The bonding of polyimide precursors to Ni studied by electron energy loss spectroscopy

Abstract

Polyimides have considerable technological importance in the microelectronics device industry on account of their thermal stability and dielectric properties. The interface between metals and polyimides has been studied most frequently by metal evaporation onto the preformed bulk polyimide. Recently, the microscopic nature of the interface has been probed, by XPS, following vacuum deposition of the precursors to the polyimide on copper and gold surfaces. The authors report preliminary high resolution electron energy loss spectra (HREELS) of the precursors, m-phenylenediamine (m-PDA) and pyromellitic dianhydride (PMDA), which are vacuum deposited in situ onto a clean Ni(110) surface. Information concerning the nature of the adsorbed species and its orientation at the surface has been deduced. In particular, the dicarboxylic anhydride (PMDA) seems to interact via the C=O bonds of the molecule and the authors compare this behaviour to that of acetic anhydride adsorbed on the same Ni(110) surface.