KR20050003274A - Fabrication method of polycrystalline liquid crystal display device - Google Patents

Abstract

PURPOSE: A method for fabricating a polysilicon LCD is provided to reduce process steps by simultaneously forming a gate line including a gate electrode and a data line including a source electrode through a lift-off process. CONSTITUTION: A method for fabricating a polysilicon LCD includes the steps of preparing a substrate(301), forming an active layer on the substrate, simultaneously forming a data line and a gate line including a gate electrode on the active layer, partially exposing the data line and the active layer, forming a conductive film on the exposed data line and the exposed active layer, and forming a pixel electrode(310) on the conductive film. The data line is spaced apart from the active layer used as a channel layer. The conductive film is partially removed by a lift-off process.

Description

Method for manufacturing polysilicon liquid crystal display device {FABRICATION METHOD OF POLYCRYSTALLINE LIQUID CRYSTAL DISPLAY DEVICE}

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a method for manufacturing a polysilicon liquid crystal display device in which polysilicon is applied to an active layer.

The driving circuit separate type liquid crystal display device may be divided into a screen display unit for displaying a screen and a driving circuit unit for driving the screen display unit. The screen display unit and the driving circuit unit are separately formed and connected to each other through a TCP (Tape Carrier Package). have.

On the other hand, the liquid crystal display device integrated with the driving circuit part is more convenient in the manufacturing process than the separate liquid crystal display device with the driving circuit part by using a method of simultaneously forming the driving circuit part on the same substrate when configuring the screen display part.

In order to configure the driving circuit unit integrated liquid crystal display device, a polysilicon layer capable of forming a fine element is mainly used as a channel layer.

In addition, the liquid crystal display device using polysilicon as a channel layer is superior to the liquid crystal display device using amorphous silicon as a channel, and thus is suitable for the manufacture of a liquid crystal display device requiring high-speed operation due to excellent channel mobility. In general, the electrical mobility of amorphous thin film transistors (TFTs) is about 0.1-1 cm 2 / Vsec, whereas the electrical mobility of polycrystalline silicon TFTs fabricated using excimer lasers exceeds 100 cm 2 / Vsec. Have

Referring to FIG. 1, a driving circuit unit-integrated liquid crystal display device using the polysilicon as a channel, driving for driving the elements of the screen display unit outside the screen display unit 101 and the screen display unit in which unit pixels are arranged in a matrix form. The circuit portion 102 is formed. In the driving circuit unit 102, a driving circuit unit such as a gate driver 104 and a data driver 103 is formed.

In the driving circuit unit, an IC circuit which simultaneously configures a P-channel and an N-channel Complementary Metal Oxide Semiconductor (MOS) in one circuit to perform a function of a unit transistor forms a unit and is connected to unit pixels of a screen display unit. have.

A method of manufacturing a polysilicon liquid crystal display device will be described with reference to FIG. 2 based on a schematic cross section of a driving circuit unit including a P-channel TFT and an N-channel TFT and a screen display unit including a unit pixel.

In order to manufacture a polysilicon liquid crystal display, first, a substrate 201 is prepared and a buffer layer 202 composed of a silicon oxide film is formed on the substrate.

Amorphous silicon film 203 is deposited on the silicon oxide film by plasma enhanced chemical vapor deposition (PECVD), and heat-treated at a temperature of about 400 ° C. to be included in the amorphous silicon film. The dehydrogenation process is carried out to remove the hydrogen. Dehydrogenation of amorphous silicon is previously removed by heat treatment because hydrogen gas may explode and damage the substrate during polysiliconization of amorphous silicon.

Next, the substrate on which the amorphous silicon layer is formed is heat-treated to polycrystalline amorphous silicon. The substrate forming the liquid crystal display device is a glass substrate, and the glass substrate may be denatured by heat when a high temperature heat treatment is performed. Thus, in the process of forming a polysilicon TFT using a glass substrate, amorphous silicon may be formed by instant heat treatment at a low temperature. A laser annealing method is used that can be made of crystalline silicon.

Therefore, the substrate on which amorphous silicon is formed is irradiated with an excimer laser to change the amorphous silicon formed on the entire substrate into polycrystalline silicon (polysilicon).

After the polysilicon is formed, the active layer of the pixel electrode in the screen display unit, the P-type thin film transistor and the N-type thin film transistor in the driving circuit unit are defined by dry etching the polysilicon. 2B illustrates an active layer 203a of a pixel electrode, an active layer 203b of an N-type thin film transistor, and an active layer 203c of a P-type thin film transistor, in which an amorphous silicon layer is crystallized and etched on the silicon oxide layer 202. It is shown.

After forming an active layer made of polysilicon, a gate insulating film composed of a silicon oxide film (SiO 2) or a silicon nitride film (SiN x) for protecting the active layer and insulating the gate line to be formed thereon and the active layer is formed on the entire surface of the substrate. A gate metal is formed on the gate insulating film by the sputtering method. The gate metal is applied to a gate electrode of the screen display TFT and a gate electrode for N-TFT and P-TFT in CMOS through a photolithography process using a mask.

The gate electrode may form a gate electrode by using a double layer of aluminum and molybdenum or by applying a single layer consisting of only molybdenum for ohmic contact with an indium tin oxide (ITO) film used as a pixel electrode. .

After the gate electrode is patterned, impurity ions are implanted to form TFT elements of the pixel portion and the circuit portion into an LDD type effective to prevent leakage currents between the gate electrode, the drain and the source electrode. In order to form an N-type TFT as an implanted impurity, an element such as phosphorus (P) or arsenic (As) corresponding to a Group 5 element on the periodic table of elements that donates electrons is implanted into the polysilicon layer to form a P-type TFT. In order to do so, an element such as boron (B) corresponding to a Group 3 element on the periodic table of elements is provided.

Referring to FIG. 2D, a process of forming a lightly doped drain (LDD) TFT is formed on the entire substrate on which the gate line 205 is formed, by using a spin coating method, or the like, and then, as a photolithography process. The region where the P-type TFT is to be formed is covered and the photosensitive film of the remaining region is removed. As a result, it can be seen from FIG. 2D that the P-type TFT region is covered by the photosensitive film 206 and the remaining pixel region and the N-type TFT region are opened.

Next, the gate line 205 and the photosensitive film 206 present on the open region are applied as a mask to implant a Group 5 element such as phosphorus (P) at a low concentration. As a result, a low concentration of N-type ions is implanted into the active layer 203a of the screen display TFT and the active layer 203b of the N-type TFT of the driving circuit, and the regions of the active layer covered by the gate line are not implanted with ions. Will remain. After injecting a low concentration of phosphorus (P) ions, the photosensitive film is removed.

In the LDD type TFT, the source / drain electrode part of the active layer close to the channel layer is doped with a low concentration of impurities, and the source / drain electrode part of the region separated from the channel is doped with a high concentration of impurity ions. Similarly, in order to inject a high concentration of impurities into a region spaced apart from the gate electrode in the active layer, a photoresist is coated over the entire substrate, and the photoresist layer 207 is disposed so that the gate electrode and some active layers of the entire P-type TFT region and the N-type TFT region are covered. Pattern. The photosensitive film 207 is applied as a mask to ion implant a high concentration of N-type impurities to complete an N-type TFT.

Next, a process of forming a P-type TFT into an LDD type TFT is performed.

The process of forming the P-type TFT proceeds in the same manner as the process of making the N-type TFT as described above.

As shown in Fig. 2F, in order to configure the P-type TFT as the LDD type, the entire region where the N-type TFT is formed is covered by the photosensitive film 210, and group III ions such as boron (B) of low concentration are formed on the active layer of the P-type TFT. Inject in. As a result, the active layer 211 of the P-type TFT implanted with the low concentration of P-type ions can be confirmed through FIG. 2F.

After implanting the low concentration of P-type ions, the LD-type P is implanted by covering the N-type TFT formation region, the gate electrode of the P-type TFT, and some active layers with the photosensitive film 213 and injecting the high concentration of P-type ions as shown in FIG. 2G. Complete the type TFT.

The region implanted with the P-type or N-type ions serves as an active region connected to the source / drain electrodes of the TFT.

An insulating film 214 of a silicon nitride film or a silicon oxide film is formed over the entire substrate, and the contact hole 220 is formed in the region where the source and drain electrodes are to be formed in the TFT device. As shown in FIG. 2H, the contact hole is formed in both the TFT of the pixel portion and the driving circuit portion, and forms a source / drain electrode conductive layer on the contact hole 220 to form a source / drain electrode. .

FIG. 2I shows the formation of the source / drain electrodes on the TFT.

Next, in order to protect the TFT device formed as a result of the process, a protective film 217 mainly formed of a silicon oxide film component is formed, and the contact hole 219 is exposed on the protective film 217 so that the drain electrode of the TFT on the pixel region is exposed. To form.

The pixel electrode 218 is formed by forming an ITO film for the pixel electrode in the resultant so as to be electrically connected to the contact hole 219 and then patterning the pixel electrode 218.

In the above, a method of manufacturing a liquid crystal display device using polysilicon as a channel has been described.

A liquid crystal display device using polysilicon as a channel layer has advantages of excellent operating characteristics of the device, but has a disadvantage in that the process is very complicated.

Therefore, in manufacturing a liquid crystal display device using polysilicon as a channel, shortening of the process is the biggest problem, and various attempts have been made to solve the above problem.

An object of the present invention is to shorten the process in manufacturing a liquid crystal display device using a polysilicon as a channel layer as described above. In order to use polysilicon as a channel layer, amorphous silicon must be transformed into crystalline silicon, which is subjected to laser annealing. The laser annealing process is a time-consuming process, and in order for the polysilicon liquid crystal display device to be competitive in terms of productivity and price, it is essential to reduce the number of processes. Therefore, the present invention is devised to reduce the number of processes by simultaneously forming a gate line including a gate electrode and a data line including a source electrode and forming a gate electrode and a source electrode through a lift off process.

1 is a cross-sectional view showing a schematic structure of a conventional polysilicon liquid crystal display device in which a driving circuit portion and a screen display portion are formed on the same substrate.

2A to 2H are process steps showing a manufacturing process of a conventional polysilicon liquid crystal display device;

3A to 3G are process steps showing the manufacturing process of the polysilicon liquid crystal display device of the present invention.

********* Explanation of symbols for the main parts of the drawings ************

301: substrate 302: buffer layer

303: active layer 304: gate insulating film

305: gate electrode 306: data line

307: protective film 308: photosensitive film

309, 309a, 309b, 309c: metal thin film 310: pixel electrode

Method of manufacturing a polysilicon liquid crystal display device of the present invention comprises the steps of preparing a substrate; Forming an active layer on the substrate; Simultaneously forming a gate line including a data line and a gate electrode on the active layer; Exposing a portion of the data line and active layer; Forming a conductive film on the exposed data lines and the active layer; And forming a pixel electrode on the conductive film.

In particular, an active layer is formed, and the data line formed on the active layer is formed to be spaced apart from the active layer used as a channel layer, and the part of the exposed active layer and the conductive layer formed on the data line is removed. The process is characterized in that formed through a lift off (lift off) process.

A method of manufacturing the polysilicon liquid crystal display device of the present invention will be described in detail with reference to FIGS. 3A to 3G.

The reason why the polysilicon layer is used as the channel layer is that polysilicon has superior electric characteristics compared to amorphous silicon, and thus is suitable for liquid crystal display devices requiring high-speed operation characteristics. In addition, it is possible to simultaneously form the driving circuit unit and the screen display unit on the same substrate by minimizing the design rule has an advantage in the manufacturing process.

The basic elements of the elements constituting the driving circuit section and the screen display section are thin film transistors. In particular, TFT devices having fine design rules are used to manufacture high-quality liquid crystal display devices.

As the TFT device becomes smaller, the channel layer is also narrowed, which may cause the device to be damaged by electrons passing through the channel layer. In order to solve the above problem, in order to manufacture a high-quality liquid crystal display device, an LLD type TFT is mainly used as a thin film transistor.

Lightly doped drain (LDD) type TFTs allow the active layer adjacent to the channel layer to be doped with low concentrations of impurities to prevent the occurrence of defects in the device due to the generation of hot carriers.

The hot carriers that cause the defects of the devices described above are mainly generated from the N-type TFTs that drive the devices by electron movement into electrons, so only the N-type TFTs are made LDD-type and the majors are used as carriers. In the LDD type TFT, there is no need to configure.

Therefore, although the N-type TFT and the P-type TFT as the driving elements of the polysilicon liquid crystal display device are slightly different in the process of making the LDD type, they can be generally made through the same process.

In the description of the present invention, a manufacturing process of the polysilicon liquid crystal display device will be described centering on the manufacturing process of the P-type TFT.

First, as shown in FIG. 3, a buffer layer mainly composed of a silicon oxide film is prepared to prepare a substrate made of transparent glass and to prevent impurities, which may be included in the substrate 301, from being diffused onto an active layer to be formed thereon. 302 is formed. The buffer layer 302 may be formed by a plasma chemical vapor deposition method (PECVD).

After the buffer layer 302 is formed on the substrate 301, an active layer 303 is formed on the substrate.

In the process of forming the active layer, first, an amorphous silicon layer is formed on a substrate by a PECVD method, and the polysilicon layer is heat-treated to change into a polycrystalline silicon layer.

Amorphous silicon exists in a state in which silicon particles are arranged randomly with each other. When they are melted and recrystallized in a high-temperature furnace, they grow around the nucleus to a polysilicon layer, which is a collection of single grains with large grains. Will change.

Polysilicon has a very large grain, and the smaller the grain boundary area, the faster the movement speed of the carrier is for electrons and electric fields. This is because the carriers move through the grain boundary, because the larger the grain size, the smaller the moving distance that the carrier must move and the mobility of the carrier increases.

By the way, in the manufacturing method of the liquid crystal display element which uses a glass substrate as a board | substrate, the method of changing amorphous silicon to polysilicon by heating in high temperature urine is not suitable. This is because the glass substrate used in the manufacture of the liquid crystal display device is deformed at 600 ° C. or higher, and the substrate is deformed in a urinary furnace heated to 600 ° C. or higher.

Thus, the present invention uses a laser annealing method capable of low temperature annealing in order to transform the amorphous silicon layer formed on the substrate into a polysilicon layer.

The laser annealing method is a method of crystallizing amorphous silicon by irradiating an amorphous silicon layer formed on a substrate with a laser capable of instantaneous high temperature heating. By this method, the silicon layer can be effectively crystallized without deforming the liquid crystal display device substrate of the present invention formed of a glass material.

In particular, in the technique of forming polysilicon by laser annealing, the channel layer is formed by a sequential lateral solidification (SLS) method that completely melts the amorphous silicon layer and induces horizontal crystallization to minimize grain boundaries. It is possible to maximize the characteristics of the device by the SLS method.

The manufacturing method of the active layer used for the liquid crystal display device of the present invention is not limited to the method of heating crystallization or crystallization by laser irradiation, and any method can be used as long as it is a method capable of forming amorphous silicon with polysilicon.

Amorphous silicon formed on the substrate is formed of polysilicon, and then the polysilicon layer is patterned to define the active layer 303.

In the method of forming the active layer, a photosensitive film is coated on the polysilicon layer, the active layer pattern is patterned by photolithography, and the patterned photosensitive film is applied as a mask to dry-etch and form the active layer 303.

After the active layer is formed, a gate insulating film 304 composed of a silicon nitride film or a silicon oxide film is formed by a PECVD method.

Next, as illustrated in FIG. 3B, a conductive film for forming a gate line and a data line is deposited on the gate insulating film 304 by a sputtering method.

The conductive film constituting the gate line and the data line may be an alloy of aluminum and molybdenum or a molybdenum single layer. The conductive film used may be any metal thin film of conductivity.

The metallic conductive film is mainly formed by a sputtering method. The sputtering method is a method in which inert ions such as argon (Ar) collide with a metal target and scatter metal particles to deposit on a substrate.

Next, a process of patterning the metal thin film deposited on the gate insulating film 304 by the gate line and the data line by the sputtering method is performed.

That is, applying a photoresist film on a metal thin film by spin coating method, exposing the photoresist film by applying a mask including a pattern of a gate line and a data line on the photoresist film, removing the exposed photoresist film through a developing process and A gate line and a data line are formed by forming a photoresist pattern including a line and a data line, and etching a conductive film formed on the gate insulating layer through the photoresist pattern.

In the above process, the gate line may be formed on one side of the gate line and include a gate electrode protruding outward of the gate line, and the data line may include a source electrode protruding on one side. It is a feature of the present invention that the data line does not necessarily include a source electrode.

In the process of forming the gate line and the data line, the gate electrode 305 is formed on the active layer 303, but the data line 306 or the source electrode (not shown) is not formed on the active layer 303. It is formed spaced apart from the active layer.

That is, one feature of the present invention is that the data line 306 does not overlap with the active layer 303. The data line of the present invention should not be positioned on the active layer because the data line and the active layer are connected in the process of forming the pixel electrode without being connected to the active layer through the contact hole.

After forming a gate electrode and a data line, a process of doping impurity ions to the active layer 303 is performed by applying the gate electrode 305 as a mask.

This is a process for forming the active layer 303 into a p-type TFT. In order to form a P-type TFT, implanting group III ions such as boron (B) is implanted into the impurity ions to be implanted. Since the electroporation is used, there is no need to constitute an LDD type TFT to prevent device defects caused by hot carrier action.

Although the ion implantation process is not shown in FIG. 3B, the portion of the active layer 303 covered by the gate electrode by the implanted impurity ions has no implantation of impurity ions, and the other active layer is implanted with ions to include a carrier. do.

After the process of forming the p-type TFT is finished, the process of forming the N-type TFT formed on one side of the same plane may proceed. Although the process is not shown in the drawings, briefly described herein, the P-type TFT device region is completely covered with a photoresist film, and the N-type TFT device region is opened. A low concentration impurity is applied by applying a gate electrode formed on the N-type TFT region as a mask. In the step of implanting ions, an LDD type TFT is formed by covering a portion of the gate electrode present in the N-type TFT region and a part of the active layer present in the N-type TFT region with a photosensitive film and implanting a high concentration of impurity ions.

A plan view of the gate line and the data line formed in FIG. 3B is illustrated in FIG. 3C. Since the gate line 305a and the data line 306 are on the same layer on the gate insulating layer 304, they overlap each other.

Since the gate line and the data line should not overlap, in the region where the gate line and the data line overlap as shown in FIG. 3C, the gate line 305a or the data line 306 is shorted and the gate line 305a or the data is shorted therebetween. Pass the lines 306 so that they are not connected to each other.

3C illustrates an embodiment of shorting a portion of data line 306 and allowing a gate line to pass through between the shorts.

The remaining steps of the present invention will be described in detail with reference to the cross section that appears when A-A 'and B-B' in FIG. 3C are cut planes.

FIG. 3D shows a cross section that appears when A-A 'and B-B' in FIG. 3C are cut planes.

As shown in FIG. 3D, a gate line and a data line are formed on the gate insulating film, and then a protective film 307 of a silicon oxide film or silicon nitride film for insulating the gate line and the data line and protecting it from the outside is formed on the entire surface of the substrate. Form. As shown in FIG. 3C, the passivation layer 307 is also formed on the gate line formed between the disconnected data lines. The protective film formed between the disconnected data lines can be confirmed through a cross-sectional view taken along line BB ′ of FIG. 3D.

After the protective film 307 is formed on the entire surface of the substrate, a photosensitive film is formed on the entire surface of the substrate by spin coating, and a pattern is formed through a photolithography process. The photoresist layer is formed on the passivation layer 307 and is patterned to expose a portion of the data line 306 and a portion of the active layer 303 through etching. In addition, a portion of the disconnected data line is exposed and patterned so that the gate line 305b formed between the disconnected data lines is covered.

The protective layer 307 is etched by applying the photoresist pattern as a mask. 3E illustrates the etching of the passivation layer, and a portion of the data line 309, a portion of the active layer 303 adjacent to the data line, a portion of the active layer to be connected to the pixel electrode, and a disconnected data line end are exposed. Etch as much as possible.

As a result, as shown in FIG. 3E, the data line 306 and the gate line are exposed, the top of the active layer connected to the pixel electrode is exposed, and both ends of the disconnected data line are exposed.

A thin conductive metal thin film 309 is deposited on the resulting product. The deposited metal thin film may have a thickness of about 50 kPa to about 100 kPa.

The data line 306 and the active layer 303 are electrically connected to each other by a conductive layer deposited on the passivation layer 307 partially etched, and the metal layer may also be formed on the active layer 303 to be connected to the pixel electrode. 309 is formed to be electrically connected to the pixel electrode.

In addition, both ends of the disconnected data line are connected to each other by the metal film 309.

The thin metal film is also formed on the photosensitive film 308 formed to etch the protective film 307. The thin metal film is deposited on the entire surface of the substrate including the patterned photosensitive film 308, and then lifted off. By the method, the photosensitive film 308 and the metal thin film 309 formed thereon are removed at once.

In the lift-off method, when a metal film or the like is formed on the photosensitive film, a metal film or the like formed thereon is simultaneously removed in the process of removing the photosensitive film.

As shown in FIG. 3E, since the metal thin film 309 is partially formed on the photosensitive film 308, the metal thin film 309 may be removed by a lift-off method.

As a result, as shown in FIG. 3F, the metal thin film 309 connects the data line 306 and the active layer 303a while being connected between the data line and the active layer 303 (309a) and the pixel electrode. A portion 309b and a gate line passing between the disconnected data line and the end of the disconnected data line remain on the active layer (309c).

Indium tin oxide (ITO) film, which is a transparent electrode for forming a pixel electrode, is deposited on the resultant (Fig. 3G).

As a result of depositing the pixel electrode material on the resultant material, as shown in FIG. 3G, the pixel electrode is formed on the metal thin film 309a formed between the data line 306 and the active layer 303 and on the active layer connected to the pixel electrode. The metal thin film 309b is patterned to be formed with the metal thin film 309c formed between the disconnected data line and the gate line passing therebetween.

The pixel electrode strengthens the electrical connection between the data line 306 and the active layer 303 and is connected to the metal thin film 309b formed on the active layer 303 for electrical connection with the pixel electrode.

In addition, the disconnected data lines may be electrically connected to each other (FIG. 3G). That is, as illustrated in FIG. 3G, the pixel electrode may include metal thin films 309c formed at both ends of the disconnected data line. The data lines are connected to each other by crossing the passivation layer 307 formed on the gate line passing between the connected and disconnected data lines.

As a result, in the liquid crystal display of the present invention, the data signal input through the data line 306 is transmitted to the active layer through the metal thin film and the pixel electrode formed thereon, and passes through the channel layer to the pixel electrode connected to the metal thin film. Is connected immediately.

That is, the drain electrode with which the conventional liquid crystal display element is equipped is not necessary.

In addition, the present invention separates the data line at the point where the data line and the gate line intersect, allows the gate line to pass through the pixel electrode, and prevents a short problem that may occur because the data line and the gate line are formed on the same layer. Solve by connecting to each other in the forming step.

As described above, by forming the data line and the gate line on the same layer and electrically connecting the data line and the active layer through a lift-off process, the number of masks used is reduced, thereby simplifying the process and increasing production efficiency. It is possible to obtain an effect.

Claims (9)

Preparing a substrate; Forming an active layer on the substrate; Simultaneously forming a data line and a gate line on a substrate including the active layer; Forming a passivation layer on the data line and the gate line; Exposing a portion of the data line and active layer; Forming a metal thin film on the exposed data lines and the active layer; And forming a pixel electrode on the metal thin film. The method of claim 1, wherein one of the gate line and the data line is shorted so that the gate line and the data line are separated from each other, and the other is formed therebetween. The method of claim 1, wherein forming the active layer Forming an amorphous silicon layer on the substrate; Polycrystallizing the amorphous silicon layer; And patterning the polycrystalline silicon layer into an active layer. The method of claim 1, wherein simultaneously forming a gate line including a data line and a gate electrode on the active layer comprises: Forming a gate insulating film on the active layer; Forming a conductive film on the gate insulating film; And patterning the conductive layer into a gate line and a data line. The method of claim 1, wherein exposing the data line and a portion of the active layer comprises forming contact holes to connect the active layer and the pixel electrode to each other. The method of claim 1, wherein exposing a portion of the data line and the active layer comprises: forming a photoresist layer on the passivation layer; Patterning the photosensitive film; And removing the passivation layer by applying the patterned photoresist as a mask. The method of claim 1, wherein the forming of the metal thin film on the exposed data lines and the active layer comprises: forming the metal thin film on the entire surface of the substrate including the patterned photosensitive film; And removing the metal thin film formed on the photosensitive film and the photosensitive film simultaneously by a lift-off process. The method of claim 1, wherein forming the pixel electrode is patterned such that disconnected data lines are connected to each other. An active layer serving as the channel layer of the device; A gate line formed to be spaced apart from the active layer and passing between the disconnected data line and the disconnected data line; A contact hole formed on the active layer; A metal thin film formed on the contact hole to connect the spaced data line and the active layer; And a pixel electrode formed on the metal thin film.