Diffusion barrier properties of very thin TaN with high nitrogen concentration

The magnetron sputter deposition barrier properties of thin TaN with high nitrogen concentration for copper interconnect systems were analyzed. The TaN thickness at each composition and nitrogen flow was determined by cross-sectional transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The diffusion barrier failure temperature was a strong function of nitrogen concentration in the TaN. The results show that the conventional grain boundary diffusion was dominated by the interfacial contribution to diffusion barrier effectiveness.