Abstract: A plasma processing device capable of positioning a protective member for covering the upper surface of a peripheral edge portion of a substrate, with high accuracy. A plasma processing device has, a platen on which a substrate K is placed, a gas supply device, a plasma generating device, an RF power supply unit, an annular and plate-shaped protective member configured to be capable of being placed on a peripheral portion of the platen and which covers a peripheral edge portion of the substrate K, support members supporting the protective member, and a lifting cylinder lifting up and down the platen. At least three first protrusions which are engaged with the peripheral portion of the platen are formed on a pitch circle on the lower surface of the protective member and the center of the pitch circle is co-axial with the central axis of the protective member.

Abstract: A plasma processing device capable of positioning a protective member for covering the upper surface of a peripheral edge portion of a substrate, with high accuracy. A plasma processing device has, a platen on which a substrate K is placed, a gas supply device, a plasma generating device, an RF power supply unit, an annular and plate-shaped protective member configured to be capable of being placed on a peripheral portion of the platen and which covers a peripheral edge portion of the substrate K, support members 35 supporting the protective member, and a lifting cylinder lifting up and down the platen. At least three first protrusions which are engaged with the peripheral portion of the platen are formed on a pitch circle on the lower surface of the protective member and the center of the pitch circle is co-axial with the central axis of the protective member.