Method to prevent static destruction of an active element comprised in a liquid crystal display device

• US 20050082541A1
• Filed: 12/08/2004
• Published: 04/21/2005
• Est. Priority Date: 10/03/1995
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Satou, Takashi
• Application Number:
  US11/006,561
• Publication Number:
  US 20050082541A1
• Time in Patent Office: Days
• US Class Current: 257/72
• CPC Class Codes: G02F 1/136204 Arrangements to prevent high voltage or static electricity failures
• CPC Class Codes: G02F 2202/103 a-Si
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 27/0255 using diodes as protective elements
• CPC Class Codes: H01L 27/0266 using field effect transistors as protective elements
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/13091 Metal-Oxide-Semiconductor Field-Effect Transistor [MOSFET]

Abstract

A liquid crystal display device which utilizes an active matrix substrate and its substrate, and which is provided with a novel method of manufacture which can reduce the manufacturing process of amorphous silicon thin film transistors of reverse stagger construction, and an electrostatic protection means which is created using this method of manufacture. In a thin film transistor manufacturing process, along with forming an aperture for connecting the contact hole and the external terminal in a manufacturing process for a thin film transistor, utilization is made of ITO film as the wiring. The electrostatic protection means is formed from a bi-directional diode (electrostatic protection element) which is composed utilizing an MOS transistor connected between the electrode (PAD) for connecting the external terminal, and the joint electric potential line. The electrostatic protection element is substantially a transistor, with great current capacity, and utilizing the TFT formation process of pixel components in their existent state, the process can be formed without any complications.

Claims

1. An active matrix substrate, comprising:

a scanning line;

a signal line;

a pixel electrode;

a thin film transistor electrically connected to the scanning line, the signal line arranged in a matrix state and the pixel electrode to compose pixel components;

a protective circuit to prevent static electricity destruction using the thin film transistor established between at least one of the scanning line and the signal line, or a region electrically equivalent to the at least one of the scanning line and the signal line, and a common electric potential wiring other than the scanning line and the signal line, the protective circuit to prevent electrostatic destruction including a diode wherein a gate electrode layer in the thin film transistor and a source/drain electrode layer are connected; and

a first aperture formed by selectively removing an insulation layer on the gate electrode layer and a second aperture formed in a same manufacturing process by selectively removing an insulation layer on the source/drain electrode layer, the gate electrode layer and the source/drain electrode layer being electrically connected via the first aperture and second aperture by an electrically conductive material layer composed of the same material as the pixel electrode;

the region electrically equivalent being formed with a common electric potential line and

the common electric potential line being electrically connected to a facing electrode.

3. A liquid crystal display device, comprising:

the active matrix substrate according to claim 1.

2. An active matrix substrate, comprising:

a scanning line;

a signal line;

a pixel electrode;

a thin film transistor electrically connected to the scanning line, the signal line arranged in a matrix state and the pixel electrode to compose pixel components;

a protective circuit to prevent static electricity destruction using the thin film transistor established between at least one of the scanning line and the signal line, or a region electrically equivalent to the at least one of the scanning line and the signal line, and a common electric potential wiring other than the scanning line and the signal line, the protective circuit to prevent electrostatic destruction including a diode wherein a gate electrode layer in the thin film transistor and a source/drain electrode layer are connected; and

a first aperture formed by selectively removing an insulation layer on the gate electrode layer and a second aperture formed in a same manufacturing process by selectively removing an insulation layer on the source/drain electrode layer, the gate electrode layer and the source/drain electrode layer being electrically connected via the first aperture and second aperture by an electrically conductive material layer composed of the same material as the pixel electrode;

the region electrically equivalent being formed with a common electric potential line and

the common electric potential line having a gate electrode material wiring, a source material wiring, and a pixel electrode material connected between the gate electrode material wiring and the source material wiring.

4. A liquid crystal display device, comprising:

the active matrix substrate according to claim 2.