Method for enhancing the adhesion of copper deposited by chemical vapor deposition

Abstract

The present invention provides a method for improving the adhesion of copper and other metal-comprising conductive metals to a barrier layer. A barrier is provided that has a first surface that is substantially unoxidized, wherein at least a portion of the surface is free from the presence of oxygen atoms. A conductive layer is then deposited onto the first surface of the barrier layer. The substantially unoxidized state of the first surface enhances the adhesion of the metal-comprising layer to the barrier layer. The method is particularly useful in obtaining excellent adhesion of a copper nucleation layer to an underlying barrier layer surface.

What is claimed is:  
     
         1 . A method for depositing copper, comprising: 
 (a) providing a barrier layer having a first surface that is substantially unoxidized; and    (b) depositing a first copper layer onto the first surface of the barrier layer.    
     
     
         2 . The method of  claim 1 , wherein the barrier layer has an adhesion promoting top layer on which the first surface is disposed.  
     
     
         3 . The method of  claim 1 , wherein the first copper layer is deposited by chemical vapor deposition (CVD).  
     
     
         4 . The method of  claim 1 , wherein the first copper layer is deposited by physical vapor deposition (PVD).  
     
     
         5 . The method of  claim 1 , wherein the first copper layer is deposited by electroless plating.  
     
     
         6 . The method of  claim 1 , wherein the first copper layer is deposited by electroplating.  
     
     
         7 . The method of  claim 1 , wherein the first surface of the barrier layer includes a noble metal, in a quantity sufficient to affect the tendency of the first surface of the barrier layer to oxidize.  
     
     
         8 . The method of  claim 7 , wherein the first surface of the barrier layer includes one or more metals selected from the group consisting of gold (Au), silver (Ag), platinum (Pt), chromium (Cr), nickel (Ni), and palladium (Pd), in a quantity sufficient to affect the tendency of the first surface of the barrier layer to oxidize.  
     
     
         9 . The method of  claim 8 , wherein the first surface of the barrier layer consists essentially of one or more metals selected from the group consisting of gold (Au), silver (Ag), platinum (Pt), chromium (Cr), nickel (Ni), and palladium (Pd), in a quantity sufficient to affect the tendency of the first surface of the barrier layer to oxidize.  
     
     
         10 . The method of  claim 9 , wherein said barrier layer is subsequently used as a seed layer for the electroless plating of copper.  
     
     
         11 . The method of  claim 9 , wherein the first surface of the barrier layer consists essentially of gold (Au).  
     
     
         12 . The method of  claim 9 , wherein the first surface of the barrier layer consists essentially of silver (Ag).  
     
     
         13 . The method of  claim 9 , wherein the first surface of the barrier layer consists essentially of platinum (Pt).  
     
     
         14 . The method of  claim 9 , wherein the first surface of the barrier layer consists essentially of Nickel (Ni).  
     
     
         15 . The method of  claim 9 , wherein the first surface of the barrier layer consists essentially of palladium (Pd).  
     
     
         16 . The method of  claim 7 , wherein the noble metal is added to the barrier layer by ion implantation.  
     
     
         17 . The method of  claim 1 , wherein the first surface of the barrier layer includes a refractory metal that forms a volatile oxide, in a quantity sufficient to affect the tendency of the first surface of the barrier layer to oxidize.  
     
     
         18 . The method of  claim 17 , wherein the first surface of the barrier layer includes one or more metals selected from the group consisting of tungsten (W) and molybdenum (Mo), in a quantity sufficient to affect the tendency of the first surface of the barrier layer to oxidize.  
     
     
         19 . The method of  claim 18 , wherein the first surface of the barrier layer consists essentially of one or more metals selected from the group consisting of tungsten (W) and molybdenum (Mo), in a quantity sufficient to affect the tendency of the first surface of the barrier layer to oxidize.  
     
     
         20 . The method of  claim 19 , wherein the first surface of the barrier layer consists essentially of tungsten (W).  
     
     
         21 . The method of  claim 19 , wherein the first surface of the barrier layer consists essentially of molybdenum (Mo).  
     
     
         22 . The method of  claim 1 , wherein the first copper layer is deposited from a precursor containing less than about 2,000 ppm of water.  
     
     
         23 . The method of  claim 1 , wherein the first surface that is substantially unoxidized is provided by removing oxide from the surface of barrier layer.  
     
     
         24 . The method of  claim 23 , wherein the oxide is removed using a process selected from the group consisting of ion bombardment, reactive cleaning by contact with a gas which reacts with the oxide to produce a volatile reaction product, and reactive cleaning by contact with a plasma species which reacts with the oxide to produce a volatile reaction product.  
     
     
         25 . The method of  claim 1 , wherein the environment to which the first surface of the barrier layer is exposed, and the period of time that is allowed to elapse, between the completion of step (a) and the beginning of step (b), are controlled such that a substantial amount of oxide does not form on the first surface of the barrier layer.  
     
     
         26 . The method of  claim 1 , wherein the deposition of Cu is started while the deposition o the barrier layer is still proceeding, and wherein the first surface refers to the part of the barrier layer deposited just before the deposition of Cu is started.  
     
     
         27 . The method of  claim 1 , wherein the copper layer is deposited by CVD, and wherein a precursor used to deposit the first copper layer is combined with a material of the barrier layer prior to deposition during the period of time after step (b) is started and before step (a) is completed.  
     
     
         28 . The method of  claim 1 , further comprising the step of depositing a second copper layer onto the first copper layer by chemical vapor deposition (CVD) using process parameters different than those used in step (b).  
     
     
         29 . The method of  claim 1 , further comprising the step of depositing a second copper layer onto the first copper layer by physical vapor deposition (PVD) using process parameter different than those used in step (b).  
     
     
         30 . A method for depositing layers onto a substrate, comprising: 
 (a) depositing a barrier layer onto a substrate, wherein a first surface of the barrier layer includes a noble metal in a quantity sufficient to affect the tendency of the first surface of the barrier layer to oxidize;    (b) depositing a first copper layer by chemical vapor deposition (CVD) onto the first surface of the barrier layer.    
     
     
         31 . A method for depositing layers onto a substrate, comprising: 
 (a) depositing a barrier layer onto a substrate, wherein a first surface of the barrier layer includes refractory metals that form volatile oxides, in a quantity sufficient to affect the tendency of the first surface of the barrier layer to oxidize;    (b) depositing a first copper layer by chemical vapor deposition (CVD) onto a first surface of the barrier layer.    
     
     
         32 . A method for depositing layers onto a substrate, comprising: 
 (a) depositing a barrier layer onto a substrate;    (b) depositing a first copper layer by chemical vapor deposition (CVD) onto a first surface of the barrier layer, wherein the first copper layer is deposited from a precursor that contains less than about 2,000 ppm of water.    
     
     
         33 . A method for depositing layers onto a substrate, comprising: 
 (a) depositing a barrier layer onto a substrate;    (b) removing oxide from a surface of barrier layer;.    (c) depositing a first copper layer by chemical vapor deposition (CVD) onto the surface of the barrier layer.    
     
     
         34 . A method for depositing layers onto a substrate, comprising: 
 (a) depositing a barrier layer onto a substrate; and    (c) depositing a first copper layer by chemical vapor deposition (CVD) onto the surface of the barrier layer;    wherein the environment to which the first surface of the barrier layer is exposed, and the period of time that is allowed to elapse, between the completion of step (a) and the beginning of step (b), are controlled such that a substantial amount of oxide does not form on the first surface of the barrier layer.    
     
     
         35 . A method for depositing layers onto a substrate, comprising: 
 (a) depositing a barrier layer onto a substrate;    (b) depositing a first copper layer by chemical vapor deposition (CVD) onto the surface of the barrier layer, wherein, wherein the deposition of Cu is started while the deposition of the barrier layer is still proceeding.    
     
     
         36 . A semiconductor wafer comprising: 
 a barrier layer; and    a copper layer deposited onto the barrier layer;    wherein the interface between the barrier layer and the copper layer is substantially free of oxides.    
     
     
         37 . A method of preventing particulate formation during processing of a semiconductor substrate, wherein said processing includes deposition of a copper layer either by CVD or by electroless plating of copper, said method comprising depositing a non-oxidizing layer of material upon process apparatus surfaces prior to initiation of said deposition of said copper layer, whereby excess copper which is not deposited upon said semiconductor substrate is adhered to said non-oxidized layer of material which is present upon said process apparatus surfaces.