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Accelerated determination of interfacial fracture toughness in microelectronic packages under cyclic loading

: Poshtan, E.A.; Rzepka, S.; Silber, C.; Wunderle, B.


Institute of Electrical and Electronics Engineers -IEEE-; IEEE Components, Packaging, and Manufacturing Technology Society:
IEEE 65th Electronic Components and Technology Conference, ECTC 2015. Vol.2 : San Diego, California, USA, 26 - 29 May 2015
Piscataway, NJ: IEEE, 2015
ISBN: 978-1-4799-8610-1
ISBN: 978-1-4799-8609-5
Electronic Components and Technology Conference (ECTC) <65, 2015, San Diego/Calif.>
Conference Paper
Fraunhofer ENAS ()

An accelerated and cost-effective characterization method for bi-material interfaces under cyclic loading using a Miniaturized Sub-Critical Bending (MSCB) test setup is presented. The Modified Single Leg Bending (MSLB) samples are acquired directly from production-line, Thin Quad Flat Package (TQFP). Under sub-critical cyclic loading, crack was found to occur at the polymer-metal interface. The crack length is measured using a numerical-experimental compliance-based method. In addition influence of temperature on interfacial adhesion properties namely, crack initiation and propagation is discussed. Sub-critical crack growth (SCCG) is captured along the surface between Molding Compound (MC) and copper Lead-Frame (LF). It is shown that crack propagation along MC/LF interface is highly fatigue sensitive. In addition the fatigue tests under different temperatures show that critical (Gc) and sub-critical strain energy release rate (Gth) are highly temperature-dependent. Finally the samples are fractographically examined using Scanning Acoustic Microscopy (SAM) and Energy-dispersive X-ray spectroscopy (EDX).