KR100742561B1 - Method for selective growth of encapsulation layer and organic light emitting diode and organic thin film transistor using the same - Google Patents

Abstract

The present invention relates to a method for selectively forming an encapsulation film, and an organic light emitting device and an organic thin film transistor using the same. The method for selectively forming an encapsulation film according to the present invention may include forming a device having an organic layer on the substrate after treating the substrate with an inhibitor, and forming a protective film selectively covering the device by the action of the inhibitor. According to the present invention, the lifespan of an element including organic material layers such as an organic light emitting element and an organic thin film transistor can be improved.

Organic thin film, encapsulation, parylene, selective deposition, inhibitor, organic light emitting device, organic thin film transistor

Description

Method for selective growth of encapsulation layer and organic light emitting diode and organic thin film transistor using the same}

1 is a cross-sectional view schematically showing an organic light emitting device manufactured using a method for selectively forming an encapsulation film according to an embodiment of the present invention.

2A to 2C are cross-sectional views illustrating a method for selectively forming an encapsulation film according to an embodiment of the present invention.

3 is a graph showing a change in luminance-voltage characteristic of an organic light emitting device manufactured by a method of selectively forming an encapsulation film according to an embodiment of the present invention.

4 is a graph showing the lifespan of the organic light emitting device manufactured by the method for selectively forming an encapsulation film according to an embodiment of the present invention.

5 is a cross-sectional view illustrating an organic thin film transistor manufactured using a method for selectively forming an encapsulation film according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

10: Substrate

20: inhibitory layer / inhibitor

30: organic layer

40: shield

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of depositing an encapsulation film, and more particularly, to a method for selectively forming an encapsulation film of an element having an organic material layer, such as an organic light emitting device and an organic thin film transistor, and an organic light emitting device and an organic thin film transistor using the method. It is about.

Organic light emitting diodes have a structure having an organic light emitting layer between an anode and a cathode. The organic light emitting device has excellent advantages such as high luminous efficiency, wide viewing angle, fast response speed, and high contrast. However, the material used for the organic light emitting layer has a very sensitive property such as water, oxygen, and moreover, the electrodes of the organic light emitting device has a disadvantage that the characteristics deteriorate due to oxidation. As a result, when the general organic light emitting device is operated in the air, the life of the device is shortened.

In order to solve the above-mentioned problems, researches on encapsulation of organic light emitting diodes have been conducted. One of the encapsulation methods of the conventional organic light emitting device is a metal cap or shield glass with a moisture absorbent is applied to the organic light emitting device by using an ultraviolet curing epoxy-based adhesive. By attaching to block moisture and oxygen of the organic light emitting device or to prevent degradation of the device. However, the conventional method described above has a difficulty in that the thinning of the device is impossible due to the thickness of the metal lid or shield glass of the encapsulation used. In addition, the conventional method has a disadvantage that it is impossible to be applied to the next-generation organic light emitting device capable of bending.

In order to alleviate the above-mentioned disadvantages, a method using a plastic cap, a method of forming an organic or inorganic composite film using physical or chemical vacuum deposition, or a method of spin coating a siloxane-based polymer directly onto an organic light emitting device has been proposed. . Among these various types of encapsulation methods, a method of forming a polymer thin film by depositing and polymerizing a liquid or solid monomer using a vacuum deposition equipment, a method of encapsulating a device by vacuum depositing a polymer, and an inorganic material. A method of forming an inorganic thin film by depositing a film and a method of using an organic / inorganic composite film have been widely studied. However, the above-described conventional methods can obtain a relatively excellent protective film, but the disadvantage is that the polymer thin film is deposited on the entire substrate. That is, there is an inconvenience in that a part of the protective film deposited on the entire substrate must be removed for wiring between the device and the external device.
In order to improve the inconvenience described above, a method of controlling deposition by masking a portion that does not require deposition before deposition of a protective film has also been proposed. Although this method can effectively control the deposition, it is not easy to control the minute portion, and also there is a disadvantage that peeling phenomenon of the thin film constituting the device may occur when removing the masking portion after forming the protective film. Another conventional technique is a method of performing dry etching after the formation of a thin film to remove a thin film in a portion where a protective film is not required. However, this conventional method has the disadvantage that the process is complicated and expensive.

An object of the present invention is to provide a method for selectively forming an encapsulation thin film on an element such as an organic light emitting device or an organic thin film transistor.

Still another object of the present invention is to provide a method for selectively depositing an encapsulation thin film of a plastic-based organic light emitting device that can be bent.
Still another object of the present invention is to provide an organic light emitting device and an organic thin film transistor which are manufactured using the method for selectively forming an encapsulation film.

According to a first aspect of the present invention to achieve the above object, a step of forming a device having an organic layer on the substrate after treating the substrate with an inhibitor; And forming a protective film that selectively covers the device by the action of an inhibitor.

It is preferable that the said protective film is a parylene thin film. The inhibitor is formed of a solution containing iron ions, and the solvent of the solution is preferably an alcohol or a mixed solvent of water and a polar solvent.

Treating the substrate with an inhibitor includes dipping or printing the substrate using a solution having a concentration of 0.1 to 30%.

According to a second aspect of the present invention, there is provided a semiconductor device comprising: a suppression layer located in a first region on a substrate; A first electrode, an organic layer, and a second electrode positioned in a second region on the substrate and having a stacked structure; And a protective film exposing the suppression layer and selectively covering the first electrode, the organic layer, and the second electrode.

According to a third aspect of the present invention, there is provided a semiconductor device comprising: a suppression layer located in a first region on a substrate; A gate electrode, a source / drain electrode and an organic semiconductor layer positioned in the second region on the substrate; And a protective film exposing the suppression layer and selectively covering the gate electrode, the source / drain electrode, and the organic semiconductor layer.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following examples are provided to fully understand the present invention for those skilled in the art, and in describing the present invention, detailed descriptions of related well-known functions or configurations are unnecessary to the gist of the present invention. If it is determined that it can be blurred, its detailed description is omitted. It should be noted that the same elements in the drawings are represented by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In addition, the thickness or size of each layer in the drawings is exaggerated for convenience and clarity of description and may differ from the actual film thickness or size.

1 is a cross-sectional view schematically showing an organic light emitting device manufactured using a method for selectively forming an encapsulation film according to an embodiment of the present invention.

Referring to FIG. 1, the organic light emitting diode according to the present exemplary embodiment includes a suppression layer 20 positioned in a first region on a substrate 10, an organic layer 30 positioned in a second region on a substrate 10, and the suppression layer. And a passivation layer 40 that exposes the 20 and selectively covers the organic layer 30. Here, the second region is a region where the organic light emitting element is formed, and the first region is a peripheral region of the second region where the organic light emitting element is formed.

The selective formation method of the encapsulation film according to the present invention is characterized in that a protective film such as a parylene thin film can be deposited on a desired portion simply and inexpensively by treating the inhibitor on the surface of the substrate for the selective formation of the encapsulation film. . To this end, the present invention provides a metal compound solution to be used as an inhibitor system.

The inhibitor system is a solution containing iron ions (Fe ²⁺ or Fe ³⁺ ) that characterizes the inhibitor regardless of the oxidation state of iron and also contains solutions containing iron ions regardless of the corresponding anions of iron ions. It consists of. In addition, the inhibitor system is configured using a mixed solvent of water and alcohols and water and a polar solvent, it is preferable to use in the concentration range of 0.1 ~ 30%. By using the above-described concentration range of 0.1 to 30%, particle problems that shorten the life of the device can be avoided.

The substrate 10 may be implemented as a substrate made of transparent glass or flexible plastic. In addition, a buffer layer may be formed on an upper surface of the substrate 10.

The organic layer 30 may be a low molecular or high molecular organic layer. In the case of using a low molecular weight organic layer, the organic layer 30 may be formed by stacking a single or complex structure such as a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, an electron injection layer, and the like as a usable organic material. Phthalocyanine (CuPc), tris-8-hydroxyquinoline aluminum (Alq3) and the like can be applied. The low molecular organic layer described above is implemented by the method of vacuum deposition. In the case of using the polymer organic layer, it may be formed by laminating a hole transport layer and an organic light emitting layer. Screen printing or inkjet printing may be performed using PEDOT, PPV (Poly-Phenylenevinylene), and polyfluorene (Polyfluorene) materials. It can be implemented in a method or the like.

The passivation layer 40 is made of parylene polymer. Parylene refers to a polymer belonging to a poly-para-xylylene system, and has excellent water resistance, heat resistance, and chemical resistance, and has excellent transmittance and refractive index. Moreover, the problem which the conventional silicon nitride and silicon oxynitride has is solved, and it is excellent in flexibility, and can exhibit the outstanding function as an encapsulation film of a flexible organic light emitting element. As the parylene polymer, any of parylene N, parylene D, and parylene C may be used.

On the other hand, the substrate 10 may be implemented as a thin film transistor (TFT) array substrate having an organic field effect transistor (see FIG. 5) for controlling the driving of the organic layer 30, in which case the above-described organic light emitting device The OLED may be implemented as an active type organic light emitting device instead of a passive type organic light emitting device.

2A to 2C are cross-sectional views illustrating a method for selectively forming an encapsulation film according to a preferred embodiment of the present invention.

First, as shown in FIG. 2A, the lower electrode or the first electrode 31 is formed on both sides of the substrate 10, for example, a plastic substrate, and then the inhibitor 20 is treated by dipping the substrate 10 in a 10% iron chloride solution. To perform. Thereafter, the inhibitor 20 treated portion is dried using nitrogen.

The first electrode 31 is formed by coating a transparent electrode such as ITO on the substrate 10. In addition, the inhibitor 20 is treated by dipping or printing the inhibitor on a portion without the organic light emitting device, that is, a portion of the first region on the substrate that does not require encapsulation.

Next, as shown in FIG. 2B, the hole injection layer 32 and the hole transport layer are sequentially formed on the first electrode 31. As the hole injection layer 32, 4,4'4 ''-tris (N, -3 (3-methylphenyl) -N-phenylamino) triphenyl amine) (MTDATA) having a thickness of 30 nm may be used. N, N'-bis- [1-naphthyl- (N, N-dipheny-1,1-biphenyl-4,4-diamine)] (NPB) having a thickness of 30 nm may be used. Subsequently, Alq _{3 (5)} having a thickness of 60 nm is vacuum deposited to form a green light emitting layer 33. After vacuum depositing LiF having a thickness of 1 to 2 nm on the formed laminated structure to form an electron transport layer and an electron injection layer 34, aluminum (Al) having a thickness of 100 nm is vacuum deposited to form a back electrode or a first electrode. 2 electrodes 35 are formed.

The first electrode 31 functions as an anode electrode and the second electrode 35 functions as a cathode electrode. Of course, the functions of the first electrode 31 and the second electrode 35 may be reversed. In addition, the first electrode 31 may be implemented as a transparent electrode or a reflective electrode, and when used as a transparent electrode, may be implemented as ITO, IZO, ZnO, or In ₂ O ₃ , and when used as a reflective electrode, Ag may be used. , Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, and a compound thereof for forming a transparent electrode such as a reflective film and ITO, IZO, ZnO or In ₂ O ₃ formed on the reflective film Can be implemented. In addition, the second electrode 35 may be implemented as a transparent electrode or a reflective electrode. When the transparent electrode is used as the transparent electrode, the second electrode 35 is used as a cathode and a metal having a small work function, that is, Li and Ca. , A film in which LiF / Ca, LiF / Al, Ag, Mg, and compounds thereof are deposited toward the light emitting layer 33, and a material for forming a transparent electrode such as ITO, IZO, ZnO, or In ₂ O ₃ on the film When used as a reflective electrode, it may be implemented with Li, Ca, LiF / Ca, LiF / Al, Ag, Mg, and compounds thereof.

Next, as shown in FIG. 2C, the protective film 40 of the parylene polymer thin film is formed on the second electrode 35 to encapsulate the organic light emitting device. The parylene polymer thin film may be deposited through a deposition process using various conventional deposition equipment.

According to the above configuration, the parylene protective film 40 is selectively formed only on the organic light emitting element. In addition, the parylene passivation layer 40 can be precisely implemented without the peeling phenomenon observed at its edge.

3 is a graph showing a change in luminance-voltage characteristic of an organic light emitting device manufactured by a method of selectively forming an encapsulation film according to an embodiment of the present invention.

As can be seen in Figure 3, the luminance of the organic light emitting device having an encapsulation film according to an embodiment of the present invention, and a general organic light emitting device having the same laminated structure as the organic light emitting device of the present invention, but does not include an encapsulation film Comparing the brightness-voltage characteristic, it is found that the curve B of the organic light emitting diode of the present invention operates stably for a wider range of voltage than the curve A of the organic light emitting diode of the comparative example. Can be.

4 is a graph showing the lifespan of the organic light emitting device manufactured by the method for selectively forming an encapsulation film according to an embodiment of the present invention.

An organic light emitting device having an encapsulation film (parylene thin film) formed by a selective deposition method of the present invention on a polyethylene (PET) film as a substrate and a general organic light emitting device were manufactured, and their lifetimes were compared and measured. . As can be seen in Figure 4, it can be seen that the curve (D) of the organic light emitting device according to the present invention maintains the relative brightness / brightness for a long time than the curve (C) of the general organic light emitting device according to the comparative example. As such, it can be seen that the lifespan of the organic light emitting device according to the present invention is significantly longer than that of the organic light emitting device according to the comparative example.

5 is a cross-sectional view illustrating an organic thin film transistor manufactured using a selective deposition method of an encapsulation film according to an embodiment of the present invention.

Referring to FIG. 5, the organic thin film transistor according to the present exemplary embodiment includes a suppression layer 60 positioned in a first region on a substrate 50, a gate electrode 72 positioned in a second region on a substrate 50, and a source. The organic semiconductor layer 78 by exposing the drain electrode 76, the organic semiconductor layer 78, the insulating layer 74 positioned between the organic semiconductor layer 78 and the gate electrode 72, and the suppression layer 60. ) Is optionally covered with a protective film 80. Here, the second region is a region where the organic field effect thin film transistor is formed, and the first region is a peripheral region of the second region where the organic field effect thin film transistor is formed.

In the manufacturing process of the organic thin film transistor according to the present embodiment, by treating the inhibitor on the surface of the substrate and forming the organic thin film transistor, a protective film such as a parylene thin film can be selectively deposited on a desired portion simply and inexpensively. do.

The above-described passivation layer 80 is implemented by a method for selectively forming an encapsulation film according to the present invention, and a description of the inhibitor system according to the present invention is directed to the method for selectively forming an encapsulation film described with reference to FIGS. 2A to 2C. Replace with the detailed description. The description of the substrate 50 and the suppression layer 60 is replaced with the description of the organic light emitting device mentioned with reference to FIG. 1. As other organic semiconductor configurations, various existing configurations may be applied.

A method for selectively forming an encapsulation film of the present invention relates to a system for selectively forming a polymer protective film on an organic light emitting device or an organic thin film transistor formed on a transparent substrate, and applying an inhibitor to a specific portion of the substrate before fabricating the device. It is a system that selectively forms a protective film on the surface of an organic light emitting device that requires a polymer protective film by inhibiting polymer formation by treating. According to the present invention, an optional parylene protective film can protect an organic light emitting device, an organic thin film transistor, and the like from oxygen and moisture, and can provide a process method that can reduce process complexity and reduce manufacturing cost. have.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the art that various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

As described above, the parylene thin film selectively deposited using the inhibitor according to the present invention is applicable to the encapsulation of the organic light emitting device and the organic field effect transistor, and has the following effects.

First, selective deposition of a parylene thin film using an inhibitor can obtain an organic thin film (protective film / parylene thin film) without peeling and damaging the applied sample without performing an additional process such as a separate etching.

Second, the selectively deposited parylene thin film has a high adhesion with the organic light emitting device, and because the sublimed gas is exposed to the surface in a vacuum state to the surface is deposited pinhole (pinhole) to the portion that can not be coated by liquid coating It can be coated perfectly without.

Third, by applying the inhibitor, it is possible to deposit a fine pattern of parylene thin film using a method such as dipping or printing.

Fourth, the selectively deposited parylene thin film has excellent resistance to temperature, humidity, and chemicals, and is applicable to encapsulation of organic light emitting devices that are vulnerable to moisture and oxygen, and to encapsulation of field effect transistors using organic materials. There is an advantage that can be applied to.

Claims (13)

Treating the substrate with an inhibitor; Forming a device having an organic material layer on the substrate; And And forming a protective film selectively covering the device by the action of the inhibitor. The method of claim 1, wherein the protective film is a parylene thin film. [4] The selective formation of an encapsulation film according to claim 1 or 2, wherein the inhibitor is formed of a solution containing iron ions, and the solvent of the solution is an alcohol or a mixed solvent of water and a polar solvent. Way. The method of claim 1, wherein treating the substrate with an inhibitor is performed after forming the lower electrode of the device on the substrate. The method of claim 3, wherein treating the substrate with an inhibitor comprises dipping or printing the substrate using a solution containing iron ions having a concentration of 0.1 to 30%. . A suppression layer located in the first region on the substrate; A first electrode, an organic layer, and a second electrode positioned in a second region on the substrate and having a stacked structure; And a passivation layer exposing the suppression layer and selectively covering the first electrode, the organic layer, and the second electrode. 7. The organic light emitting device of claim 6, wherein the suppression layer contains iron ions. The organic light emitting device according to claim 6 or 7, wherein the protective film is a parylene thin film. The organic light emitting device of claim 8, further comprising an organic field effect transistor positioned on the substrate to control driving of the organic layer. The organic light emitting device of claim 9, wherein the passivation layer covers the organic field effect transistor. A suppression layer located in the first region on the substrate; A gate electrode, a source / drain electrode, and an organic semiconductor layer positioned in the second region on the substrate; And a passivation layer exposing the suppression layer and selectively covering the gate electrode, the source / drain electrode, and the organic semiconductor layer. The organic thin film transistor according to claim 11, wherein the suppression layer contains iron ions. The organic thin film transistor according to claim 11 or 12, wherein the protective film is a parylene thin film.

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