The undersigned, of
`
`x
`
`VERIFICATION
`
`the below address, hereby certifies
`
`that he/she well knows both the English and Japanese languages,
`
`and that the attached is an accurate English translation of the
`
`Japanese Patent application filed on October 9, 2003 under No.
`
`P2003-350647.
`
`The undersigned declares further that all statements made
`
`herein »of his/her
`
`own
`
`.knowledge
`
`are
`
`true
`
`and
`
`that all
`
`statements made on information and belief are believed to be
`
`true;
`
`and further
`
`that
`
`these statements were made with the
`
`knowledge that willful
`
`false statements and the like so made
`
`are punishable by fine or imprisonment, or both, under Section
`
`1001 of Title 18 of
`
`the United States Code
`
`and that
`
`such
`
`willful
`
`false statements may jeopardize the validity of
`
`the
`
`application or any patent issuing thereon.
`
`Signed this
`
`20th
`
`day of
`
`February
`
`, 2008.
`
`Signature:
`
`Address:
`
`c/o Soei Patent
`
`& Law Firm Ginza First Bldg.,
`
`10-6, Ginza
`
`l—chome, Chuo—ku, Tokyo
`
`104-0061
`
`Japan
`
`
`
`
`
`Zfi SS 1108
`
`1
`
`
`
`x
`
`VERIFICATION
`
`the below address, hereby certifies
`
`that he/she well knows both the English and Japanese languages,
`
`and that the attached is an accurate English translation of the
`
`Japanese Patent application filed on October 9, 2003 under No.
`
`P2003-350647.
`
`The undersigned declares further that all statements made
`
`herein »of his/her
`
`own
`
`.knowledge
`
`are
`
`true
`
`and
`
`that all
`
`statements made on information and belief are believed to be
`
`true;
`
`and further
`
`that
`
`these statements were made with the
`
`knowledge that willful
`
`false statements and the like so made
`
`are punishable by fine or imprisonment, or both, under Section
`
`1001 of Title 18 of
`
`the United States Code
`
`and that
`
`such
`
`willful
`
`false statements may jeopardize the validity of
`
`the
`
`application or any patent issuing thereon.
`
`Signed this
`
`20th
`
`day of
`
`February
`
`, 2008.
`
`Signature:
`
`Address:
`
`c/o Soei Patent
`
`& Law Firm Ginza First Bldg.,
`
`10-6, Ginza
`
`l—chome, Chuo—ku, Tokyo
`
`104-0061
`
`Japan
`
`
`
`
`
`Zfi SS 1108
`
`1
`
`
`
`PATENT OFFICE
`
`JAPANESE GOVERNNIENT
`
`This is to certify that the annexed is a true copy of the following
`
`application as filed with this Ofiice.
`
`Date of Application:
`
`October 9, 2003
`
`Application Number:
`
`Japanese Patent Application
`
`N02003-350647
`
`Applicant(s): NIKON CORPORATION
`
`Commissioner,
`
`Patent Office
`
`(Seal)
`
`2
`
`
`
`JP2003—350647
`
`. (Document Name)
`
`Patent Application
`
`(Reference Number)
`
`03-067 INK
`
`(Presentation Date)
`
`October 9, 2003
`
`(Directly)
`
`(IPC)
`
`(Inventor)
`
`Commissioner of the Patent Office
`
`HOIL 21/027
`
`(Residence or Address)
`
`c/o NIKON CORPORATION,
`
`2-3, Marunouchi 3-chorne, Chiyoda-ku, Tokyo
`
`(Name)Yasuhiro OMURA
`
`(Applicant)
`
`(Identification Number)
`
`000004112
`
`(Name)NIKON CORPORATION
`
`(Attorney)
`
`(Identification Number)
`
`1 00 1 12427
`
`(Patent Attorney)
`
`(Name)Yo shihiro FUJIIVIOTO
`
`(Official Fee)
`
`(Pre—Paid Master Note Number)
`
`168687
`
`(Amount to be paid)
`
`21,000 yen
`
`(Lists of the Article to be presented)
`
`(Name of Article)
`
`Claims
`
`1
`
`(Name of Article)
`
`Specification
`
`1
`
`(Name of Article)
`
`Drawing
`
`1
`
`(Name ofArticle)
`
`Abstract
`
`1
`
`(General Power ofAttorney Number)
`
`0016868
`
`ii
`
`3
`
`
`
`JP2003-350647
`
`[Claims]
`
`[Claim 1]
`
`A catadioptric projection optical system for forming an image of a first
`
`plane on a second plane, comprising:
`
`a first
`
`imaging optical system comprising two mirrors,
`
`for
`
`forming an intermediate image of the first surface; and
`
`a second imaging optical system for forming the intermediate
`
`image on the second surface,
`
`wherein the second imaging optical system comprises the
`
`10
`
`following components in order of passage of a ray from the intermediate
`
`image side:
`
`a first field mirror of a concave shape;
`
`a second field mirror;
`
`I a first lens unit comprising at least two negative lenses, and
`
`15
`
`having a negative refracting power;
`
`a second lens unit having a positive refracting power;
`
`an aperture stop; and
`
`a third lens unit having a positive refracting power.
`
`[Claim 2]
`
`20
`
`The catadioptric projection optical system according to Claim 1,
`
`wherein the first imaging optical system comprises a fourth lens
`
`unit having a positive refracting power, a negative lens, a concave
`
`mirror, and an optical path separating mirror, and
`
`wherein the first imaging optical system is arranged as follows:
`
`25
`
`light traveling in the first imaging optical system passes through the
`
`fourth lens unit and the negative lens, is then reflected by the concave
`
`4
`
`
`
`JP2003-350647
`
`mirror, and passes again through the negative lens to be guided to the
`
`optical path separating mirror; the light reflected by the optical path
`
`separating mirror is reflected by the first field mirror and the second
`
`field mirror and thereafier directly enters the first lens unit in the second
`
`imaging optical system.
`
`[Claim 3]
`
`The catadioptric projection optical system according to Claim 1 or 2,
`
`wherein the first field mirror outputs light entering the first field
`
`mirror, so as to bend the light into a direction toward the optical axis of
`
`10
`
`the catadioptric projection optical system.
`
`[Claim 4]
`
`The catadioptric projection optical system according to any one of
`
`Claims 1 to 3,
`
`wherein the second field mirror has a convex shape.
`
`15‘
`
`[Claim 5]
`The catadioptric projection optical system according to any one of
`
`Claims 1 to 4,
`
`wherein said two mirrors in the first imaging optical system are
`
`a mirror of a concave shape and a mirror of a convex shape which are
`
`20
`
`arranged in order of incidence of light from the first surface, and
`
`wherein the second field mirror in the second imaging optical system is
`
`a mirror of a convex shape.
`
`[Claim 6]
`
`The catadioptric projection optical system according to any one of
`
`25
`
`Claims 1 to 5,
`
`wherein the aperture stop is disposed between the first field
`
`5
`
`
`
`JP2003—3 50647
`
`mirror and the second surface,
`
`the projection optical system satisfying the following condition:
`
`0.17 < M/L < 0.6,
`
`where M is a distance on an optical axis between the first field
`
`mirror and the second surface, and L a distance between the first surface
`
`and the second surface.
`
`[Claim 7]
`
`10
`
`15
`
`The catadioptric projection optical system according to any one of
`
`Claims 1 to 6,
`
`wherein the first lens unit in the second imaging optical system
`
`has at least one aspherical lens.
`
`[Claim 8]
`
`A catadioptric projection optical system for forming an image of a first
`
`surface on a second surface, the projection optical system comprising:
`
`a first unit disposed in an optical path between the first surface
`
`and the second surface and having a positive refiacting power;
`
`a second unit disposed in an optical path between the first unit
`
`and the second surface and comprising at least four mirrors;
`
`a third unit disposed in an optical path between the second unit
`
`20
`
`and the second surface, comprising at least two negative lenses, and
`
`having a negative refracting power; and
`
`a fourth unit disposed in an optical path between the third unit
`
`and the second surface, comprising at least three positive lenses, and
`
`having a positive refracting power,
`
`25
`
`wherein an intermediate image is formed in the second unit and
`
`wherein an aperture stop is provided in the fourth unit.
`
`6
`
`
`
`JP2003-350647
`
`[Claim 9] The catadioptric projection optical system according to Claim V_
`
`8,
`
`wherein the second unit comprises the following components in
`
`order of incidence of light from the first surface: a first reflecting mirror
`
`of a concave shape; a second reflecting mirror of a convex shape; a third
`
`reflecting mirror of a concave shape; and a fourth reflecting mirror of a
`
`convex shape.
`
`[Claim 10]
`
`The catadioptric projection optical system according to any one of
`
`10
`
`Claims 8 and 9,
`
`wherein the second unit comprises at least one negative lens,
`
`and wherein an optical element located nearest to the third unit in an
`
`optical path of the second unit is the fourth reflecting mirror or a double
`
`pass lens through which light passes twice.
`
`15
`
`[Claim 11]
`
`The catadioptric projection optical system according to any one of
`
`Claims 8 to 10,
`
`wherein the third reflecting mirror outputs light entering the
`
`third reflecting mirror, so as to bend the light into a direction toward the
`
`20
`
`optical axis of the catadioptric projection optical system.
`
`[Claim 12]
`
`The catadioptric projection optical system according to any one of
`
`Claims 8 to 11,
`
`wherein the aperture stop is disposed between the third
`
`25
`
`reflecting mirror and the second surface,
`
`the projection optical system satisfying the following condition:
`
`7
`
`
`
`JP2003—350647
`
`0.17 < Ma/L < 0.6,
`
`where Ma is a distance on an optical axis between the third
`
`reflecting mirror and the second surface, and L a distance between the
`
`first surface and the second surface.
`
`[Claim 13]
`
`The catadioptric projection optical system according to any one of
`
`Claims 8 to 12,
`
`wherein the third unit comprises at least one aspherical lens.
`
`[Claim 14]
`
`10
`
`The catadioptric projection optical system according to any one of
`
`Claims 1 to 13,
`
`wherein a lens surface on the first surface side of a lens located
`
`nearest to the second surface out of lenses in the catadioptric projection
`
`optical system has a positive refracting power, and
`
`15
`
`wherein, where a refractive index of an atmosphere in the
`
`catadioptric projection optical system is 1, a medium having a refractive
`
`index larger than 1.1 is interposed in an optical path between the lens
`
`nearest to the second surface, and the second surface.
`
`[Claim 15]
`
`20
`
`The catadioptric projection optical system according to any one of
`
`Claims 1
`
`to 14, which is the catadioptric projection optical system
`
`according to any one of Claims 1 to 14,
`
`wherein an optical axis of every optical element with a
`
`predetermined refi'acting power in the catadioptric projection optical
`
`25
`
`system is arranged substantially on a single straight line, and
`
`wherein a region of an image formed on the second surface by
`
`8
`
`
`
`JP2003-350647
`
`the catadioptric projection optical system is an off-axis region not
`
`including the optical axis.
`
`[Claim 16]
`
`An exposure apparatus for effecting an exposure of a pattern formed on
`
`a mask, onto a photosensitive substrate,
`
`the exposure apparatus
`
`comprising:
`
`an illumination system for illuminating the mask set on the first
`
`surface; and
`
`the catadioptric projection optical system as set forth in any one
`
`10
`
`of Claims 1 to 15, for forming an image of the pattern formed on the
`
`mask, on the photosensitive substrate set on the second surface.
`
`[Claim 17]
`
`a
`
`An exposure method of effecting an exposure of a pattern formed on a
`
`mask, onto a photosensitive substrate, the exposure method comprising:
`
`15
`
`an illumination step of illuminating the mask on which the
`
`predetermined pattern is formed; and '
`
`an exposure step of performing an exposure of the pattern of the
`
`mask set on the first surface, onto the photosensitive substrate set on the
`
`second surface, using the catadioptric projection optical system as set
`
`20
`
`forth in any one of Claims 1 to 15.
`
`[Document Name] Specification
`
`[Title of the Invention]
`
`Catadioptric projection optical system, exposure apparatus and exposure
`
`method
`
`25
`
`[Detailed Description of the Invention]
`
`[0001]
`
`9
`
`
`
`JP2003—350647
`
`[Technical Field to which the Invention Pertains]
`
`[0001]
`
`The present invention relates to a catadioptric projection optical system
`
`using immersion method used for transferring a mask pattern onto a
`
`photosensitive substrate in a photolithography step of manufacturing
`
`semiconductor elements or the like, and to an exposure apparatus and an
`
`exposure method using the catadioptric projection optical system.
`
`[Prior Art]
`
`[0002]
`
`10
`
`In manufacturing semiconductor elements or the like, such an exposure
`
`apparatus that an image of a pattern of a reticle as a mask is projected
`
`and exposed, via a projection optical system, onto a wafer (or glass plate
`
`or the like), on which a resist as a photosensitive substrate is coated, is
`
`adopted.
`
`15
`
`[0003]
`
`In recent years, miniaturization has been increasingly accelerated in the
`
`manufacturing of semiconductor elements or of semiconductor chip
`
`mounted substrates, and there has been an increasing demand for a
`
`projection optical system with higher resolving power to be used in the
`
`20
`
`exposure apparatus for baking of patterns.
`
`In order to meet
`
`the
`
`demand for high-resolution, wavelength of an exposure light should be
`
`made shorter and numerical aperture of the projection optical system
`
`should be increased. However, if wavelength of the exposure light is
`
`made shorter, types of optical glasses capable of withstanding practical
`
`25
`
`applications are limited due to absorption of a light. For example, with
`
`wavelength less than 180 nm, glass material practically applicable is
`
`10
`
`10
`
`
`
`JP2003-350647
`
`fluorite alone.
`
`[0004]
`
`In the case where one attempts to constitute a projection optical system
`
`having a large numerical aperture using refracting optical members (lens,
`
`parallel flat plate or the like) only, and Petzval's conditions should be
`
`met, there is no way but to upsize the refracting optical members
`
`constituting the projection optical system,
`
`i.e., the projection optical
`
`system should inevitably be made large. Then, a projection optical
`
`system composed of reflecting optical members only or a combination
`
`10
`
`of refracting optical members and reflecting optical members has been
`
`proposed (for example, see patent document 1).
`
`[0005]
`
`Further, with shortening of wavelength of an exposure light, glass
`
`materials having transmittance capable of securing light volume
`
`15
`
`sufficient
`
`for
`
`the
`
`expoSure while maintaining desired imaging
`
`performance are limited. Therefore, a liquid immersion type exposure
`
`apparatus with improved resolution realized by making use of a fact that
`
`wavelength of an exposure light in the liquid is l/n times (n denotes
`
`refractive index of the liquid and is normally in the range of
`
`20
`
`approximately 1.2 to 1.6) that in the air has been propOsed in which
`
`water or a liquid such as organic solvent is filled between the lower
`
`surface of the projection optical system and wafer surface (for example,
`
`see patent document 2).
`
`[Patent document 1] Japanese Patent Laid-Open No. 2002-277742
`
`25
`
`[Patent document 2] Japanese Patent Laid-Open No. Hei 10—303 114
`
`[Disclosure of the Invention]
`
`11
`
`11
`
`
`
`JP2003-350647
`
`[Problems to be Solved by the Invention]
`
`[0006]
`
`However,
`
`in the projection optical system composed of only
`
`reflecting optical members and the projection optical system composed
`of a combination of refracting optical members and reflecting optical
`
`members, with increase in the numerical aperture,
`
`it becomes more
`
`difficult
`
`to separate optical path between a light flux entering a
`
`reflecting optical member and a light flux reflected by the reflecting
`
`optical member and it is infeasible to avoid upsizing of the reflecting
`
`10
`
`optical member, i.e., upsizing of the projection optical system.
`
`[0007]
`
`In order
`
`to achieve simplification of manufacturing and
`
`simplification of mutual adjustments of optical members, it is desirable
`
`to construct a catadioptric projection optical system of a single optical
`
`15
`
`axis;
`
`in this case, with increase in the numerical aperture,
`
`it also
`
`becomes difficult to separate the optical path between the light entering
`
`the reflecting optical member and the light reflected by the reflecting
`
`optical member, and accordingly the projection optical system is
`
`upsized.
`
`20
`
`[0008]
`
`An object of the present invention is to provide a catadioptric
`
`projection optical system with large numerical aperture using liquid
`
`immersion method without upsizing optical members constituting the
`
`catadioptric projection optical system, and to provide an exposure
`
`25
`
`apparatus using the catadioptric projection optical system and an
`
`exposure method.
`
`12
`
`12
`
`
`
`JP2003-350647
`
`[Means for Solving the Problem]
`
`[0009]
`
`A catadioptric projection optical system according to Claim 1
`
`comprises two mirrors in the catadioptric projection optical system
`
`which forms an image of a first surface on a second surface, comprises a
`
`first imaging optical system which forms an intermediate image of the
`
`first surface and a second imaging optical system which forms the
`
`intermediate image on the second surface, wherein the second imaging
`
`optical system includes,
`
`in the order of passage of a ray fi'om the
`
`10
`
`intermediate image side, a first field mirror of a concave shape, a second
`
`field mirror, and at least two negative lenses, and comprises a first lens:
`
`unit having a negative refracting power, a second lens unit having a
`
`positive refracting power, an aperture stop, and a third lens unit having a
`
`positive refi‘acting power.
`
`15
`
`[0010]
`
`'
`
`Since the catadioptric projection optical system according to
`
`Claim 1 forms an intermediate image of a first surface in a first imaging
`
`optical system, even in the case where numerical aperture of a
`
`catadioptric projection optical system is increased, it becomes possible
`
`20
`
`to separate easily and surely optical path between a light flux toward a
`
`first surface side and a light flux toward a second surface. Further,
`
`since a first lens unit having a negative refracting power is provided in a
`
`second imaging optical
`
`system, entire length of the catadioptric
`
`projection optical system can be made short, and adjustments to satisfy
`
`25
`
`Petzval's conditions can be made with ease. Furthermore, the first lens
`
`unit relieves scatterings due to difference of field angles of the light flux
`
`10
`
`13
`
`13
`
`
`
`JP2003-350647
`
`widened by the first field mirror and suppresses an occurrence of
`
`aberration. Therefore, even in the case Where numerical aperture at
`
`object side and at
`
`image side in the catadioptric projection optical
`
`system is increased for the sake of improvement of a resolution, good
`
`imaging performance can be obtained over entire exposure region.
`
`[0011]
`
`Further, a catadioptn'c projection optical system according to
`
`Claim 2, wherein the first imaging optical system comprises a fourth
`
`lens unit having a positive refi‘acting power, a negative lens, a concave
`
`10
`
`mirror, and an optical path separating mirror, and wherein the first
`
`imaging optical system is arranged as follows: light traveling in the first
`
`imaging optical system passes through the fourth lens unit and the
`
`negative lens, is then reflected by the concave mirror, and passes again
`
`through the negative lens to be guided to the optical path separating ‘
`
`15
`
`‘ mirror;
`
`the light reflected by the optical path separating mirror is
`
`Oreflected by the first field mirror and the second field mirror and
`
`thereafier directly enters the first lens unit in the second imaging optical
`
`system.
`
`[0012]
`
`20
`
`According to the catadioptric projection optical system as set
`
`forth in Claim 2, since the first imaging optical system comprises a
`
`fourth lens unit having a positive refracting power, it is possible to make
`
`the first surface side telecentric. Additionally, since the first imaging
`
`optical system has a negative lens and a concave mirror, adjustments to
`
`25.
`
`satisfy Petzval's conditions can be made with ease by regulating this
`
`negative lens and the concave mirror.
`
`11
`
`14
`
`14
`
`
`
`JP2003—350647
`
`[0013]
`
`Further, according to the catadioptric projection optical system
`
`as set forth in Claim 3, the first field mirror outputs light entering the
`first field mirror, so as to bend the light into a direction toward an
`
`optical axis of the catadioptric projection optical system.
`
`[0014]
`
`Further, according to the catadioptric projection optical system
`
`as set forth in Claim 4, the second field mirror has a convex shape.
`
`[0015]
`
`10
`
`According to the catadioptric projection optical system as set
`
`forth in Claims'3 and 4, since a ray entering the first field mirror is bent
`
`in the direction toward an optical axis of the catadioptric projection
`
`optical system and is output, even in the case where numerical aperture
`
`of [the catadioptric projection optical system is increased, the second
`
`15
`
`field mirror can be made smaller.
`
`Therefore,
`
`in the case where
`
`numerical aperture at object side and at image side is increased, optical
`
`path separation between a light flux towards the first surface side and a
`
`light flux towards the second surface side can be made with ease.
`
`[0016]
`
`20
`
`Further, according to the catadioptric projection optical system
`
`as set forth in Claim 5, wherein the two mirrors in the first imaging
`
`optical system are a mirror of a concave shape and amirror of a convex
`
`shape which are arranged in the order of incidence of light fiom the first
`
`surface, and wherein the second field mirror in the second imaging
`
`25
`
`optical system is a mirror of a convex shape.
`
`[0017]
`
`12
`
`15
`
`15
`
`
`
`J P2003-350647
`
`According to the catadioptric projection optical system as set
`
`forth in Claim 5, since two mirrors included in the first imaging optical
`
`system are of concave shape and convex shape, and the second field
`
`mirror has a convex shape, a light flux output from the first imaging
`
`optical system can be guided to the second imaging optical system
`
`easily and surely.
`
`[0018]
`
`According to the catadioptric projection optical system as set
`
`forth in Claim 6, wherein the aperture stop is disposed between the first
`
`10
`
`filed mirror and the second surface, the catadioptric projection optical
`
`system satisfying the condition of 0.17 <M/L< 0.6, where M is a
`
`distance on the optical axis between the first field mirror and the second
`
`surface, and L a distance between the first surface and the second
`
`surface.
`
`15
`
`[0019]
`
`According to the catadioptric projection optical system as set
`
`forth in Claim 6, since M/L is larger than 0.17, it is possible to avoid
`
`mechanical interferences between a first field mirror, and a first lens
`
`unit and a second lens unit.
`
`In addition, since M/L is smaller than 0.6,
`
`20
`
`elongation and upsizing of entire length of the catadioptric projection
`
`optical system can be avoided.
`
`[0020]
`
`Further, according to the catadioptric projection optical system
`
`as set forth in Claim 7, the first lens unit included in the second imaging
`
`25
`
`optical system has at least one aspherical lens.
`
`[0021]
`
`13
`
`16
`
`16
`
`
`
`JP2003 -3 50647
`
`According to the catadioptric projection optical system, as set
`
`forth in Claim 7, since at least one optical element constituting a first
`
`lens unit has a lens of aspherical shape, even in the case where
`
`numerical aperture at object side and at image side is increased, it is
`
`possible to obtain good imaging performances over entire exposure
`
`region.
`
`[0022]
`
`In the catadioptric projection optical system for forming an
`
`image of a first surface on a second surface, the catadioptric projection
`
`10
`
`optical system according to Claim 8 comprising: a first unit disposed in
`
`an optical path between the first surface and the second surface and.
`
`having a positive refracting power; a second unit disposed in an optical
`
`path between the first surface and the second surface and comprising at
`
`least-four mirrors; a third unit disposed in an optical path between the
`
`15
`
`second unit and the second surface, comprising at least two negative
`
`lenses, and having a negative refi‘acting power; a fourth unit disposed in
`
`an optical path between the third unit and the second surface,
`
`comprising at
`
`least
`
`three positive lenses, and having a positive
`
`refracting power; and wherein an intermediate image is formed in the
`
`20
`
`second unit and wherein an aperture stop is provided in the fourth unit.
`
`[0023]
`
`Further, according to the catadioptric projection optical system
`
`as set forth in Claim 8, even in the case where numerical aperture of the
`
`catadioptric projection optical system is increased for the sake of
`
`25
`
`formation of an intermediate image of a first surface in a second unit,
`
`optical path separation between a light flux toward the first surface side
`
`14
`
`17
`
`17
`
`
`
`JP2003-350647
`
`and a light flux toward the second surface side can be made easily and
`
`surely. Moreover, since a third unit having a negative refi'acting power
`
`is provided, entire length of the catadioptric projection optical system
`can be made short, and adjustments to satisfy Petzval's conditions can
`
`be made with ease. Therefore, even in the case where numerical
`
`aperture at object side and at image side in the catadioptric projection
`
`optical system is increased for the sake of improvement of a resolution,
`
`it is possible to obtain good imaging performance over entire exposure
`
`region.
`
`[0024]
`
`10
`
`According to the catadioptric projection optical system as set
`
`forth in Claim 9, wherein the second unit comprises, in the order of
`
`incidence of light from the first surface: a first reflecting mirror of a
`
`concave shape; a second reflecting mirror of a convex shape; a third
`
`15
`
`reflecting mirror of a concave shape; and a fourth reflecting mirror of a
`
`convex shape.
`
`[0025]
`
`According to the catadioptric projection optical system as set
`
`20
`
`forth in Claim 9, since the catadioptric projection optical system
`comprises, in the order of incidence of light from the first surface, a I
`
`concave mirror, a convex mirror, a concave mirror, a convex mirror, it is
`
`possible to guide a light flux output fiom the first imaging optical
`
`system to the second imaging optical system easily and surely.
`
`[0026]
`
`25
`
`Further, according to the catadioptric projection optical system
`
`as set forth in Claim 10, wherein the second unit comprises at least one
`
`15
`
`18
`
`18
`
`
`
`JP2003 -350647
`
`negative lens, and wherein an optical element located nearest to the
`
`third unit in an optical path of the second unit is the fourth reflecting
`
`mirror or a double pass lens through which light passes twice.
`
`[0027]
`
`According to the catadioptric projection optical system as set
`
`forth in Claim 10, since the optical element located nearest to the third
`
`unit side in the optical path of the second unit is the fourth reflecting
`
`mirror or the double pass lens through which light passes twice,
`
`adjustments to satisfy Petzval's conditions can be made with ease by
`
`10
`
`regulating lenses included in the third unit having a negative refracting
`
`power, and the fourth reflecting mirror or the double pass lens.
`
`[0028]
`
`Further, according to the catadioptric projection optical system
`
`as set forth in Claim 11, wherein the third reflecting mirror outputs light
`
`15
`
`entering the third reflecting mirror, so as to bend the light into a
`
`direction toward an optical axis of the catadioptric projection optical
`
`system.
`
`[0029]
`
`According to the catadioptric projection optical system as set
`
`20
`
`forth in Claim 11, since light entering the third reflecting mirror is bent
`
`and output in the direction toward an optical axis of the catadioptric
`
`projection optical system,
`
`it
`
`is possible to make a fourth reflecting
`
`mirror small in size. Therefore, even in the case where the numerical
`
`aperture at object side and at image side is increased for the sake of
`
`25
`
`improvement of a resolution,
`
`it is possible to separate optical path
`
`between a light flux toward the first surface side and a light flux toward
`
`16
`
`19
`
`19
`
`
`
`JP2003—350647
`
`the second surface side easily and surely.
`
`[0030]
`
`Further, according to the catadioptric projection optical system
`
`as set forth in Claim 12, wherein the aperture stop is disposed between
`
`the third reflecting mirror and the second surface,
`
`the catadioptric
`
`projection optical system satisfying the condition of 0.17 <1\/I/L< 0.6,
`
`where M is a distance on the optical axis between the third reflecting
`
`mirror and the second surface, and L a distance between the first surface
`
`and the second surface.
`
`10
`
`[003 1]
`
`According to the catadioptric projection optical system as set:
`
`forth in Claim 12, since M/L is larger than 0.17, it is possible to avoid
`
`mechanical interferences among a third reflecting mirror, and a second
`
`unit and a third unit. Moreover, since 1VI/L is smaller than 0.6,
`
`15
`
`elongation and upsizing of entire length of the catadioptric projection
`
`optical system can be avoided.
`
`[0032]
`
`Further, according to the catadioptric projection optical system
`
`as set forth in Claim 13, the third unit comprises at least one aspherical
`
`20
`
`lens.
`
`[0033]
`
`According to the catadioptric projection optical system as set
`
`forthin Claim 13, since at least one optical element constituting the
`
`third unit has an aspherical lens, even in the case where numerical
`
`25
`
`aperture at object side and at image side is increased, it is possible to
`
`obtain good imaging performance over entire exposure region.
`
`17
`
`20
`
`20
`
`
`
`JP2003-350647
`
`[0034]
`
`According to the catadioptric projection optical system as set
`
`forth in Claim 14, wherein a lens surface on the first surface side of a
`
`lens located nearest
`
`to the second surface out of lenses in the
`
`catadioptric projection optical system has a positive refracting power,
`
`and wherein, where a refractive index of an atmosphere in the
`
`catadioptric projection optical system is considered is 1, a medium
`
`having a refractive index larger than 1.1 is interposed in an optical path
`
`between the lens nearest to the second surface, and the second surface.
`
`10
`
`[0035]
`
`According to the catadioptric projection optical system as set
`
`forth in Claim 14, since a medium having refractive index larger than
`
`1.1 is interposed in an optical path between a lens located nearest to the
`
`second surfaceside of the catadioptric projection optical system and the
`
`15
`
`second surface, it is possible to improve the resolution due to that a
`
`wavelength of an exposure light in the medium becomes 1/n (where n
`
`denotes refiactive index of the medium) that of in the air.
`
`\ A
`
`[003 6]
`
`ccording to the catadioptric projection optical system as set
`
`2O
`
`forth in Claim 15, wherein an optical axis of every optical element with
`
`a predetermined refracting power in the catadioptric projection optical
`system is arranged substantially on a single straight line, and wherein a
`
`region of an image formed on the second surface by the catadioptric
`
`projection optical system is an off-axis region not including the optical
`
`'25
`
`ax15.
`
`[003 7]
`
`18
`
`21
`
`21
`
`
`
`JP2003—350647
`
`According to the catadioptric projection optical system as set
`
`forth in Claim 15, since an optical axis of every optical element
`
`included in the catadioptric projection optical system is arranged
`
`substantially on a single straight line, it is possible to reduce the degree
`
`of difficulty of manufacturing the catadioptric projection optical system,
`
`thereby facilitate relative adjustments of each optical member.
`
`[0038]
`
`Further, according to the exposure apparatus as set forth in
`
`Claim 16, the exposure apparatus comprises a catadioptric prOjection
`
`10
`
`optical system according to any one of Claims
`
`1
`
`to 15 and an
`
`illumination optical system for illuminating a mask disposed on the first.
`
`surface, and effects exposures of a pattern formed on the mask via the
`
`catadioptric projection optical system onto a photosensitive substrate
`
`disposed on the second surface.
`
`15
`
`[0039]
`
`According to the exposure apparatus as set forth in Claim 16,
`
`since the exposure apparatus comprises a catadioptric projection optical
`
`system which is compact in size and has a large numerical aperture, it is
`
`possible to expose a fine pattern favorably onto the photosensitive
`
`20
`
`substrate.
`
`[0040]
`
`Further, according to the exposure method as set forth in Claim
`
`17, the exposure method comprises an illumination step of illuminating
`a mask onto which a predetermined pattern is formed, and an exposure
`
`25
`
`step of exposing a pattern of the mask disposed on the first surface onto
`
`a photosensitive substrate disposed on the second surface, using the
`
`19
`
`22
`
`22
`
`
`
`JP2003—350647
`
`catadioptric projection optical system according to any one of Claims 1
`
`to 15.
`
`[0041]
`
`Since
`
`it
`
`exposes with an aligner
`
`including catadioptric
`
`projection optical systems with large compact and numerical aperture
`
`according to this exposure approach according to claim 17, a detailed
`
`pattern can be exposed good.
`
`[Merit of the Invention]
`
`[0042]
`
`10
`
`According to the reflective refi‘action projection optical system
`
`of this invention, since the medium image of the lst page is formed in
`
`the lst image formation optical system, when numerical aperture of a
`reflective refi'action projection optical system is enlarged, optical-path
`
`separation with the flux of light which goes to the lst page side, and the
`
`15
`
`flux of light which goes to the 2nd page side can be ensured and easily,
`
`-
`
`Moreover, since the 2nd image formation optical system is equipped
`
`with the lst lens group which has negative refractive power, adjustment
`
`for being able to shorten the overall length of a reflective refraction
`
`projection optical system, and satisfying Petzval's condition can be
`
`20
`
`performed easily. Furthermore, the lst lens group eases dispersion by
`
`the difference in the field angle of the flux of light which was able to be
`
`extended by the lst field mirror, and controls generating of aberration.
`Therefore, in order to make resolution high, when numerical aperture by
`
`the side of the body of a reflective refraction projection optical system
`
`25‘
`
`and an image is enlarged, the good image formation engine performance
`
`can be obtained throughout the inside of an exposure field.
`
`20
`
`23
`
`23
`
`
`
`JP2003—350647
`
`[0043]
`
`Moreover, according to the exposure apparatus of this invention, since it
`
`has a catadioptric projection optical system with large compact and
`
`numerical aperture, a detailed pattern can be exposed good on a
`
`photosensitive substrate.
`
`[0044]
`
`Moreover, according to the exposure method of the present invention,
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