Rozbicki v. Chiang , 590 F. App'x 990 ( 2014 )


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  •        NOTE: This disposition is nonprecedential.
    United States Court of Appeals
    for the Federal Circuit
    ______________________
    ROBERT ROZBICKI, MICHAL DANEK, AND
    ERICH KLAWUHN,
    Appellants,
    v.
    TONY CHIANG, GONGDA YAO, PEIJUN DING,
    FUSEN E. CHEN, BARRY L. CHIN, GENE Y.
    KOHARA, ZHENG XU, AND HONG ZHANG,
    Appellees.
    ______________________
    2014-1041
    ______________________
    Appeal from the United States Patent and Trademark
    Office, Patent Trial and Appeal Board in Interference No.
    105,898.
    ______________________
    Decided: November 14, 2014
    ______________________
    TODD R. WALTERS, Buchanan Ingersoll & Rooney PC,
    of Alexandria, Virginia, argued for appellants. With him
    on the brief were S. LLOYD SMITH and ERIN M. DUNSTON.
    JOHN R. KENNY, Kenyon & Kenyon LLP, of New York,
    New York, argued for appellees. With him on the brief
    were MARIA LUISA PALMESE and JOSEPH A. COPPOLA. Of
    counsel was GAUDENIS VIDUGIRIS.
    2                                       ROZBICKI   v. CHIANG
    ______________________
    Before DYK and O’MALLEY, Circuit Judges. *
    O’MALLEY, Circuit Judge.
    This patent appeal arises from an interference pro-
    ceeding before the United States Patent and Trademark
    Office Patent Trial and Appeal Board (“PTAB”) relating to
    technology for depositing and etching barrier materials on
    wafer substrates. The PTAB construed the term “etching”
    as “the removal of material to create a pattern.” Relying
    on this construction, the PTAB found that U.S. Patent
    Application No. 11/733,671 (“the Chiang Application”)
    contained adequate written description support for the
    lone interference count.
    On appeal, Rozbicki challenges the PTAB’s construc-
    tion of “etching” and its written description finding.
    Because we agree with the PTAB’s claim construction, we
    affirm its written description decision for Chiang claims
    31–39, 46, 59–61, 63, 64, 66–71, 83, and 84 as it is sup-
    ported by substantial evidence. We vacate and remand
    the PTAB’s decision for Chiang claims 47, 49, 51, 53, 55,
    57, 76–82, 85, 87, 88, and 90, however, because we find
    that the PTAB’s explanation of how the Chiang Applica-
    tion describes the “net etching” limitation is inadequate.
    BACKGROUND
    This technology relates to wafer substrates to make
    integrated circuits. The wafer substrates contain semi-
    conductor devices that are electrically connected to form
    the integrated circuits. Appellee Br. 4. These electrical
    connections are made using vias, which are openings in a
    *   Randall R. Rader, who retired from the position of
    Circuit Judge on June 30, 2014, did not participate in this
    decision.
    ROZBICKI   v. CHIANG                                      3
    layer of silicon dioxide above the wafer substrate. 
    Id. These vias
    are filled with metal to make the electrical
    connections. 
    Id. Previously, semiconductor
    manufactur-
    ers used aluminum to make these electrical connections.
    
    Id. Eventually, manufacturers
    switched to copper, which
    has a lower resistivity. 
    Id. This switch,
    however, re-
    quired the placement of a layer of barrier material be-
    tween the silicon dioxide and the copper to prevent the
    copper from diffusing into the silicon dioxide. 
    Id. Nor- mally,
    this barrier material is placed over the silicon
    dioxide through a physical vapor deposition process, such
    as, sputtering or a chemical vapor deposition pro-
    cess. ’977 Patent col. 2 ll. 13–16. Sputtering is a process
    where atoms are ejected from a solid target material
    towards a substrate by bombarding the target material
    with energetic particles. Resputtering is the sputtering of
    previously deposited material. Typical barrier materials
    can include tantalum, tantalum nitride, tungsten, titani-
    um, titanium tungsten, titanium nitride, etc. ’977 Patent
    col. 2 ll. 11–13. The identical claims-at-issue on appeal
    from both disclosures are directed to a method of deposit-
    ing barrier material.
    U.S. Patent No. 6,607,977 (“the ’977 Patent” or “the
    Rozbicki Patent”) issued on August 19, 2003. It is titled
    “Method of Depositing a Diffusion Barrier for Copper
    Interconnect Applications.” ’977 Patent, at [54] (filed
    September 26, 2001). As shown in Figure 3C below, the
    invention discloses a first step of depositing barrier mate-
    rial 325 to provide coverage, then a second step of deposit-
    ing additional barrier material and simultaneously
    etching a portion of the barrier material deposited in the
    first step as seen in Figure 3D.
    4                                        ROZBICKI   v. CHIANG
    ’977 Patent Fig. 3C, 3D. The summary of the invention
    states that the result of the steps is a metal diffusion
    barrier formed in part by “net etching” in the bottom of
    the vias and “net deposition” on the side walls. The
    specification describes “net etching” as having an “etch to
    deposition ratio” or “E/D” that is greater than 1. The
    purpose of this “net etching” is to reduce the resistance of
    subsequently formed metal interconnects.
    The Chiang Application relates to “a method of sput-
    tering a sculptured coating over the walls of a high aspect
    ratio semiconductor feature in a manner which avoids or
    significantly reduces the possibility of damage to or
    contamination of underlying surfaces.” Joint Appendix
    (“J.A.”) 1180. The Chiang Application generally describes
    applying a first portion of a sculptured layer using tradi-
    tional sputtering or ion deposition sputtering with a low
    substrate bias such that a surface onto which said sculp-
    tured layer is applied is not eroded away. J.A. 1188. It
    then describes applying a subsequent portion of the
    sculptured layer using ion deposition sputtering with
    sufficiently high substrate bias to sculpture a shape from
    said first portion while depositing additional layer mate-
    rial. J.A. 1188. Chiang explains that, “[a]fter deposition
    ROZBICKI   v. CHIANG                                        5
    of a first portion of barrier layer material, the bias voltage
    is increased during the deposition of additional barrier
    layer material over the feature surface. The application
    of increased bias voltage results in the resputtering
    (sculpturing) of the first portion of barrier layer or wetting
    layer material (deposited at the lower substrate bias
    voltage) while enabling a more anisotropic deposition of
    newly depositing material.” J.A. 1190. “Availability of
    the material which was deposited at the lower bias volt-
    age on the surface of a trench or via protects the substrate
    surface under the barrier or wetting layer material during
    the sputtering deposition at higher bias voltage. This
    avoids breakthrough into the substrate by impacting
    ionized material which could destroy device functionality.”
    J.A. 1190.
    Chiang provides three examples in his application,
    which correspond to the Chiang Application Figures 3 to
    5. The key example is Example 3, describing Figure 5.
    6                                         ROZBICKI   v. CHIANG
    This figure discloses an embodiment involving an ini-
    tial deposition where a barrier material is applied for 15
    seconds without the application of substrate biasing
    power, then applying a substrate biasing power of -60V
    (250W) while depositing barrier material through ion
    deposition plasma for about 45 seconds. J.A. 1200–01.
    During this second deposition period, barrier material
    from the first deposition period is resputtered, with excess
    barrier material being removed and reshaped. J.A. 1201.
    On May 25, 2012, the PTAB declared Interference No.
    105,898 between claims 1–73 of the Rozbicki Patent and
    claims 31–90 of the Chiang Application. As Chiang copied
    its claim language from the Rozbicki Patent, the interfer-
    ence included a single count: claim 1 of the ’977 Patent
    which is the same as claim 31 of the Chiang Application.
    These identical claims state:
    A method for depositing a diffusion barrier and a
    metal conductive layer for metal interconnects on
    a wafer substrate, the method comprising:
    (a) depositing a first portion of the diffusion barri-
    er over the surface of the wafer substrate;
    (b) etching the first portion of the diffusion barrier
    at the bottom of a plurality of vias without fully
    etching through such that an amount of barrier
    material remains at the bottom of the plurality of
    vias, while depositing a second portion of the dif-
    fusion barrier elsewhere on the wafer substrate;
    and
    (c) depositing the metal conductive layer over the
    surface of the wafer substrate such that the metal
    conductive layer contacts the barrier material re-
    maining at the bottom of the plurality of vias;
    wherein at least part of (a) and all of (b) are per-
    formed in the same processing chamber.
    ROZBICKI   v. CHIANG                                       7
    J.A. 155–166, 178–187 (emphasis added); see also ’977
    Patent col. 14 ll. 24–41. For the lone count, the PTAB
    accorded Rozbicki benefit back to March 13, 2001, and
    Chiang back to November 26, 1997. Accordingly, the
    PTAB deemed Rozbicki the junior party and Chiang the
    senior party.
    Rozbicki filed a first motion for judgment asserting
    that the Chiang Application failed to satisfy the written
    description requirement. Rozbicki further filed a second
    motion for judgment that Chiang is not entitled to the
    benefit of the filing date of any earlier application because
    those applications also fail to satisfy the written descrip-
    tion requirement. Chiang filed a motion to exclude cer-
    tain evidence. 1 On June 26, 2013, the PTAB: (1) granted-
    in-part Rozbicki’s motion for failure to meet written
    description for Chiang claims 40–45, 48, 50, 2 52, 54, 56,
    58, 62, 65, 72–75, 86, and 89, 3 but denied-in-part for
    Chiang claims 31–39, 46, 47, 49, 51, 53, 55, 57, 59–61, 63,
    64, 66–71, 76–85, 87, 88, and 90; (2) denied Rozbicki’s
    second motion on accorded benefit; and (3) granted-in-part
    and denied-in-part Chiang’s motion to exclude certain
    evidence.
    1   Chiang moved to exclude certain statements from
    Rozbicki’s patent and priority application that are repeat-
    ed in the Rozbicki expert’s testimony as hearsay. The
    PTAB denied this motion on the grounds that the docu-
    ments were admissible as proof of what they say. Accord-
    ingly, Rozbicki’s expert was allowed to reasonably rely on
    these documents. This ruling is not at issue on appeal.
    2   While the PTAB granted Rozbicki’s motion as to
    claim 50, that claim was not included in the PTAB’s
    summary of dismissed claims. Compare J.A. 19, with J.A.
    20.
    3   Chiang is not appealing the PTAB’s finding for
    these dependent claims.
    8                                         ROZBICKI   v. CHIANG
    Addressing the construction of “etching,” the PTAB
    construed the term as requiring “the removal of material
    to create a pattern.” J.A. 7. The PTAB then found that
    the Chiang Application disclosed sputtering/resputtering
    as one way to etch and deposit simultaneously, and point-
    ed to Example 3 for disclosing the necessary etching. The
    PTAB further found that Chiang taught “net etching”
    based on Example 3. J.A. 15. As essentially the same
    reasons regarding written description, the PTAB found
    priority for Chiang.
    Rozbicki subsequently filed a motion for rehearing.
    On July 16, 2013, the PTAB entered its Decision on
    Request for Rehearing. While the PTAB reconsidered the
    decision, it denied the requested relief. The PTAB stated
    that there was nothing that compelled a narrower claim
    interpretation. The PTAB stated that the claims only
    require “etching,” not “net etching” as described in the
    Rozbicki Patent’s written description.         Turning to
    Chiang’s disclosure, the PTAB stated that Chiang’s Ex-
    ample 3 made sense only if etching occurred in the second
    step. The PTAB also stated that it found Rozbicki’s
    expert less credible than Chiang’s expert. It then ex-
    plained that the independent claims did not require
    reducing thickness of the barrier layer and that, even if
    they did, Chiang’s second step appears to reduce the
    thickness while redistributing the material.
    On July 30, 2013, the PTAB entered Judgment find-
    ing that Rozbicki did not have priority, and, consequently,
    cancelled claims 1–73 of the ’977 Patent. Rozbicki timely
    appealed. This court has jurisdiction pursuant to 28
    U.S.C. § 1295.
    DISCUSSION
    A. Claim Construction
    This court reviews claim construction de novo. Light-
    ing Ballast Control LLC v. Philips Elecs. N. Am., 744 F.3d
    ROZBICKI   v. CHIANG                                     9
    1272, 1276–77 (Fed. Cir. 2014) (en banc). “[W]hen a party
    challenges written description support for an interference
    count or the copied claim in an interference, the originat-
    ing disclosure provides the meaning of the pertinent claim
    language.” Agilent Techs., Inc. v. Affymetrix, Inc., 
    567 F.3d 1366
    , 1375 (Fed. Cir. 2009); see also In re Spina, 
    975 F.2d 854
    , 856 (Fed. Cir. 1992) (“When interpretation is
    required of a claim that is copied for interference purpos-
    es, the copied claim is viewed in the context of the patent
    from which it was copied.” (citing DeGeorge v. Bernier, 
    768 F.2d 1318
    , 1322 (Fed. Cir. 1985))). Consequently, we
    review the Chiang claims copied from the Rozbicki Patent
    in light of the Rozbicki Patent specification. See 
    Agilent, 567 F.3d at 1375
    .
    The PTAB construed the term “etching” as the remov-
    al of barrier material. Looking at the claim language
    itself, the PTAB stated that the claim “simply requires
    ‘etching’.” J.A. 6. It emphasized that Rozbicki defines
    “net etching” in its written description, but only refer-
    ences “etching” in the independent claims. The PTAB
    pointed out that this supports an inference that the
    claims are broader than the preferred embodiment.
    Turning to the expert testimony presented by both par-
    ties, the PTAB found the testimony of Chiang’s expert,
    Dr. Cuomo, more credible than that of Rozbicki’s expert,
    Dr. Ruzic, with respect to what the term “etching” re-
    quires. Specifically, the PTAB found Dr. Ruzic’s testimo-
    ny less credible because the term “net etching” is not an
    art-recognized term and introduces imprecision. J.A. 6.
    Rozbicki argues that the PTAB erred in ruling that
    “etching” does not require “net etching”—which occurs
    when there is more etching than deposition—in all the
    claims. He further argues that the PTAB should have
    construed etching to require thinning of the barrier layer
    at the bottom of the via. Rozbicki also asserts that the
    PTAB defined etching without considering the Rozbicki
    specification. He points out that the specification “re-
    10                                       ROZBICKI   v. CHIANG
    peatedly, consistently, and exclusively” teaches reducing
    the thickness of the barrier layer previously deposited at
    the bottom of the via. Chiang responds that the PTAB
    correctly construed the term etching as simply the remov-
    al of barrier material. He agrees with the PTAB that the
    claim language in the independent claims only requires
    “etching,” and not any particular level of etching. Chiang
    further states that the specification describes net deposi-
    tion where the etch to deposition ratio is less than one,
    which refutes the requirement that etching requires “net
    etching” or “net removal.” ’977 Patent col. 13 ll. 13–19
    (“The magnitude of E/D on the side walls is < 1 . . . . The
    side walls receive a net deposition.”).
    We agree with Chiang that the PTAB properly de-
    fined etching to require the removal of material, and not
    “net etching” or thinning at the bottom of the via. The
    claim language states “(b) etching the first portion of the
    diffusion barrier at the bottom of a plurality of vias with-
    out fully etching through such that an amount of barrier
    material remains at the bottom of the plurality of vi-
    as.” ’977 Patent col. 14 ll. 30–33. The claim language
    itself does not include any requirement of “net etching” or
    thinning at the bottom of the via.
    Rozbicki improperly attempts to read limitations into
    the claims based on the embodiments described in his
    written description, limitations which are absent from the
    claim language. The Rozbicki Patent’s written descrip-
    tion, however, explicitly describes “net etching” as having
    an etch to deposition ratio of greater than 1. Accordingly,
    even Rozbicki recognizes that this “net etching” is distin-
    guishable from the term “etching.” For example, Rozbicki
    claim 27, which corresponds to Chiang claim 47, states:
    “wherein (b) comprises a PVD etch/deposition process in
    which an RF frequency is applied to the wafer substrate
    such that the etch to deposition ratio is greater than 1 in
    the bottom of the plurality of vias and less than 1 on the
    field.” ’977 Patent col. 15 ll. 44–48 (emphasis added).
    ROZBICKI   v. CHIANG                                    11
    First, this claim language uses the term “etch” as part of
    its description of “net etching” for the bottom of the plu-
    rality of vias. Second, this very same claim requires an
    etch to deposition ratio less than 1 on the field. If the
    term “etching” required “net etching,” then an etch to
    deposition ratio less than 1 would not make any sense, or
    at least be redundant. Accordingly, this claim language
    supports the PTAB’s broader construction of the term
    “etching.” Furthermore, despite the ability to include the
    term “net etching” or an etch to deposition ratio greater
    than 1 in the text of its claims, Rozbicki chose to include
    only the term “etching” in its independent claims. Chiang
    then copied this broad language into his own claims.
    Rozbicki, while attempting to obtain the broadest claim
    language possible during prosecution, cannot now im-
    properly narrow its language by importing limitations not
    supported by the claim language or written description.
    For the reasons above, we affirm the PTAB’s claim con-
    struction of “etching.”
    B. Written Description Requirement
    1. Etching
    Rozbicki disputes whether the Chiang Application
    provides written description support for the claims-at-
    issue. The written description requirement is found in 35
    U.S.C. § 112 (2012), which states:
    The specification shall contain a written descrip-
    tion of the invention, and of the manner and pro-
    cess of making and using it, in such full, clear,
    concise, and exact terms as to enable any person
    skilled in the art to which it pertains, or with
    which it is most nearly connected, to make and
    use the same, and shall set forth the best mode
    contemplated by the inventor or joint inventor of
    carrying out the invention.
    12                                       ROZBICKI   v. CHIANG
    To satisfy the written description requirement, the
    specification must “convey with reasonable clarity to
    those skilled in the art that, as of the filing date sought,
    he or she was in possession of the [claimed] invention.”
    Vas-Cath, Inc. v. Mahurkar, 
    935 F.2d 1555
    , 1563–64 (Fed.
    Cir. 1991). The properly construed claim must be sup-
    ported by the originating specification. 
    Agilent, 567 F.3d at 1378
    –79. Satisfying the written description require-
    ment is a question of fact that we review for substantial
    evidence. Harari v. Lee, 
    656 F.3d 1331
    , 1341 (Fed. Cir.
    2011) (citing Chen v. Bouchard, 
    347 F.3d 1299
    , 1304 (Fed.
    Cir. 2003)).
    In light of its claim construction of “etching,” the
    PTAB concluded that the Chiang Application sufficiently
    described this limitation, which is recited in Chiang
    independent claims 31 and 66. Specifically, the PTAB
    found the Chiang Application’s discussion of the sputter-
    ing/resputtering process, which removes barrier material
    at the bottom of the via, satisfied the written description
    requirement for “etching.” In support, it looked to Exam-
    ple 3 in light of Examples 1 and 2 from the Chiang Appli-
    cation. The PTAB explained that the three examples “are
    sufficient to indicate to one of ordinary skill that, more
    likely than not, the third example achieves its purported
    result by offsetting the results of method steps similar to
    example 2 with the results of method steps similar to
    example 1.” J.A. 11. The PTAB also relied on the testi-
    mony of Chiang’s expert, Dr. Cuomo, who explained that
    etching results from the biasing substrate, which creates
    an electrical field, causing ions to impact on the silicon
    substrate and silicon dioxide sidewall, resulting in simul-
    taneous sputtering of the surfaces such as through the
    second step of Example 3.
    Rozbicki argues that the Chiang Application does not
    satisfy the written description requirement. According to
    Rozbicki, the written description does not make clear that
    etching occurs at the bottom of the via, and Example 3
    ROZBICKI   v. CHIANG                                    13
    does not necessarily show etching. Chiang responds that
    substantial evidence exists based on Example 3 and Dr.
    Cuomo’s expert testimony, which the PTAB found more
    credible than that of Rozbicki’s expert. Since we agree
    with the PTAB’s claim construction, we look to see if the
    PTAB’s finding that the Chiang Application sufficiently
    described the “etching” limitation is supported by sub-
    stantial evidence. We find that it is, and do not find
    Rozbicki’s arguments persuasive.
    The Chiang Application generally discloses the re-
    moval of material through sputtering/resputtering. It
    then provides a step for “applying a subsequent portion of
    said sculptured layer using ion deposition sputtering,
    with sufficiently high substrate bias to sculpture a shape
    from said first portion, while depositing additional layer
    material.” J.A. 1188. During this step, “[t]he application
    of increased bias voltage results in the resputtering
    (sculpturing) of the first portion of barrier layer.” J.A.
    1190; see also J.A. 1201. Consequently, the barrier layer
    from the first deposition period, which includes the barri-
    er layer at the bottom of the via, is resputtered. This
    resputtering meets the “etching” requirement.
    Chiang’s expert, Dr. Cuomo, testified that the sputter-
    ing/resputtering removes sections of the initially deposit-
    ed barrier layer from the bottom of the via. In particular,
    he pointed to Example 3 as reproduced from Figure 5 of
    the Chiang Application.
    14                                      ROZBICKI   v. CHIANG
    Dr. Cuomo testified that Example 3 discloses the
    claimed invention, and essentially performs the steps of
    Example 2 and then Example 1 consecutively, in that
    order. J.A. 2635–40. Example 1 discloses etching as seen
    by the breakthrough in the barrier level when sputtering
    with a substrate bias. Example 2 discloses sputtering
    with no substrate bias, resulting in the deposit of a large
    quantity of barrier material at the bottom of the via with
    no breakthrough. By performing a first step similar to
    Example 2 prior to the step of Example 1, Chiang’s expert
    testified that Example 3 prevents breakthrough into the
    lower level when etching occurs during the second step
    similar to Example 1. J.A. 2639. Furthermore, the
    Chiang Application explains that the first deposit layer
    “protects the substrate surface . . . during the sputtering
    deposition at higher bias voltage” and “avoids break-
    through.” J.A. 1190. This concern exists only if the
    second step causes etching. Based on the specification of
    the Chiang Application and the expert testimony, there is
    ROZBICKI   v. CHIANG                                     15
    substantial evidence to support the conclusion that the
    Chiang Application discloses etching.
    Rozbicki also argues that the Chiang Application only
    employs two sequential deposition steps, not an etching
    step of the layer at the bottom of the via. In support, he
    points to language in the Chiang Application stating that
    the steps listed are described as depositing steps for a
    barrier layer substance. 4 Chiang disagrees, stating that
    the second step in its application inherently includes
    etching within the depositing step. As explained by the
    PTAB and Chiang’s expert, although the Chiang Applica-
    tion lists its steps as depositing steps, this does not
    change the fact that the second step in the Chiang Appli-
    cation also performs etching.
    Rozbicki contends that the PTAB erred because the
    disclosure of sputtering/resputtering does not provide
    support for the full scope of the term “etching” in Chiang’s
    claims. In Rozbicki’s first motion, he requested “judgment
    that Chiang’s involved claims are unpatentable to Chiang
    under 35 U.S.C. § 112, first paragraph, as lacking ade-
    quate written description.” J.A. 412. The PTAB found
    that Rozbicki did not advance a scope argument, instead
    arguing only that the Chiang Application failed to de-
    scribe a particular embodiment. J.A. 22. The PTAB
    addressed this point again in its decision on request for
    rehearing. It stated that, “[w]hile the statute encom-
    passes a scope argument, it does not follow that Rozbicki
    necessarily made a scope argument. As the decision
    noted, case law distinguishes scope as a distinct type of
    4    The specific claim language for the second step
    states: “applying a subsequent portion of said sculptured
    layer using ion deposition sputtering, with sufficiently
    high substrate bias to sculpture a shape from said first
    portion, while depositing additional layer material.” J.A.
    1188.
    16                                        ROZBICKI   v. CHIANG
    written description problem.” J.A. 40. It further stated
    that, “[a]s a matter of due process, Chiang need not
    address every theory that Rozbicki could have argued, but
    only the argument Rozbicki actually made.” J.A. 40
    (footnote omitted). We agree with the PTAB that Rozbicki
    did not properly raise a scope argument before the PTAB,
    and thus, we find that the PTAB did not err in failing to
    address this argument.
    Because substantial evidence supports the PTAB’s
    finding that the Chiang Application adequately describes
    the “etching” limitation, we affirm the PTAB’s finding
    that Chiang claims 31 and 66 meet the written descrip-
    tion requirement.      Additionally, since Rozbicki only
    argues that Chiang dependent claims 32–39, 46, 59–61,
    63, 64, 67–71, 83, and 84 do not meet the written descrip-
    tion requirement because the Chiang Application fails to
    disclose the “etching” limitation—the same argument we
    just rejected—we also affirm the PTAB’s findings as to
    these claims. Furthermore, because Rozbicki’s arguments
    that Chiang is not entitled to the benefit of each of its
    earlier-filed priority application hinges on the written
    description challenge, we affirm the PTAB’s finding that
    Chiang is entitled to the benefit of each of its earlier-filed
    applications for Chiang claims 31–39, 46, 59–61, 63, 64,
    66–71, 83, and 84.
    2. Net Etching
    We do not find, however, that the PTAB adequately
    addressed the extent to which the Chiang Application
    discloses “an etch to deposition ratio greater than 1 in the
    bottom of the plurality of vias,” a limitation which ap-
    pears in the remaining claims at issue.
    First, the PTAB did not consider Rozbicki’s expert tes-
    timony regarding “net etching.” The only explanation the
    PTAB provided as to why it rejected the testimony of
    Rozbicki’s expert on this issue was that it did not agree
    with his definition of the term “etching.” See J.A. 15 (“Dr.
    ROZBICKI   v. CHIANG                                     17
    Ruzic’s testimony is entitled to little weight because it is
    based on an untenable interpretation of the contested
    claim language.”). As such, the PTAB simply ignored Dr.
    Ruzic’s testimony regarding what “net etching” is, and the
    existence of “etch to deposition ratio greater than 1 in the
    bottom of the plurality of vias” solely based on his “unten-
    able interpretation” of “etching.” Although the PTAB
    stated in its decision on rehearing that it did not overlook
    Rozbicki’s expert testimony, which showed that Chiang’s
    examples could not result in “an etch to deposition rates
    greater than 1,” solely based on its disagreement with his
    claim construction position, that is, in fact, what the
    PTAB did in its initial decision. J.A. 15, 39. And it did
    not cure this problem in its order on reconsideration.
    Second, in addressing the “net etching” limitation, the
    PTAB failed to adequately explain how Chiang disclosed
    this limitation. The PTAB conceded that “Chiang’s dis-
    closure does not describe an . . . etch-to-deposition (E/D)
    ratio.” J.A. 18. But it concluded that Chiang discloses the
    E/D ratio limitation, because the claim language is, in the
    PTAB’s opinion, so broad that Chiang’s general discussion
    of “etching at the via bottom while material is deposited
    elsewhere, including the field,” sufficiently describes the
    contested limitation. J.A. 18. This bare assertion alone,
    however, does not suffice as adequate support. Without
    any analysis as to how a brief discussion about “etching,”
    which can occur without an “etch to deposition ratio
    greater than 1 in the bottom of the plurality of vias,” also
    discloses this limitation, the PTAB’s conclusion is un-
    founded. Therefore, the PTAB’s explanation does not
    adequately support the finding that the Chiang Applica-
    tion meets the written description requirement for the
    limitation of an “etch to deposition ratio greater than 1 in
    the bottom of the plurality of vias.”
    Therefore, we vacate the PTAB’s decision regarding
    Chiang claims 47, 49, 51, 53, 55, 57, 76–82, 85, 87, 88, and
    90 and remand for the PTAB to provide a more detailed
    18                                        ROZBICKI   v. CHIANG
    explanation of how the Chiang Application’s written
    description supports an “etch to deposition ratio greater
    than 1 in the bottom of the plurality of via,” including a
    discussion of the expert testimony from both parties.
    CONCLUSION
    For the reasons above, and because we find that
    Rozbicki’s remaining arguments are without merit, we
    affirm the PTAB’s claim construction, and consequently,
    affirm its finding of written description support and
    priority for Chiang claims 31–39, 46, 59–61, 63, 64, 66–71,
    83, and 84 as it is supported by substantial evidence. We
    vacate and remand the PTAB’s decision for Chiang claims
    47, 49, 51, 53, 55, 57, 76–82, 85, 87, 88, and 90 for further
    proceedings consistent with this opinion.
    AFFIRMED-IN-PART, VACATED-IN-PART, AND
    REMANDED