Ex Parte Richter et al

Patent Trial and Appeal Board

Sep 26, 2012

11531793 (P.T.A.B. Sep. 26, 2012)

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.
11/531,793 09/14/2006 Ralf Richter 2162.133400/DE0657 1783
10742 7590 09/26/2012
GLOBALFOUNDRIES INC.
c/o Williams, Morgan & Amerson
10333 Richmond , Suite 1100
Houston, TX 77042
EXAMINER
PHAM, THANH V
ART UNIT PAPER NUMBER
2894
MAIL DATE DELIVERY MODE
09/26/2012 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 RALF RICHTER, TOBIAS LETZ, and HOLGER SCHUEHRER
____________________

Appeal 2010-005378
Application 11/531,793
Technology Center 2800
____________________

Before JOSEPH L. DIXON, THU A. DANG, and JAMES R. HUGHES,
Administrative Patent Judges.

DANG, Administrative Patent Judge.

DECISION ON APPEAL

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I. STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134(a) from a Final Rejection of
claims 1-10 and 14-22. Claims 11-13 have been indicated as containing
allowable subject matter. We have jurisdiction under 35 U.S.C. § 6(b).
We affirm.

A. INVENTION
Appellants’ invention relates to the fabrication of integrated circuits,
and more particularly, to the formation of metallization layers and
contaminations related thereto in subsequent processes (Spec. 1, ll. 6-8).

B. ILLUSTRATIVE CLAIM
Claim 1 is exemplary:
1. A method, comprising:

selectively forming a first etch stop layer above a bevel
region of a substrate, said bevel region including a bevel
defined at an outer edge of said substrate, said first etch stop
layer covering said bevel, said substrate having a central region
adjacent to said bevel region for receiving circuit elements
therein;

forming a dielectric layer stack for a metallization layer
above said substrate and above said first etch stop layer; and

removing a portion of at least one layer of said dielectric
layer stack from said bevel region by selectively applying an
etchant to said bevel region while using said first etch stop layer
disposed above said bevel to reduce etch damage of said
substrate at said bevel.

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C. REJECTION

The prior art relied upon by the Examiner in rejecting the claims on
appeal is:
Chun US 6,607,983 B1 Aug. 19, 2003
Imaoka US 5,426,073 Jun. 20, 1995

Claims 1-10 and 14-22 stand rejected under 35 U.S.C. § 103(a) as
being unpatentable over Chun and Imaoka.

II. ISSUE
The main issue before us is whether the Examiner has erred in finding
that the combination of Chun in view of Imaoka teaches or would have
suggested forming “a first etch stop layer above a bevel region of a
substrate,” the bevel region “including a bevel defined at an outer edge of
said substrate,” and “removing a portion of at least one layer of said
dielectric layer stack from said bevel region” (claim 1). In particular, the
issue turns on whether combining Chun’s teachings of forming an etch stop
over a bevel region with Imaoka’s teaching of a bevel defined at an outer
edge of a substrate would have rendered the claims obvious.

III. FINDINGS OF FACT
The following Findings of Fact (FF) are shown by a preponderance of
the evidence.

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Chun
1. Chun’s Figure 2C is reproduced below:

Figure 2C shows a silicon nitride layer 228 formed on a structure,
thereby securing the conductive sidewall spacer 226 on the sidewall of the
first interlayer insulating layer 222 (col. 5, ll. 28-33), and a second insulating
layer 238 formed on the conductive layer 234 and on the HSG silicon 236 to
fill the openings 232 (col. 6, ll. 6-8).

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2. Chun’s Figure 2D is reproduced below:

Figure 2D shows using a photoresist pattern 240 as a mask to etch
away the second insulating layer 238 outside of the EEW line (E3) to expose
the underlying HSG silicon and the conductive layer 234 at the step portion
of the wafer edge region (A) (col. 6, ll. 21-26).

IV. ANALYSIS
As for claim 1, Appellants contend that “Chun does not teach or
suggest using an etch stop layer at the edge region to protect the substrate”
(Reply Br. 2). According to Appellants “[b]ecause the silicon nitride layer
228 does not cover the bevel, it simply cannot protect the substrate at the
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bevel” (id.). In particular, Appellants argue that “the bevel is exposed after
the removal of the layer 228, and therefore cannot be protected during the
etching of the dielectric stack” (Reply Br. 3).
However, the Examiner finds that “[t]he term ‘bevel’ is defined as …
the angle that one surface or line makes with another when they are not at
right angles” or “the slant of such a surface or line” (Ans. 11). Thus, the
Examiner finds that Chun discloses “selectively forming a first etch stop
layer 228 above a bevel region A of a substrate 210” and “removing a
portion of at least one layer of said dielectric layer stack (238, e.g.) from said
bevel region A… using said first etch stop layer 228 to reduce etch damage
of said substrate” (Ans. 3). The Examiner then concludes that though Chun
“does not show in its drawing ‘said bevel region including a bevel defined at
an outer edge of said substrate…” (id.), it would have been obvious “that
the bevel is defined at an outer edge of the substrate because the formation
of bevel defined at an outer edge is well known to those skilled in the art as
taught by Imaoka” (Ans. 4). We find no error with the Examiner’s findings
and conclusion.
We note that by arguing as to what Chun fails to teach (Reply Br. 2-
3), Appellants appear to be arguing that Chun alone fails to anticipate the
claimed invention. However, since the Examiner rejects the claims as
obvious over the combined teachings of Chun and Imaoka, the test for
obviousness is not what each reference shows but what the combined
teachings would have suggested to one of ordinary skill in the art. See In re
Merck & Co., 800 F.2d 1091, 1097 (Fed. Cir. 1986).

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Chun discloses forming a silicon nitride layer 228 on a structure,
thereby securing the conductive sidewall spacer on the sidewall of the first
interlayer insulating layer 222, and forming a second insulating layer 238 on
the conductive layer and on the HSG silicon layer (FF 1), wherein the
second insulating layer 238 is etched away to expose the underlying HSG
silicon and the conductive layer at the step portion of the wafer edge region
(FF 2). We find the silicon nitride layer to comprise a “first etch stop layer”
as recited in claim 1. In fact, even Appellants concede that “Chun clearly
shows” an “etch stop layer 228” (App. Br. 6).
Further, we find no error in the Examiner’s finding that “[t]he term
‘bevel’ is defined as … the angle that one surface or line makes with another
when they are not at right angles” (Ans. 11), and thus find the angle formed
beneath the silicon nitride layer (securing the conductive sidewall spacer) to
comprise a “bevel” above which the first etch stop layer is formed. Thus,
although Appellants argue that “the silicon nitride layer 228 does not cover
the bevel” (Reply Br. 2) and that “the bevel is exposed after the removal of
the layer 228” (Reply Br. 3), we find the “bevel region” to comprise the
angular region covered by the silicon nitride layer 228.
Furthermore, we find the second insulating layer 238 to comprise a
“layer” of a “dielectric layer stack,” wherein the second insulating layer is
removed from the bevel region. Thus, we find Chun to disclose forming “a
first etch stop layer” above a bevel region that includes “a bevel,” and
“removing a portion of at least one layer of said dielectric layer stack from
said bevel region,” as required by claim 1.

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We note that although Appellants contend that “Chun does not teach
or suggest using an etch stop layer at the edge region to protect the
substrate” (Reply Br. 2), claim 1 merely requires that the first etch stop layer
is used “to reduce etch damage” rather than positively reciting a step of
reducing etch damage. We find such “to reduce” language to merely
represent a statement of intended use of the etch stop layer which does not
limit the claim. That is, such intended use of “to reduce” will not limit the
scope of the claim because it merely defines a context in which the invention
operates. Boehringer Ingelheim Vetmedica, Inc. v. Schering-Plough Corp.,
320 F.3d 1339, 1345 (Fed. Cir. 2003). Thus, we give “to reduce etch
damage” its broadest reasonable interpretation as a layer capable of reducing
damage, as consistent with the Specification and claim 1. Since Chun
discloses an etch stop layer 228 over the bevel (FF 1-2), we find Chun to
disclose an etch stop layer that is capable of reducing etch damage to the
substrate therebelow.
Thus, we find that the only feature of Appellants’ invention missing
from Chun is an explicit teaching that the bevel is “defined at an outer edge
of said substrate” (claim 1). That is, the only claimed feature missing from
Chun is an explicit teaching that bevel region wherein the bevel formed at
the side wall spacer 226 above which the etch stop layer 228 is formed is
defined at an outer edge of the substrate 210. However, we find no error
with the Examiner’s conclusion that it would have been obvious “that the
bevel is defined at an outer edge of the substrate because the formation of
bevel defined at an outer edge is well known to those skilled in the art as
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taught by Imaoka” (Ans. 4). That is, we agree with the Examiner that the
artisan would find it obvious to define Chun’s bevel at an outer edge as
taught by Imaoka.
The Supreme Court has determined that the conclusion of obviousness
can be based on the interrelated teachings of multiple patents, the effects of
demands known to the design community or present in the marketplace, and
the background knowledge possessed by a person having ordinary skill in
the art. KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007). The skilled
artisan would “be able to fit the teachings of multiple patents together like
pieces of a puzzle” since the skilled artisan is “a person of ordinary
creativity, not an automaton.” Id. at 420-21.
Accordingly, we find that Appellants have not shown that the
Examiner erred in rejecting claim 1 over Chun and Imaoka. Since
Appellants do not provide arguments for claims 2-10 and 14-22 separate
from those of claim 1, we also find that Appellants have not shown
Examiner error in rejecting claims 2-10 and 14-22 over Chun and Imaoka.

V. CONCLUSION AND DECISION
We affirm the Examiner’s rejection of claims 1-10 and 14-22 under
35 U.S.C. § 103(a).
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)(iv).

AFFIRMED

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