| 摘要 |
<p>PROBLEM TO BE SOLVED: To surely avoid deviating a wafer by providing means for detecting the force exerted on a pusher for dropping a wafer after ending an electrostatic vacuum chucking, to control the moving speed of a wafer support based on the signal from the directing means. SOLUTION: After a wafer 4 is electrostatically chucked to a dielectric film 3 by applying a DC voltage to an outer and inner electrodes 1, 2, a ground potential is given to the inner and outer electrodes 2, 1 at once by the switching of a switch so as to remove the charges stored between the dielectric film and wafer 4. When a wafer support 5 is lifted to peel the wafer 4 off from the dielectric film 3, after the discharging ends, an output signal from a load meter 6 which is means for detecting the force exerted on a pusher, is amplified by an amplifier 26 and is converted to a residual chucking force by a signal processor circuit 27, and its value is fed back to a controller 28 for controlling the rotation of a pulse motor 23 to control the lifting and lowering speeds of the wafer support 5.</p> |
