Patent ID: 7557904

Claim:
A wafer holding mechanism for holding a wafer affixed to a frame with a tape, said wafer holding mechanism comprising: a suction framework; a suction unit disposed on said suction framework, said suction unit having a suction portion for transmitting a suction force; and a wafer holder disposed on said suction unit, said wafer holder being a ductless unit having an outer peripheral edge, and a holding surface for receiving the tape to hold the wafer via the tape, wherein: said wafer holder is made of quartz, boro-silicated glass, sapphire, calcium fluoride, lithium fluoride, or magnesium fluoride, said holding surface comprises a plurality of open grooves having a depth of 50 μm-100 μm and a width of 50 μm-100 μm, said grooves being open to said outer peripheral edge of said wafer holder and spaced apart by 0.1 mm-5.0 mm, and said suction portion is located at said outer peripheral edge of said wafer holder to transmit the suction force across said holding surface through said outer peripheral edge such that when the tape is placed on said holding surface, said suction portion and said wafer holder are covered and sealed by the tape to cause said wafer holder to be held at said suction unit and the wafer to be held at said holding surface by the suction force.