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SDK Develops Waterborne Patterning Photoresist Ink

June 3, 2002

Showa Denko K.K. (SDK) has developed an environment-friendly waterborne patterning photoresist ink (trade name: SHORAX NP-30/WB) for the production of printed circuit boards. This product, having many advantages over traditional photoresist ink based on organic solvents, is a result of joint development with Nippon Polytech Corporation, a venture-capital company specializing in the photoresist ink business and is now a subsidiary of SDK.

Printed wiring with photoimageable patterning photoresist ink provides lower cost and higher pattern accuracy compared with photoimageable dry film. Specifically, the substrate coating cost is ¥100-150/m2 for patterning photoresist ink compared with ¥200-300/m2 for dry film. Furthermore, the resolution improves to 25µm of line/space width when patterning photoresist ink is used whereas the comparable figure is 50µm for printed wiring with dry film.

Despite such advantages, the use of patterning photoresist ink has been limited because all such inks use flammable organic solvents classified as hazardous material under the Fire Service Law.

The newly developed SHORAX NP-30/WB, having extremely low flammability and organic solvent smell, does not come under the category of hazardous material under the law. At the same time, the new product ensures good drying and development as well as high circuit density like conventional organic solvent-based inks.

SHORAX NP-30/WB is to be used in dip coating process. SDK and Nippon Polytech will also provide, in the near future, new grades to be used in screen printing and roll coating processes.

Waterborne ink was considered to result in lower sensitivity and drying speed, as well as in deterioration in smoothness of coating. To solve these problems, SDK's photo initiator technology has been combined with Nippon Polytech's expertise in photoresist ink. Namely, water-soluble organic solvent has been introduced to increase drying speed while dispersibility of photo initiator / crosslinking agent has been improved for higher sensitivity.

SHORAX NP-30/WB will be manufactured and sold by Nippon Polytech, and annual sales of the product will amount to ¥1 billion in three years' time. In view of the advantages of patterning photoresist ink over dry film and growing demand for still higher circuit density, the size of market in Japan for waterborne photoresist ink is expected to reach ¥3 billion in five years.

In 1998, the dry film market in Japan was approx. ¥16 billion in size. The organic-solvent-based patterning photoresist ink market was about 10% of that scale.

SHORAX NP-30/WB will be presented at the Japan Print Circuit Association Show scheduled for inauguration on June 5 at Tokyo Big Site.

In the medium-term consolidated business plan, SDK is committed to the electronics market, allocating much of its resources to the development of value-added specialty chemicals.

For further information, contact:
Specialty Chemicals Division (Phone: 044-329-0721) (for customers)

Outline of Nippon Polytech Corp

Address 358-2, Nibukata-machi, Hachioji City, Tokyo
President Atsushi Kabe
Established In July 1989
Capital ¥10 million
Ownership Showa Denko K.K. 60%; Atsushi Kabe 40%
Business Development, production and sale of photoresist for the manufacture of printed circuit boards
Annual sales ¥500 million (for fiscal 2001 ended December 31)
Telephone number 042-652-0216