A rigorous reformulation of internal entropy production and the rate of entropy flow was developed for multi-component systems consisting of heterophases, interfaces and/or surfaces. The result was a well-posed moving boundary value problem which described the dynamics of curved interfaces and the surfaces associated with voids and/or cracks that were intersected by grain boundaries. Extensive computer simulations were made of void configuration evolution during intergranular motion. In particular, the evolution resulting from the action of capillary and electromigration forces in thin-film metallic interconnects having a bamboo structure was simulated; characterized by grain boundaries were aligned perpendicular to the free surface of the metallic film interconnects. An analysis of experimental data, using previously derived mean-time-to-failure formulae gave consistent values of interface diffusion coefficients and enthalpies of voids. A value of 3.0 x 10−6exp[−0.62(eV)/kT]m2/s found was for voids that formed in the interior of Al interconnects without surface contamination. A value of 6.5 x 10−6exp[−0.84(eV)/kT]m2/s was found for those that nucleated at triple junctions or at

grain-boundary/surface intersections, where the chemical impurities could act as trapping centers for hopping vacancies.

Irreversible Thermodynamics of Triple Junctions during the Intergranular Void Motion under the Electromigration Forces. T.O.Ogurtani, E.E.Oren: International Journal of Solids and Structures, 2005, 42[13], 3918-52