ELECTROSTATIC DECHUCKING METHOD AND APPARATUS FOR DIELECTRIC WORKPIECE IN VACUUM PROCESSOR

摘要

PROBLEM TO BE SOLVED: To provide a dechucking method of an electrostatically chucked workpiece by preventing rupture and cracks. SOLUTION: A glass workpiece 32 is dechucked from a monopolar electrostatic chuck by gradually reducing the chucking voltage during processing while maintaining the voltage high enough to clamp the workpiece in a plasma processing chamber. The chucking voltage during processing is controlled in response to flow rate of a heat transfer fluid flowing to the chuck to maintain the chucking force and the flow rate approximately constant. A reverse polarity voltage applied to the chuck at the end of processing assists in dechucking. The workpiece temperature is maintained at a high value at the end of processing to assisting in dechucking. A peak current flowing through the chuck during workpiece lifting from the chuck controls the amplitude and/or duration of the reverse polarity voltage during the next dechucking operation. An inert plasma in the chamber removes a residual charge from the workpiece after workpiece lifting from the chuck. COPYRIGHT: (C)2010,JPO&INPIT