Processing of conductive polyimide using radiations

Abstract

PMDA-ODA polyimide is shown to become electrically conducting and optically absorbant on exposure to the 488 nm radiation of an argon ion laser or irradiation with 100 keV Ne + ions. Electron photoelectron spectroscopy has been used to study the chemical modification and structure of the conducting phase induced by irradiation. The ESCA spectrum of the Ne +-irradiated film indicates drastic loss of oxygen and nitrogen resulting in a modified structure. The C 1s spectrum shows these modifications with decarbonylation of the imide group (peak at 288.4 eV) and decrease of the component assigned to carbon in the PMDA ring or carbons bonded to nitrogen or oxygen (285.6 eV), whereas the main C 1s component (284.6 eV) is attributed to graphitic carbon. The plasmon observed at 7.8 eV in the UPS spectrum confirms the graphite-like electronic structure of the treated polyimide. Optical and electrical properties are interpreted by the formation of graphite-like inclusions dispersed in a dielectric matrix. Potential applications in the field of interconnection are discussed.