3D封装用Cu/Sn/Cu焊点的组织与剪切性能研究  

Microstructure and Shear Property of Cu/Sn/Cu Solder Joints for 3D Packaging

作　　者：魏纯纯 陈明和[1] 孙磊[1] 武永 Wei Chunchun;Chen Minghe;Sun Lei;Wu Yong(College of Mechanical&Electrical Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)

机构地区：[1]南京航空航天大学机电学院,江苏南京210016

出　　处：《稀有金属》2020年第6期603-608,共6页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51805256);江苏省研究生科研与实践创新计划项目(KYCX18_0318);南京航空航天大学博士学位论文创新与创优基金项目(BCXJ18-06)资助

摘　　要：研究了250℃温度,不同键合时间对Cu/Sn/Cu焊点的界面金属间化合物(intermetallic compound,IMC)生长行为及剪切性能的影响。结果表明:键合时间由30 min增加到120 min,Cu/Sn/Cu焊点界面IMC的厚度逐渐变厚。当键合时间为30 min时,焊点界面IMC厚度为12.8μm。随着时间增加到120 min,焊点中的液相Sn消耗殆尽,形成了全IMC。在Cu/Sn/Cu焊点中,发现焊点两端界面IMC呈现非对称生长。键合时间为30 min时,焊点界面Cu3Sn的厚度分别为1.73μm(冷端)和0.95μm(热端),冷端IMC的增长速率明显高于热端,主要原因归结于温度梯度。通过对焊点界面IMC进行电子背散射衍射(EBSD)分析,发现存在的大块晶粒组织为Cu6Sn5,而Cu3Sn的晶粒相对较小。根据横截面方向(transverse direction,TD)反极图显示,Cu6Sn5的晶粒取向多平行于[001]与[111]之间。此外,随着键合时间的增加,焊点的剪切强度不断增加,当键合时间为120 min时,焊点的剪切强度由8.5 MPa增加到18.6 MPa,焊点的断裂模式由初始的混合断裂逐渐转变为脆性断裂。The effects of different bonding times on the growth behavior and shear properties of intermetallic compounds(IMCs)at Cu/Sn/Cu solder joints were investigated.The results showed that the bonding time increased from 30 min to 120 min,and the thickness of the IMC at the Cu/Sn/Cu solder joint interface gradually became thicker.When the bonding time was 30 min,the solder joint interface IMC thickness was 12.8μm.As time increased to 120 min,the liquid phase Sn in the solder joint was depleted,forming a full IMC.In the Cu/Sn/Cu solder joints,it was found that the interface IMC exhibited asymmetric growth at both ends of the solder joint.The thickness of Cu3Sn at the solder joint interface was 1.73μm(cold end)and 0.95μm(hot end),respectively.The growth rate of IMC at the cold end was significantly higher than that at the hot end,which was mainly due to the temperature gradient.By performing electron backscattered diffraction(EBSD)analysis on the solder joint IMC,it was found that the large grain structure existed as Cu6Sn5,while the Cu3Sn crystal grains were relatively small.According to the transverse direction(TD)inverse pole figure,the grain orientation of Cu6Sn5 was more parallel between[001]and[111].In addition,as the bonding time increased,the shear strength of the solder joint increased continuously.When the bonding time was 120 min,the shear strength of the solder joint increased from 8.5 MPa to 18.6 MPa,and the fracture mode of the solder joint gradually changed from the initial mixed fracture to brittle fracture.

关 键 词：Cu/Sn/Cu焊点 界面金属间化合物 剪切强度 断裂模式 

分 类 号：TG42[金属学及工艺—焊接]