Ibiden Company Limited

Tetsuo Amano

Toshio Nishiwaki

Toru Nakai

Yoshinori Takasaki

A printed wiring board includes a core insulation layer including a resin and having a via conductor through the core insulation layer, a first conductive layer formed on the core layer and including a copper foil and a plated film, an interlayer insulation layer formed on the first layer and including a resin, the interlayer layer having a via conductor through the interlayer layer, and a second conductive layer formed on the interlayer layer and including a copper foil and a plated film. The first layer includes a conductive circuit, the core and interlayer layers have dielectric constants of 4.0 or lower for signal transmission at frequency of 1 GHz and thermal expansion coefficient of 85 ppm/&#xb0; C. or lower at or below Tg, and the foil of the first layer has thickness greater than thickness of the foil of the second layer.

Printed wiring board

A printed wiring board includes a core insulation layer having via conductors through the core layer, a first structure including an interlayer insulation layer on first surface of the core layer and having via conductors through the interlayer layer in the first structure, and a second structure including an interlayer insulation layer on second surface of the core layer and having via conductors through the interlayer layer in the second structure. The interlayer layers have dielectric constants set to be 4.0 or lower for signal transmission at frequency of 1 GHz, the core layer has thermal expansion coefficient at or below Tg set lower than thermal expansion coefficients of the interlayer layers at or below Tg, the coefficient of the core layer at or below Tg is set to be 75 ppm/&#xb0; C. or lower, and the conductors in the interlayer layers are stacked on the conductors in the core layer.

A method for manufacturing a printed wiring board including forming an insulative resin layer containing a resin and an inorganic filler, forming a conductor layer including a conductive material and having a conductor on the insulative resin layer, irradiating a laser beam upon the conductor of the conductor layer such that the conductor is sectioned or a width of the conductor is narrowed, and forming a conductive pattern on the insulative resin layer. The inorganic filler is in an amount of 30 wt. % or more of the insulative resin layer.

Method for manufacturing printed wiring board

A wiring board includes an insulation layer containing a resin and a silica-type filler and having a roughened surface, and a conductive layer formed on the roughened surface of the insulation layer and having a first conductive portion and a second conductive portion positioned adjacent to the first conductive portion. The roughened surface of the insulation layer has a roughness under the first conductive portion, a roughness under the second conductive portion, and a roughness between the first conductive portion and the second conductive portion, and the roughness between the first conductive portion and the second conductive portion is set less than at least one of the roughness under the first conductive portion and the roughness under the second conductive portion.

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Ogaki, Japan

Tetsuo Amano