Institute of Circuit Technology's 2014 Darlington Seminar


Reading time ( words)

I recently made the long drive up to the Northeast of England for the Institute of Circuit Technology (ICT) annual Darlington Seminar, which was held on the site of the former World War II Royal Air Force Bomber Command Station, Middleton St. George, now Durham Tees Valley Airport. ICT Technical Director Bill Wilkie introduced and moderated a diverse and thought-provoking programme, acknowledging the generous support of Faraday Circuits.

Tom_Jones.jpgFirst to speak was Tom Jones from Merlin Circuit Technology, winner of ICT's “Best Young Person’s Technical Paper” award, with an extremely professional presentation on acoustic-assisted manufacturing techniques in the PCB industry.

Megasonic agitation, an acoustic technique working at much higher frequencies than ultrasonic agitation with less-damaging cavitation effects, had been successfully employed to enhance the filling of high-aspect-ratio blind micro-vias with electrodeposited copper. Jones described current work on the effects of megasonic agitation on the filling of high-aspect-ratio through vias. Some anomalies in copper thickness had been observed, with thin areas at certain positions along the length of the hole, and it was suspected that these were consequences of overtones and harmonics causing an acoustic standing wave within the hole.

Hydrophone measurements of acoustic pressure corroborated the observed behaviour, positions of maximum pressure appearing to correlate with regions of reduced copper thickness. Modelling and simulation techniques were being used to investigate the impact on wave formation in response to changes to via size, acoustic impedance of PCB material and transducer position. Current-thieving by the transducer had caused variations in copper distribution on the PCB surface, including low current frosting and high current burning. The effects had been minimised by modifying the cell geometry, particularly moving the megasonic transducer further away from PCB, although this was a trade-off against the efficiency of agitation. In other process areas, indirect acoustic agitation with megasonics had been demonstrated to have the potential to improve pattern definition in developing and etching.

Tom_Brown.jpgIf only making circuits was easier! Tom Brown, technical manager at Holders Technology, whimsically suggested that every PCB manufacturer aspired to an easier life--all he really wanted were higher manufacturing yield, lower cost of production, and better product quality. But where to find them within the mix of materials, equipment, chemical processes, mechanical processes, and people? Some solutions were high-tech, some were highly automated, but not all depended on a high level of investment and need not be complex--indeed in certain cases a solution could lie in making things simpler.

Share

Print


Suggested Items

Benchmarking Your Process Engineering

04/29/2021 | I-Connect007 Editorial Team
Mark Thompson has been in bare board fabrication for over 30 years. He is now laying out printed circuit boards at Monsoon Solutions, a high-tech design bureau near Seattle, Washington. With Mark’s extensive hands-on knowledge of PCB manufacturing, he brings a unique perspective to PCB design. In this discussion with the I-Connect007 editorial team, Mark shares what’s important from a process engineer’s point of view, and how to stay on top of evaluating and benchmarking your manufacturing process, along with insights from his new role as a designer.

Isola Releases IS550H Material

04/26/2021 | Nolan Johnson, I-Connect007
Nolan Johnson speaks with Michael Gay of Isola and Chris Hunrath of Insulectro about the release of their new halogen-free, high-thermal reliability material, which they hope fills the gap in the market between epoxies and polyimides.

EIPC Technical Snapshot: Supply Chain and Material Price Pressures

04/26/2021 | Pete Starkey, I-Connect007
EIPC’s seventh Technical Snapshot webinar on April 14 was timely and appropriate. In the context of current supply chain issues and material price pressures facing the PCB industry, particularly in Europe, the EIPC team brought together an outstanding group of experts—each a leading authority in his field—to analyse and comment upon the areas of concern and to respond to questions raised by a capacity audience. As Alun Morgan said, “If you don’t use the European supply chain, you won’t have it anymore!”



Copyright © 2021 I-Connect007. All rights reserved.