Ex Parte Ishizaka et al

Board of Patent Appeals and Interferences

Sep 11, 2012

11691167 (B.P.A.I. Sep. 11, 2012)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte
TADAHIRO ISHIZAKA, SATOHIKO HOSHINO,
KUZUHIRO HAMAMOTO, SHIGERU MIZUNO,
and YASUSHI MIZUSAWA
____________

Appeal 2010-006271
Application 11/691,167
Technology Center 2800
____________

Before MAHSHID D. SAADAT, ROBERT E. NAPPI,
and JOHN G. NEW, Administrative Patent Judges.

SAADAT, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2010-006271
Application 11/691,167

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Appellants appeal under 35 U.S.C. § 134(a) from the final rejection of
claims 1-27, which constitute all the claims pending in this application. We
have jurisdiction under 35 U.S.C. § 6(b).
We reverse.

STATEMENT OF THE CASE
Introduction
Appellants’ invention relates to a method of forming an interconnect
structure which includes an opening within a dielectric material having a
diffusion barrier formed from thermally reacting a portion of a metallic layer
with at least a portion of the dielectric material (see Spec. ¶¶ [0006] –
[0007).
Exemplary Claim
Independent claim 1 is illustrative of the invention and reads as
follows:
1. A method for fabricating an interconnect structure, the
method comprising:
depositing a metallic layer comprising a reactive metal
directly onto a dielectric material in an interconnect opening
formed within the dielectric material, wherein the dielectric
material comprises a dielectric reactant element;
thermally reacting at least a portion of the metallic layer
with at least a portion of the dielectric material onto which the
metallic layer was directly deposited to form a diffusion barrier
primarily comprising a compound of the reactive metal from
the metallic layer and the dielectric reactant element from the
dielectric material; and
filling the interconnect opening with Cu metal, wherein
the diffusion barrier surrounds the Cu metal within the
interconnect opening.
Appeal 2010-006271
Application 11/691,167

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The Rejections
Claims 1-8, 11, 13-21, 23, and 25-27 stand rejected under
35 U.S.C. § 102(b) as anticipated by Kailasam (US 2005/0181598 A1). (See
Ans. 3-8).
Claims 9, 10, 12, and 22 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over Kailasam. (See Ans. 9-11).
Claim 24 stands rejected under 35 U.S.C. § 103(a) as being
unpatentable over Kailasam and Cohen (US 2006/0249849 A1). (See Ans.
11-12).
ANALYSIS
In rejecting claims 1-8, 11, 13-21, 23, and 25-27, the Examiner finds
that Kailasam teaches the recited method of fabricating an interconnect
structure by describing depositing a boron layer on the exposed features
which reacts with the subsequently deposited ruthenium layer to form a
ruthenium boride adhesion layer (Ans. 3-4). The Examiner specifically
reads the claimed dielectric material comprising a dielectric reactant element
on the boron layer described in paragraph 32 of Kailasam (id.).
Appellants contend that the boron coating described in Kailasam is
not a “dielectric material” or a “dielectric reactant element from the
dielectric material,” as recited in claim 1 (App. Br. 4-5). The Examiner
responds by stating that “Boron inherently has the properties of a dielectric
material having a dielectric constant with poor electrical conductivity” (Ans.
13). The Examiner further asserts that the boron coating is directly over the
dielectric layer and is a part of the dielectric material (id.) and forms the
ruthenium boride layer during the in-situ reaction (Ans. 13-14). In response,
Appellants rely on known information related to boron to show conductive
Appeal 2010-006271
Application 11/691,167

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properties of boron (App. Br. 2-3) and contend that boron is not recognized
as a dielectric material and is only used as dopant to be added to dielectric
materials (Reply Br. 2). Appellants further argue that, in making the
statement that boron has dielectric properties, the Examiner has pointed to
no evidence in support of this stated position (id.).
We agree with Appellants. Kailasam’s description of the
boron layer does not identify the boron coating as a part of the dielectric
material nor identifies boron as a dielectric material (see ¶ [0032]). As such,
we find that Kailasam does not anticipate the subject matter of claim 1
because the Examiner’s assertion with respect to Kailasam teaching the
claimed “dielectric material” or a “dielectric reactant element from the
dielectric material” is not supported by evidence of record.

CONCLUSIONS
On the record before us, we find that the Examiner erred in rejecting
claim 1, as well as claims 13 and 14 which include similar limitations.
Therefore, we do not sustain the 35 U.S.C. § 102 rejection of claims 1, 13,
and 14, nor the 35 U.S.C. §§ 102 and 103 rejections of claims 2-12 and 15-
27 dependent therefrom.

DECISION
The Examiner’s decision rejecting claims 1-27 is reversed.

REVERSED

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