Chuck-Matching Alignment System
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-03
The alignment of multiple chucks in an exposure tool is accomplished using the optical system of the exposure tool. A first wafer chuck is mechanically registered; a master wafer is placed on the chuck's pedestal; a mask is placed within the tool; and the pedestal is positioned so as to align the wafer to the mask as viewed through the tool optics. This process is repeated for any additional chucks used in the exposure tool. The alignment mechanism used is contained entirely within the chuck itself without any need for an external jig or fixture for proper alignment. As shown in the figure, chuck 1 has structure 2 and pedestal 3 mounted thereon. Structure 2 may be moved with respect to chuck 1 and then locked. This is unlike conventional chuck assemblies wherein pedestal 3 is mounted directly on chuck 1.