TFT array substrate, liquid crystal display using TFT array substrate, and manufacturing method thereof

• US 6,317,174 B1
• Filed: 09/22/2000
• Issued: 11/13/2001
• Est. Priority Date: 11/09/1999
• Status: Expired due to Term

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Kabushiki Kaisha Advanced Display
• Inventors: Noumi, Shigeaki, Yabushita, Kouji
• Primary Examiner(s): Parker, Kenneth
• Assistant Examiner(s): QI, ZHI QIANG
• Application Number:
  US09/667,492
• Time in Patent Office: 417 Days
• Field of Search: 349/42, 349/43, 349/48, 438/30, 438/180, 438/365
• US Class Current: 349/42
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1244 for preventing breakage, peeling or short circuiting
• CPC Class Codes: H01L 27/1259 Multistep manufacturing methods

Abstract

A manufacturing method of a liquid crystal display is provided. The liquid crystal display having a picture element electrode formed on the uppermost layer of a structure is capable of reducing connection resistance between picture element electrode and drain electrode through interlayer insulating film. At the time of forming the picture element electrode, ITO film can be patterned into a desirable pattern without short circuit between assembled terminals in one etching process.

In the process of forming a contact hole 112 for connecting the picture element electrode 113 and the drain electrode 108 on the interlayer insulating film 111 and on the passivation film 110, a dry etching condition is established so that after the ashing process using O₂ gas to remove residue on the bottom of the contact hole 112, an etching process using fluorine gas+O₂ gas etc. is performed to reduce irregularity on the surface of the interlayer insulating film 111.

Claims

1. A manufacturing method of a liquid crystal display in which two transparent insulating substrates, at least on either of which an electrode is formed, are adhered facing to each other and a liquid crystal is held between the two transparent insulating substrates, comprising:

a step of forming a scanning electrode, a scanning electrode line and a scanning electrode line terminal on either of said two transparent insulating substrates;

a step of forming an insulating film on said scanning electrode, scanning electrode line and scanning electrode line terminal;

a step of forming a semiconductor layer on said scanning electrode through said insulating film;

a step of forming a first electrode, a first electrode line and a first electrode line terminal and a second electrode on said semiconductor layer;

a step of forming a passivation film on said first electrode, first electrode line, first electrode line terminal and second electrode;

a step of forming a contact hole on said second electrode and forming an interlayer insulating film having an aperture in an assembly region in which said scanning electrode line terminal and said first electrode line terminal are formed, by applying a transparent resin having a photosensitivity to said passivation film and by exposure and development;

a step of etching said passivation film and said insulating film exposed through said contact hole and said aperture by dry etching using said interlayer insulating film as a mask; and

a step of forming a transparent conductive film on said interlayer insulating film, in said contact hole, on said transparent insulating substrates exposed through said aperture, on said scanning electrode line terminal and on the first electrode line terminal, and forming a picture element electrode electrically connected to said second electrode through said contact hole and forming a transparent conductive film pattern on the scanning electrode line terminal and on the first electrode line terminal by patterning in just one etching process;

wherein the etching process using the interlayer insulating film or the resist as a mask, the second etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas is performed by setting a flow ratio of O₂ gas to be higher than that in the first etching process, after completing the first etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas.

2. A manufacturing method of a liquid crystal display in which two transparent insulating substrates, at least on either of which an electrode is formed, are adhered facing to each other and a liquid crystal is held between the two transparent insulating substrates, comprising:

a step of forming a scanning electrode, a scanning electrode line and a scanning electrode line terminal on either of said two transparent insulating substrates;

a step of forming an insulating film on said scanning electrode, scanning electrode line and scanning electrode line terminal;

a step of forming a semiconductor layer on said scanning electrode through said insulating film;

a step of removing said insulating film in an assembly region in which said scanning electrode line terminal and a first electrode line terminal are formed;

a step of forming a first electrode, a first electrode line and a first electrode line terminal and a second electrode on said semiconductor layer;

a step of forming a passivation film on said first electrode, first electrode line, first electrode line terminal and second electrode;

a step of forming a contact hole on said second substrate and forming an interlayer insulating film having an aperture in an assembly region in which said scanning electrode line terminal and said first electrode line terminal are formed, by applying a transparent resin having a photosensitivity to said passivation film and by exposure and development;

a step of etching the passivation film exposed through said contact hole and the aperture by dry etching using said interlayer insulating film as a mask; and

a step of forming a transparent conductive film on said interlayer insulating film, in said contact hole, on said transparent insulating substrates exposed through said aperture, on said scanning electrode line terminal and on the first electrode line terminal, and forming a picture element electrode electrically connected to said second electrode through said contact hole and forming a transparent conductive film pattern on the scanning electrode line terminal and on the first electrode line terminal by patterning in just one etching process;

wherein in the etching process by dry etching using the inter-layer insulating film as a mask, an ashing process using O₂ gas and a second etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas are performed, after completing a first etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas.

3. The manufacturing method of a liquid crystal display according to claim 2, wherein in the second etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas, the etching process is performed at a shorter time or by setting a flow ratio of O₂ gas to be higher or by setting a power to be smaller than that in the first etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas, or by combining at least two of said process conditions.

4. A manufacturing method of a liquid crystal display in which two transparent insulating substrates, at least on either of which an electrode is formed, are adhered facing to each other and a liquid crystal is held between the two transparent insulating substrates, comprising:

a step of forming a scanning electrode, a scanning electrode line and a scanning electrode line terminal on either of said two transparent insulating substrates;

a step of forming an insulating film on said scanning electrode, scanning electrode line and scanning electrode line terminal;

a step of forming a semiconductor layer on said scanning electrode through said insulating film;

a step of forming a first electrode, a first electrode line and a first electrode line terminal and a second electrode on said semiconductor layer;

a step of forming a passivation film on said first electrode, first electrode line, first electrode line terminal and second electrode;

a step of forming a contact hole on said second substrate and forming an interlayer insulating film having an aperture in an assembly region in which said scanning electrode line terminal and the first electrode line terminal are formed, by applying a transparent resin having a photosensitivity to said passivation film and by exposure and development;

a step of forming a resist by applying a photo-resist and patterning the photo-resist into the same configuration as the interlayer insulating film;

a step of removing the resist after etching the passivation film and the insulating film exposed through said contact hole and the aperture by dry etching using said resist as a mask; and

a step of forming a transparent conductive film on said interlayer insulating film, in said contact hole, on said transparent insulating substrates exposed through said aperture, on said scanning electrode line terminal and on the first electrode line terminal, and forming a picture element electrode electrically connected to said second electrode through said contact hole and forming a transparent conductive film pattern on said scanning electrode line terminal and on the first electrode line terminal by patterning in just one etching process.

5. The manufacturing method of a liquid crystal display according to claim 4, wherein the insulating film in the assembly region in which the scanning electrode line terminal and the first electrode line terminal are formed is removed after forming the semiconductor layer and before forming the first electrode, the first electrode line, the first electrode line terminals and the second electrode.

6. The manufacturing method of a liquid crystal display according to claim 5, wherein in the etching process using the interlayer insulating film or the resist as a mask, the second etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas is performed by setting a flow ratio of O₂ gas to be higher than that in the first etching process, after completing the first etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas.

7. The manufacturing method of a liquid crystal display according to claim 5, wherein in the etching process by dry etching after forming the resist on the interlayer insulating film, an ashing process using O₂ gas is performed after the etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas.

8. The manufacturing method of a liquid crystal display according to claim 4, wherein in etching process by dry etching after forming the resist on the interlayer insulating film, an ashing process using O₂ gas is performed after the etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas.

9. The manufacturing method of a liquid crystal display according to claim 4, wherein in the etching process using the interlayer insulating film or the resist as a mask, the second etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas is performed by setting a flow ratio of O₂ gas to be higher than that in the first etching process, after completing the first etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas.

10. A manufacturing method of a liquid crystal display in which two transparent insulating substrates, at least on either of which an electrode is formed, are adhered facing to each other and a liquid crystal is held between the two transparent insulating substrates, comprising:

a step of forming a scanning electrode, a scanning electrode line and a scanning electrode line terminal on either of said two transparent insulating substrates;

a step of forming an insulating film on said scanning electrode, scanning electrode line and scanning electrode line terminal;

a step of forming a semiconductor layer on said scanning electrode through said insulating film;

a step of forming a first electrode, a first electrode line and a first electrode line terminal and a second electrode on said semiconductor layer;

a step of forming a passivation film on said first electrode, first electrode line, first electrode line terminal and second electrode;

a step of forming an interlayer insulating film by applying a transparent resin having no photosensitivity to said passivation film;

a step of forming a resist, and removing the resist after forming a contact hole on said second electrode and an aperture in an assembly region in which said scanning electrode line terminal and the first electrode line terminal are formed, by etching said interlayer insulating film, passivation film and insulating film by dry etching; and

a step of forming a transparent conductive film on said interlayer insulating film, in said contact hole, on said transparent insulating substrates exposed through said aperture, on said scanning electrode line terminal and on the first electrode line terminal, and forming a picture element electrode electrically connected to said second electrode through said contact hole and forming a transparent conductive film pattern on said scanning electrode line terminal and on the first electrode line terminal by patterning in just one etching process.

11. The manufacturing method of a liquid crystal display according to claim 10, wherein the insulating film in the assembly region in which the scanning electrode line terminal and the first electrode line terminal are formed is removed after forming the semiconductor layer and before forming the first electrode, the first electrode line, the first electrode line terminals and the second electrode.

12. The manufacturing method of a liquid crystal display according to claim 11, wherein in the etching process using the interlayer insulating film or the resist as a mask, the second etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas is performed by setting a flow ratio of O₂ gas to be higher than that in the first etching process, after completing the first etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas.

13. The manufacturing method of a liquid crystal display according to claim 10, wherein in the etching process using the interlayer insulating film or the resist as a mask, the second etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas is performed by setting a flow ratio of O₂ gas to be higher than that in the first etching process, after completing the first etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas.

14. The manufacturing method of a liquid crystal display according to claim 10, wherein in the etching process by dry etching after forming the resist on the interlaycr insulating film, an ashing process using O₂ gas is performed after the etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas.

15. A manufacturing method of a liquid crystal display in which two transparent insulating substrates, at least on either of which an electrode is formed, are adhered facing to each other and a liquid crystal is held between the two transparent insulating substrates, comprising:

a step of forming a scanning electrode, a scanning electrode line and a scanning electrode line terminal on either of said two transparent insulating substrates;

a step of forming an insulating film on said scanning electrode, scanning electrode line and scanning electrode line terminal;

a step of forming a semiconductor layer on said scanning electrode through said insulating film;

a step of forming a first electrode, a first electrode line and a first electrode line terminal and a second electrode on said semiconductor layer;

a step of forming a passivation film on said first electrode, first electrode line, first electrode line terminal and second electrode;

a step of forming a contact hole on said second electrode and forming an interlayer insulating film having an aperture in an assembly region in which said scanning electrode line terminal and said first electrode line terminal are formed, by applying a transparent resin having a photosensitivity to said passivation film and by exposure and development;

a step of etching said passivation film and said insulating film exposed through said contact hole and said aperture by dry etching using said interlayer insulating film as a mask; and

a step of forming a transparent conductive film on said interlayer insulating substrates exposed through said aperture, in said contact hole, on said transparent insulating substrates exposed through said aperture, on said scanning electrode line terminal and on the first electrode line terminal, and forming a picture element electrode electrically connected to said second electrode through said contact hole and forming a transparent conductive film pattern on the scanning electrode line terminal and on the first electrode line terminal by patterning in just one etching process;

wherein in the etching process by dry etching using the inter-layer insulating film as a mask, an ashing process using O₂ gas and a second etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas are performed, after completing a first etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas.

16. The manufacturing method of a liquid crystal display according to claim 15, wherein in the second etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas, the etching process is performed in a shorter time or by setting a flow ratio of O₂ gas to he higher or by setting a power to be smaller than that in the first etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas, or by combining at least two of said process conditions.

17. A manufacturing method of a liquid crystal display in which two transparent insulating substrates, at least on either of which an electrode is formed, are adhered facing to each other and a liquid crystal is held between the two transparent insulating substrates, comprising:

a step of forming a scanning f electrode, a scanning electrode line and a scanning electrode line terminal on either of said two transparent insulating substrates;

a step of forming an insulating film on said scanning electrode, scanning electrode line and scanning electrode line terminal;

a step of forming a semiconductor layer on said scanning electrode through said insulating film;

a step of removing said insulating film in an assembly region in which said scanning electrode line terminal and a first electrode line terminal are formed;

a step of forming a first electrode, a first electrode line and a first electrode line terminal and a second electrode on said semiconductor layer;

a step of forming a passivation film on said first electrode, first electrode line, first electrode line terminal and second electrode;

a step of forming a contact hole on said second substrate and forming an interlayer insulating film having an aperture in an assembly region in which said scanning electrode line terminal and said first electrode line terminal are formed, by applying a transparent resin having a photosensitivity to said passivation film and by exposure and development;

a step of etching the passivation film exposed through said contact hole and the aperture by dry etching using said interlayer insulating film as a mask; and

a step of forming a transparent conductive film on said interlayer insulating film, in said contact hole, on said transparent insulating substrates exposed through said aperture, on said scanning electrode line terminal and on the first electrode line terminal, and forming a picture element electrode electrically connected to said second electrode through said contact hole and forming a transparent conductive film pattern on the scanning electrode line terminal and on the first electrode line terminal by patterning in just one etching process; and

in the etching process using the interlayer insulating film or the resist as a mask, the second etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas is performed by setting a flow ratio of O₂ gas to be higher than that in the first etching process, after completing the first etching process using CF₄+O₂, SF₆+O₂ or other fluorine gas+O₂ gas.