Heat Dissipation Capability of a Package-on-Package Embedded Wafer-Level Package

In this work, the thermal analysis is performed to investigate and improve the heat dissipation capability of the fan-out eWLP POP structure. The simulation scheme was validated with the available experimental results conducted previously by Hoe et al. [9]. The 3-D package studied is shown in Figure 1. The thermal performance of the initial POP structure is evaluated as the baseline case. Then, the impact of the internal factors (thermal properties and geometries) on heat dissipation capability of the 3-D packages is investigated and compared. In the mobile device scenario, passive cooling solutions are explored for heat removal improvement. The topside thermal cap provides additional thermal paths between the top and bottom packages, and achieves pronounced temperature decrease. The package lid of larger size and direct thermal path to PCB has enhanced the heat spreading capability, and achieved effective heat conduction from both top and bottom packages to the outside environment. A total heating power of 4 W in the POP can be dissipated, while maintaining the maximum die temperature under the operation limit (85 °C).