Optical performance, structure and thermal stability of Al/Zr multilayers working at above 17nm

We report on further development of the optical, structural performances and temporal stability of Al(1%wtSi)/Zr multilayers. The multilayers with variable periods (from 10 to 80) are fitted by four-layer model. Below 40 periods, the surface and interfacial roughnesses are increased with the period numbers, but not decrease the reflectivity of Al(1%wtSi)/Zr multilayers. Above 40 periods, such as 80 periods, the reflectivity is down to 34.7% due to larger roughness and worse interfacial boundary To improve the reflectivity, we modify some parameters during deposition process. The results in the EUV reflectivity show that the reflectivity of the sample with 40 periods is increased from 41.2% to 48.2%. The temporal stability of Al(1%wtSi)/Zr samples with different annealing temperatures has been observed over 35 days.