Thermal aspect of material selection for substrate board equipped with high heat flux IC chips

Abstract

This paper investigates the material selection for substrate board equipped with nine silicon heaters that mimic IC chips. This includes computational research on laminar forced convection air cooling of silicon IC chips in electronic components mounted on substrate boards subjected to high uniform heat fluxes in a horizontal channel. Copper clad boards with single and multilayer having thermal conductivities of 8.8, 40.5, and 61.5 W/m K are the substrate materials used in this study. Three-dimensional steady-state conjugate heat transfer with laminar non-isothermal fluid flow module is used from COMSOL Multiphysics 5.4 to study fluid flow and heat transfer. Simulations performed with flowing air velocities of 1.5, 2.5, and 3.5 m/s with very high heat fluxes of 10000, 12500, and 15000 W/m2. It showed that the temperature on subsrate board strongly depends upon placement of heaters, Reynolds number, substrate thermal conductivity. It also found that higher thermal conductivity substrate materials results in heat transfer enhancement and decrease chances of failures of electronic devices. A non-dimensional temperature based correlation is also devised in therms of non-dimensional heat flux, thermal conductivity, Nusselt number, and Reynolds number.