KR100487783B1 - Fabrication method of an array substrate having a reflective plate for a liquid crystal display device - Google Patents

Abstract

The present invention relates to a method for manufacturing an array substrate for a reflective or reflective transmissive liquid crystal display device.

In the structure of a conventional reflective and semi-transmissive liquid crystal display array substrate, an uneven reflecting plate is formed inside a cell in order to increase reflection performance. At this time, when forming the concavities and convexities, concave concavities and convexities are generally formed by forming a convex concave-convex structure using a photoacryl photosensitive organic film or by stamping through a die pressing process. However, the convex convex and concave convex concave and convex concave convex concave and concave convex concave and concave convex concave and convex concave and convex concave and convex concave and convex concave and convex concave and convex concave and convex concave and convex concave and convex concave and convex concave and convex concave and concave concave and convex concave and convex concave and concave concave and convex concave and convex concave and concave convex concave and concave convex concave and convex concave and concave convex concave

In the present invention, the concave-convex structure is formed by using an inorganic insulating material of BCB or silicon nitride, which is used as an organic film for general liquid crystal display devices, to form irregularities. Reflective or transflective liquid crystal display devices can be manufactured.

Description

Fabrication method of an array substrate having a reflective plate for a liquid crystal display device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a reflective plate, wherein a liquid crystal display device having a reflection plate includes a reflective liquid crystal display device and a transflective liquid crystal display device, and more particularly, to the formation of the uneven structure of the reflective plate in such an array substrate. will be.

Recently, with the rapid development of the information society, the necessity of a flat panel display having excellent characteristics such as thinning, light weight, and low power consumption has emerged.

Such a flat panel display can be divided according to whether it emits light by itself or not. A light emitting display device that emits light by itself is called a light emitting display device. It is called a display device. The light emitting display includes a plasma display panel, a field emission display, an electroluminescence display, and the light receiving display includes a liquid crystal display. There is).

Among them, liquid crystal display devices are being actively applied to notebooks and desktop monitors because of their excellent resolution, color display, and image quality.

In general, a liquid crystal display device is formed by arranging two substrates on which electric field generating electrodes are formed so that the surfaces on which two electrodes are formed face each other, injecting a liquid crystal material between the two substrates, and then applying a voltage to the two electrodes. By moving the liquid crystal molecules by the electric field, it is a device that represents the image by controlling the transmittance of the light is changed accordingly.

However, the liquid crystal display device does not emit light as described above, so a separate light source is required.

Therefore, an image is displayed by arranging a backlight on the back of the liquid crystal panel and injecting light from the backlight into the liquid crystal panel to adjust the amount of light according to the arrangement of the liquid crystals. In this case, the field generating electrode of the liquid crystal display device is made of a transparent conductive material, and both substrates should also be made of a transparent substrate.

Such a liquid crystal display device is called a transmission type liquid crystal display device. Since the liquid crystal display device uses an artificial back light source such as a backlight, a bright image can be realized even in a dark external environment, but power consumption due to the backlight is consumed. There is a big disadvantage.

In order to compensate for the above disadvantages, a reflection type liquid crystal display device has been proposed. The reflection type liquid crystal display device has less power consumption than the transmission type liquid crystal display device in the form of controlling light transmittance according to the arrangement of liquid crystals by reflecting external natural light or artificial light. In the reflective LCD, the lower field generating electrode is formed of a conductive material that reflects well, and the upper field generating electrode is formed of a transparent conductive material to transmit external light.

Hereinafter, a reflective liquid crystal display device and a reflective transmissive liquid crystal display device will be described as an example of a liquid crystal display device having a reflective plate with reference to the accompanying drawings.

1 is a cross-sectional view of a part of a typical reflective liquid crystal display device.

As shown in the drawing, a gate electrode 12 is formed on the first substrate 11, and a gate insulating film 13 is formed thereon. A gate wiring (not shown) connected to the gate electrode 12 is further formed below the gate insulating layer 13. Next, the active layer 14 and the ohmic contact layers 15a and 15b are sequentially formed on the gate insulating film 13 on the gate electrode 12. Source and drain electrodes 16b and 16c are formed on the ohmic contact layers 15a and 15b, and the source and drain electrodes 16b and 16c form a thin film transistor together with the gate electrode 12.

On the other hand, a data line 4 made of the same material as the source and drain electrodes 16b and 16c is formed on the gate insulating layer 13, and the data line 4 is connected to the source electrode 16b. The data line 4 intersects the gate line to define a pixel region. Next, a protective layer 17 made of an organic material is formed on the data line 4 and the source and drain electrodes 16b and 16c to cover the thin film transistor T, and the protective layer 17 It has a contact hole 17a exposing the drain electrode 16c.

Subsequently, a reflective electrode 18 is formed in the pixel region above the passivation layer 17 and is connected to the drain electrode 16c through the contact hole 17a. Here, the reflective electrode 18 is made of a conductive material such as a metal, and is formed of a concave-convex type having a scattering function in order to increase the reflectance at an effective viewing angle of the user, covering the thin film transistor T, and the data line 4. In this case, the aperture ratio can be improved, and the protective layer 17 is formed of an organic material having a low dielectric constant so that signal interference does not occur between the reflective electrode 18 and the data line 4.

On the other hand, a black matrix 22 is formed on the inner surface of the second substrate 21, and a color filter in which red (R), green (G), and blue (B) are sequentially repeated at the bottom thereof ( 23a, 23b, and 23c are formed, and a common electrode 24 made of a transparent conductive material is formed under the color filters 23a, 23b, and 23c. Here, the color filters 23a, 23b, and 23c have one color corresponding to one reflective electrode 18, and the black matrix 22 is formed at a position corresponding to the edge of the reflective electrode 18. As mentioned above, since the reflective electrode 18 made of an opaque conductive material such as a metal covers the thin film transistor T, the black matrix 22 may be formed to cover only the edge of the reflective electrode 18.

Next, the liquid crystal layer 30 is positioned between the reflective electrode 18 and the common electrode 24, and the voltage of the liquid crystal molecules of the liquid crystal layer 30 is applied to the reflective electrode 18 and the common electrode 24. The arrangement state is changed by the electric field generated between the two electrodes 18 and 24. Although not illustrated, an alignment layer is formed on the reflective electrode 18 and the common electrode 24, respectively, to determine the initial arrangement state of the liquid crystal molecules.

As described above, in the reflective liquid crystal display device, the reflective electrode is formed of a material having good reflection to reflect light incident from the outside to express an image. Therefore, power consumption can be reduced and used for a long time.

In addition, irregularities are formed on the upper surface of the protective layer 17 so that the surface of the reflective electrode 18 has an irregular shape. Therefore, the front brightness can be improved by changing the angle of the reflected light.

Referring to FIG. 2, which is a cross-sectional view of a reflective liquid crystal display device array substrate including an uneven reflection plate, a method of manufacturing a conventional array substrate for a general reflective liquid crystal display device including a process of forming such unevenness will be described.

The process of forming the source and drain electrodes is the same as in the conventional liquid crystal display device and will be omitted.

As shown in FIG. 2B, an organic material is coated on the protective layer 17 of the substrate on which the thin film transistor is formed to form the first organic layer 31. This organic material is formed of a photosensitive material, for example photoacrylic. This is because there is no need to use a separate photoresist to pattern the organic material.

As shown in FIG. 2B, when the substrate is exposed and developed using a mask, the photosensitive organic material is removed after etching, a sawtooth organic film pattern 33 having a predetermined interval and size is formed. At this time, it is possible to adjust the inclination angle of the concavities and convexities formed afterwards by adjusting the interval and the degree of overlap between the patterns 32. Such organic materials may cause the portions that are not illuminated to be removed or may be such that the portions that are not illuminated are removed.

Next, as shown in FIG. 2C, the organic layer pattern 33 is heat-treated to form an uneven organic layer pattern 35. At this time, the organic layer pattern 35 is melted and spread by heat treatment, and is then cured to have an inclination angle and form a gentle bend.

Subsequently, as shown in FIG. 2D, an organic material is coated on the entire surface of the protective layer 17 on which the uneven organic film pattern 35 is formed to form the second organic film 37. Here, the second organic film 37 adjusts the contour formed by the uneven organic film pattern 35 to form a curved surface having an inclination angle.

Next, as shown in FIG. 2E, the protective layer 17 is patterned using a mask to form a drain contact hole 17a exposing the drain electrode 16c.

Lastly, as shown in FIG. 2F, a reflective plate 18 is formed in the pixel region above the second organic layer 35 to reflect light using a mask. In this case, the reflecting plate forms the reflecting electrode 18.

As mentioned above, in the produced convex reflection plate, the convex concave-convex shape was made of photoacrylic which is a photosensitive resin. However, since the photoacryl is not used in a transmissive liquid crystal display device, it cannot be configured using existing equipment. This requires different investment in equipment to form a new developing line because the developer of photoacryl is different. The above-described convex reflection plate may be manufactured using dry etching of BCB, in addition to the method of forming by heat treatment of the photoacryl.

3A to 3D are cross-sectional views of forming a convex reflective plate using dry etching of BCB. The thin film transistor formation is omitted because it proceeds in the same manner as the general method.

As shown in FIG. 3A, BCB is applied to a switching element including a source and a drain electrode to form a first organic film 52. Subsequently, an exposure and development process are performed on the substrate 50 on which the first organic layer 52 is formed by using a mask to form a PR pattern 55 at a predetermined interval.

Next, as shown in FIG. 3B, dry etching is performed on the substrate 50 on which the PR pattern 55 is formed to form an organic layer seed 57 having a predetermined interval and an inclination angle.

Next, as illustrated in FIG. 3C, BCB is coated on the organic layer seed 57 to form a second organic layer 59. In this case, the second organic layer 59 forms a protective layer 59, and the second organic layer 59 has a convex convex-concave shape by the lower organic layer seed 57. Thereafter, the protective layer 59 is patterned using a mask to form the drain contact hole 60.

Next, a reflective plate 61 is formed on the protective layer 59 to contact the drain electrode of the switching device through the drain contact hole 60. The reflective plate 61 forms a reflective electrode.

However, as described above, when convex unevenness is formed by using BCB and dry etching, the planar mirror component becomes much larger in the section between the organic film seed 57 and the seed, and the reflectance in the effective viewing angle is not good. When the PR pattern (55 in FIG. 3A) is transferred to the BCB in the dry etching process in which the CD loss and the PR are transferred to the BCB after the development of the PR, the dry etching occurs not only in the vertical direction but also in the horizontal direction. This is because the plane space between) increases.

The present invention has been made to solve the problems of the prior art as described above, an object of the present invention is to use a concave-convex concave-convex using BCB which is a general organic insulating material or concave using a silicon nitride of inorganic insulating material It is to provide a method of manufacturing a reflector having a high reflection efficiency by configuring a reflector having a concave-convex structure.

      In order to achieve the above object, the present invention is to form a concave-convex organic film pattern using an organic material such as benzocyclobutene or an inorganic material of silicon nitride.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention;

First Embodiment

In the first embodiment of the present invention, a concave reflector structure is formed by using benzocyclobutene (BCB), which is generally used as an insulating material in the manufacture of an array substrate of a liquid crystal display device.

4 is a cross-sectional view of an array substrate for a reflective liquid crystal display device including an uneven reflecting plate according to the present invention. Switching including a gate electrode and a semiconductor layer 106, and source and drain electrodes 108 and 110 on a substrate 100. An element is formed, and the first organic layer 113 is formed on the entire surface of the substrate 100 to cover the switching element. Concave-convex 117 is formed in the first organic layer 113, and a second organic layer 119 is formed on the first organic layer 113 in which the concave-convex concave-convex 117 is formed. The first and second organic layers 113 and 119 are patterned to form drain contact holes 121 exposing the drain electrodes 110. The first and second organic layers 113 and 119 are formed in contact with the drain electrodes 110 through the drain contact holes 121. A reflective plate 123 made of a metal material is formed on the second organic layer 119. The reflection plate 123 forms a reflection electrode.

5A to 5D are manufacturing process diagrams of an array substrate for a reflective liquid crystal display device according to a first embodiment.

First, as shown in FIG. 5A, the gate electrode 102 is formed on the substrate 100. A metal material such as chromium, copper, and aluminum is deposited on the substrate 100, the PR is applied thereon, and the PR is exposed, developed, etched, and removed using a mask having a pattern formed in the form of a gate electrode 102. The gate electrode 102 is formed.

Thereafter, the gate insulating layer 104 is formed on the substrate 100 on which the gate electrode 102 is formed. At this time, a silicon nitride film (SiNx) or a silicon oxide film (SiO ₂ ) is used as the gate insulating film 104.

Next, an active layer 106a of amorphous silicon and an ohmic contact layer 106b of amorphous silicon containing impurities are formed on the gate insulating layer 104 on the gate electrode 102. Here, the active layer 106a is formed by depositing and patterning a silicon layer, and the ohmic contact layer 106b is formed by ion doping with phosphorus or boron as impurities in the active layer.

Next, a source electrode 108 and a drain electrode 110 are formed on the ohmic contact layer 106b. Here, the metal material is deposited and patterned through a mask process to form the source and drain electrodes 108 and 110. Meanwhile, the active layer 106a and the ohmic contact layer 106b are formed, and the source and drain electrodes 108 and 110 are formed thereon, and then exposed in a region spaced between the source and drain electrodes 108 and 110. The ohmic contact layer is removed to expose the active layer 106a underneath to form a channel region. In this case, since the source and drain electrodes 108 and 110 are used as masks, a separate mask is not necessary.

Next, as shown in FIG. 5B, the first organic layer 113 is formed by coating BCB, which is an organic material, on the substrate 100 on which the thin film transistor including the source and drain electrodes 108 and 110 is formed. . Thereafter, after the entire surface of the PR is coated on the first organic layer 113, a mask process is performed to expose, develop, and etch to form the PR patterns 115 at the same interval. The shape of the PR pattern 115 is formed so that its cross section has a polygonal or semi-circular, semi-elliptic cross section such as pentagonal, hexagonal, trapezoidal, etc., wherein the spacing W between the PR pattern 115 and the pattern is 4 μm to It should be formed between 30㎛. In addition, the size and spacing (W) of the PR pattern 115 should be formed in consideration of the fact that the fraudulent PR pattern due to CD loss (usually 1 μm on both sides of the left and right sides) during development of the PR pattern 115 differs from the actual design value. .

Next, as shown in FIG. 5C, the substrate 100 on which the PR pattern 115 is formed is subjected to dry etching. When the dry etching is performed, the dry etching proceeds in the horizontal direction while the dry etching proceeds in the vertical direction. Therefore, when the thickness of the PR pattern 115 is adjusted, concave dimple-shaped concave-convex 117 having a size of 8 µm to 34 µm is finally formed. In addition, the final height of the concave-convex and concave-convex 117 is formed in a ratio of 1:10 to 1:30, the thickness of the remaining BCB is 0.7㎛. At this time, the dry etch selectivity of the PR and BCB in the vertical direction may be selected by the adjustment of the dry etching conditions.

Next, as shown in FIG. 5D, BCB is entirely deposited on the first organic film 113 having the dimple-shaped unevenness to form the second organic film 119. Thereafter, a drain contact hole is formed on the organic layers 113 and 119 through the mask process to expose the drain electrode. Thereafter, a reflective plate 123 is formed on the second organic layer 119 having the drain contact hole 121. The reflecting plate forms a reflecting electrode.

6 is a cross-sectional view of an array substrate for a transflective liquid crystal display device according to a first embodiment. Since the formation process of the concave-convex irregularities is described through the manufacturing process of the array substrate for the reflective liquid crystal display device of FIGS. 5A to 5D, the above process is omitted.

As illustrated, after the concave and convex concave and convex 154 are formed on the first organic layer 152 of the substrate 150 on which the switching element is formed, the reflective plate 156 is disposed on the organic layer 152 on which the concave and convex concave and convex 154 is formed. Form. At this time, in order to improve the luminance of the transmission region, after removing the first organic layer 152 formed in the transmission region portion, and including the first organic layer 152 of the reflection portion to form the transmission electrode 160, The inorganic insulating material layer 158 is formed to the region where the first organic film is removed, and then a metal material is deposited on the inorganic insulating material layer 158 to form the pixel electrode 160.

In the reflective or semi-transmissive liquid crystal display device manufactured by the above-described method, the use of BCB using the reflection plate in a general liquid crystal display device was used to form a dimple-shaped unevenness which is effective in securing an effective viewing angle and excellent in reflection efficiency. It has better reflection efficiency than the convex concave-convex method using conventional photoacryl, and has a finer structure than the conventional dimple type concave-convex method using a mold press. The array substrate for a transflective liquid crystal display device can be manufactured.

Second Embodiment

According to a second embodiment of the present invention, a dimple-shaped concave-convex structure having excellent reflection efficiency is formed of silicon nitride, which is an inorganic insulating material, and is provided by wet etching.

7A to 7D are cross-sectional views illustrating a reflective plate formed by wet etching silicon nitride in an array substrate for a reflective liquid crystal display device according to a second embodiment of the present invention.

First, as shown in FIG. 7A, the gate electrode 202 and the gate insulating layer 204 and the gate insulating layer 204 and the active layer 206a and the ohmic contact layer 206b are disposed on the substrate 200. Source and drain electrodes 208 and 210 are formed on the semiconductor layer 206 and the semiconductor layer 206 to form a thin film transistor.

Next, silicon nitride, which is an inorganic insulating material, is deposited on the entire surface of the substrate 200 on which the source and drain electrodes 208 and 210 are formed. Thereafter, PR is applied onto silicon nitride deposited on the entire surface of the substrate 200. Thereafter, the mask is exposed and developed to form a PR pattern 214.

The structure of the mask 300 will be described with reference to FIG. 8. As shown, the mask 300 is formed such that the distance between the intaglio pattern 302 is 1 μm to 2 μm, and the intaglio pattern 302 is 2 μm to 20 μm. The mask is exposed and developed to form a PR pattern. The intaglio pattern 302 of the mask is made of various patterns such as circle, ellipse, hexagon.

Next, as shown in FIG. 7C, wet etching is performed on the substrate 200 on which the PR pattern 214 is formed. In this case, since the silicon nitride is etched on the side surface of the silicon nitride, the concave-convex structure is formed on the inorganic insulating film of the silicon nitride by appropriately adjusting the wet etching conditions.

Next, as shown in FIG. 7D, a mask process is performed on the concave and convex uneven substrate 200 to form a drain contact hole 220, and at the same time, a drain electrode 210 through the drain contact hole 220. ) Is formed on the inorganic insulating film of the dimple type unevenness forming.

In the above-described method, after the source and drain electrodes are formed, an organic film is formed on the source and drain electrodes using BCB, which is an organic insulating material, and then, as in the above-described second embodiment, an inorganic film of silicon nitride is formed and a wet etching process is performed. As a result, concave and convex unevenness may be formed.

Although not shown, in the case of a transflective liquid crystal display device, a reflective plate is formed on an inorganic insulating film having concave-convex irregularities, an inorganic insulating material is formed thereon, and a contact between the drain electrode and the drain contact hole is formed on the inorganic insulating material layer. A transmissive electrode is formed.

As described above, in the case of fabricating an array substrate for a reflective or reflective transmissive liquid crystal display device according to preferred embodiments of the present invention, the following characteristics are present. When the concave-convex reflector is formed of a protective layer of an existing LCD, a BCB, which is an organic insulating film, or silicon nitride, which is an inorganic insulating material, is used to form concave-convex structures, thereby improving reflection performance. In addition to the improvement, BCB or silicon nitride, which is used as an insulating film of a conventional liquid crystal display device, is used to form irregularities, and thus a reflective or semi-transmissive liquid crystal display device can be manufactured using the production line of a general liquid crystal display device as it is. Has an effect.

1 is a cross-sectional view of a typical reflective liquid crystal display device.

2A to 2F are cross-sectional views of a manufacturing process of an array substrate for a reflective liquid crystal display device having a convex uneven structure reflecting plate of photoacryl;

3A to 3C are cross-sectional views of fabricating an array substrate for a reflective liquid crystal display device having a convex uneven structure reflecting plate using dry etching of BCB.

4 is a cross-sectional view of an array substrate for a liquid crystal display device of the present invention.

5A to 5D are sectional views of the manufacturing process of the array substrate for the reflective liquid crystal display device having the concave-convex reflective plate using the BCB of the first embodiment of the present invention. .

6A to 6D are cross-sectional views illustrating a fabrication process of an array substrate for a reflective liquid crystal display device having a concave-convex reflective plate using a silicon nitride according to a second embodiment of the present invention. 6 is a cross-sectional view of an array substrate for a transflective liquid crystal display device according to a first embodiment of the present invention. FIGS. A cross-sectional view of the manufacturing process of an array substrate for a liquid crystal display device. DESCRIPTION OF REFERENCE NUMERALS OF THE DRAWINGS 100: substrate 106 semiconductor layer 108 source electrode 110 drain electrode 113 first organic film 117 concave-convex unevenness 119 second organic film 121 drain contact hole 123 Reflector

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Claims (9)

Forming a switching element comprising a gate electrode, a semiconductor layer, and a source and a drain electrode on the transparent insulating substrate; Forming a first insulating film on the substrate on which the switching element is formed; Forming a plurality of photoresist patterns spaced apart from each other on the first insulating film; Etching the first insulating layer using the photoresist pattern as a mask to form concave and convex structures; Forming a reflective plate by depositing a metal material on the first insulating layer on which the concave-convex irregularities are formed Method of manufacturing an array substrate for a liquid crystal display device comprising a. The method of claim 1, And the first insulating film is an organic insulating film such as benzocyclobutene (BCB). The method of claim 1, And the first insulating film is an inorganic insulating film such as silicon nitride or silicon oxide. The method of claim 1, The method of manufacturing an array substrate for a liquid crystal display device, characterized in that the interval between the photoresist pattern is formed from 6㎛ to 32㎛. The method of claim 1, The ratio of the vertical height and the horizontal length of the concave-convex concave-convex structure is formed from 1:10 to 1:30. The method of claim 1, And forming a transparent pixel electrode connected to the switching element at an upper portion after the reflection plate is formed. The method of claim 1, And the reflecting plate is connected to the switching element. The method of claim 1, And a second insulating film is further formed between the first insulating film and the reflecting plate. The method of claim 8, And the second insulating film is an inorganic insulating film.