Patent ID: 7706058

Claim:
A multilayer mirror comprising a reflective multilayer in which a high refractive-index film and a low refractive-index film are laminated on a substrate by turns under a condition that a Bragg's reflection condition holds that reflected light from a plurality of boundary surfaces of the high refractive-index film and low-refractive index film for EUV ray is put in phase, comprising: an interposed layer having a thickness of half or more of a center wavelength of the EUV ray, wherein a band of EUV ray wavelength or a range of incidence angle both having a relatively high EUV ray reflectivity is widened, and each layer is laminated while the film thickness thereof is varied arbitrarily so the reflectivity for light having a wavelength of 13.1 nm to 13.9 nm is set to 45% or more.