Patent ID: 9603248
Date: 2017-03-21
CPC Classifications: H05K

Claim:
1. A wiring board, comprising: a board structure comprising a core insulation layer, a first conductive layer formed on a first surface of the core insulation layer, a first laminated structure formed over the first surface of the core insulation layer and the first conductive layer, a second conductive layer formed on a second surface of the core insulation layer on an opposite side of the core insulation layer with respect to the first surface of the core insulation layer, and a second laminated structure formed over the second surface of the core insulation layer and the second conductive layer; and a stacked conductor structure formed in the board structure and comprising a through-hole conductor penetrating through the core insulation layer and a via conductor formed in the first laminated structure, wherein the through-hole conductor has a though-hole portion formed in a through hole penetrating through the core insulation layer and a first land portion formed on the first surface of the core insulation layer such that the through-hole portion has a first end portion, a second end portion and a narrowed portion formed between the first end portion and the second end portion, the first conductive layer includes the first land portion of the through-hole conductor, the first laminated structure includes an interlayer insulation layer in which the via conductor is formed, the via conductor in the first laminated structure is stacked on the first land portion of the through-hole conductor such that the stacked conductor structure comprising the through-hole conductor and the via conductor is formed through the core insulation layer and the interlayer insulation layer of the first laminated structure, the stacked conductor structure is formed such that the through-hole portion of the through-hole conductor has the first end portion connected to the first land portion of the through-hole conductor, that the first end portion of the through-hole portion has a width which is set greater than a width of a bottom surface of the via conductor connected to the first land portion of the through-hole conductor and smaller than a width of a top surface of the via conductor in the first laminated structure and that the narrowed portion has a width which is set smaller than the width of the bottom surface of the via conductor connected to the first land portion of the through-hole conductor, the stacked conductor structure comprises a plating material filling the through hole in the core insulation layer, the second laminated structure comprises an interlayer insulation layer and a via conductor formed in the interlayer insulation layer of the second laminated structure, the through-hole conductor has a second land portion formed on the second surface of the core insulation layer and connected to the second end portion of the through-hole portion, the second conductive layer includes the second land portion of the through-hole conductor, the through-hole portion of the through-hole conductor becomes narrower from the first end portion toward the narrowed portion and from the second end portion toward the narrowed portion, the stacked conductor structure includes the through-hole conductor, the via conductor in the first laminated structure stacked on the first land portion of the through-hole conductor, and the via conductor in the second laminated structure stacked on the second land portion of the through-hole conductor such that the narrowed portion has the width which is set smaller than the width of the bottom surface of the via conductor connected to the second land portion of the through-hole conductor, and the second end portion of the through-hole conductor has a width which is set greater than the width of the bottom surface of the via conductor connected to the second land portion of the through-hole structure and smaller than a width of a top surface of the via conductor connected to the second land portion of the through-hole structure.