Detailed study of electromigration induced damage in Al and AlCuSi interconnects

Abstract

Because of the continuing miniaturization, electromigration (EM) phenomena are still a key issue in reliability of VLSI metallizations. The present study of EM induced voiding and hillocking was performed on unpassivated conductor lines with various widths and current densities. Stressed and unstressed interconnects were carefully exymined with SEM and TEM techniques, espcially with regard to void densities, void sizes and characterisitic lengths between void and hillock. The fatal void shape was related to current density and line width indicating that the failure mechanism changes with decreasing line width and decreasing current density.