A method and apparatus for simulating photolithography
By constructing the elastic mechanical equation of photoresist and solving it using the finite element method, the post-baking and development process of negative photoresist was simulated, solving the problem of negative photoresist shrinkage in photolithography simulation and improving the accuracy of photolithography simulation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DONGFANG JINGYUAN ELECTRON LTD
- Filing Date
- 2023-05-15
- Publication Date
- 2026-06-05
AI Technical Summary
Existing technologies cannot effectively simulate the shrinkage phenomenon of negative photoresist during the photolithography process, resulting in insufficient accuracy in photolithography simulation.
By acquiring simulation parameters, and based on optical, post-baking, and etching parameters, the elastic mechanical equation of the photoresist is constructed. The equilibrium equation is solved using the finite element method to determine the inhibitor concentration distribution information of the negative photoresist. The post-baking and development process of the photoresist is simulated to generate the 3D morphology of the photoresist.
This improves the accuracy of photolithography simulation, accurately simulating the shrinkage and deformation of negative photoresist during the post-baking process, ensuring the accuracy of the height, width, and sidewall angle of the photoresist after development, and improving the accuracy of the morphology simulation after etching.
Smart Images
Figure CN116627002B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of photolithography simulation technology, and in particular to a photolithography simulation method and apparatus. Background Technology
[0002] Photolithography is a fundamental process in the manufacturing of circuit structures for electronic devices. With the development of electronic technology, structures with nanoscale feature sizes have gradually become the mainstream trend in semiconductor device manufacturing, making photolithography increasingly complex. Photolithography simulation, as a layout design tool, can assist semiconductor engineers in simulating the photolithography process, designing process windows, further shortening development cycles, and improving product quality.
[0003] In traditional photolithography development processes, positive development is typically used, where the exposed positive photoresist areas are dissolved in the developer, thus preserving the unexposed areas. In recent years, to improve development resolution, negative tone development (NTD) techniques have emerged, which use negative photoresist to preserve the exposed areas. However, in photolithography simulation, traditional positive development systems cannot simulate phenomena such as shrinkage that occur with negative photoresist during the photolithography process.
[0004] In view of this, this application is made to at least partially solve the technical problems existing in the prior art. Summary of the Invention
[0005] This application provides a data detection method and apparatus to solve the problem that the prior art cannot simulate the shrinkage phenomenon that occurs in negative photoresist during the photolithography process.
[0006] According to a first aspect of this application, a photolithography simulation method is provided, the simulation method comprising:
[0007] Obtain simulation parameters, including optical parameters, post-bake parameters, and etching parameters;
[0008] Based on optical parameters, the photoresist set on the substrate is exposed to obtain the photoacid distribution information in the photoresist.
[0009] Based on the post-baking parameters, the photoresist after exposure is post-baked, and based on the photoacid distribution information, the initial distribution information of the inhibitor concentration in the initial state is obtained.
[0010] When the photoresist is a negative photoresist, the inhibitor concentration distribution information in the equilibrium state is determined based on the inhibitor concentration distribution information in the initial state.
[0011] The photoresist is developed, and the first 3D morphology of the photoresist is generated based on the inhibitor concentration distribution information under equilibrium conditions.
[0012] Based on the first 3D morphology and etching parameters, the photoresist is etched to obtain the etched photoresist and the second 3D morphology of the substrate.
[0013] Preferably, when the photoresist is a negative photoresist, determining the inhibitor concentration distribution information in the equilibrium state based on the inhibitor concentration distribution information in the initial state includes:
[0014] Based on the inhibitor concentration distribution information under the initial state, the elastic mechanical equation of the photoresist is constructed; based on the elastic mechanical equation of the photoresist, the equilibrium equation is constructed; based on the finite element method, the equilibrium equation is solved to obtain the inhibitor concentration distribution information under the equilibrium state.
[0015] Preferably, based on the inhibitor concentration distribution information in the initial state, the elastic mechanical equation of the photoresist is constructed, including:
[0016] Based on the inhibitor concentration distribution information under the initial state, a mathematical model s between the inhibitor concentration and deformation of the photoresist is constructed; the stiffness matrix [D] and elastic strain ε of the photoresist are determined; based on s, [D] and ε, the elastic mechanical equation of the photoresist is constructed as: σ=[D](ε+s).
[0017] Preferably, based on the elasticity equations of photoresist, an equilibrium equation is constructed, including: obtaining the first equilibrium equation in the X direction based on the elasticity equations. Based on the equations of elasticity, the first equilibrium equation in the Y direction is obtained. Based on the equations of elasticity, the first equilibrium equation in the Z direction is obtained.
[0018] Preferably, based on the finite element method, the equilibrium equation is solved to obtain the inhibitor concentration distribution information under equilibrium conditions, including:
[0019] The solution interval is divided, and the equilibrium equation is solved to obtain the inhibitor concentration change distribution information. Based on the inhibitor concentration change distribution information and the inhibitor concentration distribution information under the initial state, the inhibitor concentration distribution information under the equilibrium state is obtained.
[0020] Preferably, the solution interval is divided, the equilibrium equation is solved, and the information on the distribution of inhibitor concentration changes is obtained, including:
[0021] Divide the solution interval; determine the element stiffness matrix based on the solution interval; construct a linear system of equilibrium equations based on the element stiffness matrix; solve the linear system of equations according to the boundary conditions of the equilibrium equations to obtain the information on the distribution of inhibitor concentration changes.
[0022] Preferably, based on the boundary conditions of the equilibrium equations, the linear equation system is solved to obtain information on the distribution of inhibitor concentration changes, including:
[0023] If the error of the solution to the equilibrium equation meets the preset conditions, the solution to the equilibrium equation is the information on the distribution of inhibitor concentration changes; if the error of the solution to the equilibrium equation does not meet the preset conditions, return to the step of dividing the solution interval until the error of the solution to the equilibrium equation meets the preset conditions, and obtain the information on the distribution of inhibitor concentration changes.
[0024] Preferably, the boundary conditions of the equilibrium equation include a first type of boundary condition and a second type of boundary condition; the first type of boundary condition is that the displacement at the connection between the photoresist and the substrate is 0, and the second type of boundary condition is the force value on the upper surface generated by the initial deformation of the photoresist.
[0025] According to a second aspect of the present invention, a photolithography simulation apparatus is provided, the simulation apparatus comprising:
[0026] The acquisition module is used to acquire simulation parameters, including optical parameters, post-baking parameters, and etching parameters.
[0027] The exposure module is used to expose the photoresist on the substrate based on optical parameters to obtain the photoacid distribution information in the photoresist;
[0028] The first post-bake module is used to perform post-bake processing on the photoresist after exposure based on post-bake parameters, and to obtain the initial distribution information of inhibitor concentration in the initial state based on photoacid distribution information.
[0029] The second post-baking module is used to determine the inhibitor concentration distribution information in the equilibrium state based on the inhibitor concentration distribution information in the initial state when the photoresist is a negative photoresist.
[0030] The developing module is used to develop the photoresist and generate the first 3D morphology of the photoresist based on the inhibitor concentration distribution information under equilibrium conditions.
[0031] The etching module is used to etch the photoresist based on the first 3D morphology and etching parameters to obtain the etched photoresist and the second 3D morphology of the substrate.
[0032] Preferably, the second post-baking module includes:
[0033] The first building module is used to construct the elastic mechanical equation of the photoresist based on the inhibitor concentration distribution information in the initial state;
[0034] The second building module is used to construct the equilibrium equation based on the elastic mechanical equation of photoresist;
[0035] The solver module is used to solve the equilibrium equations based on the finite element method to obtain the inhibitor concentration distribution information under equilibrium conditions.
[0036] Preferably, the first building module is used for:
[0037] Based on the inhibitor concentration distribution information under the initial state, a mathematical model s between the inhibitor concentration and deformation of the photoresist is constructed; the stiffness matrix [D] and elastic strain ε of the photoresist are determined; based on s, [D] and ε, the elastic mechanical equation of the photoresist is constructed as: σ=[D](ε+s).
[0038] Preferably, the second building module is used for:
[0039] Based on the equations of elasticity, the first equilibrium equation in the X direction is obtained. Based on the equations of elasticity, the first equilibrium equation in the Y direction is obtained. Based on the equations of elasticity, the first equilibrium equation in the Z direction is obtained.
[0040] Preferably, the solver module is used for:
[0041] The solution interval is divided, and the equilibrium equation is solved to obtain the inhibitor concentration change distribution information. Based on the inhibitor concentration change distribution information and the inhibitor concentration distribution information under the initial state, the inhibitor concentration distribution information under the equilibrium state is obtained.
[0042] Preferably, the solver module is also used for:
[0043] Divide the solution interval; determine the element stiffness matrix based on the solution interval; construct a linear system of equilibrium equations based on the element stiffness matrix; solve the linear system of equations according to the boundary conditions of the equilibrium equations to obtain the information on the distribution of inhibitor concentration changes.
[0044] Preferably, the solver module is also used for:
[0045] If the error of the solution to the equilibrium equation meets the preset conditions, the solution to the equilibrium equation is the information on the distribution of inhibitor concentration changes; if the error of the solution to the equilibrium equation does not meet the preset conditions, return to the step of dividing the solution interval until the error of the solution to the equilibrium equation meets the preset conditions, and obtain the information on the distribution of inhibitor concentration changes.
[0046] Preferably, the boundary conditions of the equilibrium equation include a first type of boundary condition and a second type of boundary condition; the first type of boundary condition is that the displacement at the connection between the photoresist and the substrate is 0, and the second type of boundary condition is the force value on the upper surface generated by the initial deformation of the photoresist.
[0047] According to a third aspect of the present invention, an electronic device is provided, comprising: a processor and a memory storing computer program instructions;
[0048] The processor implements any of the above-mentioned photolithography simulation methods when executing computer program instructions.
[0049] According to a fourth aspect of the present invention, a computer-readable storage medium is provided, on which computer program instructions are stored, which, when executed by a processor, implement any of the above-described photolithography simulation methods.
[0050] In summary, the photolithography simulation method and apparatus provided in this application have at least the following beneficial effects:
[0051] The photolithography simulation method of this application includes: acquiring simulation parameters, wherein the simulation parameters include optical parameters, post-baking parameters, and etching parameters; based on the optical parameters, performing exposure processing on the photoresist disposed on the substrate to obtain photoacid distribution information in the photoresist; based on the post-baking parameters, performing post-baking processing on the exposed photoresist, and obtaining initial inhibitor concentration distribution information in the initial state based on the photoacid distribution information; in the case of a negative photoresist, determining the inhibitor concentration distribution information in the equilibrium state based on the inhibitor concentration distribution information in the initial state; performing development processing on the photoresist, and generating a first 3D morphology of the photoresist based on the inhibitor concentration distribution information in the equilibrium state; and etching the photoresist based on the first 3D morphology and etching parameters to obtain the etched photoresist and a second 3D morphology of the substrate. By accurately simulating the shrinkage deformation generated by the negative photoresist during the post-baking process, the simulation accuracy of photolithography can be greatly improved. Attached Figure Description
[0052] To more clearly illustrate the specific embodiments of this application or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0053] Figure 1 A flowchart illustrating a photolithography simulation method provided for embodiments of this application;
[0054] Figure 2 A flowchart illustrating a photolithography simulation method provided for embodiments of this application;
[0055] Figure 3 A schematic diagram of the exposure process provided for an embodiment of this application;
[0056] Figure 4 An image showing the effect of exposure provided for an embodiment of this application;
[0057] Figure 5 Post-baking effect diagram provided for embodiments of this application;
[0058] Figure 6 A development effect diagram provided for an embodiment of this application;
[0059] Figure 7 A flowchart illustrating a photolithography simulation method provided for embodiments of this application;
[0060] Figure 8 A schematic diagram of the subdivided solution intervals provided for embodiments of this application;
[0061] Figure 9 A structural diagram of a photolithography simulation apparatus provided for embodiments of this application;
[0062] Figure 10 This is a structural diagram of an electronic device provided as an embodiment of the present application. Detailed Implementation
[0063] To make the above and other features and advantages of this application clearer, the application is further described below with reference to the accompanying drawings. It should be understood that the specific embodiments given herein are for the purpose of explanation to those skilled in the art, and are exemplary only, not restrictive.
[0064] In the following description, numerous specific details are set forth to provide a thorough understanding of this application. However, it will be apparent to those skilled in the art that the specific details are not required to practice this application. In other instances, well-known steps or operations have not been described in detail to avoid obscuring this application.
[0065] The lithography simulation method provided in this application embodiment can be executed by the lithography simulation device provided in this application embodiment, which can be configured in an electronic device.
[0066] refer to Figure 1 , Figure 2 A simulation method for photolithography, the simulation method comprising:
[0067] S110, obtain simulation parameters, including optical parameters, post-baking parameters, and etching parameters.
[0068] Among them, optical parameters may include information such as the wavelength and intensity of light during the simulated exposure process; post-baking parameters may include information such as the post-baking time and temperature during the simulated post-baking process; and etching parameters may include information such as the composition of the etchant or etching gas, etching temperature, and etching time during the etching process.
[0069] S120, based on optical parameters, exposes the photoresist placed on the substrate to obtain the photoacid distribution information in the photoresist.
[0070] refer to Figure 3 , Figure 4 This step simulates the exposure process of photolithography. Based on optical parameters, it simulates the interaction between incident light and photoacid generators in the photoresist, resulting in a photochemical reaction that produces photoacids in the exposed area.
[0071] S130, based on the post-baking parameters, performs post-baking on the photoresist after exposure, and obtains the initial distribution information of the inhibitor concentration in the initial state based on the photoacid distribution information;
[0072] S140, when the photoresist is a negative photoresist, determine the inhibitor concentration distribution information in the equilibrium state based on the inhibitor concentration distribution information in the initial state.
[0073] refer to Figure 5 , Figure 6 Based on the post-baking parameters, the post-baking process of photolithography is simulated. During the post-baking process, due to the acid-catalyzed deprotection reaction, the volatile products generated by the reaction between photoacid and inhibitor will gradually evaporate, resulting in shrinkage of the photoresist. Therefore, in this application, the initial distribution information of inhibitor concentration is first calculated based on the photoacid distribution information.
[0074] In the subsequent development step, if positive photoresist is used, the exposed portion of the photoresist will be removed, and the shrinkage that occurs during post-baking will not affect the subsequent development results. However, if negative photoresist is used, the exposed portion of the photoresist will be retained. Therefore, shrinkage during post-baking will affect not only the height of the photoresist but also the width of critical measurement locations, corner angles, etc., during development.
[0075] Therefore, this application takes into account the shrinkage of the photoresist during the post-baking process. First, based on the photoacid distribution information, the initial inhibitor concentration distribution information in the initial state is obtained. Then, based on the inhibitor concentration distribution information in the initial state, the inhibitor concentration distribution information in the equilibrium state is determined. The equilibrium state refers to the state of the photoresist area after shrinkage and deformation during the post-baking process. This allows for the obtaining of the true morphology of the exposed portion of the photoresist after post-baking and development, improving the simulation accuracy of the negative development process and thus enhancing the simulation precision of photolithography.
[0076] S150, the photoresist is developed, and the first 3D morphology of the photoresist is generated based on the inhibitor concentration distribution information under equilibrium conditions.
[0077] S160, based on the first 3D morphology and etching parameters, the photoresist is etched to obtain the etched photoresist and the second 3D morphology of the substrate.
[0078] After obtaining the true morphology of the exposed portion of the photoresist after the post-baking process, the first 3D morphology of the photoresist can be generated after development based on the inhibitor concentration distribution information under equilibrium conditions. This is the true morphology of the photoresist retained after exposure, post-baking, and development. Therefore, after simulating the etching process based on etching parameters, the morphology of the photoresist and substrate can be accurately obtained, i.e., the second 3D morphology of the photoresist and substrate.
[0079] In summary, the simulation method provided in this application can accurately simulate the shrinkage deformation of negative photoresist during the post-baking process, and accurately simulate the height, width, and edge corner angle of the remaining photoresist after post-baking and development. Thus, it can accurately simulate the morphology of the etched substrate and photoresist, greatly improving the simulation accuracy of photolithography.
[0080] Reference Figure 7 In some implementations, S140 is specifically implemented in the following ways:
[0081] S1401, based on the inhibitor concentration distribution information in the initial state, construct the elastic mechanical equation of the photoresist.
[0082] In this scheme, photoresist is regarded as a solid elastic material. The shrinkage of photoresist caused by post-baking during negative development is regarded as an initial deformation, that is, the deformation that cannot be recovered after the removal of external force. Therefore, according to Hooke's law, the linear elastic mechanical equation of photoresist can be constructed: σ=[D](ε+s), where σ is the elastic stress of photoresist, [D] is the stiffness matrix (composed of Young's modulus and Poisson's ratio of photoresist), ε is the elastic strain of photoresist, and s is the mathematical model of the initial deformation of photoresist during post-baking, which is used to characterize the correspondence between the inhibitor concentration of photoresist and the deformation.
[0083] S1402, based on the elasticity equation of photoresist, construct the equilibrium equation.
[0084] After constructing the equations of elasticity, differentiating them in the x, y, and z directions yields the equilibrium equations in the x, y, and z directions. as well as
[0085] S1403, based on the finite element method, solves the equilibrium equation to obtain the inhibitor concentration distribution information under equilibrium conditions.
[0086] This application employs the finite element method, divides the solution interval, solves the equilibrium equation, and obtains the inhibitor concentration change distribution information. Based on this information and the initial state inhibitor concentration distribution information, the equilibrium state inhibitor concentration distribution information is then derived. (Reference) Figure 8 Specifically, the solution interval is subdivided to form the element stiffness matrix. The overall stiffness matrix is then combined, the boundary conditions are handled, and a large system of linear equations is solved. If the error of the solution to the system of equations does not meet the conditions, the interval is further subdivided, and the above steps are repeated until the solution to the system of equations meets the conditions, thus obtaining the numerical solution of the equilibrium equation, which is the information on the distribution of inhibitor concentration changes.
[0087] It should be noted that the mathematical model 's' of the initial deformation can characterize the relationship between the inhibitor concentration and the deformation of the photoresist. Therefore, by solving the equilibrium equation, the displacement of the photoresist at each point in three-dimensional space can be obtained, thereby obtaining the inhibitor concentration distribution information. Furthermore, based on the inhibitor concentration distribution information and the inhibitor concentration distribution information in the initial state, the inhibitor concentration distribution information in the equilibrium state can be obtained, which means the inhibitor concentration distribution information of the photoresist after post-baking can be obtained.
[0088] In addition, the known conditions for solving the equilibrium equations include the first type of boundary condition (the bottom layer displacement is 0) and the second type of boundary condition (the upper surface is subjected to force due to the initial deformation). Since the photoresist is fixed on the substrate (the material is usually glass, silicon, etc.), we assume that there will be no displacement at the junction of the photoresist and the substrate, that is, at the lowest layer of the photoresist.
[0089] Compared with other methods for solving differential equations, such as the finite difference method and the conjugate gradient method, the finite element method used in this application has a faster convergence speed and higher computational accuracy.
[0090] Reference Figure 9 This application provides a photolithography simulation apparatus, which includes:
[0091] The acquisition module 901 is used to acquire simulation parameters, including optical parameters, post-baking parameters, and etching parameters.
[0092] The exposure module 902 is used to expose the photoresist disposed on the substrate based on the optical parameters to obtain the photoacid distribution information in the photoresist;
[0093] The first post-bake module 903 is used to perform post-bake processing on the photoresist after exposure based on the post-bake parameters, and to obtain the initial distribution information of the inhibitor concentration in the initial state based on the photoacid distribution information.
[0094] The second post-baking module 904 is used to determine the inhibitor concentration distribution information in the equilibrium state based on the inhibitor concentration distribution information in the initial state when the photoresist is a negative photoresist.
[0095] The developing module 905 is used to develop the photoresist and generate the first 3D morphology of the photoresist based on the inhibitor concentration distribution information under equilibrium conditions.
[0096] Etching module 906 is used to etch the photoresist based on the first 3D morphology and the etching parameters to obtain the etched photoresist and the second 3D morphology of the substrate.
[0097] In some implementations, the second post-baking module includes:
[0098] The first building module is used to construct the elastic mechanical equation of the photoresist based on the inhibitor concentration distribution information in the initial state;
[0099] The second building module is used to construct the equilibrium equation based on the elastic mechanical equation of photoresist;
[0100] The solver module is used to solve the equilibrium equations based on the finite element method to obtain the inhibitor concentration distribution information under equilibrium conditions.
[0101] In some implementations, the first building module is used for:
[0102] Based on the inhibitor concentration distribution information under the initial state, a mathematical model s between the inhibitor concentration and deformation of the photoresist is constructed; the stiffness matrix [D] and elastic strain ε of the photoresist are determined; based on s, [D] and ε, the elastic mechanical equation of the photoresist is constructed as: σ=[D](ε+s).
[0103] In some implementations, the second building module is used for:
[0104] Based on the equations of elasticity, the first equilibrium equation in the X direction is obtained. Based on the equations of elasticity, the first equilibrium equation in the Y direction is obtained. Based on the equations of elasticity, the first equilibrium equation in the Z direction is obtained.
[0105] In some implementations, the solver module is used for:
[0106] The solution interval is divided, and the equilibrium equation is solved to obtain the inhibitor concentration change distribution information. Based on the inhibitor concentration change distribution information and the inhibitor concentration distribution information under the initial state, the inhibitor concentration distribution information under the equilibrium state is obtained.
[0107] In some implementations, the solver module is also used for:
[0108] Divide the solution interval; determine the element stiffness matrix based on the solution interval; construct a linear system of equilibrium equations based on the element stiffness matrix; solve the linear system of equations according to the boundary conditions of the equilibrium equations to obtain the information on the distribution of inhibitor concentration changes.
[0109] In some implementations, the solver module is also used for:
[0110] If the error of the solution to the equilibrium equation meets the preset conditions, the solution to the equilibrium equation is the information on the distribution of inhibitor concentration changes; if the error of the solution to the equilibrium equation does not meet the preset conditions, return to the step of dividing the solution interval until the error of the solution to the equilibrium equation meets the preset conditions, and obtain the information on the distribution of inhibitor concentration changes.
[0111] The simulation apparatus provided in this application can accurately simulate the shrinkage and deformation of negative photoresist during post-baking, and accurately simulate the morphology, width, and edge corner angles of the remaining photoresist after post-baking and development. This allows for accurate simulation of the etched substrate and photoresist morphology, significantly improving the simulation accuracy of the photolithography system. Furthermore, the use of the mature finite element method ensures both computational speed and accuracy. This shortens the simulation process and provides a more effective feedforward simulation tool for photolithography.
[0112] It should be understood that the specific features, operations, and details described herein with respect to the methods of this application can also be similarly applied to the apparatus and system of this application, or vice versa. Furthermore, each step of the methods of this application described above can be performed by a corresponding component or unit of the apparatus or system of this application.
[0113] It should be understood that the various modules / units of the device of this application can be implemented wholly or partially through software, hardware, firmware, or a combination thereof. Each module / unit can be embedded in the processor of the electronic device in hardware or firmware form or independent of the processor, or it can be stored in the memory of the electronic device in software form for the processor to call to execute the operation of each module / unit. Each module / unit can be implemented as an independent component or module, or two or more modules / units can be implemented as a single component or module.
[0114] like Figure 10 As shown, this application provides an electronic device 1000, which includes a processor 1001 and a memory 1002 storing computer program instructions. The processor 1001 executes the computer program instructions to implement the steps of the aforementioned photolithography simulation method. This electronic device 1000 can be broadly categorized as a server, terminal, or any other electronic device with the necessary computing and / or processing capabilities.
[0115] In one embodiment, the electronic device 1000 may include a processor, memory, network interface, communication interface, etc., connected via a system bus. The processor of the electronic device 1000 can be used to provide necessary computing, processing, and / or control capabilities. The memory of the electronic device 1000 may include non-volatile storage media and internal memory. The non-volatile storage media may store an operating system, computer programs, etc. The internal memory can provide an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface and communication interface of the electronic device 1000 can be used to connect and communicate with external devices via a network. When the computer program is executed by the processor, it performs the steps of the method of this application.
[0116] This application provides a computer-readable storage medium storing computer program instructions, which, when executed by a processor, implement the above-described photolithography simulation method.
[0117] Those skilled in the art will understand that the method steps of this application can be performed by a computer program instructing related hardware, such as electronic device 1000 or a processor. The computer program can be stored in a non-transitory computer-readable storage medium, and its execution causes the steps of this application to be performed. Depending on the context, any reference herein to memory, storage, or other media may include non-volatile or volatile memory. Examples of non-volatile memory include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid-state drive, etc. Examples of volatile memory include random access memory (RAM), external cache memory, etc.
[0118] The technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification, provided that such combination does not contain contradictions.
[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A method for simulating photolithography, characterized in that, The simulation method includes: Obtain simulation parameters, including optical parameters, post-baking parameters, and etching parameters; Based on the optical parameters, the photoresist disposed on the substrate is exposed to obtain the photoacid distribution information in the photoresist. Based on the post-baking parameters, the photoresist after exposure is post-baked, and based on the photoacid distribution information, the initial distribution information of the inhibitor concentration in the initial state is obtained. When the photoresist is a negative photoresist, the inhibitor concentration distribution information in the equilibrium state is determined based on the inhibitor concentration distribution information in the initial state. The photoresist is developed, and a first 3D morphology of the photoresist is generated based on the inhibitor concentration distribution information under equilibrium conditions. Based on the first 3D morphology and the etching parameters, the photoresist is etched to obtain the etched photoresist and the second 3D morphology of the substrate. When the photoresist is a negative photoresist, determining the inhibitor concentration distribution information in the equilibrium state based on the inhibitor concentration distribution information in the initial state includes: Based on the inhibitor concentration distribution information in the initial state, the elastic mechanical equation of the photoresist is constructed; Based on the elasticity equation of the photoresist, an equilibrium equation is constructed; Based on the finite element method, the equilibrium equation is solved to obtain the inhibitor concentration distribution information under equilibrium conditions; the equilibrium state is the state of the area exposed by the photoresist after shrinkage and deformation caused by post-baking treatment.
2. The photolithography simulation method according to claim 1, characterized in that, The elastic mechanical equation of the photoresist is constructed based on the inhibitor concentration distribution information in the initial state, including: Based on the inhibitor concentration distribution information under the initial state, a mathematical model is constructed to determine the relationship between the inhibitor concentration and deformation of the photoresist. ; Determine the stiffness matrix of the photoresist and elastic strain ; based on , and The elastic mechanical equation of the photoresist is constructed as follows: .
3. The photolithography simulation method according to claim 2, characterized in that, The equilibrium equation is constructed based on the elastic mechanical equation of the photoresist, including: Based on the aforementioned elasticity equations, the first equilibrium equation in the X direction is obtained. ; Based on the aforementioned elasticity equations, the first equilibrium equation in the Y direction is obtained. ; Based on the aforementioned elasticity equations, the first equilibrium equation in the Z direction is obtained. .
4. The photolithography simulation method according to claim 3, characterized in that, The process of solving the equilibrium equation using the finite element method to obtain the inhibitor concentration distribution information under equilibrium conditions includes: Divide the solution interval, solve the equilibrium equation, and obtain the distribution information of inhibitor concentration changes; Based on the inhibitor concentration change distribution information and the inhibitor concentration distribution information under the initial state, the inhibitor concentration distribution information under the equilibrium state is obtained.
5. The photolithography simulation method according to claim 4, characterized in that, The process of dividing the solution interval and solving the equilibrium equation yields information on the distribution of inhibitor concentration changes, including: Divide the solution interval; Determine the element stiffness matrix based on the solution interval; Based on the element stiffness matrix, a system of linear equations is constructed for the equilibrium equations; Based on the boundary conditions of the equilibrium equation, the linear equation system is solved to obtain the distribution information of inhibitor concentration changes.
6. The photolithography simulation method according to claim 5, characterized in that, The step of solving the linear equation system based on the boundary conditions of the equilibrium equation to obtain the inhibitor concentration change distribution information includes: If the error of the solution to the equilibrium equation meets the preset conditions, the solution to the equilibrium equation is the information on the distribution of inhibitor concentration changes. If the error of the solution to the equilibrium equation does not meet the preset conditions, return to the step of dividing the solution interval until the error of the solution to the equilibrium equation meets the preset conditions, and obtain the inhibitor concentration change distribution information.
7. A photolithography simulation device, characterized in that, The simulation device includes: An acquisition module is used to acquire simulation parameters, wherein the simulation parameters include optical parameters, post-baking parameters, and etching parameters; An exposure module is used to expose a photoresist disposed on a substrate based on the optical parameters to obtain photoacid distribution information in the photoresist. The first post-bake module is used to perform post-bake processing on the photoresist after exposure based on the post-bake parameters, and to obtain the initial distribution information of the inhibitor concentration in the initial state based on the photoacid distribution information. The second post-baking module is used to determine the inhibitor concentration distribution information in the equilibrium state based on the inhibitor concentration distribution information in the initial state when the photoresist is a negative photoresist. The developing module is used to develop the photoresist and generate the first 3D morphology of the photoresist based on the inhibitor concentration distribution information under equilibrium conditions. An etching module is used to etch the photoresist based on the first 3D morphology and the etching parameters to obtain the etched photoresist and the second 3D morphology of the substrate. The second post-drying module includes: The first building module is used to construct the elastic mechanical equation of the photoresist based on the inhibitor concentration distribution information in the initial state; The second building module is used to construct the equilibrium equation based on the elastic mechanical equation of photoresist; The solution module is used to solve the equilibrium equation based on the finite element method to obtain the inhibitor concentration distribution information under equilibrium conditions; the equilibrium state is the state of the area exposed by the photoresist after shrinkage and deformation caused by post-baking treatment.
8. An electronic device, characterized in that, The electronic device includes: a processor and a memory storing computer program instructions; When the processor executes the computer program instructions, it implements the lithography simulation method as described in any one of claims 1-6.
9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer program instructions, which, when executed by a processor, implement the lithography simulation method as described in any one of claims 1-6.