CATADIOPTRIC MULTI-MIRROR SYSTEMS FOR PROJECTION LITHOGRAPHY

摘要

According to one exemplary embodiment, a photolithographic reduction projection catadioptric objective is provided and includes a first optical group (G1) and a second substantially refractive optical group (G2) more image forward than the first optical group (G1). The second optical group (G2) includes a number of lens elements (E4-E 16) and has a negative overall magnifying power for providing image reduction. The first optical group (G1) has a folded geometry for producing a virtual image and the second optical group (G2) receives and reduces the virtual image to form an image with a numerical aperture of at least substantially (0.80).