KR101257733B1 - Method of fabricating the array substrate for liquid crystal display device using liquid type organic semiconductor material - Google Patents

Abstract

The present invention includes forming source and drain electrodes spaced apart from each other with data lines on a substrate; Forming a pixel electrode on the substrate in contact with the drain electrode; Forming an organic semiconductor material layer by coating a liquid organic semiconductor material on the entire surface of the substrate over the pixel electrode; Exposing a surface corresponding to the substrate edge by removing the edge of the organic semiconductor material layer; Coating an organic insulating material on the entire surface of the organic semiconductor material layer to completely cover the top and side surfaces of the organic semiconductor material layer to form an organic insulating material layer; Forming a gate electrode over the organic insulating material layer; Forming a gate insulating film and an organic semiconductor layer by removing the organic insulating material layer and an organic semiconductor material layer below the organic insulating material layer exposed outside the gate electrode; It provides a method of manufacturing an array substrate for a liquid crystal display device comprising the step of forming a gate wiring in contact with the gate electrode.

Description

Method of fabricating the array substrate for liquid crystal display device using liquid type organic semiconductor material}

1 is an exploded perspective view of a general liquid crystal display device.

2 is a cross-sectional view of a manufacturing process of an array substrate for a liquid crystal display device, which is formed by coating a conventional organic semiconductor material.

3A to 3G are process steps for manufacturing an array substrate for a liquid crystal display device having an organic thin film transistor having an organic semiconductor layer using a liquid organic semiconductor material according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

101 substrate 110 source electrode

113: drain electrode 117: pixel electrode

122: organic semiconductor material layer 130: organic insulating material layer

AA: Display Area NA: Non-Display Area

The present invention relates to a liquid crystal display device, and more particularly, to an array substrate for a liquid crystal display device using an organic semiconductor material and a method of manufacturing the same.

In recent years, as the society enters the information age, the display field that processes and displays a large amount of information has been rapidly developed, and recently, the thin film transistor (Thin) having excellent performance of thinning, light weight, and low power consumption has recently been developed. Film Transistor (TFT) type liquid crystal display (TFT-LCD) has been developed to replace the existing cathode ray tube (CRT).

The image realization principle of the liquid crystal display device uses the optical anisotropy and polarization property of the liquid crystal. As is well known, the liquid crystal has a thin and long molecular structure and optical anisotropy having an orientation in an array, and when placed in an electric field, the liquid crystal has an orientation of molecular arrangement depending on its size. This change is polarized. The liquid crystal display is an essential component of a liquid crystal panel formed by bonding an array substrate and a color filter substrate formed with pixel electrodes and common electrodes facing each other with the liquid crystal layer interposed therebetween. In addition, it is a non-light emitting device which artificially adjusts the arrangement direction of liquid crystal molecules through the electric field change between these electrodes and displays various images by using the light transmittance which is changed at this time.

Recently, the active matrix type, in which pixels, which are the basic units of image expression, are arranged in a matrix manner and a switching element is arranged in each pixel, is independently controlled, and is attracting attention in terms of resolution and video performance. One such thin-film transistor (TFT) is a thin-film transistor (Thin Firm Transistor Liquid Crystal Display Device).

In more detail, as shown in FIG. 1, which is an exploded perspective view of a general liquid crystal display device, the array substrate 10 and the color filter substrate 20 face each other with the liquid crystal layer 30 interposed therebetween. The array substrate 10 includes a plurality of gate lines 14 and data lines 16 arranged vertically and horizontally to the first transparent substrate 12 and upper surfaces thereof to define a plurality of pixel regions P. Thin film transistors T are provided at the intersections of the wirings 14 and 16 and are connected one-to-one with the pixel electrodes 18 provided in the pixel regions P. FIG.

In addition, the upper color filter substrate 20 facing the second transparent substrate 22 and its rear surface cover the non-display area of the gate line 14, the data line 16, the thin film transistor T, and the like. A grid-like black matrix 25 is formed that borders each pixel region P. The red, green, and blue color filter layers 26 are sequentially and repeatedly arranged to correspond to the pixel regions P in the grid. Is formed, and a transparent common electrode 28 is provided over the entire surface of the black matrix 25 and the red, green, and blue color filter layers 26.

Although not clearly shown in the drawings, these two substrates 10 and 20 are each sealed with a sealing agent or the like along the edges to prevent leakage of the liquid crystal layer 30 interposed therebetween. An upper and lower alignment layer is provided at the boundary between the substrates 10 and 20 and the liquid crystal layer 30 to provide reliability in the molecular alignment direction of the liquid crystal, and at least one outer surface of each of the substrates 10 and 20 has a polarizing plate. Attached.

In addition, a backlight is provided on the back of the liquid crystal panel to supply light. The on / off signal of the thin film transistor T is sequentially scanned and applied to the gate wiring 14. When the image signal of the data wiring 16 is transmitted to the pixel electrode 18 of the pixel region P, the liquid crystal molecules are driven by the vertical electric field therebetween, and various images are changed due to the change in the transmittance of light. I can display it.

Meanwhile, in the liquid crystal display device, glass substrates have been traditionally used for the first and second insulating substrates 12 and 22, which are the matrixes of the array substrate 10 and the color filter substrate 20. As small portable terminals such as personal digital assistants (PDAs) are widely used, liquid crystal panels using plastic substrates have been introduced that are lighter, lighter, and more flexible than glass so that they can be applied to them.

However, a liquid crystal panel using a plastic substrate has a high temperature process requiring a high temperature of 200 ° C. or higher, especially in the manufacture of an array substrate on which a thin film transistor, which is a switching element, is formed. Therefore, heat resistance and chemical resistance are inferior to that of a glass substrate. It is difficult to manufacture the array substrate using a plastic substrate, and thus, only the color filter substrate constituting the upper substrate is manufactured from the plastic substrate, and the array substrate, the lower substrate, is manufactured using a conventional glass substrate. .

In order to solve this problem, a technique for manufacturing an array substrate, which is characterized by forming a thin film transistor by performing a low temperature process below 200 ° C. using an organic semiconductor material, has recently been proposed. The manufacturing of the array substrate by such a low temperature process uses a coating apparatus rather than manufacturing using expensive vacuum deposition equipment, and thus the initial equipment cost is very low, and as a result, a reduction in manufacturing cost can be achieved. Naturally, the present invention is not limited to the production using the organic substrate, but may be manufactured using the organic substrate.

Hereinafter, a method of manufacturing an array substrate using an organic semiconductor material undergoing a low temperature process of 200 ° C. or less will be described.

In forming a pixel including a thin film transistor at a low temperature process of 200 ° C. or lower, the characteristics of the thin film transistor may be formed even by forming a metal material, an insulating film, a protective layer, or the like that form an interconnection with an electrode through low temperature deposition or coating. Does not affect much. However, when a semiconductor layer forming a channel is deposited by using a low temperature process using amorphous silicon, which is a commonly used semiconductor material, the internal structure of the semiconductor layer is not dense and important characteristics such as mobility play a role as a switching device. There is a problem that can not be reduced.

Therefore, in order to overcome this problem, it is proposed to form an organic semiconductor layer using an organic material having semiconductor characteristics, instead of a conventional semiconductor material such as amorphous silicon, such as amorphous silicon. Therefore, a liquid crystal display device including an organic thin film transistor, which is formed on a substrate by a coating method or the like, has been proposed.

A manufacturing process will be briefly described with reference to FIG. 2, which is a cross-sectional view of a manufacturing process of an array substrate for a liquid crystal display device, which is formed by coating a conventional organic semiconductor material.

First, the metal interconnection 53 and the electrode are formed on a substrate 51 made of glass or plastic, and then an organic semiconductor material is coated thereon to form an organic semiconductor material layer 60. The organic insulating material layer 65 is formed on the entire surface of the semiconductor material layer 60.

Subsequently, a cleaning process is performed to proceed the process for patterning the same. When the cleaning process is performed, the organic semiconductor material layer 60 has an adhesive force with the metal pattern and the substrate 51 made of glass or plastic. As a result, a large amount of peeling defects occur in which the organic semiconductor material layer 60 is peeled off from the edge of the substrate 51.

The reason why peeling of such an organic semiconductor material layer occurs will be described in more detail.

After the coating of the organic semiconductor material layer 60 on the substrate 51, the substrate 51 on which the organic semiconductor material layer 60 is formed is moved to the unit process equipment for the next step process for the subsequent process progress. In order to proceed with the process in each unit process equipment, the substrate 51 is loaded and unloaded into the stage of each unit process equipment by using a robot or the like. An impact is applied to the 51 and at the same time, warpage occurs in the substrate 51, and the impact and warpage are further caused to worsen the adhesion state of the organic semiconductor material layer 60 to the surface of the substrate 51.

Meanwhile, the organic semiconductor material constituting the organic semiconductor material layer 60 is very vulnerable to a developer or strip solution of a photoresist, which is a photosensitive material used in a chemical solution, for example, a general patterning process. An organic insulating material that does not react with the organic semiconductor material layer even when in contact with the organic semiconductor material layer is used because it cannot be formed, and is easily damaged by the material layer in contact therewith.

In order to proceed with the patterning, when a foreign material or the like is involved, a patterning failure occurs due to the foreign material, and thus a cleaning process is performed. As described above, the organic semiconductor is moved by moving the substrate 51 and loading and unloading the unit process equipment. Pure water (DI) having a predetermined pressure is sprayed onto the surface of the organic insulating material layer 65 more precisely in a state where the adhesion between the material layer 60 and the substrate 51 is further deteriorated. After the cleaning process is performed, nitrogen (N ₂ ) is injected using an air knife 80 or the like to remove water remaining on the substrate 51 after the cleaning process. The organic semiconductor material layer 60 is peeled off from the edges of the organic semiconductor material layer 60.

In this case, when the part peeled off from the substrate 51 is gradually enlarged in the process of continuing the manufacturing process, and peeling occurs to the display area AA, the organic semiconductor material layer remains only in the switching area in each pixel area. In the process of patterning, the portion where the organic semiconductor layer should be formed is completely separated from the substrate 51 so that a switching element is not formed.

Accordingly, the present invention, in the manufacture of an array substrate for a liquid crystal display device including an organic thin film transistor using a liquid organic semiconductor material, it is possible to prevent the peeling (peeling) of the organic semiconductor material layer occurring during the manufacturing process It aims at providing the manufacturing method.

In addition, another object is to improve the production yield by preventing peeling of the organic semiconductor material layer.

According to an aspect of the present invention, there is provided a method of manufacturing an array substrate for a liquid crystal display device having an organic semiconductor layer, the method including: forming source and drain electrodes spaced apart from each other on a substrate; Forming a pixel electrode on the substrate in contact with the drain electrode; Forming an organic semiconductor material layer by coating a liquid organic semiconductor material on the entire surface of the substrate over the pixel electrode; Exposing a surface corresponding to the substrate edge by removing the edge of the organic semiconductor material layer; Coating an organic insulating material over the organic semiconductor material layer on the entire surface to completely cover the top and side surfaces of the organic semiconductor material layer to form an organic insulating material layer; Forming a gate electrode over the organic insulating material layer; Forming a gate insulating film and an organic semiconductor layer by removing the organic insulating material layer and an organic semiconductor material layer below the organic insulating material layer exposed outside the gate electrode; Forming a gate wiring in contact with the gate electrode.

In this case, the organic semiconductor material layer and the organic insulating material layer is characterized in that formed by one coating method selected from slit coating, bar coating, spin coating.

In addition, exposing the surface corresponding to the edge of the substrate by removing the edge of the organic semiconductor material layer is characterized in that by the ER process, wherein the ER process is a mechanical chemical process of the arm A transition comprising a chemical solution for dissolving the organic semiconductor material layer surrounding the end portion is in contact with the organic semiconductor material layer on the substrate and linearly moves along the edge of the substrate to remove the organic semiconductor material layer formed on the substrate. . The substrate may include a display area and a non-display area outside the display area, and the organic semiconductor material layer removed by the ER process may be formed in the non-display area, and the organic semiconductor may be removed by the ER process. The material layer is characterized by having a width of 1 mm or more.

In addition, the organic insulating material layer is characterized in that made of one selected from polyvinyl pyrrolidone (PVP), fluoropolymer (fluoropolymer), polyvinyl alcohol (PVA).

The method may further include curing the organic semiconductor material layer remaining on the substrate after removing the edge of the organic semiconductor material layer to expose the surface corresponding to the substrate edge portion.

The method may further include forming a passivation layer having a gate contact hole exposing the gate electrode over the gate electrode and an open portion exposing the pixel electrode.

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

3A to 3G are process steps for manufacturing an array substrate for a liquid crystal display device having an organic thin film transistor having an organic semiconductor layer using a liquid organic semiconductor material according to an embodiment of the present invention. In this case, the drawing shows a part of the display area in which a plurality of pixel areas are defined, including the outermost part of the array substrate.

First, as shown in FIG. 3A, a metal material such as gold (Au), silver (Ag), copper (Cu), copper alloy, aluminum (Al) on the front surface of a substrate 101 made of transparent glass or plastic Forming a first metal layer (not shown) by depositing a metal material selected from aluminum alloys (AlNd), applying the first metal layer (not shown), applying a photoresist, exposing using a mask, developing a photoresist, A data line (not shown) extending in one direction by performing a patterning process including a predetermined unit process such as etching of the metal layer (not shown) and stripping of photoresist, and the data line (not shown) A source electrode 110 connected to the data line (not shown) and a portion of the pixel region P defined as a portion surrounded by a gate line (not shown) which is later formed and intersects with the gate line (not shown). Prescribed interval Drain electrodes 113 are formed to be spaced apart from each other to face each other.

Next, as shown in FIG. 3B, a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is formed on the substrate 101 on which the source and drain electrodes 110 and 113 are formed. Is deposited on the entire surface and patterned by the above-described mask process to form the pixel electrode 117 in contact with the drain electrode 113 formed in each pixel region P in the display area.

Next, as shown in FIG. 3C, the substrate 101 on which the pixel electrode 117 is formed for each pixel region P is coated with, for example, a slit coater and a bar coater. After positioning on a stage of one coating apparatus selected from a spin coater, a liquid organic semiconductor material such as pentacene or polythiophene is applied to the pixel electrode 117. The organic semiconductor material layer 120 is formed on the entire surface by coating the formed substrate 101.

Next, as illustrated in FIG. 3D, an edge removal (ER) is applied to a predetermined width of the edge of the substrate 101 on the stage of the coating apparatus before the organic semiconductor material layer 120 (FIG. 3C) is baked and cured. An edge removing process called a process is performed to remove the organic semiconductor material layer (120b in FIG. 3C) corresponding to the edge of the substrate 101 having a predetermined width so that the surface of the substrate 101 is more precisely displayed on the non-display area NA. It is positioned and exposes the surface of the substrate 101 corresponding to the predetermined width of the edge. In this case, the predetermined width may have a value smaller than the width of the non-display area NA. The minimum value is preferably 1 mm or more in order to have sufficient adhesion between the exposed substrate 101 and the organic insulating material layer formed in a later process. Do.

As shown in FIG. 4, the ER process is a process of a mechanical and chemical method of coating a layer of material, on each of the arms 191 extending up to four edges of the non-display area NA of the substrate 101. Corresponding to the portion where the arm 191 and the substrate 101 are in contact with each other, a soft cloth 193 in which a chemical liquid of a component for dissolving the semiconductor material is absorbed is provided. A portion corresponding to a predetermined width of the edge of the substrate 101 by removing the organic semiconductor material layer 122 corresponding to a predetermined width of the edge of the substrate 101 and performing linear reciprocating motions in parallel along four corners of the 101. Exposing the surface of the organic semiconductor material layer 122 to the outside of the organic semiconductor material layer 122.

In this case, a portion of the organic semiconductor material layer 122 that contacts the arm 191 of the ER processing apparatus, that is, a side surface of the organic semiconductor material layer may be damaged to cause deterioration of characteristics of the semiconductor layer. As a result, the organic semiconductor material layer (120b of FIG. 3D) formed in the non-display area NA of the substrate 101 is finally a portion to be etched and removed.

In the array substrate according to the related art, when peeling proceeds only to the non-display area located outside the display area, the organic semiconductor material layer of the non-display area may be substantially removed after patterning to form the organic semiconductor layer. Although the peeling progress is very fast, that is, the occurrence of lifting due to the peeling of the organic semiconductor material layer frequently occurs to the display area before the process of patterning the organic semiconductor material layer. It is a problem.

Next, as shown in FIG. 3E, the predetermined width of the edge portion is baked to cure the organic semiconductor material layer 122 by performing heat treatment on the substrate 101 exposed to the outside of the organic semiconductor material layer 122. The organic insulating material, for example, PVP, is formed on the edge of the non-display area NA of the substrate 101 exposed to the outside of the organic semiconductor material layer 122 and the baked and cured layer 122. (poly vinyl pyrrolidone), fluoropolymer (fluoropolymer), PVA (poly vinyl alcohol) by coating one of the selected to form an organic insulating material layer 130 on the front surface, and subsequently the heat treatment process the organic insulating material layer The 130 is fired to cure.

In this case, the organic insulating material layer 130 is formed to completely cover the side surface including the upper portion of the organic semiconductor material layer 122, so that the organic semiconductor material layer 122 is not exposed to the outside. It is characterized by being.

On the other hand, the organic insulating material is excellent in viscosity characteristics compared to the liquid organic semiconductor material, and the adhesive force with the substrate 101 of glass or plastic material is superior to the organic semiconductor material layer 122, so that the organic The peeling of the insulating material layer 130 from the surface of the substrate 101 does not occur.

In the case of the conventional array substrate, in the case of the organic semiconductor material layer, even if the organic insulating material layer is formed on the upper side thereof, the side surface of the organic semiconductor material layer does not completely cover the structure. Penetration into the interface between the substrate and the organic semiconductor material layer where peeling has occurred results in a structure that further accelerates the peeling of the organic semiconductor material layer, but in the case of the manufacturing method according to the present invention, ER As the process proceeds, the organic insulating material layer may be completely covered up to the side surface of the organic semiconductor material layer, thereby preventing defects in the semiconductor layer caused by peeling of the organic semiconductor material layer.

Next, as illustrated in FIG. 3F, a second metal layer (not shown) is formed by depositing a metal material, for example, molybdenum (Mo) or chromium (Cr), which is easily dry-etched on the organic insulating material layer 130. do.

Thereafter, a photoresist pattern (not shown) is formed by coating, exposing and developing the photoresist on the second metal layer, and dry etching is performed using the photoresist pattern (not shown) as an etch mask. The second metal layer (not shown) exposed to the outside, the organic insulating material layer (130 of FIG. 3E) and the organic semiconductor material layer (122 of FIG. 3E) below it are removed at the same time from the top to the bottom. The gate electrode 140, the gate insulating layer 133, and the organic semiconductor layer 125 having the same pattern shape are sequentially formed.

In this case, the source and drain electrodes 110 and 113, the organic semiconductor layer 125, the gate insulating layer 133, and the gate electrode (S) sequentially stacked on the pixel area P on the substrate 101 in the display area may be stacked. 140 forms an organic thin film transistor (Tr).

Next, as shown in FIG. 3g, one selected from an organic insulating material, for example, polyvinyl pyrrolidone (PVP), fluoropolymer, or polyvinyl alcohol (PVA) is coated on the front surface of the gate electrode 140. Forming a protective layer 145 having a gate contact hole 147 exposing the gate electrode 140 and an open portion op to expose most of the pixel electrode 117 in the pixel region P. do.

Next, a metal material having low resistance, for example, gold (Au), copper (Cu), a copper alloy, and aluminum (Al), on the protective layer 145 having the gate contact hole 147 and the opening op. And depositing aluminum alloy (AlNd) to form a third metal layer (not shown), and patterning it to contact the gate electrode 140 through the gate contact hole 147, and to connect the data line (not shown). By forming the gate wiring 150 crossing each other to define the pixel region P, the array substrate 101 for a liquid crystal display device having the organic thin film transistor Tr according to the present invention is completed.

In manufacturing an array substrate for a liquid crystal display device comprising a coating using a liquid organic semiconductor material according to the present invention, after forming an organic semiconductor material layer on the entire surface of the substrate, the edge portion of the substrate is removed by an ER process The organic insulating material layer is formed to completely cover the side surface of the organic semiconductor material layer in a state where the surface is exposed, thereby preventing peeling of the organic semiconductor material layer.

Claims (9)

Forming source and drain electrodes spaced apart from each other on the substrate and with data lines; Forming a pixel electrode on the substrate in contact with the drain electrode; Forming an organic semiconductor material layer by coating a liquid organic semiconductor material on the entire surface of the substrate over the pixel electrode; Exposing a surface corresponding to the substrate edge by removing the edge of the organic semiconductor material layer; Coating an organic insulating material on the entire surface of the organic semiconductor material layer to completely cover the top and side surfaces of the organic semiconductor material layer to form an organic insulating material layer; Forming a gate electrode over the organic insulating material layer; Forming a gate insulating film and an organic semiconductor layer by removing the organic insulating material layer and an organic semiconductor material layer below the organic insulating material layer exposed outside the gate electrode; Forming a gate wiring in contact with the gate electrode And a plurality of pixel electrodes formed on the substrate. The method of claim 1, And the organic semiconductor material layer and the organic insulating material layer are formed by one coating method selected from among slit coating, bar coating, and spin coating. The method of claim 1, Exposing the surface corresponding to the substrate edge by removing the edge of the organic semiconductor material layer by an ER process. The method of claim 3, wherein The ER process is a mechanical and chemical process that includes a chemical solution that dissolves the organic semiconductor material layer and wraps around the end of the arm in a linear motion and contacts the organic semiconductor material layer on the substrate and moves linearly along the edge of the substrate. And removing the organic semiconductor material layer formed on the substrate. The method of claim 3, wherein The substrate is a display area and a non-display area outside the display area is defined, wherein the organic semiconductor material layer removed by the ER process is formed in the non-display area manufacturing method of an array substrate for a liquid crystal display device. 6. The method of claim 5, And the organic semiconductor material layer removed by the ER process has a width of 1 mm or more. The method of claim 1, The organic insulating material layer is a manufacturing method of an array substrate for a liquid crystal display device, characterized in that made of one selected from PVP (poly vinyl pyrrolidone), fluoropolymer (fluoropolymer), PVA (poly vinyl alcohol). The method of claim 1, After removing the edge of the organic semiconductor material layer to expose a surface corresponding to the edge of the substrate, performing a heat treatment to harden the organic semiconductor material layer remaining on the substrate. Method of manufacturing a braided substrate. The method of claim 1, And forming a protective layer having a gate contact hole exposing the gate electrode over the gate electrode and an open portion exposing the pixel electrode over the gate electrode.

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