In transistors, integrated circuits production, water is mainly used for cleaning silicon wafers, while a small amount of liquid used in the preparation, the water vapor sources of silicon oxide, some of the equipment cooling water, the preparation of plating solution and so on. IC 80% of the production process of the process requires the use of ultra pure water cleaning silicon wafers, the water quality and the IC product quality and production yield great deal. Water, alkali metal (K, Na, etc.) will withstand adverse insulating film, heavy metals (Au, Ag, Cu, etc.) will reduce the PN junction voltage, Ⅲ group elements (B, Al, Ga, etc.) make the N-type Deterioration of semiconductor properties, Ⅴ group elements (P, As, Sb, etc.) make the P-type semiconductor properties of deterioration, bacteria in water temperature carbonization of phosphorus (about 20 ~ 50% ash) would P-type silicon on the local area change N-type silicon as a result of deterioration of device performance, the water particles (including bacteria) such as adsorption on silicon surfaces, can cause a short circuit or characteristics worse. IC production requirements on water quality in Table 2.
 Table 2 integrated circuit (DRAM) water quality requirements of ultra-pure water