Electropulsing Treatment on Enhancement of Electrical Conductivity of Screen-Printed Ag Wire

The effect of high electric current density on the sintering of Ag wires manufactured by screen printing is evaluated through electrical resistivity analysis and microstructure observation. Different forms (continuous and pulsed) of electric current with different current densities are applied to the specimens. Conventional heat treatment is also performed as a control group to examine the athermal effect of electropulsing treatment. Compared to the conventional heat treatment, the resistivity is reduced more under the electropulsing treatment with continuous current for the same temperature and treatment time. Also, the process time of electropulsing treatment can be reduced by applying a pulse form of high density current instead of continuous current without losing the benefit of enhanced reduction of resistivity. The microstructural observations obtained from high angle annular dark field scanning transmission electron microscope and a digital precession instrument clearly show that necking connecting the crystals is formed more firmly under electric current. In addition, the temperature change of Ag wire and substrate is calculated according to the change of the resistivity when the electric current is applied to confirm the reliability.