Sn-3.5Ag/Cu界面金属间化合物的生长行为研究

The growth behaviors of intermetallic compounds between Sn-3.5Ag and Cu substrate

研究了Sn-3.5Ag无铅钎料和Cu基体在钎焊和时效过程中界面金属间化合物的形成和生长行为.结果表明,在钎焊过程中,由于钎料中存在着Cu的溶解度,界面处生成的金属间化合物存在着分解现象.因此Sn-3.5Ag/Cu界面金属间化合物层厚度与化合物层的分解有着密切关系.由于吸附作用,金属间化合物表面形成了纳米级的Ag3Sn颗粒.当钎焊接头在70,125,170℃时效时,钎焊时形成的扇贝状金属间化合物转变为层状.金属间化合物的生长厚度与时效时间的平方根呈线性关系,其生长受扩散机制控制.整个金属间化合物层和Cu6Sn5层的生长激活能分别为75.16 kJ/mol,58.59kJ/mol.

An investigation was carried on the formation and growth of imtermetallic compound （IMC） at the interface between Sn -3.5Ag lead free solder and the Cu substrate. During soldering, due to the existence of solubility of Cu, the dissolution of the IMC would occur as long as the liquid solder remains unsaturated with Cu. The result indicated that during soldering, the thickness of the IMC layer was related with its dissolution rate. According to the adsorption effect, nano - size Ag3Sn particles formed on the IMC surface. During aging at 70, 125 and 170℃ up to 1000h, the initial scollop IMC layer changes into a plane shape. The IMC thickness is linearly proportional to the square root of aging time, which reveals a diffusion - controlled mechanism during aging. The activation energies values for the growth of the total IMC layers and Cu6Sn5 IMC layer are 75.16 kJ/mol and 58.59 kJ/mol respectively.