Illumination optical system, exposure apparatus, and article manufacturing method

Abstract

An illumination optical system of the present invention includes a first lens array FE including a plurality of lens cells dividing a light flux emitted from a light source into a plurality of light fluxes, a second lens array MLAi including lens cells on which spot lights exiting from the lens cells included in the first lens array FE are condensed, and a first optical member IL3 imaging the spot light, which has been condensed on the lens cell included in the second lens array MLAi, on one of optical modulation elements constituting an optical modulation unit.

What is claimed is: 
     
         1 . An illumination optical system illuminating an optical modulation unit including a plurality of optical modulation elements with a light flux emitted from a light source, the illumination optical system comprising:
 a first lens array including a plurality of lens cells dividing the light flux emitted from the light source into a plurality of light fluxes;   a second lens array including lens cells on which spot lights exiting from the lens cells included in the first lens array are condensed; and   a first optical member imaging the spot light, which has been condensed on the lens cell included in the second lens array, on one of the optical modulation elements constituting the optical modulation unit,   wherein the second lens array and the optical modulation unit are in a conjugate relation via the first optical member.   
     
     
         2 . The illumination optical system according to  claim 1 , wherein the second lens array and the optical modulation unit are arranged in a relation of a critical illumination. 
     
     
         3 . The illumination optical system according to  claim 1 , wherein the second lens array is constituted by a field lens and an imaging lens, the imaging lens being located at a position away from the field lens through a focal length of the field lens. 
     
     
         4 . The illumination optical system according to  claim 3 , further comprising a second optical member arranged between the first lens array and the second lens array,
 wherein a focal length of the second optical member is longer than the focal length of the field lens.   
     
     
         5 . The illumination optical system according to  claim 1 , further comprising a second optical member arranged between the first lens array and the second lens array,
 wherein the first lens array is arranged such that an exit surface of the first lens array is positioned in a front-side focal plane of the second optical member, and   wherein the second lens array is arranged such that an incident surface of the second lens array is positioned in a rear-side focal plane of the second optical member.   
     
     
         6 . The illumination optical system according to  claim 1 , wherein the plurality of spot lights exiting from the plurality of lens cells included in the first lens array is condensed on the lens cell included in the second lens array. 
     
     
         7 . The illumination optical system according to  claim 6 , wherein the first optical member images the plurality of spot lights, which have been condensed on the lens cell included in the second lens array, on one of the optical modulation elements constituting the optical modulation unit. 
     
     
         8 . An illumination optical system illuminating an optical modulation unit including a plurality of optical modulation elements with a light flux emitted from a light source, the illumination optical system comprising:
 a lens array including a plurality of lens cells dividing the light flux emitted from the light source into a plurality of light fluxes;   a light-shielding member illuminated by the lens array and including a plurality of openings; and   a first optical member imaging the spot light, which have passed through the opening of the light-shielding member, on one of the optical modulation elements constituting the optical modulation unit,   wherein the light-shielding member and the optical modulation unit are in a conjugate relation via the first optical member.   
     
     
         9 . The illumination optical system according to  claim 8 , wherein the light-shielding member and the optical modulation unit are arranged in a relation of a critical illumination. 
     
     
         10 . The illumination optical system according to  claim 8 , further comprising a second optical member arranged between the lens array and the light-shielding member,
 wherein the lens array is arranged such that an exit surface of the lens array is positioned in a front-side focal plane of the second optical member, and   wherein the light-shielding member is arranged such that an incident surface of the light-shielding member is positioned in a rear-side focal plane of the second optical member.   
     
     
         11 . The illumination optical system according to  claim 8 , wherein the light-shielding member is made of metal. 
     
     
         12 . An illumination optical system illuminating an optical modulation unit including a plurality of optical modulation elements with a light flux emitted from a light source, the illumination optical system comprising:
 an integrator making a light intensity distribution of the light flux emitted from the light source be uniform;   a lens array including lens cells on which a light flux having passed through the integrator is condensed; and   an optical member imaging the light flux, which has been condensed on the lens cell, on one of the optical modulation elements constituting the optical modulation unit,   wherein the lens array and the optical modulation unit are in a conjugate relation via the first optical member.   
     
     
         13 . The illumination optical system according to  claim 12 , wherein the lens array and the optical modulation unit are arranged in a relation of a critical illumination. 
     
     
         14 . An exposure apparatus comprising:
 the illumination optical system according to  claim 1 , the illumination optical system illuminating an optical modulation unit including a plurality of optical modulation elements with light; and   a projection optical system projecting light from the optical modulation unit on a substrate.   
     
     
         15 . The exposure apparatus according to  claim 14 , wherein the optical modulation unit is a micromirror device including a plurality of two-dimensionally arrayed micromirrors, each of the micromirrors having a reflective surface which reflects a light flux from the illumination optical system and an angle of the reflective surface being able to be changed. 
     
     
         16 . The exposure apparatus according to  claim 14 , further comprising a polarizing beam splitter and a phase plate that are arranged between the illumination optical system and the optical modulation unit. 
     
     
         17 . The exposure apparatus according to  claim 16 , wherein the light flux from the illumination optical system is converted to circular polarized light through the polarizing beam splitter and the phase plate, and the circular polarized light is incident on the projection optical system. 
     
     
         18 . An exposure apparatus comprising:
 the illumination optical system according to  claim 8 , the illumination optical system illuminating an optical modulation unit including a plurality of optical modulation elements with light; and   a projection optical system projecting light from the optical modulation unit on a substrate.   
     
     
         19 . An exposure apparatus comprising:
 the illumination optical system according to  claim 12 , the illumination optical system illuminating an optical modulation unit including a plurality of optical modulation elements with light; and   a projection optical system projecting light from the optical modulation unit on a substrate.   
     
     
         20 . An article manufacturing method comprising steps of:
 performing exposure on a substrate by using the exposure apparatus according to  claim 14 ; and   developing the substrate that has been subjected to the exposure in the exposure step.