Qualification guidelines for automotive packaging devices

With the continued demand for miniaturization, with the advent of new materials and processes, and with increased demand for better performance and lower cost, reliability of microelectronic devices continues to be a major concern. As microelectronic packages are used in a wide range of applications from automotive to aerospace to telecommunications to biomedical devices, there is a need for developing suitable qualification standards for these application domains. The ongoing work at Georgia Tech aims to develop a comprehensive virtual qualification system taking into consideration the process mechanics of substrate fabrication and component assembly, time- and temperature-dependent material behavior, process-induced defects, and critical geometric features of the assembly. The objective of this paper is to present one such virtual qualification technique for microelectronic packages used in automotive applications. Numerical models have been developed that take into account the creep behavior of the solder joints, the viscoelastic behavior of the underfill and the temperature-dependent orthotropic properties of the substrate. The models account for the solder reflow process and underfill cure process. They also account for multiple reflow and burn-in testing of the devices. Based on the information collected in terms of weather, underhood conditions, and driving profiles, qualification temperature cycling guidelines have been developed for automotive devices. The possibility of backside die cracking due to tensile stresses has also been investigated. The results from the models are being compared against experimental data from in-house as well as industrial sources.