Patent ID: 7670437
Filing Date: 2010-03-02
Classification: H01L

Abstract:
1. A system for aligning a mask to a substrate comprising: a removable alignment fixture configured to temporarily hold said mask and said substrate in fixed positions relative to each other, said alignment fixture having a circular top ring and a circular bottom ring; a vacuum chuck configured to hold a bottom surface of said substrate to a top surface of said vacuum chuck, said vacuum chuck protruding through an opening in a top plate and an opening in said alignment fixture, said vacuum chuck fixedly mounted on a stage assembly, said stage assembly moveable in first and second directions and rotatable about an axis relative to said top plate, said stage assembly and said top plate mounted to a base; three or more clamping mechanisms configured to temporarily affix said alignment fixture containing said mask and said substrate to said top plate by engaging a top surface of said top ring, said three or more clamping mechanisms mounted to said top plate; a computer programmed to control said three or more clamping mechanisms and vacuum applied to said vacuum chuck so as to generate a uniform force around a perimeter of said alignment fixture while said alignment fixture is temporarily affixed to said top plate; a pattern recognition system comprising a camera, pattern recognition software and said computer, said pattern recognition system configured to align said mask to said substrate, said pattern recognition system configured to control movement of said stage assembly in said first and second directions and rotation about said axis; and three or more clipping mechanisms configured to temporarily fasten top and bottom rings of said alignment fixture together with clips that engage retaining posts in said top ring, said three or more clipping mechanisms mounted to said top plate, clips of said three or more clipping mechanisms removable with said alignment fixture.