Plasma processing apparatus and plasma processing method

A plasma processing apparatus provided for processing a wafer which is an object to be processed using plasma by processing which includes two processing steps and a bridging step between the two processing steps, the plasma processing apparatus comprising:

• a processing chamber which is disposed in a vacuum vessel in a reduced pressure state and in which the plasma is generated;
• a specimen base which is disposed in a lower portion of the processing chamber and has an upper surface on which the wafer is placed and held;
• a first gas supply unit which supplies a processing-use gas into the processing chamber during the processing step;
• a second gas supply unit which supplies a bridging-use gas into the processing chamber during the bridging step;
• a gas switching unit for switching the supply of the processing-use gas from the first gas supply unit and the bridging use gas from the second gas supply unit to the processing chamber in transition between the two processing steps and the bridging step;
• and
• a control part which is configured to regulate a flow rate of the bridging-use gas to be supplied during the bridging step to a flow rate regarded equal to a supply amount of the processing-use gas to be supplied to the processing chamber during a succeeding step out of the two processing steps.