Formulas for the driving force of electromigration were presented using concepts of the tension density, the external force density, and the effective charge tensor density. The “dynamic” wind charge tensor density, Zdw(r), was revealed over and above the conventional “static” wind charge tensor density, Zsw(r). The application of the concepts to the electromigration reliability problems of ultra large-scale integration devices where extremely high current densities should be maintained through ultra-thin film interconnects was demonstrated. Quantum mechanical wave-packet propagation of an Al atom was examined in some models of thin Al lines which contained atomic defects, using the first-principle electronic structure calculations under the periodic boundary condition. The dynamic electronic properties revealed by the simulation demonstrated the characteristic features of Zdw(r) in the course of Al electromigration in the bulk, surface and grain boundary.

First Principles Dynamic Electronic Characteristics of Al Electromigration in the Bulk, Surface and Grain Boundary. K.Doi, K.Iguchi, K.Nakamura, A.Tachibana: Physical Review B, 2003, 67[11], 115124 (14pp)