Printed wiring board and method for manufacturing the same

A printed wiring board comprising:

• a plurality of layers of a wiring base body, each of the plurality of layers including:
• an insulating resin film having a first main surface that is an uppermost surface of the insulating resin film and a second main surface that is a lowermost surface of the insulating resin film;
• a conductive post embedded in the insulating resin film that penetrates the insulating resin film from the first main surface to the second main surface;
• and
• a wiring (1) embedded in the insulating resin film, (2) extending in a direction parallel to the second main surface, and (3) exposed to the second main surface, wherein
• the insulating resin film has a multi-layer structure including a first layer with the first main surface and a second layer with the second main surface,
• the wiring being embedded in the second layer and not being embedded in the first layer,
• the first layer and the second layer are arranged alternately,
• a melting point of a constituent material of the first layer is lower than a melting point of a constituent material of the second layer,
• the conductive post has a wiring portion exposed to the second main surface and embedded in the second layer and a main body portion extending from the wiring portion to the first main surface through the second layer and the first layer,
• the main body portion has a monolithic composition,
• the wiring portion and the main body portion of the conductive post are constituted through plating,
• the plurality of layers includes a top layer of the plurality of layers and a bottom layer of the plurality of layers,
• the first layer and the second layer are alternately throughout the plurality of layers, including the top layer and the bottom layer, and
• the wiring and the wiring portion do not extend beyond the second main surface.