PROJECTION OPTICAL SYSTEM, EXPOSURE APPARATUS AND DEVICE FABRICATING METHOD

摘要

A projection optical system is provided for projecting a pattern on an object plane onto an image plane in a reduced size. The projection optical system has six reflective surfaces that include, in order of reflecting light from the object plane, a first reflective surface, a second convex reflective surface, a third convex reflective surface, a fourth reflective surface, a fifth reflective surface and a sixth reflective surface. An aperture stop is provided along an optical path between the first and second reflective surfaces. The following condition is met by the system, where L1 is an interval between the object plane and the surface apex that is the closest to the object plane, and L2 is an interval between the surface apex of the first reflective surface and the surface apex that is the closest to the object plane: $0.75<\frac{L1}{L2}<1.25.$