Patent ID: 7169705

Claim:
A method of plating a film onto a substrate, comprising: positioning an electric resistor between a conductive layer, formed on at least a portion of a surface of a substrate, and an anode; introducing respectively a plating solution into a space between said conductive layer and said anode on a conductive layer side of said space, and an anode solution into said space between said conductive layer and said anode on an anode side of said space, thereby filling said space with a plating bath composed of said plating solution and said anode solution, with said plating solution containing 25 to 75 g/L of copper ions and at least 0.4 mole/L of an organic acid or an inorganic acid, and said anode solution being of the same composition as said plating solution, or containing 0 to 75 g/L of copper ions and at most 0.6 mole/L of an organic acid or an inorganic acid; applying a voltage between said conductive layer and said anode to plate a surface of said conductive layer; measuring electric conductivity of said anode solution; and adding at least pure water, an organic acid, or an inorganic acid to said anode solution to keep the electric conductivity of said anode solution at a constant level of at most 200 mS/cm when said surface of said conductive layer starts being plated.