Semiconductor device having a mount board

1. A semiconductor device comprising:

a module board mounting thereon an electric component and including a plug at an edge of said module board; and

a mount board including a socket which is adapted to said plug and formed on a surface portion of said mount board for mounting thereon said module board via said plug, said socket including a bottom surface in contact with the surface portion,

wherein said surface portion of said mount board includes therein a heat radiation layer in contact with the bottom surface of said socket.

2. The semiconductor device according to claim 1 , wherein said mount board comprises heat radiation fins fixed to said surface portion.

3. A semiconductor device comprising:

a module board mounting thereon an electric component and including a plug at an edge of said module board; and

a mount board including a socket which is adapted to said plug and formed on a surface portion of said mount board for mounting thereon said module board via said plug, said socket including a bottom surface in contact with the surface portion,

wherein said surface portion of said mount board includes therein a heat radiation layer in contact with the bottom surface of said socket, wherein said heat radiation layer is other than an electric terminal of said module board.

4. The semiconductor device according to claim 3 , wherein said heat radiation layer comprises copper.

5. The semiconductor device according to claim 3 , wherein said socket comprises a heat radiation guide plate in contact with a side surface of said socket.

6. The semiconductor device according to claim 3 , further comprising an interconnection area, wherein said heat radiation layer is disposed around said interconnection area.

7. The semiconductor device according to claim 3 , further comprising an uppermost insulating layer, wherein said heat radiation layer replaces a portion of said uppermost insulating layer.

8. The semiconductor device according to claim 3 , wherein said heat radiation layer includes a planar shape sufficient to encompass substantially an entire bottom surface of said socket.

9. The semiconductor device according to claim 3 , wherein said electric component comprises a memory device.

10. A motherboard comprising:

a module board mounting thereon an electric component and comprising a plug at an edge of said module board;

a socket adapted to said plug and formed on a surface portion of said motherboard for mounting thereon said module board via said plug, said socket including a bottom surface in contact with the surface portion; and

a heat radiation layer formed in said surface portion of said motherboard and in contact with the bottom surface of said socket, wherein said heat radiation layer is other than an electric terminal of said module board.

11. The motherboard according to claim 10 , wherein said socket comprises a heat radiation guide plate in contact with a side surface of said socket.

12. The motherboard according to claim 10 , wherein said electric component comprises a memory device.

13. The motherboard according to claim 11 , wherein said electric component comprises a memory device.

14. The semiconductor device according to claim 1 , wherein said socket comprises a heat radiation guide plate in contact with a side surface of said socket.

15. The semiconductor device according to claim 14 , wherein said heat radiation guide plate has a thermal conductivity of 1 watt/meter K or above.

16. The semiconductor device according to claim 14 , wherein said heat radiation guide plate is in contact with said surface portion of said mount board.

17. The semiconductor device according to claim 1 , wherein said mount board comprises a mount for a cooling fan for cooling said heat radiation guide plate.

18. An apparatus comprising:

a module board comprising an edge area, a center area, and a plurality of plug terminals provided in the edge area;

at least one electronic device mounted on the center area and electrically connected to the plug terminals;

a socket comprising a concave portion and a plurality of socket terminals provided on a surface of the concave portion, the module board being inserted into the concave portion such that the plug terminals are in contact with the socket terminals;

a mount board on which the socket is mounted; and

a heat radiation layer partially embedded in the mount board such that a top surface of the heat radiation layer is substantially coplanar with a top surface of the mount board, the heat radiation layer being larger in heat conductivity than the mount board and intervening at least a part thereof between the mount board and the socket with an electrical isolation from each of the socket terminals of the socket.

19. The apparatus as claimed in claim 18 , wherein the mount board includes a plurality of via holes that are electrically connected to the socket terminals of the socket, the heat radiation layer being configured to sandwich the via holes.

20. The apparatus as claimed in claim 18 , wherein the socket further comprises a side surface, the apparatus further comprising a heat radiation guide plate directly connected with the side surface of the socket and the heat radiation layer.

21. The semiconductor device according to claim 1 , wherein the mount board includes an insulating layer, the socket is formed over the insulating layer, and the heat radiation layer is formed between the socket and the insulating layer.

22. The semiconductor device according to claim 1 , wherein the socket includes a top surface which is opposite the bottom surface, the top surface including an opening for inserting the plug of the module board.

23. The semiconductor device according to claim 1 , further comprising a plurality of electrodes formed at a bottom of the socket,

wherein the surface portion of the mount board further comprises an interconnection area which includes a plurality of interconnection plugs connected to the plurality of electrodes, and

wherein the bottom surface of the socket is in contact with the interconnection area and the heat radiation layer is formed on a side of the interconnection area and in the same plane as the interconnection area.