| 摘要 |
<p>PURPOSE: To eliminate rapid change of nitrogen gas flow rate at the time of chucking and unchucking a wafer, prevent contamination, and convey a wafer in the state that the surface of the wafer is kept clean. CONSTITUTION: The Bernoulli chuck consists of the following; a pair of disks of an upper part 15 and a lower part 16 which form nitrogen gas flowing-out paths 17a-17d, nitrogen gas flowing-out ports 17e-17h which are formed on the lower part disk 16 and continuously connected to the nitrogen gas flowing- out paths 17a-17d, and a rotary plate 20 which is arranged so as to face the lower part disk 16, forms aperture parts 21a, 21c corresponding to the gas flowing-out ports 17e-17h and is rotatable in a restricted angle range. Gas flow rate is changed by changing the overlapping area of the nitrogen gas flowing-out ports 17e-17h and the aperture parts 21a, 21c while making nitrogen gas flow at a constant rate in the case of chucking and unchucking a wafer, and the chucking and unchucking of the wafer is performed.</p> |
