Photolithography development simulation method, computer program product and computer device

Abstract

This invention provides a method, computer program, and computer equipment for simulating the development of photoresist. The method includes: determining the computational region where the initial photoresist to be developed is located; discretizing the computational region to generate a grid set composed of multiple grid points; selecting grid points located outside the initial photoresist from the grid set, and constructing a starting point set from these selected grid points; calculating the arrival time of the developer at each grid point within the starting point set; designating each grid point within the starting point set as a known grid point; iteratively determining the arrival time of the developer at the remaining grid points based on their adjacency relationships, and designating the grid points after iteration as known grid points; and determining the morphological changes of the initial photoresist during the development process based on the arrival time of the developer at each known grid point. The advantages of this invention are accurate characterization of the initial morphology of the photoresist and improved accuracy of the development simulation.

Description

Technical Field

[0001] This invention relates to the field of photolithography simulation technology, and in particular to a photoresist development simulation method, computer program product, and computer equipment. Background Technology

[0002] In the simulation calculation of the photoresist development process, it is usually necessary to discretize the spatial region where the photoresist is located and construct a computational model in the form of a grid. At the beginning of the simulation, it is necessary to determine the initial propagation position of the developer and then calculate the progression of the development interface over time based on this, ultimately reconstructing the morphological changes of the photoresist. However, existing photoresist development simulation methods are difficult to accurately characterize the initial morphology of the photoresist, resulting in poor accuracy in the development simulation. Summary of the Invention

[0003] One object of the present invention is to overcome at least one technical defect in the prior art and to provide a method for simulating the development of photoresist, a computer program product, and a computer device.

[0004] A further objective of this invention is to accurately characterize the initial morphology of the photoresist and improve the accuracy of development simulation.

[0005] Another further objective of this invention is to eliminate jagged artifacts caused by the mismatch between grid discretization and the real surface, thereby avoiding the impact of jagged artifacts propagating along the grid on computational accuracy.

[0006] Another further objective of this invention is to achieve a complete simulation of the wavefront propagation of the developer solution, avoiding wavefront backpropagation and computational oscillation.

[0007] Specifically, according to a first aspect of the present invention, the present invention provides a method for simulating the development of photoresist, comprising: The computational region where the initial photoresist to be developed is located is determined, and the computational region is discretized to generate a set of grid points consisting of multiple grid points. Grid points located outside the initial photoresist are selected from the grid point set, and the selected grid points are used to construct a starting point set; Calculate the arrival time of the developer at each grid point within the starting point set; Each grid point in the starting point set is recorded as a known grid point. The arrival time of the developer at the remaining grid points is determined iteratively based on the adjacency relationship between the grid points. The grid points after the iteration is completed are recorded as known grid points. Based on the arrival time of the developer at each known grid point, the morphological changes of the initial photoresist during the development process are determined.

[0008] Optionally, the step of selecting grid points located outside the initial photoresist from the grid point set includes: Obtain the signed distance function of the initial photoresist, wherein the signed distance function satisfies the following: for any grid point in the calculation region, the absolute value of its function value is equal to the shortest distance from the grid point to the surface of the initial photoresist, and the function value is negative when the grid point is located inside the initial photoresist, positive when it is located outside the initial photoresist, and zero when it is located on the surface of the initial photoresist; Select all grid points with positive function values ​​from the grid point set.

[0009] Optionally, the formula for calculating the developer arrival time at each grid point within the starting point set is as follows: ; in, For the grid points in the starting point set The arrival time of the developer solution, For grid points The corresponding symbolic distance function value, For the developer at the grid points The development rate of the photoresist.

[0010] Optionally, the step of iteratively determining the developer arrival time of the remaining grid points based on the adjacency relationship between grid points includes: Based on the developer arrival time of the known grid points, calculate the developer arrival time of the adjacent grid points of each known grid point, and record each adjacent grid point as a grid point to be determined.

[0011] Optionally, the step of calculating the developer arrival time of adjacent grid points of each of the known grid points includes: Based on the developer arrival time of at least one known grid point adjacent to the adjacent grid point, the grid spacing, and the development rate at the adjacent grid point, the process function equation is solved by discretization using a difference scheme to obtain the developer arrival time of the adjacent grid point.

[0012] Optionally, the step of iteratively determining the developer arrival time of the remaining grid points based on the adjacency relationship between grid points further includes: Iteratively execute the process of marking known grid points and updating their neighboring grid points until a preset termination condition is met.

[0013] Optionally, the steps of marking known grid points and updating their neighboring grid points include: Select the grid point with the shortest developer arrival time from the grid points to be determined, and record it as the known grid point; If the adjacent grid points of a known grid point are unknown grid points, calculate the arrival time of the developer and record them as grid points to be determined. If the adjacent grid points of the known grid point are undetermined grid points, recalculate their developer arrival time and update it when the recalculated result is smaller; If the adjacent grid points of a known grid point are also known grid points, no action is taken.

[0014] Optionally, the preset termination condition includes at least one of the following: Each of the undetermined grid points is recorded as a known grid point, the number of iterations reaches the preset maximum number of iterations, and the time for the developer to arrive at the currently selected known grid point is greater than the preset development time threshold.

[0015] According to a second aspect of the present invention, the present invention provides a computer program product comprising a computer program that, when executed by a processor, implements the photoresist development simulation method described in any one of the above descriptions.

[0016] According to a third aspect of the present invention, a computer device is provided, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the photoresist development simulation method described in any one of the above descriptions.

[0017] The photoresist development simulation method of this invention constructs a starting point set by selecting grid points located outside the initial photoresist from the grid point set, and calculates the arrival time of the developer at each grid point within the starting point set, rather than simply setting the arrival time of all external grid points to zero. This method enables the starting point set to accurately reflect the starting position of the developer propagation, avoiding initial morphology characterization deviations caused by coarse assignment, thereby achieving accurate characterization of the initial morphology of the photoresist and improving the accuracy of development simulation.

[0018] Furthermore, the photoresist development simulation method of the present invention employs... The arrival time of the developer at each grid point within the starting set is calculated, ensuring the developer wavefront originates from the continuous surface rather than discrete grid points. This eliminates jagged artifacts caused by the mismatch between grid discretization and the actual surface, preventing the propagation of jagged edges along the grid from affecting computational accuracy. Simultaneously, the signed distance function... It can accurately describe any complex surface, including irregular morphology caused by negative development shrinkage, swelling and other effects. The arrival time of the developer at each grid point in the starting point set is proportional to its distance from the photoresist surface, thus achieving accurate characterization of the initial morphology.

[0019] Furthermore, the photoresist development simulation method of this invention prioritizes processing the undetermined grid points with the shortest arrival time. The developer wavefront propagates outward in increasing time order, conforming to the physical process of the developer gradually advancing from the photoresist surface inward. By calculating and marking unknown grid points as undetermined grid points, the wavefront advance continuously advances outward, and the known grid point region gradually expands until it covers the entire calculation area, completing the full simulation of the developer wavefront propagation. For undetermined grid points, recalculation and optimal updates are allowed in subsequent iterations, ensuring that each grid point ultimately records the minimum arrival time under all possible propagation paths, guaranteeing the global optimality of the results. Known grid points are no longer processed; the grid point state can only change unidirectionally from unknown to undetermined and then back to known, avoiding wavefront backpropagation and calculation oscillations, and ensuring the monotonous convergence of the algorithm.

[0020] The above and other objects, advantages and features of the present invention will become more apparent to those skilled in the art from the following detailed description of specific embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0021] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a flowchart of a photoresist development simulation method according to an embodiment of the present invention; Figure 2 This is a flowchart of marking known grid points and updating their neighboring grid points according to an embodiment of the present invention; Figure 3 This is a flowchart illustrating the process of iteratively determining the developer arrival time of the remaining grid points based on the adjacency relationship between grid points, according to an embodiment of the present invention. Figure 4 This is a schematic diagram of a computer program product according to an embodiment of the present invention; Figure 5 This is a schematic diagram of a computer-readable storage medium according to an embodiment of the present invention; Figure 6 This is a schematic block diagram of a computer device according to an embodiment of the present invention. Detailed Implementation

[0022] Reference will now be made in detail to embodiments of the invention, one or more of which are illustrated in the accompanying drawings. The various embodiments provided are intended to explain the invention and not to limit it. In fact, various modifications and variations to the invention will be apparent to those skilled in the art without departing from the scope or spirit of the invention. For example, a feature illustrated or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, the invention is intended to cover such modifications and variations within the scope of the appended claims and their equivalents.

[0023] In the description of this embodiment, it should be understood that the term "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. When a feature "includes or contains" one or more of the features it covers, unless otherwise specifically described, this indicates that other features are not excluded and may be further included.

[0024] In the description of this embodiment, the terms "one embodiment," "some embodiments," "some examples," "one example," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0025] This invention provides a method for simulating the development of photoresist. Figure 1 This is a flowchart of a photoresist development simulation method according to an embodiment of the present invention, such as... Figure 1 As shown, the photoresist development simulation method includes at least the following steps: Step S101: Determine the computational region where the initial photoresist to be developed is located, and discretize the computational region to generate a set of grid points consisting of multiple grid points. Here, the initial photoresist refers to the photoresist layer that has not yet come into contact with the developer, the computational region is the simulation space range where the photoresist is located, and the discretization process is to divide the continuous space into regular grid units, each grid unit corresponding to a grid point, for subsequent numerical calculations.

[0026] Step S102: Select grid points located outside the initial photoresist from the grid point set, and construct the selected grid points as the starting point set. These external grid points represent the initial locations that the developer can contact, forming the initial boundary for the developer to diffuse into the photoresist.

[0027] Step S103: Calculate the developer arrival time for each grid point within the starting point set. In photoresist development simulation, the developer arrival time refers to the time required for the developer to propagate from the initial contact position to a specific grid point inside the photoresist.

[0028] Step S104: Each grid point within the starting set is designated as a known grid point. Based on the adjacency relationships between grid points, the developer arrival time for the remaining grid points is iteratively determined. The grid points after the iterations are completed are then designated as known grid points. A known grid point is one whose developer arrival time has been calculated and ultimately determined. The developer arrival time of the known grid points is not modified in subsequent iterations, forming a stable basis for the propagated region of the developer wavefront. This step is equivalent to starting from the starting set and, according to the propagation rules between adjacent grid points, sequentially calculating the developer arrival time for each grid point within the entire computational region.

[0029] Step S105: Based on the arrival time of the developer at each known grid point, determine the morphological changes of the initial photoresist during the development process. The earlier the developer arrives at a certain grid point, the earlier the photoresist at that location is dissolved, thus allowing the residual contour of the photoresist to be calculated moment by moment, achieving simulation of the evolution of the developed morphology.

[0030] Using the above method, a starting point set is constructed by selecting grid points located outside the initial photoresist from the grid point set, and the arrival time of the developer at each grid point within the starting point set is calculated, instead of simply setting the arrival time of all external grid points to zero. This method allows the starting point set to accurately reflect the starting position of the developer propagation, avoiding initial morphology characterization deviations caused by coarse assignment, thereby achieving accurate characterization of the initial morphology of the photoresist and improving the accuracy of development simulation.

[0031] In an optional embodiment, when selecting grid points located outside the initial photoresist from the grid point set, the signed distance function of the initial photoresist is first obtained. The signed distance function satisfies the following: for any grid point within the calculation region, the absolute value of its function value is equal to the shortest distance from the grid point to the surface of the initial photoresist, and the function value is negative when the grid point is inside the initial photoresist, positive when it is outside the initial photoresist, and zero when it is on the surface of the initial photoresist. Therefore, it is only necessary to select all grid points with positive function values ​​from the grid point set.

[0032] Therefore, the aforementioned signed distance function quantifies two attributes of a grid point relative to the photoresist surface using a single numerical value: distance information is given by the absolute value of the function, and position information is given by the sign of the function value. Accordingly, by selecting grid points with positive function values, all grid points outside the initial photoresist can be accurately obtained to construct the starting point set.

[0033] In this embodiment, the formula for calculating the developer arrival time at each grid point within the starting point set is as follows: ; in, Grid points in the starting set The arrival time of the developer solution, The function value of the signed distance function corresponding to grid point x. ， For the developer at the grid points The development rate of the photoresist.

[0034] It should be noted that, in this embodiment, the arrival time of the developer is... Negative values ​​are allowed; this is not negative time in a physical sense, but a mathematical construct used to accurately characterize the positional relationship of the developer wavefront relative to the actual photoresist surface. Specifically: When the grid points are located on the photoresist surface =0, at this time =0 indicates that the wavefront of the developer has just reached that position; When the grid points are located outside the photoresist >0, at this time <0 indicates that the developer already existed at that location before time zero (i.e., when development started). The magnitude of the negative value reflects that the grid point is located outside the photoresist, and the developer can contact it without additional propagation time. When the grid is located inside the photoresist <0, at this time >0 indicates that the wavefront of the developer needs a certain amount of time to propagate from the surface to that location.

[0035] Traditional methods uniformly set the developer arrival time of all external grid points to zero, resulting in a serrated boundary on the initial wavefront aligned with the grid. This application, however, achieves... The developer arrival time for each external grid point is calculated so that these time values ​​vary continuously with the distance from the grid point to the real surface, forming a smooth distance field. A negative developer arrival time reflects this continuous variation, which allows the initial wavefront to accurately correspond to the real photoresist surface, rather than a discrete set of grid points.

[0036] Using the above method, The arrival time of the developer at each grid point within the starting point set is calculated so that the wavefront of the developer originates from the continuous surface rather than from discrete grid points. This eliminates the jagged artifacts caused by the mismatch between grid discretization and the real surface, and avoids the impact of jagged artifacts propagating along the grid on the accuracy of the calculation.

[0037] Furthermore, the symbolic distance function It can accurately describe any complex surface, including irregular morphology caused by negative development shrinkage, swelling and other effects. The arrival time of the developer at each grid point in the starting point set is proportional to its distance from the photoresist surface, thus achieving accurate characterization of the initial morphology.

[0038] In an optional embodiment, the step of iteratively determining the developer arrival time of the remaining grid points based on the adjacency relationship between grid points includes: calculating the developer arrival time of adjacent grid points of each known grid point based on the developer arrival time of the known grid points, and recording each adjacent grid point as a grid point to be determined.

[0039] Known grid points are those where the arrival time of the developer has been calculated; their time values ​​are fixed and will not change. Adjacent grid points are those that are directly adjacent to the known grid points in space. By using the arrival time of the developer at the known grid points, the arrival time of the developer at the unknown grid points in the surrounding area can be estimated, thus simulating the gradual expansion of the developer wavefront from the propagated area outwards.

[0040] Specifically, the step of calculating the developer arrival time of adjacent grid points of each known grid point includes: based on the developer arrival time of at least one known grid point adjacent to the adjacent grid point, the grid point spacing, and the development rate at the adjacent grid point, the process function equation is solved by discretization using a difference scheme to obtain the developer arrival time of the adjacent grid point.

[0041] The functional equation is the core equation solved by the Fast Marching Method. The Fast Marching Method is an efficient numerical algorithm for solving functional equations, and its equation form is as follows: ; in, Let be any grid point within the computational region, specifically a grid point directly adjacent to a known grid point. For the developer at the grid points The development rate of the photoresist at the location, ∇ T ( x ) represents the time field At grid points The rate of change in space, including the direction and magnitude of the change.

[0042] This equation is a nonlinear partial differential equation, and its physical meaning is: points on the surface follow a given velocity field. Forward propagation. When this method is applied to photoresist development simulation, Indicates the developer at the grid points The development rate at the location corresponds to the dissolution and propagation process on the photoresist surface. The specific solution process for the functional equation is well-known to those skilled in the art and will not be elaborated here.

[0043] In an optional embodiment, the step of iteratively determining the developer arrival time of the remaining grid points based on the adjacency relationship between grid points further includes: iteratively marking known grid points and updating their adjacent grid points until a preset termination condition is met.

[0044] By repeatedly performing the marking and updating operations, the developer wavefront starts from the starting set (known grid points) and expands outward layer by layer in increasing time order, gradually determining the arrival time of the developer at all grid points in the entire computational region. This process is repeated until the termination condition is met, thus obtaining the temporal distribution of the entire field and completely simulating the entire process of the developer wavefront gradually propagating from the photoresist surface inward.

[0045] Figure 2 This is a flowchart of marking known grid points and updating their neighboring grid points according to an embodiment of the present invention, such as... Figure 2 As shown, marking known grid points and updating their neighboring grid points may include the following steps: Step S201: Select the grid point with the shortest arrival time of the developer from the grid points to be determined, and record it as the known grid point.

[0046] Among them, grid points to be determined refer to grid points where the arrival time of the developer has been preliminarily calculated but not yet finalized. Selecting the grid point with the shortest time means prioritizing the location where the developer wavefront arrives first, which conforms to the time sequence of wavefront propagation.

[0047] Step S202: If the adjacent grid points of the known grid point are unknown grid points (i.e., the developer arrival time has not yet been calculated), calculate their developer arrival time and record them as undetermined grid points. In this step, the developer arrival time of adjacent grid points can be obtained by discretizing the functional equation using a difference scheme.

[0048] Step S203: If the adjacent grid points of the known grid point are undetermined grid points (the developer arrival time is known but not yet confirmed), recalculate their developer arrival time and update it when the recalculated result is smaller. In this step, the recalculated developer arrival time can also be obtained by discretizing the functional equation using a difference scheme.

[0049] Step S204: If the adjacent grid points of the known grid point are also known grid points (the arrival time of the developer has been finally confirmed), no further processing is required.

[0050] Using the above method, by always prioritizing the processing of undetermined grid points with the shortest arrival time, the developer wavefront propagates outward in increasing time order, conforming to the physical process of the developer gradually advancing from the photoresist surface inward. By calculating and marking unknown grid points as undetermined grid points, the wavefront advance continuously advances outward, and the known grid point region gradually expands until it covers the entire computational region, completing the full simulation of developer wavefront propagation. For undetermined grid points, recalculation and optimal updates are allowed in subsequent iterations, ensuring that each grid point ultimately records the minimum arrival time under all possible propagation paths, guaranteeing the global optimality of the results. Known grid points are no longer processed; the grid point state can only change unidirectionally from unknown to undetermined and then back to known, avoiding wavefront backpropagation and computational oscillations, and ensuring the monotonous convergence of the algorithm.

[0051] In some alternative embodiments, the preset termination condition includes at least one of the following: Condition 1: All undetermined grid points are recorded as known grid points. At this point, there are no more undetermined grid points in the computational domain, all grid points have obtained a definite developer arrival time, and the iteration process naturally terminates.

[0052] Condition 2: The number of iterations reaches the preset maximum number of iterations. To prevent infinite loops caused by unexpected situations (such as numerical errors leading to non-convergence), a maximum number of iterations can be preset. When the actual number of iterations reaches this threshold, the iteration is forcibly terminated to ensure the execution efficiency of the algorithm.

[0053] Condition 3: The arrival time of the developer at the currently selected known grid point is greater than the preset development time threshold. In practical applications, we often only focus on the morphological changes within a specific time range during the development process. When the wavefront propagation time exceeds the preset development time threshold (i.e., the total development time set by the development process), subsequent wavefront propagation has no practical impact on the simulation results. Therefore, the iteration can be terminated early when the arrival time of the currently selected known grid point exceeds this threshold, thereby avoiding unnecessary calculations and improving simulation efficiency.

[0054] The purpose of setting the above termination conditions is to provide multiple optional termination criteria, so that the iterative algorithm can terminate the calculation in a timely manner while meeting the simulation accuracy requirements, thus balancing the integrity of the simulation and the computational efficiency.

[0055] Figure 3 This is a flowchart illustrating how the arrival time of the developer at other grid points is determined iteratively based on the adjacency relationship between grid points according to an embodiment of the present invention. Figure 3 As shown, determining the developer arrival time for other grid points by iteratively determining the adjacency relationships between grid points can include the following steps: Step S301: Based on the arrival time of the developer at the known grid points, calculate the arrival time of the developer at the adjacent grid points of each known grid point, and record each adjacent grid point as a grid point to be determined.

[0056] Step S302: Select the grid point with the shortest arrival time of the developer from the grid points to be determined, and record it as the known grid point.

[0057] Step S303: If the adjacent grid points of the known grid point are unknown grid points, calculate the arrival time of the developer and record it as a grid point to be determined, and then proceed to step S306.

[0058] Step S304: If the adjacent grid points of the known grid point are undetermined grid points, recalculate their developer arrival time and update it if the recalculated result is smaller, then proceed to step S306.

[0059] Step S305: If the adjacent grid points of the known grid point are also known grid points, no processing is required, and then step S306 is executed.

[0060] Step S306: Determine whether the iteration process has reached the preset termination condition. If yes, proceed to step S307; otherwise, return to step S302.

[0061] Step S307: Stop the iteration process.

[0062] The development simulation method proposed in this application can be regarded as an improvement on the Fast Marching Method. It accurately filters the starting point set by introducing a signed distance function and adopts... The arrival time of the developer at each grid point within the starting point set is calculated, so that the wavefront of the developer originates from a continuous surface, effectively eliminating jagged artifacts and improving simulation accuracy.

[0063] This embodiment also provides a computer program product 41, a computer-readable storage medium 42, and a computer device 43. Figure 4 This is a schematic diagram of a computer program product according to an embodiment of the present invention. Figure 5 This is a schematic diagram of a computer-readable storage medium according to an embodiment of the present invention. Figure 6 This is a schematic block diagram of a computer device according to an embodiment of the present invention.

[0064] Computer program product 41 includes computer program 411, which, when executed by processor 431, implements any of the aforementioned photoresist development simulation methods. Computer-readable storage medium 42 stores the aforementioned computer program 411, which, when executed by processor 431, implements any of the aforementioned photoresist development simulation methods. Computer device 43 may include memory 432, processor 431, and computer program 411 stored in memory 432 and running on processor 431.

[0065] The computer program 411 used to perform the operations of this invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, status setting data, integrated circuit configuration data, or source code or object code written in any combination of one or more programming languages ​​and procedural programming languages.

[0066] Computer program 411 may execute entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, to perform aspects of the invention, electronic circuits including, for example, programmable logic circuits, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs) may execute computer-readable program instructions to personalize the electronic circuits by utilizing state information of computer-readable program instructions.

[0067] For the purposes of this embodiment, computer program product 41 refers to a related product containing computer program 411. Computer-readable storage medium 42 is a tangible device capable of holding and storing computer program 411, and can be any device capable of containing, storing, communicating, propagating, or transmitting computer program 411 for use by or in conjunction with an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable storage medium 42 include: portable computer disks, hard disks, random access memory 432 (RAM), read-only memory 432 (ROM), erasable programmable read-only memory 432 (EPROM or flash memory), static random access memory 432 (SRAM), portable optical disc read-only memory 432 (CD-ROM), digital multifunction disc (DVD), memory stick, floppy disk, mechanical encoding device, and any suitable combination thereof.

[0068] Therefore, those skilled in the art should recognize that although numerous exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the invention. Thus, the scope of the present invention should be understood and construed as covering all such other variations or modifications.

Claims

1. A method for simulating the development of photoresist, comprising: The computational region where the initial photoresist to be developed is located is determined, and the computational region is discretized to generate a set of grid points consisting of multiple grid points. Grid points located outside the initial photoresist are selected from the grid point set, and the selected grid points are used to construct a starting point set; Calculate the arrival time of the developer at each grid point within the starting point set; Each grid point in the starting point set is recorded as a known grid point. The arrival time of the developer at the remaining grid points is determined iteratively based on the adjacency relationship between the grid points. The grid points after the iteration is completed are recorded as known grid points. Based on the arrival time of the developer at each known grid point, the morphological changes of the initial photoresist during the development process are determined.

2. The development simulation method of a photoresist according to claim 1, wherein, The step of selecting grid points located outside the initial photoresist from the grid point set includes: Obtain the signed distance function of the initial photoresist, wherein the signed distance function satisfies the following: for any grid point in the calculation region, the absolute value of its function value is equal to the shortest distance from the grid point to the surface of the initial photoresist, and the function value is negative when the grid point is located inside the initial photoresist, positive when it is located outside the initial photoresist, and zero when it is located on the surface of the initial photoresist; Select all grid points with positive function values ​​from the grid point set.

3. The development simulation method of a photoresist according to claim 2, wherein, The formula for calculating the developer arrival time at each grid point within the starting point set is as follows: ； wherein, is the developer arrival time at the grid point of the set of starting points, is the grid point corresponding function value of the signed distance function ， is the developer rate of the developer at the grid point on the photoresist.

4. The photoresist development simulation method according to claim 1, wherein, The steps for iteratively determining the developer arrival time of the remaining grid points based on the adjacency relationships between grid points include: Based on the developer arrival time of the known grid points, calculate the developer arrival time of the adjacent grid points of each known grid point, and record each adjacent grid point as a grid point to be determined.

5. The photoresist development simulation method according to claim 4, wherein, The steps for calculating the developer arrival time of adjacent grid points for each of the known grid points include: Based on the developer arrival time of at least one known grid point adjacent to the adjacent grid point, the grid spacing, and the development rate at the adjacent grid point, the process function equation is solved by discretization using a difference scheme to obtain the developer arrival time of the adjacent grid point.

6. The photoresist development simulation method according to claim 4, wherein, The steps of iteratively determining the developer arrival time of the remaining grid points based on the adjacency relationships between grid points also include: Iteratively execute the process of marking known grid points and updating their neighboring grid points until a preset termination condition is met.

7. The photoresist development simulation method according to claim 6, wherein, The steps for marking known grid points and updating their neighboring grid points include: Select the grid point with the shortest developer arrival time from the grid points to be determined, and record it as the known grid point; If the adjacent grid points of a known grid point are unknown grid points, calculate the arrival time of the developer and record them as grid points to be determined. If the adjacent grid points of the known grid point are undetermined grid points, recalculate their developer arrival time and update it when the recalculated result is smaller; If the adjacent grid points of a known grid point are also known grid points, no action is taken.

8. The photoresist development simulation method according to claim 7, wherein, The preset termination condition includes at least one of the following: Each of the undetermined grid points is recorded as a known grid point, the number of iterations reaches the preset maximum number of iterations, and the time for the developer to arrive at the currently selected known grid point is greater than the preset development time threshold.

9. A computer program product comprising a computer program that, when executed by a processor, implements a development simulation method for photoresist according to any one of claims 1 to 8.

10. A computer device comprising a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the photoresist development simulation method according to any one of claims 1 to 8.

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