In order to improve the adhesion between Parylene C and gold, Parylene C was surface-treated using ion-assisted reaction (LAR) before depositing gold at a working pressure of 0.6 mPa. Ar ion irradiation was performed under oxygen gas at a vacuum of 13 mpa. The contact angle of surface-treated Parylene C film on Si decreased significantly and the surface energy increased compared to untreated Parylene C film. These results are attributed to the presence of hydrophilic groups on the Parylene C films surface after modification using LAR These functional groups were confirmed by X-ray photoelectron spectroscopy analysis on the modified Parylene C film. We confirmed that the adhesion of evaporated gold film on Parylene C improved as a function of ion dose quantities. (c) 2004 Elsevier B.V. All rights reserved.