Atmospheric-Pressure Plasma Sintering of Silver Nanopaste Screen-Printed on PI

As an alternative sintering method for conductive circuits on polymeric substrates, atmospheric-pressure plasma (APP) sintering is suggested because it is possible to be employed in air at room temperature. The conductive patterns were constructed via screen printing by using silver (Ag) nanopaste. The microstructure and electrical resistivity of the Ag printed patterns were investigated with a field emission scanning electron microscope (FE-SEM) and a 4-point probe station, respectively. For redox reaction, argon (Ar) oxygen (O-2), and hydrogen (H-2) gases were used in APP sintering. The experimental results showed that the selective sintering of Ag nanopaste was achievable by APP without affecting a polyimide (PI) substrate. The electrical resistivity of Ag pattern sintered for 20 min was achieved one order of magnitude (31.3 mu Omega.cm) higher than that of bulk Ag. When the APP sintering time increased, the Ag patterns showed lower electrical resistivity and higher apparent density.