Failure Simulation of Angled Polycrystalline Lines Covered With Passivation Layer

Abstract

The atomic flux divergence due to electromigration in a passivated polycrystalline line, AFD*gen, has been formulated adding the effect of a passivation on electromigration damage to the governing parameter for electromigration damage in an unpassivated polycrystalline line, AFDgen. The parameter, AFD*gen, has been identified as a governing parameter for electromigration damage in the passivated polycrystalline line by experimental verification process. Recently, a prediction method for electromigration failure in the passivated polycrystalline line was proposed using AFD*gen, and the usefulness of the method was verified through experiment. Both the lifetime and the failure location in the passivated polycrystalline line can be predicted by means of numerical simulation of the failure process covering the building up of atomic density distribution, void initiation, void growth and ultimately—line failure. In this study, AFD*gen-based method for predicting electromigration failure is applied angled polycrystalline lines covered with passivation. There are few works on prediction of failure in the angled lines, though such lines are widely used in IC (integrated circuit) products. The failures are simulated when the corner position and its angle are changed. The dependency of lifetime and failure location on line shape is investigated.