Wiring board with through wiring

1. A wiring board comprising:

a substrate body provided with a through hole penetrating the substrate body from one surface to another surface of the substrate body; and

a through wiring formed in the through hole and including

a first metal layer that is formed on a part of an inner side surface of the through hole at the one surface side,

a first wiring layer that covers the first metal layer to fill a part of the through hole at the one surface side,

a second metal layer that is continuously formed on the rest part of the inner side surface of the through hole at the other surface side and on an end portion of the first wiring layer at the other surface side, and

a second wiring layer that covers the second metal layer to fill a part of the through hole at the other surface side,

the second metal layer being interposed between the first wiring layer and the second wiring layer to isolate the first wiring layer and the second wiring layer, and the first wiring layer and the second wiring layer being electrically connected in the through hole via the second metal layer.

2. The wiring board according to claim 1 ,

wherein the first wiring layer is provided with a concave portion that is open toward the other surface side at the end portion of the first wiring layer at the other surface side in the through hole, and

wherein the second wiring layer is provided with a protruding portion that protrudes toward the one surface side at an end portion of the second wiring layer at the one surface side in the through hole, the protruding portion fitting in the concave portion.

3. The wiring board according to claim 1 ,

wherein the through wiring further includes

a first adhesion layer provided between the substrate body and the first metal layer, and

a second adhesion layer provided between the substrate body and the second metal layer, and between the end portion of the first wiring layer at the other surface side and the second metal layer, the first wiring layer and the second wiring layer being electrically connected with each other via the second adhesion layer and the second metal layer in the through hole.

4. The wiring board according to claim 3 ,

wherein the material of the substrate body is silicon, and an inner side surface of the through hole is covered by a silicon oxide film,

wherein the first adhesion layer is made of material whose adhesion to the silicon oxide film is better than the adhesion of the first metal layer to the silicon oxide film, and

wherein the second adhesion layer is made of material whose adhesion to the silicon oxide film is better than the adhesion of the second metal layer to the silicon oxide film.

5. The wiring board according to claim 1 ,

wherein the first wiring layer has a structure in which a plurality of conductive layers are stacked on an end portion of the second wiring layer at the one surface side.

6. The wiring board according to claim 1 ,

wherein the thickness of the first metal layer formed on an inner side surface of the through hole is formed to become thinner as it approaches a deeper portion of the through hole from the one surface side, and

wherein the thickness of the second metal layer formed on an inner side surface of the through hole is formed to become thinner as it approaches a deeper portion of the through hole from the other surface.