`
`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
`
`
`DECLARATION OF DR. SANJAY K. BANERJEE
`IN SUPPORT OF PETITION FOR INTER PARTES REVIEW OF UNITED
`STATES PATENT NO. 6,538,324
`
`TSMC Exhibit 1003
`
`Page 1 of 196
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`

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`TABLE OF CONTENTS
`
`INTRODUCTION ........................................................................................... 3
`
`SUMMARY OF OPINIONS ........................................................................... 3
`
`
`I.
`
`II.
`
`III. BACKGROUND AND QUALIFICATIONS ................................................. 4
`
`A.
`
`B.
`
`C.
`
`Background ........................................................................................... 4
`
`Previous Expert Witness Experience .................................................... 7
`
`Compensation ........................................................................................ 7
`
`IV. MATERIALS REVIEWED ............................................................................ 8
`
`V.
`
`LEGAL STANDARDS ................................................................................... 9
`
`A. Anticipation ......................................................................................... 10
`
`B.
`
`Obviousness ......................................................................................... 11
`
`VI. TECHNOLOGICAL BACKGROUND ........................................................ 16
`
`A. Diffusion Barrier Basics ...................................................................... 22
`
`VII. THE ’324 PATENT ........................................................................................ 25
`
`A.
`
`B.
`
`Claims of the ’324 Patent .................................................................... 25
`
`Prosecution History ............................................................................. 27
`
`VIII. LEVEL OF ORDINARY SKILL .................................................................. 31
`
`IX. CLAIM CONSTRUCTION .......................................................................... 32
`
`X. ANALYSIS .................................................................................................... 32
`
`A. Overview of the Prior Art .................................................................... 32
`
`1.
`
`Zhang......................................................................................... 34
`
`
`
`1
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`

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`2.
`
`3.
`
`Ding ........................................................................................... 36
`
`Sun ............................................................................................. 39
`
`B.
`
`I believe that the combined teachings of Zhang and Ding render
`claims 1-3, 5-7, and 9 obvious ............................................................ 40
`
`1.
`
`2.
`
`3.
`
`4.
`
`5.
`
`6.
`
`7.
`
`Claim 1 is obvious..................................................................... 40
`
`Claim 2 is obvious..................................................................... 60
`
`Claim 3 is obvious..................................................................... 64
`
`Claim 5 is obvious..................................................................... 65
`
`Claim 6 is obvious..................................................................... 67
`
`Claim 7 is obvious..................................................................... 68
`
`Claim 9 is obvious..................................................................... 68
`
`C.
`
`D.
`
`I believe that the combined teachings of Zhang, Ding, and Sun
`render claims 1-3, 5-7, and 9 obvious ................................................. 70
`
`I believe that the combined teachings of Ding in view of Zhang
`render claims 1-3, 5-7, and 9 obvious ................................................. 73
`
`4.
`
`5.
`
`6.
`
`7.
`
`8.
`
`9.
`
`Claim 1 is obvious..................................................................... 73
`
`Claim 2 is obvious..................................................................... 90
`
`Claim 3 is obvious..................................................................... 94
`
`Claim 5 is obvious..................................................................... 95
`
`Claim 6 is obvious..................................................................... 97
`
`Claim 7 is obvious..................................................................... 98
`
`10. Claim 9 is obvious..................................................................... 98
`
`Conclusion ............................................................................................................... 99
`
`
`
`2
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`I, Sanjay Kumar Banerjee, declare as follows:
`
`I.
`
`INTRODUCTION
`
`1. My name is Dr. Sanjay Kumar Banerjee. I have been asked to submit
`
`this declaration on behalf of Taiwan Semiconductor Manufacturing Company
`
`Limited (“TSMC” or “Petitioner”) for a petition for inter partes review of U.S.
`
`Patent No. 6,538,324 (“the ’324 patent”), which I understand is being submitted to
`
`the Patent Trial and Appeal Board of the United States Patent and Trademark
`
`Office by TSMC. I have been told that the ’324 patent is owned by Godo Kaisha IP
`
`Bridge 1.
`
`2.
`
`I have been retained as a technical expert by TSMC to study and
`
`provide my opinions on the technology claimed in, and the patentability or non-
`
`patentability of, claims 1-3, 5-7, and 9 in the ’324 patent (“Challenged Claims”). I
`
`have also been asked to provide my opinions regarding the level of ordinary skill
`
`in the art at the time the Japanese priority application of the U.S. application
`
`leading to the ’324 patent was filed, which I have been told was June 24, 1999.
`
`II.
`
`SUMMARY OF OPINIONS
`
`3.
`
`Based on my experience, knowledge of the art at the relevant time,
`
`analysis of prior art references, and the understanding a person of ordinary skill in
`
`the art would give to the claim terms in light of the specification, it is my opinion
`
`
`
`3
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`that all of the Challenged Claims of the ’324 patent are unpatentable as being
`
`obvious over the prior art references I discuss below.
`
`III. BACKGROUND AND QUALIFICATIONS
`A. Background
`I am currently the Cockrell Family Chair Professor of Electrical and
`4.
`
`Computer Engineering at the University of Texas at Austin. At UT Austin, I am
`
`also the director of the Microelectronics Research Center. I have been a faculty
`
`member at UT Austin since 1987.
`
`5.
`
`I have also been active in industries related to the relevant field of
`
`semiconductor processing for integrated circuits. As a Member of the Technical
`
`Staff, Corporate Research, Development and Engineering of Texas Instruments
`
`Incorporated from 1983–1987, I worked on polysilicon transistors and dynamic
`
`random access trench memory cells used by Texas Instruments in the world’s first
`
`4-Megabit DRAM, for which I was co-recipient of the Best Paper Award, IEEE
`
`International Solid State Circuits Conference, 1986.
`
`6.
`
`I received a B.Tech from the Indian Institute of Technology,
`
`Kharagpur, an M.S. and Ph.D. from the University of Illinois at Urbana-
`
`Champaign, all in Electrical Engineering.
`
`7.
`
`I am a leading researcher and educator in various areas of transistor
`
`device fabrication technology, including the fabrication, characterization and
`
`
`
`4
`
`Page 5 of 196
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`applications of memory devices, transistors, and nanotechnology. My research has
`
`been funded by the Texas Advanced Technology Program (ATP), the Texas
`
`Higher Education Coordinating Board, the National Science Foundation, the
`
`SEMATECH (Semiconductor Manufacturing Technology) consortium, the SRC
`
`(Semiconductor Research Corporation) consortium, DARPA, and the Department
`
`of Energy, among others.
`
`8.
`
`At the University of Texas, I am the director of the Microelectronics
`
`Research Center, comprised of faculty colleagues, graduate, and undergraduate
`
`students. I also serve as the director of the South West Academy of
`
`Nanoelectronics, one of three centers in the United States to develop a replacement
`
`for MOSFETs.
`
`9.
`
`I have published over 1,000 technical articles; many related to
`
`semiconductor fabrication technology, most at highly competitive refereed
`
`conferences and rigorously reviewed journals. I have also published 8 books or
`
`chapters on transistor device physics and fabrication, and have supervised over 50
`
`Ph.D. and 60 MS students.
`
`10.
`
`I have been a member of scientific organizations and committees,
`
`including the IEEE Dan Noble Award Committee from 2010–2013, serving as
`
`Chair from 2012–2013, the International Technology Roadmap for
`
`Semiconductors, the International Conference on MEMS (Microelectromechanical
`
`
`
`5
`
`Page 6 of 196
`
`

`

`Systems) and Nanotechnology, the IEEE International Conference on
`
`Communications, Computers, Devices, the International Electron Devices
`
`Meeting, the International Conference on Simulation of Semiconductor Processes
`
`and Devices, and the IEEE Symposium on VLSI (Very-Large-Scale Integration)
`
`Technology.
`
`11.
`
`I have served as the Session Chair for the “Device Technology”
`
`Session conducted at the IEEE International Electron Devices Meeting in 1989–
`
`1990. I have also served as the General Chairman for the IEEE University
`
`Government Industry Microelectronics Symposium in 1994–1995, and Chair of the
`
`IEEE Device Research Conference.
`
`12.
`
`I have served on the Technical Advisory Boards of AstroWatt, DSM
`
`Semiconductors, Cambrios, Nanocoolers Inc., BeSang Memories, Organic ID and
`
`ITU Ventures; Gerson Lehmann Group, NY; Austin Community College; Asia
`
`Pacific IIT; Rochester Institute of Technology, and HSMC Foundry.
`
`13.
`
`I received the Engineering Foundation Advisory Council Halliburton
`
`Award (1991), the Texas Atomic Energy Fellowship (1990–1997), Cullen
`
`Professorship (1997–2001) and the Hocott Research Award from UT Austin
`
`(2007). I also received the IEEE Grove Award (2014), Distinguished Alumnus
`
`Award, IIT (2005), Industrial R&D 100 Award (2004), ECS Callinan Award,
`
`
`
`6
`
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`2003, IEEE Millennium Medal, 2000, NSF Presidential Young Investigator Award
`
`in 1988, and several SRC Inventor Recognition and Best Paper Awards.
`
`14.
`
`I was a Distinguished Lecturer for IEEE Electron Devices Society,
`
`and am a Fellow of the Institute of the Electrical and Electronics Engineers (IEEE),
`
`the American Physical Society (APS) and the American Association for the
`
`Advancement of Science (AAAS).
`
`15.
`
`I am the inventor or co-inventor of over 30 United States patents in
`
`various areas of transistor device fabrication technology.
`
`16. Additional details about my employment history, fields of expertise,
`
`and publications are further included in my curriculum vitae (attached as Appendix
`
`A).
`
`B.
`17.
`
`Previous Expert Witness Experience
`
`I have served as an expert witness since the mid 1990’s. In the last ten
`
`years or so, I have testified at the ITC three times, and the Northern District of
`
`California once. In addition, I have been deposed six times on patents related to
`
`CMOS and semiconductor memories such as flash and DRAMs. Several of these
`
`have been in IPR cases.
`
`C. Compensation
`I am being compensated for services provided in this matter at my
`18.
`
`usual and customary rate of $500 per hour plus travel expenses. My compensation
`
`
`
`7
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`

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`is not conditioned on the conclusions I reach as a result of my analysis or on the
`
`outcome of this matter. Similarly, my compensation is not dependent upon and in
`
`no way affects the substance of my statements in this declaration.
`
`19.
`
`I have no financial interest in Petitioner or any of its subsidiaries. I
`
`also do not have any financial interest in Godo Kaisha IP Bridge 1. I do not have
`
`any financial interest in the ’324 patent and have not had any contact with any of
`
`the named inventors of the ’324 patent (Masayoshi Tagami and Yoshihiro
`
`Hayashi).
`
`IV. MATERIALS REVIEWED
`
`20.
`
`In forming my opinions, I have reviewed the following materials:
`
`
`
`Exhibit 1001:
`
`Exhibit 1002:
`
`Exhibit 1004:
`
`Exhibit 1005:
`
`Exhibit 1006:
`
`Exhibit 1007:
`
`Exhibit 1008:
`
`Exhibit 1009:
`
`U.S. Patent No. 6,538,324 to Tagami et al.
`
`File History of U.S. Patent No. 6,538,324 to Tagami et al.
`
`U.S. Patent No. 5,893,752 to Zhang et al.
`
`U.S. Patent No. 6,887,353 to Ding et al.
`
`Holloway et al., “Tantalum as a diffusion barrier between
`copper and silicon: Failure mechanism and effect of
`nitrogen additions,” Journal of Applied Physics, 71(11),
`5433-5444 (1992).
`
`Sun et al., “Properties of reactively sputter-deposited Ta-
`N thin films,” Thin Solid Films, 236 (1993) 347-351.
`
`U.S. Patent No. 5,858,873 to Vitkavage et al.
`
`U.S. Patent No. 5,668,411 to Hong et al.
`
`
`
`8
`
`Page 9 of 196
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`

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`Exhibit 1010:
`
`Exhibit 1015:
`
`Exhibit 1017:
`
`Exhibit 1019:
`
`Exhibit 1021:
`
`Exhibit 1023:
`
`Excerpt of El-Kareh, “Fundamentals of Semiconductor
`Processing Technologies,” Kluwer Academic Publishers
`(1995).
`
`Stavrev et al., “Crystallographic and morphological
`characterization of reactively sputtered Ta, Ta-N and Ta-
`N-O thin films,” Thin Solid Films, 307 (1997) 79-88.
`
`Duan et al., “Magnetic Property and Microstructure
`Dependence of CoCrTa/Cr Media on Substrate
`Temperature and Bias,” IEEE Transactions on Magnetics,
`Vol. 28, No. 5, September 1992.
`
`Moussavi et al., “Comparison of Barrier Materials and
`Deposition Processes for Copper Integration,”
`Proceedings of the IEEE 1998 International Interconnect
`Technology Conference, pp. 295-97 (1998).
`
`Wijekoon et al., “Development of a Production Worthy
`Copper CMP Process,” 1998 IEEE/SEMI Advanced
`Semiconductor Manufacturing Conference, pp. 354-63
`(1998).
`
`Wang et al., “Barrier Properties of Very Thin Ta and
`TaN layers Against Copper Diffusion,” J. Electrochem.
`Soc., Vol. 145, No. 7, pp. 2538-45.
`
`V. LEGAL STANDARDS
`
`21.
`
`I am not an attorney and have not been asked to offer my opinion on
`
`the law. However, as an expert offering an opinion on whether the claims in the
`
`’324 patent are patentable, I understand that I am obliged to follow existing law. I
`
`have been told the following legal principles apply to analysis of patentability
`
`
`
`9
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`pursuant to 35 U.S.C. §§ 102 and 103 as those statutes existed prior to the changes
`
`of the America Invents Act.1
`
`22.
`
`I also have been told that, in an inter partes review proceeding, patent
`
`claims may be deemed unpatentable if it is shown by preponderance of the
`
`evidence that they were anticipated and/or rendered obvious by one or more prior
`
`art patents or publications.
`
`A. Anticipation
`I have been told that for a claim to be anticipated under pre-AIA 35
`23.
`
`U.S.C. § 102, every limitation of the claimed invention must be found in a single
`
`prior art reference. I have been asked to assume each of Exhibits 1004-1010, 1015,
`
`1017, 1019, 1021, and 1023 qualifies as prior art to the Challenged Claims of the
`
`324 patent.
`
`24.
`
`I have been told that a claim is unpatentable as anticipated under pre-
`
`AIA § 102(a) if the claimed invention was “known or used by others in this
`
`country, or patented or described in a printed publication in this or another country,
`
`before the invention thereof by the applicant for patent.”
`
`
`1 I was told Congress changed U.S. patent law in the American Invents Act,
`
`Pub. L. No. 112-29, 125 Stat. 284 (2011) (“AIA”). I was also told that the ’324
`
`patent is governed by statutes as they existed prior to the enactment of the AIA.
`
`
`
`10
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`25.
`
`I understand that a claim is unpatentable as anticipated under pre-AIA
`
`§ 102(b) if the claimed invention was “patented or described in a printed
`
`publication in this or a foreign country or in public use or on sale in this country,
`
`more than one year prior to the date of the application for patent in the United
`
`States.”
`
`26.
`
`I also understand that a claim is unpatentable as anticipated under pre-
`
`AIA § 102(e) if “the invention was described in (1) an application for patent,
`
`published under section 122(b), by another filed in the United States before the
`
`invention by the applicant for patent or (2) a patent granted on an application for
`
`patent by another filed in the United States before the invention by the applicant
`
`for patent, except that an international application filed under the treaty defined in
`
`section 351(a) shall have the effects for the purposes of this subsection of an
`
`application filed in the United States only if the international application
`
`designated the United States and was published under Article 21(2) of such treaty
`
`in the English language.”
`
`B. Obviousness
`I have been told that under pre-AIA 35 U.S.C. § 103(a), “[a] patent
`27.
`
`may not be obtained although the invention is not identically disclosed or
`
`described as set forth in section 102, if the differences between the subject matter
`
`sought to be patented and the prior art are such that the subject matter as a whole
`
`
`
`11
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`would have been obvious at the time the invention was made to a person having
`
`ordinary skill in the art to which said subject matter pertains. Patentability shall
`
`not be negatived by the manner in which the invention was made.”
`
`28. When considering the issues of obviousness under pre-AIA § 103, I
`
`have been told that I am to do the following:
`
`a.
`
`b.
`
`c.
`
`d.
`
`Determine the scope and content of the prior art;
`
`Ascertain the differences between the prior art and the claims at
`issue;
`
`Resolve the level of ordinary skill in the pertinent art; and
`
`Consider evidence of secondary indicia of non-obviousness (if
`available).
`
`29.
`
`I have been told that the relevant time for considering whether a claim
`
`would have been obvious to a person of ordinary skill in the art under pre-AIA
`
`§ 103 is the time of alleged invention.
`
`30.
`
`I have been told that obviousness is a determination of law based on
`
`underlying determinations of fact. I have been told that these factual
`
`determinations include the scope and content of the prior art, the level of ordinary
`
`skill in the art, the differences between the claimed invention and the prior art, and
`
`secondary considerations of non-obviousness.
`
`31. With respect to secondary indicia of non-obviousness, I have been
`
`told that such evidence may include the following:
`
`
`
`12
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`

`a. Commercial success: I have been told that a strong showing of
`commercial success that can be attributed to the merits of the
`invention should be considered an indication of non-obviousness.
`
`b. Copying: I have been told that evidence that if others have copied the
`patented invention, as opposed to a prior art device, which is an
`indication of non-obviousness.
`
`c. Long-standing problem or need: I have been told that evidence of a
`persistent problem or need in the art that was resolved by the patented
`invention is an indication of non-obviousness.
`
`d. Prior failure: I have been told that evidence that others have tried and
`failed to solve the problem is an indication of non-obviousness.
`
`e. Commercial acquiescence of competitors: I have been told that the
`willingness of industry to license the patent at issue is an indication of
`non-obviousness, though consideration must be given to
`distinguishing respect for the invention from a desire to avoid
`litigation.
`
`f. Skepticism: I have been told that evidence that those of ordinary skill
`were skeptical as to the merits of the invention, or even taught away
`from the invention, are indications of non-obviousness.
`
`g. Independent development: I have been told that evidence that others
`developed the claimed invention about the same time is an indication
`of obviousness. In contrast, I also have been told that failure to do so
`is an indication of non-obviousness.
`
`
`i. Unexpected results: I have been told that evidence that those of
`ordinary skill in the art were surprised by the capabilities of the
`claimed invention is an indication of non-obviousness.
`
`32.
`
`I have been told that any assertion of the above secondary indicia
`
`must be accompanied by a nexus between the merits of the invention and the
`
`evidence offered.
`
`
`
`13
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`33.
`
`I have been told that a reference may be combined with other
`
`references to disclose each element of the invention under pre-AIA § 103. I have
`
`been told that a reference may also be combined with the knowledge of a person of
`
`ordinary skill in the art and that this knowledge may be used to combine multiple
`
`references. I have also been told that a person of ordinary skill in the art is
`
`presumed to know the relevant prior art. I have been told that the obviousness
`
`analysis may take into account the inferences and creative steps that a person of
`
`ordinary skill in the art would employ.
`
`34.
`
`In determining whether a prior art reference could have been
`
`combined with another prior art reference or other information known to a person
`
`having ordinary skill in the art, I have been told that the following principles may
`
`be considered:
`
`a. A combination of familiar elements according to known methods is
`
`likely to be obvious if it yields predictable results;
`
`b. The substitution of one known element for another is likely to be
`
`obvious if it yields predictable results;
`
`c. The use of a known technique to improve similar items or methods in
`
`the same way is likely to be obvious if it yields predictable results;
`
`d. The application of a known technique to a prior art reference that is
`
`ready for improvement, to yield predictable results;
`
`
`
`14
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`

`e. Any need or problem known in the field and addressed by the
`
`reference can provide a reason for combining the elements in the
`
`manner claimed;
`
`f. A person of ordinary skill often will be able to fit the teachings of
`
`multiple references together like a puzzle; and
`
`g. The proper analysis of obviousness requires a determination of
`
`whether a person of ordinary skill in the art would have a “reasonable
`
`expectation of success”—not “absolute predictability” of success—in
`
`achieving the claimed invention by combining prior art references.
`
`35.
`
`I have been told that whether a prior art reference renders a patent
`
`claim unpatentable as obvious is determined from the perspective of a person of
`
`ordinary skill in the art. I have been told that, while there is no requirement that
`
`the prior art contain an express suggestion to combine known elements to achieve
`
`the claimed invention, a suggestion to combine known elements to achieve the
`
`claimed invention may come from the prior art as a whole or individually, as
`
`filtered through the knowledge of one skilled in the art. In addition, I have been
`
`told that the inferences and creative steps a person of ordinary skill in the art would
`
`employ are also relevant to the determination of obviousness.
`
`36.
`
`I have been told that, when a work is available in one field, design
`
`alternatives and other market forces can prompt variations of it, either in the same
`
`
`
`15
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`field or in another. I have been told that if a person of ordinary skill in the art can
`
`implement a predictable variation and would see the benefit of doing so, that
`
`variation is likely to be obvious. I have been told that, in many fields, there may
`
`be little discussion of obvious combinations, and in these fields market demand—
`
`not scientific literature—may drive design trends. I have been told that, when
`
`there is a design need or market pressure and there are a finite number of
`
`predictable solutions, a person of ordinary skill in the art has good reason to pursue
`
`those known options.
`
`37.
`
`I have been told that there is no rigid rule that a reference or
`
`combination of references must contain a “teaching, suggestion, or motivation” to
`
`combine references. But I also have been told that the “teaching, suggestion, or
`
`motivation” test can be a useful guide in establishing a rationale for combining
`
`elements of the prior art. I have been told that this test poses the question as to
`
`whether there is an express or implied teaching, suggestion, or motivation to
`
`combine prior art elements in a way that realizes the claimed invention, and that it
`
`seeks to counter impermissible hindsight analysis.
`
`VI. TECHNOLOGICAL BACKGROUND
`
`38. U.S. Patent No. 6,538,324 (Ex. 1001) addresses problems relating to
`
`diffusion barriers for use with copper interconnects that were heavily investigated
`
`in the 1990s because their solutions were necessary to scale semiconductor devices
`
`
`
`16
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`to smaller sizes. See, e.g., Ex. 1001, 1:13-19. As I discuss below, the ’324 patent’s
`
`solution had been taught in prior art. In my opinion, it was at best merely an
`
`obvious combination of existing technology used to solve the same problem.
`
`39. As background, semiconductor devices, such as transistors, are
`
`typically formed using layers of material deposited on a semiconductor substrate,
`
`such as silicon. Once formed, the semiconductor devices include electrical
`
`terminals that are interconnected by one or more metal wiring layers to form
`
`specific circuitry, for example, in a processor. A metal wiring layer is often
`
`deposited over an interlayer insulating layer, such as silicon dioxide, which
`
`separates the metal wiring layer from underlying layers of the semiconductor
`
`devices (such as MOSFETs).
`
`40. To my knowledge, at the time the ’324 patent was filed, those of
`
`ordinary skill in the art knew that copper was a desirable metal for the wiring layer
`
`as devices became smaller in size, since copper provided lower electrical resistivity
`
`relative to aluminum. As MOSFETs got smaller and faster, the interconnect delays
`
`became more and more important as a fraction of the overall delay; thus copper
`
`started supplanting the older aluminum based interconnect technology in silicon
`
`microelectronics. Ex. 1001, 1:13-19. But it was also known that “it is absolutely
`
`necessary for a semiconductor device having a copper wiring layer to have a
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`diffusion-barrier film for preventing diffusion of copper into an interlayer
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`17
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`insulating film formed between copper wiring layers.” Id., 1:26-30. It is also
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`important to prevent diffusion of copper into the silicon substrate where it can
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`create electrical defects which degrade MOSFET performance. Diffusion occurs
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`when atoms or molecules migrate from an area of higher concentration into an area
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`of lower concentration. Thus, I understand that the problem in the ’324 patent
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`concerned blocking the movement of copper from a wiring layer having a high
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`concentration of copper into an underlying insulating layer and semiconductor
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`devices. See id., 1:22-25 (explaining that copper has a high diffusion rate in silicon
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`and silicon dioxide, and if copper were to diffuse into a MOSFET formed on a
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`silicon substrate, it would induce a reduction in carrier lifetime in such a device,
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`and thus increase leakage current in MOSFETs and other devices).
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`41. The ’324 patent specification further explains it was known that the
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`diffusion barrier not only must prevent copper from diffusing out of the wiring
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`layer into underlying layers and devices, but also must provide good adhesion to
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`the copper wiring layer. Id., 2:13-15 (“As will be obvious to those skilled in the art,
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`the diffusion-barrier film is required to have high coverage as well as capability of
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`preventing copper diffusion and adhesion to copper.”); see also id., 1:30-33. The
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`specification acknowledges that several known copper-diffusion barrier films
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`existed at the time of the alleged invention. Id., 2:21-54, 7:52-57, FIGS. 1-3.
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`18
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`42. The purported invention is a two-layer diffusion barrier to prevent
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`copper diffusion and provide good adhesion to a copper wiring layer and the
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`interlayer insulating film.2 The bottom layer in the diffusion barrier is an
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`amorphous metal nitride to prevent copper diffusion. See, e.g., id., Abstract, 9:50-
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`52, 18:22-24. The top layer is a crystalline metal that contains nitrogen to provide
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`good adhesion to a copper wiring layer. See, e.g., id., Abstract, 9:49-50, 18:24-26.
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`The claims require the crystalline layer of the diffusion barrier to contain less
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`nitrogen than the amorphous layer. Id., 19:2-3.
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`43.
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`In my opinion, the two-layer diffusion barrier, combining known
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`crystalline and amorphous barrier layers, disclosed and claimed in the ’324 patent
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`was not new and non-obvious. As shown, for example, in FIG. 1 of the patent,
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`two-layer diffusion barriers for preventing copper diffusion were already known in
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`the art. Id., 7:51-52. It was also known that a crystalline film could provide good
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`adhesion to a copper wiring layer, although it exhibited a “low barrier
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`characteristic of preventing copper diffusion.” Id., 3:1-4, 3:14-19. And it was
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`2 The ’324 patent’s specification and claims refer to a barrier “film” (i.e., thin film)
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`having a multi-layered structure of first and second films. In this context, the words
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`“layer” and “film” are used interchangeably.
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`19
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`known that amorphous (non-crystalline) films provide a better barrier to copper
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`diffusion, though they do not adhere as well to copper. Id., 3:21-33.
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`44.
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`In my opinion, others in the field had already put these pieces together
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`to devise two-layer diffusion barriers with a crystalline layer for its known
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`characteristics of providing good adhesion to copper, and an amorphous layer for
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`its known property of preventing copper diffusion into underlying semiconductor
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`devices, e.g., incorporating the prior-art films in FIGS. 2 and 3 into the barrier
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`structure in FIG. 1. And more particularly, others had already made two-layer
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`diffusion barriers using a crystalline layer for providing good adhesion to copper
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`and an amorphous layer for preventing copper diffusion. They had also described
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`such two-layer diffusion barriers in which the amorphous layer was tantalum
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`nitride (TaNx) and the crystalline layer was a tantalum (Ta) metal containing
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`nitrogen. For example:
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`• U.S. Patent No. 5,893,752 (“Zhang”, Ex. 1004) discloses a two-layer
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`diffusion barrier having a bottom TaNx layer for preventing copper
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`diffusion and a top “tantalum-rich nitride film [that] is substantially
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`pure tantalum” for providing good adherence to a copper wiring layer.
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`Ex. 1004, Abstract, 2:29-40, 3:22-67, FIG. 8 (multi-layer diffusion
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`barrier 22 and 32, copper wiring layer 54 and 64)3, FIG. 4.
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`• U.S. Patent No. 6,887,353 (“Ding”, Ex. 1005), directed to the same
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`problem as the ’324 patent and Zhang, teaches that the TaNx layer in
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`Zhang would be an amorphous layer and the adjacent layer of
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`tantalum-rich nitride film would be crystalline. Ex. 1005, Abstract,
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`3:33-38, 7:66-8:4.
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`• Other prior art also discuss properties of Ta-based diffusion barriers at
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`different nitrogen contents for preventing copper diffusion. For
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`example, Sun et al., “Properties of reactively sputter-deposited Ta-N
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`thin films,” Thin Solid Films, vol. 236, nos. 1-2, pages 347-351
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`(1993) (“Sun”, Ex. 1007) discloses that “In substantial atomic
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`concentrations, nitrogen can also promote the formation of amorphous
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`metallic alloys with most early transition metals,” such as Ta, and the
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`resulting amorphous films exhibit an “absence of fast diffusion paths”
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`as compared with polycrystalline films. Ex. 1007 at 9.
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`3 Zhang teaches the copper seed film 54 and copper wiring film 64 may be
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`replaced with a single copper film. Ex. 1004, 5:35-38.
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`A. Diffusion Barrier Basics
`45. To my knowledge, copper had been widely used as interconnect
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`material in semiconductor devices due to its improved properties over aluminum,
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`such as smaller resistivity. See, e.g., Ex. 1005, 1:15-23 (“[c]opper offers a
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`significant improvement over aluminum as a contact and interconnect material.
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`For example, the resistivity of copper is about 1.67 µΩcm, which is only about half
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`of the resistivity of aluminum”). However, it had been recognized that “copper
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`diffuses rapidly into adjacent layers of SiO2 and silicon and needs to be
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`encapsulated.” Id., 1:60-62. To pr