KR100707025B1 - TFT-LCD and method for fabricating the same - Google Patents

Abstract

The present invention discloses a thin film transistor liquid crystal display device and a method of manufacturing the same. According to an aspect of the present invention, there is provided a method of manufacturing a thin film transistor liquid crystal display device, the method including: forming a driving circuit unit on an edge surface of a single crystal silicon substrate; Forming a transparent oxide film on the entire surface of the single crystal silicon substrate including the driving circuit unit; Forming a thin film transistor array on a portion corresponding to the display area on the transparent oxide film; Forming a color filter layer on the thin film transistor array; Bonding an upper glass substrate to the color filter layer under an intervening liquid crystal layer; Forming an organic pattern on a rear surface of the single crystal silicon substrate to cover the driving circuit unit; Etching away the portion of the single crystal silicon substrate corresponding to the display area not covered by the organic pattern so that the transparent oxide film is exposed; And attaching a lower glass substrate to be in contact with a side surface of the remaining single crystal silicon substrate on the rear surface of the transparent oxide film from which the single crystal silicon substrate is removed and exposed. According to the present invention, since the driving circuit portion and the thin film transistor are formed on the single crystal silicon substrate, the single crystal silicon substrate portion of the thin film transistor forming portion is etched, and then the glass substrate is attached to form a thin film transistor liquid crystal display device. The process limitations can be overcome, and thus, a thin film transistor liquid crystal display device capable of high resolution with high resolution and fast response speed can be realized.

Description

Thin film transistor liquid crystal display device and manufacturing method therefor {TFT-LCD and method for fabricating the same}

1 to 4 are cross-sectional views illustrating a method of manufacturing a thin film transistor liquid crystal display device according to an exemplary embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

1: Single Crystal Silicon Substrate 2: Driving Circuit

3: transparent oxide film 4: thin film transistor array

5: color filter 6: protective film

7: upper glass substrate 8: organic pattern

9: lower glass substrate

The present invention relates to a thin film transistor liquid crystal display device, and more particularly, to a thin film transistor liquid crystal display device having a high resolution and a fast response speed and capable of realizing a high image and a method of manufacturing the same.

Liquid crystal displays have been developed in place of CRT (Cathode Ray Tube) on the basis of the advantages of low weight, low voltage driving and low power consumption. In particular, the Thin Film Transistor Liquid Crystal Display (TFT-LCD) has realized high quality, large size, and color matching comparable to CRT. It is used.

Such a TFT-LCD typically includes a liquid crystal panel in which a lower substrate on which a TFT array is formed and an upper substrate on which a color filter is formed are bonded to each other under a liquid crystal layer, and a driving circuit for applying a driving signal to the liquid crystal panel.

On the other hand, in the above-mentioned TFT-LCD, the thin film transistor which is a switching element has used amorphous silicon as its channel layer. By the way, the amorphous silicon has a low mobility and high light leakage characteristics, showing a limitation in manufacturing a high-quality LCD of the large screen.

In addition, since the thin film transistor adopts amorphous silicon as the channel layer, the drive driver IC of the driving circuit part adopts a single crystal silicon layer as the channel layer, so that the liquid crystal panel and the driving circuit part are manufactured by a separate process when manufacturing the TFT-LCD. After that, they must be connected, and the whole process is complicated, and in terms of integration degree, it is not preferable.

Therefore, in order to solve the above problems, a technique for applying polysilicon as a channel layer of a thin film transistor has been recently researched and developed. For example, polysilicon thin films are currently formed by recrystallization by excimer laser irradiation, CGS (Continuous Grain Silicon), MILC (Metal Induced Lateral Crystalization) and SLS (Sequential Lateral Solidification) after deposition of the amorphous silicon thin film.

In this case, since the polysilicon thin film is used as the channel layer of both the thin film transistor and the driving drive IC, it is possible to easily implement a high-quality LCD with a large screen and to simplify the process because the thin film transistor and the driving circuit part can be simultaneously formed on a single glass substrate. And a reduction in manufacturing cost.

However, the above-mentioned polysilicon thin film transistors have an advantage in that high-resolution panels can be manufactured because they have higher charge mobility than amorphous silicon thin film transistors, but the integration cost required for the panels is increased and the manufacturing cost must be lowered. Limitations in satisfying charge mobility are shown.

Therefore, a method of fabricating a TFT-LCD by fabricating a panel having a driving circuit portion on a single crystal silicon substrate and then bonding the single crystal silicon substrate to a glass substrate has been proposed. However, this method has a problem in that the single crystal silicon substrate is broken in a process of thinly cutting the single crystal silicon substrate on which the driving circuit unit is formed and bonding the glass substrate to the glass substrate.

In addition, as an alternative to this method, a method of forming a thin film transistor and a driving circuit part by polishing a top surface of the single crystal silicon substrate after bonding the single crystal silicon substrate to a glass plate and then forming a thin film transistor is proposed in Korean Laid-Open Patent No. 2002-0016678. It has been.

However, in this method, since the mirrored silicon upper surface must be polished and made thin, there is a problem in that the portion of the driving circuit must be kept as a mirror during the thinning process, and also the portion corresponding to the display area is Since the part into which the driving circuit enters cannot be distinguished, there is a problem in that the transmittance of the panel is lowered, and in addition, there is a problem in that the substrate heating is limited because the process must be performed with the glass substrate to which the single crystal silicon substrate is attached.

Accordingly, the present invention has been made to solve the above problems, to apply a single crystal silicon to the channel layer of the thin film transistor and the driving circuit, but to provide a TFT-LCD and a manufacturing method that can overcome the process limitations The purpose is.

In addition, another object of the present invention is to provide a TFT-LCD and a method of manufacturing the same, which enable high resolution and high resolution.

In order to achieve the above object, the present invention, a single crystal silicon substrate formed with a driving circuit portion on the surface; A lower glass substrate attached to a side of the single crystal silicon substrate; A transparent oxide film disposed on the single crystal silicon substrate and the lower glass substrate; A thin film transistor array formed on a portion of the transparent oxide layer on the lower glass substrate; A color filter layer formed on the thin film transistor array; And an upper glass substrate bonded to the color filter layer under an intervening liquid crystal layer.

In addition, in order to achieve the above object, the present invention comprises the steps of forming a driving circuit portion on the edge surface of the single crystal silicon substrate; Forming a transparent oxide film on the entire surface of the single crystal silicon substrate including the driving circuit unit; Forming a thin film transistor array on a portion corresponding to the display area on the transparent oxide film; Forming a color filter layer on the thin film transistor array; Bonding an upper glass substrate to the color filter layer under an intervening liquid crystal layer; Forming an organic pattern on a rear surface of the single crystal silicon substrate to cover the driving circuit unit; Etching away the portion of the single crystal silicon substrate corresponding to the display area not covered by the organic pattern so that the transparent oxide film is exposed; And attaching a lower glass substrate to a rear surface of the transparent oxide film from which the single crystal silicon substrate is removed and exposed to contact the side surface of the remaining single crystal silicon substrate.

Here, the transparent oxide film is formed to a thickness of 5000 ~ 10000Å, the thin film transistor is applied to the amorphous silicon or polycrystalline silicon as its channel layer.

(Example)

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

The present invention forms a thin film transistor and a driving circuit part on a single crystal silicon substrate, and then attaches the upper glass substrate thereon. Then, the entire rear surface of the single crystal silicon substrate is made thin, and then the lower glass substrate is attached to the rear surface of the thin single crystal silicon substrate thus formed to form a single crystal silicon TFT-LCD.

In this way, the conventional problem that the single crystal silicon substrate is broken can be solved because it is not necessary to cut the single crystal silicon substrate thinly. In addition, since the rear surface of the mirrored single crystal silicon substrate is removed instead of the upper surface, the problem of maintaining the mirror state of the portion where the driving circuit should be entered, and the portion corresponding to the display area and the portion where the driving circuit enters It is possible to solve the problem of lowering the transmittance of the panel and the problem of limiting the heating of the board due to indistinguishability.

1 to 4 are cross-sectional views illustrating a method of manufacturing a TFT-LCD according to an embodiment of the present invention.

Referring to FIG. 1, after the cleaned single crystal silicon substrate 1 is provided, the necessary driving circuit portion 2 is formed on the edge surface of the substrate 1 according to a known process. Then, the transparent oxide film 3 is formed on the entire surface of the substrate 1 including the driving circuit unit 2. In this case, the transparent oxide film portion formed on the driving circuit part 2 serves to protect the driving circuit part 2, and the transparent oxide film part formed on the display area where the thin film transistor array is to be formed serves to support the thin film transistor. do.
Here, the thickness of the transparent oxide film 3 should be at least 5000 kW or more, and there is no problem in the subsequent process. On the contrary, if the thickness of the transparent oxide film 3 is greater than 10000 kW, the thickness of the transparent oxide film 3 may be thick, which may cause a problem in connection between the driving circuit and the thin film transistor. The thickness is appropriately adjusted to about 5000 to 10000 Pa.

Next, the thin film transistor array 4 is formed on the display area of the single crystal silicon substrate 1 on which the transparent oxide film 3 is formed. At this time, since the single crystal silicon substrate 1 has a higher thermal stability than a glass substrate or a quartz substrate, the single crystal silicon substrate 1 has flexibility in applying a thermal process when forming a thin film transistor.

On the other hand, in forming the thin film transistor, amorphous silicon is used as the channel layer, or polycrystalline silicon which has been recrystallized by laser annealing, CGS, MILC or SLS after deposition of the amorphous silicon thin film is adopted.

Next, the thin film transistor array 4 forms the red, green and blue color filter layer 5, the black matrix (not shown), the spacer and the overcoating layer (not shown) on the substrate resultant.

Here, in the case of a conventional transmissive single crystal TFT-LCD, since a high resolution is required, if a color filter layer is formed on a separate substrate and then bonded together, there may be a problem in alignment. Therefore, in the present invention, a black matrix, a spacer, and an overcoating layer including the color filter layer 5 are formed on the single crystal silicon substrate 1 to solve the alignment problem. In addition, the present invention prevents the single crystal silicon substrate 1 from breaking when the lower surface of the single crystal silicon substrate 1 is subsequently made thin by forming the above components. In addition, the formation of the color filter layer 5 on the thin film transistor uses a known color filter on array (COA) technique.

Meanwhile, reference numeral 6, which is not described, indicates a protective film formed to protect the driving circuit unit 2, and the protective film 6 serves as an adhesive agent between the substrates when the upper glass substrate is subsequently bonded under the intervening liquid crystal layer. It also serves as a sealant to prevent the liquid crystal layer from leaking out. In addition, although not described in detail, the protective film 6 may be formed by a screen printing method commonly used in a liquid crystal display device manufacturing process, and may be formed in a desired shape through a typical photolithography process. It is possible.

Subsequently, the upper glass substrate 7 is bonded onto the substrate resultant up to this step. In this case, the upper glass substrate 7 may be deposited on a surface in which a transparent conductive layer such as ITO is in contact with the color filter layer 5 according to a driving method.

Although not shown and described, a liquid crystal layer is interposed between the single crystal silicon substrate 1 and the upper glass substrate 7 formed up to the color filter layer 5, and the liquid crystal layer is formed in a one drop filling method. Accordingly, the film is placed on the single crystal silicon substrate 1 first and then deposited, or after bonding with the upper glass substrate 7, the liquid crystal is injected.

Referring to FIG. 2, the organic pattern 8 is formed on the rear surface of the single crystal silicon substrate 1 so as to cover the entire surface of the driving circuit unit 2.

Referring to FIG. 3, the portion of the single crystal silicon substrate not covered by the organic pattern 8 is etched back, thereby exposing the rear surface of the transparent oxide film portion formed in the display area.

Here, the typical technique for making a single crystal silicon substrate thin is CMP (Chemical Mechanical Polishing) process. According to the CMP process, the lower surface of the single crystal silicon substrate can be polished and thinned easily, and when the excessive polishing is performed, the single crystal silicon substrate can be completely removed. However, it is not preferable to completely remove the single crystal silicon substrate in this way, since the driving circuit portion is also removed together. Therefore, in the embodiment of the present invention, an etching process is used instead of CMP to remove only the single crystal silicon substrate portion on the display area while preventing the loss of the driving circuit portion.

Referring to FIG. 4, an organic pattern used as an etching mask is removed during the etching of the single crystal silicon substrate 1. Then, the lower glass substrate 9 is bonded to contact the single crystal silicon substrate remaining on the rear surface of the transparent oxide film 3 on the exposed display area by removing the single crystal silicon substrate 1 and thereby, the present invention. Complete the TFT-LCD according to. At this time, the bonding between the transparent oxide film 3 and the lower glass substrate 9 uses a method such as using an adhesive.

In the TFT-LCD manufacturing method of the present invention as described above, since the driving circuit portion and the thin film transistor are formed without thinning the single crystal silicon substrate, the single crystal silicon substrate is thinned after bonding the single crystal silicon substrate to the glass substrate. Then, the problem of breaking the single crystal silicon substrate in comparison with the method of forming the driving circuit portion, or the method of forming the driving circuit portion and the thin film transistor on the single crystal silicon substrate and then thinning the single crystal silicon substrate to attach the glass substrate, substrate Process limitations such as a problem of limitation in heating and a problem of lowering transmittance of a panel can be overcome.

In addition, since the TFT-LCD of the present invention forms a thin film transistor on a single crystal silicon substrate, it is possible to implement a high mobility switching device, that is, a thin film transistor, so that high resolution and high response speed can be realized. can do.

As described above, according to the present invention, after forming the driving circuit portion and the thin film transistor on the single crystal silicon substrate, the single crystal silicon substrate portion of the thin film transistor forming portion is etched, and then a glass substrate is attached to form a TFT-LCD. Therefore, it is possible to manufacture a TFT-LCD having a high mobility device and high panel transmittance.

In addition, the present invention can manufacture a high-mobility TFT-LCD, it is possible to implement a high-resolution TFT-LCD having a high resolution and fast response speed.

Meanwhile, although specific embodiments of the present invention have been described and illustrated, modifications and variations can be made by those skilled in the art. Accordingly, the following claims are to be understood as including all modifications and variations as long as they fall within the true spirit and scope of the present invention.

Claims (4)

A single crystal silicon substrate having a driving circuit portion formed on a surface thereof; A lower glass substrate attached to a side of the single crystal silicon substrate; A transparent oxide film disposed on the single crystal silicon substrate and the lower glass substrate; A thin film transistor array formed on a portion of the transparent oxide layer on the lower glass substrate; A color filter layer formed on the thin film transistor array; And An upper glass substrate bonded to the color filter layer by interposing a liquid crystal layer; A thin film transistor liquid crystal display comprising a. Forming a driving circuit portion on an edge surface of the single crystal silicon substrate; Forming a transparent oxide film on the entire surface of the single crystal silicon substrate including the driving circuit unit; Forming a thin film transistor array on a portion corresponding to the display area on the transparent oxide film; Forming a color filter layer on the thin film transistor array; Bonding an upper glass substrate to the color filter layer under an intervening liquid crystal layer; Forming an organic pattern on a rear surface of the single crystal silicon substrate to cover the driving circuit unit; Etching away the portion of the single crystal silicon substrate corresponding to the display area not covered by the organic pattern so that the transparent oxide film is exposed; And Attaching a lower glass substrate to a rear surface of the transparent oxide film from which the single crystal silicon substrate is removed and exposed to the side surface of the remaining single crystal silicon substrate; The thin film transistor liquid crystal display device manufacturing method comprising a. The method of claim 2, wherein the transparent oxide film is formed to a thickness of 5000 to 10000 GPa. The method of claim 2, wherein the thin film transistor is formed of amorphous silicon or polycrystalline silicon as its channel layer.

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