Wiring substrate and method of manufacturing the same

A method of manufacturing a wiring substrate, comprising the steps of:

• forming a metal layer over a whole of a substrate;
• forming a first resist in which an opening portion is provided on the metal layer;
• forming a partial cover plating layer in the opening portion of the first resist by a plating;
• removing the first resist;
• forming a second resist which covers a whole of the partial cover plating layer and has a pattern for patterning the metal layer;
• and
• forming a wiring pattern, on a part of which the partial cover plating layer is provided upright, by etching the metal layer while using the second resist as a mask.

A wiring substrate, comprising:

• a substrate in which a through hole is provided;
• a resin filled in the through hole;
• a pad wiring portion composed of a through-hole plating layer which is patterned, and is formed to extend from an area between an inner surface of the through hole and the resin to both surface sides of the substrate respectively, and a partial cover plating layer having pad-like shape, which is formed on the resin in the through hole and the through-hole plating layer on both surface sides of the substrate respectively;
• and
• a wiring pattern formed of an identical layer as the through-hole plating layer and patterned on both surface sides of the substrate respectively such that the wiring pattern is separated from the pad wiring portion;
• wherein the pad wiring portions on both surface sides of the substrate are connected mutually via the through-hole plating layer, and a film thickness of the wiring pattern is set thinner than a film thickness of the pad wiring portion.