Mitsubishi Denki Kabushiki Kaisha

Satoshi Yanaura

Hirofumi Fujioka

Seiji Oka

Takeshi Muraki

Yasuo Kawashima

Hiroyuki Sato

Naoki Kato

Fumiaki Baba

Seiki Hiramatsu

Toshiyuki Toyoshima

Masuo Koga

Takamitsu Fujimoto

Kousuke Haraga

Toshiro Tsukahara

Yasuo Furuhashi

Takeji Fujiwara

Atsuko Noda

Method of producing a multi-layered wiring board comprising the steps of subjecting the photosensitive resin to exposure- and development-treatment to form the holes having a predetermined size and shape; depositing and forming the curable resin to the insulating layer having the holes formed therein in such a manner as to bury the holes, and conducting heat-treatment to form the cured thin film of the curable resin on the surface of the insulating layer; and so removing the curable resin as to leave the cured thin film to obtain the via-holes having the reduced opening size by the cured thin film.

Method of producing a multi-layered wiring board

A silicone resin for sealing a semiconductor chip. A cured silicone resin, which is obtained by curing the silicone resin at a given temperature, has a percent elongation, after fracture, measured at a room temperature, not less than 4% of a penetration number at room temperature. A semiconductor device sealed with the silicone resin, when subjected to a heat cycle or a vibration test, provides resistance to cracking, forming of voids, and interfacial peeling-off. The cured silicone resin may have a penetration number not less than 10 and not more than 80 and a loss elasticity not less than 17% of the storage elasticity. A resin member made of the cured silicone resin and sealing a semiconductor chip may include a filler, such as silica or alumina, having a coefficient of linear thermal expansion lower than that of the cured silicone resin.

Semiconductor device

In a method of manufacturing multi-layer printed wiring board, an uncured resin sheet is laminated on both surfaces of a printed wiring board having one or more layers, an organic cover film having a release property is laminated on the surfaces of the uncured resin sheets on upper and lower sides of the printed wiring board, a position of the printed wiring board is irradiated with a laser beam from the surface of the organic cover film to form a non-through hole that reaches a metal land for electrically conducting the layers of the inner printed wiring board, the non-through hole is filled with a thermosetting electrically conducting paste which is then half-cured, and the organic cover film is peeled off.

Method of manufacturing multi-layer printed wiring board

A method of manufacturing highly reliable and highly dense printed wiring board which is not warped even by the application of pressure and heat in manufacturing the multi-layer printed wiring board. The highly precise and highly dense multi-layer printed wiring board is realized by using an uncured resin sheet reinforced with fiber as an interlayer insulating layer, forming non-through holes in the uncured resin sheet using a laser beam, filling the non-through holes with a conductive paste, half-curing the conductive paste to form a wiring material, and sticking the wiring material onto the wiring substrate by application of pressure and heat, without causing a deviation in position even in applying pressure and heat.

The improved moistureproof structure for a module circuit is characterized in that a porous film conditioned to have an apparent relative dielectric constant of no more than 2.0 is coated over a stripline a high-frequency circuit, or a high-frequency device formed on a substrate, which porous film may in turn be provided with a resin coating material. The structure insures that the module circuit is moistureproof, thereby protecting it against corrosion to improve its operational reliability without affecting its electrical characteristics.

Moistureproof structure for module circuits

A head drive for a rotary drum device comprising a plurality of yokes made of magnetic material and magnets housed in the yokes for forming a plurality of magnetic fluxes. A bobbin, comprising a first material surrounds the magnets and has a coil formed on the bobbin. The coil is covered with a second material. At least one circular, non-magnetic leaf spring having an inner periphery and an outer periphery and supported at the outer periphery or the inner periphery by at least one of the yokes and the magnetic means supports the coil. Fixing members, comprising a third material are positioned at the inner periphery of the leaf spring. This third material is positively dissolved and welded to at least one of the first material and the second material with a bonding solvent whereby the leaf spring supports the coil. A prolongation at a portion of the outer periphery of the leaf spring can support a magnetic head.

Growing community of inventors

Tokyo, Japan

Satoshi Yanaura