Plasma processing apparatus and plasma processing method

A method performed by a plasma processing apparatus including a first electrode on which a substrate is placeable, a second electrode disposed to face the first electrode across a predetermined gap and including a facing surface facing the first electrode, and a chamber housing the first electrode and the second electrode, the method comprising:

• placing the substrate on the first electrode;
• generating first plasma to form a film of a reaction product on the facing surface of the second electrode by supplying high-frequency power to the second electrode and supplying a first gas through gas holes formed in the facing surface into the chamber;
• generating second plasma to sputter the film of the reaction product on the facing surface of the second electrode and thereby form a film on a mask formed on the substrate by
• supplying the high-frequency power and direct-current power to the second electrode and supplying a second gas through the gas holes formed in the facing surface into the chamber, or
• supplying the high-frequency power to the second electrode, supplying high-frequency power to the first electrode, and supplying a second gas through the gas holes formed in the facing surface into the chamber, the high-frequency power supplied to the first electrode having a frequency lower than a frequency of the high-frequency power supplied to the second electrode;
• and
• etching the substrate using the mask on which the film is formed.