Methods for Passivating Metallic Interconnects

Abstract

One or more embodiments of the present invention relates to a method for passivating metallic interconnects, said method including: forming a metallic conductor embedded in at least one surrounding dielectric layer, said metallic conductor including a metal or alloy chosen from a group consisting of Cu, Ag, and alloys including one or more of these metals, said metallic conductor and said at least one surrounding dielectric layer having top surfaces; and forming a capping passivation film directly on the top surface of the metallic conductor, but not over the top surface of the at least one surrounding dielectric layer, wherein said capping passivation film including one or more materials selected from the group consisting of copper sulfide, silver sulfide, copper selenide, silver selenide, copper telluride, and silver telluride, wherein the copper sulfide refers to CuS X or Cu 2 S X , the silver sulfide refers to AgS X or Ag 2 S X , the copper selenide refers to CuSe X or Cu 2 Se X , and the copper telluride refers to CuTe X or Cu 2 Te X , and wherein 0.7≦X≦1.3.

1 . A method for passivating metallic interconnects, said method comprising:
 forming a metallic conductor embedded in at least one surrounding dielectric layer, said metallic conductor comprising a metal or alloy chosen from a group consisting of Cu, Ag, and alloys comprising one or more of these metals, said metallic conductor and said at least one surrounding dielectric layer having top surfaces; and   forming a capping passivation film directly on the top surface of the metallic conductor, but not over the top surface of the at least one surrounding dielectric layer, wherein said capping passivation film comprising one or more materials selected from the group consisting of copper sulfide, silver sulfide, copper selenide, silver selenide, copper telluride, and silver telluride, wherein the copper sulfide refers to CuS X  or Cu 2 S X , the silver sulfide refers to AgS X  or Ag 2 S X , the copper selenide refers to CuSe X  or Cu 2 Se X , and the copper telluride refers to CuTe X  or Cu 2 Te X , and wherein 0.7≦X≦1.3.   
   
   
       2 . The method of  claim 1  further comprising depositing a capping dielectric barrier layer over the capping passivation film. 
   
   
       3 . The method of  claim 2  wherein the capping passivation film has a thickness in a range from about 10 Å to about 100 Å. 
   
   
       4 . The method of  claim 2  wherein the capping passivation film has a thickness in a range from about 30 Å to about 200 Å. 
   
   
       5 . The method of  claim 2  wherein the capping passivation film has a thickness in a range from about 10 Å to about 50 Å. 
   
   
       6 . The method of  claim 2  wherein the capping dielectric diffusion barrier layer comprises one or more materials selected from a group consisting of silicon nitride, silicon carbide, silicon carbide nitride, silicon carbide nitride oxide, silicon nitride oxide, SiC X H Y , and SiC X O Y H Z . 
   
   
       7 . The method of  claim 2  wherein the capping passivation film is formed in a plasma enhanced chemical vapor deposition (PECVD) chamber. 
   
   
       8 . The method of  claim 7  wherein the PECVD chamber is the same chamber used for depositing the capping dielectric barrier layer. 
   
   
       9 . The method of  claim 2  wherein the capping passivation film comprises copper sulfide. 
   
   
       10 . The method of  claim 9  wherein the capping passivation film has a thickness in a range from about 10 Å to about 100 Å. 
   
   
       11 . The method of  claim 9  wherein the capping passivation film has a thickness in a range from about 30 Å to about 200 Å. 
   
   
       12 . The method of  claim 9  wherein the capping passivation film has a thickness in a range from about 10 Å to about 50 Å. 
   
   
       13 . The method of  claim 9  wherein the capping dielectric diffusion barrier layer comprises one or more materials selected from a group consisting of silicon nitride, silicon carbide, silicon carbide nitride, silicon carbide nitride oxide, silicon nitride oxide, SiC X H Y , and SiC X O Y H Z . 
   
   
       14 . The method of  claim 9  wherein the capping passivation film is formed in a plasma enhanced chemical vapor deposition (PECVD) chamber. 
   
   
       15 . The method of  claim 14  wherein the PECVD chamber is the same chamber used for depositing the capping dielectric barrier layer. 
   
   
       16 . The method of  claim 14  wherein a sulfur-bearing reactant is utilized for sulfidation of the top surface of the metallic conductor. 
   
   
       17 . The method of  claim 16  wherein the sulfur-bearing reactant is selected from a group consisting of H 2 S gas, H 2 S gas mixture, and sublimed sulfur vapor. 
   
   
       18 . The method of  claim 9  wherein the capping passivation film is formed by reacting the top surface of the metallic conductor with a wet solution containing one or more sulfur-bearing compounds. 
   
   
       19 . The method of  claim 18  wherein the wet solution comprises one or more of dissolved elemental sulfur (S n ), sulfide ions (S −2 ), and dissolved H 2 S. 
   
   
       20 . The method of  claim 2  wherein the capping passivation film is formed by reacting the top surface of the metallic conductor with a wet solution containing one or more sulfur-bearing compounds. 
   
   
       21 . A semiconductor device comprising a metallic interconnect passivated by the method of  claim 2 . 
   
   
       22 . A semiconductor device comprising a metallic interconnect passivated by the method of  claim 14 .