Rovalma, S.A. v. Bohler-Edelstahl Gmbh & Co. Kg ( 2017 )


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  •   United States Court of Appeals
    for the Federal Circuit
    ______________________
    ROVALMA, S.A.,
    Appellant
    v.
    BOHLER-EDELSTAHL GMBH & CO. KG,
    Appellee
    ______________________
    2016-2233
    ______________________
    Appeal from the United States Patent and Trademark
    Office, Patent Trial and Appeal Board in No. IPR2015-
    00150.
    ______________________
    Decided: May 11, 2017
    ______________________
    MARC WADE VANDER TUIG, Senniger Powers LLP, St.
    Louis, MO, argued for appellant. Also represented by
    ROBERT M. EVANS, JR., JOHN R. SCHROEDER.
    MAXWELL JAMES PETERSEN, Lewis Brisbois Bisgaard
    & Smith, LLP, Chicago, IL, argued for appellee. Also
    represented by THOMAS A. DOUGHERTY, Denver, CO.
    ______________________
    Before WALLACH, TARANTO, and STOLL, Circuit Judges.
    TARANTO, Circuit Judge.
    2         ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG
    Rovalma, S.A. owns U.S. Patent No. 8,557,056, which
    describes and claims methods for making steels with
    certain desired thermal conductivities. In October 2014,
    Böhler-Edelstahl GmbH & Co. KG (Böhler) petitioned the
    Patent Trial and Appeal Board for an inter partes review
    of claims 1–4 of the ’056 patent. The Board instituted a
    review based on Böhler’s construction of the claims at
    issue. In its final written decision, however, the Board
    rejected Böhler’s construction and adopted Rovalma’s
    construction instead. Böhler had not submitted argu-
    ments or evidence for unpatentability based on Rovalma’s
    construction. Nevertheless, the Board determined that
    Rovalma’s own submissions demonstrated that the
    claims, construed as Rovalma urged, would have been
    obvious to a relevant skilled artisan over the same prior
    art that Böhler invoked.
    Rovalma appeals. It argues both that substantial evi-
    dence does not support the Board’s determination and
    that the Board committed prejudicial procedural errors in
    relying on Rovalma’s own submissions when determining
    that the claims would have been obvious under Rovalma’s
    construction. We conclude that the Board did not set
    forth its reasoning in sufficient detail for us to determine
    what inferences it drew from Rovalma’s submissions. We
    therefore cannot determine whether the Board’s decision
    was substantively supported and procedurally proper. We
    vacate the Board’s decision and remand for further pro-
    ceedings.
    I
    The ’056 patent addresses hot-work steels. It is un-
    disputed that hot-work steels are used at high tempera-
    tures and that the ability to conduct and thereby remove
    heat—thermal conductivity—is important for such steels.
    According to the patent, hot-work steels disclosed in the
    prior art had thermal conductivities of approximately 16–
    37 W/mK (Watts per meter-Kelvin), which were inade-
    ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG             3
    quate for certain applications. ’056 patent, col. 1, lines
    50–52; col. 4, lines 11–14. The patent claims processes for
    “setting” the thermal conductivity of a hot-work steel at
    room temperature to more than 42 W/mK (higher in the
    dependent claims). 
    Id., col. 21,
    line 59 through col. 22,
    line 64. The ’056 patent discloses an allegedly inventive
    process that, to achieve such higher thermal conductivi-
    ties, focuses on carbides (metal-carbon compounds) in the
    steel’s matrix, or lattice, structure. 
    Id., col. 4,
    lines 35–63.
    The summary of the invention states that “an internal
    structure of the steel is metallurgically created in a de-
    fined manner such that the carbidic constituents thereof
    have a defined electron and phonon density and/or the
    crystal structure thereof has a mean free length of the
    path for the phonon and electron flow that is determined
    by specifically created lattice defects.” 
    Id., col. 4,
    lines 37–
    43. Alternatively, the internal structure may have “in its
    carbidic constituents an increased electron and phonon
    density and/or which has as a result of a low defect con-
    tent in the crystal structure of the carbides and of the
    metallic matrix surrounding them an increased mean free
    length of the path for the phonon and electron flow.” 
    Id., col. 4,
    lines 54–58.
    The patent includes four claims. Claim 1 recites:
    1. A process for setting a thermal conductivity of a
    hot-work steel, which comprises the steps of:
    providing a hot-work steel, including carbidic
    constituents and, by weight, 2–10% Mo+W+V
    [molybdenum + tungsten + vanadium];
    metallurgically creating an internal structure
    of the steel in a defined manner such that car-
    bidic constituents thereof have at least one of
    a defined electron and phonon density and a
    crystal structure thereof having a mean free
    length of a path for a phonon and electron flow
    4          ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG
    being determined by specifically created lat-
    tice defects;
    selecting:
    a) a surface fraction and thermal conduc-
    tivity of the carbidic constituents and a
    particular surface fraction and thermal
    conductivity of a matrix material contain-
    ing the carbidic constituents; or
    b) a volume fraction and thermal conduc-
    tivity of the carbidic constituents and
    thermal conductivity of the matrix mate-
    rial containing the carbidic constituents;
    and
    setting the thermal conductivity of the steel at
    room temperature to more than 42 W/mK.
    
    Id., col. 21,
    line 59 through col. 22, line 14.
    Claims 2 and 3, which depend on claim 1, require set-
    ting the thermal conductivities of the steel to more than
    48 and 55 W/mK respectively. ’056 patent, col. 22, lines
    15–20. Claim 4, an independent claim, is similar to claim
    1, but contains some different language in the “creating”
    step, including a reference to a “metallic matrix” sur-
    rounding the carbides. 
    Id., col. 22,
    lines 21–64.
    In October 2014, Böhler petitioned for inter partes re-
    view of all four claims of the ’056 patent under 35 U.S.C.
    §§ 311–312. In its Petition, Böhler argued that the claims
    should be construed to cover the specific chemical compo-
    sitions described in the specification, whether or not
    created according to the process steps—“providing,”
    “creating,” “selecting,” and “setting”—recited in the
    claims. See Petition for Inter Partes Review 4–20, Böhler-
    Edelstahl GmbH & Co. KG v. Rovalma, S.A., No.
    IPR2015-00150 (P.T.A.B. Oct. 24, 2014), Paper No. 1
    (Petition). Böhler argued that the claims, so construed,
    ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG        5
    would have been obvious over various prior-art references
    that disclosed those compositions, including European
    Patent No. EP 0,787,813 (EP ’813). Petition 20–59.
    Böhler did not address whether the asserted prior-art
    references disclosed the “providing,” “creating,” “select-
    ing,” and “setting” steps of the ’056 patent’s claims. See
    
    id. Nor did
    Böhler address whether those steps would
    have been obvious to one of ordinary skill in the art. See
    
    id. In April
    2015, the Board, acting as the delegate of the
    Patent and Trademark Office’s Director, 37 C.F.R.
    § 42.4(a), instituted a review of the challenged claims
    under 35 U.S.C. § 314. See Institution Decision, Böhler-
    Edelstahl GmbH & Co. KG v. Rovalma, S.A., No.
    IPR2015-00150, 
    2015 WL 1871000
    (P.T.A.B. Apr. 22,
    2015). In its decision to institute, the Board adopted
    Böhler’s proposed claim construction. 
    Id. at *3–8.
    Apply-
    ing that construction, the Board concluded that Böhler
    had established a reasonable likelihood of prevailing on
    its assertion that the challenged claims would have been
    obvious over the asserted prior-art references. 
    Id. at *8–
    9.
    After the review was instituted, Rovalma, in its Pa-
    tent Owner’s Response, argued against the claim con-
    struction that the Board had relied on in instituting the
    review. Patent Owner Response 19–51, Böhler-Edelstahl,
    No. IPR2015-00150 (P.T.A.B. Aug. 14, 2015), Paper No.
    25. Rovalma argued that the claims should be construed
    to require performance of the processes recited in the
    claims, not simply to cover the compositions described in
    the specification. As background for its proposed claim
    construction—according to Rovalma’s statement at oral
    argument in this court, to counteract an enablement-
    based objection to its proposed construction—Rovalma
    submitted additional evidence and argument regarding
    thermoprocessing.
    6         ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG
    Rovalma argued that a person of ordinary skill in the
    art at the time of the invention, given the specification,
    would have been able to predict the formation of certain
    carbides based on particular heat treatments. 
    Id. at 4.
    Rovalma also argued that a person of ordinary skill would
    have been able to use software tools, such as Thermo-
    Calc, to carry out the needed calculations. 
    Id. at 4–5.
    In
    addition, Rovalma argued, based on H. Bayati & R. El-
    liott, Influence of Matrix Structure on Physical Properties
    of an Alloyed Ductile Cast Iron, 15 Materials Sci. & Tech.
    265 (1999), that the thermal conductivity of a steel de-
    pends on lattice defects and impurities. Patent Owner
    Response 7. The passage of Bayati and Elliott cited by
    Rovalma states that matrix structure and thermal pro-
    cessing also affect thermal conductivity. See, e.g., Bayati
    & 
    Elliot, supra, at 265
    (“Matrix structure is shown to play
    a significant role in determining the thermal conductivity
    of the ductile iron.”); 
    id. (“Heat transport
    also depends on
    lattice defects, microstructure, impurities, and the pro-
    cessing of the metal or alloy.”).
    In its Petitioner’s Reply, Böhler repeated its conten-
    tion that the claims should be construed to cover chemical
    compositions, not processes. Petitioner’s Reply 5–21,
    Böhler-Edelstahl, No. IPR2015-00150 (P.T.A.B. Nov. 11,
    2015), Paper No. 30. It did not argue, in the alternative,
    that the claims would have been obvious under Rovalma’s
    proposed claim construction. Nor did it address Roval-
    ma’s thermoprocessing submissions, except to argue that
    Rovalma’s extrinsic evidence was irrelevant to the proper
    construction of the claims. See 
    id. at 7–8.
        At the oral argument, the Board extensively ques-
    tioned Rovalma’s counsel about the effect of its thermo-
    processing submissions on the patentability of the claims
    under the claim construction urged by Rovalma. See
    Record of Oral Hearing 53–87, 94–95, Böhler-Edelstahl,
    No. IPR2015–00150 (P.T.A.B. Mar. 30, 2016), Paper No.
    41. In particular, the Board asked Rovalma to discuss the
    ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG            7
    notion that it would have been obvious to create steel with
    the claimed thermal conductivities in light of the prior-art
    references advanced by Böhler because: (a) those refer-
    ences disclosed the chemical compositions described in the
    ’056 patent specification; and (b) Rovalma’s submissions
    showed that a person of ordinary skill in the art would
    have known how to optimize those compositions to
    achieve the desired properties, including thermal conduc-
    tivity. See, e.g., 
    id. at 67
    (“But see, in [Bayati and Elliott]
    I believe the abstract is telling us the matrix structure is
    shown to play a significant role in determining thermal
    conductivity of ductile iron. Why wouldn’t one of ordinary
    skill in the art, given the Böhler reference and [Bayati
    and Elliott], understand that the matrix structure[] is
    important for thermal conductivity and you would want to
    optimize it for a given composition?”).
    In April 2016, the Board found the challenged claims
    unpatentable. The Board rejected Böhler’s claim con-
    struction, and adopted Rovalma’s. Final Written Decision
    8–17, Böhler-Edelstahl, No. IPR2015-00150 (P.T.A.B. Apr.
    20, 2016). Applying Rovalma’s construction, the Board
    then determined that the claims would have been obvious
    over “the asserted prior art as read in light of the
    knowledge of the ordinarily skilled artisan.” Final Writ-
    ten Decision 22; see 
    id. at 20–22.
    The Board relied on
    Rovalma’s own submissions for key findings about what a
    relevant skilled artisan would have taken from the Böh-
    ler-asserted prior art.
    Specifically, the Board rejected Rovalma’s argument
    that the asserted prior-art references did not disclose
    setting the thermal conductivity of a steel by selecting a
    surface or volume fraction of carbides or by manipulating
    the steel’s microstructure in a defined manner. See 
    id. Instead, the
    Board found that a person of ordinary skill
    “would have recognized that thermal processing condi-
    tions affect internal structure and, thus, thermal proper-
    ties of steel.” 
    Id. at 21.
    The Board also found that a
    8         ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG
    person of ordinary skill would have been motivated to
    increase the thermal conductivity of steel and would have
    had a reasonable expectation of success in doing so. 
    Id. at 22.
    The Board further found that a person of ordinary
    skill would have “inherently completed the ‘selecting’
    steps set forth in the challenged claims.” 
    Id. To support
    each of those findings, the Board relied on Rovalma’s
    thermal-processing submissions and Rovalma’s state-
    ments at the oral argument. See 
    id. at 20–22.
        Rovalma appeals the Board’s decision. We have juris-
    diction under 28 U.S.C. § 1295(a)(4)(A).
    II
    We review the Board’s decisions under the Adminis-
    trative Procedure Act (APA). Taking “due account . . . of
    the rule of prejudicial error,” we must “hold unlawful and
    set aside agency action, findings, and conclusions found to
    be . . . arbitrary, capricious, an abuse of discretion, or
    otherwise not in accordance with law,” “without ob-
    servance of procedure required by law,” or “unsupported
    by substantial evidence.” 5 U.S.C. § 706. In applying
    those standards, “we will uphold a decision of less than
    ideal clarity if the agency’s path may reasonably be dis-
    cerned,” but “we may not supply a reasoned basis for the
    agency’s action that the agency itself has not given.”
    Bowman Transp., Inc. v. Ark.-Best Freight Sys., Inc., 
    419 U.S. 281
    , 285–86 (1974); SEC v. Chenery Corp., 
    332 U.S. 194
    , 196–97 (1947). Thus, the Board must, as to issues
    made material by the governing law, set forth a sufficient-
    ly detailed explanation of its determinations both to
    enable meaningful judicial review and to prevent judicial
    intrusion on agency authority. See SEC v. Chenery Corp.
    
    318 U.S. 80
    , 88, 94 (1943); Personal Web Technologies,
    LLC v. Apple, Inc., 
    848 F.3d 987
    , 991–93 (Fed. Cir. 2017);
    In re NuVasive, Inc., 
    842 F.3d 1376
    , 1382–83 (Fed. Cir.
    2016).
    ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG         9
    In challenging the Board’s decision in this case,
    Rovalma argues both evidentiary insufficiency and proce-
    dural inadequacy. We address those arguments in turn.
    We conclude that a remand is advisable in both respects,
    for related reasons.
    A
    Rovalma challenges the Board’s implicit factual find-
    ings that a person of ordinary skill (1) would have appre-
    ciated that the claimed thermal conductivities could be
    achieved by practicing the claimed process steps, (2)
    would have been motivated to increase the thermal con-
    ductivities of the steels disclosed in the prior art to
    achieve the claimed thermal conductivities, and (3) would
    have had a reasonable expectation of success in achieving
    the claimed thermal conductivities. We conclude that the
    Board did not sufficiently explain the basis for its obvi-
    ousness determinations to permit us to resolve the sub-
    stantial-evidence issues raised by Rovalma.
    The Supreme Court has recognized the importance of
    clarity with respect to obviousness determinations. For
    example, in KSR International Co. v. Teleflex Inc., 
    550 U.S. 398
    (2007), the Court explained that determining
    whether a person of ordinary skill would have been moti-
    vated to combine known elements to arrive at the patent-
    ed invention often requires a factfinder to compare the
    “interrelated teachings of multiple patents; the effects of
    demands known to the design community or present in
    the marketplace; and the background knowledge pos-
    sessed by a person having ordinary skill in the art.” 
    Id. at 418.
    “To facilitate review,” the Court added, “this analy-
    sis should be made explicit.” 
    Id. We have
    repeatedly
    insisted on such explanations in reviewing the adequacy
    of the Board’s analysis—both as a matter of obviousness
    law and as a matter of administrative law. We have
    noted that the amount of explanation needed varies from
    case to case, depending on the complexity of the matter
    10        ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG
    and the issues raised in the record. See Personal Web
    
    Technologies, 848 F.3d at 991
    –94; Ariosa Diagnostics v.
    Verinata Health, Inc., 
    805 F.3d 1359
    , 1364–67 (Fed. Cir.
    2015); In re Lee, 
    277 F.3d 1338
    , 1342–46 (Fed. Cir. 2002).
    In this case, the Board did not adequately explain the
    basis for the findings that Rovalma challenges. The
    Board found that EP ’813 and the other asserted prior-art
    references expressly disclosed steel compositions “includ-
    ing carbidic constituents and, by weight, 2–10%
    Mo+W+V,” as required by the “providing” steps in claims
    1 and 4 of Rovalma’s patent. Final Written Decision 22.
    But the Board did not sufficiently lay out the basis for its
    implicit findings regarding the remaining process limita-
    tions. With respect to those limitations, the Board found
    that a person of ordinary skill “would have at least inher-
    ently completed the ‘selecting’ steps” and apparently
    determined that the other steps would have been obvious
    in view of Rovalma’s submissions. 
    Id. But it
    did not
    explain the evidentiary basis for those determinations,
    and Böhler did not provide any explanation regarding the
    process claim elements that the Board could adopt as its
    own.
    Nor did the Board adequately explain why a person of
    ordinary skill in the art would have been motivated to
    increase the thermal conductivities of the steels disclosed
    in the prior art. Stating that EP ’813 and other asserted
    prior-art references disclosed “the desirability of steels
    having high thermal conductivity,” the Board found that a
    person of ordinary skill “would have had reason to in-
    crease the thermal conductivity of these compositions.”
    
    Id. But the
    Board did not cite any evidence, either in the
    asserted prior-art references or elsewhere in the record,
    with sufficient specificity for us to determine whether a
    person of ordinary skill in the art would have been so
    motivated. As Rovalma points out, it does not necessarily
    follow from prior-art disclosures of the general desirabil-
    ity of high thermal conductivities that a person of ordi-
    ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG       11
    nary skill would have been motivated to increase thermal
    conductivity beyond levels previously achieved.
    Adequate explanation is also lacking for why a person
    of ordinary skill in the art would have reasonably ex-
    pected success in achieving the claimed thermal conduc-
    tivities. The Board found that Rovalma’s submissions
    disclosed that a person of ordinary skill would have
    understood “heat transfer through metallic matrices and
    entrained metal carbides” and “the ability to model the
    effects of thermal processing on steel alloy microstruc-
    ture,” and from that finding the Board inferred that a
    person of ordinary skill “would have had a reasonable
    expectation of success in arriving at the claimed inven-
    tion.” 
    Id. Again, however,
    the Board did not cite any
    evidence to support the inference that a person of ordi-
    nary skill would have reasonably expected to achieve the
    specific thermal conductivities recited in the claims.
    Without more explanation than we have, we are not
    prepared to reach a bottom-line judgment on Rovalma’s
    substantial-evidence challenge. The Board has not pro-
    vided a sufficiently focused identification of the relevant
    evidence or explanation of its inferences for us to confi-
    dently review its decision and avoid usurping its fact-
    finding authority. See Consolidated Edison Co. of N.Y. v.
    NLRB, 
    305 U.S. 197
    , 229 (1938) (“Substantial evidence
    . . . means such relevant evidence as a reasonable mind
    might accept as adequate to support a conclusion.”).
    Accordingly, as we have concluded in similar circum-
    stances, these deficiencies call for a vacatur and remand
    for further explanation from the Board. See, e.g., Icon
    Health & Fitness, Inc. v. Strava, Inc., 
    849 F.3d 1034
    , 1044
    (Fed. Cir. 2017); In re Van Os, 
    844 F.3d 1359
    , 1360–62
    (Fed. Cir. 2017); Personal Web 
    Technologies, 848 F.3d at 991
    –94; Ariosa 
    Diagnostics, 805 F.3d at 1364
    –67. We
    next address Rovalma’s procedural challenge.
    12        ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG
    B
    Rovalma makes essentially two arguments in favor of
    its contention that the Board committed prejudicial
    procedural error. One argument is that the inter partes
    review statute prohibited the Board, after adopting
    Rovalma’s own claim construction, from relying on
    Rovalma’s own submissions in determining that the
    claims, so construed, would have been obvious over the
    Böhler-asserted prior art. The other argument is that
    Rovalma was denied adequate notice of and an adequate
    opportunity to address the possibility that the Board
    would rely on Rovalma’s submissions, as it ultimately did.
    1
    We reject Rovalma’s argument that the Board “ex-
    ceeded its statutory authority.” Appellant’s Br. 24 (capi-
    talization in heading omitted). To support that argument,
    Rovalma relies entirely on In re Magnum Oil Tools Inter-
    national, Ltd., 
    829 F.3d 1364
    (Fed. Cir. 2016). That
    decision, however, does not preclude the Board from
    relying on a patent owner’s own submissions in determin-
    ing unpatentability in the way the Board did here, as long
    as the patent owner had adequate notice and an adequate
    opportunity to be heard—procedural requirements that
    we address in the next subsection of this opinion.
    The court in Magnum Oil focused principally on the
    question of whether the Board had violated 35 U.S.C.
    § 316(e) by improperly relying on a burden-shifting
    framework that required the patent owner, not the peti-
    tioner, to prove the unpatentability of claims on which
    review was instituted. We held that the Board had en-
    gaged repeatedly in such impermissible burden shifting.
    Magnum 
    Oil, 829 F.3d at 1375
    –79. We then explained
    that the evidence in the record did not permit the findings
    of fact needed to establish unpatentability, noting that on
    the crucial points the petitioner’s evidence consisted of no
    ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG       13
    more than legally insufficient “conclusory statements.”
    
    Id. at 1380.
        In the final paragraph of the opinion, we addressed
    the Director’s broad contention that the Board was free to
    make an argument for the petitioner simply because the
    argument “‘could have been included in a properly-drafted
    petition.’” 
    Id. at 1377,
    1380 (quoting Intervenor’s Br. 34,
    Magnum Oil, 
    829 F.3d 1364
    , ECF No. 41). We rejected
    “the PTO’s position that the Board is free to adopt argu-
    ments on behalf of petitioners that could have been, but
    were not, raised by the petitioner during an IPR” and
    explained that “the Board must base its decision on
    arguments that were advanced by a party, and to which
    the opposing party was given a chance to respond.” 
    Id. at 1381
    (citing SAS Inst., Inc. v. ComplementSoft, LLC, 
    825 F.3d 1341
    , 1351 (Fed. Cir. 2016)).
    Magnum Oil, we conclude, is best understood as sup-
    porting Rovalma’s contention only with respect to the
    requirement of notice and opportunity to be heard, and no
    further. Here, the Board resolved an active dispute over
    claim construction in favor of the patent owner and, using
    the patent owner’s construction, relied on the patent
    owner’s own submissions to determine how a skilled
    artisan would have read the very prior-art references on
    which the petitioner’s obviousness challenge was based. 1
    That was not the situation in Magnum Oil. And our
    1    Rovalma does not dispute that a skilled artisan’s
    background knowledge is relevant to the reading of the
    prior art on which the obviousness challenge is based and
    that it is permissible, and sometimes even necessary, to
    establish such background knowledge by pointing to other
    prior art. See, e.g., Van 
    Os, 844 F.3d at 1361
    ; K/S Himpp
    v. Hear-Wear Techs., LLC, 
    751 F.3d 1362
    , 1365–66 (Fed.
    Cir. 2014); Randall Mfg. v. Rea, 
    733 F.3d 1355
    , 1362–63
    (Fed. Cir. 2013).
    14        ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG
    statement that the Board must rely on “arguments that
    were advanced by a 
    party,” 829 F.3d at 1381
    , does not, by
    its terms, preclude the Board from relying on arguments
    made by a party and doing its job, as adjudicator, of
    drawing its own inferences and conclusions from those
    arguments, even when the result is use of the party’s
    submissions against it—subject, of course, to the provision
    of adequate notice and opportunity to be heard.
    We do not see any reason that Magnum Oil should be
    read more broadly to establish a statutory rule prohibit-
    ing the Board from ever relying on a patent owner’s own
    submissions in determining unpatentability, even as
    evidence of the knowledge a relevant skilled artisan
    would bring to reading the prior art asserted by the
    petitioner. Magnum Oil was addressing only the Direc-
    tor’s broad assertion that the Board could raise any
    argument that could have been included in a petition.
    Rejecting that broad assertion does not imply precluding
    reliance on a patent owner’s own submissions (part of the
    record created by the parties) essentially as admissions, if
    adequate notice and opportunity to be heard are provided.
    And Rovalma has identified nothing in the statute that
    forbids the Board to follow the principle, which is well
    established in other adjudicatory settings, that a tribunal
    may use a party’s own submissions against it, even if the
    opposing party bears the burden of persuasion. See, e.g.,
    Advanced Magnetic Closures, Inc. v. Rome Fastener Corp.,
    
    607 F.3d 817
    , 832 (Fed. Cir. 2010) (“To the extent that the
    district court relied on Mr. Riceman’s testimony to explain
    Mr. Bauer’s motives for listing himself as the ’773 patent
    inventor, . . . we find this error harmless because [the
    patent owner’s] own evidence . . . provided a sufficient
    basis on which to infer that Mr. Bauer intended to deceive
    the PTO.”); Nobelpharma AB v. Implant Innovations, Inc.,
    
    141 F.3d 1059
    , 1065 (Fed. Cir. 1998) (“[T]he district court
    did not place the burden of proving validity on [the patent
    owner]; [the patent owner’s] own evidence was clear and
    ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG        15
    convincing that the patent is invalid.”); Mroz v. Dravo
    Corp., 
    429 F.2d 1156
    , 1163 (3d Cir. 1970) (“It is true that
    the burden of proof is on the defendant to prove contribu-
    tory negligence. But . . . contributory negligence may . . .
    be established by the plaintiff’s evidence alone.”).
    SAS Institute, on which we relied in Magnum Oil for
    the statement invoked by Rovalma, also supports a nar-
    rower reading of Magnum Oil than Rovalma urges. In
    SAS Institute, we affirmed the Board’s construction of
    certain claim language, but remanded for application of
    that 
    construction. 825 F.3d at 1348
    –53. As we explained,
    remand was necessary because the Board had newly
    adopted that construction in its final written decision—
    even though the parties did not dispute the meaning of
    the construed claim language—without giving the peti-
    tioner an opportunity to argue that the claims would have
    been unpatentable under that (correct) construction. 
    Id. at 1350–53.
    The provision of a remand in SAS Institute
    cuts against Rovalma’s position regarding Magnum Oil
    and the statute. If the statute prohibited the Board from
    ever determining that a claim was unpatentable under a
    construction that the petitioner had not addressed in its
    submissions, remand would have been inappropriate in
    SAS Institute.
    For those reasons, we conclude that Rovalma has not
    shown a statutory bar, independent of whether it had
    adequate notice and opportunity to be heard, to the
    Board’s reliance on Rovalma’s submissions in determining
    what a skilled artisan would have found obvious based on
    Böhler’s prior-art references. We must therefore turn to
    Rovalma’s argument that it lacked adequate notice and
    opportunity to be heard. Before we do so, however, we
    emphasize two ways in which our conclusion in this
    subsection is limited.
    First, we have addressed Rovalma’s statutory argu-
    ment only in the context of the circumstances of this case.
    16        ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG
    We have not explored other questions about what authori-
    ty the statute might permit the Board to exercise to raise
    issues or arguments or to produce evidence sua sponte in
    an inter partes review, if it gave adequate notice and an
    adequate opportunity to be heard, as district courts may
    sometimes do in their cases. See, e.g., Day v. McDonough,
    
    547 U.S. 198
    , 205–11 (2006) (discussing a district court’s
    authority to raise certain affirmative defenses not raised
    by party); Monolithic Power Sys., Inc. v. O2 Micro Int’l
    Ltd., 
    558 F.3d 1341
    , 1346–48 (Fed. Cir. 2009) (discussing
    a district court’s authority to call and to question witness-
    es and to appoint its own expert under Fed. R. Evid. 614
    and 706 and to rely on the resulting evidence).
    Second, we have addressed and rejected only Roval-
    ma’s contention about statutory authority. We have not
    decided what regulatory or other non-statutory con-
    straints, either on the Board or on the parties, such as
    those which govern waiver or forfeiture, might apply to
    the Board’s determination of unpatentability under
    Rovalma’s claim construction. We note that, in this case,
    unlike in SAS Institute, the petitioner had clear notice
    that the Board might adopt the claim construction ulti-
    mately adopted—that construction was argued in the
    Patent Owner’s Response—yet it did not present a case
    for unpatentability under that construction when it had
    the opportunity, in its Reply. Whether Böhler committed
    a forfeiture, and whether Rovalma has preserved a forfei-
    ture contention, are among the non-statutory matters
    open for the Board to consider in the remand we order.
    2
    Under the APA, the Board must comply with certain
    procedural requirements in conducting an inter partes
    review. Notably, the Board must timely inform a patent
    owner of “the matters of fact and law asserted,” give the
    patent owner an “opportunity” for the “submission and
    consideration of facts” and “arguments,” and permit the
    ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG        17
    patent owner “to submit rebuttal evidence, and to conduct
    such cross-examination as may be required for a full and
    true disclosure of the facts.” 5 U.S.C. §§ 554(b)(3), (c),
    556(d); see, e.g., SAS 
    Inst., 825 F.3d at 1351
    ; Dell Inc. v.
    Acceleron, LLC, 
    818 F.3d 1293
    , 1301 (Fed. Cir. 2016);
    Belden Inc. v. Berk-Tek LLC, 
    805 F.3d 1064
    , 1080 (Fed.
    Cir. 2015). In applying those provisions, we have ex-
    plained that the Board “‘may not change theories in
    midstream without giving respondents reasonable notice
    of the change’ and ‘the opportunity to present argument
    under the new theory.’” 
    Belden, 805 F.3d at 1080
    (quoting
    Rodale Press, Inc. v. FTC, 
    407 F.2d 1252
    , 1256–57 (D.C.
    Cir. 1968)). The Board’s procedural obligations are not
    satisfied merely because a particular fact might be found
    somewhere amidst the evidence submitted by the parties,
    without attention being called to it so as to provide ade-
    quate notice and an adequate opportunity to be heard.
    
    NuVasive, 841 F.3d at 971
    .
    In this case, because we cannot sufficiently determine
    how the Board reached the conclusion that the challenged
    claims would have been obvious, we also cannot conclu-
    sively determine whether the Board’s actions complied
    with the APA’s procedural requirements. As discussed
    above, the Board’s decision indicates that the Board found
    that a person of ordinary skill would have appreciated
    that the claimed thermal conductivities could be achieved
    by practicing the claimed process steps, but does not
    adequately explain the basis for that finding. Because the
    asserted prior-art references concededly did not disclose
    those steps in as many words, the Board relied on Roval-
    ma’s submissions to determine that skilled artisans would
    have found the process steps obvious.
    To the extent that the Board did rely on Rovalma’s
    submissions, and drew reasonably disputable inferences
    from those submissions, Rovalma was entitled to ade-
    quate notice of and opportunity to address those infer-
    ences. But Böhler never described what inferences were
    18         ROVALMA, S.A.   v. BOHLER-EDELSTAHL GMBH & CO. KG
    to be made, as it essentially disregarded the process steps
    throughout the Board proceeding. And although the
    Board discussed the process steps extensively at the oral
    argument, that was too late in the absence of an addition-
    al adequate opportunity to be heard. See 
    Dell, 818 F.3d at 1301
    .
    Because we cannot sufficiently determine which in-
    ferences the Board drew from Rovalma’s submissions, we
    will not decide whether the Board violated Rovalma’s
    procedural rights. To make that decision, we would need
    to be able to determine what evidence the Board relied on
    to support its implicit factual findings, how the Board
    interpreted that evidence, and what inferences the Board
    drew from it. The Board’s opinion does not sufficiently
    permit such determinations. As with the substantial-
    evidence challenge, a remand is warranted on Rovalma’s
    procedural challenge. See Personal Web 
    Technologies, 848 F.3d at 991
    –94; 
    NuVasive, 842 F.3d at 1381
    –85; Ariosa
    
    Diagnostics, 805 F.3d at 1364
    –67.
    CONCLUSION
    For the foregoing reasons, we vacate the Board’s deci-
    sion and remand for further proceedings.
    No costs.
    VACATED AND REMANDED