Towards optimizing enhanced surfaces for passive immersion cooled heat sinks

Reduction in die feature-size due to improvements in microelectronics fabrication technology have increased the demands on effective thermal management. As a consequence, innovative heat removal schemes must be explored. Immersion cooling in a dielectric fluid, despite the increased complications, continues to be studied as a possible solution. The characteristics of a surface used as a pool boiling heat sink depend on its microscopic features. This paper reports results from an investigation in which the shape and spacing of these microscopic features were studied in order to achieve improved thermal performance. The heat sources were thin-film heaters deposited in an array on a silicon wafer which was immersed in FC-72 coolant.