Appeal No. 96-0294
Application No. 08/168,569
exclude light from reaching the substrate (photoresist)
beneath the mask and the defect was a transparency (hole) in
the opaque patterns. See for example column 1, lines 17
through 19 of Kellogg ("alteration of a precisely localized
site on a substrate such as a transparent defect site in a
photolithographic mask."); column 3, lines 11 through 14 of
Drozdowicz ("The metal film deposits produced by this method,
when extended over adjacent clear (missing chrome) defect
areas, make these clear areas opaque, thus effecting the
repair."); and column 6, line 11 of Harriott ("repairing a
transparent defect in said pattern").
Here, the claimed subject matter requires that the mask
being repaired be a particular type of mask, a phase-shifting
mask, which is not shown by any of the references on which the
examiner has relied and is designed to permit light through
the mask to be shifted for the purpose of causing coherent
destructive interference. The defect in appellants' mask is
not a transparency (hole) in an opaque pattern.
We have not overlooked pages 5 and 6 of the Examiner's
Answer wherein the examiner opines:
it is not all that surprising that a relatively
small area of the transmissive region which is
rendered opaque does not adversely affect
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