| CPC H01J 37/32155 (2013.01) [H01J 37/32165 (2013.01); H01J 37/32183 (2013.01); H01J 37/32174 (2013.01)] | 18 Claims |
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1. A plasma processing apparatus, comprising:
a chamber;
a substrate support in the chamber;
a radio-frequency power supply configured to provide radio-frequency power to generate plasma from a gas in the chamber;
a bias power supply configured to provide electrical bias energy to the substrate support to draw ions toward a substrate on the substrate support, the electrical bias energy having a waveform with repeated cycles each having a time length being an inverse of a bias frequency;
a memory that stores programs; and
processing circuitry, wherein
the processing circuitry is configured, with the programs stored in the memory, to control the radio-frequency power supply to perform, while the radio-frequency power is being provided and the electrical bias energy is being provided to the substrate support,
(a) using a predetermined reference time series of frequencies of the radio-frequency power in each of the repeated cycles,
(b) using, after the (a), a changed time series of frequencies of the radio-frequency power in each of the repeated cycles, and
(c) repeating the (b) to increase a degree of match of impedance between the radio-frequency power supply and a load coupled to the radio-frequency power supply based on an evaluation value indicating the degree of match, and
the changed time series used by the radio-frequency power supply in the (b) is
a time series of frequencies resulting from shifting the reference time series by a phase shift amount for each of the repeated cycles,
a time series of frequencies resulting from scaling up or down the reference time series in a frequency direction, or
a time series of frequencies resulting from scaling up or down two or more of a plurality of time zones of the reference time series in a time direction and including as many frequencies as the reference time series.
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