Controlled Electrochemical Nanomachining with Adjustable Capacitance

In electrochemical micromachining using ultrashort pulses, pulse duration is the only effective parameter for controlling machining resolution. In this study, a controlled electrochemical micromachining technique was proposed. An adjustable capacitance element was included in an equivalent circuit of electrochemical micromachining to form a coupled fluid-electric circuit. The time constant of the coupled fluid-electric circuit depended on both local separation between electrodes and the adjustable capacitance. Therefore, the adjustable capacitance could be utilized as another control parameter of machining resolution. With an increase in the capacitance, a large polarization voltage can be easily confined to electrode regions in very close proximity. This technique was used for the local etching of some microstructures, and a nanoscale machining resolution was achieved.