Patent ID: 8603305

Claim:
An apparatus for electroplating onto substrates, comprising: (a) a separated anode chamber for containing electrolyte and an anode; (b) a cathode chamber for receiving substrates and contacting them with a catholyte; (c) a separation structure positioned therebetween, said separation structure comprising a transport barrier which enables passage of ionic species across the transport barrier while maintaining different electrolyte compositions in the anode chamber and the cathode chamber; and (d) an open loop recirculation system for providing electrolyte to and removing electrolyte from the separated anode chamber during electroplating, wherein the open loop recirculation system is configured to expose the electrolyte to atmospheric pressure and comprises a pressure regulating device arranged to maintain the electrolyte in the anode chamber at a substantially constant pressure, and wherein the pressure regulating device is designed or configured to compensate for depletion of electrolyte in the separated anode chamber resulting from an electroosmotic effect.