# US 10,319,771 B2 · Image sensors and methods of forming the same

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- Number: US 10,319,771 B2
- Document ID: US10319771B2
- Status: Granted
- Kind: B2
- Application number: 15/991,319
- Filed: 2018-05-29
- Published: 2018-09-27
- Granted: 2019-06-11
- Earliest claimed: 2015-01-13
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Samsung Electronics Co., Ltd.
- Inventors: Yun Ki Lee
- Web page: https://patentgrep.com/patent/US10319771B2

## CPC

- H10F 39/807: {Pixel isolation structures}
- H04N 25/633: by using optical black pixels
- H04N 25/673: by using reference sources
- H04N 25/68: applied to defects
- H10F 39/014: {of CMOS image sensors}
- H10F 39/026: {Wafer-level processing}
- H10F 39/18: Complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors
- H10F 39/199: {Back-illuminated image sensors}
- H10F 39/8057: {Optical shielding}
- H10F 39/8053: {Colour filters}
- H10F 39/8063: {Microlenses}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An image sensor includes a substrate including a light-receiving region and a light-shielding region, a device isolation pattern in the substrate of the light-receiving region to define active pixels, and a device isolation region in the substrate of the light-shielding region to define reference pixels. An isolation technique of the device isolation pattern is different from that of the device isolation region.

## Claims

### Claim 1

An image sensor comprising:
a substrate having a first surface and a second surface opposite to the first surface;
a plurality of photoelectric conversion parts between the first and second surfaces;
a plurality of interconnection structures on the first surface;
a light shielding pattern on the second surface of the substrate;
a first trench recessed from the second surface of the substrate overlapping the light shielding pattern;
a second trench recessed from the second surface of the substrate and not overlapping the light shielding pattern;
a first device isolation pattern in the first trench; and
a second device isolation pattern in the second trench,
wherein a length of the second device isolation pattern is different from a length of the first device isolation pattern.

### Claim 2 (depends on 1)

The image sensor of claim 1, further comprising a third trench between the first trench and the second trench, the third trench having a substantially same height with the second trench, and the third trench being positioned at or near a first end of the light shielding pattern.

### Claim 3 (depends on 1)

The image sensor of claim 1, further comprising a p-type doping region under the first surface of the substrate.

### Claim 4 (depends on 3)

The image sensor of claim 3, wherein the second trench contacts the p-type doping region.

### Claim 5 (depends on 1)

The image sensor of claim 1, further comprising an anti-reflection layer between the light shielding pattern and the second surface of the substrate.

### Claim 6 (depends on 1)

The image sensor of claim 1, the first and second device isolation patterns comprise insulating material.

### Claim 7 (depends on 6)

The image sensor of claim 6, wherein the insulating material has a refractive index lower than a refractive index of the substrate.

### Claim 8 (depends on 1)

The image sensor of claim 1, wherein the first trench is in a light shielding region, the second trench is formed in a light receiving region, and a third trench is formed in a dummy region, wherein each first, second, and third trench is between the plurality of photoelectric conversion parts.

### Claim 9 (depends on 1)

The image sensor of claim 1, wherein:
the light shielding pattern extends on more than one of the plurality of photoelectric conversion parts; and
the second trench does not overlap a light shielding material.

### Claim 10

An image sensor comprising:
a substrate having a first surface and a second surface opposite to the first surface;
a plurality of photoelectric conversion parts between the first and second surfaces;
a plurality of interconnection structures on the first surface;
a light shielding pattern on the second surface of the substrate;
a first trench recessed from the second surface of the substrate overlapping the light shielding pattern;
a second trench recessed from the second surface of the substrate and not overlapping the light shielding pattern;
a first device isolation pattern in the first trench; and
a second device isolation pattern in the second trench,
wherein the light shielding pattern overlaps at least one of the photoelectric conversion parts in a plan view, and
wherein a bottom surface of the light shielding pattern is at a same or higher level than the second surface of the substrate.

### Claim 11 (depends on 1)

The image sensor of claim 1, wherein the first device isolation pattern is between at least two of the photoelectric conversion parts.

### Claim 12 (depends on 1)

The image sensor of claim 1, wherein the first device isolation pattern is configured to define reference pixels, and
wherein the second device isolation pattern is configured to define active pixels.