Illumination apparatus

Abstract

The present invention aims to offer a compact illumination apparatus with a simple structure that can reduce an ununiformity of the Gaussian intensity distribution due to a laser beam and an interference noise due to an optical integrator at the same time. The present invention secondarily aims to offer a projection and exposure apparatus that uses said illumination apparatus and an exposing method. In order to eliminate disadvantages as described above, the present invention offers an illumination apparatus that illuminates a mask with a predetermined pattern formed characterized in that said apparatus comprises the following components: a light source that supplies a light beam; a multi-beam forming optical system that consists of a reflecting member and a light splitting member and converts said light beam from said light source into a group of multiple beams; an optical integrator that splits said light from said light source and forms multiple light source images. As for said multi-beam forming optical system, said light splitting member is provided at a predetermined angle with respect to said reflecting member; and forms a group of multiple beams by repeatedly reflecting said light beam from said light source between said reflecting member and said light splitting member.

What is claimed:  
     
         1 . An illumination apparatus that illuminates a mask with a predetermined pattern formed, comprising: 
 a light source that supplies a light beam;    a multi-beam forming optical system that includes a reflecting member and a light splitting member and that converts a light beam from said light source into a group of multiple beams;    an optical integrator that divides a light from said light source and that forms multiple light source images, wherein said multi-beam forming optical system forms a group of multiple beams by, providing said light splitting member such that said light splitting member faces said reflecting member at a predetermined angle; and    repeatedly reflecting the beam from said light source between said reflecting member and said light splitting member.    
     
     
         2 . An illumination apparatus according to  claim 1 , wherein said predetermined angle is determined such that the reflected light returns to the incident direction after a predetermined number of reflections.  
     
     
         3 . An illumination apparatus according to  claim 1 , wherein said multi-beam forming optical system is structured such that the difference in length of light passages of two adjacent beams within the group of said multiple beams is adjusted to be the coherence length determined by the time coherence of said light source or longer.  
     
     
         4 . An illumination apparatus according to  claim 1  further comprising: 
 a condenser optical system that guides a light that passes through said optical integrator to said mask.  
 
     
     
         5 . An illumination apparatus according to  claim 1  further comprising: 
 a dispersion section that disperses the diameter of each beam such that said diameter becomes larger than that of an element lens of said optical integrator on the incident surface of said optical integrator.  
 
     
     
         6 . An illumination apparatus according to  claim 1  further comprising: 
 a relay lens system provided between said dispersion section and said optical integrator.  
 
     
     
         7 . An illumination apparatus according to  claim 2 , wherein said multi-beam forming optical system is structured such that the difference in length of light passages of two adjacent beams within the group of said multiple beams is adjusted to be the coherence length determined by the time coherence of said light source or longer.  
     
     
         8 . An illumination apparatus according to  claim 7  further comprising: 
 a condenser optical system that guides the light which passes through said optical integrator to said mask.  
 
     
     
         9 . An illumination apparatus according to  claim 8  further comprising: 
 a dispersion section that disperses the diameter of each beam such that said diameter becomes larger than that of the element lens of said optical integrator on the incident surface of said optical integrator.  
 
     
     
         10 . An illumination apparatus according to  claim 9  further comprising: 
 a relay lens system provided between said dispersion section and said optical integrator.  
 
     
     
         11 . A projection and exposure apparatus, comprising: 
 a first stage that holds said mask;    an illumination apparatus that illuminates said mask, as recited in  claim 1;     a second stage that holds a substrate to be exposed; and    a projection optical system that projects and exposes a pattern image of said mask illuminated by using said illumination apparatus onto said substrate to be exposed.    
     
     
         12 . A projection and exposure apparatus according to  claim 11 , wherein the projection and exposure apparatus is as a scanning projection and exposure apparatus in which at least one of said mask and said substrate to be exposed relatively moves, and the scanning direction on said substrate to be exposed and the direction in which said group of multiple beams are arranged are substantially equivalent.  
     
     
         13 . An exposure method, comprising: 
 using said illumination apparatus as recited in  claim 1;     illuminating said mask provided onto the object surface; and    projecting a pattern image of said mask onto a photosensitive substrate provided onto the surface of the last image.