Illuminating and imaging system comprising a diffractive beam splitter

摘要

The invention relates to an imaging system in which a diffractive optical element is used by both the illumination beam path and the imaging beam path. Said diffractive element operates in the reflection mode or transmission mode according to the specifications of the system design. At least one of the imaging optical elements provided in the beam path of the inventive diffractive beam splitter for imaging systems is used for both the illumination beam path and the imaging beam path. Said element represents a diffractive optical element (DOE) and requires no spatial separation between the imaging beam path and the illumination beam path in the object space by using different diffraction arrays. The number of reflective optical elements can be decreased by using diffractive optical elements, resulting in the cost of the system being reduced and the service life of the optical components being increased by using a low-power EUV source.