Highly-Reliable Low-Resistance Cu Interconnects with PVD-Ru/Ti Barrier Metal toward Automotive LSIs

Highly-reliable Cu interconnects with Ru/Ti barrier metal have been developed, in which Ti is diffused into the Ru-layer to establish a Cu-diffusion barrier. The PVD-Ru/Ti barrier metal with preferable crystal-orientation to Cu texture achieves the low line resistance. The Ti-doping in the Cu grain boundary just under the via improves the Cu-via reliabilities, besides keeping the Cu line resistance low. The Cu line with the Ru/Ti barrier metal is a strong candidate for automotive LSIs in future, requiring high performance and ultra-high reliability.