Characterization of a silicone gel as a coating use for corrosion protection

The authors report on failure mechanisms and microstructure characterization of silicon gel as a protective coating on integrated circuits. The corrosive effects of water in permeating the sealing layer, penetrating, and forming voids in the gel were observed. The relation of protection reliability to gel cure temperature was analyzed using infrared absorption spectra, a mass spectrum analyzer, and scanning electron microscopy. It is concluded that penetrating water removes gel through vaporization due to a temperature gradient, and that insufficiently cured gel contains relatively large holes that allow water penetration rather than only trapping gas molecules as small holes in the properly cured gel.<>