Effect of heat treatment on physical and electrical characteristics of conductive circuits printed on Si substrate

Printed electronics is expected to increase its market share significantly in near future on account of its high material usage efficiency, environmental friendliness, the avoidness of expensive process steps, and the ability to rapidly change circuit designs in real time in a highly cost effective fashion. Herein, we tried to examine the physical characteristics of the two types of selected Ag nanopastes and electrical characteristics of screen printed Ag patterns on a Si substrate sintered at 200 °C for varying sintering times. The first type of the paste had no binder material and the second one was formulated with an addition of a polymeric binder. They had different thermal behaviors, i.e., the paste with a binder showed a continuous small reaction well beyond the temperature for the main reaction of the paste without any binder. The microstructure of the Ag tracks after sintering was also different between the two cases, which verified the poor electrical characteristics of the paste containing a binder than the one without any binder. We also measured the insertion losses of the Ag tracks with a design for the high frequency transmission, and the observed electrical behaviors were discussed with the physical properties of the pastes measured in this study.