Patent ID: 7288492

Claim:
A fixture for holding a wafer and an evaporative mask comprising: a bottom ring having a inner periphery and an outer periphery, said bottom ring having a raised inner lip formed along said inner periphery and a raised outer lip formed along said outer periphery, the height of said inner lip above a surface of said bottom ring being greater than a height of said outer lip above said surface of said bottom ring; a shim having a inner and an outer periphery, the outer periphery of said shim fitting inside and in proximity to said outer lip of said bottom ring, a bottom surface of said shim proximate to said inner periphery of said shim contacting an upper surface of said inner lip of said bottom ring; a top ring having an inner periphery and an outer periphery, said top ring having a lower raised lip formed along said inner periphery of said bottom ring and extending below a bottom surface of said top ring; and said bottom ring and said top ring adapted to press a bottom surface of said wafer against an upper surface of said shim and to press a top surface of said wafer against a bottom surface of said evaporative mask and to press a top surface of said evaporative mask proximate to said periphery of said evaporative mask against a lower surface of said lower raised lip of said top ring.