Thermal characterization of a novel 3D stacked package structure by CFD simulation
In this paper, a novel 3D stacked package structure with horizontal fins is designed to solve the heat dissipation issue. In order to verify the thermal performance, a 3D stacked package test vehicle with five chips and two interposers is built in a CFD software Icepak. The size of the chip is in accordance with commercial thermal test chip (TTC 1002, TEA) Three different cooling methods of this architecture are studied, including natural convection, forced air convection, and immersion cooling. Temperature profiles under different external conditions are obtained and analyzed to determine the thermal resistances between adjacent chips qualitatively. Due to the increased heat flow paths, the novel 3D stacked package structure with horizontal fins has a better dissipation effect than traditional structure. The cooling capacity of immersion cooling is the best among the three cooling conditions. Through immersion cooling, the hot spot temperature of this 3D stacked package can be maintained at a low level. The length of the fins is also studied to balance the optimal cooling performance and minimum volume occupancy. The length of the fins is very critical to the optimal cooling performance, especially in natural convection condition and forced air convection condition. The optimal length of the fin should be based on the heat dissipation of chips, the application environment, the reliability and also the costs. This work offers an insight look of thermal management for 3D stacked chips, and this structure is expected to be applied in future electronics.
2016 17th International Conference on Electronic Packaging Technology (ICEPT)