Wiring substrate and method for manufacturing the same

A wiring substrate, comprising:

• a plurality of insulating layers including a first insulating layer and a second insulating layer laminated on the first insulating layer;
• a plurality of conductive layers including a first conductive layer formed on the first insulating layer and including a pad and a second conductive layer formed on the second insulating layer;
• a coating film formed on the first conductive layer such that the coating film is covering the first conductive layer including the pad and improving adhesion between the first conductive layer and the second insulating layer;
• and
• a via conductor formed in the second insulating layer such that the via conductor is formed in a through hole penetrating through the second insulating layer and the coating film formed on the pad and connecting the pad of the first conductive layer and the second conductive layer,
• wherein the pad of the first conductive layer has a surface formed such that a root mean square roughness of the surface is in a range of 0.10 μm to 0.23 μm, and a peeling part is formed between the pad and the second insulating layer such that the peeling part is formed within 15 μm around an outer edge of the through hole on the surface of the pad.