Plasma processing apparatus and plasma processing method

A plasma processing apparatus comprising:

• a processing chamber configured to accommodate a substrate and perform a plasma process thereon;
• a processing gas supply unit configured to supply a processing gas into the processing chamber;
• a pair of parallel-plate-type electrodes provided within the processing chamber and including a lower electrode serving as a mounting table configured to mount the substrate thereon and an upper electrode provided above the lower electrode;
• a high frequency power supply configured to apply a high frequency power to at least one of the pair of electrodes;
• a matching unit configured to perform impedance matching of the high frequency power from the high frequency power supply, the matching unit being connected to the one of the electrodes;
• and
• a control unit configured to perform a power modulation for periodically switching the high frequency power from the high frequency power supply between a first power and a second power higher than the first power and to perform a mask control for stopping a matching operation of the matching unit for a first power application time and for a preset time after a second power application is started.