Patent ID: 8323414

Claim:
A method of removing particles from a chamber of a plasma processing apparatus, wherein the chamber is connected to a gas exhaust port and a plasma of a processing gas is generated in the chamber to plasma process a substrate to be processed, the method comprising: positively charging the particles at a first region of the chamber by applying a first negative voltage to a first charging electrode installed in a first portion of an inner wall of the chamber; drift-transferring the positively charged particles towards a second region of the chamber by applying a second negative voltage to a second charging electrode installed in a second portion of the inner wall of the chamber; guiding the drift-transferred positively charged particles towards the gas exhaust port along the inner wall of the chamber; and discharging the guided positively charged particles from the chamber through the gas exhaust port, wherein said applying the first negative voltage attracts positive ions toward the first charging electrode and the particles are positively charged by colliding with the positive ions, wherein the second portion is closer to the gas exhaust port than the first portion and wherein the second negative voltage has an absolute value greater than the absolute value of the first negative voltage.