FeNi合金UBM圆片级封装焊点剪切力研究  

Study of the Solder Bump Shear Strength of WLP with FeNi Alloy UBM

作　　者：奚嘉[1] 陈妙[1] 肖斐[1] 龙欣江[2,3] 张黎 赖志明 

机构地区：[1]复旦大学材料科学系,上海200433 [2]江阴长电先进封装有限公司,江苏江阴214431 [3]东南大学MEMS教育部重点实验室,南京210096

出　　处：《半导体技术》2015年第9期692-698,共7页Semiconductor Technology

基　　金：国家科技重大专项资助项目(2011ZX02602)

摘　　要：Fe Ni合金与无铅焊料反应速率低,生成的金属间化合物(IMC)较薄,有望作为圆片级封装(WLP)凸点下金属(UBM)层材料。对两种Fe Ni UBM以及一种Cu UBM圆片级封装样品进行回流、湿热以及预处理实验,并通过推球的方法,对其焊点进行剪切测试。通过断面与截面分析,研究其在不同处理条件下的金属间化合物生长情况,分析其断裂模式。结果表明,Fe Ni UBM焊点剪切力高于Cu UBM。Fe47Ni UBM与焊料反应生成的金属间化合物较薄,对于剪切力影响较小,而Fe64Ni UBM与焊料反应生成离散的Cu Ni Sn金属间化合物,对于其焊点强度有提高作用,Cu UBM与焊料反应生成较厚的金属间化合物,会明显降低焊点的剪切力。断面分析表明,Cu UBM会随焊球发生断裂,其强度明显小于Fe Ni UBM。Fe Ni alloy has low interfacial reaction rate with Pb-free solder and forms thin intermetallic compounds（ IMC） during reflow,which might be used as the under bump metallization（ UBM） in wafer level package（ WLP）. The reflow,temperature / humidity and preconditioning experiment of two types of Fe Ni UBM and a Cu UBM wafer level package samples were carried out. The solder ball shear strength was tested by using the method of ball push. Through the cross-section analysis and fracture surface observations,IMC growth and fracture mode of the samples under different treatment conditions were investigated. The results show that the shear strength of Fe Ni UBM bump is higher than that of Cu UBM.The IMC between Fe47 Ni and solder was very thin,which had little influence on the shear strength of the bump. While the discrete IMC of Cu Ni Sn near Fe64 Ni UBM can increase the shear strength of the bump.In addition,the thick IMC on Cu UBM can obviously decrease the shear strength. The fracture surface analysis shows that the Cu UBM is more likely to crack during shear tests,therefore the strength of Cu UBM is lower than that of Fe Ni UBM.

关 键 词：圆片级封装(WLP) 凸点下金属(UBM) FeNi合金 剪切力 金属间化合物(IMC) 

分 类 号：TN405[电子电信—微电子学与固体电子学]