Thermal Management in a 3D-PCB-Package with Water Cooling

The 3D-packaging technology makes it possible to stack the PCBs on top of each other and thus make full use of the third dimension. A unique space between the stacked PCB layers enables a reproducible technology without shortcuts or unconnected bumps. New applications in 3D-PDB-packages, called PCBMEMS can be realized with the combination of electric bumps and solder rings. The paper shows a fluidic cooled 11-PCB-layer with high power components. Water channels in the PCB-package dissipate the heat from the inside of the package to the environment. Heat dissipation is a bigger challenge for stacks of 3D-packages than for normal printed circuit boards (PCBs). This research paper investigates some design suggestions for a better heat dissipation. On the basis of this research paper, it becomes possible to choose the best suited PCB design. The experimental results were compared to thermal simulation results. The results of the measurements and FEM simulations show how important it is to combine the electrical and geometrical functions of 3D packages with a thermally optimized PCB design. A better heat spreading and conduction in a 3D package makes the stack more reliable at higher power dissipation