Analysis of multilayer structure for reflection of extreme ultra-violet wavelength

Extreme ultraviolet lithography (EUVL) is considered to be one of the most competitive next generation lithography (NGL) technologies (Gwyn et al, 1998). In EUVL, reflective multilayers are used for mask and mirror applications in the exposure system. The reflectivity of these multilayers, which is a critical factor for throughput of EUVL, is dependent on structural factors as well as the materials. Even though the at-wavelength reflectivity should be measured, we usually use other characterization techniques (e.g. cross sectional TEM or low angle XRD) when we optimize the deposition conditions. In this paper, we deposited several Mo/Si multilayers and compared the structural factors extracted from various characterization techniques.