Patent ID: 7850836

Claim:
A method of electro-depositing a conductive material in at least one through-hole via of a semiconductor substrate, said through-hole via having an effective aspect ratio, said method comprising: supplying an initial pulse current cycle to the via, said pulse current cycle comprising: a forward pulse current, and a reverse pulse current, wherein the forward pulse current and the reverse pulse current are each of a predetermined distinct magnitude and are each supplied over a predetermined distinct period, wherein the magnitude of the forward pulse current is lower than the magnitude of the reverse pulse current, such that a corresponding forward and reverse pulse current density is generated across the via causing conductive material to be deposited within the via, thereby reducing the effective aspect ratio of said via; measuring a remaining unfilled depth of the via after the initial pulse current cycle to determine the reduced effective aspect ratio of the via; supplying a first subsequent pulse current cycle to the via wherein the magnitude of the forward and reverse pulse currents of the first subsequent pulse current cycle are varied in relation to the reduced effective aspect ratio; measuring the remaining unfilled depth of the via after the first subsequent pulse current cycle to determine the further reduced effective aspect ration of the via; and supplying a second subsequent pulse current cycle to the via, wherein the magnitude of the forward and reverse pulse currents of the second subsequent pulse current cycle are varied in relation to the further reduced effective aspect ratio.