AuSn钎料及AuSn/Ni焊点的组织性能研究

Microstructure and Properties of AuSn Solder and AuSn/Ni Joint

摘要:

分别采用叠轧-合金化法和回流焊技术制备AuSn箔材钎料和AuSn/Ni焊点，用扫描电子显微镜及电子万能试验机研究钎焊时间对AuSn/Ni界面组织及焊点剪切性能的影响。结果表明：采用叠轧-合金化法制备的AuSn钎料的熔点和化学成分都接近Au-20Sn共晶钎料。Ni/AuSn/Ni焊点在330 ℃钎焊30 s时形成良好的层状ζ-(Au,Ni)5Sn+δ-(Au,Ni)Sn共晶组织；钎焊60 s时，AuSn/Ni界面产生薄而平直的 (Ni,Au)3Sn2金属间化合物 (IMC) 层和针状 (Ni,Au)3Sn2化合物；随着钎焊时间继续延长，(Ni,Au)3Sn2 IMC层厚度明显增加，针状 (Ni,Au)3Sn2化合物异常长大。同时，随着钎焊时间延长Ni/AuSn/Ni钎焊接头的剪切强度先增加后减小，钎焊90 s时的剪切强度达到最高12.49 MPa

Abstract:

The web AuSn solders and AuSn/Ni joints were prepared by a rolling-annealing method and reflow process, respectively. The effects of the reflow time on the microstructure and the shear properties of the AuSn/Ni joints were investigated. The results show that the molten temperature and chemical composition of the AuSn solder prepared by rolling-annealing method are close to those of the common Au-20Sn eutectic alloy solder. The AuSn/Ni joint formed a fine lamellar eutectic ζ-(Au, Ni)5Sn+δ-(Au, Ni)Sn microstructure after reflow at 330 °C for 30 s. After reflowing for 60 s, a thin and flat layer of (Ni, Au)3Sn2 intermetallic compound (IMC) was formed with some needle-like (Ni,Au)3Sn2 intermetallics. Keeping increasing the reflow time, the (Ni, Au)3Sn2 IMC layer and intermetallics grew significantly. The shear strength of AuSn/Ni joints was improved with reflow time at the beginning, up to the best shear strength of 12.49 MPa at the point of 90 s, and then went down again with further increasing the reflow time.