Plasma processing apparatus and plasma processing method

A plasma processing apparatus, comprising:

• a processing chamber in which a sample undergoes plasma processing;
• a first high frequency power supply that supplies high frequency power for plasma generation;
• a sample stage on which the sample is loaded;
• a second high frequency power supply that supplies high frequency power to the sample stage;
• a power supply that applies voltage to the sample stage;
• and
• a control unit that controls the power supply,
• wherein a cycle of a waveform of the voltage has a positive ramp period during which the voltage rises, a negative ramp period during which the voltage falls, and a removal amount control period during which an amount of charged particles removed from the sample per unit time is controlled,
• wherein the voltage in the removal amount control period is nearly unchanged,
• wherein in a case that a value obtained by multiplying an amplitude of a desired voltage waveform by a factor of a is defined as an amplitude for the positive ramp period or an amplitude for the negative ramp period, time during the removal amount control period is time having a value obtained by multiplying a sum of time during the positive ramp period and time during the negative ramp period by a value of the a minus one, and
• the desired voltage waveform is a voltage waveform desired for removing the charged particles in case that a voltage waveform does not have the removal amount control period.