KR101033460B1 - Array substrate for Liquid Crystal Display Device and method for fabricating the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device, and more particularly, to an array substrate for a liquid crystal display device having a spacer.

In a liquid crystal display device, spacers are formed between the two substrates to maintain a constant gap between the array substrate and the color filter substrate. Conventionally, the spacers are distributed over the entire surface of the substrate including a display area for displaying an image, such as light leakage. Cause badness.

The present invention provides an array substrate for a liquid crystal display device, wherein the spacer is formed on only a protective layer in a region other than a display region, for example, a region corresponding to a gate wiring and a data wiring or a switching element, thereby causing light leakage due to a spacer. An array substrate and a method of manufacturing the same are provided.

Spacers, Sticky, Light Leaks, Array Boards

Description

Array substrate for liquid crystal display device and method for fabricating the same             

1 is a three-dimensional view of a portion of a general liquid crystal display device.

2 is a schematic view of a conventional liquid crystal panel, and a plan view mainly showing an active region of an array substrate.

3 is a cross-sectional view taken along the line II of FIG. 2 and illustrates only an array substrate.

4 is a plan view of an array substrate for a liquid crystal display according to an embodiment of the present invention.

5 is a cross-sectional view taken along the line II-II of FIG. 4.

6A-6G are plan views of an array substrate manufacturing process in accordance with an embodiment of the present invention.

7A-7G are cross-sectional views of the manufacturing process taken along lines II-II of FIGS. 6A-6G.

<Description of the symbols for the main parts of the drawings>

160: gate electrode 162: gate wiring

170: semiconductor layer 174: data wiring                 

180: drain contact hole 188: pixel electrode

195: spacer

P: pixel region T: switching element (thin film transistor)

The present invention relates to a liquid crystal display device, and more particularly, to an array substrate having a spacer and a method of manufacturing the same.

Recently, with the rapid development of the information society, the need for a flat panel display having excellent characteristics such as thinning, light weight, and low power consumption has emerged.

Such a flat panel display may be divided according to whether it emits light or not. A light emitting display is one that displays an image by emitting light by itself, and a display is performed by displaying an image using an external light source. It is called a display device. The light emitting display includes a plasma display panel, a field emission display, an electro luminescence display, and the light receiving display includes a liquid crystal display. display).

Dual liquid crystal display devices are being actively applied to notebooks and desktop monitors because of their excellent resolution, color display, and image quality.

The liquid crystal display device arranges two substrates on which electrodes are formed so that the surfaces on which the two electrodes are formed face each other, injects a liquid crystal between the two substrates, and then applies a voltage to the two electrodes to form a liquid crystal. It is a device that expresses an image by controlling light transmittance by moving molecules.

FIG. 1 is a three-dimensional view of a portion of a general liquid crystal display, and is shown centering on an active region defined as a region in which a liquid crystal is driven.

As shown in the figure, the upper and lower substrates 10 and 30 face each other with a predetermined distance therebetween, and the liquid crystal layer 50 is interposed between the upper and lower substrates 10 and 30.

A plurality of gates and data lines 32 and 34 cross each other on the lower substrate 30, and a thin film transistor T is formed at a point where the gates and data lines 32 and 34 cross each other. A pixel electrode 46 connected to the thin film transistor T is formed in the pixel region P defined as an area where the gate and data lines 32 and 34 intersect.

Although not shown in the drawing, the thin film transistor T adjusts the voltage on and off by a gate electrode receiving a gate voltage, a source electrode receiving a data voltage, a drain electrode, a gate voltage, and a data voltage difference. It consists of a channel (Ch; channel).

The color filter layer 12 and the common electrode 16 are sequentially formed below the upper substrate 10. Although not shown in detail in the drawing, the color filter layer 12 is composed of a color filter for transmitting only light of a specific wavelength band and a black matrix positioned at a boundary of the color filter to block light on an area where the arrangement of liquid crystals is not controlled.

In addition, upper and lower polarizers 52 and 54 for transmitting only light parallel to the polarization axis are positioned on each outer surface of the upper and lower substrates 10 and 30, and a backlight, which is a separate light source, is provided below the lower polarizer 54. light) is placed.

The liquid crystal panel for a liquid crystal display device includes a process of manufacturing an array substrate in which pixel electrodes and thin film transistors, which are switching elements, are formed for each pixel, and a common electrode and red, green, and blue colors correspond to each pixel as opposed to the array substrate. After injecting the liquid crystal between the process of manufacturing the color filter substrate is formed and the array substrate and the color filter substrate produced through the two processes, and then proceeds to a series of bonding process is completed.

Here, the manufacturing process of the liquid crystal panel for liquid crystal display devices mentioned above is demonstrated simply.

The liquid crystal panel manufacturing process is called a cell process, and the cell process combines two substrates with an alignment process for aligning liquid crystals in one direction to an array substrate on which thin film transistors are arranged and a color filter substrate on which a color filter is formed. ) Can be roughly divided into a cell gap forming process, a cell cutting process, and a liquid crystal injection process.

Each process will be described in more detail in the cell process.                         

The first step of the cell process is an alignment layer forming process, in which a thin film transistor is arranged on each pixel and a polyimide, which is a polymer material, on a color filter substrate in which red, green, and blue color filters are formed corresponding to the pixels of the array substrate. ) To form an alignment layer. The alignment film, which is the polyimide, is printed on the front surface of the array substrate and the color filter substrate so as to have a predetermined pattern mainly by a roll coating method. Thereafter, the two substrates on which the alignment layer is printed are preliminarily dried and baked to form a cured alignment layer.

Next, the upper and lower substrates on which the cured alignment layer is formed undergo a rubbing process, which is the second step of the cell process. The cured alignment layer surface is rubbed with a rubbing cloth at a uniform pressure and speed to align the polymer chains on the alignment layer surface in a predetermined direction. The rubbing is a main process of determining the initial alignment direction of the liquid crystal, and has a normal display drive and normal driving of the liquid crystal.

Next, the rubbed two substrates undergo a third step of seal pattern printing, Ag dotting, and spacer dispersing.

The color filter substrate, which is mainly an upper substrate, performs a seal printing process, and the array substrate, which is a lower substrate, undergoes silver dotting and spacer dispersing processes. In the liquid crystal panel, the seal pattern serves to form a gap for liquid crystal injection and to prevent leakage of the injected liquid crystal. The seal pattern is a process of forming a sealant, which is a thermosetting or ultraviolet curable resin, in a desired pattern on the edge of the substrate in a predetermined pattern. The seal pattern is made of a screen mask method and a dispenser method. .

Application of silver (Ag) is to apply a certain amount of silver paste to a predetermined position of the lower substrate for the conduction of the upper substrate and the lower substrate.

Next, the silver (Ag) coated lower substrate is subjected to a spacer scattering process of spraying a spacer for maintaining a cell gap between the upper and lower substrates with a uniform density on the front surface of the substrate. There are a dry method and a wet method for the spacer spread, and a dry method in which the spacer is dispersed without aggregation of the spacer by charging with + and-is mainly used.

After the spacer spreading process of the lower substrate is finished, the fourth process is a bonding process.

In order to bond the upper substrate and the lower substrate, the color filter pattern of the upper substrate and the pixels of the lower substrate must be exactly matched. In this case, the degree of adhesion alignment is determined by a margin given during the design of each substrate, and the adhesion margin is due to the degree of overlap between the black matrix on the color filter substrate and the pixel electrode on the array substrate. A few micrometers of precision is required. If the two substrates are out of the bonding error range, light leaks out, so that the desired image quality characteristics cannot be obtained when the liquid crystal cell is driven. After bonding, the upper and lower substrates are bonded to form a disc panel, and then the seal pattern is firmly cured while maintaining a constant cell gap by applying uniform pressure and temperature to the disc panel.

Next, a cell cutting process of cutting the disc panel, which is the fifth step, is performed. It is the process of cutting the original panel manufactured by the previous step into the unit cell. The cell cutting process is a scribe process that forms a cutting line on the surface of the disc panel with a cutting wheel made of diamond or cemented carbide, which is harder than a glass substrate, and a break process that breaks apart by applying force to the cutting line. Is done.

Next, a sixth step of the liquid crystal injection process is performed on the liquid crystal panel cut into unit cells by performing the cutting process. The liquid crystal injection process injects a liquid crystal into the liquid crystal panel by using a capillary phenomenon and an atmospheric pressure difference after evacuating the inside of the liquid crystal panel having a cell gap of several μm. After the liquid crystal injection is completed, the injection hole into which the liquid crystal is injected is sealed with an encapsulant, and the encapsulant is cured by irradiating ultraviolet rays.

Next, a grinding process for removing the pad portion shorting bar of the liquid crystal panel and an inspection process for determining whether the defect is defective are performed to complete the liquid crystal panel.

FIG. 2 is a schematic view of a conventional liquid crystal panel completed by the aforementioned cell process, and is a plan view mainly showing an active region of an array substrate, and FIG. 3 is a cross-sectional view of the liquid crystal panel of FIG. 2 taken along II. to be.

As illustrated, a plurality of horizontal gate lines 62 and a plurality of vertical data lines 74 intersect to form a plurality of pixel regions P. The pixel regions P may have a plurality of pixel regions P. The thin film transistor T which is a switching element is formed at the intersection of the wirings 62 and 74. In addition, the pixel electrode 88 is formed in the pixel region P by being connected to the thin film transistor T.

Referring to FIG. 3, which is a cross-section of a thin film transistor and a display region, the thin film transistor forming part TA includes a gate electrode 60, a gate insulating film 68 on the top, and an active layer on the gate insulating film 68. The semiconductor layer 70 including the 70a and the ohmic contact layer 70b is formed, and the source and drain electrodes 76 and 78 are formed in contact with the ohmic contact layer 70b and spaced apart at regular intervals. In addition, a protective layer 86 is formed on the entire surface of the substrate 59 on the two electrodes 76 and 78, and the pixel electrode 88 is in contact with the drain electrode 78 above the protective layer 86. Is formed. Although not shown, a color filter substrate (not shown) is formed to face the array substrate 58, and a liquid crystal layer (not shown) is formed between the two substrates 58 (not shown). In addition, a spacer 95 is formed between the two substrates 58 (not shown) to maintain a constant gap between the two substrates 58 (not shown).

On the other hand, it can be seen that the spacer 95 is distributed on the entire surface of the substrate 59 including the display area area PA for displaying an image. The spacer is generally formed in a spherical shape having a direct line of several μm, and is formed to bond the array substrate and the color filter substrate together to form a gap, ie, a cell gap, between the two substrates when the liquid crystal panel is formed.

However, in the conventional liquid crystal panel, which proceeds by advancing the array substrate in which the thin film transistors are arranged as described above and the color filter substrate having red, green, and blue color filters by the above-described cell process, the spacer is an image of the liquid crystal panel. Since it is also distributed on the display area to be displayed, there is a problem that light leakage occurs by the spacer when driving the liquid crystal panel.

Accordingly, the present invention has been made to solve the above-mentioned problem, and the spacer scattering process, which has been performed in the cell process, is performed in the array substrate manufacturing process so as to be distributed only in the region other than the display region where the image is displayed. The purpose is to prevent light leakage.

According to an aspect of the present invention to achieve the above object, a substrate; A plurality of gate lines and data lines intersecting with each other provided on the substrate; A pixel region defined by crossing the two wirings; A switching element formed at intersections of two wirings in the pixel region; A protective layer provided on the front surface of the substrate including the switching element; A pixel electrode provided over the passivation layer and connected to the switching element in the pixel area; The present invention provides an array substrate for a liquid crystal display device including a spacer disposed on an upper portion of a passivation layer except a portion where the pixel electrode is formed.

Except for the portion where the pixel electrode is formed, the region is a switching element that does not overlap the pixel electrode, and the gate and data wiring region. The spacers have a spherical shape with a diameter of 1 μm to 10 μm, particularly, when the spacer receives proper heat. It is preferable that it is a fixed spacer which melt | dissolves the surface and adheres firmly to a board | substrate.

On the other hand, in another aspect of the present invention, forming a plurality of gate wiring and data wiring crossing each other on the substrate and the switching element at the intersection of the two wiring; Forming a protective layer over the switching element, the protective layer exposing a portion of the switching element; Forming a transparent metal layer on a front surface of the protective layer; Forming a photoresist layer on the entire surface of the transparent metal layer; Exposing and developing the photoresist layer to expose a transparent metal layer corresponding to a portion of the two wires and the switching element; Removing the exposed transparent metal layer to expose a lower protective layer; Dispersing a spacer over the exposed protective layer and the undeveloped photoresist layer; Fixing the scattered spacers to the protective layer and the photoresist layer; Provided is a method of manufacturing an array substrate for a liquid crystal display device comprising stripping and removing a photoresist layer having the spacer fixed thereon.

In this case, forming a plurality of gate wirings and data wirings crossing each other on the substrate and a switching element at an intersection point of the two wirings may include forming a gate wiring and a gate electrode branched from the gate wiring on the substrate. Wow; Forming a gate insulating film over the gate wiring and the gate electrode; Forming a semiconductor layer on the gate insulating layer to correspond to the gate electrode; The method may further include forming a source and drain electrode spaced apart from a region corresponding to the gate electrode on the semiconductor layer, and a data line connected to the source electrode and crossing the gate line. Dispersion can be by dry or wet methods.

Meanwhile, the spacer has a spherical shape having a diameter of 1 μm to 10 μm, and the fixing of the spacer is performed by applying heat to the substrate on which the spacer is dispersed for a suitable time.

Hereinafter, preferred embodiments according to the present invention will be described with reference to the accompanying drawings.

4 is a plan view of an array substrate for a liquid crystal display device according to an exemplary embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along line II-II of FIG. 4.

As shown, the gate wiring 162 extends in the horizontal direction, and the data wiring 174 is formed to cross the gate wiring 162 in the vertical direction. In addition, the pixel region P is defined by crossing the two wirings 162 and 174, and the thin film transistor T serving as the switching element is formed at the intersection of the two wirings 162 and 174. In the pixel region P, the pixel electrode 188 is connected to the thin film transistor T.

In this case, the cross-sectional structure of the array substrate will be briefly described with reference to FIG. 5.

5 is a cross-sectional view of a portion of a display area in which a thin film transistor and a pixel electrode, which are switching elements, are formed.

As illustrated, a gate electrode 160 branched from the gate wiring 162 is formed on the transparent substrate 159, and a gate insulating layer 168 is formed on the entire surface of the substrate 159 over the gate electrode 160. have. A semiconductor layer 170 is formed on the gate insulating layer 168 to form an amorphous silicon and an amorphous silicon doped with impurities to form an active layer 170a and an ohmic contact layer 170b, respectively. And source and drain electrodes 176 and 178 are formed in contact with 170b).                     

Next, a passivation layer is formed on the source and drain electrodes 176 and 178, and the pixel electrode 188 is formed on the passivation layer in contact with the drain electrode 178.

In the above-described array substrate for a liquid crystal display device, it can be seen that a spacer 195 is formed on the substrate 159. In this case, the spacer 195 is not distributed on the pixel electrode 188 in the pixel region P, but is distributed only on the gate wiring 162 and the data wiring 174 or the thin film transistor T. . Accordingly, since no spacer 195 is present on the pixel electrode 188 corresponding to the display unit, light leakage may occur around the spacer 195.

The spacer 195 is a fixed-type spacer. When the spacer is spread and heated at an appropriate temperature, the adhesive material on the surface of the spacer melts and adheres firmly to the surface of the array substrate.

Next, a method of manufacturing an array substrate for a liquid crystal display device having a spacer according to the present invention will be described with reference to FIGS. 6A to 6E and 7A to 7G.

First, as shown in FIGS. 6A and 7A, one selected from a metal material such as aluminum (Al), aluminum alloy (AlNd), chromium (Cr), and molybdenum (Mo) may be formed on the transparent substrate 159. A metal layer is formed on the entire surface to form a metal layer, and a series of mask processes including a photoresist coating, exposure, development, and etching process are performed to form a gate electrode 160 including the gate wiring 162 made of one of the above-described metal materials. .

Next, as illustrated in FIGS. 6B and 7B, silicon oxide (SiO ₂ ) or silicon nitride (SiNx), which is an inorganic insulating material, is deposited on the substrate 159 on which the gate electrode 160 and the gate wiring 162 are formed. Thus, the gate insulating film 168 is formed on the entire surface.

Next, an amorphous silicon and an impurity doped amorphous silicon are sequentially deposited on the gate insulating layer 168 to form an amorphous silicon layer 169a and an impurity doped amorphous silicon layer 169b (hereinafter referred to as n + layer), and a mask The process leaves the amorphous silicon layer 169a and the n + layer 169b only in the thin film transistor forming unit TA, and the amorphous silicon layer 169a and the n + layer 169b in the remaining regions including the display area PA. ) To remove it.

Next, as shown in FIGS. 6C and 7C, a metal material, for example, aluminum (Al), is formed on the substrate 159 on which the amorphous silicon layer (169a of FIG. 7B) and the n + layer (169b of FIG. 7B) are formed. Alternatively, one of aluminum alloy (AlNd), chromium (Cr), and molybdenum (Mo) may be deposited on the entire surface, and patterned by performing a mask process to form source and drain electrodes 176 and 178 and data lines 174. Thereafter, the n &lt; + &gt; layer (169b of FIG. 7B) exposed at intervals between the source and drain electrodes 176 and 178 is etched to expose the lower amorphous silicon layer 170a so as to expose the source and drain electrodes 176 and 178. The n + layer 170b in contact with the N + layer 170b forms the ohmic contact layer 170b, and the amorphous silicon layer 170a forms the semiconductor layer 170 forming the active layer 170a.

Next, as shown in FIGS. 6D and 7D, one of silicon oxide (SiO ₂ ) or silicon nitride (SiNx), which is an inorganic insulating material, is formed on the entire surface of the substrate 159 on which the source and drain electrodes 176 and 178 are formed. A protective layer 186 having a drain contact hole 180 that exposes a portion of the drain electrode 178 by deposition and patterning is formed.

Next, as shown in FIGS. 6E and 7E, a transparent metal layer is deposited on the protective layer 186 by depositing one of indium tin oxide (ITO) or indium zinc oxide (IZO), which is a transparent conductive material, on the entire surface. Form 187. Thereafter, a photoresist layer 191 is formed by applying a photoresist on the entire surface of the transparent metal layer 187, and an exposure process, which is one of mask processes, is performed, and the exposed photoresist layer 191 is continuously developed. By removing the photoresist layer (not shown) formed on the thin film transistor forming unit TA except for the portion of the photoresist layer 191 corresponding to the display area PA in which the image is displayed, the transparent metal layer (187 in FIG. 7E) is removed. ). Next, the exposed transparent metal layer 187 of FIG. 7E is removed by performing an etching process to expose the lower protective layer 186.

Next, as shown in FIGS. 6F and 7F, a spacer 195 is evenly distributed over the exposed protective layer 186 and the remaining photoresist layer 191 to form the spacer 195 evenly on the entire surface. do. In this case, there are a dry method and a wet method in the dispersion of the spacer 195, and a dry method of dispersing the spacer 195 without agglomeration by charging with + and − is mainly used.

The spacer 195 scattered and evenly formed on the substrate 159 has a sphere shape having a diameter of about 1 μm to about 10 μm, and is made of a material such as acrylic, divinylbenzene, benzoguamine resin, or silica. In order to prevent defects such as nipples, a fastening type is mainly used, in which a surface thereof is melted and fixed to a substrate so that the surface is melted and not moved.

In the embodiment of the present invention, it is preferable to form the fixed spacer 195.

Subsequently, the substrate 191 formed on the entire surface of the spacer 195 is maintained at a predetermined temperature to fix the spacer 195 to the exposed protective layer 186 and the photoresist layer 191 so as not to move.

Next, as shown in FIGS. 6G and 7G, the substrate 159 including the fixed spacers 195 is subjected to a stripping process so that the photoresist layer remaining in the display area PA where an image is displayed (FIG. 191 of 7 is removed to expose the underlying transparent metal layer 188. In this case, the exposed transparent metal layer forms a pixel electrode 188. During the strip process, the spacers 195 formed and fixed on the photoresist layer 191 of FIG. 7 are stripped and removed together with the photoresist layer 191, so that the spacers are disposed in the display area PA where an image is displayed. The spacer 195 is not present and the spacer 195 is formed only on the gate line 162, the data line 174, or the thin film transistor forming unit TA in the pixel area P, and thus the spacer in the display area PA. Defects such as light leakage by 195 can be prevented.

As described above, the array substrate for a liquid crystal display device according to the present invention proceeds with the distribution of the spacer at the time of manufacturing the array substrate, and furthermore, the spacer is formed in the display portion displaying an image of the pixel area on the substrate to prevent defects such as light leakage Unlike conventional array substrates, the spacers are formed only on the thin film transistor forming unit or the gate or the data line except for the display unit, thereby making it possible to manufacture a high-quality liquid crystal display device without deterioration of image quality such as light leakage. It has an effect.

Claims (9)

delete delete delete delete Forming a plurality of gate wirings and data wirings crossing each other on a substrate, and a switching element at an intersection of the two wirings; Forming a protective layer over the switching element, the protective layer exposing the drain electrode of the switching element; Forming a transparent metal layer on a front surface of the protective layer; Forming a photoresist layer on the entire surface of the transparent metal layer; Exposing and developing the photoresist layer to expose a transparent metal layer corresponding to a portion of the two wires and the switching element; Removing the exposed transparent metal layer to expose a lower protective layer to form a pixel electrode in contact with the drain electrode in a pixel region defined as an area surrounded by the gate wiring and the data wiring; Dispersing a spacer having a spherical shape over the unprotected photoresist layer corresponding to the exposed protective layer and the pixel electrode; Fixing the scattered spacers to the protective layer and the photoresist layer; Stripping and removing the photoresist layer on which the spacer is fixed to expose the pixel electrode located under the spacer; Method of manufacturing an array substrate for a liquid crystal display device comprising a. The method of claim 5, Forming a plurality of gate lines and data lines crossing each other on the substrate, and a switching element at an intersection point of the two lines; Forming a gate wiring and a gate electrode branched from the gate wiring on a substrate; Forming a gate insulating film over the gate wiring and the gate electrode; Forming a semiconductor layer on the gate insulating layer to correspond to the gate electrode; Forming a source electrode and the drain electrode spaced apart from a region corresponding to the gate electrode on the semiconductor layer, and a data line connected to the source electrode and crossing the gate line; Method of manufacturing an array substrate for a liquid crystal display device further comprising. The method of claim 5, A method of manufacturing an array substrate for a liquid crystal display device, wherein the spacer is spread by a dry method or a wet method. The method of claim 6, The spacer is a spherical shape, the diameter of 1㎛ 10㎛ manufacturing method of an array substrate for a liquid crystal display device. The method of claim 5, The fixing of the spacer is a method of manufacturing an array substrate for a liquid crystal display device by applying heat to the substrate on which the spacer is dispersed.

Images