Sn/Cu互连体系界面金属间化合物Cu_6Sn_5演化和生长动力学的相场法模拟  

PHASE FIELD SIMULATION ON MICROSTRUCTURE EVOLUTION AND GROWTH KINETICS OF Cu_6Sn_5 INTERMETALLIC COMPOUND DURING EARLY INTERFACIAL REACTION IN Sn/Cu SOLDERING SYSTEM

作　　者：柯常波[1,2] 周敏波[2] 张新平[2] 

机构地区：[1]华南理工大学机械与汽车工程学院,广州510640 [2]华南理工大学材料科学与工程学院,广州510640

出　　处：《金属学报》2014年第3期294-304,共11页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目51275178和51205135;高等学校博士点科研基金项目20110172110003;中央高校基本科研业务费项目2013ZM0026资助~~

摘　　要：运用多相场模型模拟了Sn/Cu互连体系中晶界扩散系数DGB及界面初生金属间化合物(IMC)相(η相)与液相Sn(L相)间界面能σηL对界面Cu6Sn5组织演化和生长动力学行为的影响.研究表明,界面IMC层Cu6Sn5晶粒以紧密排列的扇贝状形貌存在,其扇贝状形貌同时受DGB和σηL的竞争性影响.IMC的生长过程由3阶段组成:Cu6Sn5晶粒快速生长铺满Cu基底阶段、Cu6Sn5晶粒转变为扇贝状形貌的过渡阶段以及Cu6Sn5层增厚和晶粒粗化同时进行的正常生长阶段.IMC层厚度随DGB增大而增加,随σηL增大而减小;而Cu6Sn5晶粒的平均横向粒径随DGB增大而减小,随σηL增大而增加.界面Cu6Sn5层厚度和晶粒横向粒径随反应时间呈指数规律变化,采用较大DGB和晶界能σGB=2σηL获得的生长指数符合理想的固/液界面反应的生长过程.In the continuous pursuit of miniaturization, multifunction and high-reliability of electronic products and devices, the packing density has been increasing and the dimension of solder joints has been scaling down. In electronic packaging, during the soldering process being employed to Sn-based solders, an intermetallic compound （IMC） layer is formed between molten solder and pad （or under bump metallization, UBM）, whose morphology and thickness as well as growth kinetics play an important role in controlling the service performance of the solder joints, in particular for solder interconnects with the decreasing size where the interfacial IMC layer takes up a high volume fraction in the solder joint. Thus, characterizing the morphology change and growth kinetics of interfacial IMC layer is very important to optimize the soldering process and evaluate the reliability of solder interconnects. In this study, a multi-phase-field model is applied to intensively account for the effect of grain boundary diffusion coefficient （DoB） and IMC/liquid interfacial energy （σηL） on the morphology evolution and and growth kinetics of IMC. The simulation results show that Cu6 Sn5 grains grow up and contact with each other exhibiting a scallop-like morphology which can be influenced by both the grain boundary diffusion coefficient and IMC/liquid interracial energy. The IMC growth process exhibits three stages, including the initial stage associated with Cu6Sn5 grain broadening followed by the transition stage characterized by scallop shape formation and the last normal growth stage dominated by IMC layer thickening and concurrent Cu6Sn5 grain coarsening. It is also found that the IMC layer thickness increases with .grain boundary diffusion coefficient but decreases with IMC/liquid interracial energy, while the scallop average width decreases with grain boundary diffusion coefficient and increases with IMC/liquid interracial energy. The relationships between IMC layer thickness/width and reaction time can be well f

关 键 词：金属间化合物 生长动力学 组织演化 界面反应 相场模拟 

分 类 号：TG113[金属学及工艺—物理冶金]