Photoresist development simulation method, computer readable storage medium and computer program product

Abstract

The invention provides a photoresist development simulation method, a computer readable storage medium and a computer program product.The photoresist development simulation method comprises the steps that a photoresist development model is divided into grids, and whether photoresist resin makes contact with a development solvent or not is judged according to the occupancy state of grid points of the grids, the method for determining the occupancy state of the lattice points of the grid comprises the following steps: constructing a sphere in a photoresist developing model, taking a unit group of photoresist resin as a sphere center of the sphere, and taking the sum of the Van der Waals radius of the unit group of the photoresist resin and the Van der Waals radius of a developing solvent as a radius of the sphere; and traversing the sphere, and if the lattice points are surrounded by the sphere, adding 1 to the occupancy state of the lattice points. According to the developing simulation method for judging whether the photoresist resin is in contact with the developing solvent or not through the Van der Waals radius of the photoresist resin and the Van der Waals radius of the developing solvent, the influence of the permeation behavior of the developing solvent in the photoresist resin on photoresist developing is accurately and effectively reflected; and the method has guiding significance for researching the influence of different resin structures on the photoresist developing result.

Description

Technical Field

[0001] This invention relates to the field of materials simulation, and more particularly to a photoresist development simulation method, a computer-readable storage medium, and a computer program product. Background Technology

[0002] Photoresist, as a pattern transfer medium, is a key material in integrated circuit manufacturing. Taking chemically amplified photoresist as an example, the photolithography process includes spin coating, pre-baking, exposure, post-baking, and development. The development step involves dissolving the polarity-reversed resin material in the developer to form the photolithographic pattern. The development rate and defects in the developed morphology have a significant impact on the quality of pattern transfer.

[0003] Modeling the development process by starting with the microstructure of photolithography materials helps to study the influence of material structure on the development process, thereby guiding the research and development of photoresist materials.

[0004] Traditional photolithography simulation methods based on simplified physical models cannot explicitly consider the microstructure of photoresist resin. While development simulation methods based on critical ionization models can explicitly consider the chain length and structural distribution characteristics of photoresist resin, they divide the spatial distribution of different resin groups into stacks of cubic units of the same volume to determine whether they come into contact with the solvent. However, photoresist resin is generally a disordered structure in a glassy state. The simplified structure of resin groups arranged regularly in a cubic form cannot accurately reflect the structural characteristics of the resin and is difficult to apply to resin groups with significant volume differences. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a photoresist development simulation method, a computer-readable storage medium, and a computer program product that can explicitly consider the chain length and structural distribution characteristics of the photoresist resin and accurately reflect the influence of the photoresist resin structure on the development process.

[0006] To address the above problems, the present invention provides a photoresist development simulation method, the simulation method comprising:

[0007] A photoresist development model is constructed, the photoresist development model including a photoresist resin region and a development solvent region located on the photoresist resin region;

[0008] The photoresist development model is divided into a grid, and the occupancy state of the grid points is determined. The initial occupancy state of the grid points is 0. The method for determining the occupancy state of the grid points is as follows: a sphere is constructed in the photoresist development model, with the unit group of the photoresist resin as the center and the sum of the van der Waals radius of the unit group of the photoresist resin and the van der Waals radius of the developing solvent as the radius; the sphere is traversed, and if a grid point is surrounded by the sphere, the occupancy state of the grid point is incremented by 1.

[0009] The execution unit steps include: determining the connectivity between grid points with an occupancy state of 0, dividing the connected grid points with an occupancy state of 0 into a free region; obtaining the unit groups of the photoresist resin in contact with the free region connected to the developing solvent region; performing an ionization equilibrium reaction; traversing the polymer chains containing the unit groups of the photoresist resin in contact with the free region connected to the developing solvent region, and removing the polymer chains if the ionization degree of the polymer chains is greater than a critical value; and updating the grid point occupancy state.

[0010] The unit steps are repeated until no polymer chains can be removed, at which point the photoresist development simulation ends.

[0011] In one embodiment, the photoresist development model is constructed using molecular dynamics simulation.

[0012] In one embodiment, the molecular dynamics method includes either a full-atom molecular dynamics simulation method or a coarse-grained molecular dynamics simulation method. When a full-atom molecular dynamics simulation method is used to construct a photoresist development model, the unit groups of the photoresist resin are the individual atoms in the photoresist resin. When a coarse-grained molecular dynamics simulation method is used to construct a photoresist development model, the unit groups of the photoresist resin are the beads in the coarse-grained molecular dynamics simulation.

[0013] In one embodiment, the step of constructing a photoresist development model further includes: generating a text file containing the microstructural features of the photoresist system, and parsing the text file to obtain parameter information of the photoresist development model. The parameter information includes at least the three-dimensional dimensions of the photoresist development model, the types of each unit group of the photoresist resin, the connection relationship between the unit groups of the photoresist resin, and the coordinate information of the photoresist development model.

[0014] In one embodiment, after determining the occupancy state of the grid points, a three-dimensional matrix composed of the occupancy states of the grid points is obtained. In the unit step, the step of dividing the grid points with a connected occupancy state of 0 into a free region further includes: dividing the grid points with a connected occupancy state of 0 into a free region in the three-dimensional matrix.

[0015] In one embodiment, the free regions are assigned identifiers to distinguish different free regions.

[0016] In one embodiment, the Hoshen-Kopelman algorithm or the spanning tree algorithm is used in the three-dimensional matrix to determine the connectivity between grid points with an occupation state of 0.

[0017] In one embodiment, the step of obtaining unit groups of the photoresist resin in contact with the free region communicating with the developing solvent region in the unit step further includes: obtaining boundary grid points of the free region communicating with the developing solvent region; and obtaining unit groups of the photoresist resin in contact with the free region communicating with the developing solvent region through the boundary grid points.

[0018] In one embodiment, the step of obtaining the unit group of photoresist resin in contact with the free region communicating with the developing solvent region through the boundary grid points further includes: obtaining the grid points outside the free region adjacent to the boundary grid points; and using the unit group of photoresist resin containing the grid points adjacent to the boundary grid points as the unit group of photoresist resin in contact with the free region.

[0019] In one embodiment, the step of updating the grid occupancy state in the unit step further includes: updating the three-dimensional matrix.

[0020] In one embodiment, the step of performing the ionization equilibrium reaction in the unit step further includes: determining whether the unit group of the photoresist resin in contact with the free region connected to the developing solvent region is an ionizable unit group; if so, the unit group of the photoresist resin in contact with the free region connected to the developing solvent region undergoes an ionization reaction with an ionization probability and a deionization reaction with a deionization probability, wherein the ionization reaction and the deionization reaction are reversible reactions.

[0021] In one embodiment, the step of traversing the polymer chain containing the unit groups of the photoresist resin in contact with the free region communicating with the developing solvent region further includes traversing the polymer chain starting from the end of the polymer chain.

[0022] In one embodiment, the step of traversing the polymer chain containing the unit groups of the photoresist resin in contact with the free region connected to the developing solvent region further includes: starting from the end of the polymer chain, determining that polymer chain segments with an ionization degree greater than a critical value are solvent-permeable, and decrementing the occupancy state of the lattice points contained in the unit groups on the polymer chain segment by 1.

[0023] This invention also provides a computer-readable storage medium storing a control program, which, when executed by a processor, implements the photoresist development simulation method as described above.

[0024] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the photoresist development simulation method as described above.

[0025] The photoresist development simulation method provided in this embodiment of the invention divides the photoresist development model into a grid and determines whether the photoresist resin is in contact with the developing solvent based on the occupancy state of the grid points. The method for determining the occupancy state of the grid points is as follows: a sphere is constructed in the photoresist development model, with the unit group of the photoresist resin as the center and the sum of the van der Waals radius of the unit group of the photoresist resin and the van der Waals radius of the developing solvent as the radius; the sphere is traversed, and if a grid point is surrounded by the sphere, the occupancy state of the grid point is incremented by 1. This method involves constructing a sphere in the photoresist development model with the unit groups of the photoresist resin as the center and the sum of the van der Waals radii of the unit groups of the photoresist resin and the van der Waals radii of the developing solvent as the radius. This sphere is used to determine the occupancy state of the grid points, thereby determining whether the photoresist resin is in contact with the developing solvent. This development simulation method, which uses the van der Waals radii of the photoresist resin and the developing solvent to determine whether the photoresist resin is in contact with the developing solvent, accurately and effectively reflects the influence of the developing solvent's penetration behavior within the photoresist resin on photoresist development. It has guiding significance for studying the influence of different resin structures on photoresist development results. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the steps of a photoresist development simulation method provided in an embodiment of the present invention;

[0028] Figure 2 This is a photoresist development model constructed using a coarse-grained molecular dynamics simulation method in a photoresist development simulation method provided in an embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram showing the relationship between the grid and the sphere of the photoresist development model in a photoresist development simulation method provided in an embodiment of the present invention.

[0030] Figure 4 This refers to the morphological changes of a photoresist resin with an average degree of polymerization of 30 during the development simulation process in a photoresist development simulation method provided in an embodiment of the present invention. Detailed Implementation

[0031] The following detailed description, in conjunction with the accompanying drawings, illustrates the specific implementation methods of the photoresist development simulation method, computer-readable storage medium, and computer program product provided by the present invention.

[0032] Figure 1 This is a schematic diagram illustrating the steps of a photoresist development simulation method according to an embodiment of the present invention. Please refer to [link / reference]. Figure 1 The photoresist development simulation method includes:

[0033] Step S10: Construct a photoresist development model, which includes a photoresist resin region and a development solvent region located on the photoresist resin region. In this step, a photoresist development model with a set degree of photoresist resin polymerization is constructed.

[0034] In one embodiment, the photoresist development model is constructed using molecular dynamics (MD) simulation. The molecular dynamics simulation method includes either all-atomistic molecular dynamics (AAMD) simulation or coarse-grained molecular dynamics (CGMD) simulation. Coarse-grained molecular dynamics simulation typically groups selected atoms into beads, simplifying the particle representation. This significantly reduces the degrees of freedom required for computation, thereby accelerating the simulation. Figure 2 This is a photoresist development model constructed using a coarse-grained molecular dynamics simulation method. Please refer to [link / reference]. Figure 2 The photoresist development model includes a substrate region 200, a photoresist resin region 210 located above the substrate region 200, and a development solvent region 220 located above the photoresist resin region 210.

[0035] In one embodiment, the step of constructing a photoresist development model further includes: generating a text file containing the microstructural features of the photoresist system, and parsing the text file to obtain parameter information of the photoresist development model. The parameter information includes at least the three-dimensional dimensions of the photoresist development model, the types of each unit group of the photoresist resin, the connection relationships between the unit groups of the photoresist resin, and the coordinate information of the photoresist development model. The types of each unit group of the photoresist resin include whether the unit groups are ionizable or deionizable.

[0036] In some embodiments, when a photoresist development model is constructed using an all-atom molecular dynamics simulation method, the unit groups of the photoresist resin are the individual atoms in the photoresist resin. The parameter information includes at least the three-dimensional dimensions of the photoresist development model, the types of individual atoms in the photoresist resin, the inter-atomic connections of the photoresist resin, and the coordinate information of each atom in the photoresist resin.

[0037] In some embodiments, when a coarse-grained molecular dynamics simulation method is used to construct a photoresist development model, the unit groups of the photoresist resin are beads in the coarse-grained molecular dynamics simulation. The parameter information includes at least the three-dimensional dimensions of the photoresist development model, the type of each bead of the photoresist resin, the connection relationship between the beads of the photoresist resin, and the coordinate information of each bead of the photoresist resin.

[0038] Please continue reading. Figure 1 Step S11: Divide the photoresist development model into a grid and determine the occupancy state of the grid points. The initial occupancy state of the grid points is 0. The method for determining the occupancy state of the grid points is as follows: Construct spheres in the photoresist development model. The spheres are centered on the unit groups of the photoresist resin and have a radius equal to the sum of the van der Waals radii of the unit groups of the photoresist resin and the van der Waals radii of the developing solvent. Traverse the spheres. If a grid point is surrounded by the spheres, the occupancy state of the grid point is incremented by 1.

[0039] In some embodiments, the photoresist development model is divided into a grid according to its three-dimensional dimensions. Each grid point is distributed across the substrate region, the photoresist resin region, and the developing solvent region of the photoresist development model.

[0040] The occupancy state of a grid point refers to the situation where the grid point is surrounded by a sphere with the unit group of the photoresist resin as its center and the sum of the van der Waals radii of the unit group of the photoresist resin and the van der Waals radii of the developing solvent as its radius. Here, "with the unit group of the photoresist resin as its center" means taking the center of the unit group of the photoresist resin as its center. The initial occupancy state of the grid point is 0. If the grid point is surrounded by one sphere, its occupancy state is 1; if the grid point is surrounded by two spheres, its occupancy state is 2.

[0041] For example, Figure 3 This is a schematic diagram illustrating the relationship between the grid and the spheres of the photoresist development model in a photoresist development simulation method provided by an embodiment of the present invention. Please refer to [link / reference]. Figure 3Multiple photoresist resin unit groups 300 are linked to form polymer chains. The regions between adjacent polymer chains are areas that can be filled by solvent. A sphere is constructed with the photoresist resin unit groups 300 as the center and the sum of the van der Waals radii of the photoresist resin unit groups 300 and the van der Waals radii of the developing solvent molecules 310 as the radius (e.g., ...). Figure 3 (As shown by the dashed line in the middle) The occupancy status of a grid point located within the sphere is determined by the number of spheres in which the grid point is located. For example, if grid point A1 is located only within sphere B1, then the occupancy status of grid point A1 is 1. If grid point A2 is located within both spheres B1 and B2, then the occupancy status of grid point A2 is 2. If grid point A3 is not located within a sphere, then the occupancy status of grid point A3 is 0.

[0042] In this embodiment of the invention, spheres are constructed in the photoresist development model. The spheres are centered on the unit groups of the photoresist resin, and their radii are the sum of the van der Waals radii of the unit groups of the photoresist resin and the van der Waals radii of the developing solvent. During the traversal of the spheres, if a grid point is surrounded by one of the spheres, the occupancy status of the grid point is incremented by 1. If the grid point is also surrounded by another sphere, the occupancy status of the grid point is incremented by 1 again, and so on. At the end of the traversal, the final occupancy status of the grid point is obtained.

[0043] In some embodiments, after determining the occupancy state of the grid points, a three-dimensional matrix composed of the occupancy states of the grid points is obtained. In subsequent unit steps, the three-dimensional matrix can be updated according to the changes in the occupancy states of the grid points, and the correlation between each grid point can also be obtained through the three-dimensional matrix, which simplifies the simulation method and helps to speed up the simulation.

[0044] Please continue reading. Figure 1 Step S12, execution unit step, the unit step includes: determining the connectivity between grid points with an occupation state of 0, dividing the connected grid points with an occupation state of 0 into a free region; obtaining the unit groups of the photoresist resin in contact with the free region connected to the developing solvent region; performing an ionization equilibrium reaction; traversing the polymer chains containing the unit groups of the photoresist resin in contact with the free region connected to the developing solvent region, if the ionization degree of the polymer chain is greater than a critical value, then removing the polymer chain; updating the grid point occupation state.

[0045] In the photoresist development model, the developing solvent region is located on the photoresist resin region. Since the developing solvent penetrates from top to bottom, the free region defined in this step is divided into free regions that are connected to the developing solvent region and free regions that are not connected to the developing solvent region. For example, the free region located above or inside the photoresist resin region and in contact with the developing solvent is a free region connected to the developing solvent region and is filled with the developing solvent; the free region located inside the photoresist resin region and not in contact with the developing solvent is a free region not connected to the developing solvent region and can be filled with the developing solvent.

[0046] In the three-dimensional matrix, the Hoshen-Kopelman algorithm or the spanning tree algorithm is used to determine the connectivity between grid points with an occupancy state of 0. A connected grid point with an occupancy state of 0 is defined as one grid point with an occupancy state of 0, and its adjacent grid point also having an occupancy state of 0. These two connected grid points are then assigned to the same free region. For example, please refer to [link / reference needed]. Figure 3 The grid points in the region between two adjacent polymer chains (the region between the two dashed lines) are not located in the sphere. The occupancy state of these grid points is 0, which constitutes the free region 320. The free region 320 is a free region that is not connected to the developing solvent region. The free region 320 can be filled with developing solvent.

[0047] Furthermore, in the unit step, the step of dividing the connected grid points with an occupied state of 0 into a free region further includes: dividing the connected grid points with an occupied state of 0 into a free region in the three-dimensional matrix. Further, in the following embodiments, the method further includes: assigning an identifier to the free region in the three-dimensional matrix to distinguish different free regions. Specifically, the same identifier is assigned to the same free region, and different identifiers are assigned to different free regions. The identifier can be a number, symbol, color, etc. In some embodiments, the developing solvent region can be considered as a free region, which is assigned an identifier. If the identifier of the free region corresponding to a grid point with an occupied state of 0 is the same as the identifier of the developing solvent region, it indicates that the free region corresponding to that grid point is connected to the developing solvent region.

[0048] In the unit step, after determining the free region, unit groups of the photoresist resin that are in contact with the free region communicating with the developing solvent region are obtained. In some embodiments, the method for obtaining unit groups of the photoresist resin that are in contact with the free region communicating with the developing solvent region includes: obtaining boundary grid points of the free region communicating with the developing solvent region, and obtaining unit groups of the photoresist resin that are in contact with the free region communicating with the developing solvent region through the boundary grid points.

[0049] Further, the step of obtaining the unit group of photoresist resin in contact with the free region communicating with the developing solvent region through the boundary grid points includes: obtaining grid points outside the free region adjacent to the boundary grid points; and using the unit group of photoresist resin containing the grid points adjacent to the boundary grid points as the unit group of photoresist resin in contact with the free region. Specifically, if the grid point adjacent to the boundary grid point is located within a sphere with a radius equal to the sum of the van der Waals radius of the unit group of the photoresist resin and the van der Waals radius of the developing solvent, then the unit group of that photoresist resin is used as the unit group of photoresist resin in contact with the free region.

[0050] In some embodiments, the method for obtaining grid points adjacent to the boundary grid points outside the free region may include: obtaining the coordinates of the boundary grid points through the coordinate information of the photoresist development model, obtaining the coordinates of the grid points adjacent to the boundary grid points outside the free region by moving the coordinates of the boundary grid points by a unit length, and then obtaining the grid points located at the coordinates based on the coordinates.

[0051] After obtaining the unit groups of the photoresist resin in contact with the free region connected to the developing solvent region, the photoresist developing model undergoes an ionization equilibrium reaction. In each unit step, if the unit groups of the photoresist resin in contact with the free region connected to the developing solvent region are ionizable, then the unit groups of the photoresist resin in contact with the free region undergo an ionization reaction with an ionization probability α and a deionization reaction with a deionization probability β. The ionization reaction and the deionization reaction are reversible. The ionization probability α can be set manually according to the type of photoresist resin, and the deionization probability β = 1 - α.

[0052] In some embodiments, the step of performing the ionization equilibrium reaction in the unit step further includes: determining whether the unit group of the photoresist resin in contact with the free region connected to the developing solvent region is an ionizable unit group; if so, the unit group of the photoresist resin in contact with the free region connected to the developing solvent region undergoes an ionization reaction with an ionization probability and a deionization reaction with a deionization probability; if not, the ionization equilibrium reaction of the unit group of the photoresist resin in contact with the free region connected to the developing solvent region is terminated.

[0053] In some embodiments, the parameter information of the photoresist development model can be used to determine whether the unit groups of the photoresist resin in contact with the free region connected to the developing solvent region are ionizable unit groups. For example, the type of each unit group of the photoresist resin in the photoresist development model can be used to determine whether the unit groups of the photoresist resin in contact with the free region connected to the developing solvent region are ionizable unit groups.

[0054] After the ionization equilibrium reaction in the photoresist development model, the polymer chains containing the unit groups of the photoresist resin in contact with the free regions connected to the developing solvent region are traversed. If the ionization degree of the polymer chain is greater than a critical value, the polymer chain is removed. The ionization degree of the polymer chain refers to the ratio of the number of ionized unit groups on the polymer chain to the total number of unit groups on the polymer chain. The critical value is related to the type of photoresist resin and is an existing parameter. If the ionization degree of the polymer chain is greater than the critical value, it indicates that the polymer chain has been dissolved by the developing solvent, and the polymer chain is removed.

[0055] In some embodiments, the step of traversing the polymer chain containing the unit groups of the photoresist resin in contact with the free region communicating with the developing solvent region further includes traversing the polymer chain starting from the end of the polymer chain.

[0056] In some embodiments, the step of traversing the polymer chain containing the unit groups of the photoresist resin in contact with the free region communicating with the developing solvent region further includes: starting from the end of the polymer chain, determining that polymer chain segments with an ionization degree greater than a critical value are solvent-permeable, and decrementing the occupancy state of the lattice points contained in the unit groups on the polymer chain segment by 1. This polymer chain segment becomes a suspended chain, i.e., not completely dissolved, but permeable by the developing solvent.

[0057] After traversing the polymer chains containing the unit groups of the photoresist resin in contact with the free regions communicating with the developing solvent region, some polymer chains may be removed, and some polymer chain segments may be made solvent-permeable. This changes the occupancy state of the grid points, requiring an update of the grid point occupancy state to provide the latest grid point occupancy state for subsequent unit steps. In some embodiments, the step of updating the grid point occupancy state further includes updating the three-dimensional matrix.

[0058] The above process is the steps contained in a unit step.

[0059] Please continue reading. Figure 1 Step S13: Repeat the unit steps until no polymer chains can be removed, and the photoresist development simulation ends.

[0060] The photoresist development simulation method provided in this embodiment of the invention divides the photoresist development model into a grid and determines whether the photoresist resin is in contact with the developing solvent based on the occupancy state of the grid points. The method for determining the occupancy state of the grid points is as follows: a sphere is constructed in the photoresist development model, with the unit group of the photoresist resin as the center and the sum of the van der Waals radius of the unit group of the photoresist resin and the van der Waals radius of the developing solvent as the radius; the sphere is traversed, and if a grid point is surrounded by the sphere, the occupancy state of the grid point is incremented by 1. This method involves constructing a sphere in the photoresist development model with the unit groups of the photoresist resin as the center and the sum of the van der Waals radii of the unit groups of the photoresist resin and the van der Waals radii of the developing solvent as the radius. This sphere is used to determine the occupancy state of the grid points, thereby identifying whether the photoresist resin is in contact with the developing solvent. This development simulation method, which uses the van der Waals radii of the photoresist resin and the developing solvent to determine whether the photoresist resin is in contact with the developing solvent, accurately and effectively reflects the influence of the developing solvent's penetration behavior within the photoresist resin on photoresist development. It provides guidance for studying the impact of different resin structures on photoresist development results.

[0061] This invention also provides a computer-readable storage medium storing a control program, which, when executed by a processor, implements the photoresist development simulation method as described above.

[0062] This invention also provides a computer program product, which includes a computer program that, when executed by a processor, implements the photoresist development simulation method as described above.

[0063] The photoresist development simulation method provided in the embodiments of the present invention will be further described with reference to the following examples.

[0064] A method for simulating photoresist development includes:

[0065] (1) Four photoresist development models were constructed using molecular dynamics simulations on silicon substrates. The average degrees of polymerization of the photoresist resins in the four models were 30, 40, 50, and 60, respectively. Each photoresist resin contained one main chain group and two side chain groups. The side chain groups of all four degrees of polymerization were designed to possess ionization reactivity. The van der Waals radius of the main chain group was [missing information]. The van der Waals radii of the two side chain groups are respectively and The van der Waals radius of the silicon atom in the substrate is like Figure 2 As shown, the average degree of polymerization of the photoresist resin in photoresist resin region 220 is 30, and the thickness of the photoresist resin is approximately...

[0066] (2) Adopt The mesh side lengths were used to mesh four photoresist development models. The van der Waals radius of the developing solvent was set to [value missing]. The occupancy state of a grid point is obtained by traversing the photoresist resin unit groups within the photoresist development model. If a grid point is contained within a sphere centered on a photoresist resin unit group and with a radius equal to the sum of the van der Waals radii of the photoresist resin unit group and the van der Waals radii of the developing solvent, the occupancy state of the grid point increases by 1.

[0067] (3) The Hoshen-Kopelman algorithm is adopted. Based on the three-dimensional matrix formed by the grid occupancy status, the connectivity of the grid points with an occupancy status of 0 is judged. The grid points with a connected occupancy status of 0 are divided into a free region, and a unique identifier is set for the same free region.

[0068] (4) Obtain the boundary grid points of the free region connected to the developing solvent region through the identification, and obtain the photoresist resin unit groups in contact with the boundary grid points, and identify them as photoresist resin unit groups in contact with the developing solvent.

[0069] (5) If the photoresist resin unit group in contact with the developing solvent is a side chain unit group of the photoresist resin, then in each simulation step, the ionization reaction occurs with a probability of 0.8 and the deionization reaction occurs with a probability of 0.2.

[0070] (6) After the ionization equilibrium reaction occurs, the polymer chains containing the photoresist resin unit groups in contact with the developing solvent are traversed, and starting from the end of the chain, polymer chain segments with an ionization degree greater than the critical value of 0.5 are defined as solvent-permeable, that is, the occupancy state of the lattice points contained in the unit groups on the polymer chain segment is reduced by 1. At this time, the polymer chain segment becomes a suspended chain, that is, it is not completely dissolved, but it can be permeated by the solvent.

[0071] (7) If the degree of ionization of a complete polymer chain is greater than 0.5 in the current unit step, then remove the polymer chain.

[0072] (8) Update the grid occupancy status and repeat steps (3) to (7) until no polymer chains can be removed and development ends.

[0073] In this example, the simulated development steps for the four photoresist resins with average degrees of polymerization of 30, 40, 50 and 60 were 77, 89, 101 and 119, respectively, indicating that increasing the polymer chain length increases the complete development time. Figure 4The figures show the morphological changes of photoresist resin during the development simulation process with an average degree of polymerization of 30. Figure (a) shows the morphology of the photoresist resin at the beginning of the simulation, Figure (b) shows the morphology of the photoresist resin after 30 simulation steps, and Figure (c) shows the morphology of the photoresist resin after 60 simulation steps. As the number of simulation steps increases, the photoresist resin is dissolved.

[0074] It should be noted that the terms "comprising" and "having," and their variations, used in this invention document are intended to cover non-exclusive inclusion. The terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence, unless explicitly indicated by the context; it should be understood that such use of data can be interchanged where appropriate. The term "one or more" depends at least in part on the context and can be used to describe features, structures, or characteristics in a singular sense, or in a plural sense to describe combinations of features, structures, or characteristics. The term "based on" can be understood as not necessarily intended to express an exclusive set of factors, but can instead, also at least in part on the context, allow for the presence of other factors that are not necessarily explicitly described. Furthermore, embodiments and features in embodiments of this invention can be combined with each other without conflict. In addition, descriptions of well-known components and technologies have been omitted in the above description to avoid unnecessarily obscuring the concepts of this invention. In the various embodiments described above, each embodiment focuses on its differences from other embodiments; similar / identical parts between embodiments can be referred to mutually.

[0075] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for simulating photoresist development, characterized in that, include: A photoresist development model is constructed, the photoresist development model including a photoresist resin region and a development solvent region located on the photoresist resin region; The photoresist development model is divided into a grid, and the occupancy state of the grid points is determined. The initial occupancy state of the grid points is 0. The method for determining the occupancy state of the grid points is as follows: a sphere is constructed in the photoresist development model, with the unit group of the photoresist resin as the center and the sum of the van der Waals radius of the unit group of the photoresist resin and the van der Waals radius of the developing solvent as the radius; the sphere is traversed, and if a grid point is surrounded by the sphere, the occupancy state of the grid point is incremented by 1. The execution unit steps include: Determine the connectivity between grid points with an occupation state of 0, and divide the connected grid points with an occupation state of 0 into a free region; The unit groups of the photoresist resin are obtained in contact with the free region that is in communication with the developing solvent region; To carry out an ionization equilibrium reaction; Traverse the polymer chains containing the unit groups of the photoresist resin that are in contact with the free regions connected to the developing solvent region. If the degree of ionization of the polymer chain is greater than a critical value, then remove the polymer chain. Update the grid occupancy status; The unit steps are repeated until no polymer chains can be removed, at which point the photoresist development simulation ends.

2. The photoresist development simulation method according to claim 1, characterized in that, The photoresist development model was constructed using molecular dynamics simulation.

3. The photoresist development simulation method according to claim 2, characterized in that, The molecular dynamics method includes either a whole-atom molecular dynamics simulation method or a coarse-grained molecular dynamics simulation method. When a whole-atom molecular dynamics simulation method is used to construct a photoresist development model, the unit groups of the photoresist resin are each atom in the photoresist resin. When a coarse-grained molecular dynamics simulation method is used to construct a photoresist development model, the unit groups of the photoresist resin are beads in the coarse-grained molecular dynamics simulation.

4. The photoresist development simulation method according to claim 1, characterized in that, The step of constructing a photoresist development model further includes: generating a text file containing the microstructural features of the photoresist system, and parsing the text file to obtain parameter information of the photoresist development model. The parameter information includes at least the three-dimensional dimensions of the photoresist development model, the types of each unit group of the photoresist resin, the connection relationship between the unit groups of the photoresist resin, and the coordinate information of the photoresist development model.

5. The photoresist development simulation method according to claim 1, characterized in that, After determining the occupancy state of the grid points, a three-dimensional matrix composed of the occupancy states of the grid points is obtained. In the unit step, the step of dividing the connected grid points with an occupancy state of 0 into a free region further includes: dividing the connected grid points with an occupancy state of 0 into a free region in the three-dimensional matrix.

6. The photoresist development simulation method according to claim 5, characterized in that, The free regions are assigned identifiers to distinguish different free regions.

7. The photoresist development simulation method according to claim 5, characterized in that, In the three-dimensional matrix, the Hoshen-Kopelman algorithm or the spanning tree algorithm is used to determine the connectivity between grid points with an occupation state of 0.

8. The photoresist development simulation method according to claim 1, characterized in that, In the unit step, the step of obtaining the unit groups of the photoresist resin in contact with the free region communicating with the developing solvent region further includes: Obtain the boundary grid points of the free region connected to the developing solvent region; The unit groups of the photoresist resin that are in contact with the free region connected to the developing solvent region are obtained through the boundary grid points.

9. The photoresist development simulation method according to claim 8, characterized in that, The step of obtaining the unit group of photoresist resin in contact with the free region connected to the developing solvent region through the boundary grid points further includes: obtaining the grid points outside the free region that are adjacent to the boundary grid points; and using the unit group of photoresist resin containing the grid points adjacent to the boundary grid points as the unit group of photoresist resin in contact with the free region.

10. The photoresist development simulation method according to claim 5, characterized in that, In the unit step, the step of updating the grid point occupancy state further includes: updating the three-dimensional matrix.

11. The photoresist development simulation method according to claim 1, characterized in that, In the unit step, the step of performing the ionization equilibrium reaction further includes: determining whether the unit group of the photoresist resin in contact with the free region connected to the developing solvent region is an ionizable unit group; if so, the unit group of the photoresist resin in contact with the free region connected to the developing solvent region undergoes an ionization reaction with an ionization probability and a deionization reaction with a deionization probability, wherein the ionization reaction and the deionization reaction are reversible reactions.

12. The photoresist development simulation method according to claim 1, characterized in that, In the unit step, the step of traversing the polymer chain containing the unit groups of the photoresist resin that are in contact with the free region communicating with the developing solvent region further includes: traversing the polymer chain starting from the end of the polymer chain.

13. The photoresist development simulation method according to claim 1, characterized in that, The step of traversing the polymer chain containing the unit groups of the photoresist resin in contact with the free region connected to the developing solvent region further includes: starting from the end of the polymer chain, determining that polymer chain segments with an ionization degree greater than a critical value are solvent-permeable, and decrementing the occupancy state of the lattice points contained in the unit groups on the polymer chain segment by 1.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a control program that, when executed by a processor, implements the photoresist development simulation method as described in any one of claims 1 to 13.

15. A computer program product, the computer program product comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the photoresist development simulation method as described in any one of claims 1 to 13.

Images