Influence of Ball Size and Geometry on the Reliability and RF Performance of mmWave System-in-Package: A Simulation Approach

Solder ball reliability is a long-discussed topic in microelectronic packaging. With new package types needed for mmWave applications a trade-off between reliability and RF performance may arise, when the solder ball geometry has to be selected for specific package assemblies. In this work, the lifetime for different solder ball geometries is investigated within a numerical simulation workflow, by means of a sensitivity analysis in which the ball diameter, pad sizes and stand-off distance are varied. Next to lifetime estimations, 3D full-wave simulations have been applied to analyze the RF performance of the structures under investigation at 77-79 GHz (E-band) center frequencies relevant for automotive radar applications. Finally, the trade-off between RF performance and reliability is illustrated and quantified.