Multi-medium gas flow in-situ calibration method and system for semiconductor technology

Abstract

The invention relates to the field of flowmeter measurement, in particular to a multi-medium gas flow in-situ calibration method and system for a semiconductor process, and the method comprises the following steps: a database building step: building a sound velocity-volume fraction database of each component; a calibration data acquisition step: acquiring real-time environment parameters and sound velocity data; a gas component analysis step: obtaining volume fraction data of each component according to the real-time sound velocity value; a flow meter calibration step: calculating the flow value of each component based on the volume fraction data of each component, and calibrating the flow meter according to the flow value; by adding sound velocity measurement and constructing a corresponding sound velocity-volume fraction database, the mixing proportion of each gas medium in the mixed gas can be quickly obtained, so that the flow measurement of the mixed gas consisting of multiple media in a semiconductor process scene is realized; and the calibration efficiency of a gas medium related process in the semiconductor manufacturing field is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor process manufacturing, and particularly relates to a multi-medium gas flow in-situ calibration method and system for semiconductor process. BACKGROUND

[0002] In the field of semiconductor manufacturing, gas media play an irreplaceable role in many key processes. For example, in etching process, by precisely controlling the flow of gas containing specific gas (such as fluorine-based gas), the specific part of semiconductor material can be accurately removed according to the design requirements, so as to realize the complex chip pattern making; in chemical vapor deposition process, different gases are mixed in precise proportion and the flow is controlled, and high-quality thin films are deposited on the semiconductor substrate, which are the basis of various functional structures inside the chip. It can be said that the precise control of gas medium flow is directly related to the quality, performance and yield of semiconductor products, and has a profound impact on the development of the entire semiconductor manufacturing industry.

[0003] At present, mass flow controller (MFC) is the core equipment to realize the precise control of gas flow. However, due to the variety of gas media involved in semiconductor manufacturing, covering inert gas, corrosive gas, reactive gas, etc., and the great difference in physical and chemical properties of different gases, for example, hydrogen is flammable and explosive, nitrogen trifluoride has strong oxidizing property. These characteristics make the internal sensing elements, flow regulating components, etc. of the mass flow controller susceptible to erosion, contamination by gas or performance drift due to changes in working conditions, thereby leading to the decrease of the accuracy of flow measurement and control. In order to ensure that the mass flow controller can provide accurate flow control continuously and stably, the calibration work at irregular intervals is crucial.

[0004] From the calibration mode, at present, the calibration of most mass flow controllers adopts the laboratory calibration mode of disassembling and sending for inspection. This mode needs to disassemble the mass flow controller from the semiconductor manufacturing production line, transport it to the professional laboratory for calibration, which not only consumes a lot of time and labor cost, but also causes the shutdown of the semiconductor manufacturing process, seriously affecting the production efficiency. Especially in modern large-scale semiconductor production, the continuity of the production line is crucial, and frequent shutdown calibration will cause huge economic losses. Therefore, in-situ calibration on the semiconductor manufacturing process flow has become an urgent demand in the industry. In the field of in-situ calibration technology, only the MKS company in the United States has mastered the relevant technology. However, the in-situ calibration technology of the company has obvious limitations, and it can only meet the flow calibration needs of a single medium. However, in the process of semiconductor processing and manufacturing, such as etching, doping, chemical vapor deposition, annealing heat treatment and cleaning, etc. Key processes often require the use of mixed gas composed of multiple media. For example, etching process may use mixed gas containing chlorine, nitrogen trifluoride and argon. Different gases play different roles in the etching process. Chlorine is used for chemical etching, nitrogen trifluoride enhances etching effect, and argon assists in controlling etching rate and direction. However, the technology of MKS company cannot accurately measure and calibrate the flow and composition of such mixed gas, which is difficult to meet the stringent requirements of semiconductor manufacturing process for accurate control of gas flow, which undoubtedly becomes a bottleneck restricting the further development of semiconductor manufacturing technology.

[0005] Therefore, in order to solve the problems existing in the prior art, the present application provides a method and system capable of in-situ calibration of multi-medium gas flow, which has important practical significance for improving the accuracy and efficiency of gas flow control in the field of semiconductor manufacturing and promoting the development of the semiconductor industry. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a multi-medium gas flow in-situ calibration method and system for semiconductor process To achieve the above-mentioned purpose, the present application provides the following technical solutions: A multi-medium gas flow in-situ calibration method for semiconductor process, comprising the following steps: A database building step, obtaining standard environmental parameters in the in-situ calibration device, the standard environmental parameters including standard temperature data and standard pressure data, and constructing a sound speed-volume fraction database of each component in the mixed gas under standard environment according to the standard environmental parameters; A calibration data acquisition step, measuring real-time environmental parameters and measuring real-time sound speed data of the mixed gas, and timestamping the real-time environmental parameters and real-time sound speed data to the same instant; The gas component analysis step maps the real-time sound velocity data to the sound velocity-volume fraction database of the mixed gas under the standard environment according to the real-time environmental parameter to obtain the closest sound velocity value, and obtains the volume fraction data of each component gas in the mixed gas according to the closest sound velocity value; The flow calculation calibration step calculates the volume flow of the mixed gas under the standard condition based on the ideal gas state equation, and calculates the flow value of each component according to the volume fraction data of each component in the mixed gas, to calibrate the corresponding flow meter.

[0007] As a further improvement of the application, the database building step includes constructing a gas sound velocity calculation model under the standard environment by the equivalent specific heat ratio of the mixed gas, the temperature of the mixed gas and the average molar mass of the mixed gas, and traversing the molar mass of each component gas and the volume fraction value of each component gas from the single medium gas property table according to the average molar mass of the mixed gas to obtain the sound velocity-volume fraction database under the sound velocity of the gas.

[0008] As a further improvement of the application, the gas component analysis step further includes converting the real-time environmental parameter through an environmental parameter conversion strategy, calculating a sound velocity adjustment factor according to the difference between the real-time environmental parameter and the standard environmental parameter and the adjustment factor of the mixed gas of different components, and calculating a mapping sound velocity value as the closest sound velocity value in the sound velocity-volume fraction database of the mixed gas under the standard environment from the real-time sound velocity data through the sound velocity adjustment factor, to obtain the volume fraction data of each component gas through the mapping sound velocity value.

[0009] As a further improvement of the application, the sound velocity calculation model is configured with:

[0010] wherein c is the sound velocity value under the standard environment, k is the equivalent specific heat ratio of the mixed gas, R is the universal gas constant, T is the temperature of the mixed gas, and M is the average molar mass of the mixed gas, wherein, , i represents the i-th component gas of the mixed gas, n is the total number of component gases, k i is the specific heat capacity ratio of the i-th component gas, M i is the molar mass of the i-th component gas.

[0011] As a further improvement of the application, the flow calculation calibration step includes calculating the total volume flow of the mixed gas under the standard environment based on the ideal gas state equation through the real-time collected pressure data and temperature data, and the average molar mass of the mixed gas, and calculating the flow value of each component gas through the gas fraction data of each component gas and the total volume flow.

[0012] As a further improvement of the present application, the total volume flow value calculation configuration is provided with:

[0013]

[0014] wherein Q is the total volume flow value, V is the volume of the fixed volume chamber, p is the average density of the mixed gas under standard environment, , V m is the molar volume of the mixed gas under standard environment, is the rate of pressure change per unit time, Q i is the flow value of each component gas.

[0015] As a further improvement of the present application, the flow calculation calibration step further comprises comparing the individual flow value of each gas medium with the preset flow value of the flow meter, and when the deviation exceeds the preset threshold value, adjusting the output parameter of the flow meter to the measured flow value and the preset value through the PID control algorithm.

[0016] A multi-medium gas flow in-situ calibration system for semiconductor process, comprising: A database building module acquires standard environment parameters in the in-situ calibration device, the standard environment parameters including standard temperature data and standard pressure data, and builds a sound speed-volume fraction database of each component in the mixed gas under standard environment according to the standard environment parameters; A calibration data acquisition module measures real-time environment parameters and measures real-time sound speed data of the mixed gas, and timestamps the real-time environment parameters and real-time sound speed data to the same instant; A gas composition analysis module maps the real-time sound speed data to the sound speed-volume fraction database of the mixed gas under standard environment according to the real-time environment parameters to obtain the closest sound speed value, and obtains the volume fraction data of each component gas in the mixed gas according to the closest sound speed value; A flow calculation calibration module calculates the volume flow of the mixed gas under standard conditions based on the ideal gas state equation, and calculates the flow value of each component based on the volume fraction data of each component in the mixed gas, and calibrates the corresponding flow meter.

[0017] As a further improvement of the present application, a multi-medium gas flow in-situ calibration system for semiconductor process further comprises: A temperature sensor located in the calibration cavity for collecting temperature data of the mixed gas in the cavity; A pressure sensor located at the outlet end of the calibration cavity for collecting pressure data of the mixed gas in the cavity; A sound velocity meter is arranged in the calibration cavity in an axial direction to measure the sound velocity propagation time of the mixed gas and convert the sound velocity data.

[0018] As a further improvement of the present application, the temperature sensor, pressure sensor and sound velocity meter are arranged to receive the same synchronization signal in each data acquisition cycle, to calibrate the time stamps of the acquired temperature data, pressure data and sound velocity data to the same instant.

[0019] The beneficial effects of the present application are: (1) Realize multi-medium mixed gas calibration, break through the limitations of existing technology, and can calibrate the flow measurement of mixed gas composed of multiple media. By constructing a sound velocity-volume fraction database, combined with real-time environmental parameters and sound velocity data, the mixing ratio of each gas medium in the mixed gas can be quickly and accurately obtained, solving the problem of flow calibration of multiple mixed gases in semiconductor manufacturing, meeting the needs of complex processes such as etching and doping, and improving the gas flow control precision of semiconductor manufacturing processes.

[0020] (2) Improve calibration efficiency. Compared with the traditional separate calibration of component gases, the present application only adds sound velocity measurement, which can realize mixed gas flow calibration. A large amount of calibration time is saved, multiple gas media do not need to be calibrated separately, the calibration process and operation steps are reduced, production interruptions caused by frequent calibration are avoided, the calibration efficiency of gas medium related processes in the semiconductor manufacturing field is improved, the continuity of production is ensured, and the production cost is reduced.

[0021] (3) Enhance calibration accuracy. The environmental parameter conversion strategy is used to calculate the sound velocity adjustment factor to calibrate the real-time sound velocity data and eliminate the influence of the difference between the actual environment and the standard environment on the sound velocity measurement. In the flow calculation calibration step, the PID control algorithm is used to dynamically adjust the flow meter to ensure that the measured flow is consistent with the preset value, greatly improving the accuracy of mixed gas volume fraction acquisition and the precision of flow meter calibration, providing accurate gas flow control for semiconductor processes, and thus improving the quality and yield of semiconductor products. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a method flowchart of the present application; Figure 2 is a system workflow schematic diagram in an embodiment of the present application. DETAILED DESCRIPTION

[0023] The application will be further described in detail below in combination with the drawings and embodiments. Identical parts are denoted by identical reference numerals. It should be noted that the words "front", "back", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings, and the words "bottom surface" and "top surface", "inner" and "outer" refer to the directions towards or away from the geometric center of a particular part.

[0024] The current prior art can only meet the flow calibration requirements of a single medium and cannot be applied to the flow and component metering calibration of mixed gas, and cannot meet the demand for accurate measurement of the flow of mixed gas composed of multiple media in the semiconductor processing and manufacturing process. Therefore, the embodiments of the present application propose a multi-medium gas flow in-situ calibration method for semiconductor processes, as shown in Figure 1 The method comprises the following steps: A database building step acquires standard environmental parameters in the in-situ calibration device, the standard environmental parameters including standard temperature data and standard pressure data, and a sound speed-volume fraction database of each component in the mixed gas under a standard environment is constructed according to the standard environmental parameters; In a semiconductor process environment, the sound speed characteristics of a gas are affected by multiple factors such as temperature and pressure. Therefore, in order to accurately calibrate the gas flow subsequently, a standard environmental parameter is needed to measure a set of fixed temperature data and pressure data as standard temperature data and standard pressure data. The standard environment is determined according to the working conditions of the semiconductor process, for example, when the standard temperature is 25 degrees, the standard pressure is set to 1 standard atmosphere.

[0025] When building the sound speed-volume fraction database, a large number of sound speed measurement experiments are performed on mixed gases with different volume fractions, and exhaustive experiments are performed by configuring gas samples with different volume proportions to obtain the corresponding relationship between the volume fraction and the sound speed value of the component gas accurately measured under the standard environment, and these corresponding data are recorded in the database. In this way, a comprehensive and accurate sound speed-volume fraction corresponding relationship database is constructed to provide a reliable reference for subsequent multi-flow meter calibration work.

[0026] Specifically, the database building step comprises building a gas sound speed calculation model under a standard environment by the equivalent specific heat capacity ratio of the mixed gas, the mixed gas temperature and the average molar mass of the mixed gas, and according to the average molar mass of the mixed gas, the molar mass of each component gas and the volume fraction value of each component gas are queried from the single medium gas property table to obtain the sound speed-volume fraction database under the gas sound speed.

[0027] Specifically, the sound speed calculation model is configured with:

[0028] wherein c is the sound speed value in the standard environment, k is the equivalent specific heat capacity ratio of the mixed gas, reflecting the thermal characteristics of the gas molecules, which is related to the specific heat capacity ratio k i related to the volume fraction of the gas molecules, R is the universal gas constant, T is the temperature of the mixed gas, which is a specific value set according to the specific working conditions in different processes in the standard environment, and M is the average molar mass of the mixed gas, which reflects the molar mass M i and the proportion thereof, wherein, , , i represents the i-th component gas of the mixed gas, n is the total number of component gases, k i is the specific heat capacity ratio of the i-th component gas, M i is the molar mass of the i-th component gas.

[0029] After obtaining the sound speed calculation model, the average molar mass of the mixed gas is obtained, and the single medium gas property table is traversed according to the average molar mass. For example, in the database containing numerous gas property parameters, the average molar mass of the mixed gas is input, the system will automatically match the molar mass of each component gas, and combine the previously set or measured volume fraction values of each component gas to record the corresponding sound speed values at each different volume fraction, and gradually build a comprehensive sound speed-volume fraction database. The database covers the sound speed data under various combinations of gas component proportions, providing rich and accurate references for subsequent calibration work.

[0030] The calibration data acquisition step measures the real-time environmental parameters and the real-time sound speed data of the mixed gas, and timestamps the real-time environmental parameters and the real-time sound speed data to the same instant; In actual semiconductor process operation, the environmental parameters will change constantly, so it is necessary to measure the environmental parameters in real time, and to measure the real-time sound speed data of the mixed gas. Due to the time difference between the collection of real-time environmental parameters and real-time sound speed data, when there is a time difference, it is impossible to accurately measure the data under real-time conditions, so it is necessary to perform timestamp calibration to calibrate each data to the same instant.

[0031] The gas composition analysis step maps the real-time sound speed data to the closest sound speed value in the sound speed-volume fraction database of the mixed gas in the standard environment according to the real-time environmental parameters, and obtains the volume fraction data of each component gas in the corresponding mixed gas according to the closest sound speed value; After obtaining the calibrated real-time environmental parameters and real-time sound speed data, the real-time sound speed data needs to be processed according to the real-time environmental parameters. Since we have previously constructed a sound speed-volume fraction database of mixed gas under standard environment, the real-time sound speed data can be mapped into the database at this time to find the closest sound speed value. In the mapping process, the difference degree of the real-time sound speed and each sound speed value in the database is calculated by the algorithm of the application, and the real-time sound speed value is mapped and converted into the sound speed value in the sound speed-volume fraction database under the standard environment according to the difference degree, and the corresponding volume fraction data of each component gas in the mixed gas is obtained according to the record corresponding to the sound speed value in the database. In this way, the sound speed value measured under different gas environments is converted to the standard environment for volume fraction data corresponding mode, avoiding the repeated establishment of sound speed-volume fraction databases under different environmental parameters, reducing the workload of database construction, and improving the volume fraction measurement efficiency; and by mapping and calibrating the sound speed values under different environmental parameters with the sound speed values under the standard environment, the accuracy of obtaining the volume fraction of the mixed gas can be increased.

[0032] Specifically, the gas component analysis step further comprises calculating a sound speed adjustment factor according to the difference between the real-time environmental parameters and the standard environmental parameters and the adjustment factor of the mixed gas of different components through an environmental parameter conversion strategy, and calculating a mapping sound speed value as the closest sound speed value in the sound speed-volume fraction database of the mixed gas under the standard environment through the sound speed adjustment factor and the real-time sound speed data, and obtaining the volume fraction data of each component gas through the mapping sound speed value.

[0033] For example, in a certain semiconductor etching process, the standard environmental parameters are set as temperature data of 298K, pressure data of 101.3kPa, the real-time environmental parameters are measured by sensors, the real-time temperature data is 303K, the pressure is 101.3kPa, the component gases of the mixed gas are nitrogen trifluoride and argon, and the adjustment factors of the two gases to the environmental parameter changes are known. The corresponding relationship between the data difference and the adjustment factor is that the temperature adjustment factor of nitrogen trifluoride (NF3) is 0.005K, the pressure adjustment factor is 0.1kPa, the temperature adjustment factor of argon (Ar) is 0.005K, and the pressure adjustment factor is 0.1kPa. First, the influence of each component gas on the environment change is calculated according to the difference between the real-time environmental parameters and the standard environmental parameters. For the temperature, the influence amount of NF3 is 0.005K, and the influence amount of Ar is 0.005K. For the pressure, the influence amount of NF3 is 0.1kPa, and the influence amount of Ar is 0.1kPa. ​​​​​​​​​​The influence amount of Ar The sound speed adjustment factor of the mixed gas is calculated, and the mapped sound speed value is calculated by multiplying the sound speed adjustment factor with the real-time sound speed data Wherein, x NF3 is the volume fraction of NF3, x Ar is the volume fraction of Ar, and the mapped sound speed value is calculated by multiplying the sound speed adjustment factor with the real-time sound speed data c real is the real-time sound speed data actually measured. The mapped sound speed value is brought into the sound speed-volume fraction database of the mixed gas under the standard environment, and the sound speed value closest to the sound speed value and the corresponding volume fraction data record are found through data matching. Through such a detailed environmental parameter conversion strategy and calculation process, the influence of the difference between the actual environment and the standard environment on the sound speed measurement can be effectively eliminated, the accuracy of the gas component analysis is improved, and the precision of the entire multi-medium gas flow in-situ calibration method is ensured, meeting the stringent requirements of semiconductor process on precise control of gas flow.

[0034] The flow calculation and calibration step calculates the volume flow of the mixed gas under the standard condition based on the ideal gas state equation, and calculates the flow value of each component according to the volume fraction data of each component in the mixed gas, and calibrates the corresponding flow meter. Through the known real-time pressure, temperature and amount of substance of the mixed gas, the volume flow of the mixed gas under the standard environment (i.e. standard condition) can be calculated, and then the flow value of each component can be calculated according to the volume fraction data of each component in the mixed gas. After obtaining the flow value of each component, it is compared with the measured value of the corresponding flow meter, and the flow meter is calibrated according to the difference, so as to ensure that the flow meter can accurately measure the flow of each component gas, and provide accurate gas flow control for semiconductor process.

[0035] Specifically, the flow calculation and calibration step includes calculating the total volume flow of the mixed gas under the standard environment based on the ideal gas state equation through the real-time collected pressure data and temperature data, and the average molar mass of the mixed gas, and calculating the flow value of each component gas through the gas fraction data of each component gas and the total volume flow.

[0036] Specifically, the total volume flow value is configured as:

[0037]

[0038] Wherein, Q is the total volume flow value, V is the volume of the fixed volume cavity, p is the average density of the mixed gas under the standard environment, V m is the molar volume of the mixed gas under the standard environment, is the rate of pressure change per unit time, Qi Flow value of each component gas.

[0039] Further, the flow calculation calibration step further comprises real-time calibration control logic. The independent flow value (Q i ) of each component gas is compared with the preset flow value of the flow meter, and if the deviation exceeds the preset threshold value (for example, ±2%), the output parameter (such as the opening of the regulating valve or the set value of the mass flow controller) of the flow meter is dynamically adjusted by a PID (proportional-integral-derivative) control algorithm until the measured flow value is consistent with the preset value. The proportional term (K p ), the integral term (K i ), and the derivative term (K d ) parameters of the PID algorithm can be optimized according to actual process requirements to improve the response speed and stability of the system.

[0040] Specifically, the flow calculation calibration step further comprises comparing the independent flow value of each gas medium with the preset flow value of the flow meter, and when the deviation exceeds the preset threshold value, adjusting the output parameter of the flow meter to the measured flow value consistent with the preset value by the PID control algorithm.

[0041] In the flow calculation calibration step, the deviation calibration of the independent flow value of each gas medium is realized by a closed-loop PID (proportional-integral-derivative) control algorithm for dynamic adjustment, and the specific process is as follows: (1) Deviation definition and threshold setting: Let the preset flow value of the i-th component gas be Q i,set , the measured flow value be Q i,meas , and the deviation be defined as: The preset threshold value can be flexibly set according to process requirements, and independent threshold values are configured for different gas media to adapt to the differences in process sensitivity, for example, a more stringent threshold value (1%) is required for corrosive gas, and the threshold value for inert gas can be relaxed to 3% (2) PID control algorithm When the deviation exceeds the threshold value, the PID controller calculates the output adjustment amount ,

[0042] Wherein: The proportional term K p : quickly responds to the current deviation, but may cause overshoot; The integral term K i : eliminates steady-state error, but long integration time will cause system lag; The derivative term K d : predicts future error trends and suppresses oscillations, but is sensitive to noise.

[0043] PID parameters (K p, K i, K d ) need to be optimized through experiments or system identification. For example, the Ziegler-Nichols tuning method is used to ensure that the system converges quickly in a critically stable state.

[0044] (3) Actuator adjustment and feedback verification PID output Actual control signal of flow meter: Control valve control: adjust the valve opening (e.g. 0-100% linear mapping) to change the gas flow cross-sectional area; Mass flow controller (MFC): directly modify the set current or voltage signal to accurately control the flow.

[0045] After adjustment, the system collects the updated flow value in real time and recalculates the deviation. If the deviation is still out of limits, the PID adjustment is iteratively performed until the preset conditions are met or the maximum number of iterations is reached (to prevent entering a dead loop).

[0046] A multi-medium gas flow in-situ calibration system for semiconductor processes, comprising: A database building module acquires standard environmental parameters in the in-situ calibration device, the standard environmental parameters including standard temperature data and standard pressure data, and builds a sound speed-volume fraction database of each component in the mixed gas under standard environment according to the standard environmental parameters; A calibration data acquisition module measures real-time environmental parameters and real-time sound speed data of the mixed gas, and timestamps the real-time environmental parameters and real-time sound speed data to the same instant; A gas composition analysis module maps the real-time sound speed data to the sound speed-volume fraction database of the mixed gas under standard environment according to the real-time environmental parameters to obtain the closest sound speed value, and obtains the volume fraction data of each component gas in the mixed gas according to the closest sound speed value; A flow calculation and calibration module calculates the volume flow of the mixed gas under standard conditions based on the ideal gas state equation, and calculates the flow value of each component based on the volume fraction data of each component in the mixed gas, and calibrates the corresponding flow meter.

[0047] Specifically, a multi-medium gas flow in-situ calibration system for semiconductor processes further comprises: A temperature sensor located in the calibration cavity for collecting temperature data of the mixed gas in the cavity; A pressure sensor located at the outlet end of the calibration cavity for collecting pressure data of the mixed gas in the cavity; A sound velocimeter located in the calibration cavity along the axial direction for measuring the sound speed propagation time of the mixed gas and converting it into sound speed data.

[0048] Specifically, during each data acquisition cycle, the temperature sensor, pressure sensor, and sound velocity meter are set to receive the same synchronization signal to calibrate the timestamps of the acquired temperature data, pressure data, and sound velocity data to the same instant.

[0049] like Figure 2 The diagram shown is a schematic of the device system in this embodiment. When the gas input to the gas source system is N2... When He, HCl, and Ar are present, several gases are introduced into corresponding numbers of MFCs to be calibrated, and then introduced in parallel into the processing chamber and the in-situ calibration device through a critical flow nozzle. The in-situ calibration device includes a critical flow nozzle and a fixed cavity. The fixed cavity is equipped with a temperature sensor and a pressure sensor, and a sound velocity meter is connected to the outlet end. The mixed gas enters the vacuum pump through the processing chamber and the in-situ calibration device to complete the flow rate calculation.

[0050] The foregoing has illustrated and described the basic features, principles, and advantages of the present invention. It should be noted that the present invention is not limited to the above embodiments, but only to some embodiments. Any improvements and additions made without departing from the spirit and scope of the present invention are considered to be within the scope of protection of the present invention.

Claims

1. A method for in-situ calibration of multi-medium gas flow rates in semiconductor processes, characterized in that, Includes the following steps: The database construction steps include obtaining standard environmental parameters from the in-situ calibration device, including standard temperature data and standard pressure data, and constructing a sound velocity-volume fraction database for each component in a mixed gas under standard conditions based on the standard environmental parameters. The calibration data acquisition step involves measuring and acquiring real-time environmental parameters and measuring real-time sound velocity data of the mixed gas, and then calibrating the real-time environmental parameters and real-time sound velocity data to the same instant. The gas composition analysis step involves mapping the real-time sound velocity data to a standard environment mixed gas sound velocity-volume fraction database based on the real-time environmental parameters to obtain the closest sound velocity value, and obtaining the volume fraction data of each component gas in the mixed gas based on the closest sound velocity value. The flow calculation and calibration steps involve calculating the volumetric flow rate of the mixed gas under standard conditions based on the ideal gas law, and calculating the flow rate value of each component based on the volume fraction data of each component in the mixed gas, and calibrating the corresponding flow meter.

2. The in-situ calibration method for multi-dielectric gas flow rates in semiconductor processes according to claim 1, characterized in that, The database construction steps include: constructing a gas sound velocity calculation model under standard conditions using the equivalent specific heat ratio, temperature, and average molar mass of the mixed gas; and querying the molar mass and volume fraction of each component gas by traversing the gas property table of a single medium using the average molar mass of the mixed gas to obtain a sound velocity-volume fraction database for that gas sound velocity.

3. The in-situ calibration method for multi-medium gas flow rate in semiconductor processes according to claim 1, characterized in that, The gas composition analysis step further includes: using an environmental parameter conversion strategy, calculating a sound velocity adjustment factor based on the difference between the real-time environmental parameters and the standard environmental parameters, as well as the adjustment factors of the mixed gas with different components; calculating a mapped sound velocity value using the sound velocity adjustment factor and the real-time sound velocity data, which is the sound velocity value closest to the real-time sound velocity data in the sound velocity-volume fraction database of the mixed gas under standard conditions; and obtaining the volume fraction data of each component gas using the mapped sound velocity value.

4. The in-situ calibration method for multi-dielectric gas flow rate in a conductor process according to claim 2, characterized in that, The sound speed calculation model is configured with: ； Where c is the speed of sound under standard conditions, k is the equivalent specific heat ratio of the gas mixture, R is the universal gas constant, T is the temperature of the gas mixture, and M is the average molar mass of the gas mixture. , Let i represent the component gas in the i-th gas mixture, n be the total number of component gases, and k be the component gas. i Let M be the specific heat ratio of the i-th component gas. i Let be the molar mass of the i-th component gas.

5. The in-situ calibration method for multi-dielectric gas flow rates in semiconductor processes according to claim 1, characterized in that, The flow calculation calibration step includes calculating the total volumetric flow rate of the mixed gas under standard conditions based on the ideal gas law using real-time collected pressure and temperature data and the average molar mass of the mixed gas, and calculating the flow rate value of each component gas using the gas fraction data of each component gas and the total volumetric flow rate.

6. The in-situ calibration method for multi-dielectric gas flow rates in semiconductor processes according to claim 5, characterized in that, The total volumetric flow rate calculation configuration includes: Where Q is the total volumetric flow rate, V is the volume of the fixed cavity, and ρ is the average density of the gas mixture under standard conditions. V m The molar volume of the gas mixture under standard conditions. Q is the rate of pressure change per unit time. i These represent the flow rates of each component gas.

7. The in-situ calibration method for multi-dielectric gas flow rates in semiconductor processes according to claim 1, characterized in that, The flow calculation calibration step also includes comparing the independent flow values ​​of each gas medium with the preset flow value of the flow meter. If the deviation exceeds the preset threshold, the output parameters of the flow meter are adjusted by a PID control algorithm until the measured flow rate is consistent with the preset value.

8. A multi-medium gas flow rate in-situ calibration system for semiconductor processes, applicable to the multi-medium gas flow rate in-situ calibration method for semiconductor processes as described in any one of claims 1 to 7, characterized in that, include: The database construction module acquires standard environmental parameters from the in-situ calibration device. These standard environmental parameters include standard temperature data and standard pressure data. Based on these standard environmental parameters, a sound velocity-volume fraction database of each component in a mixed gas under standard conditions is constructed. The calibration data acquisition module measures and acquires real-time environmental parameters and measures real-time sound velocity data of the mixed gas, and timestamps and calibrates the real-time environmental parameters and real-time sound velocity data to the same instant. The gas composition analysis module maps the real-time sound velocity data to a standard environment mixed gas sound velocity-volume fraction database based on the real-time environmental parameters to obtain the closest sound velocity value, and obtains the volume fraction data of each component gas in the mixed gas based on the closest sound velocity value. The flow calculation and calibration module calculates the volumetric flow rate of the mixed gas under standard conditions based on the ideal gas law, and calculates the flow rate value of each component based on the volume fraction data of each component in the mixed gas, and calibrates the corresponding flow meter.

9. A multi-medium gas flow in-situ calibration system for semiconductor processes according to claim 8, characterized in that, Also includes: A temperature sensor, located inside the calibration chamber, is used to collect temperature data of the mixed gas inside the chamber. A pressure sensor, located at the outlet of the calibration chamber, is used to collect pressure data of the mixed gas inside the chamber; The sound velocity meter, located axially within the calibration chamber, is used to measure the propagation time of sound in the gas mixture and convert it into sound velocity data.

10. A multi-medium gas flow in-situ calibration system for semiconductor processes according to claim 9, characterized in that, During each data acquisition cycle, the temperature sensor, pressure sensor, and sound velocity meter are set to receive the same synchronization signal to calibrate the timestamps of the acquired temperature data, pressure data, and sound velocity data to the same instant.

Images