EAGER: Processing and Characterization of Novel Indium-graphene and Copper-graphene Composites for Heat Spreader Applications

North Carolina State University, Raleigh NC

Investigators

Abstract

Abstract This EArly-concept Grants for Exploratory Research (EAGER) grant provides funding for the processing and characterization of novel indium-graphene and copper-graphene composites for heat spreader applications. The processing steps will consist of rolling indium and copper foils with dispersed graphene oxide followed by intermediate heating so that agglomeration of graphene in the composites is prevented. The metal oxide formed by reduction of graphene oxide to graphene will be removed by indium flux or by subjecting the copper-graphene composite to hydrogen at higher temperature. The size and uniform distribution of graphene in the composites will be characterized by advanced methods that include scanning and transmission electron microscopy. The thermal conductivity will be determined experimentally as a function of temperature and volume fraction of graphene in the composites. Measurement of interfacial thermal conductance between graphene and the matrix metal will be performed to verify that it is not a limiting factor to achieve high thermal conductivity of the composites. Modeling of the thermal transport properties of the composites will be carried out to evaluate the importance of microstructural features, interfacial thermal conductance, and thermal conductivity of graphene and metal matrix. Semiconductor wafers will be bonded to the copper-graphene composites using the indium-graphene composite solder. The bonded structures will be subjected to thermal cycling to determine the stability and resistance to failure by debonding. If successful, the results of this research will lead to significant improvements in the thermal conductivity of the thermal interface material and heat spreader. The bottleneck to thermal energy dissipation, which is very critical to the reliability and operation of high frequency and high power electronic devices and lasers, will be eliminated. The primary goal of the present research is to process graphene composites with uniform dispersion of graphene and achieve high heat spreader capability. Determination of thermal transport properties in terms of the properties of the individual components will be helpful to determine the contribution from graphene which is considered the future novel electronic material. Low cost manufacturing methods developed in this project will enable semiconductor and laser packaging technologies to overcome the thermal management problems.