Method of wafer plating

Abstract

Provided is a technique for wafer plating treatment that ensures that the plating film thickness becomes uniform on the total area of a plated wafer surface. This method of wafer plating includes: arranging a wafer in an opening of a plating tank; bringing a peripheral side of the wafer and a cathode electrode into contact with each other; supplying a plating liquid; causing the plating liquid that has reached the wafer to flow in the direction of a periphery of a wafer surface to be plated; and supplying a plating current by an anode electrode arranged within the plating tank so as to be opposed to the wafer and the cathode electrode, whereby the wafer is subjected to a plating treatment. In this method, the anode electrode has a shape almost the same shape as the wafer surface to be plated, a plurality of peripheral-edge current supplying sections are provided in a peripheral edge of the anode electrode, and a central current supplying section is provided in a center of the anode electrode. A peripheral-edge plating current supplied from the peripheral-edge current supplying sections and a central plating current supplied from the central current supplying section can be adjusted.

1 . A method of wafer plating comprising the steps of: arranging a wafer on an opening of a plating tank; bringing a peripheral side of the wafer and a cathode electrode into contact with each other; supplying a plating liquid; causing the plating liquid that has reached the wafer to flow in the direction of a periphery of a wafer surface to be plated; and supplying a plating current by an anode electrode arranged within the plating tank so as to be opposed to the wafer and the cathode electrode, whereby the wafer is subjected to a plating treatment,
 wherein the anode electrode has a shape almost the same shape as the wafer surface to be plated, a plurality of peripheral-edge current supplying sections are provided along a peripheral edge of the anode electrode, and a central current supplying section is provided in a center of the anode electrode, and   wherein a peripheral-edge plating current supplied from the peripheral-edge current supplying sections and a central plating current supplied from the central current supplying section are adjusted.   
     
     
         2 . The method of wafer plating claimed in  claim 1 , wherein the anode electrode is formed from a flat plate and the plating current distribution is adjusted by providing a plurality of bores in the flat plate. 
     
     
         3 . The method of wafer plating claimed in  claim 1  wherein the anode electrode is configured such that a platinum film as an intermediate layer is provided on an electrode substrate made of titanium and an iridium oxide film is provided on a surface of the intermediate layer. 
     
     
         4 . The method of wafer plating claimed in  claim 2  wherein the anode electrode is configured such that a platinum film as an intermediate layer is provided on an electrode substrate made of titanium and an iridium oxide film is provided on a surface of the intermediate layer. 
     
     
         5 . The method of wafer plating claimed in  claim 1  wherein the anode electrode comprises from three to ten peripheral-edge current supplying sections. 
     
     
         6 . The method of wafer plating claimed in  claim 1  wherein the anode electrode comprises from four to eight peripheral-edge current supplying sections. 
     
     
         7 . The method of wafer plating claimed in  claim 1  wherein 40% of the total plating current is supplied from the central current supplying section and 60% of the total plating current is supplied from the peripheral-edge current supplying sections. 
     
     
         8 . The method of wafer plating claimed in  claim 1  wherein the plating liquid comprises gold. 
     
     
         9 . The method of wafer plating claimed in  claim 1  wherein the anode electrode comprises a central current supplying terminal and four peripheral-edge current supplying terminals. 
     
     
         10 . The method of wafer plating claimed in  claim 1  wherein the anode electrode comprises a central current supplying terminal and six peripheral-edge current supplying terminals. 
     
     
         11 . The method of wafer plating claimed in  claim 1  wherein the cathode electrode is ring shaped and comprises four peripheral-edge current supplying terminals. 
     
     
         12 . The method of wafer plating claimed in  claim 1  wherein the cathode electrode is ring shaped and comprises seven peripheral-edge current supplying terminals.