The Furukawa Electric Co., Ltd.

Furukawa Circuit Foil Co., Ltd.

Furukawa Circuit Foil., Ltd.

Yuuki Kikuchi

Yuuji Suzuki

Akira Matsuda

Sadao Matsumoto

Hideo Otsuka

Satoru Zama

A through-hole type laminated circuit board is given with high reliability of electrical connection using copper foil and conductive paste containing low melting point metal without generating harmful void and crack at boundary between the copper foil and conductive paste metal. The laminated circuit board is made by laminating a multiple number of resin boards with roughening treated copper foils at least on their one surface sides with roughening projection deposition of less than 150 mg/dmto make surface roughness Rz of 0.3 to 10 &#x3bc;m and height of the projection to be 0.3 to 10 &#x3bc;m. Surface roughness of the original foil is 0.1 to 5 &#x3bc;m and the amount of copper metal atoms of roughening treated layer is set at 4 times or less than the amount of diffusible conductive paste metal atoms containing low melting point metal into the roughening treated layer on the foil surface.

Laminated circuit board

A plating bath, able to form a resistance layer with a uniform thickness distribution on the roughened surface of a conductive base, including nickel ions and sulfamic acid or its salt as essential components and at least one of phosphoric acid, phosphorous acid, hypophosphorous acid, and salts of the same; a conductive base having a thin resistance layer with a stable resistance, and a resistance circuit board material using the same.

Method for preparing a circuit board material having a conductive base and a resistance layer

A conductive substrate with a resistance layer comprising a substantially flat high conductivity substrate roughening treated on its surface by a resistance component and provided with a resistance layer by the resistance component so as to enable the interface between the high conductivity substrate and resistance component layer to be substantially flattened, enable acquisition of a thin film resistance layer with a stable resistance after dissolving away the high conductivity substrate, and able to maintain the peel strength with the insulating support, and a resistance board using the same.

Conductive substrate with resistance layer, resistance board, and resistance circuit board

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Nikkou, Japan

Yuuki Kikuchi