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of explanation and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn in real proportion. The flowchart used in this application shows the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowchart can be implemented out of sequence, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art, under the guidance of the content of the present application, can add one or more other operations to the flowchart, or remove one or more operations from the flowchart.

[0033] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0034] In the prior art, during the exposure process of the wafer, an anti-reflection layer needs to be provided between the substrate and the photoresist to reduce the standing wave effect caused by the exposure and improve the exposure contrast. Figure 1 , Figure 1 This is a schematic diagram of the anti-reflection layer provided in the embodiment of the present application. Figure 1 As shown, the anti-reflection layer 102 is disposed between the substrate 101 and the photoresist 103. 1 The photoresist is irradiated, and the upper surface of the photoresist reflects the reflected light A 2 , the incident light generates refracted light B in the photoresist 1The contact part between the bottom of the photoresist and the anti-reflection layer reflects the reflected light for the refracted light in the photoresist, the refracted light of the photoresist generates refracted light in the anti-reflection layer, and the contact part between the bottom of the anti-reflection layer and the substrate reflects the reflected light for the refracted light of the anti-reflection layer. By changing the thickness of the anti-reflection layer, the reflected light generated by the anti-reflection layer is controlled to be parallel to the reflected light generated by the photoresist and the phase difference between the two is about 180 degrees, so as to cancel the reflected light in the photoresist, so that the light received inside the photoresist only comes from the incident light. Therefore, by adding the anti-reflection layer 102 to absorb the reflected light generated by the photoresist, it is necessary to determine the optimal thickness of the anti-reflection layer to generate the reflected light.

[0035] At present, reflectivity simulation software (such as ilitho) is used to simulate the reflectivity of a specific film layer combination under different anti-reflection layer thicknesses. The specific film layer combination includes at least one substrate, an anti-reflection layer located on the top substrate, and a photoresist located on the anti-reflection layer. In the actual simulation process, only the arrangement of each layer of the substrate is considered, and the substrate is a uniform substrate, without considering the pattern that needs to be exposed on the substrate, resulting in the optimal anti-reflection layer thickness obtained by simulation not being suitable for the actual exposed pattern, which is easy to affect the exposure effect.

[0036] Based on this, an embodiment of the present application provides a method for determining the thickness of an anti-reflection layer, by determining a target area graphic having a connection risk on an overall exposure graphic that needs to be exposed on a wafer, and obtaining a preset window graphic corresponding to the target area graphic and a preset anti-reflection layer thickness corresponding to the target area graphic in multiple basic window graphics, inputting a graphic file of the target area graphic into an optical proximity correction model to perform multiple optical simulations, and adjusting the anti-reflection layer thickness in the model according to the preset anti-reflection layer thickness in each simulation, thereby obtaining a simulation curve of the target area graphic corresponding to each preset anti-reflection layer thickness, and determining the anti-reflection layer thickness that reduces the connection risk of the target area graphic by comparing the light intensity slopes of the connection risk position of the target area graphic in the simulation curves corresponding to different preset anti-reflection layer thicknesses, thereby solving the technical problem of inaccurate optimal anti-reflection layer thickness obtained by performing reflectivity simulation without considering the exposure graphic in the prior art, and achieving the technical effect of increasing the simulation accuracy of the optimal anti-reflection layer thickness and improving the exposure efficiency, as described in detail as follows:

[0037] See also Figure 2 , Figure 2 This is a flow chart of a method for determining the thickness of an anti-reflection layer provided in an embodiment of the present application. Figure 2 As shown, the method for determining the thickness of the anti-reflection layer provided in the embodiment of the present application comprises the following steps:

[0038] S101: Acquire a graphic file of a target area graphic corresponding to a wafer to be exposed.

[0039] The target area graphic is used to indicate an area graphic having a connection risk on the overall exposure graphic used when exposing the wafer to be exposed, and the graphic file includes the coordinates of the graphic in the target direction having a connection risk.

[0040] The overall exposure pattern refers to the overall pattern pre-designed for the exposure process of the wafer to be exposed. The target area pattern is the process weak pattern for the exposure process of the wafer to be exposed, that is, the patterns corresponding to the target area pattern before and after exposure will be greatly different, and the interval area in the target area pattern may become a connected area after exposure, resulting in failure to realize exposure according to the pre-designed pattern, which affects the subsequent semiconductor manufacturing process.

[0041] The graphic file of the target area graphic includes the target area graphic and its coordinates in the target direction where there is a connectivity risk. The target direction where there is a connectivity risk may be any direction of the target area graphic, and thus the target direction may also be any direction. Exemplarily, the target direction may be a horizontal direction or a vertical direction, and the coordinates in the target direction may be coordinates in the horizontal direction or the vertical direction.

[0042] For example, see Figure 3 , Figure 3 This is a schematic diagram of a target area graphic provided in an embodiment of the present application. Figure 3 As shown, the target area graphic has a process weakness L in the horizontal direction, and L should be disconnected after the exposure process. However, during the exposure process, L may be connected to affect the completion of the graphic exposure, and there is no area with a risk of connection in the vertical direction. Furthermore, the horizontal direction is the target direction, so the graphic file of the target area graphic includes the coordinates in the horizontal direction.

[0043] S102: Obtaining preset anti-reflection layer thicknesses corresponding to at least one preset window pattern and the target area pattern respectively.

[0044] The preset window pattern is a basic window pattern corresponding to the target area pattern selected from a plurality of basic window patterns in a wafer exposure process.

[0045] Among them, the multiple basic window graphics include dense graphics, prohibited periodic graphics, isolated graphics, end-to-end graphics and end-to-line graphics. Among them, dense graphics are defined as lines and line spacing ratios of 1:1 to 1:1.3, prohibited periodic graphics are defined as lines and line spacing ratios of 1:1.5 to 1:3, and isolated graphics are defined as line spacing greater than 1um (i.e. isolated lines) or space spacing greater than 1um (i.e. isolated gaps). End-to-end graphics can be understood as gaps between the endpoints of adjacent line segments, and end-to-line graphics can be understood as gaps between the endpoints of line segments and the lines.

[0046] For example, see Figure 4 , Figure 4 Schematic diagram of multiple basic window graphics provided by the embodiment of the present application. Figure 4 As shown, 401 is a dense pattern, 402 is a prohibited periodic pattern, 403 is an isolated line in an isolated pattern, 404 is an isolated gap in an isolated pattern, 405 is an end-to-end point pattern, and 406 is an end-to-line pattern.

[0047] The preset anti-reflection layer thickness corresponding to at least one preset window pattern and the target area pattern is the optimal anti-reflection layer thickness required for exposure according to the pattern. That is to say, one preset window pattern corresponds to one preset anti-reflection layer thickness, different preset window patterns may correspond to different preset anti-reflection layer thicknesses, the target area pattern also has its corresponding preset anti-reflection layer thickness, and the preset anti-reflection layer thickness corresponding to the target area pattern may also be different from the preset anti-reflection layer thickness corresponding to the preset window pattern.

[0048] Specifically, the target area graphic can be understood as being obtained by combining, splicing or deforming the basic window graphics in the actual exposure graphic design. Furthermore, when determining the preset window graphic corresponding to the target area graphic, a basic window graphic that is similar to the area where there is a risk of connectivity with the target area graphic in the target direction can be determined from multiple basic window graphics as the preset window graphic.

[0049] Exemplarily, a basic window graphic similar to the target area graphic is selected from multiple basic window graphics in the following manner: by manual pre-selection, or by determining the similarity between each basic window graphic and the target area graphic in the target direction in terms of the area at risk of being connected by image comparison, and the basic window graphic with the highest similarity can be selected as the preset window graphic. This application does not set any limitation on this.

[0050] For example, Figure 3As shown, the process weak point L of the target area pattern is approximately equal to the gap between two line segments in the dense pattern and can also be approximately equal to the gap between the endpoints of two line segments in the end-to-end point pattern.

[0051] Furthermore, it is possible to determine by the naked eye or by image comparison which basic window graphics cover the process weaknesses of the target area graphics, and use the basic window graphics covering the process weaknesses of the target area graphics as the basic window graphics that are similar to the target area graphics, i.e., as the preset window graphics.

[0052] Specifically, the preset anti-reflection layer thicknesses respectively corresponding to at least one preset window graphic and the target area graphic are obtained in the following manner: constructing a plurality of optical simulation sub-models respectively corresponding to the anti-reflection layer thicknesses in the optical proximity correction model; taking the at least one preset window graphic and the target area graphic as a plurality of candidate graphics; inputting the plurality of candidate graphics into the optical simulation sub-models respectively corresponding to the plurality of anti-reflection layer thicknesses, and obtaining a data file covering the light intensity corresponding to each candidate graphic under the plurality of anti-reflection layer thicknesses; and determining the preset anti-reflection layer thicknesses respectively corresponding to at least one preset window graphic and the target area graphic in the data file.

[0053] Among them, multiple optical simulation sub-models corresponding to the thickness of the anti-reflection layer are constructed in the optical proximity correction model in the following manner: light intensity thresholds for multiple optical simulation sub-models are obtained, and the light intensity threshold is the light intensity threshold corresponding to the exposure of the preset basic window pattern to obtain the minimum design rule size and exposed to the target size, and the light intensity threshold is used to indicate the light intensity corresponding to the minimum simulated reflection light intensity; multiple optical simulation sub-models are constructed according to the preset exposure light source wavelength of the wafer exposure process, the preset numerical aperture, the light intensity threshold and the film layer information of the wafer to be exposed, wherein the film layer information includes: the thicknesses, preset refractive index and preset extinction coefficient corresponding to the anti-reflection layer, the photoresist and at least one layer of the substrate, respectively, and the anti-reflection layer thicknesses corresponding to the multiple optical simulation sub-models are different.

[0054] The light intensity thresholds for multiple optical simulation sub-models are obtained in the following manner: a preset basic window pattern is subjected to an exposure simulation at a randomly set anti-reflection layer thickness to obtain a simulation curve, and the simulation curve is used to determine the corresponding light intensity threshold when the minimum design rule size of the preset basic window pattern is exposed to the target size.

[0055] For example, see Figure 5 , Figure 5 This is a schematic diagram of a simulation curve corresponding to a preset basic window pattern under an anti-reflection layer thickness provided in an embodiment of the present application. Figure 5 As shown, the horizontal axis is used to indicate any dense graph (such as Figure 3 ) is the coordinate in the target direction, the target direction is horizontal, and the dense pattern is symmetrical about the midline of the target direction. The ordinate is used to indicate the light intensity. The line width of the minimum design size is 0.12um (micrometer), and the target size is 0.122um. The red line is used to indicate that the minimum design rule size is exposed to the target size. The corresponding light intensity simulation threshold is 0.095, the image logarithmic slope ILS is 22.267, and the normalized image logarithmic slope NILS is 2.717. Furthermore, 0.095 is used as the light intensity threshold for the subsequent model building.

[0056] The light intensity threshold is used to determine the minimum light intensity for exposing a graphic. That is, exposure can be achieved as long as the light intensity is greater than or equal to the light intensity threshold. If the light intensity is less than the light intensity threshold, the graphic cannot be exposed.

[0057] Among them, the minimum design dimension (CD) can be understood as the line width of the basic window graphics. The minimum design dimensions of different basic window graphics can be different, and the target sizes corresponding to the minimum design dimensions of different basic window graphics can also be different. In other words, a dense graphic corresponds to a target size. When a dense graphic is selected for optical simulation, the light intensity threshold determined when the minimum design dimension corresponding to the dense graphic is simulated to the target size is used as the light intensity threshold set for the subsequent construction of multiple optical simulation sub-models corresponding to the thickness of the anti-reflection layer.

[0058] That is to say, after knowing the light intensity threshold, multiple optical simulation sub-models are constructed by changing different anti-reflection layer thicknesses, and one anti-reflection layer thickness corresponds to one optical simulation sub-model. For each optical simulation sub-model, according to the preset exposure light source wavelength, preset numerical aperture, light intensity threshold of the wafer exposure process, and the thickness, preset refractive index and preset extinction coefficient of the photoresist, at least one layer of substrate and anti-reflection layer respectively covered in the film layer information corresponding to the optical simulation sub-model. In other words, only the thickness of the anti-reflection layer is different between the multiple optical simulation sub-models, and the others are the same. The anti-reflection layer is located below the photoresist layer, and at least one layer of substrate is stacked below the anti-reflection layer, so as to facilitate the construction of optical simulation sub-models corresponding to different anti-reflection layer thicknesses.

[0059] In other words, the optical simulation sub-model is a white box model, which solves the Hopkins optical equation by inputting parameters such as exposure light source wavelength, numerical aperture, lighting conditions, film thickness, and corresponding refractive index and extinction coefficient, so that the light intensity of each pattern under a specific substrate combination can be calculated. The optical model is considered to be a reasonable model if it contributes more than 70% of the entire OPC model, that is, the size of the pattern after exposure predicted by the optical simulation sub-model accounts for 70% of the size of the initial input image, and the initial light intensity distribution can be accurately simulated when the optical simulation sub-model is used to simulate the exposure of the input image.

[0060] Furthermore, after constructing optical simulation sub-models corresponding to multiple anti-reflection layer thicknesses, at least one preset window graphic and a target area graphic are used as multiple candidate graphics, and the graphic files corresponding to the multiple candidate graphics are input into the optical simulation sub-models corresponding to the multiple anti-reflection layer thicknesses to obtain a data file. The data file includes the light intensities obtained by optically simulating all the candidate graphics under the optical simulation sub-models corresponding to different anti-reflection layer thicknesses.

[0061] The size of each candidate graphic input to the optical proximity correction model should be about 4um×4um (micrometers), ensuring that the point where the light intensity is to be calculated is not affected by the optical size and ensuring the accuracy and speed of the calculation. For each candidate graphic, the graphic file of the candidate graphic includes the coordinates of the target direction corresponding to the candidate graphic. The graphic is generally symmetrical with the midline of the target direction, that is, each candidate graphic is symmetrical with the midline of its corresponding target direction.

[0062] Specifically, the preset anti-reflection layer thicknesses respectively corresponding to at least one preset window graphic and the target area graphic are determined in the data file in the following manner: a light intensity curve of each candidate graphic as the light intensity varies with the anti-reflection layer thickness is obtained through the data file; and the preset anti-reflection layer thicknesses respectively corresponding to at least one preset window graphic and the target area graphic are determined based on the light intensity curves respectively corresponding to the at least one preset window graphic and the target area graphic.

[0063] Among them, the preset anti-reflection layer thickness of each basic window graphic is determined in the following way: different anti-reflection layer thicknesses are used as the horizontal coordinate, and the light intensity corresponding to the basic window graphic under different anti-reflection layer thicknesses is used as the vertical coordinate, and the light intensity curve of the anti-reflection layer thickness and light intensity corresponding to the basic window graphic is drawn, and the anti-reflection layer thickness corresponding to the basic window graphic is determined by the trend of the light intensity curve.

[0064] That is to say, the data file can be used to analyze the light intensity corresponding to each candidate graphic under different anti-reflection layer thicknesses, and then, for each candidate graphic, a light intensity curve of the candidate graphic is constructed, where the horizontal axis of the light intensity curve is the anti-reflection layer thickness, and the vertical axis is the light intensity. In this way, the light intensity curve of the candidate graphic under different anti-reflection layer thicknesses is generated through the light intensity corresponding to the candidate graphic in the data file.

[0065] Among them, the light intensity is used to indicate the sum of the preset incident light intensity and the simulated reflected light intensity of the wafer exposure process. The preset incident light intensity is generally considered to be fixed. Therefore, the greater the light intensity, the greater the simulated reflected light intensity. The greater the simulated reflected light intensity, the less the reflected light of the photoresist absorbed by the anti-reflection layer. Therefore, in order to reduce the simulated reflected light intensity, the thickness of the anti-reflection layer corresponding to the smaller light intensity value is generally selected.

[0066] The preset anti-reflection layer thickness includes: a preset minimum value of the light intensity curve, or an anti-reflection layer thickness selected according to the light intensity in the light intensity curve based on wafer exposure process requirements.

[0067] That is, for each basic window pattern, a preset minimum value representing the preset anti-reflection layer thickness is found on the light intensity curve of the anti-reflection layer thickness and light intensity corresponding to the basic window pattern, and the anti-reflection layer thickness corresponding to the preset minimum value is used as the preset anti-reflection layer thickness of the basic window pattern. Alternatively, the value of the horizontal coordinate corresponding to the light intensity required by the wafer exposure process requirements is used as the preset anti-reflection layer thickness of the basic window pattern on the light intensity curve.

[0068] Generally, the preset minimum value is the second minimum value. Exemplarily, the graphic files of all basic window graphics can be input into the optical simulation sub-models corresponding to the thickness of multiple anti-reflection layers in advance, and the light intensity curve corresponding to each basic window graphic can be obtained by using the data file of the light intensity corresponding to each basic window graphic under different anti-reflection layer thicknesses output by the model, so as to obtain the preset anti-reflection layer thickness of each basic window graphic, and then, when the graphic files of different target area graphics are input later, the preset anti-reflection layer thickness of the basic window graphics similar to the target area graphics can be directly obtained, without multiple simulations through the optical simulation sub-model, reducing the operation steps and increasing efficiency.

[0069] For example, see Figures 6 to 10 , Figure 6 A schematic diagram of a light intensity curve corresponding to a dense pattern provided in an embodiment of the present application, Figure 7 A schematic diagram of a light intensity curve corresponding to a prohibited periodic pattern provided in an embodiment of the present application, Figure 8 Schematic diagram of light intensity curves corresponding to isolated lines provided in the embodiment of the present application, Fig. 9A schematic diagram of a light intensity curve corresponding to an isolated gap provided in an embodiment of the present application, Fig.10 This is a schematic diagram of the light intensity curve corresponding to the end-to-end graph provided in the embodiment of the present application. Figures 6 to 10 As shown, the thickness of the anti-reflection layer ranges from 0 to 200nm. After the thickness of the anti-reflection layer increases to a certain extent, the light intensity gradually tends to be constant, and, as the thickness of the anti-reflection layer increases, the first minimum value of the light intensity appears for the first time and the second minimum value of the light intensity appears for the second time. The light intensity corresponding to the first minimum value is generally the minimum value, but because the slope of the point close to the first minimum value is large, the thickness of the anti-reflection layer corresponding to the first minimum value fluctuates slightly, which will cause the light intensity to be unstable. Therefore, the second minimum value is generally selected as the preset minimum value. When the thickness is greater than 150nm, the light intensity curve is flat, indicating that when the thickness of the anti-reflection layer is relatively thick, the effect on the light intensity can be ignored. Since the thickness of the anti-reflection layer is calculated as a conventional film quality in the optical model calculation, the calculation method of the preset minimum value and the above phenomenon are also applicable to materials such as insulating anti-reflection layer (DARC) and silicon dioxide.

[0070] Exemplarily, Table 1 shows the various minimum values ​​of the light intensity curve of the relationship between the thickness of the anti-reflection layer and the light intensity corresponding to the dense pattern obtained by simulating the ilitho software and the optical proximity correction model (opc) respectively.

[0071] Table 1:

[0072]

[0073] The third minimum refers to the third minimum light intensity value that appears as the thickness increases. That is to say, the light intensity curve simulated by the optical proximity correction model is similar to the light intensity curve simulated by ilitho in the prior art, that is, the optical proximity correction model can obtain a light intensity curve that reflects the relationship between the thickness of the anti-reflection layer and the light intensity through optical simulation.

[0074] Exemplarily, the optical simulation involved in the embodiments of the present application is mainly used in terminal devices, which mainly refer to software operation interfaces for providing optical proximity correction models. Terminal devices may include but are not limited to any of the following devices: smart phones, tablet computers, portable computers, desktop computers, game consoles, personal digital assistants (PDAs), e-book readers, MP4 (Moving Picture Experts Group Audio Layer IV) players, etc. The terminal device has an application program that supports the optical proximity correction model installed and running, such as Mentor software.

[0075] That is, optical simulation is performed by installing Mentor software on the terminal device and constructing an optical simulation sub-model through the optical proximity correction model of the Mentor software.

[0076] S103: Inputting the graphic file and the preset anti-reflection layer thickness into an optical proximity correction model to perform optical simulation, and obtaining a simulation curve of light intensity corresponding to each preset anti-reflection layer thickness changing with coordinates.

[0077] That is to say, the graphic file of the target area graphic and each preset anti-reflection layer thickness are input into the optical proximity correction model for optical simulation, and a simulation curve reflecting the different coordinates of the target area graphic in the target direction and its corresponding light intensity under each preset anti-reflection layer thickness is obtained.

[0078] For example, in the target area the graphic is Figure 3 When the graphics shown are shown, the preset window graphics corresponding to the target area graphics are dense graphics and end-to-end graphics. Fig.11 and Fig.12 , Fig.11 A schematic diagram of a simulation curve corresponding to a target area pattern provided in an embodiment of the present application under a preset anti-reflection layer thickness of a dense pattern, Fig.12 This is a schematic diagram of a simulation curve corresponding to the target area pattern provided in the embodiment of the present application under its own preset anti-reflection layer thickness. Fig.11 and Fig.12 As shown, the graphic file of the target area graphic and the preset anti-reflection layer thickness of the dense graphic are input into the optical proximity correction model for optical simulation to obtain Fig.11 The coordinate file of the target area graphics and the preset anti-reflection layer thickness are input into the optical proximity correction model for optical simulation. Fig.12 For the simulation curve, the target area graph is symmetrical about the midline in the horizontal direction, and thus, the obtained simulation curve is also symmetrical about the vertical line of the middle coordinate of the horizontal coordinate.

[0079] S104: In the simulation curve corresponding to each preset anti-reflection layer thickness, determine the target curve slope corresponding to the preset position information of the target area graphic.

[0080] The preset position information corresponds to a position in the target area graph where there is a risk of connectivity. When the target area graph is symmetrical about the midline of the target direction, the coordinates corresponding to the preset position information are located on either side of the middle position of the simulation curve.

[0081] That is to say, the process weaknesses that are prone to connection risks are identified in the target area graph. Figure 3As shown, the process weakness L is taken as the distance between the endpoints of the two line segments, and since the target area graphic is symmetrical with the midline of the target direction, the position of any one of the two endpoints is taken as the position where there is a risk of connectivity, and the coordinates of the endpoint are taken as the preset position information, that is, the coordinates of any one of the two ends of the process weakness L in the target direction are taken as the preset position information.

[0082] For example, Fig.11 As shown, in the simulation curve obtained by optically simulating the target area pattern under the preset anti-reflection layer thickness of the dense pattern, the slope corresponding to the coordinate of an end point of the process weak point of the target area pattern on the simulation curve is used as the slope of the target curve. Fig.12 As shown, in the simulation curve obtained by optically simulating the target region pattern under the corresponding preset anti-reflection layer thickness, the slope corresponding to the coordinate of one end point of the process weakness of the target region pattern on the simulation curve is used as the slope of the target curve. Fig.11 and Fig.12 The selected preset location information is a location, that is, Fig.11 and Fig.12 The abscissas of the determined target curve slopes are the same.

[0083] S105: Determine a target anti-reflection layer thickness for reducing the connectivity risk of the target region pattern according to a comparison result of the target curve slope corresponding to each preset anti-reflection layer thickness.

[0084] The target anti-reflection layer thickness for reducing the connectivity risk of the target area graphics is determined in the following manner: by comparing the target curve slopes corresponding to each preset anti-reflection layer thickness, the preset anti-reflection layer thickness corresponding to the maximum target curve slope is used as the target anti-reflection layer thickness; or, when the target curve slopes corresponding to each preset anti-reflection layer thickness belong to the preset curve slope range, the target anti-reflection layer thickness is determined in the target anti-reflection layer thickness range based on the wafer exposure process requirements, wherein the limit values ​​of the target anti-reflection layer thickness range are the maximum and minimum values ​​of multiple preset anti-reflection layer thicknesses.

[0085] Among them, selecting the largest target curve slope represents the fastest drop in light intensity, the image edge is correspondingly sharper, and the exposure effect is better. Furthermore, the preset anti-reflection layer thickness where the simulation curve corresponding to the largest target curve slope is located can be selected as the target anti-reflection layer thickness for actual exposure.

[0086] For example, Fig.11 The target curve slope of the preset position information is -1.036. Fig.12The target curve slope Slope of the preset position information is -1.111. After taking the absolute value of the target curve slope for comparison, that is, 1.111 is greater than 1.036. Therefore, the effect of optical simulation under the preset anti-reflection layer thickness of the target area graphics is better than that of optical simulation under the preset anti-reflection layer thickness of the dense graphics.

[0087] That is to say, the exposure pattern obtained by performing exposure when the slope of the curve is the largest is most similar to the target area pattern originally designed, that is, the deformation caused by performing exposure when the slope of the curve is the largest is the smallest. Furthermore, the preset anti-reflection layer thickness of the preset window pattern corresponding to the maximum curve slope is used as the target anti-reflection layer thickness selected that is most suitable for exposure. In this way, the target area pattern is considered to select the most suitable multiple preset anti-reflection layer thicknesses, and then the target anti-reflection layer thickness with the smallest exposure effect is selected from the multiple preset anti-reflection layer thicknesses through optical simulation, thereby increasing the accuracy of the selected anti-reflection layer thickness and reducing the exposure deformation caused by the reflection of the photoresist, thereby improving the exposure efficiency.

[0088] Alternatively, the preset curve slope range is determined according to the target curve slope corresponding to each preset anti-reflection layer thickness. The preset curve slope range refers to taking the maximum target curve slope as the upper limit value and taking the product of the maximum target curve slope multiplied by the preset probability as the lower limit value. The preset probability can be set to 90%. Furthermore, when the target curve slope corresponding to each preset anti-reflection layer thickness belongs to the preset curve slope range, it is considered that the difference between the target curve slopes corresponding to each preset anti-reflection layer thickness is small, and the target anti-reflection layer thickness can be determined in the target anti-reflection layer thickness range considering the actual wafer exposure process requirements; when the target curve slope corresponding to any preset anti-reflection layer thickness does not belong to the preset curve slope range, it is considered that there is a large difference between the target curve slopes corresponding to each preset anti-reflection layer thickness. At this time, the preset anti-reflection layer thickness corresponding to the maximum target curve slope is selected as the target anti-reflection layer thickness.

[0089] Wherein, determining the target anti-reflection layer thickness in the target anti-reflection layer thickness interval based on the wafer exposure process requirement includes: if the wafer exposure process requires a setting range of the anti-reflection layer thickness, then taking an anti-reflection layer thickness in the intersection of the setting range and the target anti-reflection layer thickness interval as the target anti-reflection layer thickness. The upper limit value of the target anti-reflection layer thickness interval is the maximum value of multiple preset anti-reflection layer thicknesses, and the lower limit value of the target anti-reflection layer thickness interval is the minimum value of multiple preset anti-reflection layer thicknesses.

[0090] The method also includes: obtaining a plurality of update area graphics by adding compensation graphics of different sizes outwardly to the target position of the target area graphic, wherein the target position is used to affect the edge spacing of the target area graphic in the target direction after being processed by the optical proximity correction model, and the edge spacing is used to indicate the spacing that has a risk of connectivity after exposure; inputting the graphic file of each update area graphic into the optical proximity correction model for exposure prediction to obtain the simulated edge spacing after exposure corresponding to each update area graphic; and using the update area graphic with the largest simulated edge spacing as the actual area graphic used by the target area graphic for actual exposure.

[0091] That is to say, by adding compensation patterns of different sizes outward from the target position of the target area pattern and then performing exposure prediction through the optical proximity correction model, the simulated edge spacings corresponding to the different simulated compensation patterns are obtained, and thus, the updated area pattern that is a combination of the compensation pattern with the largest simulated edge spacing and the target area pattern is selected as the actual area pattern used for actual exposure.

[0092] For example, see Fig.13 , Fig.13 A schematic diagram of the simulated edge spacing provided in the embodiment of the present application, such as Fig.13 As shown, the process weakness L of the target area pattern with the risk of connectivity is obtained by setting a compensation pattern with end points expanding outwardly at the target positions A and B, that is, the target position of the target area pattern is partially expanded outwardly, and the simulated edge spacing L1 obtained without adding a compensation pattern to the outside of the target positions A and B is 89.5nm (nanometers), and the simulated edge spacing L2 obtained by adding a compensation pattern of a certain size to the outside of the target positions A and B is 96.5nm (nanometers). Since the simulated edge spacing L2 is larger than the simulated edge spacing L1, the updated area pattern obtained after adding a compensation pattern of a certain size outwardly at the target positions A and B is used as the actual area pattern used for actual exposure.

[0093] Exemplarily, a simulated edge spacing can be obtained under a compensation pattern of another size added outwardly from the target positions A and B, and by comparing the corresponding simulated edge spacings under compensation patterns of different sizes, the compensation pattern added outwardly from the target positions A and B corresponding to the maximum simulated edge spacing can be selected to be combined with the target area pattern as the actual area pattern.

[0094] The sizes of the compensation graphics corresponding to the target positions A and B can be the same or different. Since the probability of the target position A having a connection risk in the preset direction is greater than the probability of the target position B having a connection risk in the preset direction, the width of the compensation graphics set outward from the target position A in the preset direction is smaller than the width of the compensation graphics set outward from the target position B in the preset direction, so as to prevent the target position A from having a connection risk in the preset direction after simulation. The preset direction is a direction other than the target direction in the horizontal direction and the vertical direction.

[0095] Exemplarily, the graphic file corresponding to the actual area graphic can also be input into the optical simulation sub-models corresponding to the thickness of multiple anti-reflection layers, so as to obtain the light intensity obtained by optical simulation of the actual area graphic under the optical simulation sub-models corresponding to different anti-reflection layer thicknesses, and then obtain the light intensity curve corresponding to the actual area graphic. Exemplarily, the first minimum value of 23.3 nanometers (nm), the second minimum value of 76.9 nm, and the third minimum value of 135.3 nm are obtained on the light intensity curve corresponding to the actual area graphic. Combined with the light intensity curve corresponding to the target area graphic, the first minimum value of 23.7nm, the second minimum value of 77.4nm, and the third minimum value of 135.5nm are obtained. Since the side expansion design has little effect on the layout size after OPC at the endpoint, it can be seen that the side expansion design does not affect the BARC thickness at the light intensity minimum.

[0096] The method also includes: replacing the target area pattern on the overall exposure pattern with the actual area pattern to obtain an updated overall exposure pattern for exposing the wafer to be exposed; and exposing the wafer to be exposed through a mask covering the updated overall exposure pattern.

[0097] That is to say, the target area pattern on the overall exposure pattern is replaced with the actual area pattern to obtain an updated overall exposure pattern. Thus, the pattern after exposing the wafer to be exposed by updating the mask corresponding to the overall exposure pattern is closer to the overall exposure pattern than the pattern after directly using the mask corresponding to the overall exposure pattern to expose the wafer to be exposed. Therefore, the exposure accuracy is improved.

[0098] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the system and device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. In the several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0099] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0100] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0101] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, and other media that can store program codes.

[0102] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for determining the thickness of an anti-reflection layer, characterized in that: The method comprises: Acquire a graphic file of a target area graphic corresponding to the wafer to be exposed, the target area graphic being used to indicate an area graphic having a connection risk on the overall exposure graphic used when exposing the wafer to be exposed, the graphic file including coordinates of the graphic in a target direction having a connection risk; Obtaining a preset anti-reflection layer thickness corresponding to at least one preset window pattern and the target area pattern, respectively, wherein the preset window pattern is a basic window pattern corresponding to the target area pattern selected from a plurality of basic window patterns in a wafer exposure process; Input the graphic file and the preset anti-reflection layer thickness into an optical proximity correction model to perform optical simulation, and obtain a simulation curve of light intensity corresponding to each preset anti-reflection layer thickness changing with coordinates, wherein the light intensity is used to indicate the sum of the preset incident light intensity and the simulated reflected light intensity of the wafer exposure process; In the simulation curve corresponding to each preset anti-reflection layer thickness, determining the target curve slope corresponding to the preset position information of the target area graph, wherein the preset position information corresponds to the position in the target area graph where there is a risk of connectivity; Determining a target anti-reflection layer thickness for reducing the connectivity risk of the target region pattern according to a comparison result of the target curve slope corresponding to each preset anti-reflection layer thickness; Wherein, the method further comprises: A plurality of updated region graphics are obtained by adding compensation graphics of different sizes outwardly to a target position of the target region graphic, wherein the target position is used to affect the edge spacing of the target region graphic in the target direction after being processed by the optical proximity correction model, and the edge spacing is used to indicate the spacing having a risk of connectivity after exposure; Inputting the graphic file of each updated area graphic into the optical proximity correction model to perform exposure prediction, and obtaining the simulated edge spacing after exposure corresponding to each updated area graphic; The updated region pattern with the largest simulated edge spacing is used as the actual region pattern used for actually exposing the target region pattern.

2. The method according to claim 1, characterized in that Obtaining the preset anti-reflection layer thicknesses corresponding to at least one preset window pattern and the target area pattern respectively in the following manner: Constructing a plurality of optical simulation sub-models corresponding to the thickness of the anti-reflection layer in the optical proximity correction model; taking the at least one preset window graphic and the target area graphic as a plurality of candidate graphics; A plurality of candidate graphics are input into optical simulation sub-models corresponding to a plurality of anti-reflection layer thicknesses, respectively, to obtain a data file covering the light intensity corresponding to each candidate graphic under a plurality of anti-reflection layer thicknesses; and in the data file, at least one preset window graphic and a preset anti-reflection layer thickness corresponding to the target area graphic are determined respectively.

3. The method according to claim 2, characterized in that Determine the preset anti-reflection layer thicknesses respectively corresponding to at least one preset window pattern and the target area pattern in the data file in the following manner: Obtaining, through the data file, a light intensity curve of each candidate pattern as the light intensity varies with the thickness of the anti-reflection layer; According to the light intensity curves respectively corresponding to the at least one preset window pattern and the target area pattern, the preset anti-reflection layer thicknesses respectively corresponding to the at least one preset window pattern and the target area pattern are determined.

4. The method according to claim 3, characterized in that The preset anti-reflection layer thickness includes: a preset minimum value of the light intensity curve, Alternatively, the thickness of the anti-reflection layer is selected according to the light intensity in the light intensity curve based on the wafer exposure process requirements.

5. The method according to claim 2, characterized in that: The optical simulation sub-models corresponding to the thickness of multiple anti-reflection layers are constructed in the optical proximity correction model in the following manner: Obtaining light intensity thresholds for multiple optical simulation sub-models, wherein the light intensity threshold is a light intensity threshold corresponding to the exposure of a preset basic window pattern to obtain a minimum design rule size and exposed to a target size, and the light intensity threshold is used to indicate the light intensity corresponding to the minimum simulated reflected light intensity; A plurality of optical simulation sub-models are constructed according to a preset exposure light source wavelength, a preset numerical aperture, the light intensity threshold and the film layer information of the wafer to be exposed in the wafer exposure process, The film layer information includes: thicknesses, preset refractive indices and preset extinction coefficients corresponding to the anti-reflection layer, the photoresist and at least one substrate layer respectively, and the thicknesses of the anti-reflection layers corresponding to the multiple optical simulation sub-models are different.

6. The method according to claim 1, characterized in that When the target area graph is symmetrical about the midline of the target direction, the coordinates corresponding to the preset position information are located on either side of the middle position of the simulation curve.

7. The method according to claim 1, characterized in that The target anti-reflection layer thickness for reducing the risk of connectivity of the target area pattern is determined by: By comparing the target curve slopes corresponding to each preset anti-reflection layer thickness, the preset anti-reflection layer thickness corresponding to the maximum target curve slope is used as the target anti-reflection layer thickness; or, When the target curve slope corresponding to each preset anti-reflection layer thickness belongs to the preset curve slope range, the target anti-reflection layer thickness is determined in the target anti-reflection layer thickness range based on the wafer exposure process requirements, wherein the limit values ​​of the target anti-reflection layer thickness range are the maximum and minimum values ​​of multiple preset anti-reflection layer thicknesses.

8. The method according to claim 1, characterized in that The method further comprises: Replacing the target area pattern on the overall exposure pattern with the actual area pattern to obtain an updated overall exposure pattern for exposing the wafer to be exposed; The wafer to be exposed is exposed through a mask plate covering the updated overall exposure pattern.

9. The method according to claim 1, characterized in that: The plurality of basic window patterns include a dense pattern, a prohibited period pattern, an isolated pattern, an end-to-end pattern, and an end-to-line pattern.

Images