Appeal No. 95-0589
Application 07/873,150
1. A method of manufacturing a phase-shifting mask having a
light shielding portion, a light permeation portion and a phase-
shifting portion on a transparent substrate, wherein the method
comprises:
forming a negative resist layer over the entire surface of
the transparent substrate formed with a light shielding material
pattern,
applying exposure through the rearface of the transparent
substrate and development to leave the negative resist layer on
the light permeation portion,
etching back said negative resist layer to form a sub-space
between the negative resist layer and the light shielding portion
and using said negative resist layer as a phase-shifting portion.
The examiner relies upon the following reference as evidence
of obviousness:
Okamoto 5,045,417 Sept. 3, 1991
Appellant's claimed invention is directed to a method of
making a phase-shifting mask. The mask comprises a light
shielding portion and a light permeation portion on a transparent
substrate. According to appellant, a "basic feature" of the
claimed photolithographic method is exposing the resist through
the rear surface of the substrate, wherein light shielding
portions on the substrate are used as the exposure mask (page 7
of appellant's principal Brief, last sentence).
Appealed claims 1-11 stand rejected under 35 U.S.C. § 103 as
being unpatentable over Okamoto.
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