Abstract: A method is provided for subtractively processing a layer of etchable material formed over an electrically conductive surface region of a workpiece. The workpiece is immersed in a liquid solution, generally but not exclusively a conductive solution, that comprises an etchant for the etchable material, so that etching of the etchable material is initiated. An electric circuit is connected to include a control electrode, a reference electrode, and the electrically conductive surface region of the workpiece. The electric circuit is used to monitor the development process dynamically at each of a plurality of intervals during the etching. The etching is terminated when the electrochemical signal satisfies a criterion indicating that the etching is complete.

Abstract: A plurality of through holes in a workpiece are filled with a solid conductive material. The workpiece is immersed in an electroplating solution, with the through holes covered at one end by a portion of a conductive plating base. The electroplating solution is permitted to fill the through holes in the workpiece and contact the portion of the conductive plating base. A voltage applied to the conductive plating base enables an electroplating operation that deposits the solid conductive material on the portion of the conductive plating base to thereby fill the through holes with the solid conductive material.