“…With the rapid development of electronic packaging technology, more and more package on package (POP) system products has been widely used, such as smartphone, laptop and so on. We have paid more and more attention to the reliability of the POP stacked chip assembly (Eslampour et al, 2013;Yang et al, 2019;Yang et al, 2014b). Thermal cycling is thought to be the main cause of package fatigue failure (Chen et al, 2015;Zhang et al, 2017).…”