Wafer electroplating apparatus for improving process uniformity

Abstract

Disclosed is a wafer electroplating apparatus, which includes an electroplating bath comprising an anode in the electroplating bath, an electroplating solution, and a cathode located on the top of the electroplating bath and on to which a wafer is mounted. The cathode comprises a first portion electrically connected to an edge of the wafer, and a second portion extending from the first portion and electrically connected to a side of the wafer. The direct contact of the cathode with the side and front edges of the wafer ensures uniform distribution of the electrical field on the wafer during the electroplating process. Consequently, a uniform thickness of metal film deposition is achieved.

1 . A wafer electroplating apparatus comprising: 
 an electroplating bath;    an anode disposed at a lower portion of the electroplating bath;    an electroplating solution; and    a cathode disposed on the top of the electroplating bath and on to which a wafer is mounted, wherein the cathode comprises a first portion electrically connected to an edge of the wafer, and a second portion extending from the first portion and electrically connected to a side of the wafer.    
   
   
       2 . The wafer electroplating apparatus as set forth in  claim 1 , wherein the second portion of the cathode is sized and shaped to be in contact with side edges of the wafer.  
   
   
       3 . The wafer electroplating apparatus as set forth in  claim 2 , wherein the second portion of the cathode is concave shaped to substantially conform with a convex side edge of the wafer.  
   
   
       4 . The wafer electroplating apparatus as set forth in  claim 1 , wherein the cathode further comprises a third portion, extending from the second portion, provided for aligning the wafer.  
   
   
       5 . The wafer electroplating apparatus as set forth in  claim 4 , wherein the third portion of the cathode is shaped in a slanted pattern inclined outwards and upwards at the top of the electroplating bath.  
   
   
       6 . The wafer electroplating apparatus as set forth in  claim 1 , wherein the cathode is ring shaped and is electrically connected to the entire edge of the wafer.  
   
   
       7 . A wafer electroplating apparatus comprising: 
 an electroplating bath containing a plating solution;    an anode disposed at a lower portion of the electroplating bath ; and, a cathode disposed on the top of the electroplating bath, on to which a wafer is mounted;    wherein the cathode comprises:    a plane portion in direct contact with the side of the wafer;    a concave portion extending from the plane portion and substantially mating with a convex side of the wafer; and    a slanted portion extending from the concave portion and inclined upwards and outwards at the top of the electroplating bath.    
   
   
       8 . The wafer electroplating apparatus as set forth in  claim 7 , wherein the electroplating bath comprises: 
 an inlet through which the electrolyte is supplied into the electroplating bath; and    an outlet through which the spent electrolyte is drained out of the electroplating bath.    
   
   
       9 . The wafer electroplating apparatus of  claim 7 , wherein the electroplating solution comprises an aqueous copper sulfate, and the anode comprises a metal.  
   
   
       10 . The wafer electroplating apparatus of  claim 7 , wherein the cathode is stainless steel.  
   
   
       11 . The wafer electroplating apparatus as set forth in  claim 7 , wherein the cathode is ring shaped and is electrically connected to the entire edge of the wafer.