Increasing electromigration resistance in an interconnect structure of a semiconductor device by forming an alloy

Abstract

By introducing a metallic species into an exposed surface area of a copper region, the electromigration behavior of this surface area may be significantly enhanced. The incorporation of the metallic species may be accomplished in a highly selective manner so as to not unduly affect dielectric material positioned adjacent to the metal region, thereby essentially avoiding undue increase of leakage currents.

1 . A method, comprising:
 forming a mask above a metal region formed in a dielectric material of a metallization layer of a semiconductor device, said mask exposing a surface of said metal region and covering said dielectric material;   applying a metallic species through said mask to said exposed surface of said metal region;   removing said mask; and   forming a dielectric cap material above said metallization layer, said dielectric cap material covering said surface containing said metallic species.   
     
     
         2 . The method of  claim 1 , wherein applying said metallic species comprises performing an ion implantation process to introduce ions of said metallic species into said surface. 
     
     
         3 . The method of  claim 1 , wherein applying said metallic species comprises performing plasma treatment in a plasma ambient containing ions of said metallic species. 
     
     
         4 . The method of  claim 1 , wherein applying said metallic species comprises forming a metal layer comprised of said metallic species on said exposed surface. 
     
     
         5 . The method of  claim 4 , wherein forming said metal layer comprises performing an electrochemical deposition process. 
     
     
         6 . The method of  claim 4 , wherein forming said metal layer comprises depositing said metallic species by at least one of a chemical vapor deposition process and a physical vapor deposition process. 
     
     
         7 . The method of  claim 1 , wherein said metallic species has an atomic radius that is greater than an atomic radius of copper. 
     
     
         8 . The method of  claim 1 , further comprising forming a lower metallization layer prior to forming said metallization layer, wherein said lower metallization layer comprises a metal line, wherein said method further comprises forming said dielectric material above said lower metallization layer, forming a via opening in said dielectric material to expose a portion of said metal line and introducing said metallic species into a surface of said exposed portion. 
     
     
         9 . The method of  claim 8 , wherein said metallic species is introduced by implanting said metallic species through said via opening. 
     
     
         10 . A method, comprising:
 forming a metal layer above a dielectric layer of a metallization layer of a semiconductor device so as to fill an opening in said dielectric layer;   performing an implantation process to introduce a metallic species through an exposed surface of said metal layer; and   removing excess material of said metal layer from said dielectric layer to form a metal region in said dielectric layer, said metal region having a surface comprising said metallic species.   
     
     
         11 . The method of  claim 10 , further comprising forming a conductive barrier material on said dielectric layer and an inner surface of said opening prior to forming said metal layer. 
     
     
         12 . The method of  claim 11 , wherein forming said metal layer comprises depositing said metal layer by performing an electrochemical deposition process. 
     
     
         13 . The method of  claim 10 , wherein said metal layer comprises copper and said metallic species is a non-copper containing species. 
     
     
         14 . The method of  claim 13 , wherein said metallic species has an atomic radius that is greater than an atomic radius of copper. 
     
     
         15 . The method of  claim 10 , wherein forming said metal layer comprises depositing a metal material with a first excess height and removing a portion of said metal material to obtain a second reduced excess height. 
     
     
         16 . The method of  claim 10 , further comprising forming a lower metallization layer prior to forming said metallization layer, wherein said lower metallization layer comprises a metal line and wherein said method further comprises forming said dielectric layer above said lower metallization layer, forming a via opening in said dielectric layer to expose a portion of said metal line and introducing said metallic species into a surface of said exposed portion. 
     
     
         17 . The method of  claim 16 , wherein said metallic species is introduced by implanting said metallic species through said via opening. 
     
     
         18 . A method, comprising:
 forming a via opening in a dielectric layer, said via opening extending to and exposing a portion of a metal region formed in a first metallization layer of a semiconductor device;   performing an ion implantation process to introduce a metallic species into said exposed portion of said metal region; and   filling said via opening with a metal.   
     
     
         19 . The method of  claim 18 , further comprising forming a trench in said dielectric layer, filling said trench with said metal to form a metal line and providing said metallic species at a surface of said metal line. 
     
     
         20 . The method of  claim 19 , wherein providing said metallic species at the surface of said metal line comprises forming a mask above said dielectric layer to expose said surface and applying said metallic species on the basis of said mask. 
     
     
         21 . The method of  claim 19 , wherein providing said metallic species at the surface of said metal line comprises forming a metal layer when filling said trench, introducing said metal species into said metal layer and removing excess material of said metal layer to expose said surface containing said metallic species.