Lam Research Corporation

Patent Trials and Appeals Board

Mar 26, 2021

2020002898 (P.T.A.B. Mar. 26, 2021)

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.
14/576,978 12/19/2014 Tom A. Kamp LAM1P492/3541-1US 5865
105653 7590 03/26/2021
Beyer Law Group LLP/Lam
P. O. Box 51887
Palo Alto, CA 94303-1887
EXAMINER
PHAM, THOMAS T
ART UNIT PAPER NUMBER
1713
NOTIFICATION DATE DELIVERY MODE
03/26/2021 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):
USPTOmail@beyerlaw.com
eofficeaction@appcoll.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte TOM A. KAMP, ALEXANDER M. PATERSON,
and NEEMA RASTGAR
Appeal 2020-002898
Application 14/576,978
Technology Center 1700
Before JEFFREY T. SMITH, MICHAEL P. COLAIANNI, and
SHELDON M. MCGEE, Administrative Patent Judges.
MCGEE, Administrative Patent Judge.
DECISION ON APPEAL
Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the
Examiner’s decision to reject claims 1–17. We have jurisdiction.
35 U.S.C. § 6(b).
We affirm.

1 We use the word “Appellant” to refer to “applicant” as defined in 37
C.F.R. § 1.42. Appellant identifies the real party in interest as Lam
Research Corporation. Appeal Br. 3.
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Application 14/576,978

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CLAIMED SUBJECT MATTER
The claims are directed to in-situ methods of etching and cleaning
silicon-containing layers within the same plasma processing chamber. In the
claimed methods, the etch gas and dry clean gas are converted into etch
plasma and dry clean gas plasma, respectively, in the plasma processing
chamber where the silicon-containing layer is housed. According to
Appellant, such methods are known in the art as a “direct plasma process,”
as opposed to a “remote plasma process.” Appeal Br. 5.
Claim 1, reproduced below, is illustrative of the claimed subject
matter:
1. An in-situ method for etching features into and cleaning a
silicon containing etch layer in a plasma processing chamber
having an external TCP coil and a wafer support, comprising
placing the silicon containing etch layer into the plasma
processing chamber;
flowing an etch gas into the plasma processing chamber;
providing TCP power from the TCP coil to the plasma
processing chamber to form the etch gas into an etch plasma in
the plasma processing chamber, the etch plasma located between
the external TCP coil and the wafer support, wherein the silicon
containing etch layer is exposed to the etch plasma, and wherein
the etch plasma etches features into the silicon containing etch
layer leaving silicon containing residue;
stopping the flow of etch gas into the plasma processing
chamber;
flowing a dry clean gas into the plasma processing
chamber, wherein the dry clean gas comprises NH3 and NF3;
providing TCP power from the TCP coil to the plasma
processing chamber to form the dry clean gas into a dry clean gas
plasma in the plasma processing chamber between the external
TCP coil and the wafer support, wherein the silicon containing
residue is exposed to the dry clean gas plasma, and wherein the
dry clean gas plasma converts at least some of the silicon
containing residue into ammonium containing compounds;
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stopping the flow of the dry clean gas; and
removing the silicon containing etch layer from the plasma
processing chamber.
REJECTIONS
The Examiner rejects the following claims under 35 U.S.C. § 103:
I. Claims 1–12 and 14–17 over Nemani,2 Kamp,3 and Sato4 as
evidenced by Tang5;
II. Claim 13 over Nemani, Kamp, Sato, and Chen6 as evidenced by
Tang; and
III. Claims 1–17 over Chang,7 Woo,8 and Sato as evidenced by
Tang.
OPINION
We review the appealed rejection for reversible error based on the
arguments and evidence presented by Appellant. 37 C.F.R.
§ 41.37(c)(1)(iv); Ex parte Frye, 94 USPQ2d 1072, 1075 (BPAI 2010)
(precedential) cited with approval in In re Jung, 637 F.3d 1356, 1365 (Fed.
Cir. 2011) (explaining that even if the Examiner had failed to make a prima
facie case, “it has long been the Board’s practice to require an applicant to
identify the alleged error in the examiner’s rejections”). Having reviewed

2 US 2014/0120726 A1, published May 1, 2014.
3 US 2004/0084406 A1, published May 6, 2004.
4 US 8,633,119 B2, issued Jan. 21, 2014.
5 US 2011/0151674 A1, issued June 23, 2011.
6 US 7,816,227 B2, issued Oct. 19, 2010.
7 US 9,023,723 B2, issued May 5, 2015.
8 US 2015/0000844 A1, issued Jan. 1, 2015.
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the appeal record, we affirm the obviousness rejections for the reasons
provided by the Examiner and below. Final Act. 4–13; Ans. 8–11.
Rejection I
The Examiner rejects claims 1–12 and 14–17 over the combined
disclosures of Nemani, Kamp, and Sato, as evidenced by Tang. Final Act.
4–8. Specifically, the Examiner finds that Nemani teaches an in-situ method
for etching and cleaning a porous silicon dioxide layer by performing two
plasma processes. Id. at 5. The Examiner finds that each of these processes
may be performed in a plasma etch chamber. Id. The Examiner finds that
Nemani is silent, however, regarding the precise method of igniting the
plasma. Id. at 6.
To address this difference between the prior art and the claims, the
Examiner turns to Kamp, which the Examiner finds teaches that the plasma
may be ignited by a TCP coil. Id. The Examiner additionally finds that Sato
teaches using a combination of ammonia and nitrogen trifluoride plasma and
that such “plasma may be formed within the chamber supporting the
substrate.” Id. Based on the combined disclosures of Nemani, Kamp, and
Sato, the Examiner determines that it would have been obvious to use a TCP
coil as the plasma ignition device in Nemani’s method. Id.
Appellant addresses the rejected claims as a group. Appeal Br. 10–13.
We, therefore, select claim 1 as representative and decide the appeal of this
rejection on the basis of claim 1 alone. 37 C.F.R. § 41.37(c)(1)(iv).
Appellant argues that “Kamp does not disclose or suggest cleaning the
wafer using dry clean plasma” or “etching features into and cleaning a wafer
post-etch by applying TCP power.” Appeal Br. 10. We are not persuaded
by this argument because it focuses on the disclosure of Kamp alone without
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considering the teachings of Nemani. Here, the Examiner relies on Nemani
to evince every recited limitation except for the use of TCP power––
including etching and cleaning a wafer post-etch. Final Act. 4–6. Thus, it is
insufficient for Appellant to point out that Kamp does not disclose process
steps for which it was not relied upon. In re Merck & Co., 800 F.2d 1091,
1097 (Fed. Cir. 1986) (“Non-obviousness cannot be established by attacking
references individually where the rejection is based upon the teachings of a
combination of references. . . . [The reference] must be read, not in
isolation, but for what it fairly teaches in combination with the prior art as a
whole.”).
Appellant next argues that Nemani discloses two types of plasma
processes: a “direct” (e.g., “non-remote”) plasma process that deposits a
protective layer, and a “remote” plasma process which cleans the surface by
removing the protective layer and modified low-k material. Appeal Br. 11;
see also id. at 11–13 (arguing how Nemani’s second process is a “remote”
process). Appellant asserts that the skilled artisan would have understood
that TCP power is not used in a remote plasma generation process. Id. at 10.
Thus, according to Appellant, the skilled artisan would not have been
motivated to apply TCP power to Nemani’s process. Id. at 13.
We are not persuaded by this argument because it attempts to
improperly narrow the breadth of Nemani’s disclosure. First, Appellant
acknowledges that Nemani’s two stage process occurs in the same
processing chamber. Appeal Br. 11. Such in-situ processing appears to
meet Appellant’s description of the claimed “direct” process. See id. at 10
(where Appellant asserts that a direct plasma process is “where etch gas and
dry clean gas are both flowed into the plasma processing chamber”).
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Appellant also provides a Declaration from inventor Tom A. Kamp9
supporting this description. See Kamp Decl. ¶ 6 (testifying that “[a] direct
plasma process is a plasma process in which the interaction between the
plasma and the semiconductor substrate takes place where the gas is formed
into a plasma” and that “in a direct plasma processing apparatus . . . a gas
(e.g., etch gas or dry clean gas) is converted into a plasma in the same space
in which the plasma interacts with the semiconductor substrate.” (emphases
added)).
Furthermore, while Nemani discusses certain embodiments which use
remote plasma processing post-etch (see, e.g., Nemani ¶¶ 24, 56, 62), the
full scope of Nemani’s disclosure is not limited to those embodiments. For
example, Nemani generally discloses flowchart 200 having two plasma
operations 204, 206 after mask layer formation. Nemani, Fig. 2, ¶¶ 34, 39.
Although Appellant asserts that Nemani’s second stage, i.e., operation 206,
is a remote plasma process, Nemani does not describe operation 206 as one
that can only be carried out remotely. Id. ¶ 39. In fact, Nemani suggests
that operation 206 can be carried out by a “direct” plasma process. See id.
¶ 58 (disclosing an embodiment where “one or more of the above processes
is performed in a plasma etch chamber” and where one of those “above
processes” is operation 206 depicted in Figure 2 (emphasis added)); see also
Final Act. 5 (finding that “all processes” in Nemani, including the removal
process, “may be performed in a plasma etch chamber” (citing Nemani
¶ 58)). “It is well settled that a prior art reference is relevant for all that it
teaches to those of ordinary skill in the art.” In re Fritch, 972 F.2d 1260,

9 Declaration executed by Tom A. Kamp dated November 17, 2017 (“Kamp
Decl.”).
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1264 (Fed. Cir. 1992). Therefore, we are not persuaded that the skilled
artisan would have viewed Nemani’s disclosure as narrowly as Appellant
urges.
Rejection I is sustained.
Rejection II
Claim 13 is similar to claim 1, but is directed to a method of etching
and cleaning “a silicon wafer, a source layer, a drain layer, or a polysilicon
layer” instead of “a silicon containing etch layer” as recited in in claim 1.
Appeal Br. 21 (Claims App.).
Given these similarities, the Examiner relies on Nemani, Kamp, and
Sato as set forth in Rejection I for most of the limitations recited in claim 13,
but turns to Chen to undisputedly evince the claimed details of the silicon
substrate, and to determine the claimed method would have been obvious.
Final Act. 8–9; Appeal Br. 13–14.
Appellant presents arguments about a specific embodiment depicted
in Nemani’s Figure 5B––an embodiment not expressly relied upon by the
Examiner (Final Act. 4–10). In the context of Nemani’s Figure 5B
embodiment, Appellant repeats its deficient arguments regarding a remote
plasma process vis-à-vis the claimed direct plasma process. Appeal Br. 13–
14.
We are unpersuaded by this line of argument because it does not
adequately address the rejection as set forth by the Examiner, and again
seeks to narrow the breadth of Nemani’s disclosure as discussed with respect
to Rejection I. Appeal Br. 13–14.
Rejection II is sustained.

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Rejection III
The Examiner additionally rejects claims 1–17 using different
references than those relied on in Rejections I and II. Final Act. 10–13.
Specifically, with respect to claim 1, the Examiner finds that Chang teaches
a method of etching and cleaning a silicon oxide layer, but is silent regarding
the specific details of the etching and cleaning steps. Id. at 10. The
Examiner additionally finds that Woo teaches the use of a TCP plasma
generator to carry out plasma etching and plasma cleaning, and that Sato
teaches forming a NH3/NF3 plasma in the same chamber as the substrate to
clean the layer. Id. at 10–11. Based on these combined teachings, the
Examiner determines it would have been obvious to employ a TCP plasma
generator in the same plasma apparatus using Chang’s method to simplify
manufacturing. Id.
Appellant addresses this rejection as a group. Appeal Br. 15–17. We,
therefore, select claim 1 as representative and decide the appeal of this
rejection on the basis of claim 1 alone. 37 C.F.R. § 41.37(c)(1)(iv).
Appellant argues that Woo teaches away from using the same plasma
supply apparatus for etching and cleaning. Appeal Br. 15–16. This
argument is not persuasive because it mischaracterizes the teachings of Woo.
Woo ¶¶ 6, 8. Woo discloses that separating the etching and cleaning
processes into different apparatuses suffers from “degraded” efficiency, and
“provide[s] a multiple-mode plasma generation apparatus that is capable of
supplying plasma in multiple processes to improve processing efficiency.”
Id. Thus, Woo teaches the opposite of what Appellant’s argument suggests.
Appellant also argues that Tang discloses “remote” plasma
processing. Appeal Br. 16. This argument is unpersuasive because it
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addresses the disclosure of Tang in a vacuum and does not address the
collective teachings of the relied-upon prior art. In re Merck & Co., 800
F.2d at 1097.
Appellant also makes several arguments regarding Nemani and Kamp,
but we do not consider such arguments because these references were not
relied on in this rejection.
Rejection III is sustained.
CONCLUSION
The Examiner’s rejections are affirmed.
DECISION SUMMARY
Claim(s)
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1–12, 14–
17
103 Nemani, Kamp,
Sato, Tang
1–12, 14–17
13 103 Nemani, Kamp,
Sato, Chen, Tang
13
1–17 103 Chang, Woo, Sato,
Tang
1–17
Overall
Outcome:
1–17
TIME PERIOD FOR RESPONSE
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