Illumination optical apparatus and exposure apparatus

Abstract

An illumination optical apparatus ( 14 - 40 ) and exposure apparatus ( 10 ) provided with the illumination apparatus, capable of employing a high-output light source. The illumination apparatus comprises, in order along an optical axis, a light source ( 14 ) capable of providing a primary light beam (B) having a cross-section, a condenser optical system ( 30 ) to condense the primary light beam so as to form a convergence point (F) adjacent the condenser optical system, a light-pipe optical integrator ( 160 ) having a rectangular cross-sectional shape with a first side of length dx, a second side of length dy, and a most light-source-wise incident surface ( 160 a ) axially spaced from the convergence point by a spacing (L 2 ). The integrator is capable of forming a plurality of secondary light sources and corresponding secondary light beams (B′) from the primary light beam. Adjacent the integrator is an imaging optical system ( 40 ) to converge the primary and secondary light beams to illuminate the illumination surface. The apparatus preferably satisfies the following conditions: 0.1 ≦L 2 ≦dx /( 2 ×tan α x ) 0.1 ≦L 2 ≦dy /( 2 ×tan α y ), wherein αx is the divergence angle of the primary light beam when incident the integrator incident surface, as measured in a first plane that includes the optical axis. Likewise, αy is the corresponding angle as measured in a second plane orthogonal to the first plane. These conditions ensure that the integrator will not be damaged or otherwise broken by high concentrations of light on the integrator incident surface. The exposure apparatus comprises the above-described illumination optical system and further includes a projection optical system ( 54 ) arranged adjacent the illumination surface so as to project an image of a pattern on a mask ( 48 ) onto a photosensitive substrate ( 60 ), thereby patterning the substrate.

What is claimed is:  
     
         1 . An illumination optical apparatus for illuminating an illumination surface, comprising, in order along an optical axis: 
 a) a light source capable of providing a primary light beam having a cross-section;    b) a condenser optical system to condense said primary light beam so as to form a convergence point adjacent said condenser optical system;    c) a light-pipe optical integrator having a rectangular cross-sectional shape with a first side of length dx, a second side of length dy, and a most light-source-wise incident surface axially spaced from said convergence point by a spacing L, said integrator capable of forming a plurality of secondary light sources and corresponding secondary light beams from said primary light beam;    d) an imaging optical system to converge said primary and secondary light beams to illuminate the illumination surface; and    e) wherein the following conditions are satisfied:   0.1 ≦L≦dx /(2×tan α x )0.1 ≦L≦dy /(2×tan α y ),   wherein αx is an angle of said primary light beam incident said incident surface, as measured in a first plane that includes the optical axis, and αy is an angle of said primary light beam incident said incident surface, as measured in a second plane orthogonal to said first plane.    
     
     
         2 . An illumination optical apparatus according to  claim 1 , further including first and second variable optical members, arranged between said light source and said light pipe optical integrator, capable of shaping said primary light beam cross-section so as to make said light beam cross-section and said light pipe optical integrator cross-sectional shape substantially similar.  
     
     
         3 . An illumination optical apparatus according to  claim 2 , wherein said condenser optical system has a variable focal length to allow a change in said at least one of angles αx and ay while maintaining said convergence point at a fixed position.  
     
     
         4 . An illumination optical apparatus according to  claim 1 , further including first and second variable optical members capable of shaping said light beam cross-section.  
     
     
         5 . An illumination optical apparatus according to  claim 4 , wherein said first and second variable optical members are capable of being arranged so as to shape said light beam cross-section to form an annular light source.  
     
     
         6 . An illumination optical apparatus according to  claim 4 , wherein said first and second variable optical members are capable of being arranged so as to shape said light beam cross-section to form a plurality of light sources eccentric to the optical axis.  
     
     
         7 . An illumination optical apparatus according to  claim 4 , wherein said first variable optical member comprises, in order along the optical axis: 
 a) a first conical prism with a most light-source-wise planar surface and an opposing conical concave surface symmetric with respect to the optical axis;    b) a second conical prism with a most light-source-wise conical convex surface symmetric with respect to the optical axis, and an opposing planar surface; and    c) wherein at least one of said first conical prism and said second conical prism is designed so as to be moveable along the optical axis.    
     
     
         8 . An illumination optical apparatus according to  claim 7 , wherein said second variable optical member comprises, in order along the optical axis: 
 a) a first pyramidal prism with a most light-source-wise planar surface and an opposing pyramidal concave surface symmetric with respect to the optical axis;    b) a second pyramidal prism with a most light-source-wise pyramidal convex surface symmetric with respect to the optical axis, and an opposing planar surface; and    c) wherein at least one of said first pyramidal prism and said second pyramidal prism is designed so as to be moveable along the optical axis.    
     
     
         9 . An illumination optical apparatus, comprising in order along an optical axis: 
 a) a light source capable of supplying a primary light beam having a first cross-section;    b) a condenser optical system capable of condensing said light beam;    c) a light pipe optical integrator having a most light-source-wise incident surface with an incident surface shape, and capable of forming, from said primary light beam, a plurality of secondary light sources and associated secondary light beams;    d) an imaging optical system designed to converge said secondary light beams to illuminate the surface to be irradiated; and    e) a light beam shaping apparatus designed to shape said light beam first cross-section to form a second light-beam cross-section having a shape substantially similar to said light pipe incident surface shape.    
     
     
         10 . An illumination optical apparatus according to  claim 9 , wherein said condenser optical system is capable of forming a convergence point spaced apart from said light pipe incident surface by spacing L.  
     
     
         11 . An illumination optical apparatus according to  claim 10 , wherein said spacing L satisfied the conditions: 
       0.1 ≦L≦dx /(2×tan α x )0.1 ≦L≦dy /(2×tan α y ), 
       wherein αx is an angle in said primary light beam incident said incident surface, as measured in a first plane that includes the optical axis, and αy is an angle in said incident light beam incident said incident surface, as measured in a second plane orthogonal to said first plane.  
     
     
         12 . An exposure apparatus for patterning a photosensitive substrate with pattern present on a mask, comprising in order along an optical axis: 
 a) an illumination optical system as set forth in  claim 1;  and    b) a projection optical system arranged adjacent the illumination surface, with the mask arranged at the illumination surface, so as to project the mask pattern onto the photosensitive substrate.    
     
     
         13 . An exposure apparatus for exposing a pattern present on a mask onto a photosensitive substrate, comprising in order along an optical axis: 
 a) an illumination optical system as set forth in  claim 9;  and    b) a projection optical system arranged adjacent the illumination surface, with the mask arranged at the illumination surface, so as to project the mask pattern onto the photosensitive substrate.    
     
     
         14 . A method of uniformly illuminating a surface with an illumination optical apparatus having a light pipe optical integrator with an integrator cross-section, an incident surface and an exit surface, comprising the steps of: 
 a) providing a primary light beam having a primary light beam cross-section;    b) condensing said primary light beam and forming a convergence point at a position spaced apart from said incident surface;    c) collecting light emanating from said convergence point at an angle α using said light pipe optical integrator;    d) forming a plurality of secondary light sources and associated secondary light beams by multiply internally reflecting said light within said light pipe optical integrator; and    e) converging said primary and secondary light beams emanating from said exit surface to uniformly illuminate the illumination surface.    
     
     
         15 . A method-according to  claim 14 , wherein said condensing step b) further includes the step of varying said angle α while maintaining said convergence point at a fixed position.  
     
     
         16 . A method according to  claim 14 , further including the step after said step a) but before said step b), of varying said primary light beam cross-section to be substantially similar in size and shape to said integrator cross-section.  
     
     
         17 . A method of patterning a photosensitive substrate by uniformly illuminating a mask having a pattern thereon with an exposure apparatus including a light pipe optical integrator having an integrator cross-section, an incident surface and an exit surface, comprising the steps of: 
 a) providing a primary light beam having a primary light beam cross-section;    b) condensing said primary light beam and forming a convergence point at a position spaced apart from said incident surface;    c) collecting light emanating from said convergence point at an angle α using said light pipe optical integrator;    d) forming a plurality of secondary light sources and associated secondary light beams by multiply internally reflecting said light within said light pipe optical integrator;    e) converging said primary and secondary light beams emanating from said exit surface to uniformly illuminate the mask; and    f) projecting an image of the mask onto the photosensitive substrate so as to form a pattern thereon.    
     
     
         18 . A method according to  claim 17 , wherein said condensing step b) further includes the step of varying said angle α while maintaining said convergence point at a fixed position.  
     
     
         19 . A method according to  claim 17 , further including the step after said step a) but before said step b), of varying said primary light beam cross-section to be substantially similar in size and shape to said integrator cross-section.  
     
     
         20 . An exposure apparatus for patterning a photosensitive substrate with a pattern formed on a mask, comprising: 
 an illumination optical system for illuminating the mask; and    a projection optical system arranged in an optical path between the mask and the photosensitive substrate, so as to project an image of the pattern formed on the mask onto the photosensitive substrate;    wherein said illumination optical system comprises:    a light source unit for providing a light beam;    an integrator disposed in the optical path between said light source unit and the mask; and    a light beam shape changing system comprising a first optical system disposed in an optical path between said light source unit and said integrator so as to change the light beam into an annular light beam having an annular cross-sectional shape and vary the annular cross-sectional shape continuously, and a second optical system disposed in the optical path between said light source unit and said integrator so as to change the light beam into a multi-pole light beam having a multi-pole cross-sectional shape and vary the multi-pole cross-sectional shape continuously.    
     
     
         21 . An exposure apparatus according to  claim 20 , wherein said illumination optical system further comprises a changing system disposed in the optical path between said light source unit and said integrator so as to change a numerical aperture of a light beam entering said integrator.  
     
     
         22 . An exposure apparatus according to  claim 20 , wherein said illumination optical system further comprises an energy reducing system disposed in the optical path between said light source unit and said integrator so as to reduce an intensive energy with respect to said integrator.  
     
     
         23 . An exposure apparatus according to  claim 22 , wherein said energy reducing system forms a convergence point spaced from an incident surface of said integrator so as to prevent said integrator from being damaged.  
     
     
         24 . An exposure apparatus according to  claim 22 , wherein said energy reducing system comprises a changing system disposed in the optical path between said light source unit and said integrator so as to change a numerical aperture of a light beam entering said integrator.  
     
     
         25 . An exposure apparatus according to  claim 20 , wherein said integrator comprises an internal reflection-type integrator that has an axial length Lin≦1500 mm.  
     
     
         26 . An exposure apparatus according to  claim 21 , wherein said integrator comprises an internal reflection-type integrator that has an axial length Lin≦1500 mm.  
     
     
         27 . An exposure apparatus according to  claim 22 , wherein said integrator comprises an internal reflection-type integrator that has an axial length Lin≦1500 mm.  
     
     
         28 . An exposure apparatus according to  claim 24 , wherein said integrator comprises an internal reflection-type integrator that has an axial length Lin≦1500 mm.  
     
     
         29 . An exposure apparatus according to  claim 20 , wherein said integrator comprises an internal reflection-type integrator made from fluorite.  
     
     
         30 . An exposure apparatus according to  claim 21 , wherein said integrator comprises an internal reflection-type integrator made from fluorite.  
     
     
         31 . An exposure apparatus according to  claim 22 , wherein said integrator comprises an internal reflection-type integrator made from fluorite.  
     
     
         32 . A method of manufacturing a semiconductor device, comprising the steps of: 
 providing a light beam;    adjusting the light beam by using at least one of a beam changing system including a first sub-changing system that changes the light beam into an annular light beam having an annular cross-sectional shape and varies the annular cross-sectional shape continuously, and a second sub-changing system that changes the light beam into a multi-pole light beam having a multi-pole cross-sectional shape and varies the multi-pole cross-sectional shape continuously;    guiding the adjusted light beam to an integrator;    directing the light beam that has passed through said integrator to a mask; and    projecting an image of a pattern formed on the mask onto a photosensitive substrate.    
     
     
         33 . A method according to  claim 32 , wherein said adjusting step further comprises the step of changing a numerical aperture of a light beam entering said integrator by using a changing system disposed in an optical path between a light source unit that provides said light beam and said integrator.  
     
     
         34 . A method according to  claim 32 , wherein said adjusting step further comprises the step of reducing an intensive energy with respect to said integrator by using an energy reducing system disposed in an optical path between a light source unit that provides said light beam and said integrator.  
     
     
         35 . A method according to  claim 34 , wherein the reducing step includes the step of forming a convergence point spaced from an incident surface of said integrator so as to prevent said integrator from being damaged by using said energy reducing system.  
     
     
         36 . A method according to  claim 34 , wherein the reducing step comprises the step of changing a numerical aperture of a light beam entering said integrator by using a changing system disposed in the optical path between said light source unit and said integrator so as to change a numerical aperture of a light beam entering said integrator.  
     
     
         37 . A method according to  claim 32 , wherein said integrator comprises an internal reflection-type integrator that has an axial length Lin≦1500 mm.  
     
     
         38 . A method according to  claim 33 , wherein said integrator comprises an internal reflection-type integrator that has an axial length Lin≦1500 mm.  
     
     
         39 . A method according to  claim 34 , wherein said integrator comprises an internal reflection-type integrator that has an axial length Lin≦1500 mm.  
     
     
         40 . A method according to  claim 36 , wherein said integrator comprises an internal reflection-type integrator that has an axial length Lin≦1500 mm.  
     
     
         41 . A method according to  claim 32 , wherein said integrator comprises an internal reflection-type integrator made from fluorite.  
     
     
         42 . A method according to  claim 33 , wherein said integrator comprises an internal reflection-type integrator made from fluorite.  
     
     
         43 . A method according to  claim 34 , wherein said integrator comprises an internal reflection-type integrator made from fluorite.  
     
     
         44 . A method of exposing a pattern formed on a mask onto a photosensitive substrate, comprising the steps of: 
 providing a light beam;    adjusting the light beam by using at least one of a first sub-changing system within a beam changing system that changes the light beam into an annular light beam having an annular cross-sectional shape and varies the annular cross-sectional shape continuously, and a second sub-changing system within said beam changing system that changes the light beam into a multi-pole light beam having a multi-pole cross-sectional shape and varies the multi-pole cross-sectional shape continuously;    guiding the adjusted light beam to an integrator;    directing the light beam that has passed through said integrator to the mask; and    projecting an image of a pattern formed on the mask onto the photosensitive substrate.    
     
     
         45 . A method according to  claim 44 , wherein said adjusting step further comprises the step of changing a numerical aperture of a light beam entering said integrator by using a changing system disposed in an optical path between a light source unit that provides said light beam and said integrator.  
     
     
         46 . A method according to  claim 44 , wherein said adjusting step further comprises the step of reducing an intensive energy with respect to said integrator by using an energy reducing system disposed in an optical path between a light source unit that provides said light beam and said integrator.  
     
     
         47 . An exposure apparatus for patterning a photosensitive substrate with a pattern formed on a mask, comprising: 
 an illumination optical system for illuminating the mask; and    a projection optical system arranged in an optical path between the mask and the photosensitive substrate, so as to project an image of the pattern formed on the mask onto the photosensitive substrate;    wherein said illumination optical system comprises:    a light source unit for providing a light beam;    an integrator disposed in the optical path between said light source unit and the mask; and    an energy reducing system disposed in the optical path between said light source unit and said integrator so as to reduce an intensive energy with respect to said integrator,    wherein said integrator comprises an internal reflection-type integrator made from fluorite.    
     
     
         48 . A method of manufacturing a semiconductor device, comprising the steps of: 
 providing a light beam;    guiding the light beam to an integrator that comprises an internal reflection-type integrator made from fluorite;    directing the light beam that has passed through said integrator to a mask; and    projecting an image of a pattern formed on the mask onto a photosensitive substrate,    wherein said guiding step comprises the step of reducing an intensive energy with respect to said integrator.    
     
     
         49 . A method of exposing a pattern formed on a mask onto a photosensitive substrate, comprising the steps of: 
 providing a light beam;    guiding the light beam to an integrator that comprises an internal reflection-type integrator made from fluorite;    directing the light beam that has passed through said integrator to a mask; and    projecting an image of a pattern formed on the mask onto a photosensitive substrate,    wherein said guiding step comprises the step of reducing an intensive energy with respect to said integrator.    
     
     
         50 . An exposure apparatus for patterning a photosensitive substrate with a pattern formed on a mask, comprising: 
 a light source;    an optical integrator;    an optical system arranged in an optical path between the light source and the optical integrator; and    a light guide optical system arranged in the optical path between the light source and the optical integrator;    wherein the optical system includes a first optical system disposed to change a light beam into an annular light beam with an annular cross-sectional shape, and a second optical system disposed to change the light beam into a multipole light beam with a multipole cross-sectional shape; and    wherein the light guide optical system includes a first optical element with a positive power, and a second optical element with a negative power.    
     
     
         51 . An exposure apparatus according to  claim 50 , wherein the optical integrator comprises an internal reflection-type integrator that has an axial length Lin≦1500 mm.  
     
     
         52 . An exposure apparatus according to  claim 51 , wherein the internal reflection-type integrator is made from fluorite.  
     
     
         53 . A method for exposing a pattern formed on a mask onto a photosensitive substrate, comprising the steps of: 
 providing a light beam;    adjusting the light beam by using at least one of a first optical system within an optical system that changes the light beam into an annular light beam with an annular cross-sectional shape, and a second optical system within the optical system that changes the light beam into a multipole light beam with a multipole cross-sectional shape;    guiding the light beam to an optical integrator;    directing the light beam that has passed through the optical integrator to the mask; and    projecting an image of a pattern formed on the mask onto the photosensitive substrate;    wherein the method further comprises: 
 directing the light beam to the optical integrator by using a light guide optical system that includes a first element with a positive power and a second element with a negative power.  
   
     
     
         54 . A method according to  claim 53 , wherein the optical integrator is an internal reflection-type integrator.  
     
     
         55 . A method according to  claim 54 , wherein the directing step is performed prior to the guiding step.  
     
     
         56 . An illumination system comprising: 
 a light source that provides a light beam;    a guiding optical system disposed in an optical path between the light source and a mask plane and directing the light beam to the mask plane; and    a converting system in the optical path between the light source and the guiding optical system;    wherein the converting system comprises a first optical system disposed in the optical path between the light source and the mask plane so as to change a size of the light beam continuously, a second optical system disposed in the optical path between the light source and the mask plane so as to convert the light beam into an annular light beam having an annular cross-sectional shape under high efficiency, and a third optical system disposed in the optical path between the light source and the mask plane so as to convert the light beam into a multipole light beam having a multipole cross-sectional shape under high efficiency and change a condition of the multipole light beam;    wherein the second optical system includes at least one movable optical element so as to change a condition of the annular light beam continuously.    
     
     
         57 . An illumination system according to  claim 56 , wherein the third optical system comprises at least one movable optical element so as to change the multipole light beam continuously.  
     
     
         58 . An illumination system according to  claim 57 , further comprising an integrator disposed in the optical path between the converting system and the guiding optical system, the integrator including a rectangular entrance surface having a long edge and a short edge.  
     
     
         59 . An illumination system according to  claim 58 , wherein the first optical system includes a variable focal length system to change an entrance angle of the light beam at the rectangular entrance surface of the integrator.  
     
     
         60 . An illumination system according to  claim 57 , wherein the first optical system includes a zoom expander to expand the light beam from the light source.  
     
     
         61 . An exposure apparatus comprising: 
 a light source that provides a light beam having a wavelength less than 200 nm;    an illumination system including a converting system in an optical path between the light source and a mask plane; and    a projection system disposed in an optical path between the mask plane and a substrate plane;    wherein the converting system comprises a first optical system disposed in the optical path between the light source and the mask plane so as to change a size of the light beam under high efficiency, a second optical system disposed in the optical path between the light source and the mask plane so as to convert the light beam into an annular light beam having an annular cross-sectional shape under high efficiency and change a condition of the annular light beam under high efficiency, and a third optical system disposed in the optical path between the light source and the mask plane so as to convert the light beam into a multipole light beam having a multipole cross-sectional shape under high efficiency and change a condition of the multipole light beam under high efficiency.    
     
     
         62 . An exposure apparatus according to  claim 61 , wherein the illumination system further includes an optical integrator disposed in the optical path between the converting system and the mask plane, and 
 wherein the illumination system forms a rectangular illumination field having a long edge and a short edge at the mask plane and the converting system changes an illumination distribution at a pupil of the illumination system without changing the illumination field.    
     
     
         63 . An exposure apparatus comprising: 
 a light source that provides a light beam;    a converting system disposed in an optical path between the light source and a mask plane;    an integrator disposed in an optical path between the converting system and the mask plane, and which has a rectangular cross-sectional shape having a long edge and a short edge; and    a projection system disposed in an optical path between the mask plane and a substrate plane;    wherein the converting system comprises a first optical system disposed in the optical path between the light source and the mask plane so as to convert the light beam into an annular light beam having an annular cross-sectional shape and change an annular ratio of the annular light beam, a second optical system disposed in the optical path between the light source and the mask plane so as to convert the light beam into a multipole light beam having a multipole cross-sectional shape and change a condition of the multipole light beam, and a third optical system disposed in the optical path between the light source and the mask plane so as to change an entrance angle of the light beam at an entrance surface of the integrator.    
     
     
         64 . An exposure apparatus comprising: 
 a light source that provides a light beam;    a beam expander disposed in an optical path between the light source and a mask plane;    a converting system disposed in the optical path between the beam expander and the mask plane;    an integrator disposed in an optical path between the converting system and the mask plane, and which has a rectangular cross-sectional shape having a long edge and a short edge; and    a projection system disposed in an optical path between the mask plane and a substrate plane;    wherein the long edge of the rectangular cross-sectional shape is disposed along a predetermined beam expanding direction; and    wherein the converting system comprises a first optical system disposed in the optical path between the light source and the mask plane so as to convert the light beam into an annular light beam having an annular cross-sectional shape under high efficiency and change an annular ratio of the annular light beam under high efficiency, a second optical system disposed in the optical path between the light source and the mask plane so as to convert the light beam into a multipole light beam having a multipole cross-sectional shape under high efficiency and change a condition of the multipole light beam under high efficiency, and a third optical system disposed in the optical path between the light source and the mask plane so as to change an entrance angle of the light beam at an entrance surface of the integrator under high efficiency.    
     
     
         65 . An exposure apparatus comprising: 
 a light source that provides a light beam;    a first axicon disposed in an optical path between the light source and a mask plane and having a first variable space;    a second axicon disposed in an optical path between the first axicon and the mask plane having a second variable space;    an integrator disposed in an optical path between the second axicon and the mask plane; and    a variable system disposed in the optical path between the light source and the mask plane so as to change an entrance angle of the light beam at an entrance surface of the integrator.    
     
     
         66 . An exposure apparatus according to  claim 65 , wherein at least one of the first axicon and the second axicon converts the light beam into a multipole light beam having a multipole cross-sectional shape and changes a condition of the multipole light beam continuously.  
     
     
         67 . An exposure apparatus comprising: 
 a light source that provides a light beam;    a converting system disposed in an optical path between the light source and a mask plane; and    a projection system disposed in an optical path between the mask plane and a substrate plane;    wherein the converting system comprises a converting unit disposed in the optical path between the light source and the mask plane so as to convert the light beam into a multipole light beam having a multipole cross-sectional shape under high efficiency and change a condition of the multipole light beam under high efficiency, a zoom optical system disposed in the optical path between the light source and the mask plane so as to change a size of the light beam under high efficiency, and a variable optical system disposed in the optical path between the light source and the mask plane so as to change a focal length of the variable optical system.    
     
     
         68 . An exposure apparatus according to  claim 67 , further comprising an integrator disposed in an optical path between the variable optical system and the mask plane, 
 wherein the zoom optical system includes a beam expander disposed in an optical path between the light source and converting unit, and the variable optical system includes a variable unit disposed in an optical path between the converting unit and the integrator so as to change an entrance angle of the light beam at an entrance surface of the integrator.    
     
     
         69 . An exposure apparatus according to  claim 67 , wherein the converting unit includes two pyramidal surfaces forming a variable space to change a condition of the multipole light beam continuously.  
     
     
         70 . An exposure apparatus comprising: 
 a light source that provides a light beam;    a converting system disposed in an optical path between the light source and a mask plane so as to convert the light beam into a multipole light beam having a multipole cross-sectional shape under high efficiency and change a condition of the multipole light beam under high efficiency;    a zoom optical system disposed in an optical path between the light source and the converting system so as to change a size of the light beam under high efficiency;    a variable optical system disposed in an optical path between the zoom optical system and the mask plane so as to change a focal length of the variable optical system; and    a projection system disposed in an optical path between the mask plane and a substrate plane.    
     
     
         71 . An exposure apparatus according to  claim 70 , wherein the converting system includes two pyramidal surfaces forming a variable space to change a condition of the multipole light beam continuously.  
     
     
         72 . An exposure apparatus comprising: 
 a light source that provides a light beam;    an input optical system disposed in an optical path between the light source and a mask plane;    an internal reflection type integrator disposed in an optical path between the input optical system and the mask plane, and which has a rectangular cross-sectional shape having a long edge and a short edge; and    a projection system disposed in an optical path between the mask plane and a substrate plane;    wherein the input optical system has an optical unit that allows for a cross-section of the integrator and a cross-section of an incident beam from the input optical system to be substantially similar.    
     
     
         73 . An exposure apparatus according to  claim 72 , wherein the optical unit of the input optical system includes a cylindrical expander.