Patent ID: 8445988

Claim:
An apparatus for plasma processing comprising: a substrate supporting member for supporting a substrate, installed in a reaction room of a processing chamber; a RF generator for supplying a RF voltage to the substrate supporting member so as to form plasma in the reaction room; and a matching device for matching impedance of the RF voltage to be supplied to the substrate supporting member from the RF generator, wherein the matching device comprises: a matching unit for matching the impedance of RF voltage; and an inductive RF detecting unit including a first filter connected to a node between the matching unit and the substrate supporting member, and an inductive RF detecting circuit connected to an output terminal of the first filter, wherein the first filter removes noise frequency elements except a waveform of the RF voltage from a waveform of an inductive RF voltage induced to the substrate supporting member, and wherein the inductive RF detecting circuit is configured to detect the inductive RF detecting voltage from the waveform of the inductive RF voltage from which the noise frequency elements are removed by the first filter, and supplies the detected inductive RF detecting voltage to the RF generator so as to control the RF voltage.