Patent ID: 8877004

Claim:
A plasma processing apparatus comprising: a processing chamber having a top opening; a holding table that holds a processing target substrate within the processing chamber; a dielectric plate provided to close the top opening of the processing chamber and configured to face the holding table; an antenna that supplies a microwave to the dielectric plate and generates plasma on a bottom surface of the dielectric plate; and a ring-shaped protrusion member formed as a separate member from the dielectric plate and provided at a peripheral portion of the bottom surface of the dielectric plate while a gap is provided between an inner surface of a sidewall of the processing chamber and the protrusion member, the protrusion member being configured to suppress an abnormal electric discharge between the inner surface of the sidewall of the processing chamber and the protrusion member, wherein the protrusion member is made of a dielectric material an interface is formed between the dielectric plate and the protrusion member, and the protrusion member has a cylindrical part protruded downward; and a flange part extended outward from an upper end of the cylindrical part in a diametric direction and in contact with the peripheral portion of the bottom surface of the dielectric plate, and wherein the processing chamber has an upper chamber and a lower chamber, the upper chamber has a vertical part having a preset height and a non-vertical part, and a protruding length of the cylindrical part is substantially the same as the preset height so that the cylindrical part covers the vertical part of the upper chamber without covering the lower chamber.