Plasma processing device and plasma processing method

A plasma processing method executed by a plasma processing device including:

• a junction exhaust pipe into which a plurality of exhaust flow paths for evacuating interiors of a plurality of processing chambers joins;
• a plurality of branch exhaust pipes disposed between the plurality of exhaust flow paths and the junction exhaust pipe and connecting the junction exhaust pipe to the plurality of exhaust flow paths, respectively;
• a mechanism configured to deactivate energy of hot electrons flowing through flow paths of the plurality of branch exhaust pipes;
• a gas introduction pipe configured to communicate with a flow path of the junction exhaust pipe and introduce a gas for suppressing occurrence of plasma;
• and a controller,
• preparing a substrate in at least one of the plurality of processing chambers;
• introducing the gas for suppressing occurrence of plasma from the gas introduction pipe when the number of prepared substrates is less than the number of the plurality of processing chambers;
• processing the prepared substrate with plasma of a processing gas;
• and
• evacuating the plurality of processing chambers via the plurality of exhaust flow paths, the plurality of branch exhaust pipes, and the junction exhaust pipe.