科研之友
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摘要
The effects of isothermal aging on the microstructure and shear strength of Sn37Pb/Cu solder joints were investigated. Single-lap shear solder joints of eutectic Sn37Pb solder were aged for 1-10 days at 120 degrees C and 170 degrees C, respectively, and then loaded to failure in shear with a constant loading speed of 5 x 10(-3) mm/s. The growth of the interfacial Cu-Sn intermetallic compounds (IMC) layer (Cu6Sn5 + Cu3Sn) of Sn37Pb/Cu solder joints subjected to isothermal aging exhibited a linear function of the square root of aging time, indicating that the formation of Cu-Sn IMC was mainly controlled by the diffusion mechanism. And the diffusion coefficient (D) values of IMC layer were 1.07 x 10(-17) and 3.72 x 10(-17) m(2)/s for aged solder joints at 120 degrees C and 170 degrees C, respectively. Shear tests results revealed that as-reflowed solder joint had better shear strength than the aged solder joints and the shear strength of all aged solder joints decreased with increasing aging time. The presence of elongated dimple-like structures on the fracture surfaces of these as-reflowed or aged for short time solder joints were indicative of a ductile failure mode. As aging time further increased, the solder joints fractured in the mixed solder/IMC mode at the solder/IMC interface.
- 出版日期2014-8
- 单位中国电子科技集团公司第三十八研究所; 江西省科学院; 南昌大学
