Amorphous Ru / Polycrystalline Ru Highly Reliable Stacked Layer Barrier Technology

Abstract

An amorphous Ru (a-Ru) underneath polycrystalline Ru (p-Ru) stacked barrier structure (a-Ru/p-Ru) is proposed as a highly reliable barrier metal technology. The a-Ru with less grain boundary contacted to a dielectric layer showed higher barrier property than a conventional TaN/Ta or the p-Ru barrier, and the p-Ru layer with high adhesion to Cu material contacted to Cu interconnect showed three orders magnitude longer electro-migration life time than the TaN/Ta barrier.