AMES, Iowa – Fifteen years ago, an environmentally-friendly solder developed by the U.S Department of Energy’s Ames Laboratory made history as the first cost-effective, broadly useable alternative to tin-lead solder, a toxic but necessary ingredient in a range of popular – and proliferating – consumer electronics.

Now lead-free solder, a tin-silver-copper alloy invented by a research team headed by Ames Lab senior metallurgist Iver Anderson, has made history for a second time: In 2011, it became the top royalty income-generating technology ever produced in the history of both Ames Lab and Iowa State University.

In earning this distinction, lead-free solder surpassed Ames Lab’s previous top royalty earner – a mass spectrometer that combines the key analytical tools of multiplexed capillary electrophoresis with inductively coupled plasma-mass spectrometry – and ISU’s longstanding record-holder: an algorithm, patented in 1972, that expedited the fax transmission process.

“As of the end of June 2011 lead-free solder generated $38.9 million in royalties, exceeding all other licensed ISU technologies,” said Nita Lovejoy, associate director of the ISU Research Foundation (ISURF) and ISU's Office of Intellectual Property and Technology Transfer. Through its contract with the DOE to operate the lab, ISU may retain rights to Ames Laboratory funded intellectual property.

The mass spectrometer and fax algorithm, by comparison, garnered $17 million and $36 million in royalties, respectively, during their patent lives, Lovejoy said.

“It’s really an honor,” Anderson said, referring to the lead-free solder accomplishment. “It’s not something you expect to happen in my profession.”

Helping Green the Tech Surge

The success of lead-free solder – essentially a metallic glue that holds and electrically connects electronic parts together – stems, in part, from its role in addressing a unique problem of recent years: the need for greater quantities of this glue to build the laptops, smartphones, tablets and other increasingly in-demand devices of our day while minimizing manufacturing costs and adverse environmental impacts, such as lead leaching from electronic waste in landfills into groundwater.

Lead-free solder’s recent achievement reflects the key role it’s playing in helping companies both efficiently and responsibly manufacture the popular electronic products that have revolutionized communication in the 21st century.

“Although the work led by Iver began as a basic research project of the DOE, it is the model example of how basic research can eventually be applied to today’s societal needs,” said Ames Laboratory director Alex King. “We congratulate Iver and his team on their success and look forward to watching lead-free solder become even more widely used.”

Currently, lead-free solder is licensed to 53 companies based in 13 countries worldwide. Among those, Chinese companies represent some of the newest licensees.

“In the last four to five years, China has become part of a new licensing trend in lead-free solder adoption,” Anderson said. “China makes a lot of the components that go into systems made in Japan and the United States. Some of that is also China accepting its role as a world leader and, as part of that, the need to respect intellectual property.”

From Slow Start to Global Standard

While it would be difficult to tell from the impressive licensing rates, and revenues, of the last several years, lead-free solder wasn’t always so sought after. Although patented in 1996, licensing was slow for almost a decade until Japan started a movement for lead-free consumer electronics in about 2000, Anderson said.

“Japan’s cities are so clustered along coastlines, and have landfill sites close to housing and schools, that they were worried about lead leaching into groundwater,” he said.

With a viable lead-free alternative and a tight-knit electronics manufacturing association that enabled a broad industry-wide shift, Anderson said the Japanese push for lead-free consumer electronics soon spilled over to other nations, including a 2006 European Union law banning lead in electronic components.

“You can mark the first big ISURF [royalty] check to the year before that,” Anderson said, “because industry has to have qualified materials in place before a law like that is passed.”

Given the international nature of the electronics industry, lead-free consumer electronics manufacturing became global by proxy, marked by a noticeable growth in lead-free solder licensing rates. Between 2008 and 2011 alone, royalties generated from lead-free licenses increased 105 percent.

Building Better Solder for New Markets and Tougher Tests

With lead-free solder now an industry standard, Anderson and Ames Lab colleague Joel Harringa, along with a succession of ISU graduate students, have been working on next-generation versions that overcome certain flaws in the original formulation – for instance, the tendency for solder joints to become brittle over time from prolonged exposure to high operating temperatures. These improvements may open new avenues for adoption.

A growing interest in lead-free products in the U.S. military also can open new markets for lead-free solder in the coming years, with corresponding new licenses that will help Anderson’s patented formulation achieve even wider acceptance for very demanding uses.

Rockwell Collins, a multinational company headquartered in Cedar Rapids, is a good example of military equipment suppliers in this category, Anderson said.

“They make a lot of avionics for military aircraft,” he said. “Rockwell Collins became seriously interested in lead-free solder technology in the last two to three years, as the military has become more specific about the impact of lead-free solder on avionics product reliability. They’re doing their due diligence on, ‘Do lead-free technologies exhibit reliability for military applications’, because reliability is the most important criteria for the military.”

For military avionics, a key critical test of lead-free solder reliability is its ability to withstand a rapid shift from extreme hot to extreme cold temperatures, according to Dave Hillman, principal materials and process engineer with Rockwell Collins.

“Thermal cycling is their toughest avionics test,” Anderson said, explaining that airplane electronics are routinely subjected to rapid transitions from temperatures as low as minus 70 F to a high of 260 F.

Just like the damaging freeze-thaw cycles that lead to rapid deterioration of road surfaces, Anderson said thermal cycling encourages cracking of solder, which is potentially deadly in an airplane. A newly modified lead-free solder alloy he recently tested in collaboration with Hillman, however, has demonstrated the ability to meet this key critical test.

The new alloy is just one of several projects Anderson is working on as he continues efforts to improve the technology and tackle other obstacles to its use – efforts that he said stem from a sincere interest in removing toxic substances from the environment.

“I feel a sense of responsibility to continue developing and improving lead-free solder technology,” Anderson said. “If there’s a problem with an alloy, I want to fix it. If there’s another challenge, I want to be involved.”

The research has been funded by DOE’s Office of Basic Energy Sciences and Office of Environmental Restoration and Waste Management (now the Office of Environmental Management), the Iowa State University Research Foundation and through Work for Others projects with Nihon-Superior Co, a licensee of the technology.