| 摘要 |
<p>PURPOSE:To position an orientation flat surface accurately by detecting the contours of the outer circumferential surface of a semiconductor wafer by a light source and an image sensor set up oppositely to the light source, comparing the contours with a reference information previously memorized and detecting the quantity of a wafer chuck to be turned. CONSTITUTION:The wafer chuck 10, a lower end section thereof is provided with a driving mechanism 11 and a nose section thereof with a wafer fixing section 12, is erected and installed rotatably, a concentrical sheet hold-down ring 13 is set up around the fixing section 12, and the peripheral section of a sheet 14 placed on the fixing section 12 is bitten into the ring 13. The light source 15 and the image sensor 16 are arranged oppositely on one end side of the sheet 14 while holding the sheet, the wafer 17 placed on the sheet 14 is turned, a controller 19 is operated when the flat 17a formed to the wafer is positioned between the light source 15 and the sensor 16, and the driving mechanism 11 is stopped. Accordingly, the flat 17a is positioned at a predetermined location.</p> |
