Projection optical system and exposure apparatus having the projection optical system

Abstract

A projection optical system according to the present invention whose image side numerical aperture is greater than or equal to 0.75, and which forms an image of a first object upon a second object using light of a predetermined wavelength less than or equal to 300 nm, comprises: a first lens group G 1 of positive refractive power; a second lens group G 2 of negative refractive power; a third lens group G 3 of positive refractive power; and a fourth lens group G 4 of positive refractive power, and: the first lens group G 1 , the second lens group G 2 , the third lens group G 3 and the fourth lens group G 4 are arranged in order from a side of the first object; and a distance D in mm along an optical axis between an optical surface of the fourth lens group G 4 closest to the second object, and the second object, satisfies a condition of 0.1<D<5.

1 . A projection optical system which forms an image of a first object upon a second object, comprising: 
 plural optical lens elements, the plural optical lens elements include a most second object side lens element,    wherein the most second object side lens element is a nearest lens element to the second object among the plural optical lens elements belonging to the projection optical system, and is a most thick lens element among the plural optical lens elements belonging to the projection optical system.    
   
   
       2 - 4 . (Cancelled)  
   
   
       5 . The projection optical system according to  claim 1 , wherein the projection optical system satisfies a condition of 0.1<D<5, 
 where D is a distance in mm along an optical axis between an optical surface closest to the second object and the second object.    
   
   
       6 . The projection optical system according to  claim 5 , wherein the plural optical lens elements comprise: 
 a first lens group, arranged in an optical path between the first object and the second object, having a negative power;    a second lens group, arranged in an optical path between the first lens group and the second object, having a positive power;    a third lens group, arranged in an optical path between the second lens group and the second object, having a negative power;    a fourth lens group, arranged in an optical path between the third lens group and the second object, having a positive power; and    a fifth lens group, arranged in an optical path between the fourth lens group and the second object, having a positive power.    
   
   
       7 . The projection optical system according to  claim 6 , wherein, with T being a sum of thicknesses along the optical axis of all lens elements included in the fifth lens group, and with D being the distance along the optical axis between an optical surface of the fifth lens group closest to the second object, and the second object, a condition of 0.001<D/T<0.2 is satisfied.  
   
   
       8 . The projection optical system according to  claim 7 , wherein a condition of 0.02<T/L is satisfied, where L is a distance along the optical axis between the first object and the second object.  
   
   
       9 . The projection optical system according to  claim 8 , wherein the distance L in mm satisfies a condition of 800<L<1600.  
   
   
       10 . The projection optical system according to  claim 9 , wherein a space between the optical surface closest to the second object and the second object is filled with a liquid.  
   
   
       11 . The projection optical system according to  claim 9 , wherein a space between the optical surface closest to the second object and the second object is filled with a gas.  
   
   
       12 . The projection optical system according to  claim 9 , wherein at least one of a plurality of optical surfaces of the plural optical lens elements of the projection optical system is formed in an aspherical shape.  
   
   
       13 . The projection optical system according to  claim 6 , wherein a focal length F2 of the second lens group and a distance L in mm along the optical axis between the first object and the second object satisfy a condition of 0.01<|F2|/L<0.15.  
   
   
       14 . An exposure apparatus comprising: 
 an illumination system which is arranged in an optical path between a light source and a mask as a first object and which illuminates the mask based on a light from the light source; and    the projection optical system according to  claim 1 , that forms an image of a pattern which is formed upon the mask upon a photosensitive substrate as the second object.    
   
   
       15 . The exposure apparatus according to  claim 14 , further comprising a flow device which is arranged near an optical path between the optical surface closest to the second object and the photosensitive substrate, and which forms a predetermined flow of fluid in the optical path between the optical surface closest to the second object and the photosensitive substrate.  
   
   
       16 . The exposure apparatus according to  claim 15 , wherein a space between the optical surface closest to the second object and the second object is filled with a liquid.  
   
   
       17 . An exposure method, comprising: 
 illuminating a mask as a first object; and    exposing via the projection optical system according to  claim 1 , an image of a pattern which is formed upon the mask upon a photosensitive substrate as the second object.    
   
   
       18 . An exposure method according to  claim 17 , wherein the exposing step comprises a flow formation process of forming a predetermined fluid flow in an optical path between the optical surface closest to the second object and the photosensitive substrate.  
   
   
       19 . The projection optical system according to  claim 1 , wherein a space between an optical surface closest to the second object and the second object is filled with a liquid.  
   
   
       20 . The projection optical system according to  claim 5 , wherein a space between the optical surface closest to the second object and the second object is filled with a liquid.