Backside illumination solid-state imaging device

• US 8,378,399 B2
• Filed: 07/13/2011
• Issued: 02/19/2013
• Est. Priority Date: 07/14/2010
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Maeda, Motohiro
• Primary Examiner(s): NGO, NGAN V
• Application Number:
  US13/181,711
• Publication Number:
  US 20120012965A1
• Time in Patent Office: 587 Days
• Field of Search: 257/291, 257/292, 257/294, 257/435, 257/447, 257/448, 257/E31.121, 257/E31.122
• US Class Current: 257/292
• CPC Class Codes: H01L 27/14623 Optical shielding
• CPC Class Codes: H01L 27/1463 Pixel isolation structures
• CPC Class Codes: H01L 27/1464 Back illuminated imager structures
• CPC Class Codes: H04N 25/778 comprising amplifiers shared between a plurality of pixels, i.e. at least one part of the amplifier must be on the sensor array itself

Abstract

According to one embodiment, a backside illumination solid-state imaging device includes a semiconductor layer, a first light-receiving unit and a second light-receiving unit, a circuit unit, an impurity isolation layer, and a light-shielding film. A first light-receiving unit and a second light-receiving unit are formed adjacent to each other in the semiconductor layer, convert light applied from a lower surface side of the semiconductor layer into a signal, and store electric charges. A circuit unit is formed on an upper surface of the semiconductor layer. An impurity isolation layer is formed to reach to the upper surface from the lower surface in the semiconductor layer and isolates the first light-receiving unit from the second light-receiving unit. A light-shielding film is formed on part of the lower surface side in the impurity isolation layer so as to extend from the lower surface to the upper surface.

Claims

1. A backside illumination solid-state imaging device comprising:

a semiconductor layer;

a first light-receiving unit and a second light-receiving unit which are formed adjacent to each other in the semiconductor layer, convert light applied from a lower surface side of the semiconductor layer into a signal, and store electric charges;

a circuit unit which is formed on an upper surface of the semiconductor layer and reads electric charges stored in the first light-receiving unit and the second light-receiving unit;

an impurity isolation layer which is formed to reach to the upper surface from the lower surface in the semiconductor layer and isolates the first light-receiving unit from the second light-receiving unit; and

a light-shielding film which is formed on part of the lower surface side in the impurity isolation layer so as to extend from the lower surface to the upper surface.

2. The device of claim 1, further comprising an interconnection which is formed on the lower surface of the semiconductor layer to apply one of a ground voltage and a negative bias to the light-shielding film,

wherein the light-shielding film has conductivity.

3. The device of claim 2, wherein the interconnection applies one of a ground voltage and a negative bias from the circuit unit to the light-shielding film via a through-via formed to reach to the upper surface from the lower surface in the semiconductor layer.

4. The device of claim 1, wherein the light-shielding film is formed to reach to the upper surface from the lower surface in the semiconductor layer.

5. The device of claim 1, wherein the semiconductor layer is of an n type, and the impurity isolation layer is of a p type.

6. The device of claim 1, wherein boron is introduced into the impurity isolation layer.

7. The device of claim 1, wherein the light-shielding film includes one of a metal and polysilicon.

8. The device of claim 1, wherein the light-shielding film includes an insulator.

9. The device of claim 1, wherein the light-shielding film has reflectivity.

10. The device of claim 1, wherein the light-shielding film has a width of 0.5 μ

m to 5 μ

m, and the semiconductor layer has a thickness of 1 μ

m to 5 μ

m.

11. The device of claim 4, wherein the light-shielding film has a width of 0.5 μ

m to 5 μ

m, and the semiconductor layer has a thickness of 1 μ

m to 3 μ

m.

12. The device of claim 4, wherein the circuit unit directly applies one of a ground voltage and a negative bias to the light-shielding film.

13. The device of claim 1, wherein a depth of the light-shielding film is not less than 10% of a thickness of the semiconductor layer.

14. A backside illumination solid-state imaging device comprising:

a semiconductor layer;

a first light-receiving unit and a second light-receiving unit which are formed adjacent to each other in the semiconductor layer, convert light applied from a lower surface side of the semiconductor layer into a signal, and store electric charges;

a circuit unit which is formed on an upper surface of the semiconductor layer and reads electric charges stored in the first light-receiving unit and the second light-receiving unit;

a light-shielding film having conductivity which is formed to reach the upper surface from the lower surface in the semiconductor layer and isolates the first light-receiving unit from the second light-receiving unit; and

an interconnection which is formed on the lower surface of the semiconductor layer and applies one of a ground voltage and a negative bias to the light-shielding film.

15. The device of claim 14, wherein the interconnection applies one of a ground voltage and a negative bias from the circuit unit to the light-shielding film via a through-via formed to reach the upper surface from the lower surface in the semiconductor layer.

16. The device of claim 14, wherein the light-shielding film includes one of a metal and polysilicon.

17. The device of claim 14, wherein the light-shielding film has reflectivity.

18. The device of claim 14, wherein the light-shielding film has a width of 0.5 μ

m to 5 μ

m, and the semiconductor layer has a thickness of 1 μ

m to 3 μ

m.

19. The device of claim 14, wherein the circuit unit directly applies one of a ground voltage and a negative bias to the light-shielding film.