| 摘要 |
PROBLEM TO BE SOLVED: To provide a wafer detector which detects the wafer flying out of a cassette at a high accuracy by a simple structure. SOLUTION: A cassette C for housing wafers W is closely contacted to the wall 10 defining an opening 11 for putting the wafer W in and out through the opening 11. To detect the existence of a wafer flying out of a housing position in the cassette C, the detector comprises transmission or reflection type optical sensors 101, 111 for irradiating the periphery of the wafer with a detecting light in a direction parallel to the main surface of the wafer and a driving mechanism having shafts 103, 113, a coupling bar, a lead screw, and a motor for scanning the optical sensors in the arranging direction of the wafer on the side of the opening 11 formed in the wall 10. This detects the wafer at a high accuracy with miniaturizing the apparatus. COPYRIGHT: (C)2006,JPO&NCIPI |
