Patent ID: 6546307
Filing Date: 2003-04-08
Classification: H01L

Abstract:
Apparatus for controlling the operation of a semiconductor wafer transfer robot of the type including movable robotic arm means, a wafer blade for holding a wafer, and motor means for driving said arm means, comprising:means for sensing proper positioning of said wafer and said blade and producing an error signal when said at least one of said wafer and said blade is not properly positioned, said sensing means including (1) a pair of lasers positioned to respectively produce a pair of laser beams passing across and closely spaced from the surface of said blade, and (2) a pair of laser beam sensors for respectively sensing said beams, and each producing an output signal when a corresponding one of said beams is sensed, wherein at least one of said beams is blocked by said wafer or said blade so as not to be received by the corresponding sensor when one of said blade or said wafer is not properly positioned, one of said pairs of said lasers and said sensors being carried on and movable with said arm, and the other of said pair of lasers and said sensors being stationarily mounted; and, control means for controlling said motor means and responsive to said error signal for stopping the movement of said robotic arm means when said one of said wafer and said blade is not properly positioned.