Patent ID: 8496781

Claim:
A plasma processing apparatus comprising: a processing chamber disposed in a vacuum chamber, said processing chamber having a side wall of which is connected to ground, a work piece mount which mounts a work piece on an upper surface thereof; an electrode for generating discharge arranged in a position opposite to the upper surface of the work piece mount, the electrode having a plate shape and including a shower plate on a surface opposite to the work piece mount, the electrode providing an electric field inside the processing chamber for generating a plasma therein; a first high frequency power source for applying a first high frequency voltage to the electrode for generating discharge; a second high frequency power source for applying a second high frequency voltage to the work piece mount, the frequency of the second high frequency voltage being 400 kHz or more and 15 MHz or less; a low-pass filter coupled to the electrode; and a DC power source disposed between the low-pass filter and the ground, coupled to the electrode, the DC power from the DC power source being applied to the electrode via the low-pass filter; wherein the side wall of the processing chamber faces the plasma and is set to ground potential and the DC power applied from the DC power source to the electrode is controlled by a DC power source controller depending on a result of detecting the plasma potential when a periodical rise of the plasma potential is detected by a plasma potential measuring means connected to the DC power source controller, and wherein the periodical rise of the plasma potential is generated when a mean potential of the work piece is shifted to a negative potential caused by the high frequency voltage applied to the work piece mount.