Wiring substrate including projecting part having electrode pad formed thereon

1. A wiring substrate comprising:

an insulating layer having a first surface on which a projecting part is formed;

an electrode pad being formed on the projecting part and including a first electrode pad surface and a second electrode pad surface on a side opposite to the first electrode pad surface;

a via wiring connected to the second electrode pad surface;

a through-hole formed in the insulating layer, the through-hole penetrating the insulating layer, exposing the second electrode pad surface, and having the via wiring formed therein; and

a metal layer extending from the through-hole to a second surface of the insulating layer opposite to the first surface of the insulating layer;

wherein the metal layer includes the via wiring formed in the through-hole and a wiring pattern formed on the second surface of the insulating layer,

wherein the first electrode pad surface is exposed from the projecting part of the insulating layer,

wherein the first electrode pad surface is flat and parallel with the first surface of the insulating layer,

wherein the second electrode pad surface is covered by the insulating layer,

wherein a cross-section of the projecting part is a tapered shape,

wherein one side of the cross-section toward the first electrode pad surface is narrower than another side of the cross-section toward the first surface of the insulating layer,

wherein the insulating layer and the projecting part are integrally formed with the same insulating resin,

wherein a side surface of the electrode pad is exposed from the projecting part.

2. The wiring substrate as claimed in claim 1 , wherein a multilayer structure including a wiring layer and another insulating layer is formed on the second surface of the insulating layer.

3. A semiconductor package comprising:

the wiring substrate of claim 1 .

4. A wiring substrate comprising:

an insulating layer having a first surface on which a projecting part is formed;

an electrode pad being formed on the projecting part and including a first electrode pad surface and a second electrode pad surface on a side opposite to the first electrode pad surface;

a via wiring connected to the second electrode pad surface;

a through-hole formed in the insulating layer, the through-hole penetrating the insulating layer, exposing the second electrode pad surface, and having the via wiring formed therein; and

a metal layer extending from the through-hole to a second surface of the insulating layer opposite to the first surface of the insulating layer;

wherein the metal layer includes the via wiring formed in the through-hole and a wiring pattern formed on the second surface of the insulating layer,

wherein the first electrode pad surface is exposed from the projecting part of the insulating layer,

wherein the first electrode pad surface is flat and parallel with the first surface of the insulating layer,

wherein the second electrode pad surface is covered by the insulating layer,

wherein a cross-section of the projecting part is a tapered shape,

wherein one side of the cross-section toward the first electrode pad surface is narrower than another side of the cross-section toward the first surface of the insulating layer,

wherein the insulating layer and the projecting part are integrally formed with the same insulating resin,

wherein at least a part of a side surface of the electrode pad is covered by the projecting part.

5. The wiring substrate as claimed in claim 4 ,

wherein an entire surface of the side surface of the electrode pad is covered by the projecting part.

6. The wiring substrate as claimed in claim 5 ,

wherein the projecting part includes a first projecting surface that is positioned on a same plane as the first electrode pad surface,

wherein the first projecting surface of the projecting part is formed in a periphery of the first electrode pad surface in a plan view.

7. The wiring substrate as claimed in claim 5 , wherein the first electrode pad surface is in a position that is more recessed with respect to a tip of the projecting part projecting farthest from the first surface of the insulating layer.

8. The wiring substrate as claimed in claim 4 , wherein a multilayer structure including a wiring layer and another insulating layer is formed on the second surface of the insulating layer.

9. A semiconductor package comprising:

the wiring substrate of claim 4 .