DIFFRACTION OPTICAL ELEMENT, OPTICAL SYSTEM EQUIPPED WITH DIFFRACTION OPTICAL ELEMENT, MANUFACTURE OF DIFFRACTION OPTICAL ELEMENT, EXPOSURE DEVICE INCLUDING OPTICAL SYSTEM EQUIPPED WITH DIFFRACTION OPTICAL ELEMENT AND MANUFACTURE OF DEVICE BY USING EXPOSURE DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a diffraction optical element having high optical performance, capable of realizing, easily and surely, an optical function equivalent to a high-precision optical element requiring an extreme minute pattern, and capable of suppressing generation of unnecessary diffracted light or stray light. SOLUTION: Optical elements 31, 32 are joined and fixed by positioning so as to be contacted on diffraction patterns 31b, 32b, and this diffraction optical element 21 is composed by the weight function of both diffraction patterns 31b, 32b, so as to be substantially equivalent to a diffraction optical element equipped with an eight-step pattern, by paying attention to the optical path length of a ray passing through the parts of each step composing the diffraction patterns.