Reliability barrier integration for cu application

Abstract

Embodiments of the present invention provide a process sequence and related hardware for filling a patterned feature on a substrate with a metal, such as copper. The sequence comprises first forming a reliable barrier layer in the patterned feature to prevent diffusion of the metal into the dielectric layer through which the patterned feature is formed. One sequence comprises forming a generally conformal barrier layer over a patterned dielectric, etching the barrier layer at the bottom of the patterned feature, depositing a second barrier layer, and then filling the patterned feature with a metal, such as copper.

1 . A method of forming a barrier on a substrate having a recessed feature formed therein, the method comprising: 
 depositing a nitride barrier layer on the substrate;    etching through the nitride barrier layer so as to expose at least a bottom portion of the recessed feature;    depositing an additional nitride barrier layer on the substrate; and    depositing a copper pre-layer on the substrate.    
   
   
       2 . The method of  claim 1 , further comprising depositing copper on the copper pre-layer.  
   
   
       3 . The method of  claim 2 , wherein the depositing copper on the copper pre-layer comprises electroplating copper.  
   
   
       4 . The method of  claim 1 , wherein the deposition of the additional nitride barrier layer is performed in the presence of a high density plasma.  
   
   
       5 . The method of  claim 1 , wherein the additional nitride barrier layer is a TaN layer.  
   
   
       6 . The method of  claim 1 , wherein the depositing a nitride barrier layer comprises a vapor deposition.  
   
   
       7 . A method of forming a barrier on a substrate having a recessed feature formed therein, the method comprising: 
 depositing a nitride barrier layer on the substrate;    etching through the nitride barrier layer so as to expose at least a bottom portion of the recessed feature;    depositing an additional nitride barrier layer on the substrate, wherein the additional nitride barrier layer covers the bottom of the recessed feature; and    depositing a copper layer on the substrate.    
   
   
       8 . The method of  claim 7 , further comprising electroplating copper on the copper layer.  
   
   
       9 . The method of  claim 8 , wherein the electroplating copper on the copper layer fills the recessed feature.  
   
   
       10 . The method of  claim 7 , wherein the deposition of the additional nitride barrier layer is performed in the presence of a high density plasma.  
   
   
       11 . The method of  claim 7 , wherein the additional nitride barrier layer is a TaN layer.  
   
   
       12 . The method of  claim 7 , wherein the depositing a nitride barrier layer comprises a vapor deposition.  
   
   
       13 . A method of forming a barrier on a substrate having a recessed feature formed therein, the method comprising: 
 depositing a nitride barrier layer on the substrate, wherein the nitride barrier layer covers the bottom of the recessed feature, and wherein the depositing a nitride barrier layer comprises etching barrier material from the bottom of the recessed feature after deposition of the barrier material; and then    depositing a copper pre-layer on the substrate.    
   
   
       14 . The method of  claim 13 , wherein etching barrier material from the bottom of the recessed feature exposes the bottom of the recessed feature.  
   
   
       15 . The method of  claim 13 , further comprising depositing copper on the copper pre-layer.  
   
   
       16 . The method of  claim 15 , wherein the depositing copper on the copper pre-layer comprises electroplating copper.  
   
   
       17 . The method of  claim 15 , wherein depositing copper on the copper pre-layer fills the recessed feature.  
   
   
       18 . The method of  claim 13 , wherein the deposition of the nitride barrier layer is performed in the presence of a high density plasma.  
   
   
       19 . The method of  claim 13 , wherein the nitride barrier layer comprises tantalum nitride.  
   
   
       20 . The method of  claim 13 , where the depositing a nitride barrier layer comprises a vapor deposition.  
   
   
       21 . A method of forming a barrier on a substrate having a recessed feature formed therein, the method comprising: 
 depositing a nitride barrier layer on the substrate;    etching through the nitride barrier layer so as to expose at least a bottom portion of the recessed feature;    sputtering additional barrier material from a target onto the substrate; and    depositing a copper pre-layer on the substrate.    
   
   
       22 . The method of  claim 21 , wherein sputtering additional barrier material from a target onto the substrate comprises depositing an additional barrier layer on the substrate.  
   
   
       23 . The method of  claim 22 , wherein the additional barrier layer is a TaN layer.  
   
   
       24 . The method of  claim 21 , wherein the additional barrier material comprises tantalum.  
   
   
       25 . The method of  claim 21 , further comprising depositing copper on the copper pre-layer to fill the recessed feature.  
   
   
       26 . The method of  claim 25 , wherein the depositing copper on the copper pre-layer comprises electroplating copper.  
   
   
       27 . The method of  claim 21 , wherein the sputtering comprises a high density plasma process.