Effective Cu Surface Pre-treatment for High-reliable 22nm-node Cu Dual Damascene Interconnects with High Plasma resistant Ultra Low-k Dielectric (k=2.2)

摘要

The process damage of low-k films is one of the most serious concerns to improve the RC performance and reliability. The low-k damage repair [1] and damage layer elimination [2] processes are promising ways to suppress the capacitance increase by the side-wall and trench bottom damages induced by the plasma processes. However, it is difficult to modify the surface low-k damages after Cu surface pre-treatment, because the clean Cu surface adjacent to low-k surface needs to be maintained throughout until cap deposition (fig. 1).