ILLUMINATION OPTICAL DEVICE, OPTICAL UNIT, ILLUMINATION METHOD, AND EXPOSURE METHOD AND DEVICE

• US 20140293254A1
• Filed: 03/12/2014
• Published: 10/02/2014
• Est. Priority Date: 09/16/2011
• Status: Abandoned Application

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: KOMATSUDA, Hideki
• Application Number:
  US14/205,649
• Publication Number:
  US 20140293254A1
• Time in Patent Office: Days
• US Class Current: 355/67
• CPC Class Codes: G02B 26/06 for controlling the phase of light G02B26/08 takes precedence , measuring optical phase difference G01J9/00
• CPC Class Codes: G02B 27/0927 Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• CPC Class Codes: G03F 7/70058 Mask illumination systems
• 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 7/70566 Polarisation control

Abstract

An illumination device for illuminating a reticle surface as an illumination target surface with illumination light supplied from a light source is provided with a first polarization beam splitter for separating the illumination light into a first beam and a second beam with respective polarization directions orthogonal to each other; a deformable mirror which is arranged in an optical path of the second beam and a shape of a reflecting surface of which is variable for changing a phase difference distribution between the first beam and the second beam; and a second polarization beam splitter for combining the first beam and the second beam between which the phase difference distribution has been established. The illumination target surface can be illuminated with light having a distribution of various polarization states.

Claims

1. An illumination optical apparatus for illuminating an illumination target surface with light supplied from a light source, the illumination optical apparatus comprising:

a separating optical system which separates the light supplied from the light source, into a first beam and a second beam in respective polarization states different from each other;

a varying optical system which is arranged in an optical path of at least one of the first beam and the second beam and which varies a phase difference distribution between the first beam and the second beam; and

a combining optical system which combines the first beam and the second beam between which the phase difference distribution has been varied.

2. The illumination optical apparatus according to claim 1, comprising:

a polarization state changing element which is arranged in an optical path of a compound beam obtained by the combining optical system and which changes a polarization state of the compound beam.

4. The illumination optical apparatus according to claim 1,

wherein the varying optical system comprises a first partial optical system which the first beam passes, and a second partial optical system which the second beam passes, and

wherein the combining optical system is disposed at a position of an intersection where an optical axis on the combining optical system side of the first partial optical system intersects with an optical axis on the combining optical system side of the second partial optical system.

5. The illumination optical apparatus according to claim 4,

wherein the combining optical system comprises a combining face for combining the first beam and the second beam, and

wherein the combining face is disposed at the position of the intersection.

6. The illumination optical apparatus according to claim 1, wherein the varying optical system varies a phase difference distribution of one of the first beam and the second beam.

7. The illumination optical apparatus according to claim 2,

wherein the polarization state changing element changes the first beam and the second beam into circular polarization states in respective directions opposite to each other, and

wherein polarization states in a beam section of the first beam and the second beam after combined have linear polarizations directed in respective directions different from each other.

8. The illumination optical apparatus according to claim 7, wherein the polarization state changing element is a quarter wave plate.

9. The illumination optical apparatus according to claim 1, wherein the varying optical system includes a reflecting member which is arranged in an optical path of the first beam or the second beam and a shape of a reflecting surface of which is partially deformable.

10. The illumination optical apparatus according to claim 1, wherein at least one of the separating optical system and the combining optical system is a polarization beam splitter.

11. The illumination optical apparatus according to claim 1, wherein the separating optical system includes a half mirror for dividing the light supplied from the light source, and an optical element which is arranged in an optical path of one beam resulting from the dividing by the half mirror and which rotates a polarization direction of the beam.

12. The illumination optical apparatus according to claim 1, wherein the first beam and the second beam are linearly polarized light beams with respective polarization directions orthogonal to each other.

13. The illumination optical apparatus according to claim 1, comprising a wave plate which is arranged in an optical path of the light entering the separating optical system and which adjusts a polarization direction of the light.

14. The illumination optical apparatus according to claim 1, comprising:

a light quantity distribution forming optical system which is arranged in an optical path of the light entering the separating optical system and which forms a light quantity distribution of light at a predetermined position in an illumination optical path of the illumination optical apparatus; and

a surface illuminant forming optical system which is arranged in an optical path of a compound beam obtained by the combining optical system and which effects wavefront division of the compound beam to form a surface illuminant with a light quantity distribution equivalent to the light quantity distribution of the light.

15. The illumination optical apparatus according to claim 14, wherein the varying optical system is disposed in the vicinity of an exit pupil of the illumination optical apparatus or a face equivalent to a face conjugate with the exit pupil.

16. The illumination optical apparatus according to claim 15, wherein the varying optical system includes a reflecting member which is disposed in an optical path of the first beam or the second beam and in the vicinity of the exit pupil of the illumination optical apparatus or the face equivalent to the face conjugate with the exit pupil, and a shape of a reflecting surface of which is partially deformable.

17. An exposure apparatus for illuminating a pattern with exposure light and exposing a substrate with the exposure light via the pattern and a projection optical system, the exposure apparatus comprising:

the illumination optical apparatus as set forth in claim 1,

wherein light from the illumination optical apparatus is used as the exposure light.

3. An illumination optical apparatus for illuminating an illumination target surface with light supplied from a light source, the illumination optical apparatus comprising:

a separating optical system which separates the light supplied from the light source, into a first beam and a second beam in respective polarization states different from each other;

a varying optical system which is arranged in an optical path of at least one of the first beam and the second beam and which varies a phase difference distribution between the first beam and the second beam;

a combining optical system which combines the first beam and the second beam the phase difference distribution between which has been varied; and

a polarization state changing element which is arranged in an optical path of a compound beam obtained by the combining optical system and which changes a polarization state of the compound beam.

25. The illumination optical apparatus according to claim 3,

wherein the varying optical system comprises a first partial optical system which the first beam passes, and a second partial optical system which the second beam passes, and

wherein the combining optical system is disposed at a position of an intersection where an optical axis on the combining optical system side of the first partial optical system intersects with an optical axis on the combining optical system side of the second partial optical system.

26. The illumination optical apparatus according to claim 25,

wherein the combining optical system comprises a combining face for combining the first beam and the second beam, and

wherein the combining face is disposed at the position of the intersection.

27. The illumination optical apparatus according to claim 3, wherein the varying optical system varies a phase difference distribution of one of the first beam and the second beam.

28. The illumination optical apparatus according to claim 3,

wherein the polarization state changing element changes the first beam and the second beam into circular polarization states in respective directions opposite to each other, and

wherein polarization states in a beam section of the first beam and the second beam after combined have linear polarizations directed in respective directions different from each other.

29. The illumination optical apparatus according to claim 28, wherein the polarization state changing element is a quarter wave plate.

30. The illumination optical apparatus according to claim 3, wherein the varying optical system includes a reflecting member which is arranged in an optical path of the first beam or the second beam and a shape of a reflecting surface of which is partially deformable.

31. The illumination optical apparatus according to claim 3, wherein at least one of the separating optical system and the combining optical system is a polarization beam splitter.

32. The illumination optical apparatus according to claim 3, wherein the separating optical system includes a half mirror for dividing the light supplied from the light source, and an optical element which is arranged in an optical path of one beam resulting from the dividing by the half mirror and which rotates a polarization direction of the beam.

33. The illumination optical apparatus according to claim 3, wherein the first beam and the second beam are linearly polarized light beams with respective polarization directions orthogonal to each other.

34. The illumination optical apparatus according to claim 3, comprising a wave plate which is arranged in an optical path of the light entering the separating optical system and which adjusts a polarization direction of the light.

35. The illumination optical apparatus according to claim 3, comprising:

a light quantity distribution forming optical system which is arranged in an optical path of the light entering the separating optical system and which forms a light quantity distribution of light at a predetermined position in an illumination optical path of the illumination optical apparatus; and

a surface illuminant forming optical system which is arranged in an optical path of a compound beam obtained by the combining optical system and which effects wavefront division of the compound beam to form a surface illuminant with a light quantity distribution equivalent to the light quantity distribution of the light.

36. The illumination optical apparatus according to claim 35, wherein the varying optical system is disposed in the vicinity of an exit pupil of the illumination optical apparatus or a face equivalent to a face conjugate with the exit pupil.

37. The illumination optical apparatus according to claim 36, wherein the varying optical system includes a reflecting member which is disposed in an optical path of the first beam or the second beam and in the vicinity of the exit pupil of the illumination optical apparatus or the face equivalent to the face conjugate with the exit pupil, and a shape of a reflecting surface of which is partially deformable.

38. An exposure apparatus for illuminating a pattern with exposure light and exposing a substrate with the exposure light via the pattern and a projection optical system, the exposure apparatus comprising:

the illumination optical apparatus as set forth in claim 3,

wherein light from the illumination optical apparatus is used as the exposure light.

18. An optical unit for changing a polarization state of light supplied from a light source, the optical unit comprising:

a separating optical system which separates the light supplied from the light source, into a first beam and a second beam in respective polarization states different from each other;

a varying optical system which is arranged in an optical path of at least one of the first beam and the second beam and which varies a phase difference distribution between the first beam and the second beam;

a combining optical system which combines the first beam and the second beam between which the phase difference distribution has been varied; and

a polarization state changing element which is arranged in an optical path of a compound beam obtained by the combining optical system and which changes a polarization state of the compound beam.

19. The optical unit according to claim 18, wherein the varying optical system includes a reflecting member which is arranged in an optical path of the first beam or the second beam and a shape of a reflecting surface of which is partially deformable.

20. An illumination method for illuminating an illumination target surface with light supplied from a light source, the illumination method comprising:

separating the light supplied from the light source, into a first beam and a second beam in respective polarization states different from each other;

establishing a variable phase difference distribution between the first beam and the second beam; and

combining the first beam and the second beam the variable phase difference distribution between which has been established.

21. The illumination method according to claim 20, wherein the beams after combined are guided through a wave plate.

23. An exposure method for illuminating a pattern with exposure light and exposing a substrate with the exposure light via the pattern and a projection optical system, the exposure method comprising:

employing the illumination method as set forth in claim 20, to use the light directed toward the illumination target surface, as the exposure light.

24. A device manufacturing method comprising:

forming a pattern of a photosensitive layer on the substrate, using the exposure method as set forth in claim 23; and

processing the substrate with the pattern formed thereon.

22. An illumination method for illuminating an illumination target surface with light supplied from a light source, the illumination method comprising:

separating the light supplied from the light source, into a first beam and a second beam in respective polarization states different from each other;

varying a phase difference distribution between the first beam and the second beam;

combining the first beam and the second beam between which the phase difference distribution has been varied; and

guiding a compound beam obtained by a combining optical system, through a polarization state changing element.

39. An exposure method for illuminating a pattern with exposure light and exposing a substrate with the exposure light via the pattern and a projection optical system, the exposure method comprising:

employing the illumination method as set forth in claim 22, to use the light directed toward the illumination target surface, as the exposure light.

40. A device manufacturing method comprising:

forming a pattern of a photosensitive layer on the substrate, using the exposure method as set forth in claim 39; and

processing the substrate with the pattern formed thereon.