Plasma processing apparatus

A plasma processing apparatus, comprising:

• a chamber in which an inner part with a protective coating thereon is disposed on an inner wall of the chamber;
• a sample stage disposed in the chamber, the sample stage including a wafer attracting electrode on a sample placing surface thereof, the electrode being insulated from the sample stage by an insulating layer;
• a gas introducing unit including a dielectric vacuum window including a gas outlet for introducing processing gas into a central section of the chamber;
• a bias applying high-frequency wave power supply for applying a high-frequency bias voltage to the sample stage;
• a plasma generating high-frequency wave power source including a loop-shaped antenna on the vacuum window in an upper section of the chamber applying a high-frequency electromagnetic field via the antenna to the chamber to supply high-frequency wave energy to the processing gas introduced into the chamber to thereby generate plasma;
• a wafer attracting power source for applying a direct-current voltage to the wafer attracting electrode to attract an wafer, whereby a plasma processing is conducted for the sample placed on the sample stage using the plasma thus generated;
• a wafer attracting current monitor for monitoring a current supplied from the wafer attracting power source;
• an impedance monitor provided on a plasma generating side for monitoring an impedance of the plasma viewed from the plasma generating high-frequency power source;
• an impedance monitor provided on a bias applying side for monitoring an impedance of the plasma viewed from the bias applying high-frequency power supply;
• and
• a control device for determining presence of insulation breakdown in the protective coating on the inner part when the monitor value of the wafer attracting current monitor abruptly increases pulse-wise and no variation appears in the monitor value of the impedance monitor provided on the plasma generating side and the monitor value of the impedance monitor provided on the bias applying side.