KR980010548A - Method for manufacturing active matrix liquid crystal display device and active matrix liquid crystal display device - Google Patents

Abstract

A method of manufacturing an active matrix liquid crystal display device according to the present invention includes the steps of forming a gate electrode branched on a gate bus line on a transparent substrate; forming a gate insulating film (23) as an organic insulating film; A step of forming a semiconductor layer on the gate insulating film of the gate electrode portion by performing a plasma interface treatment with a gas containing N, a gas containing F, or the like; a step of forming a source / drain branching in the data bus line 15 Forming a protective film 26 with an organic insulating film after forming a source / drain electrode, plasma-treating the surface of the exposed semiconductor layer with a gas containing N 2, N, or a gas containing F, , And thus the stable characteristics of the switching device are maintained. In addition, Acti, which realizes high aperture ratio without deteriorating image quality and contrast, To provide a matrix liquid crystal display device.

Description

Method for manufacturing active matrix liquid crystal display device and active matrix liquid crystal display device

FIG. 1 is a perspective view of a basic structure showing a part of a general active matrix liquid crystal display device. FIG.

FIG. 2 is a plan view of a part of a conventional active matrix liquid crystal display; FIG.

3 is a cross-sectional view of a first substrate 3 of a conventional active matrix liquid crystal display device in which a line III-III in FIG. 2 is cut.

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 a part of an active matrix liquid crystal display device of the present invention. FIG.

6 is a cross-sectional view showing a manufacturing process of the first substrate 3 of the active matrix liquid crystal display device of the present invention in which the line VI-VI of FIG.

Figs. 8, 9 and 10 are cross-sectional views of the first substrate 3 of the active matrix liquid crystal display device to which the present invention is applicable

DESCRIPTION OF THE REFERENCE NUMERALS

(1): Polarizing plate (22): Semiconductor layer

(2): second substrate (25): ohmic contact layer

(3): first substrate (26): protective film

(4): pixel electrode (40): liquid crystal

(15a): source electrode (8): TFT

(15): data bus line (15b): drain electrode

(17a): gate electrode (17): gate bus line

(11), (11 '): transparent substrate 23: gate insulating film

(35): anodic oxide film (31): contact hole

(36a): gas plasma-treated interface of the BCB film

(36b): a gas plasma-treated interface of the semiconductor layer

The present invention relates to a manufacturing method of an active matrix liquid crystal display device including a thin film transistor (hereinafter referred to as a TFT) and a structure of an active matrix liquid crystal display device manufactured by the manufacturing method, and more particularly, will be.

As shown in FIG. 1, which is a basic structural view showing a part of a general active matrix liquid crystal display device, a liquid crystal display device has a substrate on which a plurality of pixels are arranged in a matrix (hereinafter referred to as a first substrate).

Each of the pixel electrodes 4 of the liquid crystal display part of the first substrate 3 is disposed at a portion where two adjacent gate bus lines 17 and two adjacent data bus lines 15 are formed to cross each other.

The gate bus line 17 is formed in a horizontal direction and a plurality of gate electrodes (not shown) branched from the gate bus line 17 are formed in the longitudinal direction.

On the other hand, the data bus line 15 is formed in a longitudinal direction and a plurality of source electrodes (not shown) branched from the data bus line 15 are formed in the horizontal direction.

A TFT 8 is formed at a portion where the gate bus line 17 and the data bus line 15 intersect and the TFT 8 is formed to be in electrical contact with the pixel electrode 4. [

On the other hand, the liquid crystal display device has a substrate on which a color filter layer 38 and a common electrode 37 are formed (hereinafter referred to as a second substrate). The first substrate 3 and the second substrate 2 are opposed to each other and the liquid crystal 40 is filled between the two substrates.

A polarizing plate 1 is formed on the first substrate 3 and the second substrate 2, respectively.

(11) and (11 '), which are not described in FIG. 1, are transparent substrates.

The above-described various components are combined to complete an active matrix liquid crystal display device.

A method of manufacturing the first substrate 3, which is related to the object of the present invention, will be described in detail with reference to the drawings.

2 is a partial plan view of a conventional active matrix liquid crystal display device.

FIG. 3 is a cross-sectional view of the first substrate 3 cut along the line III-III in FIG. 2.

As shown in FIG. 3, the structure of the first substrate 3 of the active matrix liquid crystal display device manufactured by the conventional manufacturing method is as follows.

A gate bus line 17 formed in a lateral direction on the transparent substrate 11 and a gate electrode 17a branched in the longitudinal direction in the gate bus line 17 are formed.

The gate electrode 17a 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 17a 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 17a.

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

The source bus line 15 formed in the longitudinal direction and the source bus line 15 are laterally branched to form the source electrode 15a and the drain electrode 15b is formed at a predetermined distance from the source electrode 15a .

The source electrode 15a and the drain electrode 15b 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 and drain electrodes and the like and a transparent conductive film ITO (Indium Tin Oxide) film is formed on the protective film 26 to constitute the pixel electrode 4.

However, the manufacturing method of the active matrix liquid crystal display device in which the first substrate 3 is manufactured by the conventional manufacturing method as described above

First, since the data bus line 15 rides the gate bus line 17 along the line step as it is at the intersection portion with the gate bus line 17 as shown in FIG. 4, the step of the data bus line 15 There is a possibility that the data bus line is disconnected or the data bus line 15 is short-circuited with the gate bus line 17

Secondly, in order to realize a high aperture ratio in the conventional manufacturing method, the pixel electrode 4 formed on the protective film 26 made of an inorganic film such as SiNx or SiOx is formed on the gate bus line 17 and the data bus line 15, the picture quality and contrast of the pixel are lowered at a portion where the pixel electrode 4 overlaps with the gate bus line 17 and the data bus line 15.

The lowering of the image quality and the contrast is caused by forming a protective film 26 made of an inorganic film such as SiNx or SiOx and superimposing the pixel electrode on the protective film 26 on the gate bus line 17 and the data bus line 15 The alignment state of the liquid crystal molecules in the stepped portion becomes different due to the rubbing of the step portion between the gate bus line 17 and the data bus line 15 in the subsequent rubbing of the alignment film.

The problem of the above conventional method of manufacturing a liquid crystal display device, that is, the problem of rubbing defects, short defects and aperture ratio of the alignment film can be solved to some extent by constructing the gate insulating film 23 and the protective film 26 as organic insulating films.

However, by using the organic insulating film, a charge trap of charge is generated at the interface portion between the semiconductor layer 22 of the TFT and the organic insulating film, so that the ON characteristic of the TFT is shifted by a predetermined amount, There is a falling problem.

In addition, since the organic insulating film has weak bonding force with other materials such as metal, ITO film, etc., many defects occur when depositing or patterning other materials on the organic insulating film. An object of the present invention is to prevent a data bus line from being disconnected at the intersection portion of the gate bus line 17 and the data bus line 15 or the like and prevent shorting between the data bus line 15 and the gate bus line 17, And an object of the present invention is to provide a liquid crystal display device having an aperture ratio, in particular, a switching element such as a TFT having stable characteristics.

In order to achieve the above object, the active matrix liquid crystal display device of the present invention may be formed by forming the gate insulating film 23 as an organic insulating film, performing a plasma interface treatment with a gas containing N 2, N, Forming a source / drain electrode that branches off from the data bus line 15 so as to be in contact with the semiconductor layer, and forming a source / drain electrode on the exposed semiconductor layer surface with a gas containing N 2, N And F, and then forming a protective film 26 with an organic insulating film to constitute the first substrate 3. [0034]

Benzocyclobutene (BCB), F-doped barerine, and PFCB (Perfluorocyclobutane) not mentioned in Table 1-1 are used as the organic insulating film.

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

Since the organic insulating film has a leveling property exceeding a level difference, the surface of the substrate of the liquid crystal display device can be planarized, and the defective orientation of the liquid crystal due to the level difference can be reduced. Further, since the organic insulating film has a lower dielectric constant than the inorganic insulating film, A pixel electrode is formed on an organic insulating film so as to overlap with a line such as a data bus line, thereby forming a liquid crystal display device having a high aperture ratio, and voltage distortion due to the generation of parasitic capacitance occurs at a portion where the line overlaps with the pixel electrode It is possible to provide a liquid crystal display device in which defects such as screen flickering do not occur.

If the organic insulating film is used as the gate insulating film 23, there is no step of the film, so that the defect that the data bus line 17 is disconnected or short-circuited at the intersection of the gate bus line 15 and the data bus line 17 There is an advantage not to occur.

Hereinafter, a method for manufacturing a first substrate of an active matrix liquid crystal display device will be described in detail with reference to a BCB including a Si-O bond structure among organic insulating films having a dielectric constant of 3.0 or less in the embodiments of the present invention.

Example 1

Embodiment 1 of the present invention describes a manufacturing method of an active matrix liquid crystal display device according to a process sectional view of FIG. 6, which is a sectional view taken along line VI-VI of FIG. 5 which is a plan view of an active matrix liquid crystal display device of the present invention.

(A1, A1Ta, A1Mo, Ta, Ti) or Cr metal which does not cause anodic oxidation is deposited on the transparent tube 11, a photoresist is coated on the metal film, And the metal film is etched by wet etching or the like according to the developed pattern to form a gate electrode 17a which branches off from the gate bus line and the gate bus line (FIG. 6A).

The photoresist remaining on the substrate is removed by a separate process.

Subsequently, in the case where the metal film is an anodic oxidizable metal, an anodic oxide film 35 is formed on the gate bus line 17 and the gate electrode 17a (FIG. 6B) in order to improve insulation and prevent hillocks.

Subsequently to the above step, a BCB serving as a gate insulating film 23 is applied, and the BCB surface is treated with a gas containing N 2, N, F, or the like at a plasma interface 36a (FIG.

The gate insulating film 23 is formed of an organic insulating film including a bonding structure of Si and O and the surface is subjected to a surface treatment to form a Si-N (silicon nitride) or Si-F (silicon fluoride) The charge trap of charge is not generated between the semiconductor layer and the organic insulating film, and the characteristics of the TFT can be stabilized.

Also, when a conventional inorganic insulating film is used, disconnection or short failure of the data bus line 15 occurring at the intersection of the gate bus line 17 and the data bus line 15 is eliminated.

Next, an a-Si layer to be a semiconductor layer 22 and an n + type a-Si layer to be an ohmic contact layer 25 are successively deposited, and then a photoresist is coated on the n + type a-Si layer, Si layer and the a-Si layer are simultaneously etched according to the developed pattern to form the ohmic contact layer 25 and the semiconductor layer 22 (see FIG. 6D) .

The photoresist remaining on the substrate is removed by a separate process.

Then, an A1 metal film or the like is deposited on the entire surface of the substrate by sputtering, a photoresist is coated on the metal film, the photoresist is developed so as to have a predetermined pattern, and the metal film is etched according to the developed pattern, A source electrode 15a branched at the data bus line 15 and a drain electrode 15b serving as an output terminal are formed. Subsequently, the center portion of the ohmic contact layer 25 is etched using the source electrode and the drain electrode as masks (FIG. 6E) so that the ohmic contact layer 25 is separated on both sides.

Then, the surface of the semiconductor layer exposed by the etching of the central portion of the ohmic contact layer 25 is treated with a gas containing N 2, N, a gas containing F, or the like at a plasma interface 36 b, BCB is applied (Fig. 6F).

When the interface 36a or 36b is treated with a gas containing N2 or N or a gas containing F or the like on the surface of the organic insulating film to be the gate insulating film 23 or the surface of the exposed semiconductor layer as described above, A charge trap of charge is not generated at the interface of the semiconductor layer 22 to increase the bonding energy of the interfacial interface and not only the TFT is stabilized but also other materials such as metal, An ITO film, an a-Si layer, or the like is deposited or patterned, the peeling of the film and the defective patterning do not occur.

Therefore, the data bus line 15 is formed at the intersection of the gate bus line 17 and the data bus line 15 by using the organic insulating film as the gate insulating film 23 and the protective film 26, The data bus line 15 and the gate bus line 17 are not short-circuited, and a high aperture ratio can be obtained. In particular, a switching element such as a TFT can have stable characteristics.

Subsequently, a photoresist is coated on the protective film 26 made of the organic insulating film, the photoresist is developed to have a predetermined pattern, and the protective film 26 is etched according to the developed pattern to form a contact hole 31) (see Fig. 6G).

The photoresist remaining on the substrate is removed by a separate process.

Subsequently, an ITO (Indium Tin Oxide) film is deposited on the protective film 26 on which the contact hole is formed by stuttering, a photoresist is coated on the ITO film, the photoresist is developed to have a predetermined pattern, The ITO film is etched according to the pattern to form the pixel electrode 4 so as to overlap the data bus line as shown in FIG. 5 (FIG. 6H).

The photoresist remaining on the substrate is removed by a separate process.

Although the pixel electrode 4 is superimposed on only the data bus line 15 in the fifth drawing showing a partial plan view of the active matrix liquid crystal display device of the present invention, the other part, that is, the gate bus line 17 and the TFT part, It is possible to maximize the aperture ratio.

Generally, the portion of the pixel electrode overlapped with the gate bus line 17 becomes a storage capacitor electrode, but a description of the formation process of the storage capacitor electrode is omitted.

The present invention is applicable regardless of the position where the pixel electrode is formed on the protective film.

For example, a pixel electrode may be formed before or after the semiconductor layer-ohmic contact layer is formed (FIG. 7).

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.

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

Also, the present invention can be applied to a liquid crystal display device in which the first substrate has the structure of FIG. 8, FIG. 9, and FIG. 10.

Claims (20)

A switching element having a gate electrode, a gate insulating film, a semiconductor layer partially exposed on the surface, an ohmic contact layer, and source / drain electrodes branched from the data bus line; And a protective film covering the switching element, the method comprising the steps of: A step of forming the gate insulating film as an organic insulating film, a step of interfacial processing the surface of the organic insulating film, a step of interfacial processing the exposed semiconductor layer surface of the switching element, And forming a protective film covering the interfacial processed switching element as an organic insulating film. The method of claim 1, further comprising: Wherein the surface of the gate insulating film and the exposed surface of the semiconductor layer of the switching element are exposed to a gas plasma so as to be subjected to interfacial processing. 3. The method of claim 2, Wherein the gas plasma is one selected from the group consisting of N 2, N-containing gas, and F-containing gas. 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: Further comprising forming a pixel electrode on the protective film so as to selectively overlap the gate bus line adjacent to the gate bus line and the data bus line. The method of claim 1, further comprising: Wherein a step of forming a pixel electrode after forming the semiconductor layer is further added. The method of claim 1, further comprising: Wherein a step of forming a pixel electrode before forming the semiconductor layer is further added. 8. The method according to any one of claims 1 to 7, Wherein the organic insulating layer includes a Si-O bond structure. 8. The method according to any one of claims 1 to 7, Wherein the organic insulating film has a dielectric constant of 3.0 or less. 8. The compound according to any one of claims 1 to 7, wherein < RTI ID = 0.0 > Wherein the organic insulating layer is one selected from BCB and PFCB. A switching element having a gate electrode, a gate insulating film, a semiconductor layer partially exposed on the surface, an ohmic contact layer, and source / drain electrodes branched from the data bus line; And a protective layer covering the switching element, the liquid crystal display comprising: Wherein the gate insulating film is formed of an organic insulating film, the surface of the organic insulating film is interfacial processed, the exposed semiconductor layer surface of the switching element is interfacial processed, and the protective film is formed of an organic insulating film. 12. The method of claim 11, further comprising: Wherein the surface of the gate insulating film and the exposed surface of the semiconductor layer of the switching element are exposed to a gas plasma and subjected to an interface treatment. The method as claimed in claim 12, Wherein the gas plasma uses any one selected from the group consisting of N 2, N-containing gas, and F-containing gas. 12. The method of claim 11, further comprising: And the pixel electrode is further formed on the protective film so as to selectively overlap the data bus line. 12. The method of claim 11, further comprising: And the pixel electrode is further formed on the passivation layer so as to selectively overlap the gate bus line adjacent to the gate bus line and the data bus line. 12. The method of claim 11, further comprising: And the pixel electrode is further formed after forming the semiconductor layer. 12. The method of claim 11, further comprising: And the pixel electrode is further formed before forming the semiconductor layer. 18. The method according to any one of claims 11 to 17, Wherein the organic insulating film includes a Si-O laminated structure. 18. The method according to any one of claims 11 to 17, Wherein the organic insulating film has a dielectric constant of 3.0 or less. 18. The method according to any one of claims 11 to 17, Wherein the organic insulating film is any one selected from BCB and PFCB. ※ Note: It is disclosed by the contents of the first application.