Isothermal solidification based packaging of biosensors at low temperatures

Thick film Au printed square contact pads are interconnected to Cu substrates at constant pressure and temperature using the isothermal solidification of Bi–In alloy on the joining surfaces. The effect of reaction time on the mechanical strength of the package has been analyzed. Thermal stability of the fabricated specimens have been measured and discussed. The delaminated surfaces examined optically reveal the morphology of the metallization zones on the joining substrates. The scanning electron microscopy of these surfaces is reported in this paper. Tests for thermal shock, pH resistivity and shelf life have been carried out to predict the reliability of the packaging for long term applications.