Projection exposure apparatus

Abstract

A high-performance projection exposure apparatus excellent in durability and reproducibility, which can adjust optical characteristics which are rotationally asymmetric with respect to the optical axis of projection optical system and which remain in the projection optical system. The projection exposure apparatus comprises an illumination optical system, a projection optical system and an optical means. The illumination optical system illuminate a first object, and the projection optical system projects an image of the first object onto a second object under a predetermined magnification. The optical means is set between the first object and the second object, and has rotationally asymmetric powers with respect to an optical axis of the projection optical system. Consequently, the optical means can correct an optical characteristic rotationally asymmetric with respect to the optical axis of the projection optical system, remaining in the projection optical system.

What is claimed is:  
     
         1 . A projection exposure apparatus comprising: 
 an illumination optical system for illuminating a first object;    a projection optical system for projecting an image of said first object illuminated by said illumination optical system onto a second object under a predetermined magnification; and    an optical means set between said first object and said second object, having rotationally asymmetric powers with respect to an optical axis of said projection optical system, for correcting an optical characteristic rotationally asymmetric with respect to the optical axis of said projection optical system, remaining in said projection optical system.    
     
     
         2 . A projection exposure apparatus according to  claim 1 , wherein said optical means is arranged as rotatable about the optical axis of said projection optical system.  
     
     
         3 . A projection exposure apparatus according to  claim 1 , wherein said optical means is arranged as movable along the optical axis of said projection optical system.  
     
     
         4 . A projection exposure apparatus according to  claim 1 , wherein said optical means comprises a toric optical member having different powers in orthogonal directions.  
     
     
         5 . A projection exposure apparatus according to  claim 4 , wherein said toric optical member comprises first and second toric optical elements each having different powers in orthogonal directions, 
 wherein said first and second toric optical elements are arranged as relatively rotatable about the optical axis of said projection optical system.    
     
     
         6 . A projection exposure apparatus according to  claim 4 , wherein said toric optical member comprises first and second toric optical elements each having different powers in orthogonal directions, 
 wherein said first and second toric optical elements are arranged as relatively movable along the optical axis of said projection optical system.    
     
     
         7 . A projection exposure apparatus according to  claim 1 , wherein said optical means is set either between said first object and said projection optical system, inside said projection optical system, or between said projection optical system and said second object.  
     
     
         8 . A projection exposure apparatus according to  claim 1 , wherein said optical means is set at or near the pupil plane of said projection optical system.  
     
     
         9 . A projection exposure apparatus according to  claim 1 , wherein said first object is a reticle a pattern to be projected is formed thereon.  
     
     
         10 . A projection exposure apparatus according to  claim 1 , wherein said second object is a semiconductor wafer.  
     
     
         11 . A projection exposure apparatus comprising: 
 an illumination optical system for illuminating a first object; and    a projection optical system for projecting an image of said first object illuminated by said illumination optical system onto a second object under a predetermined magnification;    wherein said projection optical system comprises a lens, the surface thereof contributes to imaging performance of said projection optical system and has a rotationally asymmetric region having rotationally asymmetric powers with respect to the optical axis of said projection optical system, in order to correct an optical characteristic rotationally asymmetric with respect to the optical axis of said projection optical system.    
     
     
         12 . A projection exposure apparatus according to  claim 11 , wherein said lens is arranged as rotatable about the optical axis of said projection optical system.  
     
     
         13 . A projection exposure apparatus according to  claim 11 , wherein said lens is arranged as movable along the optical axis of said projection optical system.  
     
     
         14 . A projection exposure apparatus according to  claim 11 , wherein said lens comprises first and second lens elements each having different powers in orthogonal directions.  
     
     
         15 . A projection exposure-apparatus according to,  claim 11 , wherein said first object is a reticle a pattern to be projected is formed thereon.  
     
     
         16 . A projection exposure apparatus according to  claim 11 , wherein said second object is a semiconductor wafer.