Growth kinetics of interfacial damage: epoxy coating on a generic dual inline package

Epoxy coated dual inline packages (DIPs) consisting of 24 pins and three parallel gold metallization lines were used as test vehicles in accelerated environmental tests. The coated DIPs were subjected to 121/spl deg/C, 100% relative humidity, and unbiased conditions as a standard test condition. After each test, optical microscopy was performed to monitor the interfacial damage. Changes in the leakage current also were monitored for correlation with measured interfacial damage. The growth of interfacial damage as a function of time was observed over the entire surface area of each DTP. Each damage site on the interface was monitored in an effort to model the evolution of the geometrical features and magnitude of the damage. It was noted that a two-parameter Frechet cumulative distribution function (cdf) could be used to represent the damage growth at each time interval. Precipitate in typical damage locations also was analyzed and found to consist primarily of sodium, carbon, and oxygen. The growth kinetics of interfacial damage, including the location and magnitude of the damage, is characterized, and the dominant failure modes are identified for this type of protective coating.