Patent ID: 6169627
Filing Date: 2001-01-02
Classification: G02B,G03F

Abstract:
A catadioptric microlithographic reduction objective defining an optical axis, providing a light path and forming an image of an object, the catadioptric microlithographic reduction objective comprising: two concave mirrors mounted on said optical axis facing each other; each of said concave mirrors having a configuration symmetrical to the optical axis and having a central bore; a plurality of lenses being arranged along said optical axis toward said image downstream of said concave mirrors on said light path; said concave mirrors conjointly defining an intermediate space therebetween; said plurality of lenses being a first plurality of lenses; said reduction objective further including a second plurality of lenses arranged on said optical axis upstream of said first plurality of lenses and facing toward said object; said second plurality of lenses extending at least partially into said intermediate space; said second plurality of lenses, said concave mirrors and a portion of said first plurality of lenses conjointly forming an intermediate image (Z) of said object on said optical axis downstream of said concave mirrors; and, two lenses of said first plurality conjointly defining a convex air lens therebetween downstream of said intermediate image.