Effect of geometric complexities and nonlinear material properties on interfacial crack behavior in electronic devices

• We develop a FEA framework to predict interfacial crack behavior.
• We incorporate the geometric complexities of a wavy interface.
• We compare crack behavior across one unit intermetallic cell.
• Interfacial toughness estimates show strong sensitivity to roughness.
• Effect of initial crack length and load rate is minimal.

Interfacial failures are often found in solder joints between electronic components and PWAs, under shock and drop loading. These interfacial fractures are often either between layers of dissimilar intermetallic compounds (IMCs), or between the solder and IMC layer. Studies have revealed that these interfaces are usually scalloped (wavy and non-planar) and that the waviness decreases with continued thermal aging, accompanied by a reduction of the apparent resistance to interfacial crack initiation. This study investigates the effects of the interfacial waviness, nonlinear solder material properties, local geometric complexities, and the initial crack length, on the resistance to crack initiation. Most of the studies in this field until this point have been either simple theoretical models not including all complexities or few limited experimental work. A computational framework is generated here to comprehensively include all important parameters that can then make efficient predictions cost-effectively and provide insights on the dependency of the interfacial fracture properties on all these parameters. Accurate and efficient assessment of such fracture properties will inherently help in designing reliable electronic assemblies and prevention of premature field failures.