WAFER TEACHING APPARATUS FOR OVERLAY EQUIPMENT AND METHOD THEREOF

摘要

An apparatus and a method for teaching a wafer for overlay equipment are provided to check distance difference between an accurate loading position of the wafer and a rear position of the wafer. A cassette receiving plural wafers is loaded on a cassette loader(20), and the wafer is transferred from the cassette of the cassette loader by a transfer robot(30) one by one. A teaching sensor(40) is provided on a blade(32) of the transfer robot to teach a loading state of the wafer in the cassette. A teaching controller compares wafer information input from the teaching sensor with preset information to compensate automatically a teaching value. A robot controller controls the transfer robot according to the teaching compensation value.