Semiconductor device

1. A semiconductor device comprising:

a semiconductor substrate having a first main surface and a second main surface opposite to the first main surface;

a first conductive layer disposed above the second main surface;

a second conductive layer passing through the semiconductor substrate from the first main surface to the second main surface, said second conductive layer being connected to the first conductive layer;

an organic insulation film disposed to contact with the first conductive layer; and

a first insulation layer disposed to contact with the organic insulation film,

wherein said second conductive layer is entirely formed in a two-layered structure,

said second conductive layer includes a first portion passing through the semiconductor substrate,

said first portion contacts with the semiconductor substrate through the organic insulation film and the first insulation layer,

said second conductive layer includes a second portion contacting with the first main surface through the organic insulation film and the first insulation layer, and

said second portion has a layer thickness greater than that of the first portion.

2. The semiconductor device according to claim 1 , wherein said organic insulation film is disposed to cover a surface of the first conductive layer above the second main surface side,

said organic insulation film includes an opening portion exposing the surface of the first conductive layer above the second main surface side, and

said second conductive layer is connected to the first conductive layer through the opening portion.

3. The semiconductor device according to claim 1 , further comprising a second insulation layer disposed to cover the second main surface,

wherein said first conductive layer is disposed on the second insulation layer.

4. The semiconductor device according to claim 1 , wherein said first conductive layer includes a third conductive layer disposed on the second main surface and a fourth conductive layer disposed on the third conductive layer, and

said second conductive layer is connected to the fourth conductive layer.

5. The semiconductor device according to claim 1 , wherein said second conductive layer is formed of a metal plating layer and a seed metal layer, and

said seed metal layer is disposed to contact with the organic insulation film.

6. The semiconductor device according to claim 1 , wherein said first portion vertically passes through the semiconductor substrate, and

said second portion extends horizontally over the first main surface perpendicular to the first portion.

7. The semiconductor device according to claim 5 , wherein said seed metal layer has a uniform thickness throughout the second conductive layer.