KR102206329B1 - Organic electro-luminescent device and method of fabricating the same - Google Patents

Abstract

The present invention provides a first substrate in which a display area having a plurality of pixel areas is defined; A first electrode formed for each pixel area; A bank formed to overlap an edge of the first electrode and surround each pixel region, and has a double-layer structure of a lower layer having a hydrophilic property and an upper layer having a hydrophobic property; An organic light emitting layer formed on the first electrode in the bank; An organic light-emitting device including a second electrode formed on the organic light-emitting layer and on the entire surface of the display area, and a method of manufacturing the same are provided.

Description

Organic electro-luminescent device and method of fabricating the same}

The present invention relates to an organic electro-luminescent device, and in particular, an organic electro-luminescent device that has a double structure bank to improve spreading characteristics when forming a liquid organic light-emitting layer and to suppress spot defects And to a method of manufacturing the same.

An organic light emitting device, one of the flat panel displays (FPD), has high luminance and low operating voltage characteristics. In addition, since it is a self-luminous type that emits light by itself, it has a large contrast ratio, can implement an ultra-thin display, and it is easy to implement moving images with a response time of several microseconds (µs), and there is no limit on the viewing angle, and is stable even at low temperatures. And, since it is driven with a low voltage of 5V to 15V DC, it is easy to manufacture and design a driving circuit.

Accordingly, organic light emitting devices having the above-described advantages are recently used in various IT devices such as TVs, monitors, and mobile phones.

Hereinafter, the basic structure of the organic light emitting device will be described in more detail.

The organic light emitting diode is largely composed of an array element and an organic light emitting diode. The array element includes a switching thin film transistor connected to a gate and a data line, and a driving thin film transistor connected to the organic light emitting diode, and the organic light emitting diode includes a first electrode, an organic light emitting layer, and a second electrode connected to the driving thin film transistor. It consists of an electrode.

The organic light emitting device having such a configuration displays an image by emitting light generated from the organic light emitting layer toward the first electrode or the second electrode. Considering the aperture ratio, etc., in recent years, it is usually directed toward the second electrode. It is manufactured in a top emission method that displays an image using the emitted light.

On the other hand, in such a general organic light emitting display device, the organic light emitting layer is usually formed by a thermal evaporation method using a shadow mask. In recent years, due to an increase in the size of the display device, the shadow mask is severely sagged, resulting in increased deposition defects. It is becoming increasingly difficult to apply to a substrate of an area, and in the case of thermal evaporation using a shadow mask, a shadow effect is generated, so it is difficult to manufacture an organic electroluminescent device having a high resolution of 250 PPI or more with current technology.

Therefore, a method of forming an organic light emitting layer has been proposed to replace the thermal evaporation process using a shadow mask for manufacturing a large area organic light emitting device.

The proposed method of forming an organic light-emitting layer is to spray or drop a liquid organic light-emitting material onto a region surrounded by a partition wall through an inkjet device or a nozzle coating device, and then cure it.

1A to 1B are cross-sectional views of a manufacturing process briefly showing a step of forming an organic emission layer by dropping a liquid organic emission material through a nozzle coating device.

In order to spray liquid organic light-emitting material for each pixel area through an inkjet device or dropping through a nozzle coating device, to prevent the liquid organic light-emitting material from flowing to the surroundings within each pixel area (P). Essentially, a bank having a shape surrounding each pixel region in which the first electrode 50 is formed is required.

Accordingly, as shown in FIG. 1A, prior to forming the organic emission layer (55 in FIG. 1B), banks 53 are preferentially formed along the boundary of each pixel region P.

At this time, the bank 53 contains a fluorine (F) component in the organic insulating material so as to have hydrophobic properties. In this way, imparting hydrophobic properties to the bank 53 is not sprayed at the center of the pixel area P surrounded by the bank due to an error of the equipment itself when the liquid organic light emitting material is sprayed or dropped. Even if a predetermined amount is sprayed, it flows down from the bank 53 and is located in each pixel area P, and furthermore, even when the injection amount of the liquid organic light emitting material is slightly excessive, the overflow to the top of the bank 53 is suppressed. It is for sake.

When it has a hydrophobic property, it has the property of repelling the liquid organic light-emitting material having hydrophilic properties. Therefore, the organic light-emitting material is not coated on the upper part of the bank 53, and only the area surrounded by the bank 53 is concentrated. I can.

On the other hand, in the bank 53 having such hydrophobic properties, an organic insulating material mixed with fluorine (F) having hydrophobic properties is applied on the entire surface of the substrate 10, and a mask process including exposure and development processes using an exposure mask is performed. It is formed by doing.

Thereafter, as shown in FIG. 1B, the head of the inkjet device or the nozzle of the nozzle coating device 98 is positioned in each pixel area P surrounded by the bank 53 to spray or drop a liquid organic light emitting material. Then, the organic light-emitting material is filled in each pixel area P, and the organic light-emitting layer 55 is formed by performing heat treatment in this state to dry and cure.

However, when the organic emission layer 55 is formed as described above, the fluorine residue 54 remains in each pixel area P when the bank 53 is formed, so that when the liquid organic emission material is sprayed or dropped, each By interfering with the spreading characteristic in the pixel region P, the size of the pixel region P in each pixel region P is not sufficient, and Fig. 2 (a defect in which an organic light emitting layer is not formed around the bank to which the conventional hydrophobic property is given) As shown in the picture showing the state), the organic light-emitting layer is not formed around the bank or has a thinner thickness compared to other areas, resulting in uneven defects or deterioration at a high speed due to the difference in thickness. As a result, there has been a problem of shortening the life of the organic light emitting device.

The present invention was conceived to solve the above problem, and the present invention suppresses the fluorine residue from remaining in each pixel region P when a bank having hydrophobic properties is formed, thereby reducing spot defects, and furthermore, an organic emission layer around the bank. It is an object of the present invention to provide an organic electroluminescent device and a method of manufacturing the same, which is not formed or has a thin thickness and can suppress the phenomenon of being formed and improve the life of the device.

In the present invention, the step of forming a driving thin film transistor including a gate electrode and a source and drain electrode for each of the first and second pixel regions on a first substrate on which a display region having first and second pixel regions is defined, and , Forming a protective layer covering the driving thin film transistor, forming a first electrode over the protective layer, in contact with the drain electrode for each of the first and second pixel regions, and the first electrode Forming a bank having a double-layer structure of a lower layer having a hydrophilic property and an upper layer having a hydrophobic property in a form that overlaps an edge of and surrounds each of the first and second pixel regions, and the bank exposed by the bank Forming an organic light-emitting layer by spraying or dropping a liquid organic light-emitting material over the first electrode, and forming a second electrode over the display area over the organic light-emitting layer, wherein the lower layer Made of mid or acrylic, the upper layer contains a fluorine (F) component, the lower layer and the upper layer have photosensitive characteristics and phase separation characteristics, the protective layer is made of photoacrylic, the protective layer and the bank are different It is made of a material, the first electrode is located inside the drain electrode of the protective layer, and the lower layer is located above the first electrode, and the lower layer is inside the drain electrode of the protective layer exposed. The step of forming a bank that is filled and has a double-layered structure may include forming a bank material layer by coating a liquid material in which the polymer material and the low molecular material are mixed on the first electrode, and the bank material layer An organic electroluminescent device comprising the step of performing heat treatment for the polymer material to form a bank layer forming a double layer structure of a lower layer made of the low molecular material and an upper layer made of the polymer material by moving the low-molecular material downward. It provides a method of manufacturing.

In this case, the lower layer having hydrophilic properties is made of a hydrophilic polymer material having a molecular weight of 15,000 or more, and the upper layer having hydrophobic properties is characterized in that it is made of a hydrophobic low-molecular material having a molecular weight of less than 10,000, and having the double layer structure. The step of forming the bank further includes the step of patterning by performing exposure and development on the bank layer forming the double layer structure, and the low molecular weight material is characterized in that it contains 1 to 10 w% of the fluorine (F).

In addition, the heat treatment is performed by a soft baking process, and the bank material layer is dried and hardened by the heat treatment, and the movement of molecules inside the bank material layer is activated by the heat treatment during the drying process. , By the movement of the molecules, the polymer material having a molecular weight of 15,000 or more moves downward in the bank material layer, and the low molecular material material having a molecular weight less than 10,000 moves upward in the bank material layer. It is characterized by being.

In addition, a force to attract the liquid organic light-emitting material acts on the side of the lower layer, and the liquid organic light-emitting material comes into contact with the side of the lower layer. In the step of forming the organic light-emitting layer, the liquid It is characterized in that the cured organic light-emitting layer is formed by further comprising drying and curing the organic light-emitting material of, removing solvent and moisture in the liquid organic light-emitting material.

In addition, the bank overlaps an edge of the first electrode positioned in the first pixel region, and the bank is positioned above the source electrode of the second pixel region positioned adjacent to the first pixel region, The driving thin film transistor further includes an oxide semiconductor layer over the gate electrode, and an etch stopper partially overlapping with the oxide semiconductor layer is positioned over the oxide semiconductor layer.

The organic electroluminescent device according to the present invention has a double-layer structure in which the bank has a lower layer having a hydrophilic property and an upper layer having a hydrophobic property, and after patterning the bank, the residue of the hydrophobic material is almost on the top of the first electrode. When spraying or dropping a liquid organic light-emitting material in each pixel area surrounded by banks, the spreading property is excellent, and a lower layer having hydrophilic properties is provided, thereby generating a force that attracts the organic light-emitting material. At the same time, it is possible to achieve an effect that the organic light-emitting material is completely filled to the periphery adjacent to the bank, that is, to the edge of the pixel area.

Furthermore, since the liquid organic light-emitting material is formed to have a uniform thickness in each pixel area by improving the spreading characteristics, deterioration is suppressed and the lifespan is improved.

1A to 1B are cross-sectional views of a manufacturing process briefly showing a step of forming an organic emission layer by dropping a liquid organic emission material through a nozzle coating device.
2 is a photograph showing a defect state in which an organic emission layer is not formed around a bank to which a conventional hydrophobic property is provided.
3 is a circuit diagram of one pixel area of an organic light emitting diode.
4 is a cross-sectional view of a portion of a display area of an organic light emitting diode according to an exemplary embodiment of the present invention.
5 is a cross-sectional view of a driving thin film transistor in an organic light emitting device according to a modified example of the embodiment of the present invention.
6 is a cross-sectional view of a driving thin film transistor in an organic light emitting device according to another modification of the embodiment of the present invention.
7A to 7H are cross-sectional views in steps of manufacturing an organic light emitting diode according to an embodiment of the present invention.
8A to 8E are cross-sectional views in steps of manufacturing an organic light emitting diode according to a modified example of the embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

First, the configuration and operation of the organic light emitting device will be briefly described with reference to FIG. 3, which is a circuit diagram of one pixel area of the organic light emitting device.

As shown, in each pixel region P of the organic light emitting device, a switching thin film transistor (STr), a driving thin film transistor (DTr), a storage capacitor (StgC), and an organic light emitting diode (E) Is provided.

That is, the gate wiring GL is formed in the first direction, and the data wiring DL is formed in a second direction crossing the first direction, thereby being surrounded by the gate wiring GL and the data wiring DL. A pixel area P defined as a region is provided, and a power line PL for applying a power voltage is formed to be spaced apart from the data line DL.

In addition, a switching thin film transistor STr is formed at a portion where the data line DL and the gate line GL intersect, and a driving thin film transistor DTr electrically connected to the switching thin film transistor STr is formed. have.

The first electrode, which is one terminal of the organic light emitting diode E, is connected to the drain electrode of the driving thin film transistor DTr, and the second electrode, which is the other terminal, is grounded. In this case, the power voltage transmitted through the power wiring PL is transmitted to the organic light emitting diode E through the driving thin transistor DTr. In addition, a storage capacitor StgC is formed between the gate electrode and the source electrode of the driving thin film transistor DTr.

Therefore, when a signal is applied through the gate line GL, the switching thin film transistor STr is turned on, and the signal of the data line DL is transmitted to the gate electrode of the driving thin film transistor DTr to be driven. Since the thin film transistor DTr is turned on, light is output through the organic light emitting diode E.

At this time, when the driving thin film transistor DTr is turned on, the level of the current flowing from the power wiring PL to the organic light emitting diode E is determined, and thus the organic light emitting diode E Is able to implement a gray scale, and the storage capacitor StgC serves to maintain a constant gate voltage of the driving thin film transistor DTr when the switching thin film transistor STr is off. By doing so, even if the switching thin film transistor STr is turned off, the level of the current flowing through the organic light emitting diode E can be kept constant until the next frame.

4 is a cross-sectional view of a portion of a display area of an organic light emitting diode according to an exemplary embodiment of the present invention. At this time, for convenience of explanation, the driving area DA is the area where the driving thin film transistor DTr is formed, and the area where the switching thin film transistor is formed in each pixel area P, although not shown in the drawing, is a switching area (not shown). It is defined as

As shown, the organic light emitting device 101 according to the embodiment of the present invention includes a driving and switching thin film transistor (DTr, not shown), a first substrate 110 on which an organic light emitting diode E is formed, and It is composed of a second substrate 170 for encapsulation. In this case, the second substrate 170 may be omitted by being replaced with an inorganic insulating film or an organic insulating film.

First, the configuration of the first substrate 110 including the driving and switching thin film transistor DTr (not shown) and the organic light emitting diode E will be described.

In the first substrate 110, the display area crosses each other to define a pixel area P, a gate line (not shown) and a data line (not shown) are formed, and the gate line (not shown) or the A power line (not shown) is formed parallel to the data line (not shown).

In addition, a switching thin film transistor (not shown) is connected to the gate line (not shown) and a data line (not shown) in each of the plurality of pixel areas P, and one of the switching thin film transistors (not shown) It is connected to the electrode and the power wiring (not shown), and a driving thin film transistor DTr is formed.

At this time, the driving thin film transistor DTr is spaced apart from each other on the gate electrode 115, the gate insulating film 118, the oxide semiconductor layer 120, the etch stopper 122, and the etch stopper 122, respectively. It is composed of a source electrode 133 and a drain electrode 136 in contact with the oxide semiconductor layer 120, and although not shown in the drawing, the switching thin film transistor (not shown) also has the same structure as the driving thin film transistor DTr. Is being achieved.

On the other hand, in the embodiment of the present invention, the driving and switching thin film transistor (DTr, not shown) is shown as an example in which the oxide semiconductor layer 120 is provided, respectively. As shown in a cross-sectional view of a driving thin film transistor in an organic light emitting device according to a modification of the example), the switching and driving thin film transistor (not shown, DTr) includes a gate electrode 213 and a gate insulating layer 218. And, a semiconductor layer 220 composed of an active layer 220a of pure amorphous silicon and an ohmic contact layer 220b of impurity amorphous silicon, and source and drain electrodes 233 and 236 spaced apart from each other on the semiconductor layer 220 It may be composed of.

The switching and driving thin film transistor (DTr, not shown) is shown to form a bottom gate structure in which the gate electrode (115 in Fig. 4, 213 in Fig. 5) is located at the bottom in the embodiment and the modified example. It is located at the lowermost portion and may form a top gate structure in which a gate electrode is formed.

That is, as shown in FIG. 6 (a cross-sectional view of a driving thin film transistor in an organic light emitting device according to another modified example of the present invention), the switching and driving thin film transistor (not shown, DTr) is 1 The semiconductor layer 313 of polysilicon may be provided on the lowermost portion of the substrate 210 to have a top gate structure.

In this case, the switching and driving thin film transistor (DTr) is a semiconductor layer 313 comprising an active region 313a of pure polysilicon and source and drain regions 313b of polysilicon doped with impurities on both sides thereof. And, an interlayer insulating layer 323 having a gate insulating layer 316, a gate electrode 320 formed to overlap the active region 313a, and a semiconductor layer contact hole 325 exposing the source and drain regions 313b. ), and source and drain electrodes 333 and 336 formed to be in contact with the source and drain regions 313b and spaced apart from each other through the semiconductor layer contact hole 325, respectively.

When the driving and switching thin film transistor (DTr, not shown) forms a top gate structure, an interlayer insulating layer 323 is further provided compared to the bottom gate structure, and a gate wiring (not shown) is provided on the gate insulating layer 316. In addition, a data line (not shown) is formed on the interlayer insulating layer 323.

Meanwhile, referring to FIG. 4, a protective layer 140 having a drain contact hole 143 exposing the drain electrode 136 of the driving thin film transistor DTr over the driving and switching thin film transistor DTr (not shown). ) Is formed. At this time, the protective layer 140 is made of an organic insulating material, for example, photoacrylic so as to achieve a flat surface.

Next, the first electrode 150 is formed for each pixel region P in contact with the drain electrode 136 of the driving thin film transistor DTr through the drain contact hole 143 over the protective layer 140. have.

In this case, the first electrode 150 is made of a transparent conductive material having a work function value of about 4.8 eV to 5.2 eV, for example, indium-tin-oxide (ITO), which has a relatively large work function value. Plays a role.

On the other hand, when the first electrode 147 is made of indium-tin-oxide (ITO), which is a transparent conductive material having a large work function value, light emission from the top of the organic light emitting diode (E) when operating in the top emission mode In order to increase efficiency, a reflective layer (not shown) made of any one of aluminum (Al) and aluminum alloy (AlNd), which is a metal material having excellent reflectivity, may be further provided under the first electrode 150.

When such a reflective layer (not shown) is provided under the first electrode 150, light emitted from the organic light emitting layer 155 formed on the first electrode 150 is transmitted through the reflective layer (not shown). By reflecting and reflecting upward, it has the effect of increasing the efficiency of use of the emitted light and finally improving the luminance characteristics.

In addition, as the most characteristic of the organic light emitting diode 101 according to the exemplary embodiment of the present invention, a border of the first electrode 150 and a border of each pixel area P above the first electrode 150 A bank 153 is formed overlapping and exposing the central portion of the first electrode 150.

At this time, the bank 153 is characterized by forming a double layer structure. In the bank 153 constituting such a double-layer structure, the lower layer 153a has a hydrophilic property, and the upper layer 153b is made of a material having a hydrophobic property.

The organic light emitting device 101 according to the embodiment of the present invention has a double-layer structure in which the bank 153 has a lower layer 153a having hydrophilic properties and an upper layer 153b having hydrophobic properties, as described above. After 153 is formed by patterning, there is almost no residue of hydrophobic material on the top of the first electrode 150, so it spreads during spraying or dropping of a liquid organic light-emitting material in each pixel area P surrounded by the bank 153 The characteristics become excellent.

In addition, since the lower layer 153a having hydrophilic properties is provided, a force to attract the organic light-emitting material is generated, thereby further improving the spreading characteristics, and at the same time, organic light emission to the periphery adjacent to the bank 153, that is, to the edge of the pixel area P. The effect of completely filling the material can be achieved.

Next, an organic emission layer 155 that emits red, green, and blue light is formed on the first electrode 150 for each pixel area P surrounded by the bank 153 having the double-layer structure.

The organic light emitting layer 155 is characterized by being formed by spraying or dropping a liquid organic light emitting material through an inkjet device or a nozzle coating device, and then curing it.

The organic emission layer 155 has a uniform thickness with almost no thickness deviation in the entire area surrounded by the banks 153 in each pixel area P by the bank 153 having a double layer structure, which is a characteristic configuration of the present invention. It is characterized by being formed.

Meanwhile, in the drawings, the organic emission layer 155 is shown to be composed of a single layer made of only an organic emission material, but may be formed in a multilayer structure in order to increase luminous efficiency.

When the organic emission layer 155 has a multilayer structure, a hole injection layer, a hole transporting layer, and an organic layer are sequentially formed from the top of the first electrode 150 serving as the anode electrode. It may be formed in a five-layer structure of a light-emitting material layer, an electron transporting layer, and an electron injection layer, or a hole transporting layer or an organic light-emitting material layer. material layer), four-layer structure of electron transporting layer and electron injection layer, hole transporting layer, organic light emitting material layer, electron transporting layer It may be formed in a three-layer structure of.

Meanwhile, a second electrode 160 is formed on the organic emission layer 155 on the entire surface of the display area. In this case, the second electrode 160 is a metal material having a relatively low work function value, for example, aluminum (Al), aluminum alloy (AlNd), silver (Ag), magnesium (Mg), gold (Au), aluminum magnesium alloy. It is composed of one of (AlMg) and serves as a cathode electrode.

In this case, the first electrode 150, the organic emission layer 155, and the second electrode 160 form an organic light emitting diode (E).

Meanwhile, a second substrate 170 for encapsulation is provided corresponding to the first substrate 110 of the organic light emitting device 101 according to the embodiment of the present invention having the above-described configuration.

The first substrate 110 and the second substrate 170 are provided with an adhesive (not shown) made of a sealant or frit along the edges thereof, and the first substrate 110 and the second substrate 170 are provided with the adhesive (not shown). The second substrate 170 is attached to each other to maintain the panel state.

In this case, the first substrate 110 and the second substrate 170 spaced apart from each other may have a vacuum state or may have an inert gas atmosphere by being filled with an inert gas.

The second substrate 170 for encapsulation may be made of plastic having a flexible characteristic, or may be made of a glass substrate.

Meanwhile, the organic light emitting device 101 according to the above-described embodiment shows that the second substrate 170 for encapsulation is provided in a form facing and spaced apart from the first substrate 110, but as a modified example The second substrate 170 may be configured to contact the second electrode 160 provided on the uppermost layer of the first substrate 110 in the form of a film including an adhesive layer.

In addition, as another modified example according to the embodiment of the present invention, an organic insulating film (not shown) or an inorganic insulating film (not shown) may be further provided on the second electrode 160 to form a capping film, and the organic insulating film (Not shown) or the inorganic insulating film 162 may itself be used as an encapsulation film (not shown), and in this case, the second substrate 170 may be omitted.

Hereinafter, a method of manufacturing an organic light emitting diode according to an embodiment of the present invention having the above-described configuration will be described. At this time, the organic light emitting device according to the embodiment of the present invention is characterized in the configuration of the bank 153, and is manufactured by a general method until the steps of forming the switching and driving thin film transistors, so the description thereof will be simplified, and the double layer The step of forming the bank having the structure will be mainly described in detail.

7A to 7H are cross-sectional views of manufacturing steps of an organic light emitting device according to an exemplary embodiment of the present invention.

First, as shown in FIG. 7A, a gate wiring (not shown) and a date wiring (not shown) crossing each other by performing a general method on a first substrate 110 made of a transparent material, and the data wiring (not shown) ) And a switching thin film transistor (not shown) connected to the gate and data line (not shown) in a switching area (not shown), and at the same time in the driving area DA. A driving thin film transistor DTr connected to the switching thin film transistor (not shown) and a power wiring (not shown) is formed.

At this time, the switching and driving thin film transistor (not shown, DTr) includes an oxide semiconductor layer 120 or a semiconductor layer (220 in FIG. 5) composed of an active layer of amorphous silicon and an ohmic contact layer of impurity amorphous silicon. Thus, the gate electrode 115 may be formed in a bottom gate type provided at the bottom, or a semiconductor layer of polysilicon (320 in FIG. 6 is the lowest surface) by providing a semiconductor layer of polysilicon (320 in FIG. 6). It may be formed as a top gate type formed in the.

In the drawing, as an example, the switching and driving thin film transistor (not shown, DTr) is formed in a bottom gate type including the oxide semiconductor layer 120 as an example.

Next, a protective layer 140 having a flat surface is formed by applying an organic insulating material, for example, photoacrylic, on the switching and driving thin film transistor (DTr, not shown), and patterning is performed by performing a mask process thereon. A drain contact hole 143 exposing the drain electrode 136 of the thin film transistor DTr is formed.

Thereafter, on the protective layer 140 having the drain contact hole 143, a transparent conductive material having a relatively large work function value, for example, indium-tin-oxide (ITO) is deposited, or a metal material having excellent reflectivity. After first depositing aluminum (Al) or aluminum alloy (AlNd), the indium-tin-oxide (ITO) is deposited on the top thereof, and the drain contact hole for each pixel region (P) is patterned by performing a mask process thereon. A first electrode 150 in contact with the drain electrode 136 of the driving thin film transistor DTr is formed through 143. In this case, when the metal material having excellent reflectivity is deposited, a reflective layer (not shown) is further formed under the first electrode 150.

Next, as shown in FIG. 7B, on the protective layer 140 exposed between the first electrode 150 and the adjacent first electrode 150, a low molecular weight material having hydrophobic properties and a polymer having hydrophilic properties A substance having a photosensitive characteristic and a phase separation characteristic as a mixture of a substance having an appropriate content ratio, for example, a molecular weight of about tens to several thousand, preferably a low molecular weight substance containing a fluorine (F) component with a molecular weight of 10 or more and less than 10,000. In the case of a coating device 198, a liquid material in which a photosensitive polymer material such as polyimide or acrylic is mixed, preferably 15,000 or more and 1 million or less, is used as a spin coating device, a bar ( bar) The bank material layer 151 is formed by coating the entire surface using either a coating device or a slit coating device.

Next, as shown in FIG. 7C, a heat treatment is performed on the bank material layer (151 in FIG. 7B) to perform a soft baking process. The soft baking process through the heat treatment can be performed for tens to several hundred seconds in an oven or furnace having a temperature atmosphere of about 60°C to 100°C, or using a hot plate having a surface temperature of 60°C to 100°C. It is preferable to proceed for tens to several hundred seconds.

By this soft baking process, the bank material layer (151 in FIG. 7B) is dried and hardened, and the movement of molecules within the bank material layer (151 in FIG. 7B) is activated by the heat supplied during the drying process. Heavy molecules having a molecular weight of 1,000 or more move to the bottom of the bank material layer (151 in FIG. 7B), and relatively light molecules with a molecular weight of less than 10,000 move to the top in the bank material layer (151 in FIG. 7B). Moving phase separation occurs.

In the state in which the phase separation phenomenon occurs, solvent and moisture are volatilized and removed by heat supplied by heat treatment to the bank material layer (151 in FIG. 7B), and finally, the lower layer 152a made of a polymer material having hydrophilic properties. And, a bank layer 152 having a double-layer structure of an upper layer 152b made of a low molecular weight material having hydrophobic properties is formed.

Next, as shown in Fig. 7D, an exposure mask (not shown) having a reflective region and a transmissive region is positioned with respect to the bank layer (152 of Fig. 7C) having the double-layer structure, and the exposure mask (not shown) is used. After performing exposure, development using a developer is performed.

Since the bank layer (152 in FIG. 7C) itself has a photosensitive characteristic, and more precisely, a negative-type characteristic in which the lighted portion remains after development, the portion corresponding to the transmission area of the exposure mask (not shown) during exposure is A portion that does not react to the developer and corresponds to the blocking region of the exposure mask (not shown) is removed in response to the developer.

In this case, the bank layer (152 in FIG. 7C) having a double-layer structure, which is a characteristic configuration according to an embodiment of the present invention, is a lower layer (152a in FIG. 7C) in contact with or adjacent to the first electrode 150 is made of a polymer material. As a result, since there are almost no low-molecular substances containing fluorine (F) components, after they are removed in response to a developer, the residue of fluorine (F) components is completely removed without remaining on the surface of the first electrode 150. The amount of contrast becomes very weak.

The bank layer (152 in FIG. 7C) that is not removed by the development process and finally remains has a double-layer structure of a lower layer 153a having a hydrophilic property and an upper layer 153b having a hydrophobic property, and each pixel region P The bank 153 of a double-layer structure overlapping the edge of the first electrode 150 is formed in correspondence with the boundary of.

On the other hand, in the manufacturing method of the organic light emitting device according to the embodiment of the present invention, it is shown that the bank 153 having a double layer structure is formed using a material capable of phase separation, but as a modified example, a photosensitive material having hydrophilic properties The bank 153 having a double layer structure may be formed using a photosensitive material having hyperhydrophobic properties.

8A to 8F are cross-sectional views illustrating a step-by-step process of manufacturing an organic light-emitting device according to a modified example of the embodiment of the present invention, showing only the steps of forming a bank having a double layer structure. In this case, the switching and driving thin film transistors are omitted in the drawing, and only the first electrode 150 on the first substrate 110 is illustrated.

First, as shown in FIG. 8A, the first bank material layer is coated with a photosensitive material having hydrophilic properties, for example, polyimide or acrylic, on the entire surface of the first electrode 150 using a coating device (not shown). 451).

Thereafter, as shown in FIG. 8B, soft baking by heat treatment is performed on the first bank material layer (451 in FIG. 8A) to dry and cure to form a first bank layer 452 having hydrophilic properties. .

In this case, the photosensitive material having the hydrophilic property is characterized in that it does not matter the molecular weight. That is, even if the photosensitive material having the hydrophilic property is a polymer material or a low molecular material, there is no problem.

Next, as shown in FIG. 8C, by coating the first bank layer 452 with a photosensitive material having a hydrophobic property, for example, acrylic containing fluorine (F), using a coating device (not shown). A bank material layer 453 is formed.

Thereafter, as shown in FIG. 8D, the second bank material layer (453 in FIG. 8C) is soft baked by heat treatment to dry and cure to form the second bank layer 454.

In this case, the photosensitive material having the hydrophobic property is also characterized in that it does not matter to the molecular weight. That is, even if the photosensitive material having the hydrophobic property is a polymer material or a low molecular material, there is no problem.

The first bank layer 452 having the hydrophilic property has already been soft-baked and cured, and the photosensitive material having hydrophobic properties is coated on the top thereof, so even if the photosensitive material having the hydrophobic property is soft-baked, This is because molecules of the photosensitive material having hydrophobic properties cannot move into the already cured first bank layer 452.

Next, as shown in FIG. 8E, in the manufacturing method according to the embodiment of the present invention, for the first and second bank layers (452, 454 in FIG. 8D) sequentially stacked through two coating processes and a soft baking process. As mentioned above, the double layer structure of the lower layer 153a having the same hydrophilic properties and the upper layer 153b having hydrophobic properties as shown in FIG. 6D by performing exposure using an exposure mask and then performing a development process using a developer for patterning. A bank 153 having a can be formed.

Even by the method of forming the bank 153 according to this modification, the residue of the material having hydrophobic properties does not remain on the surface of the first electrode 150, and the spreading property of the organic light emitting material sprayed or dropped in a later step It is characterized by improvement.

Since the subsequent steps are the same as the manufacturing method according to the embodiment of the present invention, the manufacturing method according to the following modification is omitted.

Next, as shown in FIG. 7E, the liquid organic light-emitting material is prepared by using an inkjet device or a nozzle coating device 199 in correspondence to the first substrate 110 on which the bank 153 having the double-layer structure is formed. An organic light emitting material layer 154 is formed on the first electrode 150 by spraying or dropping corresponding to each pixel area P surrounded by the bank 153.

At this time, in the step of spraying or dropping the liquid organic light-emitting material, if the liquid organic light-emitting material is sprayed or dropped into each pixel area P, it is sprayed to the own error of the inkjet device or the nozzle coating device 199 Alternatively, even if the dropping position is biased and dropping is performed on the bank 153, since the upper layer 153b of the bank 153 has a hydrophobic characteristic, it flows into each pixel area P surrounded by the bank 153.

In addition, even if the amount of the liquid organic light-emitting material sprayed is slightly large, the upper layer 153b of the bank 153 has a hydrophobic property, and thus has a tendency to push out the organic light-emitting material, thereby preventing overflow.

Furthermore, since the lower layer 153a of the bank 153 has a hydrophilic property, the liquid organic light emission from the side of the lower layer 153a of the bank 153 within each pixel region P surrounded by each bank 153 A force for pulling the material acts to spread the liquid organic light-emitting material well on the surface of the first electrode 150 and further, to have a state in contact with the side of the lower layer 153a of the bank 153.

In this state, as shown in FIG. 7F, the organic light emitting layer 155 in a cured state can be formed by performing a drying and curing process on the organic light emitting material layer (154 in FIG. 7E) to remove solvent and moisture. have.

In this case, since the organic emission layer 155 is formed to contact the lower layer 155a of the bank 153, the spreading characteristic is lowered as in the prior art, thereby preventing a phenomenon that is not formed on the edge of the bank 153. It works.

Meanwhile, in the drawing, it is shown as an example that only the organic emission layer 153 having a single-layer structure is formed on the first electrode 150, but when the organic emission layer 153 is formed of multiple layers, the single-layer organic emission layer A hole injection layer (not shown) or a hole transport layer (not shown) under or above the organic emission layer 153 by performing the same method in which 153 is formed, or by performing a full deposition method in the display area. A hole transporting layer (not shown), an electron transporting layer (not shown), and an electron injection layer (not shown) may be selectively further formed.

Next, as shown in FIG. 7G, a metal material having a relatively low work function value above the organic emission layer 155, for example, aluminum (Al), aluminum alloy (AlNd), silver (Ag), magnesium (Mg), gold A first substrate for an organic light emitting device according to an embodiment of the present invention by mixing any one or two or more of (Au) and aluminum magnesium alloy (AlMg) and depositing it on the entire display area to form the second electrode 160 ( 110) is completed.

At this time, the first electrode 150, the organic emission layer 155, and the second electrode 160 sequentially stacked in each pixel region P by the above-described method form an organic light emitting diode E.

Next, as shown in FIG. 7H, a second substrate 170 is positioned opposite to each other for encapsulation of the organic light emitting diode E in correspondence with the first substrate 110, and the first substrate ( Between the first substrate 110 and the second substrate 170, a face seal (not shown) made of any one of a frit, an organic insulating material, and a polymer material, which is transparent and has adhesive properties, is placed on the front surface of the first substrate 110. After bonding the first substrate 110 and the second substrate 170 in a coated state, or forming a seal pattern (not shown) along the edge of the first substrate 110 in a vacuum or inert gas atmosphere By bonding the first and second substrates 110 and 170 together, an organic light emitting diode according to an embodiment of the present invention is completed.

On the other hand, by depositing or applying an inorganic insulating material or an organic insulating material on the second electrode 160 of the first substrate 110, or restarting an adhesive layer (not shown) to attach a film (not shown) to encapsulate When used as an ration film (not shown), the second substrate 170 may be omitted.

The present invention is not limited to the above-described embodiments and modifications, and various modifications may be made without departing from the scope of the present invention.

101: organic light emitting device 110: first substrate
115: gate electrode 118: gate insulating film
120: oxide semiconductor layer 122: etch stopper
133: source electrode 136: drain electrode
140: protective layer 143: drain contact hole
150: first electrode 153: bank
153a: lower layer (of bank) 153b: upper layer (of bank)
155: organic emission layer 160: second electrode
DA: Driving area DTr: Driving thin film transistor
P: pixel area

Claims (10)

Forming a driving thin film transistor including a gate electrode and a source and drain electrode for each of the first and second pixel regions on a first substrate on which a display region having first and second pixel regions is defined;
Forming a protective layer covering the driving thin film transistor;
Forming a first electrode over the protective layer and in contact with the drain electrode for each of the first and second pixel regions;
Forming a bank having a double-layer structure of a lower layer having a hydrophilic property and an upper layer having a hydrophobic property, overlapping with an edge of the first electrode and surrounding each of the first and second pixel regions;
Forming an organic light emitting layer by spraying or dropping a liquid organic light emitting material on the first electrode exposed by the bank;
Forming a second electrode over the organic emission layer on the entire surface of the display area
Including,
The lower layer is made of polyimide or acrylic, the upper layer contains 1 to 10 w% of fluorine (F) component, and the lower layer and the upper layer have a phase separation characteristic,
The protective layer is made of photoacrylic, the protective layer and the bank are made of different materials,
The first electrode and the lower layer are positioned above the first electrode in the protective layer where the drain electrode is exposed,
The lower layer is filled inside the protective layer to which the drain electrode is exposed,
Forming the bank having the double layer structure,
Forming a bank material layer by coating a liquid material in which a polymer material and a low molecular material are mixed on the first electrode;
A heat treatment is performed on the bank material layer so that the polymer material moves the low molecular weight material downward to form a bank layer forming a double layer structure of the lower layer made of the polymer material and the upper layer made of the low molecular material. And
The polymer material is made of hydrophilic having a molecular weight of 15,000 or more, and the low molecular material is a method of manufacturing an organic electroluminescent device made of hydrophobic having a molecular weight of less than 10,000.
delete The method of claim 1,
Forming the bank having the double layer structure,
Exposing and developing the bank layer forming the double-layer structure to pattern it
The method of manufacturing an organic light emitting device further comprising a.
delete The method of claim 1,
The heat treatment is performed by a soft baking process,
The bank material layer is dried and cured by the heat treatment,
The method of manufacturing an organic electroluminescent device, characterized in that the movement of molecules inside the bank material layer becomes active by the heat treatment during the drying process.
The method of claim 5,
By the movement of the molecules, the polymer material having a molecular weight of 15,000 or more moves downward in the bank material layer,
The method of manufacturing an organic electroluminescent device, characterized in that the low molecular weight material having a molecular weight of less than 10,000 moves upward in the bank material layer.
The method of claim 1,
At the side of the lower layer, a force to attract the liquid organic light-emitting material acts,
The method of manufacturing an organic light-emitting device, wherein the liquid organic light-emitting material contacts a side surface of the lower layer.
The method of claim 1,
In the step of forming the organic emission layer,
Further comprising drying and curing the liquid organic light emitting material,
A method of manufacturing an organic light-emitting device, characterized in that a cured organic light-emitting layer is formed by removing solvent and moisture in the liquid organic light-emitting material.
The method of claim 1,
The bank overlaps an edge of the first electrode positioned in the first pixel region,
The bank is a method of manufacturing an organic light emitting diode disposed above the source electrode of the second pixel area adjacent to the first pixel area.
The method of claim 1,
The driving thin film transistor further includes an oxide semiconductor layer over the gate electrode,
A method of manufacturing an organic electroluminescent device in which an etch stopper partially overlapping with the oxide semiconductor layer is positioned above the oxide semiconductor layer.

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