KR20100012720A - Substrate of display device and method for fabricating the same - Google Patents

Abstract

PURPOSE: A substrate of a display device and a method for fabricating the same are provided to prevent leaching on soda lime glass, thereby forming a zinc oxide layer. CONSTITUTION: A substrate(110) includes alkali ions. A zinc oxide layer(112) formed on the upper side of the substrate prevents leaching of the alkali ions. An insulating layer(114) is formed on the zinc oxide layer. A thin film transistor is formed on the insulating layer. A gate electrode(116) is formed on the insulating layer. A gate insulating layer(118) is formed on the gate electrode. A semiconductor layer(124) corresponding to the gate electrode is formed on the gate insulating layer. The semiconductor layer includes a channel region. A source electrode(128) and a drain electrode(130) are formed between the channel region on the semiconductor layer.

Description

Substrate of Display Device and Method for fabricating the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate of a display device and a display device using the same, and more particularly, to a display device using a leaching prevention film for preventing leaching of alkali ions on soda lime glass.

As the information society develops, the demand for display devices for displaying images is increasing in various forms, including liquid crystal display (LCD), plasma display panel (PDP), electro luminescent display (ELD), and vacuum fluorescent (VFD). Various types of display devices such as displays are used. Among the display devices, liquid crystal display devices are widely used because they have advantages of miniaturization, light weight, thinness, and low power driving. The liquid crystal display device is configured by interposing liquid crystal between two substrates facing each other. In general, a liquid crystal display device is driven by displaying an image by changing a liquid crystal array by an electric field generated between a pixel electrode and a common electrode formed on two substrates.

1 is a schematic diagram of a liquid crystal display device according to the prior art, and FIG. 2 is a cross-sectional view of the array substrate according to the prior art.

As shown in FIG. 1, the liquid crystal display device 11 according to the related art includes an upper substrate 5, a lower substrate 10, and a liquid crystal 9 interposed between the upper substrate 5 and the lower substrate 10. . The upper substrate 5 includes a plurality of color filters 7 arranged in red, green, and blue colors, a black matrix 6 formed between the plurality of color filters 7, and a plurality of color filters 7. The common electrode 18 is included on the black matrix 6. The lower substrate 10 includes a pixel region P, a pixel electrode 36 formed on the pixel region P, and a thin film transistor T. The lower substrate 10 is called an array substrate. The thin film transistor T, which is a switching element, is positioned at the intersection of the gate wiring 14 and the data wiring 22, and the pixel region P is defined by the intersection of the gate wiring 14 and the data wiring 22. As shown in FIG. On the pixel region P, a pixel electrode 36 of transparent material is formed.

2 is a cross-sectional view of an array substrate on which a thin film transistor is formed, and the thin film transistor is formed by the following process sequence.

The gate electrode 30 connected to the gate wiring (not shown) and the gate wiring by depositing and patterning aluminum (Al) or aluminum alloy (AlNd) as a first metal on the lower substrate 10 using transparent soda-lime glass. ). A gate insulating layer 32 formed of a silicon oxide film or a silicon nitride film is formed on the lower substrate 10 including the gate electrode 30 and the gate wiring. After the amorphous silicon layer is formed on the gate insulating layer 32 and the impurities are doped with the amorphous silicon layer, patterned to form an active layer 40 which is an amorphous silicon layer that is not doped with impurities, and an ohmic that is an amorphous silicon layer doped with impurities. The contact layer 42 is formed. The semiconductor layer 44 includes the active layer 40 and the ohmic contact layer 42.

On the gate insulating layer 32 including the semiconductor layer 44, aluminum (Al) or aluminum alloy (AlNd) is deposited and patterned with a second metal to pattern the data lines 22 and the semiconductor layers perpendicularly intersecting the gate lines. A source electrode 46 and a drain electrode 48 spaced apart from each other are formed on the upper portion of 44. The ohmic contact layer 42 between the source electrode 46 and the drain electrode 48 is removed and the active layer 40 is exposed to expose the gate electrode 30 between the source electrode 46 and the drain electrode 48. The channel region 50 is formed in the corresponding semiconductor layer 44.

The protective layer 52 is formed of an insulating material on the gate insulating layer 32 including the source electrode 46, the drain electrode 48, and the data line 22. The protective layer 52 corresponding to the source electrode 46 is etched to form a source contact hole 54, and a transparent conductive film is formed and patterned on the protective layer 52 including the source contact hole 54. The pixel electrode 56 is electrically connected to the electrode 46. Then, a plurality of color filters 7 in which red, green, and blue are arranged, a black matrix 6 formed between the plurality of color filters 7, and a plurality of color filters 7 and a black matrix 6 The upper substrate 5 having the common electrode 18 formed thereon is joined to the lower substrate 10 to complete the liquid crystal display device.

In the liquid crystal display device as described above, the upper and lower substrates 5 and 10 use an alkali-free glass made of a transparent and insulating material. In general, glass is classified into an alkali-free glass, soda lime glass, and borosilicate glass. Here, the soda-lime glass is a glass of Na ₂ O content of 1wt% or more, the alkali free glass of Na ₂ O content of 0.1wt% or less, and the borosilicate glass of Na ₂ O content of 0.1w% to 1w% to be. Soda-lime glass is called alkaline glass here.

Alkali glass is mainly used in an active liquid crystal display including a thin film transistor. Since soda-lime glass contains a lot of alkali ions, alkali ions are easily leached at high temperature during the manufacturing process of the liquid crystal display device. Is formed to contaminate the channel region using the semiconductor layer. By leaching alkali into the active region, the semiconductor and conductive properties of the channel region are changed so that the leakage current Ioff increases by conducting the source and drain electrodes in the channel region even when the gate voltage is turned off. Have characteristics. In addition, when contamination with alkali ions occurs to the liquid crystal, afterimage problems may occur.

Therefore, since an alkali free glass substrate does not leak alkali ions and does not cause a problem with the above, a general liquid crystal display device is manufactured using an alkali free substrate. However, alkali-free substrates are five times more expensive than soda lime glass. Although the liquid crystal display has advantages of thin film and light weight in comparison with other display elements, the cost of glass, which occupies a large portion of the price, among the components or materials in manufacturing, which has a large proportion in the manufacturing of the liquid crystal display. In order to reduce, the method of using soda-lime glass instead of an alkali free glass is searched.

In order to solve the problems of the prior art as described above, an object of the present invention is to provide a substrate of a display device provided with a leaching prevention film for preventing leaching of alkali ions on soda lime glass.

Another object of the present invention is to improve a display device having improved productivity and a manufacturing method thereof by using a substrate having a leaching prevention film on soda-lime glass.

The array substrate of the liquid crystal display device according to the present invention for achieving the above object is a substrate containing alkali ions; A zinc oxide layer formed on the substrate and preventing leaching of the alkali ions; An insulating film on the zinc oxide layer; And a thin film transistor on the insulating film.

An array substrate of a liquid crystal display device as described above, wherein the thin film transistor comprises: a gate electrode on the insulating film; A gate insulating film on the gate electrode; A semiconductor layer corresponding to the gate electrode and formed on the gate insulating layer and including a channel region; And a source electrode and a drain electrode formed on the semiconductor layer with the channel region interposed therebetween.

In the array substrate of the liquid crystal display device as described above, the zinc oxide layer is formed to a thickness of 500 to 1000 GPa.

In the array substrate of the liquid crystal display device as described above, the insulating film is formed of a silicon oxide film or a silicon nitride film, and has a thickness of 1000 GPa.

In the array substrate of the liquid crystal display device as described above, the substrate is soda-lime glass.

Method of manufacturing an array substrate in a liquid crystal display device according to the present invention for achieving the above object comprises the steps of preparing a substrate containing alkali ions; Forming a zinc oxide layer on the substrate to prevent leaching of the alkali ions; Forming an insulating film on the zinc oxide layer; And forming a thin film transistor on the insulating film.

In the method of manufacturing an array substrate in the liquid crystal display device as described above, the zinc oxide layer is formed by the reaction of a reaction material containing diethylzinc or dimethylzinc and oxygen as a source material. It is done.

In the method of manufacturing an array substrate in the liquid crystal display device as described above, the zinc oxide layer is formed at a deposition rate of 2000 mW / mim and a temperature of 200 degrees.

A liquid crystal display device for achieving the above object is formed on the lower substrate containing alkali ions, the lower substrate, the zinc oxide layer to prevent leaching of the alkali ions, the insulating film on the zinc oxide layer, and the insulating film on Thin film transistors; An array substrate including a pixel electrode connected to the thin film transistor; And a color filter substrate bonded to the array substrate and including an upper substrate including alkali ions, a color filter on the upper substrate, and a common electrode on the color filter.

In the liquid crystal display device as described above, a second zinc oxide layer and a second insulating film between the second zinc oxide layer and the common electrode are included on the color filter.

Substrate of the display device for achieving the above object, soda lime glass containing alkali ions; And a zinc oxide layer formed on the soda lime glass to prevent leaching of the alkali ions.

In the substrate of the display device as described above, the zinc oxide layer is formed to a thickness of 500 to 1000 GPa.

Substrate manufacturing method of the display device for achieving the above object comprises the steps of preparing a soda lime glass containing alkali ions; And forming a zinc oxide layer on the soda lime glass to prevent leaching of the alkali ions.

The substrate of the display device according to the present invention has the following effects.

By forming a zinc oxide layer on the soda-lime glass as a leaching prevention film, the soda-lime glass is at least five times cheaper than an alkali-free substrate without using an alkali-free substrate as a substrate of a display device, especially a liquid crystal display. It can be used to secure cost competitiveness.

Hereinafter, a first preferred embodiment of the present invention will be described in detail with reference to the drawings.

3A to 3E are cross-sectional views showing a process sequence of an array substrate of a liquid crystal display device according to the present invention, and FIG. 4 is a cross-sectional view showing a process sequence of a color filter substrate of a liquid crystal display device according to the present invention.

The manufacturing process of the lower substrate on which the thin film transistor is formed is as follows. As shown in FIG. 3A, a soda-lime glass having a Na ₂ O content of 1 wt% or more is prepared as a lower substrate 110 having a thin film transistor region T and a pixel region P, and soda-lime glass on the lower substrate 110. In order to prevent leaching, which prevents leaching of alkali metal ions, the lower leaching prevention layer 112 is formed of a zinc oxide layer. The zinc oxide layer used as the lower leaching prevention film 112 is a diethylzinc or dimethylzinc as a source material and a material containing oxygen as a reactant, for example, vapor (H 2 O) or ozone (O 3). Is injected and formed by these reactions. The method for forming the zinc oxide layer uses chemical vapor deposition (CVD), e-beam evaporation, sputtering, thermal evaporation, and the like.

 The deposition rate of the zinc oxide layer is about 2000 GPa / mim, the deposition temperature is approximately 200 degrees or less, and the thickness is 5000 to 6000 GPa. Since the zinc oxide layer is transparent and conductive, a silicon oxide film or a silicon nitride film is formed as the lower insulating film 114 on the lower leaching prevention film 112 to insulate the thin film transistor to be formed later. The lower insulating film 114 has a thickness of about 1000 mW.

As shown in FIG. 3B, the gate electrode 116 connected to the gate wiring (not shown) and the gate wiring are deposited by patterning aluminum (Al) or aluminum alloy (AlNd) on the insulating film 114 and patterning them. Form. A gate insulating film 118 formed of a silicon oxide film or a silicon nitride film is formed on the insulating film 114 including the gate electrode 116 and the gate wiring.

As shown in FIG. 3C, an amorphous silicon layer is formed on the gate insulating layer 118. Generally, the temperature at which the amorphous silicon layer is formed is at least 300 degrees. After the dopant is doped on the amorphous silicon layer, the patterned pattern is formed to form an active layer 120 which is an amorphous silicon layer that is not doped with impurities and an ohmic contact layer 122 that is an amorphous silicon layer doped with impurities. It is referred to as a semiconductor layer 124 including the active layer 120 and the ohmic contact layer 122. When the lower leaching prevention film 112 uses soda-lime glass as the lower substrate 110, in the process of forming the amorphous silicon layer, sodium ions (Na +), potassium ions (K +), And alkali ions such as magnesium ions (Mg +) to prevent leaching and diffusion into the semiconductor layer 124.

Since the zinc oxide layer 112 used as the lower leaching prevention film 112 has a high density of film quality, diffusion of alkali ions is prevented. In addition, although the silicon oxide film or the silicon nitride film can be used as the lower leaching prevention film 112, the thickness required to prevent diffusion of alkali ions is 1.0 µm or more, which is very thick compared to the zinc oxide layer, and also the silicon oxide film or Since the deposition rate of the silicon nitride film is about 1000 mV / mim, it is very slow compared to the zinc oxide layer of about 2000 mV / mim, so there is a problem of low productivity. Therefore, a zinc oxide layer having optimal conditions is used as the lower leaching prevention film 112.

As shown in FIG. 3D, on the gate insulating layer 118 including the semiconductor layer 124, aluminum (Al) or aluminum alloy (AlNd) is deposited and patterned with a second metal to pattern the data lines 126 perpendicular to the gate lines. ) And a source electrode 128 and a drain electrode 130 spaced apart from each other above the semiconductor layer 124. The ohmic contact layer 122 between the source electrode 128 and the drain electrode 130 is removed and the active layer 120 is exposed to correspond to the gate electrode 116 between the source electrode 128 and the drain electrode 130. The channel region 132 is formed in the semiconductor layer 124. By the above process, the channel region 132 corresponding to the gate electrode 116, the gate insulating film 118 on the gate electrode 116, the semiconductor layer 124 on the gate insulating film 118, and the gate electrode 116 is provided. A thin film transistor including a source electrode 128 and a drain electrode 130 formed on the semiconductor layer 124 and spaced apart from each other is formed therebetween.

If the lower leaching prevention film 112 is not formed, alkali ions of soda lime glass are diffused into the semiconductor layer 124, particularly the channel region 132. Alkali ions diffused into the channel region 132 change the semiconductor properties of the channel region 132 so that even when a voltage is not applied to the gate electrode 116, the alkali ions diffuse into the channel region 132. As a result, the source electrode 128 and the drain electrode 130 are energized to increase the leakage current.

As shown in FIG. 3E, the protective layer 134 is formed on the gate insulating layer 118 including the source electrode 128, the drain electrode 130, and the data line 126 by using a silicon oxide film or a silicon nitride film as an insulating material. do. A source contact hole 136 is formed by etching the passivation layer 134 corresponding to the source electrode 128, and a transparent conductive layer is formed and patterned on the passivation layer 134 including the source contact hole 136. The pixel electrode 138 is electrically connected to the electrode 128 and extends into the pixel region P.

The manufacturing process of the upper substrate on which the color filter is formed is as follows. As shown in FIG. 4A, a soda-lime glass having a Na ₂ O content of 1 wt% or more is prepared as the upper substrate 140, and a black matrix 142 is formed on the upper substrate 140 to prevent light leakage. . The black matrix is formed by depositing chromium (Cr) / chromium oxide (CrOx) or resin on the front surface and then patterning it.

As shown in FIG. 4B, a red color resist is formed on the upper substrate 140 including the black matrix 142 by a spin coating method, and a red color pattern 144 is formed by a proximity exposure method. The green color pattern 146 and the blue color pattern (not shown) are formed in the same manner as the red color pattern 144. The red, green and blue color resists have the characteristics of a negative photosensitive film, so that the exposed portions remain and the unexposed portions are removed.

As shown in FIG. 4C, on the upper substrate 140 including the color patterns 144 and 146 and the black matrix 142, the upper leaching prevention layer 148 prevents leaching of alkali metal ions from soda lime glass. A zinc oxide layer is formed. The formation method of the zinc oxide layer is the same as that of the zinc oxide layer used as the lower leaching prevention film 112. A silicon oxide film or a silicon nitride film is formed on the upper leaching prevention film 148 as the upper insulating film 150. A common electrode 152 for generating an electric field is formed on the upper insulating layer 150 to face the pixel electrode 138 of the array substrate. The common electrode 152 forms indium tin oxide or indium zinc oxide (IZO), which is a conductive transparent material, on the entire surface of the upper insulating layer 150.

The reason why the upper insulating film 150 is formed between the common electrode 150 and the upper leach preventing film 148 is because the zinc oxide layer used as the upper leach preventing film 148 is transparent and conductive, so that the upper leach preventing film ( This is to prevent the common electrode 152 from being affected by the conductive property of 148. The thickness of the upper insulating film 148 is about 1000 GPa. However, the temperature of the manufacturing process in the upper substrate 140 as described above proceeds below 300 degrees, so that alkali ions such as sodium ions (Na +), potassium ions (K +), and magnesium ions (Mg +) of soda lime glass If not leached, even if soda-lime glass is used as the upper substrate 140, the formation of the upper leaching prevention film 148 can be omitted. In addition, since the common electrode 150 is formed over the entire surface of the upper substrate 140, the upper insulating layer 150 may not be formed unless it is affected by the conductivity of the upper leaching prevention layer 148.

Although the bonding process of the lower substrate 110 and the upper substrate 140 is not shown through the drawings, a seal pattern is formed on either the lower substrate 110 or the upper substrate 140, and the lower substrate 110 is used as an array substrate. The thin film transistor of FIG. 2) and the color filter substrate are bonded to face the common electrode of the upper substrate 140, and the liquid crystal is filled between the lower substrate 110 and the upper substrate 140 to complete the liquid crystal display device.

In the above, the use of soda-lime glass having a leaching prevention film is representatively described. However, the present invention can be applied to all flat panel displays using a high temperature process, and the present invention is not limited to the above-described embodiments. And variations are possible.

1 is a schematic view of a liquid crystal display according to the prior art

2 is a cross-sectional view of an array substrate according to the prior art.

3A to 3E are cross-sectional views illustrating a process sequence of an array substrate of a liquid crystal display according to the present invention.

4 is a cross-sectional view illustrating a process sequence of a color filter substrate of a liquid crystal display according to the present invention.

Claims (13)

A substrate comprising alkali ions; A zinc oxide layer formed on the substrate and preventing leaching of the alkali ions; An insulating film on the zinc oxide layer; A thin film transistor on the insulating film; Array substrate of a liquid crystal display device comprising a. The method of claim 1, The thin film transistor, A gate electrode on the insulating film; A gate insulating film on the gate electrode; A semiconductor layer corresponding to the gate electrode and formed on the gate insulating layer and including a channel region; A source electrode and a drain electrode formed on the semiconductor layer with the channel region therebetween; Array substrate of a liquid crystal display device comprising a. The method of claim 1, And the zinc oxide layer is formed to a thickness of 5000 to 6000 GPa. The method of claim 1, And the insulating film is formed of a silicon oxide film or a silicon nitride film and has a thickness of 1000 mW. The method of claim 1, And the substrate is soda-lime glass. Preparing a substrate including alkali ions; Forming a zinc oxide layer on the substrate to prevent leaching of the alkali ions; Forming an insulating film on the zinc oxide layer; Forming a thin film transistor on the insulating film; Method of manufacturing an array substrate in a liquid crystal display comprising a. The method of claim 6, The zinc oxide layer is a method of manufacturing an array substrate in a liquid crystal display device, characterized in that formed by the reaction of a reaction material containing diethylzinc or dimethylzinc and oxygen as a source material. The method of claim 6, And the zinc oxide layer is formed at a deposition rate of 2000 mA / mim and a temperature of 200 degrees. A lower substrate including alkali ions, a zinc oxide layer formed on the lower substrate and preventing leaching of the alkali ions, an insulating film on the zinc oxide layer, and a thin film transistor on the insulating film; An array substrate including a pixel electrode connected to the thin film transistor; A color filter substrate bonded to the array substrate and including an upper substrate including alkali ions, a color filter on the upper substrate, and a common electrode on the color filter; Liquid crystal display comprising a. The method of claim 9, And a second zinc oxide layer on the color filter, and a second insulating film between the second zinc oxide layer and the common electrode. Soda lime glass including alkali ions; A zinc oxide layer formed on the soda lime glass and preventing leaching of the alkali ions; Substrate of the display device comprising a. The method of claim 11, And the zinc oxide layer is formed to a thickness of 5000 to 6000 GPa. Preparing a soda lime glass including alkali ions; Forming a zinc oxide layer on the soda lime glass to prevent leaching of the alkali ions; Substrate manufacturing method of a display device comprising a.

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