Solid-state image sensor

Patent metadata

Field	Value
Publication number	US-12446344-B2
Application number	US-202117794865-A
Country	US
Kind code	B2
Filing date	Jan 18, 2021
Priority date	Jan 31, 2020
Publication date	Oct 14, 2025
Grant date	Oct 14, 2025

Abstract

A solid-state image sensor according to the present disclosure includes a photodiode, a conversion circuit (current-voltage conversion circuit), a luminance change detection circuit (comparator), and a light-shielding unit (light-shielding film). The photodiode photoelectrically converts incident light to generate a photocurrent. The conversion circuit (current-voltage conversion circuit) converts the photocurrent into a voltage signal. The luminance change detection circuit (comparator) detects a change in luminance of the incident light on the basis of the voltage signal. The light-shielding unit (light-shielding film) shields incidence of light on the impurity diffusion region included in a circuit that inputs the voltage signal to the luminance change detection circuit (comparator).

First claim

What is claimed is:

1. A solid-state image sensor, comprising:
a photodiode configured to photoelectrically convert incident light to generate a photocurrent;
a conversion circuit configured to convert the photocurrent into a voltage signal;
a luminance change detection circuit configured to detect a change in luminance of the incident light on a basis of the voltage signal; and
a light-shielding unit configured to shield incidence of light on an impurity diffusion region included in a circuit that inputs the voltage signal to the luminance change detection circuit.

2. The solid-state image sensor according to claim 1 , wherein
the light-shielding unit
is a light-shielding film that covers a wiring layer stacked on a semiconductor layer including the photodiode.

3. The solid-state image sensor according to claim 1 , wherein
the light-shielding unit
is a light-shielding film that covers a light-incident-side surface of a semiconductor layer including the photodiode.

4. The solid-state image sensor according to claim 2 , wherein
the light-shielding film
is provided at a position overlapping with the impurity diffusion region, includes the impurity diffusion region in plan view, and has a protrusion width from an outer periphery of the impurity diffusion region in side view, the protrusion width being equal to or larger than a distance to the impurity diffusion region in side view.

5. The solid-state image sensor according to claim 1 , wherein
the light-shielding unit
is wiring provided for a purpose of shielding light in a wiring layer provided close to a side where the incident light is incident, with respect to the impurity diffusion region.

6. The solid-state image sensor according to claim 5 , wherein
the wiring provided for the purpose of shielding light
is provided at a position overlapping with the impurity diffusion region, includes the impurity diffusion region in plan view, and has a protrusion width from an outer periphery of the impurity diffusion region in side view, the protrusion width being equal to or larger than a distance to the impurity diffusion region in side view.

7. The solid-state image sensor according to claim 5 , wherein
the wiring provided for the purpose of shielding light
includes a plurality of layers of wiring at least partially overlapping in plan view.

8. The solid-state image sensor according to claim 1 , wherein
the light-shielding unit
includes a light-shielding member embedded in a trench provided between an active element that emits light by hot carriers and the impurity diffusion region.

9. The solid-state image sensor according to claim 1 , wherein
the impurity diffusion region
is provided outside a region through which a light beam of the incident light condensed on the photodiode by a lens passes and is connected to a capacitive element included in a circuit that inputs the voltage signal to the luminance change detection circuit.

10. A solid-state image sensor, comprising:
a photodiode configured to photoelectrically convert incident light to generate a photocurrent;
a conversion circuit configured to convert the photocurrent into a voltage signal;
a luminance change detection circuit configured to detect a change in luminance of the incident light on a basis of the voltage signal;
an impurity diffusion region provided outside a region through which a light beam of the incident light condensed on the photodiode by a lens passes, and included in a circuit that inputs the voltage signal to the luminance change detection circuit; and
a light-shielding unit configured to shield incidence of light on the impurity diffusion region.

11. The solid-state image sensor according to claim 10 , wherein
the light-shielding unit
is a light-shielding film that covers a wiring layer stacked on a semiconductor layer including the photodiode.

12. The solid-state image sensor according to claim 10 , wherein
the light-shielding unit
is a light-shielding film that covers a light-incident-side surface of a semiconductor layer including the photodiode.

13. The solid-state image sensor according to claim 11 , wherein
the light-shielding film
is provided at a position overlapping with the impurity diffusion region, includes the impurity diffusion region in plan view, and has a protrusion width from an outer periphery of the impurity diffusion region in side view, the protrusion width being equal to or larger than a distance to the impurity diffusion region in side view.

14. The solid-state image sensor according to claim 10 , wherein
the light-shielding unit
is wiring provided for a purpose of shielding light in a wiring layer provided close to a side where the incident light is incident, with respect to the impurity diffusion region.

15. The solid-state image sensor according to claim 14 , wherein
the wiring provided for the purpose of shielding light
is provided at a position overlapping with the impurity diffusion region, includes the impurity diffusion region in plan view, and has a protrusion width from an outer periphery of the impurity diffusion region in side view, the protrusion width being equal to or larger than a distance to the impurity diffusion region in side view.

16. The solid-state image sensor according to claim 14 , wherein
the wiring provided for the purpose of shielding light
includes a plurality of layers of wiring at least partially overlapping in plan view.

17. The solid-state image sensor according to claim 10 , wherein
the light-shielding unit
includes a light-shielding member filled in a trench provided between an active element that emits light by hot carriers and the impurity diffusion region.

18. The solid-state image sensor according to claim 1 , wherein
the impurity diffusion region
is connected to a capacitive element included in a circuit that inputs the voltage signal to the luminance change detection circuit.

19. The solid-state image sensor according to claim 1 , wherein
the impurity diffusion region
is connected to a gate of a reset transistor that discharges and resets a capacitive element included in a circuit that inputs the voltage signal to the luminance change detection circuit.

Assignees

• Sony Semiconductor Solutions Corp

Inventors

• Tsuchimoto Koya
• Kitano Shin
• Murakawa Yusuke
• Nakamura Makoto
• Hanada Takuya
• Noda Yuki

Classifications

• H10F39/811

  Interconnections · CPC title

• H10F39/809

  of hybrid image sensors · CPC title

• H10F39/18

  Complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors · CPC title

• H10F39/807

  Pixel isolation structures · CPC title

• H10F39/8063

  Microlenses · CPC title