An alignment apparatus which obtains an amount of correction for centering a semiconductor wafer from four points of a wafer edge detected by noncontact proprioceptors in a wafer delivery position P1 where the semiconductor wafer is passed to a wafer carrying unit from a wafer carrying robot and centers...http://www.google.de/patents/US6549825?utm_source=gb-gplus-sharePatent US6549825 - Alignment apparatus
