METHOD FOR DETECTING MISSING TRANSFERRED OBJECT HAVING MISSING PART

摘要

PROBLEM TO BE SOLVED: To provide a method for detecting an missing wafer having the missing part from wafers during transfer in a vacuum processing device inexpensively.;SOLUTION: Seventeen sets of unit sensors 43 which are a reflection type optical sensor are installed at regular intervals of the width more than that of a wafer W in a line perpendicular to the transfer direction of the wafer in an opening of the ceiling region in valve box 21 of gate valve 20 between transportation room 10 and processing room 13 through a hard glass window 25. When a unit sensor in the center of the line detects the tip of the transferred wafer, a high-speed operating part 48 starts counting at interval of millimeter second unit and accumulating the state that, in all unit sensors, a light projected from a light projecting part is reflected in a normal part of the wafer and is received in a light receiving part. When a back end of the wafer is detected, the counting is stopped. The counting number accumulated in each unit sensor is compared to that of the normal wafer. Since it is not counted in the missing part, the existence of the missing part can be recognized.;COPYRIGHT: (C)2008,JPO&INPIT