In-Line Resistance and Temperature Measurement of Conductive Inks

The necessary metal-based inks typically consist of silver nanoparticles dispersed in a liquid carrier medium. In order to keep the ink stable and printable, the agglomeration and sedimentation of these functional components need to be prevented as long as they are not printed onto a substrate. This is typically done by the addition of organic (usually polymeric) stabilizers that induce repulsion between the metal nanoparticles. Process optimization involves the screening of a wide range of materials, temperatures, and sintering times and typically the resulting resistance is measured only at the end of the process. The measuring probe consists of an evaporated metal line that is covered with a thin isolating layer. In order to prevent direct electrical contact between the probe line and the conductive ink to be tested, the probe line is covered by an insulating layer.