Plasma processing device

A plasma processing device for executing plasma processing for an object to be processed that 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 exhausting gas from the processing chamber by vacuum;
• a gas supply portion supplying gas used for generating plasma into the processing chamber;
• a high frequency power supply portion generating plasma discharge in the processing chamber when a high frequency voltage is impressed upon the electrode portion;
• a matching device matching impedance of a plasma discharge circuit for generating plasma discharge with impedance of the high frequency power supply portion;
• a plasma discharge state monitoring unit monitoring a plasma discharge state in the processing chamber, the plasma discharge state monitoring unit 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 first wave-form detecting portion receiving a change in electric potential induced according to a change in the plasma discharge in the probe electrode and detecting an electric potential change wave-form of a specific pattern generated according to abnormal discharge;
• and
• a second wave-form detecting portion receiving the change in electric potential and detecting an electric potential wave-form of the specific pattern caused by leak discharge;
• and
• a first counting portion counting the number of times of the detection of the electric potential change wave-form made by the first wave-form detecting portion so as to hold an counted value;
• a discharge state judging portion judging a state of the plasma discharge according to the counted value of the first counting portion;
• a second counting portion counting the number of times of the detection of the electric potential change wave-form made by the second wave-form detecting portion so as to hold an counted value;
• and
• a maintenance judging portion judging whether or not the maintenance of the vacuum chamber is needed according to the counted value of the second counting portion.