Abstract: A wafer chuck assembly is provided. In one embodiment, the chuck assembly comprises a hub, a plurality of arms mounted to the hub and a plurality of holders. Each arm extends outwardly from the hub, and each arm has a proximal end adjacent the hub and a distal end remote from the hub. Each holder is mounted at the distal end of each respective arm, and each holder has a plurality of support pins configured to support a wafer.

Abstract: An apparatus and a method for plating a substrate are provided. The apparatus includes: an electroplating cell for containing an electroplating solution; a substrate holder for holding a substrate in the electroplating solution; a rotation driver coupled to the substrate holder and configured to rotate the substrate holder; a power distribution assembly coupled to the rotation driver; an anode disposed within the electroplating cell; a power supply unit electrically coupled between the anode and the power distribution assembly, thereby forming an electric loop; and a current regulating member for providing a predetermined impedance value for the electric loop, wherein a voltage provided by the power supply unit causes an electric current to flow through the electric loop, and the predetermined impedance is such selected that the variation of the electric current is kept within a smaller range compared to that measured in the absence of the current regulating member.