KR20080083516A - Liquid crystal display and fabrication process thereof - Google Patents

Abstract

An LCD(Liquid Crystal Display) device and a manufacturing method thereof are provided to form a transparent conductive film on a passivation layer and form an opening by exposing and developing the passivation layer by using transmissive properties of the transparent conductive film, thereby simplifying a process. In a substrate, plural pixel areas are defined. A gate line(203) and a common line(205) are formed on the substrate. The gate line includes a gate pad(203P) and a gate electrode(203G). The common line is spaced from the gate line as much as a predetermined interval, and includes a common electrode(205C). A gate insulating layer(207) is formed on the substrate having the common line. A data line(209) is formed on the gate insulating layer as crossing the gate line, and has a data pad(209P) and source/drain electrodes(209S,209D). A storage electrode is formed on the gate insulating layer to be overlapped with the common line. A passivation layer is formed on the substrate having the storage electrode, and comprises a photo acryl film for exposing the gate pad, the data pad and the storage electrode. A pixel electrode(217) is formed on the passivation layer, and connected with transparent conductive film patterns connected with the gate and data pads and the storage electrode. The transparent conductive film pattern is interposed between the passivation layer and the pixel electrode.

Description

Liquid crystal display device and its manufacturing method {LIQUID CRYSTAL DISPLAY AND FABRICATION PROCESS THEREOF}

1 is a cross-sectional view of a transverse electric field type liquid crystal display device according to the prior art.

2 is a plan view of a transverse electric field type liquid crystal display device according to the present invention.

3A to 3D are cross-sectional views showing processes taken along lines A-A ', B-B', C-C ', and D-D' of FIG. 2.

The present invention relates to a liquid crystal display device and a method for manufacturing the same, and more particularly to a transverse electric field type liquid crystal display device and a method for manufacturing the same that can reduce the number of masks.

As is generally known, with the development of the electronics industry, display devices, which have been limitedly used in TV CRTs, are widely used in personal computers, laptops, wireless terminals, automobile dashboards, electronic displays, and the like. As image information can be transmitted, the importance of next-generation display devices that can process and implement them is increasing.

Such next-generation display devices should be able to realize light and small, high brightness, large screen, low power consumption, and low cost, and one of them has recently attracted attention.

The liquid crystal display (LCD) has excellent display resolution than other flat panel display devices and exhibits a response speed that is higher than that of a CRT when a moving image is realized.

One of the liquid crystal display devices currently used is a twisted nematic (TN) type liquid crystal display device. The twisted nematic method is a method of driving the liquid crystal director by installing electrodes on two substrates, arranging the liquid crystal directors to be twisted by 90 °, and then applying a voltage to the electrodes. However, the TN (twisted nematic mode) liquid crystal display device has a big disadvantage that the viewing angle is narrow.

Recently, researches on liquid crystal display devices employing various new methods have been actively conducted to solve the narrow viewing angle problem. In this method, an in-plane switching mode (IPS) or an OCB is used. Optically compensated birefrigence mode. Among these, the transverse electric field type liquid crystal display device forms two electrodes on the same substrate in order to drive the liquid crystal molecules in a horizontal state with respect to the substrate, and applies a voltage between the two electrodes to apply the voltage to the substrate. Generate an electric field in the direction. In other words, the long axis of the liquid crystal molecules does not stand on the substrate. For this reason, the change of the birefringence of the liquid crystal with respect to the visual direction is small, and the viewing angle characteristic is much superior to the conventional TN type liquid crystal display device.

Hereinafter, a structure and a manufacturing method of a transverse electric field type liquid crystal display device according to the related art will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a transverse electric field type liquid crystal display device according to the prior art. Hereinafter, a method of manufacturing a transverse electric field type liquid crystal display device according to the related art will be briefly described with reference to FIG. 1.

As shown in FIG. 1, first, a metal is deposited on a substrate 118 and then patterned to form a gate wiring (not shown) and a common wiring (not shown). In this case, the gate line includes a gate pad 109P and a gate electrode 109G branched from the gate line. In addition, the common wiring includes a common electrode 109C. (1st photo mask process)

 The semiconductor layer 123 including the active layer 123a and the ohmic contact layer 123b is interposed between the substrate including the gate electrode 109G to form a matrix structure. Wiring (not shown) is formed. In this case, the data line includes a source electrode 125S, a drain electrode 125D, and a data pad 125P of the thin film transistor. The active layer 123a between the source electrode 125S and the drain electrode 125D corresponds to a channel region. (2nd photo mask process)

Thereafter, a passivation layer 129 is formed on the substrate having the source electrode 125S and the drain electrode 125D. In this case, when the photoacryl film is applied as the passivation layer 129, the parasitic voltage between the data line and the pixel electrode may be reduced to realize high brightness through a high aperture ratio, and the holding power may be reduced. However, when the protective film, which is a photoacryl film, is in direct contact with the channel region of the thin film transistor, the device characteristics are deteriorated. Thus, the first silicon nitride film 127 is formed under the photoacrylic film. That is, the first silicon nitride layer 127 is a channel protection layer, and may prevent direct contact between the channel region of the thin film transistor and the photoacrylic layer 129, thereby improving device characteristics of the channel region.

Subsequently, the photoacryl film and the first silicon nitride film are selectively patterned to form a first opening H1 connected to the drain electrode 125D. At this time, the gate pad 109P and the data pad 109C are also exposed while forming the first opening. (3rd photo mask process)

Next, a second silicon nitride film 131 is formed on the substrate having the first opening H1. In this case, the second silicon nitride film 131 is to prevent the liquid crystal from being deviated when the liquid crystal is in direct contact with the photo acrylic film in a subsequent process. As described above, by having a protective film structure composed of a first acrylic film and a second silicon nitride film disposed on the upper and lower portions of the photoacryl film and the photoacryl film, two photomask processes are involved in patterning the protective film.

Thereafter, the second silicon nitride layer is patterned to form openings in the gate pad, the data pad, the storage electrode, and the drain electrode 125D. (4th photo mask process)

Subsequently, a transparent conductive film is formed on the substrate having the opening. Next, the transparent conductive layer is patterned to form a transparent conductive layer pattern 133P1 and 133P2 connected to the gate pad and the data pad, and a pixel electrode electrically connected to the storage electrode 109C and the drain electrode 125D. 133. (Fifth photo mask process)

 Thereafter, a first alignment layer (not shown) is formed on the entire surface of the substrate having the pixel electrode 133 to complete the manufacture of the array substrate.

As described above, five masks (gate wiring, data wiring, protective film first opening, protective film second opening, and pixel electrode formation) are used for array substrate fabrication of a transverse electric field type liquid crystal display device. The number of masks here represents the number of processes for manufacturing the array substrate. In this case, the photolithography process involves various processes such as cleaning, coating of the photoresist film, exposure and development, and etching. Therefore, even if a single photo-etching process is shortened significantly, manufacturing time can be significantly reduced, manufacturing cost can be reduced, and a defect rate is reduced. Therefore, a method of manufacturing an array substrate by reducing the number of masks should be studied.

Accordingly, an object of the present invention is to provide a liquid crystal display device and a method of manufacturing the same that can simplify the process by reducing the number of photo mask.

In order to achieve the above object, the liquid crystal display device according to the present invention comprises a substrate in which a plurality of pixel areas are defined; A gate wiring formed on the substrate, spaced apart from the gate wiring at a predetermined interval, and provided with a gate pad and a gate electrode; A gate insulating film formed on the substrate having the common wiring; A data wiring formed on the gate insulating film to intersect the gate wiring and including a data pad and a source electrode and a drain electrode; The storage electrode formed on the gate insulating layer to overlap the common wiring; A protective film formed on a substrate having the storage electrode and comprising a photo acrylic film exposing the gate pad, the data pad, and the storage electrode; A pixel electrode formed on the passivation layer, the transparent conductive film patterns connected to the gate pad and the data pad, and the pixel electrode connected to the storage electrode; It includes a transparent conductive film pattern interposed between the protective film and the pixel electrode.

The gate wiring and the common wiring are formed of the same film, and preferably formed of at least one of Al, Cu, Ta, Ti, Mo, Mo alloy, and Al alloy.

The data line and the storage electrode may be formed of the same layer, and may be formed of at least one of Al, Cu, Ta, Ti, Mo, Mo alloy, and Al alloy.

And a channel passivation layer interposed between the gate insulating layer and the passivation layer. In this case, the channel protective film is a liquid crystal display device, characterized in that the silicon nitride film.

The semiconductor device may further include a transparent conductive film pattern interposed between the pixel electrode including the conductive film patterns and the passivation layer.

The conductive layer patterns and the pixel electrode may be formed of at least one of Ti, Mo, and Mo-Ti alloys.

A method of manufacturing a liquid crystal display device according to the present invention includes forming a gate electrode, a gate wiring with a gate pad, and a common wiring with a common electrode on a substrate, and a gate insulating film on the substrate with the common wiring. Forming a step. Forming a data electrode crossing the gate line and a storage electrode overlapping the common line on the gate insulating layer, wherein the data line includes a source electrode, a drain electrode, and a data pad, and on the substrate having the data line. Sequentially forming a protective film and a transparent conductive film formed of a photo acrylic film on the substrate, and patterning the transparent conductive film and the protective film to expose the gate pad, the data pad, and the storage electrode, respectively. Forming a conductive film, forming a conductive film on the substrate having the first, second and third openings, and patterning the conductive film and the remaining transparent conductive film to connect the gate pad and the data pad. Forming a pixel electrode connected to the patterns and the storage electrode.

The gate wiring and the common wiring are formed of the same film, and preferably formed of at least one of Al, Cu, Ta, Ti, Mo, Mo alloy, and Al alloy.

The data line and the storage electrode may be formed of the same layer, and may be formed of at least one of Al, Cu, Ta, Ti, Mo, Mo alloy, and Al alloy.

The method may further include forming a channel passivation layer between the gate insulating layer and the passivation layer. In this case, the channel protective film is preferably formed of a silicon nitride film.

The protective film is preferably formed by a spin coating process.

Before forming the transparent conductive film, the method further comprises the step of soft baking the protective film.

Forming the first, second and third openings by selectively exposing and developing the transparent conductive film and the protective film on which the soft baking is completed; The method may further include hard baking the protective film on which the development is completed.

The transparent conductive film is preferably formed of an ITO film.

The conductive layer patterns and the pixel electrode may be formed of the same layer, and at least one of Ti, Mo, and Mo-Ti alloys.

(Example)

Hereinafter, with reference to the accompanying drawings will be described an embodiment according to the present invention.

2 is a plan view of a transverse electric field type liquid crystal display device according to the present invention. 3 is a cross-sectional view for each process showing the cut surface of the line II of FIG. 2. Hereinafter, a method of manufacturing a transverse electric field type liquid crystal display device according to the present invention will be described with reference to FIGS. 2 and 3A to 3D.

As shown in FIGS. 2 and 3A, a first metal film is formed on the substrate 201. The first metal film uses at least one of Al, Cu, Ta, Ti, Mo, Mo alloy and Al alloy. Subsequently, the first metal film is patterned to form a gate wiring 203 and a common wiring 205. In this case, the gate line includes a gate pad 203P and a gate electrode 203G branched from the gate line 203. In addition, the common wiring 205 includes common electrodes 205C arranged to be spaced apart at regular intervals in a direction perpendicular to the common wiring. In this case, the gate wiring 203 and the common wiring 205 may be formed by a photolithography process using a resist pattern. (1st photo mask process)

Next, as shown in FIG. 3B, a gate insulating film 207 is formed on the substrate having the common wiring 205. In this case, the gate insulating film 207 may be a silicon oxide film or a silicon nitride film. Thereafter, an amorphous silicon layer, a silicon layer doped with impurities, and a second metal layer are sequentially formed on the gate insulating layer 207. The second metal film is for forming a data line, and may be made of the same material as the first metal film.

Next, the second metal layer, the silicon layer doped with an impurity, and the amorphous silicon layer are patterned to form a matrix structure with the semiconductor layer 207 including the active layer 207a and the ohmic contact layer 207b and the gate wiring. The wiring 209 is formed. In this case, the data line 209 includes a source electrode 209S, a drain electrode 209D, a storage electrode 209S, and a data pad 209P of the thin film transistor. Meanwhile, the active layer 209a between the source electrode 209S and the drain electrode 209D corresponds to the channel region of the thin film transistor. In this case, the semiconductor layer 207 and the data line 209 may be formed by a photolithography process using a resist pattern. (2nd photo mask process)

Next, as shown in FIG. 3C, a protective film 213 is formed on the substrate having the data line 209. At this time, the protective film 213 is a photo acrylic film is used. In this case, when the photoacrylic film is applied as the passivation layer 213, the parasitic voltage between the data line and the pixel electrode may be reduced to realize high brightness through a high aperture ratio and may reduce power consumption. However, when the protective film 213, which is a photoacrylic film, is in direct contact with the channel region of the thin film transistor, the device characteristics are degraded. Therefore, in order to protect the channel region of the thin film transistor, a silicon nitride film 211 that is a channel protective film is formed under the protective film 213. Here, the photo acrylic film is formed by spin coating because it is impossible to deposit the film in the chemical vapor deposition chamber due to film characteristics such as peeling. In addition, the photoacryl film is formed by sputtering, and then soft-baked at 90 ° C.

Subsequently, a transparent conductive film is formed on the protective film 213. In this case, the transparent conductive film may be indium tin oxide (ITO). Thereafter, the transparent conductive film is selectively wet-etched to form a transparent conductive film pattern 215 exposing portions corresponding to the gate pad 203P, the data pad 209P, and the storage electrode 205C. In this case, the wet etching process of the transparent conductive film may be selectively performed using a separate photoresist pattern. Then, the protective film 213 exposed by the transparent conductive film pattern 215 is developed and removed. Subsequently, the silicon nitride film 211 exposed by the remaining protective film 213 is removed by dry etching. As a result, the first, second, and respective exposures of the gate pad 203P, the data pad 209P, and the storage electrode 205C to the transparent conductive film pattern 215, the protective film 213, and the silicon nitride film 211 are exposed. Third openings 216H1, 216H2, and 216H3 are formed. That is, the first, second and third openings 216H1, 216H2, and 216H3 may be formed by a photo process using a resist pattern.

As described above, when the photo process is performed, the transparent conductive film has a light transmittance of 90% or more, so that the photoacryl film may be developed by adjusting the exposure amount and the exposure intensity. After developing the photo acrylic film, the developed photo acrylic film is accompanied by a separate hard bake process.

Subsequently, as shown in FIG. 3D, a conductive film is formed on the substrate having the first, second and third openings 216H1, 216H2, and 216H3. The conductive film may be formed using at least one of Ti, Mo, and Mo-Ti alloys. Subsequently, the conductive layer is patterned to form conductive layer patterns 217P1 and 217P2 and the pixel electrode 217. In this case, the conductive layer patterns 217P1 and 217P2 are patterned to cover the gate pad 203P and the data pad 209P, respectively.

In addition, as illustrated in FIG. 2, the pixel electrode 217 includes a plurality of vertical portions 217a and a horizontal portion 217b connecting the vertical portions 217a to one. The horizontal portion 217b of the pixel electrode 217 is formed to be connected to the storage electrode 209D through the third opening 216H3, and the vertical portion 217b of the pixel electrode 217 is the common electrode. It is formed alternately with 205C.

The conductive layer patterns 217P1, 217P2 and the pixel electrode 217 may be formed by a photolithography process using a resist pattern.

In the liquid crystal display device according to the present invention formed by the above process, as shown in FIGS. 2 and 3D, the gate pad 203P and the gate electrode 203G are formed on the substrate 201 in which a plurality of pixel regions are defined. The gate wiring 203 is provided and the common wiring 205 is spaced apart from the gate wiring 203 at predetermined intervals and provided with the common electrode 205C. In this case, the gate wiring 203 and the common wiring 205 are patterned with the same film. In detail, the gate wiring 203 and the common wiring 205 may be formed of at least one of Al, Cu, Ta, Ti, Mo, Mo alloys, and Al alloys.

A gate insulating film 205 is formed on the substrate having the common wiring 205.

The data line 209 and the common line 205 formed on the gate insulating layer 205 to cross the gate line 203 and provided with a data pad 209P and a source electrode / drain electrode 209S and 209D. Are formed to overlap each of the storage electrodes 209S. In this case, the data line 209 and the storage electrode 209S are formed of the same film. In detail, the data line 209 and the storage electrode 209S may be formed of at least one of Al, Cu, Ta, Ti, Mo, Mo alloys, and Al alloys.

Further, a protective film 213 made of a photo acrylic film exposing the gate pad 203P, the data pad 209P and the storage electrode 209S is formed on the substrate having the storage electrode 209S. In this case, a channel passivation layer 211 is interposed between the gate insulating layer 205 and the passivation layer 213. As the channel protective film 211, a silicon nitride film is used.

The conductive layer patterns 217P1 and 217P2 connected to the gate pad 203P and the data pad 2109P and the pixel electrode 217 connected to the storage electrode 209S are formed on the passivation layer 213. Each is arranged. In addition, a transparent conductive layer pattern 215 is interposed between the passivation layer 213 and the pixel electrode 217. In this case, the conductive layer patterns 217P1 and 217P2 and the pixel electrode 217 are formed of the same layer. In detail, the conductive layer patterns 217P1 and 217P2 and the pixel electrode 217 may be formed using at least one of Ti, Mo, and Mo-Ti alloys.

In the fabrication of an array substrate of a transverse electric field type liquid crystal display device according to the present invention, four masks (gate wiring formation, data wiring formation, protective film opening formation, and pixel electrode formation) are used. Therefore, in the present invention, the protective film opening forming process, which has been performed by the conventional two-time photo mask process, can be reduced by one time.

That is, in the present invention, a transparent conductive film is formed on the passivation film, which is a photo acrylic film, instead of the conventional silicon nitride film, and an opening is formed by developing and removing the photo acrylic film by appropriately utilizing the light transmitting property of the transparent conductive film. Therefore, in the process of forming an opening in the protective film, the present invention can simplify the process by reducing the existing two-time photo mask process once.

According to the present invention, a transparent conductive film is formed on the protective film made of the photo acrylic film, and the opening is formed by exposing and developing the protective film by using the transparent property of the transparent conductive film. Therefore, there is an advantage of simplifying the process by reducing the protective film opening portion forming process, which has been performed in the conventional two-time photo mask process, by one time.

Claims (22)

A substrate in which a plurality of pixel regions are defined; A gate wiring formed on the substrate, spaced apart from the gate wiring at a predetermined interval, and provided with a gate pad and a gate electrode; A gate insulating film formed on the substrate having the common wiring; A data wiring formed on the gate insulating film to intersect the gate wiring and including a data pad and a source electrode and a drain electrode; The storage electrode formed on the gate insulating layer to overlap the common wiring; A protective film formed on a substrate having the storage electrode and comprising a photo acrylic film exposing the gate pad, the data pad, and the storage electrode; A pixel electrode formed on the passivation layer, the transparent conductive film patterns connected to the gate pad and the data pad, and the pixel electrode connected to the storage electrode; And a transparent conductive film pattern interposed between the protective film and the pixel electrode. The liquid crystal display device of claim 1, wherein the gate line and the common line are patterned on the same layer. The liquid crystal display device according to claim 2, wherein the gate wiring and the common wiring are formed of at least one of Al, Cu, Ta, Ti, Mo, Mo alloy, and Al alloy. The liquid crystal display device of claim 1, wherein the data line and the storage electrode are formed of the same layer. The liquid crystal display device of claim 4, wherein the data line and the storage electrode are formed of at least one of Al, Cu, Ta, Ti, Mo, Mo alloys, and Al alloys. The liquid crystal display device of claim 1, further comprising a channel passivation layer interposed between the gate insulating layer and the passivation layer. 7. The liquid crystal display device according to claim 6, wherein the channel protective film is a silicon nitride film. The liquid crystal display device of claim 1, further comprising a transparent conductive layer pattern interposed between the pixel electrode including the conductive layer patterns and the passivation layer. The liquid crystal display device of claim 1, wherein the conductive layer patterns and the pixel electrode are formed of at least one of Ti, Mo, and Mo-Ti alloys. Forming a gate wiring with a gate electrode, a gate pad, and a common wiring with a common electrode on the substrate; Forming a gate insulating film on the substrate having the common wiring; Forming a data electrode crossing the gate line and a storage electrode overlapping the common line, wherein the data line comprises a source electrode, a drain electrode, and a data pad; Sequentially forming a protective film made of a photo acrylic film and a transparent conductive film on the substrate having the data wirings; Patterning the transparent conductive layer and the passivation layer to form respective first, second, and third openings exposing the gate pad, the data pad, and the storage electrode; Forming a conductive film on the substrate having the first, second and third openings; Patterning the conductive layer and the remaining transparent conductive layer to form conductive layer patterns connected to the gate pad and the data pad and a pixel electrode connected to the storage electrode. The method of claim 10, wherein the gate wiring and the common wiring are formed of the same film. The method of claim 11, wherein the gate wiring and the common wiring are formed of at least one of Al, Cu, Ta, Ti, Mo, Mo alloy, and Al alloy. 12. The method of claim 11, wherein the data line and the storage electrode are formed in the same layer. The method of claim 13, wherein the data line and the storage electrode are formed of at least one of Al, Cu, Ta, Ti, Mo, Mo alloys, and Al alloys. The method of claim 10, further comprising forming a channel passivation layer between the gate insulating layer and the passivation layer. 16. The method of claim 15, wherein the channel protective film is formed of a silicon nitride film. The method of claim 10, wherein the passivation layer is formed by a spin coating process. The method of claim 10, wherein before forming the transparent conductive film, Soft-baking the protective film manufacturing method of a liquid crystal display device. 19. The method of claim 18, wherein the first, second and third openings are formed Selectively exposing and developing the transparent conductive film and the protective film on which the soft baking is completed; And hard-baking the protective film on which the development is completed. The method of claim 10, wherein the transparent conductive film is formed of an ITO film. The method of claim 10, wherein the conductive layer patterns and the pixel electrode are formed of the same layer. The method of claim 21, wherein the conductive layer patterns and the pixel electrode are formed of at least one of Ti, Mo, and Mo-Ti alloys.

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