RBS Thickness Analysis of Multilayer Mo/Si Thin Films Deposited by RF Magnetron Sputtering

Molybdenum and silicon multilayer systems exhibit particularly high reflectivities in the 1-30 nm EUV spectral range for nearnormal
incidence operation. They have found applications in astronomy to study the solar corona and could eventually be used as
optical components for EUV projection lithography. To attain high reflectivity values, one must rely on effective designs for the
superlattice as well as on an accurate metrology system to determine the thickness of each individual layer. These Mo/Si multilayers
were deposited at room temperature on polyimide substrate using RF magnetron sputtering in a 5X10-3 mbar Ar atmosphere at
constant power of 1.5 W/cm2. We will present here the results of thickness multilayer determination by means of normal and
grazing angle RBS analysis as well as the limits of the method for this kind of material.