Plating method

Abstract

A method of plating a substrate, such as a wafer, by applying a voltage between the substrate and an anode is disclosed. The plating method includes: preparing a substrate having a recess formed in a surface thereof, a conductive layer being formed in at least a part of the recess; placing an insoluble anode and the substrate in contact with a copper sulfate plating solution containing an additive; applying a predetermined plating voltage between the substrate and the insoluble anode by a plating power source to plate the substrate; and shutting off a reverse electric current, which flows from the insoluble anode to the substrate via the plating power source, by a diode disposed between the insoluble anode and the substrate when the predetermined plating voltage is not applied.

What is claimed is: 
     
         1 . A method for plating a substrate while preventing a generation of an electrolyte component which inhibits bottom-up plating of the substrate, comprising:
 preparing a substrate having a recess formed in a surface thereof, a conductive layer being formed in at least a part of the recess;   placing an insoluble anode and the substrate in contact with a copper sulfate plating solution containing an additive;   applying a predetermined plating voltage between the substrate and the insoluble anode by a plating power source to plate the substrate; and   applying a forward voltage, which is lower than the predetermined plating voltage, between the substrate and the insoluble anode when the predetermined plating voltage is not applied, thereby decreasing a reverse electric current which flows from the insoluble anode to the substrate via the plating power source.   
     
     
         2 . The method according to  claim 1 , wherein the forward voltage is applied by the plating power source. 
     
     
         3 . The method according to  claim 1 , wherein the forward voltage is applied by an auxiliary power source which is coupled in parallel with the plating power source. 
     
     
         4 . The method according to  claim 1 , wherein an inert gas is supplied into the copper sulfate plating solution while applying the forward voltage between the substrate and the insoluble anode, thereby lowering a concentration of dissolved oxygen in the copper sulfate plating solution. 
     
     
         5 . The method according to  claim 1 , wherein the copper sulfate plating solution is passed through a deaerator while applying the forward voltage between the substrate and the insoluble anode, thereby lowering a concentration of dissolved oxygen in the copper sulfate plating solution.