【摘要】 研究电流密度为1.5×104A/cm2时,共晶SnBi焊点的微观组织的演变。试验过程中应用MicroviewMVC2000图像采集卡对焊点形态的变化进行实时监控。通电仅110s,焊点的局部区域开始熔化;130s后达到完全熔融的状态。结果表明:通电10min后,焊点的阳极附近形成了大量的块状Bi相,而在阴极则以细条形的Bi相为主。然而抛光后发现,阴极和阳极的微观组织保持一致,钎料基体内出现了大量的Bi的小颗粒形成的聚集,阴极界面出现了空洞。通电30min后,共晶组织的均匀分布已经被打乱。阳极附近出现了Bi的聚集,而且阳极界面的IMC层比阴极界面的IMC层厚。更多还原

【Abstract】 In this paper,microstructural evolution of eutectic SnBi solder joint with current density of 1.5×104 A/cm2 after current stressing for 10 min and 30 min respectively.Microview MVC2000 image collector was applied to monitor the microstructural evolution of the solder joint during experimental process.Local melting of the solder joint occurred after current stressing for 110 s,and then it was in molten state after current stressing for 130 s.Results indicated that after current stressing for 10min,a large number of bump-shaped Bi phases were formed near the anode and the band-shaped Bi phases were form near the cathode.However after polishing,the microstructure at the cathode and anode remained the same.Many Bi particles were formed in the solder matrix and voids appeared at the cathode interface.After current stressing for 30 min,the uniform microstructure of eutectic SnBi had been disturbed.Bi accumulation occurred at the anode,and cracks appeared in the Bi accumulation region.It should be noted that IMC layer at the anode interface was thicker that that at the cathode interface after current stressing.更多还原