Semiconductor device having conducting portion of upper and lower conductive layers

1. A semiconductor device comprising:

a base plate having a plurality of peripheral surfaces;

at least one first conductive layer carried by the base plate;

a semiconductor constructing body which is formed above the base plate, and which includes a semiconductor substrate and a plurality of external connecting electrodes carried by the semiconductor substrate;

an insulating layer which is formed above the base plate and around the semiconductor constructing body, and which has a plurality of peripheral surfaces and a same peripheral shape and size as the base plate;

a plurality of second conductive layers which are formed above the insulating layer and which are electrically connected to the external connecting electrodes of the semiconductor constructing body; and

a vertical conducting portion which is formed on at least one of the peripheral surfaces of the insulating layer and on at least one of the peripheral surfaces of the base plate corresponding to said at least one of the peripheral surfaces of the insulating layer, and which electrically connects at least one said first conductive layer and at least one of the second conductive layers.

2. A device according to claim 1 , wherein the vertical conducting portion comprises: (i) a groove formed in said at least one of the peripheral surfaces of the insulating layer and in said at least one of the peripheral surfaces of the base plate corresponding to said at least one of the peripheral surfaces of the insulating layer, and (ii) a vertical conducting layer formed in the groove.

3. A device according to claim 2 , wherein an inner surface of the groove continues to the peripheral surfaces of the insulating layer and base plate.

4. A device according to claim 2 , wherein an inner surface of the groove has a semi-circular planar shape.

5. A device according to claim 1 , wherein a ground layer is formed on an upper surface of the base plate and electrically connected to the vertical conducting portion.

6. A device according to claim 5 , wherein the semiconductor substrate of the semiconductor constructing body is adhered to the ground layer by a conductive adhesive layer.

7. A device according to claim 1 , wherein a ground layer is formed on a lower surface of the base plate and electrically connected to the vertical conducting portion.

8. A device according to claim 1 , wherein said at least one first conductive layer is formed on a lower surface of the base plate, and a portion of the first conductive layer is electrically connected to the vertical conducting portion.

9. A device according to claim 8 , wherein the first conductive layer comprises a plurality of first conductive layer sections including lowermost conductive layer sections, at least one of the lowermost conductive layer sections has a connecting pad portion, and the lowermost conductive layer sections are covered with a lower overcoat film except for the connecting pad portion of said at least one of the lowermost conductive layer sections.

10. A device according to claim 9 , further comprising at least one electronic part formed on a lower surface of the lower overcoat film and electrically connected to at least one said connecting pad portion of the lowermost conductive layer sections of the first conductive layer.