Patent attributes
A catoptric projection optical system for projecting a reduced size of a pattern on an object surface onto an image surface includes eight mirrors and forms an intermediate image between the sixth mirror and the seventh mirror on an optical path, wherein a position in a height direction of a principal ray from an optical axis at each mirror displaces, and a displacement direction from the first mirror to the fourth mirror is reverse to that from the fifth mirror to the eight mirror, wherein the second mirror to the fifth mirror are a concave mirror, a convex mirror, a concave mirror and a concave mirror, and the seventh mirror to the eighth are a convex mirror and a concave mirror, and wherein the second mirror of the eight mirrors is located closest to the object surface side.
