| 摘要 |
<p>PURPOSE:To detect the position of an orientation flat of a wafer easily by rotating the wafer having the orientation flat on a rotary axis. CONSTITUTION:While the circle center of a glass wafer 1 which is conveyed is agreed with the rotary center of a rotary stage 2 by an apparatus not shown in the figure, the glass wafer is vacuum-adsorbed to the rotary stage 2 and kept horizontally and in freely rotatable condition. A microcomputer 11 rotates and drives a motor 12 by a constant angle through a motor driving drive 13. Consequently, the glass wafer 1 held by the rotary stage 2 is also rotated by a constant angle. Address counter 15 is added with every rotation by a constant angle. Signals from a photoreceptor device 6 with this timing are amplified by a pre-amplifier 7, converted into digital signals by an A/D converter 8, and recorded on a latch 9. The recorded data is written down in a memory 10 and processed by the microcomputer 11. In this case, at the time the quantity of the photoreception is the maximum, the rotary angle determines the position of the orientation flat.</p> |
