ILLUMINATION OPTICAL SYSTEM, EXPOSURE APPARATUS, AND DEVICE MANUFACTURING METHOD

• US 20090097007A1
• Filed: 10/15/2008
• Published: 04/16/2009
• Est. Priority Date: 10/16/2007
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Tanaka, Hirohisa
• Granted Patent: US 8,462,317 B2
• Time in Patent Office: Days
• 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 7/70108 Off-axis setting using a light-guiding element, e.g. diffractive optical elements [DOEs] or light guides
• 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 system for illuminating an irradiated plane M with illumination light provided from a light source includes a spatial light modulator, which is arranged in an optical path of the illumination optical system and forms a desired light intensity distribution at a pupil position of the illumination optical system or a position optically conjugated with the pupil position, and a diffuser, which is arranged at an incidence side of the spatial light modulator through which the illumination light enters.

Claims

1. An illumination optical system which illuminates an irradiated plane with illumination light provided from a light source, the illumination optical system comprising:

a spatial light modulator which is arranged in an optical path of the illumination optical system and forms a desired light intensity distribution at a pupil position of the illumination optical system or a position optically conjugated with the pupil position; and

a diffuser which is arranged at an incidence side of the spatial light modulator through which the illumination light enters and diffuses the illumination light entering the spatial light modulator.

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

the spatial light modulator includes a plurality of two-dimensionally arranged elements which receive the illumination light diffused by the diffuser; and

the plurality of elements are controllable independently from one another.

3. The illumination optical system according to claim 2, wherein:

the plurality of elements each includes a reflection surface; and

the reflection surfaces of the plurality of elements are controllable independently from one another.

4. The illumination optical system according to claim 1, further comprising:

an optical member which is arranged in an optical path between the diffuser and the spatial light modulator and which transforms the illumination light diffused by the diffuser to astringent light and provides the astringent light to the spatial light modulator.

5. The illumination optical system according to claim 4, wherein the optical member includes an imaging optical system.

6. The illumination optical system according to claim 1, wherein the diffuser isotropically diffuses the incident illumination light.

7. The illumination optical system according to claim 1, wherein the diffuser anisotropically diffuses the incident illumination light.

8. An exposure apparatus which transfers a pattern of a mask onto a photosensitive substrate, the exposure apparatus comprising:

the illumination optical system according to claim 1 which illuminates the mask that is arranged on an irradiated plane.

9. A device manufacturing method comprising:

exposing a pattern of a mask onto a photosensitive substrate using the exposure apparatus according to claim 8;

developing the photosensitive substrate onto which the pattern has been transferred to form a mask layer shaped in correspondence with the pattern on a surface of the photosensitive substrate; and

processing the surface of the photosensitive substrate through the mask layer.

10. The illumination optical system according to claim 2, wherein the diffuser isotropically diffuses the incident illumination light.

11. The illumination optical system according to claim 2, wherein the diffuser anisotropically diffuses the incident illumination light.

12. An exposure apparatus which transfers a pattern of a mask onto a photosensitive substrate, the exposure apparatus comprising:

the illumination optical system according to claim 2 which illuminates the mask that is arranged on an irradiated plane.

13. A device manufacturing method comprising:

exposing a pattern of a mask onto a photosensitive substrate using the exposure apparatus according to claim 12;

developing the photosensitive substrate onto which the pattern has been transferred to form a mask layer shaped in correspondence with the pattern on a surface of the photosensitive substrate; and

processing the surface of the photosensitive substrate through the mask layer.