Vibration-Fatigue Assessment On Electronics Interconnections
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Date
2022-07-24
Authors
Wong, Zie Jen
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
Many devices consist of electronic parts and can be operated in a certain
vibration environment for some instant without undergoing failure. Interconnection or
joint plays a very important role in electronic devices to connect various electrical and
mechanical parts altogether. Electrically conductive adhesives (ECA) are becoming a
trend for the green substitute of solder as electronic interconnections. However,
reliability of the ECA joint has not been adequately addressed in academic papers. The
main objective of this study is to perform the vibration fatigue assessment of
electrically conductive adhesive under vibration loading. Different combination of
ECA materials including epoxy, silicone, and acrylate is assigned into a total of 8
simulation models with high-quality meshing. Next, modal analysis is carried out to
determine the natural frequencies and mode shapes of model from 0 Hz to 2000 Hz. It
is followed by the random vibration analysis and harmonic response analysis with the
input PSD curve referred to JEDEC Standard. Lastly, Steinberg fatigue model is used
to estimate the number of fatigue cycles and fatigue damage. Based on FEA results,
maximum output of response occurs at, or near the dominate natural frequency at 1st
vibration mode. This analysis helps engineers to consider changing the design to shift
or even eliminate that natural frequency. On the other hand, it can be concluded that
increasing elastic modulus, and thus stiffness as well as decreasing inertial mass of
component can increase the fundamental frequency which in turn results in extended
fatigue life. Acrylate with high elastic modulus and low mass density among polymer
types can thus has highest vibration reliability to withstand vibration induced stress
compared to epoxy and silicone ECAs. Overall, the effect of mechanical properties of
different solder, substrates and die materials in a circuit board assembly on the
vibration reliability of electrically conductive adhesive (ECA) is identified.