Fish & Richardson P.C.
Catadioptric projection objective
A method of providing a catadioptric projection includes: providing a first partial objective for imaging an object field onto a first real intermediate image; providing a second partial objective for imaging the first real intermediate image onto a second real intermediate image, in which the second partial objective includes a concave mirror; providing a third partial objective for imaging the second intermediate image onto an image field, the third partial objective including an aperture stop; providing a first folding mirror and a second folding mirror; and providing an antireflection coating onto a surface of at least one lens that is directly adjacent to the concave mirror or that is separate from the concave mirror by a single lens, in which the antireflection coating is designed to have reflectivity of less than 0.2% for a wavelength between 150 nm and 250 nm and for an angle-of-incidence range between 0° and 30°.
Carl Zeiss SMT GmbH
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G02B G02B G02B G03F G03F G03F G02B
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Thomas Toralf Alexander Vladimir
Schicketanz Gruner Epple Kamenov