Case: 22-1037    Document: 40    Page: 1   Filed: 03/13/2023




   United States Court of Appeals
       for the Federal Circuit
                 ______________________

                INTEL CORPORATION,
                      Appellant

                            v.

                PACT XPP SCHWEIZ AG,
                        Appellee
                 ______________________

                       2022-1037
                 ______________________

     Appeal from the United States Patent and Trademark
 Office, Patent Trial and Appeal Board in No. IPR2020-
 00518.
                  ______________________

                 Decided: March 13, 2023
                 ______________________

     ROBERT ALAN APPLEBY, Kirkland & Ellis LLP, New
 York, NY, argued for appellant. Also represented by DIVA
 R. HOLLIS, NATHAN S. MAMMEN, JOHN C. O'QUINN, Wash-
 ington, DC.

     SANFORD IAN WEISBURST, Quinn Emanuel Urquhart &
 Sullivan, LLP, New York, NY, argued for appellee. Also
 represented by NIMA HEFAZI, FREDERICK A. LORIG, Los An-
 geles, CA; MARK YEH-KAI TUNG, Redwood Shores, CA.
                 ______________________

   Before NEWMAN, PROST, and HUGHES, Circuit Judges.
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 2                 INTEL CORPORATION   v. PACT XPP SCHWEIZ AG



 PROST, Circuit Judge.
     The Patent Trial and Appeal Board (“Board”) deter-
 mined that Intel Corp. (“Intel”) failed to show that claim 5
 of 

 (“the ’908 patent”) was un-
 patentable as obvious in light of prior art references Ka-
 bemoto and Bauman. 1 Intel Corp. v. PACT XPP Schweiz
 AG, No. IPR2020-00518, Paper 34, 

 (P.T.A.B. Aug. 9, 2021) (“Final Written Decision”). We re-
 verse and remand.
                         BACKGROUND
                              I
     PACT XPP Schweiz AG (“PACT”) owns the ’908 patent,
 which relates to multiprocessor systems and how proces-
 sors in those systems access data. Multiprocessor systems
 typically store data in several places: there’s a main
 memory, where all of a system’s data is stored, as well as
 various cache memories, where smaller pieces of that same
 data are stored. Cache memories are closer to the proces-
 sors, allowing the processors quicker access to the data
 available in a given cache. And a system can use multiple
 cache levels, where a primary cache is closer to the proces-
 ser but can store less data than a further-away secondary
 cache.
      The use of multiple cache memories can pose problems
 for cache coherency, though. Different caches can have lo-
 cal copies of the same data, so inconsistencies may arise if
 one processor changes its local copy of the data and that
 change isn’t propagated to the other copies of that data.
 That’s why multiprocessor systems often require a mecha-
 nism to monitor and maintain cache coherency. One way
 to maintain cache coherency is by “snooping” along a



     1  

 (“Kabemoto”); U.S. Pa-
 tent No. 5,680,571 (“Bauman”).
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 INTEL CORPORATION    v. PACT XPP SCHWEIZ AG                 3



 shared “bus.” See J.A. 1911; Kabemoto Fig. 3. Another way
 to maintain cache coherency is by using a global, seg-
 mented secondary cache. See Bauman Fig. 6. Both of these
 mechanisms use a shared entity between processors to de-
 tect changes between, and ultimately make changes to, lo-
 cal data copies. See Kabemoto col. 17 l. 27–col. 18 l. 6;
 Bauman col. 5 l. 55–col. 6 l. 40.
                                II
      The ’908 patent claims a multiprocessor system. Intel
 petitioned for inter partes review of claims 4 and 5 of the
 ’908 patent. Claim 5 depends from independent claim 4.
 Before the Board’s Final Written Decision, PACT statuto-
 rily disclaimed claim 4. See Final Written Decision, 

, at *1 n.2, *4. But, to show that claim 5 was
 unpatentable, Intel still had to demonstrate that the prior
 art taught all limitations in claim 4 (in addition to the lim-
 itations added by claim 5) because claim 5 “includes all of
 the limitations of that underlying independent claim.” 

; see, e.g., Vectra Fitness, Inc. v. TNWK Corp., 

 (Fed. Cir. 1998).
    The claim language at issue in this appeal appears in
 underlying independent claim 4 and provides:
     4. A system, the system comprising:
     a processing system comprising
           a plurality of processors; and
           at least one separated cache not part [of] any
           processor;
     ...
     wherein the at least one separated cache comprises
     a separated cache segment for at least some of the
     plurality of processors; the system further compris-
     ing:
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 4                  INTEL CORPORATION    v. PACT XPP SCHWEIZ AG



         an interconnect system interconnecting each of
         the separated cache segments with each of the
         processors, each of the processors with neigh-
         boring processors, and each of the separated
         cache segments with neighboring separated
         cache segments; and
         an arbiter, the arbiter controlling access of a
         processor to the interconnect system.
 ’908 patent claim 4 (emphasis added).
      The claimed interconnect system requires three spe-
 cific interconnections: (1) “each . . . separated cache seg-
 ment[] with each . . . processor[]”; (2) “each . . . processor[]
 with neighboring processors”; and (3) “each . . . separated
 cache segment[] with neighboring separated cache seg-
 ments.” 

 The third of these limitations is relevant to
 this appeal, and we refer to it as the segment-to-segment
 limitation.
                               III
     Intel asserted that the prior art taught a multiproces-
 sor system that used the separated cache and interconnect
 system as described in claim 4. Three annotated figures
 help illustrate Intel’s proposed combination: Kabemoto’s
 Figures 3 and 4 and Bauman’s Figure 6. The annotated
 versions of Kabemoto’s Figures 3 and 4 are shown below,
 cropped to focus on the portions relevant to this appeal.
 Across all three of these annotated figures, processors are
 shown in yellow, secondary caches in blue, and intercon-
 nection systems in gold. See Final Written Decision,
 

, at *7–8; J.A. 932 ¶ 129.
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 INTEL CORPORATION   v. PACT XPP SCHWEIZ AG                  5




 See Final Written Decision, 

, at *7 (Ka-
 bemoto Fig. 3) (annotations in original).




 See J.A. 932 (Kabemoto Fig. 4) (annotations in original).
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 6                 INTEL CORPORATION   v. PACT XPP SCHWEIZ AG



     The annotated version of Bauman’s Figure 6 is shown
 below, also cropped to focus on the portion relevant to this
 appeal.




 See Final Written Decision, 

, at *8 (Bau-
 man Fig. 6) (annotations in original).
     As is relevant to this appeal, we focus on the yellow
 processors in Kabemoto, the blue global, segmented sec-
 ondary cache in Bauman, and the gold interconnection sys-
 tem in both Kabemoto and Bauman.
     Intel contended that a person of ordinary skill in the
 art would combine Kabemoto and Bauman to teach all lim-
 itations in claim 4 by “replac[ing] Kabemoto’s secondary
 caches” with “Bauman’s segmented global [secondary
 cache],” which is a separated cache. Final Written Deci-
 sion, 

, at *8 (cleaned up). A person of
 ordinary skill, Intel argued, would connect Bauman’s
 global, segmented secondary cache “to [Kabemoto’s] snoop
 bus 22 on the outside of [processor] element 14-1” to reach
 a system with the claimed separated cache and intercon-
 nect system. 

 (cleaned up).
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 INTEL CORPORATION   v. PACT XPP SCHWEIZ AG                 7



     PACT did not dispute that the combination of Ka-
 bemoto and Bauman taught each limitation of claim 4;
 PACT only argued that Intel failed to demonstrate a moti-
 vation to combine Kabemoto and Bauman. See J.A. 601.
 Nevertheless, the Board purported to “agree” with PACT
 that Intel failed to demonstrate that the prior art disclosed
 the segment-to-segment limitation. Final Written Deci-
 sion, 

, at *7–8; see Oral Arg. at 17:20–29,
 No. 22-1037, https://oralarguments.cafc.uscourts.gov/de-
 fault.aspx?fl=22-1037_12072022.mp3 (PACT counsel ad-
 mitting “in all candor” that PACT “did not make this . . .
 argument” before the Board). The Board also concluded
 that Intel failed to show that a person of ordinary skill in
 the art would have been motivated to combine the teach-
 ings of Kabemoto and Bauman. Final Written Decision,
 

, at *8–11. And because the Board deter-
 mined that Intel failed to prove the obviousness of each lim-
 itation in claim 4, it upheld the patentability of claim 5.
 See 

.
     Intel appeals, and we have jurisdiction under 

(a)(4)(A).
                         DISCUSSION
     What the prior art discloses and whether a person of
 ordinary skill would have been motivated to combine prior
 art references are both fact questions that we review for
 substantial evidence. PAR Pharm., Inc. v. TWI Pharms.,
 Inc., 

 (Fed. Cir. 2014). “Substantial ev-
 idence is such relevant evidence as a reasonable mind
 might accept as adequate to support a conclusion.” Novar-
 tis AG v. Torrent Pharms. Ltd., 

 (Fed. Cir. 2017) (cleaned up).
     Intel argues that two of the Board’s conclusions about
 underlying independent claim 4 lack substantial evidence.
 First, Intel asserts that substantial evidence does not sup-
 port the Board’s determination that the prior art fails to
 disclose the segment-to-segment limitation. And second,
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 8                 INTEL CORPORATION   v. PACT XPP SCHWEIZ AG



 Intel contends that substantial evidence does not support
 the Board’s determination that there was no motivation to
 combine Kabemoto and Bauman. We agree on both counts.
                               I
     Intel first asserts that Bauman’s Figure 6 teaches the
 segment-to-segment limitation. Appellant’s Br. 46–48. We
 agree and conclude that the Board’s determination that the
 segment-to-segment limitation wasn’t in the prior art lacks
 substantial evidence.
      Intel used a color-coded version of Bauman’s Figure 6
 to illustrate this teaching, the relevant portion of which is
 reproduced below:




 See Final Written Decision, 

, at *8 (anno-
 tations in original).
     As Bauman explains, its Figure 6 “illustrates the data
 path between . . . processors, the second-level cache, and
 the memory.” Bauman col. 11 ll. 18–20. The second-level
 cache consists of “Segments 0–3,” 

 at col. 11 ll. 20–23,
 each of which is labeled “SEG” and identified in blue in the
 color-coded figure above, Final Written Decision, 

, at *8. The data path—i.e., the interconnection
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 INTEL CORPORATION   v. PACT XPP SCHWEIZ AG                 9



 system linking the processors and second-level cache—is
 shown in gold. 

     The Board, in finding that Intel failed to show the seg-
 ment-to-segment limitation in the asserted prior art,
 faulted Intel for failing to explain how Kabemoto’s “snoop
 bus 22” connected each cache segment to its neighboring
 segment. See 

 at *7–8. According to the Board, this was
 a fatal flaw because, per the Board’s understanding, Intel
 relied on Kabemoto’s snoop bus 22 to disclose all three lim-
 itations of the claimed “interconnect system” in the ’908 pa-
 tent. See 

 But Intel relied on Bauman to teach a
 separated and segmented cache in its petition and through-
 out the proceedings. E.g., J.A. 216–17 (citing J.A. 933–35
 ¶¶ 133–34).

     Bauman’s Figure 6 teaches—if not plainly illustrates—
 the segment-to-segment limitation of the claimed intercon-
 nect system: each blue cache segment is connected to its
 neighboring blue cache segments via the gold data path.
 That was Intel and PACT’s understanding at the Board,
 and that’s our understanding from the record on appeal.
 We can discern no other reasonable understanding of this
 figure. 2 Accordingly, the Board’s determination that the


     2   It could be that the Board reached the opposite con-
 clusion based on claim construction of “interconnect sys-
 tem,” but neither Intel nor PACT raised such an
 explanation in their briefing. Although the Board con-
 tended that it “need not reach the [claim-construction] is-
 sue of whether” the three “interconnect system” limitations
 were limited to “direct” connections, the only way the
 Board’s segment-to-segment conclusion makes sense is if
 the Board did, in fact, construe “interconnect system” to re-
 quire direct connections and exclude indirect connections.
 See Final Written Decision, 

, at *3.
     The Board’s reasoning as to why Intel failed to show
 the segment-to-segment limitation appears to reject Intel’s
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 10                INTEL CORPORATION    v. PACT XPP SCHWEIZ AG



 prior art did not teach the segment-to-segment limitation
 lacks substantial evidence, and we reverse it.

                               II
     Intel also argues that the Board’s rejection of its
 “known-technique” rationale for a motivation to combine
 lacks substantial evidence. 3 Appellant’s Br. 57–63 (citing
 KSR Int’l Co. v. Teleflex Inc., 

 (2007)); see also
 Intel Corp. v. Qualcomm Inc., 

 (Fed. Cir.
 2021) (determining that the Board’s reasons for finding a
 lack of motivation to combine were not supported by sub-
 stantial evidence “[u]nder applicable legal principles”). We
 agree and reverse the Board’s contrary finding.
                               A
     The motivation-to-combine analysis is a flexible one.
 “[A]ny need or problem known in the field of endeavor at
 the time of invention and addressed by the patent can pro-
 vide a reason for combining the elements in the manner


 proffered construction that the “interconnect system” limi-
 tations can be shown via direct or indirect connections.
 Even if the Board is right that Intel’s proposed combination
 relied on Kabemoto’s “snoop bus 22” to teach the segment-
 to-segment limitation, Kabemoto’s snoop bus 22 does so—
 just with indirect connections. Should there be only one
 connection from the whole of Bauman’s global secondary
 cache to Kabemoto’s snoop bus 22, see 

 at *7–8, each of
 the segments in that secondary cache would still be con-
 nected to each other through their shared singular connec-
 tion to the snoop bus.
     3    Intel offered three motivations to combine Ka-
 bemoto and Bauman, one of which was premised on a
 known-technique rationale and all of which the Board re-
 jected. See Final Written Decision, 

,
 at *8–11. We discuss only the known-technique rationale
 because it is sufficient for reversal.
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 INTEL CORPORATION   v. PACT XPP SCHWEIZ AG                 11



 claimed.” KSR, 

 (emphasis added). And “[a]
 person of ordinary skill is also a person of ordinary creativ-
 ity, not an automaton.” 

. So, “in many cases[,] a
 person of ordinary skill will be able to fit the teachings of
 multiple patents together like pieces of a puzzle.” 

. That’s why the motivation-to-combine 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.” 

.
     Additionally, “universal” motivations known in a par-
 ticular field to improve technology provide “a motivation to
 combine prior art references even absent any hint of sug-
 gestion in the references themselves.” Intel, 21 F.4th
 at 797–99 (cleaned up) (emphasis in original) (determining
 that the Board’s rejection of “increasing energy efficiency,”
 a “generic concern” in electronics, as a motivation to com-
 bine lacked substantial evidence (cleaned up)).
     Similarly, “if a technique has been used to improve one
 device, and a person of ordinary skill in the art would rec-
 ognize that it would improve similar devices in the same
 way, using the technique is obvious unless its actual appli-
 cation is beyond his or her skill.” KSR, 

.
 This is the so-called “known-technique” rationale. And if
 there’s a known technique to address a known problem us-
 ing “prior art elements according to their established func-
 tions,” then there is a motivation to combine. Intel,
 21 F.4th at 799–800. And we specify address a known
 problem because “[i]t’s not necessary to show that a combi-
 nation is the best option, only that it be a suitable option.”
 Id. at 800 (cleaned up) (emphasis in original).
     Assessing whether claimed subject matter involves the
 “application of a known technique” will “[o]ften” require “a
 court to look to interrelated teachings of multiple patents;
 the effects of demands known to the design community or
 present in the marketplace; and the background knowledge
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 12                INTEL CORPORATION   v. PACT XPP SCHWEIZ AG



 possessed by a person having ordinary skill in the art.”
 KSR, 550 U.S. at 417–18.
                              B
     Before the Board, Intel asserted that a person of ordi-
 nary skill would have been motivated to combine Kabemoto
 and Bauman because they “relate to the same field of mul-
 tiprocessor . . . systems” and “address the same problem:
 maintaining cache coherency.” Intel Corp. v. PACT XPP
 Schweiz AG, No. IPR2020-00518, Paper 1, at 48 (P.T.A.B.
 Feb. 7, 2020) (“Petition”); see Final Written Decision,
 

, at *11 (citing Petition, at 48). So, Intel
 reasoned, a person of ordinary skill “would have naturally
 turned to Bauman’s segmented [global secondary] cache to
 use . . . in Kabemoto” since Bauman’s separated cache was
 known to address the same cache-coherency issue that Ka-
 bemoto also sought to address, just through a different
 mechanism—a shared snoop bus. Petition, at 48–49.
     The Board rejected Intel’s known-technique rationale.
 The Board stated that “[i]f . . . Kabemoto already addresses
 [the] problem [of cache coherency] through the use of a
 known technique similar to that of Bauman’s, [it] fail[ed]
 to see why one of ordinary skill in the art would regard
 Bauman’s technique as an obvious improvement to Ka-
 bemoto.” Final Written Decision, 

, at *11.
 But the Board’s reasoning belies its conclusion. That Ka-
 bemoto and Bauman address the same problem and that
 Bauman’s cache was a known way to address that problem
 is precisely the reason that there’s a motivation to combine
 under KSR and our precedent.
     There is a motivation to combine when a known tech-
 nique “has been used to improve one device, and a person
 of ordinary skill in the art would recognize that it would
 improve similar devices in the same way,” KSR, 

, using the “prior art elements according to their es-
 tablished functions,” Intel, 21 F.4th at 799–800. And here,
 there’s no dispute that using a global, segmented
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 INTEL CORPORATION   v. PACT XPP SCHWEIZ AG                13



 secondary cache “has been used to improve” cache coher-
 ency in multiprocessor systems—as in Bauman—and a
 person of ordinary skill would “recognize that” such a cache
 “would improve similar” multiprocessor systems—like the
 one in Kabemoto—by addressing that same cache coher-
 ency problem. See KSR, 

. Bauman itself
 explains that its global, segmented secondary cache is one
 of two “primary mechanisms” by which its claimed system
 “accomplishe[s]” cache coherency. Bauman col. 5 ll. 55–59.
 There’s accordingly also no dispute that such a combina-
 tion would constitute a use of Bauman’s secondary cache
 “according to [its] established function[].” Intel, 21 F.4th
 at 799–800.
     And contrary to the Board’s suggestion, Intel never had
 to show that replacing Kabemoto’s secondary cache with
 Bauman’s secondary cache was an “improvement” in a cat-
 egorical sense. See Final Written Decision, 

, at *11. Intel just had to show that Bauman’s sec-
 ondary cache was a “suitable option” to replace Kabemoto’s
 secondary cache. Intel, 

 (emphasis omitted).
     It’s enough for Intel to show that there was a known
 problem of cache coherency in the art, that Bauman’s sec-
 ondary cache helped address that issue, and that combin-
 ing the teachings of Kabemoto and Bauman wasn’t beyond
 the skill of an ordinary artisan. Nothing more is required
 to show a motivation to combine under KSR, so we reverse
 the Board’s finding to the contrary.
                              III
    Although we reverse the two factual findings discussed
 above, we must remand for the Board to address any re-
 maining dispute about the patentability of claim 5.
     Claim 5 recites: “The bus system of claim 4 where the
 arbiter is operable to allow processor access in chronologi-
 cal sequence.” ’908 patent claim 5. Intel relied on prior art
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 14                INTEL CORPORATION   v. PACT XPP SCHWEIZ AG



 Chaney to teach this limitation. 4 See J.A. 221–26, 259–64.
 PACT did not dispute that Chaney taught this added
 “chronological sequence” limitation. See Intel Corp. v.
 PACT XPP Schweiz AG, No. IPR2020-00518, Paper 21,
 at 32–33, 42–43 (P.T.A.B. Nov. 16, 2020) (PACT Response);
 Intel Corp. v. PACT XPP Schweiz AG, No. IPR2020-00518,
 Paper 26, at 18, 28 (P.T.A.B. Feb. 9, 2021) (Intel Reply).
 But because the Board failed to analyze the invention of
 claim 5 as a whole, we must remand.
                        CONCLUSION
     We have considered PACT’s remaining arguments and
 find them unpersuasive. For the foregoing reasons, we re-
 verse the Board’s findings related to the above-discussed
 limitations (which appear in claim 5 by virtue of its depend-
 ence from claim 4) and remand for further proceedings con-
 sistent with this opinion.
                REVERSED AND REMANDED
                              COSTS
 No costs.




      4   

 (“Chaney”).