CF4/O2 PLASMA-ETCHING AND SURFACE MODIFICATION OF POLYIMIDE FILMS - TIME-DEPENDENT SURFACE FLUORINATION AND FLUORINATION MODEL

The interaction of CF4/02plasma mixtures with polyimide pyromellitic dianhydride-oxydianiline (PMDA-ODA) films is a complex process. In this investigation, the reactions of PMDA-ODA with a gas mixture containing 90% CF4/10% O2, as a function of treatment time, are studied with x-ray photoelectron spectroscopy (XPS). Curve fitting of the resulting spectra yields the distribution of CFxspecies formed during reaction. A detailed reaction mechanism of F atom addition to PMDA-ODA is constructed on a simplified monomer unit. The experimental results fitted to the proposed model yield apparent reaction rate constants and the time dependent concentration of unstable surface species in the reaction zone. © 1990, American Vacuum Society. All rights reserved.