ECHELLE DIFFRACTION GRATING, EXCIMER LASER, ECHELLE DIFFRACTION GRATING MANUFACTURING METHOD AND ARGON FLUORIDE EXCIMER LASER

摘要

PROBLEM TO BE SOLVED: To provide an echelle diffraction grating used for an argon fluoride excimer laser and capable of maintaining a diffraction efficiency over long term use.SOLUTION: In an echelle diffraction grating 1, each grating includes: a resin layer 11 having thickness of 2 m-10 m; and a reflection film layer 12 formed on the resin layer, having thickness of 120 nm-500 nm, and made of aluminum. The echelle diffraction grating 1 has a Littrow arrangement, an apex angle of 85° or more, and less than 90°. A blaze angle thereof has, as an initial value, a second blaze angle smaller than a first blaze angle that makes a maximum diffraction efficiency of a blaze order set to incident light of wavelength 193.3 nm. If the first blaze angle is regarded as bd, and the second blaze angle is regarded as ba, 0.25°bd-ba1.2° is satisfied.