Surface analysis of gold containing polyimide films

Abstract

Polyimide films with metallic surfaces were produced by thermal treatment of solutions containing HAuCl4⋅3H2O, hydrogen tetrachloroaurate trihydrate, and either Ciba–Geigy XU 218, poly[5(6)-amino-1-(4′ phenyl)-1,3,3 trimethylindane-3,3′,4,4′-benzophenonetetracarboxylimide] or BTDA-ODA, poly [ p, p′-oxybis (phenylene)-3,3′,4,4′-benzophenonetetracarboxylimide]. Scanning electron microscopy indicated that 0.1-μ particles covered a large portion of the air side surface; whereas, 10-μ particles covered the glass side surface of these films. Auger electron spectroscopy and x-ray photoelectron spectroscopy (XPS) indicated that the particles were gold in the metallic state. Model imide compounds were synthesized and used to evaluate the XPS spectra of both unmodified and gold containing films. Surface analysis data suggested that only a small amount of gold was located within the XPS sampling depth and that the observed gold particles resided underneath a polyimide overlayer. The discrete metal particles had an unexpected influence on the photoelectron spectra of the polyimide and the influence was dependent on particle size. A schematic model of the multilayered modified film surface was developed and the model further probed by electron flood gun and metal vapor deposition studies.