Specimens which had been prepared by electron cyclotron nitridation were used as a diffusion barrier for Cu damascene interconnection. It was found that WSiN(6nm)/WSix(14nm) multi-layers effectively prevented Cu diffusion when the WSiN was formed by using radio-frequency biased application to the substrate. The radio-frequency power increased the N concentration of the WSiN and enhanced its amorphousness; thus leading to an improved barrier capability. The WSiN could form within the trench, and WSiN on the trench side-walls prevented Cu diffusion.

Copper Damascene Interconnection with Tungsten Silicon Nitride Diffusion Barrier Formed by Electron Cyclotron Resonance Plasma Nitridation. A.Hirata, K.Machida, N.Awaya, H.Kyuragi, M.Maeda: Japanese Journal of Applied Physics - 1, 1999, 38[4B], 2355-9