# US 2021/0280401 A1 · Inspection method and plasma processing apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0280401 A1 - Document ID: US20210280401A1 - Status: Published application - Kind: A1 - Application number: 17/193,205 - Filed: 2021-03-05 - Published: 2021-09-09 - Earliest claimed: 2020-03-09 - Assignees: Tokyo Electron Limited - Applicants: Tokyo Electron Limited - Inventors: Yusuke HIRAYAMA; Shu KUSANO - Web page: https://patentgrep.com/patent/US20210280401A1 ## CPC - H01J 37/32935: {Monitoring and controlling tubes by information coming from the object and/or discharge} - H01J 37/32183: {Matching circuits} - H01J 37/32311: {Circuits specially adapted for controlling the microwave discharge} - H01J 2237/24564: Measurements of electric or magnetic variables, e.g. voltage, current, frequency - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract An inspection method is provided. The inspection method includes monitoring power of a reflected wave of a power wave supplied from a source power supply for generation of plasma in a plasma processing apparatus, and obtaining a fluctuation amount of a measured value within a period after initiation of the supply of the power wave. The fluctuation amount the measured value is a fluctuation amount indicating a fluctuation in a peak-to-peak voltage at a lower electrode of the substrate support in the chamber or a fluctuation amount indicating a fluctuation in impedance of a load including the lower electrode. ## Claims ### Claim 1 An inspection method comprising: monitoring power of a reflected wave of a power wave supplied from a source power supply for generation of plasma in a plasma processing apparatus, wherein the power wave is a radio frequency wave or a microwave, the plasma processing apparatus comprises a chamber and a substrate support configured to support a substrate in the chamber, and the substrate support comprises a lower electrode; and obtaining a fluctuation amount of a measured value within a period after initiation of the supply of the power wave, wherein the fluctuation amount of the measured value is a fluctuation amount indicating a fluctuation in a peak-to-peak voltage at the lower electrode or a fluctuation amount indicating a fluctuation in impedance of a load including the lower electrode. ### Claim 2 (depends on 1) The inspection method of claim 1, wherein the period is a period after the power of the reflected wave has decreased to an allowable range. ### Claim 3 (depends on 1) The inspection method of claim 1, further comprising determining whether the fluctuation amount of the measured value satisfies an allowable condition. ### Claim 4 (depends on 3) The inspection method of claim 3, wherein the allowable condition is satisfied when a ratio of the fluctuation amount of the measured value to an average value of the measured value within the period is included within another allowable range. ### Claim 5 (depends on 1) The inspection method of claim 1, wherein the fluctuation amount of the measured value is a difference between a maximum value of the measured value and a minimum value of the measured value within the period. ### Claim 6 A plasma processing apparatus comprising: a chamber; a substrate support comprising a lower electrode and configured to support a substrate in the chamber; a source power supply configured to supply a power wave for generation of plasma from gas in the chamber, wherein the power wave is a radio frequency wave or a microwave; a matching unit connected between the chamber and the source power supply; a measuring unit configured to measure power of a reflected wave of the power wave; and a control unit, wherein the control unit is configured to obtain a fluctuation amount of a measured value within a period after initiation of the supply of the power wave, and the fluctuation amount of the measured value is a fluctuation amount indicating a fluctuation in peak-to-peak voltage at the lower electrode or a fluctuation amount indicating a fluctuation in impedance of a load including the lower electrode. ### Claim 7 (depends on 6) The plasma processing apparatus of claim 6, wherein the control unit is configured to obtain the fluctuation amount of the measured value within the period after the power of the reflected wave has decreased to an allowable range. ### Claim 8 (depends on 6) The plasma processing apparatus of claim 6, wherein the control unit is configured to determine whether the fluctuation amount of the measured value satisfies an allowable condition. ### Claim 9 (depends on 8) The plasma processing apparatus of claim 8, wherein the control unit is configured to determine that the allowable condition is satisfied when a ratio of the fluctuation amount of the measured value to an average value of the measured values within the period is included within another allowable range. ### Claim 10 (depends on 6) The plasma processing apparatus of claim 6, wherein the control unit is configured to obtain a difference between a maximum value of the measured value and a minimum value of the measured value within the period as the fluctuation amount of the measured value. ### Claim 11 (depends on 6) The plasma processing apparatus of claim 6, further comprising: a bias power supply electrically connected to the lower electrode; a matching unit connected between the lower electrode and the bias power supply; and a sensor configured to measure the impedance, wherein the impedance is impedance of a load of the bias power supply. ### Claim 12 (depends on 6) The plasma processing apparatus of claim 6, further comprising a sensor configured to measure a voltage at the lower electrode, wherein the control unit is configured to acquire the peak-to-peak voltage from the voltage measured by the sensor. ### Claim 13 (depends on 6) The plasma processing apparatus of claim 6, further comprising an upper electrode provided above the lower electrode, wherein the source power supply is electrically connected to the upper electrode.