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26 SMT Magazine • October 2014 FEATurE As first brush, the title's suggestion that sol- der can be eliminated from the electronics as- sembly process may appear absurd. Everyone related in any way to electronics manufacturing industry knows that solder is the universally ac- cepted way of connecting components to print- ed circuits in electronic assemblies. Thus, the fact that many seasoned and knowledgeable people in the electronics industry might scoff at the notion that solder can be eliminated comes both without surprise and a certain amount of resignation. However, in reality, solderless interconnec- tions are all around us. Many interconnections in electronic products, both permanent an in- termittent, are made without the use of solder. by Joe Fjelstad vErdAnT ELECTrOniCS Assembly and the Quest for Solder Alloy-Free Electronics (SAFE) Some noteworthy examples include press-fit interconnection of backplane connectors, sep- arable interference interconnection between daughter cards and mother boards, wire wrap techniques to connect between component or connector pins, wire bonding used to intercon- nect chips to packages, resistance welding, and conductive adhesives. However, perhaps the most ubiquitous and yet least acknowledged form of solderless interconnections, are the tril- lions of electrolessly and electrolytically cop- per plated electrical and electronics intercon- nections made every year in printed circuits to make interconnections on multilayer circuits and more recently, for the circuits and inter- connection of semiconductor chips. The fundamental idea behind solderless as- sembly based on plating is simple enough. It is perhaps best illustrated by contrasting it with the