OPTICAL ELEMENT FOR EXTREMELY SHORT ULTRAVIOLET OPTICAL SYSTEM AND EXTREMELY SHORT ULTRAVIOLET EXPOSURE DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical element for extremely short ultraviolet optical system wherein rarely reflective characteristic varies since oxidation reaction does not occur easily.;SOLUTION: A reflective mirror is constituted so that a reflection film 4 may be formed by laminating alternately a Mo thin film 2 with a low refraction substance and an Si thin film 3 with a high refraction substance on a substrate 1. Further, a protective film 5 consisting of one substance of niobium, rhodium, passive metal, nitride, fluoride, and carbide is formed on the reflection film 4. The mixture of these substances arbitrarily may be used as the protective film 5.;COPYRIGHT: (C)2006,JPO&NCIPI