| 초록 |
Despite the appealing technical advantages of printed electronic (PE) technologies, there are very few studies on the technical maturity of PEs. Conductive materials are used as the primary material used in PEs; therefore, EM is an important reliability aspect of printed conductive patterns. EM has been identified as a primary failure mode of interconnect lines used in semiconductor-integrated circuits. EM is a high-current density induced mass transport phenomenon exhibiting itself as voids, hillocks, and/or open circuits, due to a momentum exchange between conduction electrons and host metal atoms. High values of temperature and current density accelerate the damage, causing an increase in the lines resistance and circuit lifetime reduction. In this study, we investigated the EM characteristics with different EM test vehicles and Ag interconnected lines printed by an electrohydrodynamic (EHD)-jet-printing technique. It was found that Ag ions are migrated towards the cathode in Ag interconnected line and void formation at the anode. The microstructure of the printed lines after electromigration test was observed by Field emission scanning electron microscopy (FESEM). The activation energy for EHD-jet-printing Ag interconnected lines was measured by Arrhenius-type plot from resistance measurements. Statistical analysis of the mean-time-to-failure of the printed lines provided the activation energy and current density exponent of Black’s equation, which is used to estimate the lifetime of the printed line under the conditions of use (current density and operation temperature). The activation energy obtained from the statistical analysis indicated that the EM failure in the EHD-jet-printed Ag interconnect lines were mainly driven by the surface diffusion. We tried to infiltrate polyimide (PI) into the EHD-jet-printed Ag interconnect lines to suppress the surface diffusion of ions. It is observed that the activation energy increased with PI infiltration into the EHD-jet-printed Ag interconnect lines. |
