Methods of fabricating electronic devices using direct copper plating

Abstract

The present invention relates to methods and structures for the metallization of semiconductor devices. One aspect of the present invention is a method of forming a semiconductor device having copper metallization. In one embodiment, the method includes providing a patterned wafer having a diffusion barrier for copper; depositing a copperless seed layer on the diffusion barrier effective for electrochemical deposition of gapfill copper. The seed layer is formed by a conformal deposition process and by a nonconformal deposition process. The method further includes electroplating copper gapfill onto the seed layer. Another aspect of the invention includes electronic devices made using methods and structures according to embodiments of the present invention.

What is claimed is: 
     
         1 . A method of manufacturing a semiconductor device having copper metallization, the method comprising:
 providing a patterned semiconductor device wafer;   using atomic layer deposition to deposit a tantalum nitride diffusion barrier for copper;   depositing a ruthenium seed layer by atomic layer deposition to form a conformal portion of the seed layer and chemical vapor deposition to form a nonconformal portion of the seed layer so that the seed layer is effective for direct electrochemical deposition of gapfill copper; and   electroplating a copper gapfill layer onto the ruthenium seed layer.   
     
     
         2 . The method of  claim 1 , wherein the atomic layer deposition and chemical vapor deposition exclude oxygen compounds or oxygen. 
     
     
         3 . The method of  claim 1 , further comprising treating the barrier layer surface in a hydrogen containing plasma before deposition of the ruthenium seed layer. 
     
     
         4 . The method of  claim 1 , wherein the atomic layer deposition excludes oxygen compounds or oxygen and is performed before the chemical vapor deposition. 
     
     
         5 . A seed layer for electrochemical plating of copper metallization in a semiconductor device structure comprising a conformal deposit of a portion of the seed layer and a nonconformal deposit of a portion of the seed layer. 
     
     
         6 . The seed layer of  claim 5 , wherein the seed layer comprises ruthenium. 
     
     
         7 . The seed layer of  claim 5 , wherein the seed layer is deposited on a diffusion barrier for copper. 
     
     
         8 . The seed layer of  claim 5 , wherein the seed layer is deposited on a barrier layer comprising tantalum nitride. 
     
     
         9 . The seed layer of  claim 5 , wherein the seed layer is deposited on a barrier layer comprising tantalum, tungsten nitride, tungsten carbon nitride, tantalum nitride, tantalum carbon nitride, titanium nitride, titanium silicon nitride, or combinations thereof. 
     
     
         10 . The seed layer of  claim 5 , wherein the conformal deposit is formed by atomic layer deposition. 
     
     
         11 . The seed layer of  claim 5 , wherein the nonconformal deposit is formed by chemical vapor deposition. 
     
     
         12 . The seed layer of  claim 5 , wherein the nonconformal deposit is formed by physical vapor deposition. 
     
     
         13 . The seed layer of  claim 5 , wherein the nonconformal deposit is formed by metal evaporation or sputtering. 
     
     
         14 . The seed layer of  claim 5 , wherein the conformal deposit is formed by atomic layer deposition and the nonconformal deposit is formed by chemical vapor deposition. 
     
     
         15 . The seed layer of  claim 5 , wherein the conformal deposit is formed by atomic layer deposition and the nonconformal deposit is formed by physical vapor deposition. 
     
     
         16 . The seed layer of  claim 5 , wherein the conformal deposit is formed by atomic layer deposition or chemical vapor deposition and the nonconformal deposit is formed by chemical vapor deposition or physical vapor deposition. 
     
     
         17 . The seed layer of  claim 5 , wherein the nonconformal deposit is thicker over the field areas than in patterned features of the semiconductor device. 
     
     
         18 . The seed layer of  claim 5 , wherein the nonconformal deposit has an electrical resistance sufficiently low for electrochemical plating gapfill copper. 
     
     
         19 . A semiconductor device made using the method of  claim 1 . 
     
     
         20 . A semiconductor device made using the seed layer of  claim 5 . 
     
     
         21 . A method of manufacturing a semiconductor device having copper metallization, the method comprising:
 providing a patterned semiconductor device wafer;   using atomic layer deposition to deposit a tantalum nitride diffusion barrier for copper;   treating the barrier layer surface in a hydrogen containing plasma;   depositing a ruthenium seed layer by atomic layer deposition to form a conformal portion of the seed layer and chemical vapor deposition to form a nonconformal portion of the seed layer so that the seed layer is effective for direct electrochemical deposition of gapfill copper; and   electroplating a copper gapfill layer onto the ruthenium seed layer.   
     
     
         22 . A semiconductor device having copper metallization made using a method comprising:
 providing a patterned wafer having a diffusion barrier for copper;   depositing a copperless seed layer on the diffusion barrier effective for direct electrochemical deposition of gapfill copper, the seed layer being formed by a conformal deposition process and by a nonconformal deposition process; and   electroplating copper gapfill onto the seed layer.