Semiconductor device having stress relaxation sections

1. A semiconductor device comprising:

a semiconductor substrate including a first surface and a second surface corresponding to a back surface with respect to the first surface and having first through electrodes which extend through the first surface and the second surface;

a semiconductor chip over the first surface of the semiconductor substrate, the semiconductor chip is comprised of a same material as the semiconductor substrate and has a circuit element electrically connected to the first through electrodes;

a stress relaxing section including first conductors over the second surface of the semiconductor substrate and electrically connected to the first through electrodes of the semiconductor substrate and having flexibility, the stress relaxing section including a first insulator over the second surface of the semiconductor substrate so as to cover the side surfaces of the first conductors and the second surface of the semiconductor substrate, and having elasticity, the first conductors have columnar shape;

external connecting terminals over the stress relaxing section and connected to the first conductors respectively,

wherein each of the first conductors of the stress relaxing section has a third surface opposite to the second surface of the semiconductor substrate and electrically connected to a corresponding first through electrode, a fourth surface corresponding to a back surface with respect to the third surface and connected to a corresponding external connecting terminal, and a side surface that connects the third surface and the fourth surface,

wherein the semiconductor substrate, the semiconductor chip and the stress relaxing section are configured together as a semiconductor package,

wherein the semiconductor package is on a circuit board with the stress relaxing section facing the circuit board, a linear expansion coefficient of the circuit board being different than a linear expansion coefficient of the semiconductor substrate, and

wherein a planar size of the stress relaxing section and a planar size of the semiconductor substrate are the same; and

conductive films over the second surface of the semiconductor substrate, the conductive films each having a first portion connected to a corresponding first through electrode of the semiconductor substrate and a second portion connected to the third surface of a corresponding first conductor.

2. The semiconductor device according to claim 1 , wherein the first insulator comprises a resin.

3. The semiconductor device according to claim 1 , further including first conductive films over the first surface of the semiconductor substrate, and each having a first portion connected to a corresponding first through electrode of the semiconductor substrate and having a second portion electrically connected to the circuit element of the semiconductor chip.

4. The semiconductor device according to claim 3 , further including encapsulating layers among the semiconductor substrate and the semiconductor chip so as to cover the first conductive films.

5. The semiconductor device according to claim 4 , wherein the encapsulating layers comprise a resin.

6. The semiconductor device according to claim 3 , wherein the semiconductor chip includes second through electrodes, a fifth surface opposite to the first surface of the semiconductor substrate and a sixth surface corresponding to a back surface with respect to the fifth surface, and each of the second through electrodes extend through the fifth surface and the sixth surface and are electrically connected to the circuit element,

the semiconductor device further comprising connecting bumps between the first surface of the semiconductor substrate and the fifth surface of the semiconductor chip, each of said connecting bumps being connected to the second portion of a corresponding first conductive film of the semiconductor substrate and connected to a corresponding second through electrode the semiconductor chip.

7. The semiconductor device according to claim 1 , further including an encapsulator which covers the semiconductor chip and the first surface of the semiconductor substrate.

8. The semiconductor device according to claim 7 , wherein the encapsulator comprises a resin.

9. The semiconductor device according to claim 7 , wherein the encapsulator contains ceramic.

10. A semiconductor device comprising:

a semiconductor substrate including a first surface and a second surface corresponding to a back surface with respect to the first surface and having first through electrodes which extend through the first surface and the second surface;

semiconductor chips mounted over the first surface of the semiconductor substrate, each of said semiconductor chips being constituted of a material of the same kind as the semiconductor substrate and having a circuit element electrically connected to the first through electrodes;

stress relaxing sections including first conductors over the second surface of the semiconductor substrate and electrically connected to the first through electrodes of the semiconductor substrate and having flexibility, and including a first insulator over the second surface of the semiconductor substrate so as to cover the side surfaces of the first conductors and the second surface of the semiconductor substrate, and having elasticity; and

external connecting terminals provided over the stress relaxing sections and connected to the first conductors respectively,

wherein each of the first conductors of the stress relaxing sections has a third surface opposite to the second surface of the semiconductor substrate and electrically connected to the corresponding first through electrode, a fourth surface corresponding to a back surface with respect to the third surface and connected to the corresponding external connecting terminal, and a side surface that connects the third surface and the fourth surface, and

wherein a distance between the second surface of the semiconductor substrate and each of the external connecting terminals is greater than or equal to 50 μm.

11. A semiconductor device comprising:

a semiconductor substrate including a first surface and a second surface corresponding to a back surface with respect to the first surface and having first through electrodes which extend through the first surface and the second surface;

a semiconductor chip over the first surface of the semiconductor substrate, the semiconductor chip is comprised of a same material as the semiconductor substrate and has a circuit element electrically connected to the first through electrodes;

a stress relaxing section including first conductors over the second surface of the semiconductor substrate and electrically connected to the first through electrodes of the semiconductor substrate and having flexibility, the stress relaxing section including a first insulator over the second surface of the semiconductor substrate so as to cover the side surfaces of the first conductors and the second surface of the semiconductor substrate, and having elasticity, the first conductors have columnar shape;

external connecting terminals over the stress relaxing section and connected to the first conductors respectively,

wherein each of the first conductors of the stress relaxing section has a third surface opposite to the second surface of the semiconductor substrate and electrically connected to a corresponding first through electrode, a fourth surface corresponding to a back surface with respect to the third surface and connected to a corresponding external connecting terminal, and a side surface that connects the third surface and the fourth surface, and

wherein the semiconductor substrate, the semiconductor chip and the stress relaxing section are configured together as a semiconductor package; and

conductive films over the second surface of the semiconductor substrate, the conductive films each having a first portion connected to a corresponding first through electrode of the semiconductor substrate and a second portion connected to the third surface of a corresponding first conductor.

12. The semiconductor device according to claim 11 , wherein the first insulator comprises a resin.

13. The semiconductor device according to claim 11 , further including first conductive films over the first surface of the semiconductor substrate, and each having a first portion connected to a corresponding first through electrode of the semiconductor substrate and having a second portion electrically connected to the circuit element of the semiconductor chip.

14. The semiconductor device according to claim 13 , further including encapsulating layers among the semiconductor substrate and the semiconductor chip so as to cover the first conductive films.

15. The semiconductor device according to claim 14 , wherein the encapsulating layers comprise a resin.

16. The semiconductor device according to claim 13 , wherein the semiconductor chip includes second through electrodes, a fifth surface opposite to the first surface of the semiconductor substrate and a sixth surface corresponding to a back surface with respect to the fifth surface, and each of the second through electrodes extend through the fifth surface and the sixth surface and are electrically connected to the circuit element,

the semiconductor device further comprising connecting bumps between the first surface of the semiconductor substrate and the fifth surface of the semiconductor chip, each of said connecting bumps being connected to the second portion of a corresponding first conductive film of the semiconductor substrate and connected to a corresponding second through electrode of the semiconductor chip.

17. The semiconductor device according to claim 11 , further including an encapsulator which covers the semiconductor chip and the first surface of the semiconductor substrate.

18. The semiconductor device according to claim 17 , wherein the encapsulator comprises a resin.

19. The semiconductor device according to claim 17 , wherein the encapsulator contains ceramic.