Pad structure for copper interconnection and its formation

Abstract

A semiconductor device with high conductivity interconnection lines formed of high conductivity material, such as copper, is manufactured using tantalum nitride material as barrier material between an aluminum layer, such as the wire bonding layer, and the underlying high conductivity interconnection lines. The tantalum nitride material contains high nitrogen content.

The invention claimed is:  
     
         1 . A semiconductor device, comprising: 
 a semiconductor substrate;    a conductive layer formed on said semiconductor substrate;    a conductive barrier layer formed on said conductive layer wherein said conductive barrier layer is a tantalum nitride material selected from the group consisting of TaN 2 , TaSiN 2 , the combination of TaSiN and TaSiN 2 , and the combination of TaN 2 , TaSiN and TaSiN 2 ; and    an aluminum layer formed on said conductive barrier layer wherein said conductive barrier layer is substantially impervious to the diffusion of aluminum atoms therethrough into said conductive layer and the diffusion of atoms of said conductive layer therethrough into said aluminum layer.    
     
     
         2 . The semiconductor device according to  claim 1 , wherein said conductive layer is a metal selected from the group consisting of copper, copper-based alloys, gold, gold-based alloys, silver, and silver-based alloys.  
     
     
         3 . The semiconductor device according to  claim 1 , wherein said conductive barrier layer has a thickness within the range of about 50 to about 2,000 angstroms.  
     
     
         4 . A semiconductor device, comprising: 
 a semiconductor substrate;    a conductive layer formed on said semiconductor substrate;    a conductive barrier layer formed on said conductive layer wherein said conductive barrier layer is a tantalum nitride material selected from the group consisting of TaN 2  and TaSiN 2 ; and    an aluminum layer formed on said conductive barrier layer wherein said conductive barrier layer is substantially impervious to the diffusion of aluminum atoms therethrough into said conductive layer and the diffusion of atoms of said conductive layer therethrough into said aluminum layer.    
     
     
         5 . The semiconductor device according to  claim 4 , wherein said tantalum nitride material contains a nitrogen content by atomic weight of more than about 30%.  
     
     
         6 . The semiconductor device according to  claim 4 , wherein said tantalum nitride material contains a nitrogen content by atomic weight of less than about 40%.  
     
     
         7 . The semiconductor device according to  claim 4 , wherein said aluminum layer constitutes a wire bonding layer for external connection thereto.  
     
     
         8 . The semiconductor device according to  claim 4 , wherein said conductive layer is in electrical and physical contact with said conductive barrier layer, and said first conductive barrier layer is in electrical and physical contact with said aluminum layer.  
     
     
         9 . A semiconductor device, comprising: 
 a semiconductor substrate;    a conductive layer formed on said semiconductor substrate, wherein said conductive layer is a metal selected from the group consisting of copper, copper-based alloys, gold, gold-based alloys, silver, and silver-based alloys;    a conductive barrier layer formed on said conductive layer wherein said conductive barrier layer is a tantalum nitride material selected from the group consisting of TaN 2 , TaSiN 2 , the combination of TaN 2  and TaSiN 2 , the combination of TaSiN and TaSiN 2 , and the combination of TaN 2 , TaSiN and TaSiN 2 ; and    an aluminum layer formed on said conductive barrier layer; wherein said conductive barrier layer is substantially impervious to the diffusion of aluminum atoms therethrough into said conductive layer and the diffusion of atoms of said conductive layer therethrough into said aluminum layer.    
     
     
         10 . The semiconductor device according to  claim 9 , wherein said conductive barrier layer has a thickness greater than 50 angstroms.  
     
     
         11 . The semiconductor device according to  claim 9 , wherein said tantalum nitride material contains a nitrogen content by atomic weight of more than about 30%.  
     
     
         12 . The semiconductor device according to  claim 9 , wherein said tantalum nitride material contains a nitrogen content by atomic weight of less than about 40%.  
     
     
         13 . The semiconductor device according to  claim 9 , wherein said aluminum layer constitutes a wire bonding layer for external connection thereto.  
     
     
         14 . The semiconductor device according to  claim 9 , wherein said conductive layer is in electrical and physical contact with said conductive barrier layer, and said first conductive barrier layer is in electrical and physical contact with said aluminum layer.  
     
     
         15 . A semiconductor device, comprising: 
 a semiconductor substrate;    a conductive layer formed on said semiconductor substrate, wherein said conductive layer is a metal selected from the group consisting of copper, copper-based alloys, gold, gold-based alloys, silver, and silver-based alloys;    a conductive barrier layer formed on said conductive layer wherein said conductive barrier layer is a tantalum nitride material selected from the group consisting of TaN 2 , TaSiN 2 , the combination of TaN 2  and TaSiN 2 , the combination of TaSiN and TaSiN 2 , and the combination of TaN 2 , TaSiN and TaSiN 2 , and has a thickness within the range of about 50 to about 2,000 angstroms; and    an aluminum layer formed on said conductive barrier layer wherein said aluminum layer constitutes a wire bonding layer for external connection thereto, said conductive layer is in electrical and physical contact with said conductive barrier layer, and said first conductive barrier layer is in electrical and physical contact with said aluminum layer, and said conductive barrier layer is substantially impervious to the diffusion of aluminum atoms therethrough into said conductive layer and the diffusion of atoms of said conductive layer therethrough into said aluminum layer.    
     
     
         16 . The semiconductor device according to  claim 15 , wherein said conductive barrier layer contains a nitrogen content by atomic weight of more than about 30% and less than about 40%.