Dechuck control method and plasma processing apparatus

A dechuck control method for dechucking a processing object from an electrostatic chuck that electrostatically attracts the processing object and includes a chuck electrode, the method comprising the steps of:

• performing a discharge process after a plasma process by introducing an inert gas into a processing chamber and maintaining a pressure within the processing chamber at a first pressure;
• monitoring at least one of a pressure of a heat transmitting gas supplied to a rear face of the processing object that is placed on the electrostatic chuck and a leakage flow rate of the heat transmitting gas leaking from the rear face of the processing object;
• obtaining an amount of residual electric charge of a surface of the electrostatic chuck and a polarity of the residual electric charge based on a monitoring result of the monitoring step, obtaining a voltage for supplying to the chuck electrode an electric charge that is of the same amount as the residual electric charge and of the opposite polarity with respect to the polarity of the residual electric charge, and applying the obtained voltage to the chuck electrode;
• evacuating the inert gas within the processing chamber while applying the obtained voltage to the chuck electrode and reducing the pressure within the processing chamber to a second pressure;
• and
• turning off the obtained voltage applied
• to the electrostatic chuck and dechucking the processing object from the electrostatic chuck using a support pin.