Plating apparatus and plating method

Abstract

Provided are a plating apparatus and a plating method for preventing or mitigating electric field diversion irrespective of the physical or mechanical structure. According to one embodiment, provided is a plating apparatus comprising: a substrate holder configured so as to hold a substrate; a plating bath configured so as to accommodate the substrate holder which holds the substrate, and provided with a first tank on a first surface side of the substrate and a second tank on a second surface side of the substrate, the first tank and the second tank communicating with each other with a gap therebetween; a first anode electrode arranged in the first tank of the plating bath; a first power source configured so as to supply a plating current between the substrate and the first anode electrode; an auxiliary anode electrode arranged on the first tank side of the gap; an auxiliary cathode electrode arranged on the second tank side of the gap; and an auxiliary power source configured so as to supply an auxiliary current between the auxiliary anode electrode and the auxiliary cathode electrode.

1 . A plating apparatus comprising:
 a substrate holder constructed to hold a substrate;   a plating tank constructed to allow the substrate holder holding the substrate to be put in the inside thereof, and comprising a first tank positioned on the side of a first surface of the substrate and a second tank positioned on the side of a second surface of the substrate, wherein the first tank and the second tank communicate with each other via a gap;   a first anode electrode arranged in the first tank in the plating tank;   a first electric power source constructed to supply plating current between the substrate and the first anode electrode;   an auxiliary anode electrode arranged in a position that is in the gap and on the side of the first tank;   an auxiliary cathode electrode arranged in a position that is in the gap and on the side of the second tank; and   an auxiliary electric power source constructed to supply auxiliary current between the auxiliary anode electrode and the auxiliary cathode electrode.   
     
     
         2 . The plating apparatus according to  claim 1 , wherein the auxiliary current is set to have a current value that is obtained by dividing an over-voltage in the first surface of the substrate by a resistance value of electrolytic solution that exists between the auxiliary anode electrode and the auxiliary cathode electrode. 
     
     
         3 . The plating apparatus according to  claim 1  further comprising:
 a second anode electrode arranged in the second tank in the plating tank; and 
 a second electric power source constructed to supply plating current between the substrate and the second anode electrode, wherein current outputted from the second electric power source is set in such a manner that an over-voltage in the second surface of the substrate is smaller than an over-voltage in the first surface of the substrate. 
 
     
     
         4 . The plating apparatus according to  claim 3 , wherein the auxiliary current is set to have a current value that is obtained by dividing a difference between the over-voltage in the first surface of the substrate and the over-voltage in the second surface of the substrate by a resistance value of electrolytic solution that exists between the auxiliary anode electrode and the auxiliary cathode electrode. 
     
     
         5 . The plating apparatus according to  claim 4  further comprising:
 a first reference electrode, which is arranged in a position close to the first surface of the substrate, for measuring an over-voltage in the first surface of the substrate, and 
 a second reference electrode, which is arranged in a position close to the second surface of the substrate, for measuring an over-voltage in the second surface of the substrate; wherein 
 the auxiliary current is controlled based on an over-voltage measured by using the first reference electrode and an over-voltage measured by using the second reference electrode. 
 
     
     
         6 . The plating apparatus according to  claim 4 , wherein the auxiliary current is controlled based on a measured value of current supplied from the first electric power source and a measured value of current supplied from the second electric power source. 
     
     
         7 . The plating apparatus according to  claim 6 , wherein the auxiliary current is controlled based on a difference between current density in the first surface of the substrate and current density in the second surface of the substrate. 
     
     
         8 . The plating apparatus according to any one of  claim 7  comprising barrier membranes arranged in a position between the auxiliary anode electrode and the first tank in the plating tank and a position between the auxiliary cathode electrode and the second tank in the plating tank, and constructed to allow selective permeation of ions. 
     
     
         9 . The plating apparatus according to any one of  claim 8 , wherein the gap makes the first tank and the second tank communicate with each other by a bent path. 
     
     
         10 . The plating apparatus according to any one of  claim 9 , wherein the substrate is that in which the first surface and the second surface are electrically conducted to each other. 
     
     
         11 . A method for plating a substrate by a plating apparatus, wherein the plating apparatus comprises
 a substrate holder constructed to hold a substrate, and   a plating tank constructed to allow the substrate holder holding the substrate to be put in the inside thereof, and comprising a first tank positioned on the side of a first surface of the substrate and a second tank positioned on the side of a second surface of the substrate, wherein the first tank and the second tank communicate with each other via a gap; and the method comprises:   supplying, from a first electric power source, plating current between a first anode electrode, which is arranged in the first tank in the plating tank, and the substrate; and   supplying, from an auxiliary electric power source, auxiliary current between an auxiliary anode electrode, which is arranged in a position that is in the gap and on the side of the first tank, and an auxiliary cathode electrode, which is arranged in a position that is in the gap and on the side of the second tank.