Ex Parte Zhou et al

Patent Trial and Appeal Board

Sep 6, 2018

14582089 (P.T.A.B. Sep. 6, 2018)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR
14/582,089 12/23/2014 Feng Zhou
107446 7590 09/10/2018
DLA Piper LLP (US)
2000 University A venue
East Palo Alto, CA 94303-2248
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.
351913-998810 6843
EXAMINER
BERMUDEZ LOZADA, ALFREDO
ART UNIT PAPER NUMBER
2825
NOTIFICATION DATE DELIVERY MODE
09/10/2018 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):
patentdocketingus-paloalto@dlapiper.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte FENG ZHOU, XIAN LIU, NHAN DO,
RIEU VAN TRAN, and HUNG QUOC NGUYEN
Appeal2018-000684
Application 14/582,089
Technology Center 2800
Before BRADLEY R. GARRIS, JAMES C. HOUSEL, and
MONTE T. SQUIRE, Administrative Patent Judges.
HOUSEL, Administrative Patent Judge.
DECISION ON APPEAL 1
Pursuant to 35 U.S.C. § 134(a), Appellant2 appeals from the
Examiner's decision finally rejecting claims 1-18. We have jurisdiction
over the appeal under 35 U.S.C. § 6(b ).
We AFFIRM.
1 Our decision refers to the Specification (Spec.) filed December 23, 2014,
the Examiner's Final Office Action (Final) dated November 1, 2016,
Appellant's Appeal Brief (Appeal Br.) filed April 27, 2017, the Examiner's
Answer (Ans.) dated August 25, 2017, and Appellant's Reply Brief (Reply
Br.) filed October 25, 2017.
2 Appellant is the Applicant, Silicon Storage Technology, Inc., which is
identified in the Appeal Brief as the real party in interest (Appeal Br. 2).
Appeal2018-000684
Application 14/582,089
STATEMENT OF THE CASE
The invention relates to a resistive random access memory (RRAM)
(Spec. ,r 1 ). Appellant discloses that a conventional RRAM includes a
resistive dielectric material layer sandwiched between two of conductive
material electrode layers (id. ,r 3; Fig. 1 ). In its initial state following
fabrication, the RRAM exhibits a relatively high resistance. However, by
applying an appropriate voltage across the dielectric layer, a conductive
filament forms through the dielectric layer such that the layer exhibits a
relatively low resistance because of the relatively high conductivity of the
filament. The filament can be ruptured or broken by applying a reset voltage
across the dielectric layer creating a relatively high resistance in the area of
the rupture or break. The filament can be restored in the area of the rupture
by applying a set voltage across the dielectric layer such that a relatively low
resistance is restored. In use, the RRAM can provide a digital signal state,
e.g., "1 ", when the resistance is low and a digital signal state, e.g., "O", when
the resistance is high. See Spec. ,r 4; Figs. 2A-2D. Appellant discloses that
a drawback of such RRAM's is that the voltage and current needed to form
the conductive filament are relatively high (Spec. ,r 5). Appellant, therefore,
teaches one solution to reduce the voltage and current needed to form the
conductive filament is to form a transition metal oxide layer between two
conductive electrode layers such that the transition metal oxide layer
includes first and second elongated portions meeting each other at a sharp
comer (id. ,r 6).
Claim 1, reproduced below from the Claims Appendix to the Appeal
Brief, is illustrative of the subject matter on appeal. The limitations at issue
are italicized.
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Application 14/582,089
1. A memory device, comprising:
a first electrode of conductive material;
a second electrode of conductive material;
a layer of transition metal oxide material that includes first
and second elongated portions meeting each other at a sharp
corner, wherein each of the first and second elongated portions
includes elongated opposing first and second surfaces and is
disposed between and in electrical contact with the first and
second electrodes such that:
a portion of the first surface of the first elongated
portion beginning at and extending away from the sharp
comer is in continuous direct electrical and physical
contact with the first electrode and a portion of the second
surface of the first elongated portion beginning at and
extending away from the sharp comer is in continuous
direct electrical and physical contact with the second
electrode, and
a portion of the first surface of the second elongated
portion beginning at and extending away from the sharp
comer is in continuous direct electrical and physical
contact with the first electrode and a portion of the second
surface of the second elongated portion beginning at and
extending away from the sharp comer is in continuous
direct electrical and physical contact with the second
electrode.
REJECTIONS
The Examiner maintains, and Appellant requests our review of, the
following grounds of rejection:
1. Claims 1--4 and 7-11 under 35 U.S.C. § I02(a)(l) as
anticipated by Ozawa; 3
3 Ozawa et al., US 2011/0140068 Al, published June 16, 2011 ("Ozawa").
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2. Claims 5 and 12 under 35 U.S.C. § 103 as unpatentable over
Ozawa in view ofTu; 4
3. Claims 6 and 13 under 35 U.S.C. § 103 as unpatentable over
Ozawa in view of Lung; 5
4. Claims 14--17 under 35 U.S.C. § 103 as unpatentable over
Ozawa in view ofToda; 6 and
5. Claim 18 under 35 U.S.C. § 103 as unpatentable over Ozawa in
view of Toda, and further in view of Tu.
ANALYSIS
Rejection 1
The dispositive issue before us in this appeal is whether Appellant has
identified reversible error in the Examiner's finding that Ozawa teaches a
layer of transition metal oxide material which includes layers 14, 15 as well
as layer 13, such that the layer of transition metal oxide material is in
continuous direct electrical and physical contact with both electrodes. For
substantially the findings of fact and reasoning given in the Final Office
Action and the Examiner's Answer, we answer this question in the negative
and sustain the Examiner's anticipation rejection based on Ozawa. We offer
the following for emphasis only.
The Examiner rejects claims 1--4 and 7-11 under 35 U.S.C.
§ I02(a)(l) as anticipated by Ozawa (Final 2---6). Appellant does not argue
the claims separately, but instead presents arguments directed to independent
4 Tu et al., US 2014/0131654 Al, published May 15, 2014 ("Tu").
5 Lung et al., US 2011/0278528 Al, published November 17, 2011
("Lung").
6 Toda, US 2013/0170280 Al, published July 4, 2013.
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Application 14/582,089
claims 1 and 7. Dependent claims 2--4 and 8-11 stand or fall with respective
independent claims 1 and 7. 37 C.F.R. § 4I.37(c)(l)(iv).
The Examiner finds that Ozawa teaches an RRAM having a layer of
transition metal oxide material including first and second elongated portions
meeting each other at a sharp comer wherein each portion is disposed
between and in electrical contact with first and second electrodes and each
portion includes opposing first and second surfaces, such that a portion of
the first surface of each of the first and second elongated portions is in
continuous direct electrical and physical contact with the first electrode and
a portion of the second surface of each of the first and second elongated
portions is in continuous direct electrical and physical contact with the
second electrode (id. at 2--4). In particular, the Examiner interprets Ozawa's
layers 13, 14, and 15 as the layer of transition metal oxide material (id. at 3).
Appellant argues that although Ozawa does indeed disclose layer of
transition metal oxide material 13 disposed between electrodes 11 and 12,
conductive layer 14 and rectifying insulating film 15 are disposed between
layer 13 and electrode 12 such that layer 13 is not in continuous direct
electrical and physical contact with electrode 12 as recited in claim 1
(Appeal Br. 10-11). Appellant contends that it is only by considering
Ozawa's layers 13, 14, 15 collectively as the layer of transition metal oxide
material that the Examiner finds continuous direct electrical and physical
contact for both Ozawa's electrodes 11, 12 (id. at 11). However, Appellant
contends there is no basis to consider Ozawa's layers 14, 15 as part of the
transition metal oxide material layer 13 (id. at 12).
Appellant urges that Ozawa discloses that rectifying insulating film
relies on the tunneling effect to control the passage of current, thereby
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Application 14/582,089
allowing for larger electrical currents to be supplied to layer 13 for enhanced
switching yield (Appeal Br. 12). As such, Appellant argues that Ozawa
teaches away from the present invention which uses continuous direct
electrical and physical contact with both electrodes around a sharp comer to
minimize voltages and currents supplied to the transition metal oxide layer
for reliable switching yield (id.). Appellant contends that Ozawa's layers 14
and 15 are not themselves transition metal oxide material nor do they
participate in or undergo any state transition, i.e., resistance that can be
reversibly changed (id.).
As to the Examiner's interpretation ofOzawa's layers 13, 14, 15 as
being the layer of transition metal oxide material, Appellant urges that the
broadest reasonable construction of "transition metal oxide material" is "a
layer containing both metal and oxide, and is capable of transition between
conductive states" (Appeal Br. 12). Because Ozawa's layers 14 and 15 are
not described as containing both a metal and an oxide and participating in or
capable of undergoing a conductive state transition, Appellant argues that
these layers are not the layer of transition metal oxide material (id.).
Appellant urges that the Examiner's inclusion of layers 14 and 15 as part of
the transition metal oxide layer is arbitrary and without support (id.).
These arguments are not persuasive of reversible error. Appellant's
arguments interpret the "layer of transition metal oxide material" so as to
exclude a multi-layer structure containing sub-layers of other materials along
with a sub-layer of transition metal oxide material. However, as the
Examiner finds (Ans. 6), Appellant discloses that the "resistive dielectric
layer 12 is made of a transition metal oxide ... or multiple layers of such
materials, etc." (Spec. ,r 23). Appellant further discloses that the "resistive
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dielectric layer 12 can be a composite of discrete sub-layers with one or
more sub-layers of transition metal oxides (e.g. layer 12 could be multiple
layers: a Hf layer disposed between a TaOx layer and a HfOx layer)" (id.).
Importantly, this last example of a resistive dielectric layer is a multi-layer
structure including a non-transition metal oxide layer, i.e., a Hf layer, that
itself would not undergo a conductive state change. Thus, when interpreted
in light of Appellant's Specification, the recited "layer of transition metal
oxide material" reasonably encompasses a multi-layer structure including at
least one sub-layer of transition metal oxide.
Although Appellant argues that "the layer of transition metal oxide
only includes those layers or materials involved in the transition of
conductive state" (Reply Br. 5---6), claims 1 and 7 do not include such a
limitation. In re Self, 671 F.2d 1344, 1348 (CCPA 1982) ("Many of
appellant's arguments fail from the outset because, as the solicitor has
pointed out, they are not based on limitations appearing in the claims.").
Further, Appellant fails to direct our attention to any disclosure limiting the
resistive dielectric layer to a single layer consisting of or comprising
transition metal oxide or multiple layers consisting of sub-layers of
transition metal oxide only. Nor does Appellant direct our attention to any
disclosure requiring that the entirety of the layer of transition metal oxide
material participate in the conductive state transition. Instead, all that is
necessary is that this layer is capable of conductive state transition. Because
Ozawa includes a variable resistance film 13 made of transition metal oxide
that undergoes a conductive state transition (Ozawa ,r 37), Ozawa's variable
resistance film 13, conductive layer 14, and rectifying insulating film 15,
when considered together as a layer of transition metal oxide material,
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consistent with Appellant's Specification, are capable of undergoing
conductive state transition.
Finally, as the Examiner correctly determines (Ans. 7-8), Appellant's
teaching away argument is not relevant to the propriety of the Examiner's
anticipation rejection. In re Malagari, 499 F.2d 1297, 1302 (CCPA 1974)
("If the rejection under § 102 is proper ... appellant cannot overcome it by
showing such unexpected results or teaching away in the art, which are
relevant only to an obviousness rejection.").
Accordingly, we affirm the Examiner's anticipation rejection of
claims 1--4 and 7-11 based on Ozawa.
Rejections 2-4
Appellant relies on the arguments presented above with regard to
Rejection 1, and further contend that none of the secondary references cure
the alleged deficiencies of Ozawa. However, as set forth above, because we
are not persuaded that Ozawa is deficient with regard to the anticipation
rejection of claims 1 and 7, we affirm each of the Examiner's obviousness
rejections.
DECISION
Upon consideration of the record, and for the reasons given above and
in the Examiner's Answer and Final Office Action, the decision of the
Examiner rejecting claims 1-18 is affirmed.
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No time period for taking any subsequent action in connection with
this appeal maybe extended under 37 C.F.R. § 1.I36(a)(l).
AFFIRMED
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