外加稳态/非稳态电场作用下金属锡的大气腐蚀行为及机理研究

Corrosion of electronic systems has become an important problem which seriously affects the reliability of electronic devices, especially with continuously increasing electronic system integration, continuously decreasing the spatial distance of circuits and components, sharply increasing the electric field gradient, the corrosion risk of electronic systems significantly increased. This topic is intended to take tin as the research object, and the wire beam electrode (WBE) is arranged between steady state/non-steady state electric field, the aim of which is to investigate atmospheric corrosion behavior and mechanism of tin under external steady state/non-steady state electric field. The influence of external steady state/non-steady state electric field on atmospheric corrosion process of tin is investigated, the atmospheric corrosion process model of tin under external steady state/non-steady state electric field is proposed, the mechanism of atmospheric corrosion evolution process of tin under external steady state/non-steady state electric field is described, the effects of external steady state/non-steady state electric field on the dissolution, diffusion and deposition processes of tin ions that produce due to electrochemical reaction are investigated by using the electrochemical test, microstructure characterization of corrosion product film, the establishment of the potential, current and Cl- ion distribution, and the theoretical analysis. Finally, the atmospheric corrosion behavior and mechanism of tin under different electric field modes are essentially clarified. This research can not only enrich the electronic system corrosion theory and thin electrolyte layer electrochemical theory, but also lay the theoretical foundation for the safe use of electronic systems and the development of new tin atmospheric corrosion protection technology.

电子系统的腐蚀已成为严重影响电子装置可靠性的一个重要问题，特别是随着电子系统集成度不断增加，线路和器件的空间距离不断缩小，电场梯度急剧增加，导致电子系统的腐蚀风险显著增大。本项目以锡为研究对象，在外加稳态/非稳态电场之间布置丝束电极(WBE)，研究锡在叠加了外加电场作用下的大气腐蚀行为和机理。通过电化学测试、腐蚀产物膜的微观结构表征、建立丝束电极的电位、电流及Cl-离子分布，并结合理论分析，研究外加稳态/非稳态电场对锡大气腐蚀过程的影响，提出锡在外加稳态/非稳态电场作用下的大气腐蚀过程模型，描述外加稳态/非稳态电场对锡大气腐蚀演化过程的作用机制，探明外加稳态/非稳态电场对电化学反应中锡离子的溶解、扩散和沉积等过程的作用规律，从本质上揭示不同电场模式对锡大气腐蚀行为的作用机理。本研究可以丰富电子系统腐蚀理论和薄层液膜电化学理论，也为电子系统的安全使用及发展新的锡大气腐蚀防护技术奠定理论基础。

电子材料的腐蚀不仅是电子系统可靠性的关键问题，同时也是电学-电化学耦合效应下腐蚀科学的基础问题。随着电子工业的迅猛发展，电子元器件的微型化，电子元器件间的电场梯度越来越大，导致电子元器件对腐蚀更敏感。锡及其合金是重要的电子互连材料，研究其腐蚀行为及机理对微电子系统可靠性具有重要的现实意义和理论价值。本文以纯锡为对象，基于阵列电极技术，使用自制的薄液膜三电极测试装置，采用电化学方法，并结合表面分析技术研究了锡在外加电场作用下的大气腐蚀机制。主要结果如下：.1. 直流电场对锡腐蚀行为的影响。在同一直流电场中，电场正极极板附近处锡的腐蚀速率最大，处在电场中间位置锡的腐蚀速率最小。主要原因有：(1)电场正极处的液膜呈酸性，所以电场正极极板附近锡的表面腐蚀产物膜会溶解；(2)在电场作用下，具有侵蚀性的Cl-在正极极板附近聚集，加剧锡表面腐蚀产物膜的破坏；(3)腐蚀过程中产生的锡离子在电场作用下从锡表面迁出，电极表面的腐蚀产物减少。.2. 交变电场对锡腐蚀行为的影响。在交变电场中，电场显著地促进了锡的阴极过程导致开路电位正移。方波电场中的腐蚀程度比正弦交流电场更为严重，因为方波电场最大扰动电位持续时间较长。锡的腐蚀速率分别随着交变电场的频率和幅值的增加而增加。幅值一定时，频率越高，交变电场对体系的扰动作用越大，从而导致对腐蚀产物膜的破坏程度越大；频率一定时，幅值越大，产生的漏电电流越大，漏电电流会破坏锡表面腐蚀产物的完整性。交变电场中漏电电流对腐蚀速率的贡献要大于电场梯度。.3.不同电场中偏压对锡腐蚀行为的影响。同一电场中，锡的腐蚀速率随着偏压的升高而增大，这是由于偏压的升高促进了锡的阳极溶解。同一偏压下，空间电场中锡的腐蚀速率小于电场中锡的腐蚀速率。这表明漏电电流的存在促进了锡的腐蚀。同一偏压下，不同电场中锡的腐蚀速率大小顺序是方波电场>正弦波电场>直流电场>不加电场。电场中漏电电流对腐蚀速率的贡献要大于电场梯度。