KR100794720B1 - Organic thin film transistor array panel and method for manufacturing the same - Google Patents

Abstract

An organic thin film transistor array panel and a method for manufacturing the same are provided to improve characteristics of a thin film transistor by using a photo-cross-linking gate insulating layer. A gate line(121) including a gate electrode is formed on a substrate(110). A data line(171) is isolated from the gate line and crosses the gate line. A source electrode(173) is connected to the data line. A drain electrode(175) is opposite to the source electrode. An organic semiconductor(154) comes in contact with the source electrode and the drain electrode. A gate insulating layer(140) is formed between the gate electrode and the organic semiconductor. The gate insulating layer includes a photo-cross-linking polyvinyl phenol which is formed by using a cross-linking agent and a photo-acid generator. The gate insulating layer is formed with a mixed solution including the polyvinyl phenol of 45-98 weight percent, the cross-linking agent of 1-15 weight percent, the photo-acid generator of 1-40 weight percent, and a solvent.

Description

Organic thin film transistor array panel and manufacturing method therefor {ORGANIC THIN FILM TRANSISTOR ARRAY PANEL AND METHOD FOR MANUFACTURING THE SAME}

1 is a layout view of an organic thin film transistor array panel according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of the organic thin film transistor array panel of FIG. 1 taken along the line II-II.

3 is a photograph showing contact holes of a gate insulating film formed by a photocrosslinking reaction,

4A and 4B are graphs showing characteristics of an organic thin film transistor manufactured according to an exemplary embodiment of the present invention.

The present invention relates to an organic thin film transistor array panel and a method of manufacturing the same.

Research into organic thin film transistors (O-TFTs) has been actively conducted as driving elements of next generation display devices.

The organic thin film transistor is formed by converting a semiconductor constituting the thin film transistor into an organic material instead of an inorganic material such as silicon (Si), and has a large process advantage because it can be manufactured in a single process at a low temperature. Since it can be manufactured in the form of a film, it is attracting attention as a core element of a flexible display.

The organic thin film transistor may have characteristics such as mobility and on / off current ratio due to various factors, among which the interface characteristics between the organic semiconductor and the gate insulating film are important. Do.

Thus, in order to improve the interface characteristics between the organic semiconductor and the gate insulating film, a gate insulating film made of an organic material is used. The gate insulating film made of an organic material may be formed by a method such as deposition, spin coating, slit coating or printing.

However, in order to form a gate insulating layer made of an organic material, such as a contact hole, a photolithography process using a photosensitive resin is required. This not only increases the manufacturing cost by adding a manufacturing process in the gate insulating film forming step, but also makes a high resolution pattern difficult.

Therefore, the technical problem to be achieved by the present invention is to solve the problem, and to form a high resolution pattern while reducing the manufacturing process and cost of the organic thin film transistor array panel.

An organic thin film transistor array according to an embodiment of the present invention includes a substrate, a gate line formed on the substrate and including a gate electrode, a data line insulated from and intersecting the gate line, a source electrode connected to the data line, and A drain electrode facing the source electrode, an organic semiconductor in contact with the source electrode and the drain electrode, and a gate insulating film positioned between the gate electrode and the organic semiconductor and including photo-crosslinked polyvinylphenol.

The gate insulating film may be formed in the form of a solution in which polyvinylphenol, a crosslinking agent and a photoacid generator are dissolved in a solvent.

The crosslinking agent may be an acetoxy methyl benzene compound.

The photoacid generator may be a triazine compound.

The gate insulating film may include 45 to 98% by weight of polyvinylphenol, 1 to 15% by weight of a crosslinking agent, and 1 to 40% by weight of a photoacid generator based on the total solid content of the gate insulating film.

A method of manufacturing an organic thin film transistor array according to an exemplary embodiment of the present invention includes forming a gate line on a substrate, forming a gate insulating film on the gate line, and a data line and a drain electrode including a source electrode on the gate insulating film. Forming an organic semiconductor in contact with the source electrode and the drain electrode, and forming the gate insulating film by applying a solution including polyvinylphenol, a crosslinking agent, and a photoacid generator. Forming an insulating film and exposing and developing the organic insulating film to form contact holes.

In the forming of the organic insulating layer, a solution obtained by dissolving the polyvinylphenol, the crosslinking agent and the photoacid generator in propylene glycol monomethyl ether acetate may be applied.

The crosslinking agent may be an acetoxy methyl benzene compound.

The photoacid generator may be a triazine compound.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, area, plate, etc. is over another part, this includes not only the part directly above the other part but also another part in the middle. On the contrary, when a part is just above another part, it means that there is no other part in the middle.

Next, an organic thin film transistor array panel according to an exemplary embodiment of the present invention will be described with reference to FIGS. 1 and 2.

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

As shown in the figure, a plurality of gate lines 121 are formed on an insulating substrate 110 made of transparent glass, plastic, or silicon.

The gate line 121 transmits a gate signal and mainly extends in a horizontal direction. Each gate line includes a plurality of gate electrodes 124 protruding upward and end portions 129 having a large area for connection with another layer or an external driving circuit. A gate driving circuit (not shown) for generating a gate signal may be mounted on a flexible printed circuit (not shown) attached to the substrate 110, mounted directly on the substrate 110, or mounted on a substrate ( 110 may be integrated. When the gate driving circuit is integrated on the substrate 110, the gate line 121 may extend to be directly connected to the gate driving circuit.

The gate line 121 is made of aluminum-based metals such as aluminum (Al) and aluminum alloys, silver-based metals such as silver (Ag) and silver alloys, gold-based metals such as gold (Au) and gold alloys, and copper (Cu ) And copper-based metals such as copper alloys, and molybdenum-based metals such as molybdenum (Mo) and molybdenum alloys, chromium (Cr), titanium (Ti), and tantalum (Ta). However, the gate line 121 may have a multilayer structure including two conductive layers (not shown) having different physical properties.

The side surface of the gate line 121 is inclined with respect to the surface of the substrate 110, and the inclination angle is preferably about 30 ° to 80 °.

A gate insulating layer 140 is formed on the gate line 121. The gate insulating layer 140 is made of an organic insulating material that can be crosslinked by light to form a pattern.

Such organic insulating materials include polyvinyl phenol, which may be exposed and crosslinked in the presence of a cross-linking agent and a photo-acid generator.

Next, a method of forming the gate insulating layer 140 will be described.

First, a gate insulating layer 140 including polyvinylphenol, a crosslinking agent, a photoacid generator, and a solvent is formed on the entire surface of the substrate on which the gate line 121 is formed.

The crosslinking agent may be an acetoxy methyl benzene compound, preferably 1,2,4,5-tetraacetoxy methyl benzene (1,2,4,5-tetraacetoxy methyl benzene). Examples of the triazine compounds include triazine compounds.

In addition, solvents capable of dissolving polyvinylphenol, crosslinking agents and photoacid generators include n-butyl acetate, isobutyl acetate, isoamyl acetate, and n- N-amyl acetate, methyl isobutyl ketone, n-butyl alcohol, ethylene glycol ethyl ether, ethylene glycol monomethyl ether ether, ethylene glycol ether, ethylene glycol propyl ether, ethylene glycol isopropyl ether, ethylene glycol monomethyl ether acetate, ethylene Ethylene glycol ethyl ether acetate, propylene glycol monomethyl ether acetate, pro Propylene glycol ethyl ether, propylene glycol propyl ether, propylene glycol monomethyl ether acetate, N, N-dimethyl formamide ), o-xylene and m-xylene, which may include at least one selected from among which propylene glycol monomethyl ether acetate is preferred.

The gate insulating layer 140 may be spin coated, off-set printing, screen printing, micro-contact printing or inkjet printing. It can form by such a method.

In this case, the gate insulating layer 140 may include about 45 to 98 wt% of polyvinylphenol, about 1 to 15 wt% of crosslinking agent, and about 1 to 40 wt% of photoacid generator based on the total content (solid content except solvent). Can be.

Next, a mask (not shown) is disposed on the gate insulating layer 140 and exposed to ultraviolet rays of about 365 nm. This exposure releases an acid-catalyst (H ⁺ ) from the photoacid generator, and the cross-linking reaction of the polyvinylphenol proceeds by the acid catalyst to form a photo-crosslinked polyvinylphenol.

The following chemical reaction scheme (I) illustrates this photocrosslinking reaction:

Wherein reactants 'A', 'B' and 'C' are poly (4-vinylphenol) (Mw = 10,000 to 30,000), 1,2,4,5-tetraacetoxy methylbenzene and triazine compounds, respectively, 'D' is the solvent, propylene glycol monomethyl ether acetate, and the product 'E' is light crosslinked polyvinylphenol.

Next, the gate insulating layer 140 is developed to form a plurality of contact holes 141. The contact hole 141 may be formed by developing a portion that is not exposed by the light blocking region of the mask.

The gate insulating layer 140 formed as described above exhibits high resolution.

3 is a photograph showing contact holes of a gate insulating film formed by a photocrosslinking reaction. Accordingly, it can be seen that fine contact holes having a diameter of about 8.75 μm may be formed in the gate insulating layer 140.

A plurality of data lines 171 and a plurality of drain electrodes 175 are formed on the gate insulating layer 140.

The data line 171 transmits a data signal and mainly extends in the vertical direction to cross the gate line 121. Each data line 171 includes a plurality of source electrodes 173 extending toward the gate electrode 124 and an end portion 179 having a large area for connection with another layer or an external driving circuit. A data driving circuit (not shown) for generating a data signal may be mounted on a flexible printed circuit board (not shown) attached to the substrate 110, mounted directly on the substrate 110, or integrated into the substrate 110. Can be. When the data driving circuit is integrated on the substrate 110, the data line 171 may be extended to be directly connected to the data driving circuit.

The drain electrode 175 is separated from the data line 171 and faces the source electrode 173 with respect to the gate electrode 124.

The data line 171 and the drain electrode 175 may include aluminum-based metals such as aluminum (Al) and aluminum alloys, silver-based metals such as silver (Ag) and silver alloys, gold-based metals such as gold (Au) and gold alloys, and copper ( It may be made of copper-based metals such as Cu) or copper alloys, molybdenum-based metals such as molybdenum or molybdenum alloys, nickel (Ni), chromium, tantalum (Ta), titanium (Ti), and indium tin oxide (ITO). However, they may have a multilayer structure including two conductive films (not shown) having different physical properties.

The side of the data line 171 and the drain electrode 175 may also be inclined at an inclination angle of about 30 ° to about 80 ° with respect to the surface of the substrate 110.

A plurality of island type organic semiconductors 154 are formed on the source electrode 173, the drain electrode 175, and the gate insulating layer 140. The organic semiconductor 154 is positioned on the gate electrode 124 and is in contact with the source electrode 173 and the drain electrode 175.

The organic semiconductor 154 may be formed of an oligomer or a polymer having a structure that can easily move electrons such as a conjugated system. The organic semiconductor 154 may be formed of a low molecular compound or a high molecular compound dissolved in an aqueous solution or an organic solvent, and a hydrophilic or hydrophobic functional group is applied to the low molecular conjugated compound to apply a low solubility low molecular compound to a solution process. It can be formed using a derivative (derivatives) combined.

The organic semiconductor 154 may be, for example, a derivative including a substituent of tetratracene or pentacene, or an oligothiophene in which 4 to 8 are connected through the 2 and 5 positions of a thiophene ring. oligothiophene, polythienylenevinylene, poly-3-hexylthiophene, phthalocyanine or thiophene, and the like.

A passivation layer 180 is formed on the data line 171, the drain electrode 175, and the organic semiconductor 154.

The passivation layer 180 is provided with a plurality of contact holes 182, 185, and 181 that expose the end portion 179 of the data line 171, the drain electrode 175, and the end portion 129 of the gate line 121, respectively. It is.

A plurality of pixel electrodes 191 and a plurality of contact assistants 81 and 82 are formed on the passivation layer 180. These may be made of transparent conductive materials such as ITO or IZO or reflective metals such as aluminum, silver or alloys thereof.

The pixel electrode 191 is physically and electrically connected to the drain electrode 175 through the contact hole 185 and receives a data voltage from the drain electrode 175. The pixel electrode 191 to which the data voltage is applied has a liquid crystal between the two electrodes by generating an electric field together with a common electrode (not shown) of another display panel (not shown) to which a common voltage is applied. The direction of the liquid crystal molecules in the layer (not shown) is determined. The pixel electrode 191 and the common electrode form a capacitor (hereinafter, referred to as a "liquid crystal capacitor") to maintain an applied voltage even after the thin film transistor is turned off.

The contact auxiliary members 81 and 82 are connected to the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 through the contact holes 181 and 182, respectively. The contact auxiliary members 81 and 82 compensate for and protect the adhesion between the end portions 179 and 129 of the data line 171 and the gate line 121 and the external device.

 One gate electrode 124, one source electrode 173, and one drain electrode 175 together with the organic semiconductor 154 form one thin film transistor (TFT), and the channel of the thin film transistor ( A channel is formed in the organic semiconductor 154 between the source electrode 173 and the drain electrode 175.

4A and 4B are graphs showing characteristics of an organic thin film transistor manufactured according to an exemplary embodiment of the present invention. As described above, it can be seen that the present embodiment exhibits excellent thin film transistor characteristics by improving the interfacial properties between the organic semiconductor and the gate insulating film by including the photocrosslinked gate insulating film and the organic semiconductor.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of the invention.

By including the photo-crosslinked gate insulating film as described above, the thin film transistor characteristics may be improved and the manufacturing process and cost may be reduced by patterning the gate insulating film without a separate photolithography process.

Claims (19)

Board, A gate line formed on the substrate and including a gate electrode, A data line insulated from and intersecting the gate line, A source electrode connected to the data line, A drain electrode facing the source electrode, An organic semiconductor in contact with the source electrode and the drain electrode, and A gate insulating film disposed between the gate electrode and the organic semiconductor and including a photo-crosslinked polyvinylphenol formed from a polyvinylphenol, a crosslinking agent and a photoacid generator Including; The gate insulating film is formed in the form of a solution in which the polyvinylphenol, the crosslinking agent and the photoacid generator are dissolved in a solvent, and 45 to 98% by weight of polyvinylphenol, 1 to 15% by weight, based on the total solid content of the gate insulating film. Containing a crosslinking agent and 1 to 40% by weight of a photoacid generator Organic thin film transistor array. delete In claim 1, And the crosslinker is an acetoxy methyl benzene compound. In claim 3, And the photoacid generator is a triazine compound. delete Forming a gate line on the substrate, Forming a gate insulating film on the gate line; Forming a data line and a drain electrode including a source electrode on the gate insulating layer, and Forming an organic semiconductor in contact with the source electrode and the drain electrode Including; Forming the gate insulating film Applying an aqueous solution of polyvinylphenol, a crosslinking agent and a photoacid generator in propylene glycol monomethyl ether acetate to form an organic insulating film, and Exposing and developing the organic insulating layer to form contact holes Method of manufacturing an organic thin film transistor array comprising a. delete In claim 6, The crosslinking agent is an acetoxy methylbenzene compound. In claim 6, The photoacid generator is a triazine compound manufacturing method of an organic thin film transistor array. In the method of manufacturing an organic thin film transistor array comprising forming a gate electrode, forming a source electrode and a drain electrode, and forming a semiconductor, Forming a gate insulating film between the step of forming the gate electrode and the step of forming the semiconductor, Forming the gate insulating film is polyvinylphenol. Forming a photoacid generator comprising a crosslinking agent and a triazine compound in solution form Method of manufacturing an organic thin film transistor array. In claim 10, The forming of the gate insulating film is a method of manufacturing an organic thin film transistor array comprising applying a solution of the polyvinylphenol, the crosslinking agent and the photoacid generator in propylene glycol monomethyl ether acetate. In claim 10, The crosslinking agent is an acetoxy methylbenzene compound. delete In an organic thin film transistor array comprising a gate electrode, a source electrode, a drain electrode and a semiconductor layer, A gate insulating film is formed between the gate electrode and the semiconductor layer, The gate insulating film is formed in the form of a solution in which polyvinylphenol, a crosslinking agent and a photoacid generator are dissolved in a solvent, and 45 to 98% by weight of polyvinylphenol, 1 to 15% by weight of a crosslinking agent based on the total solid content of the gate insulating film, and An organic thin film transistor array comprising photo-crosslinked polyvinylphenol formed from 1 to 40 weight percent photoacid generator. delete The method of claim 14, And the crosslinker is an acetoxy methyl benzene compound. The method of claim 14, And the photoacid generator is a triazine compound. delete In an organic thin film transistor array comprising a gate electrode, a source electrode, a drain electrode and a semiconductor layer, A gate insulating film is formed between the gate electrode and the semiconductor layer, The gate insulating film is formed from a photoacid generator comprising a polyvinylphenol, a crosslinking agent, and a triazine compound Organic thin film transistor array.

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