Method for producing package substrate for loading semiconductor device

A method for manufacturing a package substrate for mounting a semiconductor device comprising an insulating layer and a wiring conductor provided on the insulating layer, the method comprising:

• forming a first substrate comprising a first metal layer that has a thickness of 1 μm to 70 μm and that is peelable from the core resin layer, a first insulating resin layer, and a second metal layer in this order on one side or both sides of a core resin layer;
• forming a non-through hole reaching a surface of the first metal layer on a surface of the first substrate, carrying out electrolytic copper plating and/or electroless copper plating on an inner wall of the non-through hole, and connecting the second metal layer and the first metal layer;
• forming a second substrate by heating and pressurizing a laminate formed by arranging a second insulating resin layer and a third metal layer in this order on a surface of the second metal layer of the first substrate;
• forming a non-through hole reaching the surface of the second metal layer on a surface of the second substrate, carrying out electrolytic copper plating and/or electroless copper plating on an inner wall of the non-through hole, and connecting the second metal layer and the third metal layer;
• peeling off, from the core resin layer, a third substrate comprising the first metal layer, the first insulating resin layer, the second metal layer, the second insulating resin layer, and the third metal layer in this order;
• and
• patterning the first metal layer and the third metal layer of the third substrate to form the wiring conductor.