Catadioptric projection systems

Abstract

Catadioptric projection systems are disclosed for projecting an illuminated region of a reticle onto a corresponding region on a substrate. The systems are preferably used with ultraviolet light sources (e.g., 193 nm). The systems comprise a first imaging system, a concave mirror, and a second imaging system. The first imaging system comprises a single-pass lens group and a double-pass lens group. The single-pass lens group comprises a first negative subgroup, a positive subgroup, and a second negative subgroup. Light from the illuminated region of the reticle passes through the single-pass lens group and the double-pass lens group, and reflects from the concave mirror to pass back through the double-pass lens group to form an intermediate image of the illuminated region of the reticle. The light is then directed to the second imaging system that re-images the illuminated region of the reticle on the substrate. Alternatively, light from the single-pass lens group is reflected by a turning mirror to the double-pass lens group, wherein the light returning through the double-pass lens group continues directly to the second imaging system.

1. A catadioptric projection system for receiving light from a reticle and projecting a pattern from the reticle onto a substrate, the catadioptric projection system comprising:
 a first imaging system that forms an intermediate image of an illuminated region of the reticle, the first imaging system comprising in order from the reticle and along an optical axis of the first imaging system, (a) a single-pass lens group comprising a first negative subgroup, a positive subgroup, and a second negative subgroup, and (b) a double-pass lens group comprising a concave mirror, wherein light from the illuminated region of the reticle passes through the single-pass lens group and the double-pass lens group, reflects from the concave mirror, and returns through the double-pass optical group;  
 a first turning mirror placed near the intermediate image that receives the light reflected by the concave mirror to and returned through the double-pass optical group; and  
 a second imaging system that receives the light reflected by the first turning mirror and that re-images the intermediate image to form a final image of the illuminated region of the reticle on the substrate.  
 
     
     
       2. The catadioptric projection system of  claim 1 , wherein the first negative subgroup of the single-pass lens group comprises a lens element with a concave surface facing the reticle. 
     
     
       3. The catadioptric projection system of  claim 1 , wherein the second negative subgroup of the single-pass lens group comprises a lens element with a concave surface facing the double-pass lens group. 
     
     
       4. The catadioptric projection system of  claim 2 , wherein the second negative subgroup of the single-pass lens group comprises a lens clement element with a concave surface facing the double-pass lens group. 
     
     
       5. The catadioptric projection system of  claim 1 , wherein either the first imaging system or the second imaging system produces a magnification of less than one. 
     
     
       6. The catadioptric projection system of  claim 1 , wherein the second imaging system comprises a first lens group and a second lens group, the system further comprising a second turning mirror placed between the first lens group and the second lens group and that receives light from the first lens group and directs the light to the second lens group. 
     
     
       7. The catadioptric projection system of  claim 1 , further comprising a third turning mirror placed between the single-pass lens group and the double-pass lens group and that receives light from the single-pass lens group and directs the light to the double-pass lens group. 
     
     
       8. The catadioptric projection system of  claim 7 , wherein the third turning mirror and the first turning mirror are arranged so that the light incident to the single-pass optical group and exiting the second lens group of the second imaging system propagate along substantially parallel axes. 
     
     
       9. The catadioptric projection system of  claim 8 , wherein the first axis and the second axis are colinear. 
     
     
       10. A catadioptric projection system for receiving light so from a reticle and projecting a pattern from the reticle onto a substrate, the catadioptric projection system comprising:
 a first imaging system that forms an intermediate image of an illuminated region of the reticle, the first imaging system comprising from objectwise to imagewisc imagewise, (a) a single-pass lens group comprising a first negative subgroup, a positive subgroup, and a second negative subgroup, and (b) a double-pass lens group comprising a concave mirror, wherein light from the illuminated region of the reticle passes through the single-pass lens group and the double-pass lens group, reflects from the concave mirror, and returns through the double-pass lens group;  
 a first turning mirror placed near the intermediate image, the first turning mirror separating the light propagating from the double-pass lens group from the light propagating to the double-pass lens group; and  
 a second imaging system that receives the light reflected by the concave mirror and reflected back through the double-pass lens group and that re-images the intermediate image to form a final image of the illuminated region of the reticle on the substrate.  
 
     
     
       11. The catadioptric projection system of  claim 10 , wherein the first negative subgroup of the single-pass lens group comprises a lens element with a concave surface facing the reticle. 
     
     
       12. The catadioptric projection system of  claim 10 , wherein the second negative subgroup of the single-pass lens group comprises a lens element with a concave surface facing the first turning mirror. 
     
     
       13. The catadioptric projection system of  claim 11 , wherein the second negative subgroup of the single-pass lens group comprises a lens element with a concave surface facing the first turning mirror. 
     
     
       14. The catadioptric projection system of  claim 10 , wherein either the first imaging system or the second imaging system produces a magnification of less than one. 
     
     
       15. The catadioptric projection system of  claim 10 , wherein the second imaging system comprises a first lens group and a second lens group, the system further comprising a second turning mirror placed between the first lens group and the second lens group and that receives light from the first lens group and directs the light to the second lens group. 
     
     
       16. The catadioptric projection system of  claim 14 , wherein the first turning mirror and the second turning mirror are arranged so that light entering the single-pass lens group propagates along a first axis and light reflected by the second turning mirror propagates along a second axis substantially parallel to the first axis. 
     
     
       17. In a method for projecting a pattern on a reticle onto a substrate in which a first imaging system receives light from the reticle and transmits the light through a single-pass lens group of the first imaging system and a double-pass lens group of the first imaging system, the double-pass lens group comprising a concave mirror, and reflecting the light from the concave mirror and returning the light through the double-pass optical group, and separating the light propagating from the double-pass lens group and the light propagating to the double-pass lens group, and directing the light propagating from the double-pass lens group to a second imaging system, an improvement comprising:
 (a) providing within the single-pass lens group, from objectwise to imagewise, a first negative subgroup, a positive subgroup, and a second negative subgroup;  
 (b) forming an intermediate image with the first imaging system between the first imaging system and the second imaging system; and  
 (c) locating the intermediate image in proximity to a turning mirror that separates the light propagating from the double-pass lens group from the light propagating to the double-pass lens group.  
 
     
     
       18. A method for projecting a pattern from a reticle onto a substrate, comprising the steps of:
 (a) providing a first imaging system comprising a single-pass lens group including from objectwise to imagewise, a first negative lens subgroup, a positive lens subgroup, and a second negative lens subgroup; and a double-pass lens group comprising a concave mirror;  
 (b) transmitting light from the reticle through the single-pass lens group and the double-pass lens group to the concave mirror, and returning the light reflected from the concave mirror back through the double-pass lens group toward the single-pass lens group;  
 (c) separating the light propagating through the double-pass lens group to the concave mirror from the light propagating through the double-pass lens group from the concave mirror;  
 (d) with the first imaging system, forming an intermediate image of the pattern between the first imaging system and the second imaging system;  
 (e) directing the light propagating from the concave mirror through the second imaging system; and  
 (f) forming an image of the reticle on the substrate with the second imaging system.  
 
     
     
       19. The method of  claim 18 , further comprising directing light from the single-pass lens group to the double-pass lens group using a first turning mirror. 
     
     
       20. The method of  claim 19 , further comprising directing the light, reflected by the concave mirror and returning through the double-pass lens group, to the second imaging system using a second turning mirror. 
     
     
       21. The method of  claim 20 , further comprising orienting the first turning mirror and the second turning mirror so that the light incident to the first turning mirror and the light reflected by the second turning mirror propagate along substantially parallel axes. 
     
     
       22. The method of  claim 21 , further comprising orienting the first turning mirror and the second turning mirror so that the light incident to the first turning mirror and the light reflected by the second turning mirror propagate along substantially the same axis. 
     
     
       23. The method of  claim 18 , further comprising:
 providing a first turning mirror placed between the single-pass lens group and the double-pass lens group; and  
 directing light, returning through the double-pass lens group from the concave mirror, to the second imaging system using the first turning mirror.  
 
     
     
       24. The method of  claim 23 , further comprising:
 providing the second imaging system with a first lens group and a second lens group;  
 providing a second turning mirror between the first lens group and the second lens group; and  
 directing light from the first lens group to the second lens group using the second turning mirror.  
 
     
     
       25. The method of  claim 24 , further comprising:
 arranging the first turning mirror and the second turning mirror so that the light incident to the first turning mirror and the light reflected by the second turning mirror propagate along substantially parallel axes.  
 
     
     
       26. An exposure system for projecting patterns on a reticle onto a substrate, the system comprising:
 (a) a catadioptric projection system that receives an illumination flux from an illuminated region on the reticle and forms an image of the illuminated region on the reticle on a corresponding region on the substrate;  
 (b) the catadioptric projection system comprising a first imaging system and a second imaging system, the first imaging system forming an intermediate image of the illuminated region of the reticle, and the second imaging system serving to re-image the intermediate image to form an image of the illuminated region of the reticle on the corresponding region of the substrate;  
 (c) the first imaging system comprising from objectwise to imagewise, (i) a single-pass lens group comprising a first negative subgroup, a positive subgroup, and a second negative subgroup; and (ii) a double-pass lens group comprising a concave mirror, wherein light from the illuminated region of the reticle passes through the single-pass lens group and the double-pass lens group, reflects from the concave mirror, and returns through the double-pass lens group;  
 (d) a first turning mirror situated near the intermediate image, the first turning mirror separating the light propagating from the double-pass lens group from the light propagating to the double-pass lens group; and  
 (e) a reticle scanner and a substrate scanner for respectively scanning the reticle and substrate synchronously to allow the caladioptric catadioptric projection system to project the patterns on the reticle onto the substrate.  
 
     
     
       27. A catadioptric imaging optical system in a projection exposure apparatus that transfers a pattern on a reticle which is arranged in a first plane onto a substrate which is arranged in a second plane, the system comprising:
   a catadioptric imaging optical sub - system comprising an optical group to form an image of the pattern, the optical group comprising a concave mirror with a first optical axis; and        a dioptric imaging sub - system arranged in an optical path between the catadioptric imaging optical sub - system and the second plane to re - image the image formed by the catadioptric imaging optical sub - system, the dioptric imaging sub - system comprising a second optical axis,        wherein      the first optical axis and the second optical axis are not parallel to each other,        the first plane and the second plane are arranged to be parallel to each other,        the optical group of said catadioptric imaging optical sub - system comprises a first optical subgroup comprising a third optical axis, and a second optical subgroup comprising the concave mirror and the first optical axis, and        the second and third axes form a straight optical axis.        
     
     
       28. A catadioptric imaging optical system according to  claim 27 , wherein the third optical axis and the second optical axis are parallel to each other. 
     
     
       29. A catadioptric imaging optical system according to  claim 27 , wherein the second optical subgroup comprises a negative lens and a positive lens. 
     
     
       30. A catadioptric imaging optical system according to  claim 27 , wherein said dioptric imaging optical sub- system further comprises an aperture stop.   
     
     
       31. A projection exposure apparatus that transfers a pattern on a reticle onto a substrate, comprising:
   an illumination optical system to illuminate the pattern on the reticle; and        a catadioptric imaging optical system according to    claim 30    to image the pattern onto the substrate,        wherein a σ can be varied, σ being a ratio of a numerical aperture of said catadioptric imaging optical system to a numerical aperture of said illumination optical system.     
     
     
       32. A catadioptric imaging optical system according to  claim 27 , wherein the image formed by said catadioptric imaging optical sub- system is a primary image of the pattern on the reticle.   
     
     
       33. A catadioptric imaging optical system according to  claim 27 , further comprising a first turning mirror arranged in an optical path between the concave mirror and said dioptric imaging optical sub- system.   
     
     
       34. A catadioptric imaging optical system according to  claim 33 , further comprising a second turning mirror arranged in an optical path between the concave mirror and the first plane. 
     
     
       35. A catadioptric imaging optical system according to  claim 34 , wherein the third optical axis and the second optical axis intersect. 
     
     
       36. A projection exposure apparatus that transfers a pattern on a reticle onto a substrate, comprising:
   a catadioptric imaging optical system according to    claim 27   , said catadioptric imaging optical system forms an exposure region on the substrate that is off of the second optical axis.     
     
     
       37. A projection exposure apparatus according to  claim 36 , wherein the reticle and the substrate are scanned at different speeds corresponding to the magnification of said catadioptric imaging optical system. 
     
     
       38. A method of imaging a pattern on a reticle which is arranged in a first plane onto a substrate which is arranged in a second plane, comprising:
   forming an intermediate image of the pattern on the reticle using a catadioptric imaging optical sub - system, wherein the catadioptric imaging optical sub - system comprises an optical group comprising a concave mirror with a first optical axis; and        re - imaging the intermediate image formed by the catadioptric imaging optical sub - system onto the substrate using a dioptric imaging sub - system arranged in an optical path between the catadioptric imaging optical sub - system and the second plane, wherein the dioptric imaging sub - system comprises a second optical axis,        wherein      the first optical axis and the second optical axis intersect,        the first plane and the second plane are arranged to be parallel to each other,        the optical group of said catadioptric imaging optical sub - system comprises a first optical subgroup comprising a third optical axis, and a second optical subgroup comprising the concave mirror and the first optical axis, and        the second and third optical axes form a straight optical axis.       
     
     
       39. A catadioptric imaging optical system used in a projection exposure apparatus that transfers a pattern on a reticle which is arranged in a first plane onto a substrate which is arranged in a second plane, comprising:
   a catadioptric imaging optical sub - system in an optical path between the first plane and the second plane, the catadioptric imaging optical sub - system comprising      a first optical group with a lens with a first optical axis, and        a second optical group with a concave mirror with a second optical axis; and          a dioptric imaging sub - system with a third optical axis arranged in an optical path between said catadioptric imaging optical sub - system and said substrate,        wherein      the first optical axis and second optical axis intersect,        the second optical axis and the third optical axis intersect, and        the first and third optical axes form a straight optical axis.       
     
     
       40. A projection exposure apparatus that transfers a pattern on a reticle onto a substrate, comprising:
   a catadioptric imaging optical sub - system according to    claim 39   ,        wherein said catadioptric imaging optical system forms the pattern on the reticle that is off of the first optical axis onto an exposure region on the substrate that is off of the third optical axis.     
     
     
       41. A projection exposure apparatus according to  claim 40 , wherein the reticle and the substrate are scanned at different speeds corresponding to the magnification of said catadioptric imaging optical sub- system.   
     
     
       42. A catadioptric imaging optical system according to  claim 39 , wherein the first and third optical axes are parallel to each other. 
     
     
       43. A method of imaging a pattern on a reticle onto a substrate, comprising:
   passing a light from the reticle through a first optical group comprising a lens with a first optical axis;        forming an intermediate image by a light passing through the first optical group and a second optical group, the second optical group comprising a concave mirror with a second optical axis; and        guiding a light having passes through the second optical group to the substrate by passing the light through a dioptric imaging optical sub - system with a third optical axis,        wherein      the first optical axis and the second optical axis intersect,        the second optical axis and the third optical axis intersect, and        the first and third optical axes form a straight optical axis.       
     
     
       44. A method according to  claim 43 , wherein in said forming comprises forming a primary image of the reticle. 
     
     
       45. A method according to  claim 43 , wherein the first and third optical axes are parallel to each other. 
     
     
       46. A catadioptric imaging optical system used in a projection exposure apparatus that transfers a pattern on a reticle which is arranged in a first plane onto a substrate which is arranged in a second plane, comprising:
   a first turning mirror arranged in an optical path between the first plane and the second plane;        a concave mirror arranged in an optical path between the first turning mirror and the second plane;        a second turning mirror arranged in an optical path between the concave mirror and the second plane; and        a dioptric imaging optical sub - system arranged in an optical path between the second turning mirror and the second plane and comprising an optical axis,        wherein      the first plane and the second plane are arranged to be parallel to each other, and        a first reflection surface of the first turning mirror and a second reflection surface of the second turning mirror are arranged to be non - parallel with each other.       
     
     
       47. A projection exposure apparatus that transfers a pattern on a reticle onto a substrate, comprising a catadioptric imaging optical system according to  claim 46 , wherein said catadioptric imaging optical system forms the pattern on the reticle off of the optical axis onto an exposure region on the substrate off of the optical axis. 
     
     
       48. A projection exposure apparatus according to  claim 47 , wherein the reticle and the substrate are scanned at different speeds corresponding to the magnification of said catadioptric imaging optical system. 
     
     
       49. A catadioptric imaging optical system according to  46 , wherein the optical axis of said dioptric imaging optical sub- system forms a straight line.   
     
     
       50. A method of imaging a pattern on a reticle which is arranged in a first plane onto a substrate which is arranged in a second plane, comprising:
   reflecting a light from the reticle with a first reflection surface of a first turning mirror;        reflecting the light from the first turning mirror with a concave mirror;        reflecting the light from the concave mirror using a second reflection surface of a second turning mirror;        passing the light from the second turning mirror to the substrate through a dioptric imaging optical sub - system having an optical axis;        forming an intermediate image of the pattern in an optical path between the concave mirror and the dioptric imaging optical sub - system; and        forming an image of the intermediate image on the substrate by the dioptric imaging optical sub - system,        wherein      the first plane and the second plane are arranged in parallel to each other, and        the first and second reflection surfaces are arranged to be non - parallel with each other.       
     
     
       51. A method according to  claim 50 , wherein said intermediate image is a primary image of the reticle. 
     
     
       52. A method according to  claim 50 , wherein the dioptric imaging optical sub- system comprises an optical axis along a straight line.   
     
     
       53. A catadioptric imaging optical system used in a projection exposure apparatus that transfers a pattern on a reticle which is arranged in a first plane onto a substrate which is arranged in a second plane, comprising:
   a catadioptric imaging optical sub - system in an optical path between the first plane and the second plane, the catadioptric imaging optical sub - system comprising      a first optical group with a lens with a first optical axis, and        a second optical group with a concave mirror with a second optical axis; and          a dioptric imaging sub - system with a third optical axis arranged in an optical path between the catadioptric imaging optical sub - system and the second plane,        wherein      the first optical axis and second optical axis intersect, and        the second optical axis and the third optical axis intersect        the first and third optical axes are parallel to each other, and        the first and third optical axes form a straight optical axis.       
     
     
       54. A method of imaging a pattern on a reticle onto a substrate, comprising:
   passing a light from the reticle through a first optical group comprising a lens with a first optical axis;        forming an intermediate image by a light passing through the first optical group and a second optical group, the second optical group comprising a concave mirror with a second optical axis; and        guiding a light having passes through the second optical group to the substrate by passing the light through a dioptric imaging optical sub - system with a third optical axis,        wherein      the first optical axis and the second optical axis intersect, and        the second optical axis and the third optical axis intersect,        the first and third optical axes are parallel to each other, and        the first and third optical axes form a straight optical axis.       
     
     
       55. A method for projecting a pattern from a reticle onto a substrate, comprising:
   transmitting light from the reticle through a first imaging system, where the transmitted light pass through a single - pass lens group and a double - pass lens group to a concave mirror, and the light is reflected from the concave mirror back through the double - pass lens group toward the single - pass lens group;        separating the light propagating through the double - pass lens group to the concave mirror from the light propagating through the double - pass lens group from the concave mirror;        with the first imaging system, forming an intermediate image of the pattern between the first imaging system and a second imaging system;        directing the light propagating from the concave mirror through the second imaging system; and        forming an image of the reticle on the substrate with the second imaging system, wherein      the single - pass lens group includes from objectwise to imagewise, a first negative lens subgroup, a positive lens subgroup, and a second negative lens subgroup, and        the double - pass lens group includes the concave mirror.       
     
     
       56. A catadioptric imaging optical system in a projection exposure apparatus that transfers a pattern on a reticle which is arranged in a first plane onto a substrate which is arranged in a second plane, the system comprising:
   a catadioptric imaging optical sub - system comprising an optical group to form an image of the pattern, the optical group comprising a concave mirror with a first optical axis; and        a dioptric imaging sub - system arranged in an optical path between the catadioptric imaging optical sub - system and the second plane to re - image the image formed by the catadioptric imaging optical sub - system, the dioptric imaging sub - system comprising a second optical axis,        wherein      the first optical axis and the second optical axis are not parallel to each other,        the first plane and the second plane are arranged to be parallel to each other, and        the dioptric imaging optical sub - system further comprises an aperture stop.       
     
     
       57. A catadioptric imaging optical system in a projection exposure apparatus that transfers a pattern on a reticle which is arranged in a first plane onto a substrate which is arranged in a second plane, the system comprising:
   a catadioptric imaging optical sub - system comprising an optical group to form an image of the pattern, the optical group comprising a concave mirror with a first optical axis; and        a dioptric imaging sub - system arranged in an optical path between the catadioptric imaging optical sub - system and the second plane to re - image the image formed by the catadioptric imaging optical sub - system, the dioptric imaging sub - system comprising a second optical axis;        wherein      the first optical axis and the second optical axis are not parallel to each other,        the first plane and the second plane are arranged to be parallel to each other,        the optical group of said catadioptric imaging optical sub - system comprises:      a first subgroup comprising a third optical axis, and        a second subgroup comprising the concave mirror and the first optical axis, and          the third optical axis and the second optical axis intersect.       
     
     
       58. A method of imaging a pattern on a reticle which is arranged in a first plane onto a substrate which is arranged in a second plane, comprising:
   forming an intermediate image of the pattern on the reticle using a catadioptric imaging optical sub - system, the catadioptric imaging optical sub - system comprising an optical group comprising a concave mirror and a first optical axis; and        re - imaging the intermediate image formed by the catadioptric imaging optical sub - system onto the substrate using a dioptric imaging sub - system arranged in an optical path between the catadioptric imaging optical sub - system and the second plane, the dioptric imaging sub - system comprising a second optical axis,        wherein      the first optical axis and the second optical axis intersect,        the first plane and the second plane are arranged to be parallel with each other, and        the dioptric imaging sub - system comprises an aperture stop.       
     
     
       59. A method of imaging a pattern on a reticle which is arranged in a first plane onto a substrate which is arranged in a second plane, comprising:
   forming an intermediate image of the pattern of the reticle using a catadioptric imaging optical sub - system, the catadioptric imaging optical sub - system comprising an optical group comprising a concave mirror and a first optical axis; and        re - imaging the intermediate image formed by the catadioptric imaging optical sub - system onto the substrate using a dioptric imaging sub - system arranged in an optical path between the catadioptric imaging optical sub - system and the second plane, the dioptric imaging sub - system comprising a second optical axis,        wherein      the first optical axis and the second optical axis intersect,        the first plane and the second plane are arranged to be parallel with each other, and        the optical group of the catadioptric imaging optical sub - system comprises a first subgroup comprising a third optical axis, and a second subgroup comprising the concave mirror and the first optical axis, and        the third optical axis and the second optical axis intersect.       
     
     
       60. A catadioptric imaging optical system in a projection exposure apparatus that transfers a pattern on a reticle which is arranged in a first plane onto a substrate which is arranged in a second plane, the system comprising:
   a catadioptric imaging optical sub - system comprising an optical group to form an image of the pattern, the optical group comprising a concave mirror with a first optical axis;        a dioptric imaging sub - system arranged in an optical path between the catadioptric imaging optical sub - system and the second plane to re - image the image formed by the catadioptric imaging optical sub - system, the dioptric imaging sub - system comprising a second optical axis;        a first turning mirror arranged in an optical path between the concave mirror and the dioptric imaging optical sub - system; and        a second turning mirror arranged in an optical path between the concave mirror and the first plane,        wherein      the first optical axis and the second optical axis are not parallel to each other,        the reticle and the substrate are arranged to be parallel to each other,        the optical group of said catadioptric imaging optical sub - system comprises:      a first subgroup comprising a third optical axis, and        a second subgroup comprising the concave mirror and the first optical axis; and          the third optical axis and the second optical axis intersect.