Microscopic small solder joints were part of most microelectronic packages. They show a variety of micro-morphological changes such as decomposition into phases and phase coarsening. In order to analyze the evolution of the alloy by means of a diffusion theory of heterogeneous solid mixtures an extended Cahn-Hilliard phase-field model was applied. The Cahn-Hilliard equation involved a bipotential operator and, accordingly, fourth-order spatial derivatives. The diffusion equation was here discretized spatially by means of rational B-spline finite element basis functions. To illustrate the versatility of this approach numerical simulations of phase decomposition and coarsening controlled by diffusion and by mechanical loading were discussed and compared with experimental results.

Numerical Investigation of Diffusion Induced Coarsening Processes in Binary Alloys. D.Anders, K.Weinberg: IOP Conference Series - Materials Science and Engineering, 2010, 10[1], 012100