# US 9,437,650 B2 · Image device and methods of forming the same

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- Number: US 9,437,650 B2
- Document ID: US9437650B2
- Status: Granted
- Kind: B2
- Application number: 14/721,782
- Filed: 2015-05-26
- Published: 2015-09-10
- Granted: 2016-09-06
- Earliest claimed: 2012-06-04
- Assignees: Taiwam Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Wen-Chen Lu; Ching-Sen Kuo; Shih-Chi Fu; Ming-Ying Hsieh
- Web page: https://patentgrep.com/patent/US9437650B2

## CPC

- H10F 39/026: {Wafer-level processing}
- H10F 39/014: {of CMOS image sensors}
- H10F 39/024: {of coatings or optical elements}
- H10F 39/199: {Back-illuminated image sensors}
- H10F 39/807: {Pixel isolation structures}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

A method of forming of an image sensor device includes a patterned hardmask layer is formed over a substrate. The patterned hard mask layer has a plurality of first openings in a periphery region, and a plurality of second openings in a pixel region. A first patterned mask layer is formed over the pixel region to expose the periphery region. A plurality of first trenches is etched into the substrate in the periphery region. Each first trench, each first opening and each second opening are filled with a dielectric material. A second patterned mask layer is formed over the periphery region to expose the pixel region. The dielectric material in each second opening over the pixel region is removed. A plurality of dopants is implanted through each second opening to form various doped isolation features in the pixel region.

## Claims

### Claim 1

A method of forming an image sensor device, the method comprising:
forming a patterned hard mask layer over a substrate, wherein the patterned hard mask layer has a plurality of first openings in a periphery region of the substrate, and a plurality of second openings in a pixel region of the substrate;
etching the substrate through the plurality of first openings to form a plurality of first trenches in the substrate;
filling each first trench, each first opening and each second opening with a material;
removing the material in each second opening over the pixel region; and
implanting dopant through each second opening to form doped isolation features in the pixel region.

### Claim 2 (depends on 1)

The method of claim 1, wherein the material is a dielectric material.

### Claim 3 (depends on 1)

The method of claim 1, wherein forming a patterned hard mask comprises etching a hard mask through a patterned photoresist layer.

### Claim 4 (depends on 1)

The method of claim 1, further comprising:
forming at least one photodetector in the pixel region, wherein the at least one photodetector is surrounded by the doped isolation features; and
forming a doped layer in a back surface of the substrate.

### Claim 5 (depends on 4)

The method of claim 4, further comprising: forming a color filter and a lens over the back surface of the substrate, wherein the color filter and the lens are aligned with the at least one photodetector.

### Claim 6 (depends on 1)

The method of claim 1, further comprising forming a light-sensing region in the pixel region surrounded by the doped isolation features.

### Claim 7 (depends on 6)

The method of claim 6, wherein the light-sensing region has a first conductivity type and the doped isolation features have a second conductivity type opposite to the first conductivity type.

### Claim 8 (depends on 1)

The method of claim 1, further comprising:
defining the patterned hard mask layer by a first photomask.

### Claim 9

A method of forming an image sensor device, the method comprising:
providing a substrate having a front surface and a back surface, and a pixel region and a periphery region;
forming a patterned hard mask layer over the front surface of the substrate, wherein the patterned hard mask layer has a first opening in the periphery region, and a second opening in the pixel region;
etching a trench in the front surface of the substrate in the periphery region through the first opening;
filling the trench, the first opening and the second opening with a material;
removing the material in the second opening over the pixel region, while leaving the material intact in the trench; and
implanting a dopant through the second opening to form a doped isolation feature in the pixel region.

### Claim 10 (depends on 9)

The method of claim 9, further comprising: forming at least one photodetector in the substrate of the pixel region, wherein the at least one photodetector is surrounded by the doped isolation features; and
forming a color filter and a lens over the back surface of the substrate, wherein the color filter and the lens are aligned with the at least one photodetector.

### Claim 11 (depends on 9)

The method of claim 9, further comprising:
forming a first patterned mask layer over the patterned hard mask layer in the pixel region to expose the periphery region; and
forming a second patterned mask layer over the patterned hard mask layer in the periphery region to expose the pixel region.

### Claim 12 (depends on 11)

The method of claim 11, wherein the first mask layer is one of a positive photoresist or a negative photoresist, and the second mask layer is the opposite one of a positive photoresist or a negative photoresist.

### Claim 13 (depends on 9)

The method of claim 9, further comprising forming at least one light-sensing region in the pixel region surrounded by the doped isolation features.

### Claim 14 (depends on 13)

The method of claim 13, wherein at least one light-sensing region has a first conductivity type and the doped isolation features have a second conductivity type opposite to the first conductivity type.

### Claim 15 (depends on 9)

The method of claim 9, further comprising:
defining the patterned mask layer by a first photomask.

### Claim 16 (depends on 9)

The method of claim 9, wherein the trench extends into the substrate with a depth of from about 2000 Å to about 3500 Å.

### Claim 17 (depends on 9)

The method of claim 9, wherein the doped isolation feature extends into the substrate with a depth of from about 1000 Å to about 3000 Å.

### Claim 18

A method of forming an image sensor device, the method comprising:
providing a substrate having a front surface and a back surface, and a pixel region and a periphery region;
forming a patterned hard mask layer over the front surface of the substrate, wherein the patterned hard mask layer has a first opening in the periphery region, and a second opening in the pixel region;
forming a first patterned photoresist covering the patterned hard mask layer in the pixel region and exposing the patterned hard mask in the periphery region;
etching a trench through the first opening;
filling the trench, the first opening and the second opening with a material;
forming a second patterned photoresist over the patterned hard mask layer covering the periphery region and exposing the pixel region;
removing the material in the second opening; and
implanting a dopant through the second opening into the substrate to form a doped isolation feature in the pixel region.

### Claim 19 (depends on 18)

The method of claim 18, further comprising:
forming at least one photodetector in the substrate of the pixel region, wherein the at least one photodetector is surrounded by the doped isolation features; and
forming a doped layer in the back surface of the substrate.

### Claim 20 (depends on 18)

The method of claim 18, wherein the dopant comprises boron (B), BF2, gallium, indium or combination thereof.