| 摘要 |
<p>PURPOSE:To improve the certainty of handling and to improve the availability and the throughput of a device by repeating the holding operation by the required times until the adequacy is achieved when the holding is not adequate when a chucking plate is lifted up and a substrate is held. CONSTITUTION:A chucking head 14 is lifted up from a position, where a wafer 12 can be held, by DELTAZ1. The state, wherein a chucking plate 17 and the wafer 12 are almost in contact, is obtained, and the wafer 12 is sucked with vacuum. The presence or absence of the wafer 12 is detected by the detection of the pressure of the chucking plate 17 at this time. When it is judged to be present, the wafer is lifted up by DELTAZ2, and the non-contact state with the wafer cassette is obtained. On the contrary, when it is judged to be absent, the chucking head 14 is lowered by DELTAZ1. The number of the retrying times is counted. When the number of the retrying times is less than a preset times, the head is lifted up by DELTAZ1 again. The state, wherein the chucking plate 17 and the wafer 12 are almost in contact, is obtained, and the wafer 12 is detected.</p> |
