A Study Of Interfacial Delamination For Embedded Die System In Package

Compared with traditional microelectronic packaging, embedded die system in package can further reduce the package size and cost of the product. Meanwhile, the function and performance of the package structure can be improved. When the thermal cycling and high temperature load are applied the mismatch of the CTE can result in interface delamination. Thus, the promotion and application of the advanced technology in the field of package will be delayed by the reliability problems of the overall package structure. Delamination analysis of an embedded die system in package is mainly studied in this paper.The contents and conclusions are as follows:Firstly, the conventional method is applied to find the dangerous interface in the package. And then, cohesive zone model is set at the die/solder interface which is the dangerous interface based on ANSYS tool. The effect on the interface reliability of interfacial shear strength and critical sliding displacement is studied under thermal shock loads (cooling from175℃to25℃during60s). The effect of the number of chips, the chip thickness, the solder thickness as well as EMC’s Young’s modulus on the interface reliability is also studied under the same thermal loading. The results show that: the die/solder interface delamination appears two diagonal corner initially, and then gradually extends toward the inside; increasing the Young’s modulus of EMC will alleviate the extent of damage of the interface, but also cause the interface crack transfer to the interface center from border; with the increase of the interfacial strength parameters and the critical sliding displacement, the interfacial failure is smaller; chip thickness increasing causes the interface strength reduced; the thickness of solder has little effect on the interfacial reliability.Lastly, the tensile strength of copper nano-rod is studied by the molecular dynamics software LAMMPS. And the Young’s modulus of copper and epoxy are simulated separately by Materials Studio. Meanwhile, nano-scale numerical simulation of epoxy/copper interface strength is studied based on Materials studio software to obtain the tensile stress-displacement curve of the interface. And then the curve is applied as a cohesive zone model parameter after the treatment by equally fracture energy density to study the copper and plastic materials interface failure mechanism with finite element software ANSYS.In this paper, the interface delamination of the embedded die system in package is studied with multi-scale methods, providing some reference value multi-scale study of the reliability of microelectronic packaging for further study.