Analyzing electromigration near a right-angled corner composed of dissimilar metals by investigating the effect of material combination on atomic flux divergence

Atomic flux divergence (AFD) near a right-angled corner composed of dissimilar metals is theoretically analyzed in the present paper. A basic model of layered interconnect lines involving a right-angled corner is constructed. A two-dimensional electromigration (EM) problem near the corner is analyzed by treating the angled line as a single-crystal line without a passivation layer and with a uniform width. The material combination was found to play a significant role in determining the amount of AFD that occurs near the corner. The analysis of AFD in the present paper provides a unique insight into EM from the viewpoint of AFD singularities governed by the material combination. In addition, in terms of EM reliability issues in interconnects, several countermeasures for reducing the EM-induced damage are proposed.