Electropolishing and electroplating methods

Abstract

In one aspect of the present invention, an exemplary method is provided for electroplating a conductive film on a wafer. The method includes electroplating a metal film on a semiconductor structure having recessed regions and non-recessed regions within a first current density range before the metal layer is planar above recessed regions of a first density, and electroplating within a second current density range after the metal layer is planar above the recessed regions. The second current density range is greater than the first current density range. In one example, the method further includes electroplating in the second current density range until the metal layer is planar above recessed regions of a second density, the second density being greater than the first density, and electroplating within a third current density range thereafter.

1 . A method for electroplating a metal layer on a semiconductor structure having recessed regions and non-recessed regions, comprising: 
 electroplating within a first current density range before the metal layer is planar above recessed regions of a first density; and    electroplating within a second current density range after the metal layer is planar above the recessed regions, wherein the second current range is greater than the first current range.    
   
   
       2 . The method of  claim 1 , wherein the first current density range is between 0.5 mÅ/cm 2  and 5 mÅ/cm 2 , and the second current density range is between 5 mÅ/cm 2  and 30 mÅ/cm 2 .  
   
   
       3 . The method of  claim 1 , wherein electroplating within the first current density range is carried out at a constant current density.  
   
   
       4 . The method of  claim 1 , wherein electroplating within the first current density range is carried out at an increasing current density.  
   
   
       5 . The method of  claim 4 , wherein the first current density increases linearly.  
   
   
       6 . The method of  claim 4 , wherein the first current density increases non-linearly.  
   
   
       7 . The method of  claim 1 , wherein electroplating within the first current density range includes decreasing the current density.  
   
   
       8 . The method of  claim 1 , wherein electroplating within the second current density range is carried out at a constant current density.  
   
   
       9 . The method of  claim 1 , wherein electroplating within the second current density range is carried out at an increasing current density.  
   
   
       10 . The method of  claim 9 , wherein the second current density increases non-linearly.  
   
   
       11 . The method of  claim 1 , wherein electroplating within the second current density range is carried out at a decreasing current density.  
   
   
       12 . The method of  claim 1 , wherein the recessed regions of a first density include recesses with a size between 0.035 to 0.5 microns and spacing in the range of 0.035 to 0.5 microns, and 
 a large recess with a dummy structure having a size between 0.05 and 2.0 microns and spacing in the range 0.05 and 2.0 microns.    
   
   
       13 . The method of  claim 12 , wherein the metal layer is electroplated above the regions of the first density until the metal layer is planar above the regions of the first density, and 
 electroplating over a region of second density until the metal layer is planar above the region of first density and the region of second density, wherein the region of second density is greater than the region of first density.    
   
   
       14 . The method of  claim 13 , wherein after the metal layer is planar above the region of second density and the region of first density, electroplating at a third current density greater than the second current density.  
   
   
       15 . The method of  claim 1 , wherein the metal layer is electroplated with an electrolyte fluid including an accelerator, suppressor, and leveler.  
   
   
       16 . The method of  claim 15 , wherein the accelerator concentration is between 1.5 and 2.5 ml/liter, the suppressor concentration is between 7 and 9 ml/liter, and the leveler concentration is between 1.25 and 1.75 ml/liter.  
   
   
       17 . The method of  claim 1 , further including controlling the grain size of the metal layer with additives in the electrolyte fluid.  
   
   
       18 . The method of  claim 17 , wherein the additives include at least one of a brightener, accelerator, suppressor, and leveler  
   
   
       19 . The method of  claim 1 , further including rotating the semiconductor structure with a chuck at a rotation speed of 50-200 rpm.  
   
   
       20 . The method of  claim 1 , further including rotating the semiconductor structure with a chuck at a rotation speed of 125 rpm.  
   
   
       21 - 78 . (canceled)