Agere Systems Uncovers Method to Overcome Barriers to Global Lead-Free Chip Implementation

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Agere's new semiconductor packaging recipe aims to increase reliability and performance of chips while eliminating lead -- a hazardous material widely used in chips today. Lead-free semiconductor packaging is being required by the European Union in just over a year, but will be implemented globally in nearly every semiconductor package produced -- impacting the trillions of microchips produced worldwide every year by the $166 billion semiconductor industry*. Every company manufacturing or using chips in electronic products is working on finding the right combination of materials to allow its products to be sold throughout Europe and in other countries adopting similar legislation. Agere's research provides a solution to the potential problems caused by the change in manufacturing processes.

Agere, like most companies in the industry, has investigated the right mix of packaging materials to yield reliable lead-free products. The key to Agere's discovery is taking into account the customer's needs when evaluating the quality of the product before shipping it.

Most chip packages being shipped today use a layer of tin and lead over copper. As companies move toward lead-free packaging, many of these packages will be using a combination of just tin over copper and will be processed by electronics equipment manufacturers at temperatures significantly hotter than packages with lead in them. Agere's work has demonstrated that tin over copper packaging will pass today's industry standard tests developed for products containing lead. However, when using the products like the customer uses them, Agere has observed that commercially available tin over copper packaging form "whiskers" that can create electrical shorts or break off and cause other system failures.

Three tests have been proposed by the JEDEC Solid State Technology Association with guidance from the National Electronics Manufacturing Initiative (NEMI) to more effectively screen for the susceptibility to tin whiskers. Of the three tests, two display no discernable difference between matte-tin on copper and nickel undercoated matte-tin on copper. Agere has demonstrated that a layer of nickel between the copper and the layer of tin provides dramatic improvements in the third test using the real-world customer environment.

The "Tin Whisker" Problem

In its own work to implement lead-free packages, Agere evaluated semiconductor packages from multiple sources using various tin plating processes. Agere observed "tin whiskers" would grow on semiconductor packages after the packages had gone through a lead-free assembly process onto circuit boards where just tin was used for the metal plating instead of lead. Tin whisker growth is a problem because these whiskers can grow to a length that creates electrical shorts that would lead to the failure of electrical systems. To solve the problem, Agere added a layer of nickel between the layers of tin and copper and discovered that tin whisker growth was mitigated in that scenario. Agere disclosed its findings in a white paper published on the company's website (http://www.agere.com/).

"We are unveiling these findings in hopes that the electronics industry will adopt our approach to avoid the problems Agere observed in currently accepted copper and tin packages," said Melissa Grupen-Shemansky, Ph.D., Agere's director of packaging and interconnect technology. "We evaluated multiple options being used by other semiconductor companies in a scientifically valid study over a prolonged timeframe and found that Agere's tin-nickel-copper combination resolved the tin whisker problem seen after high-temperature, high-humidity storage."

Early results from an independent study conducted by the NEMI tin whisker test group corroborate the Agere findings on whiskers found on commercially available tin over copper packages. NEMI will publish their findings in 2005.

Inside an electronic system, microchips are typically protected within a plastic or ceramic housing, commonly referred to as a package. Chip packaging performs three major functions: protecting the chip from the external environment, enabling electrical connectivity and dissipating heat. Until now, many packages have been coated most often on the metal "fingers" that connect the chip to the circuit board with a mixture of tin and lead to enable efficient and reliable solder attachment to system circuit boards. The addition of lead to the metal-plated alloy has proven to effectively stop the growth of tin extrusions -- or "whiskers." Tin whisker growth is a stress-driven mechanism that may yield whiskers of sufficient length to disrupt electrical connections causing failure of the microchip.

Many companies moving to lead-free packages use a combination of just tin and copper in their packaging. However, the tin-copper combination shows whisker formation in lifetime reliability studies when subjected to the assembly conditions seen by electronics equipment providers. In Agere's evaluation of samples from multiple packaging vendors, these solutions would not be acceptable to the electronics industry in applications where long-term reliability must be assured. The company's research has proven that a tin, nickel and copper combination is a reliable alternative.

While Agere effectively provides the industry's currently accepted tin and copper combination for some packages requested by customers, the company has taken additional steps to ensure a higher level of reliability for customers that require it.

"The impact of tin whisker growth in lead-free semiconductor packaging would be disturbing to the electronics industry because businesses and consumers risk increased equipment failure as a result of electrical shorts caused by these tin whiskers," said John Pittman, vice president of assembly and test operations for Agere. "The nickel solution can help facilitate the widespread adoption of lead-free packaging. The good news is that nickel is common in packaging processes today, so a "whisker-free" tin-nickel-copper solution can be easily implemented by the industry."

Agere is shipping lead-free semiconductor products to customers using the new packaging process developed by the company. It will transition the majority of its product portfolio to lead-free packaging by summer 2005.

Agere Systems is a global leader in semiconductors for storage, wireless data, and public and enterprise networks. The company's chips and software power a broad range of computing and communications applications, from cell phones, PCs, PDAs, hard disk drives and gaming devices to the world's most sophisticated wireless and wireline networks. Agere's customers include the top manufacturers of consumer electronics, communications and computing equipment. Agere's products connect people to information and entertainment at home, at work and on the road -- making personal broadband a reality. More information on Agere is available at its website http://www.agere.com/.

  * Semiconductor Industry Association 2003 industry revenue report,
    February 2004

This release contains forward-looking statements based on information currently available to Agere. Agere's actual results could differ materially from the results stated or implied by such forward-looking statements due to a number of risks and uncertainties. These risks and uncertainties include, but are not limited to, our ability to keep pace with technological change, our dependence on new product development, price and product competition, availability of manufacturing capacity, customer demand for our products and services, general industry and market conditions, and our reliance on major customers and suppliers. For a further discussion of these and other risks and uncertainties, see our annual report on Form 10-K for the fiscal year ended September 30, 2003, and our quarterly report on Form 10-Q for the period ended June 30, 2004. Agere disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

CONTACT: Contact: Steven Goldsmith, Allentown, Pa., USA,
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Balbo, Ascot, UK, +44-1344-865-844, or cell, +44-7789-743-069, or
lbalbo@agere.com

Web site: http://www.agere.com/