Ulllted States Patent [19]
`Takahashi
`
`US005808805A
`[11] Patent Number:
`[45] Date of Patent:
`
`5,808,805
`*Sep. 15, 1998
`
`[54] EXPOSURE APPARATUS HAVING
`CATADIOPTRIC PROJECTION OPTICAL
`
`8/1993 Chiu et al. ............................ .. 359/727
`5,241,423
`5,253,110 10/1993 Ichihara et al. .
`. 359/619
`
`SYSTEM
`
`_
`-
`-
`[75] Inventor‘ gplggwakl Takahashl’ Yokohama’
`
`.
`.
`,
`[73] AsslgneeZ Nlkon Corporatlom Japan
`
`[ * ]
`
`Notice:
`
`The term of this patent shall not extend
`b
`dth
`'t' dt fPt.N.
`5633066 6 explra m a e O
`a
`0
`
`5,333,035
`
`. . . . . .. 355/77
`
`7/1994 Shiraishi . . . . . . . .
`_
`.. 250/2012
`5,365,051 11/1994 SuZukletal.
`5,379,091
`1/1995 Tanitsu et al. .......................... .. 355/67
`5,402,267
`3/1995 Putter et al. .......................... .. 359/727
`5,537,260
`7/1996 Williamson
`..
`5,583,696 121996 Tak h h'
`..
`5,636,066
`6/1997 Takghgzhl ............................. .. 359/726
`
`OTHER PUBLICATIONS
`
`US. application NO. 08/212,639, Takahashi, ?led Mar. 10,
`
`’
`
`’
`
`'
`
`1994.
`
`[21] Appl. NO.Z 429,970
`
`[22] Filed;
`
`Apt 27, 1995
`
`[30]
`
`Foreign Application Priority Data
`
`Apr. 28, 1994
`
`[JP]
`
`Japan .................................. .. 6090837
`
`l. ?ldS .1
`N.08299305 Ot t
`t'
`l'
`US.
`1994 app lea 10H 0
`/
`’
`’
`a e a ’
`6
`6p ’
`
`US. application No. 08/255,927, Nakashima et al., ?led Jun.
`7, 1994.
`US. application NO. 08/260,398, Nishi et al., ?led Jun. 14,
`1994.
`
`Int. clf ..................................................... .. G02B 3/00
`[51]
`[52] US. Cl. ........................... .. 359/651; 355/53, 359/631
`[58] Field Of Search ................................... .. 359/631, 649,
`359/650, 651, 726, 727; 355/53
`
`Primary EXami'?”—Nabi1Hindi_
`2281mmZXMZW’FWEMMFgegd d LLP
`Omey’ g6”) 0’ "m enme
`m0“ S
`[57]
`ABSTRACT
`
`[56]
`
`References Cited
`
`U'S' PATENT DOCUMENTS
`1/1985 Konno et al. ......................... .. 362/268
`4,497,015
`5/1987 Shimizu et a], _
`353/101
`4,666,273
`8/1987 Hirose ............ ..
`359/727
`4,685,777
`359/727
`4,701,035 10/1987 Hirose ---- -
`4,779,966 10/1988 Ff{ec_lman
`350/442
`479537960
`9/1990 W?hamson "
`359/727
`Z: 2}‘ "
`"
`' "
`.
`.
`3/1993 Nlshl ........................ .. 355/53
`5/1993 Williamson et al.
`359/727
`6/1993 Ichihara et al. ....................... .. 359/487
`
`’
`’
`5,194,893
`5,212,593
`5,220,454
`
`To use a beam splitting optical system smaller than the
`conventional beam splitters and to set a longer optical path
`betWeen a concave, re?ective mirror and an image plane. A
`light beam from an Object Surface travels through a ?rst
`converging group to enter a beam splitter, and a light beam
`re?ected by the beam splitter is re?ected by a concave,
`re?ective mirror to form an image of patterns on the object
`surface inside the concave, re?ective mirror. A light beam
`from the image of the patterns passes through the beam
`splitter and thereafter forms an image of the patterns through
`a third converging group on an image plane.
`
`25 Claims, 13 Drawing Sheets
`
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`
`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 1
`
`

`

`U.S. Patent
`
`Sep. 15,1998
`
`Sheet 1 0f 13
`
`5,808,805
`
`Fig_l
`
`/
`ILLUMINATION
`OPTICAL SYSTEM
`
`ALIGNMENT
`LIGHT SOURCE:\J> OPTICAL SYSTEM
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`EXCHANGE
`SYSTEM
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`SYSTEM
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`MAIN
`CONTROL
`SECTION
`
`/
`
`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 2
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`

`

`U.S. Patent
`
`Sep. 15,1998
`
`Sheet 2 0f 13
`
`5,808,805
`
`l
`
`I
`I
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`
`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 3
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`

`

`US. Patent
`
`Sep. 15,1998
`
`Sheet 3 0f 13
`
`5,808,805
`
`
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`CARL ZEISS v. NIKON
`|PR2013-00362
`
`Ex. 2010, p. 4
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`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 4
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`

`

`US. Patent
`
`Sep.15,1998
`
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`CARL ZEISS V. NIKON
`|PR2013-00362
`
`EX. 2010, p. 5
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`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 5
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`

`

`US. Patent
`
`Sep. 15, 1998
`
`Sheet 5 0f 13
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`5,808,805
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`CARL ZEISS V. NIKON
`|PR2013-00362
`
`EX. 2010, p. 6
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`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 6
`
`
`

`

`U.S. Patent
`
`Sep. 15,1998
`
`Sheet 6 0f 13
`
`5,808,805
`
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`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 7
`
`

`

`U.S. Patent
`US. Patent
`
`Sep. 15,1998
`Sep. 15, 1998
`
`Sheet 7 0f 13
`Sheet 7 0f 13
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`5,808,805
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`CARL ZEISS V. NIKON
`|PR2013-00362
`
`EX. 2010, p. 8
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`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 8
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`

`

`U.S. Patent
`
`Sep. 15,1998
`
`Sheet 8 0f 13
`
`5,808,805
`
`Fig . l7
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`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 9
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`

`

`U.S. Patent
`
`Sep. 15,1998
`
`Sheet 9 0f 13
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`5,808,805
`
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`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 10
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`

`

`US. Patent
`
`Sep. 15, 1998
`
`Sheet 10 0f 13
`
`5,808,805
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`CARL ZEISS V. NIKON
`|PR2013-00362
`
`EX. 2010, p. 11
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`IPR2013-00362
`Ex. 2010, p. 11
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`
`

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`U.S. Patent
`
`Sep. 15,1998
`
`Sheet 11 0f 13
`
`5,808,805
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`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 12
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`

`

`US. Patent
`
`Sep. 15, 1998
`
`Sheet 12 0f 13
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`5,808,805
`
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`CARL ZEISS V. NIKON
`|PR2013-00362
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`Ex.2010,p.13
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`IPR2013-00362
`Ex. 2010, p. 13
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`U.S. Patent
`
`Sep. 15,1998
`
`Sheet 13 0f 13
`
`5,808,805
`
`Fig.3l
`
`ILLUMINATION
`OPTICAL SYSTEM \,|
`
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`OPTICAL SYSTEM
`
`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 14
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`

`

`1
`EXPOSURE APPARATUS HAVING
`CATADIOPTRIC PROJECTION OPTICAL
`SYSTEM
`
`5,808,805
`
`2
`alignment optical system 110 for adjusting a relative posi
`tions betWeen the mask R and the Wafer W, and the mask R
`is disposed on a reticle stage 2 Which is movable in parallel
`With respect to the main surface of the Wafer stage 3. The
`catadioptric projection optical system has a space permitting
`an aperture stop 6 to be set therein. The sensitive substrate
`W comprises a Wafer 8 such as a silicon Wafer or a glass
`plate, etc., and a photosensitive material 7 such as a photo
`resist or the like coating a surface of the Wafer 8.
`In particular, as shoWn in FIGS. 2, 17, and 31, the
`catadioptric projection optical system comprises a ?rst
`image-forming optical system (G1(f1),G2(f2)) for forming an
`intermediate image 11 of the pattern of the mask R, and a
`second image-forming optical system (G3(f3)) for forming
`an image of the intermediate image 11 on the substrate W.
`The ?rst image-forming optical system has a ?rst group
`G1(f1) With a positive refractive poWer, comprising a refrac
`tive lens component, for converging a light beam from the
`pattern of the mask R, a second group G2(f2) With a positive
`refractive poWer, comprising a concave, re?ective mirror M2
`for re?ecting a light beam from the ?rst group G1(f1), for
`forming the intermediate image 11 of the pattern of the mask
`R, and a beam splitting optical system 10PBS (including
`10A, 10B, and 10C) or 12 as a beam splitting optical system
`for changing a traveling direction of one of a light beam
`from the ?rst group G1(f1) and a re?ected light from the
`concave, re?ective mirror M2, and thereby a part of the light
`beam converged by the second group G2(f2) is guided to the
`second image-forming optical system G3(f3). The parameter
`f1 means as a focus length of the ?rst group G1 in the ?rst
`image-forming optical system, the parameter f2 means as a
`focus length of the second group G2 in the ?rst image
`forming optical system, and the parameter f3 means as a
`focus length of a lens group G3 in the second image-forming
`optical system.
`The catadioptric projection optical system in FIG. 2 is an
`optical system for projecting an image of a pattern of a ?rst
`surface P1 onto a second surface P2, Which has a ?rst
`image-forming optical system (G1, G2) for forming an
`intermediate image 11 of the pattern of the ?rst surface P1
`and a second image-forming optical system (G3) for forming
`an image of the intermediate image 11 on the second surface
`P2.
`The ?rst image-forming optical system comprises a ?rst
`group G1(f1) of a positive refractive poWer, comprising a
`refractive lens component, for converging a light beam from
`the pattern of the ?rst surface P1, a prism type beam splitter
`10PBS for separating a part of a light beam from the ?rst
`group by a beam splitter surface 10PBSa arranged obliquely
`to the optical axis AXl of the ?rst group, and a second group
`G2(f2) With a positive refractive poWer, comprising a
`concave, re?ective mirror M2 for re?ecting the light beam
`separated by the prism type beam splitter 10PBS, for form
`ing the intermediate image 11 of the pattern near the prism
`type beam splitter 10PBS, in Which a part of the light beam
`converged by the second group G2(f2) is separated by the
`prism type beam splitter 10PBS to be guided to the second
`image-forming optical system G3(f3). The prism type beam
`splitter is disposed on the optical axis AXl of the ?rst group
`G1(f1) and provided betWeen the concave, re?ective mirror
`M2 and the second image-forming optical system.
`In this case, it is desirable that the intermediate image 11
`of the pattern be formed inside the prism type beam splitter
`10PBS. Also, as shoWn in FIG. 2, it is desired that in order
`to prevent generation of ?are due to repetitive re?ections
`betWeen the concave, re?ective mirror M2 and the second
`surface P2, a polariZing beam splitter be used as the beam
`
`BACKGROUND OF THE INVENTION
`
`1. Field of the Invention
`The present invention relates to a catadioptric projection
`optical system suitable for applications to projection optical
`systems for 1:1 or demagnifying projection in projection
`exposure apparatus such as steppers used in fabricating, for
`example, semiconductor devices or liquid crystal display
`devices, etc., by photolithography process. More
`particularly, the invention relates to a catadioptric projection
`optical system of a magni?cation of 1A1 to 1/5 With a resolution
`of submicron order in the ultraviolet Wavelength region,
`using a re?ecting system as an element in the optical system.
`2. Related Background Art
`In fabricating semiconductor devices or liquid crystal
`display devices, etc. by photolithography process, the pro
`jection exposure apparatus is used for demagnifying through
`a projection optical system a pattern image on a reticle (or
`photomask, etc.) for example at a ratio of about 1A to 1/5 to
`effect exposure of the image on a Wafer (or glass plate, etc.)
`coated With a photoresist or the like.
`The projection exposure apparatus With a catadioptric
`projection optical system is disclosed, for example, in J apa
`nese Laid-open Patent Application No. 2-66510, Japanese
`Laid-open Patent Application No. 3-282527, US. Pat.
`(USP) No. 5,089,913, Japanese Laid-open Patent Applica
`tion No. 5-72478, or US. Pat. No. 5,052,763, No. 4,779,966,
`No. 4,65,77, No. 4,701,035.
`
`10
`
`15
`
`20
`
`25
`
`30
`
`SUMMARY OF THE INVENTION
`
`An object of the present invention is to provide an
`exposure apparatus having a catadioptric projection optical
`system Which can use a beam splitting optical system
`smaller than the conventional polariZing beam splitter and
`Which is excellent in image-forming performance, permit
`ting a suf?ciently long optical path of from the concave,
`re?ective mirror to the image plane. Therefore, the cata
`dioptric projection optical system has a space permitting an
`aperture stop to be set therein, based on a siZe reduction of
`the beam splitting optical system such as a polariZing beam
`splitter. The catadioptric projection optical system can be
`applied to the projection exposure apparatus of the scanning
`exposure method, based on use of a compact beam splitting
`optical system. Besides the projection exposure apparatus of
`the one-shot exposure method, the catadioptric projection
`optical system can be also applier to recent apparatus
`employing a scanning exposure method such as the slit scan
`method or the step-and-scan method, etc. for effecting
`exposure While relatively scanning the reticle and the Wafer
`to the projection optical system.
`To achieve the above object, as shoWn in FIG. 1, an
`exposure apparatus of the present invention comprises at
`least a Wafer stage 3 alloWing a photosensitive substrate W
`to be held on a main surface thereof, an illumination optical
`system 1 for emitting exposure light of a predetermined
`Wavelength and transferring a predetermined pattern of a
`mask (reticle R) onto the substrate W, a catadioptric projec
`tion optical system 5 provided betWeen a ?rst surface P1 on
`Which the mask R is disposed and a second surface P2 to
`Which a surface of the substrate W is corresponded, for
`projecting an image of the pattern of the mask R onto the
`substrate W. The illumination optical system 1 includes an
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
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`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 15
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`

`

`3
`splitter 10PBS and a quarter Wave plate 9 be placed betWeen
`the polarizing beam splitter and the concave, re?ective
`mirror M2. Further, it is desired that the optical system be
`telecentric at least on the image plane P2 side.
`Next, the catadioptric projection optical system in FIG. 17
`is an optical system for projecting an image of a pattern P10
`on a ?rst surface P1 onto a second surface P2 Which has a
`?rst image-forming optical system (G1(f1), G2(f2)) for form
`ing an intermediate image 11 of the pattern P10 of the ?rst
`surface P1, and a second image-forming optical system
`(G3(f3)) for forming an image of the intermediate image 11
`on the second surface P2.
`The ?rst image-forming optical system comprises a ?rst
`group G1(f1) of a positive refractive poWer, comprising a
`refractive lens component, for converging a light beam from
`the pattern P10 of the ?rst surface P1, a partial mirror 12 for
`separating a part of the light beam from the ?rst group by a
`?rst re?ective surface 12a arranged obliquely to the optical
`aXis AX1 of the ?rst group, and a second group G2(f2) of a
`positive refractive poWer, comprising a concave, re?ective
`mirror M2 for re?ecting the light beam of Which the part is
`separated by the partial mirror 12, for forming the interme
`diate image 11 of the pattern P10 near the partial mirror 12,
`in Which a part of the light beam converged by the second
`group is guided to the second image-forming optical system
`G3(f3). The partial mirror 12 is positioned so as to avoid
`being disposed on the optical aXis AX1 of the ?rst group and
`provided betWeen the ?rst group and the second group. The
`partial mirror 12 further has a second re?ective surface for
`guiding the re?ected light beam from the concave, re?ective
`mirror M2 to the second image-forming optical system, the
`second re?ective surface 12b being opposite to the ?rst
`re?ective surface 12a.
`In this case, because the light beam re?ected by a second
`surface 12b of the partial mirror 12 is used, it is desired that
`an image-forming range be slit or arcuate. Namely, the
`catadioptric projection optical system in FIG. 17 is suitable
`for applications to the projection eXposure apparatus of the
`scanning eXposure method. In this case, because the use of
`the partial mirror 12 includes little in?uence of repetitive
`re?ections, the quarter Wave plate can be obviated.
`In these arrangements, the folloWing conditions should be
`preferably satis?ed When individual PetZval sums of the ?rst
`group G1(f1), the second group G2(f2), and the second
`image-forming optical system G3(f3) are p1, p2, p3, respec
`tively.
`
`10
`
`15
`
`45
`
`(1)
`
`(2)
`
`(3)
`Further, the folloWing conditions should be preferably
`satis?ed When a magni?cation of primary image formation
`of from the pattern on the ?rst surface P1 to the intermediate
`image is [312, a magni?cation of secondary image formation
`of from the intermediate image to the image on the second
`surface P2 is [33, and a magni?cation of from the ?rst surface
`to the second surface is [3.
`
`013514205
`
`(4)
`
`(5)
`
`(6)
`
`65
`
`The catadioptric projection optical system in FIG. 2 is
`suitably applicable to the projection eXposure apparatus of
`
`5,808,805
`
`4
`the one-shot eXposure method. In this case, because the
`prism type beam splitter 10PBS is used to separate the light
`beam coming from the concave, re?ective mirror M2 from
`the light beam going to the concave, re?ective mirror M2
`and because the beam splitter 10PBS is located near the
`portion Where the light beam from the concave, re?ective
`mirror M2 is once converged to be focused, the prism type
`beam splitter 10PBS can be constructed in a reduced scale.
`In other Words, in the catadioptric projection optical system,
`since an intermediate image 11 of the pattern of the ?rst
`surface P1 is formed betWeen the concave, re?ective mirror
`M2 and the second image-forming optical system, the diam
`eter of the light beam traveling from the concave, re?ective
`mirror M2 to the beam splitter 10PBS Will become small.
`Also, because the image is once formed betWeen the
`concave, re?ective mirror M2 and the image plane P2, an
`aperture stop 6 can be placed in the second image-forming
`optical system G3(f3). Accordingly, a coherence factor (0
`value) can be readily controlled. With regard to this, because
`after the primary image formation, the secondary image
`formation is made by the second image-forming optical
`system G3(f3), the Working distance betWeen a fore end lens
`in the second image-forming optical system G3(f3) and the
`image plane P2 can be secured suf?ciently long. In
`particular, because the projection eXposure apparatus of the
`one-shot eXposure method employs the beam splitter 10PBS
`located near the plane of primary image formation, the beam
`splitter 10PBS can be made as small as possible.
`Next, because the catadioptric projection optical system
`in FIG. 17 uses the partial mirror 12, a best image region on
`the image plane P2 is slit or arcuate, thus being suitable for
`applications to the projection eXposure apparatus of the
`scanning eXposure method. In this case, because the image
`is once formed near the partial mirror 12, the partial mirror
`12 may be small in siZe and characteristics of a re?ective
`?lm of the partial mirror 12 are stable.
`Also, the optical path can be separated simply by provid
`ing the partial mirror 12 With a small angle of vieW. Namely,
`because a large angle of vieW is unnecessary for separation
`of the optical path, a suf?cient margin is left in the image
`forming performance. With regard to this, ordinary cata
`dioptric projection optical systems need a maXimum angle
`of vieW of about 20° or more for separation of the optical
`path, While an angle of vieW of the light beam entering the
`partial mirror 12 is about 10°, Which is easy in aberration
`correction.
`A so-called ring ?eld optical system is knoWn as a
`projection optical system for the scanning eXposure method,
`and the ring ?eld optical system is constructed to illuminate
`only an off-axis annular portion. It is, hoWever, dif?cult for
`the ring ?eld optical system to have a large numerical
`aperture, because it uses an off-axis beam. Further, because
`optical members in that system are not symmetric With
`respect to the optical aXis, processing, inspection, and
`adjustment of the optical members are dif?cult, and accuracy
`control or accuracy maintenance is also dif?cult. In contrast
`With it, because the angle of vieW is not large in the present
`invention, the optical system is constructed in a structure
`With less eclipse of beam.
`Since the ?rst image-forming optical system (G1(f1),
`G2(f2)) and the second image-forming optical system G3(f3)
`are constructed independently of each other, the optical
`system is easy in processing, inspection, and adjustment of
`optical members, is easy in accuracy control and accuracy
`maintenance, and has eXcellent image-forming characteris
`tics to realiZe a large numerical aperture.
`NeXt, in the catadioptric projection optical system shoWn
`in FIG. 2 or 17, a PetZval sum of the entire optical system
`
`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 16
`
`

`

`5,808,805
`
`5
`?rst needs to be set as close to 0, in order to further improve
`the performance of optical system. Therefore, conditions of
`equations (1) to (3) should be preferably satis?ed.
`Satisfying the conditions of equations (1) to (3) prevents
`curvature of the image plane in the optical performance,
`Which thus makes ?atness of the image plane excellent.
`Above the upper limit of the condition of equation (3) (or if
`p1+p2+p3§0.1), the image plane is curved as concave to the
`object plane; beloW the loWer limit of the condition of
`equation (3) (or if p1+p2+p3§—0.1), the image plane is
`curved as convex to the object, thereby considerably degrad
`ing the image-forming performance.
`When the conditions of equations (4) to (6) are satis?ed
`as to the magni?cation [312 of primary image formation, the
`magni?cation [33 of secondary image formation, and the
`magni?cation [3 of overall image formation, the optical
`system can be constructed Without dif?culties. BeloW the
`loWer limit of each condition of equation (4) to (6), the
`demagnifying ratio becomes excessive, Which makes Wide
`range exposure difficult. Above the upper limit, the demag
`nifying ratio becomes closer to magnifying ratios, Which is
`against the original purpose of use for reduction projection
`in applications to the projection exposure apparatus.
`In this case, because the condition of equation (4) is
`satis?ed, the most part of the demagnifying ratio of the
`overall optical system relies on the ?rst image-forming
`optical system. Accordingly, the beam splitter 10PBS or the
`partial mirror 12 can be constructed in a small scale in
`particular. If the position of the beam splitter 10PBS in FIG.
`2 or the partial mirror 12 in FIG. 6 as beam splitting means
`is made nearly coincident With the entrance pupil and the
`exit pupil of optical system, a shield portion on the pupil
`does not change against a change of object height, and
`therefore, no change of image-forming performance appears
`across the entire image plane.
`Also, it is desired that such an optical system for exposure
`be telecentric at least on the image plane side in order to
`suppress a change of magni?cation against variations in the
`direction of the optical axis, of the image plane Where the
`Wafer or the like is located.
`The present invention Will become more fully understood
`from the detailed description given hereinbeloW and the
`accompanying draWings Which are given by Way of illus
`tration only, and thus are not to be considered as limiting the
`present invention.
`Further scope of applicability of the present invention Will
`become apparent from the detailed description given here
`inafter. HoWever, it should be understood that the detailed
`description and speci?c examples, While indicating pre
`ferred embodiments of the invention, are given by Way of
`illustration only, since various changes and modi?cations
`Within the spirit and scope of the invention Will become
`apparent to those skilled in the art form this detailed descrip
`tion.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a structural draWing to shoW the basic structure
`of the exposure apparatus according to the present invention.
`FIG. 2 is a structural draWing to shoW the basic structure
`of the catadioptric projection optical system 5 in FIG. 1.
`FIG. 3 is an illustration of optical paths of a light beam
`traveling in the catadioptric projection optical system in
`FIG. 2.
`FIG. 4 is an optical path development of a ?rst embodi
`ment of the catadioptric projection optical system in FIG. 2,
`the optical path comprising the optical paths OP1, OP2, OP3
`shoWn in FIG. 3.
`
`15
`
`25
`
`35
`
`45
`
`55
`
`65
`
`6
`FIGS. 5 to 9 are aberration diagrams of the ?rst embodi
`ment.
`FIG. 10 is an optical path development of the projection
`optical system in the second embodiment.
`FIGS. 11 to 16 are aberration diagrams of the second
`embodiment.
`FIG. 17 is a structural draWing to shoW the basic structure
`of the projection optical system in the third embodiment.
`FIG. 18 is an optical path development of the projection
`optical system in the third embodiment.
`FIGS. 19 to 24 are aberration diagrams of the third
`embodiment.
`FIG. 25 is an optical path development of the projection
`optical system in the fourth embodiment.
`FIGS. 26 to 30 are aberration diagrams of the fourth
`embodiment.
`FIG. 31 is a structural draWing to shoW a structure of the
`catadioptric projection optical system applied to a common
`exposure apparatus.
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`Various embodiments of the catadioptric projection opti
`cal system according to the present invention Will be
`described With reference to the draWings. In the examples,
`the present invention is applied to the projection optical
`system in the projection exposure apparatus for projecting
`an image of patterns of reticle onto a Wafer coated With a
`photoresist. FIG. 1 shoWs a basic structure of the exposure
`apparatus according to the present invention. As shoWn in
`FIG. 1, an exposure apparatus of the present invention
`comprises at least a Wafer stage 3 alloWing a photosensitive
`substrate W to be held on a main surface 3a thereof, an
`illumination optical system 1 for emitting exposure light of
`a predetermined Wavelength and transferring a predeter
`mined pattern of a mask (reticle R) onto the substrate W, a
`light source 100 for supplying an exposure light to the
`illumination optical system 1, a catadioptric projection opti
`cal system 5 provided betWeen a ?rst surface P1 (object
`plane) on Which the mask R is disposed and a second surface
`P2 (image plane) to Which a surface of the substrate W is
`corresponded, for projecting an image of the pattern of the
`mask R onto the substrate W. The illumination optical
`system 1 includes an alignment optical system 110 for
`adjusting a relative positions betWeen the mask R and the
`Wafer W, and the mask R is disposed on a reticle stage 2
`Which is movable in parallel With respect to the main surface
`of the Wafer stage 3. A reticle exchange system 200 conveys
`and changes a reticle (mask R) to be set on the reticle stage
`2. The reticle exchange system 200 includes a stage driver
`for moving the reticle stage 2 in parallel With respect to the
`main surface 3a of the Wafer stage 3. The catadioptric
`projection optical system 5 has a space permitting an aper
`ture stop 6 to be set therein. The sensitive substrate W
`comprises a Wafer 8 such as a silicon Wafer or a glass plate,
`etc., and a photosensitive material 7 such as a photoresist or
`the like coating a surface of the Wafer 8. The Wafer stage 3
`is moved in parallel With respect to a object plane P1 by a
`stage control system 300. Further, since a main control
`section 400 such as a computer system controls the light
`source 100, the reticle exchange system 200, the stage
`control system 300 or the like, the exposure apparatus can
`perform a harmonious action as a Whole.
`The techniques relating to an exposure apparatus of the
`present invention are described, for example, in US. patent
`
`CARL ZEISS V. NIKON
`IPR2013-00362
`Ex. 2010, p. 17
`
`

`

`5,808,805
`
`7
`applications Ser. No. 255,927, No. 260,398, No. 299,305,
`US. Pat. No. 4,497,015, No. 4,666,273, No. 5,194,893, No.
`5,253,110, No. 5,333,035, No. 5,365,051, No. 5,379,091, or
`the like. The reference of Us. patent application Ser. No.
`255,927 teaches an illumination optical system (using a laser
`source) applied to a scan type exposure apparatus. The
`reference of US. patent application Ser. No. 260,398
`teaches an illumination optical system (using a lamp source)
`applied to a scan type exposure apparatus. The reference of
`US. patent application Ser. No. 299,305 teaches an align
`ment optical system applied to a scan type exposure appa
`ratus. The reference of US. Pat. No. 4,497,015 teaches an
`illumination optical system (using a lamp source) applied to
`a scan type exposure apparatus. The reference of Us. Pat.
`No. 4,666,273 teaches a step-and repeat type exposure
`apparatus capable of using the catadioptric projection optical
`system of the present invention. The reference of US. Pat.
`No. 5,194,893 teaches an illumination optical system, an
`illumination region, mask-side and reticle-side
`interferometers, a focusing optical system, alignment optical
`system, or the like. The reference of US. Pat. No. 5,253,110
`teaches an illumination optical system (using a laser source)
`applied to a step-and-repeat type exposure apparatus. The
`’110 reference can be applied to a scan type exposure
`apparatus. The reference of Us. Pat. No. 5,333,035 teaches
`an application of an illumination optical system applied to
`an exposure apparatus. The reference of Us. Pat. No.
`5,365,051 teaches a auto-focusing system applied to an
`exposure apparatus. The reference of US. Pat. No. 5,379,
`091 teaches an illumination optical system (using a laser
`source) applied to a scan type exposure apparatus.
`In each embodiment as described beloW, a lens arrange
`ment is illustrated as an optical path development, for
`example as shoWn in FIG. 4. In each optical path
`development, a re?ective surface is shoWn as a transmissive
`surface, and optical elements are arranged in the order in
`Which light from a reticle R passes. Also, a virtual plane of
`?at surface (for example r15) is used at a re?ective surface
`of a concave, re?ective mirror (for example r14). In order to
`indicate a shape and separation of lens, for example as
`shoWn in FIG. 4, the pattern surface of reticle R is de?ned
`as the Zeroth surface, surfaces that the light emergent from
`the reticle R passes in order before reaching the Wafer W are
`de?ned as i-th surfaces (i=1, 2, .
`.
`. ), and the sign for radii
`ri of curvature of the i-th surfaces is determined as positive
`if a surface is convex to the reticle 10 in the optical path
`development. A surface separation betWeen the i-th surface
`and the (i+1)-th surface is de?ned as di. SiO2 as a glass
`material means silica glass. Arefractive index of silica glass
`for reference Wavelength (193 nm) used is as folloWs.
`silica glass: 1.56100
`First Embodiment
`The ?rst embodiment is a projection optical system With
`a magni?cation of 1Ax, suitably applicable to the projection
`exposure apparatus of the one-shot exposure method
`(steppers etc.). This ?rst embodiment is an embodiment
`corresponding to the optical system of FIG. 2 as Well. FIG.
`4 is an optical path development of the projection optical
`system of the ?rst embodiment. As shoWn in FIG. 4, light
`from the patterns on the reticle R travels through a ?rst
`converging group G1 consisting of four refractive lenses and
`then is re?ected by a beam splitter surface (r10) in a cubic
`polariZing beam splitter 10A. An optical path of the light is
`corresponded to the optical path OPl in FIG.3. The re?ected
`light passes through a quarter Wave plate 9 (not shoWn in
`FIG. 4) to reach a second converging group G2 consisting of
`
`10
`
`15
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`8
`a negative meniscus lens L2O and a co