Matsushita Electric Industrial Co., Ltd.

Toshio Sugawa

Hideki Higashitani

Tadashi Nakamura

Masahide Tsukamoto

Daizou Andou

Kaoru Inoue

Ryoichi Takayama

Takashi Hirao

Takeo Yasuho

Masaaki Hayama

Keizaburo Kuramasu

Yoshihisa Takase

Satoshi Murakawa

Shigetoshi Takayanagi

Takeshi Onuma

Takumi Misaki

A circuit board is manufactured by filling a via-hole formed in an insulating substrate with conductive material, disposing conductive layers on both sides of the insulating substrate, and forming alloy of component material of the conductive material with component material of the conductive layers. In the circuit board, therefore, the conductive material filled in the via-hole formed in the insulating substrate is securely connected electrically as well as mechanically to the conductive layers on both sides of the insulating substrate with high reliability.

Circuit board and method of manufacturing the same

A circuit board includes an insulating substrate, a first conductive layer on the insulating substrate, a second conductive layer on the first conductive layer, and a third conductive layer covering the first conductive layer and the second conductive layer. The first conductive layer has a surface provided on the surface of the insulating substrate, and a surface having a width smaller than a width of the above surface. In this circuit board, the conductive layers have small impedances even if a high-frequency signal flows in the conductive layers.

A circuit board is provided in which peeling strength is prevented from decreasing and a connection resistance to a conductive material is prevented from increasing, though the contact area decreases when the circuit board has a copper foil. This circuit board has a metal film for covering a through hole on at least one surface of an insulating substrate having the through hole filled with the conductive material. An uneven layer with a thickness of 5 &#x3bc;m or more is formed on a surface of the metal film, and a metal layer is formed on the opposite surface to the uneven layer.

Circuit board and its manufacturing method

Through holes formed in an electrical insulating substrate having adhesive layers on its both surfaces are filled with a conductor. Then, supporting bases having wiring layers with a predetermined pattern are laminated on both the surfaces of the electrical insulating substrate, which are then heated and pressurized. After that, the supporting bases are removed, thus obtaining a circuit board in which the wiring layers have been embedded in the adhesive layers. The conductor within the through holes are compressed sufficiently, thus forming minute via holes with high reliability.

A SAW device comprising an inter-digital electrode capable of withstanding application of excessive electric power, while preventing an increase of insertion loss. The SAW device has an inter-digital electrode formed by alternating layers of aluminum films and conductive films, where the conductive films have an elastic constant greater than that of the aluminum films.

Saw device and its manufacturing method

A junction-type FET comprising a semiconductor substrate 21 of a first conductivity type, and island region 22 of a second conductivity type which comprises a channel region and is selectively formed in the semiconductor substrate 21, and a buried isolating region 27 which is selected from the group consisting of an intrinsic layer, a low impurity concentration layer of the second conductivity type and a layer of first conductivity type, the buried isolating layer being formed by ion implantation of impurities of the first conductivity type in the island region 22 while keeping the impurity concentration at the surface thereof relatively high, and the buried isolating layer substantially isolating the channel region from the surface.

Growing community of inventors

Katano, Japan

Toshio Sugawa