Method for the formation of interconnects and landing pads having a thin, conductive film underlying the plug or an associated contact of via hole

摘要

The present invention provides a method for the formation of interconnects and landing pads having a thin, conductive film underlying the plug of an associated contact or via hole. In accordance with the preferred embodiment of the present invention, a silicon substrate is provided having at least one device region formed at the surface of the substrate. An insulating layer is deposited over the substrate having at least one contact hole formed through the insulating layer to expose the device region. A first blanket layer of titanium is deposited as a tungsten adhesion layer over the insulating layer and the exposed device region within the contact hole. A second blanket layer of titanium-tungsten or titanium-nitride is then deposited as a tungsten barrier layer over the adhesion layer. Subsequently, a blanket contact plug layer comprising tungsten is deposited over the barrier layer by chemical vapor deposition. Both the contact plug layer and the barrier layer are then removed from the surface of the adhesion layer everywhere except within the contact hole by a selective etch back process wherein a selectivity between tungsten and titanium of at least 5:1 is achieved. Next, the exposed portions of the adhesion layer are patterned with a mask and etched to remove those portions of the adhesion layer not covered by the mask, thus converting the adhesion layer into a thin film interconnect or landing pad underlying the contact plug of the associated contact hole.