Detector, PET system and X-ray CT system

1. A detector comprising:

a wiring board;

a plurality of semiconductor chips arranged on the wiring board while being two-dimensionally separated from each other; and

first and second bump electrodes arranged between each of the semiconductor chips and the wiring board;

wherein each of the semiconductor chips comprises:

a semiconductor substrate having a plurality of photodetector units arranged two-dimensionally;

a first insulating layer formed on a front face of the semiconductor substrate;

a common electrode arranged on the first insulating layer and arranged so as to be surrounded on all sides by the photodetector units;

a readout line for electrically connecting a quenching resistor of each of the photodetector units and the common electrode to each other;

a through electrode extending from the common electrode to a rear face of the semiconductor substrate through a through hole of the semiconductor substrate, the through hole tapering toward the common electrode; and

a second insulating layer arranged between an inner surface of the through hole and the through electrode;

wherein sheets are bonded to the semiconductor chips, respectively;

wherein the respective sheets are separate from each other;

wherein each of the photodetector units comprises:

an APD having a first semiconductor region of a first conduction type and a second semiconductor region of a second conduction type for constructing a p-n junction with the first semiconductor region and outputting a carrier; and

the quenching resistor electrically connected to the second semiconductor region of the APD;

wherein the first bump electrode electrically connects the through electrode and the wiring board to each other;

wherein the second bump electrode electrically connects the first semiconductor region of the APD and the wiring board to each other; and

wherein a size of the common electrode is more than two times a size of each of the APDs of the photodetector units.

2. A detector according to claim 1 , wherein a scintillator is disposed on a front face of each of the semiconductor chips with an insulator interposed therebetween.

3. A detector according to claim 1 , wherein each of the photodetector units comprises a surface electrode electrically connected to the second semiconductor region, the surface electrode surrounding the second semiconductor region along an outer edge thereof.

4. A detector according to claim 3 , wherein, letting a plane including the front face of the second semiconductor region be a reference plane, the distance from the reference plane to the readout line is longer than that from the reference plane to the surface electrode; and

wherein the readout line is located between the APDs adjacent to each other.

5. A detector according to claim 1 , comprising:

a first contact electrode in contact with the second semiconductor region; and

a second contact electrode, arranged at such a position as to overlap the first contact electrode while in contact with the first contact electrode, including a material different from that of the first contact electrode;

wherein the quenching resistor is continuous with the second contact electrode.

6. A detector according to claim 5 , wherein the second contact electrode and quenching resistor comprise SiCr.

7. A detector according to claim 1 , wherein the common electrode is placed at the center part of the semiconductor chip.

8. A detector according to claim 1 , wherein the semiconductor comprises:

another common electrode arranged on the first insulating layer; and

another through electrode extending from the another common electrode to a rear face of the semiconductor substrate through a through hole of the semiconductor substrate.

9. A detector according to claim 1 ,

wherein the sheet is comprised of a material that can pass fluorescence from a scintillator.

10. A detector according to claim 9 ,

wherein the sheet is comprised of a material that can diffuse fluorescence from the scintillator.

11. A detector according to claim 9 ,

wherein the sheet is comprised of a glass.

12. A detector according to claim 1 ,

wherein the quenching resistor is electrically connected in series to the second semiconductor region of the APD.

13. A detector according to claim 1 ,

wherein the respective APDs of the photodetector units are electrically connected in parallel.

14. A detector according to claim 1 ,

wherein the semiconductor substrate comprises Si.

15. A detector according to claim 1 ,

wherein the size of the common electrode is more than three times the size of each of the APDs of the photodetector units.

16. A detector according to claim 1 ,

wherein the size of the common electrode is more than four times the size of each of the APDs of the photodetector units.

17. A detector according to claim 1 ,

wherein the first bump electrode is arranged outside the through hole of the semiconductor substrate.

18. A detector according to claim 1 ,

wherein the semiconductor chips are arranged on the wiring board so that a first distance (d 1 ) separates each semiconductor chip from adjacent semiconductor chips,

wherein the respective second semiconductor regions in adjacent semiconductor chips are separated from each other by a second distance (d 2 ), and

wherein the first distance (d 1 ) and the second distance (d 2 ) satisfy the following expression: d 1 +100 μm≤d 2 ≤d 1 +200 μm.

19. A PET system comprising:

a cradle; and

a gantry having an opening for placing the cradle;

wherein a plurality of the detectors according to claim 1 are arranged so as to surround the opening of the gantry.

20. An X-ray CT system comprising:

a cradle; and

a gantry having an opening for placing the cradle and incorporating an X-ray source for emitting an X-ray within the opening;

wherein a plurality of the detectors according to claim 1 are arranged at positions where the X-ray from the X-ray source is incident.

21. A detector according to claim 20 ,

wherein the respective APDs of the photodetector units are electrically connected in parallel.

22. A detector comprising:

a wiring board;

a plurality of semiconductor chips arranged on the wiring board while being two-dimensionally separated from each other; and

first and second bump electrodes arranged between each of the semiconductor chips and the wiring board;

wherein each of the semiconductor chips comprises:

a semiconductor substrate having a plurality of photodetector units arranged two-dimensionally;

a first insulating layer formed on a front face of the semiconductor substrate;

a common electrode arranged on the first insulating layer and arranged so as to be sandwiched by the photodetector units;

a readout line for electrically connecting a quenching resistor of each of the photodetector units and the common electrode to each other;

a through electrode extending from the common electrode to a rear face of the semiconductor substrate through a through hole of the semiconductor substrate, the through hole tapering toward the common electrode; and

a second insulating layer arranged between an inner surface of the through hole and the through electrode;

wherein sheets are bonded to the semiconductor chips, respectively;

wherein the respective sheets are separate from each other;

wherein each of the photodetector units comprises:

an APD having a first semiconductor region of a first conduction type and a second semiconductor region of a second conduction type for constructing a p-n junction with the first semiconductor region and outputting a carrier; and

the quenching resistor electrically connected to the second semiconductor region of the APD;

wherein the first bump electrode electrically connects the through electrode and the wiring board to each other;

wherein the second bump electrode electrically connects the first semiconductor region of the APD and the wiring board to each other; and

wherein a size of the common electrode is more than two times a size of each of the APDs of the photodetector units.

23. A detector according to claim 22 ,

wherein the semiconductor substrate comprises Si.

24. A detector according to claim 22 ,

wherein the size of the common electrode is more than three times the size of each of the APDs of the photodetector units.

25. A detector according to claim 22 ,

wherein the size of the common electrode is more than four times the size of each of the APDs of the photodetector units.

26. A detector according to claim 22 ,

wherein the first bump electrode is arranged outside the through hole of the semiconductor substrate.

27. A detector according to claim 22 ,

wherein the semiconductor chips are arranged on the wiring board so that a first distance (d 1 ) separates each semiconductor chip from adjacent semiconductor chips,

wherein the respective second semiconductor regions in adjacent semiconductor chips are separated from each other by a second distance (d 2 ), and

wherein the first distance (d 1 ) and the second distance (d 2 ) satisfy the following expression: d 1 +100 μm≤d 2 ≤d 1 +200 μm.

28. A detector comprising:

a wiring board;

semiconductor chips arranged on the wiring board, each of the semiconductor chips comprising:

a semiconductor substrate comprising APDs, each of the APDs including a p-n junction constructed by a first semiconductor region of a first conduction type and a second semiconductor region of a second conduction type;

quenching resistors electrically connected to the APDs, respectively;

a first insulating layer arranged on a front face of the semiconductor substrate;

a first electrode arranged on the first insulating layer, connected to the APDs, and arranged so as to be sandwiched by the APDs;

a second electrode extending from the first electrode to a rear face of the semiconductor substrate through a through hole of the semiconductor substrate, the through hole tapering toward the first electrode; and

a second insulating layer arranged between an inner surface of the through hole and the second electrode;

bump electrodes arranged between each of the semiconductor chips and the wiring board, the second electrode and the APDs being electrically connected to the wiring board via the bump electrodes; and

sheets bonded to the semiconductor chips, respectively,

wherein a size of the first electrode is more than two times a size of each of the APDs.

29. A detector according to claim 28 ,

wherein the semiconductor substrate comprises Si.

30. A detector according to claim 28 ,

wherein the size of the first electrode is more than three times the size of each of the APDs.

31. A detector according to claim 28 ,

wherein the size of the first electrode is more than four times the size of each of the APDs.

32. A detector according to claim 28 ,

wherein the bump electrodes are arranged outside the through hole of the semiconductor substrate.

33. A detector according to claim 28 ,

wherein the semiconductor chips are arranged on the wiring board so that a first distance (d 1 ) separates each semiconductor chip from adjacent semiconductor chips,

wherein the respective second semiconductor regions in adjacent semiconductor chips are separated from each other by a second distance (d 2 ), and

wherein the first distance (d 1 ) and the second distance (d 2 ) satisfy the following expression: d 1 +100 μm≤d 2 ≤d 1 +200 μm.