KR101725993B1 - Method for fabricating liquid crystal display device - Google Patents

Abstract

The present invention discloses a method of manufacturing a transverse electric field type liquid crystal display device. A method of manufacturing a transverse electric field type liquid crystal display device according to the present invention comprises sequentially forming a transparent conductive layer and a metal film on a substrate and then performing a mask process to form a gate wiring having a laminated structure of a transparent conductive layer and a metal film, A second pixel electrode pattern branched from the first pixel electrode, a first common electrode pattern of a rectangular structure in which a pixel region is opened, a first common electrode pattern of a square structure in which a pixel region is opened, Forming a second common electrode pattern alternately arranged with the gate electrode, a gate pad extended from the gate wiring, and a data pad; forming a gate insulating film, an amorphous silicon film, and a doped amorphous silicon film sequentially Then, a mask process is performed to form an active layer on the gate wiring, a step in which the active layer is formed A source / drain electrode, a data line parallel to the second pixel electrode pattern and parallel to the second common electrode pattern and connected to the data pad, intersecting the source / drain electrode and the common wiring, Forming a gate pad pattern and a data pad pattern, forming a protective film on the substrate on which the source / drain electrodes are formed, and then removing the gate insulating film and the protective film formed on the pixel region using a diffraction mask or a halftone mask, Exposing the electrode pattern, the first common electrode pattern, and the second common electrode pattern, and sequentially etching the transparent conductive layer and the metal film to the exposed pixel region to sequentially form a transparent conductive layer Forming a first common electrode, a second common electrode, and a second pixel electrode, Cross wiring and data wiring are defined as crossing.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for fabricating a liquid crystal display device,

The present invention relates to a method for manufacturing a liquid crystal display device.

The liquid crystal display device has been attracting attention as an alternative means to overcome the disadvantages of the CRT (Cathode-Ray Tube) due to its advantages such as miniaturization, light weight and low power consumption. Currently, almost all the information And is mounted on a processing apparatus.

Such a liquid crystal display device generally applies a voltage to a specific molecular arrangement of a liquid crystal to convert it into another molecular array to convert a change in optical property into a visual change, and is a display device using modulation of light by a liquid crystal cell.

The liquid crystal display device has a manufacturing process of a panel upper substrate and a lower substrate accompanied by a process of forming a liquid crystal cell constituting a pixel unit, an alignment film formation and a rubbing process for alignment of liquid crystal, And a process of injecting and sealing the liquid crystal between the upper substrate and the lower substrate, and the like.

In the lower substrate manufacturing process, a plurality of gate wirings and data wirings are cross-arrayed to define a unit pixel region. In each pixel region, a thin film transistor (hereinafter referred to as a TFT) and a pixel electrode Pixel electrode. The thin film transistor is turned on by a driving signal supplied through a gate wiring and performs a switching function of supplying a graphic signal supplied from the data wiring to a pixel electrode. The graphic signal thus supplied to the pixel electrode generates an electric field for rotating the liquid crystal to modulate external light or internal light to display an image.

The liquid crystal display device as described above is a twisted nematic (TN) type liquid crystal display device that drives nematic liquid crystal molecules in a direction perpendicular to the substrate. The liquid crystal display device of this type has a viewing angle of 90 degrees As shown in Fig.

This is because of the refractive anisotropy of the liquid crystal molecules, and liquid crystal molecules aligned horizontally with the substrate are oriented in a direction substantially perpendicular to the substrate when a voltage is applied to the liquid crystal display panel.

An IPS (In Plane Switching) liquid crystal display device has been developed in which a liquid crystal molecule is driven in a horizontal direction with respect to a substrate to improve a viewing angle to 170 degrees or more.

The transverse electric field type liquid crystal display device has a structure in which pixel electrodes and common electrodes are arranged on a lower substrate of a liquid crystal display device. Particularly, since the transverse electric field type liquid crystal display device uses either a pixel electrode or a common electrode as an opaque metal, the aperture ratio is low.

In order for the liquid crystal display device to have a high aperture ratio and a high transmittance characteristic, it is preferable to narrow the widths of the gate wirings, the data wirings, the pixel electrodes, and the common electrodes arranged in the predetermined pixel region.

However, it is difficult to reduce the wiring width or the electrode width to be patterned to a certain width or less due to the physical characteristics of the exposure apparatus used in the liquid crystal display manufacturing method. This is due to the limitations of the mask and the exposure system used in the LCD manufacturing process.

The present invention provides a method of manufacturing a liquid crystal display device capable of forming a wiring or an electrode width much narrower than a physical resolution of a mask and an exposure apparatus used in a liquid crystal display device manufacturing process.

It is another object of the present invention to provide a method of manufacturing a liquid crystal display device in which signal wirings and electrode widths formed in pixel regions of a liquid crystal display device are formed in fine patterns to increase the pixel aperture ratio and transmittance.

According to an aspect of the present invention, there is provided a method of manufacturing a transverse electric field type liquid crystal display device, comprising: sequentially forming a transparent conductive layer and a metal film on a substrate and then performing a mask process to form a laminated structure of a transparent conductive layer and a metal film A second pixel electrode pattern branched from the first pixel electrode, a first common electrode pattern of a square structure in which a pixel region is opened, a second common electrode pattern of a pixel region A step of forming a gate pad and a data pad extending from the gate wiring, a step of forming a gate insulating film, an amorphous silicon film, and a doping film The amorphous silicon film is sequentially formed, and then the mask process is performed to form an active layer on the gate wiring Drain metal film is formed on the substrate on which the active layer is formed, and then the mask process is performed to form source / drain electrodes, data lines parallel to the second common electrode pattern, intersecting with the common wiring, Forming a data line, a gate pad pattern and a data pad pattern connected to the pad, forming a protective film on the substrate on which the source / drain electrode is formed, and then forming a gate insulating film and a protective film on the pixel region using a diffraction mask or a half- Exposing the second pixel electrode pattern, the first common electrode pattern, and the second common electrode pattern, and sequentially performing an etching process for the transparent conductive layer and an etching process for the metal film in the exposed pixel region, Forming a first common electrode, a second common electrode, and a second pixel electrode including a transparent conductive layer in a region And the pixel region is defined by intersecting the gate wiring and the data wiring.

The method of manufacturing a liquid crystal display device of the present invention has the effect of forming wirings and electrodes with a much narrower width by using a conventional mask and an exposure apparatus.

In addition, the method of manufacturing a liquid crystal display of the present invention has the effect of realizing a high aperture ratio and a high transmittance liquid crystal display device by forming a signal line and an electrode width in a fine pattern in a pixel region without adding equipment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

1 is a plan view showing a pixel structure of a liquid crystal display device according to the present invention.

Referring to FIG. 1, a gate line 101 and a data line 103 intersect to define a pixel region, and a TFT serving as a switching element is disposed in the intersection region.

In the pixel region, a common wiring 104 parallel to the gate wiring 101 is disposed in a region adjacent to the gate wiring 101. [ The common wiring 104 intersects with the data wiring 103.

Further, a first common electrode 114 branched from the common wiring 104 is formed integrally along both side edges of the pixel region. The first common electrode 114 has a square structure in which a pixel region is opened.

A second common electrode 124 is formed in the center of the pixel region in a direction parallel to the data line 103.

In the pixel region, a first pixel electrode 109 is formed in a direction parallel to the common wiring 104. A second pixel electrode 109a is formed in a direction parallel to the data line 103 from the first pixel electrode 109. [ The second pixel electrode 109a is disposed alternately with the second common electrode 124. [

The first pixel electrode 109 and the second pixel electrode 109a are integrally formed, and the first pixel electrode 109 is electrically connected to the drain electrode of the TFT.

In the pad region, a gate pad 110 is formed extending from the gate wiring 101, and a gate pad electrode 140 is formed on the gate pad 110.

The data pad 103a extends from the data line 103 and the data pad electrode 130 is formed on the data pad 103a.

In the present invention, the pixel electrodes and the common electrodes are exposed to the first and second etching processes, and are formed to be narrower than electrode widths that can be realized by a mask or an exposure apparatus. In the present invention, the widths of the common electrode and the pixel electrode can be reduced to 2 mu m or less, and the aperture ratio and transmittance of the pixel region are improved.

2A to 2E show a manufacturing process of a liquid crystal display device according to the present invention.

2A to 2E, a transparent conductive material (ITO, ITZO, IZO) and a metal film are sequentially formed on a transparent insulating substrate 100. Thereafter, the mask process is performed to form the gate wiring 101, the common wiring 104, the first pixel electrode 109, the second pixel electrode pattern 19, the first common electrode pattern 14, The gate pad 110, and the data pad 130 are simultaneously formed.

The metal film may be formed of at least one metal film using a material such as Cu, MoTi, Al, or Ag.

The first common electrode pattern 14, the second common electrode pattern 24, and the gate pad 103 are formed on the gate wiring 101, the common wiring 104, the first pixel electrode 109, the pixel electrode pattern 19, the first common electrode pattern 14, (110) and the data pad (130) are formed of two or more metal layers including a metal layer made of a transparent conductive material.

The first common electrode pattern 14, the second common electrode pattern 24, the gate electrode 102, the common wiring 104, the first pixel electrode 109, the second pixel electrode pattern 19, the first common electrode pattern 14, The method of forming the data pad 110 and the data pad 130 includes a method of etching the metal film on the transparent conductive layer and then etching the transparent conductive layer on the bottom using the etched metal film as a mask.

That is, in the first mask process, the wet etching process for the metal film and the wet etching process for the transparent conductive layer proceed sequentially.

The transparent conductive layer under the metal film is etched in an undercut shape due to the difference in etch ratio between the metal film and the transparent conductive layer. That is, the transparent conductive layer is etched to the inside of both side edges of the metal film to be etched. Refer to Figs. 3A to 3D for a specific explanation.

2B, when the gate wiring 101 is formed on the insulating substrate 100, the gate insulating film 102, the amorphous silicon film, and the doped (p + or n +) amorphous silicon film are sequentially formed Then, a mask process is performed to form an active layer 116 on the gate wiring 101 serving as a gate electrode.

The active layer 116 is formed with a contact hole for exposing a portion of the first pixel electrode 109, the gate pad 110, and the data pad 130 using a diffraction mask or a halftone mask.

That is, in the second mask process using the diffraction mask or the half-tone mask, a part of the first pixel electrode 109, the gate pad 110, and the data pad 130 are exposed using the photoresist film formed as the halftone pattern as a mask do. Thereafter, an ashing process is performed, and then the active layer 116 is formed.

Next, as shown in FIG. 2C, a source / drain metal film is formed on the insulating substrate 100 on which the active layer 116 is formed, and then the mask process is performed to form the source / drain electrodes 117a and 117b, A wiring pattern 103, a gate pad pattern 140a and a data pad pattern 130a are formed.

The source / drain metal film may be formed of a bilayer metal film such as Cu / MoTi. Further, it can be formed of a transparent conductive layer (ITO, ITZO, IZO) resistant to corrosiveness and a double-layer metal film made of a metal layer such as Cu, Al, or Mo.

When the source / drain electrodes 117a and 117b are formed as described above, a protective film 108 is formed on the insulating substrate 100, as shown in FIGS. 2D and 2E. When the protective layer 108 is formed, a photoresist layer 200 is formed, and then the gate insulating layer 102 and the protective layer 108 are removed using a diffraction mask or a halftone mask.

Accordingly, the second pixel electrode pattern 19, the first common electrode pattern 14, and the second common electrode pattern 24 are exposed to the outside in the pixel region. A second etching process is performed on the lower transparent conductive layer of the second pixel electrode pattern 19, the first common electrode pattern 14, and the second common electrode pattern 24. Therefore, the width of the transparent conductive layer formed below the second pixel electrode pattern 19, the first common electrode pattern 14, and the second common electrode pattern 24 is narrower.

Thereafter, the upper metal layer of the second pixel electrode pattern 19, the first common electrode pattern 14, and the second common electrode pattern 240 is etched to form a first common electrode 114, a second common electrode 124 and a pixel electrode 109a are formed.

For example, if the laminated metal film formed in the first masking process is Cu / MoTi / ITO, first the wet etching process for ITO is performed, and then the etching process for Cu / MoTi is performed.

Thereafter, the gate pad pattern 140a of the pad region corresponding to the halftone region and the upper metal film of the data pad pattern 130a are etched. As a result, the gate pad electrode 140 and the data pad electrode 130 are formed.

When the source / drain metal layer is formed of Cu / MoTi, the gate pad electrode 140 and the data pad electrode 130 are formed of a MoTi metal layer. However, when the source / drain metal film is formed of any one of Cu, Al, and Mo and a transparent conductive layer, the gate pad electrode 140 and the data pad electrode 130 are formed of a transparent conductive layer.

Therefore, the electrode widths of the common electrodes and the pixel electrodes formed in the pixel region of the present invention are formed to be narrower than the width of the electrodes patterned by the exposure equipment.

This is because, in the first mask process, the common electrode and the pixel electrode are primarily etched, and then the second electrode is etched in the last mask process to narrow the electrode width.

Therefore, if the width of the electrode that can be formed by the exposure equipment is 3 to 4 mu m, the width of the pixel electrode and the common electrode of the present invention is 2 mu m or less.

As described above, according to the present invention, the common electrode and the pixel electrode formed in the pixel region are reduced in occupied area, and the distance between the electrodes is widened to obtain a high aperture ratio and a high transmittance.

FIGS. 3A to 3D illustrate how the electrode widths formed according to the present invention are reduced by an etching process.

 3A to 3D, a first metal film 310 is formed on a substrate 300, a second and a third metal film are formed, and then a mask process is performed. The second and third metal patterns 320 and 330 are formed by etching the film.

Then, an etching process for etching the first metal film 310 is performed to form a first metal pattern 311. At this time, the first metal pattern 311 is formed by the difference of the etching ratio for forming the second and third metal patterns 320 and 330 and the etching ratio for forming the first metal pattern 311, An undercut is generated in the three metal patterns 320 and 330. [

For example, in the present invention, the first metal film is formed of a transparent conductive material (ITO, IZO, ITZO), and the second and third metal films are MoTi and Cu, respectively.

Then, the first, second, and third metal patterns 311, 320, and 330 are exposed in a final mask process for removing the protective film during the LCD manufacturing process. Then, a second etching process is performed on the first metal pattern 311 to form the electrode 312.

Therefore, if the width of the first metal pattern 311 that can be formed by the exposure process using the first mask is 3 to 4 占 퐉, the electrode width of the electrode 312 formed by the second etching process becomes 2 占 퐉 or less .

1 is a plan view showing a pixel structure of a liquid crystal display device according to the present invention.

2A to 2E show a manufacturing process of a liquid crystal display device according to the present invention.

FIGS. 3A to 3D illustrate how the electrode widths formed according to the present invention are reduced by an etching process.

 (Description of Reference Numbers to Main Parts of the Drawings)

100: substrate 101: gate wiring

103: Data line 109: First pixel electrode

109a: second pixel electrode 124: second common electrode

110: gate pad

Claims (6)

A transparent conductive layer and a metal film are successively formed on the substrate, and then a mask process is performed to form a gate wiring having a laminated structure of a transparent conductive layer and a metal film, a common wiring parallel to the gate wiring, A pixel electrode, a second pixel electrode pattern branched from the first pixel electrode, a first common electrode pattern of a square structure in which a pixel region is opened, a second common electrode pattern of a second common electrode pattern arranged alternately with the second pixel electrode pattern at the center of the pixel region, Forming a common electrode pattern, a gate pad extending from the gate wiring, and a data pad; Sequentially forming a gate insulating film, an amorphous silicon film, and a doped amorphous silicon film on a substrate on which the gate wiring and the like are formed, and then performing a mask process to form an active layer on the gate wiring; Forming a source / drain metal film on the substrate on which the active layer is formed, and then performing a masking process to form source / drain electrodes, parallel to the second pixel electrode pattern and parallel to the second common electrode pattern, Forming a data line, a gate pad pattern and a data pad pattern connected to the data pad; A protective film is formed on the substrate on which the source / drain electrodes are formed, and then the gate insulating film and the protective film formed on the pixel region are removed using a diffraction mask or a halftone mask, thereby forming the second pixel electrode pattern, 2 exposing the common electrode pattern; And The first common electrode, the second common electrode, and the second pixel electrode including the transparent conductive layer are formed in the pixel region by sequentially performing the etching process for the transparent conductive layer and the etching process for the metal film in the exposed pixel region ; ≪ / RTI > Wherein the pixel region is defined by intersecting the gate line and the data line. The method of manufacturing a transverse electric field type liquid crystal display device according to claim 1, wherein the metal film is formed of at least one metal film of Cu, MoTi, Al, Ag and alloys thereof. The method of claim 1, wherein forming the gate line, the common line, the first pixel electrode, the second pixel electrode pattern, the first common electrode pattern, the second common electrode pattern, Wet-angle-patterning the metal film, and wet-calibrating the transparent conductive layer using the patterned metal film as a mask. The method of manufacturing a transverse electric field type liquid crystal display device according to claim 1, wherein the mask used in the active layer formation step is a diffraction mask or a half-tone mask. The method of manufacturing a semiconductor device according to claim 4, A contact hole exposing a part of the first pixel electrode, the gate pad and the data pad is formed using the half-tone photoresist pattern patterned with the diffraction mask or the half-tone mask as a mask, and after the ashing process, Wherein the liquid crystal display device is a liquid crystal display device. The method of claim 1, wherein the widths of the first common electrode, the second common electrode, and the second pixel electrodes are 2 占 퐉 or less.

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