Effect of tungsten chemical vapor deposition nucleation step on via performance

✍ Scribed by L. Ulmer; L. Georges; J.C. Veler; Y. Morand; M. Bakli; V. Ferrier; M. Lerme; L. Perroud; T. Morel

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 356 KB
• Volume: 33
• Category: Article
• ISSN: 0167-9317
• DOI: 10.1016/s0167-9317(96)00037-8

✦ Synopsis

This paper presents a study of the nucleation process for W Chemical Vapor Deposition (CVD). The nucleation layer was obtained by reduction of WF 6 by Sill 4 and H 2. This double reduction had proved to have a large latitude regarding fluorine attack of the Ti/TiN glue layer. High WE 6 flOWS could then be investigated and process parameters controlling the step coverage were determined. Electrical performance within a 0.25 Ixm CMOS interconnects scheme using a collimated PVD glue layer was investigated. The W nucleation layer proved to constitute a barrier layer against fluorine diffusion at the bottom of vias during via fill processing. Thus, a high step coverage W nucleation process extends the TiN barrier efficiency to a higher via aspect ratio.