Apparatus and method for processing a substrate

Abstract

A method and apparatus are set forth capable of processing a substrate with a high uniformity within the surface area even for a thin feeding layer. The method comprises arranging a counter electrode and the substrate to confront each other; providing a membrane between the counter electrode and the substrate to define a substrate side region and a counter electrode side region. The substrate side region and the counter electrode side region are capable of accommodating respective electrolytes. The substrate side region and the counter electrode side region are supplied with respective electrolytes having different specific resistances. A processing current is also supplied between the substrate and the counter electrode.

1 . A method for processing a substrate comprising:
 arranging a counter electrode and said substrate to confront each other;   providing a membrane between said counter electrode and said substrate to define a substrate side region and a counter electrode side region, said substrate side region and said counter electrode side region capable of accommodating respective electrolytes;   supplying said substrate side region and said counter electrode side region with respective electrolytes having different specific resistances; and   supplying a processing current between said substrate and said counter electrode.   
   
   
       2 . The method of  claim 1 , wherein said membrane comprises at least one of a porous membrane, a porous structural member, and an ion exchange membrane. 
   
   
       3 . The method of  claim 1 , wherein said substrate is formed with fine interconnect recesses for receiving a metal material through plating, and a feeder layer for feeding said substrate with a plating current, said fine interconnect recesses having a width not more than 0.3 μm and said feeder layer having a thickness not more than 0.05 μm. 
   
   
       4 . The method of  claim 3 , wherein said substrate is set as an anode, and said counter electrode is set as a cathode to electroplate copper to said substrate, and wherein said electrolyte supplied to said counter electrode side region has a larger specific resistance than said electrolyte supplied to said substrate side region. 
   
   
       5 . The method of  claim 4 , wherein said electrolyte supplied to said counter electrode side region is a copper free electrolyte solution. 
   
   
       6 . The method of  claim 1 , wherein said counter electrode comprises an insoluble material. 
   
   
       7 . An apparatus for processing a substrate comprising:
 a vessel for accommodating said substrate;   a counter electrode arranged to confront said substrate;   a membrane arranged between said counter electrode and said substrate to define a substrate side region and a counter electrode side region, said substrate side region and said counter electrode side region capable of accommodating respective electrolytes;   electrolyte supply systems for respectively supplying said substrate side region and said counter electrode side region with respective electrolytes having different specific resistances; and   a power source for supplying a processing current between said substrate and said counter electrode.   
   
   
       8 . The apparatus of  claim 7 , wherein said membrane comprises at least one of a porous membrane, a porous structural member, and an ion exchange membrane. 
   
   
       9 . The apparatus of  claim 7 , wherein said electrolyte supply system for supplying said electrolyte to said counter electrode side region comprises a specific resistance detector for detecting specific resistance of electrolyte and a specific resistance adjuster for adjusting specific resistance of electrolyte based on an output of said specific resistance detector. 
   
   
       10 . The apparatus of  claim 7 , wherein said substrate is set as a cathode, and wherein said counter electrode is set as an anode, and wherein said counter electrode comprises a mesh-like member made of an insoluble material. 
   
   
       11 . The apparatus of  claim 10 , further comprising a gas discharge line for discharging a gas generated at said anode.