Plasma processing apparatus and measurement circuit
A plasma processing apparatus 10 includes a chamber 17 in which an internal space is provided and a target object carried into the internal space is processed with plasma in the internal space; a high frequency power source 14 configured to supply a high frequency power for plasma generation within the chamber 17 ; a matching circuit 15 configured to match an impedance of the plasma within the chamber 17 with an impedance of the high frequency power source 14 ; a signal synchronizer 20 configured to calculate the impedance of the plasma within the chamber 17 ; a control amount calculator 12 configured to control a frequency and a magnitude of the high frequency power, and an impedance of the matching circuit 15 based on the impedance calculated by the signal synchronizer 20 . Further, the signal synchronizer 20 and the control amount calculator 12 are provided on a single substrate 11.
1. A plasma processing apparatus, comprising:
a chamber in which an internal space is provided and a processing target object carried into the internal space is processed with a plasma generated in the internal space;
a power supply unit configured to supply a first high frequency power for plasma generation within the chamber;
a matching circuit configured to match an impedance of the plasma within the chamber with an impedance of the power supply unit;
a first calculator configured to calculate the impedance of the plasma within the chamber;
a control circuit configured to control a frequency of the first high frequency power supplied into the chamber, a magnitude of the first high frequency power, and an impedance of the matching circuit based on the impedance calculated by the first calculator; and
a first measurement unit connected to a node between the matching circuit and the chamber and configured to measure a voltage and a current of the first high frequency power supplied into the chamber,
wherein the first calculator and the control circuit are provided on a single substrate, and
the first calculator calculates the impedance of the plasma within the chamber based on the voltage and the current of the first high frequency power measured by the first measurement unit.
2. The plasma processing apparatus of claim 1 ,
wherein the first calculator includes:
a first analog to digital converter (ADC) configured to convert a voltage of the first high frequency power supplied into the chamber into a digital signal;
a second ADC configured to convert a current of the first high frequency power supplied into the chamber into a digital signal;
a second calculator configured to calculate a phase and an amplitude of the voltage converted into the digital signal and a phase and an amplitude of the current converted into the digital signal; and
a third calculator configured to calculate the impedance of the plasma within the chamber based on a phase difference and an amplitude ratio between the voltage converted into the digital signal and the current converted into the digital signal.
3. The plasma processing apparatus of claim 2 ,
wherein the first calculator further includes:
a signal generator configured to generate a sampling clock input into each of the first ADC and the second ADC;
a first phase adjusting unit configured to adjust a phase of the sampling clock input into the first ADC based on the phase of the voltage corresponding to the sampling clock; and
a second phase adjusting unit configured to adjust a phase of the sampling clock input into the second ADC based on the phase of the current corresponding to the sampling clock.
4. The plasma processing apparatus of claim 3 , wherein the first calculator further includes:
a first amplifier configured to amplify the voltage of the first high frequency power supplied into the chamber and input the amplified voltage into the first ADC;
a second amplifier configured to amplify the current of the first high frequency power supplied into the chamber and input the amplified current into the second ADC;
a first gain adjusting unit configured to adjust a gain of the first amplifier based on the amplitude of the voltage calculated by the second calculator; and
a second gain adjusting unit configured to adjust a gain of the second amplifier based on the amplitude of the current calculated by the second calculator.
5. The plasma processing apparatus of claim 2 ,
wherein the first calculator further includes:
a first amplifier configured to amplify the voltage of the first high frequency power supplied into the chamber and input the amplified voltage into the first ADC;
a second amplifier configured to amplify the current of the first high frequency power supplied into the chamber and input the amplified current into the second ADC;
a first gain adjusting unit configured to adjust a gain of the first amplifier based on the amplitude of the voltage calculated by the second calculator; and
a second gain adjusting unit configured to adjust a gain of the second amplifier based on the amplitude of the current calculated by the second calculator.
6. The plasma processing apparatus of claim 1 , further comprising:
a second measurement unit connected to a node between the power supply unit and the matching circuit and configured to measure a voltage and a current of a second high frequency power output from the power supply unit into the matching circuit,
wherein the first calculator calculates the impedance of the plasma within the chamber by further using the voltage and the current of the second high frequency power measured by the second measurement unit.
7. A measurement circuit which is provided in a plasma processing apparatus including a chamber in which an internal space is provided and a processing target object carried into the internal space is processed with a plasma generated in the internal space; a power supply unit configured to supply a high frequency power for plasma generation within the chamber; a matching circuit provided between the chamber and the power supply unit; and a control circuit configured to control a frequency of the high frequency power supplied into the chamber by the power supply unit, a magnitude of the high frequency power, and an impedance of the matching circuit and which is configured to measure an impedance of the plasma within the chamber,
wherein the measurement circuit is provided on a single substrate together with the control circuit, and
the measurement circuit includes:
a first analog to digital converter (ADC) configured to convert a voltage of the high frequency power supplied into the chamber into a digital signal;
a second ADC configured to convert a current of the high frequency power supplied into the chamber into a digital signal;
an amplitude/phase calculator configured to calculate a phase and an amplitude of the voltage converted into the digital signal and a phase and an amplitude of the current converted into the digital signal; and
an impedance calculator configured to calculate the impedance of the plasma within the chamber based on a phase difference and an amplitude ratio between the voltage converted into the digital signal and the current converted into the digital signal.
8. A plasma processing apparatus, comprising:
a chamber in which an internal space is provided and a processing target object carried into the internal space is processed with a plasma generated in the internal space;
a power supply unit configured to supply a first high frequency power for plasma generation within the chamber;
a matching circuit configured to match an impedance of the plasma within the chamber with an impedance of the power supply unit;
a first calculator configured to calculate the impedance of the plasma within the chamber; and
a control circuit configured to control a frequency of the first high frequency power supplied into the chamber, a magnitude of the first high frequency power, and an impedance of the matching circuit based on the impedance calculated by the first calculator,
wherein the first calculator and the control circuit are provided on a single substrate, and
wherein the first calculator includes:
a first analog to digital converter (ADC) configured to convert a voltage of the first high frequency power supplied into the chamber into a digital signal;
a second ADC configured to convert a current of the first high frequency power supplied into the chamber into a digital signal;
a second calculator configured to calculate a phase and an amplitude of the voltage converted into the digital signal and a phase and an amplitude of the current converted into the digital signal; and
a third calculator configured to calculate the impedance of the plasma within the chamber based on a phase difference and an amplitude ratio between the voltage converted into the digital signal and the current converted into the digital signal.
9. The plasma processing apparatus of claim 8 , wherein the first calculator further includes:
a signal generator configured to generate a sampling clock input into each of the first ADC and the second ADC;
a first phase adjusting unit configured to adjust a phase of the sampling clock input into the first ADC based on the phase of the voltage corresponding to the sampling clock; and
a second phase adjusting unit configured to adjust a phase of the sampling clock input into the second ADC based on the phase of the current corresponding to the sampling clock.
10. The plasma processing apparatus of claim 9 , wherein the first calculator further includes:
a first amplifier configured to amplify the voltage of the first high frequency power supplied into the chamber and input the amplified voltage into the first ADC;
a second amplifier configured to amplify the current of the first high frequency power supplied into the chamber and input the amplified current into the second ADC;
a first gain adjusting unit configured to adjust a gain of the first amplifier based on the amplitude of the voltage calculated by the second calculator; and
a second gain adjusting unit configured to adjust a gain of the second amplifier based on the amplitude of the current calculated by the second calculator.
11. The plasma processing apparatus of claim 8 , wherein the first calculator further includes:
a first amplifier configured to amplify the voltage of the first high frequency power supplied into the chamber and input the amplified voltage into the first ADC;
a second amplifier configured to amplify the current of the first high frequency power supplied into the chamber and input the amplified current into the second ADC;
a first gain adjusting unit configured to adjust a gain of the first amplifier based on the amplitude of the voltage calculated by the second calculator; and
a second gain adjusting unit configured to adjust a gain of the second amplifier based on the amplitude of the current calculated by the second calculator.
12. The plasma processing apparatus of claim 8 , further comprising:
a second measurement unit connected to a node between the power supply unit and the matching circuit and configured to measure a voltage and a current of a second high frequency power output from the power supply unit into the matching circuit,
wherein the first calculator calculates the impedance of the plasma within the chamber by further using the voltage and the current of the second high frequency power measured by the second measurement unit.