KR101411792B1 - Fabricating Method Of Transflective Type LCD - Google Patents

Abstract

The present invention relates to a method of manufacturing a transflective liquid crystal display device capable of shortening the processing time by reducing the number of processes for forming an embossing pattern.

A method of manufacturing a transflective liquid crystal display device includes the steps of: forming a gate line; Forming a data line that is formed in an intersection with the gate line and defines a pixel region having a transmissive region and a reflective region; Forming a thin film transistor connected to the gate line and the data line; Forming a pixel electrode which is connected to the drain electrode of the thin film transistor and which receives a signal from the data line; Exposing the pixel electrode through a through hole corresponding to the transmissive region and forming an organic film pattern having an embossed surface corresponding to the reflective region; Forming a reflective electrode on the organic film pattern having the surface of the embossed shape; The organic film pattern is formed through a single photolithography process using one mask.

Embossing, semi-permeable, mask

Description

Technical Field [0001] The present invention relates to a fabrication method of a transflective liquid crystal display device,

The present invention relates to a method of manufacturing a transflective liquid crystal display device, and more particularly, to a method of manufacturing a transflective liquid crystal display device capable of shortening the processing time by reducing the number of processes for forming an embossing pattern.

2. Description of the Related Art In general, a liquid crystal display (LCD) displays an image by allowing each of liquid crystal cells arranged in a matrix form to control light transmittance according to a video signal.

2. Description of the Related Art In general, a liquid crystal display (LCD) displays an image by allowing each of liquid crystal cells arranged in a matrix form to control light transmittance according to a video signal.

As shown in FIG. 1, the liquid crystal display includes a thin film transistor array substrate 20 and a color filter array substrate 10 which are bonded together facing each other with a liquid crystal 16 interposed therebetween.

The color filter array substrate 10 includes a black matrix 13 for preventing light leakage which is laminated on the upper glass substrate 11, a color filter 12 for color implementation, a common electrode An electrode 14, and an upper alignment film applied thereon for liquid crystal alignment.

The thin film transistor array substrate 20 includes a gate line 23 and a data line 24 which are formed on the lower glass substrate 21 so as to intersect with each other and thin film transistors 26 A pixel electrode 25 connected to the thin film transistor 26, and a lower orientation film applied thereon for liquid crystal alignment.

Such a liquid crystal display device is categorized into a transmission type in which an image is displayed using light incident from a back light unit and a reflection type in which an external light such as natural light is reflected to display an image. In the transmissive type, the power consumption of the backlight unit is large, and since the reflective type relies on external light, there is a problem that an image can not be displayed in a dark environment.

In order to solve the above problems, a transflective liquid crystal display device has been proposed in which a transmissive mode using a backlight unit and a reflective mode using external light can be selected. Since the semi-transmissive liquid crystal display device operates in a reflective mode when the external light is sufficient and in a transmissive mode using the backlight unit if the external light is insufficient, the power consumption can be reduced as compared with the transmissive type.

A transflective liquid crystal display device has a reflective electrode formed on a thin film transistor array substrate for reflecting external light incident through a color filter substrate toward a color filter array substrate. The reflective electrode has an embossed shape along an organic film formed to have an embossed surface below the reflective electrode, thereby enhancing the reflection efficiency through the scattering effect. Therefore, the region where the reflective electrode is formed becomes the reflective region of each pixel region, and the region where the reflective electrode is not formed becomes the transmissive region of each pixel region.

However, in such a conventional transflective liquid crystal display device, two photolithography processes must be performed using two masks in forming an organic film of an embossing pattern on a thin film transistor array substrate. In other words, in order to form an organic film of an embossed pattern on a conventional thin film transistor array substrate, a first mask 30 is placed on a thin film transistor array substrate on which a photosensitive organic film 50 is formed as shown in FIG. 2A, 2B, the second mask 40 is positioned on a thin film transistor array substrate having an embossed pattern formed thereon, and then irradiated with ultraviolet (UV) light to form an embossed pattern, A second photolithography step is required to remove the residual organic film on the substrate. The first and second masks 30 and 40 are provided with transmissive layers 32 and 42 through which ultraviolet rays are transmitted and barrier layers 34 and 44 through which ultraviolet rays can not be transmitted. Has a positive property in which a portion exposed to ultraviolet rays is removed. Meanwhile, the exposure process belonging to a part of the photolithography process includes a stepper method in which the exposure equipment stops for a predetermined period of time on the area to be exposed, and exposure is performed while continuously moving the exposure equipment on the area to be exposed Is known. The scanning method is advantageous for shortening the processing time as compared with the stepper method.

As described above, the conventional transflective liquid crystal display device has to be subjected to two photolithography processes in order to form an organic film of an embossing pattern.

In particular, since the conventional transflective liquid crystal display device must undergo two photolithography processes using different masks to form an organic film of an embossing pattern, it is impossible to expand into a scan exposure method.

Accordingly, it is an object of the present invention to provide a method of manufacturing a transflective liquid crystal display device capable of shortening the processing time by reducing the number of processes for forming an embossing pattern.

According to an aspect of the present invention, there is provided a method of manufacturing a transflective liquid crystal display device, including: forming a gate line; Forming a data line that is formed in an intersection with the gate line and defines a pixel region having a transmissive region and a reflective region; Forming a thin film transistor connected to the gate line and the data line; Forming a pixel electrode which is connected to the drain electrode of the thin film transistor and which receives a signal from the data line; Exposing the pixel electrode through a through hole corresponding to the transmissive region and forming an organic film pattern having an embossed surface corresponding to the reflective region; Forming a reflective electrode on the organic film pattern having the surface of the embossed shape; The organic film pattern is formed through a single photolithography process using one mask.

The organic film pattern includes a negative type photosensitive organic material in which a portion exposed to ultraviolet rays is not removed while the portion not exposed to ultraviolet rays is removed during the photolithography process.

The forming of the organic film pattern may include: applying the photosensitive organic material on the thin film transistor and the pixel electrode; A transmissive layer positioned in a region where the convex portion of the embossed organic film pattern is to be formed to transmit the ultraviolet rays; a partially transparent layer positioned in a region where the concave portion of the embossed organic film pattern is to be formed, Aligning a mask on the photosensitive organic material, the mask having a barrier layer positioned in a region where the through hole is to be formed and blocking transmission of the ultraviolet light; And irradiating the mask with ultraviolet rays in a scanning method or a stepper method.

The mask is a halftone mask.

In the method of manufacturing a transflective liquid crystal display device according to the present invention, a process of forming an embossed pattern of an organic film is realized by a single photolithographic process using a photosensitive material having a halftone mask and a negative property. Accordingly, the manufacturing method of a transflective liquid crystal display device according to the present invention can reduce the number of processes for forming an embossing pattern, thereby shortening the processing time. Further, among the methods for exposure, the exposure equipment does not stop on the area to be exposed It is also possible to expand the scanning method in which exposure is performed while moving continuously.

Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS. 3 to 5E.

3 is a plan view of a liquid crystal display panel of a transflective liquid crystal display device according to an embodiment of the present invention. 4 is a cross-sectional view taken along line I-I 'of FIG.

3 and 4, a liquid crystal display panel of a transflective type liquid crystal display according to an embodiment of the present invention includes a color filter array substrate 200 and a thin film transistor array substrate 100 which are opposed to each other, A spacer for keeping the cell gap constant between the substrates 100 and 200, and a liquid crystal filled in the space provided by the spacers.

The color filter array substrate 200 is composed of a black matrix for preventing light leakage, a color filter for color implementation, a common electrode that forms a vertical electric field with the pixel electrode, and an upper alignment layer coated thereon for liquid crystal alignment.

The thin film transistor substrate 100 includes a gate line 102 and a data line 104 which are formed so as to intersect with each other and define respective pixel regions, a thin film transistor (TFT) connected to the gate line 102 and the data line 104, A pixel electrode 122 formed in the pixel region and connected to the thin film transistor TFT, a reflective electrode 130 formed in the reflective region of the pixel region, and a lower alignment layer applied thereon for liquid crystal alignment.

The gate line 102 is connected to a gate driver (not shown) through a gate pad 170. [ The gate pad 170 includes a gate pad lower electrode 172 extended from the gate line 102 and a gate pad upper portion 172 formed in the first contact hole 176 penetrating the gate insulating film 112 and the protective film 118. [ And an electrode 174.

The data line 104 is connected to a data driver (not shown) through a data pad 180. The data pad 180 is composed of a data pad lower electrode 182 extended from the data line 104 and a data pad upper electrode 184 formed in the second contact hole 186 passing through the protective film 118 .

The thin film transistor TFT selectively supplies a data signal from the data line 104 to the pixel electrode 122 in response to a gate signal from the gate line 102. The thin film transistor TFT includes a gate electrode 106 connected to the gate line 102, a source electrode 108 connected to the data line 104, a drain electrode 110 connected to the pixel electrode 122, An active layer 114 which overlaps the gate electrode 106 and the gate insulating layer 112 and forms a channel between the source electrode 108 and the drain electrode 110 while the active layer 114 and the source electrode 108 overlap each other, And an ohmic contact layer 116 for ohmic contact with the drain electrode 110.

The pixel electrode 122 is formed in a pixel hole 134 passing through the protective film 118 and the gate insulating film 112 in the pixel region provided at the intersection of the data line 104 and the gate line 102, (Not shown). The pixel electrode 122 generates a potential difference with a common electrode (not shown) by a data signal supplied through the thin film transistor (TFT). The potential difference causes the liquid crystal to rotate, and the amount of light transmission is determined according to the degree of rotation of the liquid crystal in each of the reflective region and the transmissive region.

The reflective electrode 130 reflects external light incident through the color filter array substrate 200 toward the color filter array substrate 200. The reflective electrode 130 has an embossed shape along the organic film 120 formed to have an embossed surface below the reflective electrode 130, thereby enhancing reflection efficiency by a scattering effect. The region where the reflective electrode 130 is formed is a reflective region of each pixel region, and the region where the reflective electrode 130 is not formed is a transmissive region of each pixel region. The organic film 120 includes a negative type photosensitive material from which a portion not exposed to ultraviolet rays is removed. The organic layer 120 has an embossed surface through a single exposure process using a halftone mask including a transmissive layer, a partially transmissive layer, and a barrier layer. This will be described later in detail with reference to FIG. 5D.

A transmission hole 132 passing through the organic film 120 is formed in the transmission region so that the length of the optical path passing through the liquid crystal layer in the reflection region and the transmission region is the same. As a result, the reflected light RL incident on the reflective region is reflected by the reflective electrode 130 via the liquid crystal layer, and is emitted to the outside via the liquid crystal layer. Then, the transmitted light TL of the backlight unit 136 incident on the transmissive region passes through the liquid crystal layer and is emitted to the outside. Accordingly, since the lengths of the optical paths in the reflection area and the transmission area are the same, the transmission efficiency of the reflection mode and the transmission mode of the liquid crystal display device are the same. The liquid crystal may be formed by a dropping method in which a liquid crystal is dropped onto at least one substrate in addition to a vacuum injection method to form a liquid crystal layer.

The thin film transistor array substrate 100 according to the present invention further includes a storage capacitor Cst in order to stably maintain the video signal charged in the pixel electrode 122. The storage capacitor Cst includes a storage line 128 and a storage electrode 124 which are overlapped with each other with a gate insulating film 112, an active layer 114, and an ohmic contact layer 116 interposed therebetween. The storage line 128 is formed to cross the pixel region in a direction parallel to the gate line 102. The storage electrode 124 is exposed through the pixel hole 134 and laterally connected to the pixel electrode 122. [

5A to 5E are cross-sectional views showing a method of manufacturing the transflective thin film transistor array substrate shown in FIG.

5A, a first group of conductive patterns including a gate line 102, a gate electrode 106, a gate pad lower electrode 172, and a storage line 128 is formed on a lower glass substrate 101 .

A gate metal layer is formed on the lower glass substrate 101 through a deposition method such as sputtering. The gate metal layer is patterned by a photolithography process and an etching process to form a first conductive pattern group including the gate line 102, the gate electrode 106 and the gate pad lower electrode 172 and the storage line 128. As the gate metal layer, a single layer or multilayer structure of Al, Mo, Cr, Cu, Al alloy, Mo alloy, Cu alloy, or the like is used.

5B, a semiconductor pattern including a gate insulating layer 112 formed on a lower glass substrate 101 on which a first group of conductive patterns is formed, an active layer 114 and an ohmic contact layer 116 formed on the gate insulating layer 112; A second conductive pattern group including the data line 104, the source electrode 108, the drain electrode 110, and the storage electrode 124 is formed.

A gate insulating layer 112, an amorphous silicon layer, an amorphous silicon layer doped with impurities, and a source / drain metal layer are successively formed on a lower glass substrate 101 on which a first group of conductive patterns is formed through a deposition method such as PECVD or sputtering . An inorganic insulating material such as silicon oxide (SiO x) or silicon nitride (SiN x) is used as the gate insulating film 112 and an inorganic insulating material such as Al, Mo, Cr, Cu, Al alloy, Mo alloy, Single layer or double layer structures are used.

A photoresist pattern is formed on the source / drain metal layer so that the channel portion has a lower height than the other source / drain pattern portions. The source / drain metal layer is patterned by the wet etching process using the photoresist pattern to form the data line 104, the source electrode 108, the drain electrode 110 integrated with the source electrode 108, and the storage electrode 124 A second conductive pattern group including the second conductive pattern group is formed.

Then, the amorphous silicon layer and the amorphous silicon layer doped with the impurity are simultaneously patterned by the dry etching process using the same photoresist pattern, thereby forming the ohmic contact layer 116 and the active layer 114.

After the photoresist pattern having a relatively low height is removed in the ashing process, the source / drain pattern of the channel portion and the ohmic contact layer 116 are etched by the dry etching process. Thus, the active layer 114 of the channel portion is exposed, and the source electrode 108 and the drain electrode 110 are separated.

Then, the photoresist pattern remaining on the second conductive pattern group is removed in the strip process.

Referring to FIG. 5C, the lower insulating substrate 101 on which the second conductive pattern group is formed is provided with a gate insulating layer 112, a pixel hole 134 passing through the passivation layer 118, first and second contact holes 176 and 186, A pixel electrode 122, a gate pad upper electrode 174, and a data pad upper electrode (not shown) formed in the pixel hole 134, the first and second contact holes 176 and 186, 184 are formed.

A protective film 118 is formed on the lower glass substrate 101 on which the second conductive pattern group is formed. As the protective film 118, an inorganic insulating material such as the gate insulating film 112 is used. A photoresist pattern for patterning the protective film 118 and the gate insulating film 112 is formed on the protective film 118 by a photolithography process. In the etching process using the photoresist pattern as a mask, a hole 134 and first and second contact holes 176 and 186 penetrating the protective film 118 and the gate insulating film 112 are formed. Then, a transparent conductive film is formed on the entire surface so as to cover the photoresist pattern. As the transparent conductive film, indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (TO), indium tin zinc oxide (ITZO) . Then, the third conductive pattern group including the pixel electrode 122, the gate pad upper electrode 174, and the data pad upper electrode 184 is formed by removing the photoresist pattern by a lift-off process. The protective layer 118 may not be formed.

5D, an organic layer 120 having a through-hole 132 corresponding to a transmissive region and having a surface of an embossed shape corresponding to a reflective region is formed on a lower glass substrate 101 on which a third group of conductive patterns is formed, A pattern is formed.

The organic film 120 is entirely coated on the lower glass substrate 101 on which the third conductive pattern group is formed. As the organic film 120, a negative type photosensitive organic material such as acrylic is used. The negative photosensitive organic material has a property that portions exposed to ultraviolet light remain unremoved while portions unexposed to ultraviolet light are removed.

Then, the halftone mask 190 is aligned on the organic film 120. The halftone mask 190 has a transparent quartz (SiO2) substrate 192 and a transmissive layer H, a partially transmissive layer T and a barrier layer B formed thereon. Here, the transmissive layer H is located in a region where the convex portion of the embossed pattern is to be formed, and ultraviolet light (UV) is transmitted, so that the organic material remains after the development. The partially transparent layer (T) is located in a region where the concave portion of the embossed pattern is to be formed, and partially transmits ultraviolet rays (UV), thereby leaving a thinner organic material than the organic material forming the convex portion after development. The barrier layer (B) is located in a region where the through holes (132) are to be formed, thereby blocking the transmission of ultraviolet (UV) light, thereby removing the organic material after development. For this purpose, the barrier layer (B) is formed of a metal such as Cr, CrOx and the like, and the partially transparent layer (T) is formed of MoSix or the like.

Accordingly, the organic layer 120 corresponding to the transmissive region is removed, and the transmissive hole 132 is formed. The organic film 120 corresponding to the reflection region has a surface having an embossed shape regularly different in thickness. The transmission hole 132 and the embossing pattern forming process can be realized by a single photolithographic process with the halftone mask 190 and the photosensitive organic film 120 having a negative property. Therefore, in the method of manufacturing a transflective liquid crystal display device according to an embodiment of the present invention, not only a stepper method in which the exposure equipment stops for a certain period of time on the area to be exposed, but also the exposure equipment does not stop on the area to be exposed It can be applied to a scanning method in which exposure is continuously performed while moving continuously.

Referring to FIG. 5E, a reflective electrode 130 is formed on an organic film 120 having an embossed shape.

A reflective metal layer is laminated on the organic film 120 having an embossing surface while maintaining an embossed shape. As the reflective metal layer, a metal having a high reflectance such as Al, AlNd, or the like is used.

Then, the reflective metal layer is patterned by a photolithography process and an etching process, thereby forming the reflective electrode 130.

As described above, in the method of manufacturing a transflective liquid crystal display device according to the present invention, the embossing pattern forming process of the organic film is realized by a single photolithography process using a halftone mask and a photosensitive material having negative properties. Accordingly, the manufacturing method of a transflective liquid crystal display device according to the present invention can reduce the number of processes for forming an embossing pattern, thereby shortening the processing time. Further, among the methods for exposure, the exposure equipment does not stop on the area to be exposed It is also possible to expand the scanning method in which exposure is performed while moving continuously.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

1 is a perspective view showing a conventional liquid crystal display panel.

FIGS. 2A and 2B are process cross-sectional views illustrating the formation of an organic film of an embossed pattern in a conventional transflective liquid crystal display device.

3 is a plan view of a liquid crystal display panel of a transflective liquid crystal display device according to an embodiment of the present invention.

Fig. 4 is a cross-sectional view taken along line I-I 'of Fig. 3; Fig.

FIGS. 5A to 5E are process sectional views illustrating a method of manufacturing the liquid crystal display panel shown in FIG. 4;

Description of the Related Art

100: thin film transistor array substrate 101: lower glass substrate

102: gate line 104: data line

106: gate electrode 108: source electrode

110: drain electrode 112: gate insulating film

114: active layer 116: ohmic contact layer

118: protective film 120: organic film

122: pixel electrode 124: storage electrode

128: storage line 130: reflective electrode

132: Through hole 134:

170: gate pad 172: gate pad lower electrode

174: gate pad upper electrode 176: first contact hole

180: Data pad 182: Data pad lower electrode

184: Data pad upper electrode 186: Second contact hole

190: Halftone mask 192: Transparent quartz substrate

200: Color filter array substrate

Claims (4)

Forming a gate line; Forming a data line that is formed in an intersection with the gate line and defines a pixel region having a transmissive region and a reflective region; Forming a thin film transistor connected to the gate line and the data line; Forming a pixel electrode which is connected to the drain electrode of the thin film transistor and which receives a signal from the data line; Exposing the pixel electrode through a through hole corresponding to the transmissive region and forming an organic film pattern having an embossed surface corresponding to the reflective region; Forming a reflective electrode on the organic film pattern having the surface of the embossed shape; Wherein the organic film pattern is formed through a single photolithography process using one mask. ≪ RTI ID = 0.0 > 18. < / RTI > The method according to claim 1, Wherein the organic film pattern includes a negative photosensitive organic material in which a portion exposed to ultraviolet light is not removed while a portion not exposed to ultraviolet light is removed during the photolithography process, Manufacturing method. 3. The method of claim 2, The forming of the organic film pattern may include: Applying the photosensitive organic material on the thin film transistor and the pixel electrode; A transmissive layer positioned in a region where the convex portion of the embossed organic film pattern is to be formed to transmit the ultraviolet rays; a partially transparent layer positioned in a region where the concave portion of the embossed organic film pattern is to be formed, Aligning a mask on the photosensitive organic material, the mask having a barrier layer positioned in a region where the through hole is to be formed and blocking transmission of the ultraviolet light; And irradiating ultraviolet light onto the mask in a scanning or stepper manner. The method of claim 3, Wherein the mask is a halftone mask. ≪ RTI ID = 0.0 > 21. < / RTI >

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