Wafer transfer system

Apparatus for transferring a wafer from a cassette holder to an input station of a processing system, comprising:

• a single wafer transfer arm for removing a wafer form the cassette holder and for transferring the wafer between the cassette holder and the input station, said wafer transfer arm including elongated primary and secondary sections coupled together for rotation about a pivot axis, said primary section having a primary axis of rotation spaced apart form and parallel to said pivot axis, said secondary section having a wafer support pick at the opposite end from said pivot axis, said transfer arm further including linkage means for a causing said secondary section to rotate about the pivot axis at a predetermined rate greater than said primary section rotates about the primary axis;
• means for holding the cassette holder and for indexing said wafer into engagement with said wafer pick, said cassette holder being held in a vaccuum lock and said holding means including a sealed bellows mounted to expand when the vacuum lock is evacuated and to hold said cassette holder firmly in place;
• and
• means for extending and retracting said wafer transfer arm to and between the cassette holder and the input station.

A method for transferring a semiconductor wafer from a cassette holder to an input station of a processing system comprising the steps of:

• transferring the wafer from the cassette holder to a wafer location station;
• sensing an actual wafer location relative to a desired wafer location;
• determining a correction based on the difference between the actual wafer location and the desired wafer location;
• transferring said wafer from said wafer location station to said input station;
• and
• translating said wafer during the step of transferring the wafer to the input station by said correction so that said wafer is positioned at the desired location at said input station.

Apparatus for transferring a wafer from a cassette holder to an input station of a vacuum processing system, comprising:

• means for transferring the wafer to and between the cassette holder and the input station;
• a vacuum lock containing said cassette holder;
• and
• means for holding the cassette holder and for indexing said wafer into engagement with said transfer means, said holding means including a sealed bellows mounted to expand when the vacuum lock is evacuated and to retain said cassette holder firmly in place in said vacuum lock.