三维网络（CNTs+GNs）/Cu微电子封装复合材料合成理论与热传导机理研究

High-speed development of chip integration level makes the loaded power of chip be more and more high, so the heat dissipation capacity of packaging materials have to meet the more strict requirements. Single materials are difficult to meet the requirements of comprehensive performance of packaging products. At present, the metal matrix composites with the high volume fraction have some problems such as bad bonding of metal ceramic interface, aggregation of ceramic phase, and the low density and heat conduction, so they are difficult to meet the needs of chip' heat dissipation ability under the super power. This subject is based on a prior national fund project. A three dimensional network (CNTs+GNs)/Cu microelectronic packaging composite material was designed and synthesized by using ultra-high heat conductivity of carbon nanotubes (CNTs) axial and graphene (GNs) surface and the advantage of copper on the structure and performance, through catalytic technology, the improved CVD, lithography, electroplating, directional growth technology, the collaborative application of hot pressing sintering technology, in order to solve science and technology bottleneck problems appeared in the process of the material design and synthesis, prove mechanism of CNTs and GNs in the synthesis and heat transfer of three dimensional network (CNTs+GNs)/Cu packaging material, provide new theoretical basis and research approaches to obtain new microelectronics packaging composite materials. This project is expected to fundamentally solve the obstacles in the application for a metal based microelectronic packaging composite materials.

高速发展的芯片集成度使其承担功率越来越高，对封装材料的散热能力提出更严格的要求。单一材料难以满足封装产品性能要求，目前使用的金属基复合材料因存在金属陶瓷界面结合不好、陶瓷相团聚、致密度和热传导较低等问题，而难以满足超大功率下芯片散热能力的需求。本课题是在前一个“国基”基础上利用超高的碳纳米管(CNTs)轴向和石墨烯(GNs)面内热导率，及金属铜在结构和性能上的优势，通过催化技术、改进CVD技术、光刻技术、电镀、定向生长和热压烧结技术的协同应用，以设计和合成三维网络互穿(CNTs+GNs)/Cu电子封装复合材料为目标，解决其在设计和合成过程中出现的科学问题和技术瓶颈，探明CNTs和GNs在合成三维网络(CNTs+GNs)/Cu封装材料和热传导过程中的作用机理，为获得新型微电子封装材料提供新的理论基础和研究途径。该项目的设立将有望从根本上解决阻碍金属基电子封装复合材料广泛使用的问题。

按照项目书的要求，研发了使粉体分散的翼鼓装置，成功地利用该装置在SiC微米颗粒表面上实现了金属铜离子的注入，解决了金属铜离子与陶瓷离子之间的润湿性；利用化学共沉积、电沉积技术在铜粉、铜箔上制备催化剂，可控合成出了CNTs。详细论述了合成条件对铜箔上石墨烯沉积的影响规律，阐明了石墨烯的形核长大机制。同时，在无催化剂的情况下，仅经过氢气刻蚀，利用CVD技术实现了碳纳米管在H62黄铜箔上的生长；完成了铜箔上四种（正方形、正六边形、三角形和圆形）纳米管和石墨烯图案的设计和可控合成；正方形图案的（CNT+GN）s/Cu复合膜的蓄热能力、均热能力和热传导能力最高，然后依次为正六边形和三角形，圆形图案的上述三种能力最低。图案化（CNT+GN）s/Cu复合膜的蓄热能力、均热能力和热传导能力呈现较为明显的各向异性：面内的三种能力均高于跨面的，温度对（CNT+GN）s/Cu复合膜面内的蓄热能力、均热能力和热传导能力影响较大，但对跨面影响不明显。将铜箔上沉积的石墨烯复合膜安装到笔记本电脑，使其CPU温度下降了2-5℃。.利用热压和烧结技术成功地制备了满足实际需要的（CNT+GNs）-SiC/Cu和（CNT+GN）s-SiC/Cu复合材料，CNTs-SiC/Cu热膨胀系数在（6.5-7.3）×10-6/℃，560～600W/m.K。与石墨烯电极材料比较，图案化三维石墨烯/碳纳米管复合材料在1.0 mol/L Na2SO4电解液中扫描速度为40 mV/s时的最大比电容为333 F/g，提高27%。基于本项目研发的石墨烯和纳米管，设计和制备一种可以集靶向造影、辅助抑制血栓功能于一体的新型多功能造影剂。. 本项目解决了铜箔、铜粉上碳纳米管和石墨烯合成和生长的科学问题，阐明了散热机理，在散热器、超级电容器和造影剂方面进行初步应用。. 本项目发表SCI论文9篇，发明专利3项，学术著作4部，培养博士生1人和硕士生2人。