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US 11,079,604 B2Granted
Device for determining the exposure energy during the exposure of an element in an optical system, in particular for microlithography
AssigneeCarl Zeiss SMT GmbH
InventorThomas Frank
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Abstract
The invention relates to a device for determining the exposure energy during the exposure of an element in an optical system, in particular for microlithography, comprising an optical element, a diffractive structure which has a locally varying grating period, and an intensity sensor arrangement, wherein electromagnetic radiation diffracted at the diffractive structure during operation of the optical system, in at least one order of diffraction, is directed to the intensity sensor arrangement by way of total internal reflection effected in the optical element.
Claims21
A system comprising:
- a light source;
- an illumination optical unit configured to project light from the light source towards a first element;
- a first detector unit;
- an imaging optical unit configured to project light from the first element towards the first detector unit;
- an exposure determining device disposed between the illumination optical unit and the first element, the exposure determining device comprising:
- a first optical element;
- a diffractive structure;
- and
- a second detector unit;
- wherein the exposure determining device is configured such that light diffracted at the diffractive structure during operation of the system, in at least one order of diffraction, is directed to the second detector unit by total internal reflection in the first optical element.
7 more elements
Dependencies are inferred from the claim text.