Effect of Microstructures on Turbulent Flow Mass Transfer in Through-mask Electrodeposition

摘要CTS-9706824 Vijay Modi/Columbia U对撞流系统中质量通量的准确估计对于湿法化学过程，如水洗、光致抗蚀剂显影、电沉积和电化学加工非常重要。所涉及的物理系统是一个受限的水下狭缝射流，在湍流条件下正常撞击传质表面。在MEMS器件制造中，撞击表面上的小尺度结构对流体力学和传质的影响尚不清楚。将对平齐表面以及尺寸在5到500微米之间的结构表面进行传质实验测量。结构的位置和纵横比也将有所不同。冲洗表面单个传感器将提供撞击表面上的局部传质速率。对于最小的结构尺寸，即5微米，将考虑单图案结构和多图案结构。传质测量将通过电化学方法进行，其中铁氰化物离子在一个或多个紧密排列的铂电极上以由向表面的传质控制的速度被还原。现有的有限体积程序将用于模拟不可压缩的湍流流动和传质。一个需要解决的主要问题是：对于湿法加工常见的高SC应用中的壁面附近的湍流涡流扩散率，合适的模型是什么？由于一个适用于所有湍流的单一模型不太可能出现，目前的工作将为这里感兴趣的特定流动系统开发一个模型。平坦表面的实验数据将有助于开发这样的模型。该模型将在数值求解器中实现。一旦被验证，这种模型帮助预测具有微结构的表面的传质的能力将被确立。

ABSTRACT CTS-9706824 Vijay Modi/Columbia U. Accurate estimation of mass flux in impinging flow systems is important to wet chemical processes such as water rinsing, photoresist development, electrodeposition and electrochemical machining. The physical system of interest is a confined submerged slot jet impinging normally on a mass transfer surface under turbulent flow conditions. The effect on hydrodynamics and mass transfer of small scale structures on the impingement surface, typical in MEMS device fabrication is not understood. Experimental measurements of mass transfer will be carried out for both flush surfaces as well as surfaces with structures ranging from 5 to 500 microns in size. The location and aspect ratios of the structure will be varied as well. Flush surface a single sensor will provide local mass transfer rates on the impinging surface. For the smallest structure size, i.e. 5 microns, both single and multiple patterned structures will be considered. Mass transfer measurements will be made by the electrochemical method, where ferricyanide ions are reduced on one or more closely-spaced platinum electrodes at a rate controlled by mass transfer to the surface. An existing finite volume code will be utilized for modeling the incompressible turbulent fluid flow and mass transfer. A major question that needs to be addressed is: what is the appropriate model for the turbulent eddy diffusivity near the wall at the high Sc applications common to wet processing? Since one single model that is valid for all turbulent flows are unlikely to emerge, the present effort will develop a model for the particular flow system of interest here. The flush surface experimental data will aid in developing such a model. This model will be implemented in the numerical solvers. Once validated the ability of such a model to aid predicting the mass transfer to a surface with microstructures will be established.