KR20020069414A - A thin film transistor array panel for liquid crystal display and a method for manufacturing the same - Google Patents

Abstract

PURPOSE: A TFT(Thin Film Transistor) substrate for an LCD device is provided to electrically connect one data line with pixel electrodes of both two pixels neighboring with the data line, to transmit an image signal, and to connect each of the pixels with different gate lines, thereby reducing the number of data driving ICs. CONSTITUTION: A gate wire comprises as follows. Dual gate lines(22) are extended toward the top and the bottom of pixels in horizontal direction, and transmit scanning signals. Gate electrodes(26) of the first and the second TFTs(Thin Film Transistors) are connected to the dual gate lines, respectively. A data wire comprises as follows. Data lines(62) are extended in vertical direction by being insulated with the gate lines, and are formed every two pixel one by one. Source electrodes(65) of the first and the second TFTs are connected to the data lines, respectively. Drain electrodes(66) of the first and the second TFTs are separated from the source electrodes, and are faced with the source electrodes on the basis of the gate electrodes, respectively. Pixel electrodes(82) are connected to the dual gate lines and the data lines through the first and the second TFTs.

Description

A thin film transistor substrate for a liquid crystal display device and a method of manufacturing the same {A THIN FILM TRANSISTOR ARRAY PANEL FOR LIQUID CRYSTAL DISPLAY AND A METHOD FOR MANUFACTURING THE SAME}

The present invention relates to a thin film transistor substrate for a liquid crystal display device and a manufacturing method thereof.

The liquid crystal display is one of the most widely used flat panel display devices. The liquid crystal display includes two substrates on which electrodes are formed and a liquid crystal layer interposed therebetween, and rearranges the liquid crystal molecules of the liquid crystal layer by applying a voltage to the electrode. By controlling the amount of light transmitted.

Among the liquid crystal display devices, a liquid crystal display device having a thin film transistor for forming an electrode on each of two substrates and switching pixel voltages applied to the electrodes is used. Here, the thin film transistors are generally formed in a plurality of pixels arranged in a matrix form, and each pixel is formed with a pixel electrode to which an image signal is transmitted under the control of the thin film transistor. In addition, the thin film transistor substrate is connected to an output terminal of a gate driving integrated circuit, respectively, to supply a scan signal to control a pixel, and to be connected to an output terminal of a data driving integrated circuit, respectively, to supply an image signal and to intersect with the gate line. The data lines defining the pixels of are formed in a matrix form, and the gate lines and the data lines are connected to the pixel electrodes of the pixels through thin film transistors, respectively.

In this case, the number of gate lines is 480 when the liquid crystal display is VGA (video graphics array) class, but the number of data lines is 1920, which is four times the number of gate lines. In the case of WVGA class, the gate lines are Compared to 480, the number of data lines is 2400, which is five times the number of gate lines. This means that 4-5 times as much data driving integrated circuit as the gate driving integrated circuit is used in constructing the liquid crystal display.

However, in manufacturing such a liquid crystal display, in order to be competitive in the market, it is required to minimize manufacturing costs. Since the cost of data driving integrated circuits is higher than that of gate driving integrated circuits, it is necessary to minimize the number of data driving integrated circuits. need.

On the other hand, in order to improve the luminance of the display device, it is important to secure a high aperture ratio of the panel.

An object of the present invention is to provide a thin film transistor substrate for a liquid crystal display device having a minimum manufacturing cost.

In addition, another object of the present invention is to provide a thin film transistor substrate for a liquid crystal display device capable of ensuring a high aperture ratio.

1 is a layout view illustrating a structure of a thin film transistor substrate for a liquid crystal display according to a first embodiment of the present invention.

2 is an equivalent circuit diagram of a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a layout view illustrating a structure of a thin film transistor substrate for a liquid crystal display according to a second exemplary embodiment of the present invention.

To solve this problem, one data line is electrically connected to pixel electrodes of two neighboring pixels to transfer an image signal, and each pixel is connected to a different gate line.

More specifically, the thin film transistor substrate for a liquid crystal display according to the present invention extends in the horizontal direction on the upper and lower portions of the pixel, respectively, and a first gate gate and a second gate line respectively connected to the dual gate line for transmitting a scan signal. A gate wiring including the gate electrode of the thin film transistor is formed. Insulated from the gate line and extending in the vertical direction to define the pixel, the data line is formed for each of the two neighboring pixels, separated from the source electrode and the source electrode of the first and second thin film transistors connected to the data line, respectively. A data line including a drain electrode of the first and second thin film transistors facing the source electrode, respectively, is formed around the gate electrode. The pixel electrode connected to the dual gate line and the data line through the first and second thin film transistors is formed.

In this case, it is preferable that the data line is disposed at the center of the two pixels.

And a storage line overlapping the pixel electrode to form the storage capacitor, wherein the storage line is connected to the storage electrode line and the storage electrode line extending in the horizontal direction and formed in the vertical direction to overlap the edge side of the pixel electrode. It is preferable to include a sustain electrode.

In this case, the data lines may be formed in double, and the double data lines are preferably connected to each other through the connecting portion.

Here, the storage line may be formed of only the storage electrode line extending in the horizontal direction and overlapping the pixel electrode, and further comprising a conductive pattern for the storage capacitor connected to the drain electrode and the pixel electrode and overlapping the storage electrode line. .

Next, a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings so that a person skilled in the art may easily implement the present invention.

First, the structure of the thin film transistor substrate for a transmissive liquid crystal display according to the first embodiment of the present invention will be described in detail with reference to FIGS. 1 and 2.

1 is a layout view showing in detail the structure of a thin film transistor substrate for a transmissive liquid crystal display device according to a first embodiment of the present invention, Figure 2 is an equivalent circuit diagram of a thin film transistor substrate for a liquid crystal display device according to an embodiment of the present invention to be.

As shown in FIG. 1 and FIG. 2, the thin film transistor substrate for a liquid crystal display according to the first embodiment of the present invention may include a low resistance aluminum-based metal, molybdenum (Mo) or molybdenum-tungsten (MoW) alloy, and chromium. Gate wirings and data wirings including metals or conductors such as (Cr) and tantalum (Ta) are formed. The gate wiring includes a gate line 22 extending in the horizontal direction and a gate electrode 26 of the thin film transistors TFT1 and TFT2 connected to the gate line 22, and the gate wiring is formed at the end of the gate line 22. The gate pad may be connected to receive a gate signal from the gate driving integrated circuit and transfer the gate signal to the gate line 22. The data line is formed in a vertical direction and insulated from the gate line 22 to cross the data line 62 in the horizontal direction, the source electrode 65 of the thin film transistors TFT1 and TFT2 connected to the data line 62, A drain electrode 66 that is separate from the source electrode 65 and positioned opposite the source electrode 65 with respect to the gate electrode 26, wherein the data line is connected to one end of the data line 62 and the data The data pad may include a data pad that receives an image signal from the driver integrated circuit and transfers the image signal to the data line 62. In addition, each pixel P is electrically connected to the data lines 62, 65, and 66 through the drain electrodes 66 of the thin film transistors TFT1 and TFT2, and is formed of indium tin oxide (ITO) or indium zinc (IZO). A pixel electrode 82 made of a transparent conductive material such as oxide) or a material having excellent reflectance is formed. In this case, the thin film transistors TFT1 and TFT2 include a semiconductor layer 40 in which a channel is formed and overlaps the gate electrode 26, the source electrode 65, and the drain electrode 66, and the pixel electrode 82 Although it may be formed to overlap the gate line 22, when the storage capacitor is insufficient, as shown in the drawing, a storage capacitor wiring overlapping the pixel electrode 82 may be added. The storage capacitor wiring is connected to the storage electrode line 28 and the storage electrode line 28 extending in the horizontal direction, and are formed in each pixel P in the vertical direction to overlap the edge side of the pixel electrode 82. Sustain electrode 29;

In the thin film transistor substrate for a liquid crystal display according to the first exemplary embodiment of the present invention, the unit pixels P are disposed on both sides of the data lines 62, 65, and 66, and the gate lines 22 and 26. Is disposed on the upper and lower portions of the pixel P. In this case, each data line 62 is connected to the pixel electrode 82 of the two pixels P positioned on both sides thereof through the different thin film transistors TFT1 and TFT2, respectively, and the upper and The lower gate line 22 is a pixel electrode of the pixel P which is disposed on both sides of the data line 62 through each of the thin film transistors TFT1 and TFT2 including the gate electrode 26 connected to each other. Electrically connected with (82).

In the thin film transistor substrate for a liquid crystal display according to the exemplary embodiment of the present invention, when the pixel arrangement has a matrix arrangement of m × n, data signals are transmitted to two pixels for one data line 62. The number of data lines 62 decreases to n / 2, and the number of gate lines 22 doubles. Here, the number of gate lines 22 and data lines 62 is the total number of wirings, which means the number of output terminals of the gate and data driving integrated circuits. At this time, as described above, the number of gate lines and data lines of the WVGA class liquid crystal display device is 480 and 2400, respectively, and the number of charging wires is 2880. However, in the structure of the present invention, the number of gate lines 22 is doubled to 960, and the number of data lines 62 is reduced to half to 1200, so the total number of wirings is 2160. Therefore, in the structure according to the present invention, the total number of wirings of the gate line and the data line can be reduced by about 25% compared with the conventional technology. Therefore, the total number of driving integrated circuits can be reduced, and in particular, the number of expensive data driving integrated circuits can be significantly reduced, thereby minimizing the manufacturing cost of the liquid crystal display device.

On the other hand, since the data line 62 is formed one by two pixels, the aperture ratio of the pixel can be improved, and the sustain electrode 29 is formed between the pixel electrodes 82 between two neighboring data lines 62. Thus, the coupling effect generated between the pixel electrodes 82 is reduced.

In the method of manufacturing a thin film transistor substrate for a liquid crystal display device according to the first embodiment of the present invention, first, an aluminum-based conductive material having a low resistance is laminated on the substrate and patterned by a photolithography process using a photosensitive film to form a gate wiring ( 22, 26). In this case, the gate lines 22 and 26 may be formed of a single layer made of an aluminum-based conductive material, and may be formed of a multilayer including the single layer.

Subsequently, an insulating material such as silicon nitride (SiN _x ) is stacked on the substrate to form a gate insulating film covering the gate lines 22 and 26.

Subsequently, a gate insulating film on the gate electrode 26 is stacked and patterned by sequentially laminating and patterning a semiconductor, such as amorphous silicon, and a resistive contact layer made of a material such as n + hydrogenated amorphous silicon in which silicide or n-type impurities are heavily doped. The semiconductor layer 40 is formed over the 30. In this case, the semiconductor layer 40 may have various shapes instead of an island shape.

Subsequently, an aluminum-based conductive material having a low resistance on the substrate is stacked on the substrate and patterned by a photolithography process using a photosensitive film to form data lines 62, 65, and 66. In this case, the data lines 62, 65, and 66 may be formed of a single layer made of an aluminum-based conductive material, and may be formed of a multilayer including the single layer. Subsequently, the ohmic contact layer exposed with the data lines 62, 65, and 66 or the photoresist pattern for forming the same is etched.

Here, the semiconductor layer 40 and the data lines 62, 65, and 66 may be formed together in one photolithography process using photoresist patterns having partially different thicknesses.

Subsequently, a protective film covering the semiconductor layer 40 is formed by stacking an organic material or silicon nitride having low dielectric constant and excellent planarization characteristics. Subsequently, the protective layer is etched by a photolithography process using a photoresist pattern to form a contact hole exposing the drain electrode 66 to be connected to the pixel electrode 82. In this case, the gate insulating layer is also patterned together to form a contact hole that exposes the data pad and the gate pad to be connected to external circuits.

Next, a conductive material such as ITO or IZO is laminated and patterned using a mask to form a pixel electrode 82 connected to the drain electrode 66 through the contact hole of the protective film. In this case, an auxiliary gate pad and an auxiliary data pad connected to the gate pad 24 and the data pad 68 may be formed, respectively.

Next, unlike the first embodiment, a structure of a thin film transistor substrate for a reflective liquid crystal display device will be described.

3 is a layout view schematically illustrating a structure of a thin film transistor substrate for a reflective liquid crystal display according to an exemplary embodiment of the present invention.

As shown in Fig. 3, most of the structure is the same as that of the first embodiment.

However, unlike the transmissive type, since the aperture ratio of the pixel does not have to be taken into consideration, the data lines 62 are formed in double, and they are connected through the connecting portion 63, and the sustain wiring is held across the center of the pixel in the horizontal direction. It consists of the electrode 28 only. On the same layer as the data lines 62, 65, and 66, a conductive capacitor pattern 68 is formed, and the drain electrode 66 extends to be connected to the conductive capacitor pattern 68. In addition, the pixel electrode 82 used as a reflector and electrically connected to the conductive capacitor conductor 68 through the contact hole of the protective film is formed to overlap the gate line 22 and the data line 62. .

In the structure according to the second exemplary embodiment of the present invention, the data line 62 is formed in double, so that disconnection of the data line 62 can be prevented.

In the method of manufacturing a reflective thin film transistor substrate for a liquid crystal display device, in order to minimize the coupling effect occurring between the gate line 22 and the data line 62 and the pixel electrode 82 which overlap each other, It is preferable to form a thick protective film interposed therebetween with an organic material having a low dielectric constant. In addition, the reflective plate 82 is preferably formed of an aluminum-based or silver-based metal having a high reflectance, and a protective film formed below the reflective plate 82 is formed to have irregular irregularities in order to improve the reflection efficiency of the reflective plate 82. .

As described above, according to the present invention, the manufacturing cost of the liquid crystal display device is minimized by reducing the number of wiring lines including the gate lines and the data lines, thereby reducing the number of gate and data driving integrated circuits, particularly the number of expensive data driving integrated circuits. can do. In addition, the aperture ratio of the pixel can be maximized by transferring the image signal to the two pixels through one data line.

Claims (8)

A gate line including a double gate line extending in a horizontal direction and transmitting a scan signal to upper and lower portions of the pixel, and gate electrodes of first and second thin film transistors respectively connected to the double gate line; A data line which is insulated from the gate line and extends in a vertical direction and is formed for each of the two neighboring pixels, a source electrode of the first and second thin film transistors connected to the data line, and separated from the source electrode A data line including drain electrodes of the first and second thin film transistors facing the source electrode, respectively, around the gate electrode; A pixel electrode connected to the dual gate line and the data line through the first and second thin film transistors Thin film transistor substrate for a liquid crystal display device comprising a. In claim 1, And the data line is disposed at the center of the two pixels. In claim 2, And a sustain wiring overlapping the pixel electrode to form a storage capacitor. In claim 3, And the storage wiring line includes a storage electrode line extending in a horizontal direction and a storage electrode connected to the storage electrode line in a vertical direction and overlapping an edge portion of the pixel electrode. In claim 4, The sustain electrode is a thin film transistor substrate for a liquid crystal display device provided to cover the interval between the pixel electrode of the adjacent pixels. In claim 2, The data line is formed in a double, the double data line is a thin film transistor substrate for a liquid crystal display device is connected to each other through a connecting portion. In claim 6, And a storage electrode line extending in the horizontal direction and overlapping the pixel electrode. In claim 7, The thin film transistor substrate of claim 1, further comprising a conductive pattern for a storage capacitor connected to the drain electrode and the pixel electrode and overlapping the storage electrode line.