Exposure apparatus that illuminates a mark and causes light from the mark to be incident on a projection optical system

摘要

An exposure apparatus wherein a first object is illuminated with slit-like exposure light while the first object and a second object are scanningly moved at a speed ratio corresponding to a projection magnification of a projection optical system such that a pattern of the first object is projected onto the second object through the projection optical system. The apparatus includes an illuminating device for illuminating a mark provided on the first object side with light having the same wavelength as that of the exposure light, wherein light from the mark is incident on the projection optical system whereby a revolutionally asymmetric aberration of the projection optical system due to an exposure is corrected or reduced.