Appeal No. 2003-0173
Application No. 09/484,473
THE INVENTION
The appellants claim a method for making a semiconductor
device wherein at least one of a titanate layer and a silicon
oxide layer is etched using an HCl/NH4F/H2O etchant. Claim 8 is
illustrative:
8. A method for farbricating a semiconductor device,
comprising the steps of:
etching at least one of a titanium material layer and a
silicon oxide layer using an etchant, wherein said titanium
material layer includes at least one material selected from the
group consisting of BaTiO3, SrTiO3, BaX Sr(1-x) TiO3, and similar
Group IIA metal titanates, and wherein the etchant includes a
mixed liquid of HC1, NH4F and H2O; and
setting a molar ratio of NH4F/HC1 in the mixed liquid,
the molar ratio being being set based on which of the at least
one of the titanium material layer and the silicon oxide layer is
to be etched.[1]
THE REFERENCES
Asselanis et al. (Asselanis) 4,759,823 Jul. 26, 1988
Moore et al. (Moore) 5,402,807 Apr. 4, 1995
Roh 5,828,129 Oct. 27, 1998
(filed Jan. 23, 1997)
1 The broadest reasonable interpretation of claim 8 in view
of the appellants’ specification, see In re Zletz, 893 F.2d 319,
321, 13 USPQ2d 1320, 1322 (Fed. Cir. 1989), is that the
semiconductor device has both a titanate layer and a silicon
oxide layer, at least one of which is etched with the
HCl/NH4F/H2O etchant.
2
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