Method of Manufacturing Wiring Substrate

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

• preparing a laminated plate in which a metal layer and an insulating layer are laminated;
• adhering the laminated plate to a first support body with the metal layer facing the first support body;
• forming a first wiring layer including vias that extend through the insulating layer and first pads exposed from a first surface of the insulating layer;
• separating from the first support body a multilayer structure including the metal layer, the insulating layer, and the first wiring layer;
• adhering the multilayer structure to a second support body with the first wiring layer facing the second support body;
• removing the metal layer;
• forming a plurality of second wiring layers including second pads that are connected to the vias and exposed from a second surface of the insulating layer that is opposite to the first surface;
• and
• separating the insulating layer, the first wiring layer, and the plurality of second wiring layers from the second support body to obtain the wiring substrate.