Selectively Formed Metal Organic Chemical Vapor Deposition TiSiN and Ta Barrier Metal Using Direct Contact Via Process for Sub-65 nm Interconnects

Abstract

We report integration of metal organic chemical vapor deposition (MOCVD) TiSiN barrier metal into 65 nm low-k dielectric (k=2.9) interconnects. Selective TiSiN barrier was formed along via trench wall using direct contact via (DCV) process and subsequent Ta incorporation into Cu was found to significantly improve electromigration (EM) reliability. Also, a large reduction of 0.1 µm via/line resistances is achieved. The proposed integration method allows MOCVD TiSiN usable as a barrier metal for the nano scale interconnects, taking advantages of high throughput and excellent step coverage of MOCVD process compared to other barrier processes.