Appeal No. 1997-3532
Application 08/411,385
bottom of a contact hole (claim 11); forming a layer of tungsten (claim 1), which can be a derivative
thereof (claim 11), that coats all of the surfaces of the contact hole without filling the hole (claim 1), in
other words, conformally coats all of the surfaces without filling the hole (claim 11); and forming a layer
of aluminum or a derivative thereof over the tungsten layer under planarizing conditions, filling the
contact hole (claim 1), in other words, planarizing and void filling, completely filling the hole (claim 11).
While the use of the transitional term “comprising” permits the presence of other layers between the
titanium layer and the tungsten layer,6 the titanium or derivative layer and the tungsten or derivative layer
must first be in the contact hole, without filing the hole, and then the hole is filled with aluminum or
derivative in a planarizing manner. Each of claims 1 and 11 requires that the tungsten or derivative layer
is applied by chemical vapor deposition and the aluminum or derivative layer is applied by sputter
deposition under planarizing conditions.
We find that Yamaha discloses with respect to FIG. 2, that intermediate conduction path 27
comprises, in sequence, lower barrier film 28, a metal film 29 and upper barrier film 30, wherein the
metal layer can be an aluminum alloy and the lower and upper barrier layers can be titanium, titanium
silicide, tungsten, tungsten or tungsten silicide or a titanium-tungsten alloy, the layers being deposited by
ordinary sputtering, thus forming only a lower barrier layer and a non-planar metal film layer in a contact
hole (col. 3, lines 4-65).
The examiner points out that there are a number of differences between the above teachings of
Yamaha that involve each of the above noted layers and methods of forming the same required in the
claimed processes encompassed by claims 1 and 11 (answer, pages 4-5 and 9) and submits that each
of these differences represents a modification within the ordinary skill in this art as shown by the cited
prior art.
We have carefully considered the examiner’s position but find no explanation therein with
respect to the applied prior art which establishes that, prima facie, one of ordinary skill in this art would
have found in the combined teachings of the applied prior art a suggestion to arrive at the sequence of
6 See In re Baxter, 656 F.2d 679, 686-87, 210 USPQ 795, 802-03 (CCPA 1981) (“As long as one
of the monomers in the reaction is propylene, any other monomer may be present, because the term
‘comprises’ permits the inclusion of other steps, elements, or materials.”).
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