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.

What is claimed is:  
     
         1 . A method for plating metal onto a substrate, comprising: 
 forming a metal layer in the features by plating metal ions from a first solution in features formed into the substrate under a first applied current density, wherein the first solution comprises an acid in an amount sufficient to provide a first solution pH of less than about 6, copper ions, and at least one suppressor; and    substantially filling the features by plating metal ions from a second solution in the features under a second applied current density, wherein the second solution comprises an acid in an amount sufficient to provide a second solution pH of between about 0.6 and about 4, copper ions, at least one suppressor and at least one accelerator.    
     
     
         2 . The method of  claim 1 , further comprising forming the metal layer on a metal seed layer formed on the surface of the substrate.  
     
     
         3 . The method of  claim 2 , wherein the metal seed layer has a thickness of between about 50 Å and about 1500 Å.  
     
     
         4 . The method of  claim 3 , wherein the metal seed layer is discontinuous.  
     
     
         5 . The method of  claim 3 , wherein the metal seed layer is continuous  
     
     
         6 . The method of  claim 2  wherein the first solution has a resistance that is greater than a resistance of the seed layer.  
     
     
         7 . The method of  claim 1 , wherein the first applied current density is between about 0.5 mA/cm 2  and about 5 mA/cm 2 .  
     
     
         8 . The method of  claim 1 , wherein the first applied current density is between about 0.5 mA/cm 2  and about 3 mA/cm 2 .  
     
     
         9 . The method of  claim 1 , wherein the first solution comprises copper sulfate in a concentration of between about 2 g/L and about 50 g/L.  
     
     
         10 . The method of  claim 1 , wherein the first solution comprises copper sulfate in a concentration of between about 2 g/L and about 20 g/L.  
     
     
         11 . The method of  claim 1 , wherein the second solution comprises a copper alloy solution.  
     
     
         12 . The method of  claim 1 , wherein the first solution comprises a copper alloy.  
     
     
         13 . The method of  claim 12 , wherein the second solution comprises copper sulfate.  
     
     
         14 . The method of  claim 12 , wherein the second solution comprises a copper alloy.  
     
     
         15 . The method of  claim 1 , wherein the first solution pH is between about 1 and about 4.  
     
     
         16 . The method of  claim 1 , wherein the first solution pH is between about 2 and about 3.  
     
     
         17 . The method of  claim 1 , wherein the first solution further comprises chlorine ions in a concentration of between about 10 ppm and about 100 ppm.  
     
     
         18 . The method of  claim 1 , wherein each of the one or more suppressors have a molecular weight of greater than about 500.  
     
     
         19 . The method of  claim 1 , wherein each of the one or more suppressors have a molecular weight of between about 1000 and about 10,000.  
     
     
         20 . The method of  claim 1 , further comprising rinsing the substrate surface with a deionized water rinsing solution.  
     
     
         21 . The method of  claim 20 , wherein the rinsing solution comprises deionized water and chlorine in a concentration of less than about 1 ppm.  
     
     
         22 . The method of  claim 1 , further comprising forming the metal layer on a copper barrier layer formed on the surface of the substrate.  
     
     
         23 . A method for depositing a metal on a substrate having features and field areas, comprising: 
 substantially filling the features by plating metal ions from a first solution in the features under a first applied current, wherein the first plating solution comprises an acid in an amount sufficient to provide a first solution pH of from about 0.6 to about 3, copper ions, and at least one suppressor and at least one accelerator; and    growing a film layer on the field areas by plating metal ions from a second plating solution under a second applied current to form a metal layer on the substrate, 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 the second applied current has a current density that is greater than a current density of the first applied current.    
     
     
         24 . The method of  claim 23 , wherein the first plating solution comprises sulfuric acid in a concentration of from about 5 g/L to about 10 g/L.  
     
     
         25 . The method of  claim 23 , wherein the first applied current has a current density of between about 0.5 mA/cm 2  about 5 mA/cm 2 .  
     
     
         26 . The method of  claim 23 , wherein the second applied current has a current density of greater than about 30 mA/cm 2 .  
     
     
         27 . A method for plating metal onto a substrate, comprising: 
 depositing a metal seed layer on the surface of the substrate, the surface comprising field areas and features;    substantially filling the features by plating a metal from a first solution onto the metal seed layer to form a first fill layer, wherein the first solution comprises an acid in an amount sufficient to provide a first solution pH of between about 0.5 and about 6, copper ions, and at least one suppressor;    substantially filling features on the substrate by plating metal ions from a second solution onto the first fill layer to form a second fill layer, wherein the second solution comprises 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 second fill layer with a third solution, wherein the third solution comprises an acid, copper ions, at least one suppressor, at least one accelerator, and at least one leveling agent.    
     
     
         28 . A first plating solution for plating metal on a metal seed layer, comprising: 
 copper sulfate in a concentration of between about 5 g/L and about 50 g/L;    sulfuric acid in a concentration sufficient to provide a pH of between about 0.5 and 6; and    suppressors having a molecular weight of greater than about 500.