Effects of SiO2 and TiO2 Capping Layers on Sn Contamination Deposition Characteristics on the Surface of Extreme Ultraviolet Multilayer Coatings

The deposition characteristics of Sn contamination on the surface of extreme ultraviolet (EUV) multilayer coatings are closely related to the capping layer materials and properties. In this study, SiO2 and TiO2 single-layer coatings were prepared by plasma-enhanced atomic layer deposition. The effects of deposition temperature on the chemical composition, phase structure, surface morphology and density of the single-layer coatings were studied. SiO2 and TiO2 capping layers with different thicknesses were deposited on the surface of Mo2C/Si multilayer coatings at the optimized deposition temperature, and Ru capping layers were prepared on the surface of multilayers by magnetron sputtering deposition technology for comparative study. Sn contamination was deposited on the surface of multilayers with different capping layers by electron-beam evaporation. The results show that compared with the Ru capping layers, the TiO2 capping layers have better hydrophobic properties. SiO2 and TiO2 capping layers show better inhibition of Sn contamination crystallization, and have smaller surface coverage of Sn contamination.