# US 8,148,727 B2 · Display device having oxide thin film transistor and fabrication method thereof

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- Number: US 8,148,727 B2
- Document ID: US8148727B2
- Status: Granted
- Kind: B2
- Application number: 13/166,478
- Filed: 2011-06-22
- Published: 2011-10-13
- Granted: 2012-04-03
- Earliest claimed: 2009-06-02
- Assignees: LG Display Co., Ltd.
- Inventors: Im-Kuk Kang; Dae-Won Kim
- Web page: https://patentgrep.com/patent/US8148727B2

## CPC

- H10D 86/60: wherein the TFTs are in active matrices
- G02F 1/1333: Constructional arrangements; {Manufacturing methods}(G02F1/135, G02F1/136 take precedence)
- H10D 30/6739: {Conductor-insulator-semiconductor electrodes}
- H10D 86/0231: {using masks, e.g. half-tone masks}
- H10D 86/40: characterised by multiple TFTs
- H10D 86/423: {comprising semiconductor materials not belonging to the Group IV, e.g. InGaZnO}
- H10W 20/484: {Interconnections having extended contours, e.g. pads having mesh shape or interconnections comprising connected parallel stripes}
- G02F 1/136231: {for reducing the number of lithographic steps}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A display device including an oxide thin film transistor (TFT) is disclosed. A nitride-based gate insulating layer of a gate pad area is etched when an oxide semiconductor layer of a pixel area is etched by using a half-tone mask, a metal layer is formed at a contact hole of the etched gate insulting layer, and then a passivation layer formed thereon is etched. Thus, an overhang of the passivation layer can be prevented from being generated when the gate insulating layer is etched, and accordingly, the fabrication process can be simplified.

## Claims

### Claim 1

A display device comprising:
first and second substrates including a pixel area, a gate pad area, and a data pad area;
an oxide thin film transistor (TFT) formed at the pixel area of the first substrate, the oxide thin film transistor including a gate electrode on the first substrate, a gate insulating layer on the whole area of the first substrate, an oxide semiconductor layer on the gate insulating layer, and source and drain electrodes on the oxide semiconductor layer;
a gate pad and a data pad at the gate pad area and the data pad area of the first substrate;
a metal layer on the gate insulating layer at the gate pad area and connected with the gate pad via a contact hole in the gate insulating layer;
a passivation layer on the whole area of the first substrate;
a pixel electrode on the passivation layer of the pixel area;
first and second transparent conductive layers at the gate pad area and the data pad area, respectively; and
a liquid crystal layer between the first and second substrates.

### Claim 2 (depends on 1)

The device of claim 1, wherein the oxide semiconductor layer is made of oxide containing at least one of Zn, In, Ga, or their mixture.

### Claim 3 (depends on 1)

The device of claim 1, wherein the gate insulating layer includes SiNx.

### Claim 4 (depends on 1)

The device of claim 1, wherein the passivation layer is made of SiO2.

### Claim 5 (depends on 1)

The device of claim 1, wherein the metal layer is made of the same material as that of the source electrode of the oxide TFT.