Improving lifetime of Cu interconnects with adding compressive stress at cathode end

We show that Cu interconnect lifetime is increased, at least by a factor of 2, with an electromigration (EM) pre-stress. Stress modeling shows that EM induced void at one line end creates compressive stress at the other end. High compressive stress induces an incubation time before EM starts. Incubation time is proportional to the amount of compressive stress induced.