Atmospheric pressure inductively coupled plasma characteristic diagnosis method and generation device

Abstract

The invention discloses an atmospheric pressure inductively coupled plasma characteristic diagnosis method and a generation device, and belongs to the technical field of plasmas. The method comprises the following steps: firstly, obtaining structural parameters of a generator, establishing grids of a geometric model and a numerical model of the geometric model, then establishing a multi-physical field reaction model, setting solver parameters, executing calculation, and finally processing a model result, and performing multi-angle diagnosis and detection on internal characteristics of the plasma. Different modeling strategies can be provided according to different actual requirements, target precision and required cost of users, diagnosis precision and model operation time can be flexibly balanced, various requirements such as early-stage rapid preliminary optimization and later-stage fine adjustment and improvement are met, the dynamic diagnosis model has the advantages of being convenient to set, wide in application field range and the like, and the method is suitable for large-scale popularization and application. And flexible adjustment can be carried out according to various requirements of users.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of plasma, more particularly, to a method for diagnosing the characteristics of atmospheric pressure inductively coupled plasma and a generating device. BACKGROUND

[0002] Atmospheric pressure inductively coupled plasma is a typical thermal plasma, which usually has a high gas temperature, a very high chemical reaction activity, and its jet has a very high energy density and kinetic energy flux. However, as a process that uses process gas as raw material and generates high-temperature, high-reactivity plasma jet through time-varying magnetic field to induce internal alternating electric field, it is extremely difficult to precisely diagnose and detect the plasma characteristics, which not only severely limits the improvement of processing quality and processing stability, but also makes it difficult to achieve precise control of industrial production and processing.

[0003] At present, when using atmospheric pressure inductively coupled plasma for processing, the following needs to be focused on: the gas temperature distribution of the plasma, the concentration distribution of the reactive radical, the number density distribution of the free electron, the concentration distribution of the ions and molecules concerned under a specific process, etc. The current methods for diagnosing and detecting the plasma characteristics in industrial production and processing using atmospheric pressure inductively coupled plasma mainly include two types: contact sensors and non-contact sensors. Contact sensors mainly include temperature sensors, particle mass analyzers (Q-mass), Langmuir probes, etc. Although this type of sensor can quickly obtain the temperature, particle composition, and electron energy and density of the plasma, the induced current of the metal parts will inevitably interfere with the electromagnetic field inside the atmospheric pressure inductively coupled plasma, thereby affecting the actual characteristics of the plasma, making it difficult to obtain true and accurate plasma information. Non-contact sensors mainly include optical emission spectroscopy (OES), infrared thermal imaging, and high-speed camera imaging (CCD), etc. Although this type of sensor can obtain part of the particle composition, radiation temperature, and discharge stability and kinetic characteristics of the plasma without any interference, it is difficult to accurately distinguish the plasma information in a small space range (especially in the integral path) by integrating the optical information on the measurement path to obtain data. For example, the sheath structure of the plasma edge region has a very small spatial size.

[0004] Moreover, the current mainstream plasma characteristic diagnosis technology still has significant deficiencies in multi-dimensional and high-precision information acquisition, and it is difficult to fully grasp the complex physical behavior of the plasma. This information loss makes the intrinsic control of the plasma process characteristics a bottleneck, and it is difficult to realize the effective construction and closed-loop operation of a new generation of intelligent process control system based on the mapping of physical models and actual processes represented by "digital twinning". At present, there is still a lack of non-interference, high spatial resolution, and reliable and fast methods for precise diagnosis and detection of various plasma characteristics in industrial production and processing using atmospheric pressure inductively coupled plasma. SUMMARY

[0005] The present application is aimed at the measurement technical problems existing in the prior art diagnosis technology, and provides a diagnosis method and generating device for atmospheric pressure inductively coupled plasma characteristics.

[0006] To solve the above technical problems, the present application first provides a diagnosis method for atmospheric pressure inductively coupled plasma characteristics, comprising the following steps: S1, obtaining the structural parameters of the generator, establishing the grid of the geometric model and the numerical model thereof; drawing a geometric model in a modeling software according to the actual geometric parameters of the generator structure; S2, establishing a multi-physical field reaction model; setting the boundary conditions of the fluid field, heat transfer field and electromagnetic field, setting the inlet condition, outlet condition and boundary temperature of the model; defining the reaction field of various reactions occurring inside the plasma, and defining the multi-physical field to communicate and integrate the data inside the physical field; S3, setting the solver parameters and performing calculation; S4, processing the model results, and multi-angle diagnosis and detection of the internal characteristics of the plasma.

[0007] Preferably, step S1 comprises: S1.1, drawing a two-dimensional axisymmetric or three-dimensional geometric model of the generator structure in a modeling software according to the actual geometric parameters of the generator structure; S1.2, matching the entire geometric model with a non-structured grid or a structured grid; S1.3, grid encryption is performed on the main body region of the plasma and the interfacial region between the plasma and the inner wall of the generator.

[0008] Preferably, the grid growth rate of the geometric model is 1.05, the overall grid size is 0.5mm-2mm, and the encryption grid size is 0.2mm.

[0009] Preferably, step S2 comprises: S2.1, setting fluid field boundary conditions: setting the inlet conditions of the model according to the process gas components, flow rate and pressure used by the actual plasma generator; setting the outlet conditions of the model according to the processing environment in which the generator is located; S2.2, setting the heat transfer field boundary conditions: setting the temperature boundary of the model according to the interaction relationship between the generator and the external processing environment; S2.3, setting the electromagnetic field boundary conditions: defining the energy source of the electromagnetic field according to the arrangement form of the coil and electrode inside the generator, the interaction form between the electromagnetic field and each interface, and the various energy conversion paths; S2.4, defining the reaction field of various reactions occurring inside the plasma, including elastic collision reactions and excitation reactions, ionization reactions, de-excitation reactions, and recombination reactions in inelastic collision reactions, as well as chemical reactions, dissociation reactions, and recombination reactions caused by the main energy of the plasma after the introduction of other process gases; S2.5, defining the multi-physical field to communicate and integrate the data inside the physical field, so that each calculation result of the numerical model meets the definition and limitation of the physical field.

[0010] Preferably, when setting the heat transfer field boundary conditions, cooling is performed inside the generator coil, and natural convection heat dissipation is performed between the outside of the generator and the atmospheric environment; the gas inlet and outlet temperatures are both 300K.

[0011] Preferably, when setting the electromagnetic field boundary conditions, the energy source of the electromagnetic field is defined according to the arrangement form of the coil and electrode inside the generator, the coil group parameters are defined, the frequency is 13.56MHz, and the power is 700W; the interaction form between the electromagnetic field and each interface is solved by wave functions, and the various energy conversion paths are calculated based on Joule heat.

[0012] Preferably, step S3 includes: S3.1, using the solver provided by the COMSOL multi-physical field simulation platform to solve, using the 'time-varying' solver to solve the plasma chemical reaction field and realizing dynamic diagnosis and detection, using the automatic distribution strategy built-in COMSOL to control the calculation time step, and setting the initial step to 1e-13s; S3.2, using the 'full coupling' solver to realize the simultaneous solving of the internal variables of the physical field, and using a highly nonlinear method combined with a small initial damping to solve and locate the convergence domain; S3.3, using PARDISO or MUMPS solver to solve the discrete variables in each physical field.

[0013] Preferably, step S4 includes: S4.1, the dynamic internal characteristic information of the plasma can be directly obtained according to the requirements of quality and precision in actual production and processing, including the temperature distribution of the plasma at each place, the actual values and distribution of various reaction rates, the spatial distribution of the electromagnetic field; the reaction rate includes the generation rate and distribution of reactive free radicals, the total generation and consumption rate and distribution of electrons S4.2, according to the various information provided by the model, the actual processing and production characteristics of the atmospheric pressure inductively coupled plasma are diagnosed and detected, and then the performance is improved by improving the generator structure and process gas parameters.

[0014] Further, the application also provides an atmospheric pressure inductively coupled plasma characteristic generation device which applies the above-mentioned atmospheric pressure inductively coupled plasma characteristic diagnosis method, and the generation device comprises an inner glass tube and an outer glass tube, the inner glass tube is provided with a processing gas inlet, the outer glass tube is provided with a cooling gas inlet, the bottom outer periphery of the outer glass tube is provided with a coil group, the coil group is connected with a modulator and a radio frequency power supply, and the outer glass tube is also connected with an arc starter.

[0015] Compared with the prior art, the application has the following beneficial effects: The embodiment of the application provides a diagnosis method and a generation device for atmospheric pressure inductively coupled plasma characteristics, which can provide different modeling strategies according to actual user requirements, target precision and required cost, can flexibly balance the diagnosis precision and model running time, meets various requirements such as rapid preliminary optimization in the early stage and fine adjustment and improvement in the later stage, and has the characteristics of convenient setting and wide application field range, and can be flexibly adjusted according to various user requirements; moreover, the time-varying model of the multi-physical field coupling of the fluid field, the heat transfer field, the electromagnetic field and the plasma reaction field can truly describe the internal complex physical behavior of the atmospheric pressure inductively coupled plasma, and the problems of the current contact type, non-contact sensor and macroscopic simplified physical model, such as the inability to precisely diagnose the internal physical characteristics of the plasma, are overcome and solved, not only the strong requirement for further improving the quality and precision in actual production and processing is provided, but also the new generation of process control technology represented by the digital twin can be combined to help the plasma processing field to realize intelligent manufacturing. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiments or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1A structure schematic diagram of a plasma generating device provided by an embodiment of the present application is shown in the figure. Figure 2 A geometric structure of a diagnostic method model and a grid structure schematic diagram thereof provided by an embodiment of the present application are shown in the figures. Figure 3 Distribution simulation data of a gas temperature of plasma at t=0.35s provided by an embodiment of the present application is shown in the figure. Figure 4 Distribution simulation data of a number density of chemically reactive free radicals of plasma at t=0.35s provided by an embodiment of the present application is shown in the figure. Figure 5 Distribution simulation data of an electron temperature of chemically reactive free radicals of plasma at t=0.35s provided by an embodiment of the present application is shown in the figure. Figure 6 Distribution simulation data of an electron density of chemically reactive free radicals of plasma at t=0.35s provided by an embodiment of the present application is shown in the figure. Figure 7 Distribution simulation data of a gas temperature of plasma at t=1s provided by an embodiment of the present application is shown in the figure. Figure 8 Distribution simulation data of a number density of chemically reactive free radicals of plasma at t=1s provided by an embodiment of the present application is shown in the figure. Figure 9 Distribution simulation data of an electron temperature of chemically reactive free radicals of plasma at t=1s provided by an embodiment of the present application is shown in the figure. Figure 10 Distribution simulation data of an electron density of chemically reactive free radicals of plasma at t=1s provided by an embodiment of the present application is shown in the figure. Figure 11 Global temperature distribution simulation data of a generator provided by an embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the following further describes a diagnostic method and a generating device for atmospheric pressure inductively coupled plasma characteristics in combination with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0019] Embodiment 1 The embodiment of the present application provides a diagnostic method for atmospheric pressure inductively coupled plasma characteristics, which comprises the following steps: S1, obtaining structure parameters of a generator, establishing a geometric model and a grid of a numerical model thereof; The geometric model is drawn in the modeling software according to the actual geometric parameters of the generator structure. S2, establish a multi-physical field reaction model; Set the boundary conditions of the fluid field, heat transfer field, electromagnetic field, set the inlet condition, outlet condition and boundary temperature of the model; Define the reaction field of various reactions occurring inside the plasma, and define the multi-physical field to communicate and integrate the data inside the physical field; S3, set the solver parameters and execute the calculation; S4, processing of model results, multi-angle diagnosis and detection of plasma internal characteristics.

[0020] The embodiment of the application provides a method for precisely diagnosing atmospheric pressure inductively coupled plasma characteristics, which can provide different modeling strategies according to actual user needs, target accuracy and required cost, can flexibly balance diagnosis accuracy and model running time, meet various needs such as early rapid preliminary optimization and later fine adjustment and improvement, and has the characteristics of convenient setting and wide application field range, and can be flexibly adjusted according to various user needs. Moreover, the embodiment truly describes the complex physical behavior inside the atmospheric pressure inductively coupled plasma by coupling the time-varying model of the fluid field, heat transfer field, electromagnetic field and plasma reaction field, overcomes and solves the problem that the current contact type, non-contact sensor and macroscopic simplified physical model cannot precisely diagnose the internal physical characteristics of the plasma. Not only does it provide a solid foundation for the strong demand for further improving quality and precision in actual production and processing, but also can be combined with a new generation of process control technology represented by "digital twin" to help the plasma processing field realize intelligent manufacturing.

[0021] Embodiment 2 The embodiment of the application provides a diagnosis method for atmospheric pressure inductively coupled plasma characteristics. The method for precisely diagnosing atmospheric pressure inductively coupled plasma characteristics provided by the embodiment of the application can be realized based on a numerical model which can actually describe the complex physical behavior inside the plasma and is corrected based on experimental measurement results.

[0022] In order to realize accurate and rapid precise diagnosis and detection of atmospheric pressure inductively coupled plasma characteristics, the numerical model provided by the embodiment needs to be modeled and set according to the actual structure of the plasma generator, working condition parameters and actual composition of key plasma chemical reactions.

[0023] Further, the diagnosis method of the embodiment of the application specifically includes the following steps: S1, obtain the structure parameters of the generator, establish a geometric model and a grid of the numerical model thereof S1.1, draw a two-dimensional axisymmetric or three-dimensional geometric model of the generator structure according to the actual geometric parameters of the generator structure in the modeling software; S1.2, match the entire geometric model with unstructured or structured grid; S1.3, grid refinement for the plasma main region and the region where the plasma meets the inner wall of the generator.

[0024] In this embodiment, a two-dimensional axisymmetric model is drawn in the modeling software for rapid diagnosis and detection, and unstructured grid is used to improve the calculation speed.

[0025] Further, the grid refinement is performed for the region where the plasma is mainly present and the plasma sheath region (close to the wall of the generator), and the grid size of 0.2mm can be used.

[0026] S2, establish a multi-physical field reaction model S2.1, set the fluid field boundary conditions: set the inlet conditions of the model according to the process gas composition, flow rate and pressure used in the actual plasma generator; set the outlet conditions of the model according to the processing environment of the generator; S2.2, set the heat transfer field boundary conditions: set the temperature boundary of the model according to the interaction relationship between the generator and the external processing environment (such as cooling surface, heating surface, etc.), especially the gas inlet and outlet parts; S2.3, set the electromagnetic field boundary conditions: define the energy source of the electromagnetic field according to the arrangement form of the coil and electrode inside the generator, the interaction form between the electromagnetic field and each interface, and the various conversion paths of energy; S2.4, define the reaction field of various reactions occurring inside the plasma, including elastic collision reaction and excitation reaction, ionization reaction, de-excitation reaction, recombination reaction, etc. in the inelastic collision reaction, and other chemical reactions caused by the main energy of the plasma after the introduction of other process gases, including but not limited to dissociation reaction, recombination reaction, etc.; S2.5, define the multi-physical field to communicate and integrate the data inside the physical field, so that each calculation result of the numerical model meets the definition and limitation of the physical field.

[0027] S3, set the solver parameters and perform calculation S3.1, use the solver provided by COMSOL multi-physical field simulation platform to solve, in order to solve the plasma chemical reaction field and realize dynamic diagnosis and detection, use 'time-varying' solver to solve the plasma chemical reaction field and realize dynamic diagnosis and detection, the physical time required can be flexibly set according to the demand; The calculation time step is controlled by the automatic allocation strategy built in COMSOL, and the initial step is set to 1e-13s; In this embodiment, the time step should be as small as possible to improve the calculation convergence, but if the internal variables of the multi-physical field are few and the convergence of the solution is good, the calculation time step can be appropriately increased to improve the calculation speed.

[0028] S3.2, for the plasma multi-physical field calculation model, the 'full coupling' solver is used to realize the simultaneous solution of the internal variables of the physical field, which can improve the calculation convergence, and the highly nonlinear method combined with small initial damping is used to solve, which can quickly locate the convergence domain; S3.3, the discrete variables in each physical field are solved by PARDISO or MUMPS solver, which can realize the balance of solution accuracy and speed.

[0029] S4, processing of model results, multi-angle diagnosis and detection of internal characteristics of plasma S4.1, according to the demand of quality and precision in actual production and processing, the dynamic internal characteristic information of plasma can be directly obtained, which can be located at any geometric position and physical time in the model, including but not limited to temperature distribution of plasma at each place, actual value and distribution of various reaction rates, spatial distribution of electromagnetic field, etc. Reaction rate includes the generation rate and distribution of reactive free radicals, the total generation and consumption rate and distribution of electrons; S4.2, according to the various information provided by the model, the actual processing and production characteristics of atmospheric pressure inductively coupled plasma are diagnosed and detected, and then the performance is further improved by improving the generator structure and process gas parameters.

[0030] Embodiment 3 The embodiment of the present application provides a diagnosis method for the characteristics of atmospheric pressure inductively coupled plasma. Since the characteristic diagnosis method provided by the present application has multiple application scenarios, the embodiment takes the use of pure argon as process gas and the use of typical plasma generator structure design as an example to illustrate the specific working process steps as follows: S1, obtain the generator structure parameters, establish the geometric model and the grid of the numerical model As determined by the generation mechanism of atmospheric pressure inductively coupled plasma, most plasma generation structures have similar structures. Therefore, the typical structure of the atmospheric pressure inductively coupled plasma generation device used in this embodiment is as shown in the figure. Figure 1

[0031] S1.1, draw the two-dimensional axisymmetric geometric model of the generator structure according to the actual geometric parameters of the generator structure in the modeling software; S1.2, match the triangular structure type grid with the entire geometric model, the grid growth rate of the geometric model is 1.05, and the overall grid size is about 0.5mm~2mm; ​S1.3, the grid size of the grid encryption of the plasma main body region and the plasma and the inner wall of the generator interface region is about 0.2mm, and the final grid structure is as shown in Figure 2

[0032] S2, based on COMSOL software, a multi-physical field reaction model is established S2.1, setting the boundary conditions of the fluid field: setting the inlet conditions of the model according to the actual process gas argon used by the plasma generator, the actual flow rate (inside: 1.5L / min; outside: 12L / min) and pressure (atmospheric pressure environment) etc.; setting the outlet conditions of the model according to the atmospheric pressure processing environment of the generator.

[0033] S2.2, setting the boundary conditions of the heat transfer field: according to the interaction relationship between the generator and the external processing environment, the coil inside is cooled, and the generator outside is naturally convected with the atmospheric environment; setting various temperature boundaries of the model, and the gas inlet and outlet temperatures are both given as 300K.

[0034] S2-3, setting the boundary conditions of the electromagnetic field: defining the energy source of the electromagnetic field according to the arrangement form of the coil and the electrode inside the generator, which is defined as the coil group; frequency: 13.56MHz; power: 700W; defining the interaction form between the electromagnetic field and each interface through wave function for solving, and calculating the various conversion paths of energy based on Joule heat, etc.

[0035] S2.4, defining the reaction field of various reactions occurring inside the atmospheric pressure argon plasma, including elastic collision reaction and excitation reaction, ionization reaction, de-excitation reaction in inelastic collision reaction, etc., to describe the conversion of argon atoms into excited argon atoms, argon ions and ground state, as shown in the following table.

[0036] Table 1 Various plasma reactions considered in this embodiment

[0037] S2.5, defining the multi-physical field to communicate and integrate the data inside each physical field, calculating the plasma conductivity and energy conversion relationship through the coupling of the electromagnetic field and the plasma reaction field, so that each calculation result of the numerical model meets the definition and limitation of all the above physical fields.

[0038] S3, setting the solver parameters and performing calculation ​S3.1, the solver provided by COMSOL multi-physics simulation platform is used for illustration. The 'time-varying' solver is used to solve the plasma chemical reaction field and realize dynamic diagnosis and detection, and the calculation time step is controlled by the automatic allocation strategy built in COMSOL, but the initial step is set to 1e-13s.

[0039] S3.2, the 'full coupling' solver is used to realize the simultaneous solution of the internal variables of the above-mentioned physical fields to improve the calculation convergence, and a highly nonlinear method combined with a small initial damping (1e-6) is used to solve to quickly locate the convergence domain.

[0040] S3.3, the discrete variables in each physical field are solved by using solvers such as PARDISO, which can balance the accuracy and speed of the solution.

[0041] S4, verification of the model, result processing and multi-angle precise diagnosis of the internal characteristics of the plasma S4.1, the model of the embodiment measures the density change of the plasma core position by the least interference optical sensor scheme (continuous high-speed shooting of high-speed CCD camera) to the plasma state, and after comparing with the diagnosis results of the method, it is found that there is periodic fluctuation phenomenon and the deviation between the model diagnosis results and the camera measurement results is less than 5%.

[0042] S4.2, considering that the dynamic internal characteristic information of the plasma in actual production and processing, such as gas temperature, chemical reaction active radical number density, electron temperature and its number density, is very concerned. This part demonstrates with the above data as an example, as shown in Figures 3-10 , respectively show the distribution data at t=0.35s and t=1s.

[0043] S4.3, according to the various information provided by the model of the embodiment, not only can the actual processing and production characteristics of atmospheric pressure inductively coupled plasma be precisely diagnosed and detected, as shown in Figure 11 , but also the generator structure heat dissipation can be improved through the global temperature distribution of the generator, and the process gas parameters can be optimized according to the distribution of the chemical reaction active radical, so as to realize further process performance improvement.

[0044] Further, compared with the current mainstream atmospheric pressure inductively coupled plasma diagnostic technology, the method of the present application does not produce problems similar to the interference of the contact diagnostic method on the state of the plasma itself, has higher spatial resolution than the non-contact diagnostic method, is not affected by the optical measurement path integral, has a larger spatial measurement range, and has higher diagnostic accuracy than simple macroscopic physical models. The present application is a new method for precise diagnosis of plasma characteristics by truly describing various complex physical behaviors inside the plasma, and is an important part of realizing a new generation of intelligent manufacturing control systems.

[0045] Embodiment 4 Further, as shown in Figure 1 The atmospheric pressure inductively coupled plasma characteristic generating device provided by the embodiment of the present application applies the above-mentioned atmospheric pressure inductively coupled plasma characteristic diagnostic method, and includes an inner glass tube 1 and an outer glass tube 2. The inner glass tube 1 is provided with a process gas inlet, and the outer glass tube 2 is provided with a cooling gas inlet. The bottom outer periphery of the outer glass tube 2 is provided with a coil group 3. The coil group 3 is connected with a modulator 4 and a radio frequency power supply 5. The outer glass tube 2 is also connected with an arc starter 6.

[0046] In order to solve the problems in the current mainstream plasma characteristic diagnostic technology, such as the interference of the contact sensor with the actual characteristics of the plasma, the lack of precise resolution capability in the space range of the plasma for the non-contact sensor, and the lack of precise diagnosis of the complex physical behaviors inside the plasma for the macroscopic simplified physical model, the present application provides a method suitable for atmospheric pressure inductively coupled plasma, which can be used in various working conditions, truly describes various complex physical behaviors inside the plasma, and thus realizes precise diagnosis of various plasma characteristics. According to actual needs of users, target accuracy and required costs, the present application can provide different modeling strategies, can flexibly balance diagnostic accuracy and model running time, meets various needs such as rapid preliminary optimization in the early stage and fine adjustment and improvement in the later stage, and the model can predict / diagnose various properties of the plasma, especially various reaction rates and spatial distributions of reaction products that cannot be directly measured by sensors, and can be flexibly applied to various generators. Moreover, the dynamic diagnostic model has the characteristics of convenient setting and wide application field range, and can be flexibly adjusted according to various needs of users. The dynamic diagnostic model of the present application has the characteristics of convenient setting and wide application field range, and has the functions of assisting in structure design optimization of the plasma generator, multi-objective optimization design of working conditions including gas parameters and power parameters, and the like.

[0047] Moreover, the embodiment of the present application truly describes the complex physical behavior inside the atmospheric pressure inductively coupled plasma by coupling the time-varying model of the fluid field, the heat transfer field, the electromagnetic field and the plasma reaction field and the like, overcomes and solves the problem that the current contact type, non-contact sensor and macroscopic simplified physical model cannot precisely diagnose the internal physical characteristics of the plasma, not only provides a solid foundation for the strong demand of further improving the quality and precision in actual production and processing, but also can be combined with a new generation of process control technology represented by digital twin to help the intelligent manufacturing of the plasma processing field. Moreover, the precise diagnosis and detection method of the present application has extremely flexible input parameters and a variety of diagnostic results based on the numerical model, can be applied to the rapid and fine diagnosis of various production and processing in the atmospheric pressure inductively coupled plasma technology scene, realizes fine control, and at the same time has the basic conditions of building a new generation of digital twin system combined with the actual production parameters.

[0048] In the description of the present application, it should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0049] In addition, in the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0050] The above only describes the preferred embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A diagnostic method for the characteristics of atmospheric pressure inductively coupled plasma, characterized in that, Includes the following steps: S1. Obtain the structural parameters of the generator, and establish the geometric model and the mesh of its numerical model; Draw a geometric model in the modeling software based on the actual geometric parameters of the generator structure; S2. Establish a multiphysics response model; Set the boundary conditions for the fluid field, heat transfer field, and electromagnetic field; set the inlet conditions, outlet conditions, and boundary temperatures of the model. Define the reaction fields of various reactions occurring inside the plasma, and define multiphysics fields to communicate and integrate data within the physical fields; S3. Set the solver parameters and execute the calculation; S4. Processing of model results: multi-angle diagnosis and detection of plasma internal characteristics.

2. The diagnostic method for atmospheric pressure inductively coupled plasma characteristics according to claim 1, characterized in that, Step S1 includes: S1.1 Draw a two-dimensional axisymmetric or three-dimensional geometric model of the generator structure in the modeling software based on the actual geometric parameters of the generator structure; S1.

2. Match the entire geometric model with either an unstructured mesh or a structured mesh; S1.

3. Refine the mesh in the main plasma region and the boundary region between the plasma and the inner wall of the generator.

3. The diagnostic method for atmospheric pressure inductively coupled plasma characteristics according to claim 2, characterized in that, The mesh growth rate for establishing the geometric model is 1.05, the overall mesh size is 0.5mm~2mm, and the fine mesh size is 0.2mm.

4. The diagnostic method for atmospheric pressure inductively coupled plasma characteristics according to claim 1, characterized in that, Step S2 includes: S2.1 Setting fluid field boundary conditions: Set the inlet conditions of the model according to the process gas composition, flow rate and pressure used in the actual plasma generator; set the outlet conditions of the model according to the processing environment in which the generator is located. S2.2 Setting heat transfer field boundary conditions: Set the temperature boundary of the model according to the interaction between the generator and the external processing environment; S2.3 Setting electromagnetic field boundary conditions: Define the energy source of the electromagnetic field, the interaction between the electromagnetic field and each interface, and the various energy conversion paths according to the arrangement of the coils and electrodes inside the generator; S2.4 Define the reaction field of various reactions occurring inside the plasma, including excitation reactions, ionization reactions, de-excitation reactions, and recombination reactions in elastic and inelastic collision reactions, as well as chemical reactions, dissociation reactions, and recombination reactions caused by the plasma's main energy after the introduction of other process gases. S2.

5. Define multiphysics to communicate and integrate data within the physical field, so that each calculation result of the numerical model satisfies the definition and constraints of the physical field.

5. The diagnostic method for atmospheric pressure inductively coupled plasma characteristics according to claim 4, characterized in that, When setting the boundary conditions of the heat transfer field, the generator coil is cooled inside, and the generator is cooled by natural convection with the atmospheric environment outside; the gas inlet and outlet temperatures are both 300K.

6. The diagnostic method for atmospheric pressure inductively coupled plasma characteristics according to claim 4, characterized in that, When setting the electromagnetic field boundary conditions, the energy source of the electromagnetic field is defined according to the arrangement of the coils and electrodes inside the generator. The coil group parameters are defined as follows: frequency: 13.56MHz, power: 700W. The interaction between the electromagnetic field and each interface is defined and solved by wave function. Various energy conversion paths are calculated based on Joule heating.

7. The diagnostic method for atmospheric pressure inductively coupled plasma characteristics according to claim 1, characterized in that, Step S3 includes: S3.1 The solver provided by the COMSOL multiphysics simulation platform is used to solve the plasma chemical reaction field and realize dynamic diagnosis and detection. The calculation time step is controlled by the automatic allocation strategy built into COMSOL, and the initial step is set to 1e-13s. S3.

2. A fully coupled solver is used to solve the internal variables of the physical field simultaneously. At the same time, a highly nonlinear method is used in combination with a small initial damping to solve the problem and locate the region of convergence. S3.3 The discrete variables in each physical field are solved using PARDISO or MUMPS solvers.

8. The diagnostic method for atmospheric pressure inductively coupled plasma characteristics according to claim 1, characterized in that, Step S4 includes: S4.

1. Based on the quality and precision requirements in actual production and processing, the dynamic internal characteristics of the plasma can be directly obtained, including the temperature distribution at various points in the plasma, the actual values ​​and distributions of various reaction rates, and the spatial distribution of the electromagnetic field; the reaction rates include the generation rate and distribution of reactive free radicals, and the total generation and consumption rate and distribution of electrons. S4.2 Based on the various information provided by the model, the actual processing and production characteristics of atmospheric pressure inductively coupled plasma are diagnosed and tested, and then its performance is improved by improving the generator structure and process gas parameters.

9. An atmospheric pressure inductively coupled plasma characteristic generator, characterized in that, The method for diagnosing the characteristics of atmospheric pressure inductively coupled plasma as described in any one of claims 1-8, wherein the generating device includes an inner glass tube and an outer glass tube, the inner glass tube is provided with a processing gas inlet, the outer glass tube is provided with a cooling gas inlet, a coil group is provided on the bottom outer periphery of the outer glass tube, a modulator and a radio frequency power supply are connected to the coil group, and an arc initiator is also connected to the outer glass tube.

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