A cavitation assembly for purification of drinking water includes a generally cylindrically-shaped open-ended tube for flow of water therethrough, the tube comprising a transducer for converting electrical energy to acoustic energy and transmitting ultrasound through the water in the tube to induce cavitation in the water in the tube. The system has a server, a transceiver and an RFID tag. The method can be applied to the fabrication of semiconductor devices for increasing the removal rate of the photoresist layer. The clock divider receives the PLL output clock and generates a first output clock.