Dynamics of electromigration induced void in submicron Cu interconnects

A combined driving force model consisting of three driving forces is implemented for copper dual damascene line-via interconnects using finite element method. Good agreement is found between the experimental and computational results on the void volume at failure and time varying resistance change during electromigration stressing. The void evolution is also computed showing the process of the void growth that lead to the void observed at failure, and it is found that the void grows at the inner corner between the metallization and the via initially. The model predicts that, the driving force from the stress gradient dominates at the very beginning of the mass transport while in the latter stage, the electron-wind force dominates.