Method of reducing oxygen content in ECP solution

Abstract

A novel method, which is suitable to substantially reduce the presence of oxygen micro-bubbles in an electroplating bath solution, is disclosed. The method includes the addition of aerobic bacteria to the electroplating bath solution to consume oxygen in the solution. Reduction of the oxygen content in the electroplating bath solution prevents oxygen micro-bubbles from forming in the solution and becoming trapped between the solution and the surface of a metal seed layer on a substrate to block the electroplating of a metal film onto the seed layer. Consequently, the presence of surface pits and other structural defects in the surface of the electroplated metal film is substantially reduced.

1 . A method of electroplating a thin film onto a substrate, comprising:
 providing an electroplating bath solution;   providing aerobic bacteria in said solution;   providing a current source in electrical contact with said substrate;   immersing said substrate in said solution; and   plating the thin film onto said substrate by applying a current to said substrate.   
     
     
         2 . The method of  claim 1  wherein said aerobic bacteria is a nitrifying bacterial agent,  Bdellovibrio bacteriovorus, Acinetobacter calcoaceticus, Pseudamonas fluorescens, Arthrobacter globiformis , or  Acetobacter pasteurianus.    
     
     
         3 . The method of  claim 1  wherein said solution comprises copper sulfate. 
     
     
         4 . The method of  claim 3  wherein said aerobic bacteria is a nitrifying bacterial agent,  Bdellovibrio bacteriovorus, Acinetobacter calcoaceticus, Pseudamonas fluorescens, Arthrobacter globiformis , or  Acetobacter pasteurianus.    
     
     
         5 . The method of  claim 1  wherein said aerobic bacteria is present in said solution in a concentration of about 1 ml/l to 5 ml/l. 
     
     
         6 . The method of  claim 5  wherein said aerobic bacteria is a nitrifying bacterial agent,  Bdellovibrio bacteriovorus, Acinetobacter calcoaceticus, Pseudamonas fluorescens, Arthrobacter globiformis , or  Acetobacter pasteurianus.    
     
     
         7 . The method of  claim 5  wherein said solution comprises copper sulfate. 
     
     
         8 . The method of  claim 7  wherein said aerobic bacteria is a nitrifying bacterial agent,  Bdellovibrio bacteriovorus, Acinetobacter calcoaceticus, Pseudamonas fluorescens, Arthrobacter globiformis , or  Acetobacter pasteurianus.    
     
     
         9 . A method for forming a metal film onto a substrate by:
 providing an electroplating bath solution comprising a metal;   providing aerobic bacteria in a concentration of from about 1 ml/l to about 5 ml/l;   providing a current source in electrical contact with said substrate;   immersing said substrate in said solution; and   applying a current of from about 0.2 mA/cm 2  to about 20 mA/cm 2  to said substrate.   
     
     
         10 . The metal film of  claim 9  wherein said aerobic bacteria is a nitrifying bacterial agent,  Bdellovibrio bacteriovorus, Acinetobacter calcoaceticus, Pseudamonas fluorescens, Arthrobacter globiformis , or  Acetobacter pasteurianus.    
     
     
         11 . The metal film of  claim 9  wherein said electroplating bath solution comprises copper sulfate. 
     
     
         12 . An electrochemical plating solution comprising:
 an electrolyte solution comprising metal; and   an aerobic bacteria provided in said electrolyte solution.   
     
     
         13 . The electrochemical plating solution of  claim 12  wherein said metal is copper, aluminum, nickel, chromium, zinc, tin, gold, silver, lead, or cadmium. 
     
     
         14 . The electrochemical plating solution of  claim 12  wherein said aerobic bacteria is a nitrifying bacterial agent,  Bdellovibrio bacteriovorus, Acinetobacter calcoaceticus, Pseudamonas fluorescens, Arthrobacter globiformis , or  Acetobacter pasteurianus.    
     
     
         15 . The electrochemical plating solution of  claim 12  wherein said aerobic bacteria is present in said electroplating bath solution in a concentration of about 1 ml/l to 5 ml/l. 
     
     
         16 . The electrochemical plating solution of  claim 12  wherein said electroplating bath solution comprises copper sulfate.