The addition of aluminium and manganese to ruthenium liner layers for use as a copper diffusion barrier

The chemical interaction of Al and Mn deposited on Ru thin films for use as copper diffusion barrier layers are assessed in-situ using x-ray photoelectron spectroscopy (XPS). Thin (~1-2 nm) Al and Mn films were separately deposited on 3 nm Ru liner layers on SiO₂, and both Al/Ru/SiO₂ and Mn/Ru/SiO₂ structures were subsequently thermally annealed. Results indicate the diffusion of both metals through the Ru thin films and the subsequent chemical interaction with the underlying SiO₂ substrate to form Al₂O₃ and MnSiO₃. In both cases, the reduction of SiO₂ leads to the release of Si from the dielectric and the upward diffusion of Si into the Ru liner layers.