KR101048983B1 - Liquid crystal display device having a partially crystallized thin film transistor and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device having a partially crystallized thin film transistor, and a method of manufacturing the same, comprising: an array substrate having a gate line and a data line arranged in a matrix and having a thin film transistor formed at an intersection thereof; A color filter substrate bonded to the array substrate; A liquid crystal layer filled between the array substrate and the color filter substrate; And a driver driver integrated circuit part formed on the array substrate and connected to a pad part formed at one end of the data wiring and the gate wiring, wherein the number of parts is increased and the cost is increased by embedding a driver driving circuit on the substrate. It can be suppressed.

Excimer laser, crystallization, ohmic contact layer, driving driver circuit

Description

Liquid crystal display device having a partially crystallized thin film transistor and manufacturing method therefor {LIQUID CRYSTAL DISPLAY HAVING THIN FILM TRANSISTOR CRYSTALLIZED PARTLY AND METHOD THEREOF}

1 is a plan view illustrating a liquid crystal display device connected to a conventional driver driver circuit.

2A through 2F are cross-sectional views illustrating a method of manufacturing a staggered thin film transistor according to the prior art.

3 is a plan view showing a configuration of a liquid crystal display device having a driver driver in a substrate in the liquid crystal display device having a partially crystallized thin film transistor according to the present invention;

4A to 4G are cross-sectional views of a manufacturing process of a liquid crystal display device having a partially crystallized thin film transistor according to the present invention.

-Code description of main parts of drawing-

111: transparent substrate 113: gate electrode

115: gate insulating film 117: semiconductor layer

119: ohmic contact layer 121: diffractive photosensitive film pattern

123: PR ashing process 125: source electrode

127: drain electrode 129: protective layer                 

131 contact hole 133 pixel electrode

135: gate wiring 137: gate pad

145: data wiring 147: data pad

100 crystallization process 200 gate driver circuit portion
300: data driver circuit

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 using a partially crystallized thin film transistor and a manufacturing method thereof.

In general, a liquid crystal display (LCD) is arranged by placing two substrates on which the field generating electrodes are formed so that the surfaces on which the two electrodes are formed face each other, and injecting a liquid crystal material between the two substrates. In this case, the liquid crystal molecules are moved by an electric field generated by applying a voltage to the two electrodes, thereby displaying an image by the transmittance of light which varies accordingly.

The liquid crystal display includes a liquid crystal display panel in which liquid crystal cells in pixel units are arranged in a matrix, and a driving circuit for driving the liquid crystal cells.

The liquid crystal display panel may be formed at a color filter substrate and a thin film transistor array substrate, which are opposed to each other at a predetermined interval, and are spaced apart from the color filter substrate and the thin film transistor array substrate. It consists of a liquid crystal layer.

In addition, a plurality of data lines for transmitting image information to the liquid crystal cells on the thin film transistor array substrate of the liquid crystal display panel; A plurality of gate lines for transmitting the scan signal to the liquid crystal cells are orthogonal to each other, and liquid crystal cells are defined at each intersection of the data lines and the gate lines.

A common electrode and a pixel electrode are formed on opposite inner surfaces of the color filter substrate and the thin film transistor array substrate to apply an electric field to the liquid crystal layer. Here, the pixel electrode is formed for each liquid crystal cell on the thin film transistor array substrate, while the common electrode is integrally formed on the entire surface of the color filter substrate.

Therefore, by controlling the voltage applied to the pixel electrode in a state where a voltage is applied to the common electrode, it is possible to individually control the light transmittance of the liquid crystal cells.

As described above, in order to control the voltage applied to the pixel electrode for each liquid crystal cell, a thin film transistor used as a switching element is formed in each liquid crystal cell.

The driving circuit may include a gate driver supplying a scan signal to the gate lines, a data driver supplying image information to the data lines, a timing controller controlling driving timing of the gate driver and the data driver; It includes a power supply for supplying a variety of driving voltages used in the liquid crystal display.

The timing controller controls driving timing of the gate driver and the data driver through image information and control signals supplied from an external graphic processor, and supplies image information to the data driver.

The power supply unit drives the common voltage Vcom, the gate high voltage Vgh, the gate low voltage Vgl, and the gamma reference voltage Vref used in the liquid crystal display using power supplied from an external graphic processor. The voltage is generated and supplied to the gate driver, the data driver, the gamma voltage generator, and the liquid crystal display panels.

The gate driver sequentially supplies scan signals to the gate lines so that the liquid crystal cells arranged in a matrix form are selected one by one, and the selected one line of liquid crystal cells is passed through the data lines from the data driver. Image information is supplied.

The image information is separately supplied to the pixel electrodes of the liquid crystal cells, and the common voltage Vcom is supplied to the common electrode, so that an electric field is applied to the liquid crystal layer according to the voltage difference between the pixel electrode and the common electrode. The light transmittance can be individually adjusted to display a desired image.

The data driver and the gate driver directly connected to the liquid crystal display panel are integrated into a plurality of integrated circuits (ICs).

The data driving ICs and the gate driving ICs are respectively mounted on a tape carrier package (TCP) and connected to a liquid crystal display panel in a tap automated bonding (TAB) manner, or chip on glass. glass: Hereafter, it is mounted on a liquid crystal display panel by COG) method.                         

The data driver ICs and gate driver ICs mounted on the TCP and connected to the liquid crystal display panel in a tab manner are input from the outside through signal lines mounted on a printed circuit board (PCB) connected to the TCP. Control signals and direct current voltages are supplied, and are also connected to each other.

That is, the data driving ICs are connected in series through signal lines mounted on the data PCB, and are commonly supplied with image information, control signals, and driving voltages applied from the above-described timing controller and power supply.

The gate driving ICs are connected in series through signal lines mounted on the gate PCB, and are commonly supplied with control signals and driving voltages applied from the above-described timing controller and power supply.

In this regard, a conventional liquid crystal display device connected to an external driver driver circuit will be described with reference to FIG. 1.

1 is a circuit diagram illustrating a conventional liquid crystal display device connected to an external driver driver circuit.

Referring to FIG. 1, a conventional liquid crystal display device includes an array substrate 11 having a gate line 15 and a data line 45 arranged in a matrix form, and a thin film transistor formed at an intersection thereof, the array substrate 11, and the array substrate 11. It includes a color filter substrate (not shown) to be bonded and a liquid crystal layer (not shown) filled between the two substrates.

Here, data wirings 45 and gate wirings 15 are arranged on the array substrate 11 vertically and horizontally, and data pads 47 and gate pads 37 are formed at one end of each wiring.

In addition, an external gate driver integrated circuit 40 is attached to the gate pad 37, and an external data driver integrated circuit 50 is attached to the data pad 47 to apply a gate signal and a data signal. do.

The thin film transistor unit 10 serving as a switching element is formed at the intersection of the gate line 15 and the data line 45 to apply a voltage to the liquid crystal layer (not shown).

On the other hand, in the conventional liquid crystal display device having the above configuration, the lower substrate includes a thin film transistor which is a switching element. In the semiconductor layer used for the thin film transistor, amorphous silicon (a-Si: H) is the mainstream. It is coming true. This is because amorphous silicon can be formed on a large substrate such as a low cost glass substrate at low temperature.

In addition, the thin film transistor structure of the liquid crystal display device has an inverted staggered type. Since the inverted staggered thin film transistor is formed by continuously depositing an insulating film, amorphous silicon, and impurity amorphous silicon in one chamber, Since the interface between the insulating film and the amorphous silicon is not exposed to air, it has the advantage of improving the interface characteristics of the thin film transistor.

Meanwhile, a method of manufacturing an array substrate of an existing liquid crystal display device having such a configuration will be described with reference to FIGS. 2A to 2F.

2A through 2F are cross-sectional views illustrating a method of manufacturing a staggered thin film transistor according to the prior art.

As shown in FIG. 2A, first, a transparent substrate 11 is prepared, and after the cleaning process is performed to remove foreign substances on the transparent substrate 11, a metal material is sputtered on the cleaned transparent substrate 11. After the deposition, the metal material layer is exposed and developed by a first mask process and selectively etched to form a gate wiring 15 including the gate electrode 13 and the gate pad 37. In this case, since the metal material forms a lower metal layer, the metal material is formed of a metal layer including aluminum having low specific resistance.

Then, as shown in FIG. 2B, a gate insulating film 17 is formed of an insulating material such as a silicon oxide film on the substrate on which the gate wiring 15 is formed, and then a semiconductor layer on the gate insulating film 17 is subsequently formed. For use, an ohmic contact layer 21 made of an amorphous silicon layer 19 and an impurity amorphous silicon that lowers the contact resistance between the amorphous silicon layer and the metal layer and semiconductor layer to be formed later is deposited.

Subsequently, as shown in FIG. 2C, the ohmic contact layer 21 and the gate insulating layer 19 are selectively removed by a second mask process to form the semiconductor layer pattern 21a and the ohmic layer pattern 19a. . In this step, the semiconductor layer pattern 19a, that is, the active layer is formed in the thin film transistor unit 10, and the semiconductor layer 19 is etched in the gate pad unit 20 to expose the gate insulating layer 17.

Next, as shown in FIG. 2D, a metal material is deposited on the entire substrate including the semiconductor layer pattern 19a, and then the metal material layer is selectively etched by a third mask process to drain the source electrode 23 and the drain. The electrode 25 and data wirings (not shown) are formed. At this time, a portion of the ohmic contact layer pattern 19a between the source electrode 23 and the drain electrode 25 is etched to form a channel 27 of the thin film transistor unit.

Subsequently, as shown in FIG. 2E, the protective layer 29 covering the data electrode 23 and the gate electrode 25 is deposited on the upper surface of the entire structure, and then the protective layer 29 is formed by a fourth mask process. Is selectively removed to form a contact hole 31 exposing the drain electrode 25. In this case, the contact hole 33 of the gate pad part 37 is also formed when the contact hole 31 is formed.

Next, as illustrated in FIG. 2F, a transparent conductive material is deposited on the protective layer 29 including the contact hole 31, and then selectively removed to remove the transparent conductive material by a fifth mask process. A pixel electrode 35 electrically connected to the 25 is formed. At this time, in the gate pad part, a gate pad electrode 37 having a double layer contacting the gate pad 15 through the gate pad contact hole 33 is formed in the step. In addition, indium tin oxide (ITO) is mainly used as the transparent conductive material.

As described above, according to the thin film transistor of the conventional liquid crystal display device, amorphous silicon, which can be formed on a large substrate such as a low-cost glass substrate at a low temperature, is used as a semiconductor layer, but amorphous silicon is used in the field effect transfer polycrystalline silicon. In comparison, the driver of a thin film transistor requiring high mobility could not be embedded on a glass substrate.

Accordingly, the gate driver and the data driver, as shown in FIG. 1, must be separately purchased and attached to the outside, and a printed circuit board for controlling the gate driver must be used. Therefore, the number of parts increases and the cost increases. do.

Accordingly, the present invention has been made to solve the above problems according to the prior art, and has a partially crystallized thin film transistor capable of embedding a driver driving circuit on the substrate to suppress an increase in the number of parts and a cost increase. It is an object of the present invention to provide a liquid crystal display and a method of manufacturing the same.

In addition, another object of the present invention is to add a laser crystallization equipment can utilize the existing amorphous silicon line as it is, to simplify the manufacturing process compared to the conventional polysilicon process, partially crystallized thin film that can reduce the cost A liquid crystal display device having a transistor and a method of manufacturing the same are provided.

According to an aspect of the present invention, there is provided a liquid crystal display device having a partially crystallized thin film transistor, comprising: an array substrate having a gate line and a data line arranged in a matrix and having a thin film transistor formed at an intersection thereof; A color filter substrate bonded to the array substrate; A liquid crystal layer filled between the array substrate and the color filter substrate; And a driver driver integrated circuit unit formed on the array substrate and connected to a pad unit formed at one end of the data line and the gate line.

In addition, a method of manufacturing a liquid crystal display device having a partially crystallized thin film transistor for achieving the above object comprises the steps of providing an array substrate defined by a driver driver circuit portion and a pixel portion; Forming a gate electrode and a gate wiring on the array substrate; Sequentially forming a semiconductor layer including a gate insulating layer and amorphous silicon and an ohmic contact layer including impurity amorphous silicon on the entire substrate including the gate electrode and the gate wiring; Selectively etching the ohmic contact layer and the semiconductor layer to form a semiconductor layer pattern and an ohmic contact layer pattern on the gate insulating layer on the gate wiring; Removing a portion of the ohmic contact layer pattern to define a channel portion in the semiconductor layer pattern; Crystallizing the semiconductor layer pattern and the ohmic contact layer pattern positioned in the driver driver circuit except the pixel region; Forming a conductive material on the ohmic contact layer and selectively removing the conductive material to form a source and a drain electrode; Forming a protective film exposing the drain electrode on the entire substrate; And forming a pixel electrode connected to the drain electrode on the passivation layer.

Hereinafter, a liquid crystal display having a partially crystallized thin film transistor and a method of manufacturing the same according to the present invention will be described with reference to the accompanying drawings.

3 is a plan view showing the configuration of a liquid crystal display device having a driving driver in a substrate in a liquid crystal display device having a partially crystallized thin film transistor according to the present invention.

Referring to FIG. 3, in the partially crystallized liquid crystal display according to the present invention, an array substrate 111 in which a gate line 135 and a data line 145 are arranged in a matrix form and a thin film transistor is formed at an intersection thereof, the array substrate And a color filter substrate (not shown) bonded to the 111 and a liquid crystal layer (not shown) filled between the two substrates.                     

In addition, the data wiring 145 and the gate wiring 135 are arranged on the array substrate 111 vertically and horizontally, and data pads 147 and gate pads 137 are formed at one end of each wiring. Here, the plurality of gate pads 137 is connected to the gate driver integrated circuit unit 200, and the data pad 147 is connected to the data driver integrated circuit unit 300 to receive a gate signal and a data signal. Here, the gate driver integrated circuit unit 200 and the data driver integrated circuit unit 300 are arranged on the array substrate 111.

At the intersection of the gate line 135 and the data line 145, a thin film transistor serving as a switching element is formed to apply a voltage to the liquid crystal layer (not shown).

A method of manufacturing a liquid crystal display device having a partially crystallized thin film transistor according to the present invention having the above configuration will be described with reference to FIGS. 4A to 4G.

4A to 4G are cross-sectional views of a manufacturing process of a liquid crystal display device having a partially crystallized thin film transistor according to the present invention.

As shown in FIG. 4A, a transparent substrate 111 is prepared, a cleaning process is performed to remove foreign substances on the transparent substrate 111, and a metal material is sputtered on the cleaned transparent substrate 111. After the deposition, the metal material layer is exposed and developed with a first mask and selectively etched to form a gate wiring 135 including a gate electrode 113 and a gate pad 137. In this case, since the metal material forms a lower metal layer, the metal material includes a metal layer including aluminum having low specific resistance.

Next, a gate insulating film 115 is formed of an insulating material such as a silicon oxide film on the substrate on which the gate electrode 135 is formed, and then an amorphous silicon layer (100) is used on the gate insulating film 115 for use as a semiconductor layer. 117 and an ohmic contact layer 119 made of impurity amorphous silicon that lowers the contact resistance between the amorphous silicon layer 117 and the metal layer and semiconductor layer to be formed later.

Subsequently, as shown in FIG. 4B, after the photosensitive material is coated on the ohmic contact layer 119, diffraction exposure is performed on the ohmic contact layer covering the gate wiring by diffractive exposure of the photosensitive material layer using a second mask. The photosensitive film pattern 121 is formed. At this time, the thickness of the upper portion of the gate electrode 113 of the photoresist pattern 121 remains thinner than the thickness of the pattern portion located on both sides of the gate electrode.

Subsequently, the ohmic contact layer 119 and the amorphous silicon layer 117 exposed to the outside are sequentially etched using the diffracted photoresist pattern 121 as a mask.

Subsequently, as shown in FIG. 4C, the PR ashing process 123 may be performed to selectively etch the ohmic contact layer 119 positioned in the channel portion of the semiconductor layer to selectively etch the channel portion 117b of the semiconductor layer. ). At this time, when the ohmic contact layer 119 is etched, the photoresist pattern 121 is also removed by a predetermined thickness.

Next, as shown in FIG. 4D, the remaining photoresist pattern 121 is etched and then the semiconductor layer pattern 117 is selectively crystallized by the partial crystallization process 100 using an excimer laser. At this time, during the crystallization step 100 of the semiconductor layer, only the driver driver integrated circuit unit A is crystallized, and the pixel unit B is not crystallized. In addition, when the semiconductor layer is crystallized, impurity electrons in the ohmic contact layer 119 diffuse into the semiconductor layer 117a to form a source and a drain, and a pure polysilicon layer is formed in the channel region 117b. do.

Subsequently, as illustrated in FIG. 4E, the metal material is deposited on the entire substrate including the semiconductor layer, and then the source material 125 and the drain electrode 127 are selectively etched by a third mask process. And the data wiring 145 is formed. In this case, the metal forming the source electrode 125 and the drain electrode 127 is made of a metal having strong chemical corrosion resistance and excellent heat resistance, such as tungsten, molybdenum, titanium, and indium.

Subsequently, as shown in FIG. 4F, the protective layer 129 covering the data electrode 125 and the gate electrode 113 is deposited on the top surface of the entire structure, and then the protective layer 129 is formed by a fourth mask process. Is selectively removed to form a contact hole 131 exposing the drain electrode 127.

Next, as illustrated in FIG. 4G, the transparent conductive material is deposited on the protective layer 129 including the contact hole 131, and then selectively removed to remove the transparent conductive material by a fifth mask process. A pixel electrode 133 electrically connected to the 125 is formed. In this case, indium tin oxide (ITO) is mainly used as the transparent conductive material.

On the other hand, although not shown in the drawing, the black matrix, the color filter, and the common electrode are placed on the color filter substrate which is disposed at a position facing the array substrate with a predetermined distance from the thin film transistor having the above configuration. Subsequently, an alignment layer is formed on the color filter and the array substrate.

Thereafter, a liquid crystal layer is filled in a predetermined space between the array substrate and the color filter substrate to form a liquid crystal display panel having a thin film transistor which is partially crystallized.

As described above, the partially crystallized thin film transistor formed using the fifth mask process has a mobility that is several times larger than that of a transistor using amorphous silicon, so that a gate driver can be embedded in a substrate.

Therefore, according to the present invention, in the case of the conventional liquid crystal display device, since the gate driver is separately attached from the outside, the cost required is reduced and the image quality of the liquid crystal display device is improved.

In addition, according to the present invention, there is a lot of advantages in manufacturing a liquid crystal display device because not only the ion doping is used in a fair manner but also the laser crystallization equipment is introduced, and the existing production line using amorphous silicon can be used as it is.

As described above, according to the liquid crystal display device using the partially crystallized thin film transistor according to the present invention, since the mobility of the partially crystallized thin film transistor formed using the fifth mask process is several times larger than that of the transistor using amorphous silicon, the substrate Since the drive driver circuit portion can be built in, an increase in the number of parts and a cost increase can be suppressed.                     

In addition, according to the present invention, by adding only the laser crystallization equipment can use the existing amorphous silicon line as it is, simplify the manufacturing process compared to the existing polysilicon process, and reduce the cost of manufacturing the liquid crystal display device Can be.

On the other hand, while described above with reference to a preferred embodiment of the present invention, those skilled in the art various modifications of the present invention without departing from the spirit and scope of the invention described in the claims below And can be changed.

Claims (11)

An array substrate defined by a driving circuit portion region and a pixel portion region; Gate wirings and data wirings arranged in a matrix in a pixel area of the array substrate; A thin film transistor formed at an intersection point of the gate line and the data line; A crystallized thin film transistor formed in a region of the driving circuit of the array substrate; A driver driver circuit part formed in an area of a driver circuit part of the array substrate and connected to a pad part formed at one end of the data line and the gate line; A color filter substrate bonded to the array substrate; And And a liquid crystal layer filled between the array substrate and the color filter substrate. delete The liquid crystal display device of claim 1, wherein the driver driver circuit part comprises a gate driver driver circuit part and a data driver driver circuit part. Providing an array substrate defined by a driving driver circuit portion and a pixel portion; Forming a gate electrode and a gate wiring on the driver driver circuit portion and the pixel portion of the array substrate; Sequentially forming an ohmic contact layer made of impurity amorphous silicon together with a semiconductor layer made of amorphous silicon and a gate insulating film on the entire substrate including the gate electrode and the gate wiring; Selectively etching the ohmic contact layer and the semiconductor layer to form a semiconductor layer pattern and an ohmic contact layer pattern on the gate insulating layer on the gate wiring; Selectively removing the ohmic contact layer pattern to define a channel part in the semiconductor layer pattern; Crystallizing a semiconductor layer pattern and an ohmic contact layer pattern positioned in the driver driver circuit unit; Forming a source and a drain electrode by forming a conductive material on the entire surface of the substrate including the crystallized ohmic contact layer of the driving driver circuit part and the ohmic contact layer pattern of the pixel part and selectively removing the conductive material; Forming a protective film on the entire substrate and selectively removing the protective film to form a contact hole exposing a drain electrode formed in the driver driver circuit part and the pixel part; And And forming a pixel electrode connected to the drain electrode through the contact hole on the passivation layer. 5. The method according to claim 4, wherein the ohmic contact layer and the semiconductor layer are patterned by using a diffraction exposure mask. The method of claim 4, wherein the removing of the ohmic contact layer pattern corresponding to the channel part is performed by a photoresist (PR) ashing process. . The method of claim 4, wherein crystallizing the semiconductor layer pattern and the ohmic contact layer pattern positioned in the driver driver circuit is performed by a laser crystallization process. The method of claim 4, further comprising: forming a black matrix, a color filter, and a common electrode on the color substrate bonded to the array substrate, and filling a liquid crystal layer between the array substrate and the color filter substrate. A liquid crystal display device having a partially crystallized thin film transistor, characterized in that the configuration. 5. The partially crystallized thin film transistor according to claim 4, wherein impurity electrons in the ohmic layer pattern diffuse into the semiconductor layer pattern during the crystallization of the semiconductor layer pattern and the ohmic contact layer pattern positioned in the driver driver circuit. Liquid crystal display device manufacturing method comprising a. The method of claim 9, wherein the semiconductor layer pattern portion in which the impurity electrons are diffused in the ohmic layer pattern is used as a source electrode and a drain electrode. 10. The method of claim 9, wherein, in the crystallization step, the channel portion of the semiconductor layer pattern is pure polysilicon.

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