Semiconductor device and method of manufacturing semiconductor device

1. A semiconductor device comprising:

a first chip and a second chip, the first chip and the second chip being stacked on top of each other, the first chip having a first area, in which a plurality of first cells are arranged in matrix, the second chip having a second area, in which an electric circuit is arranged,

wherein a plurality of wiring lines electrically connects the first chip and the second chip, each of the plurality of wiring lines includes a bonding portion for bonding one of a plurality of conductive patterns placed in the first chip and one of a plurality of conductive patterns placed in the second chip,

wherein the plurality of first cells each includes a photoelectric converter, a charge detector which detects an electric charge of the photoelectric converter, a transfer gate which transfers an electric charge of the photoelectric converter to the charge detector, and a reset transistor which resets an electric potential of the charge detector,

wherein the number of bonding portions included in a first wiring line out of the plurality of wiring lines is larger than the number of bonding portions included in a second wiring line out of the plurality of wiring lines,

wherein at least one of the bonding portions included in the first wiring line and the bonding portions included in the second wiring line is arranged in an overlap area, in which the first area and the second area overlap, and

wherein the first wiring line is connected to one of a source and a drain of the reset transistor.

2. The semiconductor device according to claim 1 , wherein a ratio of a number of transistors of the first chip connected to the first wiring line to the number of bonding portions included in the first wiring line is higher than a ratio of the number of transistors of the second chip connected to the second wiring line to the number of bonding portions included in the second wiring line.

3. The semiconductor device according to claim 1 , wherein a ratio of the number of contacts between the first wiring line and a semiconductor layer of the first chip to the number of bonding portions included in the first wiring line is different from a ratio of the number of contacts between the second wiring line and a semiconductor layer of the second chip to the number of bonding portions included in the second wiring line.

4. The semiconductor device according to claim 1 ,

wherein the electric circuit includes a part of a comparator, which includes a differential pair, and

wherein the detection transistor is one of transistors of the differential pair.

5. The semiconductor device according to claim 4 , wherein the plurality of first cells each includes another transistor out of the transistors of the differential pair.

6. The semiconductor device according to claim 5 ,

wherein the another transistor is connected to a third wiring line, which is one of the plurality of wiring lines in the overlap area, and

wherein the number of bonding portions included in the third wiring line is larger than the number of bonding portions included in the second wiring line.

7. The semiconductor device according to claim 6 , further comprising:

a fourth wiring line provided around the overlap area, and

wherein the number of bonding portions included in the fourth wiring line is larger than the number of bonding portions included in the second wiring line.

8. The semiconductor device according to claim 7 , wherein a ratio of the number of contacts between the fourth wiring line and a semiconductor layer of the first chip to the number of bonding portions included in the fourth wiring line is higher than a ratio of the number of contacts between the second wiring line and a semiconductor layer of the second chip to the number of bonding portions included in the second wiring line.

9. The semiconductor device according to claim 8 ,

wherein the semiconductor layer of the first chip has an opening formed therein,

wherein one of the first chip and the second chip includes an electrode positioned below the opening, and

wherein the fourth wiring line is connected to the electrode.

10. The semiconductor device according to claim 1 , further comprising:

a third chip, the third chip having a third area, in which a plurality of third cells are arranged in matrix,

wherein the first chip, the second chip, and the third chip are stacked so as to sandwich the second chip between the third chip and the first chip, wherein the second area and the third area overlap in the overlap area, and a semiconductor layer of the second chip in the overlap area is provided with a plurality of through-electrodes electrically connect the second chip and the third chip, and

wherein at least two third cells out of the plurality of third cells provided in the third chip are connected to one through-electrode out of the plurality of through-electrodes.

11. The semiconductor device according to claim 1 , wherein the bonding portions included in the first wiring line and the bonding portions included in the second wiring line are arranged in the overlap area.

12. The semiconductor device according to claim 11 ,

wherein a plurality of second cells are arranged in matrix within the second area, and

wherein each of the plurality of second cells includes the electric circuit.

13. The semiconductor device according to claim 1 ,

wherein the one of the plurality of conductive patterns placed in the first chip forms a part of the top of the first chip, and

wherein the one of the plurality of conductive patterns placed in the second chip forms a part of the top of the second chip.

14. The semiconductor device according to claim 1 , wherein each of the plurality of wiring lines includes the one of the plurality of conductive patterns placed in the first chip and the one of the plurality of conductive patterns placed in the second chip.

15. An image pickup system comprising:

the semiconductor device according to claim 1 ; and

a circuit board.

16. The image pickup system according to claim 15 , wherein the image pickup system is a smartphone, a wearable terminal, or a transportation equipment.

17. The image pickup system according to claim 15 , further comprising:

a display unit for displaying image information obtained from the semiconductor device.

18. The semiconductor device according to claim 1 , wherein the first wiring line is shared by two or more first cells out of the plurality of first cells.

19. A semiconductor device comprising:

a first chip and a second chip, the first chip and the second chip being stacked on top of each other, the first chip having a first area, in which a plurality of first cells are arranged in matrix, the second chip having a second area, in which an electric circuit is arranged,

wherein a plurality of wiring lines electrically connect the first chip and the second chip, each of the plurality of wiring lines includes a bonding portion for bonding one of a plurality of conductive patterns placed in the first chip and one of a plurality of conductive patterns placed in the second chip,

wherein the plurality of first cells each includes a photoelectric converter, a charge detector which detects an electric charge of the photoelectric converter, a transfer gate which transfers an electric charge of the photoelectric converter to the charge detector, and a reset transistor which resets an electric potential of the charge detector,

wherein the number of bonding portions included in a first wiring line out of the plurality of wiring lines is larger than the number of bonding portions included in a second wiring line out of the plurality of wiring lines,

wherein at least one of the bonding portions included in the first wiring line and the bonding portions included in the second wiring line is arranged in an overlap area, in which the first area and the second area overlap, and

wherein the second wiring line is connected to one of a source and a drain of the reset transistor.

20. The semiconductor device according to claim 19 , wherein a ratio of a number of transistors of the first chip connected to the first wiring line to the number of bonding portions included in the first wiring line is different from a ratio of the number of transistors of the second chip connected to the second wiring line to the number of bonding portions included in the second wiring line.

21. The semiconductor device according to claim 19 , wherein a ratio of the number of contacts between a first wiring line, which is one of the plurality of wiring lines, and a semiconductor layer of the first chip to the number of bonding portions included in the first wiring line is higher than a ratio of the number of contacts between a second wiring line, which is one of the plurality of wiring lines, and a semiconductor layer of the second chip to the number of bonding portions included in the second wiring line.

22. An image pickup system comprising:

the semiconductor device according to claim 19 ; and

a circuit board.

23. The image pickup system according to claim 22 , wherein the image pickup system is a smartphone, a wearable terminal, or a transportation equipment.

24. The image pickup system according to claim 22 , further comprising:

a display unit for displaying image information obtained from the semiconductor device.

25. A semiconductor device comprising:

a first chip and a second chip, the first chip and the second chip being stacked on top of each other, the first chip having a first area, in which a plurality of first cells are arranged in matrix, the second chip having a second area, in which an electric circuit is arranged,

wherein a plurality of wiring lines electrically connect the first chip and the second chip, each of the plurality of wiring lines includes a bonding portion for bonding one of a plurality of conductive patterns placed in the first chip and one of a plurality of conductive patterns placed in the second chip,

wherein the plurality of first cells each includes a photoelectric converter, a charge detector which detects an electric charge of the photoelectric converter, a transfer gate which transfers an electric charge of the photoelectric converter to the charge detector, and a discharge transistor which discharges the electric charge of the photoelectric converter,

wherein the number of bonding portions included in a first wiring line out of the plurality of wiring lines is larger than the number of bonding portions included in a second wiring line out of the plurality of wiring lines,

wherein at least one of the bonding portions included in the first wiring line and the bonding portions included in the second wiring line is arranged in an overlap area, in which the first area and the second area overlap, and

wherein the first wiring line is connected to one of a source and a drain of the discharge transistor.

26. The semiconductor device according to claim 25 , wherein a ratio of a number of transistors of the first chip connected to the first wiring line to the number of bonding portions included in the first wiring line is different from a ratio of the number of transistors of the second chip connected to the second wiring line to the number of bonding portions included in the second wiring line.

27. The semiconductor device according to claim 25 , wherein a ratio of the number of contacts between a first wiring line, which is one of the plurality of wiring lines, and a semiconductor layer of the first chip to the number of bonding portions included in the first wiring line is higher than a ratio of the number of contacts between a second wiring line, which is one of the plurality of wiring lines, and a semiconductor layer of the second chip to the number of bonding portions included in the second wiring line.

28. An image pickup system comprising:

the semiconductor device according to claim 25 ; and

a circuit board.

29. The image pickup system according to claim 28 , wherein the image pickup system is a smartphone, a wearable terminal, or a transportation equipment.

30. The image pickup system according to claim 28 , further comprising:

a display unit for displaying image information obtained from the semiconductor device.