Marion Kenefick
(408) 354-1181
Fujitsu's new plastic BGAs are available in JEDEC-standard I/O configurations ranging from 256 to 576 pins. Custom Single Chip Packages (SCPs), multi-chip modules, and multi-chip packages also are available. Fujitsu's PBGAs use a small ball pitch with multilayer construction to provide high mounting densities, and copper heat spreaders that enable thermal performance that is better than any other packaging option. Another key benefit of plastic BGAs is electrical performance, which is improved because power demands are significantly lower than with other packages.
The reduced spacing characteristics of Fujitsu's BGAs are very important for the latest generations of notebook computers and other products that will supply significant performance improvements, according to Vincent Sollitto, FMI business unit organization vice president and general manager. "System clock speeds in new computer and consumer products are increasing rapidly, driving the need for innovative surface mounting packages, such as ball grid arrays," he said.
"Our plastic versions are easy to assemble, provide excellent thermal and electrical performance, and permit manufacturers to raise their yields. We have established close working relationships with our customers worldwide in order to optimize our packaging options," said Ajay Mody, director of marketing, interconnect technology. Mody noted that low-cost, low-end BGA versions are being adopted in consumer applications, while the higher density, higher performance versions are attractive for advanced computing designs, including notebooks and subnotebooks, where space and performance are critical. BGA packaging also provides advantages for higher pin count devices used in high-end workstation and telecommunications products.
Many leading customers and industry analysts foresee significant migration to BGA
packaging. Dataquest, Inc., for example, has estimated that BGA is now the favored option for ICs with
more than 200 pins, and will achieve parity with plastic grid arrays by 1997.
No Fragile Leads, Reduced Ground Bounce
There area several advantages to ball grid array technology. Plastic BGAs use solder balls instead of leads as the connection to the printed wiring board or next-level interconnect. Because BGAs do not have the fragile leads that characterize quad flat packs, they can be assembled much more easily on the printed circuit board, using surface mount assembly equipment and infrared reflow processes.
The small footprint and short electrical connections from the conductor layers to the solder balls reduce the potential for ground bounce by lowering the trace inductance between the solder balls and conductor layers. Short traces also enable smaller signal delays, yielding significantly improved electrical performance compared with plastic quad flat packs and other common packages. All vias are run inside the footprint, next to the pads. If thermal dissipation becomes a critical problem for a particular package, a copper heat spreader placed on the PBGA draws heat upward, guaranteeing high thermal performance.
Plastic BGAs in production volumes come in four JEDEC-standard I/O configurations, ranging from 256 to 576 I/Os. Ball pitch is 1.27 mm. Dimensions range from 27 mm (length) x 27 mm (width) x 3.5 mm (height) to 40 mm x 40 mm x 3.5 mm. Various customized I/O versions are available, depending on the application. BGA packages with more than 1,000 pins will be available by the first calendar quarter of 1996. Pricing for products in PBGAs depends on the application and on other design factors.
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FOR FURTHER INFORMATION:
Betsy Taub
Fujitsu Microelectronics, Inc.
(408) 922-9440
Dick Davies
Independent Public Relations Assoc.
(415) 777-4161