Investigation of Barrier Property of Copper Manganese Alloy on Ruthenium

This paper investigates the properties of CuMn/Ru/SiO₂. The optimal concentration of Mn in the CuMn alloy as a barrier layer in this structure is determined. The properties of CuMn/Ru/SiO₂ are compared to those of CuMn/SiO₂ and CuMn/Ta/SiO₂. The electrical and material properties of CuMn (0-10 at.% Mn) alloy films deposited on SiO₂, Ta, and Ru are studied. A diffusion barrier layer self-formed at the interface during annealing, and the growth behavior followed a logarithmic rate law. The microstructures of the CuMn films are analyzed using trans mission electron microscopy and are correlated with the electrical properties. After thermal treatment, only Cu-5 at.% Mn/SiO₂ did not exhibit a diffusion of Cu atoms. After annealing, the thermal stability of films grown on Ru/SiO₂ was better than that of films grown on SiO₂ and Ta/SiO₂. When a Ta or Ru layer was added, the Mn atoms diffused not only to the interface but also to the grain boundaries in the under layer and to the interface between the under layer and SiO₂. The tolerance of Mn content increased when the Ru layer was used, and thus, CuMn/Ru prevented the diffusion of Cu after heat treatment at 600 °C for 30 min.