Patent ID: 8389411

Claim:
A method of managing a substrate when a to-be-processed substrate is held by an electrostatic chuck, the electrostatic chuck comprising: a chuck main body having a plurality of electrodes; a chuck plate of a dielectric material, the chuck plate having a rib portion with which a peripheral edge portion of the to-be-processed substrate is capable of coming into surface contact, and a plurality of supporting portions which are vertically disposed at a predetermined distance from one another in an inner space enclosed by the rib portion; and a gas introduction means for introducing a predetermined gas into the inner space; wherein, when the substrate is held by the electrostatic chuck which is arranged to attract the substrate by applying a predetermined voltage between the electrodes and to form a gas atmosphere by supplying a predetermined gas into the inner space, a substrate state is managed to be free from incurring damages to the substrate, the method comprising: monitoring a current value by causing an AC current to flow through a capacitance of the chuck plate by means of an AC power supply; monitoring a gas flow amount by causing the gas to flow from the gas introduction means; and managing the substrate state based on a variation in at least one of the current value and the gas flow amount by contacting the surface with the rib portion over the circumference of the substrate.