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.
`
`Case IPR2016-00579
`
`
`
`DECLARATION OF HOWARD MILCHBERG, PH.D.
`REGARDING U.S. PATENT NO. 7,786,455
`CLAIMS 28-34
`
`ASML 1503
`
`
`
`
`
`
`
`

`
`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`TABLE OF CONTENTS
`
`
`V. 
`
`I. 
`BACKGROUND ............................................................................................. 1 
`LEGAL PRINCIPLES ..................................................................................... 4 
`II. 
`PERSON OF ORDINARY SKILL IN THE ART .......................................... 5 
`III. 
`IV.  OVERVIEW OF THE ’455 PATENT ............................................................ 6 
`A. 
`Summary of the Prosecution History .................................................... 8 
`CLAIM CONSTRUCTION ............................................................................ 9 
`A. 
`“Light source” ....................................................................................... 9 
`B. 
`“High brightness light” ........................................................................ 11 
`C. 
`“Means for providing electromagnetic energy to the ionized gas
`within the chamber to produce a plasma that generates a high
`brightness light.” ................................................................................. 14 
`(a)  Function ........................................................................................ 14 
`(b)  Structure ....................................................................................... 14 
`VI.  THE CHALLENGED CLAIMS ARE INVALID ......................................... 15 
`A. 
`Laser Sustained Plasma Light Sources Were Known Long
`Before the Priority Date of the ’455 Patent ......................................... 15 
`Using a dichroic mirror to separate light of different
`wavelengths was well known in the art. .............................................. 18 
`VII.  GROUNDS FOR FINDING THE CHALLENGED CLAIMS INVALID ... 19 
`A.  Ground 1: Claim 28 is unpatentable over Gärtner .............................. 19 
`(a)  Gärtner was not considered by the Patent Office during
`examination .................................................................................. 20 
`(b)  Claim 28 is anticipated by Gärtner ............................................... 20 
`Ground 2: Claims 29, 30, and 32 are unpatentable over Gärtner
`in view of Ershov ................................................................................ 25 
`(a)  Gärtner and Ershov are each prior art that was not considered by
`the Patent Office during examination. .......................................... 25 
`(b)  Dependent Claim 29 is unpatentable over Gärtner in view of
`Ershov ........................................................................................... 26 
`
`B. 
`
`B. 
`
`1
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`

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`C. 
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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`(c)  Dependent Claim 30 is unpatentable over Gärtner in view of
`Ershov ........................................................................................... 28 
`(d)  Dependent Claim 32 is unpatentable over Gärtner in view of
`Ershov ........................................................................................... 28 
`(e)  Reasons to combine ...................................................................... 29 
`Ground 3: Claims 31 and 33 are unpatentable over Gärtner in
`view of Ershov further in view of Ito .................................................. 34 
`(a)  Gärtner, Ershov, and Ito are each prior art that was not considered
`by the Patent Office during examination. ..................................... 34 
`(b)  Dependent Claim 31 is unpatentable over Gärtner in view of
`Ershov and further in view of Ito ................................................. 34 
`(c)  Dependent Claim 33 is unpatentable over Gärtner in view of
`Ershov and further in view of Ito ................................................. 38 
`(d)  Reasons to combine ...................................................................... 40 
`D.  Ground 4: Claim 34 is unpatentable over Gärtner in view of Ito ....... 45 
`(a)  Claim 34 is obvious over Gärtner in view of Ito .......................... 45 
`VIII.  RESPONSE TO ARGUMENTS RAISED BY PATENT OWNER IN ITS
`PRELIMINARY INJUNCTION MOTION .................................................. 49 
`A. 
`Patent Owner’s Arguments Regarding the Content of the Prior
`Art ........................................................................................................ 50 
`(a)  High Brightness Light .................................................................. 50 
`Patent Owner’s Arguments Regarding Objective Indicia of
`Non-Obviousness ................................................................................ 54 
`IX.  AVAILABILITY FOR CROSS-EXAMINATION ...................................... 55 
`X. 
`RIGHT TO SUPPLEMENT .......................................................................... 56 
`XI. 
`JURAT ........................................................................................................... 57 
`
`
`B. 
`
`
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`
`2
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`

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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`I, Howard Milchberg, Ph.D., declare as follows:
`
`1. My name is Howard Milchberg.
`
`I.
`
`BACKGROUND
`2.
`
`I am a Professor of Physics and Electrical and Computer Engineering
`
`at the University of Maryland in College Park, Maryland.
`
`3.
`
`I received a B.Eng. in Engineering Physics from McMaster University
`
`in Hamilton, Ontario, Canada in 1979. I received a Ph.D. in Astrophysical
`
`Sciences from Princeton University in Princeton, New Jersey in 1985.
`
`4.
`
`After receiving my doctorate, I worked at AT&T Bell Laboratories in
`
`as a postdoc from 1985 to 1987.
`
`5.
`
`In 1988, I was appointed Assistant Professor in the Department of
`
`Electrical and Computer Engineering at the University of Maryland. In 1993, I
`
`became Associate Professor in this same department, and in 1995, I became
`
`Professor in this department. I am currently Professor in the Departments of
`
`Physics and Electrical and Computer Engineering.
`
`6.
`
`Since joining the faculty of the University of Maryland in 1988, I
`
`have been engaged in research in: nonlinear optics; laser and optical physics; the
`
`interaction of intense electromagnetic fields with atoms, ions, gases, solids, and
`
`plasmas; the generation and application of coherent and incoherent short
`
`wavelength radiation; and laser-based acceleration of charged particles. My
`
`1
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`

`
`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`research has been featured in Physical Review Letters, Optics Letters, Optics
`
`Express, Physical Review X; Optica; Physics of Plasmas; Applied Physics Letters,
`
`and the Journal of the Optical Society of America, and has received popular press
`
`coverage in the Washington Post, Le Monde, Science News, Physics Today,
`
`Nature, Smithsonian Magazine, and Gizmodo, among others.
`
`7.
`
`I taught/teach courses in electromagnetic theory, quantum mechanics,
`
`laser science, and laser-plasma interactions among others. I have directed the
`
`dissertations of 17 individuals who received the Ph.D. degree in Physics or
`
`Electrical and Computer Engineering.
`
`8.
`
`I have authored or co-authored over 120 peer-reviewed academic
`
`publications in the fields of physics and applied physics.
`
`9.
`
`From 1979 through 1984, I was a NSERC Postgraduate Fellow
`
`through the National Research Council Canada. From 1988 through 1993, I was a
`
`National Science Foundation Presidential Young Investigator. I am fellow of the
`
`American Physical Society and the Optical Society of America. In 2005, I
`
`received the University of Maryland Distinguished Scholar-Teacher award. In
`
`2005, I also received the American Physical Society Award for Excellence in
`
`Plasma Physics Research.
`
`10.
`
`I am a named inventor on one United States patent and have patent
`
`applications pending both in the United States and abroad.
`
`2
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`

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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`11. A copy of my curriculum vitae is attached as Appendix A.
`
`12.
`
`I have reviewed the specification and claims of U.S. Patent No.
`
`7,786,455 (“the ’455 patent,” Ex. 1501). I have been informed that the ’455 patent
`
`claims priority to U.S. Application No. 11/395,523, filed on March 31, 2006, now
`
`U.S. Patent No. 7,435,982 (the “’982 patent”).
`
`13.
`
`I have also reviewed the following references, all of which I
`
`understand to be prior art to the ’455 patent:
`
` French Patent Publication No. FR2554302A1 (with English
`Translation), published May 3, 1985 (“Gärtner,” Ex. 1504).
`
` Japanese Patent Publication No. JPH04-144053A, (with English
`Translation), published May 18, 1992 (“Ito,” Ex. 1505).
`
` U.S. Patent Publication No. 2006/0192152, filed August 31, 2005,
`published August 31, 2006 (“Ershov,” Ex. 1516).
`
`14.
`
`I have also reviewed the exhibits cited in this Declaration, as well as
`
`
`
`
`
`the Declaration of Dr. J. Gary Eden in support of an IPR petition directed to the
`
`same patent. (Case No. IPR2015-01279 (Exhibit 1003).)
`
`15.
`
`I am being compensated at my normal consulting rate for my work.
`
`16. My compensation is not dependent on and in no way affects the
`
`substance of my statements in this Declaration.
`
`17.
`
`I have no financial interest in the Petitioners. I similarly have no
`
`financial interest in the ’455 patent.
`
`3
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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`
`II. LEGAL PRINCIPLES
`18.
`I have been informed that a claim is invalid as anticipated under 35
`
`U.S.C. § 102(a) if “the invention was known or used by others in this country, or
`
`patented or described in a printed publication in this or a foreign country, before
`
`the invention thereof by the applicant for patent.” I have also been informed that a
`
`claim is invalid as anticipated under 35 U.S.C. § 102(b) if “the 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.” Further I have been informed that a
`
`claim is invalid as anticipated under 35 U.S.C. § 102(e) if “the invention was
`
`described in … an application for patent, published under section 122(b), by
`
`another filed in the United States before the invention by the applicant for patent
`
`….” It is my understanding that for a claim to be anticipated, all of the limitations
`
`must be present in a single prior art reference, either expressly or inherently.
`
`19.
`
`I have been informed that a claim is invalid as obvious under 35
`
`U.S.C. § 103(a):
`
`
`
`4
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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`if the differences between the subject matter sought to be patented and
`the prior art are such that the subject matter as a whole would have
`been obvious at the time the invention was made to a person having
`ordinary skill in the art to which [the] subject matter pertains.
`
`20.
`
`I understand that a claimed invention would have been obvious, and
`
`therefore not patentable, if the subject matter claimed would have been considered
`
`obvious to a person of ordinary skill in the art at the time that the invention was
`
`made. I understand that when there are known elements that perform in known
`
`ways and produce predictable results, the combination of those elements is likely
`
`obvious. Further, I understand that when there is a predictable variation and a
`
`person would see the benefit of making that variation, implementing that
`
`predictable variation is likely not patentable. I have also been informed that
`
`obviousness does not require absolute predictability of success, but that what does
`
`matter is whether the prior art gives direction as to what parameters are critical and
`
`which of many possible choices may be successful.
`
`III. PERSON OF ORDINARY SKILL IN THE ART
`21. A person of skill in the art at the time of the alleged invention of the
`
`’455 patent would have had 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.
`
`5
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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`IV. OVERVIEW OF THE ’455 PATENT
`22. The ’455 patent is directed to a laser sustained plasma light source for
`
`use in, for example, testing and inspection for semiconductor manufacturing. As
`
`depicted in Fig. 1, shown below, the light source includes a chamber (green), an
`
`ignition source (blue) for igniting a plasma, and a laser (red) for providing energy
`
`to the plasma to produce light. (’455 patent, 4:25-7:34 (Ex. 1501).)
`
`
`
`’455 patent Fig. 1 (Ex. 1501) (Annotated)
`
`23. The ’455 patent also describes the use of reflectors for reflecting or
`
`transmitting laser light and plasma energy. For example, as illustrated in Figure 5,
`
`below, reflective surface 540 (purple) can direct laser energy to the plasma in the
`
`chamber and direct emitted light towards the output. (’455 patent, 13:10-29 (Ex.
`
`1501).) Additionally, reflector 512 (orange) reflects the laser beam 520 toward the
`
`reflective surface 540 (purple) of the chamber and the reflector 512 (orange) is
`
`substantially transparent to plasma light 536. (’455 patent, 13:10-29 (Ex. 1501).)
`
`6
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`
`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`
`’455 patent Fig. 5 (Ex. 1501) (Annotated)
`
`
`
`24. According to the ’455 patent, prior art light sources relied upon
`
`electrodes to both generate and sustain the plasma, which resulted in wear and
`
`contamination. (’455 patent, 1:28-44 (Ex. 1501).) Thus, a need allegedly arose for
`
`a way to sustain a plasma without relying on an electrical discharge from
`
`electrodes. (’455 patent, 1:45-49 (Ex. 1501).) The purported invention involves
`
`using a laser to provide energy to sustain the plasma to produce a “high brightness”
`
`light source. (See, e.g., ’455 patent, 1:57-59 (Ex. 1501).) Additionally, the
`
`purported invention also involves different configurations of reflectors to direct
`
`laser energy and plasma light. (’455 patent, 4:25-7:34 (Ex. 1501).)
`
`25. As discussed below, sustaining a plasma with a laser to produce high
`
`brightness light and using configurations of reflectors to direct laser energy and
`
`plasma light was well known prior to the earliest claimed priority date of the ’455
`
`patent. Prior art references, such as Gärtner, disclosed a laser-sustained plasma
`
`7
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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`light source with the same elements as the ’455 patent: a chamber, an ignited
`
`plasma, a laser, and reflective surfaces.
`
`26. Furthermore, there was nothing new about using a dichroic mirror to
`
`separate out (a) light from a laser beam, and (b) light emitted from a target
`
`irradiated by the laser. For example, Ito disclosed using a dichroic mirror to
`
`separate out light in this fashion.
`
`A.
`
`Summary of the Prosecution History
`
`27. The ’455 patent issued from U.S. Patent Appl. No. 11/695,348, filed
`
`on April 2, 2007. On May 4, 2010, all the claims were allowed without a rejection
`
`based on prior art. The Notice of Allowability provided several reasons for
`
`allowance, including a statement that the invention involved igniting a gas within a
`
`chamber with a reflective surface and providing laser energy to the ionized gas in
`
`the chamber to produce a plasma that generates high brightness light. (Notice of
`
`Allowability, dated May 10, 2010, at 3-4 (Ex. 1506).) The ’455 patent issued on
`
`August 31, 2010.
`
`28. The independent claim features identified in the Notice of
`
`Allowability as missing from the prior art are present in the prior art used in the
`
`proposed grounds of unpatentability, as the Board recognized in its Decision on
`
`Institution in an IPR directed to the same patent. (Case No. IPR2015-01279, slip
`
`op. at 12 (PTAB Nov. 30, 2015) (Paper 13).).
`
`8
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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`
`V. CLAIM CONSTRUCTION
`29.
`I have applied the “broadest reasonable interpretation” standard in
`
`proposing the claim constructions below. However, based on my reading of the
`
`’455 patent’s specification and the ordinary meanings of the claim terms, the prior
`
`art teaches each claim limitation under any reasonable interpretation of the claim
`
`terms. My analysis is not dependent on application of the “broadest reasonable
`
`interpretation” standard.
`
`A.
` “Light source”
`30. The term “light source” is recited in claim 34. “Light source” should
`
`be construed to mean “a source of 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.”
`
`31. The ordinary and customary meaning of “light source”1 is a source of
`
`electromagnetic radiation in the extreme ultraviolet (10 nm to 100 nm), vacuum
`
`1 The term “light” is sometimes used more narrowly to refer only to visible light.
`
`However, references to “ultraviolet light” in the ’455 patent make clear that the
`
`broader meaning is intended because ultraviolet light has a wavelength shorter than
`
`that of visible light. (See, e.g., ʼ455 patent, 7:33-34; 8:44-45; 10:19-20; 10:48-50;
`
`12:3-5; 12:11-13; 12:44-46; 13:64-14:4; 14:55-57; 17:3-4 (Ex. 1501).)
`
`9
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`

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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`ultraviolet (100 nm to 200 nm), ultraviolet (200 nm to 400 nm), visible (400 to 700
`
`nm), near-infrared (700 nm to 1,000 nm (1 µm)), middle infrared (1 µm to 10 µm),
`
`or far infrared (10 µm to 1,000 µm) regions of the spectrum. (See, e.g., William T.
`
`Silfvast, “Laser Fundamentals,” at 4 (2d ed. 2003) (“Silfvast”) (Ex.1510).) The
`
`Patent Owner publishes a data sheet which is consistent with the ordinary and
`
`customary meaning, in considering EUV [Extreme Ultraviolet] to be within the
`
`meaning of “light source.” (See, e.g., EQ-10M Data Sheet (describing Energetiq’s
`
`EQ-10 product operating at 13.5 nm as an “EUV Light Source”) (Ex. 1511).)
`
`32. The ’455 patent does not provide a definition of the term “light
`
`source” and uses the term consistent with the ordinary and customary meaning of
`
`the term. The ’455 patent states that parameters such as the wavelength of the light
`
`from a light source vary depending upon the application. (’455 patent, 1:25-27
`
`(Ex. 1501).) The specification describes “ultraviolet light” as an example of the
`
`type of light that can be generated: “In some embodiments, the high brightness
`
`light 636 includes ultraviolet light.” (’455 patent, 13:67-14:1, (Ex. 1501); see also
`
`id. at 17:1-4 (discussing the ultraviolet light 836 generated by the plasma 832 of
`
`the light source).)
`
`33. Therefore, the term “light source” should be construed to mean “a
`
`source of electromagnetic radiation in the ultraviolet (“UV”), extreme UV, vacuum
`
`10
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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`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.”2
`
`B.
` “High brightness light”
`34. Challenged claims 28, 31, and 33-34 recite the term “high brightness
`
`light.” For purposes of this proceeding, the term “high brightness light”3 should be
`
`construed to include “light sufficiently bright to be useful for: inspection, testing or
`
`measuring properties associated with semiconductor wafers or materials used in
`
`the fabrication of wafers, or as a source of illumination in a lithography system
`
`
`2 The particular construction for the claim term “light source” was adopted by the
`
`Board in the Decision granting Institution of Inter Partes Review for claims 19 and
`
`39-41. (See Case No. IPR2015-01279 (PTAB Nov. 30, 2015) (Paper 13).) This
`
`construction is equivalent to the Petitioner’s prior proposed construction for the
`
`term “light source” in the prior Petitions for the ’455 patent and other patents in the
`
`patent family.
`
`3 The ’455 patent does not specify how bright the light must be. However, for
`
`purposes of this proceeding, it is sufficient to interpret “high brightness light” as
`
`explained above, and each prior art reference used in the grounds of unpatentability
`
`is directed to providing light with sufficient brightness for purposes identified in
`
`the challenged patent.
`
`11
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`
`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`used in the fabrication of wafers, microscopy system, photoresist curing systems,
`
`or endoscopic tools.”
`
`35. The ’455 patent defines “brightness”4 as “the power radiated by a
`
`source of light per unit surface area into a unit solid angle.” (’455 patent, 8:27-28
`
`(Ex. 1501).) The brightness of the light produced by a light source “determines”
`
`the ability of a system or operator to “see or measure things … with adequate
`
`resolution.” (’455 patent, 8:28-32 (Ex. 1501).)
`
`36. The ’455 patent recognizes that high brightness light has been used
`
`for various purposes long before the ’455 patent was filed. The patent recognizes
`
`in the Background of the Invention that, “[f]or example, a high brightness light
`
`source can be used for inspection, testing or measuring properties associated with
`
`semiconductor wafers or materials used in the fabrication of wafers (e.g., reticles
`
`and photomasks).” (’455 patent, 1:17-21 (Ex. 1501).) It also identifies light
`
`sources that can be used “as a source of illumination in a lithography system used
`
`in the fabrication of wafers, a microscopy system[], or a photoresist curing system”
`
`as further examples of high brightness light sources. (’455 patent, 1:21-25 (Ex.
`
`1501).) Additionally, it describes and claims “a wafer inspection tool, a
`
`4 Although the ’455 patent uses the term “brightness,” “spectral brightness” is the
`
`more common term in optics and lasers. “Spectral brightness” refers to the optical
`
`power radiated per unit of wavelength (nm) per steradian, the unit of solid angle.
`
`12
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`

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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`microscope, a metrology tool, a lithography tool, [and] an endoscopic tool” as tools
`
`for which the high brightness light is produced. (’455 patent, 2:46-50, 3:61-64,
`
`10:15-21, 15:8-14 (Ex. 1501).) More generally, the patent acknowledges that the
`
`brightness and other parameters of the light “vary depending upon the application.”
`
`(’455 patent, 1:25-27 (Ex. 1501).)
`
`37. The Patent Owner has argued that the term “high brightness light”
`
`should be understood as “bright enough to be used for inspection, testing, or
`
`measuring properties associated with semiconductor wafers or materials used in
`
`the fabrication of wafers, or in lithography systems used in the fabrication of
`
`wafers, microscopy systems, or photoresist curing systems—i.e., at least as bright
`
`as xenon or mercury arc lamps,” which is similar to the construction proposed
`
`below but omits applications specifically identified in the ’455 patent. (See Second
`
`Smith Declaration ¶ 20 (Ex. 1508).)
`
`38. Therefore, for purposes of this proceeding, the term “high brightness
`
`light” should be interpreted to include “light sufficiently bright to be useful for:
`
`inspection, testing or measuring properties associated with semiconductor wafers
`
`or materials used in the fabrication of wafers, or as a source of illumination in a
`
`13
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`

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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`lithography system used in the fabrication of wafers, microscopy systems,
`
`photoresist curing systems, or endoscopic tools.” 5
`
`C.
`
`“Means for providing electromagnetic energy to the ionized gas
`within the chamber to produce a plasma that generates a high
`brightness light.”
`39. Challenged claim 34 recites “a means for providing electromagnetic
`
`energy to the ionized gas within the chamber to produce a plasma that generates a
`
`high brightness light.”
`
`(a) Function
`
`40. The function is “providing electromagnetic energy to the ionized gas
`
`within the chamber to produce a plasma that generates a high brightness light.”
`
`(b) Structure
`
`41. The corresponding structure for performing the function includes a
`
`laser source. The ’455 patent states:
`
`The laser source can be, for example, an infrared (IR) laser source, a
`diode laser source, a fiber laser source, an ytterbium laser source, a
`CO2 laser source, a YAG laser source, or a gas discharge laser source.
`In some embodiments, the laser source 104 is a pulse laser source
`(e.g., a high pulse rate laser source) or a continuous wave laser source.
`
`
`5 The proposed construction for the claim term “high brightness light” was adopted
`
`by the Board in the Decision granting Institution of Inter Partes Review for claims
`
`19 and 39-41. (See Case No. IPR2015-01279 (PTAB Nov. 30, 2015) (Paper 13).)
`
`14
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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`Fiber lasers use laser diodes to pump a special doped fiber which then
`lases to produce the output (i.e., a laser beam). In some embodiments,
`multiple lasers (e.g., diode lasers) are coupled to one or more fiber
`optic elements (e.g., the fiber optic element 108). Diode lasers take
`light from one, or usually many, diodes and directs the light down a
`fiber to the output. In some embodiments, fiber laser sources and
`direct semiconductor laser sources are desirable for use as the laser
`source 104. …
`(’455 patent, 9:25-39 (Ex. 1501).)
`
`VI. THE CHALLENGED CLAIMS ARE INVALID
`A. Laser Sustained Plasma Light Sources Were Known Long Before
`the Priority Date of the ’455 Patent
`42. When the application that led to the ’455 patent was filed, there was
`
`nothing new about using an ignition source to generate a plasma in a chamber, a
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`laser to sustain the plasma to produce high brightness light from the plasma, and
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`reflective surfaces as described and claimed in the ’455 patent. This concept had
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`been known and widely used since at least as early as the 1980s, more than two
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`decades before the application date. For example, in 1983, Gärtner et al. filed a
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`patent application entitled “Radiation source for optical devices, notably for
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`photolithographic reproduction systems,” which published on May 3, 1985 as
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`French Patent Application No. 2554302. (“Gärtner,” Ex. 1504.) As shown in Fig.
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`1, reproduced below adjacent to Fig. 1 of the ’455 patent, Gärtner disclosed a light
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`source with the same features claimed in the ’455 patent: (1) a chamber 1 (green);
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`15
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`

`
`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`(2) an ignition source – pulsed laser 10 (blue), which ionizes a gas; (3) a laser to
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`produce plasma light – laser 9 (red), which provides energy to the plasma 14 and
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`produces light 15; and (4) a reflective surface 12 (purple). (Gärtner, 4:31-5:9 (Ex.
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`1504).)
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`’455 patent Fig. 1 (Ex. 1501) (Annotated)
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`Gärtner, Fig. 1 (Ex. 1504)
`
`
`
`(Annotated)
`
`43.
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`In addition, on August 31, 2005, Ershov et al. filed U.S. Patent
`
`Application No. 2006/0192152, entitled “LPP EUV Light Source Drive Laser
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`System.” (“Ershov,” Ex. 1516). As shown in Figs. 1 and 12, reproduced below,
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`Ershov discloses a light source with features similar to the ’455 patent: (1) a
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`chamber (represented below in green); (2) an ignited plasma at focal point 28
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`(blue); (3) a laser for providing energy to the plasma – laser light 342 (red); and (4)
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`16
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`

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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`reflective surface 30 for reflecting laser light and plasma energy (purple). (See
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`Ershov, ¶¶ 22-23, Fig. 1 (Ex. 1516).)
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`
`
`
`
`Ershov, Fig. 1 (Ex. 1516) (Annotated)
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`Ershov, Fig. 12 (Ex. 1516) (Annotated)
`
`17
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`

`
`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`B. Using a dichroic mirror to separate light of different wavelengths
`was well known in the art.
`44. Dichroic mirrors are standard optical elements that have been part of
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`the skilled person’s toolkit for building optical systems for decades. (See, e.g.,
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`IEEE Standard Dictionary of Electrical and Electronic Terms (1988) (“Dichroic
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`mirror (fiber optics). A mirror designed to reflect light selectively according to
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`wavelength.”) (Ex. 1513).) Dichroic mirrors generally use the known principle of
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`thin film interference, which uses alternating layers of optical coatings with
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`different refractive indexes built upon a transparent substrate, such as glass or
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`quartz. (See, e.g., James Ingle and Stanley Crouch, “Spectrochemical Analysis,” at
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`59 Prentice Hall (1998) (“Another type of beam splitter is a wavelength-selective
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`beam splitter or dichroic mirror. Such mirrors are made from multilayer,
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`nonabsorbing films.”) (Ex. 1515).) One of skill in the art would have known that
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`by controlling the thickness and the number of layers, the frequency (wavelength)
`
`of the passband of the filter can be tuned and made as wide or narrow as desired.
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`45. Furthermore, one of skill in the art would have understood how to use
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`a dichroic mirror that selectively reflects at least one wavelength of light in order
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`to separate out (i) light from a laser beam from (ii) light emitted by a target
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`irradiated by the laser beam. For example Ito describes using a dichroic mirror that
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`reflects a laser beam having a fundamental frequency of 1064 nm onto a target,
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`which causes the target to generate light. (Ito at 3 (Ex. 1505).) The light generated
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`18
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`

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`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`from the target is then passed back to the dichroic mirror. Since the dichroic
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`mirror in this example only reflects light with wavelengths around 1064 nm, the
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`generated light passes through the dichroic mirror without being reflected back
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`toward the laser. (Id.)
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`46. Thus, the purportedly novel features of the ’455 patent are, in
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`actuality, standard features of laser sustained plasma light sources described in
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`prior art from the 1980s onward.
`
`VII. GROUNDS FOR FINDING THE CHALLENGED CLAIMS INVALID
`47. Pursuant to Rule 42.104(b)(4)-(5), specific grounds for finding the
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`challenged claims invalid are identified below. These grounds demonstrate in
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`detail that claims 28-34 are invalid under 35 U.S.C. §§ 102 and 103.
`
`A. Ground 1: Claim 28 is unpatentable over Gärtner
`48. Claim 28 relates to a method for producing light by ionizing a gas
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`within a chamber comprising a reflective surface and by producing a plasma that
`
`generates a high brightness light. Claim 28 is anticipated by Gärtner, as outlined in
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`the chart below.
`
`
`
`’455 Patent Claim 28
`
`Prior Art
`
` [28p] 28. A method for producing light,
`comprising:
`
` [28a] ionizing with an ignition source a gas
`within a chamber comprising a reflective surface;
`and
`
`Gärtner, 1:1-4, 3:1-4, Figs.
`1-4
`
`Gärtner, 3:20, 4:32, 5:15-16,
`6:9-10, Fig. 1
`
`19
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`

`
`U.S. Patent 7,786,455
`Declaration of Howard Milchberg, Ph.D.
`
`
`
`’455 Patent Claim 28
`
`Prior Art
`
` [28b] directing electromagnetic energy from a
`laser toward a reflector that at least substantially
`reflects a first set of wavelengths of
`electromagnetic energy toward the ionized gas in
`the chamber to produce a plasma that generates a
`high brightness light.
`
`Gärtner, 1:22, 3:20, 4:31-
`5:9, 5:15-16, 5:28-31, 6:9-
`16, Figs. 1-4
`
`
`(a) Gärtner was not considered by the Patent Office during
`examination
`
`49.
`
`I have been informed that Gärtner is prior art under 35 U.S.C. §
`
`102(b) because it published more than a year before the earliest claimed priority
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`date for the ’455 patent, which is March 31, 2006. Gärtner was not considered by
`
`the Examiner during prosecution of the ’455 patent.
`
`(b) Claim 28 is anticipated by Gärtner
`
`50. Claim 28 of the ’455 patent is anticipated by Gärtner.
`
`a)
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`Claim 28 - Preamble (element [28p])
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`51. The Preamble of claim 28 recites “A method for producing light.”
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`(’455 patent, 19:36 (Ex. 1501).) Gärtner disc