PLASMA PROCESSING METHOD

PROBLEM TO BE SOLVED: To provide a plasma processing method capable of suppressing foreign particles due to increase in the number of processed sheets of the object to be processed in plasma processing using depositional gas.SOLUTION: In a plasma processing method, etching on an object to be processed mounted on a sample stage provided in a processing chamber is conducted by generating plasma from depositional gas introduced into the processing chamber and exposing the object to be processed to the plasma in a state in which radio frequency power is applied. In the plasma processing method, the object to be processed is etched under etching conditions that a deposit film on an inner wall of the processing chamber becomes amorphous by repeating a first period during which the object to be processed is exposed to the plasma and a second period during which the object to be processed is exposed to the plasma and an etching rate for the object to be processed is lower than that in the first period.