Workpiece holding mechanism

A holding mechanism of an object to be processed mounted on a plasma processing apparatus which applies high-frequency power from a high-frequency power source to one of two electrodes disposed opposite to each other to generate plasma discharge, thereby subjecting the object to be processed to a plasma processing, the mechanism comprising:

• an electrostatic chuck which is attached to the electrode connected to the high-frequency power source and which electrostatically adsorbs the object to be processed;
• a high-voltage power source which applies a direct-current voltage to the electrode and which generates an electrostatic adsorption force in the electrostatic chuck;
• a detection circuit to detect a direct-current component generated on the electrode, when the high-frequency power is applied to the electrode to subject the object to be processed to the predetermined plasma processing;
• and
• a changeover switch which can electrically disconnect the detection circuit from the electrode at a processing time of the object to be processed and which can electrically connect the detection circuit to the electrode at a detection time of the direct-current component or at a non-processing time of the object to be processed.