ERROR DETECTION AND CORRECTION DEVICE FOR POSITION OF WAFER AND ITS METHOD

摘要

PROBLEM TO BE SOLVED: To provide the error detection and correction device for the position of a wafer on a blade of a wafer carrying robot. SOLUTION: This device is a sensor placed in the vicinity of each entrance of a processing chamber to monitor the position of a wafer on a blade thereby deciding the position error of a wafer 10. This device incorporates a transparent cover 34 on a surface of a wafer processing chamber and a photosensor 60 placed on the face of the transparent cover. Furthermore, the sensor 60 directs a light through a slot 26 of the blade to sense and correct the positional error of the wafer toward a reflector 62. The position of the wafer on the blade is measured based on a distance between an end of a hole of the blade and an end of the wafer 10 and whether or not the wafer is placed correctly on the blade is decided.