A Bonding-Wire Failure Mode in Plastic Encapsulated Integrated Circuits

Dual-in-line plastic packages (DIPs) from several different suppliers have been found to have open or intermittent open leads after routine thermal cycling tests. The failure mode has been duplicatated in the laboratory by placing gold bonding wires under tensile stress at different temperatures for varying times. Confirtuation of the tensile failure mode has led to the conclusion that to avoid tensile. failures, the plastic and the molding process used for DIPs must be such that the wire is kept under compressive stress over the entire working temperature range of the circuit.