纳米颗粒增强SAC0307锡膏焊点的分析

Study on solder joint of SAC0307 solder paste reinforced by nano Ag/Cu particles

研究了纳米颗粒添加对低银SAC0307锡膏焊点显微组织和力学性能的影响.结果表明,添加纳米铜颗粒的焊点钎料共晶区中岛状Cu_6Sn_5相尺寸大、且难于弥散分布,添加量超过0.3%时,Cu_6Sn_5相极易在液/气界面聚集、合并和长大,导致钎料流动性变差、锡膏中助焊剂气体难于逸出而形成气孔.而添加0.1~5.0%纳米银颗粒的焊点均无气孔产生,其焊点钎料中的Ag3Sn相尺寸小易于弥散分布,且β-Sn初晶相细化明显.随纳米银添加量的增加,焊点抗剪强度先增加后降低,0.5%添加量时抗剪强度最大、较相同条件下的SAC0307焊点提高了30.8%.

The influence of nano-particles addition on the microstructure and mechanical properties of soldering joint of low silver SAC0307 soldering paste was studied.The results show that the island-like Cu6Sn5 phase exists in a larger size and is difficult to keep dispersion in solder eutectic regions with the addition of nano-Cu.When the additive amount of nano-Cu exceeded 0.3%,the Cu6Sn5 phase was easy to accumulate,merge and grow up in the liquid/gas interface.This behavior leaded the deterioration of the flowability of solder,and produced large amount of pores because the flux gas in the solder paste is difficult to escape during the soldering process.While there is no pores in solder joints with 0.1%~5.0%nano-Ag addition.The Ag3Sn phase exists in a tiny size and diffuses distribution in these solder eutectic regions,and theβ-Sn primary crystals are refined significantly in solder joints.With the increase of nano-Ag addition,the shear strength increases firstly and then decreases.when the addition is 0.5%the shear strength is the largest,meaning the shear strength in this addition is 30.8%higher than the shear strength of solder joint the SAC0307 solder paste under the same conditions.