KR100232682B1 - Structure and manufacturing method of liquid crystal display device - Google Patents

Abstract

The present invention is characterized in that a benzocyclobutene (BCB), which is an organic insulating material having a relative dielectric constant of 3.0 or less, is used as a gate insulating film and a protective film in a method of manufacturing an IOP (ITO on passivation) .

This organic insulating film has a good line step characteristic and can prevent a line step from occurring at an intersection portion between the gate bus line 18 and the data bus line 19 or the like and can prevent the data bus line 19 or the like A domain phenomenon does not occur even if the pixel electrode 15 is formed over the pixel electrode 15, so that a liquid crystal display device with high aperture ratio and display quality can be manufactured.

Description

Method of manufacturing liquid crystal display device and structure of liquid crystal display device

FIG. 1 is a sectional view of a liquid crystal display device for explaining a conventional technique; FIG.

FIG. 2 is a plan view of a liquid crystal display device for explaining a conventional technique; FIG.

3 is a cross-sectional view taken along line III-III of FIG. 2;

FIG. 4 is a perspective view showing an intersection point of a conventional gate bus line and a data bus line; FIG.

FIG. 5 is a plan view of the liquid crystal display device of the present invention. FIG.

FIG. 6 is a process sectional view of line VI-VI of FIG. 5 for explaining Example 1. FIG.

FIGS. 7 and 9 are process sectional views of the VII-VII line of FIG. 5 for explaining Example 2. FIG.

FIG. 8 is a perspective view showing the intersections of gate bus lines and data bus lines of the present invention. FIG.

DESCRIPTION OF THE REFERENCE NUMERALS

11, 12: transparent substrate 15: pixel electrode

16: TFT 17: common electrode

13: seal 14: liquid crystal

18: gate bus line 19: data bus line

34: shielding metal film 18a: gate electrode

28a: organic insulating film 28b: inorganic insulating film

35: etch stopper layer 18a: gate electrode

19a: source electrode 19b: drain electrode

23: gate insulating film 22: semiconductor layer

25: ohmic contact layer 26: protective film

36: anodic oxide film 31: contact hole

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device incorporating a thin film transistor (hereinafter referred to as TFT), and more particularly to a structure and a manufacturing method of a TFT.

In the liquid crystal display of this kind, for example, as shown in FIGS. 1 and 2, the transparent substrates 11 and 12 are separated by a spacer (not shown) for holding a cell gap And are provided so as to face each other at a predetermined interval at which the liquid crystal can be injected.

The unexplained reference numeral 13 is a seal member for sealing the injected liquid crystal.

A plurality of pixel electrodes 15 are formed on the inner surface of one of the transparent substrates 11.

A TFT 16, which can be a switching element, is formed in each pixel electrode 15.

And the drain electrode of the TFT is connected to the pixel electrode.

A transparent common electrode 17 is formed on the inner surface of the other transparent substrate 12 opposite to the plurality of pixel electrodes 15. [

In the pixel electrode 15, for example, as shown in FIG. 2, square-shaped pixel electrodes are arranged on the transparent substrate 11 in the longitudinal and transverse directions.

Gate bus lines 18 are formed adjacent to the lateral direction of the pixel electrodes 15, respectively.

Further, a data bus line 19 is formed close to the longitudinal direction of the pixel electrode 15.

A TFT 16 is provided at the intersection of the gate bus line 18 and the data bus line 19.

The gate electrode of the TFT provided at each intersection portion is branched at the gate bus line 18 and the source electrode is branched at the data bus line 19. [

When a voltage is applied to each of the gate bus line 18 and the data bus line 19, only the TFT 16 to which the voltage is applied is turned on, A voltage is applied to only the portion of the liquid crystal 14 between the pixel electrode 15 and the common electrode 17 by accumulating charges in the liquid crystal layer 15.

The liquid crystal to which the voltage is applied changes the angle of the liquid crystal molecules, and transmits or blocks light according to the angle of the liquid crystal molecules.

By using the above-described principle, it is possible to selectively control transmission and blocking of light for each pixel electrode 15.

The conventional transparent substrate 11 including the TFT 16 is constructed as shown in FIGS. 2 and 3, for example.

A gate bus line 18 formed laterally on the transparent substrate 11 and a gate electrode 18a branched vertically on the gate bus line 18 are formed.

The gate electrode 18a is anodized to improve insulation and prevent hillock.

A gate insulating film 23 made of an inorganic film such as silicon nitride (SiNx) or silicon oxide (SiOx) is formed on the transparent substrate 11 on which the gate electrode 18a is formed.

A semiconductor layer 22 such as amorphous silicon (hereinafter referred to as a-Si) is formed on the gate insulating film 23 of the gate electrode 18a.

An ohmic contact layer 25 is formed on the semiconductor layer 22 such as a-Si.

A data bus line 19 formed in the longitudinal direction and a source electrode 19a and a drain electrode 19b branched in the horizontal direction in the data bus line 19 are formed.

The source electrode 19a and the drain electrode 19b are formed to be in contact with the ohmic contact layer 25.

A protective film 26 made of an inorganic film such as silicon nitride (SiNx) is formed to cover the source / drain electrodes and the like and a transparent conductive film ITO (Indium Tin Oxide) film is formed on the passivation film 26 to constitute the pixel electrode 15.

As shown in FIG. 4, the conventional liquid crystal display device has a structure in which an anodic oxide film 36 and a SiNx film are formed on the gate bus line 18, as shown in FIG. 4, A gate insulating film 23 made of an inorganic film such as SiOx and a data bus line 19 made of Cr metal are formed.

Since the gate insulating film made of the inorganic film goes over the line step as it is, the data bus line formed on the gate insulating film goes over the line step as it is.

That is, since the inorganic insulating film has a poor line step characteristic, the data bus line may be broken by a stress of the data bus line 19 or the like in a step portion indicated by a dotted line in FIG.

Also, the parasitic capacitance of the stepped portion may cause a delay problem of the gate bus line in a circuit.

When a pixel electrode formed on a protective film made of an inorganic insulating film is formed to overlap with a data bus line or the like in order to increase the aperture ratio in the conventional liquid crystal display device, The orientation state of the molecules may be different.

The occurrence of orientation in a direction other than the desired direction as described above is called a domain phenomenon.

The domain phenomenon lowers the display quality and contrast of the liquid crystal.

An object of the present invention is to manufacture and configure a liquid crystal display device capable of preventing defects such as disconnection of a data bus line and signal delay of a gate bus line as described above, preventing a domain phenomenon and realizing a high aperture ratio.

[Table 1a]

For this purpose, an organic insulating film having a relative dielectric constant of 3.0 or less, that is, benzocyclobutene (BCB), F-doped parerine, etc., as shown in Table 1a, and a PFCB Perfouorocyclobutane) or the like is used.

These organic materials can react to light depending on the structure of additives or similar organic materials.

The organic insulating film has good line step characteristics and can prevent a line step from occurring at the intersection of the gate bus line 18 and the data bus line 19 or the like and can be formed on the data bus line 19 A domain phenomenon does not occur even if a pixel electrode is formed, and a high aperture ratio can be realized.

As an embodiment of the present invention, a method of manufacturing a liquid crystal display device having an IOP (ITO on passivation) structure includes an organic insulating film having a relative dielectric constant of 3.0 or less, that is, benzocyclobutene (BCB) A step of forming a gate insulating film and a protective film using PFCB (Perfluorocyclobutane) or the like not mentioned in Table 1a, and a step of forming the pixel electrode on the protective film so as to selectively overlap the gate bus line and the data bus line .

A gate insulating film formed on the substrate on which the gate electrode is formed, the gate insulating film being made of an organic insulating film having a relative dielectric constant of 3.0 or less; A source electrode and a drain electrode branched from the data bus line on the ohmic contact layer, and a source electrode and a drain electrode formed on the substrate on which the source / drain electrode is formed. A protective film made of an organic insulating film having a relative dielectric constant of 3.0 or less; a contact hole formed in a portion of the drain electrode through the protective film; a gate electrode contacted with the drain electrode through the contact hole and selectively overlapped with the gate bus line and the data bus line And the pixel electrode formed on the passivation layer.

Hereinafter, a manufacturing process of a liquid crystal display device will be described in detail with reference to an example of a BCB including Si-O bond structure among organic insulating films having a relative dielectric constant of 3.0 or less.

[Example 1]

Embodiment 1 of the present invention will be described with reference to a process sectional view of FIG. 6 applying VI-VI of FIG. 5.

A metal film, for example, Al, AlTa, or a Cr metal film is deposited on the transparent substrate 11 and then patterned to form the gate bus line 18 and the gate electrode 18a branched from the gate bus line 18 .

Subsequently, an anodic oxidation is performed by anodizing the predetermined portion in order to improve the insulating property and prevent hillocks (FIG. 6 (a)).

After the above process, a benzocyclobutene (BCB) layer, which is an organic insulating film to be the gate insulating film 23, is applied, and an a-Si layer and an n + a-Si layer, which become the semiconductor layer 22, Thereby forming a layer 25 (Fig. 6 (b)).

The gate insulating film 23 may be formed by laminating films of SiNx, SiOx, etc., which are inorganic insulating films, on a benzocyclobutene film as an organic insulating film.

The reason for stacking the inorganic insulating film on the organic insulating film as described above is to prevent peeling of the laminated film when the organic insulating film has poor adhesion to the semiconductor layer, the metal layer, and the ITO film.

After the above process, the ohmic contact layer 25 and the semiconductor layer 22 are formed by patterning (FIG. 6 (c)).

Although the semiconductor layer is formed in an island shape in the above-described FIG. 6 (c), a semiconductor layer may be formed in a region of a data bus line formed in a subsequent process.

Subsequently, a metal film (for example, a single metal film of Cr, Tr, Mo or the like or a two-layer structure of a second metal layer such as Al on a single metal layer) is deposited by sputtering or the like and then patterned to form a data bus line 19 and a source electrode 19a and a drain electrode 19b branched from the data bus line 19 are formed and then the source / drain electrodes 19a and 19b are used as a mask to form the ohmic contact layer 25 ) Are separated by a method such as etching (see FIG. 6 (d)).

Subsequently, a benzocyclobutene (BCB) layer, which is an organic insulating film to be a protective film 26, is deposited, and a contact hole 31 is formed in the drain electrode 19b (FIG.

As described above, the protective film 26 may be formed by laminating at least one layer of an inorganic insulating film such as SiNx or SiOx film on or under the BCB film as the organic insulating film to improve the adhesion to the ITO film or the film constituting the source / .

Subsequently, an ITO film is deposited by sputtering or the like and then patterned to form a pixel electrode 15 (FIG. 6 (f)).

Although the pixel electrode 15 is superposed only on the data bus line 19 in the plan view of the liquid crystal display of the present invention, the pixel electrode 15 is selectively overlapped with other portions, that is, the gate bus line 18 and the TFT portion The aperture ratio can be maximized.

[Example 2]

Embodiment 2 of the present invention will be described with reference to a process sectional view of FIG. 7 applying line VII-VII of FIG. 5.

A metal film, for example, a Cr (Cr) film is deposited on the transparent substrate 11 and then patterned to form a gate electrode 18a and a gate electrode 18a branched at the gate bus line 18.

Subsequently, anodic oxidation is performed to improve insulation and prevent hillocks (Fig. 7 (a)).

After the above process, a benzocyclobutene (BCB) 23a layer serving as an organic insulating film to be the gate insulating film 23 is applied, and at least one layer of SiNx, SiOx layer, etc., which is the inorganic insulating film 23b, b) Fig.

The reason for stacking the inorganic insulating film on the organic insulating film as described above is to prevent the laminated film from being peeled off when the organic insulating film has poor adhesion to the semiconductor layer or the metal layer or the like.

Then, an a-Si layer to be a semiconductor layer 22 and an SiNx film to be an etch stopper layer 35 are continuously deposited, and the SiOx film is patterned to form an etch stopper layer 35 (see (c) Degree).

Then, an n + -type a-Si layer to be an ohmic contact layer 25 is deposited or ion doped and then patterned to form the semiconductor layer 22 and the ohmic contact layer 25 (FIG. 7 (d)).

A data bus line 19 functioning as a signal line, a source electrode 19a and a drain electrode 19b branched from the data bus line 19 are formed by depositing a metal film, for example, a Cr metal film by sputtering or the like, And the ohmic contact layer 25 exposed by using the source / drain electrode as a mask is separated into two by etching or the like (FIG. 7 (e)).

Then, a benzocyclobutene (BCB) layer, which is an organic insulating film to be a protective film 26, is applied, and a contact hole 31 is formed in the drain electrode 19b (FIG.

Subsequently, an ITO film, which is a transparent conductive film, is deposited by sputtering or the like and then patterned to form a pixel electrode 15 (FIG. 7 (g)).

As described above, the protective film 26 may be formed by stacking at least one layer of an inorganic insulating film such as SiNx, SiOx film, etc. on the benzocyclobutene film, which is an organic insulating film, to improve the adhesion to the ITO film.

In order to improve the adhesion to the film forming the source / drain electrodes, at least one or more inorganic insulating films such as SiNx and SiOx may be stacked before applying the BCB, which is an organic insulating film.

An organic insulating film having a specific dielectric constant of 3.0 or less can be applied to a stagger type TFT shown in FIG. 9 (a) or a coplanar type TFT shown in FIG. 8 (b).

Although the pixel electrode 15 is superposed only on the data bus line 19 in the plan view of the liquid crystal display of the present invention, the pixel electrode 15 is selectively overlapped with other portions, that is, the gate bus line 18 and the TFT portion The aperture ratio can be maximized.

Although the present invention has been described in connection with the IOP structure in which the pixel electrode is formed on the protective film, the present invention is applicable regardless of the position where the pixel electrode is formed.

For example

First, the gate electrode and the pixel electrode may be formed on the same layer.

Secondly, the pixel electrode may be formed before or after the semiconductor layer and the ohmic contact layer are formed.

The common electrode may be formed on the same substrate on which the pixel electrode is formed, and the common electrode may be formed on the substrate opposite to the substrate on which the pixel electrode is formed.

That is, the IPS (In-Plane Switching) mode is advantageous in realizing a wide viewing angle, because the common electrode and the pixel electrode are formed on the same substrate.

The effect of the liquid crystal display device manufactured and configured according to the above embodiments is characterized by using benzocyclobutene (BCB) or the like, which is an organic insulating film having a good line step property as the gate insulating film 23 and the protective film 26 It is possible to prevent a line step from occurring at the intersection between the gate bus line 18 and the data bus line 19 or the like (FIG. 8). In order to increase the aperture ratio, the pixel bus line 19, A domain phenomenon does not occur even if the electrode 15 is formed, and thus a liquid crystal display device with a high aperture ratio can be realized.

Claims (24)

A manufacturing method of a liquid crystal display device including a substrate, a gate electrode branching at a gate bus line, a gate insulating film, a semiconductor layer, an ohmic contact layer, and a data bus line includes a source electrode and a drain electrode and a protective film, Wherein the organic insulating film is made of any one selected from the group consisting of benzocyclobutene (BCB), Teflon, cytochrome, fluorinated polyarylether, and F-doped pareiline, which is an organic insulating film having a dielectric constant of 1.0 to 3.0. The method of claim 1, further comprising: Further comprising the step of forming a pixel electrode on the protective film so as to selectively overlap the data bus line. The method of claim 1, further comprising forming a pixel electrode on the passivation layer so as to selectively overlap the gate bus line and the data bus line adjacent to the gate bus line. The method of claim 1, further comprising: And forming a pixel electrode on the same layer as the gate electrode. The method of claim 1, further comprising: And a step of forming a pixel electrode before or after forming the semiconductor layer The method of claim 1, further comprising: And an etch stopper layer is further formed between the semiconductor layer and the ohmic contact layer. The liquid crystal display device according to claim 1, wherein the gate insulating film is formed by stacking an organic insulating film and at least one or more inorganic insulating films. The method of claim 1, further comprising: Wherein the protective film is formed by stacking an organic insulating film and at least one or more inorganic insulating films 3. The method of claim 2, And forming a common electrode on the same substrate as the pixel electrode. 3. The method of claim 2, And a step of forming a common electrode on a substrate facing the pixel electrode 8. The method of manufacturing a liquid crystal display device according to claim 7, wherein the gate insulating film is formed by stacking an organic insulating film and at least one or more inorganic insulating films. The method of claim 1, wherein the protective layer comprises a photosensitive organic material. A liquid crystal display comprising a substrate, a gate electrode branched from the gate bus line, a gate insulating film, a semiconductor layer, an ohmic contact layer, and a data bus line, wherein the protective film has a source electrode and a drain electrode, wherein the protective film has a relative dielectric constant of 1.0 Wherein the organic insulating film is made of any one selected from the group consisting of benzocyclobutene (BCB), Teflon, cytochrome, fluorinated polyarylether, and F-doped parylene. 14. The method of claim 13, And a pixel electrode is formed on the protective film so as to selectively overlap the data bus line. 14. The liquid crystal display of claim 13, wherein a pixel electrode is formed on the passivation layer so as to selectively overlap adjacent gate bus lines and data bus lines of the gate bus line. 14. The method of claim 13, And a pixel electrode is formed on the same layer as the gate electrode. 14. The method of claim 13, And a pixel electrode is formed before or after the semiconductor layer is formed. 14. The method of claim 13, And an etch stopper layer is formed between the semiconductor layer and the ohmic contact layer. 14. The liquid crystal display device according to claim 13, wherein the gate insulating film is formed by stacking an organic insulating film and at least one or more inorganic insulating films. 14. The method of claim 13, Wherein the protective film is formed so that an organic insulating film and at least one or more inorganic insulating films are laminated. 15. The method of claim 14, wherein: And a common electrode is formed on the same substrate as the pixel electrode. The liquid crystal display device according to claim 14, wherein a common electrode is formed on a substrate facing the pixel electrode. 20. The liquid crystal display device according to claim 19, wherein the protective film is formed by stacking an organic insulating film and at least one or more inorganic insulating films. 14. The liquid crystal display device according to claim 13, wherein the protective film comprises a photosensitive organic material.