| 摘要 |
PROBLEM TO BE SOLVED: To detect the position of an orientation flat part of a semiconductor wafer at a high speed and with high precision to align the semiconductor wafer. SOLUTION: A semiconductor wafer W which is supported rotatably on a stage 1 is illuminated and its image is formed on an imaging element 5 via a mask 7 having a circular opening conforming with a circumference of an image. Then, an optical image formed on the imaging element 5 with high precision which is only on an outside of an edge of an orientation flat part of the semiconductor wafer W becomes an arc-shaped bright part. The position of the bright part, particularly a position of the orientation flat part from the position of the edge, is detected with non-contact, and according thereto, the stage 1 is driven so that the position of the orientation flat part comes to a target position set beforehand, and the semiconductor wafer W is rotated, so that the semiconductor wafer W can be positioned at a high speed and with high precision. |
