P. Schelling, Shi, L., and Goodson, K. E., “Managing Heat for Electronics,” Materials Today, vol. 8, no. 6, pp. 30–35, 2005.
Increasing power densities and decreasing transistor dimensions are hallmarks of modern computer chips. Both trends are increasing the thermal management challenge within the chip and surrounding packaging, as well as accelerating research progress on high-conductivity materials. This article reviews recent materials advances with a focus on novel composite substrates and interface materials, including those composites leveraging the high conductivities of carbon nanotubes. Furthermore, attention is given to the special properties of one-dimensional structures that are likely to be of increasing importance in future applications. Thermal management is widely recognized to be an important aspect of computer design, with device performance being significantly affected by temperature. In addition, device lifetime can be decreased drastically because of large thermal stresses that occur especially at interfaces. The ability of a structure to remove heat is best quantified by its thermal resistance, which is given by the temperature difference divided by input power. In microprocessor design, the allowable temperature drop between the transistor (where most of the heat is generated) and the ambient air is constant. As a result, the challenge for thermal management is to develop high-conductivity structures that can accommodate this fixed temperature drop with the increasing power densities that characterize new generations of microprocessors.