| 摘要 |
<P>PROBLEM TO BE SOLVED: To minimize the damage by quickly and reliably detecting slip-out of a wafer from a polishing head of a wafer polishing apparatus. <P>SOLUTION: A projection/image-pickup portion 11 projects a still image A onto a surface of a polishing pad 5 on a platen 2. The projection position is on the downstream side in the rotation direction of the platen and in close proximity to a polishing head 6. An image processing portion monitors a taken image. When a wafer W slips out from the polishing head to the downstream side, the image processing portion detects variations in the image caused by the slip-out of the wafer, and stops the entire system. The system, which takes a projected image and detects variations in the image, is not affected by disturbance such as external light and thus has higher detection accuracy and higher stability than a system which detects slip-out on the basis of reflectivity or color difference between a polishing pad and a platen. <P>COPYRIGHT: (C)2009,JPO&INPIT |
