Ex Parte Prall

Board of Patent Appeals and Interferences

Oct 22, 2003

09288932 (B.P.A.I. Oct. 22, 2003)

1
The opinion in support of the decision being entered today was
not written for publication and is not binding precedent of the
Board.
Paper No. 24
UNITED STATES PATENT AND TRADEMARK OFFICE
__________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________
Ex parte KIRK D. PRALL
__________
Appeal No. 2003-1556
Application 09/288,932
___________
ON BRIEF
___________
Before OWENS, WALTZ and KRATZ, Administrative Patent Judges.
OWENS, Administrative Patent Judge.
DECISION ON APPEAL
This appeal is from the final rejection of claims 1-12,
which are all of the claims remaining in the application.
THE INVENTION
The appellant claims a semiconductor structure which has a
specified removable spacer layer and is useful for forming a
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Application 09/288,932

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semiconductor device having a sublithographic buried contact.
Claim 1 is illustrative:
1. A semiconductor structure for formation of a
semiconductor device having a sublithographic buried contact
therein, the assembly comprising:
a plurality of transistor gate structures and word lines
adjacent a buried contact area on a substrate, the word lines
lying in substantially parallel relation to one another and
defining a first gap between word lines peripheral to the buried
contact and a second gap between word lines atop the buried
contact, which second gap is wider than the first gap;
an insulator layer deposited over and adjacent the gate
structures, word lines, buried contact area, and substrate; and
a removable spacer layer deposited over the insulator layer
substantially filling the first gap, partially filling the second
gap, and defining a sublithographic dimension between removable
spacer walls formed over the buried contact area, the removable
spacer walls being formed by the removable spacer layer adjacent
the plurality of gate structures, wherein the removable spacer
layer provides an enhanced etching selectivity in relation to the
insulator layer and is adapted to be completely removed when
isotropically etched.
THE REFERENCES
Cathey et al. (Cathey) 5,069,747 Dec. 3, 1991
Kobayashi 5,422,315 Jun. 6, 1995
THE REJECTION
Claims 1-12 stand rejected under 35 U.S.C. § 103 as being
unpatentable over Kobayashi in view of Cathey.
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Application 09/288,932

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OPINION
We reverse the aforementioned rejection. We need to address
only the independent claims, i.e., claims 1 and 6.
The appellant’s claims 1 and 6 both require a removable
spacer layer which is over an insulator layer, has an enhanced
etching selectivity in relation to the insulator layer, and is
adapted to be completely removed when isotropically etched.
The examiner argues, in reliance upon In re Hutchinson,
154 F.2d 135, 69 USPQ 138 (CCPA 1946), that “adapted to” does not
constitute a limitation in any patentable sense (answer, page 7).
In Hutchinson the court did not consider the preamble phrase
“adapted for use in the fabrication of a metal template or the
like” to “constitute a limitation in any patentable sense”. See
Hutchinson, 154 F.2d at 138, 69 USPQ at 141. In the present
case, in contrast, “adapted to” imposes a capability requirement
on the removable spacer, i.e., it must be completely removable
when isotropically etched.
The examiner argues that the appellant’s “isotropically
etched” limitation is a method limitation in a product-by-process
claim and, therefore, is given no patentable weight in
determining the patentability of the final device structure
(answer, pages 4-5 and 7). The appellant’s semiconductor
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Application 09/288,932

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structure as claimed, however, includes a removable spacer layer
which is “adapted to be completely removed when isotropically
etched.” Hence, the ability of the removable spacer layer to be
completely removed when isotropically etched is a capability
requirement of part of the claimed semiconductor structure.
The examiner considers Kobayashi’s second insulator
layer (26) to correspond to the appellant’s removable spacer
layer (answer, pages 3-4). The examiner argues that one of
ordinary skill in the art would have been led to replace
Kobayashi’s second insulator layer with Cathey’s removable spacer
layer (21) (col. 4, line 63 - col. 5, line 2; col. 5, lines 9-13)
so that the layer could be removed without significantly etching
the first insulator layer (24) and enlarging the size of a buried
contact opening between adjacent word lines (answer, page 4).
Kobayashi, however, does not indicate that any of the first
insulator layer is removed when the desired portion of the second
insulator layer is etched away. In fact, Kobayashi shows that
after the second insulator layer has been etched, the first
insulator layer remains almost completely covered by the second
insulator layer (figure 2D). Moreover, Kobayashi leaves a
portion of the second insulator layer in place to surround or
confine the contact hole (col. 4, lines 5-14; figure 2G). For
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Application 09/288,932

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these reasons, Kobayashi would not have indicated to one of
ordinary skill in the art that the contact hole is enlarged due
to removal of the first insulator layer.
The examiner, therefore, has not established that the
applied references would have led one of ordinary skill in the
art to replace Kobayashi’s second insulator layer with Cathey’s
removable spacer layer. Accordingly, we reverse the examiner’s
rejection.
DECISION
The rejection of claims 1-12 under 35 U.S.C. § 103 over
Kobayashi in view of Cathey is reversed.
REVERSED
)
TERRY J. OWENS )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
THOMAS A. WALTZ )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
PETER F. KRATZ )
Administrative Patent Judge )
TJO/ki
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Application 09/288,932

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Edgar R. Cataxinos
Trask, Britt & Rossa
P.O. Box 2550
Salt Lake City, UT 84110