Plasma processing method and plasma processing apparatus

A plasma processing apparatus comprising:

• a process chamber;
• a mounting table provided in the process chamber;
• an electrode provided to face the mounting table;
• and
• a processor that is configured to:
• apply a pulse wave of high frequency electric power for plasma generation and a pulse wave of high frequency electric power for bias whose frequency is lower than that of the high frequency electric power for plasma generation on the mounting table, and
• control the pulse wave of the high frequency electric power for plasma generation and the pulse wave of the high frequency electric power for bias such that a predetermined phase difference is generated between the pulse wave of the high frequency electric power for plasma generation and the pulse wave of the high frequency electric power for bias, and a duty ratio of the high frequency electric power for plasma generation becomes greater than or equal to a duty ratio of the high frequency electric power for bias,
• wherein the processor is further configured to:
• set the duty ratio of the high frequency electric power for plasma generation greater than the duty ratio of the high frequency electric power for bias, and
• selectively increase an etching rate at a middle portion of the substrate between a center portion and an edge portion of the substrate.