Patent ID: 7956291

Claim:
A multi-layer printed wiring board comprising: a core substrate having a plurality of through holes therein, the through holes in the core substrate being disposed so that a ground through hole and a power through hole adjoin each other, wherein a distance between the ground through hole and the power through hole is in a range of 60 to 550 μm; an interlayer insulating layer formed on the core substrate; a conductive layer formed on the interlayer insulating layer; and a plurality of via holes provided in the insulating layer and configured to provide electrical connection between the conductive layer and through holes, wherein: the core substrate is a multi-layer core substrate composed of three or more layers and including a thick conductive layer as an inner layer, and a conductive layer as a surface layer, the conductive layer of each inner layer of the core substrate and the conductive layer of each surface layer are a conductive layer for power layer or a conductive layer for grounding, and the core substrate is so constructed that the thick conductive layer as an inner layer comprises first and second thick conductive layers formed on respective sides of a metallic plate which is electrically insulated by a resin layer, and the conductive layer as a surface layer is formed outside the conductive layer as an inner layer interposed by a resin layer.