KR20040062015A - array substrate for liquid crystal display and fabricating method of the same - Google Patents

Abstract

PURPOSE: An LCD(liquid crystal display) and a method for manufacturing the LCD are provided to form a common electrode on a lower substrate using a black matrix. CONSTITUTION: An LCD includes an insulating substrate(200), red, green and blue color filters(202) formed on the insulating substrate, a planarization layer(206) formed on the color filters, and a gate line(212) and a data line(215) formed on the planarization layer to define a pixel region. The LCD further includes a thin film transistor connected to the gate line and data line, a pixel electrode(240) connected to the thin film transistor, and a black matrix pattern(250) formed on the thin film transistor and made of an opaque conductive material. The LCD also has a common line(270) formed of the same material as the material of the black matrix along the data line, and a common electrode(250) extended from the common line. The common electrode and the pixel electrode are alternately arranged.

Description

Liquid crystal display device and its manufacturing method {array substrate for liquid crystal display and fabricating method of the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having a color filter formed on an array substrate and a method of manufacturing the same.

Recently, with the rapid development of the information society, there is a need for a flat panel display having excellent characteristics such as thinning, light weight, and low power consumption. Among them, a liquid crystal display having excellent color reproducibility, etc. display is being actively developed.

In general, a liquid crystal display device is formed by arranging two substrates having electrodes formed on one side thereof so that the surfaces on which the two electrodes are formed face each other, injecting a liquid crystal material between the two substrates, and then applying voltage to the two electrodes. By moving the liquid crystal molecules by the electric field is a device that represents the image by the transmittance of light that varies accordingly.

The lower substrate of the liquid crystal display is formed by repeating a process of forming a thin film and photolithography with an array substrate including a thin film transistor for applying a signal to a pixel electrode. The upper substrate is a substrate including a color filter. Three colors of red (R), green (G) and blue (B) are sequentially arranged, and are produced by methods such as pigment dispersion, dyeing, and electrodeposition.

Hereinafter, a structure of a general liquid crystal display device will be described with reference to the accompanying drawings.

1 is a cross-sectional view of a general liquid crystal display.

As illustrated, a gate electrode 12 made of a conductive material such as a metal is formed on the transparent first substrate 11, and a gate insulating film made of silicon nitride (SiN _x ) or silicon oxide (SiO ₂ ) is formed thereon. 13 covers the gate electrode 12. An active layer 14 made of amorphous silicon is formed on the gate insulating layer 13 on the gate electrode 12, and ohmic contact layers 15a and 15b made of amorphous silicon doped with impurities are formed thereon.

Source and drain electrodes 16a and 16b made of a conductive material such as a metal are formed on the ohmic contact layers 15a and 15b, and the source and drain electrodes 16a and 16b are formed together with the gate electrode 12. (T).

Although not shown, the gate electrode 12 is connected to the gate wiring, the source electrode 16a is connected to the data wiring, and the gate wiring and the data wiring are orthogonal to each other to define the pixel region.

Subsequently, a passivation layer 17 made of a silicon nitride layer, a silicon oxide layer, or an organic insulating layer is formed on the source and drain electrodes 16a and 16b, and the passivation layer 17 has a contact hole 17c exposing the drain electrode 16b. .

A pixel electrode 18 made of a transparent conductive material is formed in the pixel area above the passivation layer 17, and the pixel electrode 18 is connected to the drain electrode 16b through the contact hole 17c.

Meanwhile, the second substrate 21 is disposed on the first substrate 11 and spaced apart from the first substrate 11 at a predetermined interval, and the black matrix 22 is disposed on the lower surface of the second substrate 21. ) Is formed at a position corresponding to the thin film transistor T. Although not shown, the black matrix 22 is formed on the entire surface of the substrate with an opening in a portion corresponding to the pixel electrode 18. The black matrix 22 prevents light leakage from portions other than the pixel electrode 18, and also prevents light from entering the channel of the thin film transistor T to prevent photo current from occurring. Under the black matrix 22, color filters 23a and 23b are formed to realize different colors, and the two color filters 23a and 23b sequentially repeat red, green, and blue colors. It corresponds to this one pixel area. The common electrode 24 made of a transparent conductive material is formed under the color filters 23a and 23b.

Next, the liquid crystal layer 30 is injected between the pixel electrode 18 and the common electrode 24.

The liquid crystal display is formed through a process of forming an array substrate and a color filter substrate, and arranging the lower pixel electrode and the upper color filter in a one-to-one correspondence. In the process of disposing the substrate, misalignment occurs. Defects such as light leakage can occur. In order to prevent this, the width of the black matrix of the upper substrate may be widened. In this case, the aperture ratio of the liquid crystal display becomes low.

Therefore, recently, a structure of a liquid crystal display device capable of preventing misalignment of the liquid crystal display device by forming a color filter on the array substrate and improving the aperture ratio by reducing the width of the black matrix has been proposed. The structure formed in the film is called a thin film transistor on color filter (TOC) structure.

The TOC structure liquid crystal display device will be described with reference to the drawings.

As shown in FIG. 2, in the liquid crystal display, color filters 112a and 112b are formed on the transparent first substrate 111. Three colors of red, green, and blue are sequentially formed. Is repeated.

Subsequently, a planarization layer 113 is formed on the color filter 112. The planarization layer 113 protects the color filter 112, and flattens the substrate on which the color filter 112 is formed to stabilize a subsequent process. It serves to proceed.

Next, the gate electrode 114 is formed of a conductive material such as a metal on the planarization layer 113, and the gate insulating layer 115 covers the gate electrode 114. Although not shown, the gate electrode 114 is connected to a gate line for transmitting a scan signal.

An active layer 116 made of amorphous silicon is formed on the gate insulating layer 115 on the gate electrode 114, and ohmic contact layers 117a and 117b made of amorphous silicon doped with impurities are formed thereon.

Source and drain electrodes 118a and 118b are formed on the ohmic contact layers 117a and 117b, and the source and drain electrodes 118a and 118b face each other with respect to the gate electrode 114. Together with 114, a thin film transistor T1 is formed. Here, the source electrode 118a transmits an image signal and is connected to a data line (not shown) orthogonal to the gate line, and the data line and the gate line define the pixel region.

Subsequently, a passivation layer 119 is formed on the source and drain electrodes 118a and 118b, and the passivation layer 119 has a contact hole 119c exposing the drain electrode 118b.

Next, a black matrix 120 made of an opaque conductive material is formed on the passivation layer 119 on the thin film transistor T1, and the pixel electrode 121 made of a transparent conductive material is formed on the passivation layer 119 of the pixel region. The pixel electrode 121 is connected to the drain electrode 118b through the contact hole 119c.

On the other hand, the second substrate 131 is disposed above the first substrate 111 at regular intervals and spaced apart from the first substrate 111, and the inner surface of the second substrate 131 is transparent, such as ITO. The common electrode 132 made of a conductive material is formed.

Next, a liquid crystal layer 140 is injected between the pixel electrode 121 and the common electrode 132. Although not illustrated, an alignment layer is formed at an upper portion of the pixel electrode 121 and a lower portion of the common electrode 132, respectively. The initial arrangement of the liquid crystal molecules is determined.

The present invention provides a transverse electric field liquid crystal display device having a TOC structure by forming a common electrode on a lower substrate by using the BM in forming a BM in the liquid crystal display device having a conventional TOC structure. At this time, in the manufacturing process of the TOC liquid crystal display, the common wiring is formed so as to overlap with the data wiring during the BM process, which is formed to prevent light leakage without any additional process, and the common electrode is formed to branch from the common wiring. A method of manufacturing an electric field liquid crystal display device is provided.

1 is a cross-sectional view of a general liquid crystal display device.

2 is a cross-sectional view of a general TOC structure liquid crystal display device.

3 is a plan view of an array substrate for a TOC structure liquid crystal display device according to the present invention;

4 is a cross-sectional view of an array substrate for a TOC structure liquid crystal display device according to the present invention;

5A-5D are cross-sectional views of the manufacturing process of FIG. 4.

In order to achieve the above object, an array substrate for a liquid crystal display device according to the present invention includes an insulating substrate; A red, green, and blue color filter layer on the insulating substrate; A planarization film on the color filter layer; Gate wiring and data wiring formed on the planarization film and crossing each other to define a pixel region; A thin film transistor connected to the gate line and the data line; A pixel electrode on a pixel electrode connection line partially overlapping the data line and connected to the thin film transistor; A black matrix pattern formed on the thin film transistor and made of an opaque conductive material; And a common electrode formed of a metal material forming a black matrix and overlapping the data line, and having a common line formed along the data line and branched from the common line to be alternately arranged with the pixel electrode.

In this case, the black matrix is made of any one of chromium, molybdenum and titanium.

A method of manufacturing an array substrate for a liquid crystal display device according to the present invention includes the steps of forming a color filter layer on the substrate; Forming a planarization layer on the color filter layer; Forming a thin film transistor connected to the gate line and the data line and the gate line and the data line to cross the planarization layer; Forming a passivation layer covering the gate line, the data line, and the thin film transistor; Forming a black matrix, a common wiring, and a common electrode with a conductive material on the passivation layer on the thin film transistor; Forming a pixel electrode connected to the thin film transistor on the passivation layer, the pixel electrode being alternately disposed on the common electrode and the pixel;

Hereinafter, a liquid crystal display and a manufacturing method thereof according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, FIG. 3 is a plan view of a liquid crystal display according to an exemplary embodiment of the present invention.

As illustrated, the gate wiring 210 is formed in the first direction, the data wiring 215 is formed in the second direction crossing the first direction, and the gate wiring 210 and the data wiring 215 are formed. These intersect to define the pixel region P.

A thin film transistor is formed at a point where the gate line 215 and the data line 210 cross each other, and the pixel electrode 240 is formed in connection with the thin film transistor.

In addition, the common wiring 270 is partially overlapped with the data wiring 215, and the common wiring 270 is formed in the second direction, and the common electrode 250 branches in the first direction by branching from the common wiring 217. And 240).

The thin film transistor includes a gate electrode 208 branched from the gate line 210, a source electrode 220 branched from the data line 215, and a drain electrode spaced apart from the source electrode 220 at a predetermined interval. 225.

The pixel electrode 240 partially overlaps the front gate line 210, and forms a storage capacitor of the pixel electrode 240 and the gate line 210.

The thin film transistor is also covered with a black matrix to prevent light leakage.

4 is a cross-sectional view taken along line AA ′ of FIG. 3.

As illustrated, a color filter pattern 202 is formed on the transparent substrate 200. Although not shown, the color filter 202 is formed by sequentially repeating three colors of red, green, and blue. In addition, a planarization layer 206 is formed on the color filter pattern 202 to protect the color filter pattern 202 and to planarize the surface of the color filter pattern 202 so as to stably perform the subsequent process. A metal gate electrode 212 is formed thereon, and a gate insulating film 213 is formed on the entire surface of the gate electrode 212 using an inorganic insulating material of silicon nitride or silicon oxide.

An active layer 219a made of amorphous silicon is formed on the gate insulating layer 213, and an ohmic contact layer 219 made of amorphous silicon doped with impurities is formed thereon. In addition, source and drain electrodes 220 and 225 are formed on the ohmic contact layer 219b. In the pixel region, the data line 215 is formed over the gate insulating layer 213. In addition, a passivation layer 230 is formed on the source and drain electrodes 220 and 225, and the passivation layer 230 has a contact hole 231 exposing the drain electrode 225.

Next, a black matrix 250 made of an opaque conductive material is formed on the passivation layer 230 on the thin film transistor. In addition, a pixel electrode 240 connected to the drain electrode 225 through the drain contact hole 231 is formed on the passivation layer 230.

5A through 5D are cross-sectional views illustrating a manufacturing process of FIG. 4.

First, as shown in FIG. 5A, the color filter 202 is formed on the transparent insulating substrate 200. The color filter 202 can be produced by a pigment dispersion method, a dyeing method, a printing method, etc. Among these, the pigment dispersion method is widely used because of its excellent precision and reproducibility.

Subsequently, the planarization layer 206 is formed on the color filter 202 to eliminate the step caused by the color filter 202.

Next, as shown in FIG. 5B, the gate electrode 212 is formed on the planarization layer 206 with a conductive material such as metal. In this case, a gate line (not shown) connected to the gate electrode 212 and having a first direction is also formed.

Next, a gate insulating film 213, an amorphous silicon layer, and an amorphous silicon layer doped with impurities are sequentially deposited on the gate electrode 212, and then patterned to form an active layer 219a and an impurity semiconductor layer 219b. A metal material is deposited and patterned by a sputtering method to form a source electrode 220 and a drain electrode 225 on the semiconductor layer 119. Subsequently, the ohmic contact layer 219b exposed between the source electrode 220 and the drain electrode 225 is etched to expose the active part layer 219a. In this case, the data line 215, which is connected to the source electrode 220 and extends in the second direction and crosses the gate line (not shown), defines the pixel area. Here, the source and drain electrodes 220 and 225 together with the gate electrode 212 form a thin film transistor.

Next, as shown in FIG. 5C, the passivation layer 230 is formed on the source and drain electrodes 220 and 225 with a low dielectric constant benzocyclobutene or an acryl-based organic material, and then patterned to form a drain electrode. A drain contact hole 231 exposing a portion of 225 is formed.

Next, as shown in FIG. 5D, a metal material is deposited and patterned to overlap the black matrix pattern and the data line 215 on the thin film transistor in the second direction from the common line 270 and the common line 270. A branched common electrode 250 is formed. In this case, the black matrix may be formed of any one of chromium (Cr), molybdenum (Mo), or titanium (Ti).

Next, a pixel electrode 240 is formed in the pixel region on the passivation layer 230 by depositing and patterning a material such as IZO or IZO. The pixel electrode 240 contacts the drain electrode 225 through the drain contact hole 231.

Thereafter, the array substrate may be bonded to an upper substrate having only ITO, and then liquid crystal may be injected to complete a transverse field type liquid crystal display device having a TOC structure.

In the present invention, a color filter is formed on a lower array substrate, and a black matrix is formed on a thin film transistor on an array substrate, and at the same time, a common electrode is formed to be alternated with the pixel electrode by branching from the common wiring and the common wiring as the black matrix. As a result, an array substrate for a transverse electric field type liquid crystal display device having a TOC structure can be provided without additional processing.

Claims (3)

An insulating substrate; A red, green, and blue color filter layer on the insulating substrate; A planarization film on the color filter layer; Gate wiring and data wiring formed on the planarization film and crossing each other to define a pixel region; A thin film transistor connected to the gate line and the data line; A pixel electrode on a pixel electrode connection line partially overlapping the data line and connected to the thin film transistor; A black matrix pattern formed on the thin film transistor and made of an opaque conductive material; A common electrode made of a metal material forming a black matrix and overlapping with the data line, and having a common line formed along the data line and branching from the common line to be alternately arranged with the pixel electrode. Array substrate for a liquid crystal display device comprising a. The method of claim 1, The black matrix is formed of any one of chromium, molybdenum and titanium. Forming a color filter layer on the substrate; Forming a planarization layer on the color filter layer; Forming a thin film transistor connected to the gate line and the data line and the gate line and the data line to cross the planarization layer; Forming a passivation layer covering the gate line, the data line, and the thin film transistor; Forming a black matrix, a common wiring, and a common electrode with a conductive material on the passivation layer on the thin film transistor; Forming a pixel electrode connected to the thin film transistor on the passivation layer, the pixel electrode being alternately disposed on the common electrode and the pixel; Method of manufacturing an array substrate for a liquid crystal display device comprising a.