Plasma processing apparatus and plasma processing method

A plasma processing method, comprising:

• preparing a substrate on a substrate support inside a chamber of a plasma processing apparatus;
• performing a first plasma process on the substrate using a first processing condition including supplying a first processing gas from a gas supplier into the chamber during a first processing period;
• and
• performing a second plasma process on the substrate using a second processing condition including supplying a second processing gas from the gas supplier into the chamber during a second processing period,
• wherein during each of the first processing period and the second processing period, a source radio-frequency power for plasma generation is supplied, and electric bias is supplied from a bias power supply to the substrate support,
• wherein during the first processing period, a plurality of frequencies included in a first frequency set determined to reduce a degree of reflection of the source radio-frequency power from a load are used as the source frequency of the source radio-frequency power for each of a plurality of phase periods in a waveform period of the electric bias, and
• wherein during the second processing period, a plurality of frequencies included in a second frequency set different from the first frequency set and determined to reduce a degree of reflection of the source radio-frequency power from the load are used as the source frequency for each of the plurality of phase periods in the waveform period of the electric bias.