Integrated Microfluidic Cooling of Heterogeneous HBM-GPU Package Exploiting Die Height Mismatch
The 2.5-D heterogeneous integration of high-bandwidth memory (HBM) and graphics processing units (GPUs) has become a key technology for high-performance computing. However, increased power density exacerbates thermal challenges. We propose a manifold-microchannel heat sink exploiting the die height mismatch between the GPU and HBM. By replacing conventional structural silicon with a microchannel structure, this design leverages the height variance to enhance fluidic cooling. To reduce computational cost, a unit cell was modeled applying symmetry boundary conditions. Using the CFD and Heat Transfer Modules in COMSOL Multiphysics®, we numerically analyzed the temperature distribution. We evaluated the maximum GPU temperature across varying flow rates and calculated pumping power from the inlet-outlet pressure drop. The proposed manifold structure demonstrated exceptional cooling performance for a total heat dissipation of 2228 W (a 2000 W GPU and six 38 W HBMs). At a flow rate of 1.8 L/min and a minimal pumping power of 0.1656 W, the maximum temperature rise was suppressed to 342.12 K. This study provides design guidelines for advanced microfluidic cooling solutions to address the escalating power densities in 2.5D packaging architectures.
