APPARATUS FOR DETECTING INSERTION STATE OF WAFER INTO CASSETTE IN HANDLER

摘要

PURPOSE: An apparatus for detecting an insertion state of a wafer into a cassette in a handler is provided to determine an inserting state of a wafer by detecting the wafer optically. CONSTITUTION: A light beam source(14) is used for emitting a beam to a loading position of a wafer(12) between slots(10) formed in a cassette. A photo detector(16) is used for detecting the beam emitted from the light beam source(14). The photo detector(16) converts the detected signal to a voltage of a predetermined level and applies the converted voltage to a determination portion(18). The determination portion(18) receives a predetermined pulse signal from a timer(20). The light beam source(14) and the photo detector(16) are formed at a left side and a right side or a front side and a rear side of an inserting direction of the cassette. The determination portion(18) outputs a result signal to a driving portion(22) and an alarm portion(24).