Method of reducing stress corrosion induced voiding of patterned metal layers

Abstract

Stress corrosion induced voiding of patterned metal layers is avoided or substantially reduced by removing etching residues before gap filling. Embodiments include etching an Al or Al alloy layer employing fluorine and/or chlorine chemistry, wet cleaning, treating with a nitrogen-containing plasma at a temperature of at least about 400° C. and gap filling with a dielectric material, e.g. HDP oxide by HDP CVD.

What is claimed is:  
     
         1 . A method of manufacturing a semiconductor device, the method comprising: 
 forming a patterned metal layer comprising metal features having side surfaces with gaps therebetween; and    treating the patterned metal layer with a nitrogen-containing plasma.    
     
     
         2 . The method according to    claim 1   , comprising sequentially: 
 forming a metal layer;    etching the metal layer to form the patterned metal layer;    wet cleaning the patterned metal layer;    treating the patterned metal layer with a nitrogen-containing plasma; and    depositing a dielectric material in the gaps.    
     
     
         3 . The method according to    claim 2   , comprising depositing a high density plasma oxide by high density plasma chemical vapor deposition to fill the gaps.  
     
     
         4 . The method according to    claim 3   , comprising treating the patterned metal layer with the nitrogen-containing plasma and depositing the high density plasma oxide in the same tool.  
     
     
         5 . The method according to    claim 2   , comprising wet cleaning with a solvent.  
     
     
         6 . The method according to    claim 2   , comprising etching the metal layer employing an etching recipe comprising fluorine and/or chlorine.  
     
     
         7 . The method according to    claim 6   , wherein: 
 etching and/or wet cleaning result in the formation of residues which can attack the side surface of the metal feature; and    the nitrogen-containing plasma treatment substantially removes the residues before depositing the dielectric material.    
     
     
         8 . The method according to    claim 6   , comprising treating the patterned metal layer with the nitrogen-containing plasma at a temperature of at least about 400° C.  
     
     
         9 . The method according to    claim 8   , comprising treating the patterned metal layer with the nitrogen-containing plasma at a: 
 nitrogen flow rate of about 1,000 to about 5,000 sccm;    source power of about 500 to about 2,500 watts;    bias power of about 200 to about 2,800 watts;    temperature of about 350 to about 420° C.; and    pressure of about 1.4 to about 3.0 Torr.    
     
     
         10 . The method according to    claim 9   , comprising treating the patterned metal layer with the nitrogen-containing plasma for about 20 to about 70 seconds.  
     
     
         11 . The method according to    claim 1   , wherein the metal layer is a composite comprising: 
 a lower barrier layer;    an intermediate primary conductive layer; and    an anti-reflective coating on the intermediate layer.    
     
     
         12 . The method according to    claim 11   , wherein: 
 the barrier layer comprises titanium, titanium-tungsten, titanium nitride, or titanium-titanium nitride;    the intermediate primary conductive layer comprises aluminum or an aluminum alloy; and    the anti-reflective coating comprises titanium-titanium nitride.    
     
     
         13 . The method according to    claim 12   , wherein the barrier layer comprises titanium nitride.  
     
     
         14 . The method according to    claim 12   , wherein the aluminum alloy contains copper.