Method for planarization during plating

Abstract

A method and apparatus are provided for plating metal onto a substrate. The method generally includes applying a plating solution comprising at least a leveler to a substrate; substantially filling features in the substrate by plating metal ions from the plating solution onto the substrate, and applying sonic energy to the plating solution across a surface of the substrate prior to completely filling the features.

1 . A method for plating a metal onto a substrate, comprising: 
 applying a plating solution to a substrate, wherein the plating solution comprises at least a leveler;    substantially filling features in the substrate by plating metal ions from the plating solution onto the substrate; and    applying sonic energy to the plating solution across a surface of the substrate prior to completely filling the features.    
   
   
       2 . The method of  claim 1 , wherein the sonic energy has a frequency in a range of about 400 kilohertz (kHz) to about 9 megahertz (MHz).  
   
   
       3 . The method of  claim 1 , wherein the applying sonic energy to the plating solution comprises applying a power of about 300 W.  
   
   
       4 . The method of  claim 1 , wherein the applying sonic energy to the plating solution comprises applying a current of about 40 Amperes.  
   
   
       5 . The method of  claim 1 , wherein the leveler is selected from the group consisting of thiadiazole, imidazole, nitrogen containing organics, organic acid amides, amine compounds, and combinations thereof.  
   
   
       6 . The method of  claim 1 , wherein the feature comprises at least one opening and a field surrounding the opening.  
   
   
       7 . The method of  claim 6 , wherein the opening has a width less than 2.0 μm.  
   
   
       8 . The method of  claim 1 , wherein the metal ions comprise copper ions.  
   
   
       9 . The method of  claim 1 , further comprising providing a plating cell comprising at least one anode and cathode, wherein the cathode comprises at least a portion of the conductive surface of the substrate.  
   
   
       10 . The method of  claim 9 , further comprising applying current between the at least one anode and the cathode to generate an electroplating current density, wherein the current density is about 60 mA/cm 2 .  
   
   
       11 . A method for plating a metal onto a substrate, comprising: 
 applying a plating solution to a substrate, wherein the plating solution comprises a leveler, a copper ion source, and a supporting electrolyte;    applying uniform agitation to the plating solution; and    substantially filling features in the substrate by plating copper ions from the plating solution onto the substrate.    
   
   
       12 . The method of  claim 11 , wherein the supporting electrolyte comprises acid and water.  
   
   
       13 . The method of  claim 11 , wherein the uniform agitation comprises applying sonic energy.  
   
   
       14 . The method of  claim 13 , wherein the sonic energy has a frequency in a range of about 400 kilohertz (kHz) to about 9 megahertz (MHz).  
   
   
       15 . The method of  claim 14 , wherein the applying sonic energy to the plating solution comprises applying a power of about 300 W.  
   
   
       16 . The method of  claim 11 , wherein the leveler is selected from a group comprising organic acid amides and amine compounds.  
   
   
       17 . An electrochemical plating cell, comprising: 
 an anolyte chamber configured to contain an anolyte solution;    a catholyte chamber configured to contain a catholyte solution for plating a metal onto a substrate;    a membrane positioned to separate the catholyte chamber from the anolyte chamber;    an anode positioned in the anolyte chamber; and    at least one sonic transducer positioned in the catholyte chamber to direct sonic energy toward the substrate.    
   
   
       18 . The electrochemical plating cell of  claim 17 , wherein the sonic transducer produces sonic energy between about 400 kHz and about 9 MHz.  
   
   
       19 . The electrochemical plating cell of  claim 18 , wherein the sonic transducer produces sonic energy between about 0.1 watts/cm 2  and about 10 watts/cm 2 .  
   
   
       20 . The electrochemical plating cell of  claim 17 , wherein the sonic transducer is configured to direct sonic energy toward a surface of the substrate at an angle from approximately 50 to 80 degrees from normal to the substrate surface.