Fluid Mechanics and Mass Transfer of the Rotating Screw Electrode Process for Plating Through-Holes in Multilayered Printed Circuit Boards.

多层印刷电路板电镀通孔旋转螺杆电极工艺的流体力学和质量传递。

• 批准号: 9528642
• 负责人: Ari Glezer
• 金额: $ 13.97万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-15 至 2001-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9528642&HistoricalAwards=false
• 关键词: Fluid; Mechanics; Mass; Transfer; Rotating

ABSTRACT CTS-9528642 GLEZER GEORGIA INSTITUTE OF TECHNOLOGY A key problem in manufacture of multi-layered printed circuit boards is rapid and uniform deposition of copper on inner surfaces of plated "through-holes." For conventional boards (in which all interconnects are by means of through- holes) as well as boards also using surface-mount technology, the trade-off between plating speed, uniformity, and deposit ductility is such that acceptable yields are achievable only at the cost of reduced speed, requiring large capital investment and in-process inventory costs. For holes of higher aspect ratio in future boards, incremental modification of the existing process will be incapable of providing the desired uniformity at acceptable processing rates. This project consists of a fundamental study of the fluid mechanics and mass transfer of a radically new approach to plating high aspect ratio holes. The key idea is to operate rotating screw electrodes (RSEs) in through-holes of submerged boards. The RSE generates radial, azimuthal, and axial flow, leading to much more effective mass transfer into and within the hole than is possible using conventional technology. Experiment shows the thickness of the resulting copper deposit has much greater axial uniformity than is achieved using the popular oscillating board technique, which establishes time-periodic Poiseuille flow in the hole. Flow modification by an axial pressure gradient, whose magnitude will be chosen to give flow reversal, will also be considered. This will provide countercurrent mass transfer between oppositely directed portions of the flow and suppress formation of cation-depleted boundary layers in the central section of the hole. This approach will lay the foundation for industrial evaluation and development of an improved plating process for high aspect ratio through-holes currently being developed. The results will also have implications for enhancing heat and mass tra nsfer in other applications.

摘要CTS-9528642 GLEZER格鲁吉亚Institute OF Technology 多层印刷电路板制造中的一个关键问题是铜在电镀“通孔”内表面上的快速和均匀沉积。“对于传统的电路板（其中所有互连都是通过通孔）以及也使用表面安装技术的电路板，电镀速度、均匀性和存款延展性之间的权衡使得仅以降低速度为代价才能实现可接受的产率，这需要大量的资本投资和过程中库存成本。 对于未来电路板中高纵横比的孔，现有工艺的增量修改将不能以可接受的处理速率提供所需的均匀性。 该项目包括一个基本的研究流体力学和传质的一个全新的方法来电镀高深宽比孔。 其关键思想是在浸没板的通孔中操作旋转螺旋电极（RSE）。 RSE产生径向、方位角和轴向流动，导致比使用常规技术可能的更有效的质量传递到孔中和孔内。 实验表明，所得到的铜存款的厚度具有更大的轴向均匀性比使用流行的振荡板技术，建立时间周期性Poillille流在孔中实现。 还将考虑通过轴向压力梯度进行的流动修正，其大小将被选择以提供流动逆转。 这将在流的相反方向部分之间提供逆流质量传递，并抑制在孔的中心部分中形成阳离子耗尽的边界层。 这种方法将为目前正在开发的高纵横比通孔的改进电镀工艺的工业评估和开发奠定基础。 这些结果也将对其他应用中的传热传质的增强产生影响。