Hydrogen Diffusion Between Plasma-Deposited Silicon Nitridepolyimide Polymer Interfaces

Abstract

A Nuclear Reaction Analysis (NRA) for Hydrogen technique was used to analyze the hydrogen concentration near Plasma Enchanced Chemical Vapor Deposition (PECVD) silicon nitride-polyimide interfaces at various nitride-deposition and polyimide-polymer-curing temperatures. The CF 4 + 02 (8% 02) plasma-etch-rate variation of PECVD silicon nitride films deposited on polyimide appeared to correlate well with the variation of hydrogen-depth profiles in the nitride films. The NRA data indicate that hydrogen-depth-profile fluctuation in the nitride films is due to hydrogen diffusion between the nitride-polyimide interfaces during deposition. Annealing treatment of polyimide films in a hydrogen atmosphere prior to the nitride film deposition tends to enhance the hydrogen-depth-profile uniformity in the nitride films, and thus substantially reduces or eliminates variation in the nitride plasma-etch rate.