Convective Heat Transfer From a Stacked Electronic Package

Convective heat transfer from a vertically stacked (3D) electronic package (package-on-package) mounted in between two circuit boards is numerically investigated. Heat transfer and pressure loss characteristics of single chip packages and multiple-chip packages (P-O-P) for both two and four package stack are presented and compared. The package Reynolds number, based on the package height and upstream velocity, ranges from 150 to about 1000. Two channel heights are investigated, a large channel (with bypass > 5B, B is package height) and a small channel (with a bypass = B). The effect of board conduction on the heat transfer performance from the package is also quantified. A surprising finding is that, in the present set of configurations, the heat transfer for a multi-package stack, such as a two-package stack or a four-package stack, can be reasonably predicted using the heat transfer information from a single chip package by employing a simple scalar factor. Finally, the effects of non-uniform heating on the die temperatures of the different packages in a stack are examined