KR20070036981A - Liquid crystal display device and fabrication method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method of manufacturing the same. In particular, a glass spacer having a low surface friction is patterned to maintain a cell gap of a thin film transistor and a color filter with a glass spacer, thereby restoring the restoring force of the glass spacer. The present invention relates to a liquid crystal display device and a method of manufacturing the same, which can improve the touch mura.

Glass spacer, touch mura

Description

Liquid crystal display device and fabrication method thereof

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

2 is a cross-sectional view for explaining a liquid crystal display device and a method for manufacturing the same according to the present invention.

3A to 3F include a manufacturing process of the glass spacer according to the present invention. The manufacturing process of the upper substrate of the liquid crystal display device is shown. drawing.

<Description of Signs of Major Parts of Drawings>

100: lower substrate 110: first substrate

120 gate electrode 130 gate insulating film

140: semiconductor layer 150: source electrode

160: drain electrode 170: protective film

180 contact hole 190 pixel electrode

200: common electrode 300: upper substrate

310: second substrate 312: photoresist

314: mask 316: photoresist pattern

320: glass spacer 330: black matrix

340: color filter layer 350: overcoat layer

500: liquid crystal layer 510: liquid crystal

600: thread pattern

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 and a method of manufacturing the same for improving a touch mura.

Recently, a liquid crystal display device (LCD) has been spotlighted as a next generation advanced display device having low power consumption, good portability, high technology intensiveness, and high added value.

The liquid crystal display displays an image by using optical anisotropy and polarization of the liquid crystal. The liquid crystal has an elongated structure and therefore has an orientation in the arrangement of molecules. Accordingly, the direction of the molecular array can be controlled by artificially applying an electric field to the liquid crystal.

Therefore, if the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light can be refracted in the molecular arrangement direction of the liquid crystal by optical anisotropy to display an image.

The liquid crystal display device uses a substrate that has undergone an array substrate manufacturing process for forming a switching element and a pixel electrode and a color filter substrate manufacturing process for forming a color filter and a common electrode, and includes a liquid crystal cell interposed between the two substrates. Completed through the process.

The liquid crystal cell process can be roughly divided into an alignment layer forming process for forming liquid crystal molecules, a cell gap forming process, a cell cutting process, and a liquid crystal injection process. A liquid crystal panel, which is a basic component, is manufactured.

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

As shown in FIG. 1, the upper and lower substrates 10 and 30 are spaced apart from each other by a predetermined distance, and the liquid crystal layer 20 is interposed between the upper and lower substrates 10 and 30.

A gate electrode 32 made of a conductive material such as a metal is formed on the transparent substrate 31 of the lower substrate 30, and a gate insulating layer 34 is formed on the gate electrode 32 over the entire surface of the substrate 31. Is formed.

The semiconductor layer 36 in which the active layer 36a and the ohmic contact layer 36b are sequentially stacked is formed at a position covering the gate electrode 32 on the gate insulating layer 34. Source and drain electrodes 38 and 40 are spaced apart from each other at upper portions, and a channel ch exposing a portion of the active layer 36a is exposed in the interval between the source and drain electrodes 38 and 40. channel) is formed.

In this case, the gate electrode 32, the semiconductor layer 36, the source and drain electrodes 38 and 40, and the channel ch form a thin film transistor (TFT).

Although not shown in the drawings, a gate line is formed in a first direction by being connected to the gate electrode 32, and a data line is formed in a second direction crossing the first direction and is connected with the source electrode 38. The area where the gate line and the data line cross each other is defined as the pixel area P. FIG.

In addition, a passivation layer 42 having a drain contact hole 44 is formed on the thin film transistor T, and the pixel electrode P is spaced apart at regular intervals and is disposed through the drain contact hole 44. A pixel electrode 46, which is a transparent conductive material electrically connected to 40, is formed.

The lower substrate 30 is formed on the same layer as the pixel electrode 46 on the thin film transistor T to cross the pixel electrode 40 and the common electrode 48 is formed.

In addition, a color filter layer 14 is formed below the transparent substrate 11 of the upper substrate 10 to filter only light of a specific wavelength band at a position corresponding to the pixel electrode 46. A black matrix (BM) 12 is formed at the boundary to block light leakage and light inflow into the thin film transistor T.

An overcoat layer (OC) 16 is formed under the black matrix 12 and the color filter layer 14, and a mask process is performed on the thin film transistor T region under the overcoat layer 16. The upper substrate 10 to which the patterned column spacer C / S 18 is attached is completed.

The column spacer 18 serves to maintain a constant cell gap between the upper substrate 10 and the lower substrate 30, and the organic polymer on the substrate 11 on which the overcoat layer 16 is formed. After deposition or coating of the material, it is formed by photolithography to selectively remove it. The column spacer 18 is generally formed of a resin of an organic polymer material.

Meanwhile, in order to prevent leakage of the liquid crystal layer 20 interposed between the upper and lower substrates 10 and 30 to form a cell gap between the upper and lower substrates 10 and 30, the upper and lower substrates 10 and 30 are prevented. ) Is encapsulated by the seal pattern 60.

In general, as the liquid crystal display becomes larger, column spacers are used to maintain a more stable cell gap.

In the liquid crystal display, when the liquid crystal display is touched by a force applied from the outside, when the column spacer flows, the upper and lower plates are distorted. When such a phenomenon occurs, the column spacer is caused by a restoring force. It should be restored to its original state to prevent deterioration.

However, in the case of using a column spacer formed of a conventional resin, the surface spacer of the column spacer forming material is high, and the column spacer is not restored to its original state after the touch due to the friction force with the thin film transistor substrate. There is a problem that the resulting touch Mura (Mura) occurs.

In addition, since the column spacers are formed by being stacked on top of the black matrix and the color filter layers, surface uniformity of the column spacers is not good after lamination, which makes it difficult to secure uniformity of the cell gaps when the column spacers are bonded to the lower substrate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device and a method of manufacturing the same, which can improve touch mura by patterning a glass substrate and using the glass spacer to maintain a cell gap between a thin film transistor and a color filter.

In order to achieve the above object, the present invention provides a thin film transistor formed on a first substrate, a pixel electrode formed in contact with the drain electrode of the thin film transistor and electrically spaced apart from each other, a common electrode formed to cross the pixel electrode, And a liquid crystal layer interposed between the first substrate and the second substrate on which a glass spacer is formed, and a liquid crystal layer interposed in a region in which a cell gap is maintained by the glass spacer.

In addition, in order to achieve the above object, the present invention, forming a thin film transistor on a first substrate, a pixel electrode and a common electrode on the thin film transistor, patterning a second substrate to form a glass spacer, And bonding a second substrate to face the first substrate, and interposing a liquid crystal layer in a region in which a cell gap is maintained by the glass spacer.

In addition, in order to achieve the above object, the present invention, a thin film transistor is formed on the first substrate, a common electrode is formed to be spaced apart from the gate electrode of the thin film transistor by a predetermined interval, and a pixel electrode is formed on the thin film transistor. And patterning the second substrate to form a glass spacer, bonding the second substrate to face the first substrate, and interposing a liquid crystal layer in a region where the cell gap is maintained by the glass spacer. A method of manufacturing a liquid crystal display device is provided.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

2 is a cross-sectional view for explaining a liquid crystal display device and a method of manufacturing the same according to the present invention.

As shown in FIG. 2, the liquid crystal display device is formed of a lower substrate 100 and an upper substrate 300 and a liquid crystal layer 500 interposed between the lower substrate 100 and the upper substrate 300. .

Conductive including a conductive metal such as aluminum (Al), aluminum alloy (AlNd), tungsten (W), chromium (Cr), titanium (Ti), molybdenum (Mo), etc. on the first substrate 110 formed of transparent glass. One selected from the group of metals is deposited by a sputtering method and then patterned by a mask process to form the gate electrode 120.

Next, a plasma chemical vapor deposition (PECVD) method is performed on the gate electrode 120 by depositing a gate insulating layer 130 including a silicon nitride film (SiNx), a silicon oxide film (SiO ₂ ), or a double layer thereof over the entire surface of the first substrate 110. It is formed by depositing by a method such as Plasma Enhanced Chemical Vapor Deposition (LPS) or Low Pressure Chemical Vapor Deposition (LPCVD).

The region corresponding to the gate electrode 120 is deposited on the gate insulating layer 130 by depositing pure amorphous silicon and amorphous silicon containing impurities over the entire surface of the first substrate 110 by PECVD or LPCVD and patterning by a mask process. The semiconductor layer 140 in which the active layer 140a and the ohmic contact layer 140b are stacked in this order is formed.

Aluminum (Al), aluminum alloy (AlNd), tungsten (W), chromium (Cr), titanium (Ti), molybdenum (Mo), etc., over the entire surface of the first substrate 110 on which the semiconductor layer 140 is formed. One or more metals selected from the group of conductive metals including the conductive metal are patterned by a sputtering method and then patterned by a mask process to partially overlap the ohmic contact layer 140b and the source electrode 150. The drain electrode 160 spaced apart from the predetermined distance 150 is formed.

In a spaced interval between the source electrode and the drain electrode 150 and 160, a channel (ch; channel) exposing a part of the active layer 140a is formed, and the gate electrode 120, the semiconductor layer 140, and the source are formed. The electrode 150, the drain electrode 160, and the channel Ch form a thin film transistor (TFT).

Subsequently, a protective film is formed by stacking a silicon nitride film (SiNx), a silicon oxide film (SiO ₂ ), or a double layer thereof over the entire surface of the first substrate 110 on which the source and drain electrodes 150 and 160 are formed. Further forms 170.

The passivation layer 170 protects the thin film transistor T.

Subsequently, the protective layer 170 may be formed to contact the drain electrode 160 of the thin film transistor T by wet etching or dry etching using a mask.

Indium Tin Oxide (ITO), which is a transparent conductive material, is deposited on the passivation layer 170 including the contact hole 180 by a sputtering method, and then patterned by a mask process to form a mask process. The pixel electrodes 190 are electrically connected and spaced apart from each other at regular intervals.

When the pixel electrode 190 is formed, the same transparent conductive material as the pixel electrode 190 is deposited by a sputtering method and then patterned by a mask process to be spaced apart from the pixel electrode 190 on the same layer as the pixel electrode 190. As a result, the common electrodes 200 that cross each other are formed.

As a result, the lower substrate 100 including the thin film transistor T, the pixel electrode 190, and the common electrode 200 is completed.

The pixel electrode 190 and the common electrode 200 are electrodes for applying a voltage to the liquid crystal display, and the pixel electrode 190 is applied with a voltage through the drain electrode 160, and the common electrode 200. Although not shown, a voltage is applied through the common wiring to drive the liquid crystal cell to display an image.

Subsequently, the second substrate 310 is patterned on the second substrate 310 formed of transparent glass to form an integrated glass spacer 320 connected to the second substrate 310.

Subsequently, Cr, CrOx, or a double layer thereof (Cr / CrOx) is patterned by a mask process after deposition on the entire surface of the second substrate 310 on which the glass spacer 320 is formed to form a black matrix 330. do. The black matrix 330 prevents light leakage. In this case, the black matrix 330 is not formed in the region where the glass spacer 320 is formed.

At the boundary of the black matrix 330, resins, pigments, and the like are laminated by patterning method such as pigment dispersion method, printing method, electrodeposition method, dyeing method, and then patterned by a mask process such as red, green, and blue. Color filter layers 340 are sequentially formed.

On the black matrix 330 and the color filter layer 340, acrylic (Acryl), polymer to protect the red (R), green (G), blue (B) color filter pattern and planarize the surface of the color filter layer (340) An overcoat layer 350 is further formed by depositing a resin of a polymer by a spin coating method.

As a result, the upper substrate 300 including the second substrate 310, the glass spacer 320, the black matrix 330, the color filter layer 340, and the overcoat layer 350 is completed.

Subsequently, the glass spacer 320 is positioned in the thin film transistor T region of the lower substrate 100 to be bonded to the upper substrate 300 through the seal pattern 600.

An area in which the black matrix 330 is not formed by the glass spacer 320 is formed in the gate spacer 120, the source electrode 150, or the drain electrode 160 of the thin film transistor T. ), The light leakage phenomenon can be prevented.

In addition, the glass spacer 320 may be disposed on a gate line (not shown) or a data line (not shown) of the lower substrate 100 to be bonded to the upper substrate 300 through the seal pattern 600. .

In this case, the glass spacer 320 may be flown in the glass spacer 320 of the liquid crystal display by a touch applied from the outside, so that the lower substrate 100 and the upper substrate 300 may be distorted. Since the surface frictional force of 320 is small, the glass spacer 320 may be restored to its original state by the restoring force, thereby improving the touch mura, thereby preventing deterioration of image quality due to color unevenness.

When the glass spacer 320 is positioned on the thin film transistor T, the gate wiring, or the data wiring of the lower substrate 100, the contact area with the lower substrate 100 is very small. Even if the flow of the spacer 320 occurs, it is possible to prevent the light leakage caused by this.

In addition, when the lower substrate 100 and the upper substrate 300 are bonded to each other, the surface uniformity of the glass spacer 320 positioned on the thin film transistor T, the gate wiring, or the data wiring is superior to that of the conventional resin. Stable uniformity of gap can be secured.

Although not shown, a seal pattern for bonding the lower substrate 100 and the upper substrate 300 is formed along the outside of the screen display area.

Subsequently, the liquid crystal display device is completed by injecting the liquid crystal 510 into a region where the cell gap between the lower substrate 100 and the upper substrate 300 is generated by the glass spacer 320 to form the liquid crystal layer 500. do.

Although not shown, the upper and lower alignment layers may be further included in portions of the lower substrate 100 and the upper substrate 300 that contact the liquid crystals 510, respectively, in order to easily guide the arrangement of the liquid crystals.

Although not shown in the drawings, the common electrode 200 may be formed by patterning the gate electrode 120 on the first substrate 110 of the lower substrate 100 at a predetermined interval apart from the same layer. have.

In this case, the material and the method of forming the common electrode 200 are the same as the material and the method of forming the gate electrode 120.

Subsequently, the lower substrate 100 is completed by forming the semiconductor layer 140, the source electrode 150, the drain electrode 160, and the pixel electrode 190 on the gate electrode 120.

Materials and methods for forming the semiconductor layer 140, the source electrode 150, the drain electrode 160, and the pixel electrode 190 may be the same as those of forming the pixel electrode 190 and the common electrode 200 at the same time. Since the same, it will be omitted.

3A to 3F include a manufacturing process of the glass spacer according to the present invention. The manufacturing process of the upper substrate of the liquid crystal display device is shown. Drawing.

Referring to FIG. 3A, a photoresist (PR) 312, which is a photosensitive material, is applied to the entire surface of the second substrate 310, which is transparent glass, by spin coating. The photoresist 312 may be formed of one selected from a positive type photoresist or a negative type photoresist, and the photoresist 312 according to the present invention may be ultraviolet (UV) light. A positive photoresist is used in which only this irradiated portion is removed by a developer in a development process. The mask 314 including the light blocking unit and the light transmitting unit is positioned on the second substrate 310 to which the photoresist 312 is applied, and then ultraviolet rays (UV) are irradiated onto the mask 314.

Referring to FIG. 3B, when the ultraviolet light passes through the light transmitting portion of the mask 314, after development, the photoresist 312 corresponding to the light transmitting portion of the mask 314 is removed to remove the mask 314. The photoresist pattern 316 is formed on the portion corresponding to the light blocking portion of the ().

Referring to FIG. 3C, the second substrate 310 may be formed by dry etching or wet etching using the photoresist pattern 316 of FIG. 2 formed on the second substrate 310 as a mask. ), And then the photoresist pattern 316 is removed by ashing or a photoresist strip (PR Strip) to form the glass spacer 320. Preferably, it is formed by dry etching to form a fine pattern.

Therefore, the glass spacer 320 is integrally formed with the second substrate 310 and is formed of a columnar column spacer.

Referring to FIG. 3D, Cr, CrOx, or a double layer thereof (CrOx / Cr) is deposited and patterned by a mask process by sputtering over the entire surface of the second substrate 310 on which the glass spacer 320 is formed, and then, each pixel is formed. The black matrix 330 is formed at the boundary. In this case, the black matrix 330 is not formed in the region where the glass spacer 320 is formed on the second substrate 310.

Referring to FIG. 3E, red (R) and green (G) are patterned by a mask process after lamination using a pigment dispersion method on the boundary of the black matrix 330 of the second substrate 310 on which the glass spacer 320 is formed. ) And the color filter layer 340 of blue (B) are sequentially formed.

Referring to FIG. 3F, an overcoat layer 350 may be spin-coated with one selected from acrylic and polymer based on the black matrix 330 and the color filter layer 340 to planarize the color filter layer 330. To form the upper substrate 300.

As described above, since the glass spacer 320 integrally formed with the second substrate 310, which is the transparent glass, has a low surface friction force, the glass spacer 320 is formed on the thin film transistor T, the gate wiring, or the data wiring to improve the touch mura. Since the image quality is improved and the surface uniformity is excellent, stable uniformity of the cell gap can be secured.

Although the present invention has been described in detail through specific embodiments, this is for explaining the present invention in detail, and the liquid crystal display according to the present invention and its manufacturing method are not limited thereto, and the technical features of the present invention It is apparent that modifications and improvements are possible to those skilled in the art.

As described above, the liquid crystal display according to the present invention has the effect of improving the image quality by improving the touch mura by forming a glass spacer with a glass substrate having a low surface friction force and improving the restoring force of the glass spacer.

In addition, the present invention has another effect that can ensure a stable uniformity of the cell gap through the formation of a glass spacer with excellent surface uniformity.

Claims (26)

A thin film transistor formed on the first substrate; A pixel electrode contacted with the drain electrode of the thin film transistor and electrically connected to the drain electrode; A common electrode formed to cross the pixel electrode; A second substrate spaced apart from the first substrate by a predetermined distance and having a glass spacer; And And a liquid crystal layer interposed in a region holding a cell gap by the glass spacers. The method of claim 1, And the second substrate is glass. The method of claim 1, And the glass spacer is integrated with the second substrate. The method of claim 1, The glass spacer is formed on the thin film transistor. The method of claim 1, And the glass spacers are formed on gate lines or data lines. The method of claim 1, And a black matrix and a color filter layer are further formed on the second substrate. The method of claim 6, An overcoat layer is further formed on the color filter layer. The method of claim 1, A protective layer is further formed on the thin film transistor. Forming a thin film transistor on the first substrate; Forming a pixel electrode and a common electrode on the thin film transistor; Patterning the second substrate to form a glass spacer; Bonding a second substrate to face the first substrate; And And interposing a liquid crystal layer in a region in which a cell gap is maintained by the glass spacers. The method of claim 9, And the glass spacer is integrally formed with the second substrate. The method of claim 9, The glass spacer may be formed on the second substrate through a photo process and an etching process. The method of claim 9, And the glass spacer is positioned on the thin film transistor. The method of claim 9, And the glass spacers are positioned on the gate lines or the data lines. The method of claim 9, And forming a black matrix and a color filter layer on the second substrate. The method of claim 14, And forming an overcoat layer on the color filter layer. The method of claim 9, And forming a protective layer on the thin film transistor. The method of claim 9, And the co-tone electrode is formed of the same material as that of the pixel electrode. Forming a thin film transistor on the first substrate; Forming a common electrode spaced apart from the gate electrode of the thin film transistor by a predetermined distance; Forming a pixel electrode on the thin film transistor; Patterning the second substrate to form a glass spacer; Bonding a second substrate to face the first substrate; And And interposing a liquid crystal layer in a region in which a cell gap is maintained by the glass spacers. The method of claim 18, And the glass spacer is integrally formed with the second substrate. The method of claim 18, The glass spacer may be formed on the second substrate through a photo process and an etching process. The method of claim 18, And the glass spacer is positioned on the thin film transistor. The method of claim 18, And the glass spacers are positioned on gate lines or data lines. The method of claim 18, And forming a black matrix and a color filter layer on the second substrate. The method of claim 23, And forming an overcoat layer on the color filter layer. The method of claim 18, And forming a protective layer on the thin film transistor. The method of claim 18, And wherein the common electrode is formed of the same material as the gate electrode.

Images