KR100333984B1 - Liquid crystal display and manufacturing method thereof - Google Patents

Abstract

A gate wiring is formed on an insulated substrate, and a silicon oxide layer heavily doped with a gate insulating film, an amorphous silicon layer, phosphorus (P), etc. is sequentially deposited and patterned on the gate wiring to form a semiconductor layer and a contact layer, and then chromium is deposited. And patterning to form data wiring. The contact layer between the source electrode and the drain electrode is etched using the data line as an etch stop layer, and silicon nitride is thinly deposited to form a protective insulating film, and the color filter layers are stacked and patterned to form red, blue, and green color filters. Next, an organic insulating layer is stacked and patterned to form a contact hole for exposing the gate pad, the data pad, and the drain electrode, and ITO is deposited and patterned to form a pixel electrode having an opening pattern, an auxiliary gate pad, and an auxiliary data pad to form a thin film transistor. Prepare the substrate. In this way, the data wiring can be formed of a single layer made of a material having high chemical resistance, so that the process can be simplified, and the width of the black matrix of the top plate can be narrowed instead of using the data wiring as a light blocking film, thereby increasing the aperture ratio. Since the brightness is improved through this, the double brightness enhanced film (DBEF) used to improve the brightness can be omitted.

Description

Liquid crystal display device and its manufacturing method {LIQUID CRYSTAL DISPLAY AND MANUFACTURING METHOD THEREOF}

The present invention relates to a liquid crystal display device, and more particularly, to a thin film transistor substrate for a liquid crystal display device.

In general, a liquid crystal display device injects a liquid crystal material between an upper substrate on which a common electrode, a color filter, and the like are formed, and a lower substrate on which a thin film transistor and a pixel electrode are formed. By applying a different potential to form an electric field to change the arrangement of the liquid crystal molecules, and through this to control the light transmittance is a device that represents the image.

The upper substrate for the liquid crystal display device is a transparent conductive material such as a red, blue and green color filter on the transparent substrate and a black matrix and indium tin oxide (ITO) formed between the color filters. It comprises a common electrode made up. The common electrode may be formed directly on the color filter or the black matrix. However, when a predetermined pattern is formed on the common electrode to form a fringe field, the lower color filter is etched in the etching process for common electrode patterning. In order to prevent damage, an organic insulating layer is laminated on the color filter and a common electrode is formed thereon.

However, after the organic insulating layer is stacked between the common electrode and the color filter, the afterimage phenomenon is intensified, and since the common electrode signal is transmitted only through the patterned common electrode, the resistance experienced by the signal increases. As a result, as the common electrode voltage moves away from the entry point, the common electrode voltage drops significantly, and the common electrode voltage has different values according to positions, which makes it difficult to control flicker. This problem becomes more serious as the screen becomes larger.

In the lower substrate of the liquid crystal display, the gate line and the data line are insulated from each other and cross each other, the thin film transistor is connected to the gate line and the data line, and the pixel electrode is connected to the thin film transistor. The thin film transistor functions as a switch that is opened and closed by a scan signal of a gate line, and transmits an image signal transmitted along the data line to the pixel electrode when the switch is closed.

However, as the screen becomes larger, the problem of delay-capacitance (RC) delay of the signal becomes serious and it is necessary to reduce the resistance of the gate line or the data line to solve the problem. However, if the width of the gate line or data line is increased to decrease the resistance, the aperture ratio decreases by that amount. Therefore, instead of increasing the line width, the signal lines are doubled. That is, one layer is formed of a material having low resistance, such as aluminum-neodynium, and the other layer is formed of a material that is chemically stable and has excellent contact properties with other materials, such as chromium. However, in the case of the data line, the aluminum-neodymium layer having a low resistance is damaged by an ITO etchant in the process of patterning a pixel electrode made of ITO later, so that the chromium layer surrounds the aluminum-neodynium layer in order to prevent this. It is common to form data lines. However, in order to form a data line with such a structure, first, the chromium layer and the aluminum-neodynium double layer are deposited, and the aluminum-neodynium layer is patterned through a photolithography process. Photo should be etched. That is, two etching processes are required only for forming the data lines, resulting in a decrease in productivity of the liquid crystal display.

An object of the present invention is to improve the productivity of a liquid crystal display device.

Another object of the present invention is to improve the aperture ratio of a liquid crystal display device.

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

2 and 3 are cross-sectional views taken along lines II-II 'and III-III' of FIG. 1, respectively.

4A is a layout view of a substrate in an intermediate process of manufacturing a thin film transistor substrate according to an embodiment of the present invention;

4B and 4C are cross-sectional views taken along lines IVb-IVb 'and IVc-IVc' of FIG. 4A, respectively.

5A is a layout view of a substrate in a next step of FIGS. 4A to 4C during a process of manufacturing a thin film transistor substrate according to an embodiment of the present invention;

5B and 5C are cross-sectional views taken along lines Vb-Vb 'and Vc-Vc' of FIG. 5A, respectively.

6A is a layout view of the substrate in the next step of FIGS. 5A-5C,

6B and 6C are cross-sectional views taken along lines VIb-VIb 'and VIc-VIc' of FIG. 6A, respectively.

FIG. 7A is a layout view of a substrate in the next step of FIGS. 6A-6C,

7B and 7C are cross-sectional views taken along the lines 'b-'b' and 'c-'c' of FIG. 7A, respectively.

In order to solve this problem, the present invention forms a color filter on the thin film transistor.

Specifically, a gate wiring including a gate line extending in a first direction, a gate pad connected to one end of the gate line, and a gate electrode that is a branch of the gate line is formed on an insulating substrate, and the contact is formed to expose the gate pad on the gate wiring. A first insulating film having a sphere is formed, and a semiconductor layer in which part of the gate electrode on the first insulating film is overlapped is formed. A contact layer is formed on both sides of the semiconductor layer with the gate electrode at the center, and is connected to one end of the data line and the data line intersecting the source electrode, the drain electrode, and the gate line on the contact layer and connected to the source electrode. After forming a data line including a data pad, a color filter layer is formed on the data line. Next, a second insulating film having a contact hole exposing the drain electrode, the data pad and the gate pad is formed on the color filter layer, and a pixel electrode connected to the drain electrode through the contact hole is formed on the second insulating film to form a thin film for a liquid crystal display device. The transistor substrate is formed.

Here, a protective insulating layer may be further formed below the color filter to cover the semiconductor layer, and an auxiliary gate pad and an auxiliary data pad covering the gate pad and the data pad may be further formed on the second insulating layer. The second insulating film may be formed of a photosensitive organic insulating material, and the gate wiring and the data wiring may be formed of a double layer of aluminum and chromium or aluminum-neodynium and chromium, and the data line may have a width of between 15 μm and 25 μm. It can be formed to have. The pixel electrode may be formed to have an opening pattern.

The liquid crystal display may be manufactured by arranging the thin film transistor substrate and the second substrate on which the common electrode is formed to face each other and injecting and sealing a liquid crystal material therebetween.

In this case, a black matrix may be further formed between the second substrate and the common electrode, and the pixel electrode and the common electrode may form an opening pattern such that the opening pattern of the pixel electrode and the opening pattern of the common electrode overlap each other. It can be made to divide into areas.

A thin film transistor substrate having such a structure includes forming a gate wiring including a gate pad and a gate line on an insulating substrate, sequentially laminating a first insulating film, a semiconductor layer, and a contact layer on the gate wiring, and forming a contact layer and a semiconductor layer. Forming a contact layer pattern and a semiconductor layer pattern under the photolithography, forming a data line including a source electrode and a drain electrode and a data pad formed on the contact layer; and a color filter layer on a substrate including the data line. Forming a second insulating film on the color filter layer, and forming a pixel electrode on the second insulating film.

In this case, the method may further include forming a protective insulating layer after forming the data line, and in the forming of the pixel electrode, the auxiliary gate pad covering the gate pad and the auxiliary data pad covering the data pad may be formed together. Can be. The second insulating film may be formed of a photosensitive organic material, and the protective insulating film may form silicon nitride.

Next, a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the drawings.

1 is a layout view of a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention, and FIGS. 2 and 3 are cross-sectional views taken along lines II-II 'and III-III' of FIG. 1, respectively.

First, a gate made of a metal or a conductor such as aluminum (Al) or aluminum alloy (Al alloy), molybdenum (Mo) or molybdenum-tungsten (MoW) alloy, chromium (Cr), tantalum (Ta) or the like on the insulating substrate 10. Wiring is formed. The gate wiring is connected to the scan signal line or the gate line 22 extending in the horizontal direction and the gate line 22 and the gate pad 24 and the gate which receive the scan signal from the outside and transmit the scan signal to the gate line 22. A gate electrode 26 of the thin film transistor that is part of the line 22.

The gate wirings 22, 24, and 26 may be formed in a single layer, but may also be formed in a double layer or a triple layer. In the case of forming more than two layers, it is preferable that one layer is formed of a material having a low resistance and the other layer is formed of a material having good contact properties with other materials, and a double layer of Cr / Al (or Al alloy) or Al / Mo Bilayers are an example.

A gate insulating film 30 made of silicon nitride (SiN _x ) is formed on the gate wirings 22, 24, and 26 to cover the gate wirings 22, 24, and 26.

A semiconductor pattern 40 made of a semiconductor such as hydrogenated amorphous silicon is formed on the gate insulating layer 30, and an amorphous doped with an n-type impurity such as phosphorus (P) is heavily doped on the semiconductor 40. An ohmic contact layer pattern or intermediate layer patterns 55 and 56 made of silicon are formed.

Data lines made of a conductive material such as Cr are formed on the contact layer patterns 55 and 56. The data line is a thin film transistor which is a branch of the data line 62 formed in the vertical direction, the data pad 64 connected to one end of the data line 62 to receive an image signal from the outside, and the data line 62. A drain electrode of the thin film transistor including a data line portion formed of the source electrode 65 of the thin film transistor, and separated from the data line portions 62, 64, and 65 and positioned opposite to the source electrode 65 with respect to the gate electrode 26. Also includes (66). In addition, the conductive capacitor conductor 67 for the storage capacitor positioned on the gate line 22 and overlapping is also formed of the same material as the data lines 62, 64, 65, and 66. The conductive pattern 67 for the storage capacitor is connected to the pixel electrode 71 to be described later to form a storage capacitor. However, the conductive capacitor pattern 67 for the storage capacitor may not be formed if the storage capacitor of sufficient size can be obtained only by the superposition of the pixel electrode 71 and the gate line 22.

At this time, the data line 62 can be made to have a considerably wider width than about the conventional (6 micrometers-7 micrometers) within about 20 micrometers. Therefore, the resistance can be made sufficiently low even if the data lines 62, 64, 65, and 66 are not doubled. Of course, if necessary, the data lines 62, 64, 65, and 66 may be formed in duplicate by using a material having a low resistance such as aluminum-neodymium. The width of the data lines 62, 64, 65, and 66 can be widened because the color filter is formed on the thin film transistor substrate as described later. In this case, the data lines 62, 64, 65, and 66 are black. It also functions as a matrix.

On the data wirings 62, 64, 65, 66 and the conductor pattern 67 for the storage capacitor, a protective insulating film 91 made of silicon nitride is formed over the entire substrate. This insulating film is intended to prevent the channel portion semiconductor layer 40 of the thin film transistor from coming into direct contact with the color filter 90 to prevent contamination of the channel portion.

Red, blue and green color filters 90 are formed on the protective insulating film 91. In the color filter 90, red, blue, and green colors are alternately arranged for each pixel area defined as a region where two neighboring gate lines 22 and data lines 62 intersect each other. In the color filter 90, a contact hole 81 for exposing the drain electrode and a contact hole 82 for exposing the conductive pattern 67 for the storage capacitor are formed.

On the color filter 90, an organic insulating film 80 is stacked over the entire surface of the substrate 10. In the organic insulating layer 80, the contact holes 83 and 84 exposing the gate pad 24 and the data pad 64, the contact hole 81 exposing the drain electrode 66 and the conductor pattern 67 for the storage capacitor are formed. The contact hole 82 exposing) is formed. Here, the organic insulating layer 80 may be formed of a photosensitive organic material, and in this case, the organic insulating layer 80 for forming the contact holes 81, 83, and 84 may be patterned only through an exposure and development process.

On the organic insulating layer 80, the pixel electrode 71 and the gate pad 24, which are connected to the drain electrode 66 and the conductive capacitor 67 for the storage capacitor and have an opening pattern, are formed through the contact holes 81 and 82. ) And an auxiliary data pad 74 covering the auxiliary gate pad 73 and the data pad 64. The pixel electrode 71 is physically and electrically connected to the drain electrode 66 through the contact hole 81 to receive an image signal from the thin film transistor to generate an electric field together with the electrode of the upper plate, and is made of a transparent conductive material such as ITO. . The pixel electrode 71 is also connected to the conductive capacitor pattern 67 to form a storage capacitor between the conductive capacitor pattern 67 and the gate line 22 overlapping the conductive capacitor pattern 67. On the other hand, the auxiliary gate pad 84 and the auxiliary data pad 86 serve to complement the contact between the gate pad 24 and the data pad 64 and an external circuit, and to complement the pads 24 and 64, respectively. do. The opening pattern formed in the pixel electrode 71 is used to form fringe fields in various directions by dividing one pixel into a plurality of regions together with the opening pattern (dotted line) formed in the common electrode of the upper plate. The viewing angle can be improved.

By forming the color filter together on the thin film transistor substrate which is the lower plate as described above, only the black matrix and the common electrode having a narrower width than the conventional one are formed on the upper plate. However, chromium, which is used as a black matrix, is chemically stable and is not significantly affected by ITO etchant, and thus can be formed by directly contacting ITO without using an organic insulating layer. Since chromium is a conductive material, it can contribute to the transmission of a common electrode signal. As the common electrode voltage moves away from the point of entry, the drop can be reduced. In addition, by making the data lines 62, 64, 65, and 66 function as black matrices, the width of the upper black matrices can be greatly reduced, and eventually the aperture ratio increases.

In addition, since the color filter 90 and the organic insulating film 80 are formed thick between the pixel electrode 71 and the data line 62, the parasitic capacitance between the two is reduced.

Next, a method of manufacturing a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to FIGS. 3A to 7C and FIGS. 1 to 3.

First, as shown in FIGS. 4A to 4C, a conductive layer such as chromium (Cr) and aluminum-neodymium (Al-Nd) is continuously deposited by a sputtering method and patterned by a photolithography method, thereby providing a substrate 10. A gate wiring including a gate line 22, a gate pad 24, and a gate electrode 26 is formed thereon. Subsequently, the amorphous silicon layer heavily doped with the gate insulating film 30, the amorphous silicon layer, the phosphorus (P), or the like is continuously deposited and patterned by using a chemical vapor deposition method, and a portion thereof is overlapped with the gate electrode 26. The semiconductor layer 40 and the contact layer 50 pattern are formed to be.

Next, as illustrated in FIGS. 5A to 5C, the data line 62, the data line 62, the data pad 64, and the source electrode 65 are deposited by depositing and patterning a chemically stable conductive material such as chromium or molybdenum. And a data wiring including a drain electrode, and at the same time, a conductor pattern 67 for a storage capacitor is also formed. At this time, the width of the data wiring is formed to be about 20 μm wide to serve as a light blocking film. The data line may be formed of a double layer of aluminum or aluminum-neodynium and chromium or aluminum and molybdenum as before. Subsequently, the exposed contact layer 50 between the source electrode 65 and the drain electrode 66 is etched away.

Next, as shown in FIGS. 6A to 6C, silicon nitride or the like is deposited on the entire surface of the substrate 10 by sputtering or the like to form a protective insulating film 91, and the color filter layer 90 is formed on the protective insulating film 91. Form. The color filter layer 90 is formed such that red, blue, and green color filters are alternately arranged by repeating a process of applying, exposing and developing a photosensitive material.

Next, as shown in FIGS. 7A to 7C, the organic insulating film 80 is stacked and patterned on the color filter layer 90 by spin coating or the like to form the gate pad 24 and the data pad 64. The contact holes 81, 82, 83, and 84 that expose the drain electrode 66 and the conductive pattern 67 for the storage capacitor are formed. At this time, the protective insulating film 91 formed under the color filter layer 90 is also patterned. In addition, the organic insulating layer 80 may be formed of a photosensitive material. In this case, the organic insulating layer 80 may be patterned only by exposure and development through a mask, and the protective insulating layer 91 may etch the organic insulating layer 80. Patterning may be performed.

Finally, as shown in FIGS. 1 to 3, a transparent conductive material such as ITO is deposited and patterned by a photolithography method, thereby forming the pixel electrode 71, the auxiliary gate pad 73, and the auxiliary data pad 74 having an opening pattern. ). In this case, as an etching method, a dry etching method as well as a wet etching method may be used. This is possible because the organic insulating layer is formed on the lower side. When the protective layer is formed of silicon nitride only, only a dry etching method is allowed.

When the lower substrate is formed in the above manner, only the black matrix and the common electrode need be formed on the upper substrate. That is, a double layer of chromium and chromium oxide (CrOx) is formed on the transparent substrate and patterned by photolithography to form a black matrix. The black matrix may also be formed using an organic material. Next, a transparent conductive material such as ITO is laminated and patterned to form a common electrode having an opening pattern.

All of the above manufacturing process can be carried out in the equipment used in the prior art does not require a separate equipment.

If the liquid crystal display device is manufactured with the above structure and method, the data wiring can be formed in a single layer made of a material having high chemical resistance, so that the process can be simplified, and instead of using the data wiring as the light blocking film, Since the width of the matrix can be narrowed, the aperture ratio can be increased, and since the brightness is improved, the double brightness enhanced film (DBEF) used for brightness enhancement can be omitted.

Claims (23)

Insulated substrate (correction), A gate line formed on the insulating substrate and extending in a first direction, a gate pad connected to one end of the gate line, and a gate wire electrically connected to the gate line; A first insulating film formed on the gate wiring and having a contact hole for exposing the gate pad, A semiconductor layer formed on the first insulating layer and partially overlapping the gate electrode; A contact layer formed on the semiconductor layer and separated on both sides of the gate electrode; A source electrode formed on one side of the contact layer, a drain electrode formed on the other side of the contact layer, a data line intersecting with the gate line and connected to the source electrode and one end of the data line. A data wiring comprising a connected data pad, A color filter layer formed on the data line, A second insulating film formed on the color filter layer and having a contact hole for exposing the drain electrode, the data pad, and the gate pad; A pixel electrode formed on the second insulating film and connected to the drain electrode through the contact hole; Thin film transistor substrate for a liquid crystal display device comprising a. In claim 1, And a protective insulating layer formed under the color filter and covering the semiconductor layer. The method of claim 1 or 2, And an auxiliary gate pad and an auxiliary data pad formed on the second insulating layer and covering the gate pad and the data pad, respectively. The method of claim 1 or 2, The second insulating film is a thin film transistor substrate for a liquid crystal display device made of an organic insulating material. In claim 4, The second insulating film is a photosensitive material thin film transistor substrate for a liquid crystal display device. The method of claim 1 or 2, The gate wiring is a thin film transistor substrate for a liquid crystal display device formed of a double layer of aluminum and chromium or aluminum-neodynium and chromium. The method of claim 1 or 2, The data line has a width of between 15 μm and 25 μm. The method of claim 1 or 2, And the data line is formed of a double layer of aluminum and chromium or aluminum-neodynium and chromium. The method of claim 1 or 2, And the pixel electrode has an opening pattern. The thin film transistor substrate of claim 1, A second substrate facing the thin film transistor substrate, A common electrode formed on one surface of the second substrate, A liquid crystal material injected between the thin film transistor substrate and the second substrate Liquid crystal display comprising a. In claim 10, And a black matrix formed between the second substrate and the common electrode. The liquid crystal display of claim 11, wherein the pixel electrode and the common electrode have an opening pattern, and the opening pattern of the pixel electrode and the opening pattern of the common electrode overlap to divide the pixel area into a plurality of areas. Forming a gate wiring including a gate pad and a gate line on the insulating substrate, Sequentially depositing a first insulating film, a semiconductor layer, and a contact layer on the gate wiring; Photo-etching the contact layer and the semiconductor layer to form a contact layer pattern and a semiconductor layer pattern thereunder; Forming a data line including a source electrode, a drain electrode, and a data pad formed on the contact layer; Forming a color filter layer on the substrate including the data line; Forming a second insulating film on the color filter layer; Forming a pixel electrode on the second insulating layer Method of manufacturing a thin film transistor substrate comprising a. In claim 13, And forming a protective insulating film after forming the data line. The method of claim 13 or 14, Forming an auxiliary gate pad covering the gate pad and an auxiliary data pad covering the data pad in the forming of the pixel electrode. The method of claim 13 or 14, And the second insulating film is made of an organic insulating material. The method of claim 16, The second insulating film is a method of manufacturing a thin film transistor substrate made of a photosensitive material. The method of claim 14, The protective insulating film is a method of manufacturing a thin film transistor substrate made of silicon nitride. (Newly formed) insulation board, A gate line formed on the insulating substrate and extending in a first direction, a gate pad connected to one end of the gate line, and a gate wire electrically connected to the gate line; A first insulating film formed on the gate wiring and having a contact hole for exposing the gate pad, A semiconductor layer formed on the first insulating layer and partially overlapping the gate electrode; A contact layer formed on the semiconductor layer and separated on both sides of the gate electrode; A source electrode formed on one side of the contact layer, a drain electrode formed on the other side of the contact layer, a data line intersecting with the gate line and connected to the source electrode and one end of the data line. A data wiring comprising a connected data pad, A conductive pattern for a storage capacitor formed on the gate line, A second insulating film formed over the data line and having a contact hole for exposing the drain electrode, the data pad, the gate pad, and the conductive pattern for the storage capacitor; A pixel electrode formed on the second insulating layer and electrically connected to the drain electrode and the conductive pattern for the storage capacitor through the contact hole, and at least partially overlapping the data line; Thin film transistor substrate for a liquid crystal display device comprising a. (New) from paragraph 19 And the second insulating film is an organic insulating film. (Newly established) in 19 or 20, And an auxiliary gate pad and an auxiliary data pad formed on the second insulating layer and covering the gate pad and the data pad, respectively. (New) from paragraph 21, The gate wiring is a thin film transistor substrate for a liquid crystal display device formed of a double layer containing aluminum or aluminum alloy. (New) from paragraph 21, The thin film transistor substrate of claim 2, further comprising a color filter layer under the second insulating layer.