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60 The PCB Magazine • January 2017 MACFEST is a multi-partner project co-funded by Innovate UK to develop an electroless nickel/ immersion palladium/immersion gold (ENIPIG) "universal surface finish" for printed circuit boards. Project partners are University of Leices- ter, MTG Research, C-Tech Innovation, A-Gas Electronic Materials, Merlin Circuit Technology and the Institute of Circuit Technology. Now in its 23rd month of 24, project progress to date has been reported in a webinar moderated by special - ist in electronics assembly technology Bob Willis. Representing the Materials and Interfaces research group at the University of Leicester, Professor Karl Ryder explained the background to the project and its key aims: to develop new high-performance solderable and wire-bond- able finishes based on deposition from ionic liq- uids, with improved coating quality and solder- ability, to give improved solder joint reliability in harsh operational environments. The process would be compatible with existing printed cir- cuit manufacturing processes, with low envi- ronmental impact and no toxic components. Professor Ryder described the nature of ionic liquids and recounted some of their many suc- cessful applications in metal finishing processes. Deep eutectic solvents were a class of ionic liq- uid of particular interest for industrial processes because of the ready availability of their constit- uents in bulk quantities. They were composed of organic cations with halide anions and com- plexing agent to make anionic complexes. Spe- cifically, a deep eutectic solvent known as Ethal- ine 200, composed of ethylene glycol and cho- line chloride in 2:1 molar ratio, had been used as the basis for the immersion deposition processes developed in the MACFEST programme. It was relatively inexpensive, had low environmental impact and offered unusual solvation proper - ties with metal salts. Additionally, it readily dis- solved metal oxides and could be very success- fully used in innovative soldering fluxes. He referred to previous successful projects associated with printed circuit finishes: ION- MET which had resulted in a low-temperature immersion silver process showing reduced sol- ENIPIG—Next Generation of PCB Surface Finish MACFEST Dissemination Webinar, December 2016 FEATURE COLUMN: EUROTECH by Pete Starkey I-CONNECT007 Bob Willis Professor Karl Ryder

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