Method and apparatus for cleaning semiconductor wafers with a deionized water solution containing a gas at saturated concentration, with temperature controlled degasification and megasonic agitation

摘要

A system is provided to prepare deionized water having a 100% saturated concentration of a gas, e.g., nitrogen, at a hot temperature, e.g., 50-85°C, and an attendant pressure, e.g., atmospheric pressure, to clean a semiconductor wafer, e.g., of silicon. The gas concentration of deionized water having a predetermined concentration of the gas at a cold temperature, e.g., 15-30°C, is adjusted in a degassifier chamber having a vacuum pump and a pressure sensor, to provide an under-saturated concentration of the gas at the cold temperature corresponding to the saturated concentration thereof at the hot temperature and attendant pressure. The adjusted gas concentration water is then heated in a heating vessel having a heater and a temperature sensor, to the hot temperature to form a hot bath having such saturated gas concentration to clean the wafer, e.g., in a cleaning tank under megasonic vibrations. A controller is connected to the pump, pressure sensor, heater and temperature sensor to control the chamber pressure and vessel temperature.