Characterization of a liquid-metal microdroplet thermal interface material

This work presents the characterization of a thermal interface material consisting of an array of mercury microdroplets deposited on a silicon die. Three arrays were tested, a 40 × 40 array (1600 grid) and two 20 × 20 arrays (400 grid). All arrays were assembled on a 4 × 4 mm² silicon die. An experimental facility which measures the thermal resistance across the mercury array under steady state conditions is described. The thermal interface resistance of the arrays was characterized as a function of the applied load. A thermal interface resistance as low as 0.253 mm² K W⁻¹ was measured. A model to predict the thermal resistance of a liquid-metal microdroplet array was developed and compared to the experimental results. The contact resistance of the mercury arrays was estimated based on the experimental and model data. An average contact resistance was estimated to be 0.14 mm² K W⁻¹.