Thermal degradation of epoxy novolac-phenol formaldehyde novolac resin systems



The evolution of organic vapors from encapsulants at elevated temperatures has been implicated as the source of the degradation of the gold–aluminum intermetallic of the wire that connects the bond pad to the leadframe in an integrated circuit. Gas chromatography/infrared spectroscopy/mass spectrometry were used to study the decomposition of three commercial epoxy-novolac thermosetting compounds. Outgassing products have been identified and their origins discussed. Insight into the types of initiators used in encapsulants and their possible influence upon ball bond failure rates has been gained.