An in-situ numerical–experimental approach for fatigue delamination characterization in microelectronic packages

• An accelerated numerical-experimental approach for fatigue delamination characterization in microelectronic packages.
• A Miniaturized Sub-Critical Bending (MSCB) test set-up is designed for production-line samples.
• Interfacial Sub-critical crack growth under different thermal conditions is investigated.

An in-situ and cost-effective numerical–experimental approach for fatigue characterization of bi-material interfaces in microelectronic packages is presented. In this method using a sample-centered approach, a miniaturized sub-critical bending (MSCB) test setup is designed and fabricated based on the samples that are acquired directly from the production-line. Sub-critical crack growth (SCCG) is captured along the surface between molding compound (MC) and copper lead-frame (LF) in the samples prepared from Thin Quad Flat Package (TQFP). The toughness values such as critical (Gc) and sub-critical strain energy release rate (Gth) are measured. It is shown that crack propagation along the MC/LF interface is highly fatigue sensitive. In addition, fatigue–fracture tests under different isothermal conditions reveal that, the toughness values are higher in lower temperatures. The fractographical study of samples shows that, although some of the molding compound particles are left on the LF surface, the interfacial fracture is the dominant failure mode.