Effect of nano-Al2O3 reinforcement on the microstructure and reliability of Sn–3.0Ag–0.5Cu solder joints

• Autores: Zhenyu Zhao, Lei Liu, Hyun Seok Choi, Jian Cai, Qian Wang, Yuming Wang, Guisheng Zou
• Localización: Microelectronics reliability, ISSN 0026-2714, Nº. 60, 2016, págs. 126-134
• Idioma: inglés
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  • Abstract Nanoparticle reinforced lead-free solder has previously been studied by several investigators, but few studies have evaluated its reliability. In this study, resistor chip (RC) micro joints were soldered using nano-Al2O3 particle reinforced Sn–Ag–Cu solder paste. The microstructure and reliability of RC micro joints having different nano-Al2O3 contents (0, 0.25, 0.5 and 1.0 wt%) were investigated in detail. More than 40 solder joints for each condition were made and examined in order to achieve reliable data. The results indicated that nano-Al2O3 particles refined the β-Sn grain size and enlarged the eutectic area of the micro solder joints. Those nanoparticles also reduced the IMC thickness of the Ni-solder and Cu-solder interfaces. Those effects can be attributed to the poor-wetting behavior of nano-Al2O3 particles. The nano-Al2O3 reinforcement mainly enhanced the reliability of the micro solder joints, but did not affect the strength of as-soldered joints obviously. The improvement of reliability was proportional to the nano-Al2O3 content. The microstructure and fracture analysis indicated that the reinforcement and stability of Ni-IMC and Cu-IMC interfaces accounted for better reliability.