Analysis of Package-to-System Interaction on Thermal Performance of Large 2.5D Packages Using 3DFabric® Platform

With the increasing package size and power consumption of HPC applications, controlling the thermal performance impact from the package-to-system interaction (PSI) in 2.5D/3D chiplet or heterogenous integration packages is crucial for ensuring their long-term reliability in typical operating environments. The present study thus conducts an experimental and numerical analysis of the thermal performance impact of the PSI in a large lidless type 2.5D chiplet heterogeneous integration system with a fanout area more than twice the size of the reticle. The analysis focuses particularly on the effects of the heatsink contact pressure and thermal interface material (TIM) on the thermal performance of the package. The results show that the on-die temperature distribution varies inversely with the heatsink contact pressure. Furthermore, the power cycling test results indicate that phase change materials (PCMs) suffer less degradation than thermal grease after prolonged cycling due to the avoidance of a pump-out effect. Overall, the results suggest that a uniform heatsink contact pressure and the use of PCM materials as the TIM are essential factors in improving the stringent thermal and reliability requirements of high power and large 2.5/3D HPC packages in system environment.