Exploration on electromigration short length effect of Low-K Cu interconnect

Short length effect on Electromigration (EM) of 40nm Low-k Cu interconnects was investigated through downstream structure and via chain. It is found that EM middle time-to-failure (MTTF) of short length metal can be enhanced at least 20 times. It is also observed that EM performance of short metal length degrades much slower, which can be applied to improve interconnect EM performance through via chain made of short length metal.