Illumination optical device, illumination method, and exposure method and device

• US 9,310,604 B2
• Filed: 06/12/2012
• Issued: 04/12/2016
• Est. Priority Date: 02/03/2010
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Fujii, Toru
• Primary Examiner(s): Persaud, Deoram
• Application Number:
  US13/494,749
• Publication Number:
  US 20120249989A1
• Time in Patent Office: 1,400 Days
• Field of Search: 355/71, 359/290, 359/291
• US Class Current: 1/1
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 27/0933 Systems for active beam shaping by rapid movement of an element
• 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 7/70116 Off-axis setting using a programmable means, e.g. liquid crystal display [LCD], digital micromirror device [DMD] or pupil facets
• 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 7/702 Reflective illumination, i.e. reflective optical elements other than folding mirrors, e.g. extreme ultraviolet [EUV] illumination systems
• CPC Class Codes: G03F 7/70208 Multiple illumination paths, e.g. radiation distribution devices, microlens illumination systems, multiplexers or demultiplexers for single or multiple projection systems
• CPC Class Codes: G03F 7/70566 Polarisation control

Abstract

An illumination optical apparatus includes a light splitting device which splits the beam into a plurality of beams with respective polarization states different from each other, a spatial light modulation device which is arranged on at least one of a first optical path in which a first beam out of the plurality of beams travels and a second optical path in which a second beam out of the plurality of beams travels, and which has a plurality of optical elements arranged two-dimensionally and driven individually and a control device which controls the spatial modulation device to combine the first beam and the second beam at least in part.

Claims

1. An illumination optical apparatus which illuminates an illumination target surface through use of a beam, comprising:

a light splitting device which splits the beam into a plurality of beams with respective polarization states different from each other;

a spatial light modulation device which is arranged on at least one of a first optical path in which a first beam out of the plurality of beams travels and a second optical path in which a second beam out of the plurality of beams travels, and which is configured to adjust a phase difference between the first beam and the second beam by changing an optical path length of the first optical path and an optical length of the second optical path; and

an optical system which illuminates the illumination target surface with light wherein the first beam and the second beam are overlapped at least in part,

wherein polarization states of the first beam and the second beam overlapped at least in part are adjusted by adjusting the phase difference between the first beam and the second beam.

2. The illumination optical apparatus according to claim 1, further comprising a controller which controls the spatial light modulation device.

3. The illumination optical apparatus according to claim 2, wherein the spatial light modulation device includes reflecting elements with inclination angles and heights controllable, and

wherein the controller controls the heights of the reflecting elements in the spatial modulation device.

4. The illumination optical apparatus according claim 2 , wherein the spatial light modulation device comprises:

a spatial light modulator with a plurality of optical elements arranged two-dimensionally and driven individually on the first optical path; and

a reflecting optical member arranged on the second optical path and having a reflecting surface, and

wherein the controller overlaps a beam from the spatial light modulator and a beam from the reflecting optical member at least in part.

5. The illumination optical apparatus according claim 2, wherein the spatial light modulation device comprises:

a first spatial light modulator with a plurality of optical elements arranged two-dimensionally and driven individually on the first optical path; and

a second spatial light modulator with a plurality of optical elements arranged two-dimensionally and driven individually on the second optical path, and

wherein the controller overlaps a beam from the first spatial light modulator and a beam from the second spatial light modulator at least in part, and adjusts a polarization state of a resultant beam to a polarization state different from polarization states of the beams incident to the first and second spatial light modulators.

6. The illumination optical apparatus according to claim 5, comprising:

a condensing optical system to condense the beams from the first and second spatial light modulators;

a fly'"'"'s eye lens arranged between the condensing optical system and the illumination target surface; and

a condenser optical system to guide light from the fly'"'"'s eye lens to the illumination target surface,

wherein the surface where the beams from the first and second spatial light modulators are overlapped at least in part is an entrance surface of the fly'"'"'s eye lens.

7. The illumination optical apparatus according to claim 5, wherein the controller controls a ratio of light quantities of the beam from the first spatial light modulator and the beam from the second spatial light modulator, on an overlapping surface where the beam from the first spatial light modulator and the beam from the second spatial light modulator are overlapped at least in part.

8. The illumination optical apparatus according to claim 7, wherein the controller controls n1 (n1 is an integer of one or more) optical elements of the optical elements in the first spatial light modulator and n2 (n2 is an integer of one or more) optical elements of the optical elements in the second spatial light modulator, so as to control the light quantity ratio to n1:

n2 being a ratio of the numbers of the optical elements.

9. The illumination optical apparatus according to claim 7, wherein the controller controls an optical path length difference between at least parts of the beams from the first and second spatial light modulators which are incident to the overlapping surface.

10. The illumination optical apparatus according to claim 6, wherein the plurality of optical elements in the second spatial light modulator include reflecting elements with inclination angles and heights controllable, and

wherein the controller controls the heights of the reflecting elements in the second spatial light modulator.

11. The illumination optical apparatus according to claim 7, wherein the spatial light modulation device further comprises third and fourth spatial light modulators with a plurality of optical elements arranged two-dimensionally on respective optical paths of third and fourth beams out of the plurality of beams,

wherein the light splitting device sets the first, second, third, and fourth beams to linearly polarized light beams with polarization directions being approximately 0°

, 90°

, 45°

, and 135°

directions, and

wherein the controller overlaps the beams from the first, second, third, and fourth spatial light modulators at least in part on the overlapping surface.

12. The illumination optical apparatus according to claim 11, wherein the plurality of optical elements in the first, second, third, and fourth spatial light modulators include mirror elements with variable inclination angles.

13. The illumination optical apparatus according to claim 1, comprising a polarization state measuring device for measuring a polarization state of the beam to illuminate the illumination target surface, which is arranged so as to be freely inserted into and retracted from an optical path of the beam.

14. An exposure apparatus comprising the illumination optical apparatus as set forth in claim 1 for illuminating a predetermined pattern, which is configured to expose a substrate with the predetermined pattern.

15. A device manufacturing method comprising:

exposing the substrate with the predetermined pattern, using the exposure apparatus as set forth in claim 14; and

processing the substrate thus exposed.

16. The illumination optical apparatus according to claim 1, wherein the spatial light modulation device comprises one or more optical surfaces arranged on a plane crossing the optical path on which the spatial light modulation is arranged, and adjusts the phase difference by changing a position of at least one of the optical surfaces in a traveling direction of the beam, said beam traveling in the optical path on which the spatial light modulation is arranged.

17. The illumination optical apparatus according to claim 16, wherein the spatial light modulation device has a plurality of optical elements arranged two-dimensionally and driven individually.

18. An illumination method of illuminating an illumination target surface through use of a beam, comprising:

setting a target distribution of polarization states of the beam, between a spatial light modulation device with a plurality of optical elements arranged two-dimensionally and driven individually, and the illumination target surface;

splitting the beam into a plurality of beams with respective polarization states different from each other;

supplying at least one of first and second beams out of the plurality of beams to the spatial light modulation device;

controlling the spatial light modulation device to change a phase difference between the first beam and the second beam; and

overlapping the first beam and the second beam at least in part and adjusting a polarization state of a resultant beam so as to be different from the polarization states of the beams resulting from the splitting.

19. The illumination method according to claim 18, wherein the target distribution of polarization states is set between first and second spatial light modulators of the spatial light modulation device and the illumination target surface,

wherein the first beam and the second beam are supplied to the first and second spatial light modulators, respectively, and

wherein the polarization state of the resultant beam is adjusted to a polarization state different from the polarization states of the beams incident to the first and second spatial light modulators, by overlapping a beam from the first spatial light modulator and a beam from the second spatial light modulator at least in part.

20. The illumination method according to claim 19, wherein when the beams from the first and second spatial light modulators are overlapped at least in part, at least one of a ratio of light quantities of the beams from the first and second spatial light modulators and an optical path length difference between the beams is controlled.

21. The illumination method according to claim 19, wherein the target distribution of polarization states of the beam is set on an entrance surface of a fly'"'"'s eye lens to which the beams from the first and second spatial light modulators are guided through a condensing optical system.

22. An exposure method comprising:

illuminating a pattern on the illumination target surface by the illumination method as set forth in claim 18; and

exposing a substrate with the pattern.

23. A device manufacturing method comprising:

exposing the substrate with the predetermined pattern, using the exposure method as set forth in claim 22; and

processing the substrate thus exposed.