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US 7,453,643 B2Granted
Blazed diffractive optical element and projection objective for a microlithographic projection exposure apparatus
AssigneeCarl Zeiss SMT GmbH
InventorBernd Kleemann
Life of this patent
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Abstract
A diffractive optical element has a support and a plurality of diffraction structures. The latter are applied on the support and are binary blazed by being split into substructures so that the aspect ratio of the substructures varies locally within an individual diffraction structure. One or more substructures with a large aspect ratio inside an individual diffraction structure are replaced by at least one substitute structure whose aspect ratio is less than that of the replaced substructures.
Claims8
A diffractive optical element, comprising:
- a support and
- a plurality of diffraction structures which
- are applied on the support and
- are binary blazed by being split into substructures so that the aspect ratio of the substructures varies locally within an individual diffraction structure,
- wherein one or more substructures inside an individual diffraction structure are replaced by at least one substitute structure whose aspect ratio is less than that of the replaced substructures.
2 more elements
Dependencies are inferred from the claim text.