KR100752385B1 - Organic light emitting display device and the fabricating method of the same - Google Patents

Abstract

An organic light emitting display device and a manufacturing method thereof are provided to enhance the operation reliability of the display device by preventing a pixel shrinkage phenomenon. A TFT(Thin Film Transistor)(115) is formed on a substrate(100). A protective film(170) is arranged to cover an overall surface of the substrate. A first planarization film(180a) is formed on the protective film in an island shape and exposes a portion of the protective film. A second planarization film(180b) is formed on an overall surface of the substrate including the first planarization film. A pixel electrode(200) is formed on the second planarization film and connected to one of the source/drain electrodes of the TFT through a via-hole formed on the second planarization film. An organic film pattern(320') includes at least one light emitting layer formed on the pixel electrode. An upper electrode(330) is arranged on the organic film pattern.

Description

Organic Light Emitting Display Device and The Fabricating method of The Same

1 is a cross-sectional view of a method of manufacturing a conventional organic light emitting display device.

2 is a cross-sectional view of a method of manufacturing an organic light emitting display device according to an embodiment of the present invention;

3 is a photograph taken with an optical microscope of a plane of a conventional organic electroluminescent display.

<Brief Description of Drawings>

180a: first planarization film

180b: second planarization film

200: pixel electrode

160a: drain electrode

160b: source electrode

170: shield

The present invention relates to an organic light emitting display device and a method of manufacturing the same. More particularly, the first planarization layer is formed in an island shape, and the second planarization layer is formed to remove the step of the process before the planarization organic layer and to reduce the thickness of the planarization layer. The present invention relates to a method of manufacturing an organic light emitting display device that minimizes pixel shrinkage.

With the advent of the high information age, there is an increasing demand for obtaining fast and accurate information in the hand, and the development of a display device that is light and thin, easy to carry, and has a high information processing speed is rapidly being made. Conventional CRTs have high weight, volume, and power consumption, and LCDs have technical limitations on process complexity, narrow viewing angles, contrast ratios, and large area. Organic electroluminescent display devices that solve these problems are rapidly rising as the next generation display.

The organic light emitting display device is a self-luminous type in which electrons and holes are recombined in the light emitting layer to generate light by applying a voltage to the organic layer including the organic light emitting layer. The response speed is the same as the CRT, and it is advantageous in terms of power consumption.

In general, an organic light emitting display device includes a plurality of layers such as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer between an anode and a cathode. Full color can be realized by patterning a light emitting layer showing three primary colors of.

The multilayer organic film may form an organic film pattern using a vacuum deposition method or a conventional optical etching method using a shadow mask, but in the case of the vacuum deposition method, it is difficult to form the organic film in a fine pattern, so it is not easy to realize a full color. In the case of the photoetching method, there is a problem in that light emission characteristics such as lifetime and efficiency are deteriorated due to damage of the organic layer by the developer or the etchant.

1 is a cross-sectional view illustrating a manufacturing process of a conventional organic light emitting display device.

Referring to FIG. 1, a buffer layer 11 is formed on an insulating substrate 10, and a thin film transistor 20 is formed on the buffer layer 11.

The thin film transistor 20 is formed of a source / drain electrode material on the semiconductor layer 21, the gate insulating layer 12, the gate electrode 22, the interlayer insulating layer 13, and the interlayer insulating layer formed on the buffer layer 11. Source / drain electrodes 23, 23 'are made.

Subsequently, a passivation layer 14 is formed over the entire surface of the interlayer insulating layer 13 including the thin film transistor 20, a planarization layer 15 is formed on the passivation layer 14, and the drain electrode 23 ′ is formed. A via hole 41 is formed to expose a predetermined portion of the.

The pixel electrode 42 is formed to contact the exposed portion of the drain electrode 23 ′ through the via hole 41.

In this case, a pixel defining layer 16 is formed in a portion except for the opening on the pixel electrode 42, and an organic layer 62 ′ including an organic light emitting layer is formed in the opening region on the pixel electrode 42. The upper electrode 17 is formed over the entire surface.

In this case, the planarization film is formed to overcome the step difference caused by the thin film transistor 20 of the substrate, but the planarization film 16 should be formed thick because the region where the thin film transistor is formed is high. In general, when the planarization film is formed thick, the planarization degree is increased, and the parasitic capacitor is prevented. However, a long process time is required to form a thick planarization film. In addition, the planarization film is formed using an organic film such as acrylic, polyimide, photosensitive resist, and the like, which emits outgas at a high temperature and affects the organic light emitting layer, thereby deteriorating the organic light emitting layer, and thus, pixel shrinkage. There is a problem that can cause (pixel shrinkage).

Meanwhile, FIG. 3 is a photograph taken by an optical microscope of a plane of a conventional organic electroluminescent display, and it can be seen that there is a step in the organic electroluminescent display due to a difference in contrast between the 'a' portions. The darker areas are lower than the brighter areas.

The technical problem to be achieved by the present invention is to compensate for the problems of the prior art described above, an object of the present invention is to change the deposition structure of the planarization film to make the thickness as thin as possible to prevent pixel shrinkage while improving the degree of flatness of the organic electroluminescence A display device and a method of manufacturing the same.

An organic electroluminescent display and a method of manufacturing the same, more specifically, a substrate; A thin film transistor formed on the substrate; A passivation layer positioned over the entire surface of the substrate including the thin film transistor; A first planarization layer formed on the passivation layer in an island shape to expose a portion of the passivation layer; A second planarization layer on a front surface of the substrate including the first planarization layer; A pixel electrode formed on the second planarization layer and connected to one of the source / drain electrodes of the thin film transistor through a via hole formed in the second planarization layer; An organic film layer pattern including at least a light emitting layer on the pixel electrode; And an upper electrode disposed on the organic film layer pattern.

In addition, a substrate is provided, a thin film transistor is formed on the substrate, a protective film is formed over the entire surface of the substrate including the thin film transistor, and is disposed on the protective film and formed in an island shape in a partial region. A first planarization layer is formed to expose a portion of the second planarization layer, a second planarization layer is formed on the entire surface of the substrate including the first planarization layer, and is formed in a partial region on the second planarization layer, and a via hole formed in the second planarization layer A pixel electrode connected to any one of the source / drain electrodes of the thin film transistor is formed, an organic layer pattern including at least a light emitting layer is formed on the pixel electrode, and an upper electrode on the organic layer pattern In the method of manufacturing an organic light emitting display device comprising the step of forming a It is about.

2 is a cross-sectional view of an organic light emitting display device according to an exemplary embodiment of the present invention.

Hereinafter, referring to FIG. 2, the thin film transistor 115 is positioned on the substrate 100. In more detail, a buffer layer 110 may be disposed on the substrate 100 to prevent impurities flowing out of the substrate 100. A semiconductor layer 120 is formed on the buffer layer 110 and includes a source / drain region 120b / 120a and a channel region 102c by implanting impurities. A gate insulating layer 130 is positioned on the semiconductor layer 120, and a gate electrode 140 is positioned on the semiconductor layer 120 on the gate insulating layer 130. Then, the interlayer insulating layer 150 is positioned on the gate electrode 140, and the source / drain electrodes 160b and 160a are positioned on the interlayer insulating layer 150, thereby forming the thin film transistor 115. The above-described structure can also be applied to a top gate structure or a bottom gate structure.

Thereafter, the passivation layer 170 may be positioned on the thin film transistor 115. The protective film 170 may be made of an inorganic material. For example, the protective film may be formed of one material selected from a silicon oxide film, a silicon nitride film, and a laminated film of a silicon oxide film and a silicon nitride film.

Subsequently, a first planarization layer 180a may be formed on the passivation layer 170 and may expose a portion of the passivation layer positioned on the thin film transistor 115 region. Here, the passivation layer of the upper portion of the thin film transistor 115 may be exposed and may be the highest region, but the height of the first planarization layer 180a may be lower than the height of the exposed passivation layer based on the substrate. After forming the first planarization layer 180a in an island form, the second planarization layer 180b is formed once more. The height of the second planarization layer 180b may be higher than or equal to the height of the exposed protective layer based on the substrate. The sum of the thicknesses of the first planarization layer 180a and the second planarization layer 180b may be 1 μm to 2 μm, and thus may be thinner than that of the related art.

 Subsequently, the pixel electrode 200 is electrically connected to the drain electrode 160a of the thin film transistor through the via hole 190 formed on the planarization layer 180b. The pixel defining layer 210 may further include a pixel defining layer 210 positioned on the pixel electrode 200 and having an opening 220 exposing the emission region of the pixel electrode. An organic layer pattern 320 ′ including at least a light emitting layer is positioned on the pixel electrode 200, and an upper electrode 330 is positioned on the organic layer pattern.

Next, a method of manufacturing an organic light emitting display device according to an exemplary embodiment of the present invention will be described with reference to FIG. 2.

 Referring to FIG. 2, a substrate 100 is provided, and a buffer layer 110 selected from the group consisting of a silicon oxide film, a silicon nitride film, and a laminated film of a silicon oxide film and a silicon nitride film to prevent impurities flowing out from the substrate 100. ).

After depositing an amorphous silicon film on the buffer layer 110, the amorphous silicon film is crystallized through a conventional crystallization method and then patterned to form a semiconductor layer 120. Thereafter, the gate insulating layer 130 is formed over the entire surface of the substrate including the semiconductor layer 120. Subsequently, a conductive film is formed on the gate insulating layer 130 and then patterned to form a gate electrode 140 at a portion spaced apart from the semiconductor layer 120 and an ion doping treatment is performed on the semiconductor layer 120. As a result, after forming the drain region 120a, the source region 120b, and the channel region 120c, the interlayer insulating layer 150 is formed on the gate insulating layer including the gate electrode 140. In this case, the gate electrode material is made of at least one metal material including a metal material such as chromium (Cr), molybdenum (Mo), or aluminum (Al) or an alloy thereof.

Subsequently, the gate insulating layer 130 and the interlayer insulating layer 150 are etched to expose the first contact hole 125a and the second contact hole 125b exposing predetermined portions of the drain region 120a and the source region 120b. And source / drain electrodes 160a and 160b electrically connected to the source / drain regions 120b and 120a, respectively, on the interlayer insulating layer 150 including the contact holes 125a and 125b. The passivation layer 170 is formed on the entire surface of the interlayer insulating layer 150 including the source / drain electrodes. The source / drain electrode material may be formed of at least one metal material including a metal material such as tungsten (W), molybdenum (Mo), or aluminum (Al) or an alloy thereof.

Thereafter, a first planarization layer 180a is formed on the passivation layer 170 to overcome the step difference. The first planarization layer 180a is formed in a partial region on the passivation layer, and is formed in an island shape so as not to overlap with other patterns. In this case, the first planarization layer 180a may be formed of an organic layer having good fluidity. Thereafter, a second planarization layer 180b is formed over the entire surface of the first planarization layer 180a and the interlayer insulating layer 150. At this time, the second planarization film 180b is more preferably made of a photosensitive resin as an organic film. For example, the photosensitive resin may be a material selected from the group consisting of polyamide resin, polyimide resin, acrylic resin, benzocyclobutyne resin, PBO and silicone resin, or a material in which two or more materials are combined.

In this case, the height of the second planarization layer 180b may be higher than or equal to the height of the exposed passivation layer 170 based on the substrate, and the exposed passivation layer 170 is formed on the top of the thin film transistor. It may be an area.

In this case, when the height of the second planarization layer 180b is the same as the exposed passivation layer, the second planarization layer 180b may be formed over the entire surface of the substrate and then removed by a dry etching method or a wet etching method. In addition, when the second planarization layer 180b is an organic film made of photosensitive resin, the second planarization layer 180b may be easily removed by a post-exposure developer over the entire surface of the second planarization layer 180b. In this case, the thickness of the second planarization layer 180b on the region having the same high substrate height as the region of the thin film transistor 115 is formed to be thinner than the thickness of the second planarization layer 180b on the lower region. Therefore, when the entire planarization film is removed by exposing the entire surface of the second planarization film 180b, the second planarization film on the high region is removed before the second planarization film on the lower region relative to the substrate. At this time, since the protective film 170 formed of the inorganic film is present under the second planarization film 180b, it is not affected by the exposure. As a result, the second planarization layer 180b having a high region is removed based on the substrate to expose the passivation layer 170 under the second planarization layer.

Subsequently, as shown in FIG. 2, a via hole 190 exposing one of the source / drain electrodes 160a and 160b is formed on the second planarization layer 180b pattern, and then the source / drain layer is formed on the planarization layer. The pixel electrode 200 connected to any one of the drain electrodes 160a and 160b is formed. In the exemplary embodiment of the present invention, the pixel electrode 200 is formed to be connected to the drain electrode 160a through the via hole.

A pixel definition layer 210 may be further formed on the entire surface of the substrate on which the pixel electrode 200 is formed to cover the curved pixel electrode. In this case, the thickness of the pixel definition layer 210 is not limited to a thickness of 5000 kPa to 10000 kPa or less. Because too thin is difficult to deposit, too thick is difficult to complete the thin film device. The pixel defining layer 210 may be formed of polystyrene, polymethyl ketaacrylate, polyacrylonitrile, polyamide, polyimide, polyaryl ether, heterocyclic polymer, parylene, fluorine polymer, epoxy resin, or benzocyclo. It may be formed of one material selected from the group consisting of butene resin, siloxane resin and silane resin.

Thereafter, the pixel defining layer 210 is patterned to form an opening 220 that exposes a predetermined portion of the pixel electrode. As a result, the planarizing substrate 250 may be manufactured by removing the planarization layer of the portion where the planarization degree is not improved by the planarization layer. Subsequently, an organic layer pattern including at least a light emitting layer is formed on the pixel electrode 200 exposed through the opening. The organic layer pattern may be formed by selecting one of laser thermal transfer, spin coating, and low molecular deposition.

Subsequently, the upper electrode 330 is formed on the organic layer pattern, and although not shown in the drawing, the upper electrode 330 may be encapsulated with a metal can and an encapsulation substrate to complete the organic light emitting display device.

As described above, by forming the island-shaped first planarization film and forming the second planarization film, it is possible to prevent pixel shrinkage occurring in the conventional planarization film that is thickly formed in order to improve the planarization degree, thereby making it reliable. The defect of the organic electroluminescent display device can be improved.

Claims (9)

Board; A thin film transistor formed on the substrate; A passivation layer positioned over the entire surface of the substrate including the thin film transistor; A first planarization layer formed on the passivation layer in an island shape to expose a portion of the passivation layer; A second planarization layer on a front surface of the substrate including the first planarization layer; A pixel electrode formed on the second planarization layer and connected to one of the source / drain electrodes of the thin film transistor through a via hole formed in the second planarization layer; An organic film layer pattern including at least a light emitting layer on the pixel electrode; And And an upper electrode disposed on the organic layer pattern. The method of claim 1, And the sum of the thicknesses of the first planarization film and the second planarization film is in a range of 1 µm to 2 µm. The method of claim 1, The height of the first planarization layer is lower than the height of the exposed protective layer relative to the substrate. The method of claim 1, And a height of the second planarization layer is higher than or equal to a height of the exposed protective layer on the substrate. The method of claim 1, And a height of the pixel electrode is higher than or equal to a height of the exposed passivation layer based on the substrate. The method of claim 1, And the first planarization film and the second planarization film are made of photosensitive resin. The method of claim 6, The first and second planarization films are formed of one material selected from the group consisting of polyamide resin, polyimide resin, acrylic resin, benzocyclobutyne resin, PBO and silicone resin, or a material in which two or more materials are combined. An organic electroluminescent display device. The method of claim 1, And the region where the passivation layer is exposed is an uppermost region of the thin film transistor. Providing a substrate, Forming a thin film transistor on the substrate, Forming a protective film over the entire surface of the substrate including the thin film transistor, Located on the passivation layer and formed in an island shape in a partial region, a first planarization layer is formed to expose a portion of the passivation layer. Forming a second planarization film on the entire surface of the substrate including the first planarization film, A pixel electrode formed in a portion of the second planarization layer and connected to one of the source / drain electrodes of the thin film transistor through a via hole formed in the second planarization layer; Forming an organic layer pattern including at least an emission layer on the pixel electrode; And forming an upper electrode on the organic layer pattern.

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