CATADIOPTRIC PROJECTION OBJECTIVE LENS

摘要

PROBLEM TO BE SOLVED: To provide a catadioptric projection objective lens suitable for use in a vacuum ultraviolet (VUV) range having potential for very high image side numerical aperture which can be extended to values allowing immersion lithography at numerical apertures NA>1.

SOLUTION: The catadioptric projection objective lens for imaging a pattern provided in the object plane of the projection objective lens onto the image plane of the projection objective lens has a first objective lens part for imaging the pattern provided in the object plane into a first intermediate image, a second objective lens part for imaging the first intermediate image into a second intermediate image and a third objective lens part for imaging the second intermediate image onto the image plane. The projection objective lens has two mirrors and two intermediate images exactly and the projection objective lens has a clear form having no unclearness of a pupil.

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