| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a catadioptric projection objective with potential for very high image-side NA. <P>SOLUTION: A catadioptric projection objective for imaging a pattern provided in an object surface onto an image surface thereof has an object-side imaging subsystem for creating a final intermediate image closest to the image surface from radiation coming from the object surface and an image-side imaging subsystem for directly imaging the final intermediate image into the image surface. The image-side imaging subsystem includes a last optical element closest to the image surface and is designed for creating a convergent beam having an aperture sinα≥0.8 in the last optical element. The image-side imaging subsystem includes, in this order along a propagation direction of radiation: a primary negative lens group having overall negative refractive power; an intermediate positive lens group having overall positive refractive power; a secondary negative lens group having overall negative refractive power; and a final positive lens group having overall positive refractive power and including the last optical element, where the last optical element has a convex entry surface having a radius R<SB>LOE</SB>of curvature with R<SB>LOE</SB>/NA<40 mm. <P>COPYRIGHT: (C)2008,JPO&INPIT |
