Modeling of electromigration of the through silicon via interconnects

Abstract

A finite element model which includes electromigration, thermomigration, stress migration and concentration diffusion is established to study the mass diffusion phenomenon. Numerical experiment is carried out to obtain the electrical, thermal, stress and atomic concentration fields of the sweat and through silicon via (TSV) structure under high current density load. The effectiveness of the electromigration FEM model is confirmed by the simulation of the sweat structure. The results from the simulation are consistent with the observation of the experiment conducted by Dallleau, D. et al. The current crowding, temperature distribution, von Mises and hydrostatic stress distribution and atomic concentration fields of the TSV structure is obtained from the numerical calculation. The current crowding occurs at the corner of the copper pad. The maximum compressive hydrostatic stress happens in the center of the copper via and the center of copper pads are under tensile hydrostatic stress which has important role in the migration of copper atoms. The probable location where the void and hillock may be generated is identified through the atomic distribution after 10000-second electromigration simulation. The migration failure mechanism which is critical for design and application of TSV technology in the 3D package is investigated.