KR100953372B1 - Method of gas barrier layer formation using low temperature curing and method for manufacturing organic light emitting display using the same - Google Patents

Abstract

PURPOSE: A method for forming a gas barrier using a low temperature curing process and a method for manufacturing an organic light emitting device using the same are provided to simplify the manufacturing process using a sol-gel scheme in order to perform the whole process of an organic thin film transistor with a roll to roll process. CONSTITUTION: A gas-barrier layer(20) is coated on the upper side of a substrate(10) through a sol-gel spin coating process. The gas-barrier layer is baked at the temperature between 100 to 200°C. A wafer including the baked gas-barrier layer is cured in a solution(80) with an ultraviolet ray. The temperature of the curing process is between 50 to 100°C. The solution is OH-contained solution or an acid solution.

Description

Method of manufacturing gas light emitting layer using low temperature curing method and manufacturing method of organic light emitting device using same method

An embodiment of the present invention is a method of forming a gas barrier layer using low temperature curing and an organic electroluminescent device using the same in manufacturing a flexible organic light emitting display (OLED) The present invention relates to a manufacturing method, by forming a gas barrier layer using a sol-gel method capable of low temperature processing, and thus, the entire manufacturing process of the organic light emitting device can be manufactured by a R2R (Roll to Roll) process, and thus a flexible organic material having a decrease in production price. It relates to a method for manufacturing an electroluminescent device.

Flexible displays such as roll-type displays or e-newspapers, e-books, etc. are difficult to implement with an organic substrate coated with indium tin oxide (ITO), and thus a flexible substrate coated with indium tin oxide on a polymer film is used. It is manufactured by.

Display devices that can be used in implementing a flexible display using such a flexible substrate include an organic light emitting display (OLED), and the organic light emitting display has self-luminous, wide viewing angle, and high-speed response characteristics. It is important because it has such characteristics.

1 is a cross-sectional view showing a typical structure of an organic light emitting diode (OLED) manufactured using a conventional organic substrate.

As shown in FIG. 1, an organic light emitting diode (OLED) manufactured using an organic substrate is a planar organic light emitting diode using an organic substrate (1) having a transparent indium tin oxide (ITO) transparent electrode layer (2). The transport layer (3), the light emitting layer (4), the electron injection / transport layer (5), and the metal electrode layer (6) such as aluminum (Al) are deposited in this order, and then the organic electroluminescent device (OLED) In order to improve durability, an encapsulation structure (not shown) made of glass (not shown) or a metal material is mounted on the thin film metal (Al, etc.) electrode layer 6.

On the other hand, in the case of the organic light emitting display device using the glass substrate 1 on which the indium tin oxide transparent electrode layer 2 is formed, the organic substrate 1 sufficiently prevents penetration of moisture or oxygen, so that only the thin film metal layer 6 surface is formed. Although the encapsulation structure may be formed, the flexible organic electroluminescent device (OLED) uses a flexible substrate coated with indium tin oxide on a polymer film, so that the surface of the flexible metal substrate as well as the thin film metal electrode layer may be formed as a thin film. A passivation film should be formed. Because the flexible substrate having the indium tin oxide transparent electrode layer formed on the polymer film has a transmittance of water or oxygen 10 ³ to 10 ⁴ , unlike the organic substrate 1 having the indium tin oxide transparent electrode layer shown in FIG. 1. Because it's bigger.

2 is a cross-sectional view showing a representative structure of a flexible organic light emitting display device manufactured using a conventional polymer film.

As shown in FIG. 2, a flexible organic electroluminescent device (OLED) manufactured using a polymer film includes an organic material layer 3, 4, and 5 including a light emitting layer 4 through a flexible substrate 1 ′ or a metal electrode layer 6. However, when oxygen or moisture flows into the metal electrode layer 6, there is a problem that oxidation and corrosion of the electrode layers 2 and 6 occur while electroluminescence is performed. When the electrode layers 2 and 6 are oxidized, there is a problem that current leakage and short circuit occur, and pixel defects occur, resulting in a decrease in the lifetime of the display device itself. In addition, moisture or oxygen penetrated through both electrode layers 2 and 6 may cause oxidation or deterioration of the organic material layers 3, 4, and 5 including the light emitting layer 4, which performs a core function of the organic light emitting display device. The luminous efficiency is lowered.

Therefore, it is essential to fabricate an organic light emitting device that has a good gas permeability to protect the internal organic layer including the light emitting layer from moisture or oxygen, in particular, a protective film having a low gas permeability to moisture and oxygen. That is, the top emission type organic light emitting display device displaying an image through the surface on which the metal electrode layer is formed or the flexible organic light emitting display device having the flexible indium tin oxide transparent electrode layer have excellent light transmittance and refractive index and at the same time, the above-mentioned gas permeability characteristics. A long lifespan organic light emitting display device may be manufactured by forming a protective film in the form of a thin film.

As a conventional protective film material, a thin film of inorganic material such as silicon oxide (SiO ₂ ), silicon nitride (SiN _X ), silicon oxynitride (SiON), alumina (Al ₂ O ₃ ) and polyethylene tere have been used as a protective film of semiconductor devices. Thin films of polymer materials such as phthalate, polyvinylidene fluoride, polymethyl methacrylate, and polyimide have been used.

In the case of forming inorganic films such as SiO ₂ , SiN _X , and SiON, chemical vapor deposition (CVD) methods such as plasma enhanced chemical vapor deposition (PECVD) have been widely used. However, in the case of forming the inorganic thin film by the CVD method, even in the case of low temperature CVD, in order to increase the uniformity characteristic of the inorganic thin film, the deposition is performed at a temperature of 200 ° C. to 400 ° C., so that the organic material layer or the flexible substrate exhibiting the light emission characteristics of the organic light emitting device is obtained. There is a problem of deterioration. In this regard, Joangmal of NON-Crystalline Solids and Solids state Communications have reported a process for forming silicon nitride at low temperatures using PECVD. In addition, ULVAC and ANELVA of Japan have reported the formation of a protective film using CAT-CVD (Catalytic CVD), an equipment for forming a SiN _X film at a low temperature of 200 ° C or lower.

However, since HDT CVD (High Density Plasma CVD) using high density plasma or CAT-CVD using high temperature susceptor uses high density plasma, the organic material layers that are responsible for the light emitting function of the lower part formed are exposed to the plasma, so that the light emitting function is reduced. Deterioration or interfacial reaction between organic layers occurs. Among the interfacial reactions, the reaction between the metal electrode layer and the electron injection layer, which is an organic material layer, and the electron injection layer, and the organic light emitting layer may be a cause of leakage current. In addition, when the multilayer inorganic thin film is used as a protective film, a thicker protective film may cause a decrease in productivity, and there is a problem in that cracks are likely to occur due to tension generation in the protective film and thus may not serve as a protective film.

Therefore, this part remains a technical challenge, and various methods are applied to solve the problem, but it is not solved yet. Therefore, there is a demand for a method of forming a protective film in the form of a thin film having excellent light transmittance and refractive index and excellent gas permeability characteristics to protect internal organic layers including a light emitting layer from moisture or oxygen in a flexible organic light emitting device. .

An embodiment of the present invention is a gas barrier, which is a thin film-type protective film capable of low temperature processing and having excellent light transmittance and refractive index and at the same time having excellent gas permeability characteristics to protect internal organic material layers including a light emitting layer from moisture or oxygen. A method of forming a layer and a method of manufacturing an organic light emitting display device using the same are provided.

Another object according to an embodiment of the present invention is to coat the gas barrier layer formation that has been performed by conventional CVD using a Sol-gel method, and then, using a low temperature curing, from an outside at a process temperature of 150 ° C. or less. The present invention provides a gas barrier layer that is a protective film that effectively blocks the penetration of moisture and oxygen, and a flexible organic electroluminescent device having the protective film.

Another object according to an embodiment of the present invention is to form a gas barrier layer using a sol-gel method capable of low-temperature process, so that the entire manufacturing process of the organic light emitting device can be manufactured by a roll to roll (R2R) process To manufacture a flexible organic light emitting device having a drop of.

Characteristic of the method of forming a gas barrier layer using a low temperature curing in accordance with an embodiment of the present invention for achieving the above object is the step of coating a protective film on the substrate by a Sol-gel (Sol-gel) method, and It includes the step of putting the protective coating coated substrate in a solution containing OH radical (cure) to perform the curing.

Characteristic of the method of forming a gas barrier layer using a low temperature curing in accordance with an embodiment of the present invention for achieving the above object is the step of coating a protective film on the substrate by a Sol-gel (Sol-gel) method, and It includes the step of putting a protective film coated substrate in an acidic solution to perform a curing.

Preferably, the Sol-gel method is any one of spin coating, spray coating, dip coating, wiping, and roll coating. It is characterized by.

Preferably the solution containing the OH radical (radical) is characterized in that any one of water, hydrogen peroxide solution, ammonia water, KOH aqueous solution, NaOH aqueous solution, Ca (OH ₂ ) aqueous solution, Ba (OH ₂ ) aqueous solution.

Preferably the acid solution is characterized in that it comprises an ozone (O ₃ ) solution.

Preferably, the solution is characterized by performing curing by exposing ultraviolet (Ultraviolet: UV) to the solution.

Preferably, the solution is further characterized by further comprising the step of heating to a temperature of 20 ℃ or more, 150 ℃ or less using a heating element.

Preferably, the protective film further comprises a step of performing baking after coating.

Preferably, the protective film is characterized in that any one of an inorganic material thin film and a polymer material thin film.

Features of the method for manufacturing an organic light emitting device using a gas barrier layer using a low temperature curing in accordance with an embodiment of the present invention for achieving the above object is to form a transparent indium tin oxide (ITO) transparent electrode layer on the substrate And sequentially forming a hole injection / transport layer, an emission layer (EML), an electron injection / transport layer, and a metal electrode layer on the transparent electrode layer, and claim 1 or 2 above the metal electrode layer. Forming a gas barrier layer using low temperature curing through the process.

Preferably, when the substrate is a flexible substrate of a polymer film, a gas barrier layer using low temperature curing is first formed through the process of claim 1 or 2 before the transparent electrode layer is formed on the substrate.

As described above, a method of forming a gas barrier layer using low temperature curing and a method of manufacturing an organic light emitting device using the same according to an embodiment of the present invention may include a method of forming an organic thin film transistor using a sol-gel method. All processes can be R2R process, simplifying the manufacturing process, manufacturing cost is low, and fast productivity can be secured.

In addition, low temperature curing is possible to obtain a gate insulating film excellent in pure and dense silica (SiO ₂ ) characteristics even at a low temperature process of 150 ° C. or less, and an organic thin film using a flexible substrate that is susceptible to heat. The efficiency of the transistor can be improved.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments with reference to the accompanying drawings.

Referring to the accompanying drawings, a preferred embodiment of a method of forming a gas barrier layer using low temperature curing and a method of manufacturing an organic light emitting display device using the same according to the present invention will be described below. However, the present invention is not limited to the embodiments disclosed below, but can be embodied in various forms, and only the present embodiments are intended to complete the disclosure of the present invention and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations. Prior to the description, in the present specification, a sol-gel method including spin coating, spray coating, dip coating, wiping and roll coating as a method of forming a substrate. Because of this, all coating methods are possible, and for the sake of clarity and concise description, the spin coating will be limitedly described. However, note that this is not so limited.

First embodiment

3A to 3C are process charts illustrating a method of forming a gas barrier layer using low temperature curing according to an embodiment of the present invention.

The method of forming the gas barrier layer of the organic light emitting display device is first performed at 20 ° C. to 25 ° C. for 20 seconds through a Sol-gel spin coating process on the substrate 10, as shown in FIG. 3A. The gas barrier layer 20 is coated. In this case, as shown in FIG. 6, the gas barrier layer 20 may be formed of an inorganic material thin film such as silicon oxide (SiO ₂ ), silicon nitride (SiN _X ), silicon oxynitride (SiON), alumina (Al ₂ O ₃ ), or the like. 22) and at least one of a polymer material thin film 24 such as polyethylene terephthalate, polyvinylidene fluoride, polymethyl methacrylate, and polyimide, preferably, the gas barrier layer 20 is formed of an inorganic material thin film and The polymer material thin film is formed of a multi-layered structure, each laminated, and has a structure of about 3 to 5 layers. The inorganic material thin film 22 is formed thicker than the polymer material thin film 24.

Meanwhile, the sol-gel method such as spray coating, dip coating, wiping and roll coating as well as the coating of the gas barrier layer 20 through the spin coating. All coating processes are possible.

3B, the gas barrier layer 20 is baked at a temperature of 100 ° C. to 200 ° C. for about 2 hours.

3C, the wafer including the baked gas barrier layer 20 is placed in water (H ₂ O) 80, and ultraviolet light is exposed to the water 80 to about 50 ° C. Curing is performed at room temperature at 100 ° C. At this time, the water 80 used is a material of a preferred embodiment used for the treatment of the cure, not limited to this material, any solution or acidic solution containing OH radical (radical) is possible. For example, a solution containing OH radicals includes water (H ₂ O), hydrogen peroxide (H ₂ O ₂ ) water and ammonia water, KOH aqueous solution, NaOH aqueous solution, Ca (OH ₂ ) aqueous solution, Ba (OH ₂ ) aqueous solution. And acidic solutions include O ₃ (ozone) solutions having strong oxidizing power. The wavelength band of the exposed ultraviolet rays is preferably 200 nm to 405 nm, but various wavelength bands are possible within the scope of the technical idea of the present invention.

For reference, in the method of forming the gas barrier layer 20 according to the present invention, the baking process of FIG. 3B may be omitted.

As such, the embodiment of the present invention completely immerses and cures the substrate 10 coated with the gas barrier layer 20 in a solution containing OH radicals by using a Sol-gel method. There is a difference in the process from the existing method of reacting by evaporating a solution such as water or ammonia water. In addition, the low temperature (20 ~ 150 ℃) process is possible to process at room temperature (room temperature) is possible R2R (Roll to Roll) process is possible.

Second embodiment

4A to 4C are process charts illustrating a method of forming a gas barrier layer using low temperature curing according to another embodiment of the present invention.

The method of forming the gas barrier layer of the organic light emitting device is a gas for 20 seconds at a speed of 1500 rpm at a temperature of 20 ℃ ~ 25 ℃ through a Sol-gel spin coating process on the substrate 10, as shown in Figure 4a The barrier layer 20 is coated. In this case, as shown in FIG. 6, the gas barrier layer 20 may be formed of an inorganic material thin film such as silicon oxide (SiO ₂ ), silicon nitride (SiN _X ), silicon oxynitride (SiON), alumina (Al ₂ O ₃ ), or the like. 22) and at least one of a polymer material thin film 24 such as polyethylene terephthalate, polyvinylidene fluoride, polymethyl methacrylate, and polyimide, preferably, the gas barrier layer 20 is formed of an inorganic material thin film and The polymer material thin film is formed of a multi-layered structure, each laminated, and has a structure of about 3 to 5 layers. The inorganic material thin film 22 is formed thicker than the polymer material thin film 24.

Meanwhile, the sol-gel method such as spray coating, dip coating, wiping and roll coating as well as the coating of the gas barrier layer 20 through the spin coating. All coating processes are possible.

3B, the gas barrier layer 20 is baked at a temperature of 100 ° C. to 200 ° C. for about 2 hours.

3C, the wafer including the baked gas barrier layer 20 is placed in hydrogen peroxide (H ₂ O ₂ ) 90 and a heating element 100 such as a hot plate having a temperature of 50 ° C. to 100 ° C. Put on the hydrogen peroxide (H ₂ O ₂ ) (90) by heating to perform a curing at room temperature. At this time, the hydrogen peroxide 90 is used as a material of a preferred embodiment used for performing the curing, it is not limited to this material, any solution or acidic solution containing OH radical (radical) can be included. For example, a solution containing OH radicals includes water (H ₂ O), hydrogen peroxide (H ₂ O ₂ ) water and ammonia water, KOH aqueous solution, NaOH aqueous solution, Ca (OH ₂ ) aqueous solution, Ba (OH ₂ ) aqueous solution. And acidic solutions include O ₃ (ozone) solutions having strong oxidizing power.

For reference, in the method of curing the gas barrier layer 20 formed by the sol-gel method according to the present invention, the baking process of FIG. 4B may be omitted.

As such, in the exemplary embodiment of the present invention, the substrate 10 coated with the gas barrier layer 20 is completely immersed and cured in a solution containing OH radicals through a sol-gel method, and thus, conventional water or ammonia water. The process is different from the conventional method in which a solution such as evaporation is reacted. In addition, as in the curing method according to the first embodiment of the present invention described above, the curing method according to the second embodiment of the present invention is also capable of a low temperature process, so that R2R (Roll to Roll) process is possible in a short time. There is an advantage to cure.

Third Embodiment

5A to 5D are process diagrams illustrating a method of manufacturing an organic light emitting display device using a gas barrier layer using low temperature curing according to an embodiment of the present invention.

First, as shown in FIG. 5A, the gas barrier layer 20 is formed on the substrate 10 using low temperature curing by the method described in the first or second embodiment. In this case, when the substrate 10 is an organic substrate, the formation of the gas barrier layer 20 may be omitted. When the substrate 10 is a flexible substrate of a polymer film, the formation of the gas barrier layer 20 may be performed. This is necessary. That is, in the case of an organic substrate, since a penetration of moisture or oxygen is sufficiently prevented, a separate protective film is not necessary.

Subsequently, as shown in FIG. 5B, the transparent indium tin oxide (ITO) transparent electrode layer 30 is formed on the substrate 10 on which the gas barrier layer 20 is formed, and then α-NPD is formed as the hole injection / transport layer 40. Deposit 30nm thick, deposit Alq ₃ to 40nm with EML (Emission Layer) 50, deposit LiF to 2nm with electron injection / transport layer 60, and then use aluminum as metal electrode layer 70 (Al) metals were deposited one after another at a thickness of 140 nm.

In addition, as shown in FIG. 5C, the gas barrier layer may be formed on the metal electrode layer 70 by the method described in the first or second embodiment in order to improve durability against penetration of moisture, oxygen, and the like from the outside. 20 ') to form an organic light emitting display device.

As the gas barrier layers 20 and 20 'are formed using low temperature curing, the entire process of the organic light emitting diode can be manufactured by the R2R process. Accordingly, it is possible to secure a rapid productivity of the organic light emitting device, which may lead to a decrease in the production price.

Although the technical spirit of the present invention described above has been described in detail in a preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a cross-sectional view showing a representative structure of an organic light emitting diode (OLED) manufactured using a conventional organic substrate

2 is a cross-sectional view showing a representative structure of a flexible organic light emitting display device manufactured using a conventional polymer film

3A to 3C are process flowcharts illustrating a method of forming a gas barrier layer using low temperature curing according to an embodiment of the present invention.

4A to 4C are process charts showing a method of forming a gas barrier layer using low temperature curing according to another embodiment of the present invention.

5A to 5D are process diagrams illustrating a method of manufacturing an organic light emitting display device using a gas barrier layer using low temperature curing according to an embodiment of the present invention.

6 is a cross-sectional view showing a detailed structure of a gas barrier layer formed according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

10: substrate 20, 20 ': gas barrier layer

22: inorganic material thin film 24: polymer material thin film

30: ITO transparent electrode layer (anode) 40: hole injection / transport layer

50: light emitting layer 60: electron injection / transport layer

70: metal electrode layer 80: water (H ₂ O)

90: hydrogen peroxide (H ₂ O ₂ ) 100: heating element

Claims (15)

Coating a protective film on the substrate using a Sol-gel method; And placing the protective film-coated substrate in a solution containing OH radicals and performing curing. Coating a protective film on the substrate using a Sol-gel method; And putting the protective film-coated substrate into an acidic solution to perform curing. The method according to claim 1 or 2, The Sol-gel method is any one of spin coating, spray coating, dip coating, wiping, and roll coating. A method of forming a gas barrier layer using low temperature curing. The method of claim 1, The solution containing the OH radical (radical) is any one of water, hydrogen peroxide solution, ammonia water, KOH aqueous solution, NaOH aqueous solution, Ca (OH ₂ ) aqueous solution, Ba (OH ₂ ) aqueous solution using a low temperature curing Method of forming a gas barrier layer. The method of claim 2, The acid solution is a method of forming a gas barrier layer using a low temperature curing, characterized in that containing an ozone (O ₃ ) solution. The method according to claim 1 or 2, A method of forming a gas barrier layer using low temperature curing, wherein the solution is cured by exposing ultraviolet light (Ultraviolet: UV) to the solution. The method of claim 6, The ultraviolet light is a method of forming a gas barrier layer using low temperature curing, characterized in that the wavelength range of 200nm or more and 405nm or less. The method according to claim 1 or 2, Method for forming a gas barrier layer using a low temperature curing characterized in that it further comprises the step of heating the solution to a temperature of 20 ℃ or more, 150 ℃ or less using a heating element. The method according to claim 1 or 2, The method of forming a gas barrier layer using low temperature curing, further comprising the step of performing baking after coating the protective film. The method according to claim 1 or 2, The protective film is a method of forming a gas barrier layer using a low temperature curing, characterized in that any one of an inorganic material thin film and a polymer material thin film. The method according to claim 1 or 2, The protective film is a gas barrier layer forming method using a low temperature curing, characterized in that the inorganic material thin film and a polymer material thin film is laminated in a multi-layer structure. Forming a transparent indium tin oxide (ITO) transparent electrode layer on the substrate, Sequentially forming a hole injection / transport layer, an emission layer (EML), an electron injection / transport layer, and a metal electrode layer on the transparent electrode layer; Forming a gas barrier layer using a low temperature curing by the process of claim 1 or 2 on the metal electrode layer of the organic light emitting device using a gas barrier layer using a low temperature curing Manufacturing method. The method of claim 12, The substrate is a method of manufacturing an organic light emitting device using a gas barrier layer using a low temperature curing, characterized in that the glass substrate or a flexible substrate. The method of claim 13 When the substrate is a flexible substrate of a polymer film, a gas barrier using low temperature curing is formed by first forming a gas barrier layer using low temperature curing through the process of claim 1 before forming a transparent electrode layer on the substrate. Method for manufacturing an organic light emitting device using the layer. The method of claim 13 In the case where the substrate is a flexible substrate of a polymer film, the gas barrier using low temperature curing may be formed by first forming a gas barrier layer using low temperature curing through the process of claim 2 before forming the transparent electrode layer on the substrate. Method for manufacturing an organic light emitting device using the layer.

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