Plasma processing apparatus

A plasma processing apparatus comprising:

• a plurality of microwave radiators provided at a ceiling portion of a processing chamber and configured to introduce a microwave for generating a plasma of a gas into the processing chamber;
• and
• a plurality of gas supply holes formed at the ceiling portion of the processing chamber between the microwave radiators, and configured to introduce the gas into a plasma processing space,
• wherein each of the plurality of gas supply holes includes a fine hole and a cavity defined by a first surface parallel to the ceiling portion of the processing chamber, and a second surface forming an angle with respect to the first surface and connected to the ceiling portion of the plasma processing space, and the cavity is concentric with the fine hole,
• a diameter of an opening of the cavity on the plasma processing space side is 3 mm or more and is ⅛ or less of a wavelength of a surface wave of a microwave in the plasma,
• the ceiling portion of the processing chamber and at least part of the second surface of the cavity is coated with an insulating material, and
• the first surface of the cavity is not coated with an insulating material and a thickness of the insulating material coated on the second surface of the cavity is thinner than a thickness of the insulating material coated on the ceiling portion of the processing chamber,
• wherein the cavity is coated with an insulating material so that a thickness of the insulating material becomes smaller from the opening of the cavity on the plasma processing space side toward the first surface.