# US 11,908,878 B2 · Image sensor and manufacturing method thereof

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- Number: US 11,908,878 B2
- Document ID: US11908878B2
- Status: Granted
- Kind: B2
- Application number: 17/327,996
- Filed: 2021-05-24
- Published: 2022-07-21
- Granted: 2024-02-20
- Earliest claimed: 2021-01-15
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Co., Ltd.
- Inventors: Min-Feng Kao; Dun-Nian Yaung; Jen-Cheng Liu; Wen-Chang Kuo; Sheng-Chau Chen; Feng-Chi Hung; Sheng-Chan Li
- Web page: https://patentgrep.com/patent/US11908878B2

## CPC

- H10F 39/807: {Pixel isolation structures}
- H10F 39/024: {of coatings or optical elements}
- H10F 39/199: {Back-illuminated image sensors}
- H10F 39/8057: {Optical shielding}
- H10F 39/811: {Interconnections}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

An image sensor includes a pixel and an isolation structure. The pixel includes a photosensitive region and a circuitry region next to the photosensitive region. The isolation structure is located over the pixel, where the isolation structure includes a conductive grid and a dielectric structure covering a sidewall of the conductive grid, and the isolation structure includes an opening or recess overlapping the photosensitive region. The isolation structure surrounds a peripheral region of the photosensitive region.

## Claims

### Claim 1

An image sensor, comprising:
a substrate, having an active region and a peripheral region next to the active region;
a pixel arranged in the active region and comprising a photosensitive region and a circuitry region next to the photosensitive region;
an isolation structure disposed in the substrate at a first side of the substrate surrounding the photosensitive region, wherein the isolation structure comprises a conductive grid and a dielectric structure covering a sidewall of the conductive grid;
a conductive structure disposed in the substrate within the peripheral region, wherein the conductive grid is electrically connected to the conductive structure; and
an isolation disposed in the substrate under the conductive structure at a second side opposite to the first side of the substrate,
wherein the conductive structure is in contact with the isolation and electrically connecting the conductive grid and a conductive component at the first side of the substrate through the isolations.

### Claim 2 (depends on 1)

The image sensor of claim 1, wherein the isolation structure is overlapped with the circuitry region, and the isolation structure is electrically isolated from the pixel.

### Claim 3 (depends on 1)

The image sensor of claim 1, wherein the dielectric structure further covers a bottom surface of the conductive grid.

### Claim 4 (depends on 1)

The image sensor of claim 1, wherein a material of the conductive grid comprises a metal or a metal alloy.

### Claim 5 (depends on 1)

The image sensor of claim 1, further comprising:
an interconnect disposed along the second side of the substrate,
wherein the conductive structure is disposed through the isolation and electrically connected to a metal line of the interconnect the as conductive component.

### Claim 6 (depends on 5)

The image sensor of claim 5, wherein the conductive grid is separated from the substrate through the dielectric structure.

### Claim 7 (depends on 5)

The image sensor of claim 5, wherein a material of the conductive grid and a material of the conductive structure are identical.

### Claim 8 (depends on 5)

The image sensor of claim 5, wherein the isolation is a shallow trench isolation of dielectric material.

### Claim 9 (depends on 1)

The image sensor of claim 1, further comprising:
a conductive pattern, located on the substrate within the peripheral region, electrically connecting the conductive grid and the conductive structure, wherein the conductive pattern has a lateral surface covering a portion of a top surface of the conductive grid closer to the conductive structure and a top surface of the conductive structure.

### Claim 10 (depends on 9)

The image sensor of claim 9, wherein a material of the conductive structure and a material of the conductive pattern are identical.

### Claim 11 (depends on 10)

The image sensor of claim 10, wherein a material of the conductive grid and the material of the conductive structure are identical.

### Claim 12 (depends on 1)

The image sensor of claim 1, wherein the isolation comprises a doped region spatially and electrically connecting the conductive structure and the conductive component.

### Claim 13 (depends on 1)

The image sensor of claim 1,
wherein the conductive grid is in a form of solid bulk; and
wherein the conductive structure is in a form of a conformal layer with which a dielectric material is disposed between opposing sidewalls of the conductive structure.

### Claim 14

A semiconductor device, comprising:
a substrate having a first side and a second side opposite to the first side;
an interconnect, located on the first side;
a plurality of first isolations located in the substrate at the first side and electrically isolated from the interconnect;
a photodiode array, disposed in the substrate within an active region of the substrate and electrically connected to the interconnect;
an isolation structure, extending from the second side of the substrate to a position in the substrate within the active region, wherein the photodiode array is surrounded by and spaced apart from the isolation structure, and the isolation structure comprises a conductive grid; and
a plurality of conductive structures, disposed in the substrate within a peripheral region of the substrate and electrically connected to the interconnect, wherein the conductive grid is electrically connected to the interconnect through the conductive structures and is electrically isolated from the photodiode array,
wherein the conductive structures penetrate through the first isolations for electrically connecting to the interconnect.

### Claim 15 (depends on 14)

The semiconductor device of claim 14, wherein a portion of the isolation structure is located between two adjacent photodiodes of the photodiode array in the substrate within the active region along a direction perpendicular to a stacking direction of the substrate and the interconnect.

### Claim 16 (depends on 14)

The semiconductor device of claim 14, further comprising:
a plurality of second isolations, located in the substrate at the first side and electrically connected to the interconnect, wherein the conductive structures are in contact with the second isolations for electrically connecting to the interconnect, wherein the second isolations comprise doped regions.

### Claim 17

An image sensor, comprising:
a pixel in a substrate, the pixel comprising a photosensitive region and a circuitry region next to the photosensitive region;
a plurality of doped isolations disposed in the substrate at a first side and an interconnect disposed over the first side of the substrate;
an isolation structure disposed at a second side of the substrate opposite to the first side, the isolation structure comprising a first dielectric structure and a conductive grid on the first dielectric structure filling in a grid mesh cavity over the circuitry region and surrounding the photosensitive region; and
a plurality of conductive structures disposed next to the isolation structure in a plurality of openings at the second side of the substrate, wherein the conductive structures are electrically connected to the conductive grid of the isolation structure, and the isolation structure is electrically isolated from the pixel,
wherein the conductive structures are in contact with the doped isolations for electrically connecting the interconnect and the conductive grid through the doped isolations.

### Claim 18 (depends on 17)

The image sensor of claim 17, further comprising a second dielectric structure disposed in the plurality of openings under the plurality of conductive structures.

### Claim 19 (depends on 17)

The image sensor of claim 17, wherein the plurality of conductive structures extends for electrically connecting the interconnect and the conductive grid.

### Claim 20 (depends on 17)

The image sensor of claim 17,
wherein the doped isolations comprise stacks of doping regions of the same doping type and different doping concentrations.