Yamaichi Electronics Co., Ltd.

Hidehisa Yamazaki

Akira Yonezawa

Etsuji Suzuki

Hiroshi Odaira

An interlayer connection structure in a circuit board characterized in that a local part of a conductive circuit layer disposed at one surface side of an insulative sheet is bent inwardly of the insulative sheet so that an apex of a projectingly bent portion is formed, and the apex of the projectingly bent portion is abutted with another conductive circuit layer disposed at the other surface side of the insulative sheet so that an interlayer connection is established therebetween.

Method of forming an interlayer connection structure

An IC package is provided that has a flexible wiring sheet, including an upper portion, a lower portion and a side portion which is wound around a base member over an upper surface, side surfaces and a lower surface of the base member. An IC is loaded on an upper surface of the upper flexible wiring sheet covering the upper surface of the base member. The IC is connected to an electrode provided on an upper lead pattern portion laid along the upper surface of the flexible wiring sheet. The lead pattern is extended from the upper flexible wiring sheet to the lower flexible wiring sheet via the side surfaces of the flexible wiring sheet covering side surfaces of the base member. An electrode to be connected with an object is arranged on the lower lead pattern portion which is formed on the lower flexible wiring sheet, and overall the IC or an IC connection portion is sealed on the upper surface of the upper flexible wiring sheet.

IC package having a single wiring sheet with a lead pattern disposed

A circuit board includes a wiring board which includes an insulative board having a wiring pattern on one surface thereof, a connection hole being formed in the insulative board such that the connection hole reaches the wiring pattern, a conductive bump, which is formed by growing a plating on the wiring pattern, being embedded in the connection hole, and the conductive bump serves as a connection to a wiring pattern which is intimately attached to the other surface of the insulative board.

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Okayama-ken, Japan

Hidehisa Yamazaki