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 (similar to 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.