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CN-122018580-A - Closed-loop control device and control process for high-temperature nitriding atmosphere concentration

CN122018580ACN 122018580 ACN122018580 ACN 122018580ACN-122018580-A

Abstract

The invention discloses a closed-loop control device and a control process for high-temperature nitriding atmosphere concentration, the device comprises a nitriding atmosphere supply module, a flow regulating module, a reaction device, a concentration detection module, a cooling device, a tail gas treatment device, a controller and an auxiliary detection module. The concentration detection module is arranged at the tail end of the reaction device to collect nitrogen concentration signals in real time, and the pressure and temperature signals collected by the auxiliary detection module are combined and processed by the controller with the built-in PID regulation algorithm to feed back and regulate the air inlet flow of the flow regulation module, so that a flow-nitrogen concentration double closed-loop control system is formed. The invention solves the problems of low control precision, poor stability and weak anti-interference capability of the nitrogen concentration of the existing open-loop control device, can ensure that the nitrogen concentration of the surface of the material is stabilized in an effective nitriding zone, and is suitable for various nitriding process scenes such as material nitriding, semiconductor device preparation and the like.

Inventors

  • ZHANG ZHUWU
  • LI GAOXU

Assignees

  • 福州大学

Dates

Publication Date
20260512
Application Date
20260202

Claims (10)

  1. 1. The high-temperature nitriding atmosphere concentration closed-loop control device is characterized by comprising a nitriding atmosphere supply module (1-6), a flow regulating module (7-9), a reaction device (11), a concentration detection module (15-16), a cooling device (17) and a tail gas treatment device (19) which are connected in sequence; The nitriding atmosphere supply module (1-6) is used for providing high-purity ammonia, nitrogen and argon, and the air outlet end of the nitriding atmosphere supply module is connected with the air inlet end of the flow regulating module (7-9) through an air inlet pipeline; The flow regulating module (7-9) is used for regulating the proportion of gas entering the reaction device (11) and the flow of the gas, the gas outlet end of the flow regulating module is connected with the gas inlet of the reaction device (11) through a gas inlet pipeline, and the signal output end of the flow regulating module (7-9) is electrically connected with the controller (22) and is used for collecting the actual gas inlet flow signal in real time; A reaction device (11) which is used as a nitriding reaction place of a workpiece to be treated, the tail end of which is provided with an exhaust port, and the inside of which is provided with an auxiliary detection module (12-13); The concentration detection module (15-16) is arranged at the exhaust port of the reaction device (11) and is used for detecting the nitrogen concentration in the exhaust gas at the tail end of the reaction device (11) in real time, and the signal output end of the concentration detection module is electrically connected with the signal input end of the controller (22); the air inlet end of the cooling device (17) is connected with the air outlet end of the reaction device (11) through an exhaust pipeline and an outlet valve (14) and is used for cooling high-temperature mixed gas discharged by the reaction device (11); The tail gas treatment device (19) is connected with the air outlet end of the cooling device (17) through an exhaust pipeline and a check valve (18) at the air inlet end, and is used for absorbing and exhausting harmful gases in the gas, and an exhaust valve (20) is connected at the tail end and is used for exhausting the harmless gases; The auxiliary detection module (12-13) comprises a pressure sensor (12) and a temperature sensor (13) and is used for collecting pressure and temperature signals in the reaction device (11) in real time, and signal output ends of the auxiliary detection module are electrically connected with the controller (22); The controller (22) is internally provided with a PID regulating algorithm, the signal input end of the controller is respectively and electrically connected with the concentration detection module (15-16) and the auxiliary detection module (12-13), the signal output end is respectively and electrically connected with the flow regulating module (7-9) and the reaction device (11), and the controller is used for receiving an actual nitrogen concentration signal, a pressure signal and a temperature signal, and outputting a flow regulating signal to the flow regulating module (7-9) after comparing and calculating with a preset concentration value; The controller (22) combines the nitrogen concentration signal acquired by the concentration detection module (15-16), the pressure and temperature signal acquired by the auxiliary detection module (12-13) and the actual air inlet flow signal acquired by the flow regulation module (7-9) to form a flow-nitrogen concentration double closed loop control system, and the air inlet flow of the flow regulation module (7-9) is regulated in a feedback mode.
  2. 2. The high-temperature nitriding atmosphere concentration closed-loop control device according to claim 1, wherein the nitriding atmosphere supply modules (1-6) comprise an ammonia storage tank (1), a nitrogen storage tank (3), an argon storage tank (5) and three corresponding pressure reducing valves, the air outlet ends of the storage tanks are respectively connected with the corresponding pressure reducing valves to realize pressure regulation, and the pressure reducing valves are electrically connected with the controller (22).
  3. 3. The closed-loop control device for the concentration of the high-temperature nitriding atmosphere according to claim 1, wherein the flow rate adjusting module (7-9) adopts a gas flow rate controller so as to realize flow rate adjustment with the accuracy of +/-0.1% according to a control signal.
  4. 4. The closed-loop control device for the concentration of the high-temperature nitriding atmosphere according to claim 1, wherein the concentration detection module (15-16) adopts a high-precision nitrogen sensor (16), and the detection precision of the high-precision nitrogen sensor (16) is +/-0.1%vol within a detection range of 0-100%vol.
  5. 5. The high-temperature nitriding atmosphere concentration closed-loop control device according to claim 1, wherein the controller (22) is further connected with a human-computer interaction unit (21), and the human-computer interaction unit (21) comprises a touch screen and keys, and is used for setting nitriding gas proportion, nitriding gas flow, preset nitrogen concentration value and temperature curve, and displaying actual nitrogen concentration, flow, pressure and temperature parameters.
  6. 6. The high-temperature nitriding atmosphere concentration closed-loop control device according to claim 1, wherein the controller (22) is further connected with an alarm unit (23), the alarm unit (23) comprises an audible and visual alarm, and when the nitrogen concentration deviates from a preset range by +/-5%, the pressure exceeds the preset range or equipment fails, the controller (22) triggers the alarm unit (23) to send an alarm signal.
  7. 7. The closed-loop control device for the concentration of the high-temperature nitriding atmosphere according to claim 1, wherein the controller (22) performs a comparison operation with a preset concentration value after performing compensation correction on an actual nitrogen concentration signal transmitted by the concentration detection module (15-16) according to pressure and temperature signals acquired by the auxiliary detection module (12-13).
  8. 8. The closed-loop control process for the concentration of the high-temperature nitriding atmosphere is characterized by comprising the following steps of: Step S1, initializing, namely setting target nitrogen concentration, a temperature curve and pressure parameters of the surface of a material through a human-computer interaction unit (21), calculating the inlet flow of each component of the initial mixed gas according to the target nitrogen concentration by a controller (22), outputting a control signal to a flow regulating module (7-9), and controlling ammonia, nitrogen and argon to enter a reaction device (11) in proportion; S2, real-time multi-parameter detection, namely collecting nitrogen concentration signals in exhaust gas at the tail end of the reaction device (11) through a concentration detection module (15-16), collecting actual inlet air flow signals of all components through a flow regulation module (7-9), collecting pressure and temperature signals in the reaction device (11) through an auxiliary detection module (12-13), and transmitting all detection signals to a controller (22) in real time; Step S3, signal compensation and deviation calculation, wherein the controller (22) compensates and corrects the nitrogen concentration detection value according to the detection values of the pressure sensor (12) and the temperature sensor (13), compares the corrected actual nitrogen concentration value with the tail end concentration value corresponding to the target nitrogen concentration, and calculates the concentration deviation; step S4, PID feedback adjustment, wherein the controller (22) calculates the concentration deviation through a built-in PID adjustment algorithm, and outputs a control signal to the flow adjustment module (7-9) in combination with an actual air inlet flow signal to accurately adjust the air inlet flow of each component; Step S5, continuously performing closed-loop control, repeating the steps S2-S4, and maintaining the nitrogen concentration of the surface of the material in the reaction device (11) to be stable in a target range through real-time detection and dynamic adjustment; The process realizes high-precision dynamic regulation and control of the concentration of the nitriding atmosphere through a flow-nitrogen concentration double closed-loop control logic.
  9. 9. The closed-loop control process for the concentration of the high-temperature nitriding atmosphere according to claim 8, further comprising an abnormality alarming step, wherein when the concentration, the pressure or the temperature of nitrogen exceeds a preset range, the controller (22) triggers the alarm unit (23) to give an audible and visual alarm and display a fault prompt, and simultaneously automatically adjusts the flow parameters to try to restore to a normal state.
  10. 10. The closed-loop control process for the concentration of the high-temperature nitriding atmosphere according to claim 8, further comprising a tail gas treatment step, wherein the mixed gas discharged from the reaction device (11) is cooled by the cooling device (17), and then enters the tail gas treatment device (19) to absorb harmful gases of ammonia and hydrogen, and the treated harmless gases of the nitrogen and the argon are discharged through the exhaust valve (20).

Description

Closed-loop control device and control process for high-temperature nitriding atmosphere concentration Technical Field The invention relates to the technical field of material surface treatment and semiconductor manufacturing, in particular to a high-temperature nitriding atmosphere concentration closed-loop control device and a control process of a material nitriding process. Background In the industrial processes of material nitriding treatment, semiconductor device preparation and the like, the stability of the nitrogen concentration on the surface of the material directly determines the performance index of the product. For example, in the nitriding process of metal materials, the fluctuation of the nitrogen concentration on the surface of the metal materials along with time can lead to the improvement of the porosity of the surface of the materials, the disordered growth of a compound layer, the uneven hardness of the surface of the materials and the deviation of the thickness of a nitriding layer, and in the depositing process of the silicon nitride film manufactured by semiconductors, the instability of the nitrogen concentration on the surface of the materials can influence the compactness and the electrical property of the film, thereby leading to the reduction of the yield of devices. The existing nitriding atmosphere control device mostly adopts an open-loop control mode, namely, the air inlet flow is set according to preset technological parameters, and the nitrogen concentration change in the reactor and the nitrogen concentration change on the surface of the material cannot be responded in real time. Because the nitrogen concentration on the surface of the material is in a dynamic change state in the reaction process, the open loop control is difficult to maintain the constant concentration of the nitriding atmosphere. Disclosure of Invention Aiming at the defects of the prior art, the invention aims to provide a closed-loop control device and a control process for the concentration of high-temperature nitriding atmosphere, the device collects nitrogen concentration signals in real time by arranging a concentration detection module at the tail end of a reaction device, and the flow regulating module is used for feeding back and regulating the air inlet after being processed by the controller, so that the dynamic closed-loop control of the concentration of the nitriding atmosphere is realized, and the nitrogen concentration of the surface of the material in the reaction device is ensured to be stabilized in an effective nitriding zone. In order to achieve the above purpose, the invention adopts the following technical scheme: the high-temperature nitriding atmosphere concentration closed-loop control device is characterized by comprising a nitriding atmosphere supply module, a flow regulating module, a reaction device, a concentration detection module, a cooling device and a tail gas treatment device which are connected in sequence; The nitriding atmosphere supply module is used for providing high-purity ammonia, nitrogen and argon, and the air outlet end of the nitriding atmosphere supply module is connected with the air inlet end of the flow regulating module through an air inlet pipeline; The flow regulating module is used for regulating the proportion of gas entering the reaction device and the flow of the gas, the gas outlet end of the flow regulating module is connected with the gas inlet of the reaction device through a gas inlet pipeline, and the signal output end of the flow regulating module is electrically connected with the controller and is used for collecting actual gas inlet flow signals in real time; The reaction device is used as a nitriding reaction place of a workpiece to be treated, the tail end of the reaction device is provided with an exhaust port, and an auxiliary detection module is arranged in the reaction device; The concentration detection module is arranged at the exhaust port of the reaction device and is used for detecting the nitrogen concentration in the exhaust gas at the tail end of the reaction device in real time, and the signal output end of the concentration detection module is electrically connected with the signal input end of the controller; the air inlet end of the cooling device is connected with the air outlet end of the reaction device through an exhaust pipeline and an outlet valve and is used for cooling high-temperature mixed gas discharged by the reaction device; the tail gas treatment device is characterized in that an air inlet end of the tail gas treatment device is connected with an air outlet end of the cooling device through an exhaust pipeline and a check valve and is used for absorbing and exhausting harmful gases in the gas, and an exhaust valve is connected to the tail end of the tail gas treatment device and is used for exhausting the harmless gases; the auxiliary detection module comprises a pressure sensor and a temperature sensor a