电子封装跨尺度凸点结构Sn3.0Ag0.5Cu/Cu微互连焊点界面IMC生长与演化及力学行为的尺寸效应  

Size Effects of Growth and Evolution of Interfacial Intermetallic Compound and the Mechanical Behavior of Bump Structure Sn3.0Ag0.5Cu/Cu Cross-scale Joints in Electronic Packages

作　　者：周敏波[1,2] 赵星飞 陈明强[1,2] 柯常波 张新平[1,2] ZHOU Minbo;ZHAO Xingfei;CHEN Mingqiang;KE Changbo;ZHANG Xinping(School of Materials Science and Engineering,South China University of Technology,Guangzhou 510640;Guangdong Provincial Engineering R&D Center of Electronic Packaging Materials and Reliability,South China University of Technology,Guangzhou 510640)

机构地区：[1]华南理工大学材料科学与工程学院,广州510640 [2]华南理工大学广东省电子封装材料与可靠性工程技术研究中心,广州510640

出　　处：《机械工程学报》2022年第2期259-268,共10页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51775195,51405162);广东省科技计划公益研究与能力建设专项(2016A010103010);中央高校基本科研业务费(SCUT-2017ZD038)资助项目。

摘　　要：针对目前无铅电子封装中主流应用的Sn3.0Ag0.5Cu钎料,研究了其直径为600~60µm的焊球在开孔型Cu基底(焊盘)上260℃恒温回流不同时间(10~300 s)形成跨尺度凸点结构Sn3.0Ag0.5Cu/Cu微互连焊点时界面金属间化合物(IMC)的生长与演化行为,以及跨尺度微焊点的剪切性能与断裂行为。研究结果表明,焊球直径大于200µm时焊点界面IMC生长速率随其尺寸减小而增大,而焊球直径小于200μm时焊点界面IMC生长速率随焊球直径减小呈减小趋势。对微焊点界面显微组织演化的分析表明,界面IMC的粗化生长过程随回流时间延长依次经历了奥斯瓦尔德熟化生长及晶粒吸附与晶界迁移生长两个阶段,且其生长阶段的转变随焊点尺寸减小而更早发生。准静态剪切加载条件下的试验结果表明,微焊点强度随其尺寸减小而增加,而恒温回流时间增加时(10~300 s)同尺寸微焊点的剪切强度并未出现明显变化,但回流时间对大尺寸焊点剪切断裂位置有明显影响。A mainstream lead-free Sn3.0Ag0.5Cu solder with cross-scale ball diameters in the range of 600µm to 60µm was used to attach on Cu pads to form micro-bump structure Sn3.0Ag0.5Cu/Cu(SAC305/Cu)joints by reflow at 260℃for different dwelling times of 10 to 300 s.The microstructure evolution of interfacial intermetallic compound(IMC),shear strength and fracture behavior of SAC305/Cu cross-scale joints were investigated.Results show that for solder balls with diameter larger than 200µm the growth rate of interfacial IMC layer of the joints increases with the decreasing solder joint size,while decreasing with the decrease of the solder joint size for solder balls with diameter less than 200µm.Meanwhile,the coarsening growth of interfacial IMC grains exhibits two featured stages:Ostwald ripening growth and grain boundary absorption/migration growth,and the transition between two growth stages occurs earlier as the size of solder joints decreases.Under quasi-static shear loading,the shear strength of Sn3.0Ag0.5Cu/Cu joints increases with the decrease of the solder joint size.In the range of reflow time from 10 s to 300 s,the reflow time has little influence on shear strength of the joints,while showing an obvious effect on the fractural path of the joints.

关 键 词：微焊点 金属间化合物 晶粒生长 剪切性能 尺寸效应 

分 类 号：TG156[金属学及工艺—热处理]