A process of forming a thin, protective insulator layer, on the sides of metal interconnect structures, prior to the deposition of a halogen containing, low k dielectric layer, has been developed. The process features the growth of a thin metal nitride, or thin metal oxide layer, on the exposed sides of the metal interconnect structures, via a plasma treatment, performed in either a nitrogen containing, or in a water containing, ambient. The thin layer protects the metal interconnect structure from the corrosive, as well as delamination effects, created by the halogen, or halogen products, contained in overlying low k dielectric layers, such as fluorinated silica glass.