论文部分内容阅读
在一定温度及电流密度下对Cu/SAC305(Sn-3.0Ag-0.5Cu)/Cu焊点进行不同加载时间的电迁移时效试验。分析了电-热耦合作用下,焊点界面IMC的生长机理及界面近区元素扩散特征。结果表明:电-热耦合作用下阳极界面IMC(金属间化合物)层厚度变化与加载时间成抛物线关系;阴极界面IMC层形貌变化显著,其厚度随加载时间的延长呈现先增厚后减薄的变化特征;焊点界面近区元素扩散分为两个阶段:初始阶段由于焊点各部分元素浓度相差悬殊,浓度梯度引起的元素扩散起主导作用,促进两极界面IMC厚度增加;扩散到一定程度后界面近区元素浓度梯度相对减小,电子风力引起的元素扩散占主导部分,促进阴极IMC分解阳极IMC形成,导致阴极IMC层厚度减薄,阳极IMC层厚度逐渐增大。
The electrotransport aging test of Cu / SAC305 (Sn-3.0Ag-0.5Cu) / Cu solder joints under different temperature and current density for different loading time was carried out. The growth mechanism of IMC at the interface of the solder joint and the element diffusion in the vicinity of the interface were analyzed under the effect of the electric-thermal coupling. The results show that the change of the thickness of IMC (intermetallic compound) layer at the interface of the anode and the electrode under the action of electro-thermal coupling has a parabolic relationship with the loading time. The morphology of the IMC layer at the cathode interface changes significantly. The thickness of the IMC layer increases firstly and then decreases with the increase of loading time The diffusion of element near the interface of solder joint is divided into two stages: the element concentration in each part of the solder joint varies greatly in the initial stage, and the element diffusion caused by the concentration gradient plays a leading role to promote the increase of the IMC thickness at the interface of the solder joint; In the near interface, the element concentration gradient decreases relatively, and the electron wind-induced element diffusion predominates, promoting the formation of cathode IMC anode IMC, leading to the reduction of cathode IMC layer thickness and the thickness of anode IMC layer.