Reduced edge contact wafer handling system and method of retrofitting and using same

Abstract

A wafer handling system and a method of retrofitting the system to an existing wafer handling apparatus are provided that make possible a method of handling wafers by contacting only a narrow area of not more than two millimeters wide adjacent the edge of the wafer, which is particularly useful for backside deposition where device side contact defines an area of exclusion that renders the wafer unusable in that area. The system provides a chuck on a wafer transfer arm that holds a wafer by gravity on a segmented, upwardly facing annular surface. A compatible annular surface is provided on an aligning station chuck so that wafers can be transferred by contact only with the exclusion area of the wafer surface. A load arm has two similarly compatible chucks further provided with pneumatically actuated grippers to allow the wafer to be loaded into a vertical processing apparatus. The wafer chucks are retrofitted into a processing apparatus in place of vacuum chucks and the vacuum lines that were provided to activate them are used for wafer detection. The electrical signals that were provided for vacuum chuck commands are utilized to actuate the grippers on the transfer arm so that no control software and little hardware need be altered for the retrofit.