Analyses of contaminant mobile ions in silicone encapsulants for hermetically equivalent (nonhermetic) IC packaging

In situ ionic contaminants, such as sodium, potassium, and chloride, affect the electrical reliability performance of encapsulated integrated circuit (IC) devices. Silicones (either elastomers or gels) are some of the best device encapsulants. However, the purity of the silicone encapsulant is an important issue in hermetically equivalent IC packaging applications. Procedures for analysis of contaminants in the bulk silicone matrix have been developed and evaluated for reproducibility and applicability determining acceptability of encapsulant materials for bipolar, metal oxide semiconductor (MOS), and hybrid IC packaging. These procedures are based on the use of selective ion electrode and atomic absorption techniques to quantify the contaminant ions in the parts per million (ppm) level