DIAMOND AS A POLISH-STOP LAYER FOR CHEMICAL-MECHANICAL PLANARIZATION IN A DAMASCENE PROCESS FLOW

摘要

A method of using diamond or a diamond-like carbon layer as a polish-stop for patterning a metal level into an inter-level dielectric substrate using a damascene process flow. The diamond or diamond-like carbon layer is deposited onto the surface of the substrate before patterning the metal level. A protective layer is then deposited over the diamond or diamond-like carbon polish-stop layer, wherein such protective layer may act as an additional polish-stop layer. Together, the diamond or diamond-like carbon polish-stop layer and the protective layer are used as a hard-mask for patterning the trenches that will become the metal features, wherein such protective layer protects the diamond or diamond-like carbon polish-stop layer during the patterning process. After deposition of a conductive metal layer, the dielectric substrate is polished to remove excess conductive material, as well as topography. In the polishing process, the diamond or diamond-like carbon polish-stop layer and any remaining protective layer are used as polish-stop layers. The diamond or diamond-like carbon polish-stop layer allows for an improved planar surface, thereby resulting in an sufficient decrease in topography at the surface of the inter-level dielectric.