Thermal Performance Analysis of a Silicon Chip (IC) Mounted on Printed Circuit Board for Different Substrate Materials Based on the Convection Heat Transfer by 3D Finite Element Method

Abstract

A silicon chip (IC) is made of billions of transistors having non negligible electrical resistance and dissipates heat to surrounding based on its running speed (clock speed). Natural cooling is not sufficient enough to keep the temperature of the chip at safe limit. In this present model we investigated temperature field of a silicon chip volume (dissipating heat to surrounding at a particular rate) mounted on PCB for various substrate materials (FR4, PTFE, Polyimide and Silicon-nitride) based on convective heat transfer coefficient (a coefficient which depends on the external cooling fluid and PCB) with appropriate boundary conditions. 3D conduction equation, Newton’s law of cooling, Stephen-Boltzmann equation have been used for this investigation. Finite element method (FEM) is used to solve the governing equations. Both steady state and transient analysis (up to 10 min) have been done. The results of the investigation have been shown by 3D temperature distribution throughout the silicon chip volume for various substrate materials. Effect of convective heat transfer coefficient on maximum temperature on chip volume for different substrate materials have also been presented. It has been seen that substrate materials (FR-4, PTFE, Polyimide and Silicon-nitride) have a negligible effect on thermal performance of silicon chip. But FR-4 substrate shows best performance compared to other substrate since it induce less maximum temperature on silicon chip volume which will results in less thermal stress on silicon chip. It has also been seen that as convective heat transfer coefficient increases maximum temperature on silicon chip domain decreases gradually. So to attain best cooling performance we have to increase the convective heat transfer coefficient which can be done via several process like using nanofluid and some other highly efficient CPU cooler.