| 摘要 |
<p>PROBLEM TO BE SOLVED: To protect the rear surface of a wafer placed on a wafer stage against damage and to prevent particles from being generated by damage that occurs in the wafer. SOLUTION: Three wafer support pins 4 which are set movable in a vertical direction are provided upright on the wafer suction surface 2a of a wafer stage, where the wafer support pins 4 can be optionally controlled in a descending rate. A control means 5 which controls the descending rate of the wafer support pins 4 is provided to the wafer support pins 4. The control means 5 makes the wafer support pins 4 descend to a prescribed position (d) on the wafer suction surface 2a and stop for a time, and after the temperature of the wafer W becomes nearly equal to that of the wafer suction surface 2a by radiation from the wafer suction surface 2a, the wafer support pins 4 are made to descend again so as to make the upper ends of the wafer support pins 4 located below the wafer suction surface 2a, by which the wafer W is made to descend and placed on the wafer suction surface 2a.</p> |
