SEMICONDUCTOR INTERCONNECT STRUCTURE WITH DOUBLE CONDUCTORS
Embodiments are directed to a semiconductor structure having a dual-layer interconnect and a barrier layer. The interconnect structure combines a first conductive layer, a second conductive layer, and a barrier layer disposed between. The result is a low via resistance combined with improved electromigration performance. In one embodiment, the first conductive layer is copper, the second conductive layer is cobalt, and the barrier layer is tantalum nitride. A barrier layer is not used in other embodiments. Other embodiments are also disclosed.
1 - 22 . canceled
23 . A method for forming a semiconductor interconnect comprising:
forming a trench in a substrate,
providing a metal line in the trench comprising a first conductive material,
wherein the metal line is elongated in a first direction parallel to the substrate,
removing a portion of the first conductive material to form a recess extending along the length of the metal line,
adding a second conductive material to the metal line by depositing the second conductive material in the recess substantially along the length of the metal line,
forming a via to the metal line, wherein the via extends in a second direction perpendicular to the substrate, and
wherein the second conductive material of the metal line comprises a direct interface with a conductive material of the via that constitutes the majority of the conductive material of the via.
24 . The method of claim 23 , further comprising:
forming a barrier layer between the first and second conductive materials.
25 . The method of claim 24 , wherein the barrier layer comprises tantalum.
26 . The method of claim 24 , wherein the barrier layer comprises tantalum nitride.
27 . The method of claim 24 , wherein the barrier layer comprises titanium nitride.
28 . The method of claim 23 , wherein the first and second conductive materials are the same.
29 . The method of claim 23 , wherein the first and second conductive materials comprise copper.
30 . The method of claim 23 , wherein the first and second conductive materials are different.
31 . The method of claim 23 , wherein the first conductive material comprises copper.
32 . The method of claim 23 , wherein the second conductive material comprises cobalt.
33 . The method of claim 23 , wherein the second conductive material comprises tungsten.
34 . The method of claim 23 , wherein the second conductive material comprises ruthenium.
35 . The method of claim 23 , wherein the second conductive material comprises aluminum.
36 . The method of claim 23 , wherein the second conductive material comprises molybdenum.
37 . The method of claim 23 , wherein the first conductive material comprises cobalt.
38 . The method of claim 23 , wherein the first conductive material comprises tungsten.
39 . The method of claim 23 , wherein the first conductive material comprises ruthenium.
40 . The method of claim 23 , wherein the first conductive material comprises aluminum.
41 . The method of claim 23 , wherein the first conductive material comprises molybdenum.
42 . The method of claim 23 , further comprising:
forming a first layer between the substrate and the metal line, wherein the first layer comprises cobalt.