Solid-state image sensor

Patent metadata

Field	Value
Publication number	US-9478575-B2
Application number	US-201214233329-A
Country	US
Kind code	B2
Filing date	Aug 21, 2012
Priority date	Sep 1, 2011
Publication date	Oct 25, 2016
Grant date	Oct 25, 2016

Abstract

An image sensor includes a first pixel having a first color filter, a first reflection region which reflects light from the first color filter, and a first photoelectric conversion portion arranged in a semiconductor layer and located between the first color filter and the first reflection region, and a second pixel including a second color filter, a second reflection region which reflects light from the second color filter, and a second photoelectric conversion portion arranged in the semiconductor layer and located between the second color filter and the second reflection region. Wavelength corresponding to a maximum transmittance of the first color filter is shorter than wavelength corresponding to a maximum transmittance of the second color filter. An area of the first reflection region is smaller than area of the second reflection region.

First claim

The invention claimed is:

1. A solid-state image sensor including a semiconductor layer and a wiring structure, wherein the semiconductor layer is a silicon substrate having a thickness not less than 2 μm, the sensor comprising:
a pixel of a first type including a first color filter, a first member included in one wiring layer of the wiring structure, and a first photoelectric conversion portion arranged in the semiconductor layer, the first photoelectric conversion portion being located between the first color filter and the first member; and
a pixel of a second type including a second color filter, a second member included in one wiring layer of the wiring structure, the second member having a reflection region which reflects light transmitted through the semiconductor layer, and a second photoelectric conversion portion arranged in the semiconductor layer, the second photoelectric conversion portion being located between the second color filter and the second member,
wherein the semiconductor layer has a first face and a second face, the first member and the second member are arranged on a side of the first face, the first color filter and the second color filter are arranged on a side of the second face,
wherein the wiring structure includes an insulation film disposed between the one wiring layer and the semiconductor layer, and an electrode of polysilicon is arranged between the insulation film and the semiconductor layer,
wherein a wavelength corresponding to a maximum transmittance of the first color filter is in a blue wavelength range and is shorter than a wavelength corresponding to a maximum transmittance of the second color filter,
wherein an area of the first member projected onto the first face of the semiconductor layer is smaller than an area of the second member projected onto the first face, and
wherein the electrode and the first member are both arranged on a single axis perpendicular to the first face.

2. The sensor according to claim 1 , wherein the pixel of the first type further includes a first transistor configured to read out a signal of the first photoelectric conversion portion,
wherein the pixel of the second type further includes a second transistor to read out a signal of the second photoelectric conversion portion, and
wherein the electrode is a gate electrode of the first transistor.

3. The sensor according to claim 1 , wherein a gate electrode of the second transistor and the second member are both arranged on a single axis perpendicular to the first face.

4. The sensor according to claim 1 , wherein the first member is positioned between the electrode and another wiring layer of the wiring structure in a direction perpendicular to the first face.

5. The sensor according to claim 1 , wherein the one wiring layer including the first member and the second member is arranged between the semiconductor layer and a plurality of wiring layers of the wiring structure.

6. The sensor according to claim 1 , further comprising:
a pixel of a third type including a third color filter, third member included in one wiring layer of the wiring structure, and a third photoelectric conversion portion arranged in the semiconductor layer, the third photoelectric conversion portion being located between the third color filter and the third member,
wherein the wavelength corresponding to the maximum transmittance of the second color filter is shorter than a wavelength corresponding to a maximum transmittance of the third color filter, and
wherein the area of the second member projected onto the first face is not smaller than an area of the third member projected onto the first face.

7. The sensor according to claim 1 , wherein the first member and the second member contain one of aluminum, copper, gold, tungsten, titanium, and tantalum as a major component.

8. The sensor according to claim 1 , wherein 99.0% or more of light rays which are transmitted through the first color filter is absorbed by the semiconductor layer before the light rays reach the first face.

9. The sensor according to claim 1 , wherein an insulator is arranged between the first photoelectric conversion portion and the second photoelectric conversion portion.

10. The sensor according to claim 1 , wherein the pixel of the first type further includes a first microlens arranged on the side of the second face,
wherein the pixel of the second type further includes a second microlens arranged on the side of the second face, and
wherein a focus position of the second microlens being set between the first face and the reflection region of the second member.

11. The sensor according to claim 1 , wherein the wavelength corresponding to the maximum transmittance of the second color filter is in a green wavelength range.

12. The sensor according to claim 6 , the area of the first member projected onto the first face is smaller than an area of the third member projected onto the first face.

13. The sensor according to claim 1 , wherein the reflection region of the second member has a concave surface.

14. The sensor according to claim 1 , wherein the first member and the second member applied with a fixed potential.

15. The sensor according to claim 1 , wherein an entire area of the first member projected onto the first face is included in an area of the electrode projected onto the first face.

Assignees

• Kato Taro
• Canon Kk

Inventors

• Kato Taro

Classifications

• H10F39/8067

  Reflectors · CPC title

• H10F39/8053 Primary

  Colour filters · CPC title

• H10F39/806 Primary

  Optical elements or arrangements associated with the image sensors · CPC title

• H01L27/14621

  Electricity · mapped topic

• H01L27/14625 Primary

  Electricity · mapped topic