Natural convection cooling of a three-by-three array of leadless chip carrier packages in a dielectric liquid

Abstract

Liquid cooling of a three-by-three array of commercially available leadless chip carrier packages, mounted on a ceramic substrate was examined. Baseline data were obtained for cooling with pure dielectric liquids. The effects of addition of high thermal conductivity ceramic powder to the liquid were next examined, both for natural and forced circulation conditions. Vertical and horizontal orientations were studied, for two different ceramic particle types, and two different particle sizes for each ceramic. For a range of chip power levels, chip, substrate and cold plate temperatures were measured. Interpretations for these data are provided. A numerical model was developed for the vertical geometry and compared to the measurements obtained.