Ex Parte Huang et al

Patent Trial and Appeal Board

Jul 16, 2014

12879371 (P.T.A.B. Jul. 16, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte KUO BIN HUANG, HSIN-CHIEN LU, RYAN CHIA-JEN CHEN,
CHI-MING YANG, CHYI SHYUAN CHERN,
and CHIN-HSIANG LIN

Appeal 2012-005439
Application 12/879,371
Technology Center 2800
____________

Before MURRIEL E. CRAWFORD, MICHAEL C. ASTORINO, and
JAMES A. WORTH, Administrative Patent Judges.

WORTH, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s final
rejection of claims 1–17, which constitute all the claims pending in this
application. 1, 2 We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.

1 We refer to the Appeal Brief (filed Nov. 14, 2011, hereinafter “App. Br.”),
the Reply Brief (filed Feb. 21, 2012, hereinafter “Reply Br.”), and the
Answer (mailed Dec. 23, 2011, hereinafter “Ans.”) for the respective
positions of Appellants and the Examiner.
2 The real party in interest identified by Appellants is Taiwan
Semiconductor Manufacturing Company, Ltd. App. Br. 3.
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Introduction
Appellants’ disclosure relates to a method of cleaning carbon-
containing organic residues from the high-k gate dielectric layer of a
semiconductor device. Spec. ¶¶ 5, 11.
Claims 1, 6, and 10 are the independent claims on appeal. Claim 1 is
illustrative and reads as follows:
1. A method for forming an integrated circuit, the method
comprising:
forming a gate dielectric structure over a substrate;
forming a titanium-containing sacrificial layer contacting
the gate dielectric structure;
generating a product by causing an interaction between
the titanium-containing sacrificial layer and carbon-containing
organic residues residing on the gate dielectric structure; and
substantially removing the whole titanium-containing
sacrificial layer and the product.

App. Br. 19, Claims App.

Prior Art Relied Upon
Chau 7,166,505 B2 Jan. 23, 2007
Jung 2007/0178637 A1 Aug. 2, 2007
Kraus 2008/0076268 A1 Mar. 27, 2008
Chudzik 2009/0294920 A1 Dec. 3, 2009

Rejections On Appeal
The Examiner maintains, and the Appellants appeal, the following
rejections:
1) Claims 1–4 and 6–9 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over Chau and Kraus;
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2) Claims 5 and 10–14 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over Chau, Kraus, and Jung; and
3) Claims 15–17 stand rejected under 35 U.S.C. § 103(a) as being
unpatentable over Chau, Kraus, Jung, and Chudzik.

ANALYSIS
Claim 1
The Examiner finds that Chau substantially describes the method of
claim 1 to remove impurities from a high-k dielectric layer, but Chau does
not describe that such impurities include carbon-containing organic residues.
Ans. 5–6. The Examiner finds that Kraus describes that impurities on a
high-k dielectric layer include carbon-containing residues. Id. at 6 (citing
Chau, col. 2, ll. 28-42 and Kraus ¶ 4). The Examiner concludes that it would
have been obvious to use the method of Chau to remove contaminants,
including carbon-containing residues, from a high-k dielectric material
because Chau and Kraus both use a conventional deposition method to
deposit the high-k dielectric layer. Id. at 6 (citing Chau, col. 2, ll. 28–42).
Ans. 6.
Appellants argue that the proposed combination of Chau and Kraus
would improperly change the principle of operation of the two references
(App. Br. 14; Reply Br. 4 (citing In re Ratti, 270 F.2d 810, 813 (CCPA
1959))), and the Examiner never articulated reasoning sufficient to support
the proposed combination. Reply Br. 5 (citing KSR, 550 U.S. 398, 418
(2007)). We are not persuaded by Appellants’ argument. As the Examiner
observes, Chau teaches the addition of a sacrificial layer to remove
impurities from the dielectric layer. Ans. 6 (citing Chau, col. 2, lines 28–
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59). Indeed, Chau teaches that, “[s]acrificial layer 102 preferably is made
from a material that may getter impurities from dielectric layer 101.” Chau,
col. 2, lines 52–53. We agree with the Examiner that a person of ordinary
skill would have combined the teachings of Chau and Kraus because both
describe impurities in a dielectric layer formed by a conventional deposition
method. Ans. 15–16. We further agree with the Examiner that Chau has the
same function as claim 1 to remove impurities. See Ans. 15.
Appellants argue that the only examples in Chau of the transfer of
impurities is the transfer of hydrogen and unreacted metal. Reply Br. 4
(citing Chau, col. 3, lines 4–5). Appellants are referring to the following
example in Chau: “FIG. 1b represents a structure in which undesirable
impurities, e.g., hydrogen and unreacted metal (represented by dots in FIG
1b), have been transferred from high-k dielectric layer 101 into titanium
nitride layer 102.” Chau, col. 3, lines 4–7. The list of impurities in Chau is
not limited to a chemical species or type of chemical species, and further,
this is an inexhaustive list, as denoted by the term, “e.g.” meaning, for
example. Therefore, Appellants’ argument is unpersuasive.
Appellants assert that Chau describes a metal oxide precursor for the
high-k dielectric layer (App. Br. 14 (citing, inter alia, Chau, col. 2, lines 32–
37); Reply Br. 4–5), and further assert that Chau is best understood as a
carbon-free process. App. Br. 14. Appellants state that the only mention of
carbon in Chau is in the title of a publication, listed in the “References
Cited” section of the patent document, entitled “Chemical Vapor Deposition
of the Oxides of Titanium, Zirconium and Hafnium for Use as High-K
Materials in Microelectronic Devices. A Carbon-Free Precursor for the
Synthesis of Hafnium Oxide.” Id. (emphasis in brief). However, this
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publication is not referred to in the written description of Chau and Chau
does not state that it used such a process. Further, the Examiner’s rejection
is based on the combination of Chau and Kraus.
Appellants argue that Kraus, without more, cannot be sufficient to
lead to a conclusion that the chemical vapor deposition (“CVD”) carbon-
containing precursor process in Kraus may be used to replace a conventional
CVD metal oxide precursor process in Chau. Reply Br. 6. Specifically,
Appellants contend that Kraus is not sufficiently early to show that a CVD
process using a carbon-containing precursor is “a conventional CVD”
process in Chau. Reply Br. 5–6. Nevertheless, the conventionality of the
processes of Chau and Kraus is only relevant for the question of whether it
would have been obvious to a person of ordinary skill to use a titanium-
containing sacrificial layer to remove impurities, including carbon.
Finally, Appellants argue that the principle of operation of Kraus
would be changed in the combination with Chau. App. Br. 15. The
Examiner responds that the combination does not rely on the fluorination
process of Kraus, but only on the teaching that carbon impurities may form
in a dielectric layer. Ans. 15–16. We agree.
We will sustain the Examiner’s rejection of claim 1 under 35 U.S.C.
§ 103(a).

Claims 2–17
Although we understand that the Examiner’s rejections of claims 2–4
and 6–9, claims 5 and 10–14, and claims 15–17 are based on three separate
grounds of rejection, which are addressed under separate headings by
Appellants, Appellants do not argue these grounds of rejection separately
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from the rejection of claim 1. Therefore, Appellants’ arguments are
unpersuasive for the same reasons as for claim 1. We will sustain the
Examiner’s rejections of claims 2–17 under 35 U.S.C. § 103(a).

DECISION
The decision of the Examiner to reject claims 1–17 is affirmed.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R.
§ 1.136(a)(1)(iv).

AFFIRMED

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