Self-forming barrier characteristics of Cu-V and Cu-Mn films for Cu interconnects

We investigated the influence of annealing on the diffusion barrier property in a Mn-based and V-based barrier layer. The samples were annealed at various temperatures for 1 h in vacuum. X-ray diffraction revealed Cu (111), Cu (200) and Cu (220) peaks for the Cu-Mn and Cu-V alloys. Transmission electron microscopy showed that a 4-7 nm V-based interlayer self-formed and a 2-5 nm Mn-based interlayer self-formed at the interface after annealing. The resistivity of the annealed Cu-V alloy was reduced to 8.1 mu Omega-cm, which is greater than the resistivity of the annealed Cu-Mn alloy. The Mn-based interlayer and V-based interlayer showed excellent thermal stability. The results show that Mn and V based Cu alloys are suitable seed layer materials for Cu interconnects. (C) 2013 Elsevier B. V. All rights reserved