A semi-empirical model is derived to predict the board level drop-impact lifetime of HVQFN-packages soldered on a printed circuit board. The strain that evolves in the soldered interconnections is evaluated by a finite element model and related to the experimentally determined lifetime. The result is a power law and it is compared to literature data. In addition, a measure for the strain on the board is obtained analytically and compared with the experimental data. Here, too, dependence in the form of a power law is found. The combination of both results strongly suggests a near-linear relationship between the strain in the solder and the strain in the board.@en

In this work experimental results of thermal cycling tests on HVQFN-packages mounted on printed circuit boards are combined with finite element analyses. Validating the finite element analyses by a selected series of small, medium and large HVQFN-packages assembled on printed circuit boards, allows us to determine the performance of this family. To be able to do that, the discriminating parameters that determine the board level performance of this family need to be understood. The emphasis is on the fatigue life of the soldered interconnections as it is influenced by the thermal stress load, the board thickness, and the dimension of the package. Data from different experimental set-ups are compared. An important parameter in this respect is the inclusion of the base material of the panels. The test loads were set to cycling at -40 degrees C/+ 125 degrees C and -20 degrees C/+100 degrees C. The results prove that the essential physical properties governing the fatigue life are the stiffness of the complete assembly and the thermal expansion mismatch between the parts.@en