Members' Profiles

KOA Corporation
1. Endeavors in Ceramic Packages
KOA Corporation has specialized in the manufacturingof electrical resistors for more than sixty years since its
foundation and is a world leader in the types andproduction of electrical resistors through its worldwide
sales network. Utilizing our base technologies in thinfilms, thick films, electroplating, and ceramics andinnovative production activities, our objective is tocontribute to production that respects humanity, reduces
environmental impact, and enriches our lives.
Since 2001 we have been developing andmanufacturing LTCC (Low Temperature Co-firedCeramics) multilayer substrates as one of our newest
endeavors, incorporating base technologies developed
through the production of electrical resistors and various
other electronic parts. The LTCC multilayer substrate isformed of a material that supports electronic devices,which continue to be made faster, smaller, lighter, andthinner, with more advanced functions. Moreover, KOA
LTCC substrates not only have the excellent properties
characteristic of ceramic substrates, but also have thecapacity to respond flexibly to special shapes. There isalso expectation that, in addition to electronic devices,
these substrates will be developed as packages for use in
MEMS technology.

General Manager, LTCC Business Center

Takuo Hayasi
3. Features of KOAs LTCC
Through KOA’s own shrinkage control technology andmultilayer technology, LTCC substrates can be produced_ 0.05% the design specifications.
with a high accuracy of +These technologies also make it possible to form thickfilms, thin films, and fine patterns using inkjet technology
and to form resistive elements in surface layers and innerlayers. By adding a green sheet layer with a cutout
portion, cavities, hollow structures, and other complex
shapes can be produced accurately. While LTCCs arewidely used as substrates for small modules, the excellent
properties possessed by LTCC materials suggest thatapplications for these substrates could be expanded
through processes using the latest technologies.

2. LTCC Multilayer Substrates
LTCC is a ceramics technology in which glass material
is added to alumina, enabling the alumina to be fired at a“low temperature” of 900 ; or less and can be used for
simultaneously firing Ag as a conductor. In addition totheir excellent heat resistance and humidity resistance,
ceramic substrates also have excellent frequency
characteristics (low loss) in high frequency circuits.
Employing KOA’s multilayering technique facilitates theformation of wiring patterns in surface layers and inner
layers, making it possible to produce three-dimensional
multilayer wiring at a high density. Since the LTCC
substrates have a thermal expansion coefficient closer tosilicon than do other organic substrates and ceramic
substrates, less stress is produced during mounting, giving
the LTCC substrates broad applications in high-frequency,
multi-chip modules and circuit boards for semiconductor
packages.

Photo 1 Cavity package

Photo 2 One example of a special shape in which(squarecolumns have been formed in a cavity)

4. Endeavors in MEMS Packages
While LTCC substrates have been primarily used inhigh frequency modules, development is currently
underway on other applications for these substrates, suchas in MEMS packages.
We are working to provide high-precision packages
that draw out maximum performance in MEMS devices
developed by our customers, such as ultrafine, high-levelsensors and functional components. By further improving
the LTCC technology for high-precision, high-density
wiring and producing packages having a higher addedvalue, KOA believes it can contribute to MEMS
development and product commercialization. It is ourhope that customers see the advantages of LTCC andincorporate these substrates in various applications.

MICRONANO No. 58
MICRONANO is published quarterly by Micromachine Center (MMC) to promote the international exchange ofinformation related to micromachines, R&D and other technical topics, and is circulated free of change. Please send
your comments about MICRONANO to the publisher :Keiichi Aoyagi, Executive Director, Micromachine Center (MMC)
MBR99 Bldg., 6F., 67 Kanda Sakumagashi, Chiyoda-ku, Tokyo 101-0026, Japan
Tel : +81-3-5835-1870, Fax : +81-3-5835-1873
Internet Home Page h t t p : / / w w w . m m c . o r . j p /Date of Issue : February 14, 2006

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