Cu核微焊点液-固界面反应及剪切行为研究  

Study on liquid-solid interfacial reaction and shear behavior of Cu-cored micro solder joints

作　　者：钱帅丞 陈湜 乔媛媛 赵宁[1] QIAN Shuaicheng;CHEN Shi;QIAO Yuanyuan;ZHAO Ning(School of Materials Science and Engineering,Dalian University of Technology,Dalian 116024,Liaoning Province,China)

机构地区：[1]大连理工大学材料科学与工程学院,辽宁大连116024

出　　处：《电子元件与材料》2024年第3期367-373,共7页Electronic Components And Materials

基　　金：国家自然科学基金(52075072);山东省重点研发计划(重大科技创新工程)(2022CXGC020408);辽宁省应用基础研究计划项目(2023JH2/101300181)。

摘　　要：相较于传统Sn基焊点,Cu核焊点具备更好的导热性、导电性及力学性能。为揭示尺寸效应对Cu核焊点界面反应及剪切强度的影响,制备了不同Sn镀层厚度的Cu核焊点(Cu@Ni-Sn/Cu)。观察回流不同时间后Cu核微焊点横截面微观组织,研究了Cu核微焊点在尺寸效应下的液-固界面反应。之后对Cu核微焊点进行剪切测试,结合断口形貌,分析断裂机理。界面反应结果表明:Cu@Ni-Sn/Cu焊点在250℃回流时,Sn/Ni界面生成Ni含量较高的针状(Cu,Ni)_(6)Sn_(5)IMC,Sn/Cu界面生成Ni含量较低的层状(Cu,Ni)_(6)Sn_(5)IMC。剪切测试结果表明:随着Sn镀层厚度增加,Cu@Ni-Sn/Cu焊点的剪切强度先增大后减小。基于Sn镀层厚度对界面(Cu,Ni)_(6)Sn_(5)IMC层体积的直接影响,Sn层厚度的增加提升了焊点剪切强度。然而Cu@Ni-Sn(60μm)/Cu焊点中Cu核位置的偏移,造成剪切强度略有降低。In comparison to traditional Sn-based solder joints,Cu-cored solder joints exhibit superior thermal conductivity,electrical conductivity and mechanical properties.To elucidate the size effect on its interfacial reaction and shear strength,Cu-cored solder joints(Cu@Ni-Sn/Cu)were prepared with different Sn coating thickness.The cross-sectional microstructure were observed after different reflow durations to study the liquid-solid interfacial reaction of the Cu-cored micro solder joints under size effect.Subsequently,shear tests were conducted on the Cu-cored micro solder joints,and the fracture mechanism was analyzed by considering the fracture morphology.The interfacial reaction results indicate that when the Cu@Ni-Sn/Cu solder joints are reflowed at 250℃,needle-like(Cu,Ni)_(6)Sn_(5)IMC with higher Ni content is generated at the Sn/Ni interface,while layered(Cu,Ni)_(6)Sn_(5)IMC with lower Ni content is generated at the Sn/Cu interface.The shear test results demonstrate that with increasing Sn coating thickness,the shear strength of Cu@Ni-Sn/Cu joints increases initially and then decreases.Due to the direct influence of the Sn coating thickness on the volume of the(Cu,Ni)_(6)Sn_(5)IMC at the interface,thicker Sn layer enhances the shear strength of the solder joint.However,due to the offset of the Cu-core position in Cu@Ni-Sn(60μm)/Cu micro solder joints,the shear strength decreases slightly.

关 键 词：电子封装 Cu核焊球 液-固界面反应 金属间化合物 剪切强度 

分 类 号：TN406[电子电信—微电子学与固体电子学] TG425.1[金属学及工艺—焊接]