| abstract |
A novel structure capable of connecting electronic components with high reliability in a coreless type wiring board is provided. SOLUTION: An insulating layer 40, a pad P in which a side surface S1 and a lower surface S2 are embedded in the insulating layer 40, a metal post M formed on the upper surface of the pad P and having a constricted portion X at the base of the pad P; including. The height of the upper surface of the metal post M is higher than the height of the upper surface of the insulating layer 40, and the upper edge of the metal post is a curved surface portion C. [Selection] Figure 12 |