A plating apparatus and method for deposition of a conductive material on a semiconductor wafer having surface portions and cavity portions. A differential in an adsorbed concentration of an additive, including accelerators or suppressors, between a surface portion and a cavity portion of a wafer surface is established in a chamber. A mask or sweeper may be used to establish the differential. After establishing the differential in the chamber, the conductive material is electrodeposited to form a conductive layer on the surface in another chamber.