New Microstructure-Related EM Degradation and Failure Mechanisms in Cu Interconnects with CoWP Coating.

In-situ SEM electromigration studies were performed at fully embedded via/line interconnect structures to visualize the time-dependent void evolution in inlaid copper interconnects with additional CoWP coating. Void formation, growth and movement, and consequently interconnect degradation are changed compared to the process of record. The degradation dynamics depends on both, interface bonding and copper microstructure. The increased bonding strength of the top interface of the copper interconnect line reduces the electromigration-induced mass transport along the interfaces significantly. As a consequence, grain boundary diffusion and liner interface diffusion becomes increasingly important for electromigration-induced degradation processes. [ABSTRACT FROM AUTHOR]