Plasma processing apparatus

A plasma processing apparatus comprising:

• a mounting stage on which a substrate is mounted;
• a focus ring disposed over a peripheral region of the mounting stage;
• a first magnet, magnetic body, or magnetic O-ring member provided at the bottom surface of the focus ring;
• a second magnet, magnetic body, or magnetic O-ring member provided at the upper surface of the mounting stage and arranged at a position opposite the first magnet, magnetic body, or magnetic O-ring member;
• a plurality of members that are made of a material different from the focus ring and are provided in between the focus ring and the mounting stage, whereby the plurality of members seal a heat transfer space defined by a bottom surface of the focus ring, an upper surface of the mounting stage, and the plurality of members, each member of the plurality of members being provided on opposite sides of the space;
• and
• a temperature adjustment unit configured to adjust a temperature of the focus ring, the temperature adjustment unit including a heat transfer gas supply unit, wherein
• the heat transfer supply unit is configured to supply a heat transfer gas into the heat transfer space,
• the bottom surface of the focus ring, facing opposite the mounting stage, includes a concavo-convex surface,
• the heat transfer space has a height of up to 10 μm,
• each of the plurality of members are provided in a groove formed in at least one of the bottom surface of the focus ring or the upper surface of the mounting stage,
• a first member of the plurality of members being provided along an outer circumference of the focus ring and a second member of the plurality of members being provided along an inner circumference of the focus ring, and
• each of the first member and the second member is an O-ring member.