IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`In re Patent of: Yasuhiro Omura
`U.S. Patent No.: 7,348,575 Attorney Docket: 24984-0056IP1
`Issue Date:
` March 25, 2008
`Appl. Serial No.: 11/266,288
`Filing Date:
` Nov. 4, 2005
`Title:
` PROJECTION OPTICAL SYSTEM, EXPOSURE
`
` APPARATUS, AND EXPOSURE METHOD
`
`Mail Stop Patent Board
`Patent Trial and Appeal Board
`U.S. Patent and Trademark Office
`P.O. Box 1450
`Alexandria, VA 22313-1450
`
`
`
`
`
`PETITION FOR INTER PARTES REVIEW OF CLAIMS 1-3, 8-12, 16-20,
`23-26, AND 29-33 OF UNITED STATES PATENT NO. 7,348,575
`PURSUANT TO 35 U.S.C. §§ 311–319, 37 C.F.R. § 42
`
`

`

`TABLE OF CONTENTS
`I.  MANDATORY NOTICES UNDER 37 C.F.R § 42.8 ....................................... 1 
`EVIDENCE ............................................................................................................... 2 
`II. 
`III.  REQUIREMENTS FOR IPR UNDER 37 C.F.R. §§ 42.104 ............................ 2 
`A.  Grounds for Standing Under 37 C.F.R. § 42.104(a)...................................... 3 
`B.  Identification of Challenge Under 37 C.F.R. § 42.104(b) ............................ 3 
`IV.  SUMMARY OF THE OMURA PATENT .......................................................... 6 
`A.  Technical Background .......................................................................................... 6 
`B.  The Alleged Invention of the Omura Patent ................................................. 11 
`C.  Claim Construction under 37 C.F.R. §§ 42.104(b)(3) ................................. 13 
`D.  Summary of the Prosecution History of the Omura Patent and Certain
`Related Applications ........................................................................................... 16 
`THE PRIOR ART .................................................................................................. 19 
`V. 
`A.  All of the limitations of claims 1-3, 10, 16-20, 24, 25, 29, 31-33 are
`disclosed in Takahashi, except the immersion limitation in claim 1 ....... 19 
`B.  Claim Chart for Takahashi Rejections .......................................................... 22 
`C.  All of the limitations of claims 1-3, 8-12, 16-20, 23-26, 29, 31-33 are
`disclosed in Terasawa, except the immersion limitation of claim 1 ........ 31 
`D.  Claim Chart for Terasawa Rejections ............................................................ 35 
`E.  The Immersion References ................................................................................ 44 
`Suwa teaches the immersion limitation that is missing from each of
`1. 
`Takahashi and Terasawa ............................................................................. 44 
`Switkes explains why immersion can increase numerical aperture
`and that immersion also increases depth of focus ................................. 45 
`3.  Ulrich demonstrates that a POSITA can implement immersion
`technology to increase NA ........................................................................... 47 
`Fukami teaches the immersion limitation to increase DOF for a
`catadioptric projection optical system having at least two mirrors
`and a single optical axis ............................................................................... 49 
`VI.  CLAIMS 1-3, 10, 16-20, 24, 25, 29, 31-33 ARE UNPATENTABLE AS
`OBVIOUS OVER TAKAHASHI IN VIEW OF THE IMMERSION
`REFERENCES ....................................................................................................... 50 
`VII.  CLAIMS 1-3, 8-12, 16-20, 23-26, 29, 31-33 ARE UNPATENTABLE AS
`OBVIOUS OVER TERASAWA IN VIEW OF THE IMMERSION
`REFERENCES ....................................................................................................... 55 
`
`4. 
`
`2. 
`
`

`

`VIII.  CLAIM 26 IS UNPATENTABLE AS OBVIOUS OVER TAKAHASHI IN
`VIEW OF THE IMMERSION REFERENCES, FURTHER IN VIEW OF
`TERASAWA AND SUENAGA ......................................................................... 56 
`IX.  CLAIM 30 IS UNPATENTABLE AS OBVIOUS OVER TAKAHASHI IN
`VIEW OF THE IMMERSION REFERENCES, FURTHER IN VIEW OF
`ASAI ........................................................................................................................ 57 
`CLAIM 30 IS UNPATENTABLE AS OBVIOUS OVER TERASAWA IN
`VIEW OF THE IMMERSION REFERENCES, FURTHER IN VIEW OF
`ASAI ........................................................................................................................ 59 
`XI.  CONCLUSION ...................................................................................................... 60 
`
`
`X. 
`
`

`

`Petition for IPR of US 7,348,575
`Page 1
`Carl Zeiss SMT GmbH (“Petitioner” or “Zeiss”) petitions for Inter Partes
`
`Review (“IPR”) under 35 U.S.C. §§ 311–319 and 37 C.F.R. § 42 of claims 1-3, 8-
`
`12, 16-20, 23-26, and 29-33 of U.S. Patent No. 7,348,575 (“the Omura Patent”),
`
`and asserts that there is a reasonable likelihood that it will prevail with respect to at
`
`5
`
`least one of the claims challenged in this petition (hereinafter the “Petition”).
`
`I. MANDATORY NOTICES UNDER 37 C.F.R § 42.8
`
`Carl Zeiss SMT GmbH is the real party-in-interest. 37 C.F.R. § 42.8(b)(1).
`
`The following applications claim benefit under Section 120 to the applica-
`
`tion that issued as the Omura Patent (“the Omura Application”): 11/513,160
`
`10
`
`(pending); 11/583,934 (issued as U.S. Patent No. 7,309,870); 11/583,916 (issued as
`
`U.S. Patent No. 7,312,463); 11/882,208 (abandoned); 12/379,415 (pending);
`
`12/884,332 (abandoned); and 13/275,760 (pending). Among these, U.S. Patent
`
`No. 7,309,870 (“the Omura ’870 Patent”), which issued from a continuation of the
`
`Omura Application, has been the subject of four interferences between Zeiss and
`
`15
`
`the assignee of the Omura Patent, Nikon Corporation (“Nikon”), specifically Inter-
`
`ference Nos. 105,678, 105,749, 105,753, and 105,834. (ZEISS 1001, cover page;
`
`ZEISS 1002, cover page; ZEISS 1003-ZEISS 1006.) Final judgment was entered
`
`against Nikon in each interference and the involved claims of the Omura ’870 Pa-
`
`tent were canceled. (ZEISS 1003, p. 2; ZEISS 1004, p. 2; ZEISS 1005, p. 2;
`
`20
`
`ZEISS 1006, p. 2.) In addition to the present Petition regarding the Omura Patent,
`
`
`
`

`

`Petition for IPR of US 7,348,575
`Page 2
`Zeiss is filing a second IPR petition on the same date as the present Petition to ad-
`
`dress claims 55-67 of the Omura Patent. Zeiss is not aware of any other proceed-
`
`ing involving the Omura Patent. 37 C.F.R. § 42.8(b)(2).
`
`Petitioner provides the following designation of counsel. 37 C.F.R. §
`
`5
`
`42.8(b)(3).
`
`LEAD COUNSEL
`Marc M. Wefers (Reg. No. 56,842)
`(wefers@fr.com)
`Fish & Richardson P.C.
`3200 RBC Plaza
`60 South Sixth Street
`Minneapolis, MN 55402
`T: 617-542-5070; F: 617-542-8906
`
`Please address all correspondence to the lead counsel at the address provided
`
`BACK-UP COUNSEL
`Chris C. Bowley (Reg. No. 55,016)
`(bowley@fr.com)
`Fish & Richardson P.C.
`3200 RBC Plaza
`60 South Sixth Street
`Minneapolis, MN 55402
`T: 212-765-5070; F: 212-258-2291
`
`above. Petitioner also consents to electronic service by email at:
`
`IPR24984-0056IP1@fr.com . 37 C.F.R. § 42.8(b)(4).
`
`10
`
`We authorize the United States Patent and Trademark Office (the “Office”)
`
`to charge Deposit Account No. 06-1050 for the fee set in 37 C.F.R. § 42.15(a) for
`
`this Petition for IPR, and further authorize payment for any additional fees to be
`
`charged to this Deposit Account.
`
`II. EVIDENCE
`
`15
`
`Appendix 1 lists the exhibits relied on in this Petition.
`
`III. REQUIREMENTS FOR IPR UNDER 37 C.F.R. §§ 42.104
`
`
`
`

`

`Petition for IPR of US 7,348,575
`Page 3
`
`A. Grounds for Standing Under 37 C.F.R. § 42.104(a)
`Zeiss certifies that the Omura Patent is eligible for IPR and that Zeiss is not
`
`barred or estopped from requesting IPR.
`
`Identification of Challenge Under 37 C.F.R. § 42.104(b)
`
`B.
`Zeiss requests IPR of claims 1-3, 8-12, 16-20, 23-26, 29-33 of the Omura
`
`5
`
`Patent (the “Challenged Claims”) based on the prior art and grounds set forth be-
`
`low, and requests that the Office finds these claims to be unpatentable.
`
`Prior Art Reference
`
`1. PCT Patent Publication
`
`WO 02/035273 (“Takahashi PCT”)
`2. US Patent Application Publication No.
`US 2002/0024741 A1 (“Terasawa”)
`3. US Patent No. 5,825,043 (“Suwa”)
`
`4. M. Switkes and M. Rothschild,
`“Resolution Enhancement of 157 nm Lithogra-
`phy by Liquid Immersion,” Proc. SPIE Vol.
`4691, pp. 460-465 (2002) (“Switkes”)
`5. Willi Ulrich et al., “The Development of Diop-
`tric Projection Lenses for DUV Lithography,”
`Proc. SPIE Vol. 4832, pp. 158-169 (2002)
`(“Ulrich”)
`6. PCT Patent Publication
`WO 99/49504 (“Fukami JP”)
`7. European Patent Application Publication No.
`EP 1 069 448 B1 (“Suenaga”)
`
`Publication Date
`Published May 2, 2002
`(ZEISS 1007)
`Published Feb. 28, 2002
`(ZEISS 1008)
`Patented Oct. 20, 1998
`(ZEISS 1009)
`Published in 2002
`(ZEISS 1010)
`
`Published in 2002
`(ZEISS 1011)
`
`Published Sept. 30, 1999
`(ZEISS 1012)
`Published March 19,
`2003
`(ZEISS 1027)
`Published Dec. 1993
`(ZEISS 1013)
`
`8. Satori Asai et al., “Resolution Limit for Optical
`Lithography Using Polarized Light Illumina-
`tion,” Jpn. J. Appl. Phys. Vol. 32, pp. 5863-
`5866 (1993) (“Asai”)
`
`Each of the references listed above was patented or published more than 1-
`
`
`
`

`

`Petition for IPR of US 7,348,575
`Page 4
`year before May 6, 2004, which is the earliest possible United States filing date to
`
`which the Omura Patent can claim benefit. (ZEISS 1001, cover page, (63).) Ac-
`
`cordingly, each reference qualifies as prior art under Section 102(b). Takahashi
`
`PCT was published in Japanese and republished in English by the European Patent
`
`5
`
`Office as EP 1336 887 A1 (“Takahashi”) on August 20, 2003. (ZEISS 1014, cover
`
`page, (87); ZEISS 1026, material fact 131, admitted.) Accordingly, in what fol-
`
`lows we refer to this English publication of the Takahashi PCT when citing to the
`
`Takahashi prior art. Fukami JP was also published in Japanese, and in what fol-
`
`lows we refer to a certified English translation of Fukami JP (“Fukami”) when cit-
`
`10
`
`ing to the Fukami prior art. (ZEISS 1015, p. 1.)
`
`The proposed rejections are set forth in the table below. As explained in de-
`
`tail herein, Takahashi and Terasawa each disclose “dry” catadioptric projection op-
`
`tical systems for microlithography, whereas Suwa, Switkes, Ulrich, and Fukami
`
`(collectively “the Immersion References”) each disclose introducing an immersion
`
`15
`
`liquid between the last lens element of a projection optical system and the wafer
`
`onto which the projection optical system projects an image, to thereby modify the
`
`“dry” system to an “immersed” system.
`
`The two “dry” primary references, Takahashi and Terasawa, are not redun-
`
`dant. For example, Takahashi (combined with Suwa) has already been relied on by
`
`20
`
`the Office to reject substantially similar claims in a continuation application of the
`
`
`
`

`

`Petition for IPR of US 7,348,575
`Page 5
`Omura Patent. Also, Takahashi provides an express figure for the effective imag-
`
`ing area claimed in independent claim 1 (e.g., “effective exposure area ER” in
`
`Figs. 1, 3, and 15) and express disclosure relevant to certain dependent claims
`
`(e.g., that an exposed wafer is “photosensitive”). On the other hand, Terasawa
`
`5
`
`provides additional disclosure not found in Takahashi that is relevant to certain
`
`other dependent claims (e.g., claims to only two mirrors). Finally, because Zeiss
`
`cannot know what rebuttal arguments Nikon will make, we respectfully submit that
`
`using two primary references is not contrary to securing “the just, speedy, and in-
`
`expensive resolution” of this proceeding required by 37 C.F.R. § 42.1(b).
`
`10
`
`The four Immersion References are being applied collectively in each of the
`
`proposed rejections. While each Immersion Reference independently discloses the
`
`immersion limitation missing from Takahashi and Terasawa, they provide inter-
`
`related and complementary teachings to collectively reinforce why it would have
`
`been obvious to modify a dry system to include the immersion limitation. KSR In-
`
`15
`
`ternational Co. v. Teleflex Inc. (KSR), 550 U.S. 398, 401 (2007) (an obviousness
`
`analysis can look to interrelated teachings in the prior art.) For example, Suwa was
`
`previously raised by the Office (and not disputed by Nikon) to demonstrate the ob-
`
`viousness of the immersion limitation. Ulrich describes in greater detail how to
`
`achieve the benefits of immersion described in Suwa (to increase numerical aper-
`
`20
`
`ture). In addition to increasing numerical aperture, Switkes teaches yet another
`
`
`
`

`

`Petition for IPR of US 7,348,575
`Page 6
`reason to use immersion (to increase depth of focus), and Fukami teaches applica-
`
`tion of immersion for a specific system that is relevant here (i.e., a system with at
`
`least two mirrors and a single optical axis).
`
`The remaining prior art references address certain dependent claims.
`
`Ground Omura Patent Claims
`Ground 1 1-3, 10, 16-20, 24, 25,
`29, 31-33
`Ground 2 1-3, 8-12, 16-20, 23-
`26, 29, 31-33
`Ground 3 26
`
`Proposed Rejection
`Obvious under § 103(a) by Takahashi in
`view of the Immersion References
`Obvious under § 103(a) by Terasawa in
`view of the Immersion References
`Obvious under § 103(a) by Takahashi in
`view of the Immersion References, fur-
`ther in view of Terasawa and Suenaga
`Obvious under § 103(a) by Takahashi in
`view of the Immersion References, fur-
`ther in view of Asai
`Obvious under § 103(a) by Terasawa in
`view of the Immersion References, fur-
`ther in view of Asai
`In the sections that follow we explain how the Challenged Claims are to be
`
`Ground 4 30
`
`Ground 5 30
`
`5
`
`construed, and why they are unpatentable under Grounds 1-5, including where
`
`each claim limitation is found in the Prior Art References listed above. Additional
`
`explanation and support for each ground of rejection is set forth in the Expert Dec-
`
`laration of Richard C. Juergens (ZEISS 1016, ¶¶ 1-24).
`
`10
`
`IV. SUMMARY OF THE OMURA PATENT
`
`A. Technical Background
`The Omura Patent relates to catadioptric projection optical systems for use
`
`in projection exposure apparatus used in the production of semiconductor devices.
`
`
`
`

`

`Petition for IPR of US 7,348,575
`Page 7
`(ZEISS 1001, 1:18-23.) During operation, a projection exposure apparatus projects
`
`an image of a reticle pattern onto a “photosensitive substrate,” such as a wafer
`
`coated with a photoresist. In this field, the terms “reticle” and “mask” are used in-
`
`terchangeably. Further processing of the exposed coating, such as developing the
`
`5
`
`exposed coating and depositing material over the developed coating or etching ma-
`
`terial beneath the developed coating, allows one to build up the tiny complex com-
`
`ponents forming integrated circuits. The projection exposure apparatus generally
`
`includes an illumination system to illuminate the reticle pattern with light, the pro-
`
`jection optical system to project an image of the illuminated reticle pattern onto the
`
`10
`
`photosensitive substrate, and a substrate positioning system to position the photo-
`
`sensitive substrate relative to the image. (ZEISS 1016, ¶¶ 25-30; see e.g., ZEISS
`
`1014, [0033]-[0035], [0051]-[0054], [0239], [0240]; ZEISS 1001, 1:29-30, 6:23,
`
`17:14; 56:33-45; ZEISS 1008, [0274].)
`
`A projection optical system typically includes multiple imaging elements.
`
`15
`
`Each imaging element can be a “transmitting member,” such as a lens, or a “re-
`
`flecting member,” such as a curved mirror. Each imaging optical element bends
`
`lights rays to thereby focus or defocus light to a degree measured by its “power”
`
`(also referred to as “optical power,” “refracting power,” or “refractive power”).
`
`Each surface of a lens bends light rays based on its curvature and the refractive in-
`
`20
`
`dex of the lens relative to the lower refractive index of the surrounding medium
`
`
`
`

`

`Petition for IPR of US 7,348,575
`Page 8
`(e.g., air or water). (ZEISS 1016, ¶¶ 31, 43-52; see also ZEISS 1017.) For exam-
`
`ple, a convex lens surface will have positive power and focus light, whereas a con-
`
`cave lens surface will have negative power and defocus light. A mirror having a
`
`convex surface defocuses light it reflects and therefore has negative power, where-
`
`5
`
`as a mirror having a concave surface focuses light it reflects and therefore has posi-
`
`tive refractive power. The power of a collection of imaging elements is deter-
`
`mined by the degree to which the collection of elements as a whole focuses or de-
`
`focuses light. (ZEISS 1016, ¶¶ 46-52.)
`
`A projection optical system whose imaging elements are all lenses is a “di-
`
`10
`
`optric” optical system. A projection optical system whose imaging elements are all
`
`mirrors is a “catoptric” optical system. A projection optical system whose imaging
`
`elements includes at least one lens and at least one mirror is a “catadioptric” opti-
`
`cal system. Accordingly, a “catadioptric projection optical system” is a projection
`
`optical system whose imaging elements include at least one lens and at least one
`
`15
`
`mirror. (ZEISS 1016, ¶¶ 62, 63; see also ZEISS 1018, pp. 19-23.)
`
`The way a projection optical system projects an image from a first surface to
`
`a second surface can be depicted by tracing the paths of light rays emerging from
`
`the first surface through the optical elements that comprise the projection optical
`
`system onto the second surface. Specifically, multiple light rays emerging from
`
`20
`
`each of multiple points on the first surface (defining the “object”) are recombined
`
`
`
`

`

`Petition for IPR of US 7,348,575
`Page 9
`at each of corresponding points on the second surface (defining the “image”). In
`
`addition to the final image, a projection optical system can also include one or
`
`more intermediate images, which are intermediate locations between the first and
`
`second surfaces where multiple light rays emerging from each of multiple points
`
`5
`
`on the first surface (defining the “object”) are recombined at each of corresponding
`
`points. FIGS. 5, 7, 9, 10, and 14-16 in the Omura Patent are examples of such ray
`
`diagrams, with FIGS. 5, 7, 9, and 10 having one intermediate image and FIGS. 14-
`
`16 having two intermediate images. (ZEISS 1016, ¶¶ 31-37.)
`
`An aperture stop is the element in the projection optical system that limits
`
`10
`
`range of angles over which light rays projected from the first surface can pass
`
`through the optical system to reach the second surface. A pupil is the location of
`
`this aperture stop, or any image of this aperture stop. For example, entrance and
`
`exit pupils are images of the aperture stop as seen from the first and second surface
`
`sides, respectively. (ZEISS 1016, ¶¶ 39-40; see also ZEISS 1019, pp. 171-173.)
`
`15
`
`Each optical surface in the projection optical system typically corresponds to
`
`a mathematical surface that is rotationally symmetric about an axis. This axis de-
`
`fines the “optical axis” for the optical surface. The optical axis for an optical sys-
`
`tem comprising multiple surfaces is defined by the sequence of optical axes for the
`
`respective surfaces. In some cases, the optical axes for all of the surfaces that de-
`
`20
`
`fine the optical system are the same. This is the case for all of the embodiments of
`
`
`
`

`

`Petition for IPR of US 7,348,575
`Page 10
`the Omura Patent (i.e., the embodiments of FIGS. 5, 7, 9, 10, and 14-16), each of
`
`which has a single optical axis AX. Such designs are sometimes referred to as “in-
`
`line” designs. (ZEISS 1016, ¶ 55; ZEISS 1020; ZEISS 1001, 16:3-17.)
`
`During operation of a projection exposure apparatus, the illumination system
`
`5
`
`illuminates the portion of the reticle that is intended to be reproduced on the wafer.
`
`The area of the wafer on which the projection optical system forms the image of
`
`this illuminated portion defines a corresponding effective imaging area (or equiva-
`
`lently, an “effective exposure region”) for the projection optical system. In some
`
`cases, such as that for the embodiments of the projection optical system in the
`
`10
`
`Omura Patent, the projection optical system is designed so that the effective imag-
`
`ing area on the wafer (W) excludes the optical axis AX. This can be referred to as
`
`an “off-axis” projection optical system. (ZEISS 1016, ¶ 56-58; ZEISS 1018, p. 20;
`
`ZEISS 1001, 9:35-50, 16:3-10, 19:65-20:23; ZEISS 1027, [0033].)
`
`The resolving power of a projection optical system varies inversely with the
`
`15
`
`size of smallest possible feature in the image produced by the projection optical
`
`system (“resolution”), which is expressed by the relationship kλ/NA, where λ is the
`
`operational wavelength of the system, NA refers to the image-side numerical aper-
`
`ture of the system (hereinafter “NA”), and k is a process co-efficient. NA equals
`
`n·sin θ, where n is a refractive index of a medium between the projection optical
`
`20
`
`system and the image plane and θ is the maximum angle of incidence of the light
`
`
`
`

`

`Petition for IPR of US 7,348,575
`Page 11
`rays forming the image on the wafer. Accordingly, to improve resolution, one can
`
`reduce the wavelength λ, and/or increase NA. To increase NA, one can increase the
`
`maximum angle θ and/or increase the refractive index of the medium between the
`
`projection optical system and the image plane. (ZEISS 1016, ¶¶ 70-74; ZEISS
`
`5
`
`1001, 1:37-48; ZEISS 1008, [0002]; ZEISS 1014, [0003]; ZEISS 1011, 158.)
`
`The Alleged Invention of the Omura Patent
`
`B.
`The Omura Patent is directed to a “relatively compact projection optical sys-
`
`tem having excellent imaging performance” including “being capable of securing a
`
`large effective image-side numerical aperture.” (ZEISS 1001, 2:3-10.) The Omura
`
`10
`
`Patent concedes that there is a practical limit to increasing the maximum angle of
`
`incidence in order to increase NA, and goes on to explain that:
`
`For this reason, there is the known technology of increasing the nu-
`merical aperture NA by filling a medium like a liquid with a high re-
`fractive index in the optical path between the projection optical sys-
`tem and the image plane. (ZEISS 1001, 1:55-58.)
`This known technology is called “immersion” (and the liquid is known as an “im-
`
`15
`
`mersion liquid”) and has been known for over a century. (ZEISS 1016, ¶¶ 71-74,
`
`200, 201, 206-212, 215-218; ZEISS 1011, p. 166.) The Omura Patent contends
`
`that the application of immersion technology to conventional dioptric projection
`
`20
`
`optical systems caused certain disadvantages. Specifically, when the imaging ele-
`
`ments of the projection optical system consists only of lenses (and is therefore “di-
`
`
`
`

`

`Petition for IPR of US 7,348,575
`Page 12
`optric”), it became difficult to achieve both a large NA and correct for field curva-
`
`ture. (ZEISS 1001, 1:59-67, 5:34-37.)
`
`Accordingly, the Omura Patent describes a “catadioptric” projection optical
`
`system that uses immersion technology. The catadioptric projection optical system
`
`5
`
`has at least two mirrors and a final lens that separates the immersion liquid from
`
`the remaining elements of the projection optical system. (ZEISS 1001, 2:38-50.)
`
`The Omura Patent explains that the combination of mirrors and lenses in the cata-
`
`dioptric system can be used to correct for field curvature by satisfying the Petzval
`
`condition. (ZEISS 1001, 5:45-51, 6:45-49.) The Omura Patent also describes this
`
`10
`
`catadioptric projection optical system having a single optical axis for all of its
`
`lenses and mirrors, which, according to the Omura Patent, reduces manufacturing
`
`difficulties and simplifies performance adjustments. (ZEISS 1001, 5:52-59, and
`
`16:3-17). The detailed embodiment of FIG. 5 in the Omura Patent is exemplary of
`
`such features. (ZEISS 1016, ¶¶ 31-36, 44, 45, 50, 51, 53-55, 64-66.)
`
`15
`
`Independent claim 1 of the Omura Patent, the only independent claim sub-
`
`ject to the present Petition, recites (sub-headings added) 1:
`
`1 The words catadioptric and larger appear to be misspelt as “catadioptirc” and “la-
`
`ger” in subparts [1a] and [1d] of claim 1 of the Omura Patent, respectively. For the
`
`purpose of this Petition, we will presume the correct spelling. (ZEISS 1001, claim
`
`1.)
`
`
`
`

`

`Petition for IPR of US 7,348,575
`Page 13
`[1a] A catadioptirc [sic] projection optical system, which forms a reduced
`image of a first surface on a second surface, comprising:
`[1b] at least two reflecting mirrors; and
`[1c] a boundary lens whose surface on the first surface side has a positive
`refractive power
`[1d] wherein where a refractive index of an atmosphere in an optical path
`of the projection optical system is 1, an optical path between the boundary
`lens and the second surface is filled with a medium having a refractive index
`lager [sic] than 1.1,
`[1e] wherein every transmitting member and every reflecting member with
`a refractive power constituting the projection optical system are arranged
`along a single optical axis; and
`[1f]
`the projection optical system having an effective imaging area of a
`predetermined shape not including said optical axis.
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`5
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`10
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`15
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`
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`C. Claim Construction under 37 C.F.R. §§ 42.104(b)(3)
`A claim subject to IPR is given its “broadest reasonable construction in light
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`of the specification of the patent in which it appears.” 37 C.F.R. § 42.100(b). This
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`means that the words of the claim are given their plain meaning unless that mean-
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`ing is inconsistent with the specification. In re Zletz, 893 F.2d 319, 321 (Fed. Cir.
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`20
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`1989). Unless otherwise addressed below, Zeiss submits that the words in the
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`Challenged Claims take on this plain meaning, such as set forth in the Technical
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`Background section, supra.
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`Based on its express language, the catadioptric projection optical system of
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`Petition for IPR of US 7,348,575
`Page 14
`claim 1 of the Omura Patent includes at least two reflecting mirrors (limitation
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`[1b]) and the “boundary” lens whose surface on the first surface side has a positive
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`refractive power (limitation [1c]). The claimed lens is a boundary lens because of
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`the “immersion limitation” that follows (limitation [1d]). Specifically, the claimed
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`5
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`lens is at the boundary between the “atmosphere in an optical path of the projection
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`optical system [whose refractive index] is 1,” and the “medium having a refractive
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`index larger than 1.1”, which is “between the boundary lens and the second sur-
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`face.” In other words, when an immersion liquid is introduced between the last
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`lens element of the projection optical system and the wafer (as in limitation [1d]),
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`the last lens element becomes a “boundary lens.” (ZEISS 1016, ¶¶ 84-91; ZEISS
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`1001, 20:45-49, FIG. 3.) We also construe “a refractive index … is 1” in limitation
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`[1c] to mean equal to 1 to within at least the first decimal place. This is consistent
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`with the express use of the first decimal place for the claimed refractive index larg-
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`er than 1.1, and the examples in the specification of the atmosphere in the projec-
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`15
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`tion optical system being an inert gas, such as helium or nitrogen, which have re-
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`fractive indices close to 1, but not exactly equal to 1. (ZEISS 1016, ¶¶ 86-92;
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`ZEISS 1001, 20:24-44; ZEISS 1024, p. 2.)
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`The two remaining limitations of claim 1 (limitations [1e] and [1f]) indicate
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`that the claimed projection optical system has a single optical axis and an off-axis
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`20
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`effective imaging area, respectively. Specifically, with respect to limitation [1e],
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`

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`Petition for IPR of US 7,348,575
`Page 15
`all of the lenses and mirrors with optical power share a single optical axis and are
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`arranged along this single optical axis. (ZEISS 1016, ¶ 55; ZEISS 1001, 5:52-59,
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`and 16:3-17). With respect to limitation [1f], the “effective imaging area,” has a
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`shape “predetermined” by the portion of the reticle that is illuminated by the illu-
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`5
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`mination system and projected through the projection optical system to form an
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`image, and this image area does “not includ[e] the optical axis.” The Omura Pa-
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`tent also interchangeably uses the expressions “effective exposure area” and “ef-
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`fective exposure region ER” to refer to the claimed “effective imaging area.”
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`(ZEISS 1016, ¶¶ 56-61; ZEISS 1001, 9:35-50, 16:3-10, 19:65-20:23.)
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`10
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`Below we address certain issues in the dependent claims.
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`Dependent claim 18 refers to “every effective imaging area of the projection
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`optical system” (emphasis added), whereas claim 1 recites “the projection optical
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`system having an effective imaging area.” For the purpose of this Petition, we con-
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`strue “every effective imaging area” to mean the effective imaging area formed on
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`15
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`the second surface as the final image, as well as effective imaging areas corre-
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`sponding to any intermediate images. (ZEISS 1016, ¶ 93.)
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`Dependent claim 25 depends from claims 1 and 10 and recites “the second
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`imaging optical system,” but no such second imaging optical system is recited in
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`claims 1 and 10. For the purpose of this Petition, we construe “the second imaging
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`20
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`optical system” in claim 25 to refer back to the “second lens unit” recited in claim
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`

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`Petition for IPR of US 7,348,575
`Page 16
`10. (ZEISS 1016, ¶ 94.)
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`D.
`Summary of the Prosecution History of the
`Omura Patent and Certain Related Applications
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`The Omura Application was allowed in a first action allowance. Takahashi,
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`5
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`and Terasawa were each before the Examiner, but there was no substantive discus-
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`sion of either reference during prosecution. (ZEISS 1021, pp. 2, 6-9.)
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`As explained in detailed infra, each of Takahashi and Terasawa disclose all
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`of the limitations of independent claim 1, except the immersion limitation directed
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`to the medium between the boundary lens and the second surface having a refrac-
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`10
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`tive index greater than 1.1 (i.e., limitation [1d] in claim 1). Specifically, they each
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`disclose a catadioptric projection objective having a single optical axis and an off-
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`axis effective imaging area. Evidently, the Examiner believed that the immersion
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`limitation patentably distinguished such references. (ZEISS 1021, pp. 7-8.)
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`But, the Examiner in a subsequent continuation application of the Omura
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`15
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`Application, application no. 11/513,160 (“the Omura Continuation Application”),
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`found to the contrary, concluding that modifying the Takahashi catadioptric projec-
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`tion objective to include immersion technology would have been obvious. Specifi-
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`cally, in the Office Action dated July 14, 2008, the Examiner rejected certain
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`claims as obvious based on Takahashi in view of Suwa. (ZEISS 1022, pp. 16-17,
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`20
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`62-63.) The Examiner determined that Takahashi disclosed a catadioptric projec-
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`tion objective with several limitations similar to those claimed in the Omura Pa-
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`
`
`

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`Petition for IPR of US 7,348,575
`Page 17
`tent, and that:
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`5
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`10
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`Takahashi discloses the claimed invention except for wherein the third
`objective part contacts an immersion liquid to image the second in-
`termediate image through the immersion liquid onto the image plane.
`Suwa teaches that it is very well known to use an immersion liquid to
`image the [sic] through the immersion liquid onto the image plane in a
`catadioptric projection system (e.g., fig. 8A) to improve resolution
`(column 3, lines 24-33). It would have been obvious to one having or-
`dinary skill in the art at the time the invention was made to add an
`immersion liquid to projection end side (i.e., the third objective part)
`of Takahashi as taught by Suwa to increase the effective numerical
`aperture and improve the resolution of the image (Suwa, column 3,
`lines 24-33). (ZEISS 1022, p. 63.)
`Tellingly, in response, Nikon did not dispute the obviousness of implementing an
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`15
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`immersion liquid into the prior art Takahashi catadioptric projection objective,
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`choosing instead in an Amendment dated August 14, 2009 to narrow the rejected
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`claims to include further limitations that allegedly distinguished Takahashi.
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`(ZEISS 1022, pp. 16-17, 35.)
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`Similarly, Nikon did not provide any evidence to support the non-
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`20
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`obviousness of modifying a prior art catadioptric projection to implement immer-
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`sion technology when judgment was entered against Omura during Interference
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`No. 105,753 involving the Omura ’870 Patent. (ZEISS 1005, p.2; ZEISS 1023,
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`9:7-11:7.) The relevant issue was whether the limitation in claim 20 of the Omura
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`Petitio