Modified electroplating solution components in a high-acid electrolyte solution

Abstract

An embodiment of the invention provides a method for reducing electroplating defects by modifying the concentration of components of a high-acid electroplating solution. For one embodiment the suppressor concentration is increased sufficiently to substantially reduce a plurality of electroplating defects while maintaining adequate gap fill. In such an embodiment the concentration of a chloride in the high-acid electroplating solution is determined as low as possible to reduce defects while still sufficient catalyzing the suppressor to maintain adequate gap fill.

1 . A method comprising: 
 determining a concentration of a suppressor for a high-acid electroplating solution such that the suppressor concentration is sufficient to substantially reduce a plurality of electroplating defects; and    determining a concentration of a chloride for the high-acid electroplating solution such that the chloride concentration is sufficient to catalyze the suppressor.    
     
     
         2 . The method of  claim 1  wherein the plurality of electroplating defects include protrusion defects, bare test wafer defects, and pit defects.  
     
     
         3 . The method of  claim 2  wherein the concentration of suppressor is in the range of 3.3 ml/l-20 ml/l.  
     
     
         4 . The method of  claim 3  wherein the concentration of suppressor is approximately 20 ml/l.  
     
     
         5 . The method of  claim 1  wherein the chloride level is in the range of 30 mg/l-65 mg/l.  
     
     
         6 . The method of  claim 1  further comprising: 
 determining a concentration of a leveler for the high-acid electroplating solution, the concentration of leveler determined to reduce within die thickness variation to a specified value.    
     
     
         7 . The method of  claim 6  wherein the leveler concentration is in the range of 8 ml/l-12 ml/l.  
     
     
         8 . The method of  claim 6  further comprising: 
 determining a concentration of an accelerator for the high-acid electroplating solution based upon the chloride concentration and the leveler concentration.    
     
     
         9 . The method of  claim 8  wherein the accelerator concentration is in the range of 1.5 ml/l-3.3 ml/l for a chloride concentration greater than 30 mg/l or a leveler concentration greater than 4 ml/l.  
     
     
         10 . The method of  claim 1  wherein the chloride concentration is determined based upon one or more characteristics of a substrate.  
     
     
         11 . The method of  claim 10  wherein the one or more characteristics of the substrate include feature size and feature aspect ratio.  
     
     
         12 . A high-acid electroplating solution comprising: 
 an acid;    a conductive metal;    a suppressor, a concentration of the suppressor sufficient to substantially reduce a plurality of electroplating defects; and    a chloride, a concentration of the chloride sufficient to catalyze the suppressor.    
     
     
         13 . The high-acid electroplating solution of  claim 12  wherein the plurality of electroplating defects include protrusion defects, bare test wafer defects, and pit defects.  
     
     
         14 . The high-acid electroplating solution of  claim 13  wherein the concentration of suppressor is in the range of 3.3 ml/l-20 ml/l.  
     
     
         15 . The high-acid electroplating solution of  claim 14  wherein the concentration of suppressor is approximately 20 ml/l.  
     
     
         16 . The high-acid electroplating solution of  claim 12  wherein the chloride level is in the range of 30 mg/l-65 mg/l.  
     
     
         17 . The high-acid electroplating solution of  claim 12  further comprising: 
 a leveler, a concentration of the leveler sufficient to reduce within die thickness variation to a specified value.    
     
     
         18 . The high-acid electroplating solution of  claim 17  wherein the leveler concentration is in the range of 4 ml/l-12 ml/l.  
     
     
         19 . The high-acid electroplating solution of  claim 17  further comprising: 
 an accelerator, a concentration of the accelerator based upon the chloride concentration and the leveler concentration.    
     
     
         20 . The high-acid electroplating solution of  claim 19  the accelerator concentration is in the range of 1.5 ml/l-3.3 ml/l for a chloride concentration greater than 30 mg/l or a leveler concentration greater than 8 ml/l.  
     
     
         21 . The high-acid electroplating solution of  claim 12  wherein the chloride concentration is determined based upon one or more characteristics of a substrate.  
     
     
         22 . The high-acid electroplating solution of  claim 21  wherein the one or more characteristics of the substrate include feature size and feature aspect ratio.  
     
     
         23 . An apparatus comprising: 
 a substrate having one or more features formed thereon; and    a layer of conductive metal formed on the substrate by electroplating the substrate using a high-acid electroplating solution, the high-acid electroplating solution including a suppressor concentration sufficient to substantially reduce a plurality of electroplating defects and a chloride concentration sufficient to catalyze the suppressor.    
     
     
         24 . The apparatus of  claim 23  wherein the substrate is silicon and the conductive metal is a metal selected from the group consisting essentially of copper, silver, gold and alloys thereof.  
     
     
         25 . The apparatus of  claim 23  wherein at least one of the plurality of features has a sub-micron dimension and a high aspect ratio.  
     
     
         26 . The apparatus of  claim 23  wherein the plurality of electroplating defects include protrusion defects, bare test wafer defects, and pit defects.  
     
     
         27 . The apparatus of  claim 23  wherein the suppressor concentration is in the range of 3.3 ml/l- 20  ml/l.  
     
     
         28 . The apparatus of  claim 27  wherein the concentration of suppressor is approximately 20 ml/l.  
     
     
         29 . The apparatus of  claim 27  wherein the chloride level is in the range of 30 mg/l-65 mg/l.  
     
     
         30 . The apparatus of  claim 23  wherein the chloride concentration is determined based upon a size and an aspect ratio of one or more of the features.