Steady-state measurements of thermal transport across highly conductive interfaces

Abstract

Interfaces play a critical role in heat dissipation for electronics packaging applications, thermoelectric energy conversion, data center cooling and renewable energy systems architectures. They are particularly influential as device length scales are reduced; in some cases, interfaces are fast becoming the dominant thermal resistors between heat source(s) and heat sink(s). Thus, the need to decrease interfacial thermal resistances (RT) with the use of novel, highly thermally conductive materials (i.e. thermal interface materials, or TIMs) is paramount for the success of next-generation electronics and energy systems. Despite significant progress in the areas of materials synthesis and development, current thermal characterization techniques are not capable of reliably quantifying the resistance to heat flow across high-performance interfaces (i.e. RT less than 1 mm2 K/W). In this work, we develop a new steady-state, miniaturized heat meter bar apparatus capable of measuring RT between 0.1 mm2 K/W and 1 mm2 K/W with less than 10% uncertainty using infrared microscopy. Additionally, we demonstrate a related technique that permits the measurement of TIM thermal conductivity and thermal contact resistance (RC) simultaneously with RT for bonded TIMs having RT between 0.1 mm2 K/W and 1 mm2 K/W. This work is expected to further the development of next-generation TIMs for use in high power density devices.