Methods for forming interconnect structures by co-plating of noble metals and structures formed thereby

Abstract

A method of forming a copper interconnect, comprising forming an opening in a dielectric layer disposed on a substrate, forming a barrier layer over the opening, forming a seed layer over the metal layer, and forming a copper-noble metal alloy layer by electroplating and/or electroless deposition on the seed layer. The copper-noble metal alloy improves the electrical characteristics and reliability of the copper interconnect.

1 - 23 . (canceled)  
   
   
       24 . A copper interconnect, comprising: 
 a dielectric layer having an opening;    a barrier layer on the opening; and    a copper alloy layer on the barrier layer wherein the copper alloy layer substantially comprises copper and a noble metal.    
   
   
       25 . The method of  claim 24  wherein the noble metal comprises less than about 4% of the atomic weight of the copper alloy layer.  
   
   
       26 . The copper interconnect of  claim 25 , further including forming a cladding layer on the copper alloy layer.  
   
   
       27 . The copper interconnect of  claim 26  wherein the cladding layer substantially comprises a material selected from the group consisting of silver, palladium, platinum, rhodium, ruthenium, gold, iridium, osmium, tungsten and combinations thereof.  
   
   
       28 . The copper interconnect of  claim 24 , further including forming an etch stop layer on the copper alloy layer.  
   
   
       29 . The copper interconnect of  claim 28  wherein the etch stop layer substantially comprises a material selected from the group consisting of silicon carbide, silicon nitride, and combinations thereof.