Reliability barrier integration for Cu application

Abstract

The present invention provides a process sequence and related hardware for filling a hole with copper. The sequence comprises first forming a reliable barrier layer in the hole to prevent diffusion of the copper into the dielectric layer through which the hole is formed. One sequence comprises forming a generally conformal barrier layer over a patterned dielectric, etching the bottom of the hole, depositing a second barrier, and then filling the hole with copper. An alternative sequence comprises depositing a first barrier layer over a blanket dielectric layer, forming a hole through both the barrier layer and the dielectric layer, depositing a generally conformal second barrier layer in the hole, removing the barrier layer from the bottom of the hole, and selectively filling the hole with copper.

1 . A method of depositing a barrier over surfaces of a hole formed in a dielectric layer of a substrate and extending generally therethrough to an underlying conductive layer or conductive feature of the substrate, the method comprising: 
 forming a barrier comprising Ta using a vapor deposition over the surfaces of the hole, wherein the forming a barrier comprises etching a barrier material at the bottom of the hole after conformal deposition of the barrier material, and wherein the etching the barrier material comprises using a noble gas-containing plasma while supplying electrical power including RF;    whereby the barrier formed within said hole is adapted to protect the dielectric adjacent sidewalls of the hole.    
     
     
         2 . The method of  claim 1 , wherein the barrier comprising Ta covers the bottom of the hole.  
     
     
         3 . The method of  claim 2 , wherein the barrier comprising Ta is Ta or TaN.  
     
     
         4 . The method of  claim 1 , wherein the vapor deposition includes high density plasma physical vapor deposition.  
     
     
         5 . The method of  claim 4 , wherein the high density plasma physical vapor deposition comprises using a plasma having an average ion density of greater than 10 11  cm −3 .  
     
     
         6 . The method of  claim 4 , wherein the forming a barrier comprises applying RF power to the substrate during the high density plasma physical vapor deposition.  
     
     
         7 . The method of  claim 1 , wherein the forming a barrier includes depositing Ta or TaN while employing physical vapor deposition with a plasma having an average ion density of greater than 10 11  cm −3 .  
     
     
         8 . The method of  claim 1 , further comprising supplying DC electrical power during the etching a barrier material.  
     
     
         9 . The method of  claim 8 , further comprising adding hydrogen to the noble gas-containing plasma.  
     
     
         10 . The method of  claim 1 , further comprising electrically biasing the substrate during the forming a barrier.  
     
     
         11 . The method of  claim 1 , wherein the forming a barrier comprises depositing Ta or TaN using high density plasma sputter deposition.  
     
     
         12 . The method of  claim 11 , wherein the etching a barrier material is performed in an etch chamber, and the depositing Ta or TaN is performed in a deposition chamber.  
     
     
         13 . The method of  claim 11 , wherein the substrate is electrically biased during the high density plasma sputter deposition.  
     
     
         14 . The method of  claim 1 , further comprising applying an electromagnetic filed to the plasma during the forming a barrier.  
     
     
         15 . The method of  claim 1 , further comprising, after the forming a barrier, depositing a wetting layer of copper within the hole by sputter deposition utilizing a high density plasma.  
     
     
         16 . The method of  claim 15 , wherein the high density plasma has an average ion density of greater than 10 11  cm −3 .  
     
     
         17 . The method of  claim 15 , wherein the depositing a wetting layer comprises inductive coupling of energy into the high density plasma.  
     
     
         18 . The method of  claim 1 , wherein the forming a barrier comprises one or more of CVD processes and PVD processes.  
     
     
         19 . The method of  claim 1 , further comprising depositing a wetting layer of copper in the hole after the forming a barrier.  
     
     
         20 . The method of  claim 19 , further comprising filling the hole with copper following the depositing a wetting layer.  
     
     
         21 . The method of  claim 1 , wherein the barrier material comprises Si x N y .  
     
     
         22 . The method of  claim 1 , wherein a layer of Ta is deposited after the forming a barrier and the etching barrier material.  
     
     
         23 . A method for forming a barrier within a hole defined in a dielectric layer of a substrate, the hole generally extending to an underlying copper layer or copper feature of the substrate, the method comprising: 
 depositing a barrier layer generally conformally within the hole;    etching a previously deposited layer at the bottom of the hole using an argon-containing plasma while supplying RF electrical power; and    wherein the barrier includes at least one of Ta and TaN, and wherein high density plasma physical vapor deposition is employed in forming the barrier;    whereby a barrier is provided protecting the dielectric layer while also promoting interconnection to the underlying copper layer or copper feature.    
     
     
         24 . The method of  claim 23 , wherein DC electrical power is supplied during the etching a previously deposited layer.  
     
     
         25 . The method of  claim 24 , wherein the argon-containing plasma further comprises hydrogen.  
     
     
         26 . The method of  claim 23 , wherein the etching is performed in an etch chamber, and the depositing is performed in a deposition chamber.  
     
     
         27 . The method of  claim 23 , further comprising depositing a copper wetting layer within the hole by sputter deposition utilizing a high density plasma after the barrier is deposited.  
     
     
         28 . The method of  claim 27 , wherein the copper wetting layer is deposited within the hole by sputter deposition utilizing a high density plasma having an average ion density of greater than 10 11  cm −3 .  
     
     
         29 . The method of  claim 28 , wherein the copper wetting layer is deposited within the hole following the depositing a barrier layer and the etching.  
     
     
         30 . The method of  claim 29 , further comprising filling the hole with copper after the depositing the copper wetting layer.  
     
     
         31 . The method of  claim 23 , wherein the high density plasma sputter deposition of the Ta or TaN includes applying RF bias to a substrate support member.  
     
     
         32 . The method of  claim 23 , wherein the barrier is formed by successive deposition of a plurality of barrier layers of differing composition.  
     
     
         33 . The method of  claim 23 , wherein the barrier is formed by one or more of CVD and PVD.  
     
     
         34 . The method of  claim 23 , further comprising, after the etching a previously deposited layer, depositing copper within the hole by a sputter deposition including inductive coupling of energy into the plasma.  
     
     
         35 . The method of  claim 23 , wherein the previously deposited layer that is etched comprises Si x N y .  
     
     
         36 . A method of processing a substrate having a dielectric layer, an underlying patterned copper layer, and a hole formed in the dielectric layer extending generally therethrough to the underlying patterned copper layer, the method comprising: 
 depositing one or more barrier layers generally conformally over the walls of the hole;    etching one or more of the barrier layers preferentially from the bottom of the hole using a noble-gas containing plasma while supplying RF electrical power; and    depositing a Ta-containing barrier layer using a high density plasma sputter deposition.    
     
     
         37 , The method of  claim 36 , wherein the Ta-containing barrier layer covers the bottom of the hole.  
     
     
         38 . The method of  claim 37 , wherein the Ta-containing barrier layer is a Ta layer or a TaN layer.  
     
     
         39 . The method of  claim 38 , wherein the high density plasma sputter deposition comprises using a plasma having an average ion density of greater than 10 11  cm −3 .  
     
     
         40 . The method of  claim 36 , further comprising supplying DC electrical power during the etching the one or more of the barrier layers.  
     
     
         41 . The method of  claim 36 , wherein the depositing one or more barrier layers comprises a vapor deposition.  
     
     
         42 . The method of  claim 36 , further comprising depositing a wetting layer of copper in the hole after the depositing a Ta-containing barrier layer.  
     
     
         43 . The method of  claim 42 , further comprising filling the hole with copper following the depositing a wetting layer.  
     
     
         44 . The method of  claim 36 , further comprising, after the depositing a Ta-containing barrier layer, depositing a wetting layer of copper within the hole by sputter deposition utilizing a high density plasma.  
     
     
         45 . The method of  claim 44 , wherein the high density plasma has an average ion density of greater than 10 11  cm −3 .