Investigation of direct replication techniques on periodic multilayers

Abstract

The direct replication of a periodic W/Si multilayer was investigated systematically. The W/Si multilayer was deposited by a high vacuum dc magnetron sputtering system. After deposition, the multilayer was transferred from the supersmooth mandrel onto a commercially available float glass substrate by the epoxy replication technique. The multilayer was characterized by the grazing incident x-ray reflectance (GIXR) measurement, atomic force microscope (AFM), and Zygo GPI interferometer before and after replication. The measured results showed that the multilayer structure and reflectivity were almost the same, and the surface roughness was 0.22 and 0.23 nm before and after replication, respectively. It was demonstrated that the W/Si multilayer was successfully replicated without modification of the structure, a significant increase of surface roughness, or apparent change of reflectivity. The optical figure of the substrate after replication experienced significant changes of many waves but was actually improved for this specific test. Future studies will focus on learning how to control the resulting optical figure of our replication process on a thin substrate. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).