Coupled Mechanical/Electrical Failure In Thin Film Interconnects Under Electromigration

Electromigration induced failures in thin film interconnects, as a persistent concern of the semiconductor industry, is a dominant factor which influences the life time and the reliability of semiconductor integration circuits. With the technical development of the semiconductor industry, the electromigration becomes more and more important. This thesis studies the electromigration induced failures in thin film interconnects, from theoretical, numerical and experimental aspects. In the theoretical studies, attention is focused on the void and crack nucleation mechanism induced by coupled electromigration and stress-migration in an isolated interface;and also on the damage and morphological evolution induced by surface migration. The numerical simulation investigates the void behaviors under electromigration in single crystals, and many new instability configurations of void are simulated. In the in-situ electromigration experiments, the damage evolution processes of the aluminum thin film interconnects, which have a submicron columnar poly-crystalline micro-structure, are observed in detail. The damage mechanism of forming hillock-like long protrusions is analyzed.