Plasma processor and plasma processing method

A plasma processing apparatus comprising:

• a processing chamber configured to accommodate a substrate to be processed and performing a plasma processing thereon;
• a susceptor installed inside the processing chamber to mount the substrate thereon, the susceptor serving as an electrode;
• a first path formed inside the susceptor to circulate a coolant therethrough, the first path including
• a coolant inlet line,
• a coolant exhaust line extending vertically to exhaust the coolant, and
• a coolant circulating line connected to the coolant inlet line and the coolant exhaust line, the coolant inlet line introducing the coolant into the coolant circulating line;
• and
• a second path, formed inside the susceptor, including
• a gas inlet portion configured to supply a cooling gas from a bottom of the susceptor,
• a gas storage being connected to the gas inlet portion and being configured to store the cooling gas,
• fine grooves formed on a mounting surface of the susceptor, and
• gas supply fine holes to supply the cooling gas from the gas storage to the fine grooves,
• wherein a temperature of the susceptor is controlled by circulating the coolant through the coolant circulating line and a temperature of the substrate to be processed is controlled by supplying the cooling gas from the gas storage to a backside of the substrate mounted on the susceptor through the gas supply fine holes, and the gas storage is formed under the coolant circulating line, and
• wherein dimensions of the gas storage are different from those of the gas inlet portion and the gas supply fine holes.