Stepwise current electrical sintering method for inkjet-printed conductive ink

An innovative electrical current sintering technique is applied to joule-heat conductive ink by increasing current gradually through a stepwise-form. This stepwise electrical sintering technique is devised to overcome thermal damage of printed conductive ink line during electrical sintering due to its high initial resistance. To monitor a stepwise electrical sintering method, in-situ specific resistance was measured. Surface morphology of the sample was observed by field-emission scanning electron microscope. By increasing the current gradually, the conductive line can endure higher current because the specific resistance has dropped gradually during the process. Finally, enhanced final-step current produces lower specific resistance of the conductive line than that obtained from a constant current-supplying electrical sintering method without damaging printed conductive line. (C) 2014 The Japan Society of Applied Physics