Spectral filter, lithographic apparatus including such a spectral filter, device manufacturing method, and device manufactured thereby.

摘要

A lithographic spectral filter including a first filter element including a slit having an in plane length dimension arranged in a first direction; and a second filter element arranged at a subsequent position along an optical path of radiation of first and second wavelengths to the first filter element, the second filter element including a slit having an in plane length dimension arranged in a second direction transverse to the first direction, wherein the spectral filter is configured to reflect radiation of a first wavelength and allow transmission of radiation of a second wavelength, the first wavelength being larger than the second wavelength.