Thermal characteristics of silicon wafer-based TVCs (thin vapor chambers) with disk-shape using DI water

Abstract

This paper analytically and experimentally investigates the thermal characteristics of disk-shaped, silicon wafer-based thin vapor chamber (TVC) using de-ionized water as the working fluid. The maximum heat transfer rate, the maximum temperature, and the thermal resistances of the TVCs were measured experimentally. An analytical model based on the modified liquid pressure drop through a micro-pin–fin wick and the capillary limit was developed to determine the maximum heat transfer rate. In addition, a thermal resistance model was developed for the TVC that was used to calculate the maximum temperature from the maximum heat transfer rate. The maximum temperature of TVCs is ensured to not exceed the maximum allowable temperature of the electronic components. The silicon wafer-based TVCs, which have an overall thickness of 1 mm and radii of 5 mm, 7.5 mm, and 10 mm, were manufactured by using both deep reactive ion etching (DRIE) and Ionic bonding. A laser heat source and an IR camera were used not only to eliminate the effect of a thermal contact resistance between the heat source and the TVCs, but they were also used to observe the burn-out phenomena in the TVCs directly. The analytical model was shown to predict most of the measured data within ±10%. The effect that key TVC design parameters, such as the TVCs’ radius, the fin diameter, and the wick height, had on its maximum temperature and its thermal resistance were illustrated with the model and the measurements.