Megasound acoustic agitation for enhanced copper electrodeposition in via interconnects

A Printed Circuit Board (PCB) is populated with a multitude of electro-mechanical components plus various active and passive devices such as transistors, capacitors, inductors and resistors, which enable the functionality and assembly of the PCB. Increasing the density of the components on the surface of a board enables greater functionality and use. A high density (HD) design is desirable for technology high end applications, which includes automotive, aerospace, space, defense, mobile phones, medical, networking, communications, and computerstorage. The current trend in PCB markets is low-technology, high-volumedemand and is typically supplied by low-cost, large-scale facilities inSoutheast Asia, such as China, India and Thailand. High-value, low volume PCB markets are typically supplied by smaller sized facilities in western regions such as North America and Europe, but also economically developed eastern locations such as Japan, South Korea and Taiwan [2] The UK PCB demand typically focuses on this latter market. Manufacturing developments bringing increased capability and cost savings to a factory in the UK would be highly desirable and enableincreased market competitiveness. For more than four years Merlin Circuit Technology Ltd (MCT), in Deeside, North Wales, has been working in collaboration with Heriot-Watt University (HWU), in Edinburgh, Scotland, on a UK government project funded by The Engineering and Physical Sciences Research Council (EPSRC), looking to improve HD PCB manufacturing capability through enhancements to the electrodeposition of copper using high frequency acoustic, applied within a copper plating bath. This article outlines some of the key findings from this project