A gel-based wafer-level testing procedure for microelectrodes

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