Conductive Interconnect Structures in Integrated Circuits

An interconnect structure and a method of forming the interconnect structure are provided. A dielectric layer and openings therein are formed over a substrate. A conductive seed layer is formed over the top surface and along a bottom and sidewalls of the openings. A conductive fill layer is formed over the seed layer. Metal oxide on the surface of the seed layer may be reduced/removed by a surface pre-treatment. The cleaned surface is covered by depositing fill material over the seed layer without exposing the surface to oxygen. The surface treatment may include a reactive remote plasma clean using hydrogen radicals. If electroplating is used to deposit the fill layer, then the surface treatment may include soaking the substrate in the electrolyte before turning on the electroplating current. Other surface treatments may include active pre-clean (APC) using hydrogen radicals; or Ar sputtering using a metal clean version xT (MCxT) tool.