EUV multilayer coated mirrors for atto-physics, photolithography and space experiments: Software design procedure

Extreme ultraviolet multilayer coatings consist of periodic or aperiodic stack of two or more material layers in the nanometric scale. They are fundamental in a very wide range of applications: in atto-physics they allow manipulation of high order harmonics by compressing ultrafast pulses in the atto-second regime; in the free electron laser beamlines they can be used to select the proper harmonics while rejecting unwanted ones; in space experiments they are employed in astrophysical instrumentation dedicated to space weather studies for the observation of solar disk and coronal plasmas; in microelectronics industry they are used as coatings of mirrors and projection masks in extreme ultraviolet lithographic apparatus for integrated circuit production. The more and more sophisticated level of such experiments and apparatus required the realization of multilayers with very strict requirements; in particular high control of reflecting curve shape and phase, and stability with respect to deposition process can be achieved only by deposition of aperiodic structure. Optimization of such structures usually requires a quite complex mathematical approach; an innovative software tool to perform such designs is presented.