Electrothermal adsorption type tail gas treatment equipment for RPS dissociation rate test

Abstract

The invention discloses electrothermal adsorption type tail gas treatment equipment for RPS dissociation rate testing in the field of remote plasma sources. The electrothermal adsorption type tail gas treatment equipment comprises a heating system, a water vapor injection system, a cooling system and an adsorption system which are communicated in sequence, the heating system comprises a sectional reaction tube, and the temperature field of the sectional reaction tube is distributed progressively from the gas inlet end to the gas outlet end; the adsorption system comprises a first-stage solid adsorption layer and a second-stage circulating spraying system, the sectional type reaction tube is of a three-section coaxial nested structure and comprises a preheating section, a main decomposition section and a deep cracking section, and each section independently controls the temperature and is heated through a high-frequency induction coil. According to the electric heating adsorption type tail gas treatment equipment, step-by-step decomposition of NF3 is achieved through sectional heating, harmful gas (such as HF) is efficiently neutralized in combination with a multi-stage adsorption system, harmful substances in tail gas can be effectively removed, and environmental pollution is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of remote plasma sources, and particularly to an electrothermal adsorption type tail gas treatment device for RPS dissociation rate testing. Background Art

[0002] A remote plasma source (RPS) is an advanced plasma generation device, also known as a remote high-density plasma generator, and is commonly used for the cleaning and etching processes of process chambers in the integrated circuit manufacturing process. Its core function is to efficiently and stably ionize the gas used for cleaning (NF3) or the gas process gas (NH3, O2), thereby greatly enhancing the activity of the reaction gas and the consistency of the process. Compared with traditional plasma sources, there is a physical separation between the plasma generation region and the processing region in the remote plasma source. After the plasma is generated, it is transmitted to the processing region, and the active particles (such as free radicals, ions, and neutral particles) diffuse during the transmission process. This design enables the plasma to act on the surface of the material to be processed more uniformly and efficiently.

[0003] The dissociation rate is one of the important parameters characterizing the reaction efficiency of the remote plasma source. It refers to the proportion of the reaction gas dissociated into active species (such as free radicals, mononuclear ions, polynuclear ions, and neutral atoms) in a strong electric field environment. A higher and more stable dissociation rate means that at the same input power, a higher plasma density can be obtained, thereby reducing the cleaning time of the process chamber, improving the processing efficiency and quality. Therefore, the measurement of the RPS dissociation rate and its stability is crucial.

[0004] However, as a potent greenhouse gas (GWP = 17200), NF3 should not be directly discharged, and the residual gas after RPS dissociation rate testing needs to be treated. For the undissociated NF 3， Traditional treatment methods such as high-temperature incineration have problems of high energy consumption (above 1200°C), and the catalytic method is prone to deactivation due to fluorine corrosion. Existing electric heating technologies have problems such as low decomposition efficiency (<95%) and secondary pollution of by-product corrosive gases (such as F2, HF). Summary of the Invention

[0005] The present application provides an electrothermal adsorption type tail gas treatment device for RPS dissociation rate testing, which solves the problem of inconvenient tail gas treatment after RPS dissociation rate testing in the prior art, thereby efficiently treating the residual gas after RPS dissociation rate testing.

[0006] The embodiment of the present application provides an electrothermal adsorption type tail gas treatment device for RPS dissociation rate testing, including: a heating system, a water vapor injection system, a cooling system, and an adsorption system that are connected in sequence; the heating system includes a segmented reaction tube, and its temperature field increases from the inlet end to the outlet end; the adsorption system includes a primary solid adsorption layer and a secondary circulating spray system.

[0007] The beneficial effects of the above embodiment are as follows: The electrothermal adsorption type tail gas treatment device realizes the step-by-step decomposition of NF3 through segmented heating, combines a multi-stage adsorption system to efficiently neutralize harmful gases (such as HF), can effectively remove harmful substances in the tail gas, and reduce environmental pollution.

[0008] Based on the above embodiment, the present application can be further improved as follows: In one embodiment of the present application, the segmented reaction tube of the heating system is a three-stage coaxial nested structure, including a preheating section, a main decomposition section, and a deep cracking section. Each section is independently temperature-controlled and heated by a high-frequency induction coil. By precisely adjusting the reaction temperature gradient (500°C → 1000°C) through three independent temperature controls, the decomposition efficiency of NF3 is improved (>99.5%), and at the same time, the high-frequency induction heating reduces the energy consumption by 30%.

[0009] In one embodiment of the present application, the water vapor injection system is an annular injection device, and the injection amount of ultrapure water vapor is controlled by a mass flow meter, which is dynamically matched with the molar ratio of NF3. Dynamically matching the molar ratio of water vapor to NF3 (0.8:1~1.2:1) ensures that F2 is fully converted into HF and reduces the risk of secondary pollution of by-products.

[0010] In one embodiment of the present application, a heat exchanger is provided between the outlet of the water vapor injection system and the inlet of the heating system, which is used to recover the waste heat of the tail gas to preheat the inlet gas. The inlet gas temperature is raised to 300°C through waste heat recovery, reducing the energy consumption of the heating system (total power consumption ≤ 1.5 kWh / m³ NF3) and improving the energy utilization rate.

[0011] In one embodiment of the present application, the secondary circulating spray system of the adsorption system is configured with a pH value feedback device, which is used to dynamically adjust the concentration and flow rate of the spray liquid. The pH value of the spray liquid is monitored in real time and the concentration of the Ca(OH)2 solution (10wt%) is adjusted to ensure the HF neutralization efficiency (tail gas HF concentration < 1 ppm), and at the same time prevent fouling of the adsorption tower.

[0012] In one embodiment of the present application, a particle collection tank is further provided at the outlet of the water vapor injection system, which is used to capture the solid particles generated by the reaction. Collect the solid particles generated in the reaction (such as CaF2 precipitate), avoid pipeline blockage, and extend the service life of the equipment.

[0013] In one embodiment of the present application, an emergency pressure relief valve is provided between the air inlet of the heating system and the inlet of the adsorption system, which is used to open for pressure relief when the pressure exceeds the limit. It can quickly relieve pressure in case of abnormal pressure, prevent the reaction tube or pipeline from bursting, and improve the operation safety of the equipment.

[0014] In one embodiment of the present application, it further includes a gas content detection system. The gas content detection system includes an NF3 detector and an HF sensor, which are used to monitor the concentrations of NF3 and HF in the tail gas in real time and feedback to the control system to adjust the heating power and the water vapor injection amount. By monitoring the concentrations of NF3 and HF in real time and dynamically adjusting the heating power and the water vapor flow rate, it ensures that the tail gas treatment meets the standards (NF3 decomposition rate > 99%, HF < 1 ppm), and adapts to high-concentration shock load conditions. Description of the Drawings

[0015] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0016] Figure 1 It is a front view structural schematic diagram of a dissociation rate test device for a remote plasma source in an embodiment of the present application; Figure 2 It is a three-dimensional structural schematic diagram of a dissociation rate test device for a remote plasma source in an embodiment of the present application; Figure 3 It is a schematic diagram of the relationship between the components in the process of obtaining the dissociation rate in an embodiment of the present application; Figure 4 It is a schematic diagram of the function of the RPS control test bench display screen in an embodiment of the present application; Figure 5 It is a flowchart of the method for obtaining the dissociation rate in an embodiment of the present application; Figure 6 It is a structural schematic diagram of the tail gas treatment equipment in an embodiment of the present application; Figure 7 It is a connection diagram of the control module of the tail gas treatment equipment in an embodiment of the present application; Figure 8 It is a working flowchart of the tail gas treatment device in an embodiment of the present application; Figure 9 It is a traditional structural schematic diagram of the water-cooled pipeline at the outlet, where 9(a) is the internal structural schematic diagram and 9(b) is the external structural schematic diagram; Figure 10This is a schematic structural diagram of the water-cooled pipe at the air outlet in the embodiment of the present application, where 10(a) is the internal structural diagram and 10(b) is the external structural diagram; Figure 11 This is a flowchart of the steps of a method for diagnosing faults in the water pipe at the air outlet of a remote plasma source in the embodiment of the present application; Figure 12 This is a flowchart for evaluating the importance degree relationship between scaling, blockage, micro-leakage and process parameters; Figure 13 This is a flowchart for constructing a decision tree for evaluating the importance degree relationship; Figure 14 This is a schematic diagram of the score ranking of the importance degrees of scaling, blockage, micro-leakage and process parameters.

[0017] Among them, 100 - remote plasma source; 101 - air inlet; 102 - equipment status display screen; 103 - water-cooled pipe; 1031 - cooling water channel; 104 - etching test bench; 105 - etching observation window; 106 - RPS inlet and outlet; 107 - gas pressure gauge; 108 - sampling gas pressure gauge; 200 - gas ionization detection device; 201 - Fourier transform infrared spectrometer; 202 - ionization gas sample collection pipeline; 203 - spectrometer tail gas output pipeline; 300 - RPS control test bench; 301 - test bench display screen; 302 - test bench status operation indicator light; 400 - host computer system; 500 - vacuum pump; 501 - tail gas transmission pipeline; 600 - tail gas treatment equipment; 601 - tail gas treatment equipment air inlet; 602 - tail gas treatment equipment air outlet. Specific embodiments

[0018] The present invention will be further clarified below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. After reading the present invention, various equivalent forms of modification of the present invention by those skilled in the art all fall within the scope defined by the appended claims of the present application.

[0019] It should be noted that: similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In the description of the present invention, it should also be noted that unless otherwise clearly defined and limited, the terms "set", "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

[0020] Example 1 of this application provides a dissociation rate testing device for a remote plasma source, which solves the problem of inconvenient testing of the dissociation rate of RPS in the prior art, thereby facilitating and accurately testing the dissociation rate of RPS.

[0021] Example 2 of this application provides an electrothermal adsorption type tail gas treatment device for RPS dissociation rate testing, which solves the problem of inconvenient tail gas treatment after testing the dissociation rate of RPS in the prior art, thereby efficiently treating the remaining gas after RPS dissociation rate testing.

[0022] Example 3 of this application provides a heat dissipation water pipe structure at the gas outlet of a remote plasma source, which solves the problems in the prior art that the uneven temperature of the heat dissipation water pipe at the gas outlet affects the accuracy of dissociation rate testing and the low heat dissipation efficiency of the heat dissipation water pipe, thereby improving the temperature uniformity and heat dissipation efficiency of the heat dissipation water pipe.

[0023] Example 4 of this application provides a method for diagnosing faults in the water pipe at the gas outlet of a remote plasma source, which solves the problem of lack of fault monitoring for the heat dissipation water pipe at the gas outlet in the prior art, thereby realizing accurate identification of fouling, blockage and leakage faults.

[0024] Example 1: As Figures 1-3 shown, a dissociation rate testing device for a remote plasma source includes a remote plasma source 100, a gas ionization detection device 200, a Fourier transform infrared spectrometer 201, an RPS control test bench 300, a host computer system 400, and a tail gas treatment device 600 ( Figure 2 omitted in the figure); The remote plasma source 100 is used to dissociate process gases and perform processes such as thin film deposition and cleaning under vacuum conditions; the remote plasma source 100 includes a dissociation chamber, an air inlet 101, an air outlet, and an RPS water inlet and outlet 106; the air outlet is connected to an etching test bench 104 through an air outlet water cooling pipe 103; the etching test bench 104 is provided with an etching observation window 105, and a gas pressure gauge 107 is arranged on the etching test bench 104; the water flow rate of the cooling water of the RPS water inlet and outlet 106 is controlled by the RPS control test bench 300; the etching test bench 104 is used to etch thin films on materials such as silicon wafers and wafers; the gas pressure gauge 107 is used to monitor the internal pressure of the etching test bench 104 and is regulated by the RPS test bench; the remote plasma source 100 is also provided with an equipment status display screen 102, and the equipment status display screen 102 is used to observe and set the operating status, such as information on power, voltage and current.

[0025] The gas ionization detection device 200 includes a gas dissociation circuit control device (maintenance gas input control module) for maintaining gas input, which is connected to the dissociation chamber of the remote plasma source 100 and is used to control the amount of maintenance gas input into the dissociation chamber; the gas ionization detection device 200 is also provided with a sampling gas pressure gauge 108 to ensure an ultra-low pressure test environment of 100 mTorr, guaranteeing the accuracy of the remaining gas amount collection; the gas ionization detection device 200 further includes an output detection unit, which is connected to the dissociation chamber through the ionized gas sample collection pipeline 202 and is used to detect the amount of remaining maintenance gas in the gas of the dissociation chamber; the gas ionization detection device 200 also includes an output calculation unit, which is connected to the maintenance gas input gas dissociation circuit control device and the output detection unit, and is used to calculate the ionization rate according to the amount of maintenance gas input into the dissociation chamber and the amount of remaining maintenance gas in the gas output from the dissociation chamber.

[0026] The gas ionization detection device 200 respectively detects the amount M of the remaining gas and the amount N of the input maintenance gas in the gas of the dissociation chamber, and the dissociation rate is 1 - M / N; during the remote plasma process, when nitrogen trifluoride NF3 is used as the process gas and is ionized by the plasma, it decomposes into nitrogen and fluorine atoms, and the fluorine atoms etch the silicon wafer to form a thin film; when the amount M of the remaining NF3 gas is less than the residual gas threshold, it indicates that the NF3 waste gas is sufficiently small, and since NF3 is toxic, the etching stage 104 can be opened at this time to take out the silicon wafer, and the heating furnace of the tail gas treatment device also stops working at this time to increase the power application efficiency; when the amount M of the remaining NF3 gas is greater than or equal to the residual gas threshold, it indicates that the ionization process of the process gas has not ended, and the silicon wafer is continuously etched, and the heating furnace of the tail gas treatment device also needs to work continuously.

[0027] The Fourier transform infrared spectrometer 201 is used to collect the infrared spectral data of the remaining maintenance gas. The spectrometer accesses the spectral data of the remaining maintenance gas in the etching stage 104 through the ionized gas sample collection pipeline 202; it is connected to the tail gas transmission pipeline through the spectrometer tail gas output pipeline 203 and is output to the tail gas treatment device by the vacuum pump 500.

[0028] The RPS control stage 300 is provided with a gas flow meter, a pressure gauge, a water flow meter, a stage display screen 301 and a stage status operation indicator light 302. The gas flow meter, the pressure gauge and the water flow meter are used to detect the intake gas flow rate, the chamber pressure and the cooling water flow rate of the remote plasma source 100. The RPS control stage 300 is used to control the process gas flow rate, the vacuum pressure, the water cooling system, etc. of the remote plasma source 100, including the display of parameters such as the operating state, power, voltage and current of the equipment, as well as the recording of fault information and the modification of process parameters. Among them, the gas flow meter controls the gas flow rate entering the RPS and cooperates with the vacuum pump 500 to achieve the output of different powers of the RPS, simulating the actual operating conditions.

[0029] Among them, the functional diagram on the display screen 301 of the RPS test bench is as Figure 4 shown. The test bench control module includes a process gas module, a vacuum pressure module, a water cooling module, a parameter display module, a fault information recording module, and a process parameter module; the process gas module can control and read the flow rate of the input gas in real time, cooperate with the vacuum pump 500 to achieve the output of different powers of the RPS, and simulate the actual operating conditions; the vacuum pressure module can control and read the pressure in the RPS cavity and the Fourier transform infrared spectrometer 201 by setting the pressure value; the water cooling module provides water cooling for the plasma source, can control the inlet and outlet water flow rates and read them in real time; the parameter display module can read the actual power value, bus bar current and voltage in the RPS, as well as the operating status of the equipment; first, the power switch is started, after introducing the process gas and setting the power value, it is determined whether the indicator lights of "Initialization Status (Ready)" and "Power Input (AC OK)" are always on. "Initialization Status (Ready)" represents that the equipment initialization status is normal; "Power Input (AC OK)" indicates that the power input is within the allowable range; then the ignition switch is pressed, and "Ignition Status (Plasma ON)" indicates that the equipment has been ignited successfully or the equipment is processing the process gas, otherwise it means that the equipment is working without ignition or the ignition has failed; "Equipment Alarm (Fault)" always on indicates that the equipment has an alarm, otherwise there is no alarm for the equipment; the fault information recording module can click to view the faults sent by the equipment, including the time when the fault occurred, the type of the fault, and the number of times the current fault type has occurred; among them, the fault types include: over-temperature alarm (OT), over-power alarm (OP), abnormal input voltage (ACV), output current drop (LC), output current exceeding the limit (OC), water leakage alarm (Water Leak); the process parameter module can select the ignition process or the burn-in aging process to test the RPS; This detection device is also designed with a real-time monitoring function, which can immediately feedback the dissociation state of the plasma. Through real-time monitoring, the working conditions of the plasma source can be adjusted in time to ensure the stability and consistency of the production process.

[0030] The host computer system 400 is used to perform operations such as preprocessing, feature extraction, and pattern recognition on the Fourier transform infrared spectrum data for the dissociation rate detection steps.

[0031] The exhaust gas treatment device 600 is a system for treating various process exhaust gases at the site, and is provided with an exhaust gas treatment device air inlet 601 and an exhaust gas treatment device air inlet 602. The exhaust gas treatment device air inlet 601 is communicated with the outlet of the vacuum pump 500 through a pipeline. The inlet of the vacuum pump 500 is communicated with the dissociation chamber through the exhaust gas transmission pipeline 501. The vacuum pump 500 ensures a low-pressure environment in the reaction chamber. At low pressure, the collisions between gas molecules are reduced, enabling more effective excitation of gas molecules during the plasma treatment process; it also promotes the stable generation and maintenance of the plasma. The exhaust gas pollutants are introduced into the exhaust gas treatment device 600.

[0032] Among them, as Figure 5 shown, in this embodiment, the dissociation rate detection method adopts the traditional method, such as S1. The Fourier transform infrared spectrometer 201 collects the near-infrared spectra of different dissociation rates of the remote plasma source 100; the gas ionization detection device 200 respectively detects the amount M of the remaining gas and the amount N of the input maintenance gas in the gas of the dissociation chamber, and the dissociation rate is 1 - M / N; S2. Apply the near-infrared spectral data of different dissociation rates to establish an ionization rate data set of the remote plasma source 100; S3. Adopt the same near-infrared spectrum acquisition conditions, sample the near-infrared spectrum of the plasma source to be detected, compare the measured characteristic spectral peak with the ionization data set, judge the current concentration of the remaining gas (NF3), and the dissociation rate is 1 - the concentration of the remaining gas (NF3).

[0033] This device adopts the infrared mass spectrometry analysis and detection technology, which can realize the high-precision and high-sensitivity measurement of various active particles in the plasma, thereby accurately calculating the dissociation rate and providing reliable data for the performance evaluation of the plasma source. And by applying the near-infrared spectral data of different dissociation rates at different pressures, flow rates and temperatures, establishing an ionization rate data set, identifying the characteristic spectral peak according to the detected amount of the remaining NF3 gas, and comparing it with the ionization rate data set, the gas dissociation rate at different pressures, flow rates and temperatures can be detected in real time.

[0034] This test device integrates an automated control system, integrates infrared mass spectrometry analysis and the RPS exhaust gas treatment system, coordinates the work of each functional module through the automated control system, can automatically complete the detection of the relevant technical indicators of the RPS, realizes the reliable test of the RPS dissociation rate, and at the same time simulates the actual operating conditions of the RPS, without the need to detect the RPS on the actual integrated circuit production terminal equipment, with low cost and short cycle. This test device realizes the full-process monitoring and closed-loop control of the operating state of the plasma source, improving the detection accuracy of the dissociation rate and the process stability.

[0035] Embodiment 2: As Figures 6-7As shown in the figure, an electrothermal adsorption type tail gas treatment device for a remote plasma source dissociation rate test device includes a control system, a gas content detection system, and a heating system, a water vapor injection system, a cooling system, and an adsorption system (neutralization tower) that are connected in sequence. A particle collection tank is also provided at the outlet of the water vapor injection system to collect solid particles (such as CaF2 precipitate) generated during the reaction, avoid pipeline blockage, and extend the service life of the equipment. A heat exchanger is provided between the outlet of the water vapor injection system and the inlet of the heating system to recover the waste heat of the tail gas to preheat the inlet gas, raise the inlet temperature to 300 °C through waste heat recovery, and reduce the energy consumption of the heating system. The inlet of the heating system is connected to the vacuum pump of the remote plasma source dissociation rate test device.

[0036] Among them, the heating system uses a three-stage coaxial nested nickel-based alloy reaction tube (Inconel 600), and the length ratio of each section is 1:2:1 (corresponding to the preheating section, the main decomposition section, and the deep cracking section), and the temperature gradient is 500 °C (preheating section) → 800 °C (main decomposition section) → 1000 °C (deep cracking section). The inner wall is sprayed with a 200 μm thick Al2O3 ceramic layer (purity ≥ 99.5%) to withstand fluorine gas corrosion. High-frequency induction coils (copper tube diameter 8 mm, turn spacing 5 mm) are wound around the outer wall of each section, and the output power (0~20 kW) is controlled by an independent variable frequency power supply (frequency 50-100 kHz) to achieve precise adjustment of the temperature gradient.

[0037] Adopt high-frequency induction heating technology: utilize the electromagnetic eddy current effect to directly heat the reaction tube wall, with a heating rate of up to 50 °C / s, saving 30% energy compared with traditional resistance heating.

[0038] The water vapor injection system is a water vapor injection ring (made of 316L stainless steel, aperture 0.5 mm) installed at the outlet of the deep cracking section. The injection amount of ultra-pure water vapor is controlled by a mass flow meter (MFC), and it is dynamically matched with the NF3 molar ratio (range 0.8:1~1.2:1). Dynamically matching the molar ratio of water vapor and NF3 (0.8:1~1.2:1) ensures that F2 is fully converted into HF and reduces the risk of secondary pollution of by-products. The decomposition of NF3 requires high-temperature cracking or catalytic hydrolysis reactions, and its chemical equation is usually: 2NF3 + 3H2O → 6HF + NO + NO2; water vapor serves as a hydrolysis medium in this reaction, providing hydroxyl -OH to accelerate the breaking of the N-F bond. If the water vapor is insufficient, that is, the molar ratio is lower than 0.8:1, NF3 may not be completely decomposed, and the remaining NF3 will be discharged in the form of toxic gases; if the water vapor is excessive, higher than 1.2:1, it may dilute the reaction system, reduce the reaction efficiency, and even inhibit the decomposition reaction due to a local temperature drop.

[0039] The cooling system is used to cool the mixed gas, and the cooling is determined by the pipeline length and the water flow rate, generally cooling to 500 ± 50 °C.

[0040] The adsorption system is a neutralization absorption tower, which adopts a two-stage series design. The first-stage tower is filled with Ca(OH)2 particles (particle size 3 - 5 mm) for preliminary adsorption of HF; the second-stage tower is equipped with a circulating spray system with pH value feedback (Ca(OH)2 solution concentration 10 wt%), and the spray rate is 5 L / min. By circulating and spraying the Ca(OH)2 solution, HF is fixed as CaF2 precipitate, achieving a fluorine content in the tail gas < 1 ppm.

[0041] The gas content detection system includes several NF3 detectors + electrochemical HF sensors, and the control system controls the above-mentioned systems according to the set program. By real-time monitoring the concentrations of NF3 and HF, the heating power and steam flow rate are dynamically adjusted to ensure that the tail gas treatment meets the standards (NF3 decomposition rate > 99%, HF < 1 ppm), and it can adapt to high-concentration shock load conditions.

[0042] The tail gas treatment equipment in this Example 1 adopts the above-mentioned electrothermal adsorption type tail gas treatment equipment, which includes the processes of thermal oxidation decomposition and reagent adsorption. The waste gas generated by the process is decomposed at high temperature through the heating system, and then discharged to the plant utility treatment system through dry adsorption treatment. A high-temperature system (400 - 1200 °C) generated by the heating furnace is used. It decomposes and oxidizes the NF3 gas that was not dissociated by the previous-stage equipment at high temperature, and processes the toxic gas into a non-toxic reactant. After cooling through the cooling system, an activated chemical adsorption system is used for activated chemical adsorption or reaction to generate a deposited substance, achieving complete absorption of the toxic and corrosive gas. The harmless gas after treatment will enter the plant exhaust system.

[0043] As Figure 8 shown, this Example also provides a working flow chart of an electrothermal adsorption type tail gas treatment device, and the main process is as follows: S1. Heating system: A nickel-based alloy reaction tube with three-stage independent temperature control is adopted (lined with ALO, and the ceramic coating prevents the oxidation of fluorine atoms F and reduces the service life). The temperature gradient is 500 °C (preheating section) → 800 °C (main decomposition section) → 1000 °C (deep cracking section), ensuring that NF is gradually decomposed into NF3 and F2, and improving the NF3 decomposition efficiency.

[0044] Among them, each of the three-stage independent temperature controls is equipped with an NF3 detector. The NF3 concentration of the input gas is detected as n vol% in the preheating stage, and the flow rate is lm 3 / h. If the concentration n is less than the first concentration threshold N1 and the flow rate l is less than the flow rate threshold L, the heating furnace temperature in the preheating section is set to 500 °C (heating rate 30 °C / s, power 8 kW). (2) Main decomposition section: 800 °C (constant temperature accuracy ±5 °C, power 15 kW). When the NF3 concentration is less than the second concentration threshold N2, it enters the deep cracking stage; otherwise, continue heating. (3) Deep cracking section: 1000 °C (power 18 kW, residence time ≥2 s). When the NF3 concentration is less than the third concentration threshold N3, it enters the steam injection system; When the NF3 concentration n vol% of the input gas is detected in the preheating stage and the flow rate l m 3 / h. If the concentration n is greater than or equal to the first concentration threshold N1, that is, when the heating system detects a concentration increase within 0.5 s, the system automatically adjusts, raises the temperature of the main decomposition section to 850 °C, and increases the power to 20 kW. And when the NF3 gas flow rate l is greater than or equal to the flow rate threshold L, the inlet gas flow rate is reduced by 15% through the inlet gas valve, and the residence time in the preheating stage is extended. When the NF3 concentration is less than the second concentration threshold N2, it enters the deep cracking stage; otherwise, continue heating. Deep cracking section: 1000 °C (power 18 kW, residence time ≥2 s). When the NF3 concentration is less than the third concentration threshold N3, it enters the steam injection system; and the steam flow rate is synchronously increased to km 3 / h (molar ratio 1.05:1).

[0045] S2. In-situ neutralization system: When the NF3 concentration n vol% of the input gas is detected in the preheating stage and the flow rate l km 3 / h. If the concentration n is greater than or equal to the first concentration threshold N1 or when the NF3 gas flow rate 1 is greater than or equal to the flow rate threshold L, the steam injection system needs to synchronously increase the steam flow rate by k m 3 / h.

[0046] Steam injection system: Ultra-pure steam is injected at the end of the reactor (flow rate to NF3 molar ratio 1:1) to convert F2 into HF gas. Reaction formula: 2F2 + 2H2O → 4HF + O2.

[0047] Multi-stage alkaline adsorption system: The neutralization absorption tower adopts a two-stage series design. The first-stage tower is filled with Ca(OH)2 particles (particle size 3 - 5 mm) for preliminary adsorption of HF. The second-stage tower is equipped with a circulating spray system with pH feedback (Ca(OH)2 solution concentration 10 wt%), and the spray rate is 5 L / min. The pH value of the spray liquid is monitored in real time and the concentration of the Ca(OH)2 solution (10 wt%) is adjusted to ensure the HF neutralization efficiency (tail gas HF concentration < 1 ppm), while preventing fouling of the adsorption tower. The Ca(OH)2 solution is circulated and sprayed to fix HF as CaF2 precipitate, achieving a tail gas fluorine content < 1 ppm. When the NF3 concentration monitored by the NF3 detector in the adsorption system is less than the fourth concentration threshold N4, it is discharged into the plant utility system; otherwise, it is re-introduced into the multi-stage alkaline adsorption system by an air pump. Since when NO and NO# are mixed in a 1:1 ratio, they can be absorbed by the calcium hydroxide solution to form calcium nitrite and water, and nitrogen dioxide can directly react with calcium hydroxide to form calcium nitrate and calcium nitrite, the nitrogen oxides in the tail gas can be treated together by the Ca(OH)2 solution.

[0048] S3. Waste heat recovery and intelligent control: The heat exchanger conducts countercurrent heat exchange between the 1000°C tail gas and the inlet gas, raising the NF3 inlet gas temperature from 25°C to 300 ± 10°C. The waste heat of the 1000°C tail gas is recovered through the heat exchanger to preheat the inlet to 300°C, which can reduce energy consumption.

[0049] Dynamic regulation is carried out using gas sensors (NF3 detector + electrochemical HF sensor): The NF3 concentration is monitored in real time through the gas sensors, and the heating power and the inlet gas flow rate are adaptively adjusted to ensure the stability of the decomposition rate.

[0050] Example 1 of the working scenario of the above electro-adsorption type tail gas treatment equipment: Standard working condition treatment: A. Operating parameters: Input gas: NF3 concentration 10 vol%, flow rate 12 m 3 / h, with O2 as the carrier gas (accounting for 90%).

[0051] Temperature control: (1) Preheating section: 500°C (heating rate 30°C / s, power 8 kW). (2) Main decomposition section: 800°C (constant temperature accuracy ±5°C, power 15 kW). (3) Deep cracking section: 1000°C (power 18 kW, residence time ≥ 2 s).

[0052] B. Neutralization system: Steam flow rate 6 m 3 / h, Ca(OH)2 solution spray volume 8 L / min.

[0053] C. Performance Results: (1) Decomposition Efficiency: The NF3 decomposition rate is 99.7% (residual NF3 concentration < 50 ppm analyzed by FTIR spectroscopy). (2) By-product Control: The F2 conversion rate > 99.9%, and the HF concentration in the tail gas < 0.5 ppm (meeting the GB16297-1996 standard). (3) The purity of CaF2 precipitate at the outlet of the secondary absorption tower ≥ 98%, which can be directly recycled as industrial raw materials. (4) Energy Consumption Index: The comprehensive power consumption is 1.2 kWh / m 3 NF3, saving 52% energy compared with the traditional incineration method.

[0054] Example 2 of the working scenario of the above electroadsorption tail gas treatment equipment: Treatment of high-concentration NF3 shock load: A. Operating Parameters: Input Gas: NF3 concentration 30 vol%, flow rate suddenly increased to 20 m 3 / h (simulating abnormal process conditions).

[0055] B. Dynamic Response: The heating system detected the increase in concentration within 0.5 s and automatically adjusted: the main decomposition section was heated to 850 °C, and the power was increased to 20 kW. The steam flow rate was synchronously increased to 10 m 3 / h (molar ratio 1.05:1). The inlet gas flow rate was reduced by 15%, and the residence time was extended to 3 s.

[0056] C. Performance Results: (1) Decomposition Efficiency: The NF3 decomposition rate is 99.6%, and there is no F2 leakage (sensor alarm threshold 0.1 ppm). (2) System Stability: The temperature fluctuation < ±10 °C, and the pH value of the neutralization tower is maintained at 8.5 - 9.0 (to avoid scaling of Ca(OH)2).

[0057] The key process verification data of the above working scenarios Examples 1 and 2 are shown in Table 1 below:

[0058] Handling of Special Situations: This electrothermal adsorption tail gas treatment equipment also includes an emergency pressure relief valve installed between the inlet of the heating system and the inlet of the adsorption system. When the inlet pressure increases, the emergency pressure relief valve will open, and the tail gas will go to the adsorption tank through the bypass pipeline to prevent back pressure at the rear end.

[0059] This tail gas treatment device realizes the step-by-step decomposition of NF3 through segmented heating, combines a multi-stage adsorption system to efficiently neutralize harmful gases (such as HF), can effectively remove harmful substances in the tail gas, and reduce environmental pollution. The principle is as follows: Preheating Section: Gradually heat the waste gas to the initial reaction temperature to avoid uneven reactions or incomplete decomposition in local areas due to sudden high temperature of the gas. Preheating can also reduce the damage of thermal stress to the equipment.

[0060] Main decomposition stage: The temperature rises to the optimal decomposition temperature of 800°C, at which the chemical bonds of NF3, i.e., NF bonds, are more easily broken, generating N2 and F2 through thermal decomposition or catalytic reaction, or further converting into stable products such as HF. This stage ensures that most NF3 is decomposed quickly.

[0061] Deep cracking stage: Maintain or slightly exceed the temperature of the main reaction zone at 1000°C, extend the residence time to completely decompose the residual NF3, prevent the by-products from recombination, and inhibit the reverse reaction of F2.

[0062] NF3 decomposition is an endothermic reaction, and high temperature is conducive to the thermodynamic equilibrium moving toward the product direction. However, maintaining high temperature throughout the process will significantly increase energy consumption. And a single high temperature may lead to side reactions, such as the generation of NO x or other fluorides. Controlling the temperature in stages can optimize the reaction path, ensuring that NF3 is preferentially decomposed into target products, such as N2, F2 / HF, and reducing harmful byproducts. Through three-stage temperature gradient control, the heating furnace achieves fine regulation of the NF3 decomposition process, taking into account the reaction rate, thoroughness and energy efficiency, and ultimately increases the NF3 decomposition rate to more than 99.5%, effectively reducing the emission of this potent greenhouse gas.

[0063] Embodiment 3: Figure 9 The conventional structure diagram of the air outlet water cooling pipe is shown. Figure 9 Where L is the length of the water pipe, l is the inner diameter of the cooling water channel, d is the inner diameter of the water pipe, and D is the outer diameter of the water pipe; an increase in the length of the heat dissipation water pipe may mean a longer cooling time, resulting in a lower temperature in the plasma area. If the temperature is too low, it may be detrimental to the dissociation reaction, and the dissociation rate may drop by 20%-30%, because the gas dissociation process requires high temperature with sufficient energy. On the contrary, if the water pipe is too short, the cooling is insufficient, or the temperature is too high, it may cause equipment damage or reaction runaway, interfering with the stability of the dissociation reaction.

[0064] A water pipe with a larger diameter can allow for a larger water flow rate, improve cooling efficiency, and remove heat faster to reduce temperature. However, a too large diameter may reduce flow rate, affect turbulence, and thus reduce heat transfer efficiency. On the contrary, a smaller diameter may increase flow rate, but may cause excessive pressure drop, increase water pump load, and even cause poor cooling effect due to insufficient flow.

[0065] In the remote plasma test system, the design of the outlet water cooling pipe directly affects the stability of the plasma temperature and free radical distribution, and thus affects the measurement accuracy of the dissociation rate. A pipe that is too short will lead to insufficient heat dissipation, resulting in an increase in the outlet temperature, accelerated free radical recombination, and a low dissociation rate measurement value; a pipe that is too long will increase the flow resistance pressure drop ΔP, requiring higher pump power, and may cause local boiling due to excessive coolant temperature rise, destroying temperature uniformity.

[0066] Figure 10 The optimized structure diagram of the water-cooled pipe 103 at the outlet of the dissociation rate test device of a remote plasma source provided in this embodiment is shown; the structure of the water-cooled pipe at the outlet is improved and divided into multiple segments with gradually decreasing diameters. Each segment has its own pipe length L, pipe diameter D, and inner diameter l of the cooling water channel 1031. Specifically: S1: Determine the heat dissipation requirement of the water-cooled pipe through thermodynamic calculations to avoid interference from local temperature fluctuations on the plasma dissociation state.

[0067] According to the power of the plasma source, gas flow rate, and gas type (such as NF3 / Ar mixture), calculate the heat load at the plasma outlet Q . Heat load formula: Q = P · η , where P is the input power, η is the energy conversion efficiency. The temperature change can be further calculated from the gas parameters: ; where m is the mass flow rate of the gas flow, C m is the specific heat capacity at constant pressure of the mixed gas, which is determined by the gas type and mixing ratio. Select deionized water or ethylene glycol solution as the coolant, and set the flow rate V (L / min) and the temperature rise of the cooling water T in . Usually, control the temperature rise of the outlet water and inlet water between 10~20°C to avoid vaporization or affecting the heat dissipation efficiency; ensure that the coolant temperature rise Δ T is controlled within a reasonable range, where Δ T ≤5°C.

[0068] The flow rate can be expressed as , where ρ is the density of the coolant, where C p is the specific heat capacity of water (about 4186 J / (kg·°C)).

[0069] S2: By controlling the pipe length, balance the heat dissipation efficiency and flow resistance to avoid interference from temperature gradients on the dissociation rate measurement.

[0070] Pipe length L , k is the thermal conductivity of the pipe material, K is the proportionality coefficient, K is an empirical constant, usually taking a value of 0.8 - 1.2. Then the length of the outlet cooling pipe can be expressed as: (1); Among them, the length L of the air outlet cooling pipe can be represented by the lengths L1, L2, and L of the first, second, and nth sections of the water pipe, that is: n That is: (2); S3: Within the allowable ΔP range, optimize the design by adjusting the length L or the diameter D. If the pressure loss is too high, it is necessary to increase the pipe diameter or shorten the length; Control the target water flow velocity v between 1 and 3 m / s to avoid excessive turbulence resulting in high pressure loss or poor heat dissipation of the water pipe caused by laminar flow. From the flow rate formula , the pipe diameter is initially derived as: (3); Among them, D1, D2, and D n represent the diameters of the first, second, and nth sections of the water pipe; Q1, Q2, and Q n represent the heat loads of the plasma air outlets in the first, second, and nth sections of the water pipe; The relationship between the water pipe length L and the pressure drop ΔP can be used to optimize the calculation of the length of each section of the water pipe. According to the Darcy - Weisbach formula, we have: (4); Among them, f is the friction coefficient, f is related to the Reynolds number Re and the pipe wall roughness. When water is at 20°C, the relationship is .

[0071] If there is a relationship of Re < 2000 in laminar flow, then f = 64 / Re; the inner diameter of the ith section of the water channel can be expressed as: (5); When P is greater than the first pressure drop threshold P1 of the set flow resistance, that is, the pressure loss ΔP is too high at this time, it is necessary to increase the pipe diameter or shorten the length to optimize the current ith section of the water pipe; from equation (4), the following equation can be derived: (6); Then, the pipe diameter and length after the optimized design are expressed as equations (7) and (8): (7); (8); Based on the thermodynamics and fluid mechanics formulas, accurately match the parameters of each section of the pipeline to ensure that the coolant temperature rise ΔT ≤ 5°C, maintain the stability of the plasma dissociation temperature, and reduce the measurement error of the dissociation rate.

[0072] The temperature of the remote plasma outlet is at its maximum value, and the temperature away from the outlet decreases successively. After design, when the water pipe approaches the outlet, the water pipe diameter D is increased and the inner diameter l of the water channel is decreased to increase the water channel density, so as to solve the problem of excessive temperature at the outlet; compared with Figure 9 the traditional water pipe design scheme in [reference], this embodiment adopts the method of water-cooled temperature gradient regulation, and designs appropriate lengths L, diameters D and inner diameters l of the water channels according to different water pipe segments, improving the heat dissipation efficiency of remote plasma water cooling.

[0073] The heat dissipation water pipe structure of the outlet balances the heat dissipation efficiency and flow resistance through variable diameter design, ensures the matching of heat dissipation requirements and flow pressure drop, avoids local boiling or insufficient cooling, and maintains the temperature stability of the plasma dissociation reaction. The heat dissipation water pipe structure of the outlet solves the problem of free radical recombination caused by excessive local temperature at the outlet, improves the measurement accuracy of the dissociation rate, and improves the heat dissipation efficiency.

[0074] For the heat dissipation efficiency verification requirements of the remote plasma source cooling system design, it is necessary to quantify the influence of different water channel parameters on temperature gradient control through multiple groups of control experiments; Example 1 is a three-section cooling water pipe design, and the variable parameters are set as follows: the inner diameter of the cooling water pipe is 4.2 cm, and the total length of the cooling water pipe L is 20.0 cm; the diameter of the outlet section D 1 is 12.3 cm, the length L 1 = 8.2 cm, and the inner diameter of the first section of the water channel l 1 is 1.5 cm; the diameter of the middle section D 2 is 8.3 cm, the length L 2 = 6.7 cm, and the inner diameter of the second section of the water channel l 2 is 2.0 cm; the diameter of the last section D 3 is 6.0 cm, the length L 3 = 5.1 cm, and the inner diameter of the third section of the water channel l 3 is 2.5 cm; Example 2 is a five-section cooling water pipe design, and the variable parameters are set as follows: the inner diameter of the cooling water pipe is 4.2 cm, and the total length of the cooling water pipe L is 20 cm; the diameter of the outlet section D 1 is 15.2 cm, the length L 1 = 6.0 cm, and the inner diameter of the first section of the water channel l 1 is 1.0 cm; the diameter of the second section of the water pipe D 2 is 12.1 cm, the length L 2 = 5.0 cm, and the inner diameter of the second section of the water channel l 2 is 1.2 cm; the diameter of the middle section D 3 is 10.0 cm, the length L 3 = 4.0 cm, and the inner diameter of the third section of the water channell The diameter of the 3rd water pipe is 1.5 cm; the diameter of the 4th water pipe D is 8.1 cm, and the length L of the 4th water pipe is 3.0 cm, and the inner diameter of the 4th water channel l is 1.7 cm; the diameter of the last section D of the 5th water pipe is 6.0 cm, and the length L of the 5th water pipe is 2.0 cm, and the inner diameter of the 5th water channel l is 2.0 cm; The control group is a traditional cooling water pipe, and its variable parameters are: the inner diameter of the cooling water pipe d is 4.2 cm, and the outer diameter D is 6.1 cm, and the total length of the cooling water pipe L is 20.0 cm, and the inner diameter l of the cooling water channel is 2.5 cm; The remote plasma source is preheated to a steady state at full power, and after maintaining for 10 minutes, it is ignited and turned off. Then, the cooling water circulation is started, and the water flow rate is maintained at 5 L / min. After 30 s, an infrared thermal imager is used to record the temperature at the gas outlet of the remote plasma source, the middle section temperature, and the temperature at the outlet of the cooling water end respectively. The experiment is repeated 3 times and the average value is taken, as shown in Table 2 below.

[0075]

[0076] Comparing Example 2 with Example 1, the 5-section gradient water channel is better than the 3-section gradient water pipe in terms of temperature control at the gas outlet, the middle section, and the end through refined segmented design; adding 2 more sections of high-density water channels at the gas outlet reduces the local thermal resistance and has a significant temperature drop effect; the refined segmentation of the 5-section water pipe gradient cooling structure makes the temperature gradient in the middle section smoother. At the end of the water channel, the 5-section water pipe gradient cooling structure can reduce the accumulation of residual heat through a longer cooling section and has a higher cooling efficiency; Comparing the water pipe gradient cooling structure with the traditional water pipe structure, the temperature of the highest temperature zone at the gas outlet is reduced from 525 °C to 384 °C, meeting the requirements of semiconductor processes for heat load control; by adjusting the water channel parameters in a gradient manner D 、 L 、 l , the temperature drop rate from the gas outlet to the end is increased by 40%, verifying the effectiveness of the temperature gradient design.

[0077] Example 4: In a remote plasma system, the scaling, blockage, or micro-leakage of the water pipe at the gas outlet will directly affect the heat dissipation efficiency, the stability of gas dissociation, and even cause safety accidents. A method for diagnosing faults in the water pipe at the gas outlet of a remote plasma source in this example combines multi-physical field sensing technology, data analysis, and intelligent algorithms to achieve real-time perception and early warning. As Figure 11 shown, it includes the following steps: S1: Monitor the flow resistance pressure drop ΔP in real time through the differential pressure sensors installed at the inlet and outlet of the outlet water pipe, collect the local temperature distribution data ΔT through the infrared thermal imager outside the wall of the outlet water pipe, and arrange a capacitive humidity sensor near the outlet water pipe to monitor the environmental humidity change ΔR; S2: Based on the Kalman filtering algorithm, fuse the data of ΔP, ΔT, and ΔR to eliminate noise interference, and obtain the state estimation values of the pressure drop, temperature, and humidity, ΔP(k), T(k), and R(k); S3: Construct the fouling / clogging objective function M and the leakage objective function N; Use the prediction mean of all decision trees as the final output to respectively fit the fouling, clogging, and micro-leakage formed by each combination of process parameters, and evaluate the importance degree relationship between fouling, clogging, and micro-leakage and each process parameter; S4: Assign the importance degree of each process parameter to the weight ratios of the differential pressure, flow rate, temperature, and humidity in the fouling, clogging, and micro-leakage objective functions M and N respectively; when M exceeds the first threshold M1, it is determined as fouling, and when it exceeds the second threshold M2, it is determined as clogging; when N exceeds the leakage threshold N1, it is determined as micro-leakage. M1 / M2 / N1 are all set values and are adjusted according to the actual situation.

[0078] The following are the key steps and technical solutions for the function design: The detection of water pipe fouling and clogging is as follows: The formation of water scale is due to the attachment of minerals in hard water on the inner wall of the water pipe under the action of high temperature and long time. Clogging is caused by the continuous accumulation of water scale gradually reducing the flow area of the water pipe; Install high-precision differential pressure sensors at the inlet and outlet of the water pipe, with an accuracy of ±0.1% FS. Fouling or clogging will cause an increase in local flow resistance and a significant rise in the differential pressure Δ P Set the initial differential pressure to P 0 kPa. If Δ P continuously rises to the first differential pressure threshold P 1 kPa, an alarm for excessive flow resistance pressure drop will be triggered. Measure the flow rate non-invasively and calculate the water flow through the time difference of acoustic wave propagation v , and if the water flow rate drops abnormally to the flow rate threshold v 1, such as from 10 L / min to 7 L / min, an alarm for abnormal flow rate will be prompted. Install an infrared thermal imager outside the pipe wall. The fouling area will form local high-temperature points due to poor thermal conductivity. When the temperature difference Δ T > 10°C, it can be identified. When the number of local high-temperature points is greater than the temperature threshold T 1, an over-temperature alarm will be triggered. The detection of water pipe micro-leakage is as follows: A capacitive humidity sensor is arranged near the air outlet to detect an abnormal increase in ambient humidity. The initial humidity is R 0RH. If the humidity suddenly rises to the humidity threshold R 1RH, a water pipe humidity anomaly alarm is triggered. In addition, the flow differential pressure and the attenuation rate of the water flow velocity in the water pipe also reflect to a certain extent whether there is a micro-leakage in the water pipe. After the water pump is turned off, a differential pressure sensor is used to monitor the pressure attenuation rate in the water pipe. If it is normal, <0.1 bar / min, and when there is a leakage, >0.5 bar / min. Similarly, the water flow velocity will also be appropriately attenuated during micro-leakage, and a non-invasive method can be used to measure the flow velocity.

[0079] To achieve real-time perception and early warning, in this embodiment, a Kalman filter algorithm is used to fuse multi-source data such as differential pressure, flow rate, temperature, and humidity to eliminate noise interference, and the state of the water pipe is inferred through the observed data.

[0080] The Kalman filter consists of two parts: prediction and update. By updating the Kalman gain, the weights of the prediction part and the observation part are adjusted to make the result closer to the true value. The steps are as follows: S1: System state equation: Establish the state equation of the system, that is, describe how the current state of the system is determined by the previous state and external inputs. Usually, this can be expressed in the form of a linear dynamic system: x ( k ) = Ax ( k- 1) + Bu ( k ) + w ( k ), where x ( k ) represents the state of the system at time k ; A is n * n the state transition matrix, B is the input control matrix, u ( k ) is the input at time k , w ( k ) is the system process noise. x ( k ) is the data value at the current moment, x ( k- 1) is the data value at the previous moment. The data values include multi-source data such as differential pressure, flow rate, temperature, and humidity.

[0081] S2: Observation equation: Establish the observation equation to describe how to obtain the observed value by measuring the system. Usually, it is also a linear relationship:y ( k ) = Hx ( k ) + v ( k ), where y ( k ) represents the observed value at time k , H is the observation matrix, v ( k ) is the observation noise.

[0082] S3: Prediction step: In the Kalman filter, the prediction step is first carried out, and the system state equation and prior information are used to estimate the current state and state uncertainty of the system. The uncertainty equations are as follows: (9); (10); In the formula, P - ( k ) is the prior estimate of the covariance matrix at time k ; P - ( k - 1) is the prior estimate of the covariance matrix at time k - 1; Q is the covariance matrix of the prediction error.

[0083] S4: Update step: Then the update step is carried out. The state predicted in the previous step is compared with the actual observed value, and the prediction value is corrected through the Kalman gain to obtain an estimate closer to the true state.

[0084] The three update equations are as follows: (11); In the formula, R is the covariance matrix of the observed value error; K ( k ) is the Kalman gain at time k ; (12); (13); In the formula P ( k ) is the covariance matrix at time k ; I is the identity matrix.

[0085] S5: Continuously iterate: Finally, continuously repeat the prediction and update steps to gradually optimize the estimation of the system state over time, and finally obtain state estimation values of differential pressure, flow rate, temperature, and humidity with high accuracy Δ P ( k )、 v ( k )、 T ( k )、 R ( k )。

[0086] S6: Fault type judgment: First, determine whether the system triggers alarms such as excessive flow resistance pressure drop, abnormal flow rate, over-temperature, or abnormal humidity. When an alarm command appears, the system needs to stop for inspection and perform fault type judgment; Respectively establish objective functions for scaling, blockage M and leakage faults N : The relationship between the importance of scaling and blockage fault characteristics and various process parameters is as follows: 1) Differential pressure (λ1): Scaling or blockage will cause mineral accumulation on the inner wall of the pipeline, increasing the flow resistance, thus increasing the differential pressure of the system. Since the differential pressure reflects the resistance of gas flow in the system, the increased flow resistance caused by scaling will directly increase the differential pressure; 2) Flow rate (λ2): Scaling or blockage affects the flow path, reducing the effective flow area of the pipeline, thus resulting in a decrease in gas flow rate; 3) Temperature (λ3): The reduced flow rate caused by scaling or blockage will lead to poor heat dissipation and cause local temperature rise; 4) Humidity (λ4): The humidity sensor is installed at the outlet of the RPS and does not reflect the effects of scaling and blockage; then: (14); The relationship between the importance of micro-leakage fault characteristics and various process parameters is as follows: 1) Differential pressure (λ1): When a micro-leakage occurs in the water pipe, the leakage will cause an increase in the pressure difference before and after the leakage point; 2) Flow rate (λ2): Micro-leakage will cause a decrease in the flow rate inside the water pipe, resulting in a reduction in the downstream flow rate; 3) Humidity (λ4): The humidity sensor is installed at the outlet of the RPS and can accurately sense the degree of water pipe leakage; then: (15); In Equation (14 / 15), t ( k ) is the current moment, t ( k-1) is the previous moment, Δ P ( k )、 v ( k )、 T ( k )、 R ( k ) are the state estimation values of differential pressure, flow rate, temperature, and humidity at the current moment, Δ P ( k- 1)、 v ( k -1)、 T ( k -1)、 R ( k -1) are the state estimation values of differential pressure, flow rate, temperature, and humidity at the previous moment, λ 1、 λ 2、 λ 3 are the weight ratios of differential pressure, flow rate, and temperature respectively; λ4 is the weight ratio of humidity, where λ4 > λ1, λ2. The weight coefficients λ1~λ4 are obtained by training based on historical fault data and are dynamically adjusted according to the service life of the pipeline.

[0087] When M is greater than the first fault threshold M 1, it is judged that there is scale deposition in the water pipe at this time; when M is greater than the second fault threshold M 2, where M 2 > M 1, then it is judged that there is a local blockage in the water pipe at this time; When N is greater than the leakage fault threshold N 1, it is judged that there is a micro-leakage phenomenon in the water pipe at this time.

[0088] This fault diagnosis method for the gas outlet pipeline realizes accurate identification of scale, blockage, and leakage (accuracy rate ≥ 95%) through multi-sensor collaborative monitoring (differential pressure, temperature, humidity) and Kalman filter data fusion, and reduces the false alarm rate to less than 5%.

[0089] Regarding the weight ratios of differential pressure, flow rate, temperature, and humidity λ 1-4 The evaluation of the importance relationship is further described as follows: As Figures 12-13 shown, the random forest regression algorithm evaluates the importance relationship between scale, blockage, micro-leakage and process parameters: The steps are as follows: Step P1: Bootstrap sampling: Using a linear regression model, the approximate linear relationships between scaling, blockage, and micro-leakage and each process parameter can be fitted. T sub-sample sets {D1, D2,..., D T} are drawn with replacement from the original data set D, and the sample size of each subset is N. The probability P(N) that each sample is selected in a single sampling is: (16); Then, the out-of-bag data set OOB composed of the unselected samples is used for error estimation and feature importance analysis.

[0090] Step P2: Decision tree construction: Randomly select features. Let the total number of features be M t , for each subset D t , construct a regression decision tree h t (x). When splitting nodes, randomly select m features (m ≤ M t ).

[0091] The goal of node splitting in the regression tree is to minimize the mean squared error MSE. For feature j and split threshold and R R (j, s), select the optimal split pair (j∗, s∗): (17); Among them, the actual threshold y i of scaling and blockage faults is represented by the objective function M, and the actual threshold y i of micro-leakage faults is represented by the objective function N; R L and R R are the sample sets of the left and right child nodes after splitting respectively, and c L and c R are the predicted values of the left and right child nodes respectively. That is, the target mean of the subset samples: (18); Step P3: Prediction result integration: The final output is obtained by taking the average of the predictions of all decision trees, and the uncertainty of the prediction of a single tree is reduced using ensemble learning. The final output is as follows: (19); Among them, is the average result; h t (x) is the prediction result of a single decision tree; T is the number of decision trees.

[0092] Step P4: Model performance evaluation metrics: The root mean square error (RMSE) metric is used to quantify the accuracy of predicting scaling, blockage, and micro-leakage respectively: (20); Judge whether the root mean square error of the scaling, blockage, and micro-leakage and process parameters meets the error precision requirement, where the error precision is 0.1; otherwise, return to step P1 for continuous iteration until the maximum number of iterations is reached. Step P5: Feature importance evaluation and analysis Measure the feature importance by the change in the out-of-bag (OOB) error after permuting the feature values. After randomly permuting the feature Xj, measure its importance degree by the change in the OOB error. If the error increases significantly after permutation, it indicates that the feature has an important impact on the model prediction. The importance degree is calculated as follows: (21); where, MSE t is the OOB error of the t-th tree.

[0093] Accordingly, the score rankings of the importance degrees of the scaling, blockage, and micro-leakage and process parameters are as Figure 14 shown. The relationships between the importance degrees of the scaling and blockage faults and the pressure difference, flow rate, and temperature are 0.51, 0.30, and 0.19 respectively, and are assigned to the weights of the objective functions M of the pressure difference, flow rate, and temperature for scaling and blockage; similarly, the relationships between the importance degrees of micro-leakage and humidity, flow rate, and pressure difference are 0.83, 0.10, and 0.07 respectively. Then, the weights of the objective function M of micro-leakage for humidity, flow rate, and pressure difference can be obtained.

[0094] The technical solutions in the embodiments of the present application at least have the following technical effects or advantages: 1. The detection device integrates an advanced automatic control system and can automatically complete the detection process.

[0095] 2. The device adopts infrared mass spectrometry analysis and detection technology, which can achieve high-precision and high-sensitivity measurement of various active particles in the plasma, thereby accurately calculating the dissociation rate and providing reliable data for the performance evaluation of the plasma source.

[0096] 3. The device is designed with a real-time monitoring function and can immediately feedback the dissociation state of the plasma. Through real-time monitoring, the working conditions of the plasma source can be adjusted in a timely manner to ensure the stability and consistency of the production process.

[0097] 4. The outlet of the RPS device is designed with a variable cycle heat dissipation device to solve the influence of the temperature imbalance problem on the measurement reliability of the dissociation rate.

[0098] 5. The detection device is designed with a tail gas treatment device, which can effectively remove harmful substances in the tail gas and reduce environmental pollution.

[0099] 6. The evaluation of the dissociation rate of the remote plasma source does not need to be detected in actual integrated circuit production equipment, with low cost and short cycle.

[0100] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. An electrothermal adsorption tail gas treatment device for RPS dissociation rate test, characterized in that: include: A heating system, a water vapor injection system, a cooling system and an adsorption system are connected in sequence; the heating system comprises a segmented reaction tube, and its temperature field is distributed in an increasing manner from the air inlet end to the air outlet end; the adsorption system comprises a primary solid adsorption layer and a secondary circulation spray system, and the segmented reaction tube is a three-section coaxial nested structure, including a preheating section, a main decomposition section and a deep cracking section, and each section is independently temperature-controlled and heated by a high-frequency induction coil.

2. The electrothermal adsorption tail gas treatment equipment according to claim 1, characterized in that: The water vapor injection system is an annular injection device, and the injection amount of ultrapure water vapor is controlled by a mass flow meter to dynamically match the molar ratio of NF3.

3. The electrothermal adsorption tail gas treatment equipment according to claim 1, characterized in that: A heat exchanger is provided between the outlet of the water vapor injection system and the inlet of the heating system for recovering waste heat of the exhaust gas to preheat the intake gas.

4. The electrothermal adsorption tail gas treatment equipment according to claim 1, characterized in that: The secondary circulation spraying system of the adsorption system is equipped with a pH value feedback device for dynamically adjusting the concentration and flow rate of the spraying liquid.

5. The electrothermal adsorption tail gas treatment equipment according to claim 1, characterized in that: The outlet of the water vapor injection system is also provided with a particle collection tank for capturing solid particles generated by the reaction.

6. The electrothermal adsorption tail gas treatment equipment according to claim 1, characterized in that: An emergency pressure relief valve is provided between the air inlet of the heating system and the inlet of the adsorption system, for opening and relieving pressure when the pressure exceeds a limit.

7. The electrothermal adsorption tail gas treatment equipment according to claim 1, characterized in that: It also includes a gas content detection system, which includes a NF3 detector and a HF sensor, which is used to monitor the concentration of NF3 and HF in the exhaust gas in real time and feed back to the control system to adjust the heating power and the amount of water vapor injected.

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