Methods of forming a high-k contact liner to improve effective via separation distance and the resulting devices

Abstract

A method includes forming first and second contact openings in a first dielectric layer. At least the first contact opening is at least partially lined with a liner layer. A first conductive feature is formed in the first contact opening and a second conductive feature is formed in the second contact opening. A portion of the liner layer adjacent a top surface of the first dielectric layer is removed to define a recess. A barrier layer is formed above the first dielectric layer and in the recess. The barrier layer has a first dielectric constant greater than a second dielectric constant of the first dielectric layer. A second dielectric layer is formed above the barrier layer. A third conductive feature is formed embedded in the second dielectric layer and contacting the second conductive feature.