Patent ID: 7857960

Claim:
A copper plating method comprising: a) activating an object to be plated with a pre-dip solution comprising acid and from 0.75 mg/l to 1000 mg/l of bromide ions, the object is of copper; b) contacting the object to be plated with a pre-treatment solution containing at least 0.75 mg/l of bromide ions; and c) precipitating a copper plate of 20 microns to 8 microns on the object by electrolytic copper plating using a copper plating solution containing copper ions, electrolytes, chloride ions and bromide ions, the chloride ions and the bromide ions are at concentrations to fulfill relationships of equations: (1) (Cl−30)/20<Br (130+Cl)/20, (2) 50−Cl<10×Br and (3) 10<Cl wherein Cl is chloride ion concentration in the copper plating solution in mg/l and Br is bromide ion concentration in the copper plating solution in mg/l.