The interaction of metals and barrier layers with fluorinated silicon oxides

Fluorinated silicon oxide (FSG) films with varying fluorine (F) content wer e prepared by plasma-enhanced chemical vapor deposition (PECVD) using TEOS, O-2 and either C2F6 or NF3. Metal films (Al, Cu-1% Al, Cu) were deposited on the FSG either directly or with a barrier layer (Ta, TaN) between the me tal and the FSG. In addition, undoped PECVD SiO2 was studied as a capping l ayer on the FSG. Compositional depth profiles were obtained with both XPS a nd nuclear reaction analysis (NRA). F diffused rapidly through Ta, TaN and Al, and reacted with Al on the top surface. On the other hand, regardless o f barrier layers, Cu showed almost no reaction with F. F diffusion was also observed through PECVD SiO2. (C) 1999 Elsevier Science Ltd. All rights res erved.