(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 采用回流焊技术制备AuSn20/Ni焊点，通过扫描电子显微镜(SEM)及能谱分析(EDX)研究AuSn20/Ni焊点界面反应特征，探讨退火温度和时间对AuSn20/Ni焊点显微组织和剪切强度的影响。结果表明：AuSn20/Ni焊点在300 ℃钎焊90 s后，焊料内部产生ζ′-Au5Sn+δ-AuSn共晶组织和棒状(Ni,Au)3Sn2相。焊点在150 ℃退火时，界面反应速度较慢，金属间化合物(IMC)层厚度随着退火时间延长而缓慢增大；焊点的剪切强度随退火时间延长有较小幅度下降。在200 ℃退火时，AuSn20/Ni的界面反应速度较快，焊料/Ni界面形成(Au,Ni)Sn+(Ni,Au)3Sn2复合IMC层。焊点的剪切强度随退火时间延长呈较大幅度下降。从焊点力学可靠性方面考虑，AuSn20/Ni焊点不宜在200 ℃及以上温度长时间服役。
关键字: AuSn20/Ni焊点；界面反应；金属间化合物(IMC)；剪切强度
（School of Metarials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The AuSn20/Ni solder joints were prepared by the reflow process. The effects of the aging temperature and time on the microstructure and shear strength were investigated by the scanning electron microscope (SEM) with an energy dispersive X-ray (EDX). The results show that, a fine lamellar eutectic ζ′-Au5Sn+δ-AuSn microstructure and needle-like (Ni,Au)3Sn2 intermetallics are formed at the AuSn20/Ni joint after reflow at 300 ℃ for 90 s. After aging at 150 ℃ for various times，the thickness of the IMC layer at AuSn20/Ni interface grows slightly with the aging time increasing from 150 h to 1 000 h, and the shear strength of the AuSn20/Ni joints declines accordingly. When aging at 200 ℃, the reaction rate of the AuSn20/Ni interface is faster than that when aging at 150 ℃. The thickness of the IMC layer grows rapidly with increasing the aging time while the shear strength of the joints declines almost lightly. Considering the mechanical reliability of the joints, the AuSn20/Ni joints cannot service at 200 ℃ or higher temperature for a long time.
Key words: AuSn20/Ni joints; interfacial reaction; intermetallic compound (IMC); shear strength
