Ex Parte Yang et al

Patent Trial and Appeal Board

Sep 29, 2017

13660728 (P.T.A.B. Sep. 29, 2017)

United States Patent and Trademark Office
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.
13/660,728 10/25/2012 Chung-Yuan Yang TSM12-0798 1060
43859 7590 10/03/2017
SLATER MATSIL, LLP/TSMC
17950 PRESTON ROAD, SUITE 1000
DALLAS, TX 75252
EXAMINER
JUNGE, BRYAN R.
ART UNIT PAPER NUMBER
2897
NOTIFICATION DATE DELIVERY MODE
10/03/2017 ELECTRONIC
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.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
docketing @ slatermatsil. com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte CHUNG-YUAN YANG
and JEN-PAN WANG
Appeal 2016-008649
Application 13/660,728
Technology Center 2800
Before ADRIENE LEPIANE HANLON, JAMES C. HOUSEL, and
CHRISTOPHER C. KENNEDY, Administrative Patent Judges.
HANLON, Administrative Patent Judge.
DECISION ON APPEAL
A. STATEMENT OF THE CASE
The Appellants filed an appeal under 35 U.S.C. § 134(a) from an Examiner’
decision finally rejecting claims 1, 2, 4, 5, 7, 9-11, 13, 14, 16, and 18—24, which
are all of the pending claims. We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.
The claims on appeal are directed to a metal-oxide-semiconductor field-
effect transistor (MOSFET) and a method of fabricating a MOSFET.
Representative claim 1 is reproduced below from the Claims Appendix of the
Appeal 2016-008649
Application 13/660,728
Appeal Brief dated December 22, 2015 (“App. Br.”). The limitation at issue is
italicized.
1. A metal—oxide—semiconductor field—effect transistor
(MOSFET), comprising:
a substrate;
a source in the substrate;
a drain in the substrate;
a gate electrode disposed over the substrate between the source
and drain;
an inner spacer disposed at least partially over the gate
electrode;
an outer spacer adjacent to a sidewall of the gate electrode;
an offset spacer disposed between the sidewall of the gate
electrode and the outer spacer;
a tetraethyl orthosilicate (TEOS) layer disposed between the
offset spacer and the sidewall of the gate electrode, wherein a portion
of the TEOS layer extends beneath the offset spacer, and wherein a
surface of the outer spacer facing the substrate is co-planar with a
surface of the TEOS layer facing the substrate; and
a lightly doped region disposed adjacent to the source in the
substrate, wherein the lightly doped region is self-aligned to an edge
of the offset spacer distal the gate electrode.
App. Br. 19.
The Examiner maintains the following rejections on appeal:
(1) claims 1,2,4,7,9-11, 13, 16, 19-21, 23, and 24 under 35 U.S.C.
§ 103(a) as unpatentable over Yamaguchi et al.1 in view of Song2 and Hoentschel
et al.;3
1 US 7,696,050 B2, issued April 13, 2010 (“Yamaguchi”).
2 US 5,686,331, issued November 11, 1997 (“Song”).
3 US 2011/0269278 Al, published November 3, 2011 (“Hoentschel”).
2
Appeal 2016-008649
Application 13/660,728
(2) claims 5,14, and 22 under 35 U.S.C. § 103(a) as unpatentable over
Yamaguchi in view of Song and Hoentschel, and further in view of Ohkawa;4 and
(3) claim 18 under 35 U.S.C. § 103(a) as unpatentable over Yamaguchi in
view of Song and Hoentschel, and further in view of Hung.5
B. DISCUSSION
The Examiner finds Yamaguchi discloses a MOSFET as recited in claim 1,
with the exception of, inter alia, “an inner spacer disposed at least partially over
the gate electrode.” Final 3.6
The Examiner finds Song discloses a MOSFET that includes an inner spacer
(14) as recited in claim 1. Final 3 (citing Song, col. 3,11. 7—12). The Examiner
concludes that it would have been obvious to one of ordinary skill in the art to
form an inner spacer, as disclosed in Song, in Yamaguchi’s MOSFET “to block
silicide formation with the inner spacer to increase the space by which the
source/drain and the gate can be shorted.” Final 3 (citing Song, col. 3,11. 40-45);
see also Spec. H 13, 22.
The Appellants argue that the modification proposed by the Examiner would
render Yamaguchi “unsatisfactory for its intended purpose.” App. Br. 10. More
specifically, the Appellants argue that the upper edges of the gate electrode GE in
Yamaguchi are silicided to allow a further reduction in resistance of the gate
electrode. App. Br. 11 (citing Yamaguchi, col. 9,11. 39-46). The Appellants argue
that “the proposed modification of Yamaguchi would prevent any silicidation of
the upper edge regions of Yamaguchi’s gate electrode GE” and, thus, “would
4 US 6,414,375 Bl, issued July 2, 2002 (“Ohkawa”).
5 US 5,981,325, issued November 9, 1999 (“Hung”).
6 Final Office Action dated March 31, 2015.
3
Appeal 2016-008649
Application 13/660,728
detrimentally impact Yamaguchi’s purpose of reducing the resistance of its gate
electrode GE.” App. Br. 15.
In response, the Examiner explains that the Appellants’ arguments are not
directed to the transistor relied on by the Examiner (i.e., the transistors at the left in
Yamaguchi Figures 7 and 11). Ans. 3.7 The Examiner finds that “Yamaguchi
discloses the transistor to the left in Figure 11 is not intended to include silicide
formed more deeply in the upper edge regions.” Ans. 4. Therefore, the Examiner
finds “[t]he transistor to the left in Figure 11 of Yamaguchi can be modified to
result in a transistor as claimed without rendering it unsatisfactory for its intended
purpose.” Ans. 4.
The Appellants argue that:
[FJorming Song’s second sidewall spacers 14 over upper edge regions
of the gate electrode of the transistor to the left in Figure 11 of
Yamaguchi (“the left gate electrode”) would also block silicide
formation in the upper edge regions of the left gate electrode GE,
thereby raising the resistance of the left gate electrode GE and
detrimentally impacting Yamaguchi’s purpose of providing structures
with gate electrodes having reduced resistances.
Reply Br. 2.8
Moreover, the Appellants argue that:
[T]he addition of Song’s second sidewall spacers 14 to both the left
and right gate electrodes GE of Yamaguchi’s Figure 11 would prevent
any silicidation of the upper edge regions of both the left and right
gate electrodes GE, increase the resistances of both the left and right
gate electrodes GE, and thus, frustrate Yamaguchi’s goal of providing
structures with gate electrodes having reduced resistances.
Reply Br. 4.
7 Examiner’s Answer dated July 15, 2016.
8 Reply Brief dated September 15, 2016.
4
Appeal 2016-008649
Application 13/660,728
The Appellants’ arguments are not persuasive of reversible error. First, the
Examiner is not proposing to modify both the left and right gate electrodes
depicted in Yamaguchi Figure 11 with the inner spacer of Song. See Ans. 4
(indicating that only the transistor to the left in Yamaguchi Figure 11 is being
modified). Second, although Yamaguchi discloses that the gate electrode to the
right (i.e., the N-channel type MISFET) has reduced resistance, Yamaguchi does
not disclose that the gate electrode to the left (i.e., the P-channel type MISFET)
also has reduced resistance. See Yamaguchi, col. 9,11. 1—10, 26—60. Thus, the
evidence of record does not support a finding that modifying the gate electrode to
the left, as proposed by the Examiner, would detrimentally impact Yamaguchi’s
purpose.
Finally, in the Reply Brief, the Appellants argue for the first time on appeal
that “nothing in Yamaguchi teaches or remotely suggests that the structure
disclosed therein is vulnerable to shorts [between the source/drain and the gate].”
Reply Br. 3. Thus, according to the Appellants, one of ordinary skill in the art
would not have been motivated to modify Yamaguchi as proposed by the
Examiner. Reply Br. 3.
The Appellants’ argument is not responsive to an argument raised for the
first time in the Examiner’s Answer (see Final 3), and the Appellants do not show
good cause why the argument could not have been presented in the Appeal Brief.
Therefore, the Appellants’ argument is untimely and will not be considered on
appeal. 37 C.F.R. § 41.41 (b)(2).
For the reasons set forth above, the § 103(a) rejection of claim 1 is sustained.
The Appellants do not present arguments in support of the separate patentability of
any of claims 2, 4, 5, 7, 9-11, 13, 14, 16, and 18—24. See App. Br. 16—17.
5
Appeal 2016-008649
Application 13/660,728
Therefore, the § 103(a) rejections of claims 2, 4, 5, 7, 9—11, 13, 14, 16, and 18—24
are also sustained.
C. DECISION
The Examiner’s decision 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)(1).
AFFIRMED
6