About the Printed Wiring Board Project
The DfE Printed Wiring Board (PWB) Partnership fostered open and active participation in addressing environmental challenges faced by the PWB industry. The project also identified, evaluated, and disseminated information on viable pollution prevention opportunities in the industry. This voluntary, non-regulatory project sought to encourage companies to implement cleaner technologies to improve the environmental performance and competitiveness of the PWB industry. Toward this end, the DfE partners, including the international PWB trade association, IPC-Association Connecting Electronics Industries, worked to develop and analyze technical information on pollution prevention technologies that reduce risks to human health and the environment, hazardous waste generation, compliance costs, and chemical and natural resource use.
Making Holes Conductive
In the project's first major study, the University of Tennessee's Center for Clean Products and Clean Technologies, under a grant from EPA, collaborated with the PWB industry to verify the performance, environmental benefits, and costs of seven existing and emerging "making holes conductive" (MHC) technologies. The results of the study were compiled into a Cleaner Technologies Substitutes Assessment (CTSA). The MHC CTSA includes the following elements: chemical and process description, health and environmental effects, chemical fate, workplace and general population exposures, environmental releases, risk characterization, performance, cost analysis, process safety, domestic and international markets, regulatory status, energy impacts, resource conservation, pollution prevention and control opportunities, and social benefits and costs. The draft MHC CTSA was posted on this site and made available for review in August 1997. The final CTSA was published in August 1998 and is posted on this site.
The PWB Partnership also conducted a second CTSA to evaluate existing and emerging PWB surface finishes.
The partners evaluated lead-free alternatives to the hot air solder leveling (HASL) process. The goal of this second CTSA was to identify surface finish technologies that perform competitively, are cost-effective, and pose fewer potential environmental and health risks. The most commonly used PWB finishing technologies are HASL and electroplated tin-lead. These technologies pose potential health and environmental risks due to the use of lead, and the HASL process also generates significant quantities of excess solder that must be recycled. There are several surface finishes viewed as viable alternatives to HASL and electroplated tin-lead.
The technologies evaluated in the Surface Finishes Project include: organic solder protectorates, immersion silver, immersion tin, electroless nickel/immersion gold, electroless nickel/electroless palladium/immersion gold, and the HASL process, which was tested as the baseline technology.
As with the MHC CTSA, EPA expects that the results of the Surface Finishes CTSA will encourage PWB manufacturers to adopt cleaner, more environmentally benign and cost-effective processes, which will improve their competitiveness in the international marketplace and benefit the environment.