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Proceedings Paper

Control of the interaction of metals with fluorinated silicon oxides
Author(s): Sara E. Kim; Christoph O. Steinbruchel; Atul Kumar; H. Bakhru
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Paper Abstract

Metal films (Al, Cu-1%Al, Cu) were deposited on fluorinated silicon oxide (FSG) of varying fluorine (F) content, obtained from plasma-enhanced chemical vapor deposition, either directly or with a barrier layer (Ta, TaN, TiN) in between. Compositional analysis was done with FTIR and nuclear reaction analysis (NRA), and depth profiles were performed with XPS and NRA. The dielectric constant of the FSG films is shown to be a combined function of film density and F content. This points to structural differences between FSG and undoped SiO2 films. For Al and Cu-1%Al on FSG, rapid diffusion of F atoms through the metal occurs at typical annealing conditions. With Al, the diffused F accumulates on the top metal surface, and practically no F is present in the bulk of the film. With Cu- 1%Al, surface accumulation and an appreciable bulk concentration of F are observed. With Cu, no significant F diffusion was detectable. Neither Ta nor TaN are good barriers against F diffusion into the metals. On the other hand, TiN may be a useful barrier, as it shows no significant F diffusion but some reaction with F at the Al/TiN interface. A suitable plasma treatment of the FSG before metal deposition can inhibit substantially F diffusion.

Paper Details

Date Published: 4 September 1998
PDF: 6 pages
Proc. SPIE 3508, Multilevel Interconnect Technology II, (4 September 1998); doi: 10.1117/12.324045
Show Author Affiliations
Sara E. Kim, Rensselaer Polytechnic Institute (United States)
Christoph O. Steinbruchel, Rensselaer Polytechnic Institute (United States)
Atul Kumar, SUNY/Albany (United States)
H. Bakhru, SUNY/Albany (United States)

Published in SPIE Proceedings Vol. 3508:
Multilevel Interconnect Technology II
Mart Graef; Divyesh N. Patel, Editor(s)

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