Polarization-modulating element, illumination optical apparatus, exposure apparatus, and exposure method

• US 20090316132A1
• Filed: 08/25/2009
• Published: 12/24/2009
• Est. Priority Date: 02/06/2004
• Status: Abandoned Application

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Hirota, Hiroyuki, Tanitsu, Osamu, Shigematsu, Koji, Matsuyama, Tomoyuki
• Application Number:
  US12/461,801
• Publication Number:
  US 20090316132A1
• Time in Patent Office: Days
• US Class Current: 355/71
• CPC Class Codes: F21V 13/02 Combinations of only two kinds of elements
• CPC Class Codes: F21V 9/14 for producing polarised light
• CPC Class Codes: G02B 27/0977 Reflective elements
• 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 5/3025 Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state G02B5/3008, G02B5/3016 take precedence
• CPC Class Codes: G03F 7/701 Off-axis setting using an aperture
• 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 7/70308 Optical correction elements, filters or phase plates for manipulating imaging light, e.g. intensity, wavelength, polarisation, phase or image shift
• CPC Class Codes: G03F 7/70566 Polarisation control

Abstract

There is disclosed a polarization-modulating element for modulating a polarization state of incident light into a predetermined polarization state, the polarization-modulating element being made of an optical material with optical activity and having a circumferentially varying thickness profile.

Claims

1. An illumination optical apparatus for illuminating a surface to be illuminated, based on illumination radiation supplied form a radiation source, comprising:

a polarization modulating element, which is arranged in an optical path of the illumination radiation, which is made of an optical material with optical activity, and which has a circumferentially varying thickness; and

a movable optical element arranged in an optical path between the polarization modulating element and the surface to be illuminated.

2. The illumination optical apparatus according to claim 1, further comprising a zoom optical system, wherein the movable optical element is a part of the zoom optical system.

3. The illumination optical apparatus according to claim 1, further comprising an axicon system, wherein movable optical element is a part of the axicon system.

4. The illumination optical apparatus according to claim 1, wherein the polarization modulating element having sector shape elements.

5. The illumination optical apparatus according to claim 1, wherein the polarization modulating element having a central region with no substantial optical activity.

6. The illumination optical apparatus according to claim 5, wherein a radial size of the central region is not less than 3/10 of a radial size of an effective region of the polarization-modulating element.

7. The illumination optical apparatus according to claim 6, wherein a radial size of the central region is not less than ⅓

of a radial size of an effective region of the polarization-modulating element.

8. The illumination optical apparatus according to claim 5, further comprising a depolarizer arranged in an optical path in the central region.

9. The illumination optical apparatus according to claim 5, wherein the polarization modulating element having sector shape elements.

10. The illumination optical apparatus according to claim 1, further comprising an annular ratio changing optical system, wherein the movable optical element is a part of the annular ratio changing optical system, and wherein the annular ratio changing optical system that changes an annular ratio of a secondary radiation source formed on a pupil of the illumination optical apparatus.

11. The illumination optical apparatus according to claim 10, wherein the polarization-modulating element is disposed in an optical path between the radiation source and the annular ratio changing optical system, the illumination optical apparatus satisfying the following conditions:

(10in+Δ

A)/10out<

0.75;

0.4<

(10in+Δ

A)/10out,

where 10in;

an effective radius of a central region of the polarization-modulating element,

10out;

an outside effective radius of the polarization-modulating element, and

Δ

A;

an increase of an inside radius of a beam passing through the annular ratio changing optical system.

12. The illumination optical apparatus according to claim 1, further comprising an illumination sigma-value changing optical system, the movable optical element is a part of the illumination sigma-value changing optical system.

13. The illumination optical apparatus according to claim 1, wherein the thickness profile is so set that radiation in a linearly polarized state with a direction of polarization substantially along a single direction, is transformed into light in a azimuthal polarization state with a direction of polarization substantially along a circumferential direction or into radiation in a radially polarized state with a direction of polarization substantially along a radial direction.

14. The illumination optical apparatus according to claim 1, wherein the polarization modulating element having a plurality of circumferentially separated regions, wherein thicknesses of two arbitrary regions adjacent to each other among the plurality of regions are different from each other.

15. The illumination optical apparatus according to claim 14, wherein two arbitrary regions opposite to each other among the plurality of regions have their respective thicknesses substantially equal to each other.

16. The illumination optical apparatus according to claim 1, further comprising a polarization state controller arranged in an optical path between the radiation source and the polarization modulating element.

17. The illumination optical apparatus according to claim 16, wherein the polarization state controller having a rotating wave plate.

18. The illumination optical apparatus according to claim 1, wherein the optical material of the polarization modulating element is made of a crystal material whose crystallographic axis is set along a traveling direction of the incident light.

19. The illumination optical apparatus according to claim 1, wherein the polarization modulating element is selectively positioned in an optical path of the illumination radiation or out of the optical path of the illumination radiation.

20. The illumination optical apparatus according to claim 19, wherein the polarization modulating element is changeable to another polarization modulating element.

21. The illumination optical apparatus according to claim 1, wherein the illumination radiation on the surface to be illuminated having an average specific polarization rate over 70%.

22. The illumination optical apparatus according to claim 21, further comprising a polarization monitor which detects the illumination radiation.

23. The illumination optical apparatus according to claim 1, further comprising a beam transforming element arranged in an optical path between the radiation source and the polarization modulating element.

24. The illumination optical apparatus according to claim 23, wherein the polarization modulating element having a central region with no substantial optical activity.

25. The illumination optical apparatus according to claim 24, wherein the beam transforming element guides a radiation from the radiation source into an effective area of the polarization modulating element.

26. The illumination optical apparatus according to claim 24, wherein the beam transforming element guides a radiation from the radiation source into a central region of the polarization modulating element.

27. The illumination optical apparatus according to claim 23, wherein the polarization modulating element having radial extending boundary lines.

28. The illumination optical apparatus according to claim 27, wherein the beam transforming element guides a radiation from the radiation source into a region, which excludes the boundary line, of the polarization modulating element.

29. The illumination optical apparatus according to claim 1, further comprising a polarization monitor which detects the illumination radiation.

30. The illumination optical apparatus according to claim 29, further comprising a projection optical system, the polarization monitor is arranged incident side of the projection optical system.

31. The illumination optical apparatus according to claim 29, further comprising a projection optical system, the polarization monitor is arranged exit side of the projection optical system.

33. A device manufacturing method comprising the steps of:

projecting a predetermined pattern onto a photosensitive substrate, using the illumination optical apparatus according to claim 1, and developing the photosensitive substrate.

32. An exposure apparatus comprising the illumination optical apparatus according to clam 1,

wherein a predetermined pattern is projected onto a photosensitive substrate through the illumination optical apparatus.

34. An illumination optical apparatus for illuminating a surface to be illuminated, based on illumination radiation supplied form a radiation source, comprising:

a polarization modulating element, which is arranged in an optical path of the illumination radiation, which is made of an optical material with optical activity, and which has a circumferentially varying thickness; and

an optical integrator arranged in an optical path between the polarization modulating element and the surface to be illuminated,

wherein the polarization modulating element having a plurality of circumferentially separated regions, wherein thicknesses of two arbitrary regions adjacent to each other among the plurality of regions are different from each other.

36. A device manufacturing method comprising the steps of:

projecting a predetermined pattern onto a photosensitive substrate, using the illumination optical apparatus according to claim 34, and

developing the photosensitive substrate.

35. An exposure apparatus comprising the illumination optical apparatus according to clam 34,

wherein a predetermined pattern is projected onto a photosensitive substrate through the illumination optical apparatus.

37. An illumination optical apparatus for illuminating a surface to be illuminated, based on illumination radiation supplied form a radiation source, comprising:

a polarization modulating element, which is arranged in an optical path of the illumination radiation, which is made of an optical material with optical activity, and which has a circumferentially varying thickness; and

an annular ratio changing optical system, arranged in an optical path between the polarization modulating element and the surface to be illuminated, that changes an annular ratio of a secondary radiation source formed on a pupil of the illumination optical apparatus,

wherein the illumination optical apparatus satisfying the following conditions;

(10in+Δ

A)/10out<

0.75;

0.4<

(10in+Δ

A)/10out,

where 10in;

an effective radius of a central region of the polarization-modulating element,

10out;

an outside effective radius of the polarization-modulating element, and

Δ

A;

an increase of an inside radius of a beam passing through the annular ratio changing optical system.

38. The illumination optical apparatus according to claim 37, wherein the annular ratio changing optical system comprising an axicon system.

39. The illumination optical apparatus according to claim 38, further comprising an illumination sigma-value changing optical system.

41. A device manufacturing method comprising the steps of:

projecting a predetermined pattern onto a photosensitive substrate, using the illumination optical apparatus according to claim 37, and

developing the photosensitive substrate.

40. An exposure apparatus comprising the illumination optical apparatus according to clam 37,

wherein a predetermined pattern is projected onto a photosensitive substrate through the illumination optical apparatus.

42. A polarization-modulating element for modulating a polarization state of incident light into a predetermined polarization state, comprising:

a circumferentially varying thickness profile, and a central region with no substantial optical activity,

wherein the polarization-modulating element being made of an optical material with optical activity, and

wherein a radial size of the central region is not less than 3/10 of a radial size of an effective region of the polarization-modulating element.

43. The polarization-modulating element according to claim 42, wherein a radial size of the central region is not less than ⅓

of a radial size of an effective region of the polarization-modulating element.

44. The polarization-modulating element according to claim 42, further comprising a depolarizer arranged in an optical path in the central region.

45. The polarization-modulating element according to claim 42, wherein the polarization modulating element having sector shape elements.

46. An illumination optical system for illuminating a surface to be illuminated, based on illumination radiation supplied form a radiation source, comprising:

a polarization modulating element according to claim 42 arranged in an optical path of the illumination radiation.

47. The illumination optical system according to claim 46, further comprising an annular ratio changing optical system, arranged in an optical path between the polarization modulating element and the surface to be illuminated, that changes an annular ratio of a secondary radiation source formed on a pupil of the illumination optical apparatus.

48. The illumination optical system according to claim 47, wherein the illumination optical apparatus satisfying the following conditions:

(10in+Δ

A)/10out<

0.75;

0.4<

(10in+Δ

A)/10out,

where 10in;

an effective radius of a central region of the polarization-modulating element,

10out;

an outside effective radius of the polarization-modulating element, and

Δ

A;

an increase of an inside radius of a beam passing through the annular ratio changing optical system.

50. A device manufacturing method comprising the steps of:

projecting a predetermined pattern onto a photosensitive substrate, using the illumination optical apparatus according to claim 46, and

developing the photosensitive substrate.

49. An exposure apparatus comprising the illumination optical apparatus according to clam 46,

wherein a predetermined pattern is projected onto a photosensitive substrate through the illumination optical apparatus.

51. A polarization-modulating element for modulating a polarization state of incident light into a predetermined polarization state, and for using with an illumination optical apparatus having an annular ratio changing optical system, comprising:

a circumferentially varying thickness profile, and a central region with no substantial optical activity,

wherein the polarization-modulating element being made of an optical material with optical activity,

wherein the annular ratio changing optical system, arranged in an optical path between the polarization modulating element and a surface to be illuminated, that changes an annular ratio of a secondary radiation source formed on a pupil of the illumination optical apparatus, and

wherein the illumination optical apparatus satisfying the following conditions;

(10in+Δ

A)/10out<

0.75;

0.4<

(10in+Δ

A)/10out,

where 10in;

an effective radius of the central region of the polarization-modulating element,

10out;

an outside effective radius of the polarization-modulating element, and

Δ

A;

an increase of an inside radius of a beam passing through the annular ratio changing optical system.

52. The polarization-modulating element according to claim 51, wherein a radial size of the central region is not less than 3/10 of a radial size of an effective region of the polarization-modulating element.

53. The polarization-modulating element according to claim 52, wherein a radial size of the central region is not less than ⅓

of a radial size of an effective region of the polarization-modulating element.

54. The polarization-modulating element according to claim 51, further comprising a depolarizer arranged in an optical path in the central region.

55. The polarization-modulating element according to claim 51, wherein the polarization modulating element having sector shape elements.

56. A polarization monitor for detecting a beam in an optical path of an illumination optical apparatus which illuminates a surface to be illuminated base on a radiation from an radiation source, comprising:

an optical element arranged in an optical path of the beam; and

a detector which detect the beam through the optical element,

wherein the beam which enters the optical element passes through a polarization-modulating element and an optical integrator,

wherein the polarization-modulating element being made of an optical material with optical activity, and having a circumferentially varying thickness profile, and

wherein the optical integrator arranged in an optical path between the polarization-modulating element and the surface to be illuminated.

57. The polarization monitor according to claim 56, wherein the polarization monitor detects a beam which travels toward a projection optical system.

58. The polarization monitor according to claim 56, wherein the polarization monitor detects a beam via a projection optical system.

59. An exposure apparatus for projecting a predetermined pattern onto a photosensitive substrate, comprising:

an illumination optical apparatus which illuminates the predetermined pattern, and

the polarization monitor according to claim 56.

60. A device manufacturing method comprising the steps of:

projecting a predetermined pattern onto a photosensitive substrate, using the illumination optical apparatus,

detecting a radiation which is used under the projecting step, and

developing the photosensitive substrate.

61. A polarization monitoring method comprising the steps of:

receiving a radiation from a radiation source through a polarization-modulating element and an optical integrator,

detecting the radiation, and

analyzing a detecting result,

wherein the polarization-modulating element being made of an optical material with optical activity, and having a circumferentially varying thickness profile, and

wherein the optical integrator arranged in an optical path between the polarization-modulating element and a surface to be illuminated.

62. The polarization monitoring method according to claim 61, wherein detecting a beam which travels toward a projection optical system, in the detecting step.

63. The polarization monitoring method according to claim 61, wherein detecting a beam via a projection optical system, in the detecting step.

64. A method of adjusting an optical apparatus comprising:

supplying a radiation to the optical apparatus;

detecting a radiation through the optical apparatus using the method according to claim 61; and

adjusting the optical apparatus based on an analyzing result.

65. The adjusting method according to claim 64, wherein the adjusting step adjusts the polarization-modulating element.

66. An exposure apparatus for projecting a predetermined pattern onto a photosensitive substrate, comprising:

an illumination optical apparatus having the optical apparatus adjusted by the method according to claim 64, and

a substrate holder which hold the photosensitive substrate.

67. A device manufacturing method comprising the steps of:

projecting a predetermined pattern onto a photosensitive substrate, using the optical apparatus adjusted by the method according to claim 64, and

developing the photosensitive substrate.

68. A polarization monitor for detecting a beam in an optical path of an exposure apparatus which projects a predetermined pattern onto a photosensitive substrate positioned on a main surface, comprising:

an optical element arranged near the main surface; and

a detector which detect the beam through the optical element,

wherein the beam which enters the optical element passes through a polarization-modulating element and an optical integrator,

wherein the polarization-modulating element being made of an optical material with optical activity, and having a circumferentially varying thickness profile, and

wherein the optical integrator arranged in an optical path between the polarization-modulating element and the surface to be illuminated.

69. An exposure apparatus for projecting a predetermined pattern onto a photosensitive substrate, comprising:

the polarization monitor according to claim 68, and

a substrate holder which hold the photosensitive substrate.

70. A device manufacturing method comprising the steps of:

projecting a predetermined pattern onto a photosensitive substrate, using the exposure apparatus according to claim 69, and

developing the photosensitive substrate.

71. A method of producing a polarization-modulating element for modulating a polarization state of incident light into a predetermined polarization state, comprising:

a step of preparing an optical material with optical activity; and

a step of providing the optical material with a circumferentially varying thickness profile.

72. The production method of the polarization-modulating element according to claim 71, wherein the thickness profile is so set that light in a linearly polarized state with a direction of polarization substantially along a single direction, is transformed into light in a azimuthal polarization state with a direction of polarization substantially along a circumferential direction or into light in a radially polarized state with a direction of polarization substantially along a radial direction.

73. The production method of the polarization-modulating element according to claim 72, wherein the step of providing the circumferentially varying thickness profile is to provide such a thickness profile that thicknesses of two arbitrary regions adjacent to each other among a plurality of circumferentially separated regions are different from each other.

74. The production method of the polarization-modulating element according to claim 72, wherein two arbitrary regions opposite to each other among the plurality of regions have their respective angles of optical rotation substantially equal to each other.

75. The production method of the polarization-modulating element according to claim 74, wherein said two arbitrary regions opposite to each other have their respective thicknesses substantially equal to each other.

76. The production method of the polarization-modulating element according to claim 71, wherein the step of providing the circumferentially varying thickness profile is to provide a thickness profile circumferentially varying in a substantially continuous manner.

77. The production method of the polarization-modulating element according to claim 71, wherein the step of preparing the optical material with optical activity is to set the optical material so that a crystallographic axis thereof coincides with a traveling direction of the incident light.