Patent ID: 7463423

Claim:
Lithography projection objective for imaging a pattern to be arranged in an object plane of the projection objective onto a substrate to be arranged in an image plane of the projection objective, comprising a multiplicity of optical elements that are arranged along an optical axis of the projection objective, the optical elements comprising a first group, following the object plane, of optical elements, and a last optical element, which follows the first group and is next to the image plane and which defines an exit surface of the projection objective and is arranged at a working distance from the image plane, the projection objective being tunable or tuned with respect to aberrations for the case that the volume between the last optical element and the image plane is filled by an immersion medium with a refractive index substantially greater than 1, and it being possible to adjust the position of the last optical element in the direction of the optical axis, and comprising a positioning device that positions at least the last optical element during immersion operation such that aberrations induced by disturbance are at least partially compensated.