Filter device for the compensation of an asymmetric pupil illumination
AssigneeCarl Zeiss SMT GmbH
InventorsManfred Maul, Damian Fiolka
Life of this patent
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Abstract
The invention relates to a filter device for an illumination system, especially for the correction of the illumination of the illuminating pupil, including a light source, with the illumination system being passed through by a bundle of illuminating rays from the light source to an object plane, with the bundle of illuminating rays impinging upon the filter device, including at least one filter element which can be introduced into the beam path of the bundle of illuminating rays, with the filter element including an actuating device, so that the filter element can be brought with the help of the actuating device into the bundle of illuminating rays.
Claims21
An illumination system, comprising:
- a filter device comprising a plurality of filter elements including a first filter element;
- an actuating device configured to displace the first filter element to different positions in a beam path of a bundle of illuminating rays passing through the illumination system during use,
- wherein:
- the filter device is arranged in a distance region Δz relative to a pupil plane of the illumination system;
- a first boundary of the distance region is given by the pupil plane;
- a second boundary of the distance region is given by a ΔZMAX;
- and
- ΔZMAX is defined in so that, at or near the pupil plane, partial shadows of the filter elements overlap by at most half in a circumferential region of the beam.
Dependencies are inferred from the claim text.