A percolative approach to investigate electromigration failure in printed Ag structures

Abstract

The ease of fabrication and wide application of printed microelectronics are driving advances in reactive inks. The long-term performance of structures printed using reactive ink is important for their application in microelectronics. In this study, silver lines are printed with low-temperature, self-reducing, silver-diamine based ink. The electromigration failure of the printed silver is first studied using Black's equation. However, due to the porous nature of the printed Ag line, Black's equation is not the best fit for predicting the lifetime, this is because Black's equation does not take into account morphology-induced current crowding. We find that the resistivity of the printed Ag lines can be described (as a function of void fraction) by percolation theory. In addition, we also demonstrate that the failure lifetimes of the printed Ag can be predicted quite well by a percolative model of failure.