KR100806890B1 - Thin film transistor and fabricating method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor and a method of manufacturing the same, in order to simplify the manufacturing process, a color filter is formed using an electrodeposition technique using a pixel electrode. In the thin film transistor substrate according to the present invention, a gate line is formed on the substrate, and a data line is formed to cross the gate line insulated so as to define a pixel region. In the pixel region, a thin film transistor electrically connected to the gate line and the data line and a pixel electrode connected to the thin film transistor are formed, and a color filter is electrodeposited on the pixel electrode. In order to manufacture such a thin film transistor substrate, after forming a pixel electrode connected to the drain electrode of the thin film transistor, a color filter is formed on the pixel electrode by using an electrodeposition technique.

Simplify manufacturing processes, electrodeposition technology, color filters

Description

Thin film transistor substrate and its manufacturing method {THIN FILM TRANSISTOR AND FABRICATING METHOD THEREOF}

1 is a layout view of a thin film transistor substrate according to an embodiment of the present invention,

FIG. 2 is a cross-sectional view of the substrate shown in FIG. 1 along a cutting line II-II '; FIG.

3A is a layout view of a substrate in a first manufacturing step for manufacturing a thin film transistor substrate according to an embodiment of the present invention;

3B is a cross-sectional view of the substrate shown in FIG. 3A along a cutting line IIIb-IIIb ',

4A is a layout view of a substrate in the next manufacturing step of FIG. 3A,

4B is a cross-sectional view of the substrate shown in FIG. 4A along a cutting line IVb-IVb '.

FIG. 5A is a layout view of a substrate in a subsequent manufacturing step of FIG. 4A,

FIG. 5B is a cross-sectional view of the substrate shown in FIG. 5A along a cutting line Vb-Vb ′,

FIG. 6A is a layout view of a substrate in a subsequent manufacturing step of FIG. 5A;

FIG. 6B is a cross-sectional view of the substrate shown in FIG. 6A along a cutting line VIb-VIb ′.

FIG. 7A is a layout view of a substrate in a subsequent manufacturing step of FIG. 6A,

FIG. 7B is a cross-sectional view of the substrate shown in FIG. 7A along a cutting line VIIb-VIIb ',

FIG. 8A is a layout view of a substrate in a subsequent manufacturing step of FIG. 7A, and FIG.

FIG. 8B is a cross-sectional view of the substrate shown in FIG. 8A along a cutting line VIIb-VIIb ',                 

9 is a cross-sectional view of the substrate at a subsequent stage of manufacture of FIG. 8B.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor substrate and a method for manufacturing the same, and more particularly, to a thin film transistor substrate for use in a liquid crystal display device and a manufacturing method thereof.

A liquid crystal display device, which is one of the widely used flat panel display devices, is composed of two substrates on which electrodes are formed and a liquid crystal layer interposed therebetween. By displaying, the image is displayed in such a manner as to adjust the amount of light transmitted through the liquid crystal layer.

A typical liquid crystal display device includes a thin film transistor substrate on which a plurality of wirings such as gate lines and data lines, pixel electrodes, and thin film transistors are formed, and a common electrode, red (R), and green (G) facing the pixel electrodes of the thin film transistor substrate. ) And a color filter substrate on which a blue (B) color filter is formed.

Each wire and elements of the liquid crystal display device are manufactured through a photolithography process using a mask, as in a conventional semiconductor manufacturing process. In the photolithography process, five or six masks are typically used for a thin film transistor substrate, and three or four masks are used for a color filter substrate.

The photolithography process is performed through a series of complicated processes such as a process of manufacturing a mask having a predetermined pattern, a photo process of forming a photoresist pattern, and an etching process of etching a lower layer with the photoresist pattern using an etching mask. Therefore, simplifying the manufacturing process by reducing the number of masks used in the photolithography process is required in that it reduces the production cost of the liquid crystal display and improves the production yield.

It is an object of the present invention to provide a thin film transistor substrate and a method of manufacturing the same, which can simplify the manufacturing process.

In order to solve this technical problem, the present invention forms a color filter using an electrodeposition technique using a pixel electrode.

In detail, in the thin film transistor substrate according to the present invention, a gate line is formed on the substrate, and a data line defining an area of the pixel by crossing the gate line insulated from each other is formed. In the pixel region, a thin film transistor electrically connected to the gate line and the data line and a pixel electrode connected to the thin film transistor are formed, and a color filter is electrodeposited on the pixel electrode.

The pixel electrode may be formed in a double layer structure in which a reflective electrode having a transmission window and a transparent electrode are stacked. The pixel electrode may further include a black matrix formed in a region between the pixel electrodes.

In addition, to manufacture a thin film transistor substrate according to the present invention, first, a data line defining an area of a pixel by crossing the gate line and the gate line to be insulated from the substrate, and electrically connected to the gate line and the data line in the pixel area. Form a thin film transistor. Subsequently, after forming a protective film covering the substrate including the thin film transistor, a contact hole for exposing the drain electrode of the thin film transistor is formed in the protective film. Subsequently, after forming the pixel electrode connected to the drain electrode through the contact hole, a color filter is formed on the pixel electrode by using an electrodeposition technique.

Here, the electrodeposition technique may be performed by applying a gate-on voltage to the gate line and then applying an electrodeposition voltage to the pixel electrode through the data line.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

1 is a layout view of a thin film transistor substrate according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view of the thin film transistor substrate taken along the cutting line II-II ′ of FIG. 1.

The gate line 22 and the gate line 22 which are formed at one end of the gate line 22 and the gate line 22 extending in the horizontal direction on the insulating substrate 10 to transfer the scanning signal to the gate line 22. Gate wirings 22, 24, and 26 are formed including the gate electrode 26 protruding from the top.

The gate wirings 22, 24, and 26 are advantageously formed of a low resistance metal material in order to be applied to a large area liquid crystal display device. In addition, the gate wirings 22, 24, and 26 may be formed in a single layer structure, or may be formed in a double layer structure or more. In the case of the single layer structure, the chromium or chromium alloy, molybdenum or molybdenum alloy, aluminum or aluminum alloy may be formed. Silver or a silver alloy is used, and when formed in a double layer structure, at least one of the two layers is preferably formed of a low resistance metal material.

The gate insulating film 30 made of silicon nitride or the like covers the gate wirings 22, 24, 26, 27, and 29 on the insulating substrate 10.

A semiconductor pattern 42 made of a semiconductor such as amorphous silicon is formed on the gate insulating layer 30, and an amorphous silicon or the like doped with a high concentration of impurities is formed on the semiconductor pattern 42. Resistive contact patterns 55 and 56 are formed, respectively.

On the gate insulating layer 30, the data line 62 and the data line 62 defining the pixel area are intersected with the gate line 22 extending in the horizontal direction, and the image signal is transmitted to the data line 62. The resistive contact layer 56 corresponding to the source electrode 65 and the source electrode 65 extending from the data pad 64, the data line 62, and in contact with the resistive contact layer 55. Data wirings 62, 64, 65, and 66 are formed including the drain electrodes 66 in contact with each other.

The data lines 62, 64, 65, and 66 are advantageously formed of a low resistance metal material in order to be applied to a large area liquid crystal display. In addition, the data lines 62, 64, 65, and 66 may also be formed in a single layer structure or in a double layer structure or the same as the gate lines 22, 24, and 26. Chromium or chromium alloys, molybdenum or molybdenum alloys, aluminum or aluminum alloys, or silver or silver alloys are used, and when formed in a double layer structure, at least one of the two layers is preferably formed of a low resistance metal material.

Here, the gate electrode 26, the semiconductor pattern 42, the source electrode 65, and the drain electrode 66 constitute a thin film transistor TFT.                     

A passivation layer 70 formed of an organic material on the data lines 62, 64, 65, and 66 and a thin film transistor TFT is patterned to have an uneven shape.

In the passivation layer 70, first and second contact holes 72 and 74 exposing the drain electrode 66 and the data pad 64, respectively, are formed, and the gate pad 24 is exposed together with the gate insulating layer 30. The third contact hole 76 is formed.

The protective electrode 70 is connected to the drain electrode 66 through the first contact hole 72, and includes a reflective electrode 80 made of a metal material having excellent reflective properties such as aluminum or an aluminum alloy, and a transparent conductive material such as ITO or IZO. A double layer pixel electrode P formed by stacking transparent electrodes 90 made of a material is formed. In this case, the reflective electrode 80 is positioned below the double layer structure, and is patterned to have a transmission window H under the pixel area, and the transparent electrode 90 is positioned above the double layer structure, but the pixel area Since the total area of the cell is autonomous, the transflective pixel electrode P is realized. In this case, the pixel electrode P may have a concave-convex shape in accordance with the concave-convex shape of the surface of the protective film 70, thereby improving the reflection efficiency of the reflective electrode 80.

In addition, the passivation layer 70 covers the data pad 64 and the gate pad 24 through the second and third contact holes 74 and 76, and the auxiliary gate pad and the auxiliary data pad 94 made of a transparent conductive material. 96) is formed.

The color filter 100 having one of red, green, and blue colors is formed on the transparent electrode 90 of the pixel electrode P, and that is, the data line 62 and the gate in the region between the pixel electrodes P. The black matrix BM which consists of organic black fats and oils which overlaps the line 22 is formed.

As such, since the black matrix BM is formed on the thin film transistor substrate, it is not necessary to consider the alignment margin caused in the process of bonding the color filter substrate and the thin film transistor substrate during the manufacturing process of the liquid crystal display device, thereby increasing the aperture ratio. have.

The organic passivation layer 110 covers the pixel electrode P and the black matrix BM.

In the thin film transistor substrate according to the embodiment of the present invention described above, if the organic protective film 70 is formed flat and the pixel electrode P is composed of only the transparent electrode 90, the substrate employed in a typical transmissive liquid crystal display device. Becomes

In addition, if the pixel electrode P consists only of the reflective electrode 80 which does not have the transmission window H, it becomes a board | substrate employ | adopted in the normal reflective liquid crystal display device. In this case, the auxiliary data and the gate pads 94. 96 may be formed of a material for forming the reflective electrode 80.

Next, a method of manufacturing the liquid crystal display according to the exemplary embodiment of the present invention will be described in detail with reference to FIGS. 3A to 9 and FIGS. 1 and 2.

First, as shown in FIGS. 3A and 3B, a metal layer made of aluminum or an aluminum alloy, chromium or chromium alloy, molybdenum or molybdenum alloy, titanium or titanium alloy, or tantalum or tantalum alloy is deposited on the insulating substrate 10. The metal layer is patterned by a photolithography process to form gate wirings 22, 24, and 26 including the gate lines 22, the gate pads 24, and the gate electrodes 26.

Next, as illustrated in FIGS. 4A and 4B, after the three-layer films of the gate insulating film 30, the semiconductor layer, and the semiconductor layer doped with impurities are sequentially stacked, the semiconductor layer and the semiconductor layer doped with impurities are subjected to a photolithography process. Patterning is performed to form the ohmic contact layer pattern 52 and the semiconductor pattern 42 corresponding to the gate electrode 26.

Next, as shown in FIGS. 5A and 5B, a metal layer made of chromium or chromium alloy, molybdenum or molybdenum alloy, titanium or titanium alloy, tantalum or tantalum alloy is deposited on the gate insulating layer 30 and the semiconductor pattern 42. Subsequently, the metal layer is patterned by a photolithography process to form the data lines 62, 64, 65, and 66 including the data line 62, the data pad 64, the source electrode 65, and the drain electrode 66. Form.

Subsequently, the ohmic contact layer pattern 52 is etched using the data wiring as a mask to separate the ohmic contact layer 55 contacting the source electrode 65 and the ohmic contact layer 56 contacting the drain electrode 65. .

Next, as shown in FIGS. 6A and 6B, an organic film made of an acrylic organic material such as bisbenzocyclobutene (BCB) or perfluorocyclobutene (PFCB) is coated, and then the drain electrode 66 is formed by patterning the organic film by a photolithography process. A first contact hole 72 that exposes, a second contact hole 74 that exposes the data pad 64, and a hole that exposes a portion of the gate insulating film 30 on the gate pad 24, and the upper portion is patterned into an uneven shape. An organic protective film 70 is formed.

Subsequently, a portion of the gate insulating layer 30 on the gate pad 24 is etched using the organic protective layer 70 as a mask, and the third contact hole 76 exposing the gate pad 24 is exposed to the organic protective layer 70 and the gate. It is formed in the insulating film 30.

In order to form the organic passivation layer 70 as described above, two exposure processes are successively performed on the applied organic film, and the first contact hole 72, the gate pad 24, and the data pad are subjected to the first exposure process. Selective exposure to define a second light third contact hole 74, 76 exposing 64, and an organic film subjected to conventional embossing exposure that causes the top of the organic film to be patterned into an uneven shape through the second exposure process. Proceed to the whole. Thereafter, as described above, when the organic film that has undergone two exposure processes is developed, an organic protective film 70 having a pattern as shown in the drawing may be formed.

Next, as shown in FIGS. 7A and 7B, a metal material having excellent reflection characteristics, for example, aluminum or an aluminum alloy is deposited on the resulting substrate on which the organic protective film 70 is formed, and then photo-etched to form a first contact hole. A reflective electrode 80 having a transmission window H is connected to the drain electrode 66 through the pixel electrode 72.

Subsequently, a transparent conductive material such as ITO or IZO is deposited on the reflective electrode 80 and the organic passivation layer 70, and then photo-etched to form the transparent electrode 90. At this time, the auxiliary data pads and the auxiliary gate pads 94 and 96 which are connected to the data pads and the gate pads 64 and 24 through the second and third contact holes 74 and 76 are formed together.

In the embodiment of the present invention, the transparent electrode 90 forms a pixel electrode P having a double layer structure together with the reflective electrode 80 contacting the lower portion thereof.

In this case, the reflective electrode 80 may be formed without the transmission window H, and the transparent electrode 90 may not be formed, thereby forming the pixel electrode P using only the reflective electrode 80. In this case, the auxiliary data and the gate pads 94. 96 are formed of a material for forming the reflective electrode 80.                     

In addition, by forming only the transparent electrode 90 without forming the reflective electrode 80, the pixel electrode P can be formed only by the transparent electrode 90.

Subsequently, as shown in FIGS. 8A and 8B, after the black organic material is coated on the entire surface of the substrate, the black matrix BM overlapping the gate line 22 and the data line 62 is selectively exposed and developed. Form. At this time, the black matrix BM functions as a spacer when forming a predetermined height or more in addition to a light blocking function of preventing light from being reflected from the gate line 22 and the data line 62.

Next, as illustrated in FIG. 9, the color filters 100 of red (R), green (G), and blue (B) are sequentially formed for each pixel cell on the transparent electrode 90 by the electrodeposition process.

The electrodeposition process uses a technique of depositing a conductive layer on a substrate and then patterning to form an electrically colored layer on the conductive film. Specifically, a color filter is formed by forming a colored layer having a predetermined thickness on the electrode plate for electrodeposition by applying a voltage between the electrode plate for electrodeposition and the counter electrode in the electrodeposition solution in which the pigment is dispersed in a charge-soluble resin.

In the present invention, after the substrate on which the transparent electrode 90, which is called electrode plate for electrodeposition, is formed is immersed in a solution in which pigments, surfactants, conductive polymers and the like are dispersed and mixed, the transparent electrode 90 is used as an anode, and the transparent electrode Using a counter electrode (not shown) opposite to 90 as the cathode, one of three pigments of red, green, and blue, for example, a red pigment, is colored onto the transparent electrode 90 to produce a red Create a color filter. Subsequently, green and blue color filters are sequentially produced by coloring the green and blue pigments on the other transparent electrodes in a similar manner.

At this time, the black matrix BM is formed in the region between the transparent electrodes 90, and functions as a prevention film which prevents the pigment from coloring in regions other than the transparent electrode 90 during the electrodeposition process.

In the present invention, a gate wiring and a data wiring are used to apply a predetermined voltage to the transparent electrode 90. That is, all the thin film transistors are turned on by applying a gate-on voltage to all the gate lines 22 on the substrate through the gate pads 24, and then the pixel cells to which the color filters are to be formed have a specific color. The electrodeposition voltage is applied to the data line 62 through the data pad 64. The electrodeposition voltage is applied to the reflective electrode 80 and the transparent electrode 90 of the pixel electrode P after passing through the data line 62, the source electrode 65, and the drain electrode 66. At the same time, another voltage is applied to the counter electrode (not shown) to produce a color filter by coloring the pigment of the electrodeposition solution to a predetermined thickness on the transparent electrode 90 by the voltage difference between the transparent electrode and the counter electrode in the electrodeposition solution.

Such a color filter manufacturing step is required to color the pigment on the transparent electrode by an electrodeposition technique, so that after applying the organic film for color filters, selective exposure and development using a mask to produce a color filter, the process For simplicity, it is advantageous.

Subsequently, a thin film of the organic layer 110 supporting the pigment of the color filter 100 formed on the transparent electrode 90 is manufactured to manufacture a thin film transistor substrate having a cross-sectional structure as shown in FIG. 2.

As described above, in the present invention, the color filter is formed by the electrodeposition technique using the pixel electrode without forming a separate pattern or performing an additional process, thereby simplifying the manufacturing process.

Claims (7)

Board; A gate line formed on the substrate; A data line insulated from and intersecting the gate line to define a pixel area; A thin film transistor electrically connected to the gate line and the data line in the pixel area; An organic insulating layer formed on the thin film transistor; A pixel electrode formed on the organic insulating layer and connected to the thin film transistor and including a reflective electrode having a transmission window and a transparent electrode formed on the reflective electrode; And A color filter electrodeposited on the pixel electrode Containing Transflective thin film transistor substrate. delete In claim 1, A semi-transmissive thin film transistor substrate further comprising a black matrix formed in the region between the pixel electrode. Forming a thin film transistor electrically connected to the gate line and the data line in the pixel region, the data line defining a pixel region by crossing the gate line and the gate line insulated from each other; Forming an organic insulating layer covering the substrate including the thin film transistor; Forming a contact hole in the organic insulating layer to expose a drain electrode of the thin film transistor; Forming a reflective electrode having a transmission window on the organic insulating layer; Forming a transparent electrode on the reflective electrode; And Forming a color filter on the transparent electrode using an electrodeposition technique Containing Method for manufacturing a transflective thin film transistor substrate. In claim 4, The electrodeposition technique is a method of manufacturing a transflective thin film transistor substrate by applying a gate-on voltage to the gate line, and then applying an electrodeposition voltage to the pixel electrode through the data line. In claim 1, The organic insulating layer is a semi-transmissive thin film transistor substrate having a concave-convex surface. In claim 4, And forming a contact hole in the organic insulating film to pattern the surface of the organic insulating film into an uneven shape.

Images