Low-k dielectric damage prevention

Abstract

The present disclosure describes a method for forming a nitrogen-rich protective layer within a low-k layer of a metallization layer to prevent damage to the low-k layer from subsequent processing operations. The method includes forming, on a substrate, a metallization layer having conductive structures in a low-k dielectric. The method further includes forming a capping layer on the conductive structures, where forming the capping layer includes exposing the metallization layer to a first plasma process to form a nitrogen-rich protective layer below a top surface of the low-k dielectric, releasing a precursor on the metallization layer to cover top surfaces of the conductive structures with precursor molecules, and treating the precursor molecules with a second plasma process to dissociate the precursor molecules and form the capping layer. Additionally, the method includes forming an etch stop layer to cover the capping layer and top surfaces of the low-k dielectric.