Illumination optical system, exposure apparatus, and device manufacturing method
AssigneeNikon Corporation
InventorHirohisa Tanaka
Life of this patent
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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.
Claims21
An illumination optical system which illuminates an irradiated plane with illumination light provided from a light source and which is used in combination with a projection optical system for projecting a pattern arranged on the irradiated plane onto a photosensitive substrate, the illumination optical system comprising:
- a diffuser which is arranged in an optical path of the illumination optical system and diffuses the illumination light incident on the diffuser;
- a spatial light modulator which is arranged between the diffuser and the irradiated plane and which includes a plurality of elements two-dimensionally arranged, each of the plurality of elements being controllable independently from one another and the plurality of elements receiving the illumination light diffused by the diffuser;
- a first optical system which is arranged in an optical path between the spatial light modulator and the irradiated plane and which distributes the light from the spatial light modulator to form a desirable light intensity distribution at a position optically conjugated with a pupil position of the projection optical system;
- and
- a second optical system which has an imaging optical system arranged in an optical path between the diffuser and the spatial light modulator.
An illumination method which illuminates an irradiated plane with illumination light provided from a light source and which is used in combination with a projection optical system for projecting a pattern arranged on the irradiated plane onto a photosensitive substrate, the illumination method comprising:
- diffusing with a diffuser the illumination light from the light source;
- guiding the illumination light via the diffuser to a spatial light modulator which has a plurality of elements two-dimensionally arranged in a plane crossing an optical path of the illumination light, each of the plurality of elements being controllable independently from one another;
- and
- distributing the light from the spatial light modulator to form a desirable light intensity distribution at a position optically conjugated with a pupil position of the projection optical system,
- wherein the guiding of the illumination light to the spatial light modulator includes:
- guiding the illumination light via the diffuser to an imaging optical system;
- and
- guiding the illumination light via the imaging optical system to the spatial light modulator.
Dependencies are inferred from the claim text.