Ex Parte Kameda et al

Patent Trial and Appeal Board

Jun 15, 2017

12379471 (P.T.A.B. Jun. 15, 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.
12/379,471 02/23/2009 Kenji Kameda 139679.01 6816
759025944
OLIFF PLC
P.O. BOX 320850
ALEXANDRIA, VA 22320-4850
06/19/2017 EXAMINER
MARKOFF, ALEXANDER
ART UNIT PAPER NUMBER
1711
NOTIFICATION DATE DELIVERY MODE
06/19/2017 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):
OfficeAction25944@oliff.com
j armstrong @ oliff.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE
THE PATENT TRIAL AND APPEAL BOARD
Ex parte KENJI KAMEDA,1
Jie Wang, and Yuji Urano
Appeal 2016-0006082
Application 12/379,471
Technology Center 1700
Before MARKNAGUMO, KAREN M. HASTINGS, and
JENNIFER R. GUPTA, Administrative Patent Judges.
NAGUMO, Administrative Patent Judge.
DECISION ON APPEAL
Kenji Kameda, Jie Wang, and Yuji Urano (“Hitachi”) timely appeal
under 35 U.S.C. § 134(a) from the Final Rejection3 of all pending claims 1-
5, 7-9 and 11-21. We have jurisdiction. 35 U.S.C. § 6. We reverse.
1 The real party in interest is identified as Hitachi Kokusai Electric Inc.
(“Hitachi”). (Appeal Brief, filed 12 February 2015 (“Br.”), 1.)
2 Heard 13 June 2017. The Official Transcript, which was not available
when this Opinion was entered, will be made of record.
3 Office Action mailed 13 August 2014 (“Final Rejection”; cited as “FR”),
as modified by the Advisory Action entered 22 October 2014, entering an
amendment cancelling claim 22.
Appeal 2016-000608
Application 12/379,471
OPINION
A. Introduction4
The subject matter on appeal relates to a method of manufacturing
semiconductor devices (independent claim 1) in which a silicon nitride
(Si3N4, hereinafter, “SiN”) film built up on the interior surfaces of the
processing chamber and on internal members, such as a boat holding
multiple substrates, is removed efficiently. The ’471 Specification explains
that SiN, deposited by chemical vapor deposition methods on substrate
wafers, also builds up on the interior surfaces of the processing chamber and
on the exposed internal members. At some thickness, the film begins to peel
off, leading to particles in the processing chamber. (Spec. 1 [0002].) The
inventors found that particles are produced profusely under standard
processing conditions at film thicknesses of about 2 pm, corresponding to
about 12 runs of SiN film formation. {Id. at 38-39 [0101], discussing
Fig. 8.) Thus, frequent cleaning or removal of the SiN film is necessary.
The Specification teaches that prior art methods of removing the SiN
film involve the use of hydrogen fluoride (HF) gas. {Id. at 2 [0003].)
Although HF removes the SiN film, it tends to corrode exposed metal
surfaces in the processing chamber and to erode quartz members such as the
“boats” that hold the wafer substrates being processed in the chamber.
{Id. at [0004].) Moreover, immediately after cleaning with HF, decreased
4 Application 12/379,471, Method for manufacturing semiconductor device
and substrate processing apparatus, filed 23 February 2009 as a division of
12/292,995, filed 2 December 2008, now abandoned, claiming the benefit of
three applications filed in Japan on 5 Dec 2007, 27 Feb 2008, and
on 8 Oct 2008. We refer to the “’471 Specification,” cited as “Spec.”
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Application 12/379,471
film formation rates are often observed. (Id.) (In the words of the
Specification, “[t]he decreased film formation rates is presumed to be caused
by an increased effective surface area of the surfaces of quartz members (the
reaction tube 103[5] and the boat 102). . . due to cracks on the surfaces of the
quartz members because of cumulative film formations.” (Id. at 9 [0018].))
Hitachi seeks patent protection for methods and apparatuses that avoid
these problems, i.e., that suppress the corrosion of the metal and the
degradation of the quartz, and yet can be conducted with minimal down time
and interruption of the wafer-processing. These goals are said to be obtained
by unloading the processed substrates from the processing chamber,
returning the boat to the chamber (still at the processing temperature), and
then force-cooling the chamber rapidly enough to generate cracks in the SiN
film. The SiN film is then removed by introducing fluorine gas, without any
hydrogen-containing gas (especially HF), to the processing chamber at a first
temperature. Then, at a second temperature between 450°C and 500°C, the
surface of the quartz member is smoothened by supplying fluorine gas, again
without any hydrogen-containing gas, to the inside of the processing
chamber. This “smoothening” is said to remove adhered materials such as
minute quartz powders generated due to quartz cracks, as well as removing
the quartz cracks themselves. (Id. at 23 [0054].)
Again, the disclosed process is said to suppress corrosion of the
exposed metal and breakage of the quartz members. Moreover, the forced
cooling can be conducted rapidly, so the down time due to cleaning is
5 Throughout this Opinion, for clarity, labels to elements are presented in
bold font, regardless of their presentation in the original document.
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Application 12/379,471
diminished, and the decreased film formation is also suppressed on the
subsequent SiN film formation runs, also leading to more efficient
operations. {Id. at 5 [0009].)
Claim 1 is representative and reads:
A method for manufacturing a semiconductor device
comprising:
loading a substrate into a processing chamber in which a
quartz member and a metal member are contained;
performing a processing of forming a silicon nitride film on
the substrate by supplying a processing gas into the
processing chamber heated to a processing temperature by a
heater provided outside of the processing chamber;
unloading the processed substrate out of the processing
chamber;
after the forming of the silicon nitride film,
[1] purging an inside of the processing chamber with a gas
while
applying a thermal impact to the silicon nitride film
deposited on a surface of the quartz member in the
processing chamber
by decreasing a temperature in the processing
chamber to a temperature lower than the processing
temperature, so as to forcibly generate a crack in the
silicon nitride film,
in a state where the substrate is not present in the
processing chamber,
[3] wherein the decreasing of the temperature in the
processing chamber to the temperature lower than the
processing temperature is performed by
a forced-cooling mechanism outside of the
processing chamber,
the forced-cooling mechanism being oriented to
cover the processing chamber and the heater by
means of a heat insulation cover;
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Application 12/379,471
at a time point when a thickness of the silicon nitride film
accumulated on the surface of the quartz member in the
processing chamber reaches a predetermined thickness
before the silicon nitride film starts peeling off or dropping,
[2] removing the silicon nitride film deposited on the
surface of the quartz member in the processing chamber by
thermo-chemical reaction, by
supplying a fluorine gas solely or a fluorine gas diluted
by an inert gas solely without supplying a hydrogen-
containing gas to the inside of the processing chamber
heated to a first temperature,
in the state where the substrate is not present in the
processing chamber; and
after the removing of the silicon nitride film,
[2'] smoothening the surface of the quartz member by
etching the surface of the quartz member by
supplying the fluorine gas solely or the fluorine gas
diluted by the inert gas solely without supplying the
hydrogen-containing gas to the inside of the processing
chamber
heated to a second temperature, by the heater,
in the state where the substrate is not present in the
processing chamber,
[4] wherein the second temperature is set to
not less than 450°C and not more than 500°C, and
wherein corrosion of the metal member and breakage of the
quartz member are suppressed.
(Claims App., Br. Al-2; some indentation, paragraphing, emphasis, and
bracketed labels6 to argued features added.)
Claim 2 depends from claim 1 and requires that a cooling medium
flow outside of the processing chamber in the purging step [1].
6 We generally follow the labels used by Hitachi in the Brief. (Br. 10.)
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Application 12/379,471
Independent claims 7 and 8 cover a corresponding apparatus, and
remaining independent claim 19 covers a method of operating the apparatus.
The Examiner maintains the following grounds of rejection7’8’9:
A. Claims 1-5, 7-9 and 11-21 stand rejected under
35 U.S.C. § 103(a) in view of the combined teachings of
Hasebe10 and Okada.* 11
Al. Claims 1-5, 7-9 and 11-21 stand rejected under
35 U.S.C. § 103(a) in view of the combined teachings of
Hasebe, Nodera,12 and Okada.
7 Examiner’s Answer mailed 13 August 2015 (“Ans.”).
8 Because this application was filed before the 16 March 2013 effective date
of the America Invents Act, we refer to the pre-AIA version of the statute.
9 The amendment under 37 C.F.R. § 1.116 filed 14 October 2014,
cancelling claim 22, was entered (Advisory Action 22 October 2014),
removing all rejections of claim 22.
10 Kazuhide Hasebe and Mitsuhiro Okada, Film forming method, film
forming system and recording medium, U.S. Patent Application Publication
2006/0141782 Al (2006), now U.S. Patent No. 7,416,978 (26 August 2008).
11 Mitsuhiro Okada et al., Film formation apparatus and method of using the
same, U.S. Patent Application Publication 2006/0068598 Al (2006), now
U.S. Patent No. 7,470,637 (30 December 2008).
12 Nobutake Nodera et al., Film formation apparatus and method for using
same, U.S. Patent Application Publication 2009/0117743 Al (2009), based
on an application filed 7 October 2008; now U.S. Patent No. 8,080,477
(20 December 2011).
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Application 12/379,471
B. Discussion
The Board’s findings of fact throughout this Opinion are supported by
a preponderance of the evidence of record.
Hitachi’s arguments for patentability focus on limitations recited in
claim 1, to which we direct our attention primarily.
Briefly, the Examiner finds that Hasebe describes a processing
apparatus and method that carries out the claimed process but for the SiN
removal [2] and smoothening [2'] steps. (FR 3—4.) The Examiner finds that
Okada describes such steps in a similar process, and concludes that it would
have been obvious to modify the process described by Hasebe by adding the
cleaning and planarizing steps taught by Okada. {Id. at 4-5.) The Examiner
also finds thatNodera discloses similar deposition and cleaning steps, and
concludes that the claimed process would have been obvious in view of the
combined teachings of all three references. {Id. at 8-10.)
Initially, we reject Hitachi’s arguments (Br. 11-13; Reply131 ^4) that
the Examiner erred in finding motivation to combine the cleaning and
planarizing teachings of Okada with the SiN cracking and purging step
taught by Hasebe. Hasebe is concerned with improving a prior art process
by providing more “recipes” for purging. Hitachi does not direct our
attention to any credible evidence that Hasebe teaches that steps to remove
SiN films and steps to planarize the substrates should not be conducted.
Hitachi argues further that Hasebe does not teach the forced cooling required
by feature [3] of claim 1 because “Hasebe’s portion 52, alleged to be the
13 Reply Brief filed 13 October 2015 (“Reply”).
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Application 12/379,471
cooling mechanism, is disclosed as a heating furnace provided with
heater 51.” (Br. 16, 4th para.; Reply 6, 1st full para.) This argument gives
insufficient weight to the Examiner’s finding that “[t]he cooling mechanism
comprises cover (52) and cooler g[as] means (58, 56, 54, 55, and 57). All of
these parts are located outside of the chamber (2).” (FR 12, last sentence;
see also Ans. 21, last para., through 22.) Hitachi also argues that “the
cooling mechanism is recited to cover both the processing chamber and the
heater.” (Br. 16, last para.) Claim 1, however, recited that this occurs “by
means of a heat insulation cover.” Although the nature of the wall of
furnace 52, indicated by slanted lines in Hasebe Figure 1, does not appear to
be specified, we do not find credible an argument that it is not—or that it
would not have been obvious—to provide that wall as an insulating wall for
thermal efficiency and safety. (Cf. FR 12; Ans. 21-22.)
However, as Hitachi urges (Br. 14-15; Reply 4-6), the critical flaw in
the Examiner’s findings is that Okada does not teach or suggest planarizing
gases that do not contain hydrogen fluoride. On the contrary, Okada teaches
that, “[a]s shown in FIG. 5D, where the planarizing gas did not contain
hydrogen fluoride, quartz cracks were essentially not removed.
Accordingly, it has been confirmed that the planarizing gas needs to contain
hydrogen fluoride.” (Okada 6 [0092]; italics added.)
The Examiner offers several responses, the first three of which (that
the claims do not exclude the planarizing steps as disclosed by Okada; that
claim 1 does not require that the removing and smoothening steps be
conducted at different temperatures; and that Hasebe cures any deficiencies
of Okada regarding the proper temperature of reaction with fluorine
(Ans. 19-20)) are not persuasive because they do not address the limitation
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Application 12/379,471
that the step of planarization is required to be conducted without supplying a
hydrogen-containing gas to the inside of the chamber. The Examiner’s final
argument, that the claims do not require removing of cracks, but only an
unspecified amount of smoothing {id. at 20), is not well-taken in view of
Okada’s teaching that “it has been confirmed that the planarizing gas needs
to contain hydrogen fluoride.” (Okada 6 [0092].) Disclosures are presumed
to be directed to persons having ordinary skill in the art. The Examiner has
not directed our attention to any credible evidence that such persons would
have understood the term “smoothening,” as used by Hitachi, or the term
“planarizing,” as used by Okada, to have such broad meanings that they
would include only minute removal of cracks.
A rejection for obviousness fails if any limitation is not accounted for
properly. Both of the Examiner’s obviousness rejections rely on erroneous
findings regarding Okada discussed above. Accordingly, we reverse both
obviousness rejections.
C. Order
It is ORDERED that the rejections of claims 1-5, 7-9 and 11-21 are
reversed.
REVERSED
9