Patent ID: 8969732
Filing Date: 2015-03-03
Classification: H05K

Abstract:
1. A printed wiring board, comprising: a core insulation layer having a plurality of via conductors comprising a plating material filling a plurality of holes formed through the core insulation layer; a first laminated structure comprising an interlayer insulation layer formed on a first surface of the core insulation layer and having a plurality of via conductors comprising a plating material filling a plurality of holes formed through the interlayer insulation layer in the first laminated structure; and a second laminated structure comprising an interlayer insulation layer formed on a second surface of the core insulation layer on an opposite side of the first surface of the core insulation layer and having a plurality of via conductors comprising a plating material filling a plurality of holes formed through the interlayer insulation layer in the second laminated structure, wherein the interlayer insulation layers in the first and second laminated structures have dielectric constants which are set to be 4.0 or lower for a signal transmission at a frequency of 1 GHz, the core insulation layer comprises a resin material and has a thermal expansion coefficient at or below Tg which is set lower than a thermal expansion coefficient of the interlayer insulation layers at or below Tg, the thermal expansion coefficient of the core insulation layer at or below Tg is set to be 75 ppm/° C. or lower, the via conductors in the interlayer insulation layer of the first laminated structure are stacked on the via conductors in the core insulation layer, respectively, and the via conductors in the interlayer insulation layer of the second laminated structure are stacked on the via conductors in the core insulation layer, respectively.