电子组装互连接头在温度冲击载荷下的失效研究

Lead-free Solder Failure Modes under Thermal Shock Loading Condition

对微电子组装互连结构进行了温度冲击测试,对比了低银和高银两种无铅钎料的在温度冲击载荷作用下的组织变化和失效模式。结果表明:新型低银无铅钎料SA C B N 07的抗冷热冲击性能最好,焊点失效后三种材料中裂纹的扩展路径不同,SA C 305失效裂纹位于体钎料中,SA C B N 07钎料断裂位置逐渐由钎料基体转移到IM C层中,而SA C 0307断裂位于界面IM C中;钎料中B i、N i元素的加入有效地抑制了IM C的生长,相同冷热冲击时间,SA C B N 07钎料中界面金属间化合物(IM C)厚度最薄。

Thermal shock resistance performance of low-Silver Sn-Ag-Cu-Bi-Ni（SACBN07）,SAC305 and SAC0307 is tested and compared in this study. Intermetallic compounds microstructure（IMC） and mechanical performance of solder aged are investigated using nano-indentation and scanning electron microscopy. Results indicate that SACBN07 shows the best thermal shock resistance compared to two other solder. And three types of solders exhibit different crack propagation paths during thermal shock test. Crack for SAC305 initiates and propagates in the bulk solder. Crack for SACBN07 propagates from the bulk solder to IMC layer. And crack for SAC0307 is observed between IMC and copper pad. In addition,addition of Bi and Ni elements into Sn Ag Cu solder effectively suppresses the IMC growth. Under the same test condition,the layer thickness of IMCs for SACBN07 is the thinnest in three solders. The hardness variation of SACBN07 subjected to thermal shock loading is the slightest. The hardness of SACBN07,SAC305 and SAC0307 decrease 8.6%,12.5% and 28.3% respectively after thermal shock test.