Computer simulation of the reliability of wire bonds and ribbon bonds in power electronics modules

Aluminium wires are widely used in power electronics modules to connect power semiconductor devices and other parts of the module electrically. Recently, other interconnect techniques have been proposed such as ribbon bond to improve the reliability, performance and reduce costs of power modules. The reliability of ribbon bond technique for an IGBT power module under power cycling is compared with that of conventional wire bond in this study using electro-thermal nonlinear Finite Element Analysis. The results showed that a single ribbon of 2000μm × 200μm will replace three wire bonds of 400μm in diameter to achieve a similar module temperature distribution under same power load. Using the equivalent plastic strain increment per cycle, it is seen that the ribbon bond is more reliable than the wire bonds. The impact of neglecting joule heat in the wire/ribbon bonds during power cycling simulation has also been investigated.