Thermal Characteristics Analysis and Optimization of Heterogeneous 2.5-D Package Under System-Level Conditions

The 2.5-D integrated circuit (2.5-D IC) packages, in which multiple dies or chips are integrated side-by-side on a single interposer, play a crucial role in meeting the high bandwidth and high-performance requirements of merging applications, such as high-performance computing (HPC) and artificial intelligence (AI). However, the high power density in such packages leads to hot spot issues, which raise serious concerns regarding thermal control and management. Therefore, this study uses a thermal impedance experimental testing method to analyze the thermal behavior and characteristics of the 2.5-D package in the module system. Additionally, 3-D computational fluid dynamics simulations were performed to examine the thermal behavior of a typical 2.5-D package under system-level conditions. The results of the simulation are consistent with physical phenomena and confirm the rationality of the numerical model. The Taguchi experimental design to determine the effects of the main design parameters of the 2.5-D package on its thermal resistance under system-level conditions. Finally, the results of the Taguchi analysis are used to establish general design guidelines for minimizing the thermal resistance of the 2.5-D package. Overall, the results indicate that maintaining a consistent die thickness enables the use of a uniform thermal interface material (TIM) layer between the heat sink and the package and hence improves the heat dissipation efficiency. Furthermore, the thermal resistance of the 2.5-D package can be lowered by reducing the TIM thickness and power density, using materials with a higher thermal conductivity for the fin heat sink and TIM, and increasing the fan speed and number of fins.