Copper contact metallization using Ru-based barrier liners for 45 nm and 32 nm nodes: Reliability and device performance

Abstract

This work presents Cu contact metallization results using CVD Ru-containing liners for 45 and 32 nm nodes. CVD Ru-containing liner stacks utilized a non-halogen deposition process. CVD Ru-containing liners exhibited very good gap fill performance compared to PVD-based Ta liners. We selected CVD Ru-containing liners that passed barrier breakdown test and Cu diffusion test with 400°C 2 hours anneal. The selected CVD-Ru containing liners were then tested on fully integrated 45 nm and 32 nm node devices. Contact resistance of Cu using CVD Ru liners showed about one-third and one-fourth of W contact resistance for 45 nm and 32 nm nodes, respectively. No yield degradation was observed in 7.5-million contact chain current for 45 nm node and 100-thousand contact chain current for 32 nm node when BEOL thermal anneal was applied. The gate dielectric voltage breakdown test of Cu contact was comparable to that of W contact. Electromigration of Cu contact was also comparable to that of W contact. There was about 20% improvement in drive current with Cu contact metallization for 32 nm node device. © 2009 Materials Research Society.