Basf Corporation v. Enthone, Inc. ( 2018 )


Menu:
  •        NOTE: This disposition is nonprecedential.
    United States Court of Appeals
    for the Federal Circuit
    ______________________
    BASF CORPORATION,
    Appellant
    v.
    ENTHONE, INC.,
    Appellee
    ______________________
    2018-1095
    ______________________
    Appeal from the United States Patent and Trademark
    Office, Patent Trial and Appeal Board in No. IPR2016-
    00696.
    ______________________
    Decided: October 26, 2018
    ______________________
    RUSSELL BLYTHE, King & Spalding LLP, Atlanta, GA,
    argued for appellant. Also represented by HOLMES J.
    HAWKINS, III.
    ROBERT M. EVANS, JR., Stinson Leonard Street LLP,
    St. Louis, MO, argued for appellee. Also represented by
    JOHN R. SCHROEDER, KYLE G. GOTTUSO.
    ______________________
    Before DYK, WALLACH, and TARANTO, Circuit Judges.
    2                                 BASF CORP. v. ENTHONE, INC.
    WALLACH, Circuit Judge.
    Appellant BASF Corporation (“BASF”) petitioned for
    inter partes review of Enthone, Inc.’s (“Enthone”) 
    U.S. Patent No. 7,303,992
     (“the ’992 patent”). The U.S. Patent
    and Trademark Office’s (“USPTO”) Patent Trial and
    Appeal Board (“PTAB”) issued a final written decision
    “determin[ing] that BASF has not shown by a preponder-
    ance of the evidence that claims 1–15, 17–22, and 26–28
    [(‘the Challenged Claims’)] of the ’992 [p]atent are un-
    patentable” as obvious over two asserted combinations of
    prior art.    BASF Corp. v. Enthone, Inc. (BASF I),
    IPR2016-00696, 
    2017 WL 4014997
    , at *10 (P.T.A.B. Sept.
    11, 2017).
    BASF appeals. We have jurisdiction pursuant to 
    28 U.S.C. § 1295
    (a)(4)(A) (2012). We vacate and remand.
    BACKGROUND
    Entitled “Copper Electrodeposition in Microelectron-
    ics,” the ’992 patent generally relates to the field of “mi-
    croelectronics      manufacture     to    provide    electrical
    interconnection in a wide variety of applications, such
    as . . . in the manufacture of semiconductor integrated
    circuit . . . devices.” ’992 patent col. 1 ll. 13–16. Specifi-
    cally, it teaches a “method . . . for electrolytically plating
    [copper] onto a semiconductor integrated circuit substrate
    having submicron-sized interconnect features.”             
    Id.,
    Abstract. “An interconnect feature is a feature such as a
    via or trench formed in a dielectric substrate which is
    then filled with metal to yield an electrically conductive
    interconnect.” 
    Id.
     col. 1 ll. 23–25. The ’992 patent’s
    “method involves superfilling by rapid bottom-up deposi-
    tion at a superfill speed by which [copper] deposition
    [occurs] in a vertical direction from the bottoms of the
    features to the top openings of the features [and] is sub-
    stantially greater than [copper] deposition on the side
    walls.” 
    Id.,
     Abstract (emphasis added). Superfilling
    differs from conventional copper deposition methods, such
    BASF CORP. v. ENTHONE, INC.                                 3
    as conformal plating that involves filling “at an equal rate
    on all . . . surfaces,” and therefore “avoid[s] seams and
    pinching off that can result in voiding.” 
    Id.
     col. 2 ll. 9–11.
    Independent claims 1 and 17 are illustrative. Claim 1
    recites:
    A method for electroplating a copper deposit onto
    a semiconductor integrated circuit device sub-
    strate with electrical interconnect features includ-
    ing submicron-sized features having bottoms,
    sidewalls, and top openings, the method compris-
    ing:
    immersing the semiconductor integrated
    circuit device substrate including submi-
    cron-sized features having bottoms, side-
    walls, and top openings wherein said
    submicron-sized features include high as-
    pect ratio[1] features having dimensions
    such that the high aspect ratio features
    have aspect ratios of at least about 3:1 in-
    to an electrolytic plating composition com-
    prising a source of [copper] ions in an
    amount sufficient to electrolytically depos-
    it [copper] onto the substrate and into the
    electrical interconnect features and a pol-
    yether suppressor compound comprising a
    combination of propylene oxide (PO) re-
    peat units and ethylene oxide (EO) repeat
    units present in a PO:EO ratio between
    about 1:9 and about 9:1 and bonded to a
    nitrogen-containing species, wherein the
    molecular weight of the suppressor com-
    1  An aspect ratio is a ratio comparing depth to
    width. ’992 patent col. 2 l. 39.
    4                                BASF CORP. v. ENTHONE, INC.
    pound is between about 1000 and about
    30,000; and
    supplying electrical current to the electro-
    lytic composition to deposit [copper] on the
    substrate and superfill the submicron-
    sized features of rapid bottom-up deposi-
    tion at rate of growth in the vertical di-
    rection which is greater than a rate of
    growth in the horizontal direction.
    
    Id.
     col. 18 ll. 19–46. Similarly, claim 17 teaches a super-
    filling method that involves, inter alia:
    supplying electrical current to the electrolytic
    composition to deposit [copper] onto the substrate
    and superfill the submicron-sized features by rap-
    id bottom-up deposition at a vertical [copper] dep-
    osition growth rate in features from the bottoms of
    the features to the top openings of the features
    which is greater than 15 times faster than a field
    deposition growth rate on substrate surfaces out-
    side the features.
    
    Id.
     col. 20 ll. 51–58.
    DISCUSSION
    I. Standard of Review and Legal Standard
    “We review the PTAB’s factual findings for substan-
    tial evidence and its legal conclusions de novo.” Redline
    Detection, LLC v. Star Envirotech, Inc., 
    811 F.3d 435
    , 449
    (Fed. Cir. 2015) (citation omitted). “Substantial evidence
    is something less than the weight of the evidence but
    more than a mere scintilla of evidence,” meaning that “[i]t
    is such relevant evidence as a reasonable mind might
    accept as adequate to support a conclusion.” In re NuVa-
    sive, Inc., 
    842 F.3d 1376
    , 1379–80 (Fed. Cir. 2016) (inter-
    nal quotation marks and citations omitted). “If two
    inconsistent conclusions may reasonably be drawn from
    BASF CORP. v. ENTHONE, INC.                               5
    the evidence in record, the PTAB’s decision to favor one
    conclusion over the other is the epitome of a decision that
    must be sustained upon review for substantial evidence.”
    Elbit Sys. of Am., LLC v. Thales Visionix, Inc., 
    881 F.3d 1354
    , 1356 (Fed. Cir. 2018) (internal quotation marks,
    brackets, and citation omitted). We also review the
    PTAB’s decision to ensure that the decision did not consti-
    tute arbitrary and capricious agency action. See Vicor
    Corp. v. SynQor, Inc., 
    869 F.3d 1309
    , 1323 (Fed. Cir.
    2017).
    A patent claim is invalid “if the differences between
    the subject matter sought to be patented and the prior art
    are such that the subject matter as a whole would have
    been obvious at the time the invention was made to a
    person having ordinary skill in the [relevant] art
    [(‘PHOSITA’)].” 
    35 U.S.C. § 103
    (a) (2006). 2 Obviousness
    “is a question of law based on underlying findings of fact.”
    In re Gartside, 
    203 F.3d 1305
    , 1316 (Fed. Cir. 2000).
    Those underlying findings of fact include (1) “the scope
    and content of the prior art,” (2) “differences between the
    prior art and the claims at issue,” (3) “the level of ordi-
    nary skill in the pertinent art,” and (4) the presence of
    objective indicia of nonobviousness such “as commercial
    success, long felt but unsolved needs, failure of others,”
    and unexpected results. Graham v. John Deere Co. of
    Kan. City, 
    383 U.S. 1
    , 17–18 (1966); see United States v.
    2   Congress amended § 103 when it enacted the
    Leahy-Smith America Invents Act (“AIA”). Pub. L. No.
    112-29, § 3(b)(1), 
    125 Stat. 284
    , 285–87 (2011). However,
    because the application that led to the ’992 patent has
    never contained (1) a claim having an effective filing date
    on or after March 16, 2013, or (2) a reference under 
    35 U.S.C. §§ 120
    –121 or 365(c) to any patent or application
    that ever contained such a claim, the pre-AIA § 103
    applies. See id. § 3(n)(1), 125 Stat. at 293.
    6                               BASF CORP. v. ENTHONE, INC.
    Adams, 
    383 U.S. 49
    , 50–52 (1966). In assessing the prior
    art, the PTAB also “consider[s] whether a PHOSITA
    would have been motivated to combine the prior art to
    achieve the claimed invention and whether there would
    have been a reasonable expectation of success in doing
    so.” In re Warsaw Orthopedic, Inc., 
    832 F.3d 1327
    , 1333
    (Fed. Cir. 2016) (internal quotation marks, brackets, and
    citation omitted).
    II. Obviousness
    Before the PTAB, BASF asserted that two combina-
    tions of prior art rendered the Challenged Claims obvious:
    (1) 
    U.S. Patent No. 6,444,110
     (“Barstad”) in view of U.S.
    Patent Application No. 2002/0127847 (“Alling”) (J.A. 468–
    74) and BASF, Pluronic & Tetronic Block Copolymer
    Surfactants (1989) (“BASF Catalog”) (J.A. 436–67), and
    (2) U.S. Patent Application No. 2002/0043467 (“Morris-
    sey”) (J.A. 429–35) in view of Alling and the BASF Cata-
    log. See BASF I, 
    2017 WL 4014997
    , at *1. On appeal, the
    parties do not dispute the PTAB’s finding that both com-
    binations teach each limitation of the Challenged Claims.
    See 
    id.
     at *5–7. See generally Appellant’s Br.; Appellee’s
    Br. Instead, the central issue is whether, in view of
    Alling, a PHOSITA would have been motivated to replace
    either Barstad’s or Morrissey’s suppressor with the BASF
    Catalog’s Tetronic® surfactant copolymer. 3 See Appel-
    lant’s Br. 27; Appellee’s Br. 1–2.
    BASF raises two primary arguments. First, BASF
    argues the PTAB erred by applying an overly “stringent
    version” of the motivation to combine test. Appellant’s
    Br. 29; see 
    id.
     at 29–33. Second, BASF contends that
    certain of the PTAB’s findings are inadequately supported
    3   “Tetronic” is the tradename of a “tetra-functional
    block copolymer[]” produced by BASF. J.A. 441.
    BASF CORP. v. ENTHONE, INC.                               7
    or explained. See 
    id.
     at 33–40. We address each argu-
    ment in turn.
    A. The PTAB Did Not Commit Legal Error in Analyzing
    the Motivation to Combine the Prior Art References
    The PTAB found Alling did not provide the requisite
    motivation to combine the BASF Catalog’s Tetronic
    copolymer with either Barstad’s or Morrissey’s superfill-
    ing method. See BASF I, 
    2017 WL 4014997
    , at *10. The
    PTAB determined that a PHOSITA “would not have had
    any basis for predicting the effectiveness for superfilling
    of any suppressor whose structure or properties varied in
    any material respect from the suppressors that had al-
    ready been demonstrated” to be effective for superfilling,
    and that “there must be some specific motivation to
    employ specific plating bath components, given the gen-
    eral unpredictability in the field and the art.” 
    Id. at *8
    (emphasis added). BASF argues it was error for the
    PTAB to “require[] an explicit and specific disclosure in
    the prior art references” of a Tetronic copolymer used in
    superfilling. Appellant’s Br. 30 (citation omitted). Ac-
    cording to BASF, “limited unpredictability does not re-
    quire the prior art to state explicitly that the combination
    would be successful, without allowing for any reasonable
    inferences by a [PHOSITA].” 
    Id. at 31
     (citations omitted).
    By not allowing such inferences, BASF contends the
    PTAB improperly “treated a [PHOSITA] as an automaton,
    able only to understand what is set forth explicitly in a
    prior art reference.” 
    Id. at 32
    . We disagree with BASF.
    The PTAB adhered to our precedent when it consid-
    ered whether the level of unpredictability in the art
    demanded BASF demonstrate a more definite motivation
    to combine the prior art in the manner alleged within
    BASF’s petition. See BASF I, 
    2017 WL 4014997
    , at *8. In
    KSR International Co. v. Teleflex Inc., the Supreme Court
    explained “[t]he combination of familiar elements accord-
    ing to known methods is likely to be obvious when it does
    8                                BASF CORP. v. ENTHONE, INC.
    no more than yield predictable results.” 
    550 U.S. 398
    , 416
    (2007) (emphasis added). It rejected “rigid and mandato-
    ry formulas” in a motivation to combine analysis, 
    id. at 419
    , and instead employed an “expansive and flexible
    approach,” 
    id. at 415
    . KSR teaches that “the analysis
    need not seek out precise teachings directed to the specific
    subject matter of the challenged claim . . . [but instead]
    can take account of the inferences and creative steps that
    a [PHOSITA] would employ.” 
    Id. at 418
    . We have ex-
    plained that, under KSR, “predictability is a vital consid-
    eration in the obviousness analysis.” Otsuka Pharm. Co.
    v. Sandoz, Inc., 
    678 F.3d 1280
    , 1298 (Fed. Cir. 2012)
    (citing KSR, 
    550 U.S. at 421
    ). “To the extent an art is
    unpredictable, . . . KSR’s focus on these identified, pre-
    dictable solutions may present a difficult hurdle because
    potential solutions are less likely to be genuinely predict-
    able.” Eisai Co. v. Dr. Reddy’s Labs., Ltd., 
    533 F.3d 1353
    ,
    1359 (Fed. Cir. 2008) (emphases added) (internal quota-
    tion marks omitted). While it is true that “[o]bviousness
    does not require absolute predictability of success,” In re
    O’Farrell, 
    853 F.2d 894
    , 903 (Fed. Cir. 1998), the PTAB
    did not require absolute predictability. Despite some
    confusing language in the PTAB’s decision, we read its
    opinion as not departing from KSR’s holding that there
    need not be “precise teachings” of a motivation to combine
    in the prior art. 
    550 U.S. at 418
    . Instead, we read the
    PTAB’s decision as simply requiring BASF to demon-
    strate a sufficiently “apparent reason to combine the
    known elements in the fashion claimed by the patent at
    issue,” 
    id. at 418
    , in light of the record evidence of “gen-
    eral unpredictability in the field and the art,” BASF I,
    
    2017 WL 4014997
    , at *8. The PTAB was entitled to
    consider BASF’s asserted combinations of references in
    light of this unpredictability. See Eisai, 
    533 F.3d at 1359
    .
    BASF’s citation to In re Kubin does not alter our con-
    clusion. Appellant’s Br. 31 (citing 
    561 F.3d 1351
    , 1360–61
    (Fed. Cir. 2009)). In In re Kubin, we affirmed the PTAB’s
    BASF CORP. v. ENTHONE, INC.                                 9
    finding of obviousness and “decline[d] to cabin KSR to the
    ‘predictable arts’ (as opposed to the ‘unpredictable art’ of
    biotechnology).” 
    561 F.3d at 1360
    ; see 
    id. at 1361
    . How-
    ever, In re Kubin does not stand for the proposition that
    unpredictability is not relevant to the motivation to
    combine analysis. Instead, we explained that, “in the face
    of KSR, [we cannot] cling to formalistic rules for obvious-
    ness, customize its legal tests for specific scientific fields
    in ways that deem entire classes of prior art teachings
    irrelevant, or discount the significant abilities of [PHOSI-
    TAs] in an advanced area of art.” 
    Id. at 1360
    . Therefore,
    we looked to the record to determine whether a PHOSITA
    would find the “claimed results profoundly predictable.”
    
    Id.
     (internal quotation marks omitted). Contrary to
    BASF’s argument that the PTAB’s approach of requiring
    a more definitive motivation to combine is overly “strin-
    gent,” Appellant’s Br. 29, this approach fits within the
    Supreme Court’s directive to “account [for] the inferences
    and creative steps that a [PHOSITA] would employ,”
    KSR, 
    550 U.S. at 418
    , by considering whether, based on
    the record, the level of unpredictability in the art would
    affect such inferences and creative steps, such that a
    PHOSITA might require a more explicit directive, see
    BASF I, 
    2017 WL 4014997
    , at *8. We conclude that the
    PTAB did not apply an incorrect legal standard in its
    motivation to combine analysis, and we therefore turn to
    whether the PTAB’s findings are supported by substantial
    evidence.
    B. Important PTAB Findings Regarding Its Holding of
    Nonobviousness Either Lack Support in the Cited Evi-
    dence or Are Inadequately Explained
    The PTAB found that a PHOSITA would understand
    “the differences between [conventional,] conformal plating
    and superfilling electrolytic plating,” and “would have
    appreciated that it was unpredictable whether a given
    molecule would have served as a suppressor effective for
    superfilling.” 
    Id. at *5
    . According to the PTAB, a
    10                               BASF CORP. v. ENTHONE, INC.
    PHOSITA would not know, without any additional direc-
    tion, “that Alling would have had specific utility to super-
    filling.” 
    Id. at *8
    . BASF argues the PTAB erred by, inter
    alia, (1) failing to support its finding that Alling has no
    application to superfilling, Appellant’s Br. 42–45; and
    (2) reaching inconsistent conclusions, in two separate
    inter partes reviews, regarding whether Barstad discloses
    Tetronic copolymers as suppressors in superfilling, 
    id.
     at
    48–50. We agree with BASF.
    1. Alling’s Application to Superfilling
    The PTAB failed to support its finding that a
    PHOSITA would not have found Alling applicable to
    superfilling. Barstad and Morrissey each teach a method
    of superfilling that utilizes a suppressor. See Barstad
    col. 6    ll. 5–8    (stating   “use   of    a    suppressor
    agent . . . provides surprisingly enhanced plating perfor-
    mance, particularly in bottom-fill plating”); J.A. 430
    (providing, in Morrissey, that additives such as “suppres-
    sor compounds” are used “particularly . . . in copper
    electroplating baths designed to provide superfill of small
    apertures”). Both references teach superfilling that may
    be used to plate high aspect ratio vias or trenches, with
    diameters of about 200 nanometers. See Barstad col. 7
    l. 66–col. 8 l. 1 (explaining that “aspect ratios of at least
    4:1, having diameters of about 200 [nanometers] or small-
    er have been effectively copper plated with no defects,”
    such as “voids”); J.A. 433 (stating, in Morrissey, that
    “aspect ratios of at least 4:1, having diameters of about
    200 [nanometers] or smaller have been effectively copper
    plated with no defects,” including “voids”). Alling teaches
    that “chip interconnects are required at critical dimen-
    sions of 200 [nanometers] or less,” J.A. 469, and that
    copolymers, such as those “sold by BASF under [the]
    Tetronic . . . tradename[],” may be used as “suppressor
    agents for plating compositions,” J.A. 472.
    BASF CORP. v. ENTHONE, INC.                               11
    The PTAB determined that a PHOSITA would not
    understand Alling as relating to superfilling because “the
    mentioning of chip interconnects at dimensions of 200
    [nanometers] and less in Alling would not have informed
    [a PHOSITA] that Alling would have had specific utility
    to superfilling because those specific dimensions could
    effectively receive electrodeposition without superfilling.”
    BASF I, 
    2017 WL 4014997
    , at *8 (citing J.A. 1029–30).
    The PTAB cited no support except one passage in En-
    thone’s expert declaration. See 
    id.
     But nothing in the
    cited portion of that declaration supports the proposition
    that chip interconnects at dimensions of 200 nanometers
    or less could be effectively plated without superfilling. See
    J.A. 1029–30 (acknowledgment, by Enthone’s expert, that
    Alling references chip interconnects at dimensions of 200
    nanometers or less, but stating “beyond that the reference
    offers no description of or allusion to filling submicron
    features,” nor does it explicitly mention superfilling). At
    oral argument, Enthone admitted that the PTAB failed to
    support its finding.          Oral Arg. at 16:41–19:22,
    http://oralarguments.cafc.uscourts.gov/default.aspx?fl=
    2018-1095.mp3 (Q: “I’m struck by what appears to be,
    first of all, a mis-citation on [J.A.] 21–22, where [the
    PTAB] reject[s] this argument that the dimensions dis-
    closed in Alling necessarily require superfilling, and they
    say no that’s not true ‘because those specific dimensions
    could effectively receive electrodeposition without super-
    filling,’ and they cite [J.A.] 2031 and paragraph 69 for
    that proposition. . . . [T]hat paragraph . . . does not sup-
    port what the [PTAB] says about it.” A: “That statement
    is not in [paragraph] 69.”).
    The PTAB’s failure to provide “an adequate eviden-
    tiary basis for its findings” renders its motivation to
    combine analysis insufficient. In re NuVasive, 842 F.3d at
    1382 (internal quotation marks and citation omitted).
    Indeed, this determination served as the PTAB’s basis to
    disregard other, conflicting deposition testimony from
    12                                BASF CORP. v. ENTHONE, INC.
    Enthone’s expert that appears to support BASF’s position.
    See J.A. 946 (Q: “[S]uccessfully plating copper and chip
    interconnects of 200 nanometers [or] less is going to
    involve superfilling, correct?” A: “For those interconnects
    of that dimension, 200 nanometers or less, yes. For larger
    interconnects perhaps not.”); see also BASF I, 
    2017 WL 4014997
    , at *8 (accepting this testimony as “correct,” but
    ultimately crediting Enthone’s expert declaration). Ac-
    cordingly, we vacate and remand to the PTAB to recon-
    sider whether either of the asserted combinations of prior
    art provide the requisite motivation to combine, in light of
    the discussion of Alling above.
    2. Inconsistent Findings Regarding Barstad
    “[T]he PTAB must examine the relevant data and ar-
    ticulate a satisfactory explanation for its action including
    a rational connection between the facts found and the
    choice made.” In re NuVasive, 842 F.3d at 1382 (internal
    quotation marks and citation omitted). “This explanation
    enables the court to exercise its duty to review the PTAB’s
    decisions to assess whether those decisions are arbitrary,
    capricious, an abuse of discretion, or unsupported by
    substantial evidence.” Id. (internal quotation marks,
    ellipses, and citation omitted).
    The PTAB acted arbitrarily and capriciously by failing
    to provide a reasoned explanation for reaching an incon-
    sistent finding regarding Barstad. Barstad states that, in
    general, electroplating solutions may contain additives
    “such as surfactants, brighteners, levelers[,] and suppres-
    sants.” Barstad col. 1 ll. 24–25. Barstad teaches that
    “preferably the plating bath [of the invention] . . . contains
    a surfactant-type suppressor agent,” and that “such a
    suppressor agent in combination with elevated brightener
    concentrations can result in effective ‘bottom-fill’ copper
    plating of a microvia or other aperture without defects
    such as inclusions or voids.” Id. col. 3 ll. 20–25. In an
    inter partes review of 
    U.S. Patent No. 7,815,786
     (“the ’786
    BASF CORP. v. ENTHONE, INC.                               13
    patent”) 4 involving the same parties and asserted combi-
    nations of prior art, the PTAB found the challenged
    claims obvious, determining that “Barstad discloses
    polyethylene glycol copolymers as preferable surfactant-
    type suppressor agents, and expressly discloses the poly-
    ethylene glycol copolymers that were commercially avail-
    able from BASF under the Tetronic tradename.” BASF
    Corp. v. Enthone, Inc. (BASF II), IPR2016-00697, 
    2017 WL 4015000
    , at *7 (P.T.A.B. Sept. 11, 2017) (emphasis
    added) (internal quotation marks and citation omitted).
    Here, the PTAB determined that Barstad discloses
    Tetronic copolymers as surfactants, and therefore they
    cannot be suppressors, because Barstad “describes sup-
    pressors and surfactants as separate components of the
    electrodeposition bath.” BASF I, 
    2017 WL 4014997
    , at *8
    (internal quotation marks and citation omitted); see 
    id.
    (disagreeing with BASF that “Barstad implies that
    Tetronic[] copolymers may be used as suppressors”).
    The PTAB’s finding that Barstad teaches that sup-
    pressors and surfactants are separate is, therefore, plain-
    ly inconsistent with the PTAB’s finding in the inter partes
    review of the ’786 patent that Barstad teaches a Tetronic
    copolymer acting as a surfactant-type suppressor agent.
    Compare BASF II, 
    2017 WL 4015000
    , at *7, with BASF I,
    
    2017 WL 4014997
    , at *8. This inconsistency is critical
    4    The application that led to the ’786 patent was
    filed as a divisional of the application that led to the ’992
    patent. “[A] divisional application contains an identical
    disclosure to its parent application” and “is defined as a
    later application for an independent or distinct invention,
    carved out of a pending application and disclosing and
    claiming only subject matter in the earlier or parent
    application.” Pfizer, Inc. v. Teva Pharm. USA, Inc., 
    518 F.3d 1353
    , 1359, 1360 (Fed. Cir. 2008) (internal quotation
    marks, brackets, and citation omitted).
    14                                BASF CORP. v. ENTHONE, INC.
    because, if the PTAB finds Barstad teaches a Tetronic
    copolymer may be used as a suppressor in superfilling,
    such a finding would be highly relevant to obviousness.
    See BASF I, 
    2017 WL 4014997
    , at *8 (requiring “some
    specific motivation to employ specific plating bath compo-
    nents, given the general unpredictability in the field and
    the art” (emphasis added)). Rather than providing a
    satisfactory explanation for its divergent findings, the
    PTAB simply rejected BASF’s argument “that Barstad
    does not contain the clear delineation between suppres-
    sors and surfactants,” by stating it was “not persuaded
    that Barstad does not disclose each distinctly.” 
    Id.
     (inter-
    nal quotation marks and citation omitted). Absent “any
    reasoned explanation for th[is] inconsistent result” be-
    tween the two inter partes reviews, we find it appropriate
    to vacate and remand so the PTAB may reevaluate
    whether Barstad discloses Tetronic copolymers as sup-
    pressors for use in superfilling. Vicor, 869 F.3d at 1323;
    see id. (vacating and remanding where the PTAB failed to
    provide any reasoned explanation for reaching directly
    conflicting obviousness conclusions in two reexaminations
    involving closely-related subject matter).
    CONCLUSION
    We have considered the parties’ remaining arguments
    and find them unpersuasive. Accordingly, the Final
    Written Decision of the U.S. Patent and Trademark
    Office’s Patent Trial and Appeal Board is
    VACATED AND REMANDED
    COSTS
    No costs.