A testing procedure at wafer level for micro electrodes using a gel

We demonstrate a novel 3-point impedance measurement procedure for microelectrodes. The concept is based on the use of a saline gel and enables relatively fast measurement at wafer level. In this study, measurements were first carried out with a saline gel as electrolyte, and then compared to a reference measurement with a conventional saline solution as electrolyte. The impedance as function of frequency was investigated for two different electrode sizes, and showed good agreement between both electrolytes. The testing procedure described in this paper can be applied to e.g. biomedical microsystems that must interact with a wet environment.