SiCN and Ta/TaN barriers for Cu/Ultra low k integration in 0.13 μm technology

摘要

Single damascene Cu lines using bi-layer Ta/TaN barrier with and without SiCN and plasma treatment for Cu-ultra low-k interconnect in 0.13 μm technology have been investigated. It was found that the N_2/H_2 plasma treatment on the ULK surface before depositing barrier and Cu could reduce the line resistance significantly, but it also brought more surface defects on the sidewall and larger diffusion length. Compared with only Ta/TaN barrier layer structure, introduction of an additional SiCN layer could significantly improve the breakdown voltage, line to line leakage and thermal stability. This is because the thin SiCN layer not only effectively blocks diffusion of elements on both sides, but also significantly improves the mechanical property of the ultra low-k polymer.