Control method and plasma processing apparatus

A plasma processing apparatus comprising:

• a chamber;
• a stage provided in the chamber and that supports a substrate;
• a first power supply coupled to the stage and configured to supply a first voltage waveform having a predetermined period of cycle;
• a second power supply configured to supply a second voltage waveform having a shorter period of cycle than the predetermined period;
• and
• controller circuitry configured to control the first and second power supplies,
• wherein the controller circuitry is further configured to:
• (a) control the first power supply to supply the first voltage waveform to the stage,
• (b) control the second power supply to supply the second voltage waveform, and
• (c) detect a degree of reflection of the second voltage waveform in a first phase of a first period of the first voltage waveform, and set a frequency of the second voltage waveform based on the degree of reflection, the frequency being a period reciprocal of the second voltage waveform in the first phase of a second period following the first period of the first voltage waveform.

A control method for a plasma processing apparatus, the control method comprising:

• supplying a first voltage waveform having a predetermined period of cycle by a first power supply;
• supplying a second voltage waveform vibrating at a shorter period of cycle than the predetermined period by a second power supply;
• controlling the second power supply to detect a degree of reflection of the second voltage waveform in a first phase of a first period of the first voltage waveform;
• and
• setting a frequency based on the degree of reflection, the frequency being a period reciprocal of the second voltage waveform in the first phase of a second period following the first period of the first voltage waveform.

A non-transitory computer readable medium that stores a program for causing a computer to execute a process for a plasma processing apparatus, the process comprising:

• supplying a first voltage waveform having a predetermined period of cycle by a first power supplies;
• supplying a second voltage waveform vibrating at a shorter period of cycle than the predetermined period by a second power supply;
• controlling the second power supply to detect a degree of reflection of the second voltage waveform in a first phase of a first period of the first voltage waveform;
• and
• setting a frequency based on the degree of reflection, the frequency being a period reciprocal of the second voltage waveform in the first phase of a second period following the first period of the first voltage waveform.