Electrolytic Cobalt Fill of Sub-5 nm Node Interconnect Features

Electrolytic cobalt fill of sub-5 nm node features and a proposed model for the fill mechanism supported by cyclic voltammetry is presented. The transformation of the organic plating additive from an active to a de-activated state at the bottom of the feature is suggested as the mechanism of cobalt bottom-up fill. Plating results in features with 2- and - 4 nm pre-plate openings show void-free fill.