Package characterization of FET-based biochemical sensors

In this study we present packaging techniques for SD-card form factor test adapters. Our test adapters consist of FET-based biochemical sensors and a CMOS integrated analog multiplexer connected to a printed circuit board (PCB). Protection of the test adapter is required for long term stability and reliable measurements of the biochemical sensor in a liquid environment. Two different encapsulation techniques and biocompatible materials with different thermo-mechanical properties were used for this purpose. Adhesive strength measurements of these encapsulants on different substrates were carried out. Finally, the package was integrated into a portable measurement system for multiplexed measurements. Measured gate characteristics were compared between blank and packaged test adapters. FET characteristics were measured in dry as well as in liquid environment. Our packaging technique is mechanically stable, suitable for measurements in liquid environments influences neither the electrical characteristics of the FET devices as nor data acquisition.