It was noted that, in interfacial reactions, short-circuit diffusion along grain boundaries or interfaces could be accompanied by intermetallic compound formation. Fisher's grain-boundary diffusion model was modified here so as to include this reactive kinetic process. An analytical solution was obtained which yielded a t¼ dependence of the penetration, as in Fisher's model. The important kinetic parameters in the calculation were the diffusion coefficient along the short-circuit path, the intrinsic interdiffusion coefficient in the compound, and the partition coefficient. A comparison was made between predicted and measured data on the lateral penetration of eutectic Sn-Pb solder along the interface between electroless Ni and SiON dielectric; accompanied by Sn4Ni3 compound formation.

Kinetic Analysis of Interfacial Diffusion Accompanied by Intermetallic Compound Formation. P.G.Kim, J.W.Jang, K.N.Tu, D.R.Frear: Journal of Applied Physics, 1999, 86[3], 1266-72