电流密度对Cu/Sn-9Zn/Ni焊点液-固电迁移行为的影响  

Effects of Current Density on Liquid-Solid Electromigration Behavior of Cu/Sn-9Zn/Ni Solder Joint

作　　者：陈雷达 张志杰[2] 黄明亮[3] 李宝霞[1] Chen Leida;Zhang Zhijie;Huang Mingliang;Li Baoxia(Xi’an Microelectronics Technology Institute,Xi’an 710065,China;Jiangsu University of Science and Technology,Zhenjiang 212003,China;Dalian University of Technology,Dalian 116024,China)

机构地区：[1]西安微电子技术研究所,陕西西安710065 [2]江苏科技大学,江苏镇江212003 [3]大连理工大学,辽宁大连116024

出　　处：《稀有金属材料与工程》2020年第5期1629-1636,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51801079,51671046);江苏省自然科学基金青年基金项目(BK20180987);国家重点研发计划项目(2017YFB1102900)。

摘　　要：采用同步辐射实时成像技术对比研究了不同电流密度对Cu/Sn-9Zn/Ni焊点液-固电迁移行为和界面反应的影响。结果表明,当电流密度为5.0×103 A/cm2时,无论电子方向如何,钎料中的Zn原子均定向扩散至Cu侧界面参与界面反应,导致Cu侧界面处金属间化合物(intermetallic compounds,IMC)的厚度大于Ni侧界面处IMC的厚度;而当电流密度升高至1.0×104和2.0×104 A/cm2时,钎料中的Zn原子均定向扩散至阴极界面,界面IMC的生长表现为“反极性效应”,电流密度越高界面IMC的“反极性效应”越显著。液-固电迁移过程中Cu基体消耗明显,特别是在高电流密度条件下,电子从Ni侧流向Cu侧时,Cu基体的溶解厚度与时间呈现线性关系,电流密度越高Cu基体的溶解速率越快。此外,基于焊点中原子电迁移通量Jem和化学势通量Jchem对Zn原子和Cu在不同电流密度下的迁移行为进行了研究。The interfacial reactions and diffusion behaviors of Zn atoms in Cu/Sn-9 Zn/Ni interconnects during liquid-solid electromigration(L-S EM) under a current density of 5.0×103, 1.0 × 104 and 2.0×104 A/cm2 at 230 ℃ have been in situ studied using synchrotron radiation real-time imaging technology. Zn atoms would directionally diffuse towards the Cu interface under both flowing directions of electrons with the current density of 5.0×103 A/cm2, and then take part in the interfacial reaction, resulting in the thickness of intermetallic compounds(IMC) at Cu interface thicker than that at Ni interface. While when the current density rose to 1.0×104 and 2.0×104 A/cm2, the reverse polarity effect, evidenced by the continuous growth of intermetallic compound(IMC) layer at the cathode and the thinning of the IMC layer at the anode, was resulted from the abnormal directional migration of Zn atoms toward the cathode in electric field, which was more significant at high current density. Irrespective of the flowing direction of electrons, the consumption of Cu film was obvious while that of Ni film was limited. The dissolution of anode Cu followed a linear relationship with time with current density of 1.0×104 and 2.0×104 A/cm2 and electrons flowed from the Ni to the Cu, and the consumption rate was magnitude higher at high current density. It is more damaging with electrons flowing from the Ni to the Cu than that from the Cu to the Ni. In addition, based on the electromigration flux Jem and chemical potential gradient flux Jchem the diffusion behavior of Zn and Cu atoms were analyzed.

关 键 词：Sn-9Zn焊点 电迁移 界面反应 金属间化合物 反极性效应 

分 类 号：TG115[金属学及工艺—物理冶金]