Ex Parte Zhu et al

Patent Trial and Appeal Board

Apr 26, 2017

14077093 (P.T.A.B. Apr. 26, 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.
14/077,093 11/11/2013 Xiaochun Zhu QCOM-2282US (133249) 5049
112246 7590 04/28/2017
Loza & Loza, LLP/Qualcomm
305 N. Second Ave., #127
Upland, CA 91786
EXAMINER
JEUDY, JOSNEL
ART UNIT PAPER NUMBER
2438
NOTIFICATION DATE DELIVERY MODE
04/28/2017 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):
ocpat_uspto@qualcomm.com
qualcomm-pto@lozaip.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte XIAOCHUN ZHU, STEVEN M. MILLENDORF, XU GUO,
DAVID MERRILL JACOBSON, KANGHO LEE, SEUNG H. KANG, and
MATTHEW MICHAEL NOWAK
Appeal 2017-000529
Application 14/077,093
Technology Center 2400
Before KRISTEN L. DROESCH, CATHERINE SHIANG, and
MELISSA A. HAAPALA, Administrative Patent Judges.
SHIANG, Administrative Patent Judge.
DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134(a) from the Examiner’s
rejection of claims 1—30, which are all the claims pending and rejected in the
application. We have jurisdiction under 35 U.S.C. § 6(b). We affirm-in-
part.
STATEMENT OF THE CASE
Introduction
According to the Specification, the present invention relates to
physically unclonable functions. See generally Spec. 1. Claim 1 is
exemplary:
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Application 14/077,093
1. A method for implementing a physically unclonable function (PUF)
using an array of magnetoresistive random-access memory (MRAM) cells
having magnetic tunnel junctions with randomly-varying resistances,
comprising:
issuing a challenge by applying a physically unclonable function
(PUF) challenge signal to a particular array of magnetoresistive random-
access memory (MRAM) cells having a plurality of magnetic tunnel
junctions, the challenge signal specifying a plurality of MRAM cell
addresses of at least some of the magnetic tunnel junctions of the particular
array; and
obtaining a physically unclonable function (PUF) response to the
challenge by ascertaining a resistance of the magnetic tunnel junctions of the
plurality of MRAM cell addresses of the particular array to generate a
physically unclonable function (PUF) signal representative of at least a
partial map of the particular array that identifies the particular array and
distinguishes the particular array from other similar arrays.
References and Rejections
Claims 1—9, 11—14, and 16—29 are rejected under 35 U.S.C. § 103 as
being unpatentable over Sakata (US Patent Publication No. 2004/0042292
Al; published Mar. 4, 2004) and Christensen (US Patent Publication No.
2012/0106235 Al; published May 3, 2012).
Claims 10, 15, and 30 are rejected under 35 U.S.C. § 103 as being
unpatentable over Sakata, Christensen, and Chen (US Patent Publication No.
2006/0265733 Al; published Nov. 23, 2006).
ANALYSIS1
On this record, the Examiner did not err in rejecting claim 1.
1 To the extent Appellants advance new arguments in the Reply Brief
without showing good cause, Appellants have waived such arguments. See
37 C.F.R. §41.41 (b)(2).
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We agree with and adopt the Examiner’s findings and conclusions in
(i) the action from which this appeal is taken and (ii) the Answer to the
extent they are consistent with our analysis below.
Appellants contend there is no reasonable independent motivation to
combine the references as proposed by the Examiner. See App. Br. 11—13;
Reply Br. 1—3.
Appellants have not persuaded us of error. The U.S. Supreme Court
has held “[t]he combination of familiar elements according to known
methods is likely to be obvious when it does no more than yield predictable
results.” KSR Inti Co. v. Teleflex, Inc., 550 U.S. 398, 416 (2007). Contrary
to Appellants’ argument, “[i]f the claim extends to what is obvious, it is
invalid under § 103” and “the analysis need not seek out precise teachings
directed to the specific subject matter of the challenged claim, for a court
can take account of the inferences and creative steps that a person of
ordinary skill in the art would employ.” Id. at 418—19.
The Examiner finds—and Appellants do not dispute—that except for
the claimed “physically unclonable function (PUF),” Sakata teaches all the
claim elements of claim 1. See Final Act. 3^4. The Examiner finds—and
Appellants acknowledge—that Christensen teaches the claimed “physically
unclonable function (PUF).” See Final Act. 4; See App. Br. 12.
While not relied on for our analysis, we note Appellants acknowledge
PUF was well known in the art. See Spec. Tflf 2—\. In fact, Appellants
acknowledge this invention relates to the known field of PUFs. See Spec.
12.
The Examiner has provided articulated reasoning with a rational
underpinning as to why one skilled in the art would have found it obvious to
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modify Sakata’s method to incorporate Christensen’s teaching of PUF. See
Final Act. 5. In particular, the Examiner finds Sakata and Christensen are
analogous art, and determines one skilled in the art would have found it
obvious to modify Sakata’s method to incorporate Christensen’s teaching of
PUF, so that the modified method can be “used in applications with high
security requirements.” Final Act. 5.
Appellants do not persuasively show why such reasoning is
insufficient. In particular, Appellants’ citing Interconnect Planning Corp. v.
Feil, 774 F.2d 1132, 227 USPQ 543 (Fed. Cir. 1985) (App. Br. 12-13;
Reply Br. 2—3)—a case predating KSR—is unhelpful. Consistent with KSR
and Interconnect, and as discussed above, the Examiner explains why one
skilled in the art would have modified Sakata’s method to incorporate
Christensen’s teaching of PUF, and Appellants fail to show why that
reasoning is insufficient.
Further, Appellants’ assertion that “the capacitance approach of
Christensen and the resistance approach of Sakata are technically
inconsistent and not combinable” (App. Br. 12) is unpersuasive of error,
because Appellants do not provide persuasive argument or objective
evidence to show the argued conclusion is warranted. In particular, the
Examiner’s proposed combination incorporates Christensen’s teaching of
PUF, but not the specific implementation described in a specific sentence of
paragraph 6 of Christensen (“A random variation of memory cell
capacitance is used to implement the physically unclonable function”), as
Appellants argue (App. Br. 12). In fact, Christensen generally states PUFs
were well known in the art and “are the hardware analog of a one-way
function, or essentially random functions bound to a physical device in such
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a way that it is computationally and physically infeasible to predict the
output of the function without actually evaluating it using the physical
device.” Christensen H 1, 3. Further, Christensen cautions: “While the
present invention has been described with reference to the details of the
embodiments of the invention shown in the drawing, these details are not
intended to limit the scope of the invention as claimed in the appended
claims.” Christensen 135. In short, Appellants have not shown that the
teachings of Sakata and Christensen are “not combinable” (App. Br. 12) in
the form proposed by the Examiner. And Appellants’ assertion that “[TJhere
is simply no teaching of in either Sakata or Christensen of substituting the
memory cell capacitance PUF for using ‘a resistance of the magnetic tunnel
junctions’ for the PUF” (App. Br. 13) is not directed to the specific
combination proposed by the Examiner.2
The Examiner’s findings and conclusion are reasonable because 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.” KSR, 550 U.S. at 420—21. Appellants do not
present adequate evidence that the resulting arrangements would have been
“uniquely challenging or difficult for one of ordinary skill in the art” or
2 Appellants’ assertion that “there are several possible ways in which Sakata
. . . and Christensen .. . may be combined, but none of those ways
necessitates the combination of the claimed elements” (App. Br. 13) is
conclusory and do not provide evidence to show error. Further, Appellants
have not cited any legal authority for their argued “necessitates” test. To the
contrary, “[t]he proper question to have asked was whether a [person] of
ordinary skill, facing the wide range of needs created by developments in the
field of endeavor, would have seen a benefit to [modifying Sakata with a
PUF].” KSR, 550 U.S. at 424.
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“represented an unobvious step over the prior art.” Leapfrog Enters., Inc. v.
Fisher-Price, Inc., 485 F.3d 1157, 1162 (Fed. Cir. 2007) (citing KSR, 550
U.S. at 418-19).
In the Reply Brief and for the first time, Appellants belatedly argue:
. . . there is no teaching in Sakata of a circuit to measure
memory cell resistance (upon providing a challenge) in order to
generate the PUF. In fact, short of Applicant’s specification, no
reference has been cited that would provide a motivation to
us[e] memory cell resistance to obtain a PUF as claimed.
Reply Br. 3. Appellants have waived such arguments because they are
untimely, and Appellants have not demonstrated any “good cause” for the
belated presentation. See 37 C.F.R. § 41.41(b)(2).
Accordingly, we agree with the Examiner that applying Christensen’s
teaching of a well-known PUF to Sakata’s method would have predictably
used prior art elements according to their established functions—an obvious
improvement. See KSR, 550 U.S. a 417; Final Act. 5.
Because Appellants have not persuaded us the Examiner erred, we
sustain the Examiner’s rejection of independent claim 1, and independent
claims 11, 16, and 22 for similar reasons.
We also sustain the Examiner’s rejection of corresponding dependent
claims 2, 4—8, 10, 12, 13, 15, 17—20, and 24—30, as Appellants do not
advance separate substantive arguments about them.
Regarding dependent claims 3, 14, 21, and 23, we agree with
Appellants that the Examiner has not adequately mapped the claimed
“wherein the MRAM cells are uninitialized when the response is obtained.”
See App. Br. 13—15; Reply Br. 3^4. The Examiner cites Sakata’s paragraphs
4 and 64 (Final Act. 5; Ans. 4—5), but the cited paragraphs do not teach or
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suggest the disputed claim limitation. Therefore, we are constrained by the
record to reverse the Examiner’s rejection of claims 3, 14, 21, and 23.
Regarding dependent claim 9, we agree with Appellants that the
Examiner has not adequately mapped the claimed “altering at least one of
the generated resistance difference values ... in order to increase a level of
complexity’'' (emphasis added). See App. Br. 15—16; Reply Br. 4—5. The
Examiner cites Sakata’s paragraphs 5 and 6 (Final Act. 7; Ans. 5), but the
cited paragraphs do not teach or suggest the italicized claim limitation.
Therefore, we are constrained by the record to reverse the Examiner’s
rejection of claim 9.
DECISION
We affirm the Examiner’s decision rejecting claims 1, 2, 4—8, 10—13,
15-20, 22, and 2A-30.
We reverse the Examiner’s decision rejecting claims 3, 9, 14, 21, and
23.
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)(iv).
AFFIRMED-IN-PART
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