Strain-induced anisotropy of electromigration in copper interconnect

Modern interconnect represents a complex mechanical system where stress sources determined by the fabrication process influence electromigration. Due to geometry and material composition of a typical interconnect this stress is non-hydrostatic and causes a general anisotropy of material transport. The electromigration model used in this work incorporates all important driving forces for atom migration coupled with the solution of the electrical and thermal problems. Our approach differs from others by considering a diffusivity tensor in the transport equation taking into account the diffusion anisotropy generated by the applied strains.