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 mu m 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.