Numerical simulation and thermal analysis of PoP packaging

In this paper, by establishing PoP (package-on-package) packaging model, numerical simulation method was used to conduct the steady-state thermal analysis under a given power condition and the influence of thermal conductivity of packaging materials, including PCB (Printed Circuit Board), the number of chips and power distribution on the temperature of PoP packaging were explored. Finally, the distribution of stress field of package was also investigated based on the results of temperature distribution. Simulation results show that the highest temperature occurs in the center of the chip and gradually decreases to the surrounding environment. The increase of thermal conductivity for packaging material can reduce the package temperature remarkably to an acceptable extent and the entire temperature of package rises with the increasing number of chips. The design of chip power has an effect on the package temperature and location of the maximum temperature. Large stress occurs due to the difference of thermal expansion coefficient between balls and substrates, which may result in the failure of PoP.