Electrical and reliability characteristics of dielectric stack with low dielectric constant SiCOH and capping SiCNH films

This work investigates the electrical characteristics and reliability of a dielectric stack with a low-dielectric-constant (low-k) SiOCH film and a capping SiCNH film. Two kinds of low-k SiOCH films were used: a dense low-k film without porosity and a porous low-k film with a porosity of 15.0. The deposition of the capping SiCNH layer on both dense and porous low-k SiOCH films increased the overall dielectric constant. The porous low-k SiOCH film exhibited a greater increase in the dielectric constant. Capping a SiCNH layer on a low-k SiOCH film can retard damage by O2 plasma and diffusion of Cu ions diffusion. Lager improvements in time-dependent-dielectric-breakdown and electromigration lifetimes were detected for the porous low-k SiOCH film.