| 摘要 |
A catadioptric reduction projection optical system having a structure capable of increasing a numerical aperture without increasing the size of a beam splitter and achieves excellent performance of a semiconductor manufacturing apparatus. The catadioptric reduction projection optical system comprises a first partial optical system having a first lens group, the beam splitter, a lens element, and a concave reflecting mirror to form an intermediate image of a first object, a second partial optical system for forming a reduced image of the intermediate image on a second object, the second partial optical system having a second lens group of a positive refracting power and arranged in an optical path between a second object surface and a surface on which the intermediate image is formed, and a third lens group arranged in an optical path between the beam splitter and the third lens group. The first lens group is arranged in an optical path between the first object and the beam splitter. Light from the first object guided to the concave reflecting mirror through the first lens group, the beam splitter, and the second lens group in the order named. Light reflected by the concave reflecting mirror passes through the second lens group and the beam splitter in the order named and is guided to the surface on which the intermediate image is formed. At least a part of the fourth lens group is arranged in an optical path between the beam splitter and the surface.
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