Investigation of the effect of temperature and stress gradients on accelerated EM test for Cu narrow interconnects

Abstract

Electron wind force is considered to be the main driving force for the migration of metal atoms during electromigration (EM). Recent detail studies on the physics of EM reveal that the temperature gradient and mechanical stress gradient are also important factors to be considered. Atomistic EM models are developed using finite element analysis. The physical diffusion equations due to electron wind, temperature gradient and stress gradient are incorporated in the model. As atomic flux divergence (AFD) is the underlying mechanism for void nucleation and growth, the contributions due to electron wind, temperature gradient and stress gradient to the total atomic flux divergence are computed, and it is shown that other driving forces are comparable with the driving force arising from the electron wind.