Inter Partes Review
`United States Patent No. 6,538,324
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`UNITED STATES PATENT AND TRADEMARK OFFICE
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
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`
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`Taiwan Semiconductor Manufacturing Company Limited
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`Petitioner
`
`v.
`
`Godo Kaisha IP Bridge 1
`
`Patent Owner
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`
`
`Inter Partes Review No. IPR2016-01249
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`
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`
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`PETITIONER’S REPLY TO PATENT OWNER’S RESPONSE FOR INTER
`PARTES REVIEW OF UNITED STATES PATENT NO. 6,538,324
`
`
`United States Patent No. 6,538,324
`
`
`
`
`
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`
`
`Taiwan Semiconductor Manufacturing Company Limited
`
`Petitioner
`
`v.
`
`Godo Kaisha IP Bridge 1
`
`Patent Owner
`
`
`
`Inter Partes Review No. IPR2016-01249
`
`
`
`
`
`
`
`PETITIONER’S REPLY TO PATENT OWNER’S RESPONSE FOR INTER
`PARTES REVIEW OF UNITED STATES PATENT NO. 6,538,324
`
`
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`Inter Partes Review
`United States Patent No. 6,538,324
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`TABLE OF CONTENTS
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`INTRODUCTION .......................................................................................... ii
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`
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`I.
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`II. ARGUMENT ................................................................................................... 2
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`A.
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`The Board Correctly Rejected Patent Owner’s Claim
`Constructions ......................................................................................... 2
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`1.
`
`“Therein” does not mean “throughout,” and nothing in the
`patent or prosecution history supports such a redefinition. ........ 3
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`2.
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`“Composed of” does not mean “consisting essentially of.” ....... 6
`
`B.
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`Patent Owner Misconstrues Zhang and Ding as Excluding
`Nitrogen in the Top Barrier Film .......................................................... 7
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`1.
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`2.
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`3.
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`4.
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`Zhang teaches a top tantalum-rich tantalum nitride film
`containing nitrogen, including at its surface. .............................. 7
`
`Patent Owner mischaracterizes the interface between the
`top and bottom films 32 and 22 in Zhang. .................................. 9
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`Patent Owner’s expert testimony is unreliable .........................12
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`Ding does not require forming a pure crystalline tantalum
`film to contact a copper film. ....................................................13
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`Patent Owner Never Rebuts the Board’s Initial Finding that Ding
`in View of Zhang Renders the Challenged Claims Unpatentable ......16
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`The Challenged Product Claims Do Not Require the Sputtering
`Process in the ’324 Patent, But Even if They Did, the Prior Art
`Teaches this Technique .......................................................................19
`
`The Epistar IPR Decision Does Not Establish a New Rule
`Requiring Experiments to Find a Challenged Claim Obvious ............22
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`C.
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`D.
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`E.
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`III. CONCLUSION ..............................................................................................23
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`i
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`Inter Partes Review
`United States Patent No. 6,538,324
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`TABLE OF AUTHORITIES
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` Page(s)
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`AFG Indus., Inc. v. Cardinal IG Co.,
`239 F.3d 1239 (Fed. Cir. 2001) ............................................................................ 6
`
`Epistar, Everlight, and Lite-On v. Trustees of Boston University,
`IPR2013-00298, Paper 18 (P.T.A.B. Nov. 12, 2013) ......................................... 22
`
`In re Etter,
`756 F.2d 852 (Fed. Cir. 1985) (en banc) ............................................................ 22
`
`Fujitsu Semiconductor et al. v. Zond, LLC.,
`IPR2014-00781, Paper 53 (P.T.A.B. Aug. 14, 2015) ......................................... 22
`
`Phillips v. AWH Corp.,
`415 F.3d 1303 (Fed. Cir. 2005) ............................................................................ 3
`
`Thorner v. Sony Comput. Entm’t Am., LLC,
`669 F.3d 1362 (Fed. Cir. 2012) ............................................................................ 3
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`ii
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`I.
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`INTRODUCTION
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`Inter Partes Review
`United States Patent No. 6,538,324
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`Patent Owner’s Response (POR) attempts to distinguish the prior art based
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`on an incorrect reading of Ding and Zhang, arguing both references teach a top
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`layer of pure tantalum (Ta) at the surface. See, e.g., POR, 21-22. According to
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`Patent Owner, neither reference has nitrogen in its top film, so no combination of
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`these references can render obvious the claimed first film “containing nitrogen
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`therein,” but this argument overlooks Zhang’s repeated disclosures of nitrogen
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`throughout the top tantalum-rich tantalum nitride film 32, including at its surface.
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`This fundamental error is fatal to the entirety of Patent Owner’s arguments. Patent
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`Owner does not otherwise contest the Board’s finding that a person of ordinary
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`skill in the art (POSITA) would have been motivated to modify the top Ta film of
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`Ding in view of Zhang to add nitrogen.
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`Further, the Board already rejected Patent Owner’s attempt to narrow the
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`claims to require nitrogen “throughout” the first film under the broadest reasonable
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`construction (Decision, 5-8), and Patent Owner has presented no new evidence to
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`justify changing that finding. Patent Owner also attempts to limit the claims to a
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`particular manufacturing process. The Board rejected this approach because the
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`challenged claims are product claims, not process claims, and regardless, the prior
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`art of record teaches the limitations Patent Owner proposes.
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`1
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`Patent Owner does not separately argue for validity of any of the challenged
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`dependent claims 2, 3, 6, and 7,1 so all claims stand or fall with independent claim
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`1. Nothing in the record should change the Board’s reasoning or conclusion that
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`each of the challenged claims 1-3, 5-7, and 9 of the ’324 patent is unpatentable
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`over Ding in view of Zhang.
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`II. ARGUMENT
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`A. The Board Correctly Rejected Patent Owner’s Claim
`Constructions
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`In its Decision, the Board found “the arguments and evidence presented to
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`date” did not support Patent Owner’s proposed construction that the claimed “first
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`film being composed of crystalline metal containing nitrogen therein” means “a
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`first film consisting essentially of a mixture of crystalline or polycrystalline metal
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`with nitrogen throughout.” Decision, 7. Patent Owner provides no intrinsic or
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`extrinsic evidence to change that finding.
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`Patent Owner also offers no evidence for the Board to reverse its refusal to
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`construe the “second film being composed of amorphous metal nitride” as “a
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`
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`1 Patent Owner asserts the same argument for dependent claim 9 as for independent
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`claims 1 and 5 (Zhang and Ding do not teach a “first film” containing “nitrogen
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`therein”), so that argument fails for the same reasons.
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`2
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`second film consisting essentially of a noncrystalline metal nitride throughout.”
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`Decision, 7. This construction is unsupported and further unnecessary because
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`Patent Owner does not use it to distinguish the art of record. See, e.g., Ex. 1036
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`(Harris Tr.), 78:6-20 (admitting Zhang teaches an amorphous tantalum nitride
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`bottom film); see also Ex. 1005, 3:39-41, Abstract (disclosing a “sufficiently
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`amorphous” TaNx bottom film).
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`1.
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`“Therein” does not mean “throughout,” and nothing in the
`patent or prosecution history supports such a redefinition.
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`The parties agree the Board should normally give claim terms their ordinary
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`and customary meanings. POR, 8; Ex. 1036, 144:21-145:9. “Therein” should have
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`its plain meaning because the intrinsic evidence contains no redefinition of the
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`term. Phillips v. AWH Corp., 415 F.3d 1303, 1312-13 (Fed. Cir. 2005) (en banc)
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`(holding claim terms “are generally given their ordinary and customary meaning”);
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`Thorner v. Sony Comput. Entm’t Am., LLC, 669 F.3d 1362, 1365 (Fed. Cir. 2012)
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`(“There are only two exceptions to this general rule: 1) when a patentee sets out a
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`definition and acts as his own lexicographer, or 2) when the patentee disavows the
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`full scope of a claim term either in the specification or during prosecution”).
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`“Therein” does not mean “throughout.” Ex. 1034 (dictionary definition of
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`“therein”).
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`The Board rejected Patent Owner’s attempts to import the unclaimed
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`limitation of containing nitrogen “throughout” based on manufacturing methods in
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`3
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`the ’324 patent because all the challenged claims are product claims not limited by
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`disclosed processes. Decision, 6-7. Patent Owner’s expert agrees the claims do not
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`require the processing steps from the preferred embodiments. Ex. 1036, 127:6-
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`128:1, 121:6-12.
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`The specification provides no reason to limit the claims to a disclosed
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`processing method. Patent Owner cites Fig. 21 of the ’324 patent, the result of a
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`specific RF sputtering process, as support for nitrogen “throughout” a first film
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`“i.e., from the upper surface to the bottom of the first film” (POR, 5-6), but the
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`specification’s explanation of the structure in that figure only describes grain
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`boundaries that exist “throughout” a film, “that is, from an upper surface to a
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`bottom” of the film. Ex. 1001, 2:65-3:1. As Patent Owner’s expert acknowledges,
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`the presence of physical grain boundaries “throughout” a film has nothing to do
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`with atomic nitrogen concentration “throughout” a film. Ex. 1036, 162:1-163:17.
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`The specification only uses “throughout” to describe physical structures, such as
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`recesses, holes, and grain boundaries. Ex. 1001, 2:67, 5:26, 7:49, 14:56, 20:15; see
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`also Ex. 1036, 160:13-161:8, 164:15-165:1. It never uses “throughout” to define
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`the concentration of nitrogen.
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`Patent Owner also argues a POSITA would understand the differences
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`between a crystalline metal film containing nitrogen therein, pure metal film,
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`amorphous metal nitride film, and crystalline metal nitride film. POR, 14. This
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`4
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`argument is irrelevant as the statement, even if true, would not require any specific
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`degree of nitrogen distribution within the claimed “first film,” let alone nitrogen
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`throughout the film.
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`Finally, Patent Owner cites the specification’s disclosure of a top film of a
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`diffusion barrier with -Ta and TaN0.1 “in mixture” (POR, 7, 14 (citing Ex. 1001
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`12:19-24, 12:62-67, 13:4-24, 13:57-63, 16:41-47)), but wrongly suggests this
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`disclosed “mixture” refers to a solution of tantalum and nitrogen. Instead, the
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`specification is describing a heterogeneous mixture of two different material
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`phases containing localized regions with different properties, one containing
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`nitrogen (TaN0.1) and the other containing only tantalum (-Ta). Ex. 2010 at 193
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`(describing heterogeneous mixtures); Ex. 1036, 182:7-183:14, 194:20-195:6.
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`Patent Owner cites a single statement about a “solid solution” (POR, 14 (Ex. 1001,
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`8:24-28)), but a solid solution is a homogeneous mixture in a single solid phase. Ex.
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`2036 at 3 (definition of solid solution); Ex. 1036, 188:13-17; Ex. 1038 (Banerjee
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`Dec.), ¶¶ 31-34. The solid solution in the specification refers to the TaN0.1 phase
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`alone. Id., ¶¶ 37-38. In contrast, the specification refers to the entire top film as a
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`“mixture” and not a “solid solution” because the film contains multiple phases
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`(Ta and TaN0.1). See Ex. 1002 at 220. Because one of the phases in the top film
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`contains only tantalum, the specification does not require nitrogen throughout the
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`top film.
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`5
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`Thus, the ’324 patent does not require nitrogen “throughout” the first film
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`which is a heterogeneous mixture with localized -Ta regions containing only
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`tantalum. Ex. 1036, 192:5-10 (conceding the specification does not disclose
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`whether -Ta in the disclosed embodiment contains any nitrogen). Nothing Patent
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`Owner offers requires nitrogen “throughout” the top film.
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`2.
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`“Composed of” does not mean “consisting essentially of.”
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`The Patent Owner gives no authority for construing “composed of” as
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`“consisting essentially of.” POR, 12. The case it cites, AFG Indus., Inc. v. Cardinal
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`IG Co., 239 F.3d 1239, 1245 (Fed. Cir. 2001), contrasts “composed of” with
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`“consisting of,” and explains the transitional phrase “composed of” “must be
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`interpreted in light of the specification to determine whether open or closed claim
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`language is intended.”
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`The specification of the ’324 patent supports a broad interpretation of
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`“composed of” by allowing the “first film” to include regions of tantalum metal
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`(-Ta) that are not “consisting essentially of crystalline metal containing nitrogen
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`therein.” Ex. 1001, 13:20-23 (disclosing “the crystalline metal film 16 is composed
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`of crystalline -Ta and crystalline TaN0.1 in mixture”).
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`6
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`B.
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`Patent Owner Misconstrues Zhang and Ding as Excluding
`Nitrogen in the Top Barrier Film
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`1.
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`Zhang teaches a top tantalum-rich tantalum nitride film
`containing nitrogen, including at its surface.
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`Patent Owner argues Zhang and Ding both fail to teach any nitrogen in their
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`top films or throughout those films as its construction requires2 (see, e.g., POR, 31,
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`38, 40, 44, and 46), and mistakenly asserts Zhang discloses an upper tantalum film
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`32 with no nitrogen content at its upper surface or in its entirety (see id. 21, 30, 31).
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`On the contrary, the top film 32 in Zhang is a tantalum-rich tantalum “nitride” film
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`32 (see, e.g., Ex. 1004, 3:14-16), which means it is a film containing nitrogen.
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`Patent Owner’s attempt to characterize this film as a pure tantalum film and
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`disregard the word “nitride” is disingenuous. Ex. 1036, 62:17-63:5; see also Ex.
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`1004, Abstract (disclosing, “The nitrogen percentage for the second portion (32) is
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`lower than the nitrogen atomic percentage for the first portion (22)”).
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`Zhang consistently describes the top nitride film 32 as containing nitrogen at
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`its upper surface in contact with a copper layer. For example, Zhang discloses, “By
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`keeping the nitrogen concentration at the surface that contacts copper relatively
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`low, better adhesion can be achieved.” Id. 5:57-59. “Low” does not mean only
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`2 Patent Owner’s expert provides no opinions where nitrogen is not required
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`“throughout” the claimed first film. Ex. 1036, 151:3-152:2.
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`7
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`“zero.” Zhang also discloses, “At the upper surface, the atomic percent tantalum
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`may be at least 95% and the atomic percent nitrogen may be less than 5% if copper
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`adhesion is particularly problematic.” Id. 3:59-62; see also Ex. 1036, 33:13-22
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`(testifying Zhang at col. 3, lines 59-62 refers to the upper surface of top film 32).
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`Zhang also includes claim 7 that teaches forming the top film 32 using a constant
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`flow of nitrogen, i.e., to incorporate nitrogen throughout the film, unlike its
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`dependent claim 9 where the nitrogen gas is “reduced to zero” when forming film
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`32. Ex. 1004, 6:47-54, 6:58-60; Ex. 1036, 176:11-177:21.
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`Zhang never discloses the upper surface of the top film 32 contains no
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`nitrogen and, contrary to Patent Owner’s assertion (see, e.g., POR, 21-22, 27-31,
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`33-45), nowhere teaches a desire to form a top film of pure tantalum. Instead,
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`Zhang’s Fig. 4 illustrates the top film is not pure tantalum, as the tantalum atomic
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`percent never reaches 100% at the upper surface (i.e., at a distance of zero). See Ex.
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`1032; Ex. 1004, Fig. 4. Zhang discloses a top tantalum-rich tantalum nitride film
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`32, meaning one containing nitrogen, with the upper surface of the film containing
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`a lower nitrogen content than the other portions of film. Ex. 1004, Abstract,
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`3:57-62. This does not mean the surface can have no nitrogen.
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`Patent Owner’s expert admits the upper surface of Zhang’s top film 32
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`contains some nitrogen. See Ex. 1036, 40:1-6 (“Zhang discloses that there may be
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`a 5 percent nitrogen only at -- as an upper boundary”); see also, 42:2-9 (“the
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`8
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`person skilled in the art would understand that that means extremely low,
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`approaching zero”), 42:15-21 (“I can't say that with a high degree of certainty,
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`absolutely no nitrogen . . .”), 54:14-20.
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`2.
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`Patent Owner mischaracterizes the interface between the
`top and bottom films 32 and 22 in Zhang.
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`Having no evidence to support its arguments, Patent Owner asserts a
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`POSITA, “[u]sing characterization techniques known at the time,” would not have
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`viewed the middle dotted line, in Patent Owner’s annotated Fig. 4 of Zhang
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`(reproduced below), as the location of an interface between distinct films. Patent
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`Owner instead argues the dotted line in Fig. 4 is merely a “time stamp” indicating
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`the termination of nitrogen flow. POR, 33. Patent Owner further asserts a POSITA
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`would have recognized the interface between the top and bottom films “lies at the
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`point where the nitrogen concentration reaches zero . . . where the layer of pure
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`tantalum (shown in red) meets the layer of amorphous tantalum nitride (shown in
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`blue).” POR, 39.
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`These arguments conflict with the specification. Zhang discloses forming the
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`top film (32) when “the nitrogen-containing gas is terminated.” Ex. 1004, 3:37-47
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`(“In forming film 32, the nitrogen-containing gas is terminated . . . .”). Thus,
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`Zhang discloses that the dotted line in Fig. 4, when nitrogen gas is turned off, is the
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`start of “forming film 32,” which contradicts Patent Owner’s unsupported
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`characterization about the dotted line.
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`Zhang also suggests the thickness of the top and bottom films 32 and 22
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`would be the same if the times needed to form the films are the same. Id. 4:1-7.
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`Contrary to Patent Owner’s assertion, film 32 begins to form when nitrogen
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`content starts to decrease, corresponding to the middle dotted line at distance of
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`175 angstroms on the x-axis of the figure.
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`Patent Owner’s assertions contradict its other arguments. Patent Owner
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`asserts that if “some residual nitrogen may be present in the system during
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`deposition of” the top film, a POSITA “would have recognized that insufficient
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`nitrogen would be present to make any changes to the material properties of the
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`tantalum.” POR, 51. But, in referring to the annotated Zhang Fig. 4, Patent Owner
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`asserts that residual nitrogen (i.e., nitrogen content shown at a distance between
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`approximately 100 and 175 angstroms in the blue layer) would change the film’s
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`material properties to turn a portion of the top film into amorphous tantalum nitride.
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`Patent Owner also argues a POSITA would not have viewed the dotted line
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`in Zhang’s Fig. 4 as the interface of two films “because the material characteristics
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`of the film(s) at a point immediately on either side of that dotted line would be
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`substantially identical, i.e., within the determination abilities of characterization
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`techniques . . . .” POR, 38. But the same reasoning applies equally at the interface
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`between the red and blue layers proposed by Patent Owner, since the material
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`characteristics “immediately” to the left or right of the interface would be the same.
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`Patent Owner finally argues a POSITA would have recognized the actual
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`interface in Zhang lies where the nitrogen concentration goes to zero. POR, 39. But
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`it is not clear from Zhang Fig. 4 whether the nitrogen percentage of the top film
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`goes to zero (see Section II(B)(1) above), and Patent Owner’s position means no
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`interface between top and bottom films 32 and 22 exists if any nitrogen is at the
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`surface. In any event, no matter how Patent Owner mischaracterizes Fig. 4, it does
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`not change the fact that Zhang’s written disclosure teaches nitrogen at the upper
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`surface of film 32.
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`3.
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`Patent Owner’s expert testimony is unreliable
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`Patent Owner’s mischaracterization of Zhang required its expert to take
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`unreasonable positions including:
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`(1) testifying the tantalum-rich tantalum “nitride” film 32 in Zhang contains
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`no nitrogen (Ex. 1036, 62:17-19);
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`(2) characterizing Zhang’s description of “less than 5 percent nitrogen” at
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`the upper surface of film 32 in col. 3, lines 59-61 as a “mistake” (id. 41:3-7);
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`(3) interpreting Zhang’s disclosure of “approximately zero” percent nitrogen
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`in col. 3, lines 53-54 as “always equal to zero” (id., 46:5-8);
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`(4) asserting Zhang’s disclosure of “essentially no nitrogen atoms” in col. 3,
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`lines 54-57 means “zero” nitrogen (id., 58:21-59:10);
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`(5) arguing first that Zhang’s disclosure in col. 5, lines 57-59 of “relatively
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`low” nitrogen concentration at the upper surface of film 32 contacting copper
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`cannot contain 4% nitrogen because that value would be undetectable, but then
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`conceding 4% nitrogen at the surface may be detectable (id. 41:18-45:7); and
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`(6) characterizing Zhang’s Fig. 4 as an inaccurate “cartoon,” despite relying
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`on this figure to allege the location of an interface between Zhang’s top and bottom
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`films (id., 89:21-90:15). Petitioner invites the Board to reject the opinions of Patent
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`Owner’s expert as his opinions conflict with Zhang’s disclosure so many times.
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`4.
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`Ding does not require forming a pure crystalline tantalum
`film to contact a copper film.
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`Although Patent Owner asserts Ding requires a “pure” Ta film to provide
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`easy wetting by the layer of copper (POR, 28), Patent Owner’s expert concedes the
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`crystallinity of Ding’s top tantalum film, rather than its purity, is what improves
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`formation of the copper layer. See Ex. 1036, 82:22-83:7 (“A. Yes. So Ding does, of
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`course, describe [as quoted in para. 112 of Ex. 2011] that the tantalum surface
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`should be a <002> crystalline orientation in order to improve the adhesion and
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`formation of the <111> copper”).
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`Patent Owner cites Ding at 8:1-4 and FIG. 2 (POR, 24-26, 32, 52, 53), but
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`these portions of the reference merely require the crystalline Ta layer be
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`“sufficiently thick” for enabling easy wetting of the Ta surface by copper. See Ex.
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`1005, 7:66-8:4 (“The [tantalum] layer must be sufficiently thick to provide a
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`tantalum <002> crystalline orientation which enables easy wetting of the tantalum
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`surface by the copper and depositing of a copper layer having a high <111> crystal
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`orientation”). Even Patent Owner’s expert agrees this portion in Ding refers to
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`thickness, and does not state a requirement for a pure Ta layer. Ex. 1036, 220:15-
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`221:15 (testifying “[t]hat particular sentence [Ding, 8:1-4] is talking about the
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`requirement of the thickness”).
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`Ding never addresses purity levels its top Ta film, and Patent Owner never
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`explains how FIG. 2 of Ding relates to purity of the tantalum film rather than the
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`need for a minimum thickness. See Ex. 1005, 4:59-62. Patent Owner’s citation to
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`Ding’s Abstract and 3:27-3 (POR, 24, 32) also do not discuss the purity level of the
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`tantalum top layer. Ding only requires its tantalum film to have a certain thickness
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`14
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`for enabling easy wetting by the copper layer with a high crystal orientation. Id.,
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`2:52-55, 3:12-18, 8:1-4, 8:18-22, Fig. 2; Ex. 1036, 220:15-221:15.
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`Ding does not teach the desirability of a pure Ta film, as Patent Owner
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`suggests, but just uses “pure” to distinguish a single-layer barrier (tantalum layer)
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`from a multi-layer barrier including metal nitride (tantalum nitride layer and a
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`tantalum layer). See Ex. 1005, 9:47-49 (disclosing “a layer of pure Ta does not
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`provide a diffusion barrier which performs as well as the TaNx/Ta barrier layer
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`structure”), 4:6-11 (disclosing 70% crystallographic copper is obtained in Ding’s
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`two-layer structure compared to a “pure” Ta barrier layer), 10:1-3 (contrasting
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`TaN/Ta barrier with a “pure” Ta layer). Patent Owner’s expert agrees. Ex. 1036,
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`97:6-98:16.
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`This is consistent with Ding’s prosecution history, which explains Ding’s
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`claimed barrier requires only one tantalum layer (i.e., a pure tantalum layer), unlike
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`the prior art (Hindman), which further discloses an optional titanium layer for its
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`barrier structure. Ex. 2002, 18-19 (“The Hindman et al. disclosure further contrasts
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`with applicants’ teachings which clearly require the use of a pure tantalum layer
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`directly underlying a deposited copper layer. Hindman et al. states the use of a
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`titanium layer directly underlying the aluminum layer is optional . . . .”).
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`Consistent with its specification, Ding’s prosecution history also contains
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`statements requiring the top tantalum layer to have a certain thickness to enable
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`15
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`Inter Partes Review
`United States Patent No. 6,538,324
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`easy wetting of its surface by copper. Id., 19 (“[Ding’s] [c]laims 8-17, which are
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`rejected in view of Hindman et al. require a tantalum layer having a thickness
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`falling within a particular range.”); id. (“[Hindman has] no requirement that such a
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`titanium layer have any particular thickness”). The prosecution history never
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`requires Ding’s tantalum film to be “pure” Ta in terms of atomic percentage.
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`Ding does not require an atomically pure tantalum film to contact a copper
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`layer. See Ex. 1033, 1:47-57 (referring to Ding’s patent application and teaching
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`that Ding’s top film may contain a “small amount of nitrogen (typically less than
`
`about 15 atomic percent)” at its surface).
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`C.
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`Patent Owner Never Rebuts the Board’s Initial Finding that Ding
`in View of Zhang Renders the Challenged Claims Unpatentable
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`The Board found Ding meets every claim element of the challenged ’324
`
`patent claims, except for the requirement the top tantalum film of the barrier must
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`contain nitrogen. Decision, 10-13. The Board agreed it would have been obvious to
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`modify the top film in Ding to add nitrogen in an amount less than the bottom
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`tantalum nitride film in view of Zhang’s two-layer diffusion barrier comprising
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`films 22 and 32, which is directed to the same problems and solution as the ’324
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`patent and Ding. Decision, 15, 22-23. The Board explained that Zhang teaches how
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`to include nitrogen, in a lesser amount, in a second-formed layer of a two-layered
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`barrier film. Decision, 13 (citing Ex. 1004, 3:37-62, Fig. 4).
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`16
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`United States Patent No. 6,538,324
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`The Petition further explains how a POSITA at the time of the ’324 patent
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`would have found it obvious to modify the top tantalum film in Ding to add a small
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`amount of nitrogen, as in Zhang’s top tantalum-rich tantalum nitride film 32,
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`because doing so would provide well-known benefits for Ding’s diffusion barrier
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`structure, including better polishing characteristics, lower resistivity, and improved
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`blocking of copper diffusion. Ex. 1003, ¶¶ 74, 139; Decision, 13.
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`Patent Owner does not dispute a POSITA would have been motivated to add
`
`a small amount of nitrogen into the top tantalum film in Ding. Its expert agrees
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`with Petitioner that adding a small amount of nitrogen into a tantalum film would
`
`advantageously reduce the film’s resistivity. Petition, 15, 23, 29-30.
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`Q. So is it within the scope of what's taught in the ’324
`
`patent to have a film that would have no nitrogen at all?
`
`A.
`
`It's also apparent to anyone who is examining this of skill
`
`in the art that you can decrease from that number, which
`
`is favorable in terms of the value of resistivity by adding
`
`flow rate in the data points for all of the positions greater
`
`than zero. So you decrease resistivity by the addition of
`
`any amount of nitrogen, therefore, a person skilled in
`
`the art would not be motivated to not have nitrogen,
`
`based on this data [in Fig. 9 of the ’324 patent].
`
`Q. You're referring to the decrease in resistivity as
`
`nitrogen is added?
`
`A. Yes.
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`17
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`United States Patent No. 6,538,324
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`Q. Which is desirable?
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`A. You want the resistivity to go down.
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`Ex. 1036, 125:3-20 (emphasis added).
`
`Patent Owner’s expert also explains that Fig. 6 in Sun does not illustrate
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`resistivity data for nitrogen content in a tantalum film between zero and 15 percent
`
`nitrogen, e.g., corresponding to the local minimum resistivity value in Fig. 9 of
`
`the ’324 patent. See Ex. 1036, 200:15-201:5; Ex. 1001, Fig. 9. See also Ex. 2042 at
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`3 (“It first shows that the electrical resistivity of the pure Ta film is about 150 mΩ
`
`cm and is initially decreased to about 80 mΩ cm as small amount of nitrogen is
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`added to the sputtering gas”); id. Figs. 1, 3. This testimony contradicts Patent
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`Owner’s unsupported contention that introducing nitrogen into a tantalum film has
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`a “deleterious effect on resistivity.” POR, 51.
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`Patent Owner’s arguments about the benefits to polishing characteristics of
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`adding nitrogen rely on circular reasoning. Patent Owner argues that because Ding
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`teaches a top tantalum film without nitrogen, adding nitrogen to Ding’s top film
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`would violate Ding’s teaching. POR, 47-48. Likewise, Patent Owner’s expert
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`opines, “You cannot add nitrogen to tantalum to the degree that it would change its
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`CMP properties and still maintain a pure tantalum layer which is what is taught by
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`Ding.” Ex. 1036, 243:7-15. Such logic, if accepted, would defeat any combination
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`of references.
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`18
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`Inter Partes Review
`United States Patent No. 6,538,324
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`Patent Owner also applies faulty logic with respect to the benefit of adding
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`nitrogen to Ding’s top film to help block copper diffusion paths. POR, 49-50.
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`Patent Owner argues that “adding additional nitrogen could cause unknown
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`potential changes in properties that would deleteriously affect the subsequent
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`copper properties” (id., 50), but only cites its expert who supplies no supporting
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`evidence and admits to not even looking for any. Ex. 1036, 234:6-10.
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`In sum, Patent Owner has not offered any supported argument that rebuts the
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`motivations cited by Petitioner for a POSITA to modify Ding in view of Zhang.
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`D. The Challenged Product Claims Do Not Require the Sputtering
`Process in the ’324 Patent, But Even if They Did, the Prior Art
`Teaches this Technique
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`Although the Board rejected Patent Owner’s attempt to import process
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`limitations from the specification into the claims, Patent Owner tries to advance
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`this argument in a different way by arguing Zhang and Ding do not teach the same
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`sputtering process as the ’324 patent. POR, 4, 21, 43. Patent Owner argues Zhang
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`and Ding turn off nitrogen gas flow to form a top barrier film (see, e.g., id., 21, 41,
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`42), and use lower RF power than the ’324 patent’s disclosed embodiment. (see,
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`e.g., id., 21, 22, 41, 43).
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`Patent Owner’s first argument is incorrect, and the second is misleading.
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`Although Zhang discloses embodiments that turn off the nitrogen gas to form the
`
`top film 32, it also teaches using a “lower flowrate” of nitrogen gas as taught in
`
`19
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`United States Patent No. 6,538,324
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`the ’324 patent. Ex. 1004, 6:47-54, 6:58-60. Zhang’s claims 7 and 9 separately
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`claim these different embodiments. Id.; see also Ex. 1036, 176:11-177:21.
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`With regard to RF power, the ’324 patent claims do not require increasing
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`RF power as Patent Owner alleges to form the claimed “crystalline tantalum
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`containing nitrogen.” POR, 49. Neither the prior art nor the ’324 patent requires a
`
`high RF sputtering power to form a crystalline tantalum layer with nitrogen.
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`The ’324 patent does not even require RF power to form the claimed “first film.”
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`See Ex. 1001, 14:15-20 (disclosing a fourth embodiment using only DC sputtering
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`rather than RF sputtering); Ex. 1036, 116:5-117:5.
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`Even if the ’324 patent claims required RF power, Sun (Ex. 1007) and
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`Stavrev (Ex. 1015) each discloses forming a crystalline tantalum film containing
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`nitrogen using a low RF power. See Ex. 1007, Fig. 2 (disclosing that, at 0.3 kW
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`sputtering power, which is lower than the minimum RF power used in the ’324
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`patent, the tantalum film remains crystalline with nitrogen content below ~33%);
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`Ex. 1015, 8 and Fig. 2 (disclosing crystalline tantalum films containing nitrogen
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`formed using 1 kW RF power, which is lower than the minimum RF power used in
`
`the ’324 patent).
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`Patent Owner’s expert admits forming a crystalline tantalum film with
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`nitrogen does not depend solely upon RF power or nitrogen gas flow, and a
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`POSITA would have known changing various sputtering parameters can cause
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`20
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`United States Patent No. 6,538,324
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`formation of an amorphous or a crystalline film. Ex. 2011, ¶ 180; Ex. 1036,
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`105:12-21,
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