Patent ID: 8585862
Filing Date: 2013-11-19
Classification: H01J

Abstract:
1. A plasma processing device for executing plasma processing for an object to be processed which is accommodated in a processing chamber, comprising: a vacuum chamber forming the processing chamber; an electrode portion arranged in the processing chamber; a vacuum exhaust portion for exhausting gas from the processing chamber by vacuum; a gas supply portion for supplying gas which is used for generating plasma into the processing chamber; a high frequency power supply portion for generating plasma discharge in the processing chamber when a high frequency voltage is impressed upon the electrode portion; a matching device for matching impedance of a plasma discharge circuit for generating plasma discharge with impedance of the high frequency power supply portion; and a plasma discharge state monitoring means for monitoring a plasma discharge state in the processing chamber, the plasma discharge state monitoring means including: a discharge detection sensor having a plate-shaped dielectric member attached to the vacuum chamber so that one face of the plate-shaped dielectric member can be opposed to the plasma discharge generated in the processing chamber and also having a probe electrode arranged on the other face of the plate-shaped dielectric member; a plurality of wave-form detecting portions which receives a change in electric potential induced according to a change in the plasma discharge in the probe electrode and outputs a detection signal each time a change in electric potential agreeing with a predetermined condition appears, wherein one of the plurality of wave-form detecting portions further includes: a plurality of counters which respectively correspond to the plurality of wave-form detecting portions and count the detection signals outputted from the respectively corresponding plurality of wave-form detecting portions and hold the counted values; a discharge state judging portion for judging a state of plasma discharge according to the counted value of the counter obtained when the detection signal of the N-type wave-shape detecting portion is counted; and a maintenance judging portion for judging whether or not the maintenance of the vacuum chamber is necessary according to the counted value of the counter obtained when the detection signal of the V-type wave-form detecting portion is counted, wherein the N-type wave-form detecting portion detects the N-type electric potential change wave-form in a first wave-form monitoring time zone including an impression start timing of the high frequency voltage upon the electrode portion, a last wave-form monitoring time zone including an impression end timing of the high frequency voltage upon the electrode portion, and an intermediate wave-form monitoring time zone interposed between the first wave-form monitoring time zone and the last wave-form monitoring time zone, and the V-type wave-form detecting portion detects the V-shaped electric potential change wave-form in the intermediate wave-form monitoring time zone.