Ex Parte Wang et al

Patent Trial and Appeal Board

Jun 21, 2018

13174090 (P.T.A.B. Jun. 21, 2018)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
13/174,090 06/30/2011
150369 7590 06/25/2018
Schwabe, Williamson & Wyatt/AMAT
1211 SW Fifth Ave.
Suite 1900
Portland, OR 97204
FIRST NAMED INVENTOR
XikunWANG
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
ATTORNEY DOCKET NO. CONFIRMATION NO.
15115/USA/ETCH/SILICON/MD 1290
EXAMINER
PHAM, THOMAS T
ART UNIT PAPER NUMBER
1713
NOTIFICATION DATE DELIVERY MODE
06/25/2018 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):
IPDocketing@SCHWABE.com
mscardina@schwabe.com
ghoover@schwabe.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte XIKUN WANG, ANDREW NGUYEN, CHANGHUN LEE,
XIAOMING HE, and MEIHUA SHEN
Appeal2017-007271
Application 13/174,090
Technology Center 1700
Before JAMES C. HOUSEL, JULIA HEANEY, and BRIAND. RANGE,
Administrative Patent Judges.
HOUSEL, Administrative Patent Judge.
DECISION ON APPEAL 1
Pursuant to 35 U.S.C. § 134(a), Appellants2 appeal from the
Examiner's decision rejecting claims 1-10 and 21-30. We have jurisdiction
over the appeal under 35 U.S.C. § 6(b).
We AFFIRM.
1 Our decision refers to the Specification (Spec.) filed June 30, 2011, the
Examiner's Final Office Action (Final Act.) dated April 26, 2016,
Appellants' Appeal Brief (Br.) filed September 26, 2016, and the
Examiner's Answer (Ans.) dated December 27, 2016.
2 According to Appellants, the real party in interest is Applied Materials, Inc.
Br. 3.
Appeal2017-007271
Application 13/174,090
STATEMENT OF THE CASE
The invention relates to in-situ cleaning and conditioning of plasma
processing chambers in the electronics manufacturing industry (Spec. i-f 2).
Appellants disclose that as feature sizes of microelectronic devices shrink,
elemental contamination originating from processing equipment, such as
those designed to perform plasma etching, becomes more detrimental to
device performance (id. i-f 3). To prevent plasma interaction with processing
chamber materials that might transfer contaminants to the workpiece,
Appellants disclose that a chamber coating comprising SiOx may be
deposited with a first plasma process onto a chamber surface prior to loading
the workpiece into the chamber to isolate them from the plasma (id. i-f 4, 7).
However, in order to reduce particulate defects from the coating shedding
onto the workpiece, Appellants provide an in-situ, low-pressure chamber
clean including an NF 3-based plasma to remove in-situ deposited Si Ox
coatings (id. i-f 6).
Claim 1, reproduced below from the Claims Appendix to the Appeal
Brief, is illustrative of the subject matter on appeal.
1. A plasma processing method comprising:
depositing, with a first plasma process that includes at
least a silicon-containing source gas combined with an
oxidizing source gas, and wherein no fluorine containing gas is
included in the first plasma process, a coating comprising SiOx
onto a chamber surface of a chamber, wherein xis greater than
zero;
etching a workpiece in the chamber with a second plasma
process, wherein the second plasma process is different than the
first plasma process;
removing the workpiece from the chamber; and
performing a clean of the chamber surface with a third
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plasma process after removing the workpiece, wherein the third
plasma process comprises a plasma clean utilizing a first
process gas including NF3.
Independent claim 21 similarly recites a plasma processing method,
wherein a process pressure of the first plasma process is less than that of the
second plasma process.
REJECTIONS
The Examiner maintains, and Appellants request our review of, the
following grounds of rejection:
1. Claims 1-10 and 21-30 under 35 U.S.C. § 112, first paragraph,
as failing to comply with the written description requirement;
2. Claims 1-7, 9, 10, 21-27, 29, and 30 under 35 U.S.C. § 103(a)
as unpatentable over Richardson 3 in view of Shen, 4 Mori, 5 Brand, 6
and Wang; 7 and
3. Claims 8 and 28 under 35 U.S.C. § 103(a) as unpatentable over
Richardson in view of Shen, Mori, Brand, and Wang, and further in
view of Baek. s, 9
3 Richardson et al., US 2006/0130873 Al, published June 22, 2006
("Richardson").
4 Shen et al., US 2008/0057729 Al, published March 6, 2008 ("Shen").
5 Mori et al., US 2008/0190893 Al, published August 14, 2008 ("Mori").
6 Brand, US 6,172,401 Bl, issued January 9, 2001.
7 Wang et al., US 2003/0173333 Al, published September 18, 2003
("Wang").
8 Baek et al., US 2008/0035170 Al, published February 14, 2008 ("Baek").
9 It appears that the Examiner inadvertently omitted Wang from this
rejection statement, since Wang is relied on to reject the claims from which
claims 8 and 28 depend. As will become clear later in this Decision, this
omission is harmless error.
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Application 13/174,090
Rejection 1
ANALYSIS
The Examiner rejects claims 1-10 and 21-30 under 35 U.S.C. § 112,
first paragraph, as failing to comply with the written description
requirement, on the basis that the limitation in claim 1, "wherein no fluorine
containing gas is included in the first plasma process," lacks support in the
Specification (Ans. 2). The Examiner notes the Specification discloses "a
silicon-containing source gas, such as but not limited to SiC14, is employed
with an oxidizing source gas, such as but not limited to 02 and N20" (id.,
quoting Spec. i-f 24). The Examiner finds that this disclosure not only does
not exclude a fluorine containing gas, but it also emphasizes that the silicon-
containing source gas is not limited to SiC14 (id.).
The Examiner further finds that one skilled in the art would recognize
that a fluorine-containing gas may be used to deposit a SiOx-based coating,
citing Abdelgadir10 for teaching a plasma process for silicon oxide
deposition, wherein oxygen reacts with SiF 4 to form Si02 (Ans. 8). The
Examiner finds that the skilled artisan would also recognize that just because
a gas is suitable for etching does not imply it cannot be used for deposition,
citing Nakaya 11 for teaching SiF 4 for plasma etching of silicon oxide (id.).
The Examiner additionally finds that the skilled artisan would further
recognize that deposition may occur during etching, citing Wang and Shen
for teaching deposition of a silicon oxide coating during etching of a silicon
substrate (id. at 8-9). Accordingly, the Examiner determines that the skilled
10 Abdelgadir et al., US 6,274,933 Bl, issued August 14, 2001
("Abdelgadir").
11 Nakaya, US 7,902,078 B2, issued March 8, 2011.
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artisan would not interpret the phrase, "[ f]luorine-based process gases are
well-suited for etching most inorganic chamber coatings, particularly the
exemplary SiOx-based coatings," from the Specification as implying that
fluorine-containing gas should be avoided when depositing the SiOx-based
coating of claims 1 and 21 (id. at 9).
Appellants argue that those skilled in the art would recognize that the
deposition process for producing the SiOx coating onto a chamber surface
utilizes a silicon-containing source gas, including SiC14 as one example of
such a gas (Br. 7-8). Appellants contend that when the Specification used
the phrase, "such as but not limited to," before listing SiC14, Appellants
allow for other silicon-containing source gasses known in the art that, with
an oxidizing source gas, form a SiOx coating (id. at 8). Appellants urge that
the Specification teaches that fluorine-based process gases are well-suited
for etching most inorganic chamber coatings, particularly SiOx-based
coatings, thereby teaching that the presence of a fluorine-based gas in the
first plasma process would result in removal of the Si Ox coating being
deposited (id.). As such, Appellants argue that the explicit teaching of the
etching effect of fluorine-based gases on Si Ox coatings conveys to those
skilled in the art that Appellants had possession of the limitation in question
(id.).
"[The written description] inquiry is a factual one and must be
assessed on a case-by-case basis." Purdue Pharma L.P. v. Paulding, Inc.,
230 F.3d 1320, 1323 (Fed. Cir. 2000). "In order to satisfy the written
description requirement, the disclosure as originally filed does not have to
provide in haec verba support for the claimed subject matter at issue." Id.
Nonetheless, the disclosure must convey with reasonable clarity to those
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skilled in the art that the Inventors were in possession of the invention as
claimed. Id., ("Put another way, one skilled in the art, reading the original
disclosure, must immediately discern the limitation at issue in the claims.").
Appearance of a claim in the Specification in ipsis verbis does not
guarantee that the written description requirement is satisfied, see, e.g., Enzo
Biochem, Inc. v. Gen-Probe Inc., 323 F.3d 956, 968 (Fed. Cir. 2002), nor
does a failure to meet that standard require a finding that a claim does not
comply with the written description requirement. In re Edwards, 568 F.2d
1349, 1351-52 (Fed. Cir. 1978). All that is required is that the Specification
demonstrate to a person of ordinary skill in the art that the Inventors were in
possession of the invention. Carnegie Mellon Univ. v. Hoffmann-La Roche
Inc., 541 F.3d 1115, 1122 (Fed. Cir. 2008).
Any negative limitation or exclusionary proviso must have basis in the
original disclosure. The mere absence of a positive recitation is not basis for
an exclusion. On the other hand, a lack of literal basis in the Specification
for a negative limitation may not be sufficient to establish a prima facie case
for lack of descriptive support. Ex parte Parks, 30 USPQ2d 1234, 1236
(BP AI 1993). If alternative elements are positively recited in the
Specification, they may be explicitly excluded in the claims. See In re
Johnson, 558 F.2d 1008, 1019 (CCPA 1977) ("[the] specification, having
described the whole, necessarily described the part remaining."); see also Ex
parte Grasselli, 231 USPQ 393 (BPAI 1983), aff'd mem., 738 F.2d 453 (Fed.
Cir. 1984). In describing alternative features, Appellants need not articulate
advantages or disadvantages of each feature in order to later exclude the
alternative features. See Inphi Corporation v. Netlist, Inc., 805 F.3d 1350,
1356-57 (Fed. Cir. 2015).
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Here, the limitation in question is a negative limitation, specifically
excluding fluorine containing gas in the first plasma process. We find that
the Specification discloses a first plasma process that deposits a SiOx coating
on a chamber surface, as well as a second different plasma process that
etches a workpiece in the chamber and a third plasma process utilizing NF 3
as a first process gas that cleans the chamber surface (Spec. i-fi-1 7, 8). In
addition, the Specification teaches that other fluorine-based gases, such as
SiF 6 and CF 4, may be used as the first process gas to clean the chamber
surface, and that fluorine-based process gases are well-suited for etching
most inorganic chamber coatings, including the SiOx coating deposited on
the chamber surface (id. i127). Thus, the Specification provides a reason to
exclude fluorine-based gases from the SiOx deposition process. See
Santarus, Inc. v Par Pharm., Inc., 694 F.3d 1344, 1351 (Fed. Cir. 2012).
Notwithstanding this reason to exclude, the Examiner finds that
Abdelgadir, Nakaya, Wang, and Shen are evidence that the ordinary artisan
would have understood that fluorine containing gases, while well-suited for
etching SiOx coatings, also form such coatings (Ans. 8, citing Abdelgadir,
Nakaya, Wang, and Shen). We note Abdelgadir teaches forming a
fluorosilicate glass layer, a silicon oxyfluoride (FxSiOy), via high-density
plasma chemical vapor deposition (HDP-CVD) by adding SiF 4 to silane
(SiH4), 0 2, and argon gases (Abdelgadir 2:6-19). Nakaya, Wang, and Shen
show redeposition of etched material removed during the etching process on
the sidewalls of a substrate or workpiece, but do not teach deposition of an
SiOx layer on a chamber surface in a first plasma process prior to a second
different plasma process for etching a workpiece in the chamber.
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Accordingly, the Examiner has not established by a preponderance of
the evidence that one skilled in the art would have understood that
Appellants were not in possession of the process of claims 1 and 21,
comprising the exclusion of fluorine-containing gases from the first plasma
process for depositing a SiOx layer on a chamber surface.
Rejection 2
The Examiner rejects claims 1-7, 9, 10, 21-27, 29, and 30 under 35
U.S.C. § 103(a) as unpatentable over Richardson in view of Shen, Mori,
Brand, and Wang. Appellants do not argue the claims separately, instead
focusing on the common limitations of claims 1 and 21 only. We, therefore,
select claim 1 in addressing the issues raised by Appellants' arguments.
Remaining claims 2-7, 9, 10, 21-27, 29, and 30 stand or fall with claim 1.
We review the appealed rejection for error based upon the issues
identified by Appellants and in light of the arguments and evidence
produced thereon. Ex parte Frye, 94 USPQ2d 1072, 107 5 (BP AI 2010)
(precedential) cited with approval in In re Jung, 637 F.3d 1356, 1365 (Fed.
Cir. 2011) ("[I]t has long been the Board's practice to require an applicant to
identify the alleged error in the examiner's rejections .... ")). After
considering the evidence presented in this Appeal and each of Appellants'
arguments, we are not persuaded that Appellants identify reversible error.
Thus, we affirm the Examiner's rejection for the reasons expressed in the
Answer. We add the following primarily for emphasis.
The Examiner finds Richardson teaches a plasma processing method
comprising etching a shallow trench isolation (STI) in a workpiece in a
plasma chamber with a first plasma process, followed by performing a
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wafer-less auto-clean (WAC) of the chamber surface with a second plasma
process after removing the workpiece using a NF3 source gas (Ans. 2-3).
The Examiner finds that Richardson is silent regarding the detail of the STI
etching (id. at 3). However, the Examiner finds that Shen teaches a method
for STI etching in a plasma chamber comprising plasma etching a silicon
substrate, which causes an overburden redeposition material on a wall of the
substrate, etching the redeposition material using a fluorine-containing gas,
forming an oxide layer on the substrate, and cyclically repeating the plasma
etching, redeposition etching, and oxide forming steps to incrementally etch
the silicon layer until the desired trench depth is reached (id. at 3--4).
As to the composition of the oxide layer, the Examiner finds that
although Shen is silent on its composition, Shen teaches that this layer is
formed by oxidation of a silicon substrate and, therefore, it is obvious that
this layer is silicon oxide (Ans. 4). Further, although Shen is silent as to
whether the etching of the redeposition material comprises a plasma, such
would have been obvious to use a plasma for this process because Shen
teaches use of the same fluorine-containing gases for this redeposition etch
as used in the substrate etch step (id.). The Examiner further finds that while
Shen's second plasma may include a fluorine-containing gas, other halogen-
containing gases are disclosed and an oxygen-containing gas may be
included (id. at 5).
The Examiner concludes that it would have been obvious, in routine
experimentation, to perform Richardson's STI etch using Shen's method,
given that Richardson fails to disclose the details of the STI etch and Shen
teaches an STI etch method that advantageously controls profile and
dimension features (Ans. 4). The Examiner then finds that the resulting
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modified method of Richardson would comprise, sequentially, loading a first
substrate, etching the substrate with a first plasma that forms a redeposition
material, etching the same substrate with a second plasma to remove the
redeposition material, forming the oxidation layer, etching the substrate
using a third plasma that forms a second redeposition material, cyclically
repeating these steps until the desired trench depth is reached, removing the
substrate from the plasma chamber, performing WAC with the fourth
plasma, and repeating these steps for a plurality of substrates (id.).
The Examiner finds that the first plasma, in the first cycle, is
equivalent to the first plasma process of claims 1 and 21 (Ans. 5). The
Examiner next finds that the second and fourth plasmas are equivalent to the
second and third plasma processes, respectively, of claims 1 and 21 (id.).
The Examiner notes that because claims 1 and 21 do not require the SiOx-
based coating be on the chamber surface during the etching step with the
second plasma, the second and third plasmas in the first or any subsequent
cycles may be considered the second plasma process of claims 1 and 21
(id.). Alternatively, the Examiner finds that the third plasma may be
considered the first plasma process, and either the second or third plasma in
subsequent cycles may be considered the second plasma process, of claims 1
and 21 (id.). Further, the Examiner finds that because the third plasma
etches the substrate and redeposits material and is used in separate cycles,
the third plasma in separate cycles is different (id.).
With regard to the use of a silicon-containing source gas and an
oxidizing source gas as the first plasma, the Examiner finds Mori teaches a
method of forming a deep trench in a silicon substrate using a plasma
comprising a gas such as SiF 4 or SiC14 mixed with oxygen to form highly
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accurate trenches with no bowing (Ans. 5). The Examiner also finds Brand
teaches forming an STI by etching a silicon substrate using a gas comprising
H2/Cb/SiC14 (id.). The Examiner concludes, therefore, that it would have
been obvious to use a SiCl4/02 mixture in the first and third plasmas in
Shen's STI etching process because Shen teaches the plasma comprises a
halogen-containing gas and a silicon-containing gas, Mori teaches such a
SiCl4/02 mixture forms highly accurate trenches with no bowing, and Brand
teaches use of SiC14 for STI etching (id. at 5---6).
With regard to the step of deposition of a Si Ox coating on a surface of
the chamber, the Examiner finds that because of Shen's use of a substrate
bias power up to 300 W, "some silicon oxide material inevitably is sputtered
off the silicon oxide layer (layer 508 in Fig. 5C that is formed in step 206)
during the plasma etching in step 204 or step 208, and deposit[ s] on the
chamber surface" (Ans. 6). In addition, the Examiner finds that a plasma of
SiCl4 and 02 would also inevitably comprise silicon and oxygen ions, that
the etching of the silicon oxide in steps 204 and 208 of Shen inevitably
produces silicon and oxygen ions in the plasma, and that these ions
inevitably react with each other and form SiOx molecules, at least some of
which deposit on the chamber surface exposed to the plasma, which the
Examiner finds is confirmed by Wang (id.).
Appellants argue that Shen's etching process does not include the
deposition of a coating on a chamber surface as recited in claims 1 and 21
(Br. 11 ). In particular, Appellants contend that Shen removes the
redeposition layer from the substrate at step 205 using a cleaning etch
operation (id.). As such, according to Appellants, Shen removes the
redeposition material each time it is formed (id.).
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Appellants further argue that, because there would not be any silicon-
based residues on the chamber surfaces during formation of the oxidation
layer in Shen's process, the Examiner's finding that the formation of the
oxidation layer would inevitably form some SiOx on the chamber surface is
incorrect (Br. 12). Appellants assert that removal of redeposition material in
step 205 would remove any silicon containing substance from the chamber
surfaces, thereby preventing formation of a SiOx coating thereon (id.). In
addition, Appellants contend that Shen fails to describe the formation of the
oxidation layer as a plasma process as required by claims 1 and 21 (id. at
12-13). Appellants urge that Shen forms the oxide layer simply by exposing
the substrate to an oxygen-containing gas without the need for a plasma (id.
at 130). Finally, Appellants argue that Wang's etching process requires the
presence of fluorine, which is excluded from the first plasma process of
claims 1 and 21 (Br. 13-14).
Appellants' arguments are not persuasive of reversible error.
Appellants state their understanding of the rejection is that the Examiner
considers STI etching residue or redeposition material to be equivalent to the
recited Si Ox coating deposited in the first plasma process of claims 1 and 21
(Br. 9). Appellants further state they understand the Examiner suggests that
a coating is formed on the walls of the chamber during the etching steps and
during formation of the oxidation layer based on the Examiner's finding
that, since the walls of the chamber are exposed to the plasma, deposition of
etching residue or redeposition material thereon would be inevitable (id. at
10). We note Appellants do not challenge the Examiner's findings that
Shen's process inevitably or inherently forms SiOx coatings on a chamber
surface during the etching steps 204 and 208. We further note that although
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Appellants argue that Shen repeatedly removes these coatings in step 205,
Appellants fail to argue or explain the significance of this point. As the
Examiner notes (Ans. 10), claims 1 and 21 do not require that the coating be
present during the etching step or, indeed, during any other step. Thus,
claims 1 and 21 do not exclude the removal of the Si Ox coating each time it
is formed as would be the case in Shen's process.
Further, while Appellants appear to be correct that Shen's oxidation
step would not form a SiOx coating on the chamber surface because the
redeposition cleaning step would have been expected to have removed any
silicon present thereon, the Examiner states that it is the redeposition
material formed in steps 204 and 208, and not the oxidation step 206, that
correspond to the deposition of a Si Ox coating on the chamber surface (Ans.
9--10).
Finally, as to Appellants' argument that Wang's etching process
requires the presence of fluorine, we note the Examiner relies on Mori and
Brand as teaching that the use of a silicon-containing source gas such as
SiCl4 and an oxidizing gas, without the inclusion of a fluorine-containing
gas, was known for etching STI structures in silicon substrates. Appellants
fail to respond to or otherwise address the Examiner's findings with regard
to Mori and Brand. Moreover, Wang clearly discloses the use of plasma
etching gases, many of which do not include fluorine (Wang i-f 37), thereby
supporting the Examiner's position.
Accordingly, for the reasons given in the Examiner's Answer and
above, we sustain the Examiner's obviousness rejection of claims 1-7, 9, 10,
21-27, 29, and 30.
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Rejection 3
The Examiner rejects claims 8 and 28 under 35 U.S.C. § 103(a) as
unpatentable over Richardson in view of Shen, Mori, Brand, and Wang, and
further in view of Baek. Appellants do not challenge or otherwise address
this rejection, instead relying on the arguments raised against independent
claims 1 and 21. Because those arguments are not persuasive as discussed
above, we likewise sustain this rejection.
DECISION
Upon consideration of the record, and for the reasons given above and
in the Appeal Brief, the decision of the Examiner rejecting claims 1-10 and
21-30 under 35 U.S.C. § 112, first paragraph, for lack of an adequate written
description is reversed.
However, for the reasons given above and in the Examiner's Answer,
the decision of the Examiner rejecting claims 1-7, 9, 10, 21-27, 29, and 30
as unpatentable over the combination of Richardson, Shen, Mori, Brand, and
Wang, and rejecting claims 8 and 28 over this combination further in view
of Baek, 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)(l ).
AFFIRMED
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