Hitachi Chemical Co., Ltd. has developed a new base material for multi-layer printed wiring boards. The new base material, named "Cute®," is flexible and extremely thin (50 microns or thinner), and will be marketed in earnest from FY 2005. Cute® is manufactured by applying the company's epoxy-based, low elastic modulus thermosetting resin to coat and impregnate 20-micron or thinner glass cloth and then overlaying it with copper foil. The new product should play an effective role in efforts to further miniaturize and slim down portable digital products such as digital camcorders, camera phones, etc.
The newly developed "Cute®" utilizes extremely thin (20 microns or thinner) glass cloth as the core material, although it had not been actively employed for reliability reasons. Hitachi Chemical, however, has succeeded in manufacturing an ultrathin and multi-layer PWB base material that not only provides high strength and dimensional stability, but that can also be freely deformed as needed. Hitachi Chemical accomplished this by applying an epoxy resin of its own development, which has excellent properties in such as flexibility, heat resistance, adhesiveness, low coefficient of thermal expansion, etc., to coat and impregnate the core material.
A Cute®-based four-layer PWB can be manufactured with a thickness less than a half that of the prevailing four-layer PWBs. It can also eliminate the connectors that were otherwise necessary for connection between the rigid and flexible boards as in the case of flexible PWBs. These advantages, plus the fact that they are foldable, should make the CuteR-based PWBs suitable for use in even smaller spaces and help provide more freedom and new possibilities in designing portable digital products.