Integration scheme for non-feature-size dependent cu-alloy introduction

摘要

In the present method of fabricating a semiconductor device, openings of different configurations (for example, different aspect ratios) are provided in a dielectric layer. Substantially undoped copper is deposited over the dielectric layer, filling the openings and extending above the dielectric layer, the different configurations of the openings providing an upper surface of the substantially undoped copper that is generally non-planar. A portion of the substantially undoped copper is removed to provide a substantially planar upper surface thereof, and a layer of doped copper is deposited on the upper surface of the substantially undoped copper. An anneal step is undertaken to difffuse the doping element into the copper in the openings.