Effect of strains on anisotropic material transport in copper interconnect structures under electromigration stress

摘要

We analyzed the effect of strains on material transport in a typical dual damascene copper interconnect via under electromigration stress. The electromigration model 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. We have obtained off-diagonal components of the diffusivity tensor up to 30% of the diagonal ones and a different distribution of vacancies due to electromigration.