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Impact of RDL Polymer on Reliability of Flip Chip Interconnects in Thermal Cycling - Correlation of Experiments with Finite Element Simulations

: Müller, Matthias; Wöhrmann, Markus; Wittler, Olaf; Bader, Volker; Töpper, Michael; Lang, Klaus-Dieter


Institute of Electrical and Electronics Engineers -IEEE-; IEEE Components, Packaging, and Manufacturing Technology Society:
ESTC 2014, Electronics System Integration Technology Conference : Helsinki, Finland; 16.09. - 18.09.2014
Piscataway, NJ: IEEE, 2014
ISBN: 978-1-4799-4026-4
ISBN: 978-1-4799-4027-1
ISBN: 978-1-4799-4025-7
Electronics System Integration Technology Conference (ESTC) <5, 2014, Helsinki>
Fraunhofer IZM ()

For WLP (Wafer Level Packaging) thin film polymers play a key role in respect to board level reliability. This paper introduces a reliability indicator giving a tendency of the polymer material to crack initiation around the UBM pad. This indicator derived from Finite Element simulated maximum stress in polymer layer and the material specific tensile strength. Comparing the simulation results with the experimental data we see the same impact of the mechanical material properties on the reliability. This proves the described reliability indicator as suitable for estimating thermal cycle reliability of RDL polymer materials gives application engineers and manufacturers a new tool for selecting the most suitable RDL material for e.g. flip chip and WLP applications.