# US 2014/0151840 A1 · Method and Apparatus for CMOS Sensor Packaging

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- Number: US 2014/0151840 A1
- Document ID: US20140151840A1
- Status: Published application
- Kind: A1
- Application number: 13/693,591
- Filed: 2012-12-04
- Published: 2014-06-05
- Earliest claimed: 2012-12-04
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, L
- Inventors: Ching-Hung Cheng
- Web page: https://patentgrep.com/patent/US20140151840A1

## CPC

- H10F 39/811: {Interconnections}
- H10F 39/011: {Manufacture or treatment of image sensors covered by group H10F39/12}
- H10F 39/199: {Back-illuminated image sensors}
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION

## Abstract

Methods and apparatus for forming a bond pad of a semiconductor device such as a backside illuminated (BSI) image sensor device are disclosed. The substrate of a device may have an opening at the backside, through the substrate reaching the first metal layer at the front side of the device. A buffer layer may be formed above the backside of the substrate and covering sidewalls of the substrate opening. A pad metal layer may be formed above the buffer layer and in contact with the first metal layer at the bottom of the substrate opening. A bond pad may be formed in contact with the pad metal layer. The bond pad is connected to the pad metal layer vertically above the substrate, and further connected to the first metal layer of the device at the opening of the substrate.

## Claims

### Claim 1

A device, comprising:
a substrate with a front side and a backside;
a first metal layer on the front side of the substrate;
a first opening having sidewalls and a bottom, extending from the backside, through the substrate, and reaching the first metal layer at the front side;
a buffer layer on the backside of the substrate and on sidewalls of the first opening;
a pad metal layer on the buffer layer, over the sidewalls and the bottom of the first opening, in contact with the first metal layer; and
a bond pad in contact with the pad metal layer.

### Claim 2 (depends on 1)

The device of claim 1, further comprising a passivation layer on the pad metal layer, wherein the bond pad is located within an opening in the passivation layer.

### Claim 3 (depends on 1)

The device of claim 1, wherein the bond pad is vertically above a first area of the substrate, the first area is vertically separated from a second area of the substrate comprising a photosensitive diode within.

### Claim 4 (depends on 1)

The device of claim 1, further comprising an inter-layer dielectric (ILD) layer at the front side of the substrate between the substrate and the first metal layer, wherein the first opening extends through the ILD layer.

### Claim 5 (depends on 1)

The device of claim 1, further comprising an isolation area within the substrate, wherein the first opening is formed through the isolation area.

### Claim 6 (depends on 1)

The device of claim 1, wherein the pad metal layer comprises a conductive material selected from the group consisting essentially of copper, nickel, gold, aluminum, alloys thereof, and combinations thereof.

### Claim 7 (depends on 1)

The device of claim 1, wherein the pad metal layer has a height from about 0.2 μm to about 2.0 μm.

### Claim 8 (depends on 1)

The device of claim 1, wherein the bond pad comprises a conductive material selected from the group consisting essentially of copper, nickel, gold, aluminum, alloys thereof, and combinations thereof.

### Claim 9 (depends on 1)

The device of claim 1, wherein the buffer layer comprises a material selected from the group consisting essentially of SiO2, SiN, SiON, SiC, or combinations thereof.

### Claim 10

A method for processing a device, comprising:
providing a substrate with a front side and a backside;
forming a first metal layer on the front side of the substrate;
forming a first opening having sidewalls and a bottom, the first opening extending from the backside through the substrate to the first metal layer;
forming a buffer layer on the backside of the substrate, and on the sidewalls and the bottom of the first opening;
forming a second opening in the buffer layer at the bottom of the first opening to expose the first metal layer;
forming a pad metal layer on the buffer layer, on the sidewalls and the bottom of the first opening, and in contact with the first metal layer; and
forming a bond pad in contact with the pad metal layer.

### Claim 11 (depends on 10)

The method of claim 10, wherein forming the bond pad comprises:
forming a passivation layer on the pad metal layer;
forming an opening in the passivation layer to expose the pad metal layer; and
forming the bond pad within the opening of the passivation layer and in contact with the pad metal layer.

### Claim 12 (depends on 10)

The method of claim 10, wherein forming the bond pad comprises:
forming the bond pad vertically above a first area of the substrate, the first area is vertically separated from a second area of the substrate comprising a photosensitive diode within.

### Claim 13 (depends on 12)

The method of claim 12, wherein forming the pad metal layer comprises:
forming the pad metal layer on the buffer layer, on the sidewalls and the bottom of the first opening, and in contact with the first metal layer; and
forming an opening of the pad metal layer vertically above the first area of the substrate so that the pad metal layer comprises a first segment vertically above the first area of the substrate, and the bond pad is connected to the first segment of the pad metal layer.

### Claim 14 (depends on 10)

The method of claim 10, wherein forming the first opening comprises:
forming the first opening through an inter-layer dielectric (ILD) layer at the front side of the substrate between the substrate and the first metal layer.

### Claim 15

A device, comprising:
a substrate with a front side and a backside;
a first metal layer on the front side of the substrate;
a first opening having sidewalls and a bottom, extending from the backside, through the substrate, and reaching the first metal layer at the front side;
a buffer layer on the backside of the substrate and on sidewalls of the first opening;
a pad metal layer on the buffer layer, over the sidewalls and the bottom of the first opening, in contact with the first metal layer;
a passivation layer on the pad metal layer with a second opening of the passivation layer to expose the pad metal layer; and
a bond pad within the second opening of the passivation layer and in contact with the pad metal layer.

### Claim 16 (depends on 15)

The device of claim 15, wherein the bond pad is vertically above a first area of the substrate, the first area is vertically separated from a second area of the substrate comprising a photosensitive diode within.

### Claim 17 (depends on 15)

The device of claim 15, further comprising an inter-layer dielectric (ILD) layer at the front side of the substrate between the substrate and the first metal layer, wherein the first opening extends through the ILD layer.

### Claim 18 (depends on 15)

The device of claim 15, further comprising an isolation area within the substrate, wherein the first opening is formed through the isolation area.

### Claim 19 (depends on 15)

The device of claim 15, wherein the pad metal layer comprises a conductive material selected from the group consisting essentially of copper, nickel, gold, aluminum, alloys thereof, and combinations thereof.

### Claim 20 (depends on 15)

The device of claim 15, wherein the buffer layer comprises a material selected from the group consisting essentially of SiO2, SiN, SiON, SiC, or combinations thereof.