A through-hole electrode substrate includes a substrate including a through-hole extending from a first aperture of a first surface to a second aperture of a second surface, an area of the second aperture being larger than that of the first aperture, the through-hole having a minimum aperture part between the first aperture and the second aperture, wherein an area of the minimum aperture part in a planer view is smallest among a plurality of areas of the through-hole in a planer view, a filler arranged within the through-hole, and at least one gas discharge member contacting the filler exposed to one of the first surface and the second surface.

In a method for manufacturing a multilayer substrate for having a BGA-type component thereon, a conductive through hole for restricting a signal interference and a resist film are formed on the multilayer substrate, an occurrence of a fault caused by a residual of a resist in the conductive through hole is reduced. In the method for manufacturing the multilayer substrate for having the BGA-type component thereon, a step of forming the resist film includes an applying step of applying a photosensitive resist to an entirety of a front surface portion of a base. The applying step is performed while restricting the resist from entering the conductive through hole by supplying a high pressure air to a rear surface of the base to pass through the conductive through hole using an air supply mechanism.

A through-hole electrode substrate includes a substrate including a through-hole extending from a first aperture of a first surface to a second aperture of a second surface, an area of the second aperture being larger than that of the first aperture, the through-hole having a minimum aperture part between the first aperture and the second aperture, wherein an area of the minimum aperture part in a planar view is smallest among a plurality of areas of the through-hole in a planar view, a filler arranged within the 10 through-hole, and at least one gas discharge member contacting the filler exposed to one of the first surface and the second surface.

A printed wiring board includes an uppermost insulating layer, first pads positioned to mount an IC chip on the insulating layer, second pads positioned to mount a second printed wiring board on the insulating layer, metal posts formed on the second pads, respectively, such that the metal posts mount the second board over the chip, and a solder resist layer formed on the uppermost insulating layer and having first and second openings such that the first openings exposes the first pads and that the second openings exposes the second pads, respectively. The metal posts are formed such that each of the metal posts has a diameter which is smaller than a diameter of each of the second opening portions, and the second opening portions are formed such that the diameter of each of the second opening portions is smaller than a diameter of each of the second pads.

In a wiring board, on an insulating layer of an outermost layer, there are provided a plurality of strip-shaped wiring conductors which are partially provided with semiconductor element connection pads to which electrode terminals of a semiconductor element are connected, at positions which prevent the semiconductor element connection pads adjacent to each other from being laterally arranged, and a solder resist layer having openings for individually exposing the semiconductor element connection pads is adhered on the insulating board as the outermost layer and on the strip-shaped wiring conductors, wherein the solder resist layer internally contains an insulating filler, and the insulating filler is sunk below the upper surfaces of the strip-shaped wiring conductors.

In a wiring substrate, formation of voids due to underfill filling failure is suppressed. A wiring substrate includes an insulating base layer, an insulating layer laminated on the base layer, and an electrically conductive connection terminal projecting from the insulating layer inside an opening. The insulating layer has a first surface with an opening, and a second surface located within the opening and being concave toward the base layer in relation to the first surface. The second surface extends from the first surface to the connection terminal inside the opening. On a cut surface which is a flat surface extending along a lamination direction in which the insulating layer is laminated on the base layer, an angle which is larger than 0 but smaller than 90 is formed between a normal line extending from an arbitrary point on the second surface toward the outside of the insulating layer and a parallel line extending from the arbitrary point toward the connection terminal in parallel to the first surface.