Abstract: A process for forming a tungsten plug structure, in a narrow diameter contact hole, has been developed. The process features the use of a composite layer, comprised on an underlying titanium layer, and an overlying, first titanium nitride barrier layer, on the walls, and at the bottom, of the narrow diameter contact hole. After an RTA procedure, used to create a titanium silicide layer, at the bottom of the narrow diameter contact hole, a second titanium nitride layer is deposited, to fill possible defects in the underlying first titanium nitride, that may have been created during the RTA procedure. The tungsten plug structure is then formed, embedded by dual titanium nitride barrier layers.

Abstract: A method for fabricating local interconnect metal structures, overlying metal filled via hole openings, has been developed. This invention features the creation of an aluminum based interconnect structure, comprised with an underlying titanium nitride layer. The titanium nitride layer overlays a metal filled via hole, during a photolithographic exposure that is used for formation of the photoresist shapes that are needed for local interconnect metal structure patterning. The anti-reflective properties of the titanium nitride layer allow the formation of the resulting photoresist shapes to be defined without interfering reflections from the underlying metal plug.