Modeling and calibration method for photoetching negative development process

Abstract

The invention belongs to the technical field of photoetching and computational photoetching, and particularly discloses a modeling and calibration method for a photoetching negative development process, and the modeling method comprises the steps: calibrating a preset photoresist model based on an exposure space image and a preset calibration data set, and obtaining a pre-calibrated photoresist model; inputting the exposure space image into the pre-calibrated photoresist model to obtain a photoresist image, and constructing a negative development shrinkage effect feature item based on the exposure space image and the photoresist image; and combining the negative development shrinkage effect characteristic item with the pre-calibrated photoresist model to establish a negative development photoresist model. The method can solve the problem that the positive development photoresist model cannot represent the shrinkage effect, so that the negative development process cannot be represented, and the model precision is improved.

Description

Technical Field

[0001] The present application belongs to the field of photolithography and computational lithography technology, and more specifically, relates to a modeling and calibration method for a photolithography negative development process. Background Art

[0002] With the continuous scaling of semiconductor process nodes, the negative tone development (NTD) process has been proposed and widely adopted at technology nodes of 20nm and below. Unlike positive tone development (PTD), negative tone development can cause photoresist shrinkage during the post-exposure-bake (PEB) process. While this shrinkage causes a loss of resist thickness in the exposed areas, it significantly impacts the post-development resist profile and critical dimensions (CDs). Therefore, physical modeling of the negative tone development process, particularly the shrinkage effect, is essential.

[0003] Current positive photolithography development models typically characterize the development process by selecting appropriate functional features based on the standard development rate and the reaction-diffusion effect of post-bake. The model is then calibrated using experimental data and used for full-chip photoresist profile shape prediction and critical dimension calculation. However, for negative photoresists, existing positive development models cannot account for their unique shrinkage effects, making it difficult to obtain a photoresist model that meets the required accuracy through calibration. Summary of the Invention

[0004] In view of the defects of the prior art, the purpose of this application is to provide a modeling and calibration method for the negative development process of lithography, aiming to solve the problem of low accuracy caused by the inability of the existing positive development model to describe the shrinkage effect of the negative development photoresist.

[0005] To achieve the above objectives, in a first aspect, the present application provides a modeling method for a photolithography negative development process, comprising: Calibrate the preset photoresist model based on the exposure aerial image and the preset calibration data set to obtain a pre-calibrated photoresist model; Inputting the exposure aerial image into the pre-calibrated photoresist model to obtain a photoresist image, and constructing a negative development shrinkage effect characteristic item based on the exposure aerial image and the photoresist image; The negative development shrinkage effect characteristic item is combined with the pre-calibrated photoresist model to establish a negative development photoresist model.

[0006] This application starts from the physical process of the negative development process, constructs a negative development shrinkage effect characteristic term, and combines it with the photoresist model. Based on this, it realizes the characterization of the shrinkage effect unique to negative development, and solves the problem that the PTD photoresist model cannot characterize the shrinkage effect and therefore cannot characterize the negative development process. At the same time, the correction effect of the negative development shrinkage effect characteristic term on the photoresist profile is related to the initial photoresist profile graphic. Therefore, pre-calibration is required to ensure applicability and improve model accuracy.

[0007] According to a modeling method for a photolithography negative development process provided in the present application, the preset calibration data set includes one or more of the following: Key dimension dataset measured after photoresist is exposed by an actual lithography machine; Key profile dataset measured after photoresist exposure on an actual lithography machine; A photoresist image or profile that is produced by exact simulation.

[0008] According to a modeling method for a photolithography negative development process provided by the present application, the method performs an initial calibration on a preset photoresist model based on the exposure aerial image and a preset calibration data set to obtain a pre-calibrated photoresist model, including: Inputting the exposure aerial image into a preset photoresist model to obtain first output data; Comparing the first output data with the preset calibration data set to obtain a first comparison result; The coefficients of the preset photoresist model are adjusted based on the first comparison result until the comparison error is minimized.

[0009] According to a modeling method for a photolithography negative development process provided in the present application, constructing a negative development shrinkage effect characteristic item based on the exposure aerial image and the photoresist image includes: extracting a photoresist profile of the photoresist image; obtaining a distance distribution image based on the photoresist profile; Based on the distance distribution image, calculating the direction field and constructing the contraction stress function; obtaining a void distribution image based on the exposed aerial image; Obtaining a displacement distribution caused by a shrinkage effect based on the shrinkage stress function and the void distribution image; Calculating a gradient image of the photoresist image based on the pre-calibrated photoresist model; The negative development shrinkage effect characteristic item is obtained based on the displacement caused by the shrinkage effect and the gradient image of the photoresist image.

[0010] This application generates a void distribution image based on the spatial image of photolithography exposure, establishes a stress function of the voids on the surrounding area, and for a pre-calibrated PTD photoresist image, accumulates the stress of the voids at each location on its edge contour through convolution calculation, and converts it into a shrinkage effect characteristic term. Based on this, the shrinkage effect unique to negative development is characterized, solving the problem that the PTD photoresist model cannot characterize the shrinkage effect and therefore cannot characterize the negative development process.

[0011] According to a modeling method for a photolithography negative development process provided in the present application, obtaining a distance distribution image based on the photoresist profile includes any one of the following: Based on the photoresist profile, a distance distribution image is obtained by a rapid scanning method; Based on the photoresist profile, a distance distribution image is obtained by a level set method; Based on the photoresist profile, a distance distribution image is obtained by a rasterization method.

[0012] According to a modeling method for a photolithography negative development process provided in the present application, the method of calculating the direction field and constructing the shrinkage stress function based on the distance distribution image includes: Calculating the partial derivatives of the distance distribution image in the x and y directions as the direction field; Setting a stress characteristic function, wherein the stress characteristic function is used to describe the relationship between the stress and distance of the gap generated by gas evaporation in the post-baking process to the surrounding position; A shrinkage stress function is constructed based on the stress characteristic function and the distance distribution image.

[0013] According to a modeling method for a photolithography negative development process provided in the present application, obtaining a void distribution image based on the exposure aerial image includes: Inputting the exposure aerial image into a post-exposure baking PEB model to obtain a void distribution image output by the PEB model; or Constructing the relationship between the exposure aerial image and the void distribution image by using an exponential function to obtain the void distribution image; or, The relationship between the exposure aerial image and the void distribution image is approximately characterized by a Sigmoid function to obtain the void distribution image.

[0014] According to a modeling method for a photolithography negative development process provided by the present application, obtaining the displacement caused by the shrinkage effect based on the shrinkage stress function and the void distribution image includes: The shrinkage stress function is convolved with the void distribution image to calculate the displacement caused by the shrinkage effect.

[0015] According to a modeling method for a photolithography negative development process provided by the present application, the negative development shrinkage effect characteristic term is combined with the pre-calibrated photoresist model to establish a negative development photoresist model, including: One or more negative development shrinkage effect characteristic terms are linearly combined or rationally combined with the pre-calibrated photoresist model.

[0016] In a second aspect, the present application provides a calibration method for a photolithography negative development process, which is applied to the modeling method for the photolithography negative development process provided in the first aspect, comprising: Calibrate the preset photoresist model based on the exposure aerial image and the preset calibration data set to obtain the preset photoresist model calibration result parameters; inputting the exposure aerial image into a negative development photoresist model to obtain second output data; Comparing the second output data with the preset calibration data set to obtain a second comparison result; Adjusting the coefficients of the negative development photoresist model based on the second comparison result until the comparison error is minimized, thereby obtaining a characteristic item parameter of the negative development shrinkage effect; All parameters of the negative development photoresist model are jointly calibrated based on the initial results of the preset photoresist model calibration result parameters and the initial results of the negative development shrinkage effect characteristic item parameters to obtain a calibrated negative development photoresist model.

[0017] After combining the shrinkage effect item, the negative development shrinkage effect characteristic item and the pre-calibrated photoresist model, this application calibrates the negative development photoresist model to obtain the negative development shrinkage effect characteristic item parameters, and then combines the preset photoresist model calibration result parameters to jointly calibrate all parameters of the negative development photoresist model, which can improve the accuracy of the negative development photoresist model.

[0018] In a third aspect, the present application provides a modeling device for a photolithography negative development process, comprising: A first calibration module is used to calibrate a preset photoresist model based on the exposure aerial image and a preset calibration data set to obtain a pre-calibrated photoresist model; a construction module, configured to input the exposure aerial image into the pre-calibrated photoresist model to obtain a photoresist image, and construct a negative development shrinkage effect characteristic item based on the exposure aerial image and the photoresist image; The combination module is used to combine the negative development shrinkage effect characteristic item with the pre-calibrated photoresist model to establish a negative development photoresist model.

[0019] In a fourth aspect, the present application provides a calibration device for a photolithography negative development process, comprising: A second calibration module is used to calibrate the preset photoresist model based on the exposure aerial image and the preset calibration data set to obtain calibration result parameters of the preset photoresist model; An input module, configured to input the exposure aerial image into a negative development photoresist model to obtain second output data; a comparison module, configured to compare the second output data with the preset calibration data set to obtain a second comparison result; an adjusting module, configured to adjust the coefficients of the negative development photoresist model based on the second comparison result until the comparison error is minimized, thereby obtaining a characteristic item parameter of the negative development shrinkage effect; The calibration module is used to jointly calibrate all parameters of the negative development photoresist model based on the initial results of the preset photoresist model calibration result parameters and the initial results of the negative development shrinkage effect characteristic item parameters to obtain a calibrated negative development photoresist model.

[0020] In a fifth aspect, the present application provides an electronic device comprising: at least one memory for storing programs; and at least one processor for executing the programs stored in the memory. When the programs stored in the memory are executed, the processor is used to execute the modeling method of the photolithography negative development process described in the first aspect or any possible implementation of the first aspect.

[0021] In a sixth aspect, the present application provides an electronic device comprising: at least one memory for storing programs; and at least one processor for executing the programs stored in the memory. When the programs stored in the memory are executed, the processor is used to execute the calibration method of the photolithography negative development process described in any possible implementation of the second aspect.

[0022] In the seventh aspect, the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the modeling method of the photolithography negative development process described in the first aspect or any possible implementation of the first aspect.

[0023] In an eighth aspect, the present application provides a computer-readable storage medium storing a computer program. When the computer program runs on a processor, the processor executes the calibration method of the photolithography negative development process described in the second aspect or any possible implementation of the second aspect.

[0024] In a ninth aspect, the present application provides a computer program product, which, when executed on a processor, enables the processor to execute the modeling method of the photolithography negative development process described in the first aspect or any possible implementation of the first aspect.

[0025] In a tenth aspect, the present application provides a computer program product, which, when running on a processor, enables the processor to execute the calibration method of the photolithography negative development process described in the second aspect or any possible implementation of the second aspect.

[0026] It can be understood that the beneficial effects of the third to tenth aspects mentioned above can be found in the relevant descriptions of the first and second aspects mentioned above, and will not be repeated here.

[0027] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the existing technologies: (1) This application starts from the physical process of the negative development process, constructs the negative development shrinkage effect characteristic term, and combines it with the photoresist model. Based on this, the shrinkage effect unique to negative development is characterized, and the problem that the PTD photoresist model cannot characterize the shrinkage effect and therefore cannot characterize the negative development process is solved. At the same time, the correction effect of the negative development shrinkage effect characteristic term on the photoresist profile is related to the initial photoresist profile pattern. Therefore, pre-calibration is required to ensure applicability and improve model accuracy.

[0028] (2) After combining the shrinkage effect item, the negative development shrinkage effect characteristic item and the pre-calibrated photoresist model, the present application calibrates the negative development photoresist model to obtain the negative development shrinkage effect characteristic item parameters, and then combines the preset photoresist model calibration result parameters to jointly calibrate all parameters of the negative development photoresist model, which can improve the accuracy of the negative development photoresist model. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the present application or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] Figure 1 1 is a flow chart of a modeling method for a photolithography negative development process provided in an embodiment of the present application; Figure 2 1 is a schematic diagram of a modeling process of a negative photolithography development process provided in an embodiment of the present application; Figure 3 1 is a flow chart of a method for modeling and calibrating a photolithography negative development process provided in an embodiment of the present application; Figure 4 This is a method for constructing a shrinkage effect feature item provided in an embodiment of the present application; Figure 5 1 is a flow chart of a calibration method for a photolithography negative development process provided in an embodiment of the present application; Figure 6 1 is a schematic diagram of a model calibration process for a photolithography negative development process provided in an embodiment of the present application; Figure 7 Schematic diagram of the structure of a modeling device for a photolithography negative development process provided in an embodiment of the present application; Figure 8 Schematic diagram of the structure of a calibration device for a photolithography negative development process provided in an embodiment of the present application; Figure 9 It is a structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0032] The term "and / or" as used herein describes an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. The symbol " / " as used herein indicates that the related objects are in an "or" relationship, for example, A / B means either A or B.

[0033] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0034] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more, for example, multiple processing units means two or more processing units, etc.; multiple elements means two or more elements, etc.

[0035] First, let’s introduce the following contents: The shrinkage effect of negative-development photoresist primarily occurs during the post-bake process. Its physicochemical process is as follows: During the post-bake process, a large amount of volatile gases are generated in the photoresist in the exposed areas. These gases evaporate during the bake, creating voids. The collapse of these voids causes photoresist shrinkage. This shrinkage effect not only causes vertical thickness loss within the photoresist but also horizontal displacement within the photoresist, resulting in changes in the sidewall angle and CD of the photoresist profile. This effect is also strongly dependent on the mask pattern and must be accounted for in photoresist modeling and optical proximity correction (OPC) modeling.

[0036] To this end, the present application provides a method for modeling and calibrating a photolithography negative development process, aiming to establish a negative development photoresist model by analyzing the shrinkage effect of the negative development photoresist and establishing characteristic terms to characterize the shrinkage effect.

[0037] Next, combine Figure 1-Figure 4 The modeling method of the photolithography negative development process provided in the embodiments of the present application is introduced.

[0038] Figure 1 This is one of the flow charts of the modeling method of the photolithography negative development process provided in the embodiment of the present application, such as Figure 1 As shown, the method includes the following steps: Step 100, performing an initial calibration on a preset photoresist model based on the exposure aerial image and a preset calibration data set to obtain a pre-calibrated photoresist model; Optionally, the exposure spatial image can be obtained by calculating the optical exposure model part of the lithography model, or it can be obtained through exposure of the actual lithography machine through the light intensity sensor integrated in the silicon wafer workpiece stage. The negative development process modeling and calibration process proposed in this application is not restricted by the exposure spatial image acquisition method.

[0039] Optionally, the preset photoresist model may adopt but is not limited to a PTD model or other photoresist models.

[0040] Optionally, the preset calibration data set may adopt but is not limited to a photoresist profile or a CD set, and the calibration data set acquisition method may adopt but is not limited to photoresist data actually exposed by the lithography machine or photoresist data obtained by first-principles modeling calculation.

[0041] Optionally, the preset photoresist model is calibrated based on the exposure aerial image and the preset calibration data set. When the modeling and calibration reach a level where the model error cannot be reduced by adding and adjusting the characteristic item parameters, the calibration of the preset photoresist model is completed.

[0042] Step 110: inputting the exposure aerial image into a pre-calibrated photoresist model to obtain a photoresist image, and constructing a negative development shrinkage effect feature item based on the exposure aerial image and the photoresist image; The exposure aerial image is input into a pre-calibrated photoresist model to obtain a photoresist image, and then a negative development shrinkage effect feature term is constructed based on the exposure aerial image and the photoresist image.

[0043] Step 120 : Combine the negative development shrinkage effect characteristic term with the pre-calibrated photoresist model to establish a negative development photoresist model.

[0044] Optionally, the combined method may adopt, but is not limited to, taking the negative development shrinkage effect characteristic term as a correction factor, adding it to the pre-calibrated photoresist model to generate a negative development photoresist model.

[0045] The present application provides a modeling method for the negative development process of photolithography. Starting from the physical process of the negative development process, a negative development shrinkage effect characteristic term is constructed and combined with the photoresist model. Based on this, the shrinkage effect unique to negative development is characterized, and the problem that the PTD photoresist model cannot characterize the shrinkage effect and thus cannot characterize the negative development process is solved. At the same time, the correction effect of the negative development shrinkage effect characteristic term on the photoresist profile is related to the initial photoresist profile graphic. Therefore, pre-calibration is required to ensure applicability and improve model accuracy.

[0046] In some embodiments, the preset calibration data set includes one or more of the following: Key dimension dataset measured after photoresist is exposed by an actual lithography machine; Key profile dataset measured after photoresist exposure on an actual lithography machine; A photoresist image or profile that is produced by exact simulation.

[0047] Optionally, the preset calibration data set may adopt but is not limited to one or more of a key dimension data set measured after the photoresist is exposed by an actual photolithography machine, a key contour data set measured after the photoresist is exposed by an actual photolithography machine, and a photoresist image or contour generated by rigorous simulation.

[0048] In some embodiments, step 100 specifically includes: Inputting the exposure aerial image into a preset photoresist model to obtain first output data; Comparing the first output data with a preset calibration data set to obtain a first comparison result; The coefficients of the preset photoresist model are adjusted based on the first comparison result until the comparison error is minimized.

[0049] When calibrating the preset photoresist model, the exposure aerial image is used as input data, the preset photoresist model is input, the output data is calculated, and the output data is compared with the preset calibration data set. The coefficients of the preset photoresist model are modulated until the comparison error is minimized.

[0050] In some embodiments, step 110 specifically includes: Step 1101, extracting the photoresist profile of the photoresist image; Step 1102, obtaining a distance distribution image based on the photoresist profile; Step 1103: Calculate the direction field and construct the contraction stress function based on the distance distribution image; Step 1104: obtaining a void distribution image based on the exposed aerial image; Step 1105 , obtaining the displacement distribution caused by the shrinkage effect based on the shrinkage stress function and the void distribution image; Step 1106, calculating a gradient image of the photoresist image based on the pre-calibrated photoresist model; Step 1107 : Obtain a negative development shrinkage effect characteristic item based on the displacement generated by the shrinkage effect and the gradient image of the photoresist image.

[0051] Figure 2 Schematic diagram of the modeling process of the negative development process of the photolithography provided in the embodiment of the present application. Figure 2 As shown, the modeling process includes the following steps: Step S1, establishing a preset photoresist model, which may be a PTD model or other photoresist model but is not limited to a PTD model; then calibrating the preset photoresist model to a point where the model error cannot be reduced by adding and adjusting the characteristic item parameters; Step S2, constructing a negative development shrinkage effect characteristic term as a correction term for the photoresist image; Step S3: Combine the pre-calibrated photoresist model established in step S1 and the negative development shrinkage effect characteristic item constructed in step S2 to establish a negative development photoresist model.

[0052] Among them, in step S2, the negative development shrinkage effect characteristic term ST is constructed, and the specific form is its displacement factor ST dis With gradient factor ST slope The product of: ST = ST dis ×ST slope The specific construction process includes: Step S21, calculating the photoresist image and extracting the photoresist profile according to the pre-calibrated photoresist model established in step S1; Optionally, the photoresist profile can be extracted by, but not limited to, obtaining one or several two-dimensional profiles of the photoresist top layer, middle layer, and bottom layer; further optionally, several two-dimensional profiles can be used to fit the photoresist three-dimensional profile graphic.

[0053] Step S22: Calculate the gradient of the photoresist image according to the photoresist image obtained in step S21, and use it as the gradient factor part ST of the shrinkage effect feature item. slope ; Step S23: Calculate the stress effect of each gap on the edge of the photoresist, and construct the displacement factor part ST of the shrinkage effect characteristic term. dis .

[0054] The displacement factor constructed in step S23 specifically represents the displacement factor caused by the stress at each location on the photoresist edge profile. It takes the form of the convolution of the void distribution image and the contraction stress image. Its physical meaning is: for a point on the photoresist edge profile, the sum of the stress contributions of all pores and voids within a certain range to that point. The closer the pores and voids are to that point, the greater the contraction stress and the resulting displacement effect. Conversely, the farther away the pores and voids are, the smaller the effect.

[0055] Optionally, in specific applications, it can be x Direction and y Δ in the direction dx and Δ dy The components are calculated separately to facilitate numerical calculation and storage.

[0056] The specific construction process includes: Step S231: Acquire an exposure aerial image. The aerial image can be calculated and acquired through the optical exposure model portion of the lithography model, or acquired through actual exposure in a lithography machine using a light intensity sensor integrated in a silicon wafer workpiece stage. Step S232: setting a function based on the relationship between the gap distribution and the aerial image, and calculating the gap distribution image; setting a function based on the relationship between the gap distribution and the aerial image; Step S233: Calculate a distance distribution image based on the photoresist profile obtained in step S21; the calculated distance distribution image includes direction information, which can be defined as, but not limited to, defining the photoresist edge profile facing inward or outward as a positive direction or a negative direction; preferably, the specific direction at each location points to the direction with the fastest gradient descent; Step S234: Calculate and construct the direction field based on the distance distribution image obtained in step S233, and set the stress characteristic function to calculate and obtain the contraction stress image.

[0057] The construction of the negative development shrinkage effect characteristic term ST proposed in this application is based on the main idea of approximating the shrinkage effect of the pores generated by NTD on the edge of the photoresist near the edge of the photoresist as a correction of a small displacement outward or inward at the edge of the photoresist in the original PTD model. During the modeling process, it is approximated by adding a δI term to describe the equivalent difference δI in the photoresist image brought about by this effect: δx×slope=δI.

[0058] Therefore, the construction of the ST term relies on the local analysis of the photoresist image calculated by the pre-calibrated photoresist model. The premise for the application of this method is that the photoresist profile calculated by the established pre-calibrated model is relatively close to the actual exposed photoresist profile, and the error between the two cannot be too large. Only then is the slope information valid.

[0059] In some embodiments, step 1102 specifically includes any one of the following: Based on the photoresist profile, the distance distribution image is obtained by the rapid scanning method; Based on the photoresist profile, the distance distribution image is obtained by the level set method; Based on the photoresist profile, the distance distribution image is obtained by rasterization method.

[0060] Alternatively, the distance distribution image may be obtained by a fast scanning method, a level set method, or a rasterization method.

[0061] In some embodiments, step 1103 specifically includes: Calculate the partial derivatives of the distance distribution image in the x and y directions as the direction field; Set the stress characteristic function, which is used to describe the relationship between the stress and distance of the gaps generated by gas evaporation during the post-baking process. Based on the stress characteristic function and distance distribution image, the shrinkage stress function is constructed.

[0062] Optionally, the direction field construction method may be adopted but is not limited to obtaining the distance distribution image by taking partial derivatives in the x and y directions. Preferably, the amplitude is normalized after taking the partial derivatives, that is, only the direction information is retained.

[0063] The stress characteristic function is used to describe the shrinkage stress generated by a certain pore void on the surrounding locations. The function form is similar to Hooke's law. The stress is related to the distribution of pore voids after the reaction. For a certain pore void, the magnitude of the stress generated on the surrounding area is related to the distance and decays rapidly with increasing distance.

[0064] Optionally, the stress characteristic function may be, but not limited to, a Gaussian function, or other continuous smooth low-pass filter functions, and the function is applied to the void distribution image to calculate and obtain a contraction stress image.

[0065] In some embodiments, step 1104 specifically includes: Input the exposure spatial image into the post-exposure baking PEB model to obtain the void distribution image output by the PEB model; or Constructing the relationship between the exposure aerial image and the void distribution image through an exponential function to obtain the void distribution image; or, The relationship between the exposure aerial image and the gap distribution image is approximately characterized by the Sigmoid function to obtain the gap distribution image.

[0066] Using space image I( x , y ), calculate the gap distribution image VI( x , y ), the calculation method may be but is not limited to: First, using the PEB model, the spatial image I( x , y ) is used as the input of the PEB model, and the model output is the gap distribution image VI ( x , y ); Second, construct the spatial image I( x , y ) and the gap distribution image VI( x , y ):VI( x , y ) = exp [- α I( x , y )], where α is the diffusion coefficient, which is determined by the properties of the photoresist and the developer; Third, the spatial image I( x , y ) and the gap distribution image VI( x , y ):VI( x , y ) = Sigmoid [I( x , y )].

[0067] In some embodiments, step 1104 specifically includes: The shrinkage stress function is convolved with the void distribution image to calculate the displacement caused by the shrinkage effect.

[0068] Shrinkage stress function and the gap distribution image VI( x , y) to perform convolution and calculate the displacement Δ caused by the contraction effect d :Δ d = VI( x , y ) .

[0069] Preferably, the displacement Δ caused by the shrinkage stress d In the calculation of x Direction and y The distribution of the direction is calculated and stored separately, that is, the displacement Δ generated by the shrinkage stress in the two directions is calculated separately. dx and Δ dy :Δ dx = [VI( x , y )× ] , Δ dy = [VI( x , y )× ] ,in and For the direction field x Direction and y Directional derivative.

[0070] In some embodiments, step 120 specifically includes: One or more negative development shrinkage effect characteristic terms are linearly combined or rationally combined with a pre-calibrated photoresist model.

[0071] Optionally, the method of combining and inversely combining the negative development shrinkage effect characteristic term with the pre-calibrated photoresist model may be to linearly combine or rationally combine one or more negative development shrinkage effect characteristic terms with the pre-calibrated photoresist model.

[0072] Figure 3 Schematic diagram of the process of modeling and calibration of the photolithography negative development process provided in the embodiment of the present application. Figure 3 As shown, in one embodiment of the present application, the method includes the following steps: Step 1: Use D1 to expose the aerial image I ( x , y ), calculate the D3 gap distribution image VI( x , y ).

[0073] Step 2: Establish a pre-calibrated photoresist model and use D1 to expose the spatial image I ( x , y) and D2 preset calibration data set to calibrate the pre-calibrated photoresist model to obtain a pre-calibrated photoresist model P1; Step 3: Expose D1 to the spatial image I ( x , y ) Input the photoresist model pre-calibrated by P1 and obtain the D5 photoresist image RI ( x , y ), and extract the D6 photoresist profile accordingly contour .

[0074] Step 4: D6 photoresist profile obtained according to step 3 contour , using the fast scanning method to calculate the D7 distance distribution image Dist( x , y ).

[0075] Step 5: D7 distance distribution image Dist( x , y ), calculate its x and y Partial derivative in direction { , }, as the D8 direction field φ ( x , y ).

[0076] Step 6: D7 distance distribution image Dist( x , y ), set the stress characteristic function , construct D9 shrinkage stress function .

[0077] Step 7: D9 shrinkage stress function constructed in step 6 Compared with the D3 void distribution image VI obtained in step 1 ( x , y ) to perform convolution and calculate the displacement Δ caused by the D10 contraction effect d :Δ d = VI( x , y ) ].

[0078] Figure 4 This is the method for constructing the shrinkage effect feature item provided in the embodiment of the present application. For steps 3 to 7, as shown in FIG. Figure 4 As shown, the thick solid line is the outline of the photoresist at a certain location contour , the left side of the curve is outside the photoresist outline, and the right side is inside the photoresist outline. For a point P0 on the curve, the space p Point pore voids VI(p ) to generate the shrinkage stress, and the direction field is calculated. φ ( x , y ) at this point is towards the lower right direction, respectively x Direction and y After calculating the partial derivative in the direction, we get Δ dx and Δ dy.

[0079] Step 8: According to Δ dx and Δ dy , and the D5 photoresist image RI obtained in step 3 ( x , y ) gradient image D11, construct D12 negative development shrinkage effect feature item: ,in is the gradient symbol.

[0080] Step 9: Combine the D12 negative development shrinkage effect characteristic item ST obtained in step 8 with the P1 pre-calibrated photoresist model to obtain the P2 negative development photoresist model.

[0081] Next, combine Figure 5-Figure 6 The modeling method of the photolithography negative development process provided in the embodiments of the present application is introduced.

[0082] Figure 5 Schematic diagram of the process of calibrating the negative development process of photolithography provided by the embodiment of the present application. Figure 5 As shown, the method includes the following steps: Step 500, calibrating a preset photoresist model based on the exposure aerial image and a preset calibration data set to obtain calibration result parameters of the preset photoresist model; Step 510, inputting the exposure aerial image into the negative development photoresist model to obtain second output data; Step 520, comparing the second output data with a preset calibration data set to obtain a second comparison result; Step 530 , adjusting the coefficients of the negative development photoresist model based on the second comparison result until the comparison error is minimized, thereby obtaining the characteristic item parameters of the negative development shrinkage effect; Step 540 , jointly calibrate all parameters of the negative development photoresist model based on the initial results of the preset photoresist model calibration result parameters and the initial results of the negative development shrinkage effect characteristic item parameters to obtain a calibrated negative development photoresist model.

[0083] Optionally, when calibrating the negative development photoresist model, similar to the initial calibration, the exposure spatial image can be used as input data, input into the negative development photoresist model, the output data is calculated, compared with the preset calibration data set, and the coefficients of the negative development photoresist model are modulated until the comparison error is minimized.

[0084] Optionally, the preset photoresist model calibration result parameters are parameters that need to be calibrated for the preset photoresist model.

[0085] Optionally, the negative development shrinkage effect characteristic item parameter is a parameter corresponding to the negative development shrinkage effect characteristic item.

[0086] Optionally, the initial result of the calibration result parameter of the preset photoresist model is a parameter result after calibrating the preset photoresist model.

[0087] Optionally, the initial result of the parameter of the negative development shrinkage effect characteristic item is a parameter result after calibrating the negative development photoresist model.

[0088] Based on the initial results of the calibration result parameters of the preset photoresist model and the initial results of the parameters of the negative development shrinkage effect characteristic item, the parameters of the preset photoresist model and the parameters of the negative development shrinkage effect characteristic item are fine-tuned at the same time to expand the solution space, which is conducive to improving the accuracy of the calibrated negative development photoresist model.

[0089] Figure 6 Schematic diagram of the model calibration process of the photolithography negative development process provided in the embodiment of the present application. Figure 6 As shown, the calibration steps are as follows: Step 1a: establish a preset photoresist model M1, obtain an exposure aerial image D1 and a preset calibration data set D2; Step 2a, calibrating the preset photoresist model M1 obtained in step 1a using the exposure aerial image D1 and the preset calibration data set D2, adjusting the calibration coefficients in the pre-calibrated model to obtain a pre-calibrated photoresist model M2; Step 3a, according to the shrinkage effect characteristic term construction method in the photolithography negative development process modeling, calculate and store the shrinkage effect characteristic term ST, and combine it with the pre-calibrated photoresist model to obtain the negative development photoresist model M3; In step 4a, the negative development photoresist model M3 obtained in step 3a is recalibrated using the exposure aerial image D1 and the preset calibration data set D2, and the calibration coefficients in the model are adjusted to obtain a calibrated negative development photoresist model M4.

[0090] The present application provides a calibration method for a photolithography negative development process. After combining a shrinkage effect item, a negative development shrinkage effect characteristic item, and a pre-calibrated photoresist model, the negative development photoresist model is calibrated to obtain parameters of the negative development shrinkage effect characteristic item. Then, all parameters of the negative development photoresist model are jointly calibrated in combination with the preset photoresist model calibration result parameters, which can improve the accuracy of the negative development photoresist model.

[0091] Figure 7 Schematic diagram of a structure of a modeling device for a photolithography negative development process provided in an embodiment of the present application. Figure 7 As shown, the apparatus includes a first calibration module 710, an acquisition module 720, and a combination module 730, wherein: A first calibration module 710 is configured to calibrate a preset photoresist model based on the exposure aerial image and a preset calibration data set to obtain a pre-calibrated photoresist model; A construction module 720 is configured to input the exposure aerial image into a pre-calibrated photoresist model to obtain a photoresist image, and construct a negative development shrinkage effect feature item based on the exposure aerial image and the photoresist image; The combining module 730 is used to combine the negative development shrinkage effect characteristic item with the pre-calibrated photoresist model to establish a negative development photoresist model.

[0092] Figure 8 Schematic diagram of a calibration device for a photolithography negative development process provided by an embodiment of the present application. Figure 8 As shown, the device includes a second calibration module 810, an input module 820, a comparison module 830, an adjustment module 840 and a calibration module 850, wherein: A second calibration module 810 is configured to calibrate a preset photoresist model based on the exposure aerial image and a preset calibration data set to obtain calibration result parameters of the preset photoresist model; An input module 820 is used to input the exposure aerial image into the negative development photoresist model to obtain second output data; a comparison module 830, configured to compare the second output data with a preset calibration data set to obtain a second comparison result; An adjustment module 840 is configured to adjust the coefficients of the negative development photoresist model based on the second comparison result until the comparison error is minimized, thereby obtaining a characteristic item parameter of the negative development shrinkage effect; The calibration module 850 is used to jointly calibrate all parameters of the negative development photoresist model based on the initial results of the preset photoresist model calibration result parameters and the initial results of the negative development shrinkage effect characteristic item parameters to obtain a calibrated negative development photoresist model.

[0093] Based on the method in the above embodiment, Figure 9An example of a physical structure diagram of an electronic device is shown below. Figure 9 As shown, an embodiment of the present application provides an electronic device, which may include: a processor 910, a communication interface 920, a memory 930, and a communication bus 940, wherein the processor 910, the communication interface 920, and the memory 930 communicate with each other via the communication bus 940. The processor 910 can call the logic instructions in the memory 930 to execute the modeling method of the photolithography negative development process and the calibration method of the photolithography negative development process in the above-mentioned embodiment.

[0094] In addition, the logic instructions in the aforementioned memory 930 can be implemented in the form of a software functional unit and, when sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the portion that contributes to the prior art, or the portion of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the modeling method and calibration method of the photolithography negative development process described in various embodiments of the present application.

[0095] Based on the method in the above embodiment, an embodiment of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program runs on a processor, the processor executes the modeling method of the lithography negative development process and the calibration method of the lithography negative development process in the above embodiment.

[0096] Based on the method in the above embodiment, an embodiment of the present application provides a computer program product. When the computer program product runs on a processor, the processor executes the modeling method and calibration method of the photolithography negative development process in the above embodiment.

[0097] It is understood that the processor in the embodiments of the present application may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), other programmable logic devices, transistor logic devices, hardware components, or any combination thereof. The general-purpose processor may be a microprocessor or any conventional processor.

[0098] The method steps in the embodiments of the present application can be implemented by hardware or by a processor executing software instructions. The software instructions can be composed of corresponding software modules, which can be stored in random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, mobile hard disks, CD-ROMs, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be an integral part of the processor. The processor and the storage medium can be located in an ASIC.

[0099] The above embodiments can be implemented in whole or in part through software, hardware, firmware, or any combination thereof. When implemented using software, they can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loaded and executed on a computer, the computer program instructions fully or partially produce the processes or functions described in the embodiments of this application. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted via the computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that can be accessed by a computer, or a data storage device such as a server or data center that integrates one or more available media. The available medium can be magnetic media (e.g., floppy disk, hard disk, tape), optical media (e.g., DVD), or semiconductor media (e.g., solid-state drive (SSD)).

[0100] It will be understood that the various numerical numbers involved in the embodiments of the present application are merely distinctions for the convenience of description and are not intended to limit the scope of the embodiments of the present application.

[0101] It is easy for those skilled in the art to understand that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A modeling method for a photolithography negative development process, characterized in that: include: Calibrate the preset photoresist model based on the exposure aerial image and the preset calibration data set to obtain a pre-calibrated photoresist model; Inputting the exposure aerial image into the pre-calibrated photoresist model to obtain a photoresist image, and constructing a negative development shrinkage effect characteristic item based on the exposure aerial image and the photoresist image; The negative development shrinkage effect characteristic item is combined with the pre-calibrated photoresist model to establish a negative development photoresist model.

2. The modeling method for the negative development process of photolithography according to claim 1, characterized in that: The preset calibration data set includes one or more of the following: Key dimension dataset measured after photoresist is exposed by an actual lithography machine; Key profile dataset measured after photoresist exposure on an actual lithography machine; A photoresist image or profile that is produced by exact simulation.

3. The modeling method for the negative development process of photolithography according to claim 1 or 2, characterized in that: The method of performing an initial calibration on a preset photoresist model based on the exposure aerial image and a preset calibration data set to obtain a pre-calibrated photoresist model includes: Inputting the exposure aerial image into a preset photoresist model to obtain first output data; Comparing the first output data with the preset calibration data set to obtain a first comparison result; The coefficients of the preset photoresist model are adjusted based on the first comparison result until the comparison error is minimized.

4. The modeling method for the negative development process of photolithography according to claim 1, characterized in that: The constructing of a negative development shrinkage effect characteristic item based on the exposure aerial image and the photoresist image includes: extracting a photoresist profile of the photoresist image; obtaining a distance distribution image based on the photoresist profile; Based on the distance distribution image, calculating the direction field and constructing the contraction stress function; obtaining a void distribution image based on the exposed aerial image; Obtaining a displacement distribution caused by a shrinkage effect based on the shrinkage stress function and the void distribution image; Calculating a gradient image of the photoresist image based on the pre-calibrated photoresist model; The negative development shrinkage effect characteristic item is obtained based on the displacement caused by the shrinkage effect and the gradient image of the photoresist image.

5. The modeling method for the negative development process of photolithography according to claim 4, characterized in that: The obtaining of a distance distribution image based on the photoresist profile includes any one of the following: Based on the photoresist profile, a distance distribution image is obtained by a rapid scanning method; Based on the photoresist profile, a distance distribution image is obtained by a level set method; Based on the photoresist profile, a distance distribution image is obtained by a rasterization method.

6. The modeling method for the negative development process of photolithography according to claim 4, characterized in that: The calculating the direction field and constructing the contraction stress function based on the distance distribution image includes: Calculating the partial derivatives of the distance distribution image in the x and y directions as the direction field; Setting a stress characteristic function, wherein the stress characteristic function is used to describe the relationship between the stress and distance of the gap generated by gas evaporation in the post-baking process to the surrounding position; A shrinkage stress function is constructed based on the stress characteristic function and the distance distribution image.

7. The modeling method for the negative development process of photolithography according to claim 4, characterized in that: The step of obtaining a void distribution image based on the exposed aerial image includes: Inputting the exposure aerial image into a post-exposure baking PEB model to obtain a void distribution image output by the PEB model; or Constructing the relationship between the exposure aerial image and the void distribution image by using an exponential function to obtain the void distribution image; or, The relationship between the exposure aerial image and the void distribution image is approximately characterized by a Sigmoid function to obtain the void distribution image.

8. The modeling and labeling method for the photolithography negative development process according to claim 4, characterized in that: The obtaining of the displacement caused by the shrinkage effect based on the shrinkage stress function and the void distribution image includes: The shrinkage stress function is convolved with the void distribution image to calculate the displacement caused by the shrinkage effect.

9. The modeling method for the negative development process of photolithography according to claim 1, characterized in that: The step of combining the negative development shrinkage effect characteristic item with the pre-calibrated photoresist model to establish a negative development photoresist model includes: One or more negative development shrinkage effect characteristic terms are linearly combined or rationally combined with the pre-calibrated photoresist model.

10. A calibration method for a photolithography negative development process, characterized in that: The modeling method used in the negative development process of photolithography according to claim 1 comprises: Calibrate the preset photoresist model based on the exposure aerial image and the preset calibration data set to obtain the preset photoresist model calibration result parameters; inputting the exposure aerial image into a negative development photoresist model to obtain second output data; Comparing the second output data with the preset calibration data set to obtain a second comparison result; Adjusting the coefficients of the negative development photoresist model based on the second comparison result until the comparison error is minimized, thereby obtaining a characteristic item parameter of the negative development shrinkage effect; All parameters of the negative development photoresist model are jointly calibrated based on the initial results of the preset photoresist model calibration result parameters and the initial results of the negative development shrinkage effect characteristic item parameters to obtain a calibrated negative development photoresist model.

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