US2005274621A1PendingUtilityA1

Method of barrier layer surface treatment to enable direct copper plating on barrier metal

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Assignee: SUN ZHI-WENPriority: Jun 10, 2004Filed: Dec 9, 2004Published: Dec 15, 2005
Est. expiryJun 10, 2024(expired)· nominal 20-yr term from priority
Inventors:Zhi-Wen SunRenren He
H10P 14/47H10W 20/0526H10W 20/425H10W 20/056H10W 20/052H10W 20/043H10W 20/042H10W 20/033H10P 70/27C25D 7/123C25D 5/34
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Claims

Abstract

Embodiments of a method of barrier layer surface treatment to enable direct copper plating without copper seed layer. In one embodiment, a method of plating copper on a substrate with a group VIII metal layer on top comprises pre-treating the substrate surface by removing a group VIII metal surface oxide layer and/or surface contaminants and plating copper on the pre-treated group VIII metal surface. Pre-treating the substrate can be accomplished by annealing the substrate in an environment with a hydrogen-containing gas environment and/or a non-reactive gas(es) to Ru, by a cathodic treatment in an acid-containing bath, or by immersing the substrate in an acid-containing bath

Claims

exact text as granted — not AI-modified
1 . A method of directly plating copper on a substrate with a group VIII metal layer on the substrate surface, comprising: 
 pre-treating the substrate surface to remove a group VIII metal surface oxide layer and/or organic surface contaminants on the substrate surface to reduce a critical current density during plating; and    plating a continuous and void-free copper layer on the pre-treated substrate surface in an acidic plating bath with a plating current density equaling to or greater than the critical current density.    
   
   
       2 . The method of  claim 1 , wherein the group VIII metal is selected from the group of ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), and platinum (Pt).  
   
   
       3 . The method of  claim 2 , wherein the group VIII metal is ruthenium (Ru).  
   
   
       4 . The method of  claim 1 , wherein the thickness of the group VIII metal is less than about 1000 Å.  
   
   
       5 . The method of  claim 4 , wherein the thickness of the group VIII metal is between about 5 Å to about 200 Å.  
   
   
       6 . The method of  claim 1 , wherein the copper plating is performed within 4 hours after the pre-treatment.  
   
   
       7 . The method of  claim 1 , wherein the critical current density decreases with the increase of the acidity of the plating bath.  
   
   
       8 . The method of  claim 1 , wherein the acidity in the acidic plating bath comes from sulfuric acid, whose concentration is in the range between about 10 g/l to about 300 g/l.  
   
   
       9 . The method of  claim 8 , wherein the critical current density is less than 10 mA/cm 2 .  
   
   
       10 . The method of  claim 1 , wherein the gap group VIII metal surface is more hydrophilic due to the surface pre-treatment.  
   
   
       11 . The method of  claim 1 , wherein pre-treating the substrate is accomplished by annealing the substrate in an environment with a hydrogen-containing gas and/or a gas(es) non-reactive to group VIII metal.  
   
   
       12 . The method of  claim 11 , wherein the annealing gas is a forming gas that contains 4% hydrogen and 96% nitrogen.  
   
   
       13 . The method of  claim 11 , wherein the gas flow rate is between about 1 sccm to about 20 slm.  
   
   
       14 . The method of  claim 11 , wherein the annealing temperature is between about 100° C. to about 400° C.  
   
   
       15 . The method of  claim 11 , wherein the annealing pressure is between about 5 mTorr to about 1500 Torr.  
   
   
       16 . The method of  claim 11 , wherein the annealing duration is between about 2 seconds to about 5 hours.  
   
   
       17 . The method of  claim 1 , wherein the substrate is pre-treated for less than about 1 hour.  
   
   
       18 . The method of  claim 1 , wherein the pre-treatment is performed in an integrated single wafer annealing chamber.  
   
   
       19 . The method of  claim 11 , wherein the pre-treatment is performed in an annealing furnace.  
   
   
       20 . The method of  claim 1 , wherein pre-treating the substrate is accomplished by a cathodic treatment in an acid-containing bath.  
   
   
       21 . The method of  claim 20 , wherein the acid-containing bath has an about 10 g/l to about 100 g/l acid concentration.  
   
   
       22 . The method of  claim 20 , wherein the cathodic is performed at a potential in the range of about 0 volt to about −0.5 volt or at a current density in the range of about 0.05 mA/cm 2  to about 1 mA/cm 2 .  
   
   
       23 . The method of  claim 20 , wherein the pre-treatment duration is in the range of about 2 seconds to about 30 minutes.  
   
   
       24 . The method of  claim 23 , wherein the substrate is pre-treated for less than 5 minutes.  
   
   
       25 . The method of  claim 20 , wherein the acid-containing bath contains sulfuric acid.  
   
   
       26 . The method of  claim 20 , wherein the acid concentration is in the range between 10 g/l to about 50 g/l.  
   
   
       27 . The method of  claim 20 , wherein the acid-containing bath is integrated with the copper plating system.  
   
   
       28 . The method of  claim 1 , wherein the initial plating current of plating copper on the pre-treated group VIII metal surface is at least equal to the critical current density.  
   
   
       29 . A method of directly plating copper on a substrate with a group VIII metal layer on the substrate surface, comprising: 
 pre-treating the substrate surface by annealing the substrate in an environment with a hydrogen-containing gas and/or a gas(es) non-reactive to group VIII metal to reduce a critical current density during plating; and    plating a continuous and void-free copper layer on the pre-treated substrate surface in an acidic plating bath with a plating current density equaling to or greater than the critical current density.    
   
   
       30 . A method of directly plating copper on a substrate with a group VIII metal layer on the substrate surface, comprising: 
 pre-treating the substrate surface by annealing the substrate in an environment with a hydrogen-containing gas and/or a gas(es) non-reactive to group VIII metal to reduce a critical current density during plating; and    plating a continuous and void-free copper layer on the pre-treated substrate surface in an acidic plating bath with a plating current density equaling to or greater than the critical current density within 4 hours after the pre-treatment.    
   
   
       31 . A method of directly plating copper on a substrate with a group VIII metal layer on the substrate surface, comprising: 
 pre-treating the substrate surface to remove a group VIII metal surface oxide layer and/or organic surface contaminants on the substrate surface to reduce a critical current density during plating to below 10 mA/cm 2 ; and    plating a continuous and void-free copper layer on the pre-treated substrate surface in an acidic plating bath with a plating current density equaling to or greater than the critical current density.    
   
   
       32 . A method of directly plating copper on a substrate with a group VIII metal layer on the substrate surface, comprising: 
 pre-treating the substrate surface with a reducing agent to remove a group VIII metal surface oxide layer and/or organic surface contaminants on the substrate surface to reduce a critical current density during plating; and    plating a continuous and void-free copper layer on the pre-treated substrate surface in an acidic plating bath with a plating current density equaling to or greater than the critical current density.

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