USRE38438EExpiredUtility

Catadioptric reduction projection optical system and exposure apparatus having the same

Assignee: NIPPON KOGAKU KKPriority: Aug 23, 1994Filed: Jan 19, 2001Granted: Feb 24, 2004

Est. expiryAug 23, 2014(expired)· nominal 20-yr term from priority

Inventors:Tomowaki Takahashi

G03F 7/70275G03F 7/70358G02B 17/08G02B 17/0892G03F 7/70225

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Claims

Abstract

A catadioptric projection optical system is provided, which can use a beam splitting optical system smaller in size than a conventional polarizing beam splitter, can set a long optical path from a concave reflecting mirror to an image plane, allows easy adjustment of the optical system, and has excellent imaging performance. A light beam from an object surface forms a first intermediate image through a refracting lens group. A light beam from the first intermediate image passes through a polarizing beam splitter and is reflected by a concave reflecting mirror to form a second intermediate image in the polarizing beam splitter. A light beam from the second intermediate image is reflected by the polarizing beam splitter means to form a final image on the image plane via a refracting lens group. The polarizing beam splitter means is arranged near the positions at which the intermediate images are formed.

Claims

exact text as granted — not AI-modified

What is claimed is:

1. A catadioptric reduction projection optical system for projecting a reduced image of a pattern of a first surface onto a second surface, comprising:
a first imaging optical system having a positive refractive power and for forming a first intermediate image as a reduced image of the pattern on the first surface;
beam splitting means for splitting at least part of a light beam from said first imaging optical system;
a second imaging optical system including a concave reflecting mirror for reflecting a light beam split by said beam splitting means, said second imaging optical system having a positive refractive power and for forming a second intermediate image as an image of the first intermediate image; and
a third imaging optical system for forming a third intermediate image as an image of the second intermediate image on the second surface on the basis of a light beam, of a light beam from said second imaging optical system, which is split by said beam splitting means.

2. A system according to claim 1 , wherein said beam splitting means is a prism type beam splitter, and at least one of the first intermediate image and the second intermediate image is formed in said prism type beam splitter.

3. A system according to claim 2 , wherein an optical axis of said first imaging optical system corresponds to an optical axis of said second imaging optical system, and said beam splitting means is disposed between said first imaging optical system and said second imaging optical system.

4. A system according to claim 2 , wherein an optical axis of said second imaging optical system corresponds to an optical axis of said third imaging optical system, and said beam splitting means is disposed between said second imaging optical system and said third imaging optical system.

5. A system according to claim 1 , wherein said beam splitting means is a partial reflecting mirror for partially reflecting a light beam, and the second intermediate image is formed between said beam splitting means and said concave reflecting mirror of said second imaging optical system.

6. A system according to claim 5 , wherein said partial reflecting mirror is disposed so as to avoid optical axes of said first and third imaging optical systems.

7. A system according to claim 1 , wherein the following conditions are satisfied:

p 1 +p 3 &gt;0, p 2 &lt;0,

and

|p 1 +p 2 +p 3 |&lt;0.1

where p 1 is the Petzval sum of said first imaging optical system, p 2 is the Petzval sum of said second imaging optical system, and p 3 is the Petzval sum of said third imaging optical system, and the following conditions are satisfied:

0.1≦|β 1 |≦1,

0.5≦|β 2 |≦2,

0.25≦|β 3 |≦1.5, and

|β 1 ·β 2 ·β 3 |&lt;1

where β 1 is the magnification between the pattern of the first surface and the first intermediate image, β 2 is the magnification between the first intermediate image and the second intermediate image, and β 3 is the magnification between the second intermediate image and the third intermediate image.

8. An exposure apparatus comprising:
a first stage allowing a photosensitive substrate to be held on a main surface thereof;
a second stage for supporting a mask on which a predetermined pattern is formed;
an illumination optical system for emitting exposure light of a predetermined wavelength and transferring the pattern of the mask onto the substrate; and
a catadioptric reduction projection optical system provided between said first stage and said second stage, for projecting a reduced image of the pattern of the mask onto the substrate, said catadioptric reduction projection optical system including:
a first imaging optical system having a positive refractive power and for forming a first intermediate image as a reduced image of the pattern on the mask;
beam splitting means for splitting at least part of a light beam from said first imaging optical system;
a second imaging optical system including a concave reflecting mirror for reflecting a light beam split by said beam splitting means, and for forming a second intermediate image as an image of the first intermediate image; and
a third imaging optical system for forming a third intermediate image as an image of the second intermediate image on the substrate on the basis of a light beam, of a light beam from said second imaging optical system, which is split by said beam splitting means.

9. An apparatus according to claim 8 , wherein said beam splitting means is a prism type beam splitter, and at least one of the first intermediate image and the second intermediate image is formed in said prism type beam splitter.

10. An apparatus according to claim 9 , wherein an optical axis of said first imaging optical system corresponds to an optical axis of said second imaging optical system, and said beam splitting means is disposed between said first imaging optical system and said second imaging optical system.

11. An apparatus according to claim 9 , wherein an optical axis of said second imaging optical system corresponds to an optical axis of said third imaging optical system, and said beam splitting means is disposed between said second imaging optical system and said third imaging optical system.

12. An apparatus according to claim 8 , wherein said beam splitting means is a partial reflecting mirror for partially reflecting a light beam, and the second intermediate image is formed between said beam splitting means and said concave reflecting mirror of said second imaging optical system.

13. An apparatus according to claim 12 , wherein said partial reflecting mirror is disposed so as to avoid optical axes of said first and third imaging optical systems.

14. An apparatus according to claim 8 , wherein the following conditions are satisfied:

p 1 +p 3 &gt;0, p 2 &lt;0,

and

|p 1 +p 2 +p 3 |&lt;0.1

0.1≦|β 1 |≦1,

0.5≦|β 2 |≦2,

0.25≦|β 3 |≦1.5, and

|β 1 ·β 2 ·β 3 |&lt;1

15. A catadioptric imaging optical system in a projection exposure apparatus in which a pattern on a reticle placed on a first surface is transmitted onto a substrate placed on a second surface, comprising:
a first dioptric imaging optical sub - system;
a catadioptric imaging optical sub - system in an optical path between said first dioptric imaging optical sub - system and the second surface, comprising a concave mirror and a catadioptric optical axis; and
a second dioptric imaging optical sub - system in an optical path between said catadioptric imaging optical sub - system and the second surface, comprising a second dioptric optical axis,

wherein

a primary image is formed between said first dioptric imaging optical sub - system and said catadioptric imaging optical sub - system,
a secondary image is formed between said catadioptric imaging optical sub - system and said second dioptric imaging optical sub - system, and

the catadioptric optical axis intersects the second dioptric optical axis.

16. The optical system according to claim 15 , wherein said catadioptric imaging optical sub- system further comprises a negative power lens.

17. The optical system according to claim 15 , further comprising a turning mirror located off the second dioptric optical axis.

18. The optical system according to claim 17 , wherein the secondary image is formed between said turning mirror and the concave mirror.

19. The optical system according to claim 15 , further comprising an aperture stop in said first and/or second dioptric optical sub- system, which controls a coherent factor.

20. The optical system according to claim 15 , wherein the second dioptric optical axis is along a straight line.

21. The optical system according to claim 20 , wherein said first dioptric imaging optical sub- system comprises a first dioptric optical axis along a straight line.

22. A projection exposure apparatus which transfers a pattern on a reticle onto a substrate, comprising:

a catadioptric imaging optical system according to
claim 15
, wherein said catadioptric imaging optical system forms an exposure area at a position off the second dioptric optical axis.

23. The projection exposure apparatus according to claim 22 , wherein the reticle and the substrate are scanned at different speeds corresponding to a magnification of said catadioptric imaging optical system.

24. A method of imaging a pattern on a reticle onto a substrate, comprising:
passing a light from the reticle through a first dioptric imaging optical sub - system;
passing a light from the first dioptric imaging optical sub - system through a catadioptric imaging optical subsystem having a concave mirror;
passing a light from the catadioptric optical sub - system through a second dioptric imaging optical sub - system;
forming a primary image between the first dioptric imaging optical sub - system and the catadioptric imaging optical system;
forming a secondary image between the catadioptric imaging optical system and the second dioptric imaging optical sub - system; and

turning an optical path near the primary image.

25. A method of imaging a pattern on a reticle onto a substrate, comprising:
passing a light from the reticle through a first dioptric imaging optical sub - system;
passing a light from the first dioptric imaging optical sub - system through a catadioptric imaging optical subsystem having a concave mirror;
passing a light from the catadioptric optical sub - system through a second dioptric imaging optical sub - system;
forming a primary image between the first dioptric imaging optical sub - system and the catadioptric imaging optical system;
forming a secondary image between the catadioptric imaging optical system and the second dioptric imaging optical sub - system; and

turning an optical path near the secondary image.

26. The method according to claim 25 , wherein the optical path is turned by a turning mirror located off an optical axis of the second dioptric imaging optical sub- system.

27. The method according to claim 25 , further comprising controlling a coherent factor using an aperture stop in the first and/or second dioptric imaging optical sub- system.

28. The method according to claim 27 , further comprising arranging the reticle and the substrate to be parallel.

29. The method according to claim 28 , further comprising turning an optical path in the first dioptric imaging optical sub- system.

30. A catadioptric imaging optical system in a projection exposure apparatus in which a pattern on a reticle placed on a first surface is transferred onto a substrate placed on a second surface, comprising:
a first dioptric imaging optical sub - system;
a catadioptric imaging optical sub - system in an optical path between said first dioptric imaging optical sub - system and the second surface, comprising a concave mirror;
a second dioptric imaging optical sub - system in an optical path between said catadioptric imaging optical sub - system and the second surface; and
a turning mirror between said catadioptric imaging optical system and said second dioptric imaging optical sub - system,

wherein

a primary image is formed between said first dioptric imaging optical sub - system and said catadioptric imaging sub - system, and
a secondary image is formed between said catadioptric imaging optical sub - system and said second dioptric imaging optical sub - system.

31. The optical system according to claim 30 , wherein the secondary image is formed between said turning mirror and the concave mirror.

32. The optical system according to claim 30 , further comprising an aperture stop in said first and/or second dioptric optical sub- system, which controls a coherent factor.

33. The optical system according to claim 30 , wherein said second dioptric imaging optical sub- system has an optical axis along a straight line.

34. The optical system according to claim 33 , wherein said first dioptric imaging optical sub- system has an optical axis along a straight line.

35. A projection exposure apparatus which transfers a pattern on a reticle onto a substrate, comprising:
a catadioptric imaging optical system according to claim 30 , wherein said catadioptric imaging optical system forms an exposure area off an optical axis of said second dioptric imaging optical sub - system.

36. The projection exposure apparatus according to claim 35 , wherein the reticle and the substrate are scanned at different speeds corresponding to a magnification of said catadioptric imaging optical system.

37. A method of imaging a pattern on a reticle onto a substrate, comprising:
forming a primary image of the reticle by a first dioptric imaging optical sub - system, based on light from the reticle;
forming a secondary image of the reticle using a catadioptric imaging optical sub - system having a concave mirror, based on light from the first dioptric imaging optical sub - system;
forming a final image of the reticle on the substrate using a second dioptric imaging optical sub - system, based on light from the catadioptric imaging optical system; and
turning an optical path between the catadioptric imaging optical system and the second dioptric imaging optical sub - system.

38. A catadioptric imaging optical system in a projection exposure apparatus in which a pattern on a reticle placed on a first surface is transferred onto a substrate placed on a second surface, comprising:
a first dioptric imaging optical sub - system comprising an optical axis along a straight line;
a catadioptric imaging optical sub - system in an optical path between said first dioptric imaging optical sub - system and the second surface, comprising a concave mirror and an optical axis along a straight line; and
a second dioptric imaging optical sub - system in an optical path between said catadioptric imaging optical sub - system and the second surface, comprising an optical axis along a straight line.

39. The optical system according to claim 15 , wherein said first dioptric imaging optical sub- system, said catadioptric imaging optical sub - system, and said second dioptric imaging optical sub - system further comprise lenses having the same material.

40. The optical system according to claim 15 , wherein the optical system satisfies the following conditions:

0.1≦|β 1 |≦ 1 ,

0.5≦|β 2 |≦ 2 ,

0.25≦|β 3 |≦ 1 . 5 , and

|β 1 ·β 2 ·β 3 |&lt; 1

where β 1 is the magnification for said first dioptric imaging optical sub - system, β 2 is a magnification for said catadioptric imaging optical sub - system, and β 3 is a magnification for said second dioptric imaging sub - system.

41. The optical system according to claim 15 , further comprising a turning mirror, and wherein the first surface is parallel to the second surface.

42. The optical system according to claim 41 , wherein said turning mirror is in said first dioptric imaging sub- system.

43. A method of imaging a pattern on a reticle onto a substrate, comprising:
forming a primary image of the pattern using a first dioptric imaging optical sub - system comprising a first dioptric optical axis along a straight line;
forming a secondary image of the pattern using a catadioptric imaging optical sub - system comprising a concave mirror and a catadioptric optical axis along a straight line, the second image being formed using light received from the first dioptric imaging optical sub - system; and
forming a final image of the pattern on the substrate using a second dioptric imaging optical sub - system comprising a second dioptric optical axis along a straight line, the final image being formed using light received from the catadioptric imaging optical sub - system.

44. A catadioptric optical system comprising:
a first refractive optical sub - system;
a refractive - reflective optical sub - system; and
a second refractive optical sub - system;
wherein said first refractive optical sub - system forms an intermediate image of an object, the intermediate image being in an optical path between said first refractive optical sub - system and said refractive - reflective optical sub - system, and
wherein said refractive - reflective optical sub - system forms an image of the intermediate image in an optical path between said refractive - reflective optical sub - system and said second refractive optical sub - system.

45. The catadioptric optical system according to claim 44 , wherein said second refractive optical sub- system forms a tertiary image of the object.

46. The catadioptric optical system according to claim 44 , wherein the catadioptric optical system forms a reduced image of the object.

47. The catadioptric optical system according to claim 44 , wherein said first refractive optical sub- system and said refractive - reflective optical sub - system have a common optical axis.

48. The catadioptric optical system according to claim 44 , further comprising a folding mirror disposed along an optical path between said refractive- reflective optical sub - system and one of said first and second refractive optical sub - systems.

49. The catadioptric optical system according to claim 48 , wherein said folding mirror is arranged in an optical path between said refractive- reflective optical sub - system and said second refractive optical sub - system.

50. The catadioptric optical system according to claim 49 , wherein said second refractive optical sub- system forms a tertiary image of the object.

51. The catadioptric optical system according to claim 44 , wherein said refractive- reflective optical sub - system comprises a concave reflective mirror and a negative lens through which light passes prior to and after reflection from the concave reflective mirror.

52. The catadioptric optical system according to claim 51 , wherein the negative lens comprises a concave lens surface, and wherein the concave lens surface and a concave reflective surface of the concave reflective mirror are concave in a same direction.

53. The catadioptric optical system according to claim 52 , wherein the negative lens has a meniscus shape.

54. The catadioptric optical system according to claim 44 , wherein a first light received from said first refractive- optical sub - system toward said refractive - reflective optical sub - system and a second light received from said refractive - reflective optical sub - system toward said second refractive optical sub - system are separated each other.

55. The catadioptric optical system according to claim 54 , wherein the first light and the second light pass through an off- axis region.

56. The catadioptric optical system according to claim 55 , further comprising a folding mirror disposed along an optical path between said refractive- reflective optical sub - system and one of said first and second refractive optical sub - systems.

57. The catadioptric optical system according to claim 56 , wherein said folding mirror is arranged in an optical path between said refractive- reflective optical sub - system and said second refractive optical sub - system.

58. An imaging method for imaging an image of an object, the method comprising:
forming an intermediate image of the object with a first refractive optical sub - system, the intermediate image being formed in an optical path between the first refractive optical sub - system and a refractive - reflective optical sub - system;
forming an image of the intermediate image with said refractive - reflective optical sub - system, the image of the intermediate image being formed in an optical path between the refractive - reflective optical sub - system and a second refractive optical sub - system,
wherein the first refractive optical sub - system and the refractive - reflective optical sub - system are imaging optical systems.

59. The imaging method according to claim 58 , further comprising forming a tertiary image of the object with the second refractive optical sub- system.

60. The imaging method according to claim 58 , wherein the first refractive optical sub- system, the second refractive optical sub - system, and the refractive - reflective optical sub - system comprise a catadioptric optical system that forms a reduced image of the object.

61. The imaging method according to claim 58 , wherein the first refractive optical sub- system and the refractive - reflective optical sub - system having a common optical axis.

62. The imaging method according to claim 58 , further comprising folding a light received from the refractive- reflective optical sub - system toward the second refractive optical sub - system.

63. The imaging method according to claim 62 , further comprising forming a tertiary image of the object using the second refractive optical sub- system.

64. The imaging method according to claim 58 , wherein a first light received from the first refractive- optical sub - system toward the refractive - reflective optical sub - system and a second light received from the refractive - reflective optical sub - system toward the second refractive optical sub - system are separated each other.

65. The method according to claim 64 , wherein the first light and the second light pass through an off- axis region.

66. The imaging method according to claim 65 , further comprising folding a light received from the refractive- reflective optical sub - system toward the second refractive optical sub - system.

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