Tailored extreme ultraviolet (EUV) multilayer systems have been designed, fabricated and characterized for applications as optical key components for guiding or monochromatizing ultrashort sub-femtosecond EUV pulses emitted from Ti:Sa laser-driven high harmonic sources. While spectral filtering of individual harmonic requires a periodic multilayer mirror exhibiting a small reflection bandwidth < 3 eV to separate adjacent harmonics, the reflection of attosecond EUV pulses without compromising the time structure of the pulse requires aperiodic multilayer systems with large reflection bandwidth and optimized phase. Experimental results of the measured EUV reflection properties for a small-bandwidth multilayer are presented as well as the optimization procedure, the fabrication process and structural characterization of an aperiodic broadband EUV multilayer mirror. (C) 2004 Elsevier B.V. All rights reserved.