A simulation method for low-pressure chemical vapor deposition of polycrystalline silicon

Abstract

This invention relates to the field of numerical simulation technology and discloses a simulation method for low-pressure chemical vapor deposition (LPCVD) of polycrystalline silicon. The method includes importing a three-dimensional geometric model of the reactor and simplifying it to obtain a simplified three-dimensional geometric model. The simplified model is then meshed to create a mesh file, which is imported into simulation software. A solver is set up, and within the solver, a physical model is selected, and element and boundary conditions are set. The computational flow field is initialized in the solver, and iterative calculations begin. Upon convergence of the iterative calculations, the gas flow distribution cloud map, temperature change cloud map, and silicon deposition rate cloud map of the reactor are obtained, completing the simulation of LCVD of polycrystalline silicon. This invention shortens the simulation calculation cycle, ensures the accuracy of the simulation results, and provides reliable data support for subsequent improvements to the reactor structure and the uniformity of the deposited film.

Description

Technical Field

[0001] This invention relates to the field of numerical simulation technology, and in particular to a simulation method for low-pressure chemical vapor deposition of polycrystalline silicon. Background Technology

[0002] Low-pressure chemical vapor deposition (LPCVD) refers to chemical vapor deposition performed under conditions below one atmosphere of pressure. In the field of LPCVD for new energy technologies, silane thermal decomposition and the surface deposition effect of polycrystalline silicon are direct factors affecting the uniformity of silicon wafer coating within the reactor. Achieving ideal coating results requires in-depth research into silane thermal decomposition and polycrystalline silicon surface deposition reactions. However, both the chemithermal decomposition reaction and the vapor deposition process are complex, making it extremely difficult to obtain experimental measurements of the chemical reaction results within the reactor and other influencing factors, including fluid distribution characteristics, thermal field, and pressure distribution. Furthermore, the use of software simulation technology to simulate silane thermal decomposition and polycrystalline silicon surface deposition phenomena has not seen any practical application. Aside from some research papers that introduce the chemical formulas, derivation processes, and parameters such as reaction rate and activation energy required for simulation, examples of practical industrial applications are still very scarce.

[0003] The current LPCVD simulation process is not widely used primarily due to three main reasons: First, its complex geometry involves a large number of extremely thin silicon wafers (over 2000 wafers), and a massive reactor with a total length of approximately 3.5 meters. The smallest lengths are on the millimeter scale (diameters of approximately 0.75 mm and 1.5 mm, including 40-50 fine holes on straight and annular spray pipes). This complex geometry leads to a dramatic increase in mesh size and significantly lengthens the simulation computation cycle, necessitating model simplification and mesh optimization to ensure computational feasibility. Second, the physical model is complex (involving various physicochemical phenomena such as turbulence, radiative heat transfer, low pressure, and chemical reactions). Third, determining the model parameters is extremely difficult, requiring experimental acquisition for many parameters, such as the radiation coefficient, convection coefficient, activation energy in chemical reactions, pre-exponential factor, and temperature index. These parameters may require repeated simulations to obtain optimal values. Therefore, existing simulation methods are difficult to apply in practice.

[0004] Therefore, how to provide a method for simulating low-pressure chemical vapor deposition of polycrystalline silicon is a technical problem that needs to be solved. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a simulation method for low-pressure chemical vapor deposition of polycrystalline silicon. This invention can provide a complete simulation process and can also calculate the uniformity of chemically reacted silicon based on the deposition rate of the chemically reacted silicon, providing reliable data support for subsequent design optimization.

[0006] To achieve the above objectives, the present invention provides a simulation method for low-pressure chemical vapor deposition of polycrystalline silicon, the method comprising:

[0007] Import the 3D geometric model of the reactor;

[0008] The three-dimensional geometric model of the reactor is simplified to obtain a simplified three-dimensional geometric model;

[0009] The simplified 3D geometric model is meshed to create a mesh file;

[0010] Import the mesh file into the simulation software and set the solver.

[0011] Select a physical model in the solver, wherein the physical model includes a turbulence model, an energy model, a composition model, and a radiation model;

[0012] Set the element region conditions and boundary conditions in the computational solver;

[0013] The computational flow field is initialized in the solver, and iterative computation and solution are started.

[0014] Once the iterative calculation converges, the gas flow distribution cloud map of the reactor, the temperature change cloud map of the reactor, and the deposition rate cloud map of the chemically reacted silicon are obtained, thus completing the simulation of low-pressure chemical vapor deposition of polycrystalline silicon.

[0015] In one embodiment, simplifying the three-dimensional geometric model of the reactor to obtain a simplified three-dimensional geometric model includes:

[0016] Remove the chamfers and fillets from the three-dimensional geometric model;

[0017] Retain the preset number of boats and boat pieces;

[0018] Obtain the cross-section of the thin sheet of the three-dimensional geometric model and form a wall with zero thickness;

[0019] Based on preset filtering rules, the components on the three-dimensional geometric model are retained or modified.

[0020] Obtain the total number of heat insulation sheets on the three-dimensional geometric model, and reduce the number of heat insulation sheets by half;

[0021] Based on symmetry, half of the three-dimensional geometric model is cut off to obtain a simplified three-dimensional geometric model.

[0022] In one embodiment, the simplified three-dimensional geometric model is meshed, and the mesh file is created by:

[0023] The simplified three-dimensional geometric model is meshed;

[0024] The divided mesh is inspected and processed to obtain qualified and unqualified mesh files. The inspection and processing includes checking the mesh file size ratio, mesh file density, mesh file quality, and mesh number.

[0025] Based on local mesh control, the preset parts in the unqualified mesh file are refined to complete the establishment of the mesh file. The preset parts include the fine holes of the straight spray pipe, the outlet of the straight spray pipe, and the fine holes of the annular spray pipe.

[0026] In one embodiment, the computational solver is a three-dimensional double-precision solver based on the pressure method.

[0027] In one embodiment, setting the element region conditions and boundary conditions in the computational solver includes:

[0028] Set the material or fluid properties of the element region within the computational solver;

[0029] Set the inlet mass flow rate, inlet velocity direction, and inlet temperature of the straight-through spray pipe;

[0030] Set the total inlet mass flow rate, inlet velocity direction, and inlet temperature of the fine orifice of the annular spray pipe;

[0031] Set the outlet pressure of the reactor;

[0032] Set the heat transfer conditions for the physical model.

[0033] In one embodiment, the number of pores in the annular spray pipe is six.

[0034] In one embodiment, when initializing the computational flow field and starting iterative computation in the solver, the process includes:

[0035] Set the initial pressure, the initial flow velocity, and the temperature of the reactor;

[0036] Set the initial concentration of silane;

[0037] The solution is obtained through iterative calculation based on the initial pressure, initial flow velocity, temperature, and initial concentration of silane in the reactor.

[0038] In one embodiment, after obtaining the gas flow distribution cloud map of the reactor, the temperature change cloud map of the reactor, and the deposition rate cloud map of the chemically reacted silicon, the method further includes:

[0039] The airflow pattern and velocity within the reactor are determined based on the airflow distribution cloud map of the reactor.

[0040] The temperature distribution within the reactor is determined based on the temperature change cloud map of the reactor.

[0041] In one embodiment, it further includes:

[0042] The deposition rate of the chemically reacted silicon is obtained from the deposition rate cloud map of the chemically reacted silicon.

[0043] The uniformity of the chemically reacted silicon is calculated based on the deposition rate of the silicon in the chemical reaction.

[0044] In one embodiment, the uniformity of the chemically reacted silicon is calculated according to the following formula:

[0045] M = (R max -R min ) / (R max +R min );

[0046] Where M represents the uniformity of silicon in the chemical reaction, and R... max R represents the maximum value of the silicon deposition rate obtained through chemical reaction. min This represents the minimum silicon deposition rate achieved through chemical reaction.

[0047] This invention provides a simulation method for low-pressure chemical vapor deposition of polycrystalline silicon, which has the following advantages compared with the prior art:

[0048] (1) By simplifying the three-dimensional geometric model, the present invention can avoid the three-dimensional geometric model being too complex and thus affecting the number of subsequent meshes, saving computational costs and shortening the simulation calculation cycle and design cycle.

[0049] (2) The present invention refines the preset parts in some mesh files based on local mesh control, which can effectively improve the generation quality and number of mesh files.

[0050] (3) The present invention sets up a calculation solver and iteratively calculates and solves in the calculation solver to obtain the uniformity of silicon deposition in chemical reaction. This can effectively improve the accuracy of simulation calculation results and provide reliable data support for the improvement of reactor structure and deposition film uniformity. Attached Figure Description

[0051] Figure 1 A schematic flowchart of a simulation method for low-pressure chemical vapor deposition of polycrystalline silicon is shown in an embodiment of the present invention.

[0052] Figure 2 A schematic diagram of a three-dimensional geometric model of the reactor in an embodiment of the present invention is shown;

[0053] Figure 3 A schematic diagram of the process for simplifying the three-dimensional geometric model of the reactor in an embodiment of the present invention is shown;

[0054] Figure 4 A simplified three-dimensional geometric model schematic diagram is shown in an embodiment of the present invention;

[0055] Figure 5 This diagram illustrates the process of refining the fine holes and outlet of the straight-through spray pipe based on local grid control in an embodiment of the present invention.

[0056] Figure 6 This illustration shows a schematic diagram of the refinement of the fine holes and outlet of the straight-through spray pipe based on local grid control in an embodiment of the present invention.

[0057] Figure 7 This diagram illustrates the refinement of the fine holes in the annular spray pipe based on local grid control in an embodiment of the present invention.

[0058] Figure 8 A cross-sectional grid diagram of the fine holes in the straight-through spray pipe in an embodiment of the present invention is shown;

[0059] Figure 9 An airflow distribution cloud map of the reactor in an embodiment of the present invention is shown;

[0060] Figure 10 A cloud map of the deposition rate of chemically reacted silicon in an embodiment of the present invention is shown.

[0061] In the diagram, 1 is the air inlet; 2 is the air outlet; 3 is the furnace tail cover; 4 is the quartz tube; 5 is the silicon wafer boat; 6 is the boat support; 7 is the heat insulation sheet; 8 is the furnace mouth cover; 9 is the load-bearing paddle; 10 is the straight spray pipe; 11 is the fine hole of the straight spray pipe before refining; 12 is the outlet of the straight spray pipe before refining; 13 is the annular spray pipe; 14 is the fine hole of the annular spray pipe before refining; 15 is the fine hole of the straight spray pipe after refining; and 16 is the outlet of the straight spray pipe after refining. Detailed Implementation

[0062] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0063] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0064] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0065] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0066] The following is a description of preferred embodiments of the present invention in conjunction with the accompanying drawings.

[0067] like Figure 1 , Figure 2 As shown, an embodiment of the present invention discloses a simulation method for low-pressure chemical vapor deposition of polycrystalline silicon, the method comprising:

[0068] S110: Import the three-dimensional geometric model of the reactor.

[0069] In this embodiment, the three-dimensional geometric model of the reactor is imported into three-dimensional drawing software. The three-dimensional drawing software includes AutoCAD, UR, PRO / E, 3Ds MAX, Solidworks, CATIA, etc. The specific three-dimensional drawing software can be selected according to actual needs, and no specific limitation is made here.

[0070] S120: The three-dimensional geometric model of the reactor is simplified to obtain a simplified three-dimensional geometric model.

[0071] In this embodiment, by simplifying the three-dimensional geometric model of the reactor, the simulation difficulty of the three-dimensional geometric model is reduced, and the simulation calculation cycle is effectively shortened.

[0072] like Figure 3 , Figure 4 As shown, in order to reduce the complexity of the three-dimensional geometric model of the reactor, in some embodiments of this application, the three-dimensional geometric model of the reactor is simplified, and when the simplified three-dimensional geometric model is obtained, the chamfers and fillets of the three-dimensional geometric model are deleted, and a preset number of boats and boat pieces are retained.

[0073] It should be understood that a fillet refers to connecting two intersecting objects or two parts of an object at a certain angle with a specified arc at the intersection point; while a chamfer refers to replacing the arc segment used for a fillet with a straight line. By deleting the chamfers and fillets of the 3D geometric model, retaining 10 boats, and retaining 16 boat pieces in each boat, the cross-section of the thin pieces is extracted and a wall without thickness is formed, which can avoid the phenomenon of having too many structures in the 3D geometric model, thus increasing the simulation difficulty.

[0074] In some embodiments of this application, the cross-section of the thin sheet of the three-dimensional geometric model is obtained and a wall without thickness is formed. Based on a preset screening rule, the components on the three-dimensional geometric model are retained or modified. The total number of heat insulation sheets 7 on the three-dimensional geometric model is obtained and the number of heat insulation sheets 7 is reduced by half. Based on symmetry, half of the three-dimensional geometric model is cut off to obtain a simplified three-dimensional geometric model.

[0075] Specifically, in order to retain important influencing factors and simplify the three-dimensional geometric model of the reactor, this application further presets screening rules. The preset screening rules refer to retaining important influencing factors inside the quartz tube 4, such as the load-bearing paddle 9, and deleting unimportant influencing factors, such as the boat support 6. The specific important and unimportant influencing factors can be set according to the actual situation, and no specific limitation is made here. The number of heat insulation sheets 7 is reduced by half. Finally, half of the three-dimensional geometric model is cut off using symmetry to obtain the simplified three-dimensional geometric model.

[0076] In this embodiment, by simplifying the three-dimensional geometric model of the reactor, the three-dimensional geometric model can be avoided from being too complex, which would affect the number of subsequent meshes, thus saving computational costs and shortening the simulation calculation cycle and design cycle.

[0077] S130: Mesh the simplified three-dimensional geometric model and create a mesh file.

[0078] In this embodiment, the mesh generation software can be any one of ICEM-CFD, CFD-Geom, and TrueGrid, without any specific limitation.

[0079] like Figures 5-8 As shown, in order to improve the generation quality and number of meshes in the mesh file, in some embodiments of this application, the simplified three-dimensional geometric model is meshed. When creating the mesh file, the simplified three-dimensional geometric model is divided into meshes. The divided meshes are inspected to obtain qualified and unqualified mesh files. The inspection process includes checking the mesh file size ratio, mesh file density, mesh file quality, and mesh file number.

[0080] It should be understood that the simplified 3D geometric model is imported into the pre-configured meshing software for mesh generation, and then checked and processed. Specifically, the size ratio, density, mesh quality, and number of meshes in the mesh file are checked to obtain qualified and unqualified mesh files.

[0081] In this embodiment, through inspection and processing, qualified and unqualified mesh files can be obtained. Qualified mesh files are directly imported into the simulation software, while unqualified mesh files require further processing to make them meet the simulation requirements.

[0082] In some embodiments of this application, a preset part in the unqualified mesh file is refined based on local mesh control to complete the establishment of the mesh file. The preset part includes the fine hole of the straight spray pipe 10, the outlet of the straight spray pipe 10 and the fine hole of the annular spray pipe 13.

[0083] It should be understood that, based on local mesh control, preset parts in unqualified mesh files are refined, with 3 boundary layers added to walls without thickness and 5 boundary layers added to other walls.

[0084] In this embodiment, the present invention can effectively improve the generation quality and number of meshes by refining preset parts in unqualified mesh files.

[0085] S140: Import the mesh file into the simulation software and set the calculation solver.

[0086] In some embodiments of this application, the solver is a three-dimensional double-precision solver based on the pressure method.

[0087] In this embodiment, the solver is a three-dimensional double-precision solver based on the pressure method. The time type is set to steady state, the velocity equation is set to absolute, and the gravity vector is set to y = -9.81 m / s.

[0088] S150: Select a physical model in the solver, wherein the physical model includes a turbulence model, an energy model, a composition model, and a radiation model.

[0089] S160: Set the element region conditions and boundary conditions in the solver.

[0090] To improve the accuracy of simulation results, in some embodiments of this application, when setting the element region conditions and boundary conditions in the calculation solver, the following is included: setting the material properties or fluid properties of the element region within the calculation solver.

[0091] It should be understood that if the unit region is a solid, the material properties of the unit region are set; if the unit region is a liquid or gas, the fluid properties of the unit region are set. The material property settings of the unit region include setting solid, gas, and mixture. The specific solid, gas, and mixture can be selected according to the actual design and are not specifically limited here. By setting the material properties of the unit region, the accuracy of the iterative calculation can be further guaranteed.

[0092] In some embodiments of this application, the inlet mass flow rate, inlet velocity direction, and inlet temperature of the straight spray pipe 10 are set; the total inlet mass flow rate, inlet velocity direction, and inlet temperature of the fine holes of the annular spray pipe 13 are set; and the outlet pressure of the reactor is set.

[0093] It should be understood that the inlet mass flow rate of the straight-through spray pipe 10 can be set to 2.14e-5 kg / s (approximately 0.9 L / min at standard atmospheric pressure), with the inlet velocity direction perpendicular to the inlet surface, the inlet temperature at 26°C, and the silane mass concentration set to 1. The total inlet mass flow rate of the orifices of the annular spray pipe 13 is set to 3.57e-6 kg / s (approximately 0.1 L / min at standard atmospheric pressure), with the flow rate evenly distributed to each inlet. The annular spray pipe 13 has six orifices, with the inlet velocity direction perpendicular to the inlet surface, the inlet temperature at 26°C, and the silane mass concentration set to 1. The reactor outlet static pressure is -101286.5 Pa (equivalent to an absolute pressure of 38.5 Pa), which helps to reduce the difficulty of simulation calculations.

[0094] In some embodiments of this application, heat transfer conditions for the physical model are also defined.

[0095] It should be understood that the internal walls of the physical model are all set to coupled heat transfer, and the walls in contact with the outside are all set to convective heat transfer (convective coefficient of 5W / m-℃) and radiative heat dissipation (radiative coefficient of 1), and the ambient temperature is 26℃.

[0096] In this embodiment, the accuracy of simulation calculation results can be effectively improved, providing reliable data support for the improvement of reactor structure and the uniformity of deposited films.

[0097] S170: Initialize the computational flow field in the solver and begin iterative computation to solve the problem.

[0098] To further improve the accuracy of simulation results, in some embodiments of this application, when initializing the computational flow field and starting iterative computation in the solver, the following steps are included:

[0099] The initial pressure, initial flow velocity, and temperature of the reactor are set, and the initial concentration of silane is set. Based on the initial pressure, initial flow velocity, temperature, and initial concentration of silane, iterative calculations are performed to solve the problem.

[0100] It should be understood that the pressure inside the reactor is -101285 (equivalent to an absolute pressure of 40 Pa), and the initial flow velocity in the xyz direction is 0 m / s. The xyz direction refers to a Cartesian coordinate system: x represents the horizontal axis, y represents the vertical axis, and z represents the center axis. When using a Cartesian coordinate system, x, y, and z axes are usually set; these three axes are essentially the three directions of three-dimensional space, i.e., the horizontal, vertical, and center axes. The initial temperature inside the reactor is 600℃, and the initial concentration of silane is set to 0.1. After setting these parameters, iterative solutions are performed.

[0101] In this embodiment, in order to ensure the accuracy of the iterative solution, the present invention initializes the computational flow field before performing the iterative solution.

[0102] S180: After the iterative calculation converges, the gas flow distribution cloud map of the reactor, the temperature change cloud map of the reactor, and the deposition rate cloud map of the chemically reacted silicon are obtained, thus completing the simulation of low-pressure chemical vapor deposition of polycrystalline silicon.

[0103] In this embodiment, when performing iterative calculations, once the residual value reaches or approaches the preset value, it can be determined that the calculation has converged, and the calculation can be terminated. This yields the gas flow distribution cloud map of the reactor, the temperature change cloud map of the reactor, and the deposition rate cloud map of silicon in the chemical reaction, thus completing the simulation of low-pressure chemical vapor deposition of polycrystalline silicon.

[0104] like Figure 9As shown, in order to determine the airflow pattern, airflow velocity, and temperature distribution state within the reactor, in some embodiments of this application, after obtaining the airflow distribution cloud map, the temperature change cloud map, and the deposition rate cloud map of the chemically reacted silicon, the method further includes: determining the airflow pattern and airflow velocity within the reactor based on the airflow distribution cloud map; and determining the temperature distribution state within the reactor based on the temperature change cloud map.

[0105] In this embodiment, the airflow distribution cloud map is used to view the airflow pattern and speed within the reactor. It can be used to determine where the airflow is more active. For example, if the color on the airflow distribution cloud map is reddish, it means that the speed in that area is relatively high, and if the color is blue, it means the opposite. Based on the same principle, the temperature distribution state within the reactor can be determined using the temperature change cloud map.

[0106] like Figure 10 As shown, in order to compare the simulation results with the field data, some embodiments of this application further include: obtaining the deposition rate of the chemically reacted silicon based on the deposition rate cloud map of the chemically reacted silicon; and calculating the uniformity of the chemically reacted silicon based on the deposition rate of the chemically reacted silicon.

[0107] In some embodiments of this application, the uniformity of the chemically reacted silicon is calculated according to the following formula:

[0108] M = (R max -R min ) / (R max +R min );

[0109] Where M represents the uniformity of silicon in the chemical reaction, and R... max R represents the maximum value of the silicon deposition rate obtained through chemical reaction. min This represents the minimum silicon deposition rate achieved through chemical reaction.

[0110] In this embodiment, simulation results are shown for the first and fifth silicon wafers (counted from top to bottom), the middle wafer, and the first and fifth silicon wafers (counted from bottom to top). The uniformity of chemically reacted silicon deposition is calculated using the deposition rate of the chemically reacted silicon. This uniformity is then compared with field data. Uniformity comparisons can be performed within wafers, between wafers, and between boats. This helps identify the causes of uneven film thickness, which facilitates subsequent optimization and improvement of the reactor structure and flow field parameters to enhance the uniformity of the deposited film.

[0111] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0112] Although the invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, features in the embodiments disclosed herein can be combined with each other in any manner, provided there is no structural conflict. The omission of all such combinations in this specification is merely for brevity and resource conservation. Therefore, the invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0113] It will be understood by those skilled in the art that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A simulation method for low-pressure chemical vapor deposition of polycrystalline silicon, characterized in that, The method includes: Import the 3D geometric model of the reactor; The three-dimensional geometric model of the reactor is simplified to obtain a simplified three-dimensional geometric model; The simplified 3D geometric model is meshed to create a mesh file; Import the mesh file into the simulation software and set the solver. Select a physical model in the solver, wherein the physical model includes a turbulence model, an energy model, a composition model, and a radiation model; Set the element region conditions and boundary conditions in the computational solver; The computational flow field is initialized in the solver, and iterative computation and solution are started. Once the iterative calculation converges, the gas flow distribution cloud map of the reactor, the temperature change cloud map of the reactor, and the deposition rate cloud map of the chemically reacted silicon are obtained, thus completing the simulation of low-pressure chemical vapor deposition of polycrystalline silicon. When creating a mesh file for the simplified 3D geometric model, the following steps are included: The simplified three-dimensional geometric model is meshed; The divided mesh is inspected and processed to obtain qualified and unqualified mesh files. The inspection and processing includes checking the mesh file size ratio, mesh file density, mesh file quality, and mesh number. Based on local mesh control, the preset parts in the unqualified mesh file are refined to complete the establishment of the mesh file. The preset parts include the fine holes of the straight spray pipe, the outlet of the straight spray pipe, and the fine holes of the annular spray pipe. Setting the element region conditions and boundary conditions in the solver includes: Set the material or fluid properties of the element region within the computational solver; Set the inlet mass flow rate, inlet velocity direction, and inlet temperature of the straight-through spray pipe; Set the total inlet mass flow rate, inlet velocity direction, and inlet temperature of the fine orifice of the annular spray pipe; Set the outlet pressure of the reactor; Set the heat transfer conditions for the physical model; When initializing the computational flow field and starting iterative computation in the solver, the process includes: Set the initial pressure, the initial flow velocity, and the temperature of the reactor; Set the initial concentration of silane; The solution is obtained through iterative calculation based on the initial pressure of the reactor, the initial flow velocity of the reactor, the temperature of the reactor, and the initial concentration of the silane. The deposition rate of the chemically reacted silicon is obtained from the deposition rate cloud map of the chemically reacted silicon. The uniformity of the chemically reacted silicon is calculated based on the deposition rate of the silicon in the chemical reaction.

2. The simulation method for low-pressure chemical vapor deposition of polycrystalline silicon according to claim 1, characterized in that, Simplifying the three-dimensional geometric model of the reactor to obtain the simplified three-dimensional geometric model includes: Remove the chamfers and fillets from the three-dimensional geometric model; Retain the preset number of boats and boat pieces; Obtain the cross-section of the thin sheet of the three-dimensional geometric model and form a wall with zero thickness; Based on preset filtering rules, the components on the three-dimensional geometric model are retained or modified. Obtain the total number of heat insulation sheets on the three-dimensional geometric model, and reduce the number of heat insulation sheets by half; Based on symmetry, half of the three-dimensional geometric model is cut off to obtain a simplified three-dimensional geometric model.

3. The simulation method for low-pressure chemical vapor deposition of polycrystalline silicon according to claim 1, characterized in that, The computational solver is a three-dimensional double-precision solver based on the pressure method.

4. The simulation method for low-pressure chemical vapor deposition of polycrystalline silicon according to claim 1, characterized in that, The annular spray pipe has six fine holes.

5. The simulation method for low-pressure chemical vapor deposition of polycrystalline silicon according to claim 1, characterized in that, After obtaining the gas flow distribution cloud map, the temperature change cloud map, and the deposition rate cloud map of the chemically reacted silicon in the reactor, the process further includes: The airflow pattern and velocity within the reactor are determined based on the airflow distribution cloud map of the reactor. The temperature distribution within the reactor is determined based on the temperature change cloud map of the reactor.

6. The simulation method for low-pressure chemical vapor deposition of polycrystalline silicon according to claim 1, characterized in that, The uniformity of silicon in a chemical reaction is calculated using the following formula: ； Where M represents the uniformity of silicon in the chemical reaction, and R... max R represents the maximum value of the silicon deposition rate obtained through chemical reaction. min This represents the minimum silicon deposition rate achieved through chemical reaction.

Images