Abstract: An open pad structure includes an insulating layer; a first pad disposed on the insulating layer; a second pad disposed on the insulating layer and spaced apart from the first pad; and a passivation layer disposed on the insulating layer, covering the first and second pads, and having an opening for opening at least a portion of each of the first and second pads. The passivation layer covers the insulating layer between the first and second pads in the opening, and t1 and t2 satisfy t1>t2, in which a thickness of a region of the passivation layer other than the opening, and t2 is a thickness of a region of the passivation layer between the first and second pads.

Abstract: Disclosed herein is a method of manufacturing a multilayer type coreless substrate, the method including: (A) preparing a carrier substrate including at least one copper foil formed on one surface or both surfaces of an insulating surface; (B) forming a coreless printed circuit precursor on one surface or both surfaces of the carrier substrate; (C) separating the carrier substrate; (D) performing a polishing cutting process on the coreless printed circuit precursor; and (E) laminating a plurality of other insulating layers on a flat outer surface of the coreless printed circuit precursor, the plurality of other insulating layers sequentially including other circuit layers and other pillars.