KR20080061540A - Method for fabricating transflective type liquid crystal display device - Google Patents

Abstract

A method for manufacturing a transflective LCD device is provided to reduce a usage frequency of an exposure mask by using a shadow mask in a process of forming a reflection electrode and an uneven pattern. A sub pixel divided into a reflection unit(R) and a transmission unit(T) is defined by vertically crossing a gate line with a data line(115) on a substrate(111). A TFT(Thin Film Transistor) is formed in an intersection of the two lines. A transmitting electrode(117) contacted with a drain electrode(115b) of the TFT is formed in a predetermined area of the transmission unit. A first shadow mask having an opening is disposed in the reflection unit. An organic insulating layer(160) having a rough surface is formed by non-uniformly applying organic insulating material. A reflection electrode(124) contacted with the transmitting electrode is formed on the organic insulating layer.

Description

Method for manufacturing transflective liquid crystal display device {Method For Fabricating Transflective Type Liquid Crystal Display Device}

1 is a cross-sectional view of a transflective liquid crystal display device according to the prior art.

2 is a cross-sectional view of a transflective liquid crystal display device according to the present invention;

3A, 4A, 5A, 6A, 7A, and 8A are process plan views of a transflective liquid crystal display device according to the present invention;

3B, 4B, 5B, 6B, 7B, and 8B are process cross-sectional views of the transflective liquid crystal display device according to the present invention;

9 and 10 are plan views of shadow masks according to the present invention;

* Explanation of symbols on the main parts of the drawings

111: TFT array substrate 112: gate wiring

113: gate insulating film 115: data wiring

116: protective film 117: transmission electrode

118: contact hole 119: contact hole

122: gate pad 124: reflective electrode

125: data pad 160: organic insulating film

162, 165: first and second antioxidant film

501 and 503: first and second shadow masks

502, 504: frame

The present invention relates to a liquid crystal display device, and more particularly, to a method of manufacturing a transflective liquid crystal display device which is intended to reduce process time and cost by reducing the number of times of use of an exposure mask.

Recently, the liquid crystal display device, one of the flat panel display devices that are attracting attention, is an element that changes the optical anisotropy by applying an electric field to a liquid crystal that combines the liquidity and the optical properties of the crystal, which is applied to a conventional cathode ray tube. Compared with its low power consumption, small volume, large size, and high definition, it is widely used.

The liquid crystal display may be classified into two types, a transmissive liquid crystal display device using a backlight as a light source and a reflective liquid crystal display device using external natural light without using the backlight as a light source. Although it is possible to realize a bright image, the power consumption is large, and the reflection type liquid crystal display device does not use a backlight, so power consumption is reduced. However, when the external natural light is dark, there is a limitation that it is impossible to use.

Therefore, it is common to use a large number of reflective liquid crystal display elements in electronic devices such as clocks and calculators, and a large number of transmissive liquid crystal display elements in notebook computers requiring high quality image display.

Recently, researches on semi-transmissive liquid crystal display devices that compensate for the disadvantages of the reflective liquid crystal display device and the transmissive liquid crystal display device have been actively conducted. It is possible to use both ways.

That is, when the external natural light is bright enough to enable the display function without using the backlight, the external light incident through the upper substrate is reflected by the reflective electrode to operate as a reflective liquid crystal display device, and when the external light is not bright, the backlight is used. The light of the backlight enters the liquid crystal layer through the transmissive electrode to operate as a transmissive liquid crystal display device.

Hereinafter, a translucent liquid crystal display device according to the prior art will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a transflective liquid crystal display device according to the prior art.

A semi-transmissive liquid crystal display device in which one sub-pixel is divided into a reflecting portion R and a transmitting portion T includes a thin film transistor array substrate having a plurality of wirings and a thin film transistor, and a thin film transistor array substrate facing the thin film transistor array substrate. And a liquid crystal layer encapsulated between the color filter layer array substrate and the thin film transistor array substrate and the color filter layer array substrate. In this case, a backlight assembly (not shown) for supplying light is further provided below the transflective liquid crystal display.

In this case, as shown in FIG. 1, the thin film transistor array substrate 11 includes a gate wiring (not shown) and a data wiring 15 defining a sub-pixel by perpendicularly crossing each other, and the gate wiring and A thin film transistor TFT formed at the intersection of the data lines, a transmissive electrode 17 formed in the transmissive portion T of the sub-pixel, and a reflective electrode formed in the reflective portion R of the sub-pixel, 24).

A gate insulating film 13 is further provided between the layer on which the gate wiring is provided and the layer on which the data wiring 15 is provided, and the layer on which the data wiring 15 is provided and the transmissive electrode 17 are formed. A protective film 16 is further provided between the layers to insulate the two layers from each other.

The transmissive electrode 17 extends to not only the transmissive portion T but also the reflecting portion R, and the reflecting electrode 24 is limited to the reflecting portion R. The transmissive electrode 17 and the reflecting electrode ( 24 are contacted with each other to apply the same voltage. The transmissive electrode 17 and the reflective electrode 24 are commonly applied with a pixel voltage. For this purpose, the transmissive electrode 17 and the reflective electrode 24 are connected to the drain electrode 15b of the thin film transistor.

On the other hand, the reflective electrode 24 is formed on the surface of the unevenness, which is formed by the organic insulating film 60 is formed under the reflective electrode and having the uneven pattern on the surface.

The transflective liquid crystal display device according to the prior art as described above has the following problems.

That is, in order to form the gate wiring layer, the semiconductor layer, the data wiring layer, the contact hole of the protective film, the concave-convex pattern, the transmissive electrode and the reflective electrode in the TFT array substrate of the transflective liquid crystal display device according to the prior art, at least seven exposure masks are In this case, as the number of times of use of the photomask is increased, the process is complicated and the process time and the process cost are high, so the process efficiency is greatly reduced.

Recently, researches for reducing the number of times of use of the exposure mask have been actively conducted. For example, a patterning process is performed using a diffraction exposure mask to collectively pattern the semiconductor layer and the data wiring layer.

However, even if the semiconductor layer and the data wiring layer are patterned by using the diffraction exposure mask, at least six exposure masks are required to complete the TFT array substrate of the transflective liquid crystal display device. There is a situation.

Accordingly, the present invention has been made to solve the above problems, the method of manufacturing a transflective liquid crystal display device to reduce the number of times of use of the exposure mask by using a shadow mask in the process of forming the reflective electrode and uneven pattern. The purpose is to provide.

The method of manufacturing a transflective liquid crystal display device of the present invention for achieving the above object is to form a vertical intersection of the gate wiring and data wiring on the substrate to define a sub-pixel divided into a reflecting portion and a transmitting portion, and the intersection of the two wirings Forming a thin film transistor at a point; forming a transmissive electrode in contact with a drain electrode of the thin film transistor in a predetermined region; and placing a first shadow mask having an opening in the reflecting portion, and forming an organic insulating material. And forming an organic insulating film having a rough surface by unevenly applying the same, and forming a reflective electrode contacting the transmissive electrode on the organic insulating film.

According to another aspect of the present invention, there is provided a method of manufacturing a transflective liquid crystal display device, which defines a sub-pixel divided into a reflective part and a transmissive part by vertically forming a gate line and a data line on a substrate, and at the intersection of the two lines. Forming a thin film transistor, forming a transmissive electrode in contact with a drain electrode of the thin film transistor in a predetermined region of the thin film transistor, forming an organic insulating film having an uneven pattern on the reflecting portion, and forming the organic insulating film Arranging a shadow mask on the substrate and depositing a reflective material to form a reflective electrode in contact with the transmissive electrode.

Hereinafter, a method of manufacturing a transflective liquid crystal display device according to the present invention having the above characteristics will be described in detail with reference to the accompanying drawings.

2 is a cross-sectional view of a transflective liquid crystal display device according to the present invention, and FIGS. 3A, 4A, 5A, 6A, 7A and 8A are process plan views of the transflective liquid crystal display device according to the present invention, and FIGS. 3B, 4B, 5B, 6b, 7b and 8b are process cross-sectional views of the transflective liquid crystal display device according to the present invention.

As shown in FIG. 2, the thin film transistor array substrate 111 of the transflective liquid crystal display device according to the present invention has a gate wiring defining a sub-pixel divided into a reflection part R and a transmission part T by vertical crossing. (Not shown) and the data wiring 115, the gate insulating film 113 formed on the front surface between the gate wiring and the data wiring, the thin film transistor TFT formed at the intersection of the gate wiring and the data wiring; And a passivation layer 116 formed on the front surface including the interconnection and the thin film transistor, the contact layer having a contact hole, and a contact formed on the passivation layer, the drain electrode 115b of the thin film transistor, and formed in a sub-pixel including the transmission part T. An organic insulating film 160 having a concave-convex pattern by being embossed on the upper surface of the electrode 117, the reflecting portion R, and having a concave-convex pattern, and penetrating through the organic insulating film. A reflective electrode 124 is in contact over the transmission electrode 117 is provided.

In this case, an exposure mask is used to form the gate wiring layer, the semiconductor layer, the data wiring layer, the contact hole and the transparent electrode of the passivation layer, and a shadow mask is used to form the uneven pattern or the reflective electrode. By collectively patterning the semiconductor layer and the data wiring layer using a diffraction exposure mask, the number of times of use of the exposure mask can be further reduced.

Specifically, the photo-etching process using an exposure mask uses a principle of changing a property by causing a chemical reaction when a specific photoresist receives light, depositing a film on a substrate, and applying a photoresist thereon. Applying the light, selectively exposing the photoresist using ultraviolet wavelengths, developing the exposed photoresist, and etching the film using the developed photoresist as a mask. Step and the step of peeling off the photoresist, the process is complicated and cumbersome, the area occupied by the equipment is large, and process time and process costs are also consumed.

In contrast, a shadow mask has a frame designed to have an opening of a desired pattern. The process of printing a photoresist or a desired material through the opening forms the same pattern as the opening, which makes the process much easier and simpler than the photo etching process. There is an advantage.

With reference to Figures 3a to 8b will be described in more detail.

First, as shown in FIGS. 3A and 3B, copper (Cu), copper alloy (Cu Alloy), aluminum (Al), aluminum alloy (AlNd: Aluminum Neodymium), Metal materials, such as molybdenum (Mo), molybdenum alloy, chromium (Cr), chromium alloy, titanium (Ti), titanium alloy, silver (Ag), silver alloy, etc. Preferably, the sputtering method of the laminated film of molybdenum and AlNd After deposition in turn, patterning is performed by a photolithography process using an exposure mask to form the gate wiring 112, the gate electrode 112a in the TFT region branched from the gate wiring, and the capacitor lower electrode in the storage capacitor region Cst. 132 and the gate pad 122 of the gate pad portion region GP.

4A and 4B, an inorganic material such as silicon nitride (SiNx) or silicon oxide (SiOx) is deposited on the entire surface including the gate electrode 112a at a high temperature to form a gate insulating layer 113. do.

Subsequently, n + a-Si in which amorphous silicon (a-Si) and impurities are ion-implanted is laminated on the gate insulating layer 113, and copper (Cu), copper alloy (Cu Alloy), and aluminum ( Al), aluminum alloy (AlNd: Aluminum Neodymium), molybdenum (Mo), molybdenum alloy, chromium (Cr), chromium alloy, titanium (Ti), titanium alloy, silver (Ag), silver materials such as silver alloy sputtering ( Deposition by sputtering method.

Thereafter, a diffraction exposure mask is used to collectively pattern the laminated film of amorphous silicon, n + a-Si, and a metal material. Specifically, after applying a photo resist on the metal material, the photoresist is applied. The photoresist is exposed to UV or x-ray wavelengths by exposing a diffraction exposure mask (not shown) having a predetermined pattern formed thereon, and the exposed photoresist is developed to form a double-stage photoresist pattern.

Here, the diffraction exposure mask is formed of a metal light shielding layer and a semi-transparent layer on a transparent substrate, divided into three regions, a transparent region, a semi-transparent region, a light shielding region, the light transmittance is 100% in the transparent region, Silver has a light transmittance of 0% and a translucent region has a light transmittance of 0% to 100% or less to form a photoresist pattern in a double step.

Thereafter, the stacked layers of the amorphous silicon, n + a-Si, and metal materials are collectively etched using the double-stage photoresist pattern as a mask, thereby forming the data line 115, the semiconductor layer 114 of the TFT region, and the ohmic contact layer. The stacked film of 114a and the source / drain electrodes 115a / 115b and the data pad 125 of the data pad portion are formed. In this case, the source electrode and the drain electrode are integrally connected.

Next, the photoresist pattern is etched until the low stepped photoresist pattern is completely removed, and n + a-Si and metal material between the exposed source and drain electrodes are etched between the photoresist patterns and the source electrode and Disconnect the drain electrode. The semiconductor layer between the source electrode and the drain electrode becomes a channel region.

Thus, amorphous silicon 104 and n + a-Si 104a are provided under the data line 115 and the data pad 125 in the same pattern, and the source / drain electrodes 115a and 115b are disposed under the same pattern. An ohmic contact layer 114a having the same pattern as the drain electrode and formed of an n + a-Si material is provided, and a semiconductor layer 114 including a channel region is formed below the ohmic contact layer and formed of an amorphous silicon material. do.

Here, the gate electrode 112a, the gate insulating film 113 formed on the gate electrode, the semiconductor layer 114 formed on the gate insulating film on the gate electrode, and the source / drain electrodes formed on both ends of the semiconductor layer ( 115a and 115b constitute a thin film transistor, and in the case of a transflective liquid crystal display device, the thin film transistor is generally formed in a reflecting portion and overlapped by a reflecting electrode formed in a later process.

Subsequently, as illustrated in FIGS. 5A and 5B, the ashed photoresist pattern is completely removed and an inorganic insulating material such as silicon nitride (SiNx) or silicon oxide (SiOx) is deposited on the entire surface including the source / drain electrode. Alternatively, a protective film 116 is formed by applying an organic insulating material such as benzocyclobutene (BCB) or acrylic resin.

Subsequently, the gate insulating layer 113 or the protective layer 116 is selectively patterned by a photo etching process using an exposure mask to expose the first open region 152 and the data pad 125 to which the gate pad 122 is exposed. Forming a second open region 155 and a contact hole 118 through which the drain electrode 115b is exposed.

6A and 6B, transparent conductive materials such as indium tin oxide (ITO), indium zinc oxide (IZO), AZO, and ZnO are deposited on the entire surface including the passivation layer 116. Patterned by a photo-etching process using an exposure mask, a transmissive electrode 117 contacted to the drain electrode 115b and provided at a predetermined portion of a sub-pixel including a transmissive portion, integrally connected to the transmissive electrode, and the capacitor A capacitor upper electrode 135 overlapping the lower electrode 132, a first antioxidant film 162 contacting the gate pad 122, and a second antioxidant film 165 contacting the data pad 125 are formed. do.

The first and second antioxidant films prevent the gate pad and the data pad from being oxidized and improve the contact characteristics between the gate pad and the data pad and the external driving circuit.

Subsequently, as shown in FIGS. 7A and 7B, the first shadow mask (501 in FIG. 9) is disposed on the substrate on which the transmission electrode 117 is formed, and then BCB (Benzocyclobutene) is sprayed. ) And an organic insulating material such as an acrylic resin is unevenly coated to form an organic insulating film 160 having a rough uneven pattern 160a on the surface thereof.

The spray method is a method of spraying an organic insulating material while scanning the spray nozzle from one edge of the substrate to the other edge while the shadow mask is covered.

The organic insulating material includes a thermosetting insulating material and a photocurable insulating material, the thermosetting insulating material is cured by heat, and the photocurable insulating material is cured by light, in particular UV. When the thermosetting insulating material is used, thermosetting may be performed while the first shadow mask is covered, but when the thermosetting insulating material is used, photocuring is performed with the first shadow mask removed. After the photocuring, hard bake is additionally performed.

At this time, the uneven pattern is not a hemispherical shaped pattern, but the surface becomes rough when the organic insulating film is unevenly applied by the spray method. Thus, the rough surface plays the same role as the uneven pattern. When the external natural light is used as the light source, the surface of the organic insulating layer may be rough so as to locally change the reflection angle of the external natural light to widen the viewing angle, and thus it may not need to be a pattern in which the uneven pattern is conventional.

As shown in FIG. 9, the first shadow mask 501 has a frame 502 designed to have openings 500a and 500b in a region corresponding to a reflecting portion, and the first shadow mask is disposed. Then, when the organic insulating material is applied by a spray method, an organic insulating film having a rough surface thereof is formed in the openings 500a and 500b. At this time, by designing an open area in a structure in which a plurality of circles overlap each other, such as 500b, an organic insulating film may be formed to have the same effect as a conventional hemispherical uneven pattern.

Next, as shown in FIGS. 8A and 8B, after the second shadow mask (503 of FIG. 10) is disposed on the substrate on which the rough surface of the organic insulating film 160 is formed, the vapor deposition method is performed. The reflective material is deposited to limit the reflective portion to form the reflective electrode 124. At this time, the reflective electrode is formed in a larger pattern than the organic insulating film so as to be in contact with the transmissive electrode, and is formed along the organic insulating film 160 having the rough uneven pattern 160a on the surface. Reflective irregularities are formed.

The reflective material is a metal having high reflectance, for example, aluminum (Al), aluminum alloy (AlNd), copper (Cu), silver (Ag), molybdenum (Mo), chromium (Cr), titanium (Ti), tantalum (Ta) , Molybdenum-tungsten (MoW) and the like can be used.

As shown in FIG. 10, the second shadow mask 503 has a frame 504 in which an area corresponding to the reflection part R is open. The second shadow mask 503 is formed by depositing a reflective material in the open area. The reflective electrode is formed in the same manner as the pattern of the region. In order for the reflective electrode to contact the transmissive electrode, the reflective electrode must be larger than the size of the organic insulating layer. Therefore, the open area of the second shadow mask for forming the reflective electrode should be wider than the open area of the first shadow mask for forming the organic insulating film. .

In the above-described embodiment, the shadow mask is used in all the steps of forming the organic insulating film and forming the reflective electrode. However, the present invention is not limited thereto, and the shadow mask is used only in the step of forming the organic insulating film or the reflective electrode is formed. You can only use shadow masks.

The TFT array substrate thus formed is oppositely bonded to the color filter layer array substrate with the liquid crystal layer interposed therebetween. Although not shown, the color filter layer array substrate shields light leakage in an area where the separation between R, G, and B cells and the electric field is unstable. A black matrix, a red, green, and blue color filter layers arranged in a predetermined order for each unit pixel to implement colors, and the color filter layers of the R, G, and B colors. An overcoat layer is formed to planarize the surface, and a common electrode is formed to form an electric field for controlling the liquid crystal opposite to the transmission electrode and the reflection electrode.

On the other hand, the present invention described above is not limited to the above-described embodiment and the accompanying drawings, it is possible that various substitutions, modifications and changes within the scope without departing from the technical spirit of the present invention. It will be apparent to those of ordinary skill in Esau.

The method of manufacturing a transflective liquid crystal display device according to the present invention as described above has the following effects.

First, an exposure mask is used to form the contact hole and the transmission electrode of the gate wiring layer, the semiconductor layer, the data wiring layer, the passivation layer, and a shadow mask is used to form the uneven pattern or the reflective electrode. Can be reduced twice.

In addition, by collectively patterning the semiconductor layer and the data wiring layer using a diffraction exposure mask, the number of times of use of the exposure mask can be further reduced.

As a result, the process time and the process cost are drastically reduced because the photo-etching process does not need to be performed up to two or three times.

Second, in the prior art in which the transmissive electrode was formed on the reflective electrode, the yield of the reflective electrode was torn during wet etching to form the transmissive electrode. As the deposition method completes the patterning and does not perform a separate wet etching, the reduction of the yield is improved.

Claims (10)

Forming a sub-pixel divided into a reflecting portion and a transmitting portion by vertically forming a gate line and a data line on the substrate, and forming a thin film transistor at an intersection point of the two lines; Forming a transmission electrode contacting the transmission part to a drain electrode of the thin film transistor in a predetermined region; Disposing a first shadow mask having an opening in the reflecting portion and unevenly applying an organic insulating material to form an organic insulating film having a rough surface; And forming a reflective electrode in contact with the transmissive electrode on the organic insulating film. The method of claim 1, A method of manufacturing a transflective liquid crystal display device, characterized in that to form an organic insulating film and a reflective electrode in order to the reflective portion above the transmissive electrode. The method of claim 1, The organic insulating material is a method of manufacturing a transflective liquid crystal display device, characterized in that the coating in a spray method. The method of claim 1, The first shadow mask is a method of manufacturing a transflective liquid crystal display device, characterized in that the opening of the plurality of circular overlapping shape is formed. The method of claim 1, And the reflective electrode is formed by disposing a second shadow mask having an opening in the reflective portion and depositing a reflective material. The method of claim 5, wherein The reflective material is a method of manufacturing a transflective liquid crystal display device, characterized in that the deposition by vapor deposition method. The method of claim 5, wherein The opening of the second shadow mask is larger than the opening of the first shadow mask. The method of claim 1, And the organic insulating layer is formed of a thermosetting material or a photocuring material. Forming a sub-pixel divided into a reflecting portion and a transmitting portion by vertically forming a gate line and a data line on the substrate, and forming a thin film transistor at an intersection point of the two lines; Forming a transmission electrode contacting the transmission part to a drain electrode of the thin film transistor in a predetermined region; Forming an organic insulating film having an uneven pattern on the reflecting portion; And placing a shadow mask on the organic insulating layer and depositing a reflective material to form a reflective electrode in contact with the transmissive electrode. The method of claim 9, The reflective material is a method of manufacturing a transflective liquid crystal display device, characterized in that the deposition by vapor deposition method.

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