Method for forming capping barrier layer over copper feature

摘要

A method for forming a capping barrier layer over a metal filled semiconductor feature including providing a semiconductor process wafer including a metal filled feature lined with a first metal diffusion barrier layer; forming a recessed area over the upper portion of the metal filled feature with respect to a feature opening level including an adjacent dielectric layer; blanket depositing a second metal diffusion barrier layer over the recessed area; and, carrying out a chemical mechanical polishing (CMP) process to remove the second metal diffusion barrier layer above the feature opening level.