ILLUMINATING OPTICAL SYSTEM, EXPOSURE SYSTEM AND EXPOSURE METHOD

摘要

An illuminating optical system substantially free from micro-channel in a diffractive optics disposed on the optical path of a laser beam having a high energy density. An illuminating optical system having a light source (1) for supplying a pulse laser beam that is used to illuminate a surface to be illuminated (M). A diffractive optics (4) disposed on an optical path is provided, the optical path being provided between a light source and a surface to be illuminated to allow a light flux having an energy density of at least 1 mJ/cm<2>/pulse to pass through. The diffractive optics is formed of an oxide crystal material such as quartz.