Ball Semiconductor, Inc. Will Co-Develop Sensors with Japan's Yamatake Corp.

Ball Semiconductor Inc. is working to incorporate RF transmission functions in its spherical semiconductor technology. The company also has signed a two-year contract with Yamatake Corp. (Tokyo) to co-develop sensors, particularly accelerometers, which are likely to be one of the first applications for spherical semiconductors. Yamatake, a major supplier of measurement and control systems, may have commercial products stemming from the R&D collaboration ready by spring.

Ball is already producing samples of round semiconductors, 1 millimeter across, with up to 6,000 gates etched at 1-micron line widths, according to Ram Ramamurthi, vice president of R&D. Part of the manufacturing process now takes place as the device moves through sealed tubes, and Ramamurthi said the long-term vision includes a fully automated facility where raw silicon is dropped into a long tube and emerges at the other end as a spherical chip.

Complementary strengths
"Ball Semiconductor is a fast-moving venture company with new technology, and Yamatake is a long-established company with a lot of know-how," said Miwako Waga, an analyst at the Asian Technology Information Program, who sees the companies' strengths as complementary. "Yamatake already has technologies such as MEMS and flux sensors, but the company must aim at new products that cannot be made with conventional devices."

Ramamurthi said accelerometer sensors will prove to be an ideal application for the round devices because they can sense motion along a three-dimensional axis. Adding RF transmission features makes the product even more effective, since it can then transmit the motion information to other components within a system. "This is much better than using three different chips to measure motion in three different directions," Ramamurthi said. "Incorporating RF technology is the next step for us."

Current plans call for a sensor ball chip to be clustered alongside an RF ball. The two orbs can be placed together within a system in nearly any layout. Ramamurthi said it is still not certain exactly what kind of packaging will be used with the spherical devices; they could be encased together in an epoxy resin, or the silicon balls could each be dipped in some type of thin, protective coating and placed alongside each other. The initial plans call for putting multiple round chips into a ball-grid array package, which he termed a "ball bomb."

Ramamurthi said the spherical designs are ideal for creating analog products because the shape lends itself especially well to producing inductors. "The complexity of the device is about the same for us as it is for a flat semiconductor, but the shape gives us one significant advantage in putting the inductor on the ball," he said. The company has some 60 employees now, and that could swell by r dozen within the next year. Ramamurthi said that Ball expects its technology to generate revenue next year, but he is not certain whether those sales will also lead to a profit.

Beyond sensors, Ball is exploring the microelectromechanical systems market for later products. "We are not trying to replace existing wafer-based chips," said Ramamurthi. "We are focusing on niche markets that we can serve well with our technology."

In Tokyo, Shigeo Miyagawa, manager of the control product division of Yamatake, said that one possible outcome of the deal with Ball is "a combination of the temperature sensor function and radio-frequency identification [RFID] function, which senses a temperature and transmits the data for measurement. But communicating the information over a relatively long distance is a challenge."

A year ago, Ball allied with Hitachi Maxell Ltd. to develop an IC tag by next March.

Hitachi Maxell recently announced an RFID product using conventional semiconductor technology and Hitachi Maxell's proprietary coil plating. "If a ball semiconductor is used in such RFID tags, the performance will be improved. We are going to use ball ICs," a Hitachi Maxell spokesman said.

Ball also is collaborating with Tokimec Inc. (Tokyo), a major maker of marine and airplane instruments, and the University of Tokyo for accelerometer sensor development. The three are jointly designing a product that Ball will fabricate.