Ex Parte Xie

Patent Trial and Appeal Board

Mar 9, 2018

14175217 (P.T.A.B. Mar. 9, 2018)

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.
14/175,217 02/07/2014 Ruilong Xie 2162.239300/EU455 6092
10742 7590 03/13/2018
OT OR AT FOT TNDR TFS TNO
EXAMINER
c/o Amerson Law Firm, PLLC IDA, GEOFFREY H
2500 Fondren Road, Suite 220
Houston, TX 77063 ART UNIT PAPER NUMBER
2892
NOTIFICATION DATE DELIVERY MODE
03/13/2018 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):
uspto @ amersoniplaw.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte RUILONG XIE
Appeal 2017-006507
Application 14/175,217
Technology Center 2800
Before ROMULO H. DELMENDO, JEFFREY T. SMITH,
and MICHAEL G. McMANUS, Administrative Patent Judges.
McMANUS, Administrative Patent Judge.
DECISION ON APPEAL
The Examiner finally rejected claims 1—9, 13, and 28—41 of
Application 14/175,217 as unpatentable under 35 U.S.C. § 103. Final Act.
(Feb. 1, 2016) 2—23. Appellant1 seeks reversal of these rejections pursuant
to 35 U.S.C. § 134(a). We have jurisdiction under 35 U.S.C. § 6.
For the reasons set forth below, we AFFIRM.
1 Appellant is the Applicant, GLOBALFOUNDRIES INC., which is also
identified as the real party in interest. Appeal Br. 2.
Appeal 2017-006507
Application 14/175,217
BACKGROUND
The present application generally relates to methods of forming
contacts to semiconductor devices using a bottom etch stop layer. Spec. 1.
Claim 1, which is representative of the claims at issue, is reproduced
below:
1. A method of forming a transistor in and above a
semiconductor substrate, said transistor comprising a gate
structure, a sidewall spacer positioned adjacent sidewalls of
said gate structure, and an epitaxially formed semiconductor
material in source/drain regions of said transistor, wherein the
method comprises:
forming a conformal layer of high-ketch stop material
having a k-value of approximately 8 or greater above said
gate structure and said epitaxially formed semiconductor
material, said conformal layer of high-k etch stop material
extending continuously over and covering an entire upper
surface of said epitaxially formed semiconductor material
and all outer surfaces of said sidewall spacer extending
above said epitaxially formed semiconductor material;
forming a patterned high-ketch stop layer from said
conformal layer of high-ketch stop material, said
patterned high-k etch stop layer covering a portion of said
sidewall spacer and said entire upper surface of said
epitaxially formed semiconductor material in said
source/drain regions of said transistor;
forming at least one layer of insulating material above
said patterned high-k etch stop layer;
performing at least one contact opening etching process to
form at least one contact opening in said at least one layer
of insulating material, wherein said patterned high-k etch
stop layer acts as an etch stop during said at least one
contact opening etching process;
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Application 14/175,217
performing an etching process to remove portions of said
patterned high-k etch stop layer exposed by said at least
one contact opening; and
forming a conductive contact in said at least one contact
opening that is conductively coupled to said epitaxially
formed semiconductor material in at least one of said
source/drain regions of said transistor.
Appeal Br. (Claims App., A-l to A-2).
REJECTIONS
The Examiner maintains the following rejections:
1. Claims 1, 2, 6, 7, 9, 13, 29, 32, 33, 38, and 39 are rejected under
35 U.S.C. § 103 as obvious over Alptekin2 in view of Tu3 Final
Act. 2-11.
2. Claims 3, 4, 30, and 37 are rejected under 35 U.S.C. § 103 as
obvious over Alptekin in view of Tu and further in view of
Kavalieros4. Id. at 11—14.
3. Claims 5, 8, 28, 31, 34, and 40 are rejected under 35 U.S.C. § 103
as obvious over Alptekin in view of Tu and further in view of
Mehrotra5. Id. at 14—18.
4. Claims 35 and 36 are rejected under 35 U.S.C. § 103 as obvious
over Alptekin in view of Tu and further in view of Hobbs6. Id. at
18-19.
2 US 2015/0129939 Al, published May 14, 2015.
3 US 2013/0095644 Al, published Apr. 18, 2013.
4 US 2006/0022277 Al, published Feb. 2, 2006.
5 US 2013/0214289 Al, published Aug. 22, 2013.
6 US 6,171,910 Bl, issued Jan. 9, 2001.
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Application 14/175,217
5. Claim 41 is rejected under 35 U.S.C. § 103 as obvious over
Alptekin in view of Tu and further in view of Hobbs. Id. at 19—23.
DISCUSSION
Rejection 1. The Examiner rejected claims 1, 2, 6, 7, 9, 13, 29, 32,
33, 38, and 39 as obvious over Alptekin in view of Tu. Id. at 2—11.
In support of such rejection, the Examiner found that Alptekin teaches
most elements of the claims. Id. at 2—3. Specifically, the Examiner found
that Alptekin teaches a patterned high-k etch stop layer 310. Id. at 3. The
Examiner further found, however, that Alptekin does not explicitly teach a
“high-k etch stop layer on all outer surfaces of said sidewall spacer
extending above said epitaxially formed semiconductor material.” Id. at 4.
In this regard, the Examiner found that Tu teaches “a method of forming a
transistor comprising high-k etch stop layer 302 (| [20]) on all outer surfaces
of said sidewall spacer 212 (| [18]) extending above said epitaxially formed
semiconductor material 202 (| [11]).” Id. The Examiner further found that
one of ordinary skill in the art would have been motivated to modify
Alptekin with the continuous high-k etch stop layer (302) of Tu so as to
protect the spacers and source/drain regions from damage during further
processing steps. Id.
Appellant asserts error in the combination of the teachings of Alptekin
and Tu. Appeal Br. 7—11. Appellant asserts that Alptekin teaches away
from a continuous etch stop layer. In particular, Alptekin teaches as follows:
The trouble with a conventional conformal nitride is that the
narrow width (W in FIG. 2) of the contact area prevents a
sufficiently thick film without having issues due to deposition
on the spacer sidewalls, making a very narrow, and possibly
irregularly shaped area for which to make contact with
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Application 14/175,217
source/drain regions 308. By utilizing a horizontally formed
contact etch stop layer 310, the aforementioned problems are
mitigated.
Alptekin 126. In view of such teaching, Appellant argues that a person of
ordinary skill in the art would not have been motivated to combine the
conformal layer of Tu with the high aspect ratio features of Alptekin.
Appeal Br. 9—10. Appellant further contends that a substitution of a
conformal etch stop layer for the horizontal etch stop layer of Alptekin
would “predictably lead to defective nonfunctional devices.” Id. at 10.
In response, the Examiner determines that “contact areas that are
irregular in shape or narrow can still provide contact locations, creating a
functioning device.” Answer 3. The Examiner further determines that
Appellant’s contention that a conventional conformal layer would cause the
devices to be defective is mere attorney argument. Id. at 3^4. Similarly, the
Examiner argues that a reference may be relied upon for all that it teaches,
including nonpreferred embodiments. Id. at 4. Finally, the Examiner
determines that there was sound reason to combine the teachings of Alptekin
and Tu and that such combination is not the result of improper hindsight. Id.
at 5.
“A reference ‘teaches away’ when it ‘suggests that the line of
development flowing from the reference’s disclosure is unlikely to be
productive of the result sought by the applicant.’” Santarus, Inc. v. Par
Pharm., Inc., 694 F.3d 1344, 1354 (Fed. Cir. 2012). “[T]he nature of the
teaching is highly relevant, and must be weighed in substance. A known or
obvious composition does not become patentable simply because it has been
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Application 14/175,217
described as somewhat inferior to some other product for the same use.” In
re Gurley, 27 F.3d 551, 553 (Fed. Cir. 1994).
Here, Alptekin indicates that, in the context of an integrated circuit
having high aspect ratio contacts, a “conventional conformal nitride” (which
would cover the vertical walls of spacers 306) may partially block the
contact cavity yielding “a very narrow, and possibly irregularly shaped area
for which to make contact with source/drain regions.” Alptekin 126. This
drawback is, apparently, inapplicable to etch stop layers that have a lesser
thickness such as those of hafnium oxide. Id. (“[w]ith other materials, the
thickness T can be reduced.”).
Further, such drawback is limited to integrated circuits having high
aspect ratio contacts. The high aspect ratio contacts of Alptekin have a
height-to-width ratio of five or more. Id. 122. There is no reason to find
that one of ordinary skill in the art would avoid use of a “conventional”
conformal etch stop layer in making an integrated circuit of conventional
dimensions. The claims at issue do not include any limitations pertaining to
height and width. Accordingly, Applicant has not shown error in the
Examiner’s finding that the cited portion of Alptekin would not discourage
one of skill in the art from the use of a conventional conformal layer as
taught by Tu.
Appellant further argues that the Examiner has not stated an adequate
basis as to why one of skill in the art would have substituted the conformal
deposition process of Tu for the GCIB deposition process of Alptekin.
Appeal Br. 11. As above, Appellant asserts that such substitution would
lead “to the type of device defects that the Alptekin method was specifically
developed to avoid.'” Id. This, however, is merely a restatement of
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Appellant’s argument that Alptekin teaches away from the use of a
conformal deposition layer. Appellant does not show error in the
Examiner’s facially sound determination that one of skill in the art would
have had reason to modify Alptekin so as to include the etch stop layer on all
outer surfaces of the sidewall spacer so as to protect the sidewall spacers
from damage during subsequent processing steps. Id.', Final Act. 4.
Accordingly, Appellant has not shown error in the Examiner’s
determination that a person of ordinary skill in the art would have had reason
to combine the teachings of Alptekin and Tu.
Rejections 2—5. Appellant relies upon the foregoing arguments in
seeking reversal of all other rejections. Appeal Br. 11—13. As we have
found such arguments insufficient to show reversible error in the Examiner’s
determination, we affirm for the reasons stated above.
DECISION
The rejections of claims 1—9, 13, and 28-41 are 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).
AFFIRMED
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