Apparatus and method for improving uniformity in electroplating

Abstract

A method and apparatus for plating a metal onto a substrate. One embodiment of the present invention provides an apparatus for electroplating a substrate. The apparatus comprises a fluid basin, an anode disposed near a bottom of the fluid basin, a restrictor disposed above the anode, and a substrate support member configured to move the substrate within the fluid basin among different elevations relative to the restrictor. Plating profiles on the substrate may be adjusted by changing the elevation of the substrate during plating.

1 . A method for plating a metal onto a substrate, comprising:
 applying a plating bias to the substrate while moving the substrate in a plating solution to adjust the plating current distribution across the substrate.   
     
     
         2 . The method of  claim 1 , further comprising:
 providing a plating cell having in a fluid volume to retain the plating solution therein, wherein the fluid volume has a restricted section having a smaller sectional area than a plating surface on the substrate;   providing an anode on one side of the restrict section; and   positioning the substrate in a first position, wherein the substrate and the anode are on opposite sides of the restricted section; and   applying a first waveform between the substrate and the anode.   
     
     
         3 . The method of  claim 2 , wherein the applying the plating bias to the substrate while moving the substrate further comprising:
 moving the substrate to a second position to adjust a distance between the substrate and the restricted section; and   applying a second waveform between the substrate and the anode.   
     
     
         4 . The method of  claim 3 , wherein the second position is further away from the restricted section than the first position. 
     
     
         5 . The method of  claim 2 , wherein the anode having an upper surface smaller than the plating surface of the substrate, and the restricted section is formed by the upper surface of the anode. 
     
     
         6 . The method of  claim 2 , wherein the restricted section is formed by a shield having an inner diameter smaller than the diameter of the substrate. 
     
     
         7 . The method of  claim 2 , further comprising:
 providing an auxiliary anode disposed approximate the restricted section; and   applying an electric bias to the auxiliary anode.   
     
     
         8 . The method of  claim 7 , further comprising:
 providing a protective tube to encase the auxiliary anode, wherein the protective tube comprising an ionic membrane; and   supplying an electrolyte to the protective tube.