Electrical properties and reliability of ALD TaN barrier for sub-90nmPitch Cu interconnects

Abstract

• Nodes with ≤90nmP finer Cu ICs offers adoption of alternative and extendible ALD TaN barrier layers to replace the conventional PVD. • Obviously, the primary benefits for Cu IC Trenches/Vias are: - high conformality; hence, thinner thicknesses and low overhang vs. PVD - significantly decreased Via contact R at uncompromised Reliability; ∼PVD - evtl. lower Line Res especially in ≤64nmP nodes due to a better gapfill. • However, more consistent effects, such as PVD vs. ALD differences in TaNx nucleation on various surfaces, final film phase, μ-structure of barrier / liner & quality and interfacial composition between each of the multilayer components have to be considered. • Observations from this study are intensively being utilized in further ALD barrier development for the Cu ICs metallization in ≤64nmPitch nodes to enhance margins for gapfill and the overall performance.