IPR2015-01300 and IPR2015-01303
`
`
`
`
`
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`_____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`_____________
`
`ASML NETHERLANDS B.V., EXCELITAS TECHNOLOGIES CORP., AND
`QIOPTIQ PHOTONICS GMBH & CO. KG,
`Petitioners
`
`v.
`
`ENERGETIQ TECHNOLOGY, INC.,
`Patent Owner
`_____________
`
`Cases IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`_____________
`
`DECLARATION OF DONALD K. SMITH, PH.D.
`
`
`
`
`
`
`
`Energetiq Ex 2016, Page 1, IPR2015-01300, IPR2015-01303
`
`
`
`
`
`
`
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`_____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`_____________
`
`ASML NETHERLANDS B.V., EXCELITAS TECHNOLOGIES CORP., AND
`QIOPTIQ PHOTONICS GMBH & CO. KG,
`Petitioners
`
`v.
`
`ENERGETIQ TECHNOLOGY, INC.,
`Patent Owner
`_____________
`
`Cases IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`_____________
`
`DECLARATION OF DONALD K. SMITH, PH.D.
`
`
`
`
`
`
`
`Energetiq Ex 2016, Page 1, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`
`
`I, Donald K. Smith, Ph.D., hereby declare as follows:
`
`I.
`
`INTRODUCTION
`
`1.
`
`I am the President of Energetiq Technology, Inc. (“Energetiq”), which
`
`has its principal place of business at 7 Constitution Way, Woburn, MA 01801. I
`
`have worked at Energetiq in this capacity since 2004.
`
`2.
`
`I am a named inventor on United States Patent Nos. 8,525,138 (the
`
`“’138 patent”), 7,435,982 (the “’982 patent”), 8,309,943 (the “’943 patent”) and
`
`7,786,455 (the “’455 patent).
`
`3.
`
`I submit this declaration in support of Energetiq’s Patent Owner
`
`Response in connection with inter partes review proceedings IPR2015-01368,
`
`IPR2015-01277, IPR2015-01279, IPR2015-01300, IPR2015-01303, and
`
`IPR2015-01377. I have personal knowledge of the matters discussed below
`
`unless otherwise noted. If called upon as a witness, I could and would
`
`competently testify to the statements made herein.
`
`4.
`
`I received my Bachelor of Science in Physics from Davidson College
`
`in 1975, my M.S. in in electrical engineering from the University of Wisconsin in
`
`1976, and my Ph.D. in Electrical Engineering from the University of Wisconsin in
`
`1980. I have authored more than ten publications in peer reviewed scientific
`
`journals and am an inventor on more than 40 United States Patents and additional
`
`related foreign patents in the fields of vacuum technology, instrumentation,
`
`
`
`Energetiq Ex 2016, Page 2, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`turbomolecular pumps, ion trap mass spectrometers, plasma sources for etching
`
`and deposition, plasma-based reactive gas sources (such as ozone generators,
`
`atomic fluorine generators and atomic oxygen sources), plasma-based light
`
`sources, plasma devices and plasma chemical vapor deposition reactors. I have
`
`more than 35 years of professional experience in research and development in the
`
`areas of plasma physics and power electronics. I have 12 years of experience with
`
`inductively driven pulsed plasma light sources for EUV and DUV applications
`
`and patents on these devices. I have more than 10 years of experience in the
`
`research, design and functionality of high brightness laser-driven light sources
`
`such as those at issue in this proceeding. My curriculum vitae is attached hereto
`
`as Exhibit 2026.
`
`5. During my career spanning over 35 years, I have held many positions
`
`relating to plasma physics, including as a Research Scientist at the University of
`
`Wisconsin for one year and for 7 years at the MIT Plasma Fusion Center. In
`
`1988, I co-founded and served on the board of directors and as Vice President of
`
`Advanced Technology for Applied Science and Technology, Inc., ASTEX,
`
`developing plasma devices and reactive gas generators for semiconductor
`
`processing and chemical vapor deposition of diamond. Many tens of thousands of
`
`the products developed by me and by my team at ASTEX have been and continue
`
`to be installed in semiconductor fabs worldwide. On the strength of these
`
`
`
`
`
`Energetiq Ex 2016, Page 3, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`products, ASTEX became a successful public company and was acquired by MKS
`
`Instruments in 2001. I served as Vice-president and Chief Technology Officer at
`
`MKS between 2000 and 2004, when my colleagues and I founded Energetiq
`
`Technology, Inc.
`
`II. MATERIALS REVIEWED
`In preparing this declaration, I reviewed and considered the materials
`6.
`
`listed in Appendix A to this declaration. In addition, I reviewed the petitions,
`
`institution decisions, and supporting affidavits of Dr. Eden for each inter partes
`
`review proceeding, i.e. numbers IPR2015-01368, IPR2015-01277, IPR2015-
`
`01279, IPR2015-01300, IPR2015-01303, and IPR2015-01377.
`
`III. OVERVIEW OF ENERGETIQ AND ITS PATENTED
`TECHNOLOGY
`
`7. Energetiq is a leading developer and manufacturer of ultra-bright
`
`broadband light sources that enable the manufacture and analysis of nano-scale
`
`structures and products. Energetiq’s light source products are based on
`
`technology that generates high brightness light with high reliability, high stability,
`
`and long life, all in a compact package. Energetiq’s light sources are used for
`
`analytical spectroscopy, microscopy, and sensing in the life-sciences; lithography,
`
`metrology, inspection and photoresist development in semiconductor
`
`manufacturing; and for a variety of applications where synchrotron radiation and
`
`traditional arc-lamps have commonly been used.
`
`
`
`Energetiq Ex 2016, Page 4, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`For at least a decade prior to the invention, semiconductor
`
`8.
`
`manufacturing equipment used xenon or mercury arc lamps to produce light for
`
`use in wafer inspection, metrology and lithography systems. These lamps
`
`included an anode and cathode to generate an electrical discharge to provide
`
`power to a gas to generate and sustain a plasma which emitted light—they did not
`
`use lasers. Yet, arc lamps suffered from a number of shortcomings, including
`
`instability of the arc, undesirably short time to failure, and limits on how bright
`
`they could get, which severely constrained the accuracy and efficiency of the
`
`semiconductor manufacturing equipment that used them. In particular, the
`
`spectral brightness of xenon and mercury arc lamps (ordinarily in the range of
`
`about 1 to 9 mW/mm2-sr-nm) was limited by the maximum current density. (See
`
`M. W. P. Cann, Light Sources in the 0.15-20-μ Spectral Range, Vol. 8 No. 8
`
`Applied Optics 1645, 1658, Fig. 9 (1969) (Ex. 2072); (Solarz at 1:34-43 (Ex.
`
`2073).) If the current density was too high, it would melt the electrodes.
`
`9. Thus, for many years, the necessary improvements in semiconductor
`
`manufacturing tools had to come through steady improvements in components
`
`other than the light source, such as in the optics for collecting the light and the
`
`sensors for detecting and measuring light, rather than from the ability to deliver
`
`more light into smaller places. However, over time, the semiconductor industry
`
`
`
`Energetiq Ex 2016, Page 5, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`eventually demanded improvements in the brightness level of light sources
`
`beyond that which could be met by traditional arc lamps.
`
`10. For instance, in 2005, Energetiq was approached by an industry leader
`
`to see whether Energetiq could use a plasma to develop a high brightness light
`
`source. The industry required light that was at least many times higher brightness
`
`than that of existing arc lamps. Petitioner ASML agrees that “[s]ignificant . . .
`
`brightness improvements” are necessary over arc lamps. (U.S. Pub. No. US
`
`2013/0329204 A1 at ¶ 0008 (Ex. 2009).) Energetiq’s patented Laser Driven Light
`
`Source technology delivers a light source for these applications that provides
`
`brightness that is greater than Mercury or Xenon arc lamps.
`
`11.
`
`In particular, Energetiq’s patented technology provides a light source
`
`that does not rely on an electrical discharge to sustain a plasma, but instead uses a
`
`laser to sustain a plasma under particular conditions to produce a high brightness
`
`light for semiconductor manufacturing applications, as shown below:
`
`
`
`
`
`Energetiq Ex 2016, Page 6, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`
`
`
`12. By way of brief non-limiting summary, Energetiq’s patented laser-
`
`driven light source technology operates by providing, to a gas disposed within a
`
`pressurized chamber, laser energy (e.g., at a wavelength within 10 nm of a strong
`
`absorption line of the gas). The laser energy sustains a plasma, which produces a
`
`plasma-generated light (broadband output). The light of Energetiq’s laser-driven
`
`light source technology offers improved characteristics over light generated by
`
`earlier light sources, including, for example, higher brightness, broader
`
`wavelength range, and significantly longer operating life. For example, an
`
`experiment described in the patent showed a brightness of 8 to 18W/(mm2-sr) over
`
`
`
`Energetiq Ex 2016, Page 7, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`the 200-400 nm wavelength band, which is equivalent to a spectral brightness of
`
`40 to 90 mW/(mm2-sr-nm)—i.e., four to ten times the brightness of existing
`
`mercury and xenon arc lamps. (See, e.g., ‘138 Patent at Fig. 3.)
`
`IV. DEFINITION OF PERSON OF ORDINARY SKILL IN THE ART
`I believe that the level of ordinary skill in the art is a master of science
`13.
`
`degree in physics, electrical engineering or an equivalent field, and 4 years of
`
`work or research experience in plasmas and a basic understanding of lasers; or a
`
`Ph.D. degree in physics, electrical engineering or an equivalent field and 2 years
`
`of work or research experience in plasmas and a basic understanding of lasers.
`
`14. The main difference between Energetiq’s definition and Petitioners’
`
`(adopted in the Institution Decision) is that Petitioners definition requires
`
`expertise in lasers—knowledge that the active workers in the field did not have.1
`
`Energetiq’s definition is fully supported, taking into account the experience of
`
`
`1 I understand that Petitioners proposed definition is “a Ph.D. in physics, electrical
`
`engineering, or an equivalent field, and 2–4 years of work experience with lasers
`
`and plasma, or a master’s degree in physics, electrical engineering, or an
`
`equivalent field, and 4–5 years of work experience with lasers and plasma.” ‘138
`
`Petition at 3; ‘943 Petition at 3.
`
`
`
`Energetiq Ex 2016, Page 8, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`active workers in the field, and further informed by other pertinent factors that
`
`determine the level of skill of an ordinary artisan.
`
`A. Active Workers In The Field And The Inventor
`15. Energetiq’s R&D staff at the time of the invention typifies the
`
`educational level of active workers in the field. At the time of the invention,
`
`when they were hired, 4 out of 7 individuals in Energetiq’s R&D staff had a basic
`
`understanding of lasers, which is consistent in scope with Energetiq’s proposed
`
`definition—the rest had no experience in lasers. None had the lasers expertise
`
`Petitioners propose.
`
`B. Problems In The Art, Prior Art Solutions, Rapidity with Which
`Innovations are Made, and Sophistication of the Technology
`
`16. The problems encountered in the art included the need for a high
`
`brightness light sources for applications such as semiconductor manufacturing.
`
`(See, e.g., ’138 patent, at 1:38-62.) Prior art solutions used by ordinary artisans
`
`consisted of arc lamps which used electrodes to excite gas in a chamber and
`
`produce light – they did not use lasers. Energetiq’s invention enabled the sale of
`
`the first commercial laser driven light source—a market that did not exist prior to
`
`the invention. Innovations had been slow and incremental, consisting of
`
`improvements to existing arc lamps. (Id.) Thus, requiring laser expertise—as
`
`proposed by Petitioners—is incorrect and unsupported.
`
`
`
`Energetiq Ex 2016, Page 9, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`
`V. OVERVIEW OF GÄRTNER
`17. Gärtner is a 1985 French patent application that describes an
`
`incomplete system which appears to relate to a radiation source for optical
`
`devices.
`
`18. As far as I can determine, Gärtner discloses technology that was never
`
`developed into a commercial product. Indeed, Gärtner is so far removed from
`
`mainstream knowledge that it was unknown to me, and had never been cited by
`
`the Patent Office, until Petitioners identified it to Energetiq in the heat of this
`
`dispute. Since then, the Patent Office has issued two of Energetiq’s patents with
`
`Gartner in front of it.
`
`19. Gärtner describes using a CO2 laser to try to generate a plasma
`
`discharge. It is patentably important that Gärtner uses a CO2 laser, because while
`
`Gärtner does not expressly disclose its wavelength, it is well-known that CO2
`
`lasers produce energy at a wavelength between 9,400 and 10,600 nm—which far
`
`exceeds the wavelength ranges contemplated by Energetiq’s patents (e.g., within
`
`10 nanometers of certain strong absorption lines of xenon at 980 nm, 895 nm, 882,
`
`nm, or 823 nm).
`
`20. Gärtner does not describe or suggest using any other laser, let alone a
`
`short wavelength laser, to sustain a plasma. The wavelength is important to the
`
`invention – this is not a technology where one would just swap one type of laser
`
`
`
`Energetiq Ex 2016, Page 10, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`for any other type, where wavelength is irrelevant. At the time of the invention,
`
`those of ordinary skill would not have expected the results Energetiq obtained by
`
`using a short wavelength laser.
`
`VI. OPINIONS REGARDING CHALLENGED CLAIMS IN THE ’138
`PATENT
`A. Claim Interpretation of “Light”
`Independent claim 1 recites the term “light.” I understand that the
`21.
`
`Board has construed the term to mean “electromagnetic radiation in the ultraviolet
`
`(“UV”), extreme UV, vacuum UV, visible, near infrared, middle infrared, or far
`
`infrared regions of the spectrum, having wavelengths within the range of 10 nm to
`
`1,000 μm.” While this construction is a fair start, it is my opinion that the term
`
`“light” should more properly be construed to mean “electromagnetic energy.”
`
`However, my opinions regarding the challenged claims do not turn on the
`
`meaning of the term “light,” and I am applying the adopted construction where
`
`appropriate throughout this declaration. But, while the Board adopted this
`
`construction here, in other parallel IPR proceedings, it adopted a different
`
`construction with wavelength ranges as proposed by Petitioners. That
`
`construction is wrong in my view.
`
`B. Claim Interpretation of “Sustain”
`22. The term “sustain” is used in the claims to contrast the behavior of the
`
`plasma, from other terms relating to the plasma, such as “generate” or “initiate.”
`
`
`
`Energetiq Ex 2016, Page 11, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`An illustrative use of this term appears in claim 1, which states: “[a] laser
`
`configured to provide energy … to sustain a plasma…” (’138 patent, claim 1
`
`(‘1368 IPR, Ex. 1001).) The ’138 patent discusses that “the light source 700
`
`includes an ignition source…that, for example, generates an electrical discharge
`
`in the chamber 728…to ignite the ionizable medium. The laser source 704 then
`
`provides laser energy to the ionized medium to sustain the plasma 732 which
`
`generates the high brightness light 736.” (Id. at 20:64-21:4 (emphases added)
`
`(‘1368 IPR, Ex. 1001).)
`
`23. The distinction between “igniting” or “generating” a plasma and
`
`“sustaining” a plasma is brought into sharper focus with reference to other
`
`embodiments in the ’138 patent, in which laser energy is both “igniting” and
`
`“sustaining” the plasma. In those instances, each term, i.e., ‘ignite’ and ‘sustain,’
`
`has independent meaning with respect to the effect that the laser is having on the
`
`plasma. See id. at 20:58-62 (“The laser beam 724 passes through the chamber
`
`728…where the plasma 732 exists (or where it is desirable for the plasma 732 to
`
`be generated by the laser 724 and sustained)…[T]he ionizable medium is ignited
`
`by the laser beam 724.”). Similarly, claim 1 requires “an ignition source” and a
`
`“laser…to sustain a plasma within the chamber…” (Id. at claim 1.)
`
`24.
`
`I believe that an ordinary artisan would understand that to “sustain a
`
`plasma” means to maintain the plasma without interruption. Petitioners’ expert
`
`
`
`Energetiq Ex 2016, Page 12, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`acknowledges he understood the term “sustain” to mean “to maintain the
`
`existence of” such that the “plasma would continue to exist.” (Eden Tr. 66:16-19;
`
`68:18-21 (Ex. 2006).) This understanding is also reflected in common technical
`
`references in the field. (See, e.g., Keefer at 169 (“With the advent of continuous,
`
`high-power carbon dioxide lasers, it became possible to sustain a plasma in a
`
`steady-state…”) (Ex. 2082).)
`
`25. The term “laser sustained plasma” is frequently used in the art to
`
`describe a plasma that generates steady-state light output, in contrast to plasma
`
`sources that exhibit other modes of operation, such as “pulsed” plasmas existing
`
`only transiently, and to which the term sustain would not be not applied. (See id.
`
`at 172 (“High-energy pulsed lasers can generate plasma breakdown directly within
`
`a gas that results in a transient expanding plasma similar to an explosion.”) (Ex.
`
`2082).
`
`26. The customary and ordinary meaning of the term is also reflected in
`
`and consistent with dictionary definitions. Webster’s Third New International
`
`Dictionary (2002) defines “sustain” to mean “to cause to continue (as in existence
`
`or a certain state or in force or intensity): to keep up esp. without interruption,
`
`diminution, or flagging : maintain.” (Webster’s Third New Int’l Dict. of the
`
`English Language, Unabridged, “Sustain,” 2304 (2002) (Ex. 2023); see also, The
`
`Merriam-Webster Dictionary 722 (2004) (sustain, “to keep going: prolong”) (Ex.
`
`
`
`Energetiq Ex 2016, Page 13, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`2024); The American Heritage Dictionary of the English Language 1744 (4th ed.
`
`2006) (sustain, “To keep in existence; maintain.”) (Ex. 2025).) Thus, I believe
`
`that “sustain” should be construed to mean “maintain without interruption.”
`
`C. Overview of Beterov
`27. Beterov is a scholarly article that considers the role of atomic
`
`resonance in forming plasmas. Beterov shows the manner in which a plasma may
`
`be formed in an atomic vapor, such as a sodium metal vapor, by tuning a laser to a
`
`resonant excitation frequency for the atoms, and then allowing the resonantly
`
`excited atoms to ionize via the process of collisions between excited atoms (a
`
`process called “associative ionization”). Beterov discusses multiple lasers using
`
`short wavelengths.
`
`28. Notably, Beterov’s disclosure is devoid of any discussion that would
`
`connect plasmas that are purportedly generated to any application for which a
`
`bright broadband light source would be required. Instead, the discussion in
`
`Beterov appears to be directed to “realization and application of the optogalvanic
`
`effect” and to “study the kinetics of nonequilibrium plasma, to study elementary
`
`processes in a plasma and in a gas, [and] to detect radiation having a certain
`
`wavelength, etc.” (Beterov at 552 (‘1368 IPR, Ex. 1006).) I believe that a person
`
`of ordinary skill in the art, seeking to improve on the brightness of prior art light
`
`
`
`Energetiq Ex 2016, Page 14, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`sources (e.g., arc lamps) would not have turned to Beterov’s academic disclosure
`
`directed to disparate applications.
`
`D. An Ordinary Artisan Would Not Have Redesigned Gartner with a
`Short Wavelength Laser
`
`29. Petitioners fail to recognize that the state of the art expressly taught
`
`away from using short wavelength lasers, such as those discussed in Beterov, to
`
`sustain a plasma and produce bright light—which is the purpose of the ‘138
`
`invention.
`
`30.
`
`In 2006, when this invention was disclosed, I believe that an ordinary
`
`artisan would not have been motivated to replace Gärtner’s CO2 laser with a short
`
`wavelength laser such as Beterov’s, because doing so would have been contrary to
`
`the conventional understanding in the field of the “inverse bremsstrahlung”
`
`absorption mechanism.
`
`31.
`
`Indeed, Energetiq was the first to discover that the industry’s
`
`understanding of laser plasma heating was incomplete. The “inverse
`
`bremsstrahlung” absorption mechanism, which governed the traditional
`
`understanding of laser-sustained plasma interactions before Energetiq’s invention,
`
`is “one of the fundamental interactions in optical physics” that an ordinary artisan
`
`at the time of the invention would have been aware of. (Eden Tr. at 97:6-14.)
`
`32. According to the “inverse bremsstrahlung” absorption mechanism, it
`
`was believed at the time of the invention that the laser wavelength played a
`
`
`
`Energetiq Ex 2016, Page 15, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`significant role in sustaining the plasma. Inverse bremsstrahlung is a process in
`
`which free electrons in plasma absorb energy from an incident laser beam during
`
`collisions with ions and neutral atoms. (D. Keefer, “Laser Sustained Plasmas,”
`
`Chapter 4, in Radziemski et al., Laser-Induced Plasmas and Applications 173
`
`(1989) (Ex. 2082) (“Keefer”).) The amount of energy absorbed by the plasma is
`
`based on the absorption coefficient, which is given by:
`
`
`
`𝛼=�𝜋𝜋𝜔�2𝑛𝑆0𝐺𝑘𝑘 �1−𝑒−ℏ𝜔/𝑘𝑘ℏ𝜔/𝑘𝑘 �
`
`Eq. (1)
`
`wherein ω, frequency, is given by ω=(2πc)/(λ) and c is the speed of light. (Keefer
`
`at 173 (Ex. 2082)) Relatedly, the absorption length of the plasma is equal to 1/α.
`
`Because energy absorbed by the plasma is proportional to the square of the
`
`wavelength (λ2) of the light being absorbed, it was believed that as the wavelength
`
`became shorter, the energy absorbed by the plasma would decrease. Less energy
`
`absorbed means lower brightness.
`
`33. Similarly, because the absorption length of the plasma is
`
`approximately proportional to 1/(λ2) of the light being absorbed, it was believed
`
`that as the laser wavelength became shorter, the absorption length (and resulting
`
`plasma size) would increase. Because brightness is a measure of power radiated
`
`by a source per unit surface area, longer (and larger) plasma again means lower
`
`brightness.
`
`
`
`Energetiq Ex 2016, Page 16, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`34. For many years, these principles guided the work in the field and, as a
`
`result, long wavelength CO2 lasers, as in Gärtner, which have a wavelength
`
`λ=10,600 nm, were the preferred source for laser-sustained plasmas – because
`
`they had a long wavelength. By the time of the invention, numerous references
`
`recognized the inverse bremsstrahlung mechanism, and expressly taught away
`
`from using a short wavelength laser.
`
`35. Energetiq was the first to recognize that, even though short
`
`wavelength lasers were supposed to produce lower absorption and larger plasma
`
`according to inverse bremsstrahlung, they instead were able to sustain small,
`
`bright plasmas in higher pressure gases. It was only after Energetiq’s invention
`
`that researchers, trying to understand this phenomenon, recognized that short
`
`wavelength lasers produced significant additional heating due to absorption by
`
`bound-bound electrons which could sustain a plasma, even though these lasers
`
`produced lower absorption for free electrons under the inverse bremsstrahlung
`
`mechanism. That is, after Energetiq made its invention, it was discovered that for
`
`short wavelength lasers, the plasma heating due to bound-bound electron
`
`absorption took dominance over inverse bremsstrahlung.
`
`36. Applying the inverse bremsstrahlung principles, energy absorbed by a
`
`plasma is approximately proportional to the square of the wavelength (λ2) of the
`
`light being absorbed. Thus, conventional wisdom understood that as the
`
`
`
`Energetiq Ex 2016, Page 17, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`wavelength is made shorter, the energy absorbed by the plasma decreases. Less
`
`energy absorbed means lower brightness. By way of example, under the inverse
`
`bremsstrahlung Eq. 1 (above), energy absorption is approximately 100 times
`
`stronger for a CO2 laser (λ=10,600 nm) than a NIR laser (λ=1,060 nm).
`
`37. That this was conventional wisdom is clear – numerous references
`
`recognized this relationship between laser wavelength and energy absorption and
`
`expressly discouraged incorporating shorter wavelength lasers, like that of
`
`Beterov, to sustain a bright plasma. (See, for example, Cremers at 671 (1985)
`
`(Ex. 2081) (cautioning that “unsuccessful attempts were made to generate the
`
`[plasma discharge] with up to 60W of 1.06-μm radiation from a multimode cw-
`
`Nd:YAG laser. Because laser heating of a plasma via inverse bremsstrahlung
`
`varies as 𝜆2…, the failure to form the COD was probably due to the 100 times
`
`lower absorption of the plasma at 1.06 μm compared to 10.6 μm.”); Cross at 5:40-
`
`52 (1988) (Ex. 1021) (cited by Petitioners, that “cw-laser sources [continuous-
`
`wave] having shorter wavelengths …are absorbed less effectively, and would
`
`require substantially greater cw-laser output power levels to sustain the plasma.”
`
`Thus, “carbon dioxide lasers [as in Gärtner] have been used since the output
`
`therefrom is readily absorbed by plasmas.”); Keefer at 178 (Ex. 2082) (also cited
`
`by the Petitioner, that for “LSP [laser-sustained plasma], ℏω≪kT and the
`
`absorption is approximately proportional to the square of the laser wavelength.
`
`
`
`Energetiq Ex 2016, Page 18, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`Due to this strong wavelength dependence, all of the reported experimental results
`
`for the LSP have been obtained using the 10.6 µm wavelength carbon dioxide
`
`laser [as in Gärtner].”)
`
`38. All these references attribute the lack of adequate plasma generation
`
`to an expected lower absorption rate of short wavelength lasers. In fact, this
`
`remained the “conventional wisdom” through the date of the invention, despite
`
`other advances in laser technology. Energetiq herein supplies evidence to
`
`document that it remained the conventional wisdom until the invention – Raizer
`
`(1991, 1997), Toumanov (2003) and Fridman (2004), all published “between 1989
`
`and 2006.”
`
`39.
`
`In 1991 and then, again in 1997, a textbook by Raizer described that
`
`“[f]ortunately, the wavelength of the IR radiation of CO2 lasers is large, since the
`
`absorption coefficient of plasma for light falls off steeply with frequency [which is
`
`1/ λ].” (Raizer 1991 at 306 (Ex. 2007)); Raizer 1997 at 306 (Ex. 2011).) Raizer
`
`observed that, at pressure of 1 atm, the maximum value of the absorption
`
`coefficient for a CO2 laser (λ=10.6μm) is 0.85 cm-1. On the other hand, the
`
`maximum value of the absorption coefficient for a neodymium laser (λ=1.06μm)
`
`is 6x10-3 cm, which is 140 times less. Thus, Raizer warned that “these figures
`
`show clearly why short-wave radiation is not advantageous for sustaining a
`
`plasma: the transparency of the plasma is too great.” Id.
`
`
`
`Energetiq Ex 2016, Page 19, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`In 2003, a textbook by Toumanov again recognized that “[t]he
`
`40.
`
`absorption coefficient of the light radiation in plasma falls abruptly with raising
`
`frequency. Therefore the generation of the optical discharge in the visible light
`
`frequency range would require a power greater than that of CO2 lasers by a factor
`
`of 102-103.” I.N. Toumanov, Plasma and High Frequency Processes for
`
`Obtaining and Processing Materials in the Nuclear Fuel Cycle 60 (2003) (Ex.
`
`2045).) And, in 2004, and then again in 2011, a textbook by Fridman—which
`
`Petitioners’ expert conceded had “universal” “ideas” (Eden Tr. 231:1-8)—taught
`
`that “[l]ight absorption coefficient in plasma significantly decreases with growth
`
`of electromagnetic wave frequency [frequency is the inverse of wavelength]….”
`
`(Fridman 2004 at 619 (Ex. 2022); Fridman et al., Plasma Physics and Engineering
`
`639 (2nd ed. 2011) (Ex. 2046.).
`
`41. Thus, the conventional wisdom at the time of the invention was that
`
`the inverse bremsstrahlung absorption mechanism discouraged the use of short
`
`wavelength lasers such as Beterov’s to sustain a high brightness plasma due to the
`
`expected lower absorption rate of shorter wavelength lasers.
`
`42. When this invention was made, I believe that an ordinary artisan
`
`would not have been motivated to replace Gärtner’s CO2 laser with Beterov’s
`
`short wavelength laser because this would have led to a larger plasma, resulting in
`
`lower brightness.
`
`
`
`Energetiq Ex 2016, Page 20, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`43. Applying the inverse bremsstrahlung principles, the absorption length
`
`of the plasma is approximately proportional to 1/(λ2) of the light being absorbed.
`
`Thus, the conventional wisdom was that as the laser wavelength is made shorter,
`
`the absorption length (and resulting plasma size) is expected to increase. Because
`
`brightness is a measure of power radiated by a source per a unit surface area (and
`
`solid angle), a longer (and larger) plasma also means lower brightness. By way of
`
`example, under the inverse bremsstrahlung Eq. 1 (above), the absorption length is
`
`approximately 100 times longer for a NIR laser (λ=1,060 nm) than a CO2 laser
`
`(λ=10,600 nm).
`
`44. Here, too, contemporaneous references recognized that a shorter
`
`wavelength laser such as those of Beterov would have resulted in a larger plasma
`
`and expressly discouraged incorporating shorter wavelength lasers to sustain a
`
`high brightness plasma. For example, Keefer (1989) stated that “[d]ue to this
`
`strong wavelength dependence, all of the reported experimental results for the
`
`LSP have been obtained using the 10.6 micrometer wavelength carbon dioxide
`
`laser [as in Gärtner]. Since the length scale for the plasma is of the order of the
`
`absorption length, the length of the plasma and the power required to sustain it
`
`would be expected to increase dramatically for shorter wavelength lasers.”
`
`(Keefer at 178 (Ex. 2082).) Similarly, Raizer (1991, 1997) observed that, at a
`
`pressure of one atmosphere, the minimum absorption length of the laser radiation
`
`
`
`Energetiq Ex 2016, Page 21, IPR2015-01300, IPR2015-01303
`
`
`
`IPR2015-01300 and IPR2015-01303
`U.S. Patent No. 7,435,982
`for a CO2 laser (λ=10.6μm) is 1.2 cm while the minimum absorption length for a
`
`neodymium laser (λ=1.06μm) is 170 cm. Raizer then concluded that “these
`
`figures show clearly why short-wave radiation is not advantageous for sustaining
`
`a plasma: the transparency of the plasma is too great.” (Raizer 1991 at 308 (Ex.
`
`2007).); Raizer 1997 at 308 (Ex. 2011).).
`
`45. Thus, well known physics principles—e.g., the inverse
`
`bremsstrahlung—as well as both Keefer (1989) and Raizer (1991, 1997),
`
`expressly discouraged the use of short wavelength lasers to sustain bright plasma
`
`as it would lead to a larger plasma resulting in lower brightness light.
`
`46. Energetiq discovered that, despite the implications of the widely
`
`accepted inverse-bremsstrahlung excitation mechanism, a shorter wavelength laser
`
`would penetrate to and excite the electrons and atoms of the plasma, sustain the
`
`plasma, and produce a higher brightness light.
`
`47.
`
`In fact, Energetiq’s discovery eventually led to the recognition that
`
`short wavelength lasers produced significant additional absorption for bound
`
`electrons even though they produced lower absorption for free electrons under
`
`inverse bremsstrahlung.
`
`48. Energetiq’s invention and contributions to the field of plasma
`
`generation have been repeatedly praised by numerous researchers. For example,
`
`Zimakov noted that “[i]t was treated for a long time since COD [continuous
`
`
`
`Energetiq Ex 2016, Page 22, IPR2015-01300, IPR2015-01303
`
`
`
Accessing this document will incur an additional charge of $.
After purchase, you can access this document again without charge.
Accept $ Charge
Still Working On It
This document is taking longer than usual to download. This can happen if we need to contact the court directly to obtain the document and their servers are running slowly.
Give it another minute or two to complete, and then try the refresh button.
A few More Minutes ... Still Working
It can take up to 5 minutes for us to download a document if the court servers are running slowly.
Thank you for your continued patience.
This document could not be displayed.
We could not find this document within its docket. Please go back to the docket page and check the link. If that does not work, go back to the docket and refresh it to pull the newest information.
Your account does not support viewing this document.
You need a Paid Account to view this document. Click here to change your account type.
Your account does not support viewing this document.
Set your membership
status to view this document.
With a Docket Alarm membership, you'll
get a whole lot more, including:
- Up-to-date information for this case.
- Email alerts whenever there is an update.
- Full text search for other cases.
- Get email alerts whenever a new case matches your search.
One Moment Please
The filing “” is large (MB) and is being downloaded.
Please refresh this page in a few minutes to see if the filing has been downloaded. The filing will also be emailed to you when the download completes.
Your document is on its way!
If you do not receive the document in five minutes, contact support at support@docketalarm.com.
Sealed Document
We are unable to display this document, it may be under a court ordered seal.
If you have proper credentials to access the file, you may proceed directly to the court's system using your government issued username and password.
Access Government Site
