Semiconductor device, stacked semiconductor device, methods of manufacturing them, circuit board, and electronic instrument

1. A semiconductor device comprising:

a semiconductor substrate having an integrated circuit and a penetrating hole;

an insulating layer formed on an inner surface of the penetrating hole; and

a conductive section formed on the insulating layer to penetrate the semiconductor substrate and having a recess on an end surface,

wherein the recess has an internal space the width of which is larger than the width of an opening of the recess; and

wherein the recess is formed not to penetrate entirely through the conductive section.

2. The semiconductor device as defined in claim 1 , wherein:

a pad electrically connected to the integrated circuit is formed on a first surface of the semiconductor substrate; and

the end surface is exposed from a second surface of the semiconductor substrate opposite to the first surface.

3. The semiconductor device as defined in claim 1 ,

wherein the end surface is an uneven surface including a plurality of the recesses.

4. The semiconductor device as defined in claim 3 ,

wherein the end surface is more uneven than the other end surface of the conductive section.

5. The semiconductor device as defined in claim 1 , wherein: an end portion of the conductive section having the end surface including the recess projects from the semiconductor substrate; and

the recess has such a depth that a bottom of the recess is positioned inside the semiconductor substrate.

6. A stacked semiconductor device comprising:

a plurality of the semiconductor devices as defined in claim 1 which are stacked,

wherein electrical connection of the semiconductor devices are achieved through the conductive sections.

7. The stacked semiconductor device as defined in claim 6 , further comprising:

a conductive material which partially enters the recesses to connect the conductive sections of vertically adjacent semiconductor devices among the semiconductor devices.

8. A circuit board on which is mounted the semiconductor device as defined in claim 1 .

9. An electronic instrument comprising the semiconductor device as defined in claim 1 .

10. A method of manufacturing a semiconductor device, comprising:

(a) forming a penetrating hole in a semiconductor substrate which has an integrated circuit;

(b) forming an insulating layer on an inner surface of the penetrating hole;

(c) forming a conductive section on the insulating layer to penetrate the semiconductor substrate; and

(d) forming a recess on an end surface of the conductive sections,

wherein the recess has an internal space the width of which is larger than the width of an opening of the recess; and

wherein the recess is formed not to penetrate entirely through the conductive section.

11. The method of manufacturing a semiconductor device as defined in claim 10 , wherein:

the hole is formed so as not to penetrate the semiconductor substrate in the step (a); and

the end surface is exposed from the semiconductor substrate after the step (c).

12. The method of manufacturing a semiconductor device as defined in claim 10 , wherein:

a pad electrically connected to the integrated circuit is formed on a first surface of the semiconductor substrate; and

the end surface is exposed from a second surface of the semiconductor substrate opposite to the first surface.

13. The method of manufacturing a semiconductor device as defined in claim 10 , wherein:

the conductive section is formed to have a void in the step (c); and

the recess is formed by removing part of the end surface of the conductive section and opening the void in the step (d).

14. The method of manufacturing a semiconductor device as defined in claim 10 ,

wherein the recess is formed to have an internal space the width of which is larger than the width of an opening of the recess in the step (d).

15. The method of manufacturing a semiconductor device as defined in claim 10 ,

wherein the end surface is made uneven to have a plurality of the recesses in the step (d).

16. The method of manufacturing a semiconductor device as defined in claim 15 ,

wherein the end surface is made more uneven than the other end surface of the conductive section in the step (d).

17. The method of manufacturing a semiconductor device as defined in claim 10 , wherein:

an end portion of the conductive section having the end surface including the recess projects from the semiconductor substrate; and

the recess is formed to have such a depth that a bottom of the recess is positioned inside the semiconductor substrate in the step (d).

18. The method of manufacturing a semiconductor device as defined in claim 10 ,

wherein the step (d) includes removing part of the end surface by etching.

19. The method of manufacturing a semiconductor device as defined in claim 10 , wherein:

the semiconductor substrate is a semiconductor wafer including a plurality of integrated circuits;

the hole is formed for each of the integrated circuits; and the semiconductor substrate is cut after the step (d).

20. A method of manufacturing a stacked semiconductor device, comprising:

stacking a plurality of semiconductor devices each of which includes: a semiconductor substrate having an integrated circuit and a penetrating hole; an insulating layer formed on an inner surface of the penetrating hole; and a conductive section formed on the insulating layer to penetrate the semiconductor substrate and having a recess on an end surface; and

achieving electrical connection of the semiconductor devices through the conductive sections;

wherein the recess is formed not to penetrate entirely through the conductive section; and

wherein the recess has an internal space the width of which is larger than the width of an opening of the recess.

21. The method of manufacturing a stacked semiconductor device as defined in claim 20 ,

wherein a conductive material partially enters the recesses to connect the conductive sections of vertically adjacent semiconductor devices among the semiconductor devices.