ABSTRACT
Electronic packages can be affected by many environments, including temperature, vibration, altitude, and humidity. The relative humidity is the ratio of the partial pressure of water vapor in the air to the pressure of saturated water vapor at the temperature of the air. Moisture-induced wire bond damage is commonly found in temperature cycling, temperature and humidity cycling, and pressure cooker tests. Early detection and correction of leaks in hermetic packages will keep potential corrosion-related defects from becoming reliability problems. Corrosion can occur during manufacturing, storage, shipping, and service. Failure of electronic equipment due to corrosion is dependent on the package type, corroding material, fabrication and assembly processes, and environmental conditions. Galvanic corrosion occurs when dissimilar metal structures, such as molybdenum-gold metallization or the aluminum metallization-gold bond wire interface, are subjected to corroding environments. The conductivity of the corrosion medium will affect both the rate and the distribution of galvanic attack.
