Thermal influence on excimer-laser-induced electrical conductivity on polyimide film surfaces

The thermal influence on the electrical conductivity of polyimide film surf aces induced by KrF-laser irradiation was investigated, The formation of co nducting phases was demonstrated to be highly temperature sensitive, as evi denced by strong dependence of the electrical conductivity on repetition ra te and ambient temperature. XPS and Raman studies showed that the efficienc y of the formation of conducting phases could be enhanced by the increase o f temperature on irradiated polyimide film surfaces. After the disruption o f polymeric chain, the carbon-enriched clusters remained on the irradiated polyimide film surfaces organized into polycrystalline graphite-like cluste rs responsible for electrical conductivity. The resulting dangling bonds fr om the decomposition process of polyimide acted as centers for the rearrang ement of carbon-enriched clusters. It is suggested that the motion of radic als was promoted with increasing the temperature. Therefore the formation o f polycrystalline graphite-like clusters benefited from high remaining temp erature on the irradiated polyimide film surfaces. These results revealed t hat thermal influence played a dominant role on the formation of conducting phases.