Illumination optical apparatus and projection exposure apparatus

• US 20060203214A1
• Filed: 04/26/2006
• Published: 09/14/2006
• Est. Priority Date: 10/28/2003
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Shiraishi, Naomasa
• Granted Patent: US 9,140,992 B2
• Time in Patent Office: Days
• US Class Current: 355/52
• CPC Class Codes: G02B 27/28 for polarising used in stereoscopes G02B30/25
• CPC Class Codes: G02B 27/286 for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G03F 7/70108 Off-axis setting using a light-guiding element, e.g. diffractive optical elements [DOEs] or light guides
• CPC Class Codes: G03F 7/70191 Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like
• CPC Class Codes: G03F 7/70341 Details of immersion lithography aspects, e.g. exposure media or control of immersion liquid supply chemical composition of immersion liquids G03F7/2041
• CPC Class Codes: G03F 7/70566 Polarisation control
• CPC Class Codes: G03F 7/70966 Birefringence

Abstract

An illumination optical apparatus and projection exposure apparatus capable of reducing a light quantity loss when a mask is illuminated with a polarized illumination light. An illumination optical system for illuminating a reticle with an illumination light and a projection optical system for projecting the pattern image of the reticle onto a wafer are provided. An illumination light emitted from an exposure light source in a linearly polarized state in the illumination optical system passes through first and second birefringent members having different fast axis directions and is converted into a polarized state that is substantially linearly polarized in a circumferential direction with the optical axis as the center in an almost specific annular area, and them illuminates the reticle under an annular illuminating condition after passing through a fly-eye lens.

Claims

1. A projection exposure apparatus for projecting a pattern image on a first object on a second object, the projection exposure apparatus comprising:

a projection optical system for projecting the image of pattern on the first object on the second object; and

an illumination optical system for illuminating a first object with illumination light from a light source, and comprising at least two birefringent members arranged along a traveling direction of the illumination light, wherein a direction of a fast axis of at least one birefringent member out of the birefringent members is different from a direction of a fast axis of the other birefringent member, and wherein a specific illumination beam incident in a specific incidence angle range to the first object among the illumination light generated in a substantially single polarization state from the light source is light in a polarization state consisting primarily of S-polarization.

2. The projection exposure apparatus according to claim 1, further comprising a beam limiting member for limiting the illumination light incident to the first object, to the specific illumination beam.

3. The projection exposure apparatus according to claim 2, wherein the beam limiting member further limits an incidence direction of the illumination light incident to the first object to a plurality of specific, substantially discrete directions.

4. The projection exposure apparatus according to claim 2 wherein the beam limiting member includes a diffractive optical element disposed between the light source and the birefringent members.

5. The projection exposure apparatus according to claim 1, wherein the at least one member out of the birefringent members is a nonuniform wavelength plate in which a polarization phase difference, which is a phase difference given between a linear polarization component parallel to the fast axis and a linear polarization component parallel to a slow axis in transmitted light, nonlinearly varies according to locations in the member.

6. The projection exposure apparatus according to claim 5, wherein the nonuniform wavelength plate includes a first nonuniform wavelength plate for giving the polarization phase difference with 2-fold rotation symmetry about the optical axis of the illumination optical system, to the specific illumination light or to the illumination light distributed in the specific annular region.

7. The projection exposure apparatus according to claim 6, wherein the nonuniform wavelength plate further includes a second nonuniform wavelength plate for giving the polarization phase difference with 1-fold rotation symmetry about the optical axis of the illumination optical system, to the specific illumination light or to the illumination light distributed in the specific annular region.

8. The projection exposure apparatus according to claim 7, wherein directions of the fast axes of the first and second nonuniform wavelength plates are shifted by 45°

from each other about a rotation center on the optical axis of the illumination optical system.

9. The projection exposure apparatus according to claim 1, further comprising an optical integrator disposed between the birefringent members and the first object.

10. The projection exposure apparatus according to claim 9, further comprising a zoom optical system, a conical prism group or a polyhedron prism group with a variable spacing disposed between the birefringent members and the optical integrator.

11. The projection exposure apparatus according to claim 10, wherein the optical integrator is a fly'"'"'s eye lens.

12. The projection exposure apparatus according to claim 1, further comprising a polarization controlling mechanism disposed between the light source and the birefringent members and arranged to convert the polarization state of the illumination light from the light source.

13. The projection exposure apparatus according to claim 1, further comprising a rotating mechanism for enabling rotation of some or all of the birefringent members about the optical axis of the illumination optical system.

14. The projection exposure apparatus according to claim 1, further comprising plural sets of said birefringent members, and a birefringent member replacing mechanism for replaceably placing the birefringent members in the plural sets, in the illumination optical system.

15. An exposure method of exposing a photosensitive body as the second object to an image of a pattern on a mask as the first object, using the projection exposure apparatus as defined in claim 1.

16. A device fabrication method comprising a lithography step,

wherein in the lithography step a pattern is transferred onto a photosensitive body by the exposure method defined in claim 15.

17. An exposure method of exposing a photosensitive body as the second object to an image of a pattern on a mask as the first object, using the projection exposure apparatus defined in claim 4.

18. A device fabrication method comprising a lithography step,

wherein in the lithography step a pattern is transferred onto a photosensitive body by the exposure method defined in claim 17.

19. A projection exposure apparatus for projecting an image of a pattern on a first object onto a second object, comprising:

a projection optical system for projecting the image of the pattern on the first object onto the second object; and

an illumination optical system for illuminating the first object with light supplied from an outside light source, the illumination optical system comprising a diffractive optical element and a birefringent member arranged in order along a traveling direction of the light.

20. The projection exposure apparatus according to claim 19, wherein the diffractive optical element substantially limits the light incident to the first object among the light in a substantially single polarization state supplied from the light source, to a specific illumination beam incident in a specific incidence angle range to the first object, and

wherein the birefringent member converts the specific illumination beam into light in a polarization state consisting primarily of S-polarization.

21. The projection exposure apparatus according to claim 20, wherein the diffractive optical element further limits an incidence direction of the illumination light incident to the first object, to a plurality of specific, substantially discrete directions.

22. The projection exposure apparatus according to claim 19, wherein the diffractive optical element substantially limits the illumination light to a beam distributed in a specific annular region being a predetermined annular region centered around an optical axis of the illumination optical system, in a pupil plane in the illumination optical system, and

wherein the birefringent member converts the beam into a polarization state consisting primarily of linear polarization with a polarization direction along a circumferential direction.

23. The projection exposure apparatus according to claim 22, wherein the diffractive optical element further limits the beam to within a plurality of substantially discrete regions in the specific annular region.

24. The projection exposure apparatus according to claim 19, wherein the birefringent member is a nonuniform wavelength plate in which a polarization phase difference, which is a phase difference given between a linear polarization component parallel to the fast axis and a linear polarization component parallel to a slow axis in transmitted light, nonlinearly varies according to locations in the member.

25. The projection exposure apparatus according to claim 19, wherein the birefringent member comprises crystalline quartz.

26. The projection exposure apparatus according to claim 20, wherein the birefringent member comprises crystalline quartz.

27. The projection exposure apparatus according to claim 19, wherein the birefringent member is arranged on a pupil plane or a plane conjugate with the pupil plane in the illumination optical system.

28. The projection exposure apparatus according to claim 20, wherein the birefringent member is arranged on a pupil plane or a plane conjugate with the pupil plane in the illumination optical system.

29. The projection exposure apparatus according to claim 19, wherein the birefringent member has nonuniform thicknesses in the traveling direction of the illumination light.

30. The projection exposure apparatus according to claim 19, further comprising an optical integrator disposed between the birefringent member and the first object.

31. The projection exposure apparatus according to claim 30, further comprising at least one of a zoom optical system, a conical prism group and a polyhedron prism group with a variable spacing, disposed between the birefringent member and the optical integrator.

32. The projection exposure apparatus according to claim 30, wherein the optical integrator is a fly'"'"'s eye lens.

33. The projection exposure apparatus according to claim 20, further comprising an optical integrator disposed between the birefringent member and the first object.

34. The projection exposure apparatus according to claim 33, further comprising at least one of a zoom optical system, a conical prism group with a variable spacing, and a polyhedron prism group with a variable spacing, disposed between the birefringent member and the optical integrator.

35. The projection exposure apparatus according to claim 33, wherein the optical integrator is a fly'"'"'s eye lens.

36. The projection exposure apparatus according to claim 19, further comprising a polarization controlling mechanism disposed between the light source and the birefringent member and arranged to convert the polarization state of the illumination light from the light source.

37. The projection exposure apparatus according to claim 20, further comprising a polarization controlling mechanism disposed between the light source and the birefringent member and arranged to convert the polarization state of the illumination light from the light source.

38. The projection exposure apparatus according to claim 19, further comprising a rotating mechanism for enabling rotation of the birefringent members about the optical axis of the illumination optical system.

39. The projection exposure apparatus according to claim 20, further comprising a rotating mechanism for enabling rotation of the birefringent member about the optical axis of the illumination optical system.

40. The projection exposure apparatus according to claim 19, further comprising plural sets of said birefringent members, and a birefringent member replacing mechanism for replaceably placing the birefringent members in the plural sets.

41. The projection exposure apparatus according to claim 20, further comprising plural sets of said birefringent members, and a birefringent member replacing mechanism for replaceably placing the birefringent members in the plural sets.

42. An exposure method of exposing a photosensitive body as the second object to an image of a pattern on a mask as the first object, using the projection exposure apparatus as defined in claim 19.

43. A device fabrication method comprising a lithography step,

wherein in the lithography step a pattern is transferred onto a photosensitive body by the exposure method defined in claim 42.

44. An exposure method of exposing a photosensitive body as the second object to an image of a pattern on a mask as the first object, using the projection exposure apparatus as defined in claim 20.

45. A device fabrication method comprising a lithography step,

wherein in the lithography step a pattern is transferred onto a photosensitive body by the exposure method defined in claim 44.

46. An illumination optical apparatus for illuminating a first object with illumination light from a light source, comprising:

at least two birefringent members arranged along a traveling direction of the illumination light,

wherein a direction of a fast axis of at least one birefringent member out of the birefringent members is different from a direction of a fast axis of the other birefringent member, and

wherein a specific illumination beam incident in a specific incidence angle range onto the first object among the light in a substantially single polarization state supplied from the light source is light in a polarization state consisting primarily of S-polarization.

47. The illumination optical apparatus according to claim 46, further comprising a beam limiting member for limiting the light incident to the first object, to the specific illumination beam.

48. The illumination optical apparatus according to claim 47, wherein the beam limiting member further limits an incidence direction of the illumination light incident to the first object to a plurality of specific, substantially discrete directions.

49. The illumination optical apparatus according to claim 47, wherein the beam limiting member includes a diffractive optical element.

50. The illumination optical apparatus according to claim 46, wherein the at least one member out of the birefringent members is a nonuniform wavelength plate in which a polarization phase difference, which is a phase difference given between a linear polarization component parallel to the fast axis and a linear polarization component parallel to a slow axis in transmitted light, nonlinearly varies according to locations in the member.

51. The illumination optical apparatus according to claim 50, wherein the nonuniform wavelength plate includes a first nonuniform wavelength plate for giving the polarization phase difference with 2-fold rotation symmetry about the optical axis of the illumination optical system, to the specific illumination light or to the illumination light distributed in the specific annular region.

52. The illumination optical apparatus according to claim 51, wherein the nonuniform wavelength plate further includes a second nonuniform wavelength plate for giving the polarization phase difference with 1-fold rotation symmetry about the optical axis of the illumination optical system, to the specific illumination light or to the illumination light distributed in the specific annular region.

53. The illumination optical apparatus according to claim 52, wherein directions of the fast axes of the first and second nonuniform wavelength plates are shifted by 45°

from each other about a rotation center on the optical axis of the illumination optical system.

54. The illumination optical apparatus according to claim 46, further comprising an optical integrator disposed between the birefringent members and the first object.

55. The illumination optical apparatus according to claim 47, wherein the beam limiting member is a diffractive optical element,

the illumination optical apparatus comprising an optical integrator disposed between the birefringent members and the first object.

56. An illumination optical apparatus for illuminating a first object with light supplied from an outside light source, comprising:

a diffractive optical element and a birefringent member arranged in order along a traveling direction of the light.

57. The illumination optical apparatus according to claim 56, wherein the diffractive optical element substantially limits the light incident to the first object among the light in a substantially single polarization state supplied from the outside light source, to a specific illumination beam incident in a specific incidence angle range to the first object, and

wherein the birefringent member converts the specific illumination beam into light in a polarization state consisting primarily of S-polarization.

58. The illumination optical apparatus according to claim 57, wherein the diffractive optical element further limits an incidence direction of the illumination light incident to the first object, to a plurality of specific, substantially discrete directions.

59. The illumination optical apparatus according to claim 56, wherein the birefringent member is a nonuniform wavelength plate in which a polarization phase difference, which is a phase difference given between a linear polarization component parallel to the fast axis and a linear polarization component parallel to a slow axis in transmitted light, nonlinearly varies according to locations in the member.

60. The illumination optical apparatus according to claim 56, wherein the birefringent member comprises crystalline quartz.

61. The illumination optical apparatus according to claim 57, wherein the birefringent member comprises crystalline quartz.

62. The illumination optical apparatus according to claim 56, wherein the birefringent member is arranged on a pupil plane or a plane conjugate with the pupil plane in the illumination optical system.

63. The illumination optical apparatus according to claim 57, wherein the birefringent member is arranged on a pupil plane or a plane conjugate with the pupil plane in the illumination optical system.

64. The illumination optical apparatus according to claim 56, wherein the birefringent member has nonuniform thicknesses in the traveling direction of the illumination light.

65. The illumination optical apparatus according to claim 56, further comprising an optical integrator disposed between the birefringent member and the first object.

66. The illumination optical apparatus according to claim 65, further comprising at least one of a zoom optical system, a conical prism group and a polyhedron prism group with a variable spacing, disposed between the birefringent member and the optical integrator.

67. The illumination optical apparatus according to claim 65, wherein the optical integrator is a fly'"'"'s eye lens.

68. The illumination optical apparatus according to claim 57, further comprising an optical integrator disposed between the birefringent member and the first object.

69. The illumination optical apparatus according to claim 68, further comprising at least one of a zoom optical system, a conical prism group with a variable spacing, and a polyhedron prism group with a variable spacing, disposed between the birefringent member and the optical integrator.

70. The illumination optical apparatus according to claim 68, wherein the optical integrator is a fly'"'"'s eye lens.

71. The illumination optical apparatus according to claim 56, comprising further a polarization controlling mechanism disposed between the light source and the birefringent member and arranged to convert the polarization state of the illumination light from the light source.

72. The illumination optical apparatus according to claim 57, comprising further a polarization controlling mechanism disposed between the light source and the birefringent member and arranged to convert the polarization state of the illumination light from the light source.

73. The illumination optical apparatus according to claim 56, further comprising a rotating mechanism for enabling rotation of the birefringent member about the optical axis of the illumination optical system.

74. The illumination optical apparatus according to claim 57, further comprising a rotating mechanism for enabling rotation of the birefringent member about the optical axis of the illumination optical system.

75. The illumination optical apparatus according to claim 56, further comprising plural sets of said birefringent members, and a birefringent member replacing mechanism for replaceably placing the birefringent members in the plural sets, in the illumination optical system.

76. The illumination optical apparatus according to claim 57, further comprising plural sets of said birefringent members, and a birefringent member replacing mechanism for replaceably placing the birefringent members in the plural sets, in the illumination optical system.