This chapter deals with the reliability of die interconnections used in plastic discrete power packages, dedicated to on‐board electronic systems used in a wide range of applications such as automotive industry. A complete reliability analysis of two bonding technologies—aluminum wire and ribbon bonding—is proposed. This study is particularly focused on interconnection technologies’ aging, when the package is subjected to thermal cycling or power cycling with high‐temperature swings. For thermal cycling, the experimental reliability test results highlight that wire bond package aging is about 2.5 faster than the ribbon bond package. For power cycling, this acceleration factor is about 1.5. In both cases and whatever the bonding technique, the failure mechanism of the package is of a fatigue‐stress nature. Many failure analysis results show wire bond lift‐off. The degradation of the ribbon bond is more difficult to observe. Thermo‐mechanical simulations using finite elements show a high stress concentration in the heel area. For the wire‐bonding technique, the wire is subjected to repeated flexing and pulling that lead to its lift off. The ribbon‐bonding process shows a higher robustness, thanks to a higher contact surface on the die, the low‐loop profile and the stiffness of the ribbon.
Part of the book: System Reliability