A critical review of corrosion phenomena in microelectronic systems

In general corrosion is one of the most critical aspects for long term reliability. Most of the accelerated tests are not taken this aspect into account. Especially applications in the power electronics field imply some of the harshest environmental conditons for electrical components. To protect these systems typically polymers are being used for the packaging. This is not a hermetic sealing method, but it provides a sufficient housing for most of the applications being a small sized and very low cost package. Polymeric materials are prone to leakage and permeation of moisture and corrosive gases into package which could damage the dies, wires, bond pads, lead frames and solder joints. Therefore, corrosion is a long-term issue in microelectronic packages and is related to the whole system. This paper gives an overview of corrosion induced degradation of microelectronic packages and presents a measurement principle to characterize the protection efficiency of encapsulation layers by an electrochemical measuremnt.