# US 7,407,853 B2 · Display device and manufacturing method of the same

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- Number: US 7,407,853 B2
- Document ID: US7407853B2
- Status: Granted
- Kind: B2
- Application number: 11/077,255
- Filed: 2005-03-11
- Published: 2005-09-29
- Granted: 2008-08-05
- Earliest claimed: 2004-03-25
- Assignees: Hitachi Displays, Ltd.
- Inventors: Takuo Kaitoh; Eiji Oue; Takahiro Kamo; Yasukazu Kimura; Toshihiko Itoga
- Web page: https://patentgrep.com/patent/US7407853B2

## CPC

- G02F 1/136213: {Storage capacitors associated with the pixel electrode}
- H10D 86/0231: {using masks, e.g. half-tone masks}
- H10D 86/481: {integrated with passive devices, e.g. auxiliary capacitors}
- H10D 86/60: wherein the TFTs are in active matrices
- G02F 1/1368: in which the switching element is a three-electrode device {(G02F1/136277 takes precedence)}
- 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
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

The invention provides a method of manufacture of a display device which can achieve a reduction of the manufacturing process. In the manufacturing method, a semiconductor layer is formed over an upper surface of a substrate. An insulation film is formed over an upper surface of the semiconductor layer. Using a mask which covers a first region and exposes a second region, an implantation of impurities into the semiconductor layer is performed in the second region through the insulation film. After the mask is removed, a surface of the insulation film is etched in the first region and the second region to an extent that the insulation film in the second region remains, whereby the film thickness of the insulation film in the second region is set to be smaller than the film thickness of the insulation film in the first region.

## Claims

### Claim 1

A manufacturing method of a display device comprising the steps of:
forming a semiconductor layer over an upper surface of a substrate;
forming an insulation film over an upper surface of the semiconductor layer;
using a mask which covers a first region of the insulation film and exposes a second region of the insulation film, and performing an implantation of impurities into the semiconductor layer in the second region of the insulation film through the insulation film;
removing the mask after the step of performing the implantation of the impurities into the semiconductor layer; and
after the step of removing the mask, etching a surface of the insulation film in the first region and the second region to an extent that the insulation film in the second region remains, whereby a film thickness of the insulation film in the second region is set smaller than a film thickness of the insulation film in the first region.

### Claim 2 (depends on 1)

A manufacturing method of a display device according to claim 1, wherein a thin film transistor and a capacitive element are formed by using the insulation film in the first region as a gate insulation film of the thin film transistor and by using the insulation film in the second region as a dielectric film of the capacitive element.

### Claim 3 (depends on 1)

A manufacturing method of a display device according to claim 1, wherein the display device is a liquid crystal display device.

### Claim 4

A manufacturing method of a display device comprising the steps of:
forming a semiconductor layer over an upper surface of a substrate;
forming an insulation film over an upper surface of the semiconductor layer;
using a mask which covers a first region of the insulation film and exposes a second region of the insulation film, and performing an implantation of impurities into the semiconductor layer in the second region of the insulation film through the insulation film;
etching a surface of the insulation film in the second region to an extent that the insulation film in the second region remains while leaving the mask, whereby a film thickness of the insulation film in the second region is set smaller than a film thickness of the insulation film in the first region;
removing the mask; and
after the step of removing the mask, cleaning a surface of the insulation film in the first region and the second region.

### Claim 5 (depends on 4)

A manufacturing method of a display device according to claim 4, wherein a thin film transistor and a capacitive element are formed by using the insulation film in the first region as a gate insulation film of the thin film transistor and by using the insulation film in the second region as a dielectric film of the capacitive element.