Selective Silicidation of Co Using Silane or Disilane for Anti-Oxidation Barrier Layer in Cu Metallization

• Published in: Japanese Journal of Applied Physics Vol. 43; no. 9R; p. 6001
• Main Authors: Noda, Suguru, Hirai, Rika, Komiyama, Hiroshi, Shimogaki, Yukihiro
• Format: Journal Article
• Language: English
• Published: 01.09.2004
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.43.6001

Aiming to realize a conductive passivation layer for copper interconnection, the solid-gas reactions of cobalt films with silane and with disilane to form cobalt silicides are experimentally investigated. X-ray photoelectron spectroscopy revealed that cobalt silicides layers of up to 6 nm thickness can be selectively formed in the reaction at 473–673 K within 5 min without detectable silicon deposition on silicon dioxide, a common inter-metal dielectric layer. Rapid thermal oxidation experiments revealed that the silicided cobalt layers had better anti-oxidation performance than untreated cobalt layers, and the effect of silicidation was to suppress copper out-diffusion through the cobalt layers. Because cobalt-based alloys can be selectively electroless-plated on copper, selective silicidation of cobalt layers will be easily incorporated into device processing.