Electromigration Damage and Failure Distributions in Al-4wt.%Cu Interconnects

Abstract

AbstractUnpassivated 2.1μm and 1.1μm wide lines of Al-4wt.%Cu have been electromigration-stressed to failure under accelerated testing conditions (up to 300 °C and 2 x 1010 A m-2). The line resistance and microstructure and the development of electromigration damage are discontinuously recorded. Distributions of damage sites (hillocks and voids) along the line lengths are measured, and the evolution of the distributions with stressing time is followed. The distances between damage sites show a clear correlation with the grain structure. Damage and failure sites are concentrated near the end of the lines at which electrons enter.