Patent ID: 8908269

Claim:
A catadioptric projection objective for imaging a pattern provided in an object plane of the projection objective onto an image plane of the projection objective comprising: a first objective part to image the pattern provided in the object plane to a first intermediate image, wherein all of the elements in the first objective part having optical power to image the pattern provided in the object plane to the first intermediate image are refractive elements; a second objective part that comprises at least one concave mirror to image the first intermediate image to a second intermediate image; and a third objective part to image the second intermediate image to the image plane, wherein all of the elements in the third objective part having optical power to image the second intermediate image to the image plane are refractive elements; wherein the third objective part comprises at least two negative lenses, wherein two of the negative lenses each have a concave surface facing the image plane, wherein an aperture stop is positioned in the third objective part, wherein there are no more than four lenses in the third objective part between the aperture stop and the image plane, and wherein the projection objective has an image-side numerical aperture NA of at least 1.2 when water is used as an immersion fluid between the third objective part and the image plane.