Illumination optical apparatus and projection exposure apparatus

• US 9,423,698 B2
• Filed: 05/15/2015
• Issued: 08/23/2016
• Est. Priority Date: 10/28/2003
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Shiraishi, Naomasa
• Primary Examiner(s): RIDDLE, CHRISTINA A
• Application Number:
  US14/713,428
• Publication Number:
  US 20150248066A1
• Time in Patent Office: 466 Days
• Field of Search: 355/52, 355/53, 355/55, 355 67- 71, 355/77, 250/492.1, 250/492.2, 250/492.22, 250/548, 362/19, 430/5, 430/8, 430/22, 430/30, 430/311, 430/312, 359/483.01, 359/489.15, 359/490.01, 359/492.01, 359/494
• US Class Current: 1/1
• 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 illuminates an object with illumination light. The apparatus includes a birefringent member having different thicknesses of a birefringent material at different incidence positions such that illumination light incident on the birefringent member in a first linear polarization state having a single polarization direction is in a second linear polarization state on a pupil plane, the second linear polarization state having a polarization direction being substantially coincident with a circumferential direction about an optical axis of the illumination optical apparatus.

Claims

1. An illumination optical apparatus which illuminates an object with illumination light, the apparatus comprising:

a light deflecting member arranged in an optical path of the illumination light, which deflects the illumination light;

a lens element arranged in the optical path of the illumination light from the light deflecting member;

a birefringent member including a birefringent material arranged in the optical path of the illumination light from the lens element to change a polarization state of the illumination light; and

an optical integrator arranged in the optical path between the birefringent member and a pupil plane of the illumination optical apparatus, wherein

the light deflecting member sets an incidence angle of the illumination light to the object on the basis of a deflection angle of the illumination light provided with the light deflecting member, the deflection angle being adjustable, and

the birefringent member includes different thicknesses of the birefringent material at different incidence positions such that the illumination light incident on the birefringent member in a first linear polarization state having a single polarization direction is in a second linear polarization state on the pupil plane, the second linear polarization state having a polarization direction being substantially coincident with a circumferential direction about an optical axis of the illumination optical apparatus.

2. The illumination optical apparatus according to claim 1, wherein the light deflecting member sets an incidence direction of the illumination light relative to the object to a plurality of substantially discrete directions on the basis of a deflection direction of the illumination light provided with the light deflecting member, the deflection direction being adjustable.

3. The illumination optical apparatus according to claim 1, wherein the birefringent member has a first thickness of the birefringent material at a first incidence position and a second thickness of the birefringent material at a second incidence position, the first incidence position being different from the second incidence position with respect to the circumferential direction, the first thicknesses being different from the second thickness.

4. The illumination optical apparatus according to claim 3, wherein a thickness configuration of the birefringent material continuously varies between the first thickness and the second thickness with respect to the circumferential direction.

5. The illumination optical apparatus according to claim 3, wherein a thickness configuration of the birefringent material uniformly varies between the first thickness and the second thickness with respect to the circumferential direction.

6. The illumination optical apparatus according to claim 3, wherein the first and second thicknesses are set such that a first part of the illumination light incident on the first incidence position has a first polarization direction on the pupil plane and a second part of the illumination light incident on the second incidence position has a second polarization direction on the pupil plane, the first and second polarization directions being different from each other.

7. The illumination optical apparatus according to claim 6, wherein the first polarization direction is perpendicular to the second polarization direction.

8. The illumination optical apparatus according to claim 1, further comprising a rotating mechanism which rotates the birefringent member about the optical axis.

9. The illumination optical apparatus according to claim 1, wherein the optical integrator is a fly'"'"'s eye lens.

10. The illumination optical apparatus according to claim 1, wherein an exit surface of the optical integrator is arranged at a position equivalent to the pupil plane.

11. The illumination optical apparatus according to claim 1, wherein an exit surface of the optical integrator is arranged so as to be coincident with an optical Fourier transform plane with respect to a plane on which the object is placed.

12. The illumination optical apparatus according to claim 1, wherein the illumination light is incident on the object in a polarization state consisting primarily of S-polarization.

13. An exposure apparatus which exposes a substrate to light passing through a pattern, the exposure apparatus comprising:

a stage which holds the substrate,

the illumination optical apparatus according to claim 1 which illuminates the pattern with the light; and

a projection optical system which projects an image of the pattern illuminated with the light from the illumination optical apparatus onto the substrate held by the stage.

14. The exposure apparatus according to claim 13, wherein the exposure apparatus is a liquid immersion exposure apparatus.

15. A device manufacturing method, comprising:

transferring a pattern to a substrate by use of the exposure apparatus according to claim 13; and

developing the substrate to which the pattern has been transferred.

16. The exposure apparatus according to claim 13, wherein the light deflecting member sets an incidence direction of the illumination light relative to the object to a plurality of substantially discrete directions on the basis of a deflection direction of the illumination light provided with the light deflecting member, the deflection direction being adjustable.

17. The exposure apparatus according to claim 13, wherein the birefringent member has a first thickness of the birefringent material at a first incidence position and a second thickness of the birefringent material at a second incidence position, the first incidence position being different from the second incidence position with respect to the circumferential direction, the first thicknesses being different from the second thickness.

18. The exposure apparatus according to claim 17, wherein a thickness configuration of the birefringent material continuously varies between the first thickness and the second thickness with respect to the circumferential direction.

19. The exposure apparatus according to claim 17, wherein a thickness configuration of the birefringent material uniformly varies between the first thickness and the second thickness with respect to the circumferential direction.

20. The exposure apparatus according to claim 17, wherein the first and second thicknesses are set such that a first part of the illumination light incident on the first incidence position has a first polarization direction on the pupil plane and a second part of the illumination light incident on the second incidence position has a second polarization direction on the pupil plane, the first and second polarization directions being different from each other.

21. The exposure apparatus according to claim 20, wherein the first polarization direction is perpendicular to the second polarization direction.

22. The exposure apparatus according to claim 13, further comprising a rotating mechanism which rotates the birefringent member about the optical axis.

23. The exposure apparatus according to claim 13, wherein the optical integrator is a fly'"'"'s eye lens.

24. The exposure apparatus according to claim 13, wherein an exit surface of the optical integrator is arranged at a position equivalent to the pupil plane.

25. The exposure apparatus according to claim 13, wherein an exit surface of the optical integrator is arranged so as to be coincident with an optical Fourier transform plane with respect to a plane on which the object is placed.

26. The exposure apparatus according to claim 13, wherein the illumination light is incident on the object in a polarization state consisting primarily of S-polarization.

27. An exposure method which exposes a substrate to light passing through a pattern, the exposure method comprising:

holding the substrate by a stage;

illuminating the pattern with the light by use of the illumination optical apparatus according to claim 1; and

projecting an image of the pattern illuminated with the light onto the substrate held by the stage.

28. The exposure method according to claim 27, wherein the substrate is exposed with the light through liquid.

29. A device manufacturing method, comprising:

transferring a pattern to a substrate by use of the exposure method according to claim 27; and

developing the substrate to which the pattern has been transferred.