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 Georgia技术研究所制造多层印刷电路板的关键问题是铜的快速而均匀的铜沉积在板条“通行”的内部表面上。 对于常规板（所有互连都是通过整个孔的）以及使用表面安装技术的董事会，镀金速度，均匀性和沉积延展性之间的权衡是，仅以降低速度，需要大型资本投资和过程中的库存成本才能实现可接受的收益。 对于未来董事会中较高纵横比的孔，对现有过程的增量修改将无法在可接受的处理速率下提供所需的统一性。 该项目包括对流体力学的基础研究和一种根本新方法来铺板高宽高比孔的质传。 关键的想法是在淹没板的整个孔中操作旋转螺丝电极（RSE）。 RSE会产生径向，方位角和轴向流，从而使孔中和内部更有效地传达大质量，而不是使用常规技术。 实验表明，所得铜沉积物的厚度比使用流行的振荡板技术实现的轴向均匀性要大得多，后者在孔中建立了时间周期性的Poiseuille流动。 还将考虑通过轴向压力梯度的流量修饰，该轴向压力梯度将被选择以给予流动逆转。 这将提供流动的相对向导部分之间的逆流传质，并抑制孔的中央部分中阳离子耗尽的边界层的形成。 这种方法将为当前正在开发的高宽高比比孔的高宽高比的改进的电镀过程的工业评估和开发奠定基础。 结果还将对在其他应用中增强热量和质量发展有影响。