News
The National Electronics Manufacturing Initiative's (NEMI, Herndon, VA) Tin Whisker User Group has released a draft proposal of tin whisker acceptance test requirements. As part of its efforts to help suppliers and users minimize the exposure to problems associated with tin whiskers, the group has developed the document to provide testing requirements and acceptance criteria for evaluating devices with tin finishes in high-reliability applications.
As the electronics industry moves toward lead-free assemblies, a simple manufacturing solution is to use pure tin, or alloys with high tin content, as coatings on lead-frames. However, tin is known to be susceptible to the formation of needle-like protrusions, or whiskers, and tin whiskers are a reliability concern. They can cause electrical shorts, disruption of moving parts or degraded RF/high-speed performance. Tin whiskers may grow between adjacent conductors of different potentials and cause either a transient short circuit if the whisker is burned open, or a permanent short if the whisker remains intact. At shorter lengths, whiskers may create a stub-type effect that degrades performance of high-speed/high-frequency circuits. Additionally, whiskers can potentially break loose and, as debris, cause mechanical or other electrical problems.
"System developers face two key problems," said Joe Smetana, principle engineer, advanced technology for Alcatel and chair of the NEMI Tin Whisker User Group. "First, there is no scientific consensus on whisker formation and growth fundamentals, despite five decades of research. Second, there is no standard set of tests that can accelerate whisker formation and growth and relate these tests to field conditions with any reasonable degree of certainty. These issues make it difficult for developers to safely specify tin-based lead-free finishes for components used in their products, particularly those concerned with high-reliability or design life of more than five years."
NEMI has previously published recommendations for test conditions for evaluating tin whisker growth and for mitigation practices to help prevent whisker formation. The latest publication combines practices established by the previous documents and adds information such as test lengths, failure criteria, number of parts and additional bias voltage testing. It provides guidelines for post finishing inspection and preconditioning; outlines a flowchart for acceptance requirements; provides a framework for a qualification test report; and defines requirements for process controls and periodic testing.
The Tin Whisker User Group has scheduled a meeting on June 2, in conjunction with the IEEE Electronic Components and Technology Conference (ECTC), in Las Vegas, NV. The group will review the proposed test requirements with suppliers and solicit feedback on the practicality of implementing the various recommended mitigation and testing approaches. Supplier inputs during the meeting will be considered by the User Group for possible modifications to the test requirements.
The draft of the NEMI acceptance test requirements document is available at http://www.nemi.org/projects/ese/tin_whisker_activities.html.
Copyright 2004, UP Media Group. All rights reserved.
Assembly Technology Expo will take place Sept. 28-30 in Rosemont, IL, and will feature a keynote address by actor John Ratzenberger, producer and host of the Travel Channel's John Ratzenberger's Made in America series that honors the creative and entrepreneurial spirit of American manufacturing. Ratzenberger will share insights that he has gained visiting American factories and working alongside the men and women who produce many of America's best-loved products, including Harley Davidson motorcycles, Chevy Corvettes, John Deere tractors, Craftsmen tools, Zippo lighters and Slinky toys.
"We can't imagine a more fitting way to mark ATExpo's 25th year than a tribute to the greatness and inventive spirit of American manufacturers," said Kelvin Marsden-Kish, vice president of the assembly family of events, produced by Reed Exhibitions. "Mr. Ratzenberger is clearly passionate about great American products and respects the skill and dedication of the men and women who create them. He has become a highly effective advocate of American ingenuity at work and of manufacturers who invest in the effort to maintain a competitive edge here in the U.S."
For Ratzenberger, manufacturing is much more than an abstract concept. It's a way of life and a source of pride that ties communities and generations together. The son of blue collar working parents in one of the northeast's leading industrial cities, Ratzenberger grew up with the idea that Americans were hardworking inventors and problem solvers. Before turning to an acting career, he worked as a carpenter and takes pride in pointing out the houses that he helped build to his children. Despite his celebrity status, Ratzenberger still regards himself as a garage tinkerer. He holds five patents for a packaging process that he invented.
"I've always had a high regard for people who put their hands to something useful," Ratzenberger said. "A tool and die maker is an artist on par with those who display their works in expensive art galleries. A painter can always paint over a mistake. But when you work with tolerances of 1/1000th of an inch on a spinning lathe, you can't afford to be careless."
Ratzenberger is perhaps best known for his portrayal of the know-it-all, nebbishy mailman Clifford C. 'Cliff' Clavin, Jr. in the sitcom Cheers. His movie acting credits include roles in Superman and Superman II; Star Wars V-The Empire Strikes Back; Ghandi; and all five of Pixar's animated feature films, providing the voices for Hamm in Toy Story and Toy Story 2, PT Flea in A Bug's Life, the Abominable Snowman in Monsters, Inc. and a school of moonfish in Finding Nemo.
Copyright 2004, UP Media Group. All rights reserved.
Led by its members, IPC (Northbrook, IL) pushed for a fair, open and rules-based international trading system at its recent Capitol Hill Day, an industry lobbying event.
In more than 50 appointments with lawmakers, senators and their staff, IPC's Government Relations Committee and more than 40 industry leaders lobbied Congress to enforce the U.S.' international trade agreements and more aggressively officiate U.S. trading partners' obligations under the World Trade Organization and other international trade agreements. In particular, Capitol Hill Day attendees asked Congress to keep the pressure on U.S. trading partners that manipulate their currency in order to gain a competitive and trade advantage over their U.S. counterparts.
During his keynote address, Rep. Donald Manzullo, chairman of the House Small Business Committee, emphasized that lower business costs, not protectionist trade policies, will revitalize the U.S. manufacturing sector.
Congressman Phil English (R-Pa.) concurred with Manzullo in his address, as he discussed his countervailing duty bill and other congressional efforts that help level the playing field with foreign competition.
"After a three-year absence, IPC's GR Committee decided to bring back this important program to assist our members in continuing the industry recovery," said IPC President Denny McGuirk. "IPC's lobbying efforts, though, extend beyond this one-day event and cover a vast array of policies that greatly impact today's U.S. electronics manufacturer. Presently, we are lobbying to reduce the corporate tax rate on U.S. manufacturing and production income by 3%, and, to maintain competitiveness, we are supporting the extension of the research and development tax credit and the bonus 50% depreciation. IPC staff is also working on several important environmental initiatives, including a reduction of Toxics Release Inventory (TRI) reporting burdens, a broader exclusion of all recycled materials and development of lead-free labeling and materials declaration."
After recent lobbying efforts at the state and local level, Gov. Arnold Schwarzenegger's recently signed the California's Workers' Compensation Reform Bill, which promises to save up to $7 billion a year for the state's employers. IPC also successfully opposed a bill in Maine that would have banned all brominated flame retardants, including TBBPA-the main flame retardant in printed circuit boards.
Copyright 2004, UP Media Group. All rights reserved.
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