A. Hirata et al., Copper damascene interconnection with tungsten silicon nitride diffusion barrier formed by electron cyclotron resonance plasma nitridation, JPN J A P 1, 38(4B), 1999, pp. 2355-2359
This paper describes the application of tungsten silicon nitride (WSiN) for
med by electron cyclotron nitridation (ECR) plasma nitridation as a diffusi
on barrier for copper (Cu) damascene interconnection. WSiN(6 nm)/WSix(14 nm
) multi-layer prevents Cu diffusion well when WSiN is formed with RF bias a
pplication to the substrate. The RF power increases the nitrogen concentrat
ion of the WSiN and enhances its amorphousness, which lead to the improved
barrier capability. WSiN can be formed inside the trench, and the WSiN on t
he trench side walls prevents Cu diffusion. The use of this extremely thin
barrier metal suppresses the increase of interconnection resistivity.