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

摘要这项早期概念探索性研究奖助金为用于散热应用的新型铟-石墨烯和铜-石墨烯复合材料的加工和表征提供了资金。加工步骤包括用分散的氧化石墨烯轧制铟和铜箔，然后进行中间加热，以防止石墨烯在复合材料中团聚。氧化石墨烯还原成石墨烯所形成的金属氧化物将被铟熔剂或使铜-石墨烯复合材料在更高的温度下受氢去除。复合材料中石墨烯的大小和均匀分布将通过包括扫描和透射电子显微镜在内的先进方法进行表征。导热系数将通过实验确定为温度和石墨烯在复合材料中的体积分数的函数。通过测量石墨烯与基体金属之间的界面热导来验证它不是实现复合材料高导热系数的限制因素。将对复合材料的热传输特性进行模拟，以评估石墨烯和金属基质的微观结构特征、界面导热系数和导热系数的重要性。半导体晶片将使用铟-石墨烯复合焊料连接到铜-石墨烯复合材料上。粘结结构将经历热循环，以确定脱粘的稳定性和抗破坏能力。如果研究成功，本研究结果将显著提高热界面材料和散热器的导热系数。对高频大功率电子器件和激光器的可靠性和运行非常关键的热能消耗瓶颈将被消除。本研究的主要目标是制备石墨烯均匀分散的石墨烯复合材料，并获得高的散热能力。根据单个组分的性质确定热输运性质将有助于确定石墨烯的贡献，石墨烯被认为是未来的新型电子材料。该项目开发的低成本制造方法将使半导体和激光封装技术能够克服热管理问题。

AbstractThis 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.