Multiple chemistry electrochemical plating method

Abstract

Embodiments of the invention generally include a method and intermediate plating solution for plating metal onto a substrate surface. The method generally includes filling the features and/or growing a film layer on the field areas by plating a metal from a first solution on a seed layer under an applied first current, wherein the first solution includes an acid in an amount sufficient to provide a first solution pH of about 6 or less, copper ions, and at least one suppressor. The method may further include substantially filling features by plating metal ions from a second solution onto the substrate under an applied second current to form a metal layer, wherein the second solution includes an acid in an amount sufficient to provide a second solution pH of from about 0.6 to about 3, copper ions, at least one suppressor and at least one accelerator and growing a film layer on the field areas by contacting the metal layer with a third solution under an applied third current, wherein the third solution includes an acid, copper ions, at least one suppressor, at least one accelerator and at least one leveling agent. The intermediate plating solution generally includes copper sulfate in a concentration of from about 5 g/L to about 50 g/L, sulfuric acid in a concentration sufficient to provide a pH of less than about 6 and suppressors having a molecular weight of 600 or greater.

1 . A method for plating metal onto a substrate, comprising: 
 forming a metal layer in features by plating metal ions from a first solution in the features formed into the substrate, wherein the first solution consists essentially of an acid concentration between 0.1 g/L and 5 g/L, a first solution pH between 3 and 6, copper ions, and at least one suppressor; and    substantially filling the features by plating metal ions from a second solution in the features, wherein the second solution comprises an acid, a second solution pH between 0.6 and 3, copper ions, at least one suppressor, and at least one accelerator.    
   
   
       2 . The method of  claim 1 , wherein the metal layer is formed on a metal seed layer formed on the surface of the substrate.  
   
   
       3 . The method of  claim 2 , wherein the first solution has a resistance that is greater than a resistance of the seed layer.  
   
   
       4 . The method of  claim 1 , wherein the forming a metal layer comprises applying a first current density between about 0.5 mA/cm 2  and about 5 mA/cm 2  to the substrate.  
   
   
       5 . The method of  claim 4 , wherein the substantially filling the features comprises applying a second current density greater than about 30 mA/cm to the substrate.  
   
   
       6 . The method of  claim 1 , wherein the first solution has copper ions formed by adding copper sulfate in a concentration of between about 2 g/L and about 50 g/L.  
   
   
       7 . The method of  claim 6 , wherein the concentration of copper sulfate is between about 2 g/L and about 20 g/L.  
   
   
       8 . The method of  claim 1 , wherein the second solution has an acidity of between 5 g/L to 10 g/L.  
   
   
       9 . The method of  claim 1 , wherein the second solution comprises at least one leveling agent.  
   
   
       10 . The method of  claim 1 , wherein the first solution further has chlorine ions in a concentration of between about 10 ppm and about 100 ppm.  
   
   
       11 . The method of  claim 1 , wherein each of the one or more suppressors have a molecular weight of greater than about 500.  
   
   
       12 . The method of  claim 11 , wherein each of the one or more suppressors have a molecular weight of between about 1000 and about 10,000.  
   
   
       13 . A method for depositing a metal on a substrate having features, comprising: 
 forming a metal layer in the features by plating metal ions from a first solution in the features, wherein the first plating solution has a resistance that is higher than a seed layer resistance upon which the metal layer is formed; and    substantially filling the features by plating metal ions from a second plating solution, wherein the second plating solution comprises an acid, copper ions, at least one suppressor, at least one accelerator, and at least one leveling agent, and wherein said first and second solutions are different.    
   
   
       14 . The method of  claim 13 , wherein the first plating solution comprises sulfuric acid in a concentration of from about 5 g/L to about 10 g/L.  
   
   
       15 . The method of  claim 13 , wherein the forming a metal layer comprises applying a first current at a current density of between about 0.5 mA/cm 2  about 5 mA/cm 2  to the substrate.  
   
   
       16 . The method of  claim 15 , wherein the substantially filling the features comprises applying a second current at a current density of greater than about 30 mA/cm 2  to the substrate.  
   
   
       17 . The method of  claim 13 , further comprising: 
 controlling the plating from the first solution by increasing the first solution resistance to compensate for edge high deposition.    
   
   
       18 . The method of  claim 13 , wherein the first solution has a resistance of between about 40 ohm cm to about 200 ohm cm.  
   
   
       19 . The method of  claim 13 , wherein the first solution comprises an antifoaming agent.  
   
   
       20 . The method of  claim 13 , wherein the second solution further comprises at least one leveling agent.