Illumination device

• US 5,459,547 A
• Filed: 06/25/1993
• Issued: 10/17/1995
• Est. Priority Date: 06/25/1992
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Shiozawa, Takahisa
• Primary Examiner(s): WINTERCORN, RICHARD
• Application Number:
  US08/081,194
• Time in Patent Office: 844 Days
• Field of Search: 362/268, 355/53, 355/67, 355/70
• US Class Current: 355/67
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 3/0062 Stacked lens arrays, i.e. refractive surfaces arranged in at least two planes, without structurally separate optical elements in-between
• CPC Class Codes: G03F 7/70075 Homogenization of illumination intensity in the mask plane by using an integrator, e.g. fly's eye lens, facet mirror or glass rod, by using a diffusing optical element or by beam deflection
• CPC Class Codes: G03F 7/701 Off-axis setting using an aperture
• CPC Class Codes: G03F 7/70108 Off-axis setting using a light-guiding element, e.g. diffractive optical elements [DOEs] or light guides

Abstract

An illumination device includes first and second optical integrators disposed along an optical axis and each having lens elements arrayed in a direction intersecting the optical axis; a condensing optical system for collecting light passed through the first and second optical integrators, to form a secondary light source; and a mechanism for relatively shifting the second optical integrator relative to the first optical integrator, in a direction intersecting the optical axis.

Claims

1. An illumination device, comprising:

first and second optical integrators disposed along an optical axis and each having lens elements arrayed in a direction transverse to the optical axis;

an optical system for receiving light passed through said first and second optical integrators, and for forming a secondary light source; and

means for relatively shifting said second optical integrator relative to said first optical integrator, in a direction transverse to the optical axis.

2. A device according to claim 1, wherein said lens elements of said first and second optical integrators are arrayed at the same pitch, and wherein said shifting means shifts said second optical integrator selectively between a first state in which said lens elements of said first and second optical integrators are placed coaxially and a second state in which said lens elements of said first and second optical integrators are relatively deviated by a half of said pitch.

3. A device according to claim 1 or 2, wherein said optical system includes prism means demountably insertable into a path of the light.

4. A device according to claim 1 or 2, wherein said optical system includes a variable-magnification optical system.

5. A device according to claim 1 or 2, wherein each of said lens elements of each of said first and second optical integrators has a square sectional shape.

6. A device according to claim 1 or 2, wherein said shifting means includes means for relatively shifting said second optical integrator relative to said first optical integrator along the optical axis.

45. A device according to claim 1, wherein a light entrance surface of said first optical integrator is optically conjugate with a light exit surface of said second optical integrator.

7. An illumination device, comprising:

light source means;

first, second and third optical integrators disposed along an optical axis, for receiving light from said light source means, each of said first to third optical integrators having lens elements arrayed in a direction transverse to the optical axis;

a first optical system for directing, onto said third optical integrator, light passed through said first and second optical integrators, to form a secondary light source of said third optical integrator;

a second optical system for directing light from said secondary light source to a surface to be illuminated; and

means for relatively shifting said second optical integrator relative to said first optical integrator, in a direction transverse to the optical axis.

8. A device according to claim 7, wherein said lens elements of said first and second optical integrators are arrayed at the same pitch, and wherein said shifting means shifts said second optical integrator selectively between a first state in which said lens elements of said first and second optical integrators are placed coaxially and a second state in which said lens elements of said first and second optical integrators are relatively deviated by a half of said pitch.

9. A device according to claim 8, wherein said first optical system includes prism means demountably insertable into a path of the light.

10. A device according to claim 8, wherein said first optical system includes a variable-magnification optical system.

11. A device according to claim 8, wherein each of said lens elements of each of said first, and second optical integrators has a square sectional shape.

12. A device according to claim 8, wherein said shifting means includes means for relatively shifting said second optical integrator relative to said first optical integrator along the optical axis.

13. A device according to claim 8, wherein said light source means includes a light emitting portion, an elliptical mirror for collecting light from said light emitting portion, and an imaging lens system for directing light collectively reflected by said elliptical mirror to said first optical integrator, and wherein said imaging lens system serves to image said light emitting portion on said first optical integrator.

14. A device according to claim 8, wherein said light source means includes a light emitting portion, an elliptical mirror with an opening, for collecting light from said light emitting portion, and an imaging lens system for directing light collectively reflected by said elliptical mirror to said first optical integrator, and wherein said imaging lens system serves to image said opening of said elliptical mirror on said first optical integrator.

15. A device according to claim 8, further comprising a stop disposed adjacent to a light exit surface of said third optical integrator, for adjusting the shape of said secondary light source.

46. A device according to claim 7, wherein a light entrance surface of said first optical integrator is optically conjugate with a light exit surface of said second optical integrator, and wherein a light entrance surface of

16. An exposure apparatus for exposing a substrate to a mask, comprising:

first and second optical integrators disposed along an optical axis and each having lens elements arrayed in a direction transverse to the optical axis;

an optical system for receiving light passed through said first and second optical integrators, and for forming a secondary light source for illumination of the mask; and

means for relatively shifting said second optical integrator relative to said first optical integrator, in a direction transverse to the optical axis.

17. An apparatus according to claim 16, wherein said lens elements of said first and second optical integrators are arrayed at the same pitch, and wherein said shifting means shifts said second optical integrator selectively between a first state in which said lens elements of said first and second optical integrators are placed coaxially and a second state in which said lens elements of said first and second optical integrators are relatively deviated by a half of said pitch.

18. An apparatus according to claim 16 or 17, wherein said optical system includes prism means demountably insertable into a path of the light.

19. An apparatus according to claim 16 or 17, wherein said optical system includes a variable-magnification optical system.

20. An apparatus according to claim 16 or 17, wherein each of said lens elements of each of said first and second optical integrators has a square sectional shape.

21. An apparatus according to claim 16 or 17, wherein said shifting means includes means for relatively shifting said second optical integrator relative to said first optical integrator along the optical axis.

22. An illumination device, comprising:

first and second optical integrators disposed along an optical axis and each having lens elements arrayed in a direction transverse to the optical axis, said lens elements of said first and second optical integrators having a relative eccentricity in their optical axes; and

an optical system for receiving light passed through said first and second optical integrators, and for forming a secondary light source.

23. A device according to claim 22, wherein said lens elements of said first and second optical integrators are arrayed at the same pitch, and wherein said lens elements of said first and second optical integrators are relatively deviated by a half of said pitch.

24. A device according to claim 22, wherein said optical system includes prism means demountably insertable into a path of the light.

25. A device according to claim 22, wherein said optical system includes a variable-magnification optical system.

26. A device according to claim 22, wherein each of said lens elements of each of said first and second optical integrators has a square sectional shape.

47. A device according to claim 22, wherein a light entrance surface of said first optical integrator is optically conjugate with a light exit surface of said second optical integrator.

27. An illumination device, comprising:

light source means;

first, second and third optical integrators disposed along an optical axis, for receiving light from said light source means, each of said first to third optical integrators having lens elements arrayed in a direction transverse to the optical axis, said lens elements of said first and second optical integrators having relative eccentricity in their optical axes;

a first optical system for directing, onto said third optical integrator, light passed through said first and second optical integrators, to form a secondary light source through said third optical integrator; and

a second optical system for directing light from said secondary light source to a surface to be illuminated.

28. A device according to claim 27, wherein said lens elements of said first and second optical integrators are arrayed at the same pitch, and wherein the optical axes of said lens elements of said first, second and third optical integrators are relatively deviated by a half of said pitch.

29. A device according to claim 28, wherein said first optical system includes prism means demountably insertable into a path of the light.

30. A device according to claim 28, wherein said first optical system includes a variable-magnification optical system.

31. A device according to claim 28, wherein each of said lens elements of each of said first and second optical integrators has a square sectional shape.

32. A device according to claim 28, wherein said light source means includes a light emitting portion, an elliptical mirror for collecting light from said light emitting portion, and an imaging lens system for directing light collectively reflected by said elliptical mirror to said first optical integrator, and wherein said imaging lens system serves to image said light emitting portion on said first optical integrator.

33. A device according to claim 28, wherein said light source means includes a light emitting portion, an elliptical mirror with an opening, for collecting light from said light emitting portion, and an imaging lens system for directing light collectively reflected by said elliptical mirror to said first optical integrator, and wherein said imaging lens system serves to image said opening of said elliptical mirror on said first optical integrator.

34. A device according to claim 28, further comprising a stop disposed adjacent to a light exit surface of said third optical integrator, for adjusting the shape of said secondary light source.

48. A device according to claim 27, wherein a light entrance surface of said first optical integrator is optically conjugate with a light exit surface of said second optical integrator, and wherein a light entrance of said second optical integrator is optically conjugate with a light entrance surface of said third optical integrator.

35. An exposure apparatus for exposing a substrate to a mask, comprising:

first and second optical integrators disposed along an optical axis and each having lens elements arrayed in a direction transverse to the optical axis, said lens elements of said first and second optical integrators having a relative eccentricity in their optical axes; and

an optical system for receiving light passed through said first and second optical integrators, and for forming a secondary light source.

36. An apparatus according to claim 35, wherein said lens elements of said first and second optical integrators are arrayed at the same pitch, and wherein said lens elements of said first and second optical integrators are relatively deviated by a half of said pitch.

37. An apparatus according to claim 36, wherein said optical system includes prism means demountably insertable into a path of the light.

38. An apparatus according to claim 36, wherein said optical system includes a variable-magnification optical system.

39. An apparatus according to claim 36, wherein each of said lens elements of each of said first and second optical integrators has a square sectional shape.

49. An apparatus according to claim 35, wherein a light entrance surface of said first optical integrator is optically conjugate with a light exit surface of said second optical integrator.

40. An exposure apparatus for exposing a substrate to a mask, comprising:

light source means;

first, second and third optical integrators disposed along an optical axis, for receiving light from said light source means, each of said first to third optical integrators having lens elements arrayed in a direction transverse to the optical axis, said lens elements of said first and second optical integrators having relative eccentricity in their optical axes;

a first optical system for directing, onto said third optical integrator, light passed through said first and second optical integrators, to form a secondary light source through said third optical integrator;

a second optical system for directing light from said secondary light source to a surface to be illuminated; and

a projection optical system for projecting an image of a pattern of the mask, irradiated with said secondary light source, to the substrate.

41. An apparatus according to claim 40, wherein said lens elements of said first and second optical integrators are arrayed at the same pitch, and wherein the optical axes of said lens elements of said first, second and third optical integrators are relatively deviated by a half of said pitch.

42. An apparatus according to claim 40, wherein said condensing optical system includes prism means demountably insertable into a path of the light.

43. An apparatus according to claim 40, wherein said condensing optical system includes a variable-magnification optical system.

44. An apparatus according to claim 40, wherein each of said lens elements of each of said first and second optical integrators has a square sectional shape.

50. An apparatus according to claim 40, wherein a light entrance surface of said first optical integrator is optically conjugate with a light exit surface of said second optical integrator, and a light entrance surface of said second optical integrator is optically conjugate with a light entrance surface of said third optical integrator.