Ｔhe pattern of ITO transparent electrode of pixel cells in TFTAMLCD is a critical step in the manufacturing process of flat panel display devices,the development of suitable plasma reactive ion etching is necessary to achieve high resolution display.In this work we investigated the Ar/CF4 plasma etching of ITO as function of different parameters.We demonstrated the ability of this plasma to etch ITO and achieved an etching rate of about 3.73nm/min,which is expected to increase for long pumping down period,and also through addition of hydrogen in the plasma.Furthermore we described the ITO etching mechanism in Ar/CF4 plasma.The investigation of selectivity showed to be very low over silicon nitride and silicon dioxide but very high over aluminum.