KR100552292B1 - Reflective Liquid Crystal Display and Manufacturing Method Thereof - Google Patents

Abstract

A gate wiring made of a gate line and a gate electrode which is a branch of the gate line is formed on the insulating substrate in a horizontal direction, and a storage electrode line parallel to the gate line is formed. On the gate insulating film covering the gate wiring and the storage electrode line, a data wiring 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 region 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 black matrix made of a material having high resistivity and a high resistance is formed on the data line and the gate insulating layer, and a contact hole exposing the drain electrode is formed in the black matrix. Finally, a reflective film is formed in the upper pixel region of the black matrix, which is connected to the drain electrode through the contact hole, and the edge of which overlaps the gate line and the data line. 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.

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 having transparent electrodes formed thereon, a liquid crystal material between two glass substrates, and two polarizing plates attached to an outer surface of each glass substrate to polarize light. It can be divided into a transmissive type having a back light emitting light and a reflective type using natural light.

The conventional reflective liquid crystal display device includes a first substrate in which a thin film transistor and a reflection film are formed in each pixel, a black matrix covering portions other than the reflection film, and a second substrate in which a color filter is formed in the pixel.

In such a reflective liquid crystal display device, light is incident on the outer surface of the second substrate and passes through the color filter and the liquid crystal layer, and the incident light is reflected by the reflective film of the first substrate and is again the color filter of the liquid crystal layer and the upper substrate. Display an image by passing through it.

However, such a conventional reflective liquid crystal display device has a reduced contrast ratio due to light reflected directly by the black matrix and light incident by the reflective film after being incident obliquely to the substrate and then reflected by the black matrix and the reflective film again. I have a problem. In addition, the aperture ratio and the reflectance of the pixel are reduced because the black matrix is widely formed so that they are superimposed with each other in consideration of misalignment of the reflective film and the black matrix. Light leakage current is generated in the amorphous silicon layer of the thin film transistor due to the light incident obliquely to the substrate, thereby causing a problem of deterioration of device characteristics.

An object of the present invention is to improve the 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 the reflective liquid crystal display according to the present invention for achieving the above object, a black matrix is formed on a thin film transistor substrate.

At this time, the black matrix is formed between the gate line and the data line and the reflective film, and the edge of the reflective film overlaps the gate line and the data line.

More specifically, a gate wiring formed of a gate line and a gate electrode which is a branch of the gate line is formed on a substrate, and a gate insulating film covering the gate wiring is formed. A data line is formed on the gate insulating layer, the data line including a data line defining a pixel region crossing the gate line, a source electrode that is a branch of the data line, and a drain electrode that faces the source electrode around the gate electrode. A black matrix having a contact hole covering the data line and exposing the drain electrode is formed. The pixel region on the black matrix is connected to the drain electrode through a contact hole, and a reflective film overlapping the gate line and the data line is formed around the edge.

In the method of manufacturing a thin film transistor substrate for a reflective liquid crystal display device according to the present invention, a black matrix is formed only on the gate line and the data line, or a method is formed on the entire upper surface of the substrate.

First, when formed on the upper front surface of the substrate, a gate wiring including a gate line and a gate electrode, a semiconductor layer of a portion corresponding to the gate electrode, a gate insulating layer between the semiconductor layer and the gate wiring, and the gate line A black matrix is stacked and patterned on a substrate on which a data line including an insulated and crossing data line defining a pixel region and a source / drain electrode connected to the semiconductor layer is formed, thereby forming a contact hole exposing a portion of the drain electrode. . Next, a conductive material having a reflectance is stacked and patterned on the black matrix to form a reflective film connected to the drain electrode.

Again, there are two methods for forming only on the gate line and the data line.

First, the gate wiring and the first black including the gate line and the gate electrode by sequentially stacking the first conductive material and the first black matrix material on the substrate and patterning the first conductive material and the first black matrix material together. To form a matrix. Next, a gate insulating film is stacked on the substrate, and an undoped amorphous silicon layer and a doped amorphous silicon layer are formed on the gate insulating film. Subsequently, the second conductive material and the second black matrix material are sequentially stacked on the substrate, and the second conductive material and the second black matrix material are patterned together to form a data line including a data line and a source / drain electrode. 2 form a black matrix. Next, a protective film is laminated and the protective film is patterned together with the second black matrix so that a part of the drain electrode is exposed. Finally, a third conductive material having a reflectance is stacked and etched to form a reflective film connected to the drain electrode.

Second, the first conductive material is stacked and patterned on the substrate to form a gate wiring including a gate line and a gate electrode, and a gate insulating film is formed on the substrate. An undoped amorphous silicon layer and a doped amorphous silicon layer are formed on the gate insulating layer, the second conductive material and the black matrix material are sequentially stacked on the substrate, and the second conductive material and the black matrix material are patterned together. A black matrix is formed on the data line and the gate line including the data line and the source / drain electrodes.

In the reflective liquid crystal display and the manufacturing method thereof according to the present invention, the black matrix is preferably formed of an organic film including a chromium oxide film or a black dye, and is insulated from and overlapped with the common electrode line and the common electrode line passing through the pixel area on the substrate. It is also possible to add a common electrode.

DETAILED DESCRIPTION OF THE EMBODIMENTS 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 can easily perform the embodiments.

Unlike the prior art, in the exemplary embodiment of the present invention, a black matrix is formed on the thin film transistor substrate for the liquid crystal display device and the manufacturing method thereof. In this case, the black matrix is formed between the gate wiring and the data wiring and the reflective film, and the edge of the reflective film overlaps the gate line and the data line. The black matrix may be formed as a passivation layer covering the gate line and the data line, or may be formed together when forming the data line or the gate line.

First, the structure and method formed from the protective film will be described in detail.

1 is a layout view illustrating a structure of a thin film transistor substrate for a reflective liquid crystal display device according to a first exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along line II-II of FIG. Shown in addition.

1 and 2, in the reflective liquid crystal display according to the first exemplary embodiment of the present invention, a gate line 200 and a gate line transferring scan signals in a horizontal direction on the first insulating substrate 100 are provided. A gate wiring made of the gate electrode 210 which is a branch of the 200 is formed, and the storage electrode line 220 constituting one electrode of the storage capacitor is formed in parallel with the gate line 200.

The gate insulating layer 300 made of silicon nitride or the like is covered on the gate wires 200 and 210 and the storage electrode line 220. The semiconductor layer 400 of the thin film transistor made of amorphous silicon or the like is formed on the gate insulating layer 300 on the gate electrode 210. 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 to form a storage capacitor together with the storage electrode line 220, and the storage electrode 640 is connected to the drain electrode through the connection portion 630. 620 is connected.

The light blocking property is excellent on the data lines 600, 610, and 620, the connection part 630, the storage electrode 640, the semiconductor layer 400, and the gate insulating layer 300, and has a high resistance to chromium oxide or black. A black matrix 700 made of an organic layer including a dye is formed over the entire surface, and a contact hole 710 exposing the drain electrode 620 is formed in the black matrix 700. In this case, when the insulation of the black matrix 700 is low, an insulating film made of silicon nitride or silicon oxide may be added to the upper and / or lower portions of the black matrix 700. In addition, when the flatness of the black matrix 700 is not good, an organic insulating layer having excellent planarization may be added on the black matrix 700.

In the upper pixel area P of the black matrix 700, a reflective film 800 made of a conductive material such as aluminum or aluminum-neodymium alloy having high reflectivity is connected to the drain electrode 620 through a contact hole 710. Formed. Here, the edge circumference of the reflective film 800 overlaps the gate line 200 and the data line 600, but may not be.

Meanwhile, R, G, and B color filters 130 are formed in the unit pixel, respectively, on the second insulating substrate 110 facing the first insulating substrate 100, and the common electrode 140 is disposed on the color filter 130. ) Is formed over the entire surface.

In the thin film transistor substrate for the reflective liquid crystal display device, the black matrix 700 exposed without being covered by the reflective film 800 is hatched in FIG. 1. Therefore, since the portion where the image is displayed is the entire reflective film 800, the aperture ratio and the reflectance become maximum. In addition, since the black matrix 700 covers the semiconductor layer 400 of the thin film transistor and blocks incident light, light leakage current does not occur.

Next, a method of manufacturing the thin film transistor substrate for a reflective liquid crystal display device according to the first embodiment of the present invention will be described in detail.

3 is a layout view illustrating a manufacturing process of a thin film transistor substrate for a reflective liquid crystal display device according to a first exemplary embodiment of the present invention, and FIG. 4 is a cross-sectional view taken along the line V-V of FIG. 3.

3 and 4, the gate wirings 200 and 210 and the storage electrode line 220 are formed by depositing and patterning a conductive material such as 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 then the amorphous silicon layer 400 and the doped amorphous silicon layer are sequentially deposited and then patterned together. After depositing a conductive material such as chromium, an aluminum alloy, molybdenum, molybdenum alloy, and the like, and forming a photoresist pattern, the pattern is patterned with a mask to form the data wirings 600, 610, and 620, the connection part 630, and the sustain electrode 640. Subsequently, the exposed doped amorphous silicon layer is etched to form the ohmic contacts 510 and 520.

Next, as shown in FIGS. 1 and 2, the black matrix 700 having a contact hole 710 exposing the drain electrode 620 by stacking and patterning a material for high-resistance black matrix having a light absorbing property. ). Here, when the black matrix 700 has low insulation, it is preferable to add a step of forming an insulating film made of silicon nitride or silicon oxide as described above. In addition, when the planarization of the black matrix 700 is not good, it is preferable to further form a planarization film on the black matrix 700. Subsequently, a metal material having a high reflectance is stacked and patterned to form a reflective film 800 connected to the drain electrode 620 through the contact hole 710. In this case, an edge circumference of the reflective film 800 overlaps the gate line 200 and the data line 600.

As long as the thin film transistor substrate, the color filter 130, and the common electrode 140 are formed, the liquid crystal material may be combined with the color filter substrate and the liquid crystal material may be injected to complete the liquid crystal display according to the first exemplary embodiment. .

In the manufacturing method of the liquid crystal display according to the present invention, it is not necessary to consider the misalignment by forming the black matrix 700 and the reflective film 800 on one substrate 100, and the process of forming the black mattress on the color filter substrate is omitted. By doing so, the manufacturing process can be simplified.

Next, a structure and method in which a black matrix is further formed on the data line and the gate line will be described in detail.

FIG. 5 is a layout view illustrating a structure of a thin film transistor substrate for a reflective liquid crystal display according to a second exemplary embodiment of the present invention, and FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 5.

As shown in FIGS. 5 and 6, the reflective liquid crystal display according to the second exemplary embodiment of the present invention is similar to the first exemplary embodiment in that the gate wirings 200 and 210 are disposed on the insulating substrate 100 in the horizontal direction. The storage electrode line 220 parallel to the gate line 200 is formed. The semiconductor layer 400, the resistance contact layers 510 and 520, the source electrode 610, and the drain are disposed on the gate insulating layer 300 of the gate electrode 210 covering the gate wirings 200 and 210 and the storage electrode line 220. The electrodes 620 are formed in sequence. In addition, the gate electrode 300 is connected to the source electrode 610 and intersects with the gate line 200 to define a drain electrode through the data line 600 and the connection part 630 that define the unit pixel region P. A storage electrode 640 connected to the 620 and overlapping the storage electrode line 220 is formed.

However, the black matrix 150 is formed on the data lines 600, 610, and 620 along the data lines, and the dummy wires 650 are isolated on the gate insulating layer 300 on the gate lines 200. The black matrix 151 is formed in order. Although not shown in FIG. 5, a black matrix is formed on the connection part 630 and the storage electrode 640. In this case, the black matrices 150 and 151 are excellent in absorbing light and are made of an organic film including a chromium oxide film (CrO _X ), which is a material having high resistance, or a black dye.

The passivation layer 750 is formed on the black matrix 150 and the 151 and the gate insulating layer 300 not covered by the black matrix 150 and 151, and the drain electrode 620 is formed on the passivation layer 700 and the black matrix 150. The contact hole 720 is formed to expose the.

Lastly, a reflective film 800 connected to the drain electrode 620 is formed in the upper pixel area P of the passivation layer 750 through the contact hole 720. It overlaps with the 200 and the data line 600.

In the thin film transistor substrate for a reflective liquid crystal display according to the second exemplary embodiment of the present invention, the hatched portions in FIG. 5 are portions in which the black matrices 150 and 151 are not covered by the reflective film 800 and are exposed. Therefore, the aperture ratio and the reflectance become maximum. In addition, light incident between the reflective film 800 and the data lines 600, 610, and 620 is absorbed by the black matrix 700 and thus cannot enter the semiconductor layer 400.

Next, a method of manufacturing the thin film transistor substrate for a reflective liquid crystal display device according to the second embodiment of the present invention will be described in detail.

7A and 7B to 8A and 8B illustrate a method of manufacturing a thin film transistor substrate for a reflective liquid crystal display device according to a second embodiment of the present invention, in the order of their processes. 7B and 8B are cross-sectional views taken along the lines VIIb-VIIb and VIIIb-VIIIb in FIGS. 7A and 8A, respectively.

First, as shown in FIGS. 7A and 7B, similar to the first embodiment, the gate wirings 200 and 210 and the storage electrode lines 220 are formed on the insulating substrate 100, and silicon nitride or the like is deposited thereon. The gate insulating layer 300 is formed, the amorphous silicon layer and the doped amorphous silicon layer are sequentially deposited, and then patterned together to form the semiconductor layer 400 and the doped amorphous silicon layer 500 of the thin film transistor.

Next, as shown in FIGS. 8A and 8B, a black matrix material having high resistivity and high resistance, such as a conductive material and a chromium oxide film, is sequentially deposited, a photoresist pattern is formed, and these are masked. Patterned together to form data wirings 600, 610, 620, connectors 630, sustain electrodes 640, dummy wirings 650, and black matrices 150, 151, and subsequently exposed doped amorphous silicon layers ( The 500 is etched to form the ohmic contacts 510 and 520.

Here, the dummy wire 650 is separated from the data line 600 at a portion where the gate line 200 and the data line 600 cross each other, but may be formed to be connected to the data line 600.

Next, as shown in FIGS. 5 and 6, a protective film 750 is formed by stacking silicon oxide or silicon nitride on the substrate 100, and then, the protective film 750 and the black matrix 150 are etched together to drain. A contact hole 710 is formed to expose the electrode 620. Here, the reflective film 800 connected to the drain electrode 620 through the contact hole 710 is formed by stacking and patterning a metal material of aluminum or an aluminum alloy having a high reflectance on the substrate 100. In this case, an edge circumference of the reflective film 800 overlaps the gate line 200 and the data line 600.

In the method of manufacturing the liquid crystal display device according to the second embodiment of the present invention, the reflective film 800 and the black matrix 150 and 151 are formed on the same substrate 100 as in the first embodiment, and there is no need to consider misalignment. By forming the black matrices 150 and 151 together with the data lines 600, 610 and 620 on the substrate, the process of forming the black mattress may be omitted, thereby simplifying the manufacturing process.

In the second embodiment, the black matrix in the horizontal and vertical directions is formed when the data lines are formed. However, the black matrix in the horizontal direction may be formed when the data lines are formed when the gate matrix is formed. .

9 and 10 illustrate a structure of a thin film transistor substrate for a reflective liquid crystal display according to a third exemplary embodiment of the present invention. FIG. 10 is a cross-sectional view taken along the line IX-IX of FIG. 9.

Most of the structure is similar to that of the second embodiment.

However, the black matrix 151 in the horizontal direction is formed in the same shape as the gate wiring along the gate lines 200 and 210, and the black matrix 150 in the vertical direction is connected to the data lines 600, 610, and 620. 630 and the sustain electrode 640 are formed in the same shape.

The manufacturing method of the thin film transistor substrate for a liquid crystal display according to the third embodiment of the present invention is similar to the second embodiment.

However, the black matrix 151 is formed together when patterning the gate lines 200 and 210.

Accordingly, in the reflective liquid crystal display device and the manufacturing method thereof according to the present invention, the reflectance and the aperture ratio are 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.

1 is a layout view showing a structure of a thin film transistor substrate for a reflective liquid crystal display device according to a first embodiment of the present invention;

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1;

3 and 4 illustrate a method of manufacturing a thin film transistor substrate for a reflective liquid crystal display device according to a first embodiment of the present invention.

FIG. 5 is a layout view illustrating a structure of a thin film transistor substrate for a reflective liquid crystal display device according to a second exemplary embodiment of the present invention.

6 is a cross-sectional view taken along the line VI-VI in FIG. 5,

7A and 7B and 8A and 8B are views illustrating a method of manufacturing a thin film transistor substrate for a reflective liquid crystal display device according to a second embodiment of the present invention according to a process sequence thereof.

9 and 10 illustrate a structure of a thin film transistor substrate for a reflective liquid crystal display according to a third exemplary embodiment of the present invention.

Claims (26)

Insulation board, A gate wiring formed on the substrate and a gate electrode which is a branch of the gate line; A gate insulating film covering the gate wiring, A semiconductor layer formed on the gate insulating film of the gate electrode; A data line formed on the gate insulating layer, the data line including a data line crossing the gate line to define a pixel region, a source electrode which is a branch of the data line, and a drain electrode facing the source electrode with respect to the gate electrode; A black matrix disposed over the gate insulating film and the data line of the gate line, formed over the insulating substrate, and having a first contact hole in the drain electrode; A reflective film formed in the pixel region above the black matrix and connected to the drain electrode through the contact hole; Thin film transistor substrate for a reflective liquid crystal display comprising a. Insulation board, A gate wiring formed on the substrate and a gate electrode which is a branch of the gate line; A gate insulating film covering the gate wiring, A semiconductor layer formed on the gate insulating film of the gate electrode; A data line formed on the gate insulating layer, the data line including a data line crossing the gate line to define a pixel region, a source electrode which is a branch of the data line, and a drain electrode facing the source electrode with respect to the gate electrode; A black matrix formed on the gate line and having a first portion formed in the same form as the gate line and a second portion formed on the data line and formed in the same form as the data line, A reflective film formed in the pixel region above the black matrix and connected to the drain electrode through the contact hole; Thin film transistor substrate for a reflective liquid crystal display comprising a. The method of claim 1 or 2, The black matrix is a thin film transistor substrate for a reflective liquid crystal display device comprising an organic film or a chromium oxide film containing a black dye. The method of claim 1 or 2, And a common electrode line formed on the substrate and formed horizontally across the pixel region. In claim 4, 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 2, Further comprising a protective film formed between the reflective film and the black matrix, The passivation layer is a thin film transistor substrate for a reflective liquid crystal display device having a second contact hole formed along the first contact hole. In claim 6, The passivation layer is a thin film transistor substrate for a reflective liquid crystal display device made of silicon nitride or an organic insulating film. In claim 4, And a black matrix extending on the connection part and the common electrode. In claim 2, The thin film transistor substrate of claim 1, wherein the first portion of the black matrix is formed on the gate insulating layer of the gate line. In claim 9, And a dummy wiring formed between the gate insulating film on the gate line and the black matrix of the first portion. In claim 10, The thin film transistor substrate for a reflective liquid crystal display device of which the black matrix and the dummy wiring of the first portion are formed in the same shape. In claim 11, The thin film transistor substrate for a reflective liquid crystal display device of which the dummy wire and the data line are formed on the same layer and are connected to each other. The method of claim 1 or 2, A thin film transistor substrate for a reflective liquid crystal display device wherein a circumference of the gate line, the data line, and the reflective film overlap each other. A gate wiring including a gate line and a gate electrode, a semiconductor layer in a portion corresponding to the gate electrode, a gate insulating layer between the semiconductor layer and the gate wiring, a data line insulated from and crossing the gate line, and defining a pixel region; Stacking a black matrix on a substrate on which a data line including a source / drain electrode connected to the semiconductor layer is formed; Patterning the black matrix to form contact holes exposing a portion of the drain electrode, Stacking and patterning a conductive material having a reflectance on the black matrix to form a reflective film Method of manufacturing a thin film transistor substrate for a reflective liquid crystal display device comprising a. The method of claim 14, And the black matrix is formed of an organic film containing a chromium oxide film or a black dye. The method of claim 14, A method of manufacturing a thin film transistor substrate for a reflective liquid crystal display device further comprising forming a common electrode line passing through the pixel region on the substrate. The method of claim 16, A method of manufacturing a thin film transistor substrate for a reflective liquid crystal display device, the method comprising: forming a common electrode overlapping the common electrode line. The method of claim 17, The method of claim 1, wherein the common electrode and the drain electrode are connected to each other. Sequentially depositing a first conductive material and a first black matrix material on the substrate; Patterning the first conductive material and the material for the first black matrix together to form a gate wiring including a gate line and a gate electrode and a first black matrix; Stacking a gate insulating film on the substrate; Forming an undoped amorphous silicon layer and a doped amorphous silicon layer on the gate insulating layer; Sequentially stacking a second conductive material and a second black matrix material on the substrate; Patterning the second conductive material and the material for the second black matrix together to form a data line including a data line and a source / drain electrode and a second black matrix; Etching the doped amorphous silicon layer using the data line as a mask, Laminating a protective film, Patterning the passivation layer together with the second black matrix to expose a portion of the drain electrode; Stacking a third conductive material having a reflectance, and And etching the third conductive material to form a reflective film connected to the drain electrode. The method of claim 19, And the first and second black matrices are formed of an organic film containing a chromium oxide film or a black dye. The method of claim 20, A method of manufacturing a thin film transistor substrate for a reflective liquid crystal display device further comprising forming a common electrode line passing through the pixel region on the substrate. The method of claim 21, A method of manufacturing a thin film transistor substrate for a reflective liquid crystal display device, the method comprising: forming a common electrode overlapping the common electrode line. The method of claim 22, The method of claim 1, wherein the common electrode and the drain electrode are connected to each other. Stacking and patterning a first conductive material on a substrate to form a gate wiring including a gate line and a gate electrode, Stacking a gate insulating film on the substrate; Forming an undoped amorphous silicon layer and a doped amorphous silicon layer on the gate insulating layer; Sequentially stacking a second conductive material and a black matrix material on the substrate; Patterning the second conductive material and the black matrix material together to form a data matrix including a data line and a source / drain electrode, and forming a black matrix on the data line and the gate line; Etching the doped amorphous silicon layer using the data line as a mask, Laminating a protective film, Patterning the passivation layer together with the black matrix to expose a portion of the drain electrode; Stacking a third conductive material having a reflectance, and And etching the third conductive material to form a reflective film connected to the drain electrode. The method of claim 24, And forming a dummy wiring under the black matrix above the gate line. The method of claim 25, And a dummy wiring line and a data line line are connected to each other.