Field adjusting apparatus for an electroplating bath

Abstract

An electric field adjusting apparatus for adjusting electric field distribution inside an electroplating bath is provided. The electric field adjusting apparatus has a regulation plate with a plurality of evenly distributed through holes. A plurality of evenly distributed through holes with a smaller total through hole area is formed in the regulation plate that corresponds to an area of a plated film on a wafer that conducts a larger current during an electroplating process (close to the edge of the wafer). Meanwhile, a plurality of evenly distributed through holes with a larger total through hole area is formed in the regulation plate that corresponds to an area of the plated film on the wafer that conducts a smaller current during an electroplating process (close to the central region of the wafer). Furthermore, the total area of through holes around a particular location is inversely proportional to the current density in the plated film over the plating object.

1 . An electric field adjusting apparatus inside an electroplating bath with an anode and a cathode therein, wherein the cathode is connected to a wafer, an source metallic rod is connected to the anode and the wafer has a circular plating surface, and the electroplating process includes forming a plated film on the plating surface, comprising: 
 a regulation plate inside the electroplating bath in the space between the source metallic rod and the wafer with the regulation plate set parallel to the plating surface, wherein the regulation plate has a plurality of through hole areas with each through hole area having at least one through hole, total area of the through holes in each one of the through hole areas is inversely proportional to a distribution of current at the corresponding plated film on the plating surface.    
     
     
         2 . The electric field adjusting apparatus of  claim 1 , wherein the regulation plate is fabricated using a non-metallic material being non-conductive.  
     
     
         3 . The electric field adjusting apparatus of  claim 1 , wherein the through hole has a circular shape.  
     
     
         4 . The electric field adjusting apparatus of  claim 1 , wherein the through hole has a rectangular shape.  
     
     
         5 . The electric field adjusting apparatus of  claim 1 , wherein the through hole has an elliptical shape.  
     
     
         6 . An electric field adjusting apparatus inside an electroplating bath with an anode and a cathode therein, wherein the cathode is connected to a plating object, an source metallic rod is connected to the anode and the plating object has a circular plating surface, and the electroplating process includes forming a plated film on the surface of the plating object, comprising: 
 a regulation plate inside the electroplating bath in the space between the source metallic rod and the plating object with the regulation plate set parallel to the plating surface of the plating object, wherein the regulation plate has a plurality of through hole areas with each through hole area having at least one through hole, total area of the through holes in each one of the through hole areas is inversely proportional to the distribution of current at the corresponding plated film on the plating surface.    
     
     
         7 . The electric field adjusting apparatus of  claim 6 , wherein the regulation plate is fabricated using a non-metallic material being non-conductive.  
     
     
         8 . The electric field adjusting apparatus of  claim 6 , wherein the through hole has a circular shape.  
     
     
         9 . The electric field adjusting apparatus of  claim 6 , wherein the through hole has a rectangular shape.  
     
     
         10 . The electric field adjusting apparatus of  claim 6 , wherein the through hole has an elliptical shape.  
     
     
         11 . An electroplating apparatus, comprising: 
 an electroplating bath;    a pool of electrolytic solution inside the electroplating bath;    a power source;    an anode connected to the power source;    a cathode connected to the power source;    a plating object connected to the anode and immersed in the pool of electrolytic solution inside the electroplating bath, wherein the plating object has a plating surface and the electroplating process includes plating a metallic film over the plating surface of the object;    a source metal rod connected to the cathode and immersed in the pool of electrolytic solution inside the electroplating bath; and    a regulation plate inside the electroplating bath in the space between the source metallic rod and the plating object with the regulation plate set parallel to the plating surface, wherein the regulation plate has a plurality of through hole areas with each through hole area having at least one through hole, total area of the through holesin each one of the through hole areas is inversely proportional to the distribution of current at the corresponding plated film on the plating surface.    
     
     
         12 . The electroplating apparatus of  claim 11 , wherein the regulation plate is fabricated using anon-metallic material being non-conductive.  
     
     
         13 . The electroplating apparatus of  claim 11 , wherein the plating object includes a printed circuit board.  
     
     
         14 . The electroplating apparatus of  claim 11 , wherein the plating object includes a wafer.  
     
     
         15 . The electroplating apparatus of  claim 11 , wherein the plating surface is circular.  
     
     
         16 . The electroplating apparatus of  claim 11 , wherein the plating surface is rectangular.  
     
     
         17 . The electroplating apparatus of  claim 11 , wherein the plating surface is polygonal.  
     
     
         18 . The electroplating apparatus of  claim 11 , wherein the apparatus further includes a paddle inserted in the space between the regulation plate and the plating object and immersed in the pool of electrolytic solution for mixing the electrolytic solution thoroughly.  
     
     
         19 . The electroplating apparatus of  claim 11 , wherein the through hole has a circular shape.  
     
     
         20 . The electroplating apparatus of  claim 11 , wherein the through hole has a rectangular shape.  
     
     
         21 . The electroplating apparatus of  claim 11 , wherein the through hole has an elliptical shape.