Patent ID: 7173759

Claim:
A monochromator mirror for the EUV spectral range having a layer arrangement applied to a substrate and which has a sequence of individual layers, wherein the layer arrangement has a periodic sequence of two individual layers A and B of different materials forming one period with the period thickness d and having the particular layer thickness d A and d B , so that the following applies: 0.97( d A +d B )â‰¦ d â‰¦( d A +d B )1.03 where ( n A d A +n B d B )*cos(Î¸)= m*Î»/ 2, wherein n A and n B are the real parts of the complex refractive indices of the materials of the individual layers A and B, m is a whole number representing the order of Bragg reflection greater than or equal to 2 and Î» is the wavelength of the incident radiation and Î¸ is the angle of incidence of the incident radiation, and wherein also the following applies for the layer thickness ratio â”Œ=d A /d: â”Œ<0.8/ m; and wherein the reduction of the half width of mirror reflection when using a Bragg reflection of the 2 nd order (m=2) with respect to the half width of the mirror reflection when using a Bragg reflection of the 1 st order (m=1) is about the factor 2 .