Patent ID: 8923009

Claim:
A substrate with built-in electronic component, comprising; a core layer having a storage portion penetrating the core layer; an electronic component stored in the storage portion; a synthetic resin filler filling a space between the electronic component and inner walls of the storage portion, the synthetic resin filler having a higher moisture absorbency than that of the core layer; and two or more pairs of an insulating layer and a conductive layer disposed on two opposite surfaces of the core layer in a thickness direction, the insulating layers being made of a synthetic resin, the conductive layers being made of a metal, wherein, of the two or more pairs of the insulating layer and the conductive layer disposed on at least one of two opposite surfaces of the core layer in a thickness direction, a conductive layer closest to the core layer has at least one first penetrating hole formed therein so as to overlap at least part of an opening edge of the storage portion in a plan view; wherein, of the two or more pairs of the insulating layer and the conductive layer, a conductive layer other than the conductive layer closest to the core layer has at least one second penetrating hole formed therein so as to overlap at least part of the first penetrating hole in a plan view.