Optical unit, illumination optical apparatus, exposure apparatus, and device manufacturing method

• US 9,857,599 B2
• Filed: 03/24/2016
• Issued: 01/02/2018
• Est. Priority Date: 10/24/2007
• Status: Expired due to Fees

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Tanitsu, Osamu
• Primary Examiner(s): NGUYEN, HUNG
• Application Number:
  US15/079,793
• Publication Number:
  US 20160209664A1
• Time in Patent Office: 649 Days
• Field of Search: 355 53, 355 67- 71
• CPC Class Codes: F21V 13/02 Combinations of only two kinds of elements
• CPC Class Codes: F21V 14/003 by interposition of elements with electrically controlled variable light transmissivity, e.g. liquid crystal elements or electrochromic devices
• CPC Class Codes: F21V 9/14 for producing polarised light
• CPC Class Codes: G02B 27/0927 Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
• CPC Class Codes: G02B 27/0938 Using specific optical elements
• CPC Class Codes: G02B 27/1086 operating by diffraction only
• CPC Class Codes: G02B 27/126 The splitting element being a prism or prismatic array, including systems based on total internal reflection
• 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: G03F 7/70058 Mask illumination systems
• 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 7/70566 Polarisation control

Abstract

An illumination optical apparatus has an optical unit. The optical unit has a light splitter to split an incident beam into two beams; a first spatial light modulator which can be arranged in an optical path of a first beam; a second spatial light modulator which can be arranged in an optical path of a second beam; and a light combiner which combines a beam having passed via the first spatial light modulator, with a beam having passed via the second spatial light modulator; each of the first spatial light modulator and the second spatial light modulator has a plurality of optical elements arranged two-dimensionally and controlled individually.

Claims

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

an optical integrator arranged in an optical path of the illumination light;

a spatial light modulator which includes a plurality of optical elements arranged along a predetermined plane and arranged in the optical path on an incident side of the optical integrator, and which forms a light intensity distribution of the illumination light on an illumination pupil of the illumination optical apparatus via the optical integrator by driving the plurality of optical elements; and

a polarization element arranged in the optical path, which changes a polarization state of the illumination light, wherein

the spatial light modulator forms the light intensity distribution so that first and second light beams of the illumination light pass through first and second regions of the illumination pupil respectively, the first light beam being incident on a first part of the plurality of optical elements, the second light beam being incident on a second part of the plurality of optical elements, the first part being different from the second part, and

the polarization element includes a first member which is removably disposed in an optical path of the first light beam so as not to cross an optical path of the second light beam.

2. The illumination optical apparatus according to claim 1, wherein

the first member rotates a polarization direction of the first light beam so that the first light beam has a circumferential polarization state in the first region.

3. The illumination optical apparatus according to claim 1, wherein

the first member comprises a half wave plate or an optical rotator.

4. The illumination optical apparatus according to claim 1, wherein

the polarization element comprises a second member provided in the optical path of the second light beam which enters into a reflecting surface of the second part, and the second member rotates the polarization direction of the second light beam so that the polarization state of the second light beam entering the second member with a polarization state in which the linearly polarized light thereof in a predetermined direction is a principle component has a circumferential polarization state in the second region.

5. The illumination optical apparatus according to claim 4, wherein

the second member rotates a polarization direction of the second light beam so that the polarization direction of the second light beam in the second region becomes a direction perpendicular to a polarization direction of the first light beam in the first region.

6. The illumination optical apparatus according to claim 4, wherein

the second member is removably disposed in the optical path of the second light beam.

7. The illumination optical apparatus according to claim 6, wherein

the second member is provided replacably with a glass plate having the same optical length as that of the second member.

8. The illumination optical apparatus according to claim 4, wherein

the second member comprises a half wave plate or an optical rotator.

9. The illumination optical apparatus according to claim 1, further comprising

a polarization control member capable of changing the polarization state of the illumination light in the optical path of the illumination light located on an incident side of the polarization element.

10. The illumination optical apparatus according to claim 9, wherein

the polarization control member comprises a half wave plate which is arranged as rotatable around an axis parallel to an optical axis.

11. The illumination optical apparatus according to claim 1, wherein

the first and second regions are included in a multipolar region or an annular region in the illumination pupil.

12. The illumination optical apparatus according to claim 11, wherein

the first region includes two regions which are separated in a first direction with respect to an optical axis in the illumination pupil, and the second region includes two regions which are separated in a second direction different from the first direction with respect to the optical axis in the illumination pupil.

13. The illumination optical apparatus according to claim 1, further comprising

a lens system which is arranged in the optical path of the illumination light between the spatial light modulator and a fly'"'"'s eye lens and sets an entrance surface of the spatial light modulator and the fly'"'"'s eye lens in the Fourier transform relation.

14. The illumination optical apparatus according to claim 1, wherein

the spatial light modulator sets directions of a plurality of reflecting surfaces so that the illumination light is distributed so as to have a multipolar or annular shape in entrance surfaces of fly'"'"'s eye lenses.

15. An exposure apparatus which projects and exposes a pattern formed on a mask onto a substrate, comprising:

a stage which movably holds the substrate;

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

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

16. The exposure apparatus according to claim 15, wherein

the illumination pupil of the illumination optical apparatus is arranged at a position optically conjugate with an entrance pupil of the projection optical system.

17. The exposure apparatus according to claim 16, further comprising

a liquid supply apparatus which supplies liquid between the substrate held by the stage and the projection optical system, the image of the pattern being formed on the substrate through the liquid supplied by the liquid supply apparatus.

18. A device manufacturing method comprising:

effecting exposure of the pattern formed on the mask on the substrate, using the exposure apparatus as set forth in claim 15, and

developing the substrate onto which the pattern has been transferred.