Effect of interface strength on electromigration-induced inlaid copper interconnect degradation: Experiment and simulation

Abstract Both in situ microscopy experiments at embedded inlaid copper interconnect structures and numerical simulations based on a physical model provide information about electromigration-induced degradation mechanisms in on-chip interconnects. It is shown that the modification of the bonding strength of the weakest interface results in completely changed degradation and failure mechanisms. Transmission electron microscopy (TEM) images of standard Cu/SiNx interfaces are compared with strengthened interfaces, e. g., after applying an additional metal coating or a self-assembled monolayer (SAM) on top of the polished copper lines. The changed degradation mechanisms as observed with the in situ scanning electron microscopy (SEM) experiment and as predicted based on the numerical simulations are explained based on TEM images.