PEALD Ru liner conformality and Cu trench fill characteristics

Abstract

Conformality studies on trench structures in oxide and porous lowk dielectrics as well as Cu trench fill evaluations have been conducted employing a plasma enhanced atomic layer deposition (PEALD) Ru liner process in conjunction with conventional physical vapor deposited (PVD) Ta(N). The conformal growth of Ru by PEALD was demonstrated, while the benefits of a Ru layer underneath a conventional PVD Cu seed layer for Cu trench fill enhancement were shown. Poor PVD Cu seed layer coverage is considered to be the prime cause of the poor Cu/liner interface quality observed in the case of conventional Ta(N)/Cu liner/seed processes. Detailed EELS/EDX analysis has confirmed the presence of TaOx at the Ta(N)/Cu interface which is anticipated to be a key contributing factor impacting reliability performance. © The Electrochemical Society.