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2024
Journal Article
Title
Solder fatigue life modeling of QFN components based on design of experiments
Abstract
Shorter development times and increasing cost-efficiency make it necessary to predict the reliability of electronic assemblies at an early stage. Within this framework, this work focuses on the influence of load and geometric parameters on the solder fatigue life of Quad Flat No Leads (QFN) components. Following a Design of Experiments (DoE) test plan, the following design parameters affecting the solder fatigue life are investigated: the number of leads and the pitch, the orientation of the component on the Printed Circuit Board (PCB), the constant ambient temperature and the surface strain. A test setup is used in which each parameter can be varied individually. From the resulting lifetimes, a multiple regression model and a physical-based model are derived. The regression model shows a slightly better fit quality due to its higher degree of freedom and is not subject to any physical constraints. The physical-based model is a combination of different proven solder fatigue life models and avoids any overfits which can occur in a regression model. Based on these models, the influence of the parameters on the solder fatigue life and the relationship between the parameters and the solder fatigue life is evaluated. With these results, it is possible to predict the lifetime with respect to mechanical load cases depending on size, orientation and surface strain as well as thermal load. This opens up completely new possibilities in PCB design by significantly improving the quality of solder fatigue life prediction and significantly reducing the restricted areas for component placement.
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