Engineering Initiation Award: Analysis of Convective Mass Transfer During Electrochemical Plating and Etching

研究摘要：本项目的目的是评估一种新的非接触电化学方法在自然对流和强制对流系统中测定传质边界层厚度的准确性和研究应用范围。该方法将电流中断后的浓度过电位转换为无因次浓度分数，将应用于铜的电镀和电溶。然后将实验数据与理论电极表面浓度衰减模型相匹配。通过将实验数据的实时尺度与理论分析的无量纲时间尺度相等来确定边界层厚度。与其他确定边界层厚度的方法相比，该技术的优点是：A)该技术可以应用于大范围的电沉积和溶解反应，b)该方法可用于分析不规则形状电极上的对流传质，c)必要的实验设备简单且便宜。本文拟对该新技术进行如下研究：A)在垂直平板铜阳极和阴极上进行自然、强制和混合自然/强制对流搅拌的理论和实验边界层分析；b)分段铜阳极和阴极边界层实验；c)在半圆柱形腔中电镀和蚀刻过程中的边界层厚度测定。

Research Summary: The objective of this project is to evaluate the accuracy and study the range of applications of a new, non- contact electrochemical method for determining mass transfer boundary-layer thickness in natural and forced convection systems. The method, which will be applied to the electroplating and electro-dissolution of copper, converts concentration overpotentials after current interruption to a dimensionless concentration fraction. The experimental data is then matched to a theoretical electrode surface concentration decay model. Boundary-layer thicknesses are determined by equating the real time scale of the experimental data and the dimensionless time scale of the theoretical analysis. The advantages of the technique over other methods of determining boundary-layer thicknesses are: a) the technique can be applied to both electro-deposition and dissolution reactions over a wide range of applied currents, b) the method can be used to analyze convective mass transfer at irregularly shaped electrodes and c) the necessary experimental apparatus is simple and inexpensive. The proposed research regarding this new technique is as follows: a) theoretical and experimental boundary-layer analyses at a vertical flat plate copper anode and cathode with natural, forced and mixed natural/forced convection stirring, b) segmented copper anode and cathode boundary-layer experiments and c) boundary-layer thickness determinations in a semi-cylindrical cavity during plating and etching.