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Get a Jump on the Lead Ban
December 31, 1969 |Estimated reading time: 8 minutes
by Christopher Rhodes
The inside tract on what to expect over the coming years.
Exactly when will the European Union (EU) ban lead in electronics? 2004? 2006? 2009?
According to the proposed EU directive on Waste from Electrical and Electronic Equipment (WEEE), the deadline will be 2004. The European Federation of Interconnection & Packaging (EFIP) petitioned the European Commission (EC) to delay any lead ban until at least 2009.
Inside information suggests that the ban will be delayed it is not known for how long. There are also signs that the ban may not be a ban at all. The EU may propose reducing lead usage instead of banning lead altogether.
Asking when lead will be banned may be the wrong question. Perhaps a better question is, "What does it matter?" Given the various proposals that have popped up in recent years around the world, the outlook seems fairly clear: Lead in electronics will disappear.
Although there is a dearth of data indicating that lead in electronics waste poses any substantial environmental threat or health hazard, IPC nonetheless believes that public, political and market pressures will eventually drive lead out of electronics. It may happen in less than five years or it may take 10 or more years, but eventually, electronics will not contain lead.
IPC and many other organizations and companies in the electronics industry are stepping up research into alternatives for lead surface finishes, lead solder and other lead uses.
Current Technical CapabilitiesIf lead is banned sooner rather than later, are drop-in replacements ready?
According to Martin Goosey of Shipley Europe, "The general consensus is that there is, as of yet, no realistic alternative to the familiar tin-lead solders we currently use and no alternative will provide the universal solution the industry needs." Brian Haken, executive director of the Printed Circuit Interconnection Federation, echoed that sentiment: "I remain unconvinced that a satisfactory solution is in sight at the present time."
However, many lead-free alloys are available for a wide range of applications. The most promising alloys for general purpose soldering appear to be Sn/Ag/Cu systems; work is also being performed on alloys containing bismuth, zinc, indium, antimony, nickel and germanium.
Some common issues with lead-free solders include:
- Most have melting points higher than Sn60/Pb40, raising compatibility problems with materials, components and equipment
- Higher temperatures may necessitate higher Tg materials and may damage plastic integrated circuits (IC)
- Because lead contamination from lead-coated components can cause problems, the availability of components with lead-free finishes is a concern
- Fillet-lifting may be a problem, especially in wave soldering
- Lead-free soldering generally has a narrower process window
- New fluxes and new cleaning processes may be needed
- New criteria for inspection (X-ray and visual) may be needed
- Rework and repair may cause problems, especially if the repair is done with leaded solder.
Despite these concerns, most experts feel that there are no insurmountable technical barriers to implementing lead-free solders. In fact, the major barriers are not really technical at all. According to the Environmentally Friendly Packaging Specialty Committee in Japan, the major barrier to implementation is a "three-way deadlock" between the component manufacturers, the solder suppliers and the electronic equipment manufacturers.
Solder manufacturers are reluctant to invest heavily in R&D without sufficient market demand from the equipment manufacturers. Similarly, component manufacturers are slow to develop new lead-free component technologies without sufficient markets. Electronic equipment manufacturers do not feel that lead-free solders and components for lead-free solders are sufficiently developed for practical, widespread use.
Other barriers to implementation include insufficient information on the issue, the alternatives, and the necessary process and equipment modifications. Larger OEMs are further ahead in understanding the various technological issues, the timelines for change and the implications of going lead-free for other aspects of electronic equipment. They are also more in touch with consumer demand for green products.
By contrast, smaller OEMs and contract manufacturers (CM) lag in their awareness of the issues and alternatives. Although most every company is aware of the issue and the proposed EU lead ban, their knowledge is not detailed with respect to when the proposed ban might go into effect, what various lead-free solders are available, and how going lead-free will affect other manufacturing and supply activities.
When it comes to lead-free printed circuit board (PCB) surface finishes, the situation is somewhat different. Virtually all board manufacturers would love to remove lead entirely from their facilities. However, as long as CM, OEM and military specifications call for tin-lead finishes, PCB manufacturers may not be anxious to invest significant capital into new lead-free finish processes and equipment.
To help support the move to lead-free finishes, the IPC is working voluntarily with the U.S. Environmental Protection Agency (EPA) on evaluating alternatives to hot-air solder-leveling (HASL) surface finishes through the Design for the Environment (DfE) Alternative Surface Finishes (ASF) Project. When completed, the results of this project will help the industry implement more lead-free surface finishes.
The IPC DfE ASF Project was started in October 1996 to evaluate alternative surface finish technologies and compare them to HASL. This ASF Project is testing various surface finishes for performance, cost, ease of implementation, environmental and health risks, and comparing these finishes to HASL performance.
Besides HASL, five alternative surface finishes are being evaluated: organic solder protectorate, immersion tin, immersion silver, electroless nickel/immersion gold and electroless palladium/electroless nickel/immersion gold.
Data collected through the DfE ASF Project will complement earlier studies
conducted by the Circuit Card Assembly and Materials Task Force (CCAMTF) and the National Center for Manufacturing Sciences (NCMS).
Ongoing ResearchEurope and Japan presently lead the world in research on lead-free solders. More than 10 R&D projects are underway in Europe, including partners such as GEC, Nortel, Multicore Solders, Phillips, Siemens, Witmetaal, Volvo and Motorola. These projects include:
- Lead-free soldering
- Modeling of solder joint reliability
- Fundamental characterization of lead-free systems
- Wettability of surfaces with lead-free solders
- Integrity of lead-free solders
- Predicting new alloy systems
- Improved design life with lead-free solders.
In Japan, the Japan Institute of Electronics Packaging completed a broad consortium project on lead-free soldering in 1996. Many Japanese universities are involved in R&D on lead-free solders and soldering. The Japan Welding Society, the Japanese Society of Mechanics and numerous corporations are conducting other projects.
U.S. research has been limited. NCMS completed a consortium project in 1996. While three alloys were found to be feasible, NCMS found no viable drop-in replacement for lead.
Of course, many corporations are also carrying out research on their own or in limited partnerships. Nortel Networks has produced about 500 lead-free Meridian phones at different sites in North America and Europe using a Sn/Cu alloy system and numerous component finishes. Motorola is trying lead-free alloys in engine management systems, as is Ford. TI undertook a study of lead-free solders and reached the conclusion that "it is now possible to achieve a totally Pb-free solder joint."
These research projects support the conclusion that the technical barriers to lead-free soldering are surmountable in a reasonable time frame.
Bring the Players TogetherBecause of the global interest in this subject, IPC is sponsoring an International Summit on Lead-free Electronics Assemblies on October 26 to 28, 1999, in Minneapolis.
IPC has received worldwide support for the conference, and several other organizations, including NEMI, NIST, ITRI and HDPUG, have committed themselves to endorsing the event. The conference will be split into four sessions: alloys and adhesives, components, PCB finishes and company case histories.
At those sessions, conference attendees can get a first-hand look at the lead-free situation, its effect on other companies and how they can prepare for the impending change. At this time, tentative commitments for paper presentations include:
- Carol Handwerker, NIST, will give a presentation on the status of lead removal, what is going on in Japan and how it will affect the U.S. PCB industry. Handwerker has spent several years tracking the lead removal process as it has continued to grow in Japan and the United States.
- Kay Nimmo of the International Tin Research Institute will give a presentation on the use of lead in many regions of the world. This paper will describe some of the drivers toward a reduction in lead use and will comment on the third draft of the EC directive that is expected shortly before the conference.
- Andy Mackie, Praxair, will give a presentation on reflow atmospheres and lead-free soldering. This paper provides a basic introduction to the effects of temperature and oxygen content of the atmosphere on the degree of oxidation of various metal surfaces relevant to electronics assembly.
- TDK, one of the largest component manufacturers in Japan, has committed to presenting a paper on lead-free piezoelectric materials.
- NEMI will present data from a survey to be conducted this summer to determine manufacturability and reliability problems in components with increased soldering temperatures anticipated in the short-term implementation of lead-free solder. The types of components include all surface mount, through-hole, substrates and assembly materials such as fluxes, coatings, and passivations. Due to their temperature sensitivity and seal integrity, electrolytic capacitors are of particular interest.
Following the technical presentations, the attendees (audience and presenters) will split into breakout sessions. From the breakout sessions, the attendees will create the IPC Roadmap for the Removal of Lead from Electronics Assemblies.
Everyone is invited and encouraged to attend the International Summit on Lead-free Electronics Assemblies. For more information on this summit, please contact Chris Jorgensen at (847) 790-5328, fax (847) 509-9798 or e-mail jorgch@ipc.org. For more information on the roadmap, please contact David Bergman at (847) 790-5340, fax (847) 509-9798 or e-mail bergda@ipc.org.
CHRISTOPHER RHODES is the director of public policy for the IPC Association Connecting Electronics Industries, 2215 Sanders Road, Northbrook, IL 60062-6135; (847) 509-9700, ext. 306; Fax: (847) 509-9798; E-mail: rhodch@ipc.org.