The Cambridge Method of Recycling PC Boards Spares the Landfills Editor's Note: The method of recycling PC boards described was invented by a team of researchers at the University of Cambridge, including Prof. Fray, working with Alpha Fry Ltd. and EA Technology. An international patent application, #9901586.9, has been filed for the process. By Prof. Derek J. Fray, University of Cambridge Exclusive to Chip Scale Review The supply of electronic scrap continues to increase, but there appear to be only two methods of treatment-land fills or supplying the waste to a copper smelter that is able to reclaim back the copper and precious metals. Unfortunately, in both methods, the value of the individual components is lost. Since some of the components include materials that are in short supply, such as the tantalum in capacitors, there is cause for concern. A Novel Treatment Method To address this urgent problem, a novel method for the treatment of PC boards was developed at the University of Cambridge, England. PC boards are made up of components that vary in worth, depending on their application, such as solder that connects the components to the copper circuits, precious metal contacts and the resinated fiberglass boards, which may contain bromine. The approach adopted at Cambridge was to devise a method that essentially removes the constituents sequentially. The initial steps were to develop a leachant that preferentially dissolves the solder so that the components are free to be removed from the board. Fluoroboric acid with an oxidant of Ti4+ ions was found to be highly selective for lead and tin. When saturated with lead and tin, the solder could simply be plated out and the leachant recovered by electrolysis at room temperature. The components were found to be in perfect working condition with their identification coding still in place. They can then be sorted according to usefulness, value or toxicity of the elements. Most of the work was done on lead-tin solders, but there is every indication that lead-free solders could be treated with equal success. To recover the copper and precious metals, the boards were shredded and the copper dissolved in cupric chloride or ammonical solution, and the resulting solution electrolysed to yield copper. Metals Dissolved The precious metals are dissolved in chloride solutions and, again, electrowon. All that is left after these unit operations is the shredded board, which can be used as filler in concrete. If the resinated boards contain bromine, this material can be recovered by combusting the boards to give heat and hydrogen bromide. This latter material can be captured by dissolution in caustic soda and liberated through displacement by chlorine. The only material left is the silica wool fiber. All the other components and materials offer an immediate value. Complete boards that have been shredded with their components can also be treated after the removal of the aluminum and ferrous scrap by passing the materials over rapidly rotating permanent magnets. The various lechants can then be applied to recover the valuable elements. The same process can be applied to used PC boards and to defective boards to remove a single faulty component rather than scrapping the whole board. Overall, these processes appear to offer a profitable route to the treatment of electronic scrap, allowing recycling of the components. Prof. Fray is in the Department of Materials Science and Metallurgy, University of Cambridge, England, CB2 3QZ. [djf25@cam.ac.uk]
Amkor Will Buy Fujitsu's Kagoshima Assembly Plant Tokyo-Amkor Technology Inc., Chandler, Ariz., has signed a non-binding agreement to buy Fujitsu's assembly and test plant in Kagoshima, Japan. The agreement calls for a joint venture to be formed through Amkor's acqusition of 67 percent of Fujitsu's interest in Kyushu Fujitsu Electronics (KFE) Ltd. After three years, Amkor would buy out the remaining 33 percent. KFE currently provides assembly and test to Fujitsu Ltd. and more than 20 third-party customers, using a variety of traditional and advanced packaging methods. Last year, the company reported assembly and test revenues equivalent to about U.S. $100 million. "This assembly and test venture with Fujitsu...is further evidence that Japan's semiconductor industry continues to move toward an outsourcing model," reported John Boruch, Amkor president and chief operating officer in a news release. Fujitsu's Masamichi Ogura, group president of Fujitsu's Electronic Devices Business Group, is quoted as saying, "Our proposed joint venture with Amkor will allow us to lower operating costs and capital requirements, as well as focusing on our core competencies...." Silicon Island The Fujitsu plant is located on Japan's "Silicon Island," the home of many of the country's most advanced wafer fabs. The planned venture will incorporate four buildings covering 300,000 square feet of manufacturing area. Amkor will manage the operations, including relationships with independent subcontractors. The Amkor announcement adds, "It is contemplated that all employees of Kyushu Fujitsu Electronics, working on assembly and test services, would be employed by the new joint venture company." The partners anticipate that the joint venture will become effective this quarter. [amkor.com]
Kulicke & Soffa Begins Construction in Suzhou, China In May, dignitaries gathered to mark the start of construction for Kulicke & Soffa's 13,500 square meter facility in the Suzhou-Singapore Industrial Park. Beginning next January, K&S will manufacture bonding tools, dicing blades and test interconnect products in the company's new plant, Kulicke & Soffa Suzhou Ltd., here.
Silicon Pipe, New S.V. Startup, Embraces Copper Technology San Jose-Silicon Pipe, a privately funded startup founded by a group of Silicon Valley veterans, has begun operations to develop a series of new copper-based products aimed at high-speed network technology. "Many developers are presently migrating to optical interconnection technology for their backplane, box-to-box and rack-to-rack electronic interconnects. Morever, many researchers are suggesting that short distance transmissions can be better served by copper," according to Joseph C. Fjelstad, a company executive, who was most recently a Fellow at Tessera Technologies.
Silicon Pipe's founders have discovered a way to extend the performance of copper to levels near that of optical over short distances-less than 3 meters at 15-20 Gbps, Fjelstad said. "We are now developing the technology for broadscale deployment using standard manufacturing infrastructure and specialized connectors." In addition to Fjelstad, the founders include Para Segaram, president, and Belgacem Haba, vice president of engineering. Segaram was founder and president of ASL Technology, acquired by Ramus. Haba was former manager of packaging research at Rambus. [sipipe.com] Sanyo High Technology, Universal Instruments Renew Contract Binghamton, N.Y.-Sanyo High Technology, Japan, and Universal Instruments have renewed their OEM chipshooter manufacturing agreement. The agreement calls for Sanyo to continue providing the Universal HSP chipshooter line, which is sold under Universal's name. [uic.com] |
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