Spatial light modulation unit, illumination optical apparatus, exposure apparatus, and device manufacturing method

• US 8,953,147 B2
• Filed: 03/01/2012
• Issued: 02/10/2015
• Est. Priority Date: 11/08/2007
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Muramatsu, Kouji
• Primary Examiner(s): Kim, Peter B
• Assistant Examiner(s): IACOLETTI, MICHELLE M
• Application Number:
  US13/409,870
• Publication Number:
  US 20120212799A1
• Time in Patent Office: 1,076 Days
• Field of Search: 355/67
• US Class Current: 355/67
• CPC Class Codes: G03F 7/70075 Homogenization of illumination intensity in the mask plane by using an integrator, e.g. fly's eye lens, facet mirror or glass rod, by using a diffusing optical element or by beam deflection
• 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

Abstract

An illumination optical apparatus capable of forming a pupil intensity distribution of desired shape and illuminance and, in turn, capable of realizing illumination conditions of great variety. The apparatus has a spatial light modulation unit composed of a first spatial light modulator and a second spatial light modulator arranged in an order of incidence of light, and a distribution forming optical system to form a predetermined light intensity distribution on an illumination pupil, based on a beam having traveled via the first spatial light modulator and the second spatial light modulator. The first spatial light modulator has a plurality of first optical elements which are two-dimensionally arranged and postures of which each are individually controlled. The second spatial light modulator has a plurality of second optical elements which are two-dimensionally arranged in correspondence to the first optical elements and postures of which each are individually controlled.

Claims

1. An optical system which is used in an exposure apparatus which illuminates a pattern with illumination light from a light source and exposes a photosensitive substrate with light from the pattern, the optical system comprising:

a first spatial light modulator which is arranged on an optical path of the illumination light, has a plurality of first optical elements which are arranged two-dimensionally and postures of which are individually controlled, and modulates light incident thereon to light with a predetermined angle distribution;

a second spatial light modulator which is arranged on the optical path of the illumination light, has a plurality of second optical elements which are arranged two-dimensionally and postures of which are individually controlled, and modulates light incident thereon to light with a predetermined angle distribution;

a distribution forming optical system which makes the illumination light modulated by the first and second spatial light modulators be distributed on a pupil plane, the distribution forming optical system being configured to have a Fourier transform optical system and a two-dimensional light divider which two-dimensionally divides light incident thereon from the Fourier transform optical system; and

a control unit which controls the first and second spatial light modulators so that a position of the light incident on the two-dimensional light divider and the angle of the light incident along the two-dimensional light divider are individually set at predetermined values, and

wherein the pattern is illuminated with illumination light from the pupil plane.

2. The optical system according to claim 1,

wherein no optical member is arranged between the first spatial light modulator and the second spatial light modulator.

3. The optical system according to claim 1,

wherein the distribution forming optical system includes an optical surface array which applies an angle distribution to the illumination light modulated by the first and second spatial light modulators.

4. The optical system according to claim 3,

wherein a plurality of optical surfaces in the optical surface array are arranged on the pupil plane.

5. The optical system according to claim 3, further comprising a condensing optical system which guides the illumination light from the pupil plane to the pattern.

6. The optical system according to claim 5,

wherein the optical surface array includes a fly'"'"'s eye lens.

7. The optical system according to claim 1, further comprising a projection optical system which forms an image of the pattern onto the photosensitive substrate,

wherein the pupil plane is optically conjugate with a pupil plane of the projection optical system.

8. An exposure apparatus configured to illuminate a pattern with illumination light from a light source and expose a photosensitive substrate with light from the pattern, comprising the optical system as set forth in claim 1.

9. An optical system which is used in an exposure apparatus which illuminates a pattern with illumination light from a light source and exposes a photosensitive substrate with light from the pattern, the optical system comprising:

an active spatial light modulator which is arranged on an optical path of the illumination light, has a plurality of optical elements which are arranged two-dimensionally and postures of which are individually controlled, and modulates light incident thereon to light with a predetermined angle distribution;

a spatial light modulator which applies an angle distribution to the illumination light modulated by the active spatial light modulator; and

a distribution forming optical system which makes the illumination light from the spatial light modulator be distributed on a pupil plane, the distribution forming optical system being configured to have a Fourier transform optical system and a two-dimensional light divider which two-dimensionally divides light from the Fourier transform optical system,

wherein the pattern is illuminated with the illumination light from the pupil plane.

10. A device manufacturing method comprising:

illuminating a pattern with illumination light from a light source and exposing a photosensitive substrate with light from the pattern,

forming a mask layer in a shape corresponding to the pattern on a surface of the photosensitive substrate after developing the photosensitive substrate onto which the pattern has been transferred; and

processing a surface of the photosensitive substrate through the mask layer,

wherein the exposing includes;

modulating light incident on a first spatial light modulator with a predetermined angle distribution, the first spatial light modulator being configured to have a plurality of first optical elements which are arranged two-dimensionally and postures of which are individually controlled;

modulating light incident on a second spatial light modulator with a predetermined angle distribution, the second spatial light modulator being configured to have a plurality of second optical elements which are arranged two-dimensionally and postures of which are individually controlled;

illuminating the illumination light modulated by the first and second spatial light modulators onto an optical element array which has a plurality of third optical elements arranged two-dimensionally;

applying an angle distribution to the illumination light modulated by the first and second spatial light modulators;

making the illumination light modulated by the first and second spatial light modulators be distributed on a pupil plane, by using a Fourier transform optical system and the optical element array;

controlling the first and second spatial light modulators so that a position of the light incident on the optical element array and the angle of the light incident on the optical element array are individually set at predetermined values; and

illuminating the pattern with the illumination light from the pupil plane.

11. A device manufacturing method comprising:

illuminating a pattern with illumination light from a light source and exposing a photosensitive substrate with light from the pattern;

forming a mask layer in a shape corresponding to the pattern on a surface of the photosensitive substrate after developing the photosensitive substrate onto which the pattern has been transferred; and

processing a surface of the photosensitive substrate through the mask layer,

wherein the exposing includes;

modulating light incident on an active spatial light modulator with a predetermined angle distribution, the active spatial light modulator being configured to have a plurality of optical elements which are arranged two-dimensionally and postures of which are individually controlled;

applying an angle distribution to the illumination light modulated by the active spatial light modulator; and

making the illumination light modulated by the active spatial light modulator be distributed on a pupil plane, by using a Fourier transform optical system and a two-dimensional light divider which two-dimensionally divides light from the Fourier transform optical system; and

illuminating the pattern with the illumination light from the pupil plane.