3D modeling and simulation of heat transfer for internal channel cooling of 3D-chip stacks

This paper presents a configuration of 3D-chip stacks with internal channel cooling that include high thermal conductivity layers, channels for heat transport by pneumatic fluid flow, regulation of fluid velocity by channel obstructions bumps, enhanced thermal conductivity across the channel by metal spacers, wiring re-distribution layers (RDL) and electrical continuity across the cooling channels. Finite element (FEM) method was used to present numerical simulations based on the configuration. The temperature distribution, hotspot and average velocity in the channel of three layers under different gas pressure drop and different power density are investigated. The simulation results show that the gas cooling 3D-chip stacks construction can dissipate 30W/cm2. Compared with water channel cooling, the gas cooling structure is of simpler construction and a small leak does not always require immeriate system shut-down.