锡在Cu6Sn5金属间化合物表面的润湿行为

Wetting behavior of Cu6Sn5 IMC by molten Sn

关键词:  金属间化合物|润湿性|钎焊

Key words:  intermetallic compounds(IMCs)|wettability|soldering

摘要:

利用改良座滴法研究了高真空条件下熔融纯Sn在350 ~ 450 ℃下分别与Cu₆Sn₅和T2纯铜的润湿行为. 结果表明，表面镀金的金属间化合物基板在各试验温度下的润湿性均优于纯铜基板；金属基板表面氧化膜对润湿性的影响不容忽视；离子溅射后表面形成的金膜可以作为一种改善润湿性及控制界面IMC厚度的有效方法；润湿性改善的机制为Sn与氧化膜的化学反应，界面析出IMC或者IMC的溶解过程并非限制铺展的主要因素；铺展过程表现出线性铺展规律，可用反应产物控制模型对其进行描述，计算得到Sn/Cu₆Sn₅和Sn/Cu两体系的铺展激活能分别为20.469 kJ/mol和22.270 kJ/mol.

Abstract:

Wetting behavior between the molten Sn and Cu₆Sn₅ and Cu under the temperature 350 ~ 450 ℃ was studied using the modified sessile drop method in the high vacuum. The results show that the IMCs substrates coated with a thin Au film have the better wettability than that of Sn/Cu system under the tested temperatures. The oxide film on the surface of metallic substrate is the key factor for wetting process. The thin passivation Au film on surface after ion-sputtering can be an effective method to improve the wettability and control the IMC thickness at interface. The mechanism of wettability improvement is the reaction between Sn and the oxide film. The precipitated IMC at interface or the melt process of IMC is not the main factor for spreading. All spreading dynamics show the near-linear variation, which can be described by the reaction-limited spreading model. The calculated wetting activation energies are 20.469 kJ/mol and 22.270 kJ/mol for Sn/Cu₆Sn₅ and Sn/Cu, respectively.