Fujitsu Laboratories, Ltd., Fujitsu Quantum Device Ltd. and Fujitsu
Limited have jointly developed prototype flip-chip(*1) MMICs(*2) for use in transmitters and receivers for 76 GHz automotive radar systems. The prototype devices are at present the world's highest frequency
flip-chip MMICs capable of being mass-produced.
A paper introducing the technology behind this development will be
presented at ISSCC2000 (the 2000 IEEE International Solid-State
Circuits Conference), which will take place February 7-9 in San
Francisco.
Automotive radar technology is currently used in systems supporting
safe and comfortable driving, such as collision warning and cruise
control, and it is considered to be a key technology for the
realization of ITS (Intelligent Transport Systems). In order to more
widely disseminate this radar technology, which up to now has found
only limited use, it is necessary to further reduce the size and cost
of the MMIC devices that comprise these systems. Moreover, since the
allocated frequency for automotive radar systems is 76GHz in Japan,
the USA and Europe, high performance ultra-high frequency range
devices will be essential.
However, up to now it has been difficult to achieve mass production
and improve the performance of the MMICs because gains in
miniaturization have tended to be offset by increases in parasitic
resistance and electric capacitance.
In addition, the length of the wiring between chip and package has a
strong effect on the performance of chips in this frequency range.
Conventional MMICs usually have been connected to packages with fine
metal wires called "bonding-wire," however, chip positioning was not
sufficiently precise and wiring length was not uniform enough to
enable mass-production of 76GHz circuits.
Overcoming these hurdles, Fujitsu developed a series of MMICs that
operate at 76GHz using a HEMT with 0.15um gate. At the same time, it
developed related assembly technologies to enable mass production.
With Fujitsu's flip-chip package technology, micro-metal pillars are
formed during the wafer fabrication process and used for connecting
the chips to the package substrate. This makes possible accurate
chip-positioning and enables high-performance devices to be formed
on a simple structure.
Fujitsu's prototype MMICs can be used to configure a transceiver for
FM-CW automotive radar, including amplifier, mixer, doubler, and
duplexer circuits. By taking the place of more expensive components
used heretofore, the new, mass-producable MMICs are expected to
contribute more economical automotive radar systems.
Explanation of terminology
(*1) Flip-chip
This is packaging technology whereby electrical connection is made
by lining up many pillar-like metal contacts on the surface of the
chip and turning them down to connect the chip to the substrate.
(*2) MMIC(Monolithic Microwave Integrated Circuit)
This is a high frequency analog integrated circuit on which active
devices such as transistors and diodes and passive circuits such
as transmission lines, capacitors and resistors are formed.
* All company/product names mentioned may be trademarks or registered trademarks of their respective holders and are used for identification purpose only.
About Fujitsu Limited
Fujitsu Limited (TSE: 6702) is a leading provider of comprehensive
information technology and network solutions for the global
marketplace. Comprising over 500 group companies and affiliates
worldwide -- including ICL, Amdahl and DMR Consulting Group -- the
Fujitsu Group had consolidated revenues of 5.24 trillion yen
($43.3 billion) in the fiscal year ended March 31, 1999. With world-
class hardware and software technology in computers,
telecommunications and microelectronics, and a corps of 55,000
systems and services experts around the world, Fujitsu is uniquely
positioned to harness the power of the network to help its customers
succeed. Altogether, the Fujitsu Group has 188,000 employees and
operations in over 100 countries.
Homepage: http://www.fujitsu.com/
Fujitsu Laboratories Ltd.
Founded in 1968 as a wholly owned subsidiary of Fujitsu Limited, Fujitsu
Laboratories Ltd. is one of the premier research centers in the world.
With five laboratories in Japan and one in the United States, the
organization conducts a wide range of basic and applied research in the
areas of Multimedia, Personal Systems, Networks, Peripherals, Advanced
Materials and Electronic Devices.