The Formation of Ru/ZnO Multifunctional Bilayer through Area Selective Atomic Layer Deposition for Advanced Cu Metallization

We report the self-formation of multifunctional Ru/ZnO bilayer through area-selective atomic layer deposition (AS-ALD) for Cu interconnect technology. ALD-ZnO as a diffusion barrier and glue layer is selectively grown on SiO2 not on Cu using dodecanethiol (DDT) as an inhibitor. ALD-Ru as a liner and seed layer is grown on both ZnO and Cu surfaces using Ru metalorganic precursor, tricarbonyl(trimethylenemethane)-ruthenium [Ru(TMM)(CO)3]. The properties of Ru/ZnO bilayer are evaluated by diffusion barrier test and interfacial adhesion energy measurement of Cu/Ru/ZnO/Si multilayer. As a result, the formation of Cu silicides and the conductivity degradation do not occur with an increase in the annealing temperature up to 700 °C. The interfacial adhesion energy of Ru/SiO2 structure is measured using double cantilever beam test. Interfacial adhesion energy increases with ZnO (2 nm) between Ru and SiO2.