# US 9,040,341 B2 · Image device and methods of forming the same

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- Number: US 9,040,341 B2
- Document ID: US9040341B2
- Status: Granted
- Kind: B2
- Application number: 13/487,840
- Filed: 2012-06-04
- Published: 2013-12-05
- Granted: 2015-05-26
- Earliest claimed: 2012-06-04
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Wen-Chen Lu; Ching-Sen Kuo; Shih-Chi Fu; Ming-Ying Hsieh
- Inventors: Wen-Chen Lu; Ching-Sen Kuo; Shih-Chi Fu; Ming-Ying Hsieh
- Web page: https://patentgrep.com/patent/US9040341B2

## 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;
forming a first patterned mask layer over the pixel region to expose the periphery region;
etching a plurality of first trenches into the substrate in the periphery region;
filling each first trench, each first opening and each second opening with a dielectric material;
forming a second patterned mask layer over the periphery region to expose the pixel region;
removing the dielectric 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 first patterned mask layer includes a first type photoresist, and the second patterned mask layer includes a second type photoresist, wherein the first type is opposite to the second type.

### Claim 3 (depends on 1)

The method of claim 1, wherein the first patterned mask layer includes a negative photoresist.

### Claim 4 (depends on 1)

The method of claim 1, wherein the second patterned mask layer includes a positive photoresist.

### Claim 5 (depends on 1)

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

### Claim 6 (depends on 5)

The method of claim 5, 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 7 (depends on 1)

The method of claim 1, further comprising:
defining the first patterned mask layer by a first photomask; and
defining the second patterned mask layer by a second photomask, wherein the first photomask is the same as the second photomask.

### Claim 8 (depends on 1)

The method of claim 1, wherein the dopants comprise boron (B), BF2, gallium, indium or a combination thereof.

### 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 plurality of first openings in the periphery region, and a plurality of second openings in the pixel region;
forming a first patterned mask layer over the patterned hard mask layer in the pixel region to expose the periphery region;
etching a plurality of first trenches from the front surface in the periphery region;
filling each first trench, each first opening and each second opening with a dielectric material;
forming a second patterned mask layer over the patterned hard mask layer in the periphery region to expose the pixel region;
removing the dielectric material in each second opening over the pixel region;
implanting a dopants through each second opening to form doped isolation features in the pixel region;
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 10 (depends on 9)

The method of claim 9, wherein the first mask layer includes a first type photoresist, and the second mask layer includes a second type photoresist, wherein the first type is opposite to the second type.

### Claim 11 (depends on 9)

The method of claim 9, wherein the first mask layer includes a negative photoresist.

### Claim 12 (depends on 9)

The method of claim 9, wherein the second mask layer includes a positive photoresist.

### Claim 13 (depends on 9)

The method of claim 9, further comprising:
defining the first patterned mask layer by a first photomask; and
defining the second patterned mask layer by a second photomask, wherein the first photomask is the same as the second photomask.

### Claim 14 (depends on 9)

The method of claim 9, wherein each of the first trenches has a depth D1 into the substrate, the depth D1 is in a range from about 2000 Å to about 3500 Å.

### Claim 15 (depends on 9)

The method of claim 9, wherein each of the doped isolation features has a depth D2 into the substrate, the depth D2 is in a range from about 1000 Å to about 3000 Å.

### Claim 16 (depends on 9)

The method of claim 9, further comprising:
forming an isolation well region in the pixel region, wherein the isolation well region and the doped isolation features surround the at least one photodetector.

### Claim 17 (depends on 16)

The method of claim 16, wherein the isolation well region and the doped isolation features comprise boron (B), BF2, gallium, indium or combination thereof.

### Claim 18 (depends on 9)

The method of claim 9, wherein at least one of the first mask layer and the second mask layer includes a dielectric material that has a different etching resistance to the hard mask layer.

### Claim 19

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 plurality of first openings in the periphery region, and a plurality of second openings in the pixel region;
forming a first patterned photoresist over the patterned hard mask layer in the pixel region to expose the periphery region;
etching a plurality of first trenches from the front surface in the periphery region;
filling each first trench, each first opening and each second opening with a dielectric material;
forming a second patterned photoresist over the patterned hard mask layer in the periphery region to expose the pixel region;
removing the dielectric material in each second opening over the pixel region;
implanting dopants through each second opening to form doped isolation features in the pixel region;
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 19)

The method of claim 19, wherein the dopants comprise boron (B), BF2, gallium, indium or combination thereof.