Patent ID: 7948675
Filing Date: 2011-05-24
Classification: G02B

Abstract:
1. A multilayer-film reflective mirror, comprising: a base including a surface having a surface profile; a multilayer film on the surface of the base, the multilayer film comprising first layers and second layers alternatingly laminated at a prescribed period length, the multilayer film being reflective to incident extreme ultraviolet (EUV) light and including an upper surface having an irregular profile; a third layer covering the upper surface of the multilayer film and having an upper surface, the third layer being formed of a substance having a refractive index to EUV light substantially equal to the refractive index of a vacuum; and a protective layer covering the upper surface of the third layer and forming an interface between the third layer and the protective layer, the interface being the entire region between the third layer and the protective layer and being situated at a height location from the surface of the base, the height location being an integer multiple of the period length.