| 摘要 |
<p>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 comprises: an optical axis, a plurality of lenses and at least one concave mirror having a continuous mirror surface having no hole in the area of a footprints of the radiation beam on the reflecting surfaces. The projection objective is an unobscured system having no pupil obscuration. Further, the projection objective has negative isotropic magnification such that an object field disposed on one side of the optical axis is imaged into an image field disposed on the opposite side of the optical axis without image flip, whereby no change of chirality occurs between the object field and the image field. This allows to use the same type of reticles also used for imaging with refractive projection objectives.</p> |
