Abstract: A projection exposure apparatus has a pattern lighting optical system including an exposure light source for lighting a pattern on a photomask, a projection optical system for forming an image of the pattern lighted by the exposure light source on the surface of a wafer, an alignment lighting optical system including an alignment light source for lighting alignment marks on the photomask and the wafer, and an alignment optical system for detecting relative positional relationship between the mask pattern and the wafer through the projection optical system, and further the projection optical system includes an image-forming system which exhibits two extremums of axial aberration as a function of wavelength.

Abstract: A projection type exposure apparatus for projecting an image of a pattern formed on a reticle onto a wafer in which the exposure is carried out with first light and the alignment between reticle and wafer is carried out with a second light having a wavelength different from that of the first light. The apparatus includes an optical member disposed between alignment optical system and projection optical system for reflecting the first light and transmitting the second light.

Abstract: A projection optical apparatus comprises illuminating means providing for an illuminating light beam, a projection optical system including optical elements disposed across the illuminating light beam and having an imaging plane, and detecting mean including temperature sensor means provided on at least one of the optical elements and producing an output corresponding to the temperature of the one optical element.