Microlithography projection optical system and method for manufacturing a device

Abstract

In some embodiments, a catoptric microlithgraphy projection optical system includes a plurality of reflective optical elements arranged to image radiation from an object field in an object plane to an image field in an image plane. The image field can have a size of at least 1 mm×1 mm. This optical system can have an object-image shift (OIS) of about 75 mm or less. Metrology and testing can be easily implemented despite rotations of the optical system about a rotation axis. Such a catoptric microlithgraphy projection optical system can be implemented in a microlithography tool. Such a microlithography tool can be used to produce microstructured components.

1 . A system, comprising:
 a plurality of reflective elements configured to image radiation from an object field in an object plane of the system to an image field in an image plane of the system,   wherein:
 the system has an optical axis that is a common axis of rotational symmetry for each reflective element in the projection objective system;
     d=h (1− M ); 
 
 h is a distance of a central point of the object field from the optical axis in a direction perpendicular to the optical axis; 
 M is a magnification ratio of the optical system; 
 d is about 75 mm or less; 
 the image field has a size of at least 1 mm×1 mm; 
 the system is a catoptric microlithography projection optical system; and 
 the system has an image-side numerical aperture of about 0.2 or more. 
   
     
     
         2 . The system of  claim 1 , wherein the image-side numerical aperture of the system is more than 0.3. 
     
     
         3 . The system of  claim 1 , wherein:
 a path of the radiation through the system is characterized by chief rays;   for a meridional section of the optical system, a chief ray of a central field point has a maximum angle of incidence on a reflective surface of each of the plurality of reflective elements of θ degrees;   the image side numerical aperture of the optical system is more than 0.3; and   a ratio θ/NA is less than 68.   
     
     
         4 . The system of  claim 1 , wherein at least one of the plurality of reflective elements has a rotationally asymmetric surface positioned in a path of the radiation, and the rotationally asymmetric surface deviates from a best-fit rotationally symmetric surface by at least at one or more locations, where λ is the wavelength of the radiation. 
     
     
         5 . The system of  claim 4 , wherein the best-fit rotationally asymmetric surface deviates by about 0.1λ or less from a surface corresponding to the equation: 
       
         
           
             
               z 
               = 
               
                 
                   
                     cr 
                     2 
                   
                   
                     1 
                     + 
                     
                       
                         1 
                         - 
                         
                           
                             ( 
                             
                               1 
                               + 
                               k 
                             
                             ) 
                           
                            
                           
                             c 
                             2 
                           
                            
                           
                             r 
                             2 
                           
                         
                       
                     
                   
                 
                 + 
                 
                   
                     ∑ 
                     
                       j 
                       = 
                       2 
                     
                     α 
                   
                    
                   
                       
                   
                    
                   
                     
                       C 
                       j 
                     
                      
                     
                       x 
                       m 
                     
                      
                     
                       y 
                       n 
                     
                   
                 
               
             
           
         
         
           
             where 
           
         
         
           
             
               
                 j 
                 = 
                 
                   
                     
                       
                         
                           ( 
                           
                             m 
                             + 
                             n 
                           
                           ) 
                         
                         2 
                       
                       + 
                       m 
                       + 
                       
                         3 
                          
                         n 
                       
                     
                     2 
                   
                   + 
                   1 
                 
               
               , 
             
           
         
         z is the sag of the surface parallel to a Z-axis of a Cartesian co-ordinate system, x and y are co-ordinates along an X-axis and a Y-axis, respectively, of the Cartesian co-ordinate system, r 2 =x 2 +y 2 , m and n are natural numbers, c is the vertex curvature and k is the conical constant, C j  is the coefficient of the monomial x m y n , and α is an integer. 
       
     
     
         6 . The system of  claim 4 , wherein the rotationally asymmetric surface deviates from the best-fit rotationally symmetric surface by about 10λ or more at the one or more locations. 
     
     
         7 . (canceled) 
     
     
         8 . The system of  claim 1 , wherein the plurality of reflective elements define a meridional plane and the plurality of reflective elements are mirror symmetric with respect to the meridional plane. 
     
     
         9 . The system of  claim 1 , wherein the plurality of reflective elements comprises two elements that are reflective elements and that have rotationally asymmetric surfaces positioned in a path of the radiation. 
     
     
         10 . The system of  claim 1 , wherein the plurality of elements includes at most two reflective elements that have a positive chief ray angle magnification. 
     
     
         11 . The system of  claim 1 , wherein the plurality of elements includes at most one reflective element that has a positive chief ray angle magnification. 
     
     
         12 . The system of  claim 1 , wherein the system has a rectangular field at the image plane, and the rectangular field in each orthogonal direction has a minimum dimension of about 1 mm or more. 
     
     
         13 . The system of  claim 1 , wherein static distortion at the image field is about 10 nm or less. 
     
     
         14 . The system of  claim 1 , wherein wavefront error at the image field is about λ/14 or less, where λ is the wavelength of the radiation. 
     
     
         15 . (canceled) 
     
     
         16 . The system of  claim 1 , wherein chief rays are parallel to each other to within 0.05° at the object plane. 
     
     
         17 . The system of  claim 1 , wherein chief rays diverge from each other at the object plane. 
     
     
         18 . The system of  claim 1  wherein, for a meridional section of the system, chief rays have a maximum angle of incidence on a surface of each of the elements of less than 20°. 
     
     
         19 . (canceled) 
     
     
         20 . The system of  claim 1 , wherein the system is telecentric at the image plane. 
     
     
         21 . The system of  claim 1 , further comprising a radiation source configured to provide the radiation to an object plane, wherein a wavelength of the radiation is about 30 nm or less. 
     
     
         22 . (canceled) 
     
     
         23 . (canceled) 
     
     
         24 . A tool, comprising:
 an illumination system comprising one or more optical elements; and   a catoptric microlithography projection optical system, comprising:
 a plurality of reflective elements configured to image radiation from an object field in an object plane of the catoptric microlithography projection optical system to an image field in an image plane of the catoptric microlithography projection optical system, 
   wherein:
 the catoptric microlithography projection optical system has an optical axis that is a common axis of rotational symmetry for each reflective element in the projection objective system;
     d=h (1− M ); 
 
 h is a distance of a central point of the object field from the optical axis in a direction perpendicular to the optical axis; 
 M is a magnification ratio of the optical system; 
 d is about 75 mm or less; 
 the image field has a size of at least 1 mm×1 mm; 
 the catoptric microlithography projection optical system has an image-side numerical aperture of about 0.2 or more; and 
 the tool is a microlithography tool. 
   
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . A method, comprising using the microlithography tool of  claim 24  to produce micro structured components.