  United States Court of Appeals
      for the Federal Circuit
               __________________________

           GREENLIANT SYSTEMS, INC.,
                Plaintiff-Appellee,
                           and
     SILICON STORAGE TECHNOLOGY, INC.,
               Plaintiff-Appellee,
                            v.
                     XICOR LLC,
                  Defendant-Appellant.
               __________________________

                       2011-1514
               __________________________

   Appeal from the United States District Court for the
Northern District of California in case no. 11-CV-0631,
Judge Edward M. Chen.
             __________________________

                Decided: August 22, 2012
              ___________________________

   JO DALE CAROTHERS, Covington & Burling LLP, of
San Diego, California, argued for all plaintiffs-appellees.
With him on the brief were ALAN H. BLANKENHEIMER,
CHRISTOPHER J. LONGMAN and LESLI RAWLES GALLAGHER.
Of counsel was IAN J. MILLER. Of counsel on the brief
were RONALD L. YIN, MICHAEL G. SCHWARTZ and ERIK R.
GREENLIANT SYSTEMS    v. XICOR                           2


FUEHRER, DLA Piper LLP, of East Palo Alto, California,
for plaintiff-appellee Greenliant Systems, Inc.

   JEFFREY R. BRAGALONE, Shore Chan Braglone
DePumpo LLP, of Dallas, Texas, argued for defendant-
appellant. With him on the brief were MICHAEL W. SHORE
and CHRISTOPHER L. EVANS.
              __________________________

     Before LINN, PLAGER, and DYK, Circuit Judges.
DYK, Circuit Judge.
    Xicor LLC appeals a final judgment of the United
States District Court for the Northern District of Califor-
nia granting a declaratory judgment in favor of Greenli-
ant Systems, Inc. The district court entered the final
judgment pursuant to the parties’ agreement that the
summary judgment order in Silicon Storage Technology,
Inc. v. Xicor LLC (“SST”), 776 F. Supp. 2d 1072 (N.D. Cal.
2011), which held that claims 12 and 13 of reissued U.S.
Patent No. RE38,370 (“the RE’370 patent”) were invalid
under the rule against recapture, “applies equally in this
case and should be entered herein.” See Greenliant Sys-
tems, Inc. v. Xicor LLC, No. 11-CV-0631, slip op. at 3
(N.D. Cal. Jun. 22, 2011). The remaining claims were
dismissed by agreement of the parties. We affirm.
                        BACKGROUND
    Under 35 U.S.C. § 251, a patentee may, within two
years of the issuance of a patent, seek a broadening
reissue of that patent if, among other things, the patentee
originally claimed “less than he had a right to claim.” See
MBO Labs., Inc. v. Becton, Dickinson & Co., 602 F.3d
1306, 1313 (Fed. Cir. 2010). However, under the rule
against recapture, “a patentee is precluded from regaining
the subject matter that he surrendered in an effort to
3                                 GREENLIANT SYSTEMS   v. XICOR


obtain allowance of the original claims.” N. Am. Con-
tainer, Inc. v. Plastipak Packaging, Inc., 415 F.3d 1335,
1349 (Fed. Cir. 2005) (internal quotation marks omitted).
This case presents the question of whether broadening
claims 12 and 13 of the reissued RE’370 patent (the
claims at issue in this case) improperly recaptured claim
scope that Xicor 1 had previously surrendered during the
prosecution of its predecessor, U.S. Patent No. 5,977,585
(“the ’585 patent”).
                              I
    The specifications of the ’585 patent and the RE’370
patent are substantially identical and disclose improve-
ments to electronic memory devices, specifically EEPROM
circuits, in which “the presence or absence of charge on a
floating gate electrode indicates a binary one or zero.”
RE’370 patent col. 1 ll. 20-22; ’585 patent col. 1 ll. 16-18.
In an EEPROM, charge is transferred to and from the
floating gate electrode through a tunneling oxide layer
that acts as an insulator when not actively tunneling.
However, traditional tunneling oxide layers formed by
thermal oxide growth are susceptible to pin-hole defects
as well as compressive stress. The improved tunneling
oxide layer disclosed in the patents reduces defects and
stress, and thereby improves, among other things, proc-
essing yields, reliability, and the useful life of EEPROM
memory.
    Claim 1 of the ’585 patent recited:
    1. An improved tunneling region for use with an
    integrated circuit comprising:


    1    The RE’370 was originally assigned to Xicor Corp.,
the predecessor of the current owner, Xicor LLC. For
simplicity, we will refer to these entities collectively as
“Xicor.”
GREENLIANT SYSTEMS   v. XICOR                              4


       a first layer of polysilicon;
       a first electron tunneling layer of thermal ox-
       ide formed over said first layer of polysilicon;
       a second electron tunneling layer of annealed
       deposited silicon dioxide formed over said first
       tunneling layer having a thickness less than
       2000 Angstroms thick, said silicon dioxide
       layer being formed by low pressure chemical
       vapor deposition comprising the use of tetra-
       ethylorthosilicate; and
       a second layer of polysilicon formed over said
       layer of deposited silicon dioxide, such that
       when a bias voltage is applied between said
       first layer of polysilicon and said second layer
       of polysilicon, electron tunneling will occur
       from said first layer of polysilicon to said sec-
       ond layer of polysilicon through said first and
       second electron tunneling layers.
’585 patent col. 4 l. 66-col. 5 l. 17 (emphasis added).
Claim 4, the only other independent claim of the ’585
patent, recited:
   4. A semiconductor device including means for
   electron tunneling, comprising:
       a first conductive layer;
       an annealed silicon dioxide tunneling layer
       having a thickness less than 2000 Angstroms
       formed on top of said conductive layer, said
       silicon dioxide layer being formed by low pres-
       sure chemical vapor deposition comprising the
       use of tetraethylorthosilicate;
       a second conductive layer formed on top of
       said silicon dioxide layer, said first conductive
5                                 GREENLIANT SYSTEMS   v. XICOR


       layer acting as a source of tunneling electrons
       under an appropriate voltage bias condition,
       said second conductive layer serving as the re-
       ceptor of said tunneling electrons.
’585 patent col. 5 l. 25-col. 6 l. 8 (emphasis added). For
the purposes of this case, the two key limits of the dis-
puted “tunneling layer” in both claim 1 and claim 4 of the
’585 patent are that (1) the layer is “formed by low pres-
sure chemical vapor deposition,” and (2) the deposition
“compris[es] the use of tetraethylorthosilicate,” which is
also referred to as “TEOS.” Both of these claims are
product-by-process claims, i.e., the product is defined in
part by the process by which it is made.
                             II
     The ’585 patent and the RE’370 patent relate back to
U.S. Patent Application No. 07/195,766 (“the ’766 applica-
tion”), filed on May 17, 1988. Claims 1-12 of the originally
filed ’766 application covered methods for depositing an
electron tunneling layer, while claim 13 covered a device
containing such a deposited tunneling layer. On January
19, 1989, the examiner issued a restriction requirement
under 35 U.S.C. § 121 that required Xicor to separately
prosecute the method claims and the device claim. Xicor
elected to first prosecute the method claims after the
restriction requirement became final on August 3, 1989.
    During prosecution of the method claims, the exam-
iner rejected, among others, claim 7 as being obvious in
view of prior art “disclos[ing] that the tunneling oxide
layer can be . . . deposited by [low pressure chemical
vapor deposition].” J.A. 453. However, the examiner
stated that “[i]f claim 7 was amended to recite that the
tunneling oxide layer was deposited by [low pressure
chemical vapor deposition] using TEOS, the claim would
be allowable.” J.A. 454 (emphasis added). Xicor added
GREENLIANT SYSTEMS   v. XICOR                             6


the TEOS limit, and claim 7 was subsequently allowed as
part of U.S. Patent No. 5,219,774 (“the ’774 patent”),
which issued on June 15, 1993.
    On May 18, 1993, while the application for the ’774
patent was still pending, Xicor filed a divisional applica-
tion, which copied independent claim 13, the lone device
claim from the original ’766 application, and added,
among others, independent device claim 14. Claims 13
and 14 of the divisional application eventually issued as
claims 1 and 4 of the ’585 patent, and are thus critical to
the recapture rule issue presented in this case.
    On July 28, 1993, the examiner rejected claims 13 and
14, among others, as obvious. In response, Xicor amended
claim 13 to include the “said silicon dioxide layer being
formed by low pressure chemical vapor deposition com-
prising the use of [TEOS]” limit that was already included
in claim 14 as initially drafted in the divisional applica-
tion. J.A. 610.
    On March 25, 1994, the examiner again rejected
claims 13 and 14 on anticipation and obviousness
grounds. As described below, the process limitations in
product-by-process claims such as claims 13 and 14 can-
not be used to distinguish prior art unless the process
imparts structural differences to the product. The exam-
iner explained that the process limitations of the device
claims (i.e., how the tunneling layer is “formed by a low
pressure chemical vapor deposition comprising the use of
[TEOS]”) would not be given “patentable weight over . . .
the prior art of record” unless Xicor established that those
process limits imparted “structural limitations” that
distinguished the claimed device from prior art devices.
J.A. 621-23. As described in greater detail below, Xicor
argued in response that “deposited TEOS oxide” did in
fact have “significant structural benefits over prior art
7                             GREENLIANT SYSTEMS   v. XICOR


thermal oxide layers when used as tunneling layers.” J.A.
632 (first emphasis added). Unpersuaded, the examiner
maintained the rejections. However, the Board of Patent
Appeals and Interferences (“Board”) reversed the exam-
iner’s rejections, finding that the “advantages of TEOS
deposited oxides versus thermally grown oxides” were
“sufficient to establish unobvious differences between” the
claims and the prior art. J.A. 731-32 (emphasis added).
The ’585 patent issued on November 2, 1999, with claims
13 and 14 of the divisional application issuing as claims 1
and 4 of the ’585 patent.
    On November 2, 2001, Xicor filed a reissue application
for the ’585 patent. Xicor added new claims 12 and 13,
which omitted the “comprising the use of [TEOS]” limit,
but otherwise duplicated claims 1 and 4 of the ’585 pat-
ent. The reissue examiner found that claims 12 and 13
did not include and were “not broader than the surren-
dered subject matter,” and thus were “not barred by the
recapture rule.” J.A. 2287. The RE’370 patent issued
with new claims 12 and 13 on December 30, 2003.
                            III
    On February 11, 2011, Greenliant filed an action
against Xicor, seeking a declaration that it did not in-
fringe any claims of the RE’370 patent and that all claims
of the RE’370 patent are invalid. The parties agreed that
a summary judgment order in SST, 776 F. Supp. 2d at
1086, determining that claims 12 and 13 of the RE’370
were invalid under the recapture rule, “applies equally in
this case and should be entered herein.” See Greenliant,
No. 11-CV-0631, slip op. at 2-3. Based on the prosecution
history of the ’585 patent, the district court in the SST
case had reasoned that
    [a] reasonable, objective observer would conclude
    that the TEOS limitation was included in order to
GREENLIANT SYSTEMS   v. XICOR                              8


   distinguish the claimed . . . process limitations [in
   the product-by-process claims] from the prior art.
   By including the TEOS limitation, Xicor surren-
   dered alternative chemicals to TEOS, and these
   alternatives were recaptured by claims 12 and 13
   of the ’370 reissue patent.
SST, 776 F. Supp. 2d at 1086. 2
    Along with the stipulation regarding claims 12 and
13, the parties agreed that Greenliant’s “claims for de-
claratory judgment relief of noninfringement and invalid-
ity that relate to claims 1-11 of the [RE]’370 patent”
should be dismissed based on a covenant not to sue. With
no issues remaining, the district court entered a final
judgment in favor of Greenliant on June 22, 2011, holding
claims 12 and 13 invalid and dismissing the request for
declaratory relief as to claims 1-11. At that time, the
district court also granted SST’s motion to intervene in
the Greenliant case, allowing SST to participate in an
anticipated appeal to this court. On August 1, 2011, the
district court granted Xicor’s motion to clarify the record.
The district court clarified that its judgment was “based
on the legal and factual findings contained in the . . .
March 21, 2011 [SST order],” and ordered that “the
materials on which the [SST order] [wa]s based,” includ-
ing the prosecution history of the ’585 patent, “be made
part of this record.”
   Xicor timely appealed. We have jurisdiction under 28
U.S.C. § 1295(a)(1). 3
   2    The district court in SST also found that the
prosecution history of the process claims of the ’774
patent established an independent basis for holding that
Xicor had surrendered non-TEOS reactants prior to
recapturing those alternatives by claims 12 and 13 of the
RE’370 patent. See 776 F. Supp. 2d at 1085-86. In light
of our disposition, we need not reach this issue.
9                                GREENLIANT SYSTEMS   v. XICOR


                       DISCUSSION
    “We review a district court’s legal determination that
a reissue patent violates the rule against recapture with-
out deference.” MBO Labs., 602 F.3d at 1312. Because
the district court decided this case on summary judgment,
we apply a de novo standard of review. Edwards
Lifesciences LLC v. Cook Inc., 582 F.3d 1322, 1335 (Fed.
Cir. 2009). Regardless of the standard applied by the
district court, we apply the correct clear and convincing
evidence standard on appeal and agree with the district
court’s result. See Yoon Ja Kim v. ConAgra Foods, Inc.,
465 F.3d 1312, 1322 (Fed. Cir. 2006).
                             I
    As noted above, the reissue statute provides that “a
patentee may surrender a patent and seek reissue ‘enlarg-
ing the scope of the [original patent’s] claims’ if ‘through
error without any deceptive intent’ he claimed ‘less than
he had a right to claim in the [original] patent’ and he
applies for reissue ‘within two years from the grant of the
original patent.’” MBO Labs., 602 F.3d at 1313 (quoting
35 U.S.C. § 251). Under the rule against recapture, a
patentee’s reissue claims are invalid when those claims
were broadened to include subject matter that the pat-
entee previously surrendered during prosecution of the
original patent. Id. Thus, “a patentee is precluded ‘from
regaining the subject matter that he surrendered in an
    3   Appellees argue that we should dismiss this case
because, in their view, Xicor’s only basis for appeal is the
summary judgment order in the SST case, and there has
been no final judgment in that case. However, this is not
a situation in which the parties stipulated that the final
result of another action be the final result here. Rather,
the parties merely agreed that a specific order in the SST
case be applied and entered in this case. Appellees’
arguments are without merit.
GREENLIANT SYSTEMS   v. XICOR                            10


effort to obtain allowance of the original claims.’” N. Am.
Container, 415 F.3d at 1349 (quoting Pannu v. Storz
Instruments, Inc., 258 F.3d 1366, 1370-71 (Fed. Cir.
2001)).
    An assessment of a challenge under the recapture
rule is guided by three steps:
   (1) first, we determine whether, and in what re-
   spect, the reissue claims are broader in scope than
   the original patent claims; (2) next, we determine
   whether the broader aspects of the reissue claims
   relate to subject matter surrendered in the origi-
   nal prosecution; and (3) finally, we determine
   whether the reissue claims were materially nar-
   rowed in other respects, so that the claims may
   not have been enlarged, and hence avoid the re-
   capture rule.
N. Am. Container, 415 F.3d at 1349. Here, aside from the
removal of the TEOS limit, claims 12 and 13 of the
RE’370 patent are identical to claims 1 and 4 of the ’585
patent. The parties agree that claims 12 and 13 of the
RE’370 patent are broader than claims 1 and 4 of the ’585
patent as a result of the removal of the TEOS limit. The
parties also agree that the second step is the only step at
issue, namely, whether there was a surrender of subject
matter.
    To decide whether a patentee surrendered certain
subject matter, we must determine “whether an objective
observer viewing the prosecution history would conclude
that the purpose of the patentee’s amendment or argu-
ment” concerning a particular claim was for reasons of
patentability, that is, “to overcome prior art and secure
the patent.” Kim v. ConAgra Foods, Inc., 465 F.3d 1312,
1323 (Fed. Cir. 2006). In order to surrender subject
matter through argument as opposed to claim amend-
11                             GREENLIANT SYSTEMS   v. XICOR


ment, a patentee “must clearly and unmistakably argue
that his invention does not cover [that] subject matter to
overcome an examiner’s rejection based on prior art.”
MBO Labs., 602 F.3d at 1314.
    The parties dispute whether the prosecution history of
the method claims in the ’774 patent is relevant to
whether Xicor, in the course of the prosecution of the
device claims, surrendered devices produced through the
use of non-TEOS reactants. We do not need to reach this
question because we find that Xicor surrendered the
relevant subject matter based on the prosecution history
of the ’585 patent alone.
      As noted earlier, claims 1 and 4 of the ’585 patent
were written in product-by-process form whereby the
disputed tunneling layer element in each claim was
“defined at least in part in terms of the method or process
by which it [was] made.” Bonito Boats, Inc. v. Thunder
Craft Boats, Inc., 489 U.S. 141, 158 n.* (1989) (quoting
Donald S. Chisum, Chisum on Patents § 8.05 (1988)).
“Product-by-process claims . . . enable an applicant to
claim an otherwise patentable product that resists defini-
tion by other than the process by which it is made.” In re
Thorpe, 777 F.2d 695, 697 (Fed. Cir. 1985). “In determin-
ing validity of a product-by-process claim, the focus is on
the product and not the process of making it.” Amgen Inc.
v. F. Hoffman-La Roche Ltd., 580 F.3d 1340, 1369 (Fed.
Cir. 2009). “That is because of the . . . long-standing rule
that an old product is not patentable even if it is made by
a new process.” Id. at 1370; see also SmithKline Beecham
Corp. v. Apotex Corp., 439 F.3d 1312, 1317 (Fed. Cir.
2006) (“It has long been established that one cannot avoid
anticipation by an earlier product disclosure by claiming
. . . the product as produced by a particular process.”);
Thorpe, 777 F.2d at 697 (“If the product in a product-by-
process claim is the same as or obvious from a product of
GREENLIANT SYSTEMS   v. XICOR                            12


the prior art, the claim is unpatentable even though the
prior product was made by a different process.”). How-
ever, there is an exception to this general rule that the
process by which the product is made is irrelevant. As we
recognized in Amgen, if the process by which a product is
made imparts “structural and functional differences”
distinguishing the claimed product from the prior art,
then those differences “are relevant as evidence of no
anticipation” although they “are not explicitly part of the
claim.” 580 F.3d at 1370; see also SmithKline, 439 F.3d at
1319 (“If those product-by-process claims produced a
different product than that disclosed by the [prior art],
there would be an argument that the [prior art] did not
anticipate.”); In re Garnero, 412 F.2d 276, 279 (CCPA
1969) (finding that certain process limits are “capable of
construction as structural . . . limitations”).
    Consistent with our precedent, the Patent Office in
determining patentability considers the process in which
a product is formed if that process imparts distinctive
structural characteristics:
   The structure implied by the process steps should
   be considered when assessing the patentability of
   product-by-process claims over the prior art, espe-
   cially where the product can only be defined by
   the process steps by which the product is made, or
   where the manufacturing process steps would be
   expected to impart distinctive structural charac-
   teristics to the final product.
Manual of Patent Examining Procedure § 2113 (8th ed.
Rev. 8 July 2010) (emphasis added).
    Xicor points out that it “could only have surrendered
non-TEOS reactants by making arguments or amend-
ments whose purpose ‘was to overcome prior art and
secure the patent.’” Appellant’s Br. 28 (quoting MBO
13                             GREENLIANT SYSTEMS    v. XICOR


Labs., 602 F.3d at 1314). Xicor also points out that “the
TEOS process limitation must have imparted novel physi-
cal characteristics to the device in order for it to distin-
guish prior art.” Appellant’s Br. 29. However, Xicor
argues, “[the TEOS] process limitation did not [actually]
impart any distinctive structural characteristics to the
claimed device.” Appellant’s Br. 30. Instead, Xicor as-
serts, it was the deposition conditions such as tempera-
ture and pressure, rather than the choice of chemical
reactants, that determined the physical characteristics of
the claimed device’s tunneling layer. Thus, according to
Xicor, it did not surrender devices produced through the
use of non-TEOS reactants. We disagree.
    During the prosecution of the ’585 patent, Xicor both
amended claim 13 to add the TEOS limit and relied on
the TEOS limit appearing in claims 13 and 14 to over-
come prior art. Xicor submitted a fact declaration and
repeatedly used that declaration to argue before the
examiner, and more importantly before the Board, that
forming the claimed tunneling layer by a low pressure
chemical vapor deposition with TEOS imparted structural
differences that distinguished the claimed tunneling layer
from the prior art.
    In a March 25, 1994, office action, the examiner re-
jected claims 13 and 14 of the divisional application on
multiple grounds. The examiner first rejected claims 13
and 14 as anticipated by Hazani. The examiner noted
that “Hazani shows a[] [memory] device having first and
second polycrystalline silicon layers” and a “650 Angstrom
oxide layer” through which “[o]ne can define a plane . . . to
define a ‘tunnelling layer’ and ‘thermal layer.’” J.A. 621.
The examiner also rejected claims 13 and 14 as obvious
over Sato in view of Korma. The examiner found that
Sato described a “tunnelling silicon dioxide layer [] dis-
posed between two polycrystalline silicon layers,” and
GREENLIANT SYSTEMS   v. XICOR                            14


Korma disclosed an oxide thickness of 1000 Angstroms,
making it obvious to use an oxide thickness under 2000
Angstroms as recited in claims 13 and 14. J.A. 622.
    In conjunction with both of these rejections, the exam-
iner explained that the process limitations in the product-
by-process claims, i.e., the tunneling layer being “formed
by a low pressure chemical vapor deposition comprising
the use of [TEOS],” were “not given patentable weight
over . . . the prior art.” J.A. 621.
   [T]he applicant is reminded that it is the pat-
   entability of the final product per se which must
   be determined in a “product by process” claim, and
   not the patentability of the process, and that, as
   here, an old or obvious product produced by a new
   method is not patentable as a product, whether
   claimed in “product by process” claims or not.
   [See Thorpe, 777 F.2d 695]. The claims do not
   contain any structural limitations between the
   two oxide layers to make them distinguishable
   from one another, i.e., different molecular density
   concentrations or molecular ordering. Therefore,
   although grown by different processes, the silicon
   dioxide layers claimed are not distinguishable
   from Sato’s.
J.A. 622. The examiner also explained:
   The applicant must show the structural limita-
   tions caused from the process of making the de-
   vice. The matter given weight in claims drawn to
   structure having “process of making” segments
   are those present in the final product, and here,
   after forming one oxide layer on another, one can-
   not distinguish separate tunnelling and thermal
   oxide layers in the final product.
15                              GREENLIANT SYSTEMS   v. XICOR


J.A. 623-24.
    On August 29, 1994, Xicor’s response to the exam-
iner’s rejection was received by the Patent Office. Xicor
made no further amendments to claim 13 or 14, which, by
this time, both included the TEOS limit. However, Xicor
argued that its claimed invention, including a “deposited
TEOS oxide layer,” was “structurally distinct from the
prior art thermal oxide layers taught by Hazani and
Sato.” J.A. 628.
    Xicor pointed to “characteristics of the claimed device
[that] are clearly different and superior to the prior art
thermal oxide layers,” and thus, in Xicor’s view, evidenced
structural differences between the prior art and the
claimed TEOS deposited tunneling oxide layer. J.A. 631.
With respect to improved dielectric properties, Xicor
argued:
     [The inventor] found that low temperature depos-
     ited dielectrics, properly annealed, are better than
     thermal oxides for tunneling. For example, . . .
     the inventor discovered that TEOS tunneling ox-
     ides formed in the manner claimed in this case in-
     crease the total charge which can be conducted
     through a dielectric layer by at least an order of
     magnitude while at the same time providing a
     dramatic improvement in processing yields.
J.A. 629. Further, with respect to stress, Xicor argued:
     It is well known that thermally grown oxide lay-
     ers create heavy compressive stress. It is well
     known that TEOS deposited layer can be defined
     to induce either compressive or tensile stress, and
     be of a much lower magnitude than for thermally
     grown oxide. Consequently, stress can be mini-
     mized when using a TEOS deposited tunneling ox-
GREENLIANT SYSTEMS   v. XICOR                              16


   ide layer. This provides the advantage of a device
   having a much greater useful life.
J.A. 630 (internal quotation marks omitted).       Finally,
with respect to pinhole defects, Xicor argued:
   [P]inholes are often created in a thermal oxide
   layer as a result of small metallic impurities in
   the underlying silicon or polysilicon layer. The
   TEOS deposited layer coats all surfaces and thus
   will fill in such pinholes . . . .
J.A. 630 (internal quotation marks omitted). Due to these
improved characteristics, Xicor asserted, “the industry
has acknowledged that the use of deposited TEOS oxide
has significant structural benefits over prior art thermal
oxide layers when used as tunneling layers.” J.A. 632.
    On November 15, 1994, the examiner again rejected
claims 13 and 14, among others, as being anticipated by
Hazani, and in the alternative, as obvious over Sato in
view of Korma. Xicor subsequently appealed to the
Board. Before the Board, Xicor urged that the “prior art
devices . . . d[id] not possess the characteristics and
structure of Appellant’s claimed device,” J.A. 656, and
repeated the arguments that it had made to the examiner
regarding the improved dielectric properties, reduced
stress, and reduced defect densities of the claimed TEOS
deposited tunneling oxide layer. J.A. 657-61. With re-
spect to the anticipation and obvious rejections, Xicor
argued:
   The structure of the tunneling oxide layer accord-
   ing to the present invention is significantly differ-
   ent from prior art tunneling oxide layers since the
   inventive layer substantially reduces stress and
   defect density. Forming TEOS tunneling oxides in
   the manner claimed by [Xicor] increases the total
17                              GREENLIANT SYSTEMS    v. XICOR


     charge which can be conducted through a dielec-
     tric layer by at least an order of magnitude while
     at the same time providing a dramatic improve-
     ment in processing yields. The Examiner has not
     shown that the cited references, alone or in com-
     bination, suggest or teach this process or its ad-
     vantages.
J.A. 661 (emphasis added). Moreover, in order to distin-
guish a prior art reference that found another type of
deposition preferable to TEOS deposition for forming an
insulation layer, Xicor specifically argued that “one
skilled in the art would not have been motivated to use
TEOS for oxide deposition.” J.A. 663.
    On June 3, 1999, the Board reversed the examiner’s
rejections of claims 13 and 14, among others. The Board
understood Xicor’s arguments to be directed to the TEOS
limit, noting that “[t]he only issue on appeal is the weight
to be given to the process step of ‘said silicon dioxide layer
being formed by low pressure chemical vapor deposition
comprising the use of [TEOS].’” J.A. 726-27. The Board
held:
     The foregoing advantages of TEOS deposited ox-
     ides versus thermally grown oxides . . . are suffi-
     cient to establish unobvious differences between
     the claimed product and the prior art.
J.A. 731-32 (emphasis added).
    Xicor’s arguments clearly and unmistakably repre-
sented to the examiner and the Board that TEOS was a
necessary component of the deposition process that im-
parted the distinct structural characteristics upon Xicor’s
claimed tunneling oxide layer. There is no merit to Xi-
cor’s argument that these multiple references to the use of
TEOS can be dismissed as mere “nomenclature . . . used
GREENLIANT SYSTEMS   v. XICOR                            18


by Xicor as a label to distinguish” between different
tunneling layers. Appellant’s Br. 60. It is clear that “an
objective observer viewing the prosecution history would
conclude” that Xicor had surrendered devices produced
through the use of non-TEOS reactants during the prose-
cution of the ’585 patent to overcome prior art and secure
the patent. Kim, 465 F.3d at 1323. Under the rule
against recapture, Xicor cannot now reclaim that surren-
dered subject matter. Pannu, 258 F.3d at 1370-71.
    Xicor argues that, as a technical matter, “it is the
deposition conditions—such as temperature and pres-
sure—that determine the physical characteristics” of the
claimed tunneling oxide layer, not the reactant, such as
TEOS, that is used. Appellant’s Br. 54. Thus, according
to Xicor, the TEOS limit could not have influenced the
Board’s decision to allow the claims. But Xicor is bound
by the arguments that it made before the examiner and
before the Board. It does not matter whether the exam-
iner or the Board adopted a certain argument for allow-
ance; the sole question is whether the argument was
made. See, e.g., Springs Window Fashions LP v. Novo
Indus., L.P., 323 F.3d 989, 995 (Fed. Cir. 2003) (holding
that though “it is not clear from the record why the exam-
iner allowed the claims,” the examiner’s reasons for
allowance “do not negate the effect of the applicant’s
disclaimer”). Nor does it matter here whether TEOS
actually imparted the cited structural differences because
Xicor argued that it did.
    This principle is well established by our cases on
prosecution history disclaimer, a doctrine that “serves the
same policy” as the recapture rule, i.e., “prevent[ing] a
patentee from encroaching back into territory that had
previously been committed to the public.” MBO Labs.,
602 F.3d at 1318 (internal quotation marks omitted); see
also Hester Indus., Inc. v. Stein, Inc., 142 F.3d 1472, 1482
19                             GREENLIANT SYSTEMS    v. XICOR


(Fed. Cir. 1998). In North American Container, for exam-
ple, the patentee distinguished the “generally convex”
inner walls of his invention from prior art that, as the
patentee characterized it, contained “wall portions 3
[that] are slightly concave.” 415 F.3d at 1343 (emphasis
added). Thus, we held that “generally convex” not only
required that the majority of points along the claimed
walls were convex, but also that no portions along the
claimed walls were concave. Id. at 1345-46. The patentee
argued that, during prosecution, he “intended only to
distinguish his invention from the prior art on the basis
that the inner walls in the prior art bottles [we]re entirely
concave.” Id. But regardless of any technical merit
behind the newly explained distinction, we held that the
patentee was bound by arguments actually made during
prosecution. Id. at 1346. “Although the inner walls
disclosed in the [prior art] patents may be viewed as
entirely concave, that is not what the applicant argued
during prosecution to gain allowance for his claims.” Id.
     Here, Xicor is bound by the arguments it made during
the prosecution of the ’585 patent, which clearly establish
that it surrendered devices produced through the use of
non-TEOS reactants for the recited low pressure chemical
vapor deposition in order to gain allowance. Thus, we
affirm the district court’s holding that claims 12 and 13 of
the RE’370 patent are invalid under the rule against
recapture.
                       AFFIRMED
                           COSTS
     No costs.
