On stress evolution and interaction during electromigration in near bamboo structure lines

Abstract

Electromigration-induced stress in near bamboo structure interconnects has been simulated by the finite element method. The maximum stress at the juncture of polygranular clusters and bamboo segments increases when the stress profile interacts with the line end. The maximum stress at final steady state depends on the relative location of the polygranular cluster in the line under the constant source boundary condition. Under the blocking boundary condition, the steady state stress profile (if it exists) is determined only by current density and total line length and is independent of the microstructure of the line. Finally, the ratio of effective diffusivity of the cluster to that of bamboo segments affects the magnitude of maximum stress at quasi-steady state.