Illumination optical apparatus, exposure apparatus, and device manufacturing method

• US 10,101,666 B2
• Filed: 05/19/2015
• Issued: 10/16/2018
• Est. Priority Date: 10/12/2007
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Hirota, Hiroyuki
• Primary Examiner(s): Kreutzer, Colin
• Application Number:
  US14/716,168
• Publication Number:
  US 20150261096A1
• Time in Patent Office: 1,246 Days
• Field of Search: 355 67, 355 71, 355 77, 359558, 359904
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G03F 7/70083 Non-homogeneous intensity distribution in the mask plane
• 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 7/70158 Diffractive optical elements
• CPC Class Codes: G03F 7/70291 Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices

Abstract

An illumination optical apparatus guides exposure light emitted from an exposure light source, to an illumination target object. The illumination optical apparatus has a plurality of spatial light modulation members arranged in an array form, and each spatial light modulation member is so configured that a plurality of reflecting optical elements each including a movable reflecting surface are arranged in an array form. At least one of the spatial light modulation members is arranged in an optical path of the light emitted from the light source.

Claims

1. An illumination optical system which illuminates a pattern with illumination light, the illumination optical system comprising:

an optical element having a plurality of wavefront division regions arranged in an optical path of the illumination light, the plurality of wavefront division regions dividing the illumination light into a plurality of beams;

a spatial light modulator having a plurality of movable mirrors arranged in array form so as to reflect the illumination light from the optical element; and

a distribution forming optical system arranged in the optical path of the illumination light from the spatial light modulator so as to form a predetermined light intensity distribution on an illumination pupil plane of the illumination optical system,

wherein the optical element directs the plurality of beams to an area on the spatial light modulator such that the plurality of beams from the plurality of wavefront division regions overlap in illuminating the area including the plurality of movable mirrors, and

the optical element directs a first part of the plurality of beams from a first part of the plurality of wavefront division regions to a first part of the area so as to superposedly illuminate the first part of the area by the first part of the beams and directs a second part of the plurality of beams from a second part of the plurality of wavefront division regions to a second part of the area so as to superposedly illuminate the second part of the area by the second part of the beams, the first part of the area and the second part of the area being different from each other.

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

the optical element comprises a transmission type diffractive optical element.

3. An exposure apparatus comprising:

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

a projection optical apparatus which projects an image of the pattern onto a substrate to which a photosensitive material is applied.

4. A device manufacturing method comprising:

exposing the substrate with the pattern by using the exposure apparatus according to claim 3;

developing the substrate to form a mask layer having a shape corresponding to the pattern on a surface of the substrate; and

processing the surface of the substrate through the mask layer.

5. The illumination optical system according to claim 1, wherein

first movable mirrors which are a part of the plurality of movable mirrors located in the first part of the area have a first reflecting surface of which an inclination angle to an optical axis of the illumination optical system is adjustable, the first reflecting surface being rotatable about a first rotational axis, and

second movable mirrors which are another part of the plurality of movable mirrors located in the second part of the area have a second reflecting surface of which an inclination angle to the optical axis is adjustable, the second reflecting surface being rotatable about a second rotational axis different from the first rotational axis.

6. The illumination optical system according to claim 5, wherein

the first and second rotational axes are substantially perpendicular to each other.

7. The illumination optical system according to claim 5, wherein

the first movable mirrors reflect the first part of the beams so as to direct the first part of the beams to a first distribution area on the illumination pupil plane via the distribution forming optical system, and the second movable mirrors reflect the second part of the beams so as to direct the second part of the beams to a second distribution area on the illumination pupil plane via the distribution optical system, the first and second distribution areas being different from each other.

8. The illumination optical system according to claim 7, wherein

the first and second distribution areas are located on opposite sides from each other with respect to the optical axis on the illumination pupil plane.

9. The illumination optical system according to claim 1, wherein

the distribution forming optical system comprises a lens system and a fly'"'"'s eye lens of which an entrance surface is located at or near a rear focal position of the lens system.

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

the fly'"'"'s eye lens is arranged such that a rear focal plane of the fly'"'"'s eye lens is coincident with the illumination pupil plane.

11. An exposure method comprising:

illuminating the pattern by use of the illumination optical system according to claim 1; and

projecting an image of the pattern onto a substrate to which a photosensitive material is applied.

12. A device manufacturing method comprising:

exposing the substrate with the pattern by using the exposure method according to claim 11;

developing the substrate to form a mask layer having a shape corresponding to the pattern on a surface of the substrate; and

processing the surface of the substrate through the mask layer.