微量元素Ce对Sn20Bi0.7Cu1.0Ag/Cu界面层异常生长的影响  

Abnormal Growth for Interfacial Layer in Sn20Bi0.7Cu1.0Ag/Cu Solder Joint with Different Trace Element Ce Contents

作　　者：顾鑫 白海龙[1,2] 朱堂葵 刘宝权 严继康[1] 易健宏 Gu Xin;Bai Hailong;Zhu Tangkui;Liu Baoquan;Yan jikang;Yi Jianhong(Faculty of Materials Science and Engineering Kunming,Kunming University of Science and Technology,Kunming 650093,China;Yunnan Tin Industry Tin Material Co.,Ltd.,Kunming 6502171,China;School of Electromechanical and Information Technology,Yiwu Industrial and Commercial College,Yiwu 322000,China)

机构地区：[1]昆明理工大学材料科学与工程学院,云南昆明650093 [2]云南锡业锡材有限公司,云南昆明650217 [3]义乌工商职业技术学院机电信息学院,浙江义乌322000

出　　处：《稀有金属》2022年第2期169-176,共8页Chinese Journal of Rare Metals

基　　金：云南省重大科技专项计划项目(2018ZE004,2018ZE005)资助。

摘　　要：研究了Ce元素对Sn20Bi0.7Cu1.0Ag/Cu界面层组织异常生长的抑制机制。在铜基底上制备了Sn20Bi0.7Cu1.0Ag-x Ce(x=0.01~0.20;%,质量分数)/Cu焊点。采用扫描电镜、金相显微镜观察了焊点界面的相组织结构、界面金属间化合物(IMC)层形貌,并测量了IMC层厚度。通过实验数据计算了IMC层的生长动力学参数。研究结果表明:随着IMC颗粒异常长大,周围β-Sn相开始析出Bi相,继而IMC颗粒周围Bi相富集并长大,最终IMC颗粒穿晶断裂。当Ce含量为0~0.05%时,焊点界面IMC层厚度随Ce含量增加逐渐降低,当Ce含量为0.05%~0.10%时,焊点界面IMC层厚度随Ce含量增加逐渐增加;Ce含量为0.05%时对界面IMC层生长的抑制效果最好,界面IMC层表面最平滑,界面IMC层的反应常数、扩散系数最小和临界厚度最薄,分别为1.75×10^(-11)m·s^(-1),1.52×10^(-16)m^(2)·s^(-1)和7.55μm。添加微量稀土元素Ce可以阻碍焊点界面IMC层的形成并抑制其异常长大,从而间接抑制焊点界面处Bi相的偏析与降低IMC层微裂纹的出现倾向,并改善焊点界面层形貌,使其表面变得更平滑。With the development of electronic packaging towards miniaturization,high power consumption and high integration,the heat output of chip increases significantly.Therefore,higher requirements are put forward for tin solder used in electronic packaging.In electronic packaging materials,SnAgCu(SAC)series lead-free solder has been developed for decades,which has excellent solderability and reliability.However,high melting point is always a disadvantage of SAC series solder,because it can lead to too thick intermetallic compound(IMC)layer at the initial interface of solder joint,which is not conducive to long-term service of solder joint,and requires high heat resistance of welded substrate at first.Secondly,although the addition of Bi element can effectively reduce the melting point of solder and the diffusion trend of Sn atoms in the matrix to the interface layer,so as to reduce the thickness of the interface layer and improve the reliability of solder,due to that Bi element is a strong segregation element,the addition of Bi element is the cause of solder joint peeling.After aged at 443 K for 5 days,IMC layer of SAC/Cu solder joint became thicker and Cu_(3)Sn layer appeared,which was not good for the reliability of the solder,but the addition of rare earth(RE)Ce could effectively inhibited its appearance and growth.Sn20Bi0.7Cu1.0Ag-x Ce(SBCA-Ce)(x=0.01~0.20;%,mass fraction)alloy was prepared by melting tin copper alloy,tin cerium alloy,tin block,silver block and bismuth block together and then cooled in crucible.In order to obtain the best RE Ce content,the SBCA-Ce alloy was tested with different Ce content and aging time.Sn20Bi0.7Cu1.0Ag-x Ce(x=0.01~0.20;%,mass fraction)/Cu solder joints on copper pierces were prepared.The effects of aging time and Ce content on the growth of interface layer of SBCA-Ce/Cu solder joints were studied,and the causes of cracks appearance in SBCA alloy during high temperature service were analyzed.Phases microstructure and IMC layer morphology of the SBCA-Ce/Cu interface were observed a

关 键 词：CE 金属间化合物 计算 可靠性 

分 类 号：TG425.1[金属学及工艺—焊接]