UV light-induced deposition of low dielectric constant organic polymer for interlayer dielectrics

The photo-induced conversion of polyamic acid spun onto Si and quartz substrates into thin polyimide films at low temperature using 172 nm radiation from a Xe-2* excimer lamp is described. The degree of imidization of the polyimide films during the UV curing at different exposure times and temperatures was investigated using Fourier transform infrared spectroscopy. Compared with conventional furnace processing, the photo-induced curing of the polyimide provided both reduced processing time and temperature. Ellipsometry, UV spectrophotometry. capacitance-voltage and current-voltage measurements were employed to characterize the polymer films and indicated them to be of high quality. In particular, the current-voltage measurements showed that the leakage current density of the irradiated polymer was over an order of magnitude smaller than has been obtained in layers prepared by thermal processing. (C) 1998 Elsevier Science B.V.