UNITED STATES PATENT AND TRADEMARK OFFICE BEFORE THE PATENT TRIAL AND APPEAL BOARD. ENERGETIQ TECHNOLOGY, INC., Patent Owner. Case IPR

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1 DOCKET NO.: US1 Filed By: Donald R. Steinberg, Reg. No. 37,241 David L. Cavanaugh, Reg. No. 36,476 Michael H. Smith, Reg. No. 71, State Street, Boston, Massachusetts Tel: (617) 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 IPR PETITION FOR INTER PARTES REVIEW OF U.S. PATENT NO. 8,309,943 CLAIMS 1, 3, 13, AND 16

2 TABLE OF CONTENTS Page I. MANDATORY NOTICES... 1 A. Real Parties-in-Interest... 1 B. Related Matters... 1 C. Counsel... 1 D. Service Information... 1 II. CERTIFICATION OF GROUNDS FOR STANDING... 2 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 943 PATENT... 3 A. Summary of the Prosecution History... 5 VI. CLAIM CONSTRUCTION... 6 A. Light source... 7 VII. THE CHALLENGED CLAIMS ARE UNPATENTABLE... 9 A. Laser Sustained Plasma Light Sources Were Known Long Before the Priority Date of the 943 Patent... 9 VIII. GROUNDS FOR FINDING THE CHALLENGED CLAIMS INVALID IX. A. Ground 1: Claims 1, 3, 13, and 16 are obvious over Gärtner B. Ground 2: Claims 1, 3, 13 and 16 are obvious over Gärtner in view of Hiura Claims 1, 3, 13, C. Ground 3: Claims 1, 3, 13 and 16 are obvious over Gärtner in view of Ikeuchi Claims 1, 3, 13, RESPONSE TO ARGUMENTS RAISED BY PATENT OWNER IN ITS PRELIMINARY INJUNCTION MOTION i

3 A. Patent Owner s Arguments Regarding the Content of the Prior Art B. Motivation to Combine C. Patent Owner s Arguments Regarding Objective Indicia of Non-Obviousness X. CONCLUSION ii

4 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. 8,309,943 ( the 943 patent, Ex. 1001) is one member of a patent family of continuation and divisional applications. Exhibit 1002 shows the U.S. members of this patent family and the relationships among them. Petitioners are also seeking inter partes review of related U.S. Patent Nos. 7,435,982 ( the 982 patent ); 7,786,455 ( the 455 patent ); 8,525,138 ( the 138 patent ); and 8,969,841 ( the 841 patent ). Petitioners request that the inter partes reviews of the ʼ943, 982, 455, 138 and 841 patents be assigned to the same Panel for administrative efficiency. The following litigation matter would affect or be affected by a decision in this proceeding: Energetiq Tech., Inc. v. ASML Netherlands B.V. et al, Civil Action No.: 1:15-cv 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) D. Service Information 1

5 Donald R. Steinberg, Post and Hand Delivery: WilmerHale, 60 State St., Boston MA Telephone: Facsimile: II. CERTIFICATION OF GROUNDS FOR STANDING Petitioners certify pursuant to Rule (a) that the patent for which review is sought is available for inter partes review and that Petitioners are not barred or estopped from requesting an inter partes review challenging the patent claims on the grounds identified in this Petition. III. OVERVIEW OF CHALLENGE AND RELIEF REQUESTED Pursuant to Rules 42.22(a)(1) and (b)(1)-(2), Petitioners challenge claims 1, 3, 13 and 16 of the 943 patent ( the challenged claims ) and request that 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. 1006), 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. See 35 U.S.C. 314(a). B. Prior Art Patents and Printed Publications Relied Upon Petitioners rely upon the following patents and printed publications: 2

6 1. French Patent Publication No. FR A1, published May 3, 1985 ( Gärtner, Ex. 1003), and is prior art to the ʼ943 patent under 35 U.S.C. 102(b). 2. U.S. Patent Publication No. US2005/ , filed April 11, 2003, published October 13, 2005 ( Hiura, Ex. 1004), and is prior art to the ʼ943 patent under 35 U.S.C. 102(a), 102(b), and/or 102(e). 3. Japanese Patent Publication No. JP , published November 7, 2003 ( Ikeuchi, Ex. 1005), and is prior art to the ʼ943 patent under 35 U.S.C. 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 IV. PERSON OF ORDINARY SKILL IN THE ART A person of skill in the art at the time of the alleged invention of the 943 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. (Eden Decl. 23 (Ex. 1006).) V. OVERVIEW OF THE 943 PATENT The 943 patent is directed to a laser sustained plasma light source for use in 3

7 testing and inspection for semiconductor manufacturing. As depicted in Fig. 15A below, the light source includes a chamber (green), an ignition source 1529a and 1529b (blue) for igniting a plasma, a laser 1524 (purple) for providing energy to the plasma (yellow) to produce a high brightness light, and a suspended blocker 1550 (red) to prevent laser energy from escaping. ( 943 patent, 28:14-30, 58-67; 29:1-9; claim 1(Ex. 1001).) (Eden Decl. 24 (Ex. 1006).) The alleged invention involves using a laser to provide energy to sustain the plasma for a light source. According to the 943 patent, the prior art relied upon the electrodes used for ignition to also sustain the plasma, which resulted in wear 4

8 and contamination. ( 943 patent, 1:31-46 (Ex. 1001).) Thus, a need arose for a way to sustain plasma without relying on an electrical discharge. Id. The alleged invention also involves the use of a suspended blocker to absorb or reflect laser energy not absorbed by the plasma. ( 943 patent, 9:17-30 (Ex. 1001)); (Eden Decl. 25 (Ex. 1006).) As discussed below, there was nothing new about sustaining a plasma with a laser to produce high brightness light and using a blocker to absorb or deflect laser energy. Multiple prior art references, including Gärtner and Hiura, disclosed lasersustained plasma light sources with the same elements as the 943 patent: a chamber, an ignited plasma, a laser, and suspended blocker. A. Summary of the Prosecution History The 943 patent (Ex. 1001) issued from U.S. Patent Appl. No. 13/099,823, filed on May 3, The 943 patent application is a continuation of U.S. Patent No. 7,989,786 ( 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, On August 3, 2013, the claims were allowed after an Examiner-initiated interview. The interview summary notes that independent claim 1 was amended, claim 2 was canceled, and claim 6 was rewritten in independent form. (Examiner Initiated Interview Summary dated Aug. 6, 2012 (Ex. 1009).) The Notice of Allowance states that the key element of the applicant s invention, not disclosed in prior art 5

9 but present in all of the independent claims, is that the blocker suspended along a path the energy travels blocks or reflects the energy provided to the ionized medium that is not absorbed by the ionized medium. (Notice of Allowance dated Aug. 6, 2012, at 3-4 (Ex. 1010).) The 943 patent issued on November 13, ( 943 Patent (Ex. 1001).) The 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. VI. CLAIM CONSTRUCTION A claim in inter partes review is given the broadest reasonable construction in light of the specification of the patent in which [they] appear[]. 37 C.F.R (b). Any claim term which lacks a definition in the specification is also given a broad interpretation. In re ICON Health and Fitness, Inc., 496 F.3d 1374, 1379 (Fed. Cir. 2007). 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. 48,764, 48,766-48,767 (Aug. 14, 2012). Consistent with this standard, this section proposes, under the broadest reasonable construction standard, constructions of terms that lack a definition in 6

10 the specification 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. (See Eden Decl. 23 (defining level of ordinary skill) (Ex. 1006).) A. Light source The term light source is recited in challenged claims 1 and 3. 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. at 28 (Ex. 1006).) 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 ultraviolet (100 nm to 200 nm), ultraviolet (200 nm to 400 nm), visible (400 to The term light is sometimes used more narrowly to refer only to visible light. However, references to ultraviolet light in the 943 patent make clear that the broader meaning is intended because ultraviolet light has a wavelength shorter than that of visible light. (See, e.g., 943 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. 1001).) (See Eden Decl. 29 n. 1 (Ex. 1006).). 7

11 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., Silfvast, LASER FUNDAMENTALS, at 4 (Ex. 1007)).) 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. 1008) (Eden Decl. 29 (Ex. 1006).) The 943 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 943 patent states that parameters such as the wavelength of the light from a light source vary depending upon the application. ( 943 patent, 1:29-30 (Ex. 1001).) The 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). ( 943 patent, 15:10-11 (Ex. 1001); see also id. at 13:54-56 (discussing the ultraviolet light 136 generated by the plasma 132 of the light source 100) (Eden Decl. 30 (Ex. 1006).) 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 8

12 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. 31 (Ex. 1006).) VII. THE CHALLENGED CLAIMS ARE UNPATENTABLE A. Laser Sustained Plasma Light Sources Were Known Long Before the Priority Date of the 943 Patent When the application that led to the 943 patent was filed, there was nothing new about a light source using an ignition source to generate a plasma in a chamber, a laser to sustain the plasma to produce high brightness light from the plasma, and a blocker (or a beam dump ) to absorb or deflect unused laser energy. 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 et al. filed a patent application entitled Radiation source for optical devices, notably for photolithographic reproduction systems, which published on May 3, 1985 as French Patent Application No (Ex. 1003). Gärtner discloses a light source with the same features claimed in the 943 patent: (1) a sealed chamber (green); (2) an ignition source pulsed laser 10 (blue), which generates a plasma (within the yellow box); (3) a laser (purple), which provides energy to the plasma (yellow) to produce light; and (4) a blocker to absorb or reflect laser energy unabsorbed by the plasma (red). (See, e.g., Gärtner at 4-5; Fig. 9

13 1, 2 (Ex. 1003); Eden Decl. 32 (Ex. 1006).) 943 patent, Fig. 15A (Ex. 1001) Gärtner, Fig. 1 (Ex. 1003) In addition, on April 11, 2003, Hiura filed U.S. Patent Application No. 2005/ entitled Exposure Apparatus and Device Fabrication Method Using the Same. Hiura describes an exposure apparatus containing a laser plasma light source. As shown in Fig. 10, reproduced below, Hiura discloses a laser sustained plasma light source with features similar to the 943 patent: (1) a chamber 180 (green); (2) an ignited plasma 104 (yellow); (3) laser 100 (purple) for providing energy in the form of beam 101 to the plasma; and (4) a blocker 150 (red) to absorb and/or reflect laser energy unabsorbed by the plasma. (See, e.g., Hiura, 0012, 0017, 0039, , Fig. 10 (Ex. 1004).) Hiura specifically states that stopper 150 includes a triangle part 155 that reflects laser, and absorbs it as a result of multiple reflection. (Hiura 0079 (Ex. 1004)) (Eden 10

14 Decl. 33 (Ex. 1006).) Hiura Fig. 10 (Ex. 1004) Further, on April 26, 2002, Ikeuchi filed a patent application entitled Light radiation apparatus, which published as Japanese Patent No. JP on November 7, (Ex ) Ikeuchi discloses a continuous high-power light source using ignited plasma. As shown in Fig. 1, reproduced below, Ikeuchi discloses a light source with features similar to the 943 patent: (1) a sealed chamber 10 (green); (2) an ignited plasma (yellow); (3) an external energy source (purple) to sustain the plasma to emit a high brightness light; and (4) an electromagnetic radiation absorber 11 and an absorbent window 7 (i.e., blockers) (red) to prevent unabsorbed electromagnetic energy from escaping the radiation apparatus. (See, e.g., Ikeuchi, 0002, 0006, 0010, 0034, and 0046, Fig. 1 (Ex. 11

15 1005).) (Eden Decl. 34 (Ex. 1006).) Ikeuchi, Fig. 1 (Ex. 1005) Thus, the purportedly novel features of the 943 patent are nothing more than the standard features of laser sustained plasma light sources across several generations of technology from the 1980 s to the early 2000 s. (Eden Decl. 35 (Ex. 1006).) VIII. GROUNDS FOR FINDING THE CHALLENGED CLAIMS INVALID Pursuant to Rule (b)(4)-(5), specific grounds for finding the challenged claims invalid are identified below and discussed in the Eden Declaration (Ex. 1006). These grounds demonstrate in detail that claims 1, 3, 13, and 16 are invalid under 35 U.S.C A. Ground 1: Claims 1, 3, 13, and 16 are obvious over Gärtner Gärtner discloses and renders each limitation of Claims 1, 3, 13, and 16 obvious. To the extent the Patent Owner asserts that these features are not 12

16 disclosed in a single embodiment of Gärtner, it would have been obvious to combine features discussed in connection with various exemplary figures in Gärtner. Gärtner is prior art under 35 U.S.C. 102(b) because it was published more than a year before the earliest claimed priority date for the 943 patent, which is March 31, Gärtner was not considered by the Examiner during prosecution of the 943 patent. 1. Overview of Gärtner Gärtner describes a light source for optical systems: The present invention relates to a radiation source for optical devices, in particular for photolithographic reproduction systems. (Gärtner at 1:1-2 (Ex. 1003).) (Eden Decl. 39 (Ex. 1006).) Gärtner is directed to the same problem as the 943 patent, namely, producing light that is brighter than that produced by conventional 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 photolithographic appliances for illuminating a photoresist layer on a semiconductor wafer. ) (Ex. 1003) with 943 patent, 1:31-49 ( The state of the art in, for example, wafer inspection systems involves the use of xenon or mercury arc lamps to produce 13

17 light.... [T]hese arc 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. 1001).) (Eden Decl. 40 (Ex. 1006).) Gärtner proposes the same solution as the 943 patent, albeit over 20 years earlier: (1) a chamber, (2) an ignition source, (3) a laser to provide energy to a plasma, and (4) a blocker. (Compare Gärtner at 4:31-35, 5:1-9, Fig. 1 (Ex. 1003) with 943 patent, 1:66-2:3, 9:15-17; Fig. 15A (Ex. 1001).) For example, as shown below, Figure 1 of Gärtner shows a gas-tight chamber 1 (green); laser 10 (blue) for generating the plasma 14 (yellow); a laser 9 (purple) for producing radiation (light) from the plasma (yellow); and concave mirror 12 (red) (i.e., a blocker) for blocking radiation from the laser that is not absorbed by the plasma and reflecting that radiation back toward the plasma. (Gärtner at 4-5 (Ex. 1003).) (Eden Decl. 41 (Ex. 1006).) 14

18 943 patent, Fig. 15A (Ex. 1001) Gärtner, Fig. 1 (Ex. 1003) The system in Gärtner operates in the same manner as the system described in the 943 patent. In particular, Gärtner explains that gas-tight chamber 1 contains a discharge medium 2. (Compare Gärtner at 4:32 ( gas-tight chamber 1 contains the discharge medium 2 ) (Ex. 1003) with 943 patent, 11:15-16 ( light source 100 includes a chamber 128 that contains an ionizable medium (not shown). ) (Ex. 1001).) The discharge medium 2 is an ionizable gas such as xenon. (Compare Gärtner at 5:15-16 (describing using argon or xenon atmosphere as active medium ) (Ex. 1003) with 943 patent, 3:47-50 ( [T]he ionizable medium can be... Xe, Ar.... ) (Ex. 1001).) (Eden Decl. 42 (Ex. 1006).) Gärtner s laser 10 is an ignition source that ionizes the discharge medium 2. (Compare Gärtner at 5:5-7 ( The radiation 13 from the laser 10, which is a 15

19 nitrogen pulse laser, is focussed on the same point by the lens 7 which allows ultraviolet to pass and produces an electrical discharge there and as a result an absorbent plasma ) (Ex. 1003) with 943 patent, 12:19-21 ( The ignition source 140 generates an electrical discharge in the chamber 128 (e.g., the region 130 of the chamber 128) to ignite the ionizable medium. ), 14:28-33 ( Alternative types of ignition sources 140 that can be used in the light source 100 include... pulsed lasers.... ) (Ex. 1001).) (Eden Decl. 43 (Ex. 1006).) Gärtner s laser 9 is a laser that provides energy to the ionized gas within the chamber to produce a high brightness light. (Compare Gärtner at 5:7-9 ( absorbent plasma 14 which is heated to high temperatures under the influence of the radiation 11 [from laser 9]. The radiation 15 from the plasma can be fed into the downstream optical system through the window 8. ) (Ex. 1003) with 943 patent, 11:22-25 ( 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 and/or sustain the high brightness light 136. ) (Ex. 1001).) (Eden Decl. 44 (Ex. 1006).) Gärtner also discloses the use of blockers for preventing energy from escaping. Gärtner s concave mirror 12, concave mirror 39, and the output window constitute blockers suspended along a path the energy travels and serve to block the energy provided to the ionized medium that is not absorbed by the ionized 16

20 medium. In particular, mirrors 12 and 39 block radiation from lasers 9 and 39 that is not absorbed by the plasma and reflect that radiation back toward the plasma; and the output window in Figure 4 blocks radiation from laser 38 that is not absorbed by the plasma, while allowing the light from the plasma to exit the light source. (Compare Gärtner Figs. 1-4 (Ex. 1003) with 943 patent 28:58-60 ( the blocker 1550 is a mirror that deflects the laser energy 1556 that is not absorbed by the plasma away from the opening ); 29:40-42 ( the laser energy blocker 1550 is made of a material that absorbs, rather than reflects, the laser energy 1556 (Ex. 1001).) (Eden Decl. 45 (Ex. 1006).) 943 patent, Fig. 15A (Ex. 1001) Gärtner, Fig. 1 (Ex. 1003) 17

21 Gärtner, Fig. 3 (Ex. 1003) Gärtner, Fig. 4 (Ex. 1003) 2. Claims 1, 3, 13, and 16 As illustrated below, Gärtner renders every limitation of claims 1, 3, 13, and 16 of the 943 patent obvious. (See Eden Decl. 46 (Ex. 1006).) Gärtner describes a light source for optical devices and discloses the key components of the 943 patent: (1) a chamber, (2) an ignition source to ionize the gas, (3) a laser to provide energy to the ionized gas (plasma) to sustain the plasma for providing light, and (4) a blocker. (Gärtner at 1, Fig. 2 (Ex. 1003).) 3. Independent Claim 1 is obvious over Gärtner a) Claim 1 - Preamble (element [1p]) The Preamble of claim 1 recites a light source. ( 943 Patent, 30:35 (Ex. 1001).) Gärtner discloses a light source. Particularly, the reference discloses a radiation source for optical devices, which is a light source. (Gärtner at 1:1, Figs. 1-4 (Ex. 1003).) Gärtner s light source can be used for applications such as illuminating a photoresist. (Gärtner at 1:4 (Ex. 1003); see also 943 patent at 18

22 1:31-32 (recognizing light sources were known in the art) (Ex. 1001).) (Eden Decl. 47 (Ex. 1006).) b) Claim 1 - Chamber and Ignition Source (elements [1a], [1b]) Claim 1 recites a chamber. ( 943 Patent, 30:36 (Ex. 1001).) Gärtner discloses a chamber. For example, Gärtner discloses a gas-tight chamber. (Gärtner at 3:20; 4:32; 5:3, Fig. 1 ( gas-tight chamber 1 ); see also 5:27-28, Fig. 2 ( A casing 16, the concave mirror 17 and the quartz window 18 constitute the gastight chamber containing the discharge medium 19. ); 6:9, Figs. 3-4 ( discharge chambers 35 and 36 ) (Ex. 1003); see also 943 patent at 1:31-34 (recognizing light source chambers were known in the art) (Ex. 1001).) (Eden Decl. 48 (Ex. 1006).) Claim 1 further recites an ignition source for ionizing a medium within the chamber. ( 943 Patent, 30:37-38 (Ex. 1001).) Gärtner s gas-tight chamber contains a discharge medium such as argon or xenon, and Gärtner s laser 10 is an ignition source for ionizing the medium. (Gärtner at 4:32, 5:5-7, 5:15-16 (Ex. 1003).) In particular, laser 10 is a nitrogen pulse laser that produces an electrical discharge in the medium to create absorbent plasma 14. (Gärtner at 5:5-7 (Ex. 1003).) Gärtner also discloses electrodes as an ignition source. (Gärtner at 1:22 ( the electrodes of the discharge cavity ) (Ex. 1003).) Thus, Gärtner discloses both electrode and pulsed laser ignition sources for ionizing a 19

23 medium within the chamber. (Eden Decl. 49 (Ex. 1006).) c) Claim 1 - Laser providing energy to the ionized medium within the chamber to produce a light (element [1c]) Claim 1 recites a laser for providing energy to the ionized medium within the chamber to produce a light. ( 943 Patent, 30:39-40 (Ex. 1001).) Gärtner discloses a laser that provides energy to the ionized medium within the chamber to produce light. (Eden Decl. 50 (Ex. 1006).) For example, Gärtner teaches the production and maintenance of a radiation-emitting plasma in the discharge medium are ensured, in a known manner, by at least one laser situated outside the chamber... (Gärtner at 3:22-24 (Ex. 1003).) Gärtner shows continuous laser 9, which is a stationary CO 2 gas laser, in Figure 1 as an example of such a laser. (Gärtner at 5:3-4, 11-12; see also id. at 5:7-9 ( absorbent plasma 14 which is heated to high temperatures under the influence of the radiation 11 [from laser 9]. The radiation 15 from the plasma can be fed into the downstream optical system through the window 8. ) (Ex. 1003).) (Eden Decl. 50 (Ex. 1006).) d) Claim 1 - Blocker (elements [1d]) Claim 1 recites a blocker suspended along a path the energy travels and blocking the energy provided to the ionized medium that is not absorbed by the ionized medium. ( 943 Patent at 30:41-43 (Ex. 1001).) Gärtner discloses a blocker suspended along a path the energy travels and blocking the energy provided to the ionized medium that is not absorbed by the ionized medium, as 20

24 recited in the claim. For example, Gärtner s concave mirror 12 in Fig. 1 is a blocker suspended along a path the energy travels and serves to block the energy provided to the ionized medium that is not absorbed by the ionized medium. In particular, concave mirror 12 is mounted on the wall of the chamber along a path radiation 11 from laser 9 travels. (Gärtner at 5:4-5 (Ex. 1003).) Concave mirror 12 serves to block the laser energy provided to the plasma 14 that is not absorbed by the plasma 14. Indeed, like an embodiment of the 943 patent, concave mirror 12 blocks this laser energy by reflecting it back toward the plasma 14. (Cf. 943 patent, 29:33-36 ( In some embodiments, the blocker 1550 is configured to reflect the laser energy 1556 back toward the ionized medium in the chamber ) (Ex. 1001).) (Eden Decl. 51 (Ex. 1006).) Gärtner also discloses a blocker positioned between the laser and an output of the light source as depicted in Figure 15A of the 943 patent. For example, in Figure 3, concave mirror 39 is a blocker suspended along a path the energy travels and serves to block the energy provided to the ionized medium that is not absorbed by the ionized medium. Like the arrangement in Figure 15A of the 943 patent, concave mirror 39 is positioned between the laser 38 and the output of the light source. Additionally, like an embodiment of the 943 patent, concave mirror 39 blocks the beam 37 by reflecting it toward plasma 41. (Cf. 943 patent, 29:33-36 ( In some embodiments, the blocker 1550 is configured to reflect the laser energy 21

25 1556 back toward the ionized medium in the chamber ) (Ex. 1001).) Additionally, concave mirror 39 is suspended along a path the energy travels because it is attached to the output window in the path the laser energy travels. (Eden Decl. 52 (Ex. 1006).) Similarly, in Figure 4, Gärtner discloses an output window that is a blocker suspended along a path the energy travels and blocking the energy provided to the ionized medium that is not absorbed by the ionized medium. In particular, in Figure 4, lens 40 focuses the beam 37 into the plasma 42. (Gärtner at 6:10-12 (Ex. 1003).) The output window absorbs the remainder of the laser energy provided to the plasma that is not absorbed by the plasma. A person of skill in the art would appreciate that the output window in Fig. 4 is quartz. First, Gärtner discloses that the output window 18 in Fig. 2 is quartz. (See, e.g., Gärtner at 5:22-24, 27 (Ex. 1003).) Thus, a person of skill in the art would understand that the output windows in the other figures are also quartz. Additionally, quartz has several advantages with respect to other window materials. For example, quartz is transparent to the ultraviolet light produced by the plasma and absorbs infrared radiation produced by the CO 2 laser. Also, quartz is inexpensive compared with some other materials (such as CaF2 and sapphire) and relatively easy to obtain in a variety of sizes. Therefore, a person of skill in the art would expect that the output window in Fig. 4 is quartz. Accordingly, the output window absorbs the energy provided to the 22

26 plasma that is not absorbed by the plasma. Additionally, the output window is suspended along a path the beam travels because it lies squarely in the path of the beam and is sealed onto mirror 44. (Eden Decl. 53 (Ex. 1006).) Gärtner, Fig. 1 (Ex. 1003) Gärtner, Fig. 3 (Ex. 1003) Gärtner, Fig. 4 (Ex. 1003) Gärtner thus discloses all of these elements. The table below summarizes the disclosure of Gärtner and the limitations of claim 1. 23

27 943 Patent, Claim 1 Prior Art [1p] A light source, comprising: Gärtner at 1:1; 1:3, Figs. 1-4 [1a] a chamber; Gärtner at Figs. 1-4; 3:20; 4:32; 5:3; 5:27-28; 6:9 [1b] an ignition source for ionizing a medium within the chamber; [1c] a laser for providing energy to the ionized medium within the chamber to produce a light; and Gärtner at 1:22; 4:32; 5:5-7; 5:15-16 Gärtner at 3:22-24; 5:5-9 [1d] a blocker suspended along a path the energy travels and blocking the energy provided to the ionized medium that is not absorbed by the ionized medium. Gärtner at Figs. 1-4; 5:4-5; 5:22-24; 6:10-12 e) Motivation to combine Gärtner discloses its system by way of non-limiting examples. (Gärtner at 4:20-21 ( Embodiments of the subject of the invention are shown, by way of nonlimiting examples. ); see also 4:17-18 ( Various other characteristics of the invention further emerge from the following detailed description. ) (Ex. 1003).) (Eden Decl. 55 (Ex. 1006).) Gärtner expressly describes how features from various non-limiting examples can be combined and why it would be advantageous to do so. For example, Gärtner illustrates a pulsed laser 10 (ignition source) shown in Fig. 1. (Supra VIII.A.1.) Gärtner also describes advantages of utilizing a pulsed laser (ignition source) such as laser 10. Gärtner states, When the radiated power of a 24

28 laser as supplied is not sufficient for a discharge in the discharge medium, it is advantageous that the device includes, to ignite the discharge medium, outside the chamber, at least one further pulse-operated laser which is directed by optical means to ensure focusing of the same volume at an entry aperture. (Gärtner at 3:29-32 (Ex. 1003).) Therefore, a person of skill in the art would have been motivated to utilize a pulsed laser (ignition source) such as laser 10 illustrated in Fig. 1 in conjunction with features shown in Figs. 2-4 in order to ensure that the system had sufficient power to generate the plasma. (Eden Decl. 56 (Ex. 1006).) Additionally, Gärtner discloses quartz window 18 in Fig. 2, window 8 in Fig. 1, and unnumbered output windows in Figs. 3 and 4. These windows perform the same function of providing an output window for the light produced by the plasma. (Compare Gärtner at 5:8-9 ( The radiation 15 from the plasma can be fed into the downstream optical system through the window 8 ) with 5:34-6:1-2 ( The plasma radiation 27 is sent directly, and by means of the concave mirror 17, through the quartz window 18 to the condenser lens 29 of the optical system placed downstream. ) (Ex. 1003).) Therefore, it would be obvious to construct window 8 and the output windows in Figs. 3 and 4 from quartz because this is a known material described in connection with a corresponding element of another illustrative example of the invention. Combining features from Gärtner s various non-limiting exemplary embodiments would have required nothing more than 25

29 routine skill. A person of skill in the art would have arranged these features in various configurations to achieve the benefits described in Gärtner. Doing so would simply achieve the expected benefits expressly described in Gärtner. (Eden Decl. 57 (Ex. 1006).) Gärtner also illustrates examples of chambers with reflective surfaces in Figures 2-4. Gärtner explains advantages of including such reflectors: It is possible to advantageously simplify the realisation of the radiation source by placing optical means which ensure the focussing of the laser radiation inside and/or on the surface of the chamber. In these conditions, the inner wall of the chamber constitutes an optical means for focussing the radiation coming from outside. (Gärtner at 4:5-12 (Ex. 1003).) This further illustrates that the features disclosed in Gärtner s exemplary figures are intended to be used in combination. (Eden Decl. 58 (Ex. 1006).) 4. Independent Claim 13 is obvious over Gärtner a) Claim 13 - Preamble (elements [13p]) Claim 13 recites a method for producing light. ( 943 Patent at 31:8 (Ex. 1001).) Gärtner discloses a method of producing light. For example, Gärtner discloses a radiation source for optical devices, which is a light source that performs a method of producing light. (Gärtner at 1:1, Figs. 1-4 (Ex. 1003).) Gärtner s light source can be used for applications such as illuminating a 26

30 photoresist. (Gärtner at 1:4 (Ex. 1003); see also 943 patent at 1:31-32 (recognizing light sources were known in the art) (Ex.1001).) (Eden Decl. 59 (Ex. 1006).) b) Claim 13 - Chamber and Ignition Source (element [13a]) Claim 13 recites ionizing with an ignition source a medium within a chamber. ( 943 Patent at 31:9-10 (Ex. 1001).) Gärtner discloses ionizing with an ignition source a medium within a chamber as recited in the claim. For example, Gärtner discloses a gas-tight chamber. (Gärtner at 3:20; 4:32; 5:3, Fig. 1 ( gastight chamber 1 ); see also 5:27-28, Fig. 2 ( A casing 16, the concave mirror 17 and the quartz window 18 constitute the gas-tight chamber containing the discharge medium 19. ); 6:9, Figs. 3-4 ( discharge chambers 35 and 36 ) (Ex. 1003); 943 patent at 1:31-34 (recognizing light source chambers were known in the art) (Ex. 1001).) Gärtner s gas-tight chamber (sealed chamber) contains a discharge medium such as argon or xenon (medium). (Gärtner at 4:32, 5:15-16 (Ex. 1003).) (Eden Decl. 60 (Ex. 1006).) Gärtner s laser 10 is an ignition source for ionizing the medium within the chamber. (Gärtner at 5 (Ex. 1003).) In particular, laser 10 is a nitrogen pulse laser that produces an electrical discharge in the medium to create absorbent plasma 14. (Gärtner at 5:5-7 (Ex. 1003).) Gärtner also discloses electrodes as ignition sources for ionizing the medium within the chamber. (Gärtner at 1:22 27

31 ( the electrodes of the discharge cavity ) (Ex. 1003).) Thus, Gärtner discloses both electrode and pulsed laser ignition sources for ionizing a medium within the chamber. (Eden Decl. 61 (Ex. 1006).) c) Claim 13 - Laser providing energy to the ionized medium within the chamber to produce a light (element [13b]) Claim 13 recites providing laser energy to the ionized medium in the chamber to produce a light. ( 943 Patent at 31:11-12 (Ex. 1001).) Gärtner discloses providing laser energy to the ionized medium in the chamber to produce a light. (Eden Decl. 62 (Ex. 1006).) For example, Gärtner teaches the production and maintenance of a radiation-emitting plasma in the discharge medium are ensured, in a known manner, by at least one laser situated outside the chamber. (Gärtner at 3:22-24 (Ex. 1003).) Gärtner shows continuous laser 9, which is a stationary CO 2 gas laser, in Figure 1 as an example of such a laser. (Gärtner at 5:3-4, 11-12; see also id. at 5:7-9 ( absorbent plasma 14 which is heated to high temperatures under the influence of the radiation 11 [from laser 9]. The radiation 15 from the plasma can be fed into the downstream optical system through the window 8. ) (Ex. 1003).) (Eden Decl. 62 (Ex. 1006).) d) Claim 13 - Blocker (element [13c]) Claim 13 recites blocking energy provided to the ionized medium that is not absorbed by the ionized medium with a blocker suspended along a path the energy travels. ( 943 Patent at 31:13-15 (Ex. 1001).) Gärtner discloses a blocker 28

32 that blocks energy to the ionized medium that is not absorbed by the ionized medium with a blocker suspended along a path the energy travels. For example, Gärtner discloses concave mirror 12 in Fig. 1 that serves to block energy provided to the ionized medium that is not absorbed by the ionized medium. In particular, concave mirror 12 is mounted on the wall of the chamber along the path travelled by radiation 11 from laser 9. (Gärtner at 5:4-5 (Ex. 1003).) Concave mirror 12 blocks the laser energy provided to the plasma 14 that is not absorbed by the plasma 14. Indeed, like an embodiment of the 943 patent, concave mirror 12 blocks this laser energy by reflecting it back toward the plasma 14. (Cf. 943 patent, 29:33-36 ( In some embodiments, the blocker 1550 is configured to reflect the laser energy 1556 back toward the ionized medium in the chamber ) (Ex. 1001).) (Eden Decl. 63 (Ex. 1006).) Gärtner also discloses blocking energy with a blocker positioned between the laser and an output of the light source as depicted in Figure 15A of the 943 patent. For example, Figure 3 discloses blocking energy provided to the ionized medium that is not absorbed by the ionized medium with concave mirror 39 suspended along a path the energy travels. Like the arrangement in Figure 15A of the 943 patent, concave mirror 39 is positioned between the laser 38 and the output of the light source. Additionally, like an embodiment of the 943 patent, concave mirror 39 blocks the beam 37 by reflecting it toward plasma 41. (Cf

33 patent, 29:33-36 ( In some embodiments, the blocker 1550 is configured to reflect the laser energy 1556 back toward the ionized medium in the chamber ) (Ex. 1001).) Additionally, concave mirror 39 is suspended along a path the energy travels because it is attached to the output window in the path the laser energy travels. (Eden Decl. 64 (Ex. 1006).) Similarly, in Figure 4, Gärtner discloses blocking energy provided to the ionized medium that is not absorbed by the ionized medium with an output window suspended along a path the energy travels. In particular, in Figure 4, lens 40 focuses the beam 37 onto the plasma 42. (Gärtner at 6:10-12 (Ex. 1003).) The output window absorbs the energy provided to the plasma that is not absorbed by the plasma. A person of skill in the art would appreciate that the output window in Fig. 4 is quartz. First, Gärtner discloses that the output window 8 in Fig. 2 is quartz. (See, e.g., Gärtner at 5:27 (Ex. 1003).) Thus, a person of skill in the art would understand that the output windows in the other figures to also be quartz. Additionally, quartz has several advantages. For example, quartz is transparent to the ultraviolet light produced by the plasma and absorbs infrared radiation produced by the CO 2 laser. Also, quartz is inexpensive as compared with some other materials and is relatively easy to obtain in a variety of sizes. Therefore, a person of skill in the art would expect that the output window in Fig. 4 is quartz. Accordingly, the output window absorbs the energy provided to the plasma that is 30

34 not absorbed by the plasma. Additionally, the output window is suspended along a path the beam travels because it is in the path of the beam and is sealed to mirror 44. (Eden Decl. 65 (Ex. 1006).) Gärtner, Fig. 1 (Ex. 1003) Gärtner, Fig. 3 (Ex. 1003) Gärtner, Fig. 4 (Ex. 1003) Gärtner thus discloses all of these elements. The table below summarizes the disclosure of Gärtner and the limitations of claim

35 943 Patent, Claim 13 Prior Art [13p] A method for producing light, comprising: [13a] ionizing with an ignition source a medium within a chamber; [13b] providing laser energy to the ionized medium in the chamber to produce a light; and [13c] blocking energy provided to the ionized medium that is not absorbed by the ionized medium with a blocker suspended along a path the energy travels. Gärtner at 1:1; 1:3, Figs. 1-4 Gärtner at Figs. 1-4; 1:22; 3:20-21; 4:32; 4:33; 5:3; 5:5-7; 5:15-16; 5:27-28; 6:9 Gärtner at 3:22-24; 5:7-9; 5:11-12 Gärtner at Figs. 1-4; 5:4-5; 5:22-24; 6:10-12 e) Motivation to Combine As discussed supra in Section VIII.A.3.e), it would have been obvious to combine features from Gärtner s various non-limiting exemplary embodiments. 5. Dependent Claims (claims 3, 16) As shown below, Gärtner discloses every limitation of dependent claims 3 and 16. (See Eden Decl. 68 (Ex. 1006).) a) a blocker that absorbs energy (claims 3 and 16) Gärtner also discloses claim 3 which depends from claim 1 and additionally recites the blocker absorbs the energy provided to the ionized medium that is not absorbed by the ionized medium, and claim 16 which depends from claim 13, and additionally recites wherein blocking the energy comprises absorbing the energy. ( 943 Patent at 30:46-48; 32:3-4 (Ex. 1001).) (Eden Decl. 69 (Ex. 1006).) 32

36 For example, the output window in Fig. 4 blocks laser energy by absorbing it. (Eden Decl. 70 (Ex. 1006).) Gärtner, Fig. 4 (Ex. 1003) As discussed previously for claims 1 and 13, the output window in Figure 4 absorbs the energy provided to the plasma that is not absorbed by the plasma. A person of skill in the art would appreciate that the output window in Fig. 4 is quartz. First, Gärtner discloses that the output window 18 in Fig. 2 is quartz. (See, e.g., Gärtner at 5:27 (Ex. 1003).) Thus, a person of skill in the art would understand that the output windows in the other figures are also quartz. Additionally, quartz has several advantages. For example, quartz is transparent to the ultraviolet light produced by the plasma and absorbs infrared radiation produced by the CO 2 laser. Also, quartz is inexpensive as compared with some other materials and is relatively easy to obtain in a variety of sizes. Therefore, a person of skill in the art would expect that the output window in Fig. 4 is quartz. 33

37 Accordingly, the output window absorbs the energy provided to the plasma that is not absorbed by the plasma. (Eden Decl. 71 (Ex. 1006).) b) Motivation to Combine As discussed supra in Section VIII.A.3.e), it would have been obvious to combine features from Gärtner s various non-limiting exemplary embodiments. B. Ground 2: Claims 1, 3, 13 and 16 are obvious over Gärtner in view of Hiura Claims 1, 3, 13 and 16 relate to a laser sustained plasma light source and a blocker that blocks (deflects or absorbs) energy provided to the plasma that is not absorbed by the plasma. These claims are obvious over Gärtner in view of Hiura. (Eden Decl. 73 (Ex. 1006).) Hiura is prior art under 35 U.S.C. 102(a), (b) 2 and/or (e) because it was filed April 11, 2003 and published October 13, The blocker claimed in the challenged claims of the 943 patent was first disclosed in the 786 patent. (See, e.g., ʼ786 patent, 9:16-64 (Ex. 1015).) (Eden Decl. 73, n.2 (Ex. 1006).) The word blocker does not appear once in the ʼ455 patent, the parent of the ʼ786 patent. (See generally ʼ455 patent (Ex. 1016).) (Eden Decl. 73, n.2 (Ex. 1006).) Thus, the challenged claims of the 943 patent can only properly establish a priority date to the 786 patent filing date of July 2, Because Hiura was published more than a year before July 2, 2008, it is therefore prior art under 35 U.S.C. 102(b) to challenged claims 1, 3, 13, and

38 Hiura was also not considered by the Examiner during prosecution of the 943 patent. 1. Claims 1, 3, 13, 16 As discussed above for Ground 1, Gärtner renders obvious claims 1, 3, 13 and 16. (Supra at VIII.A.) a) a blocker that blocks energy that is not absorbed by the ionized medium (Claims 1 and 13) The Patent Owner may argue that Gärtner does not disclose element [1d], which recites a blocker suspended along a path the energy travels and blocking the energy provided to the ionized medium that is not absorbed by the ionized medium, and element [13c] which recites blocking energy provided to the ionized medium that is not absorbed by the ionized medium with a blocker suspended along a path the energy travels. ( 943 Patent at 30:41-43; 31:13-15 (Ex. 1001).) For example, in related litigation, Patent Owner has argued that Gärtner does not disclose a blocker that absorbs energy. (See Second Declaration of Donald K. Smith, Ph.D. in Support of Energetiq s Reply Brief in Support of its Motion for Preliminary Injunction, dated March 17, 2015 ( Second 35

39 Smith Decl. ) 63) (Ex. 1011).) 3 Patent Owner is incorrect. (Supra section VIII.A.3.c.) However, to the extent Gärtner does not disclose the claimed blocker, it would have been obvious to combine Hiura s teaching of a stopper 150 with Gärtner to block the laser energy that is not absorbed by the ionized medium (i.e., the plasma). (Eden Decl. 75 (Ex. 1006).) As shown below, Hiura s stopper 150 is essentially identical to the 943 patent s blocker In both figures, the lasers provide energy (1524 and 101) through an opening in a curved mirror (1540 and 108). ( 943 patent Fig. 15A (Ex. 1001), Hiura Fig. 10 (Ex. 1004).) Both figures include a blocker (1150 and 150) suspended along a path the energy travels and blocking the energy provided to the ionized medium that is not absorbed by the ionized medium. (Id.) (Eden Decl. 76 (Ex. 1006).) 3 Patent Owner has also argued in related litigation that Ikeuchi, the secondary reference for Ground III, is not combinable with Gärtner because it uses microwave power from a gyrotron to produce a plasma. (See Second Smith Declaration 62 (Ex. 1011).) Patent Owner is mistaken because the way in which the plasma is generated in Ikeuchi is irrelevant to the function of the blocker in Ikeuchi. (See infra IX.B.) Regardless, Patent Owner s argument does not apply to Hiura, which generates the plasma with a laser. (Eden Decl. 75, n. 3 (Ex. 1006).) 36

40 943 patent, Fig. 15A (Ex. 1001) Hiura, Fig. 10 (excerpt)(ex. 1004) Hiura explicitly discloses that stopper 150 can absorb the laser energy. For example, Hiura states that stopper 150 on the optical axis AA [shields] a propagation of the pulse laser beam 101 and absorbs the pulse laser beam. (Hiura 0064 (Ex. 1004).) The stopper 150 is made of materials or has a shape for absorbing the pulse laser beam without reflecting the laser beam. (Hiura 0064 (Ex. 1004); cf. 943 patent, 29:40-42 ( In some embodiments, the laser energy blocker 1550 is made of a material that absorbs, rather than reflects, the laser energy 1556 (e.g., graphite). ) (Ex. 1001).) Figures 1 and 10 of Hiura show that the stopper 150 is suspended in the path of the laser beam and absorbs light. In particular, like blocker 1550 in Figure 15A of the 943 patent, stopper 150 is held in suspension squarely in the path of the laser beam. ( 943 patent Fig. 15A (Ex. 1001), Hiura Figs. 1, 10 (Ex. 1004).) (Eden Decl. 77 (Ex. 1006).) Hiura also discloses a reflective member 153 (red) in Fig. 11 suspended in the path of the pulse laser beam 101 that reflects laser energy toward the stopper 37

41 150, where the energy is absorbed. 4 (Hiura Fig. 11 (Ex. 1004).) Therefore, like the 943 patent, Hiura also includes embodiments (in this case, reflector 153) where the blocker blocks the laser energy by reflecting (deflecting) it. (Eden Decl. 78 (Ex. 1006).) Hiura Fig. 11 (Ex. 1004) Therefore, Gärtner in combination with Hiura discloses the light source comprising a blocker suspended along a path the energy travels and blocking the energy provided to the ionized medium that is not absorbed by the ionized medium, as recited by claim 1, and blocking energy provided to the ionized medium that is not absorbed by the ionized medium with a blocker suspended 4 The reflective member 153 in Figure 11 of Hiura corresponds to the reflective member 157 described in paragraph (See Hiura 0081, Fig. 11 (Ex. 1004).) This paragraph describes the embodiment in Figure

42 along a path the energy travels, as recited by claim 13. (Eden Decl. 79 (Ex. 1006).) b) Motivation to Combine For many decades, blockers have been used in optical systems to block and absorb energy. Optical blockers, more commonly known as beam dumps or beam stops, have a long history in optics and lasers. Early in the 20th century, Robert Wood invented the Wood s horn, which traps and absorbs light in a manner similar to that of stopper 150 in Hiura. A motivation to use a blocker is the desire to prevent light of one wavelength (such as that of laser 10 in Gärtner) from reaching the remainder of an optical system. That is, the intent of the system is to employ the light produced by a laser sustained plasma, and not the laser light itself. For this reason, one or more optical components designed to prevent the laser light in Gärtner from proceeding into successive stages of the optical system is desirable. Indeed, installing such blockers is an essential aspect of optical system engineering. (Eden Decl. 80 (Ex. 1006).) Using blockers in Gärtner (in addition to what is shown in Gärtner, as discussed above) is advantageous for a number of reasons. First, blockers can prevent unabsorbed laser energy from escaping the chamber and causing damage outside the chamber. As shown in Hiura, the blocker absorbs laser energy, which prevents unabsorbed laser energy from exiting the chamber and causing damage to 39

43 components of the optical system. (Hiura 0012 (Ex. 1004).) This is the same advantage described in the 943 patent itself blockers can prevent laser energy that is not absorbed by the plasma from exiting the chamber, which may alter the light output from the light source. ( 943 Patent at 29:1-9 (Ex. 1001).) With a blocker, only light produced by the plasma exits the chamber through the window. (See 943 Patent, 28:58-29:9 (Ex. 1001) (Eden Decl. 81 (Ex. 1006).) For example, Hiura describes the use of blockers in a laser sustained plasma light source system. (See, e.g., Hiura (Ex. 1004).) Hiura discloses an extreme ultraviolet light source that can be used with an integrated circuit lithography tool. (Hiura, 0002 (Ex. 1004).) Like Gärtner and the 943 patent, Hiura s light source uses a laser to supply energy to a plasma situated in a chamber. (See, e.g., Hiura, 0005 (Ex. 1004).) (Eden Decl. 82 (Ex. 1006).) Hiura also discloses the use of a stopper 150 (i.e., a blocker or beam dump), which prevents unabsorbed laser energy from exiting the chamber or damaging other components of the optical system. (Hiura, (Ex. 1004).) For example, Hiura states the blocker prevents the excitation laser from reaching the illumination optical system beyond the target. (Hiura 0020 (Ex. 1004).) Hiura further states that the stopper 150 is arranged to shield[] a propagation of the pulse laser beam 101 and absorb[] the pulse laser beam Thus the pulsed laser beam 101 does not irradiate or damage other components including the 40