Title :
Impact of oxygen on Cu surface for highly reliable low-k/Cu interconnects with CuSiN and Ti-based barrier metal
Author :
Hayashi, Y. ; Matsunaga, N. ; Wada, M. ; Nakao, S. ; Watanabe, K. ; Kato, S. ; Sakata, A. ; Kajita, A. ; Shibata, H.
Author_Institution :
Device Process Dev. Center, Toshiba Corp., Yokohama, Japan
Abstract :
A trade-off property of CuSiN between EM improvement and line resistance increase was resolved by a breakthrough that leaves oxygen at grain boundary of Cu line surface before CuSiN formation. Then, the combination of CuSiN and Ti-rich TiN (Ti(N)) barrier metal (-BM) was applied. Oxygen left by weakening process strength of CuOx reduction lowered line resistance, because Si diffusion causing line resistance increase was controlled by the oxygen at grain boundary. Low-damage process of CuOx reduction also improved voltage ramp dielectric breakdown (VRDB) property. Excellent EM performance brought about by CuSiN was kept by the combination with Ti(N)-BM, because the oxygen made Si and Ti distributions uniform at grain boundary of Cu surface by forming Ti-silicide. Cu atom transport that caused EM failure was suppressed throughout grain boundary of Cu surface.
Keywords :
copper compounds; electric breakdown; electromigration; low-k dielectric thin films; reliability; silicon compounds; titanium compounds; CuSiN; TiN; barrier metal; electromigration performance; line resistance; low-damage process; low-k interconnect reliability; voltage ramp dielectric breakdown; Breakdown voltage; Dielectric breakdown; Electrons; Grain boundaries; Large scale integration; Leakage current; Semiconductor device reliability; Surface resistance; Testing; Tin;
Conference_Titel :
Interconnect Technology Conference (IITC), 2010 International
Conference_Location :
Burlingame, CA
Print_ISBN :
978-1-4244-7676-3
DOI :
10.1109/IITC.2010.5510456
