Influence of convective air-cooling on hydrostatic stress induced atomic migration characteristics of a thin Cu-line with Cu-Sn IMC under a DC field

Abstract

Abstract The present paper addresses the influential effect of convective air cooling on the stress-migration induced atomic flux divergence in a copper interconnect/line with copper-tin intermetallic compound under a DC field of high current density. Three identical thin copper lines, namely, a pure Cu line, a copper line with Cu-Sn intermetallic and a line with lead-free solder-joint are considered as the basis for conducting the present investigation of current-induced atomic migration. The associated two-dimensional fields of electric potential, temperature, thermal stress as well as atomic distributions are obtained by solving the relevant coupled multi-physics problems using computer-based numerical schemes. Finally, the stressmigration induced atomic-flux divergence characteristics of three Cu lines are compared with those of electromigration as a function of cooling air velocity under natural and forced convection to quantify the relative contribution of stress migration in the perspective of overall atomic diffusion.