Optimization method for a negative developing photoresist model

Abstract

The present invention relates to the field of semiconductor technology, and particularly to a method for optimizing a negative-tone developing photoresist model, the method including: obtaining an initial negative-tone developing photoresist model; constructing a distribution function S of acid concentration in the photoresist based on light field distribution according to the light field distribution in the initial negative-tone developing photoresist model and the acid concentration in the photoresist; constructing a concentration distribution function D of a developer based on the distribution function S of acid concentration in the photoresist; constructing a developer concentration diffusion calculation formula R for calculating diffusion results of developers with different concentrations based on the concentration distribution function D of the developer; simulating a development process using the developer concentration diffusion calculation formula R to obtain a pseudo-negative-tone developed photoresist pattern after development; and comparing the pseudo-negative-tone developed photoresist pattern with related data in a preset pattern.

Description

[Technical field]

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for optimizing a negative developing photoresist model. [Background technology]

[0002] Photolithography is the most important manufacturing process in the modern ultra-large scale integrated circuit manufacturing process, which is an important means for transferring the design pattern of the integrated circuit on the mask to the silicon wafer by the photolithography equipment. In the manufacturing process, as the feature size becomes smaller and smaller, the process window available for manufacturing also becomes smaller and smaller, but the entire photolithography process needs to be controlled with high precision, so the requirements for high-precision calculation of photolithography become higher and higher. Accurate calculation of lithography model can theoretically explore the way to increase lithography resolution and process window, and guide the optimization of process parameters.

[0003] In the conventional technical solutions, the relatively advanced photoresist technology all adopts negative development. The photoresist used in negative development has good adhesion ability and stopper function, and has a fast photoexposure speed, but due to deformation and expansion during development, the thermal contraction effect of negative development is stronger than that of positive development. Due to the thermal contraction effect, the distribution of the developer is different from the light field distribution during the development process, which reduces the accuracy of modeling. In addition, for a chip, the size of a single chip can be up to 32mm x 26mm, the minimum pattern line width may be only 10nm, and the layout file of a single photoresist layer can be up to several hundred GB, so the modeling speed is a very important technical indicator. However, the conventional optimization method of the negative development photoresist model is difficult to achieve both accuracy and speed. Summary of the Invention

[0004] The present invention provides a method for optimizing a negative-tone developing photoresist model to solve the problem that it is difficult to achieve both accuracy and speed in the conventional method for optimizing a negative-tone developing photoresist model.

[0005] The means for solving the technical problem of the present invention is to obtaining an initial negative tone developed photoresist model; According to the light field distribution in the initial negative tone developed photoresist model and the acid concentration in the photoresist, constructing a distribution function S of the acid concentration in the photoresist based on the light field distribution; The developer concentration consumption is directly proportional to the acid concentration consumption in the photoresist, and a developer concentration distribution function D is constructed based on the acid concentration distribution function S in the photoresist; A step of constructing a developer concentration diffusion calculation formula R for calculating the diffusion results of developers of different concentrations based on a concentration distribution function D of the developer; A step of simulating the development process using a developer concentration diffusion calculation formula R to obtain a pseudo-negative developed photoresist pattern after development; comparing the pseudo-negative developed photoresist pattern with related data in a preset pattern, and if the pseudo-negative developed photoresist pattern satisfies a preset criterion, setting the pseudo-negative developed photoresist pattern as a real negative developed photoresist pattern; The present invention provides a method for optimizing a negative developing photoresist model, comprising:

[0006] Preferably, the step of constructing a distribution function S of the acid concentration in the photoresist based on the light field distribution in the initial negative development photoresist model and the acid concentration in the photoresist specifically includes: Acquire light field distribution data based on the position of a mask pattern pixel point from an initial negative photoresist model, and construct a light field distribution function E(x, y) based on the acquired light field distribution data, which is a function related to pixel point position information (x, y) based on pixel point position information; and constructing an acid concentration distribution function S(x, y) in the photoresist based on the optical field distribution function E(x, y), which is a correlation function S(x, y) = F(E(x, y)) of the optical field distribution function E(x, y).

[0007] JPEG2025501666000002.jpg17170

[0008] Preferably, the step of constructing a concentration distribution function D of the developer based on the distribution function S of the acid concentration in the photoresist specifically includes: determining a consumption rate of the developer and the acid in the photoresist based on a chemical reaction formula of the acid and the developer in the photoresist; and constructing a concentration distribution function of the developer from the consumption rates of the acid and the developer in the photoresist, such that D(x, y)=F(S(x, y)).

[0009] JPEG2025501666000003.jpg11170

[0010] Preferably, the step of constructing a developer concentration diffusion calculation formula R for calculating the diffusion results of developers of different concentrations based on the developer concentration distribution function D includes the steps of: A step of constructing a concentration diffusion direction expression D1 of the developer; constructing a concentration diffusion intensity expression D2 of the developer; Includes.

[0011] JPEG2025501666000004.jpg20170

[0012] Preferably, the step of constructing a developer concentration diffusion calculation formula R for calculating the diffusion results of developers of different concentrations based on the developer concentration distribution function D includes the steps of: The method includes a step of obtaining the developer concentration diffusion direction and intensity per unit area from the developer concentration diffusion direction expression D1 and the diffusion intensity expression D2, calculating the developer diffusion result per unit area based on the developer concentration distribution function D, constructing a developer concentration diffusion calculation formula R(x, y) based on the developer concentration diffusion direction expression D1 and the diffusion intensity expression D2, and integrating the developer diffusion result per unit area, thereby simulating the diffusion of the developer.

[0013] JPEG2025501666000005.jpg32170

[0014] Preferably, further comprising: The factors for comparing the developed pseudo negative tone photoresist pattern with the preset pattern include steps including the root mean square of the preset key size and / or the grid point error.

[0015] The optimization method for the negative developing photoresist model of the present invention has the following advantages over the prior art:

[0016] 1. The optimization method of the negative development photoresist model of the present invention is a simulation method of negative development based on developer density distribution. First, the distribution function correlation function S of acid concentration in photoresist is constructed according to the relevant data of the light field distribution in the initial negative development photoresist model. Then, in the development process, the developer reacts with the acid in the photoresist chemically. How much developer is there, the acid will be consumed in proportion according to the chemical reaction formula. Therefore, the concentration consumption of the developer is considered to be directly proportional to the concentration consumption of the acid in the photoresist. Based on this, the concentration distribution function of the developer can be quickly constructed to be D. The concentration distribution data of the developer can be obtained by the concentration distribution function D. When the concentration of the developer distributed in different regions is different, it will cause a diffusion effect. Therefore, the developer concentration diffusion calculation formula R can be constructed according to the concentration distribution function D. Since the development process is actually a process of chemical reaction between photoresist and developer, the change in developer concentration is directly related to the photoresist image, and since the photoresist and developer react in the negative development, the change in developer concentration can tell which photoresist area has reacted, and the photoresist image after reaction can also be known, so that the change in developer concentration distribution during the development process can be simulated with high accuracy to simulate the change in photoresist during the development process with high accuracy, thereby obtaining a high-precision negative development photoresist pattern after development. This method achieves both modeling speed and accuracy, and while ensuring accuracy, the modeling speed can be comparable to negative development.

[0017] 2. The light field distribution function E in the present invention is constructed according to the acquired light field distribution data, and the acid concentration distribution function S in the photoresist is constructed according to the light field distribution function E. Therefore, if the light field distribution function E is a function related to (x, y), then the acid concentration distribution function S in the photoresist is also a function related to (x, y). This design makes it easy to group variables together, facilitates calculation, reduces the amount of calculation during optimization, and is advantageous to improving the calculation speed. In addition, the light field distribution data in the present invention is obtained based on the position of the pixel points of the mask pattern, which is highly accurate.

[0018] JPEG2025501666000006.jpg20170

[0019] 4. The concentration distribution function D of the developer in the present invention is constructed based on the consumption ratio of the developer and the acid in the photoresist, and is a function related to (x, y). This design is advantageous in that it is easy to group variables together, facilitates calculation, reduces the amount of calculation during optimization, and improves calculation speed.

[0020] JPEG2025501666000007.jpg38170

[0021] JPEG2025501666000008.jpg37170

[0022] JPEG2025501666000009.jpg21170

[0023] 8. In the present invention, the developer concentration diffusion calculation formula R is based on calculus idea to accumulate the concentration diffusion, and there is no need to perform pure brute force convolution calculation, which further reduces the amount of calculation during modeling and improves the overall calculation speed.

[0024] JPEG2025501666000010.jpg26170

[0025] 10. In the present invention, the comparison factors include the magnitude of the root mean square of the preset key size and / or the magnitude of the lattice point error, so that the comparison is comprehensive and the comparison error situation can be effectively avoided.

[0026] In the following, in order to more clearly explain the technical solutions in the embodiments of the present invention, we will briefly describe the drawings that need to be used in the description of the embodiments or prior art. The drawings in the following description are only some embodiments of the present invention, and it is obvious to those skilled in the art that other drawings can also be obtained based on these drawings without creative ingenuity. [Brief description of the drawings]

[0027] [Figure 1] FIG. 2 is a block diagram of a method for optimizing a negative developing photoresist model according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a light field distribution diagram of a photoresist region selected in the optimization method for a negative development photoresist model according to the first embodiment of the present invention. [Diagram 3] FIG. 2 is a light field distribution diagram after the diffusion of the developer in the photoresist region selected in the optimization method for the negative development photoresist model according to the first embodiment of the present invention is completed. [Figure 4] FIG. 4 is a light field distribution diagram of another photoresist region selected in the optimization method for the negative development photoresist model according to the first embodiment of the present invention. [Diagram 5] FIG. 11 is a light field distribution diagram after the diffusion of the developer is completed in another photoresist region selected in the optimization method for the negative development photoresist model in the first embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] In order to clarify the objectives, technical solutions and advantages of the present invention, the present invention will be described in more detail with reference to the drawings and examples below. It should be noted that the specific examples described herein are merely for the purpose of illustrating the present invention and are not intended to limit the present invention.

[0029] The terms "vertical", "horizontal", "left", "right", "top", "bottom", "upper left", "upper right", "lower left", "lower right" and similar expressions used in this specification are for purposes of explanation only.

[0030] Referring to FIG. 1 to FIG. 5, the first embodiment of the present invention is as follows: Step S1 of obtaining an initial negative developed photoresist model; Step S2: constructing a distribution function S of acid concentration in the photoresist based on the light field distribution according to the light field distribution in the initial negative-tone developed photoresist model and the acid concentration in the photoresist; Step S3 of constructing a concentration distribution function D of the developer based on the distribution function S of the acid concentration in the photoresist; Step S4 of constructing a developer concentration diffusion calculation formula R for calculating the diffusion results of developers of different concentrations based on the developer concentration distribution function D; Step S5 of simulating the development process using a developer concentration diffusion calculation formula R to obtain a pseudo-negative developed photoresist pattern after development; The method for optimizing a negative-tone developed photoresist model includes a step S6 of comparing the pseudo-negative developed photoresist pattern with related data in a preset pattern, and if the pseudo-negative developed photoresist pattern satisfies a preset criterion, setting the pseudo-negative developed photoresist pattern as a real negative-tone developed photoresist pattern.

[0031] The optimization method of the negative development photoresist model of the present invention is a negative development simulation method calculated based on the developer density distribution. First, the correlation function S of the distribution function of the acid concentration in the photoresist is constructed according to the relevant data of the light field distribution in the initial negative development photoresist model. Then, in the development process, the developer reacts with the acid in the photoresist chemically. How much developer is available will consume a proportion of the acid according to the chemical reaction formula. Therefore, it is considered that the concentration consumption of the developer is directly proportional to the concentration consumption of the acid in the photoresist. Based on this, the concentration distribution function of the developer can be quickly constructed, and the concentration distribution data of the developer can be obtained according to the concentration distribution function D of the developer. When the concentration of the developer distributed in different regions is different, a diffusion effect will occur, so that the developer Based on the concentration distribution function D, a developer concentration diffusion calculation formula R is constructed; during the development process, the photoresist chemically reacts with the developer, so the concentration change of the developer is directly related to the photoresist image; during negative development, there is a part where the photoresist and the developer react, so the concentration change of the developer can tell which area of ​​the photoresist has reacted, and the photoresist image after the reaction can also be known; by simulating the change in the concentration distribution of the developer in the development process with high accuracy, the change in the photoresist in the development process with high accuracy can be obtained as a highly accurate negative development photoresist pattern after development; it is understood that this method can achieve both modeling speed and accuracy, ensure accuracy, and make the modeling speed comparable to negative development.

[0032] Furthermore, step S1 specifically includes the following steps: Step S11 includes selecting at least a portion of the photoresist as a target area and generating a mask image of a predetermined size; Specifically, in this embodiment, a mask image with a pixel size of 512*512 is generated, and it is understood that the pixel size of the template image can be adjusted according to actual needs; and step S12 of constructing an initial negative developed photoresist model using conventional modeling techniques for the generated mask image of a predetermined size.

[0033] Furthermore, step S2 specifically includes the following steps: The method includes a step S21 of acquiring light field distribution data based on the position of a mask pattern pixel point from an initial negative photoresist model, and constructing a light field distribution function E(x, y) based on the acquired light field distribution data and related to the pixel point position information (x, y); Specifically, the optical field distribution function is a statistical distribution function result of different light intensities at different positions due to causes such as light transmission, reflection or refraction. It is understood that different optical models have different optical field distributions, and therefore the optical field distribution functions E(x, y) constructed based on different optical models are also different; The method includes a step S22 of constructing an acid concentration distribution function S(x, y) in the photoresist based on the optical field distribution function E(x, y), which is a correlation function S(x, y) = F(E(x, y)) of the optical field distribution function E(x, y).

[0034] The light field distribution function E in the present invention is constructed according to the acquired light field distribution data, and the acid concentration distribution function S in the photoresist is constructed according to the light field distribution function E. Therefore, if the light field distribution function E is a function related to (x, y), then the acid concentration distribution function S in the photoresist is also a function related to (x, y). This design makes it easy to group variables together, facilitates calculation, reduces the amount of calculation during optimization, and is advantageous to improving the calculation speed. In addition, it can be understood that the light field distribution data in the present invention is obtained based on the pixel points of the mask pattern as the position basis, and is highly accurate.

[0035] JPEG2025501666000011.jpg17170

[0036] JPEG2025501666000012.jpg18170

[0037] JPEG2025501666000013.jpg20170

[0038] A photoacid generator is a compound that can be decomposed by radiation such as light, radiation, or plasma to generate a specific acid, and the generated acid can decompose or crosslink an acid-sensitive resin.

[0039] Furthermore, step S3 specifically includes the steps of: A step S31 of determining a consumption rate of the developer and the acid in the photoresist based on a chemical reaction formula of the acid in the photoresist and the developer; During the development process, the developer reacts with the acid in the photoresist chemically, and depending on how much developer there is, the developer will consume a proportion of the acid according to the chemical reaction formula. Therefore, it is considered that the concentration consumption of the developer is directly proportional to the concentration consumption of the acid in the photoresist. Therefore, it is understood that the consumption ratio of the developer and the acid in the photoresist can be determined according to the chemical reaction formula between the developer and the acid in the photoresist. A step 32 includes constructing a concentration distribution function of the developer from the consumption rates of the acid and the developer in the photoresist, such that D(x,y)=F(S(x,y)).

[0040] JPEG2025501666000014.jpg12170

[0041] JPEG2025501666000015.jpg37170

[0042] Furthermore, step S4 specifically includes the following steps: Step S31 of constructing a concentration diffusion direction expression D1 of the developer; Step S32 of constructing a concentration diffusion intensity expression D2 of the developer; Includes.

[0043] JPEG2025501666000016.jpg36170

[0044] JPEG2025501666000017.jpg36170

[0045] Furthermore, step S4 specifically includes the following steps: The method includes a step of obtaining the developer concentration diffusion direction and intensity per unit area from the developer concentration diffusion direction expression D1 and the diffusion intensity expression D2, calculating the developer diffusion result per unit area based on the developer concentration distribution function D, constructing a developer concentration diffusion calculation formula R(x, y) based on the developer concentration diffusion direction expression D1 and the diffusion intensity expression D2, and integrating the developer diffusion result per unit area, thereby simulating the diffusion of the developer.

[0046] The developer concentration diffusion calculation formula R can obtain the total diffusion result of the developer by accumulating the diffusion result of the developer per unit area of ​​the selected region, and a highly accurate negative development photoresist model can be obtained by optimizing the conventional calculation photolithography model based on the calculated total diffusion result of the developer. This method can achieve both modeling speed and accuracy, and while ensuring accuracy, the modeling speed can be made comparable to that of positive development. In addition, the developer concentration diffusion calculation formula R accumulates the concentration diffusion based on calculus ideas, and there is no need to perform pure brute force convolution calculation, which further reduces the amount of calculation during modeling and improves the overall calculation speed.

[0047] JPEG2025501666000018.jpg20170

[0048] JPEG2025501666000019.jpg27170

[0049] Furthermore, in step S5, a highly accurate negative photoresist pattern is obtained after development by simulating with high accuracy the change in the concentration distribution of the developer during the development process and simulating with high accuracy the change in the photoresist during the development process.

[0050] JPEG2025501666000020.jpg17170

[0051] Furthermore, in step S6, if the comparison result between the negative tone developed photoresist pattern and the preset pattern related data cannot meet the preset standard, the high precision photoresist pattern will continue to be optimized until it reaches the preset standard. It is understood that the specific preset standard can be set by oneself according to the type of data to be compared.

[0052] Specifically, in this embodiment, the preset pattern in step S6 is a model design drawing, and the comparison between the high-precision negative developed photoresist pattern after development and the related data of the preset pattern includes a deformation / error comparison of the critical dimension, and the method of performing the deformation / error comparison of the critical dimension includes comparing the magnitude of the root mean square of the critical dimension and comparing the grid point error of the critical dimension, and it is understood that the smaller the magnitude of the root mean square of the critical dimension and the grid point error are, the more preferable.

[0053] In other embodiments, other comparison factors may be added during the comparison.

[0054] In the present invention, it is understood that it is advantageous to compare the high-precision negative-tone developed photoresist pattern after development with a preset pattern, and if it does not meet the preset standard, to continue optimizing the modeling result and ensure the accuracy of the negative-tone developed photoresist model.

[0055] Specifically, in this embodiment, the preset criterion includes whether the root mean square of the optimized model is less than 2, and in other embodiments, the criterion may be other numerical values ​​that are larger or smaller.

[0056] Furthermore, continuing to optimize the model may involve further optimizing equations such as S(x,y), D(x,y), etc.

[0057] 2 to 5, FIG. 2 shows the light field distribution map in the initially selected photoresist region, FIG. 3 shows the light field distribution map after the development effect in the photoresist due to different developer densities, different gradation patches show different light field intensities, and it is clear from the comparison between FIG. 2 and FIG. 3 that after the developer is diffused, the image has already undergone a very large change; similarly, FIG. 4 and FIG. 5 show another set of contrasts, including the light field distribution map in the initially selected photoresist region (FIG. 4) and the light field distribution map after the development effect in the photoresist due to different developer densities (FIG. 5); the conventional negative development photoresist model cannot simulate this change from FIG. 2 to FIG. 3 or from FIG. 4 to FIG. 5, but can be optimized by the optimization method of the negative development photoresist model of the present application, and the development process is simulated by the developer concentration diffusion calculation formula R, and the change in the concentration distribution of the developer during the development process is highly accurately simulated to highly accurately simulate the change in the photoresist during the development process, thereby obtaining a highly accurate negative development photoresist pattern after development.

[0058] The optimization method for the negative developing photoresist model of the present invention has the following advantages over the prior art:

[0059] 1. The optimization method of the negative development photoresist model of the present invention is a negative development simulation method calculated based on the developer density distribution. First, the distribution function correlation function S of the acid concentration in the photoresist is constructed according to the relevant data of the light field distribution in the initial negative development photoresist model. Then, in the development process, the developer reacts with the acid in the photoresist chemically. How much developer there is will consume a proportion of the acid according to the chemical reaction formula. Therefore, it is considered that the concentration consumption of the developer is directly proportional to the concentration consumption of the acid in the photoresist. Based on this, the concentration distribution function of the developer can be quickly constructed as follows. The concentration distribution data of the developer can be obtained according to the concentration distribution function D of the developer. When the concentration of the developer distributed in different regions is different, a diffusion effect will occur. Therefore, a developer concentration diffusion calculation formula R is constructed based on the developer concentration distribution function D; during the development process, the photoresist will chemically react with the developer, so the change in developer concentration is directly related to the photoresist image; during negative development, there is a part where the photoresist and the developer react, so the change in developer concentration can tell which area of ​​the photoresist has reacted, and the photoresist image after the reaction can also be known; by simulating the change in the developer concentration distribution in the development process with high accuracy, the change in the photoresist change in the development process with high accuracy can be obtained as a highly accurate negative development photoresist pattern after development; this method achieves both modeling speed and accuracy, while ensuring accuracy, and the modeling speed can be comparable to negative development.

[0060] 2. The light field distribution function E in the present invention is constructed according to the acquired light field distribution data, and the acid concentration distribution function S in the photoresist is constructed according to the light field distribution function E. Therefore, if the light field distribution function E is a function related to (x, y), then the acid concentration distribution function S in the photoresist is also a function related to (x, y). This design makes it easy to group variables together, facilitates calculation, reduces the amount of calculation during optimization, and is advantageous to improving the calculation speed. In addition, the light field distribution data in the present invention is obtained based on the position of the pixel points of the mask pattern, which is highly accurate.

[0061] JPEG2025501666000021.jpg20170

[0062] 4. The concentration distribution function D of the developer in the present invention is constructed based on the consumption ratio of the developer and the acid in the photoresist, and is a function related to (x, y). This design is advantageous in that it is easy to group variables together, facilitates calculation, reduces the amount of calculation during optimization, and improves calculation speed.

[0063] JPEG2025501666000022.jpg37170

[0064] JPEG2025501666000023.jpg36170

[0065] JPEG2025501666000024.jpg20170

[0066] 8. In the present invention, the developer concentration diffusion calculation formula R is based on calculus idea to accumulate the concentration diffusion, and there is no need to perform pure brute force convolution calculation, which further reduces the amount of calculation during modeling and improves the overall calculation speed.

[0067] JPEG2025501666000025.jpg26170

[0068] 10. The comparison factors in the present invention include the magnitude of the root mean square of the preset key size and / or the magnitude of the lattice point error, so that the comparison is comprehensive and the comparison error situation can be effectively avoided.

[0069] The above is a detailed description of the optimization method for the negative development photoresist model disclosed in the embodiments of the present invention. In the present specification, specific examples are used to explain the principles and embodiments of the present invention. The above explanation of the embodiments is for the purpose of facilitating the understanding of the method of the present invention and its gist. At the same time, those skilled in the art may make changes in the specific embodiments and scope of application based on the concept of the present invention. As mentioned above, the contents of this specification do not limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the principle of the present invention should be included in the scope of the present invention.

Claims

1. obtaining an initial negative tone developed photoresist model; constructing a distribution function S of acid concentration in the photoresist based on the light field distribution in the initial negative tone developed photoresist model and the acid concentration in the photoresist; The developer concentration consumption is directly proportional to the acid concentration consumption in the photoresist, and a developer concentration distribution function D is constructed based on the distribution function S of the acid concentration in the photoresist; A step of constructing a developer concentration diffusion calculation formula R for calculating the diffusion results of developers of different concentrations based on a concentration distribution function D of the developer; A step of simulating a development process using a developer concentration diffusion calculation formula R to obtain a pseudo-negative developed photoresist pattern after development; comparing the pseudo-negative developed photoresist pattern with related data in a preset pattern, and if the pseudo-negative developed photoresist pattern satisfies a preset criterion, setting the pseudo-negative developed photoresist pattern as a real negative developed photoresist pattern; 1. A method for optimizing a negative developing photoresist model, comprising:

2. The step of constructing a distribution function S of acid concentration in the photoresist based on the light field distribution according to the light field distribution in the initial negative development photoresist model and the acid concentration in the photoresist is specifically Acquire light field distribution data based on the position of a mask pattern pixel point from an initial negative photoresist model, and construct a light field distribution function E(x, y) based on the acquired light field distribution data, which is a function related to pixel point position information (x, y) based on pixel point position information; constructing an acid concentration distribution function S(x,y) in the photoresist based on the optical field distribution function E(x,y), which is a correlation function S(x,y)=F(E(x,y)) of the optical field distribution function E(x,y); 2. The method of claim 1, further comprising:

3.

4. The step of constructing a concentration distribution function D of the developer based on the distribution function S of the acid concentration in the photoresist specifically includes the following steps: determining a consumption rate of the developer and the acid in the photoresist based on a chemical reaction formula of the acid and the developer in the photoresist; constructing a concentration distribution function of the developer from the consumption rates of the acid and the developer in the photoresist such that D(x,y)=F(S(x,y)); 2. The method of claim 1, further comprising:

5.

6. Before constructing a developer concentration diffusion calculation formula R for calculating the diffusion result of a developer having a different concentration based on the concentration distribution function D of the developer, specifically, A step of constructing a concentration diffusion direction expression D1 of the developer; constructing a concentration diffusion intensity expression D2 of the developer; 2. The method of claim 1, further comprising:

7.

8. The step of constructing a developer concentration diffusion calculation formula R for calculating the diffusion results of developers of different concentrations based on the developer concentration distribution function D is specifically as follows: The method for optimizing a negative developing photoresist model according to claim 7, further comprising the steps of: obtaining the concentration diffusion direction and intensity of the developer per unit area from the developer concentration diffusion direction expression D1 and the diffusion intensity expression D2; calculating the diffusion result of the developer per unit area based on the developer concentration distribution function D; constructing a developer concentration diffusion calculation formula R(x, y) based on the developer concentration diffusion direction expression D1 and the diffusion intensity expression D2; and integrating the diffusion result of the developer per unit area to simulate the diffusion of the developer.

9.

10. 8. The method for optimizing a negative-tone development photoresist model according to claim 7, wherein the comparison factors when comparing the high-precision negative-tone development photoresist pattern after development with the preset pattern include the root mean square of the preset key size and / or the lattice point error.

11. 11. The method of claim 10, wherein the preset criterion includes whether the root mean square of the optimized model is less than 2.

12. 6. The method for optimizing a negative developing photoresist model according to claim 5, wherein the instantaneous consumption speed of the developer is used in the constructed concentration distribution function of the developer.

13. 13. The method of claim 12, wherein the developer concentration distribution function D is related to the acid concentration distribution function S in the photoresist by a crosslinking reaction rate constant.

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