高导热金刚石/铜电子封装材料:制备技术、性能影响因素、界面结合改善方法  

Diamond-Copper Composites with High Thermal Conductivity Used for Electronic Packaging:Fabrication Techniques,Performance Influencing Factors and Interfacial Strengthening Methods

作　　者：赵龙[1] 宋平新[1] 张迎九[1] 杨涛[1] ZHAO Long;SONG Pingxin;ZHANG Yingjiu;YANG Tao(Key Laboratory of Materials Physics of Ministry of Education,Zhengzhou University,Zhengzhou 450001)

机构地区：[1]郑州大学材料物理教育部重点实验室,郑州450001

出　　处：《材料导报》2018年第11期1842-1851,共10页Materials Reports

基　　金：国家自然科学基金(11104331)

摘　　要：随着电子行业的不断发展,第二代热沉材料如钨/铜封装材料、钼/铜封装材料、碳化硅/铝封装材料等已不能满足该领域日益增长的需求。金刚石的热导率为2 300 W/(m·K),是已知热导率最高的物质;铜的热导率为401 W/(m·K),在众多金属中仅次于Ag。金刚石/铜复合材料具有诸多优点:(1)热导率高、强度大;(2)热膨胀系数能够通过改变金刚石与铜的体积分数加以调控,以实现与硅、锗等半导体材料的匹配;(3)具有比金刚石/银复合材料更低的成本以及比金刚石/铝、钨/铜、钼/铜等材料更高的热导率。因此,金刚石/铜复合材料是一种理想的电子封装候选材料。金刚石/铜复合材料的制备技术多种多样,其中粉末冶金、放电等离子体烧结、液相渗透是最适合该复合材料特性也是研究最广泛的技术。液相渗透法又分为无压熔渗法和压力辅助熔渗法,与粉末冶金法和放电等离子体烧结法相比,该法成本低、操作性强,成为近年研究的重点方向。目前,国际上已制备出热导率高达900 W/(m·K)的金刚石/铜复合材料。另一方面,金刚石与铜界面润湿度较差,导致复合材料致密度不高且热导率不易提升。解决金刚石与铜界面润湿度较差的问题成为制备金刚石/铜复合材料的关键,也促使国内外研究者不断尝试在制备工艺环节引入改进措施。目前已探索出两种较为可行的方法:(1)在复合材料制备过程中添加少量B、Cr等活性元素,使这些活性元素与铜形成合金;(2)在制备金刚石/铜复合材料之前,采用化学镀、扩散烧结、盐浴、磁控溅射等手段预先在金刚石表面包覆一层均匀的碳化物。本文总结了金刚石/铜复合材料的国内外最新研究进展及主流制备技术,论述了影响复合材料的热膨胀系数及热导率的主要因素。文章还介绍了改善金刚石与铜的界面润湿度的方法,最后对金刚石/铜复合材料的发�The continuous evolution of the electronics industry causes gradual obsolescence of the second generation of heat sink materials,such as tungsten/copper packaging materials,molybdenum/copper packaging materials and silicon carbide/aluminum packaging materials.Diamond holds the highest known thermal conductivity of 2 300 W/（m·K）,and copper owns the second highest thermal conductivity（401 W/（m·K））after silver amongst the rich variety of metals.The composite materials of diamond and copper enjoy many special advantages：（Ⅰ）high thermal conductivity and high strength;（Ⅱ）the thermal expansion coefficient adjustable by varying diamond and copper contents,enabling thermal expansion matching with semiconductor materials such as silicon and germanium;（Ⅲ）more cost-effective than diamond/silver composites,and more thermally conductive than diamond/aluminum,tungsten/copper and molybdenum/copper,etc.Thus diamond/copper composites have been regarded as an ideal candidate material for electronic packaging.A diverse range of techniques can be used to fabricate diamond/copper composites,but the powder metallurgy,spark plasma sintering and liquid infiltration are the most applicable and extensively researched methods.Liquid infiltration techniques can be classified into pressureless infiltration and pressure-assisted infiltration,which have displayed the features of low cost and high operability and become the hot topic in recent years.And researchers have so far successfully obtained the diamond/copper composite with a thermal conductivity of up to 900 W/（m·K）.On the other hand,plenty of works have proved that poor interfacial wettability between diamond and copper leads to unsatisfactory density,and in consequence,limited promotion potential of thermal conductivity.This makes the issue of wettability a crucialpoint for fabricating diamond/copper composites,and urges intensive research efforts to seek countermeasures.At present,there are mainly two reasonable approaches：（Ⅰ）the formati

关 键 词：金刚石/铜复合材料 热导率 热膨胀系数 电子封装 

分 类 号：TB331[一般工业技术—材料科学与工程]