Monitoring a discharge in a plasma process
First Claim
1. A method of monitoring a discharge in a plasma process, the method comprising:
- supplying a plasma process with a periodic power supply signal;
determining a first power supply signal waveform in a first time interval within a first period of the power supply signal;
determining a second power supply signal waveform in a second time interval within a second period of the power supply signal, wherein the second time interval is at a position within the second period corresponding to a position of the first time interval within the first period;
comparing the second power supply signal waveform of the second time interval with a reference signal waveform associated with the first power supply signal waveform of the first time interval to thereby obtain a first comparison result;
if the first comparison result corresponds to a given first comparison result, time-shifting one of the second power supply signal waveform and the reference signal waveform, and comparing the time-shifted signal waveform with the other one of the second power supply signal waveform and the reference signal waveform that was not time-shifted to thereby obtain a second comparison result; and
generating an arc detection signal indicating an arc is present in the plasma process if the first comparison result corresponds to the first given comparison result and the second comparison result corresponds to a second given comparison result, respectively.
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Accused Products
Abstract
Systems and methods of monitoring a discharge in a plasma process are disclosed. The methods include supplying the plasma process with a periodic power supply signal, determining a first signal waveform in a first time interval within a first period of the power supply signal, determining a second signal waveform in a second time interval within a second period of the power supply signal, the second time interval being at a position within the second period corresponding to a position of the first time interval within the first period, comparing the second signal waveform with a reference signal waveform to obtain a first comparison result, determining that the first comparison result corresponds to a given first comparison result, and in response, time-shifting one of the second signal waveform and the reference signal waveform, and comparing the time-shifted signal waveform with the non-time-shifted signal waveform to obtain a second comparison result.
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Citations
19 Claims
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1. A method of monitoring a discharge in a plasma process, the method comprising:
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supplying a plasma process with a periodic power supply signal; determining a first power supply signal waveform in a first time interval within a first period of the power supply signal; determining a second power supply signal waveform in a second time interval within a second period of the power supply signal, wherein the second time interval is at a position within the second period corresponding to a position of the first time interval within the first period; comparing the second power supply signal waveform of the second time interval with a reference signal waveform associated with the first power supply signal waveform of the first time interval to thereby obtain a first comparison result; if the first comparison result corresponds to a given first comparison result, time-shifting one of the second power supply signal waveform and the reference signal waveform, and comparing the time-shifted signal waveform with the other one of the second power supply signal waveform and the reference signal waveform that was not time-shifted to thereby obtain a second comparison result; and generating an arc detection signal indicating an arc is present in the plasma process if the first comparison result corresponds to the first given comparison result and the second comparison result corresponds to a second given comparison result, respectively. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of monitoring a discharge in a plasma process, the method comprising:
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supplying a plasma process with a periodic power supply signal; determining a first power supply signal waveform in a first time interval within a first period of the power supply signal; determining a second power supply signal waveform in a second time interval within a second period of the power supply signal, wherein the second time interval is at a position within the second period corresponding to a position of the first time interval within the first period; comparing the second power supply signal waveform of the second time interval with a reference signal waveform associated with the first power supply signal waveform of the first time interval to thereby obtain a first comparison result; if the first comparison result corresponds to a given first comparison result, time-shifting one of the second power supply signal waveform and the reference signal waveform in a first direction, and comparing the time-shifted signal waveform with the other one of the second power supply signal waveform and the reference signal waveform that was not time-shifted to thereby obtain a second comparison result; time-shifting the signal waveform that was time-shifted in a second direction opposite to the first direction; and comparing the time-shifted signal waveform in the second direction to the other signal waveform that was not time-shifted to thereby obtain a third comparison result. - View Dependent Claims (8)
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9. A method of monitoring a discharge in a plasma process, the method comprising:
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supplying a plasma process with a periodic power supply signal; determining a first power supply signal waveform in a first time interval within a first period of the power supply signal; determining a second power supply signal waveform in a second time interval within a second period of the power supply signal, wherein the second time interval is at a position within the second period corresponding to a position of the first time interval within the first period; comparing the second power supply signal waveform of the second time interval with a reference signal waveform associated with the first power supply signal waveform of the first time interval to thereby obtain a first comparison result; if the first comparison result corresponds to a given first comparison result, time-shifting one of the second power supply signal waveform and the reference signal waveform, and comparing the time-shifted signal waveform with the other one of the second power supply signal waveform and the reference signal waveform that was not time-shifted to thereby obtain a second comparison result; and determining the reference signal waveform by one of; multiplying the first power supply signal waveform in the first interval with a given value, and adding or subtracting a constant value from the first power supply signal waveform in the first interval.
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10. A monitoring device for monitoring a discharge in a plasma process supplied by a power supply signal, comprising:
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a first determining device arranged to determine a first power supply signal waveform within a first time interval within a first period of the power supply signal; a second determining device arranged to determine a second power supply signal waveform within a second time interval within a second period of the power supply signal, wherein the second time interval is at a position in the second period corresponding to a position of the first time interval within the first period; a first comparator arranged to compare the second power supply signal waveform of the second time interval with a reference signal waveform associated with the first power supply signal waveform of the first time interval and determining a first comparison result; a first time-shifter arranged to time-shift one of the second power supply signal waveform and the reference signal waveform; and a second comparator arranged to compare the time-shifted signal with the other one of the second power supply signal waveform and the reference signal waveform that was not time-shifted and determining a second comparison result. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A plasma process system comprising:
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a power supply configured to supply power to a plasma process with a periodic power supply signal; and a plasma discharge monitor configured to monitor a discharge in the plasma process, comprising; a first determining device configured to determine a first power supply signal waveform within a first time interval within a first period of the power supply signal; a second determining device configured to determine a second power supply signal waveform within a second time interval within a second period of the power supply signal, wherein the second time interval is at a position in the second period that corresponds to a position of the first time interval within the first period; a first comparator configured to compare the second power supply signal waveform of the second time interval with a reference signal waveform associated with the first power supply signal waveform of the first time interval and determining a first comparison result; a first time-shifter configured to time-shift one of the second power supply signal waveform and the reference signal waveform; and a second comparator configured to compare the time-shifted signal with the other one of the second power supply signal waveform and the reference signal waveform that was not time-shifted and determining a second comparison result.
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Specification