Strapped Cu interconnect for enhancing electromigration limit for power device application

Current can cause electromigration (EM) damage in power device interconnects, thus the current density should be properly controlled. Lowering the current density requires placing and routing wide interconnects, increasing the die size. Therefore, enhanced EM entitlement would help to reduce the die size. Towards this goal, we have investigated the impact of strapped Cu interconnects on EM performance. The experiments show that the strapped layer can have $\sim 5\mathrm{X}$ EM lifetime than the separated layers when the strapping VIA distance is comparable to or shorter than the Blech length. The strapping metal layer not only provides shunting benefit but also improves the layer’s diffusion property. The strapping technique is simple and does not request special process changes, and provides enhanced current carrying capability needed for the advanced power devices with low on-resistance.