Abstract: A printed wiring board includes a core substrate including an insulative substrate, a first conductive layer formed on first surface of the insulative substrate, and a second conductive layer formed on second surface of the insulative substrate, a first buildup laminated on first surface of the core and including an interlayer insulation layer, a conductive layer formed on the insulation layer, and a via conductor penetrating through the insulation layer and connected to the conductive layer, and a second buildup laminated on second surface of the core and including an interlayer insulation layer, a conductive layer formed on the interlayer insulation layer, and a via conductor penetrating through the insulation layer and connected to the conductive layer. The insulation layer of the first buildup has thermal expansion coefficient set higher than thermal expansion coefficient of the insulation layer of the second buildup.

Abstract: A printed wiring board includes a core substrate, a first conductive layer on a first surface of the substrate, a second conductive layer on a second surface of the substrate, and a through-hole conductor connecting the first and second conductive layers. The substrate has an insulation structure and a metal layer, the metal layer has opening through which the conductor passes and has side wall recessed into the metal layer and forming the opening, the structure has first resin layer on one side of the metal layer, second resin layer on the opposite side and filler filling the opening, the conductor has first portion in the first layer and second portion in the second layer, the first and second portions are connected in the filler, the first portion is tapered from the first toward second conductive layers, and the second portion is tapered from the second toward first conductive layers.

Abstract: A printed wiring board includes an interlayer insulation layer, first pads positioned to mount a semiconductor element and forming a first pad group on the insulation layer, second pads forming a second pad group on the insulation layer and positioned along a peripheral portion of the first group, a first solder-resist layer formed on the insulation layer and having first openings exposing the first pads, respectively, and second openings exposing the second pads, respectively, conductive posts formed on the second pads through the second openings of the first solder-resist layer, respectively, and a second solder-resist layer formed on the first solder-resist layer and having a third opening exposing the first pads and fourth openings exposing surfaces of the posts, respectively. The second openings have a diameter greater than a diameter of the posts, and the second solder-resist layer is filling gaps formed between the second openings and the posts.

Abstract: A method for manufacturing a printed wiring board includes preparing a core substrate having a first surface and a second surface on the opposite side of the first surface, forming on the first-surface side of the substrate a first opening portion tapering from the first toward second surface, forming on the second-surface side of the substrate a second opening portion tapering from the second toward first surface, forming a third opening portion such that a penetrating hole formed of the first opening portion, the second opening portion and the third opening portion connecting the first and second opening portions is formed in the substrate, forming a first conductor on the first surface of the substrate, forming a second conductor on the second surface of the substrate, and filling a conductive material in the penetrating hole such that a through-hole conductor connecting the first and second conductors is formed.

Abstract: A method for manufacturing a printed wiring board includes preparing a core substrate having a metal layer having a first penetrating hole and insulation layers formed on the metal layer such that the metal layer is interposed between the insulation layers, forming in the core substrate a second penetrating hole having a first opening portion aligned with the first penetrating hole on a first-surface side of the core substrate and a second opening portion aligned with the first penetrating hole on a second-surface side of the core substrate, forming a first conductor on a first surface of the core substrate, forming a second conductor on a second surface of the core substrate on the opposite side of the first surface of the core substrate, and filling a conductive material in the second penetrating hole such that a through-hole conductor connecting the first conductor and the second conductor is formed.

Abstract: A method for manufacturing a printed wiring board includes preparing a metal sheet having metal members and connectors joining the metal members, forming a structure having core substrates which are connected through the connectors and which have insulation structure portions covering the metal members, respectively, cutting the connectors in the structure such that an independent core substrate having a recessed portion is formed and a respective one of the connectors is removed from the independent core substrate, and covering the recess portion of the independent core substrate with a resin. The covering of the recess portion includes either forming an interlayer insulation layer on a surface of the independent core substrate or forming interlayer insulation layers on opposing surfaces of the independent core substrate.

Abstract: A printed wiring board has a metal layer, a resin structure having a first resin layer portion formed on a first surface of the metal layer, a second resin layer portion formed on a second surface of the metal layer, and a filler resin portion filling an opening portion of the metal layer, a first circuit formed on the first resin portion, a second circuit formed on the second resin portion, and a through-hole conductor formed through the first resin, filler resin and second resin portions and connecting the first and second circuits. The through-hole conductor has a first portion narrowing from the first circuit toward the second resin portion and a second portion narrowing from the second circuit toward the first resin portion, and the first portion is connected to the second portion at a connected position shifted from the middle point of the thickness of the metal layer.

Abstract: A printed wiring board including a core substrate having a metal layer, a first resin insulation layer on a surface of the metal layer and a second resin insulation layer on the opposite surface of the metal layer, a first conductive circuit formed on the first layer, a second conductive circuit formed on the second layer, and a through-hole conductor formed in a penetrating hole through the substrate and connecting the first and second circuits. The metal layer has an opening filled with a filler resin, the penetrating hole has a first opening in the first layer, a second opening in the second layer and a third opening in the filler resin, the first opening tapers toward the filler resin, the second opening tapers toward the filler resin, and the third opening is connecting the first and second openings.