Investigation of Stress Effect of Electromigration Behavior of Aluminum Strip

The unpassivated aluminum thin film test specimens and the four-point-bend equipment have been successfully fabricated and developed to investigate the thermal and external mechanical stress impacts during the electromigration (EM) test. This paper found that once the thin films reach equilibrium after the EM test, the aluminum atomic concentration, originally at 74%, decreases to about 60% at the cathode and increases up to about 80% at the anode. In addition, this paper observed that an incubation stage is present during the EM test. In this stage, no drift will take place. This result observed that the incubation stage in this paper is 2 h. Under the external mechanical stress range of -50 to +50 MPa, it was observed that the higher the tensile stress applied, the shorter the critical length becomes.