Method for producing wiring substrate

Abstract

The present disclosure provides a method for producing a wiring substrate. A seeded substrate including an insulation substrate, a conductive undercoat layer, and a conductive seed layer provided in a first region, in that order, is first prepared. An insulation layer covering the seed layer and the undercoat layer is then formed. Subsequently, the insulation layer is etched to expose a surface of the seed layer and form a remaining insulation layer covering the undercoat layer in the second region. Subsequently, a voltage is applied between an anode and the seed layer while a solid electrolyte membrane containing a metal ion-containing aqueous solution disposed between the seed layer and the anode and the membrane and the seed layer pressed into contact with each other, thereby a metal layer being formed on the surface of the seed layer. Thereafter, the remaining insulation layer is removed and the undercoat layer is etched.