| 摘要 |
PURPOSE:To position with good accuracy in non-contact with wafers by a method wherein the amount of displacement from the reference position of a wafer is obtained on the basis of outer image information detected by an image detector, and wafer positioning is performed on the basis of this amount of displacement. CONSTITUTION:A camera 3 takes a picture of a wafer 1 via pickup lens 2. The image is converted into digital signals by an analog-digital converter 4 and stored in a memory 5. A central processing unit 6 determines the amount of displacement from the reference position of the wafer and the angle of the orientation flat part on the basis of the outer image information of the wafer taken a picture by the camera 3. A stage control circuit 7 performs wafer alignment on the basis of these amounts of displacement. |
