An etchingcleaning apparatus is provided, which makes it possible to effectively remove an unnecessary material or materials existing on a semiconductor wafer without damaging the device area with good controllability. The power cable comprises an insulated line wire and an insulated neutral wire with a conductive shield surrounding the line wire and the neutral wire. A volatile MOS transistor, an inverter, or a buffer may be driven by coupling its gate or input to the common connection between the non-volatile MOS transistor and the volatile MOS transistor.