纳米压痕法测量SAC305焊料的力学性能  

Characterization of mechanical properties of solder joints using nanoindentation method

作　　者：王志海[1] 钱江蓉 兰欣[2] 朱士伟 王兴华 WANG Zhihai;QIAN Jiangrong;LAN Xin;ZHU Shiwei;WANG Xinghua(The 38th Rrserach Institute of CETC,Hefei 230088,China;School of Energy and Power Engineering,Shandong University,Jinan 250061,China)

机构地区：[1]中国电子科技集团第三十八研究所,安徽合肥230088 [2]山东大学能源与动力工程学院,山东济南250061

出　　处：《电子元件与材料》2020年第6期72-78,共7页Electronic Components And Materials

基　　金：国家自然科学基金青年基金项目(11702160);山东省自然科学基金面上项目(ZR201702170418)。

摘　　要：高密度电子器件的发展使得BGA封装逐渐成为主流封装形式,焊点作为BGA封装中最脆弱的连接部位,其力学性能参数对于器件可靠性设计至关重要。鉴于焊料力学性能测试中存在尺寸效应,采用纳米压痕测试技术提取了BGA封装中广泛使用的SAC305无铅焊料的力学性能参数。由压痕过程中得到的载荷-位移曲线获得了焊料的杨氏模量、硬度和蠕变应力指数,分别为62.43 GPa,198.88 MPa和14.51。另外,采用反演法和有限元模拟结合的方式研究了焊点屈服应力和应变硬化指数与加载曲线拟合方程的关系,提出了一种能更好地反演屈服应力的公式,并由此得出SAC305焊料的屈服应力为43.9 MPa,应变硬化指数为0.05。As dense electronic devices develop,BGA package has gradually become the mainstream.The most unreliable joints in BGA package are solder joints.As a result,their mechanical properties are vital for the reliability design.Considering the size effect on the mechanical property of solder,the elasto-plastic mechanical properties of SAC305 were extracted by nanometer induration test.The Young's modulus,hardness and creep stress exponent of the lead-free solder were obtained by analyzing the load-displacement curve from experiments,which are 62.43 GPa,198.88 MPa and 14.51 respectively.Furthermore,the relationship between the welding yield stress/strain hardening index and the loading curve fitting equation was studied by combining the inversion method and finite element simulation.A more suitable formula was proposed to calculate the yield stress,by which the yield stress is 43.9 MPa and strain hardening index is 0.05.

关 键 词：BGA封装焊点 力学参数 纳米压痕技术 反演法 有限元分析 

分 类 号：TG407[金属学及工艺—焊接]