Doping of copper wiring structures in back end of line processing

Abstract

A method of forming a metal interconnect structure includes forming a copper line within an interlevel dielectric (ILD) layer; directly doping a top surface of the copper line with a copper alloy material; and forming a dielectric layer over the ILD layer and the copper alloy material; wherein the copper alloy material serves an adhesion interface layer between the copper line and the dielectric layer.

What is claimed is: 
     
         1 . A metal interconnect structure, comprising:
 a copper line formed within an interlevel dielectric (ILD) layer;   a barrier layer surrounding bottom and sidewall surfaces of the copper line, with a sidewall of the copper line having a sidewall copper alloy concentration;   a top surface of the copper line directly doped with a copper alloy material, the top surface of the copper line having a top copper alloy concentration;   wherein the top copper alloy concentration is greater than the sidewall copper alloy concentration; and   a dielectric layer formed over the ILD layer and the copper alloy material.   
     
     
         2 . The structure of  claim 1 , wherein:
 the copper alloy material comprises a doped region of CuMn having a manganese concentration of greater than 0.5% atomic; and   the dielectric layer comprises an NBLoK (SiC(N,H)) layer.   
     
     
         3 . The structure of  claim 1 , wherein the copper line has a thickness of about 3 microns (μm). 
     
     
         4 . The structure of  claim 1 , wherein:
 the top surface of the copper line is directly doped with a copper alloy material comprising a high concentration CuMn seed layer having a manganese concentration of about 2.0% atomic; and   the dielectric layer comprises NBLoK (SiC(N,H)).   
     
     
         5 . The structure of  claim 4 , wherein the copper line is formed on a low concentration CuMn seed layer having a manganese concentration of about 0.5% atomic or less.