Comparison of Cu electromigration lifetime in Cu interconnects coated with various caps

The investigation of electromigration in Cu Damascene with bamboo-like grain structures, either capped with Ta/TaN, SiNx, SiC xNyHz, or without any cap, was presented. The Cu diffusion was reduced in the samples with SiNx or SiC xHyNz caps, at the top of Cu Damascene. For samples with a Ta/TaN cap, a remarkable improvement of Cu electromigration lifetime was observed.