| 摘要 |
Apparatus and a method for contouring the surface of a thin element such as a semiconductor wafer, the apparatus including a plurality of individual reciprocatable suction cups for grasping at selected places the lower surface of the wafer. Superimposed of the wafer is a plurality of sensors for directing air against the opposite surface of the wafer and which senses, by back pressure, the distance from the terminal end of the sensor to the wafer thereby sensing the contour of the surface of the wafer. Each sensor is connected to a comparitor which responds to its associated sensor to actuate through a stepping motor and cam the individual reciprocatable suction cups to elevate or retract the same when the comparitor indicates a difference between the desired contour at that particular place on the surface and the actual contour of the wafer. |
