The deposition of increased volumes of Cu down an interconnect through-hole via (THV) of a Printed Circuit Board (PCB) is highly desirable for the fabrication of increasing component density and PCB stacks. A quality metric, called micro-throwing power, characterises the volume of Cu that can be deposited within a THV. In this paper, we analyse the influence of 1 ± 0.05 MHz megasonic (MS) assisted agitation applied to copper (Cu) electroplating baths on the micro-throwing ability of a standard, non-filling Cu electroplating solution. Our results indicate that megasonic agitation is shown to increase the Cu deposition volume within a THV by 45% for an increase of MS pressure from 225 W to 450 W, highlighting the significance of acoustic pressure as a key parameter to control MS THV plating volume. Bulk fluid flow rate within a 500 L plating tank is shown to increase by 150% due to Eckhart acoustic streaming mechanisms, compared to existing bath agitation techniques and panel movement. From MS plating experiments and COMSOL finite element acoustic scattering simulations, transducer orientation is shown to influence plating performance, with higher-order acoustic resonant modes forming within THVs identified as the cause. Simulations indicate that higher potential acoustic energy was coupled into a 0.200 mm diameter THV cavity, width-to-length aspect ratio (ar): 8:1, than a larger cavity of diameter 0.475 mm, ar 3.4:1. The maximum acoustic energy coupled into THV cavity is observed for a wavefront propagating along the axis of the cavity entrance, indicating an ideal alignment for the MS plating setup.Copyright © 2020 Elsevier B.V. All rights reserved.
Peripheral blood hematology, plasma biochemistry, and the optimization of an immune-based assay in the brown watersnake ().
August 20, 2020
July 24, 2014
June 25, 2020
- ACC 2020The American College of Cardiology decided to cancel ACC.20/WCC due to COVID-19, which was scheduled to take place March 28-30 in Chicago. However, ACC.20/WCC Virtual Meeting continues to release cutting edge science and practice changing updates for cardiovascular professionals on demand and free through June 2020.
- ENDO: 2020ENDO 2020 Annual Conference has been canceled due to COVID-19. Here are highlights of emerging data that has still been released. Keep an eye out for ENDO Online 2020, which will take place from June 8 to 22.