Method for producing wiring substrate

A method for producing a wiring substrate comprising an insulation substrate and a wiring layer having a predetermined wiring pattern and provided on the insulation substrate, the method comprising steps of:

• (a) preparing a seeded substrate comprising:
• the insulation substrate;
• a conductive undercoat layer provided on the insulation substrate and having a hydrophilic surface;
• a conductive seed layer provided on a first region of the surface of the undercoat layer, the first region having a predetermined pattern corresponding to the wiring pattern;
• and
• a water-repellent layer provided on a second region directly on the surface of the undercoat layer, the second region being a region other than the first region;
• (b) forming a metal layer on a surface of the seed layer, wherein a voltage is applied between an anode and the seed layer while a solid electrolyte membrane containing a metal ion-containing solution being disposed between the seeded substrate and the anode, and the solid electrolyte membrane and the seed layer being pressed into contact with each other;
• and
• (c) etching the water-repellent layer and the undercoat layer,
• wherein the undercoat layer includes a metal layer of at least one of Al or Cr, the metal layer having a natural oxide film on a surface thereof, and
• the water-repellent layer is not formed on the surface of the seed layer.