# US 7,612,395 B2 · CMOS image sensors

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- Number: US 7,612,395 B2
- Document ID: US7612395B2
- Status: Granted
- Kind: B2
- Application number: 11/441,295
- Filed: 2006-05-24
- Published: 2006-09-21
- Granted: 2009-11-03
- Earliest claimed: 2003-12-31
- Assignees: Dongbu Electronics Co., Ltd.
- Inventors: In Gyun Jeon
- Web page: https://patentgrep.com/patent/US7612395B2

## CPC

- H10F 39/024: {of coatings or optical elements}
- H10F 39/014: {of CMOS image sensors}
- H10F 39/18: Complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors
- H10F 39/8053: {Colour filters}
- H10F 39/8063: {Microlenses}
- H10F 39/803: {Pixels having integrated switching, control, storage or amplification elements}
- H10F 77/331: {for filtering or shielding light, e.g. multicolour filters for photodetectors}
- H10F 77/40: Optical elements or arrangements (surface textures H10F77/70)
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

CMOS image sensors and methods for fabricating the same are disclosed. A disclosed CMOS image sensor comprises: a semiconductor substrate; a photo diode; a microlens located over the photo diode; and a color filter layer located over the microlens.

## Claims

### Claim 1

A CMOS image sensor comprising:
a semiconductor substrate;
a photodiode on the semiconductor substrate;
an insulating film on the semiconductor substrate, over the photodiode;
a microlens that is wider than the photodiode, comprising:
i) a first dielectric film on the insulating film and over the photodiode, the first dielectric film having a first refractive index;
ii) a second dielectric directly film on the first dielectric film, the second dielectric film having a second refractive index lower than the first refractive index; and
iii) a sidewall dielectric film directly on at sidewalls of each of the first and second dielectric films and on the insulating film, the sidewall dielectric film having a curved outer surface and a refractive index equal to the first refractive index; and
a fourth dielectric film on the insulating film and on the microlens.

### Claim 2 (depends on 1)

A CMOS image sensor as claimed in claim 1, wherein the first index of refraction is higher than an index of refraction of the second and fourth dielectric film.

### Claim 3 (depends on 1)

A CMOS image sensor as claimed in claim 1, wherein the indices of refraction of the first dielectric and sidewall dielectric films are about 1.8˜2.2, and the indices of refraction of the second and fourth dielectric films are about 1.3˜1.7.

### Claim 4 (depends on 1)

A CMOS image sensor as claimed in claim 1, wherein widths of the first and second dielectric films are substantially identical to a width of the photodiode.

### Claim 5 (depends on 1)

A CMOS image sensor as claimed in claim 1, wherein the first dielectric and sidewall dielectric films comprise nitride films.

### Claim 6 (depends on 1)

A CMOS image sensor as claimed in claim 1, further comprising a color filter layer located on the fourth dielectric film over the photodiode.

### Claim 7 (depends on 1)

A CMOS image sensor as claimed in claim 1, wherein the photodiode is in an epitaxial layer on the substrate.

### Claim 8 (depends on 7)

A CMOS image sensor as claimed in claim 7, further comprising a device isolation layer in the epitaxial layer and adjacent to the photodiode.

### Claim 9 (depends on 4)

A CMOS image sensor as claimed in claim 4, wherein the width of each of the first and second dielectric films are about 05˜2 μm.

### Claim 10 (depends on 7)

A CMOS image sensor as claimed in claim 7, further comprising a depletion region in the epitaxial layer.

### Claim 11 (depends on 1)

A CMOS image sensor as claimed in claim 1, wherein the insulating film comprises a light shielding layer.

### Claim 12 (depends on 7)

A CMOS image sensor as claimed in claim 7, wherein the photodiode comprises a region of the epitaxial layer containing N-type impurity ions.

### Claim 13 (depends on 1)

A CMOS image sensor as claimed in claim 1, wherein the first dielectric film has a thickness of about 5,000˜15,000 Å.

### Claim 14 (depends on 1)

A CMOS image sensor as claimed in claim 1, wherein the second dielectric film has a thickness of about 5,000˜15,000 Å.

### Claim 15 (depends on 1)

A CMOS image sensor as claimed in claim 1, wherein the sidewall dielectric film forms a sidewall spacer at the sidewalls of the first and second dielectric films.

### Claim 16 (depends on 15)

A CMOS image sensor as claimed in claim 15, wherein the sidewall dielectric film has a thickness at an interface wit the sidewalls of the first and second dielectric films about equal to a combined thickness of the first and second dielectric films.

### Claim 17 (depends on 7)

A CMOS image sensor as claimed in claim 7, wherein the first and second dielectric films are substantially aligned with the underlying photodiode, and substantially all of the sidewall dielectric film is over the area of the epitaxial layer that is lateral to die photodiode and surrounds the photodiode.

### Claim 18 (depends on 1)

A CMOS image sensor as claimed in claim 1, wherein the second and fourth dielectric films each comprise an oxide film.

### Claim 19 (depends on 1)

A CMOS image sensor as claimed in claim 1, wherein the insulating layer comprises an oxide film.

### Claim 20 (depends on 6)

A CMOS image sensor as claimed in claim 6, wherein the color filter layer is over the first and second dielectric layers and at least a portion of the sidewall dielectric layer.