Ex Parte Lin et al

Patent Trial and Appeal Board

Oct 29, 2013

12322118 (P.T.A.B. Oct. 29, 2013)

UNITED STATES PATENT AND TRADEMARKOFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
12/322,118 01/27/2009 Wei-Jung Lin N1085-00586 6209
54657 7590 10/29/2013
DUANE MORRIS LLP (TSMC)
IP DEPARTMENT
30 SOUTH 17TH STREET
PHILADELPHIA, PA 19103-4196
EXAMINER
PHAM, THANH V
ART UNIT PAPER NUMBER
2899
MAIL DATE DELIVERY MODE
10/29/2013 PAPER
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL
AND APPEAL BOARD
____________

Ex parte WEI-JUNG LIN,
CHENG-TUNG LIN,
CHIH-WEI CHANG, and
SHAU-LIN SHUE
__________

Appeal 2011-008198
Application 12/322,118
Technology Center 2800
____________

Before ROMULO H. DELMENDO, MARK NAGUMO, and
MICHAEL P. COLAIANNI, Administrative Patent Judges.

COLAIANNI, Administrative Patent Judge.

DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134 the final rejection of claims
1-10. We have jurisdiction over the appeal pursuant to 35 U.S.C. § 6(b).
We REVERSE.
Appellants’ invention is directed to a semiconductor device with a
controlled work function defined as “the minimum energy needed to remove
an electron from the Fermi level in a metal to a point at infinite distance
Appeal 2011-008198
Application 12/322,118

2
away outside the surface” (Spec. paras. [0002], [0007]). The device includes
silicide layers of a first phase (e.g., NiSi) and a second phase (e.g., Ni2Si) to
tune or optimize the work function of the device for a particular application.
(Spec. paras. [0005], [0015]).
Claim 1 is illustrative:
1. A semiconductor device comprising:
a semiconductor substrate;
a gate dielectric disposed over the substrate;
a first metal silicide layer disposed over the gate dielectric, wherein
the first metal silicide has a first phase; wherein the first metal silicide layer
comprises at least one alloy element; and
a second metal silicide layer disposed over the first metal silicide
layer, wherein the second metal silicide has a second phase; wherein the first
metal silicide and second metal silicide comprise the same metal and the
first and second phases are different.

Appellants appeal the following rejections:
1. Claims 1-5 are rejected under 35 U.S.C. § 102(a), as being
unpatentable over Liu1 (US 2006/0084247 A1, published Apr. 20,
2006).
2. Claims 6-10 are rejected under 35 U.S.C. §§ 102(a)/103(a) as being
unpatentable over Liu.

1 As argued in the Reply Brief filed April 20, 2011 at pages 4-5, the
Examiner relies on Nishida (US Patent 5,384,485) for the first time in the
Response to Arguments section of the Answer to support the § 102(a)
rejection over Liu (Ans. 3, 5-6). We shall not consider Nishida because
where a reference is relied on to support a rejection, whether or not in a
“minor capacity,” there would appear to be no excuse for not positively
including the reference in the statement of the rejection. In re Hoch, 428
F.2d 1341, 1342 n. 3 (CCPA 1970).
Appeal 2011-008198
Application 12/322,118

3

ISSUE
Did the Examiner reversibly err finding that Liu discloses forming a second
metal silicide layer disposed over a first metal silicide layer on a gate
dielectric wherein the second metal silicide layer has a second phase
different than the first phase of the first metal silicide layer as required by
claim 1? We decide this issue in the affirmative.

FINDINGS OF FACT AND ANALYSES
Appellants argue that Liu fails to teach two metal silicide layers over
the gate dielectric (App. Br. 7). Appellants contend that is in unclear what
the resulting structure is from Liu’s second annealing step that forms the
NiSi layer 390 over the source and drain (S/D) regions of the semiconductor
and somewhat nickel enriches the higher resistivity nickel disilicide gate 380
(Reply Br. 3-4; Liu’s Fig. 3G and para. [0184]). Appellants contend that
Liu’s disclosure fails to teach a second silicide layer as recited in claim 1.
Id.
The Examiner responds that paragraph 184 of Liu discloses that the
annealing treatment to form the NiSi layer over the source and drain region
of the semiconductor device somewhat enriches the nickel disilicide gate
layer, which results in a nickel-enriched silicide layer (Ans. 4, 5).
However, the Examiner’s inherency position is improperly based
upon possibilities and probabilities that the claimed second silicide layer
results from the nickel enriching of the nickel disilicide gate layer. In re
Oelrich, 666 F.2d 578, 581 (CCPA 1981)). The claim requires that the
second silicide layer have a second phase different than the phase of the first
Appeal 2011-008198
Application 12/322,118

4
silicide layer (claim 1). It is unclear whether the “somewhat nickel
enriched” nickel disilicide layer 380 disclosed in Liu results in a nickel layer
having a different phase or whether nickel from the nickel layer 350 used to
form the NiSi layer over the source and drain regions simply results in more
nickel being present in the surface region of the nickel disilicide layer 380
with no change in the phase. While the Examiner contends that Liu’s post
annealing step would provide another layer of silicide of a different phase
(Ans. 6), the Examiner has not provided a basis-in-fact or technical
reasoning to support the finding that a second silicide layer as recited in
claim 1 forms via the nickel enrichment of the metal disilicide gate material.
Ex parte Levy, 17 USPQ2d 1461, 1464 (BPAI 1990).
On this record, the Examiner has not dispensed with the burden of
establishing a prima facie case of anticipation. Because claim 1 is the only
independent claim on appeal and the Examiner does not address the above-
mentioned shortcomings of Liu in the context of the § 103 rejection of
claims 6-10, we reverse the Examiner’s § 102 and § 103 rejections.

DECISION
The Examiner’s decision is reversed.

ORDER
REVERSED

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