Technical progress on printed wired assembly using Nortel's no-lead solder assemble process

In 1996, Nortel (Northern Telecom Ltd.) produced telephone set printed wired boards with no lead in the solder. Results from this experiment indicated performance that was equal to or better than that of the standard tin-lead solder process. Following this achievement, Nortel is currently evaluating the requirements necessary to apply this technology to low volume manufacturing yields of telephones. In 1997, Nortel expanded the lead free program into other fields of board assembly technology. Testing of the technology was expanded to include: halogen-free printed wired boards; lower cost Chopped Epoxy Material (CEM3) Printed Wired Boards (PWBs); higher density wireless circuit boards (which are free of gold); back panel assembly; and finally an electronic shelf (power board). Additionally, Nortel subjected these boards to thermal cycling tests then microscopic examination of the solder joints.