KR100381864B1 - Reflective liquid crystal display device and its manufacturing method - Google Patents

Abstract

A gate pattern and a storage electrode line parallel to the gate line are formed on the insulating substrate in the horizontal direction, the gate pattern and the gate electrode being the branch of the gate line. On the gate insulating layer covering the gate pattern and the storage electrode line, a data pattern including a source / drain electrode connected to the semiconductor layer and a data line formed in the vertical direction to define the gate line and the unit pixel area is formed. In addition, a storage electrode is formed on the gate insulating film above the storage electrode line, and the storage electrode is connected to the drain electrode through the connection portion. A passivation film having a contact hole for exposing the drain electrode is formed on the upper portion of the data pattern and the data pattern. A reflecting film connected to the drain electrode is formed on the upper portion of the passivation film. R, G, and B color filters are formed. Here, the protective film may be formed of an organic insulating film or a black matrix material that is excellent in absorbing light and made of a material having high resistance. In this structure, the black matrix is exposed by the reflective film, so that the portion where the image is displayed becomes the entire reflective film. Therefore, the aperture ratio and the reflectance become maximum, and the black matrix blocks light incident on the semiconductor layer of the thin film transistor. In addition, a color filter is formed directly on the reflective film to improve color purity and contrast ratio.

Description

Reflective Liquid Crystal Display and Manufacturing Method Thereof

The present invention relates to a liquid crystal display device, and more particularly, to a reflective liquid crystal display device.

In general, a liquid crystal display includes a pair of transparent glass substrates on which transparent electrodes are formed, a liquid crystal material between two glass substrates, two polarizers attached to an outer surface of each glass substrate to polarize light, and a light emitting device that emits light. It consists of a back light.

On the other hand, recently, a reflective liquid crystal display device without back night has been developed.

Next, a structure of a reflective liquid crystal display according to the related art will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view schematically illustrating a structure of a reflective liquid crystal display device according to the related art.

As shown in FIG. 1, the conventional reflective liquid crystal display device is composed of two substrates 1 and 11 facing each other and a liquid crystal layer 111 injected between the two substrates 1 and 11.

A gate electrode 2 is formed on the lower substrate 1, and a gate insulating film 3 covering the gate electrode 2 is formed on the lower substrate 1. The semiconductor layer 4 is formed on the gate insulating film 3 corresponding to the gate electrode 2, respectively, and the source / drain electrode facing the gate electrode 2 on the semiconductor layer 4. 61 and 62 are formed, respectively. Resistive contact layers 51 and 52 are formed between the source and drain electrodes 61 and 62 and the semiconductor layer 4, respectively, and have an opening on the drain electrode 62 above the lower substrate 1. The protective film 7 is formed. A reflective film 8 connected to the drain electrode 62 is formed in an upper portion of the protective film 7, and a reflective film 8 is formed on the protective film 7 exposed by the reflective film 8 and the reflective film 8. The planarization film 9 is formed in order to prevent the nonuniform orientation by the unevenness | corrugation which a) has.

Meanwhile, R, G, and B color filters 13 are formed on the upper substrate 11 corresponding to the reflective film 8 of the lower substrate 1, and a black matrix is formed between the R, G, and B color filters 13. 15 is formed, and a common electrode 17 is formed on the entire surface of the upper substrate 11 on the R, G, B color filters 13 and the black matrix 15.

In general, the upper substrate 11 is referred to as a color filter substrate, and the lower substrate 1 is formed of a thin film transistor including a gate electrode 2, a source / drain electrode 61 and 62, and a semiconductor layer 4. It is called a substrate.

In the conventional reflective liquid crystal display device, the light incident on the upper substrate 11 passes through the liquid crystal layer 111 and is reflected by the reflective film 8 of the lower substrate 1 to again form the liquid crystal layer 111 and Passes through the upper substrate 11.

However, the conventional reflective liquid crystal display device has a problem in that the contrast ratio is reduced due to reflection by the black matrix 15 of the upper plate 11 or reflection between the black matrix 15 and the reflective film 8. In addition, since the reflecting film 8 and the black matrix 15 are formed to overlap each other in consideration of misalignment, the aperture ratio and reflectance of the pixel are reduced, and due to light incident obliquely between the reflecting film 8 and the reflecting film 8, A light leakage current is generated in the thin film transistor to degrade the characteristics of the device. In addition, a problem arises in that the color purity and contrast ratio due to mutual interference of each of the R, G, and B color filters 13 are lowered due to the light incident obliquely from the upper plate 11. In the case of widening of the width, the area of the reflective film 8 exposed by the black matrix is reduced, thereby reducing the reflectance and the aperture ratio.

An object of the present invention is to improve color purity, contrast ratio, aperture ratio and reflectance of a reflective liquid crystal display device.

In addition, another object of the present invention is to block the light leakage current of the thin film transistor in the reflective liquid crystal display device.

In addition, another object of the present invention is to simplify the manufacturing process of the reflective liquid crystal display device.

1 is a cross-sectional view schematically illustrating a structure of a reflective liquid crystal display device according to the related art.

2 is a layout view illustrating a structure of a thin film transistor substrate for a reflective liquid crystal display device according to an exemplary embodiment of the present invention.

3 is a cross-sectional view taken along the line III-III of FIG. 2,

4 and 5 illustrate a method of manufacturing a thin film transistor substrate for a reflective liquid crystal display according to an exemplary embodiment of the present invention.

In the thin film transistor substrate for a reflective liquid crystal display device according to the present invention for achieving such a problem, the planarized R, G, B color filters are formed on the reflective film.

More specifically, a gate pattern formed of a gate line and a gate electrode which is a branch of the gate line is formed on the substrate, and a gate insulating film covering the gate pattern is formed. A data pattern is formed on the gate insulating layer, the data pattern including a data line defining a pixel region crossing the gate line, a source electrode which is a branch of the data line, and a drain electrode which faces the source electrode around the gate electrode. The protective film which has the contact hole which exposes a drain electrode is formed in the part which is not. A reflective film connected to the drain electrode through the contact hole is formed in the pixel area above the passivation film, and R, G, and B color filters are formed on the reflective film.

In the method of manufacturing such a reflective liquid crystal display, first, a gate pattern including a gate line and a gate electrode and a gate insulating film covering the gate pattern are formed on the substrate. Next, a semiconductor layer is formed on the gate insulating layer corresponding to the gate electrode, and a data pattern including a data line defining a pixel region intersecting the gate line and a source / drain electrode connected to the semiconductor layer is formed on the gate insulating layer. Form. Next, a protective film is formed on the substrate, and the protective film is etched to form a contact hole exposing a part of the drain electrode. A conductive material having a reflectance is stacked and patterned on the upper portion of the passivation layer to form a reflecting layer connected to the drain electrode, and R, G, and B color filters are formed on the reflecting layer.

In this case, the protective film may be formed of an organic insulating film, or may be formed of a material for a black matrix.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of a reflective liquid crystal display and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains may easily implement the present invention.

In the thin film transistor substrate for a liquid crystal display device and the manufacturing method thereof according to the embodiment of the present invention, a color filter is formed on the reflective film.

2 is a layout view illustrating a structure of a thin film transistor substrate for a reflective liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 2. 3 shows an additional color filter substrate.

As shown in FIG. 2 and FIG. 3, in the reflective liquid crystal display according to the exemplary embodiment of the present invention, the gate line 200 and the gate line 200 transmitting scan signals in the horizontal direction on the first insulating substrate 100 are provided. The gate pattern formed of the gate electrode 210, which is a branch of the s, is formed, and the storage electrode line 220 is formed to receive the common signal in parallel with the gate line 200 to form the storage capacitor.

A gate insulating film 300 made of silicon nitride or the like is formed on the gate patterns 200 and 210 and the storage electrode line 220, and a thin film transistor made of amorphous silicon or the like is formed on the gate insulating film 300 on the gate electrode 210. The semiconductor layer 400 is formed. On the semiconductor layer 400, resistance contact layers 510 and 520, which are divided into both sides with respect to the gate electrode 210 and made of doped amorphous silicon, are formed.

The source electrode 610 and the drain electrode 620 are formed on each of the ohmic contacts 510 and 520, respectively. Here, the source electrode 610 is a branch of the data line 600 formed in the vertical direction on the gate insulating film 300 to transfer the image signal, and the unit pixel is formed by the intersection of the gate line 200 and the data line 600. Region P is defined. In addition, the storage electrode 640 is formed on the gate insulating layer 300 on the storage electrode line 220, and the storage electrode 640 is connected to the drain electrode 620 through the connection portion 630.

On the data patterns 600, 610, and 620, the storage electrode 640, and the gate insulating layer 300, a passivation layer 700 made of an organic material for black matrix having high insulating property and high insulation is formed. In the passivation layer 700, a contact hole 710 exposing the drain electrode 620 is formed.

In this case, when the material for the black matrix of the protective film 700 has a low insulating property, an insulating film made of silicon nitride or silicon oxide is added to the upper and / or lower portions of the material for the black matrix to reinforce the insulating film. Can be formed.

In addition, the protective film 700 may be formed of silicon nitride or silicon oxide, or may be formed of an organic insulating film having excellent planarization.

The upper pixel region P of the passivation layer 700 is connected to the drain electrode 620 through a contact hole 710, and a reflecting layer 800 having irregularities for improving reflectance is formed, and the reflecting layer 800 is formed. An edge circumference of the edge overlaps the gate line 200 and the data line 600.

R, G, and B color filters 900 are formed on the reflective film 800 in units of pixels, and the R, G, and B color filters 900 may include a gate electrode 210, a semiconductor layer 400, and a source / The drain electrodes 610 and 620 are covered. At this time, in order to uniformly form the alignment of the liquid crystal molecules, the R, G, and B color filters 900 are planarized.

Meanwhile, a common electrode 170 is formed on the entire surface of the second substrate 110 in the second insulating substrate 110 facing the first insulating substrate 100.

When the protective film 700 is formed of a black matrix material as described above, the protective film 700 not covered by the color filter 900 becomes hatched in FIG. 2 to function as a black matrix. At this time, the portion where the image is displayed becomes the entire reflective film 800 so that the aperture ratio and the reflectance become maximum.

In addition, since the passivation layer 700 made of a black matrix material blocks light incident on the semiconductor layer 400 of the thin film transistor, no light leakage current is generated in the thin film transistor.

In addition, since the R, G, and B color filters 900 are directly formed on the reflective film 800, mutual interference of R, G, and B rarely occurs even when light is incident and reflected obliquely. Thus, color purity and contrast ratio are improved.

Next, a method of manufacturing a thin film transistor substrate for a reflective liquid crystal display device according to an exemplary embodiment of the present invention will be described in detail. Here, since the manufacturing method of the color filter substrate is simple, the description thereof will be omitted.

4 and 5 are views illustrating a method of manufacturing a thin film transistor substrate for a reflective liquid crystal display according to an exemplary embodiment of the present invention according to a process sequence, and FIG. 5 is a cross-sectional view taken along the line VV in FIG. 4. .

4 and 5, the gate patterns 200 and 210 and the storage electrode line 220 are formed by depositing and patterning a conductive material of a low resistance metal such as aluminum on the insulating substrate 100. Next, silicon nitride or the like is deposited thereon to form a gate insulating film 300, and amorphous silicon and doped amorphous silicon are sequentially deposited and then patterned together to form a semiconductor layer 400 of the thin film transistor. Depositing and patterning conductive materials such as chromium, aluminum alloys, molybdenum, molybdenum alloys, etc. to form data patterns 600, 610, 620, connections 630 and sustain electrodes 640, and etching the exposed doped amorphous silicon layer. To form the ohmic contacts 510 and 520. Next, a protective film 700 is formed by stacking a black matrix material having a property of absorbing light and having a high resistance, and forming a contact hole 710 exposing the drain electrode 620 by patterning the protective film 700. .

At this time, when the insulating property of the black matrix material of the protective film 700 is low, as described above, an insulating film made of silicon nitride or silicon oxide may be added to form the protective film 700 in multiple layers.

The protective film 700 may be formed by stacking silicon nitride, silicon oxide, or an organic insulating film having excellent planarization.

Subsequently, as shown in FIGS. 2 and 3, a metal material having a high reflectance is stacked and patterned on the substrate 100 to be connected to the drain electrode 620 through the contact hole 710 to have an uneven surface. 800). In this case, an edge circumference of the reflective film 800 overlaps the gate line 200 and the data line 600. Next, an R, G, and B photosensitive resist is stacked and patterned on the substrate 100 to form a planarized R, G, and B color filter 900.

As described above, the thin film transistor substrate 100 and the common electrode 170 are combined with the color filter substrate 110, and a liquid crystal material is injected between the two substrates 100 and 110. A liquid crystal display device can be completed.

In the method of manufacturing the liquid crystal display according to the present invention, the planarization film 9 (refer to FIG. 1) is formed by forming the planarized R, G, and B color filters 900 on the lower substrate 100, unlike the prior art. The process may be omitted, and the process of forming the black matrix separately may be omitted by forming the black matrix with the protective film 700, thereby simplifying the manufacturing process. In addition, since the black matrix 700, the color filter 900, and the reflective film 800 are formed on one substrate 100, there is no need to consider misalignment, thereby improving the aperture ratio.

In the above-described method of manufacturing a thin film transistor substrate for a reflective liquid crystal display device, the R, G, and B color filters 900 are formed so as to be separated from the upper portion of the gate line 200 and the data line 600 by pixel. In consideration of this, the R, G, and B color filters 900 may be formed to be in contact with each other on the gate line 200 and the data line 600. In addition, when the protective film 700 is not formed of a black matrix material but an organic insulating film, a black matrix may be further formed between the R, G, and B color filters 900.

Therefore, in the reflective liquid crystal display device and the manufacturing method thereof according to the present invention, the contrast ratio, the reflectance and the aperture ratio can be improved, and the reliability of the product can be improved by blocking the light leakage current of the thin film transistor. In addition, manufacturing costs can be reduced by simplifying the manufacturing process.

Claims (7)

Insulation board, A gate pattern including a gate line formed on the substrate and a gate electrode connected to the gate line; A gate insulating film covering the gate pattern, A semiconductor layer formed on the gate insulating film of the gate electrode; A data line formed on the gate insulating layer and defining a pixel region crossing the gate line, and a source electrode formed on the semiconductor layer and connected to the data line and a drain facing the source electrode with respect to the gate electrode; A data pattern comprising electrodes, A passivation layer covering the gate pattern and the data pattern and having a contact hole exposing the drain electrode; A reflective film formed in the pixel region above the passivation film and connected to the drain electrode through the contact hole; R, G, B color filters formed on the reflective film of the pixel region and planarized Thin film transistor substrate for a reflective liquid crystal display comprising a. In claim 1, The protective layer is a thin film transistor substrate for a reflective liquid crystal display device made of silicon nitride, silicon oxide, a storage insulating film or a material for a black matrix. In claim 1, And a common electrode line formed on the substrate and overlapping the reflective layer across the pixel region. In claim 3, And a common electrode insulated from and overlapping with the common electrode line through the gate insulating layer, and connected to the drain electrode through a connection part. In claim 4, A thin film transistor substrate for a reflective liquid crystal display device, wherein a circumference of the reflective film overlaps the gate line and the data line. A gate pattern including a gate line and a gate electrode, a gate insulating layer covering the gate pattern, a semiconductor layer on the gate insulating layer corresponding to the gate electrode, a data line and a semiconductor to be insulated from and cross the gate line to define a pixel region Stacking a protective film on a substrate having a data pattern including a source electrode and a drain electrode connected to the layer; Patterning the passivation layer to form a contact hole exposing a portion of the drain electrode; Stacking and patterning a conductive material having a reflectance on the passivation layer to form a reflecting layer, Applying and patterning R, G, and B photosensitive resists on the substrate to form R, G, and B color filters, Method of manufacturing a thin film transistor substrate for a reflective liquid crystal display device comprising a. In claim 6, And the protective film is formed of silicon nitride, silicon oxide, a storage insulating film, or a material for a black matrix.