Semiconductor device and methods of formation

Abstract

A dielectric layer of a semiconductor device may be treated using an oxidation treatment process to tune the dielectric constant of the dielectric layer. For example, an etch stop layer (ESL) in an interconnect layer of the semiconductor device may be formed of a high dielectric constant (high-k) dielectric material, which provides etch selectivity for the ESL relative to other dielectric layers in the interconnect layer. A recess may be formed through the ESL and through the dielectric layers, and a conductive structure may be formed in the recess. Prior to formation of the conductive structure, an oxidation treatment operation may be performed to oxidize the exposed ends of the ESL in the recess. The oxidation treatment may lower the dielectric constant of the ends of the ESL, which may result in the ends of the ESL being less susceptible to current leakage through tunneling, hot-carrier injection, and／or thermionic emission.