Front end wafer staging with wafer cassette turntables and on-the- fly wafer center finding

摘要

A front end staging method and apparatus is provided to introduce and remove a set of wafers from a vacuum processing system. The system generally comprises a support platform, one or more wafer cassette turntables disposed on the platform, a wafer handler disposed adjacent the turntables, a wafer center finding device and a filter disposed to control particles in the vicinity of the wafers. The wafer cassette turntables are rotatably mounted to the support in the preferred embodiment. The processing system may also include one or more processing chambers, where each processing chamber defines a plurality of isolated processing regions therein. The wafer center finding device may include an optical sensor system including optimal emitters aligned with optical sensors.