127 3 rd IEEE International Conference on Adaptive Science and Technology (ICAST 2011) 978-1-4673-0759-8/11/$26.00©2011 IEEE Investigation of Effects of Heat Sinks on Thermal Performance of Microelectronic Package Mathias Ekpu*, Raj Bhatti, Ndy Ekere, Sabuj Mallik, Emeka Amalu, Kenny Otiaba Manufacturing Engineering Research Group, School of Engineering University of Greenwich at Medway, Chatham, ME4 4TB, Kent, U.K. M.Ekpu@greenwich.ac.uk, mathiasekpu@yahoo.com Abstract- The concern about thermal performance of microelectronics is on the increase due to recent over-heating induced failures which have led to product recalls. Removal of excess heat from microelectronic systems with the use of heat sinks could improve thermal efficiency of the system. This paper investigates the effect of change in heat sink geometry on thermal performance of aluminium and copper heat sinks in microelectronics. Numerical studies on thermal conduction through an electronic package comprising a heat sink, chip, and thermal interface material were carried out. The thickness of the heat sink base and the height of the heat sink fins were varied in the study. The minimum and maximum temperatures of aluminium and copper heat sinks in the two models were investigated using steady state thermal conduction analysis. Better heat dissipation occurred in thinner base thickness and extended fins height for both aluminium and copper heat sinks. Aluminium heat sink recorded the lowest minimum temperatures in both investigations and is recommended as optimal thermal management material for heat sink production. Keywords: Electronic package, heat sink, microelectronics, temperature, thermal performance I. INTRODUCTION In recent years, it is evident that heat generation in microelectronics devices has increased significantly [1]. Thermal failures in such devices are common a fault associated with overheating. Efficient removal of this heat energy is vital to the good performance of the device, especially when over-heating has resulted in the failure of recent electronic devices such as laptop computers. A laptop computer is an example of a device where heat management could become a concern. For instance, manufacturers of high speed computers [2] have recently recalled some products due to temperature activated failures. Heat sinking device could be used to reduce thermally induced failures by enhancing heat dissipation from the device. Heat sink is a structural device that dissipates heat from a functional electronic package to the environment to ensure the device operates within safe temperature limits [3]-[9]. This study investigates a rectangular flat pin heat sink because of its good reliability and relatively low production cost [6]. Heat sink geometry is an important factor in microelectronics thermal management. It is a factor that influences heat dissipation through the heat sink to the environment. Heat is conducted from a chip device through a heat sink which dissipates the heat to the environment. Thermal management materials such as aluminium and copper are used for the production of heat sinks. This is because of the high thermal conductivity and reasonably low coefficient of thermal expansion properties exhibited by both materials. Due to miniaturization of electronic devices, low density thermal management materials are preferred. It is not surprising that aluminium is mostly used as heat sink materials over copper in recent years. Copper is three times heavier than aluminium and also costly. In this paper, attention has been focused on improving thermal management and thus performance of microelectronics devices such as laptop computers. The thermal performance could be improved by minimizing the geometry (size) of the metal heat sinks. The steady state thermal conduction analysis was used to investigate the effect of base thickness and fin height on thermal performance of aluminium and copper heat sinks. The heat dissipation through aluminium and copper heat sinks was studied. II. NUMERICAL MODEL A. Model Description A geometric model was designed using Ansys workbench version 13. Fig. 1 shows schematics of the electronic package model which comprised of a top mounted heat sink, a chip and thermal interface