Waking Up to Lead-free Electronics
Published: Tuesday, 5 March 2002
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by: Mamta Kailkhura
Breaking Free from Lead
As environmental concerns rise around the world, companies manufacturing semiconductors and electronics components and products are under pressure to minimize the environmental liabilities of their products and technologies. This is particularly evident in the emergence of lead-free electronics assembly as a major industry trend.
Lead (Pb) is an important material used in nearly all electronics because it meets high technology performance requirements in a cost-efficient manner. Lead, along with tin, is a critical component of solder, traditionally used in the assembly of printed circuit boards. It is also widely used in semiconductor packaging. It is estimated that approximately 90 percent of all electronic components contain some amount of lead. It is well known that lead, when accumulated in the human body, can damage the nervous system. Also, lead can leak from discarded products and poison the soil and water in the area.
Double Whammy
Due to the health and environment hazards posed by lead, the electronics industry is under pressure to find alternatives to lead in the manufacturing process and in components. The pressure for change is two-pronged. The first comes from strong legislations being passed by countries, especially in the European Union (EU). One of EU directives addressing wastes in electrical and electronic equipment (the WEEE Directive) includes a ban on lead-bearing solders that would be effective in January 2008. The directive will impact all companies selling electronic products to Europe. Apart from the ban on Pb-based solders, the directive would also require manufacturers to recycle products. This presents a stiff challenge to makers of electronic products while the final lead content turns out to be only 0.5 percent of total product weight.
In Japan, the Ministry of International Trade has drawn up plans to phase out lead. The ministry is encouraging the recycling of household electronic goods, to retrieve all the lead used. Manufacturers of household electronic appliances are already working towards producing lead-free products.
Apart from legislative necessities, market pressure is also building up. The rising environment awareness among consumers has raised expectations from the electronics sector. In Japan, electronic companies have discounted the absence of strict laws and are bringing consumer products with lead-free solders to the market. These products have witnessed considerable success in the market. Surveys done in Japan and the U.S. have shown that consumers prefer products that are perceived to be environmentally friendly.
It is interesting to note that the present impetus for lead-free electronics is coming from Europe and Japan. This is forcing U.S. companies to get ready for lead-free products. The U.S. has not been pushing for lead-free solders since initial attempts in Congress to ban lead in electronic products in the early 1990s. With the EU and Japan becoming increasingly serious on banning lead, the prospect of lead-free electronics seems very real in the U.S. The ability of U.S. companies to compete in the domestic as well as overseas markets will depend to a large extent on the pace at which they adopt lead-free technologies.
Industry Takes the Lead
For a decade now companies have been doing significant research to find an alternative to the standard eutectic tin/lead solder used in assembly processes, components, and boards. Many lead-free applications have come to the market as a result. Several electronics assembly firms have taken initiatives to form global alliances to ensure a smooth transition to lead-free products. As a result, it is expected that half of manufacturing in major electronics sectors could be lead-free by the end of 2003.
Efforts to make the transition smooth and cost-effective have already started paying off. This is especially true in Japan, were several OEMs have taken initiatives to reduce and eliminate lead in electronics. Japanese companies have also been very open to sharing their status and objectives with the rest of the industry. Listed below are some Japanese companies that are taking proactive steps to reduce and eliminate lead from their products:
Matsushita: The company pioneered the world's first portable MD player, which does not use lead in soldering for the PCB assembly of the main unit. The company is making efforts to fully eliminate lead solder by the end of 2002.
Sony: Sony has been steadily reducing the use of lead with the goal to completely eliminate lead from all of their products except for high-density packaging. The company has instructed its suppliers to provide only materials and parts that are lead-free. Starting with solders that use tin and zinc. The company's research moved to soldering materials using tin and silver, and eventually to the development of soldering materials using tin, silver, bismuth, and copper, with the focus on melting temperature and mechanical strength. In its Mid-Term Environmental Action Program, Green Management 2005, Sony intends to adopt lead-free solder for all soldering of products and all plating of component electrodes. Sony is currently promoting the introduction of an alloy composed of tin, silver, and copper.
Toshiba: Toshiba has drawn up plans to adopt lead-free soldering for the manufacture of all consumer electronics, such as PCs, televisions, DVD players, digital cameras, and others by March 2003. The company plans to not only adopt lead-free soldering in its own manufacturing sections, but also ask its suppliers to adopt a lead-free soldering process.
NEC: NEC launched the first notebook computers in the world with lead-free motherboards, manufactured with tin zinc (SnZn). The company plans to install lead-free motherboards in their PCs next. Like most of its counterparts, NEC now labels its lead-free products to distinguish them from products that contain lead.
Fujitsu: Fujitsu is reducing the use of lead in its products in a phased manner, with the goal of making all products lead-free by December 2002. This initiative includes not only components produced by Fujitsu itself, but also parts outsourced to vendors.
Hitachi: As early as 1999, Hitachi reduced their lead usage to half of the amount they used in 1997. Hitachi is pushing forward in making products lead-free for conservation of the environment. The company is studying ways to further eliminate the usage of lead in their products.
Electronic companies in Europe and the U.S. also have been preparing to eliminate lead. Intel, for example, has been vocal on its commitment to finding appropriate and cost-effective ways to reduce lead in its products. Intel is working proactively with other companies to establish standards and identify compatible technologies to support the migration away from tin-lead solder. Recently, three European majors Infineon Technologies, Philips Semiconductors, and ST Microelectronics signed a pact to set the world's first standard for defining and evaluating lead-free semiconductor devices.
Cause for Concern
Though the industry has made substantial progress towards elimination of lead from products, it still does not seem to be ready to face the impending regulations aimed at complete elimination of the use of lead. There are still a number of applications in electronic components where there are no known substitutes for lead, such as in flip chips, high temperature solder, ceramic capacitors, lead zirconium titanate, and lead glass frits. Due to the widespread use of lead, it is estimated that over 200,000 electronic products, as well as 200,000-plus sub-assemblies will be affected by regulations seeking to ban lead.
Apart from the difficulty of finding reliable substitutes, the cost of switching to these alternatives is another problem. A particularly strong fear in the U.S. is that the use of lead-free compounds in chip packages and solder would cause manufacturing costs to skyrocket, considering the investment in installing new equipment for alternative materials.
Emerging Options
The electronics industry has managed to find technologically feasible alternatives to lead in some areas, especially in soldering a process that accounts for largest usage of lead in the electronics industry. Currently, there are a number of products that can be manufactured without lead solder. Pure tin finishing seems to offer the best option in terms of cost and compatibility to existing processes. However, tin deposits tend to succumb to whiskering a spontaneous growth of single crystals after the electro-deposition. Other viable options are alloys having 95 percent tin in combination with various other metals. Some of the solder formulations that the industry has come up with include tin-gold, tin-copper, tin-silver-copper eutectic, tin-indium, and tin-bismuth. Though these solders have proved their reliability in a wide range of applications, there is still not enough data on their performance in diverse conditions for long periods.
An issue with non-lead substitutes is that they require higher manufacturing temperatures than lead compounds. This substantially increases the amount of energy used during manufacturing. Some industry-accepted lead-free alloys are expected to push soldering temperatures to 240-2600C. It is doubtful whether components can survive such high temperatures.
Thinking Ahead
With lead phase-out slated to be a reality soon, the issue is not whether companies should go lead-free or not. The issue is one of time, of being ready for a legislative and market regime which discourages electronic products and components using lead.
For companies to successfully phase-out lead may not require exotic new equipment or technology. But it will require a comprehensive process definition, proper selection of materials, and ongoing review. A successful implementation of lead-free electronics hinges on issues, such as performance and reliability of alternatives, their impact on environment, limitations posed by the nature of materials, impact on cost, etc.
With increasing emphasis on environment-friendly manufacturing processes, simplification is emerging as a vital need. This will entail extensive research, evaluation, and collaboration not only at the company and product sector level, but within the entire electronics industry.
Not Just Lead
Lead is not the only element used in the electronics industry that is not environmentally friendly. Energy consumption is also a key issue. In addition, there is a growing regulatory pressure on wastes from electrical and electronic equipment, mainly in Europe and Japan. Electronic equipment is one of the largest known sources of heavy metals and organic pollutants in the waste stream. With consumers and government putting on green caps, the industry has to find ways to reduce chemical risks and use of natural resources.
Another issue is the waste generated by discarded electronic equipment. Due to rising sales and rapid obsolescence, electronic goods are being discarded at an alarming pace. So companies have to explore new processes to treat such equipment at end of life.
Several companies in Europe and Asia are already implementing producer responsibility programs in response to government regulations. Some companies take back used equipment, such as computers, than recycle or donate them to nonprofit organizations or schools. Other used equipment resurfaces at swap meets, recycling centers, or second-hand stores. However, a lot needs to be done as most used equipment still goes as landfill.
It's Time to Go Green
It is evident that the emerging rules of the market favor companies stamped with the environment-friendly label. Companies oblivious to the green writing on the wall may turn out to be the laggards of the future. The industry is in the midst of changes that are pushing it into an era of lead-free electronics, take-back of products, and end-of-life treatment plans for those products. It's time to play the green card!
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