KR100342195B1 - Method for fabricating organic electroluminescent display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an organic light emitting display device, wherein a polymer organic material having a predetermined color (red, green, blue), a cathode forming metal, and a photoresist are sequentially formed on an upper surface of a substrate on which an anode is formed. The resist is patterned, and the patterned photoresist is used as a mask to dry-etch them from the cathode forming metal in order to pattern cathode electrodes and organic electroluminescent parts that generate light of a predetermined color in a portion where a pixel is to be formed.

Then, the thicknesses of the organic ELs for each color (red, green, blue) can be controlled to be the same, and the pixels can be separated cleanly.

Description

Manufacturing method of organic electroluminescent display device {Method for fabricating organic electroluminescent display device}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an organic light emitting display device. More particularly, an organic material having a predetermined color, a predetermined metal, and a photoresist are sequentially stacked on a substrate, and then the photoresist is patterned to maintain a predetermined color. The photoresist is left only in a predetermined pixel to leave the material, and the patterned photoresist is used as a mask to dry the metal to form a cathode electrode. The cathode is used as a mask to dry-etch the organic material to generate light of a predetermined color. The present invention relates to a method of manufacturing an organic electroluminescent display device for patterning an organic electroluminescent unit.

Preferably, the above-described method is a process applied when forming an organic light emitting display device using a polymer organic material.

CRT (Cathode Ray Tube), one of the commonly used display devices, is mainly used for monitors such as TVs, measuring devices, and information terminal devices.However, due to the weight and size of the CRT itself, Could not respond actively to the demand.

In order to replace the CRT, development of a flat panel display device having advantages such as light and small size and low power consumption is actively progressing, and the demand thereof is continuously increasing. Until now, the demand for liquid crystal display devices for displaying information using the electro-optical properties of liquid crystals among flat panel display devices has been the highest, and technology development has been focused on liquid crystal display devices.

However, since the liquid crystal display device is a light-receiving device that displays an image by adjusting the amount of light coming from the outside, driving is complicated and a separate light source, i.e., a backlight assembly, for irradiating light to the liquid crystal panel is absolutely necessary. There are many disadvantages in many aspects, including the realization of light and small size display and price competitiveness.

As a result, in recent years, the organic electroluminescence is a self-luminous device that is fast in response time, excellent in brightness, and simple in structure, which is advantageous in terms of cost competitiveness, and can easily realize light and small size reduction. The development of display devices is actively progressing. The organic electroluminescent device is attracting attention as a next-generation flat panel display device following the liquid crystal display device due to its various uses such as a backlight of a liquid crystal display device, a portable terminal, an automobile navigation system, a laptop computer, and a wall-mounted TV.

The organic light emitting display device forms an organic electroluminescent portion that emits light by itself between an anode electrode to which a positive power is applied and a cathode electrode to which a negative power is applied, and holes and cathode electrodes transferred from the anode electrode to the organic electroluminescent portion. The electrons transmitted to the organic electroluminescent unit are recombined to generate light of a predetermined color.

The organic electroluminescent unit that generates light by the flow of electric current can be formed using a low molecular organic material or a high molecular organic material. Since the low molecular organic material can be deposited, patterning of the organic electroluminescent part is relatively easy.

Therefore, in the case of an organic light emitting display device using a low molecular organic material, an inverted trapezoidal partition wall which forms an anode and separates between the organic light emitting units and the cathode electrodes to prevent a short circuit intersects with the anode electrodes. Stand up as much as possible. Subsequently, a shadow mask that opens only the pixels of the portion where the red, green, and blue organic material is to be deposited is adjacent to the substrate, and then a low molecular organic material is deposited on the substrate by a method such as evaporation, thereby providing the respective pixels. For example, red, green, and blue organic electroluminescent units are sequentially formed.

When organic electroluminescent units generating red, green, and blue colors are deposited on each pixel through the above process, an organic electroluminescent display device is manufactured by depositing a cathode forming metal on the entire surface to form a cathode electrode between partition walls.

On the other hand, the polymer organic material is not deposited and difficult to pattern.

For this reason, unlike when forming an organic electroluminescent unit by patterning a low molecular organic material, an organic electroluminescent unit is formed by spraying organic materials having a predetermined color on each pixel using an inkjet printing method.

In more detail, after installing an ink cartridge containing a predetermined color, for example, a red organic material in an inkjet print, moving the nozzle to inject the red organic material only to the pixels where the red organic material is to be formed. An electroluminescent part is formed.

Next, an ink cartridge containing a green organic material is mounted on an inkjet print, thereby spraying the green organic material only on the pixel where the green organic material is to be deposited to form a green organic electroluminescent unit. The blue organic electroluminescent portion is also formed in the same manner as the red and green organic electroluminescent portion.

Thereafter, a cathode electrode to apply negative power to the organic electroluminescent unit for each color is formed through a separate process.

However, some problems occur when the polymer organic material is coated by the inkjet printing method described above.

When the organic electroluminescent unit is formed by spraying a polymer organic material by inkjet printing, there is a problem in that the quality of the organic light emitting display device is deteriorated because the coating thickness of each polymer organic material is not uniformly controlled.

In addition, in the case of realizing colors using red, green, and blue polymer organic materials, nozzles of ink cartridges containing respective pixels to be applied to each color and polymer organic materials of any one of red, green, and blue colors are included. There is a problem in that it is difficult to align and the additional process for alignment is added, the process time is long and the price is increased.

Meanwhile, various polymer organic materials printed by inkjet printing are completely dried and mixed with polymer organic materials of different colors applied to adjacent pixels, so that it is difficult to cleanly separate colors between adjacent pixels. have.

Accordingly, an object of the present invention is to improve the image quality by controlling the thickness of the red, green, and blue organic materials in the same manner using a dry etching method, and by separating the pixels cleanly.

Another object of the present invention is to simplify the manufacturing process of the organic EL device.

Still other objects of the present invention will become more apparent from the following detailed description and the accompanying drawings.

1A to 1D are views for explaining a process of forming a red pixel according to the present invention;

2A to 2D are views for explaining a process of forming a green pixel according to the present invention;

3A to 3D illustrate a process of forming a blue pixel according to the present invention.

4 is a view showing a process of forming a protective film on the upper surface of the pixel for each color formed by the present invention,

5A to 5B are views for explaining a process of connecting pixels for each color with corresponding cathode side leads.

In order to achieve the above object, the present invention deposits a transparent metal material on the upper surface of the substrate which transmits light, thereby patterning a plurality of anode electrodes on the screen display area of the substrate, and anode side leads and cathodes on the outside of the screen display area. The side leads are patterned, an organic material having a predetermined color, a cathode electrode forming metal and a photoresist are sequentially formed on the substrate on which the anode electrodes are patterned, and the photoresist is patterned to use the patterned photoresist as a mask for the underlying film. The organic electroluminescent unit and the cathode electrodes are patterned by dry etching from the cathode forming metal to the organic material in order to generate light of a predetermined color on the anode electrodes positioned on the same line as the cathode side leads among the upper surfaces of the anode electrodes. The electroluminescent parts and the cathode electrodes A protective film is formed on the substrate to protect it from the mirror, and finally, contact holes are formed in a portion of the protective film where the cathode electrodes are formed to expose the cathode electrodes to the outside of the protective film, and the screen display area is crossed from a predetermined portion of the cathode-side leads. The metal for connection is deposited on the same line as the cathode-side leads so as to connect the cathode-side leads and the cathode electrodes.

Hereinafter, a method of manufacturing an organic light emitting display device according to the present invention will be described with reference to FIGS. 1 to 5.

First, by vacuum depositing a transparent metal, for example, ITO, on the upper surface of the substrate 110 that transmits light, and then patterning the ITO using photolithography and etching techniques, the substrate 110 as shown in FIG. 1D. The stripe-shaped anode electrodes 120 are spaced apart from each other by a predetermined distance in the screen display area 115 of FIG. The anode side leads 125 and the cathode side leads 145 are formed outside the screen display area 115.

Here, anode side leads 125 are formed integrally with the anode electrodes 120 at one end in the longitudinal direction of the anode electrodes 120, and cathode side leads at one side of the anode electrode 120 in the width direction thereof. The 145 is formed in a line, and one end of the cathode side leads 145 adjacent to the screen display area 115 is formed separately from the anode electrodes 120.

When the anode electrodes 120 and the anode and cathode side leads 125 and 145 are formed on the substrate 110, a red polymer organic material 130a may be formed on the substrate 110, for example, as shown in FIG. 1A. The cathode electrode forming metal 140a and the photoresist 150a are sequentially stacked.

Subsequently, a predetermined pixel to which the red polymer organic material 130a is to be patterned from the upper surfaces of the anode electrodes 120 by exposing and developing the photoresist 150a (hereinafter, referred to as “red pixel” for convenience of description). Only the photoresist 150 is left as shown in FIG. 1B.

Thereafter, the cathode electrode forming metal 140a is dried with chloride (Cl ₂ ) gas using the photoresist 150 remaining only on the portion where the red pixels 160R (see FIG. 1D) will be formed as a mask for the lower layer. Etch it. Then, as shown in FIG. 1C, the cathode gas forming metal 140a is selectively etched by selectively etching the cathode electrode forming metal 140a exposed by the chloride gas to the outside of the photoresist 150. Will remain. This becomes the cathode electrode 140.

When dry etching the cathode electrode forming metal 140a, a portion of the photoresist 150 is torn off due to a physical collision of chloride gas.

As such, when the cathode electrodes 140 are formed below the photoresist 150, the cathode 140 is used as a mask for the red polymer organic material 130a, and the red polymer organic material 130a is dry-etched to red. Red organic electroluminescent parts 130 are formed in a region to be the pixel 160R. In this case, the gas for dry etching the red polymer organic material 130a is oxygen (O ₂ ).

In more detail, when the substrate 110 on which the cathode electrode 140 is formed is injected into a process chamber (not shown) to inject oxygen gas, a red polymer in which oxygen gas is exposed to the outside of the cathode electrode 140. By selectively etching only the red polymer organic material 130a exposed to the outside of the cathode electrode 140 by reacting with the organic material 130a, the red light that generates red light by the flow of electric current in the lower portion of the cathode electrode 140 The organic electroluminescent unit 130 is patterned.

At this time, since the photoresist 150 is also a kind of organic material, it is etched by oxygen gas and completely removed.

The red pixels 160R described above may have a red organic electroluminescent unit 130 formed on a predetermined portion of the anode electrode 120 positioned on the same line as the cathode side leads 145 among the upper surfaces of the anode electrodes 120. , Refers to a portion in which the cathode electrode 140 is sequentially stacked.

When the red pixels 160R for generating red light are formed on a predetermined portion of the upper surface of the anode electrode 120 by the above-described method, green pixels 160G are formed next.

That is, as shown in FIG. 2A, the green polymer organic material 132a, the cathode electrode forming metal 142a, and the photoresist 152a are sequentially formed on the substrate 110 on which the red pixels 160R are patterned. do.

Subsequently, the photoresist 152a is exposed and developed so that a predetermined pixel to be formed next to, for example, red pixels 160R among the upper surfaces of the anode electrodes 120 (hereinafter referred to as "green pixel" for convenience of description). Only the photoresist 152 is left as shown in FIG. 2B.

Thereafter, the cathode electrode forming metal 142a is dry etched with chloride gas using the photoresist 152 remaining in the portion where the green pixels 160G (see FIG. 2D) will be formed as a mask for the lower layer. Then, as shown in FIG. 2C, the chloride gas reacts with the cathode electrode forming metal 142a to selectively etch the cathode electrode forming metal 142a exposed to the outside of the photoresist 152, thereby removing the photoresist 152. The cathode electrode forming metal 142a is left only at the bottom. The cathode electrode forming metal 142a remaining under the photoresist 152 becomes the cathode electrode 142.

As such, when the cathode electrodes 142 are formed below the photoresist 152, the green polymer organic material 132 is dry-etched using the cathode electrode 142 as a mask for the green polymer organic material 132a. As shown in FIG. 2D, green organic electroluminescent parts 132 for generating green light are formed under the cathode electrode 142. At this time, the gas for dry etching the green polymer organic material 132a is the same oxygen gas as the gas for etching the red polymer organic material 130a.

Here, when the substrate 110 on which the cathode electrode 142 is formed is introduced into a process chamber to inject oxygen gas, the oxygen gas reacts with the green polymer organic material 132a exposed to the outside of the cathode electrode 142 to form a cathode. The green organic electroluminescent unit 132 is patterned under the cathode electrode 142 by etching the green polymer organic material 132a exposed to the outside of the electrode 142. At this time, since the photoresist 152 is also a kind of organic material, it is etched by oxygen gas and completely removed.

Herein, the green pixels 160G described above may be formed on a predetermined portion of the anode electrodes 120 positioned on the same line as the cathode leads 145 among the upper surfaces of the anode electrodes 120. 132 and a portion in which the cathode electrode 142 is stacked in this order.

The process of forming the blue pixel 160B is illustrated in FIGS. 3A to 3D, and the process of forming the blue pixel 160B is the same as that of forming the red pixel 160R and the green pixel 160G. do.

Here, reference numeral 134a is a blue polymer organic material coated on the substrate 110, and 134 is a blue organic electroluminescent part formed on predetermined portions of the anode electrodes 120. In addition, 144a is a cathode forming metal deposited on the substrate 110, and 144 is formed on the upper surface of the blue organic electroluminescent unit 134 to apply negative power to the blue organic electroluminescent unit 134. Electrode.

On the other hand, 154a is a photoresist coated on the top surface of the cathode electrode forming metal 144a to pattern the cathode electrode forming metal 144a, and 154 is a patterned photoresist.

When the red pixels 160R, the green pixels 160G, and the blue pixels 160B are alternately formed on the upper surfaces of the anode electrodes 120, the organic light emitting units 130, 132, and 134 for each color vulnerable to moisture and oxygen are formed. In order to protect the and to prevent the oxidation of the cathode electrodes 140, 142, and 144 in the air, a protective film 170 is formed on the upper surface of the cathode electrodes 140, 142, and 144 as shown in FIG. 4.

As described above, when the passivation layer 170 is formed, as illustrated in FIG. 5A, the cathode electrodes 140, 142, and 144 formed on the same line as the cathode side leads 145 are electrically connected to the cathode side leads 145. Likewise, the contact hole 175 is formed by etching a predetermined portion of the passivation layer 170 corresponding to each of the cathode electrodes 140, 142, and 144.

Thereafter, a stripe-shaped opening is formed to expose the passivation layer 170 located on the same line as the cathode side leads 145 in the passivation layer 170, and the cathode side leads 145 in the passivation layer 170. The portions corresponding to the spaces between them are deposited on the passivation layer 170 by placing a mask (not shown) that closes the connection metal 180.

Then, as shown in FIG. 5B, the connecting metal 180 intersects the anode electrodes 120 at predetermined portions of the upper surface of the passivation layer 170 corresponding to the pixels 160R, 160G, and 160B for each color. As the deposition is performed, the contact hole 175 is filled, and the connection metal 180 is connected to the cathode side leads 145 and the cathode electrodes 140, 142, and 144 formed on the same line through the contact hole 175, and thus the cathode side is connected to the cathode side. The lead 145 and the plurality of cathode electrodes 140, 142, and 144 positioned on the same line are electrically connected to each other.

When the organic electroluminescent display device according to the present invention is manufactured by applying the method as described above, the thickness of the organic electroluminescent units for each color (red, green, blue) can be controlled to be equal, and between pixels. Since it can be separated cleanly there is an effect that can improve the image quality of the organic light emitting display device.

In addition, there is an effect that the productivity of the product can be improved by simplifying the manufacturing process of the organic EL device compared with the prior art.

Claims (5)

By depositing a transparent metal material on the upper surface of the substrate that transmits light, a plurality of anode electrodes are patterned in an area where the screen is displayed on the substrate, and anode leads and cathode leads are formed outside the area where the screen is displayed. Patterning; Stacking an organic material having a predetermined color, a cathode electrode forming metal, and a photoresist on the substrate on which the anode electrodes are patterned; After patterning the photoresist, the patterned photoresist is used as a mask for a lower layer, followed by dry etching from the cathode forming metal to the organic material having the predetermined color, and the cathode-side leads of the anode electrodes. Forming pixels by patterning an organic electroluminescent unit and cathode electrodes which generate light of a predetermined color on the anode electrodes positioned on the same line; Forming a protective film on the substrate on which the pixels are formed to protect the organic electroluminescent parts and the cathode electrodes from an external environment; Contact holes are formed in a portion of the passivation layer where the cathode electrodes are formed to expose the cathode electrodes to the outside of the passivation layer, and the same as the cathode side leads to cross the screen display area from a predetermined portion of the cathode side leads. And depositing a connection metal on a line to connect the cathode side leads and the cathode electrodes. The method of claim 1, wherein the pixel forming step Patterning the photoresist to leave the photoresist only at a predetermined position of the anode electrode located on the same line as the cathode side leads among the upper surfaces of the anode electrodes; Dry etching the cathode forming metal with a predetermined gas using the patterned photoresist as a mask for the cathode forming metal to form the cathode on the bottom surface of the patterned photoresist; Dry etching the organic material having the predetermined color with a predetermined gas by using the cathode as a mask for the organic material having the predetermined color to form the organic electroluminescent unit for generating light of a predetermined color under the cathode electrode The manufacturing method of the organic electroluminescent display element characterized by the above-mentioned. The method of claim 2, wherein red, green, and blue pixels are formed on the substrate, wherein the organic material having any one of red, green, and blue, the cathode-forming metal, and the photoresist are laminated and the photoresist is formed. And patterning the resist, the cathode electrode forming metal, and the organic material having any one of red, green, and blue to form a pixel is repeatedly performed three times. The method of claim 2, wherein the predetermined gas for dry etching the cathode electrode forming metal is a chloride gas, and the predetermined gas for dry etching the organic material is an oxygen gas. . The method of manufacturing an organic light emitting display device according to any one of claims 1 to 4, wherein the organic material is a polymer organic material.