| 摘要 |
PURPOSE:To set the direction of wafers so that they are facing exactly by a method wherein a cutting off of a straight line is provided in the periphery of wafer, a plate that a hole is made on the straight line around the cutting off portion is arranged, the light is illuminated thereupon and the passing light through the holes on the plate is detected. CONSTITUTION:The wafer 5 having the straight line cutting off portion K is placed on a rotary base 1, and the center of both the wafer are the base made coincided, when the base 1 is turned by a motor 3, the cutting off portion K is crossed at a right angle with the center line O, the same quantity of light from a light source 8 enters to the detector 9a and 9b passing through holes 6a, 6b in the fixed base 7. The quantity of light is compared 10, and the motor 3 is stopped to set the wafers at desired positions. When the cutting off portion is staggered, since the light is interrupted or the detected quantity of light is different, the motor will not be stopped. In this constitution, wafers can be set in a required directions accurately. |
