Catadioptric projection objective with geometric beam splitting

Abstract

A projection exposure lens has an object plane, optical elements for separating beams, a concave mirror, an image plane, a first lens system arranged between the object plane and the optical elements for separating beams, a second double pass lens system arranged between the optical elements for separating beams and the concave mirror, a third lens system arranged between the optical elements for separating beams and the image plane. The second lens system has a maximum of five lenses.

1 . (canceled) 
     
     
         2 . A projection objective for projecting a mask pattern arranged in an object plane of the projection objective into an image plane of the projection objective, the projection objective comprising:
 a first concave mirror arranged in the vicinity of a first pupil plane of the projection objective;   a second concave mirror arranged in the vicinity of a second pupil plane of the projection objective;   a first folding mirror that reflects light from the object plane toward the first concave mirror;   a second folding mirror that reflects light from the second concave mirror toward the image plane; and   a lens arranged between the second folding mirror and the image plane.   
     
     
         3 . The projection objective of  claim 2 , wherein the lens is one of a plurality of lenses arranged between the second folding mirror and the image plane. 
     
     
         4 . The projection objective of  claim 2 , further comprising:
 a third folding mirror that reflects light from the first concave mirror; and   a fourth folding mirror that reflects light from the third folding mirror toward the second concave mirror.   
     
     
         5 . The projection objective of  claim 2 , wherein the projection objective has a magnification not equal to one. 
     
     
         6 . The projection objective of  claim 2 , wherein an odd number of intermediate images are formed in the projection objective. 
     
     
         7 . The projection objective of  claim 6 , wherein exactly three intermediate images are formed in the projection objective. 
     
     
         8 . The projection objective of  claim 6 , wherein a sum of the number of intermediate images and a number of mirrors in the projection objective is an odd whole number. 
     
     
         9 . The projection objective of  claim 2 , further comprising a first negative lens that is arranged in front of the first concave mirror at a distance therefrom. 
     
     
         10 . The projection objective of  claim 9 , wherein no optical element is arranged between the first negative lens and the first concave mirror. 
     
     
         11 . The projection objective of  claim 9 , further comprising a second negative lens that is arranged in front of the second concave mirror at a distance therefrom. 
     
     
         12 . The projection objective of  claim 11 , wherein no optical element is arranged between the second negative lens and the second concave mirror. 
     
     
         13 . The projection objective of  claim 2 , wherein the image plane is arranged at an element for a liquid crystal display. 
     
     
         14 . A projection objective for projecting a mask pattern arranged in an object plane of the projection objective into an image plane of the projection objective, the projection objective comprising:
 a first concave mirror arranged in the vicinity of a first pupil plane of the projection objective;   a second concave mirror arranged in the vicinity of a second pupil plane of the projection objective;   a first folding mirror that reflects light from the object plane toward the first concave mirror;   a second folding mirror that reflects light from the second concave mirror toward the image plane; and   a lens arranged between the object plane and the first folding mirror.   
     
     
         15 . The projection objective of  claim 14 , wherein the lens is one of a plurality of lenses arranged between the object plane and the first folding mirror. 
     
     
         16 . A projection objective for projecting a mask pattern arranged in an object plane of the projection objective into an image plane of the projection objective, the projection objective comprising:
 a first concave mirror arranged in the vicinity of a first pupil plane of the projection objective;   a second concave mirror arranged in the vicinity of a second pupil plane of the projection objective;   a first folding mirror that reflects light from the object plane toward the first concave mirror; and   a second folding mirror that reflects light from the second concave mirror toward the image plane;   wherein an image-side numerical aperture of the projection objective is greater than 0.7.   
     
     
         17 . The projection objective of  claim 16 , wherein the image-side numerical aperture of the projection objective is not less than 1.0.