KR100659096B1 - Organic tft, flat panel display therewith, and manufacturing method of the organic tft - Google Patents

Abstract

An organic TFT, a flat panel display therewith, and a method for manufacturing an organic TFT are provided to prevent removal of a metal layer in a patterning process by forming an adhesive layer including an inorganic material between a plastic substrate and a metal layer. A source electrode(130a) and a drain electrode(130b) are formed on an upper surface of a substrate(110). An adhesive layer(120) is inserted between the substrate and the source and drain electrodes. An organic semiconductor layer(140) is connected with the source and the drain electrodes. A gate electrode(160) is isolated from the organic semiconductor layer. The adhesive layer includes one of a silicon nitride layer or a silicon oxide layer. The substrate is formed with plastics.

Description

Organic thin film transistor, flat panel display device having same, manufacturing method of the organic thin film transistor {organic TFT, flat panel display therewith, and manufacturing method of the organic TFT}

1 is a cross-sectional view schematically showing an organic thin film transistor according to an exemplary embodiment of the present invention.

2 is a schematic cross-sectional view of an organic thin film transistor according to another exemplary embodiment of the present invention.

3 is a cross-sectional view schematically illustrating a flat panel display device having an organic thin film transistor according to another exemplary embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic thin film transistor and a flat panel display device having the same, and more particularly, to an organic thin film transistor for improving bonding between a plastic substrate and a metal layer, a flat panel display device having the same, and a method of manufacturing the organic thin film transistor.

Thin Film Transistors (hereinafter referred to as TFTs) used in flat panel display devices, such as liquid crystal display devices, organic electroluminescent display devices, or inorganic electroluminescent display devices, drive pixels and switching elements that control the operation of each pixel. It is used as a drive element.

Such a conventional TFT has a source / drain region doped with a high concentration of impurities, a semiconductor layer having a channel region formed between the source / drain region, and a region insulated from the semiconductor layer and corresponding to the channel region. And a gate electrode and a source / drain electrode in contact with the source / drain regions, respectively.

On the other hand, the demand for TFT is required not only in display devices but also in various fields. For example, recently, it is used in various fields such as a smart card, an E-paper, a roll-up display, and the like, which is required for thin electronic devices provided therein. Since the common feature is flexibility, the substrate forming the thin film transistor is required to be a substrate having flexibility such as a plastic substrate.

However, when the plastic substrate is used as the substrate of the thin film transistor, the adhesion between the plastic substrate and the metal layer on which the source / drain electrodes are formed is poor, so when the organic semiconductor layer on the metal layer is patterned to form a channel, only the organic semiconductor layer is patterned. The problem arises that the metal layer is also removed at the same time.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an organic thin film transistor having a structure for improving bonding between a plastic substrate and a metal layer, a flat panel display device having the same, and a method of manufacturing the organic thin film transistor.

The organic thin film transistor for solving the technical problem to be achieved by the present invention is a substrate; A source / drain electrode formed on the substrate; An adhesive layer interposed between the substrate and the source / drain electrodes; An organic semiconductor layer in contact with the source / drain electrode; And a gate electrode insulated from the organic semiconductor layer.

A flat panel display device for solving the above technical problem to be achieved by the present invention is a substrate; A metal wiring formed on the substrate; And an adhesive layer interposed between the substrate and the metal wiring.

The organic thin film transistor manufacturing method for solving the technical problem to be achieved by the present invention comprises the steps of forming an adhesive layer on the upper portion of the substrate; Forming a source / drain electrode on the adhesive layer; Forming an organic semiconductor layer in contact with the source / drain electrodes; Irradiating a portion of the organic semiconductor layer by irradiating a laser beam on the organic semiconductor layer; Forming an insulating layer on the organic semiconductor layer; And forming a gate electrode on the insulating layer.

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

1 is a cross-sectional view schematically showing an organic thin film transistor according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the organic thin film transistor is provided on the substrate 110. The substrate 110 may be, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), polyether imide, polyphenylene Plastic materials such as polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose tri acetate (TAC), cellulose acetate propinonate (CAP) Can be.

An adhesive layer 120 is provided on the substrate 110. The adhesive 120 may be formed of an inorganic material, for example, silicon nitride (SiNx) or silicon oxide (SiO 2). The adhesive layer 120 is provided to reinforce the adhesive force between the plastic substrate 110 and the metal layer forming the source / drain electrodes 130a and b.

Argon (Ar) and oxygen are formed on the surface of the plastic substrate 110 without the adhesive layer 120 as a method for enhancing the adhesion between the plastic substrate 110 and the metal layers forming the source / drain electrodes 130a and b. Adhesion may be enhanced by forming a plasma mixed with (O 2) to form a rough surface, or by roughly forming the surface of the plastic substrate 110 by rough scratching.

Thereafter, source / drain electrodes 130a and b are formed on the adhesive layer 120. The source / drain electrodes 130a and b may be transparent electrodes made of a transparent conductive material such as ITO, IZO, ZnO or In 2 O 3, and may be Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, and the like. It may be composed of a reflective electrode containing these compounds and a transparent electrode formed thereon.

After the source / drain electrodes 130a and b are formed on the adhesive layer 120, the organic semiconductor layer 140 is entirely formed on the source / drain electrodes 130a and b. Organic semiconductor layer 140 is a polymer, polythiophene and derivatives thereof, polyparaphenylenevinylene and derivatives thereof, polyparaphenylene and derivatives thereof, polyfluorene and derivatives thereof, polythiophenevinylene and derivatives thereof , Polythiophene-heterocyclic aromatic copolymers and derivatives thereof, and as low molecular weights, pentacene, tetracene, oligoacene and derivatives thereof of naphthalene, alpha-6-thiophene, alpha-5-thiophene Oligothiophene and derivatives thereof, phthalocyanine and derivatives thereof with or without metal, pyromellitic dianhydride or pyromellitic diimide and derivatives thereof, perylenetetracarboxylic acid dianhydride or per Relenetetracarboxylic diimide and derivatives thereof.

After the organic semiconductor layer 140 is formed, a channel is formed in the organic semiconductor layer 140 by using laser ablation technology. Laser etching is a method of etching a film made of organic material, inorganic material, etc. by irradiating a laser beam, and recently, it has been widely used for patterning processes of various electronic devices. After the organic semiconductor layer 140 is formed, a predetermined portion of the layer 140 is irradiated with a laser of a predetermined intensity to pattern only the semiconductor material of that portion. The channel forming method is not necessarily limited to the laser patterning method, and in addition, the channel may be formed by various methods.

As shown in FIG. 1, an adhesive layer 120 made of an inorganic material is formed between the plastic substrate 110 and the source / drain electrodes 130a and b to strengthen their bonding force, thereby forming the source / drain electrodes 130a and b. When the organic semiconductor layer 140 formed on the upper layer is patterned through the LAT, the source / drain electrodes 130a and b may be prevented from being removed together.

After the channel formed organic semiconductor layer 140 is formed, a gate insulating layer 150 for insulating the gate electrode 160 to be formed later is formed on one surface thereof. The gate insulating layer 150 may be made of, for example, an inorganic insulating layer such as SiO 2, SiN x, Al 2 O 3, Ta 2 O 5, BST, PZT, etc. by chemical vapor deposition or sputtering. , PS (polystyrene), phenolic polymer, acrylic polymer, imide polymer such as polyimide, arylether polymer, amide polymer, fluorine polymer, p-xylene polymer, vinyl alcohol polymer, parylene ( parylene), and an organic insulating layer made of a polymer material such as a compound containing one or more thereof, and in some cases, may be formed of a plurality of layers. It is preferred that the material be selected from a material which is excellent and has the same or similar thermal expansion coefficient as the substrate.

After the gate insulating layer 150 is formed, the gate electrode 160 is formed thereon. The gate electrode 160 may be a conductive metal such as MoW, Al, Cr, Al / Cr, or a conductive polyaniline, a conductive poly pirrole, a conductive polythiopjene, or a polyethylene dioxythiophene. Various conductive polymers such as PEDOT and polystyrene sulfonic acid (PSS) may also be used, such as adhesion to the substrate 110, flatness of the thin films formed on the gate electrode 160, processability for patterning, and subsequent processing. Appropriate materials should be selected in consideration of their resistance to chemicals.

2 is a schematic cross-sectional view of an organic thin film transistor according to another exemplary embodiment of the present invention.

Referring to FIG. 2, the organic thin film transistor is provided on the substrate 110 of the material described above.

An adhesive layer 120 is provided on the substrate 110. The adhesive 120 may be formed of an inorganic material, for example, silicon nitride (SiNx) or silicon oxide (SiO 2). The adhesive layer 120 is provided to reinforce the adhesive force between the plastic substrate 110 and the metal layer forming the source / drain electrodes 130a and b and the metal wiring 130c.

Argon (Ar) and oxygen are formed on the surface of the plastic substrate 110 without the adhesive layer 120 as a method for enhancing the adhesion between the plastic substrate 110 and the metal layers forming the source / drain electrodes 130a and b. Adhesion may be enhanced by forming a plasma mixed with (O 2) to form a rough surface, or by roughly forming the surface of the plastic substrate 110 by rough scratching.

Thereafter, the source / drain electrodes 130a and b and the metal wire 130c are formed on the adhesive layer 120.

After the source / drain electrodes 130a and b and the metal wiring 130c are formed on the adhesive layer 120, the organic semiconductor layer 140 is disposed on the source / drain electrodes 130a and b and the metal wiring 130c. Is formed. Thereafter, the organic semiconductor layer 140 formed on the metal line 130c may be etched in various ways.

After the organic semiconductor layer 140 is formed, a gate insulating layer 150 for insulating the gate electrode 160 to be formed later is formed on one surface thereof.

After the gate insulating layer 150 is formed, the gate electrode 160 is formed thereon.

3 is a cross-sectional view schematically illustrating an organic electroluminescent device as an example of a pixel unit included in a flat panel display device having a thin film transistor according to another exemplary embodiment of the present invention. The unit 200 is included.

The organic thin film transistor unit 100 includes a substrate 110, an adhesive layer 120, source / drain electrodes 130a and b, an organic semiconductor layer 140, a gate insulating layer 150, a gate electrode 160, and a protective layer. And 170.

The pixel unit 200 includes a first electrode layer 210, a pixel defining layer 220, an organic electroluminescent unit 230, and a second electrode layer 240.

Since the substrate 110 to the gate electrode 160 are the same as those of FIG. 1, description thereof will be omitted.

After the gate electrode 160 is formed, a protective layer 170 such as a passivation layer and / or a planarization layer for insulating and / or planarizing the organic thin film transistor unit 100 is formed thereon.

The first electrode layer 210 is formed on the passivation layer 170, and the first electrode layer 210 is in electrical communication with the organic thin film transistor unit 100 through the via hole 211 formed in the passivation layer 170. Achieve

The first electrode layer 210 may be configured in various ways. For example, the first electrode layer 210 may be a transparent electrode made of a transparent conductive material such as ITO, IZO, ZnO, or In 2 O 3. Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr and a reflective electrode comprising a compound thereof and may be composed of a transparent electrode formed thereon, the first electrode layer 210 is a single layer, Various modifications are possible, including, but not limited to, bilayers.

After the first electrode layer 210 is formed, a pixel defining layer 220 for defining a pixel opening is formed on the top. After the pixel defining layer 220 is formed, the organic electroluminescent unit 230 is provided in at least a region including the pixel opening. As the organic electroluminescent unit 230, a low molecular or polymer organic film may be used. When the low molecular organic film is used, a hole injection layer (HIL), a hole transport layer (HTL), and an emission layer (EML) are emitted. ), An electron transport layer (ETL), an electron injection layer (EIL), or the like, may be formed by stacking a single or a complex structure, and the usable organic material may be copper phthalocyanine (CuPc). , N, N-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine (N, N'-Di (naphthalene-1-yl) -N, N'-diphenyl-benzidine: NPB), Various applications are possible, including tris-8-hydroxyquinoline aluminum (Alq3). These low molecular weight organic films are formed by the vacuum deposition method.

In the case of the polymer organic film, the structure may include a hole transporting layer (HTL) and a light emitting layer (EML). In this case, PEDOT is used as the hole transporting layer, and PPV (Poly-Phenylenevinylene) and polyfluorene Polymer organic materials such as polyfluorene) may be used and may be formed by screen printing or inkjet printing. The organic layers constituting the organic electroluminescent unit are not necessarily limited thereto, and various embodiments may be applied.

Similarly, in the case of the first electrode layer 210, the second electrode layer 240 may have various configurations depending on the polarity and the light emission type of the electrode layer. That is, when the second electrode layer 240 acts as a cathode electrode and the light emission type is a bottom emission type, the second electrode layer 240 is Li, Ca, LiF / Ca, LiF / Al, Al, Ag, Mg, and their It may be composed of one or more layers of a material having a small work function, such as a compound, and in the case of a top emission type, an organic electroluminescence unit using Li, Ca, LiF / Ca, LiF / Al, Al, Ag, Mg, and a compound thereof. After forming an electrode for matching the work function on one surface of the 230, a transparent electrode such as ITO, IZO, ZnO, In 2 O 3, or the like may be formed thereon, and the second electrode layer 240 may be entirely formed. It is possible to take various configurations without being limited thereto. Meanwhile, in the above embodiment, the first electrode layer 210 serves as an anode electrode and the second electrode layer 240 serves as a cathode electrode, but various configurations are possible, such as having opposite polarities. Do.

The above embodiments are examples for describing the present invention, and the present invention is not limited thereto. The thin film transistor according to the present invention may be applied to a liquid crystal display device as well as an organic electroluminescent display device, and an image may be displayed in addition to a flat panel display device. Various modifications may be considered, such as mounting to a driver circuit not implemented.

As described above, in the present invention, an adhesive layer made of an inorganic material is formed between the plastic substrate and the metal layer to strengthen the bonding strength thereof, and thus, when the organic semiconductor formed on the metal layer is patterned through the LAT, the metal layer may be prevented from being removed together. have.

Claims (9)

Board; A source / drain electrode formed on the substrate; An adhesive layer interposed between the substrate and the source / drain electrodes; An organic semiconductor layer in contact with the source / drain electrode; And An organic thin film transistor comprising a gate electrode insulated from the organic semiconductor layer. The method of claim 1, wherein the adhesive layer An organic thin film transistor comprising at least one of silicon nitride and silicon oxide. The method of claim 1 or 2, wherein the substrate An organic thin film transistor, characterized in that the plastic. Board; A source / drain electrode formed on the substrate, an adhesive layer interposed between the substrate and the source / drain electrode, an organic semiconductor layer in contact with the source / drain electrode, and a gate electrode insulated from the organic semiconductor layer Organic thin film transistor; And And a display device electrically connected to the organic thin film transistor. The method of claim 4, wherein the adhesive layer A flat panel display device comprising at least one of silicon nitride and silicon oxide. The method of claim 4 or 5, wherein the substrate Flat panel display device characterized in that the plastic. Forming an adhesive layer on top of the substrate; Forming a source / drain electrode on the adhesive layer; Forming an organic semiconductor layer in contact with the source / drain electrodes; Irradiating a portion of the organic semiconductor layer by irradiating a laser beam on the organic semiconductor layer; Forming an insulating layer on the organic semiconductor layer; And Forming a gate electrode on the insulating layer. The method of claim 7 or 8, wherein the adhesive layer A method for fabricating an organic thin film transistor comprising at least one of silicon nitride and silicon oxide. The method of claim 7, wherein the substrate An organic thin film transistor manufacturing method, characterized in that the plastic.

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