DOCKET NO.: 0107945.00235US10
`Filed By: Donald R. Steinberg, Reg. No. 37,241
`David L. Cavanaugh, Reg. No. 36,476
`Michael H. Smith, Reg. No. 71,190
`60 State Street
`Boston, Massachusetts 02109
`Tel: (617) 526-6000
`Email: Don.Steinberg@wilmerhale.com
`
` David.Cavanaugh@wilmerhale.com
`
` MichaelH.Smith@wilmerhale.com
`
`
`
`
`
`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 IPR2016-00127
`
`
`
`PETITION FOR INTER PARTES REVIEW OF
`U.S. PATENT NO. 8,969,841
`CLAIMS 10, 13, and 14
`
`
`
`
`
`

`
`TABLE OF CONTENTS
`
`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`
`
`Page
`
`I.
`
`MANDATORY NOTICES ............................................................................. 1
`A.
`Real Parties-in-Interest .......................................................................... 1
`B.
`Related Matters ...................................................................................... 1
`C.
`Counsel .................................................................................................. 1
`D.
`Service Information ............................................................................... 2
`CERTIFICATION OF GROUNDS FOR STANDING .................................. 2
`II.
`III. OVERVIEW OF CHALLENGE AND RELIEF REQUESTED .................... 2
`A. Grounds for Challenge .......................................................................... 2
`B.
`Prior Art Patents and Printed Publications Relied Upon ...................... 2
`C.
`Relief Requested .................................................................................... 3
`IV. PERSON OF ORDINARY SKILL IN THE ART .......................................... 3
`V. OVERVIEW OF THE ’841 PATENT ............................................................ 3
`A.
`Challenged Claims ................................................................................ 5
`B.
`Summary of the Prosecution History .................................................... 6
`VI. CLAIM CONSTRUCTION ............................................................................ 9
`A.
`“Light source” ..................................................................................... 10
`B.
`“Laser Driven Light Source” ............................................................... 12
`C.
`“Light Bulb” ........................................................................................ 13
`VII. THE CHALLENGED CLAIMS ARE UNPATENTABLE .......................... 14
`A.
`Laser Sustained Plasma Light Sources Were Known Long
`Before the Priority Date of the ’841 Patent ......................................... 14
`Sustaining a plasma with a laser at various wavelengths,
`including those up to about 2000 nm, was well known in the art ....... 16
`VIII. GROUNDS FOR FINDING THE CHALLENGED CLAIMS INVALID ... 22
`A. Ground 1: Claims 10, 13, and 14 Are Unpatentable Over
`Gärtner in View of Mourou ................................................................. 22
`1.
`Independent Claim 10 .................................................................. 23
`2. Dependent Claims ........................................................................ 42
`
`B.
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`i
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`

`
`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`
`
`B.
`
`Ground 2: Claims 10, 13, and 14 Are Unpatentable Over
`Gärtner in View of Kensuke ................................................................ 44
`1.
`Independent Claim 10 .................................................................. 46
`2. Dependent Claims ........................................................................ 56
`IX. RESPONSE TO ARGUMENTS RAISED BY PATENT OWNER IN ITS
`PRELIMINARY INJUNCTION MOTION .................................................. 57
`A.
`Patent Owner’s Arguments Regarding Objective Indicia of
`Non-Obviousness ................................................................................ 58
`CONCLUSION .............................................................................................. 59
`
`X.
`
`
`ii
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`

`
`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`
`I. MANDATORY NOTICES
`A. Real Parties-in-Interest
`ASML Netherlands B.V., Excelitas Technologies Corp., and Qioptiq
`
`Photonics GmbH & Co. KG (“Petitioners”) are the real parties-in-interest.
`
`B. Related Matters
`U.S. Patent No. 8,969,841 (“the ’841 patent,” Ex. 1101) is one member of a
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`patent family of continuation and continuation in part applications. Exhibit 1102
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`shows the members of this patent family and the relationships among them.
`
`Petitioners filed a separate petition seeking inter partes review of claims 1-3 and 7
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`of the ’841 patent, and are also seeking inter partes review of related U.S. Patent
`
`Nos. 7,435,982 (“the ’982 patent”); 7,786,455 (“the ’455 patent”); 8,309,943 (“the
`
`’943 patent”); 8,525,138 (“the ’138 patent”); and 9,048,000 (“the ’000 patent”).
`
`Petitioners request that the inter partes reviews of the ’841, ’982, ’455, ’943,’138,
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`and ’000 patents be assigned to the same Panel for administrative efficiency.
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`The following litigation matter would affect or be affected by a decision in
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`this proceeding: Energetiq Tech., Inc. v. ASML Netherlands B.V., No. 1:15-cv-
`
`10240-LTS (D. Mass.).
`
`C. Counsel
`Lead Counsel: Donald R. Steinberg (Registration No. 37,241)
`
`Backup Counsel: David L. Cavanaugh (Registration No. 36,476)
`
`Second Backup Counsel: Michael H. Smith (Registration No. 71,190)
`
`1
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`

`
`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`
`Service Information
`
`D.
`Email: Donald R. Steinberg, don.steinberg@wilmerhale.com
`
`Post and Hand Delivery: WilmerHale, 60 State St., Boston MA 02109
`
`Telephone: 617-526-6453
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`
`
`Facsimile: 617-526-5000
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`II. CERTIFICATION OF GROUNDS FOR STANDING
`Petitioners certify pursuant to Rule 42.104(a) that the patent for which
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`review is sought is available for inter partes review and that Petitioners are not
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`barred or estopped from requesting an inter partes review challenging the patent
`
`claims on the grounds identified in this Petition.
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`III. OVERVIEW OF CHALLENGE AND RELIEF REQUESTED
`Pursuant to Rules 42.22(a)(1) and 42.104 (b)(1)-(2), Petitioners challenge
`
`claims 10, 13 and 14 of the ’841 patent (“the challenged claims”) and request that
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`each challenged claim be cancelled.
`
`A. Grounds for Challenge
`This Petition, supported by the declaration of Dr. J. Gary Eden, a Professor
`
`of Electrical Engineering at the University of Illinois (“Eden Decl.,” Ex. 1103),
`
`demonstrates that there is a reasonable likelihood that Petitioners will prevail with
`
`respect to at least one of the challenged claims and that each of the challenged
`
`claims is unpatentable for the reasons cited in this petition. 35 U.S.C. § 314(a).
`
`Prior Art Patents and Printed Publications Relied Upon
`
`B.
`Petitioners rely upon the following patents and printed publications:
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`2
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`

`
`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`1. French Patent Publication No. FR2554302A1, published May 3, 1985
`
`(“Gärtner,” Ex. 1104), with English Translation, and is prior art to the ʼ841
`
`patent under 35 U.S.C. § 102(a) and 102(b).
`
`2. International Publication WO-2004097520, published November 11, 2004
`
`(“Mourou,” Ex. 1114), and is prior art to the ʼ841 patent under 35 U.S.C. §
`
`102(a) and 102(b).
`
`3. Japanese Patent Publication No. 2006010675A, published January 12, 2006
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`(“Kensuke,” Ex. 1105), with English Translation, and is prior art to the ʼ841
`
`patent under 35 U.S.C. § 102(a) and 102(b).
`
`C. Relief Requested
`Petitioners request that the Patent Trial and Appeal Board cancel the
`
`challenged claims because they are unpatentable under 35 U.S.C. § 103.
`
`IV. PERSON OF ORDINARY SKILL IN THE ART
`A person of skill in the art at the time of the alleged invention of the ’841
`
`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
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`experience with lasers and plasma. (Eden Decl. ¶ 24 (Ex. 1103).)
`
`V. OVERVIEW OF THE ’841 PATENT
`The ’841 patent family is directed to a laser sustained plasma light source for
`
`3
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`

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`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`use in, for example, testing and inspection for semiconductor manufacturing. As
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`depicted in Fig. 1 below, the light source includes a sealed pressurized chamber
`
`containing gas (green), an ignition source for ionizing the gas (blue), a laser
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`providing energy to the plasma (red), light-generating plasma, and the chamber
`
`having a transparent region to allow the plasma-generated light to exit. (’841
`
`patent, claim 10 (Ex. 1101).) (Eden Decl. ¶ 25 (Ex. 1103).)
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`ʼ841 Patent, Figure 1 (Ex. 1101)
`
`
`
`According to the ’841 patent, prior art light sources relied upon electrodes to
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`both generate and sustain the plasma, which resulted in wear and contamination.
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`(’841 patent, 1:42-58 (Ex. 1101).) Thus, a need arose for a way to sustain plasma
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`without relying on an electrical discharge from electrodes. (’841 patent, 1:59-63
`
`(Ex. 1101).) (Eden Decl. ¶ 26 (Ex. 1103).)
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`4
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`

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`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`The alleged invention of the patent family involves using a laser to sustain
`
`the plasma for a light source. The ’841 continuation adds claims that require that
`
`the laser operate at a wavelength of up to 2000 nm. (Eden Decl. ¶ 27 (Ex. 1103).)
`
`As discussed below, there was nothing new in 2006 about sustaining a
`
`plasma with a laser to produce high brightness light. Multiple prior art references,
`
`including Gärtner, Mourou, and Kensuke, disclosed laser-sustained plasma light
`
`sources with pressurized chambers, lasers operating within certain wavelength
`
`ranges, and emitting light at certain wavelengths. Moreover, there was nothing
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`new about providing energy to a plasma with a laser operating at a wavelength of
`
`up to 2000 nm. As the patent admits, several such lasers (and high power fiber
`
`lasers, in particular) had recently become more widely available and incorporating
`
`any of these lasers into laser-generated and sustained plasma light sources was
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`straightforward. Mourou and Kensuke provide two examples of systems that
`
`provide energy to a plasma with a laser operating at a wavelength of up to 2000
`
`nm. It would have been obvious to combine Mourou and Kensuke’s teachings
`
`with Gärtner to arrive at the claimed invention. (Eden Decl. ¶ 28 (Ex. 1103).)
`
`A. Challenged Claims
`
`Petitioner challenges claims 10, 13, and 14 of the ’841 patent. Independent
`
`claim 10 is reproduced below with added letters and numerals in brackets for ease
`
`of reference:
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`5
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`

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`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`[10p] A laser driven light source, comprising:
`[10a] a light bulb defining a sealed pressurized chamber containing a
`gas at an operating pressure of greater than 10 atmospheres;
`[10b] an ignition source for ionizing a gas within the light bulb,
`[10c] at least one at least substantially continuous laser for providing
`energy within a wavelength range of up to about 2000 nm to the
`ionized gas to sustain a plasma within the light bulb to produce a
`plasma-generated light having output wavelengths greater than 50 nm,
`[10d] the sealed pressurized chamber further comprising a region of
`material which is transparent to at least a portion of the plasma-
`generated light, the region of material allowing said portion of the
`plasma-generated light to exit the light bulb and illuminate a surface.
`
`(’841 patent, claim 10 (Ex. 1101).)
`
`B.
`
`Summary of the Prosecution History
`
`The ’841 patent (Ex. 1101) issued from U.S. Patent Appl. No. 14/510,959,
`
`filed on October 9, 2014. The ’841 patent application is a continuation of the ’000
`
`patent, which is a continuation of the ’138 patent, which is a continuation in part of
`
`the ’786 patent, which is a continuation in part of the ’455 patent, which is a
`
`continuation in part of the ’982 patent, filed March 31, 2006. (See Chart of
`
`Related Patents (Ex. 1102).) As explained below, the Examiner allowed the claims
`
`of the ʼ841 patent only after the applicant amended the claims to include a
`
`limitation regarding the laser wavelength.
`
`On November 12, 2014, the Examiner rejected the claims in light of various
`
`6
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`

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`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`prior art references. (Office Action dated Nov. 12, 2014 (Ex. 1108).) The claims
`
`were primarily rejected based on U.S. 4,780,608 (“Cross”) and U.S. 6,541,924
`
`(“Kane”). The Office Action asserted that “Cross discloses a light source
`
`comprising a pressurized chamber in which a laser sustained plasma emits [] light,”
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`and that Kane discloses a ultraviolet light source comprising a pressurized chamber
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`and an electrode ignition source. (Id. at 2-4.)
`
`On December 17, 2014, the applicant responded by amending the claims to
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`include features such as a “sealed” chamber, a pressure above 10 atm, wavelength
`
`ranges for the laser and the light produced by the plasma, and a chamber that has a
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`transparent region. (Applicant’s Amendment and Response dated Dec. 17, 2014 at
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`3 (Ex. 1109).) For example, pending claim 15 (now claim 10) was amended as
`
`shown below (id. at 4-5):
`
`
`
`
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`7
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`

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`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`
`
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`The applicant also added dependent claims further specifying the pressure
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`and properties of the laser and plasma. The applicant argued that the claims, as
`
`amended to include the additional limitations, were distinct from the prior art
`
`because allegedly “none of the references of record produce a plasma generated
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`light having output wavelengths greater than 50 nm.”1 (Id. at 11.)
`
`On January 22, 2015, the newly amended claims were allowed. (Notice of
`
`Allowability dated Jan. 22, 2015 at 2 (Ex. 1110).) With respect to pending claims
`
`1, 15 (now claim 10), and 20, the Examiner introduced Manning U.S. PGPUB No.
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`2006/0152128 (“Manning”) but noted that Manning did not disclose the use of a
`
`laser with a wavelength in the 700-2000 nm interval to create a plasma that
`
`produced electromagnetic radiation with a wavelength greater than 50 nm. (Id.)
`
`Regarding Cross, the Examiner stated that in addition to not disclosing a laser with
`
`a wavelength from 700-2000 nm, the reference did not disclose a transparent
`
`
`1 Patent Owner was in fact mistaken. For example, Kane discloses a “plasma
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`lamp” that is “capable of providing a source of high-peak-power incoherent
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`ultraviolet (UV) light (80-350 nm, more typically 11-320 nm).” (U.S. Patent No.
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`6,541,924 (“Kane”) at 7:53-59 (Ex. 1118).) (Eden Decl. ¶ 33 n. 1 (Ex. 1103).)
`
`8
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`

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`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`region of the chamber and was concerned with producing ions instead of light
`
`produced by a plasma. (Id. at 2-3.) The Examiner also stated that it would not
`
`have been obvious to combine Manning and Cross because “they belong to
`
`different fields of endeavor; namely, Manning uses a plasma to generate light,
`
`while Cross uses a plasma to generate ions.” (Id. at 3.)
`
`The Examiner, however, did not consider Gärtner or Mourou, nor was the
`
`Examiner provided a complete English translation of Kensuke.2 As discussed
`
`below, Gärtner in view of Mourou and Gärtner in view of Kensuke each render the
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`challenged claims unpatentable as obvious in view of the combinations below.
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`VI. CLAIM CONSTRUCTION
`Claims in inter partes review are given the “broadest reasonable
`
`construction in light of the specification of the patent in which [they] appear[].” 37
`
`C.F.R. § 42.100(b); see Office Patent Trial Practice Guide, 77 Fed. Reg. 48,756,
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`2 Kensuke (JP 2006-10675) was included in an Information Disclosure Statement
`
`filed by applicant on October 9, 2014. However, applicant only submitted an
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`English translation for the abstract and Kensuke was not used in any of the
`
`Examiner’s rejections. Notably, as described further below, Kensuke discloses the
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`use of a laser with a wavelength of less than 2000 nm to create a plasma that
`
`produces a light with a wavelength greater than 50 nm, but the abstract does not
`
`provide this disclosure. (See infra at section VIII.B.1.d).)
`
`9
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`

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`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`48, 764, 48,766 (Aug. 14, 2012). Claim terms are given their ordinary and
`
`customary meaning as would be understood by a person of ordinary skill in the art
`
`at the time of the invention and in the context of the entire patent disclosure. In re
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`Translogic Tech., Inc., 504 F.3d 1249, 1257 (Fed. Cir. 2007). If the specification
`
`sets forth an alternate definition of a term with “reasonable clarity, deliberateness,
`
`and precision[,]” the patentee’s lexicography governs. In re Paulsen, 30 F.3d
`
`1475, 1480 (Fed. Cir. 1994).
`
`Should the Patent Owner, seeking to avoid the prior art, contend that the
`
`claims have a construction different from their broadest reasonable construction,
`
`the appropriate course is for the Patent Owner to seek to amend the claims to
`
`expressly correspond to its contentions in this proceeding. See 77 Fed. Reg. at
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`48,766-67.
`
`Consistent with this standard, this section proposes, under the broadest
`
`reasonable construction standard, constructions of terms and provides support for
`
`these proposed constructions. Terms not included in this section have their
`
`broadest reasonable meaning in light of the specification as commonly understood
`
`by those of ordinary skill.
`
`“Light source”
`
`A.
` The term “light source” is recited in challenged claims 10, 13, and 14.
`
`“Light source” should be construed to mean “a source of electromagnetic radiation
`
`10
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`

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`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`in the extreme ultraviolet (10 nm to 100 nm), vacuum 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 (1µm)), middle infrared (1 µm to 10 µm), or far infrared (10 µm to
`
`1,000 µm) regions of the spectrum.” (Eden Decl. ¶ 36 (Ex. 1103).)
`
`The ordinary and customary meaning of “light source”3 is a source of
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`electromagnetic radiation in the extreme ultraviolet (10 nm to 100 nm), vacuum
`
`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 (1µm)), 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., 2004) (Ex. 1106).) The Patent Owner
`
`publishes a data sheet which is consistent with the ordinary and customary
`
`meaning in recognizing that “light source” includes EUV wavelengths. (See, e.g.,
`
`Energetiq EQ-10M Data Sheet at 2 (describing Energetiq’s EQ-10M product
`
`operating at 13.5 nm as an “EUV [Extreme Ultraviolet] Light Source”) (Ex.
`
`1107).) (Eden Decl. ¶ 37 (Ex. 1103).)
`
`3 The term “light” is sometimes used more narrowly to refer only to visible light.
`
`However, references to “ultraviolet light” in the ’841 patent make clear that the
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`broader meaning is intended because ultraviolet light has a wavelength shorter than
`
`that of visible light. (See, e.g., ’841 patent, 7:52; 17:13; 18:43; 20:32-33; 23:29;
`
`26:33) (Ex. 1101).) (See Eden Decl. ¶ 37 n. 3 (Ex. 1103).)
`
`11
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`

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`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`The ’841 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.
`
`Consistent with the ordinary and customary meaning of “light source,” the ’841
`
`patent states that parameters such as the wavelength of the light from a light source
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`“vary depending upon the application.” (’841 patent, 1:39-41 (Ex. 1101).) The
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`specification describes “ultraviolet light” as an example of the type of light that can
`
`be generated: “emitted light 136 (e.g., at least one or more wavelengths of
`
`ultraviolet light).” (’841 patent, 18:34-36 (Ex. 1101); see also id. at 17:12-14
`
`(discussing the ultraviolet light 136 generated by the plasma 132 of the light source
`
`100).) (Eden Decl. ¶ 38 (Ex. 1103).)
`
`Therefore, the term “light source” should be construed to mean “a source of
`
`electromagnetic radiation in the extreme ultraviolet (10 nm to 100 nm), vacuum
`
`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 (1µm)), middle infrared (1 µm to 10 µm),
`
`or far infrared (10 µm to 1,000 µm) regions of the spectrum.” (Eden Decl. ¶ 39
`
`(Ex. 1103).)
`
`“Laser Driven Light Source”
`
`B.
`The term “laser driven light source” should be construed to mean a “light
`
`source having a laser supplying energy to generate light.” (Eden Decl. ¶ 40 (Ex.
`
`1103).)
`
`12
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`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`The term “laser driven light source” is not a term of art. (Eden Decl. ¶ 41
`
`(Ex. 1103).) As used in the ’841 patent, a person of skill in the art would have
`
`understood the term “laser driven light source” to refer to light sources where a
`
`laser supplies energy to generate light. (E.g., ’841 patent, 14:45-50, 63-65 (“The
`
`light source 100 also includes at least one laser source 104 that generates a laser
`
`beam that is provided to the plasma 132 located in the chamber 128 to initiate
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`and/or sustain the high brightness light 136. . . . It is also desirable for the laser
`
`source 104 to drive and/or sustain the plasma with a high power laser beam.”) (Ex.
`
`1101).) (Eden Decl. ¶ 41 (Ex. 1103).)
`
`Therefore, the term “laser driven light source” should be construed to mean
`
`a “light source having a laser supplying energy to generate light.” (Eden Decl. ¶
`
`41 (Ex. 1103).)
`
`“Light Bulb”
`
`C.
`The term “light bulb” should be construed to mean “a light emitting portion
`
`of a light source.” This construction is consistent with the use of the term “bulb”
`
`in the specification (the term “light bulb” appears only in the claims) and with the
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`limitations in claim 10 that relate to the “light bulb.” (E.g., ’841 patent, 20:43-54,
`
`26:52-64, 39:62-64, 49:22-25, 49:31-35 (Ex. 1101).) In the context of the ’841
`
`patent, a person of skill in the art would have understood the term “light bulb” to
`
`mean “a light emitting portion of a light source.” Therefore, the term “light bulb”
`
`13
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`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`should be construed to mean “a light emitting portion of a light source.” (Eden
`
`Decl. ¶ 42 (Ex. 1103).)
`
`VII. THE CHALLENGED CLAIMS ARE UNPATENTABLE
`The challenged claims recite and claim features that were known in the art
`
`prior to the earliest priority date, and are obvious in view of the prior art.
`
`A. Laser Sustained Plasma Light Sources Were Known Long Before
`the Priority Date of the ’841 Patent
`
`When the application that led to the ’841 patent was filed, there was nothing
`
`new or inventive about a light source using an ignition source to generate a plasma
`
`in a pressurized chamber and a laser operating at certain wavelengths to sustain the
`
`plasma to produce high brightness light at certain wavelengths. This concept had
`
`been known and widely used since at least as early as the 1980s, more than two
`
`decades before the application date. For example, in 1983, Gärtner filed a patent
`
`application entitled “Radiation source for optical devices, notably for
`
`photolithographic reproduction systems,” which published on May 3, 1985 as
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`French Patent Application No. 2554302. (Gärtner, Ex. 1104). Gärtner describes a
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`light source for optical systems: “The present invention relates to a radiation
`
`source for optical devices, in particular for photolithographic reproduction
`
`systems.” (Gärtner at 1 (Ex. 1104).) (Eden Decl. ¶ 44 (Ex. 1103).)
`
`Gärtner is directed to the same application as that addressed by the ’841
`
`patent, namely, producing light that is brighter than that produced by conventional
`
`14
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`U.S. Patent 8,969,841
`Petition for Inter Partes Review
`arc lamps for applications such as photolithography. (Compare Gärtner at 1:2-4
`
`(“It is preferably applied in cases where a radiated power is required which is
`
`greater than that from pressurised mercury vapour lamps, such as in
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`photolithographic appliances for illuminating a photoresist layer on a
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`semiconductor wafer.”) (Ex. 1104) with ’841 patent, 1:42-63 (“[A]rc lamps do not
`
`provide sufficient brightness for some applications, especially in the ultraviolet
`
`spectrum. . . . Accordingly, a need therefore exists for improved high brightness
`
`light sources.”) (Ex. 1101).) (Eden Decl. ¶ 45 (Ex. 1103).)
`
`Gärtner proposes the same basic solution as the ’841 patent, albeit more than
`
`twenty years earlier: (1) a sealed chamber, (2) an ignition source, and (3) a laser
`
`that sustains a plasma providing high-brightness light. (Compare Gärtner at 4:31-
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`35, 5:1-9, Fig. 1 (Ex. 1104) with ’841 patent, 2:8-15, Fig. 1 (Ex. 1101).) For
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`example, Figure 1 of Gärtner below depicts a “gas-tight chamber 1” (green); “laser
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`10” (blue) as an ignition source for generating the plasma 14; and a “laser 9” (red)
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`for sustaining the plasma (yellow) and producing a high brightness light. (Gärtner
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`at 4-5, Fig. 1 (Ex. 1104).) (Eden Decl. ¶ 46 (Ex. 1103).)
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`’841 patent, Fig. 1 (Ex. 1101)
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`Gärtner, Fig. 1 (Ex. 1104)
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`B.
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`Sustaining a plasma with a laser at various wavelengths, including
`those up to about 2000 nm, was well known in the art
`Gärtner’s laser 9 is a CO2 laser. (Gärtner at 5:3-5 (Ex. 1104).) CO2 lasers,
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`which generally operate at a wavelength of 10.6 µm, were commonly used during
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`the 1970s and 1980s because they provided high power and were cost-effective at
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`the time. (See, e.g., U.S. Patent No. 4,780,608 to Cross at 5:44-47 (“Carbon
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`dioxide lasers have been used since the output therefrom is readily absorbed by
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`plasmas and they are available with very high power in both pulsed and cw
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`operating modes.”) (Ex. 1115).) It was recognized at the time of Gärtner that
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`shorter wavelength lasers could also be used. (See, e.g., id. at 5:40-52 (“[L]asers
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`other than carbon dioxide may be used for the initiation and the sustaining of the
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`continuous optical discharge plasma. For example, a Nd:YAG laser has been used
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`for the initiation step. . . . Moreover, laser heating of plasma via the inverse
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`Bremsstrahlung process varies as λ2, so that cw-laser sources having shorter
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`wavelengths such as Nd:YAG, for example, are absorbed less effectively, and
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`would require substantially greater cw-laser output power levels to sustain the
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`plasma.”) (Ex. 1115).) (Eden Decl. ¶ 47 (Ex. 1103).)
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`During the 1990s and early 2000s, laser technology for shorter wavelengths
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`(i.e., those up to about 2000 nm (the infrared spectral region)) improved
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`significantly because of the development of titanium-doped sapphire and rare
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`earth-doped glass fiber lasers, thus making it easier and more desirable to sustain
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`plasmas with lasers in this wavelength range. For example, at the time of Gärtner,
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`the continuous Nd:YAG laser (a garnet crystal into which neodymium atoms have
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`intentionally been introduced as an impurity) was available commercially and
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`supplied tens of watts but was physically large (several feet in length, not including
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`the power supply). (Eden Decl. ¶ 48 (Ex. 1103).)
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`By the early 2000s, however, rare earth-doped fiber lasers were capable of
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`supplying more than 100 watts from a compact package. For example, “Since the
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`mid-1990s, high power Yb-doped fiber lasers have progressed rapidly from 2 W in
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`1995 [134], to 20 W [141] and 35 W [143] in 1997, and 110 W in 1999 [61], the
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`published record at the time of this writing.” (Michel Digonnet, Rare Earth Doped
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`Fiber Lasers and Amplifiers 148 (2d ed., 2001) (Ex. 1122).) The ytterbium-doped
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`glass fiber laser operates at typically 1.03 μm (1030 nm) in the infrared and, in the
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`years following Digonnet’s statement, the power available from Yb:glass fiber
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`lasers increased rapidly to hundreds of watts. (Eden Decl. ¶ 49 (Ex. 1103).)
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`Several years before the priority date for the ’841 Patent, Yb: glass fiber
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`lasers providing more than 100 W of power at 1030 nm from a compact package
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`were available commercially. (Eden Decl. ¶ 50 (Ex. 1103).) Furthermore, by
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`2004, titanium-doped lasers were available that produced at least 50 watts of power
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`over a broad range of wavelengths in the near-infrared and middle infrared regions
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`(660-1180 nm). Silfvast states, for example, that the output power of the
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`Ti:sapphire laser was “up to 50 W (cw)” and the laser wavelengths are “660-1080
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`nm.” (Silfvast, at 567 (Ex. 1106).) As a result, several compact and efficient near
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`infrared lasers became viable for sustaining plasma by the early 2000s. (Eden
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`Decl. ¶ 50 (Ex. 1103).)
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`Lasers operating in the shorter wavelength range (up to about 2000 nm)
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`were known to have several advantages relative to longer wavelength lasers. For
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`example, according to the Handbook of Laser Technology and Applications,
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`published in 2004, “Nd:YAG laser light [at 1.06 µm] can travel through glass (CO2
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`light cannot). This means that high-quality glass lenses can be used to focus the
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`beam down to a minimum spot size.” (Handbook of Laser Technology and
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`Applications, Vol. III at 1601 (“Handbook of Laser Tech.”) (Ex. 1116).)
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`Additionally, as recognized by the handbook, “quartz optical fibres can be
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`employed to carry the beam [from Nd:YAG laser light at 1.06 µm] relatively long
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`distances (hundreds of metres) . . . .” (Id.) It was also well-known in the early
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`2000s that the beam quality provided by a glass fiber laser is excellent and allows
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`one to focus the beams to spot sizes that are quite close to the smallest allowed by
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`the wavelength of the laser light. This represented an enormous advantage, relative
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`to the carbon dioxide laser, for example, in producing plasmas with a laser. (Eden
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`Decl. ¶ 51 (Ex. 1103).)
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`Two additional advantages of shorter wavelength lasers are that several of
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`them are considerably smaller and more efficient than CO2 lasers. For example,
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`“Commercially available cw CO2 lasers range in power from 6 watts to 10,000
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`watts, and custom lasers are available at even higher powers. Small (2 to 3 feet
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`long) CO2 lasers can produce hundreds of watts of average power at an efficiency
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`of 10%.” (Kelin Kuhn, Laser Engineering, 385 (1998) (Ex. 1123).) Therefore,
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`even a “small” CO2 laser was 2 to 3 feet in length and these numbers do not
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`include the laser’s power supply. In contrast, rare earth-doped fiber lasers also
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`produced hundreds of watts by 2004, and did so in a much smaller package.
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`Furthermore, since the laser is itself a fiber, it is a simple matter to direct the beam
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`to the chamber of the light source. Finally, it is not unusual for the efficiency of a
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`diode laser-pumped fiber laser to exceed 50%. (Eden Decl. ¶ 52 (Ex. 1103).)
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`In fact, the ’841 patent acknowledges that shorter wavelength lasers with
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`these known advantages had recently become available. (’841 patent, 16:6-14
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`(“Efficient, cost effective, high power lasers (e.g., fiber lasers and direct diode
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`lasers) are recently available in the NIR (near infrared) wavelength range from
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`about 700 nm to about 2000 nm. Energy in this wavelength range is more easily
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`transmitted through certain materials (e.g., glass, quartz and sapphire) that are
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`more commonly used to manufacture bulbs, windows and chambers. It is therefore
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`more practical now to produce light sources that operate using lasers in the 700 nm
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`to 2000 nm range than has previously been possible.”) (Ex. 1101).) (Eden Decl. ¶
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`53 (Ex. 1103).)
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`As a result, by