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

• We reported a Cu-V alloy and a Cu-Mn alloy for the self-forming barrier.
• The Cu alloys exhibited superior thermal stability compared to pure Cu.
• SFB process is a suitable technique to form a conformal and reliable barrier layer.

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 μΩ-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.