Ex parte SATO

Board of Patent Appeals and Interferences

May 10, 2001

08283253 (B.P.A.I. May. 10, 2001)

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not written for publication and is not binding precedent of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. 39
UNITED STATES PATENT AND TRADEMARK OFFICE
__________________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
_______________
Ex parte JUNICHI SATO
_______________
Appeal No. 1998-2669
Application 08/283,253
_______________
HEARD: April 24, 2001
_______________
This is a decision on an appeal from the final
rejection of claims 8-11, 13-15, and 17-28, which are all of
the claims remaining in the application.
The subject matter on appeal relates to a method of
manufacturing a semiconductor device which includes the steps
of forming a first film of pure metal by chemical vapor
Appeal No. 1998-1216
Application 08/356,194
2
deposition and without exposing the first film to air
successively forming a second film by chemical vapor
deposition on the first film,
wherein the second film is a metal oxynitride and the metal of
this compound constitutes the metal used to form the first
film. Further details of this appealed subject matter are set
forth in representative independent claim 8, which reads as
follows:
8. A method of manufacturing a semiconductor device
comprising the steps of providing a semiconductor substrate
having a patterned insulating layer formed on a surface
thereof, the insulating layer being patterned to form at least
one contact hole defining side walls of said insulating layer
and an exposed portion of the surface of said semiconductor
substrate; forming a first film by a first chemical vapor
deposition to cover the patterned insulating layer, the side
walls and the exposed portion, the first film being a pure
metal selected from a group consisting of titanium, tungsten,
molybdenum, hafnium, and zirconium; without exposing the first
film to air, successively forming a second film by a second
chemical vapor deposition on the first film, said second film
being a metal oxynitride and the metal of the compound being
the metal used to form the first film; and then forming a
tungsten film on the second film to fill each contact hole
with the tungsten film, said first and second chemical vapor
depositions being performed using a gas consisting of a
halogen and said metal.
Appeal No. 1998-1216
Application 08/356,194
3
The prior art set forth below is relied upon by the
examiner as evidence of obviousness:
Sarin 4,943,450 July 24, 1990
Kawakami 5,099,790 Mar. 31, 1992
Sandhu et al. (Sandhu) 5,173,327 Dec. 22, 1992
Hirose et al. (Hirose) 5,203,959 Apr. 20, 1993
Asahina 5,342,806 Aug. 30, 1994
Kumar et al. (Kumar), "Growth and Properties of TiN and TiO Nx y
Diffusion Barriers in Silicon on Sapphire Integrated
Circuits," Thin Solid Films, 287-301 (1987).
The admitted prior art described by the appellant on pages 1-3
of the subject specification.
The following rejections under 35 U.S.C. § 103 are
before us on this appeal:
Claims 8, 9, 13, 14, 17-19, 21, 23, and 24 stand
rejected over the admitted prior art in view of Kumar or
Asahina and further in view of Hirose.
Claims 11 and 15 stand rejected over the admitted
prior art in view of Kumar and further in view of Hirose and
further in view of Sandhu.
Claim 10 stands rejected over the admitted prior art
in view of Kumar and further in view of Hirose and further in
view of Sarin.
Appeal No. 1998-1216
Application 08/356,194
4
Claims 20, 22, 25, and 26 stand rejected over the
admitted prior art in view of Kumar or Asahina and further in
view of Hirose and further in view of Kawakami.
Finally, claims 27 and 28 stand rejected over the
prior art listed immediately above and further in view of
Sandhu.
We refer to the brief and reply brief and to the
answer for a complete exposition of the opposing viewpoints
expressed by the appellant and by the examiner concerning the
above-noted rejections.
OPINION
We will not sustain any of the rejections advanced
by the examiner on this appeal.
All of the appealed claims distinguish over the
admitted prior art by requiring that the first film be formed
by chemical vapor deposition and without exposing the first
film to air successively forming a second film by chemical
Appeal No. 1998-1216
Application 08/356,194
5
vapor deposition on the first film. In contrast, the admitted
prior art applies the first (i.e., the Ti) film by sputtering
and then a second (i.e., the TiON) film according to a
chemical vapor deposition process. With respect to each of
the rejections before us, it is the examiner's position that
it would have been obvious for one
skilled in the art at the time the
invention was made to have
substituted Hirose et al's
(5,203,959) ECR-CVD thin film
depositing method for the sputtering
thin film method of the [admitted]
prior art because of the advantages
associated with its use as evidenced
above, i.e. higher through put
(Answer, page 6).
As for the claim requirement of successively forming the
second film "without exposing the first film to air," the
examiner argues that "Hirose . . . teaches performing the
ECR/CVD in a vacuum" and "this clearly suggests to one skilled
in the art that the deposition process is performed with [sic,
without] 'exposure' to air" (Answer, page 12).
The examiner's position is not well taken. As
correctly argued by the appellant, the Hirose disclosure is
limited to forming only a single film by chemical vapor
Appeal No. 1998-1216
Application 08/356,194
6
deposition. We find nothing and the examiner points to
nothing in this disclosure which would have suggested
successively forming first and second films by chemical vapor
deposition much less of forming these films without exposing
the first film to air. These last mentioned features are
disclosed only in the appellant's specification. Thus, we are
constrained to regard the examiner's obviousness conclusion as
being based on impermissible hindsight derived from the
appellant's own disclosure rather than being based upon a
teaching, suggestion, or incentive derived from the applied
prior art.
The examiner has not relied upon any of the other
applied references for a teaching or suggestion of the afore-
mentioned claim features. It follows that the previously dis-
cussed deficiency in the examiner's obviousness conclusion
taints each of the rejections advanced on this appeal. As a
consequence, we will not sustain any of these rejections.
Appeal No. 1998-1216
Application 08/356,194
7
The decision of the examiner is reversed.
REVERSED
BRADLEY R. GARRIS )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
THOMAS A. WALTZ ) APPEALS AND
Administrative Patent Judge ) INTERFERENCES
)
)
)
BEVERLY A. PAWLIKOWSKI )
Administrative Patent Judge )
BRG:psb
Appeal No. 1998-1216
Application 08/356,194
8
Hill, Steadman & Simpson
85th Floor - Sears Tower
Chicago, IL 60606