Welcome to EFSOT - Next Generation Environment-Friendly Soldering Technologies

EFSOT ? Just Lead-free is Not Yet Green!

The EU banned lead from electronics to reduce the toxicity of waste of electric and electronic equipment, and the Japanese industry for years has been successfully promoting lead-free soldering. In the 3 year integrated research project EFSOT (Next Generation Environment-Friendly Soldering Technology), 13 Japanese, 8 European and 4 Korean partners from industry and institutes cooperated to find technically advanced, reliable and environment friendly solutions for lead-free soldering. In Europe, the project has been startet since February 2002 and ended in December 2005.
In Europe, the partners are TU Berlin (Germany) as EU-coordinator, Philips and Pré Consultants (The Netherlands), TCL Thomson Electronics and Avantec (France), TT Electronics/ AB Mikroelektronik (Austria), Fundación Gaiker and Indumetal Recycling (Spain).

Advancement of Lead-free Technology
Reliability, in particular for fine pitch applications, is a major concern in the context of leadfree soldering. The European partners developed a new SnAgCu-type fine pitch solder paste, which is robust and easy to use in a broad field of applications ranging from consumer to automotive electronics. The partners found root causes of whiskering on tin finishes and contributed a proposal for an international standard whisker test, which is under discussion in the standardization committees.

A new reliability testing method for lead-free fine pitch solder joints takes into account influence of the solder joint geometries and different solder/finish combinations in the solder joint. It enhances the validity and real-condition proximity of the test results.

Finally, the European partners worked out models for reliable PWB assembly as well as requirements and new properties of new reflow oven equipment to further increase the reliability of the solder joints.

Environment and Resources
The researchers confirmed that waste of electric and electronic equipment with lead-free soldered printed wiring boards actually is less toxic for humans. However, there is also a price to pay for this benefit. The higher melting points of most lead-free solders increase the energy consumption in manufacturing, and the lead-free solders apply scarce metals, which also cause higher energy consumption and more emissions in mining and smelting.

Generally, the electronics industry should minimize the use of noble and platinum group metals for environmental and cost reasons. The use of tin-silver-copper type solders with a maximum of 3 % of silver for reflow and wave soldering is preferable to the 4 % silver solders. For wave soldering, tin-copper type solders are recommended. Industry should put further research into the application of low-melting solders, e. g. tin-zinc (-bismuth) type, as a prospective lead-free solder. These solders would reduce the energy consumption and thermal stress on electronic components during manufacturing. Electronics manufacturers should consider whether new soldering ovens can increase the energy efficiency, and oven manufacturers must improve the efficiency of this equipment. Solders with antimony, e. g. tin-antimony, and indium containing solders should be avoided.
Antimony proved to be more toxic than lead, and the general use of indium would result in resource problems, as the stocks are small and recyclers do hardly recycle it. The use of bismuth, in particular in SnBi type solders may increase the demand for an additional 30 % of the current global mining production. Fears of resource shortages, however, could be dispelled. The researchers could show that the use of bismuth from wastes of lead-mining can easily cover the additional demand.

Recycling
The use of scarce metals like silver and tin requires stimulating the collection and recycling of waste of electric and electronic equipment. Although the treatment and recycling ability of the respective industry are high in Europe, especially the nowadays low recycling rates of tin call for more effective recycling technologies for solders, e. g. solder recycling from printed wiring boards. Various such alternatives to obtain lead-free solder concentrates from postconsume printed wiring boards were therefore investigated in EFSOT.

EFSOT ? A Framework for Future Decisions
Governments and the metal branch should stimulate green mining initiatives as the mining of metals is a major source of environmental impacts in lead-free soldering. Such measures would contribute to keep the profit of less toxic waste of electric and electronic equipment and reduce the price industry and customers have to pay for lead-free electronics.

The integrated approaches and methodologies developed in EFSOT ? technology AND environment, resources, recycling - build a strong framework for industry to innovate materials and processes. The international researchers invite legislators to profit from this knowledge for future decisions about material bans.


EFSOT thus can offer advanced technological solutions for environment-friendly, sustainable lead-free soldering. More information you get from this informative flyer (click here) , this European press release or in this website.
In the EU, EFSOT was funded by the European Community within the FP5 GROWTH Programme under the contract number G1RD-CT-2002-00838.