Plasma processing apparatus and plasma processing method

A plasma processing apparatus comprising:

• a plasma processing chamber;
• a substrate support disposed in the plasma processing chamber and including a lower electrode;
• a cover disposed on the plasma processing chamber and having an internal space;
• a showerhead assembly disposed above the substrate support and including a conductive member and an upper electrode, the conductive member having a coolant passage and an upper surface exposed to the internal space of the cover;
• a plasma generator configured to generate a plasma in a space between the substrate support and the showerhead assembly;
• a gas supply configured to supply a gas into the internal space of the cover, the gas comprising an inert gas or dry air;
• an exhaust device configured to exhaust a gas in the internal space of the cover;
• a valve disposed between the exhaust device and the internal space of the cover;
• a pressure gauge configured to measure a pressure in the internal space of the cover;
• and
• a controller configured to control the valve based on measurements of the pressure gauge.

A plasma processing apparatus comprising:

• a plasma processing chamber;
• a substrate support disposed in the plasma processing chamber and including a lower electrode;
• a cover disposed on the plasma processing chamber and having an internal space;
• a showerhead assembly disposed above the substrate support and including a conductive member and an upper electrode, the conductive member having a coolant passage and an upper surface exposed to the internal space of the cover;
• a plasma generator configured to generate a plasma in a space between the substrate support and the showerhead assembly;
• and
• a gas supply configured to supply a gas into the internal space of the cover, the gas comprising an inert gas or dry air.