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SUMITOMO BAKELITE CO., LTD. (Headquarters:
at Shinagawa ward, Tokyo, President :Tsuneo Moriya) has developed low dielectric
materials " LεB SERIES" comprising a copper foil having resin thereon
"APL-4901" for high frequency substrates and multiplayer substrate materials for
printed circuit boards comprising thin copper clad laminate ELC-4788 and prepreg
EI-6788.
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| Social Background |
With the incoming of the "Age of High Speed Communication of Huge
Amount of Information" advanced LSIs. require lower dielectric performance
of printed circuit boards to meet the higher processing rate and increased
number of pins. High dielectric constant will often cause noises such as
cross-talks between circuit lines and the disturbance of signal wave shape
with narrower and closer distance between adjacent signal lines in consequence
of pursuing finer pitches. High dissipation factor on the other hand will
develop big signal loss to make it impossible to maintain the original
wave shape. Either of the above will cause malfunctions of LSIs. or completely
hinder the proper operation of the devices. Thus, the industry really wants
qualified materials for PCB with dielectric properties far superior to
those of conventional materials. For substrates which require such low
dielectric properties so far fluoro-plastic and special types of thermoplastic
materials have been used for printed circuit boards. However, such kinds
of low dielectric property materials meet difficulties in performing the
same conventional processing for multi-layer substrates due to restrictions
from the characteristics of such resins leaving them as rather too specific
substrate materials. While, the newly offered copper foil having resin
thereon for low dielectric property build-up material is a creative new
product such as was not available so far. As signal transfer in the GHz
frequency range is getting popularly seen not only in device packages and
module substrates but also in the main boards of the base stations and
switch boards of cellular phones, conventional general purpose epoxy materials
(ε = 4.0-4.5, tanδ = 0.02-0.03) will sometimes cause malfunctions. Thus,
we have developed the above products which meet the market needs for lower
dielectric properties as well as for the convenience of processing printed
circuit boards by using the same existing equipment and method for thermosetting
materials.
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Note: As represented in the following formula, it is preferable
for materials of printed circuit boards to have low dielectric constant and low
dielectric dissipation factor.
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Propagation velocity=K * (C/√ε)
Propagation loss= K * (Frequency/C) * √ε * tanδ
wherein ε : dielectric constant
tanδ : dielectric dissipation factor
K : constant
C : light velocity |
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| Features of recognized system
materials |
Two Japanese thermosetting material makers including
us and another company had obtained recognition of the system(B) from UL earlier
than this time and have been supplying the system materials but the systems of
both companies had limitations to transformer structures and practically could
not find wide use. The systems of insulating materials Class B recognized this
time apparently improved the free designing allowance of transformers by
increasing applicable materials and components in compliance with each
transformer manufacturer's requests as wide as possible.
The materials for
transformer bobbins are molding compounds "SUMIKON PM" and "SUMIKON AM " of
Sumitomo Bakelite which have superior long term electrical reliability and
mechanical strength. They are available in a wide line-up of grades enough to
meet the rising solder temperature along with the requirement for lead free
solder. We aim to expand sales of thermosetting molding materials in the
transformer market by supplying this system.
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* Temperature rating: Class B (130°C)
* Compatibility to various kinds of insulation: Compatible to insulation by
bobbins, insulating tapes, and 3-ply insulating wires.
* Insulating tapes of various types can be used in a wide range of selection.
* Components such as insulating tubes and covers can be chosen widely.
* Bobbin materials (diallylphthalate) with CTI 600V can be used.
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| We forecast increasing future demand for higher
temperature ratings of transformers especially in applications of industrial and
communication apparatus and devices and we are simultaneously working for
acquiring recognition of Class F (155°C) systems of insulating
materials . |
| Description of the developed
products |
| 1. APL-4901 (copper foil with resin)
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| 1. |
The dielectric constant of the product(ε) is 2.8 and
the dissipation factor (tanδ) is 0.0025 at 1 GHz. Such much lower dielectric
figures than those of conventional epoxy materials are stably exhibited in GHz
ranges. |
| 2. |
As for the resin, it is a heat resistant
thermosetting resin having a glass transition temperature higher than
3000C. |
| 3. |
The water absorption ratio is 0.2w%, which is less
than 1/5 of conventional epoxy materials. |
| 4. |
Halogen-free, antimony-free, and phosphorus-free
:namely, an environment-friendly material. |
| 5. |
In order to form a uniform insulating layer thickness
the resin flow during press lamination can be controlled.
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| 2. ELC-4788 ( Thin copper-clad laminates, for cores
of multi-layer laminates) and EI-6788 (Prepreg) |
| 1. |
The dielectric constant of the product(ε) at 1 GHz
can be reduced from 3.5 to 3.2 by using low dielectric glass. And the
dissipation factor (tanδ)is 0.0060 at 1 GHz., which is about 1/4 of
conventional epoxy materials. |
| 2. |
As for the resin, it is a heat resistant
thermosetting resin having a glass transition temperature higher than
300°C. |
| 3. |
The water absorption ratio is held about half of
conventional epoxy materials. |
| 4. |
Laminators can use conventional vacuum press where
the same processing ability as FR-4 is
exhibited. |
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| Distinguished features of the
technologies |
| 1. APL-4901 (Copper foil with resin) |
| 1. |
We started the marketing of the low dielectric
property copper foil with resin which was developed for the first time in the
world. The low dielectric constant of the product(ε) in the level of 2.8 and
the extremely low dissipation factor (tanδ), 0.0025 both measured at 1 GHz
enable to use it as a build-up material for substrates of device packages,
modules for communication apparatus as well as mother boards of base stations,
server substrates, etc. |
| 2. |
Dependence of the dielectric properties on frequency
is so small as to facilitate the application in extensive ranges of
frequencies. |
| 3. |
Extremely high TG coupled with extremely low water
absorption ratio make itself remarkably invulnerable to environmental changes in
the conditions during usage such as temperature and humidity to protect and
maintain the dielectric properties. |
| 4. |
Uniform thickness of the insulating layer can be
secured almost regardless of the dependence of inner layer substrates on
patterns by regulating the resin flow during press lamination to facilitate
impedance control. |
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| 2. ELC-4788 ( Thin copper-clad laminates, for cores
of multi-layer laminates) and EI-6788 (Prepreg) |
| 1. |
The dielectric constant of the regular type (ε)=3.5
and that of low dielectric glass type= 3.2 both at 1 GHz are really unparalleled
in this kind of highly multi-layered laminates comprising glass
cloth. |
| 2. |
Extremely high TG coupled with extremely low water
absorption ratio make itself remarkably invulnerable to environmental changes in
the conditions during usage such as temperature and humidity to protect and
maintain the dielectric properties. |
| 3. |
Laminators can use conventional vacuum press where
the same processing ability as FR-4 is
exhibited. |
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| Patents |
10 relevant patents pending.
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| Sales target |
| JPN yen 500,000,000 in 2002 as a total sum of the products herein described. |
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Thank you. |
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