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CN-122028286-A - Online monitoring device and method for plasma voltage characteristics

CN122028286ACN 122028286 ACN122028286 ACN 122028286ACN-122028286-A

Abstract

The embodiment of the application provides an on-line monitoring device and method for plasma voltage characteristics, wherein the device comprises a detection handle assembly, a shielding cable and a monitoring host, a signal processing module with an alternating-current amplitude-frequency characteristic compensation resistance-capacitance voltage division and operational amplification framework is adopted, a full-range linear non-stepping ADC sampling module is matched, and a sliding window type transient voltage capturing algorithm is combined to realize the acquisition, processing and monitoring of plasma voltage signals. According to the embodiment of the application, full-range high-precision online detection of the plasma voltage characteristic in the bandwidth of-500V to +500V and 0-2 MHz can be realized through the technical scheme, data support is provided for performance calibration and closed-loop adjustment of plasma cleaning equipment, and the risk of electric damage to a workpiece in the plasma cleaning process is greatly reduced.

Inventors

  • XIAO QIUGUI
  • FU XIAOFEN
  • ZHANG QIUHUA

Assignees

  • 深圳市研成工业技术股份有限公司

Dates

Publication Date
20260512
Application Date
20260323

Claims (10)

  1. 1. The on-line monitoring device for the plasma voltage characteristics is characterized by comprising a detection handle assembly, a shielding cable and a monitoring host; the detection handle assembly comprises an insulating handle, a plasma receiving plate and a heat-resistant insulating piece, wherein the plasma receiving plate is used for receiving plasma jet flow in a non-contact mode to couple voltage signals of the plasma jet flow, the plasma receiving plate is attached to the upper surface of the heat-resistant insulating piece, and the heat-resistant insulating piece is fixedly connected with the insulating handle; the shielding cable is electrically connected between the plasma receiving plate and the monitoring host; The monitoring host is provided with an ADC sampling module, a signal processing module and a microprocessor, wherein the signal processing module comprises a resistance-capacitance voltage dividing unit and an operational amplification unit; the resistance-capacitance voltage dividing unit comprises a voltage dividing upper arm resistor And voltage dividing lower arm resistor And a voltage-dividing upper arm compensation capacitor C in1 and a voltage-dividing lower arm compensation capacitor C in2 for compensating the AC amplitude-frequency characteristic, wherein the voltage-dividing upper arm resistor Is connected with the plasma receiving plate, and the output end is connected with the voltage dividing lower arm resistor The input end of the shielding cable is connected with the input end of the shielding cable, the equivalent resistance of the shielding cable is Rs, the equivalent capacitance of the shielding cable is Cs, and the compensation unit meets the amplitude-frequency characteristic compensation formula: ×C in2 = X (Cs+C in1 ), the voltage dividing resistance satisfies +Rs>> 。
  2. 2. The apparatus for on-line monitoring of plasma voltage characteristics according to claim 1, wherein, The voltage dividing upper arm resistor Is electrically connected with the output end of the shielding cable, and divides the upper arm resistor The other end of (a) is respectively connected with the voltage dividing lower arm resistor Is electrically connected with the input end of the operational amplification unit, and is divided into a lower arm resistor The other end of the first electrode is grounded; The voltage-dividing upper arm compensation capacitor C in1 and the voltage-dividing upper arm resistor The voltage-dividing lower arm compensation capacitor C in2 is connected in parallel with the voltage-dividing lower arm resistor Parallel connection; Wherein the voltage dividing upper arm resistor Voltage dividing lower arm resistor The cable equivalent resistance Rs satisfies the following relationship: 。
  3. 3. The on-line monitoring device for plasma voltage characteristics according to claim 2, wherein the operational amplification unit comprises an operational amplifier U1.1, a feedback resistor R4, a gain resistor R5 and a matching resistor R3, wherein the non-inverting input end of the operational amplifier U1.1 is electrically connected with the output end of the resistance-capacitance voltage division unit, the inverting input end is respectively electrically connected with one end of the feedback resistor R4 and one end of the gain resistor R5, the other end of the feedback resistor R4 is grounded, the other end of the gain resistor R5 is electrically connected with the output end of the operational amplifier U1.1, and the matching resistor R3 is connected in series between the non-inverting input end of the operational amplifier U1.1 and the output end of the resistance-capacitance voltage division unit; The output voltage of the operational amplification unit Input voltage collected by plasma receiving plate The following relation is satisfied: 。
  4. 4. The plasma voltage characteristic on-line monitoring device according to claim 3, wherein the equivalent resistance of the shield cable Far less than the voltage-dividing upper arm resistance The output voltage of the operational amplifier unit Input voltage collected by plasma receiving plate The following relation is further satisfied: 。
  5. 5. The on-line monitoring device for plasma voltage characteristics according to claim 1, wherein the plasma receiving plate is a metal plate plated with nickel on the surface of a brass base material, the heat-resistant insulating member is an alumina ceramic material, the detection surface of the plasma receiving plate is arranged opposite to the nozzle of the plasma cleaning equipment, the detection interval is 2 mm-20 mm, and the on-line monitoring device further comprises a grounding terminal for being connected to the grounding end of the plasma cleaning equipment.
  6. 6. The on-line monitoring device for the plasma voltage characteristics according to claim 1, wherein the signal processing module has the characteristics of high input impedance and low input capacitance, the input impedance is more than or equal to 10 8 ohms, the input capacitance is less than or equal to 10pF, the sampling bandwidth of the signal processing module is 0-2 MHz, the voltage measuring range is-500V to +500V, and the ADC sampling module adopts a full-range linear non-step sampling architecture.
  7. 7. The on-line plasma voltage characteristic monitoring device according to claim 6, wherein a transient voltage capturing algorithm is configured in the microprocessor, and the algorithm performs the steps of: And carrying out sliding window sequencing on the voltage values of the continuous N sampling points by taking the sampling period of the ADC sampling module as a unit, extracting voltage peaks and valleys in the window, respectively comparing the peaks and the valleys with extreme values of the previous window, and marking as transient voltage events and storing complete sampling data at corresponding moments when the differences exceed a preset threshold value, wherein N is a positive integer and satisfies Nyquist sampling points corresponding to sampling bandwidths of which N is more than or equal to 2 times.
  8. 8. The on-line monitoring device of plasma voltage characteristics according to claim 7, wherein the microprocessor comprises a storage module and a display module, the storage module is used for storing a maximum voltage value, a minimum voltage value and a transient voltage extremum acquired within a preset time period, and the display module is used for displaying a plasma voltage waveform and an acquired numerical value.
  9. 9. The on-line monitoring device of claim 1, further comprising a high voltage protection circuit having an input connected to the plasma receiving board and an output connected to the signal processing module for clamping the input of the signal processing module to a safe voltage range when receiving a transient high voltage exceeding a preset threshold.
  10. 10. An online monitoring method for plasma voltage characteristics, characterized in that the online monitoring method is realized based on the online monitoring device for plasma voltage characteristics according to any one of claims 1 to 9, and comprises the following steps: the detection surface of the plasma receiving plate is opposite to the center of a nozzle of the plasma cleaning equipment, the detection distance is adjusted to 2 mm-20 mm, and the plasma receiving plate is electrically connected with a monitoring host through a shielding cable; starting the plasma cleaning equipment, and enabling the plasma jet ejected by the nozzle to face the plasma receiving plate; the monitoring host collects signals, analyzes and processes the signals, and displays real-time voltage characteristic data of the plasma through the display module.

Description

Online monitoring device and method for plasma voltage characteristics Technical Field The invention relates to the technical field of plasma detection, in particular to an on-line monitoring device and method for plasma voltage characteristics. Background The plasma treatment technology is widely applied to surface cleaning and modification treatment processes of workpieces such as PCBs, PCBA, semiconductor wafers, glass and the like by virtue of the advantages of high cleaning efficiency, no secondary pollution and wide adaptation materials. However, under the influence of equipment operation parameters and environmental factors, plasma generated by a nozzle of the plasma cleaning equipment is easy to deviate from electric neutrality to form alternating voltage with specific frequency characteristics, even transient second-level transient impulse voltage with higher inclusion amplitude, and irreversible electric damage is caused to a workpiece with high sensitivity to electric characteristics. It should be noted that the foregoing is not necessarily prior art, and is not intended to limit the scope of the present application. Disclosure of Invention The embodiment of the application provides an on-line monitoring device and an on-line monitoring method for plasma voltage characteristics, which are used for solving or relieving one or more of the technical problems. As a first aspect of the embodiments of the present application, the embodiments of the present application provide an online monitoring device for plasma voltage characteristics, including a detection handle assembly, a shielding cable, and a monitoring host; the detection handle assembly comprises an insulating handle, a plasma receiving plate and a heat-resistant insulating piece, wherein the plasma receiving plate is used for receiving plasma jet flow in a non-contact mode to couple voltage signals of the plasma jet flow, the plasma receiving plate is attached to the upper surface of the heat-resistant insulating piece, and the heat-resistant insulating piece is fixedly connected with the insulating handle; the shielding cable is electrically connected between the plasma receiving plate and the monitoring host; The monitoring host is provided with an ADC sampling module, a signal processing module and a microprocessor, wherein the signal processing module comprises a resistance-capacitance voltage dividing unit and an operational amplification unit; The resistive-capacitive voltage dividing unit comprises a voltage dividing upper arm resistor And voltage dividing lower arm resistorAnd a voltage-dividing upper arm compensation capacitor C in1 and a voltage-dividing lower arm compensation capacitor C in2 for compensating the alternating-current amplitude-frequency characteristic, wherein the voltage-dividing upper arm resistorIs connected with the plasma receiving plate, and the output end is connected with the voltage dividing arm resistorThe input end of the shielding cable is connected, the equivalent resistance of the shielding cable is Rs, the equivalent capacitance of the shielding cable is Cs, and the compensation unit meets the amplitude-frequency characteristic compensation formula:×=×(Cs+ ) The voltage dividing resistance satisfies +Rs>>。 In one embodiment, the voltage dividing upper arm resistorIs electrically connected with the output end of the shielding cable, and divides the upper arm resistorThe other end of (a) is respectively connected with the voltage dividing lower arm resistorIs electrically connected with the input end of the operational amplification unit, and is divided into a lower arm resistorThe other end of the first electrode is grounded; Divided upper arm compensation capacitor C in1 and divided upper arm resistor Parallel connection, voltage division lower arm compensation capacitor C in2 and voltage division lower arm resistorParallel connection; wherein the voltage dividing upper arm resistor Voltage dividing lower arm resistorThe cable equivalent resistance Rs satisfies the following relationship: 。 In one embodiment, the operational amplification unit comprises an operational amplifier U1.1, a feedback resistor R4, a gain resistor R5 and a matching resistor R3, wherein the non-inverting input end of the operational amplifier U1.1 is electrically connected with the output end of the resistive-capacitive voltage division unit, the inverting input end of the operational amplifier U1.1 is respectively electrically connected with one end of the feedback resistor R4 and one end of the gain resistor R5, the other end of the feedback resistor R4 is grounded, the other end of the gain resistor R5 is electrically connected with the output end of the operational amplifier U1.1, and the matching resistor R3 is connected in series between the non-inverting input end of the operational amplifier U1.1 and the output end of the resistive-capacitive voltage division unit; Output voltage of operational amplification unit Inpu