Patent ID: 8242379

Claim:
A multilayered printed wiring board comprising: a multilayered core substrate comprising a plurality of insulation layers and at least one stacked via structure formed through the plurality of insulation layers, the stacked via structure comprising a plurality of vias formed in the plurality of insulation layers, respectively; and a build-up structure formed over the multilayered core substrate and comprising a plurality of interlaminar insulation layers and a plurality of conductor circuits, each of the interlaminar insulation layers comprising a resin material without a core material, wherein the plurality of insulation layers in the multilayered core substrate has a number of layers which is 2N+1 where N is a natural number, each of the insulation layers in the multilayered core substrate comprises a core material impregnated with a resin, the vias in the stacked via structure are formed in a tapered shape and comprise a first via group formed in N+1 layers of the insulation layers and a second via group formed in N layer or layers of the insulations layers, and the vias in the stacked via structure are tapered such that the first via group and the second via group face in opposite directions.