Abstract: A printed wiring board includes a first conductor layer, a resin insulating layer having an opening, a second conductor layer including a seed layer and an electrolytic plating layer formed on the seed layer, and a via conductor including the seed and electrolytic plating layers and connecting the first and second conductor layers. The seed layer has a first portion on the surface of the insulating layer, a second portion on an inner wall surface in the opening of the insulating layer, and a third portion on a portion of the first conductor layer exposed by the opening of the insulating layer such that the first portion is thicker than the second and third portions, and the insulating layer includes resin and inorganic particles including first particles forming the inner wall surface and second particles embedded in the insulating layer and having shapes different from shapes of the first particles.

Abstract: A printed wiring board includes a first conductor layer, a resin insulating layer having an opening, a second conductor layer including a seed layer and an electrolytic plating layer formed on the seed layer, and a via conductor including the seed layer and the electrolytic plating layer and connecting the first conductor and second conductor layers. The seed layer has a first portion on the surface of the insulating layer, a second portion on an inner wall surface in the opening of the insulating layer, and a third portion on a portion of the first conductor layer exposed by the opening of the insulating layer such that the first portion is thicker than the second portion and the third portion, the second portion has a first film and a second film electrically connected to the first film, and a portion of the first film is formed on the second film.

Abstract: A printed wiring board includes an insulating layer, a conductor layer formed on the insulating layer and including one or more conductor circuits, an insulating adhesive layer covering a surface of the conductor layer and a part or parts of the insulating layer exposed from the conductor layer, and a resin insulating layer formed on the insulating layer and the conductor layer such that the insulating adhesive layer is sandwiched between the conductor layer and the resin insulating layer. The insulating adhesive layer includes a first portion covering an upper surface of the one or more conductor circuits and a second portion covering a side surface of the one or more conductor circuits and a thickness of the first portion is greater than a thickness of the second portion.

Abstract: A printed wiring board includes a first conductor layer, an insulating layer formed on the first conductor layer, a second conductor layer formed on the insulating layer, and a via conductor formed in the insulating layer such that the via conductor is connecting the first and second conductor layers. The insulating layer has opening exposing portion of the first conductor layer such that the via conductor is formed in the opening, the second conductor layer and via conductor are formed such that the second conductor layer and via conductor include a seed layer and an electrolytic plating layer on the seed layer, and the insulating layer includes resin and inorganic particles dispersed in the resin such that the particles include first particles forming inner wall surface in the opening and second particles embedded in the insulating layer and the first particles have shapes different from shapes of the second particles.