Comparison of Thermal Performance of Current High-End Thermal Interface Materials

Reactive NanoTechnologies (RNT) has developed a reactive bonding technology to directly bond silicon dies to heat sinks with indium solder using a reactive multilayered foil. In this new method of bonding, heat is generated locally by exothermic mixing within the multilayered foil. This heat is used to melt indium solder layers to join the dies to the heat sinks. The measured thermal resistance of the resulting solder bond is 4 to 5 K mm²/W (0.006 to 0.008 K in²/W). In addition, the reactive foil also localizes the heat to the interface, thus minimizing residual stress and thermal damage in the components. In this paper we discuss the thermal performance and reliability test results for reactive multilayer bonding with different bond line thicknesses. We also present detailed comparisons of thermal performance between reactive multilayer bonding and other current Thermal Interface Material (TIM) solutions, including polymer-based greases, phase change materials, and low melting metallic alloy. Benchmark tests were done using the graphics processor on an operational video card as a test vehicle. The test results show that the introduction of a reactive multilayer bond as an interface material between the graphics processor and the thermal management device demonstrates significant performance advantages over any of the other current commercially available TIM solutions.