Normal-incidence multilayer mirrors

Fig. 9.2. Normal incidence reflectivity for various XUV/SXR mirrors. All of the mirrors, except the SiC mirror, are multilayer-coated. The solid lines show the theoretical values and the plots are measured data...

It must be emphasized that the short attenuation length and low normal-incidence reflectivity of materials in the EUV range present very difficult problems regarding fabricating single-surface mirrors or lenses. The main solution to this problem is the use of multilayer reflectors. Absent these reflectors, EUV lithography as currently practiced would not be possible. 

Figure 14.5 Calculated normal Incidence reflectivity curve for a molybdenum-silicon multilayer mirror with number of bIlayers 50. The molybdenum thickness Is 2.7 nm and the silicon thickness Is 4.2 nm. (Reprinted with permission from Ref. 44. 2009 McGraw-Hill.)...

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