Wiring board and method for manufacturing the same

A method for manufacturing a wiring board, comprising:

• preparing a first substrate which has a first opening portion penetrating through the first substrate;
• forming on a surface of the first substrate a built-up layer comprising a plurality of interlayer resin insulation layers and a plurality of conductive circuits;
• forming in the built-up layer a second opening portion communicating with the first opening portion of the first substrate such that the first opening portion and the second opening portion form a penetrating hole opened to an outermost surface of the built-up layer on an opposite side of the first substrate;
• placing a support board to the build-up layer such that the support board closes the second opening portion of the build-up layer;
• accommodating in the second opening portion of the built-up layer an interposer comprising a wiring layer, the wiring layer of the interposer comprising a plurality of second conductive circuits configured to be connected to a plurality of semiconductor elements;
• filling a filler in the penetrating hole such that the interposer is held in the second opening portion of the built-up layer;
• and
• removing the support board from the build-up layer,
• wherein the forming of the second opening portion in the built-up layer includes forming a tapered opening portion such that the tapered portion forms the second opening portion tapering toward the outermost surface of the built-up layer.