| 摘要 |
PROBLEM TO BE SOLVED: To provide a plasma processing device equipped with a phase adjusting circuit to adjust the voltage phase of two high frequency power supplies, in which the sensing accuracy of the phase difference is enhanced so as to comply with a wide frequency range by eliminating discontinuity generated at the time of analog control. SOLUTION: Sensing signals S2 and S3 input to a phase difference sensing circuit 45 are multiplied by a phase difference signal S1 of the second waveform synthesizing circuit 44 and are passed through a filter so as to get rid of the high frequency components, and signals of frequency with lowΔf are solely acquired so that the sensing accuracy of the phase difference is enhanced. The first thru third waveform synthesizing circuits 42, 43, 44 are arranged so as to handle a phase adjusting circuit 1 directly by digital values. Accordingly it is possible to control the phase difference between the output signals continuously.
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