Advanced direct contact via (DCV) process with Ta/TaN/Ta tri-layer barrier for advanced BEOL dual damascene Cu interconnects

Three advanced direct contact via processes with Ta/TaN/Ta tri-layer barrier and the electromigration of their structures were comparatively investigated. The process of Ar
⁺
resputtering with median removal of tri-layer barrier shows the lowest defective die percentage. It also shows the highest activation energy and longest downstream electromigration lifetime.