Integrated circuit having improved electromigration performance and method of forming same

Abstract

An aspect of the disclosure is directed to a method of forming an interconnect for use in an integrated circuit. The method comprises: forming an opening in a dielectric layer on a substrate; filling the opening with a metal such that an overburden outside of the opening is created; subjecting the metal to a microwave energy dose such that atoms from the overburden migrate to within the opening; and planarizing the metal to a top surface of the opening to remove the overburden, thereby forming the interconnect.

We claim: 
     
         1 . An interconnect in an integrated circuit comprising:
 an opening in a dielectric layer on a substrate; and   a metal layer substantially filling the opening,   wherein a concentration of vacancies within the metal layer is below an equilibrium concentration of vacancies within the metal layer.   
     
     
         2 . The integrated circuit of  claim 1 , further comprising:
 a liner layer substantially coating the opening; and   a seed layer substantially coating the liner layer within the opening and beneath the metal layer.   
     
     
         3 . The integrated circuit of  claim 2 , wherein the liner layer includes at least one of: tantalum, tantalum nitride, tantalum-aluminum nitride, tantalum silicide, titanium, titanium nitride, titanium-silicon nitride, tungsten, cobalt, manganese, and ruthenium and
 wherein the seed layer includes a copper seed layer.   
     
     
         4 . The integrated circuit of  claim 1 , wherein the metal layer includes at least one of: copper, silver, cobalt, or gold. 
     
     
         5 . The integrated circuit of  claim 1 , further comprising:
 a dielectric cap layer over the metal layer.