A novel prebonding plasma surface activation methed has been introduced. Surface silicon dangling bonds are significantly increased after surface activation which lead to effectively chemical adsorption of OH groups. Plasma produced by low pressure gas electric discharges can give energy to and activate the surface by ion bombardment. Therefore

activation effectiveness is independent of the gas used. Temperature can give energy to and passi-vate the oxide surface through thermal energy. Therfore

the activation temperature should not be over a critical point. Plasma treatment at 850℃ for 6’ provides satisfactory results. 3" silicon wafers were succesfully bonded with this method. High voltage and 0.8-3μm CMOS devices have shown that the bonding introduces no contamination and extra stress

thus guarantee the bonding quality.