# US 9,437,643 B2 · Semiconductor integrated circuit device

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- Number: US 9,437,643 B2
- Document ID: US9437643B2
- Status: Granted
- Kind: B2
- Application number: 14/840,707
- Filed: 2015-08-31
- Published: 2015-12-24
- Granted: 2016-09-06
- Earliest claimed: 2013-06-26
- Assignees: Renesas Electronics Corporation
- Applicants: Renesas Electronics Corporation
- Inventors: Kazuo Tomita; Takeshi Kawamura
- Web page: https://patentgrep.com/patent/US9437643B2

## CPC

- H10F 39/806: {Optical elements or arrangements associated with the image sensors}
- G02B 6/122: Basic optical elements, e.g. light-guiding paths
- G02B 6/4295: {coupling with semiconductor devices activated by light through the light guide, e.g. thyristors, phototransistors}
- H10F 39/024: {of coatings or optical elements}
- H10F 39/18: Complementary metal-oxide-semiconductor [CMOS] image sensors; Photodiode array image sensors
- H10F 39/802: {Geometry or disposition of elements in pixels, e.g. address-lines or gate electrodes}
- H10F 39/803: {Pixels having integrated switching, control, storage or amplification elements}
- H10F 39/805: {Coatings}
- H10F 39/8067: {Reflectors}
- G02B 2006/12061: {Silicon}
- G02B 2006/12123: {Diode}
- G02B 2006/12138: {Sensor}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

Provided is a semiconductor integrated circuit device having pixel regions in a photodiode array region and having, in each of the pixel regions, a waveguide holding hole having a substantially perpendicular sidewall above the photodiode and embedded with a silicon oxide-based sidewall insulating film reaching the bottom surface of the hole and two or more silicon nitride-based insulating films having a higher refractive index on the inner side of the hole. This structure makes it possible to prevent deterioration of pixel characteristics of an imaging device, such as CMOS sensor, which is rapidly decreasing in size.

## Claims

### Claim 1

A semiconductor integrated circuit device including a CMOS image sensor, comprising:
a photodiode formed in a semiconductor substrate and configuring a part of the CMOS image sensor;
an interlayer insulating film formed over the photodiode;
a waveguide holding hole formed in the interlayer insulating film above the photodiode;
a first silicon nitride-based insulating film formed over a side surface and a bottom surface of the waveguide holding hole;
a second silicon nitride-based insulating film formed over the first silicon nitride-based insulating film; and
a third silicon nitride-based insulating film formed over the second silicon nitride-based insulating film,
wherein the waveguide holding hole is embedded by the first, second and third silicon nitride-based insulating films,
wherein the second silicon nitride-based insulating film has a refractive index higher than that of the first silicon nitride-based insulating film, and
wherein the third silicon nitride-based insulating film has a refractive index higher than that of the second silicon nitride-based insulating film.

### Claim 2 (depends on 1)

A semiconductor integrated circuit device according to the claim 1,
wherein a width of the upper portion of the first silicon nitride-based insulating film is smaller than a width of the lower portion thereof, and
wherein a width of the upper portion of the second silicon nitride-based insulating film is smaller than a width of the lower portion thereof.

### Claim 3 (depends on 2)

A semiconductor integrated circuit device according to the claim 2,
wherein the waveguide holding hole is tapered toward the semiconductor substrate.

### Claim 4 (depends on 1)

A semiconductor integrated circuit device according to the claim 1,
wherein the waveguide holding hole is tapered toward the semiconductor substrate.

### Claim 5 (depends on 1)

A semiconductor integrated circuit device according to the claim 1,
wherein an anti-reflective film is formed between the interlayer insulating film and the photodiode.

### Claim 6 (depends on 5)

A semiconductor integrated circuit device according to the claim 5,
wherein the waveguide holding hole reaches the anti-reflective film.

### Claim 7 (depends on 5)

A semiconductor integrated circuit device according to the claim 5,
wherein the anti-reflective film includes a silicon nitride film and a silicon oxide film.