SYSTEM FOR DETECTING WAFER OF STEPPER LOADER

摘要

PURPOSE: A wafer detection system of a stepper loader is provided to exactly detect a wafer mounted in a carrier irrespective of the influence of a robot arm and a driving motor. CONSTITUTION: The wafer detection system comprises a wafer detection sensor(30), a digital logic circuit generator(34) and a controller(32). The wafer detection sensor(30) includes a pair of light emitting and light receiving devices and detects a wafer(W) in a carrier(K) by transmitting and receiving IRs(Infrared Rays). If an analog signal inputs from the wafer detection sensor(30), the digital logic circuit generator(34) generates a clock signal for confirming whether the wafer exists based on stored logic data. The controller(32) determines whether the wafer(W) exists in the carrier by calculating the clock signal.