KR100714012B1 - Organic light emitting display and method for fabricating the same - Google Patents

Abstract

According to the present invention, when the front emission organic light emitting display device is manufactured in a large area, a step is formed in the first electrode layer by using a planarization film having a step, so that the first electrode layer is formed in the region of the step where the first electrode layer and the second electrode layer are in contact with each other. The present invention relates to an organic light emitting display device and a method of manufacturing the same, which can reduce the resistance of the second electrode layer with high conductivity of the electrode layer. An organic light emitting diode display according to the present invention includes a planarization film formed on at least one step on a substrate; A first electrode layer formed on a lower region of the step of the planarization film; An auxiliary metal layer formed on a high region of the step of the planarization film; A pixel definition layer formed to fill between the first electrode layer and the auxiliary metal layer; An organic layer formed on the first electrode layer between the pixel definition layers; And a second electrode layer formed on the organic layer, the auxiliary metal layer, and the pixel definition layer. By this configuration, not only the voltage drop (IR drop) can be prevented, but also the mirror effect can be exhibited by the first electrode layer formed of the reflective film.

Planarization film, step, auxiliary metal layer

Description

Organic light emitting display and method for manufacturing the same {Organic light emitting display and method for fabricating the same}

1 is a cross-sectional view illustrating an organic light emitting display device according to the prior art.

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

3A to 3H are cross-sectional views of manufacturing steps of an organic light emitting diode display according to an exemplary embodiment of the present invention.

♣ Explanation of symbols for the main parts of the drawing ♣

209a and 312a: first electrode layer 209b and 312b: auxiliary electrode layer

208a and 308a flattening films 208b and 308b

210, 313: Pixel defining films 212, 314: Organic film layers

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display device and a method of manufacturing the same. More particularly, when a top emitting organic light emitting display device is manufactured in a large area, a step is formed in the first electrode layer by a planarization film having a step, The present invention relates to an organic light emitting display device and a method of manufacturing the same, which can reduce the resistance of the second electrode layer with a high conductivity of the first electrode layer in a high region of the step where the first electrode layer and the second electrode layer contact each other.

Recently, a flat panel display (FPD: Flat Panel Display) having the advantages of small size and light weight by solving problems of weight and size of a cathode ray tube (CRT) has been attracting attention. Such flat panel displays include liquid crystal displays (LCDs), light emitting diodes (LEDs), field emitter displays (FEDs), and plasma display panels (PDPs). There is this.

Among the flat panel display devices, the light emitting display device has a wider operating temperature range than other flat panel display devices, is resistant to shock and vibration, has a wide viewing angle, and provides a fast response speed, thereby providing clean moving images. In the future, it is attracting attention as the next generation flat panel display.

Such light emitting display devices include an organic light emitting display device using an organic light emitting display device and an inorganic light emitting display device using an inorganic light emitting display device. The organic light emitting display device includes a first electrode layer, a second electrode layer, and an organic light emitting layer disposed between the first and second electrode layers to emit light by a combination of electrons and holes. The inorganic light emitting display device, unlike the organic light emitting display device, includes an emission layer made of an inorganic material, for example, a light emitting layer made of a PN bonded semiconductor.

Among them, when the organic light emitting diode display is manufactured in a large area, a voltage drop (IR drop) occurs because the second electrode layer is formed of a thin metal. Therefore, various techniques for preventing such a voltage drop are known.

Hereinafter, an organic light emitting diode display according to the related art will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view illustrating an organic light emitting display device according to the related art.

As shown in FIG. 1, a conventional organic light emitting display device includes a substrate 101, a buffer layer 102 formed on the substrate 101, an active layer 103a formed on one region of the buffer layer 102, and There is a semiconductor layer 103 formed of an ohmic contact layer 103b and a gate insulating layer 104 formed on the semiconductor layer 103. The gate electrode 105 formed on one region of the gate insulating layer 104 and the interlayer insulating layer 106 are formed on the gate electrode 105. The source and drain electrodes 107a and 107b formed on one region of the interlayer insulating layer 106 are formed to be connected to the one region where the ohmic contact layer 103b is exposed, and the source and drain electrodes 107a, The planarization layer 108 is formed on 107b. The first electrode layer 109 formed on one region of the planarization layer 108 is formed to be connected to one region where the source and drain electrodes 107a and 107b are exposed, and the first electrode layer 109 and the planarization layer are formed. A pixel definition layer 110 having an opening 113 exposing at least one region of the first electrode layer 109 is formed on the layer 108. An emission layer 112 is formed on the opening 113, and a second electrode layer 114 is formed on the emission layer 112 and the pixel definition layer 110.

However, when the organic light emitting diode display is manufactured in a large area, a voltage drop (IR drop) occurs because the second electrode layer is made of a thin metal of about 100 GPa, and a defect occurs in the organic light emitting diode display. There is a problem.

Accordingly, the present invention is an invention designed to solve the above-mentioned problems, and an object of the present invention is to provide a stepped surface on a first electrode layer by a planarization film having a step formed when a large area of a top-emitting organic light emitting display device is manufactured. The present invention provides an organic light emitting display device and a method of manufacturing the same, which can reduce the resistance of the second electrode layer with a high conductivity of the first electrode layer in a high region of the step where the first electrode layer and the second electrode layer contact each other.

In order to achieve the above object, an organic light emitting diode display according to an embodiment of the present invention is a planarization film formed with at least one step on a substrate, and a first electrode layer formed on a lower region of the step of the planarization film And an auxiliary metal layer formed on a high region of the leveling step of the planarization film, a pixel definition film formed to fill the first electrode layer and the auxiliary metal layer, and a first electrode layer between the pixel definition film. An organic layer, a second electrode layer formed on the organic layer, the auxiliary metal layer, and the pixel defining layer;

In addition, according to another embodiment of the present invention, a method of manufacturing an organic light emitting display device includes forming a planarization film on a substrate, applying a photoresist on the planarization film, and a mask on which a pattern is formed on the photoresist. Positioning a light source, irradiating a light source, etching and washing the photoresist, patterning the flattening film to have a step, forming a first electrode layer on a lower region of the step of the flattening film, and Forming an auxiliary metal layer on a high region of the substrate; forming a pixel definition layer to fill the first electrode layer and the auxiliary metal layer; and forming an organic layer on the first electrode layer between the pixel definition layer. step; And forming a second electrode layer on the organic layer, the auxiliary metal layer, and the pixel definition layer.

Hereinafter, an organic light emitting diode display and a method of manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings.

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

As shown in FIG. 2, first, at least one thin film transistor is formed on the substrate 201. When the structure of the thin film transistor formed on the substrate 201 is briefly described, a buffer layer 202 is formed on the substrate 201 and the active channel layer 203a and the ohmic contact formed on the buffer layer 202 are formed. A semiconductor layer 203 including an LDD layer (not shown) is formed between the layers 203b. The gate insulating layer 204 and the gate electrode 205 are patterned and sequentially formed on the semiconductor layer 203. An interlayer insulating layer 206 formed on the gate electrode 205 and exposing the ohmic contact layer 203b of the semiconductor layer 203, and the source and drain electrodes on the interlayer insulating layer 206. 207a and 207b and the exposed ohmic contact layer 203b are formed in contact with each other.

The planarization layer 208 having a step is formed on the thin film transistor. The first electrode layer 209a is formed on the lower region of the step 208b of the planarization film 208a, and the auxiliary metal layer 209b is formed on the high region of the step 208b of the planarization film 208a. Since the organic light emitting diode display according to the present invention is top emission, the first electrode layer 209a is formed of a reflective film.

One of the source and drain electrodes 207a and 207b of the thin film transistor is connected to the first electrode layer 209a on the planarization layer 208a. One area of the planarization layer 208a may be etched on the planarization layer 208a to expose one of the source and drain electrodes 207a and 207b so as to expose the organic light emitting diode display and the first electrode layer. 209a) is electrically connected.

In addition, a pixel definition layer 210 is formed to fill between the first electrode layer 209a and the auxiliary metal layer 209b, and an organic layer formed on the first electrode layer 209a formed between the pixel definition layer 210. 212 is formed. A second electrode layer 215 is formed on the organic layer 212, the auxiliary metal layer 209b, and the pixel definition layer 210. The organic layer 212 is an electron injection layer, an electron transport layer, a light emitting layer, a hole transport layer and a hole injection layer.

The planarization film 208a is formed in an inverse taper shape, and the first electrode layer 209a and the auxiliary metal layer 209b are separated by the planarization film 208a having a step 208b having an inverse taper shape. It is formed independently.

The step 208b of the planarization film 208a is formed in a height range of 0.4 μm to 1.0 μm, and the width of the auxiliary metal layer 209b is smaller than the width of the first electrode layer 209a. Preferably, the auxiliary metal layer 209b and the first electrode layer 209a are formed in a ratio of 3: 7. The auxiliary metal layer 209b is formed of the same material as the first electrode layer 209a.

3A to 3H are cross-sectional views illustrating a manufacturing step of the organic light emitting diode display of FIG. 2. For convenience of description, detailed descriptions of the same elements as those of FIG. 2 will be omitted. In particular, detailed description of each layer of the organic light emitting diode display will be omitted.

Referring to FIGS. 3A to 3H, a manufacturing step of an organic light emitting diode display according to another exemplary embodiment of the present invention will be described. A planarization layer 308a is formed on a thin film transistor (FIG. 3A). The photoresist 309 is applied onto the photoresist. (FIG. 3B) In the present invention, a negative photoresist is applied.

After applying the negative photoresist 309, a mask 310 having a pattern formed on the negative photoresist 309 is positioned (FIG. 3C). The mask 310 is the planarization layer 308a. The portion of the step 308b of the high region to be formed has a shape that is bored.

Next, the light source 311 is irradiated on the mask 310. (FIG. 3D) The light source 311 is mounted on a separate moving means and moves to a light source on the mask 310 and the planarization film 308a. Investigate (311). Alternatively, the light source 311 is irradiated to the mask 310 and the planarization layer 308a by providing at least one light source 311.

Then, when the mask 310 and the light source 311 are removed and the photoresist 309 is etched, the photoresist 309 remains on the planarization film 308a in the high region of the step 308b. Since the negative photoresist 309 is used, the photoresist 309 of the portion covered by the mask 310 is etched to form an inverted tapered step 308b on the planarization film 308a. Will be. Here, KOH is used as an etching solution of the negative photoresist 309.

In this state, the photoresist 309 remaining on the planarization film 308a is washed and removed, and the auxiliary metal layer 312b is formed in the high region of the step 308b, and the low of the step 308b is formed. The first electrode layer 312a is formed in the region (FIG. 3f). The auxiliary metal layer 312b is simultaneously formed of the same material as the first electrode layer 312a. The first electrode layer 312a is electrically connected to one of the source and drain electrodes 307a and 307b by etching the planarization layer 308a.

The first electrode layer 312a and the auxiliary metal layer 312b are separated from each other by the planarization layer 308a having a step 308b having an inverse taper shape and formed independently. In addition, since the organic light emitting diode display according to the present invention emits top surface light, a reflective film is formed on the first electrode layer 312a to have a mirror effect.

Thereafter, a pixel definition layer 313 is formed to fill the gap between the first electrode layer 312a and the auxiliary metal layer 312b. (FIG. 3G) The first electrode layer formed between the pixel definition layer 313 is formed. An organic layer 314 is formed on the 312a layer, and a second electrode layer 315 is formed on the organic layer 314, the auxiliary metal layer 312b, and the pixel defining layer 313. )

Therefore, the first electrode layer and the semi-transmissive second electrode layer are brought into contact with each other, and the resistance of the second electrode layer is reduced due to the high conductivity of the first electrode layer. IR drop) can be prevented.

In the above-described embodiment, the first planarization film and the second planarization film are simultaneously formed using a negative photoresist. However, the second planarization film may be formed through a separate process after the first planarization film is formed. In addition, although the exemplary embodiment of the present invention has been described with respect to the active organic light emitting display device, it is also applicable to the passive organic light emitting display device.

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

As described above, according to the present invention, when fabricating a top-emitting organic light emitting diode display with a large area, a step is formed in the first electrode layer by using a planarization film having a step, and the first electrode layer is formed at a high level among the steps. By contacting the second electrode layer, the resistance of the second electrode layer can be reduced by the high conductivity of the first electrode layer, thereby preventing voltage drop, and exhibiting a mirror effect by the first electrode layer formed of the reflective film. have.

Claims (13)

A planarization film formed on the substrate with at least one step; A first electrode layer formed on a lower region of the step of the planarization film; An auxiliary metal layer formed on a high region of the step of the planarization film; A pixel definition layer formed to fill between the first electrode layer and the auxiliary metal layer; An organic layer formed on the first electrode layer between the pixel definition layers; And And a second electrode layer formed on the organic layer, the auxiliary metal layer, and the pixel definition layer. The organic light emitting display device of claim 1, wherein the planarization layer is formed in an inverse taper shape. The organic light emitting display device of claim 1, wherein the first electrode layer and the auxiliary metal layer are formed independently from each other by the planarization layer having an inverse tapered step. The organic light emitting diode display of claim 1, wherein the step is formed in a height range of 0.4 μm to 1.0 μm. The organic light emitting diode display of claim 1, wherein a width of the auxiliary metal layer is smaller than a width of the first electrode layer. The organic light emitting display device of claim 5, wherein the auxiliary metal layer and the first electrode layer are formed in a ratio of 3: 7. The organic light emitting display device of claim 1, wherein the auxiliary metal layer is formed of the same material as the first electrode layer. Forming a planarization film on the substrate; Applying a photoresist on the planarization film; Positioning a mask on which the pattern is formed on the photoresist, and irradiating a light source; Etching and washing the photoresist to pattern the planarization layer to have a step; Forming a first electrode layer on a lower region of the step of the planarization film, and forming an auxiliary metal layer on a region of the high level of the step of the planarization film; Forming a pixel definition layer to fill the first electrode layer and the auxiliary metal layer; Forming an organic layer on the first electrode layer formed between the pixel definition layer; And And forming a second electrode layer on the organic layer, the auxiliary metal layer, and the pixel definition layer. The method of claim 8, wherein in the applying of the photoresist, the photoresist used is a negative photoresist. The method of claim 8, wherein in the etching of the photoresist, the photoresist etching solution is KOH. The method of claim 8, wherein in the step of patterning the flattening film to have a step, the flattening film is formed in an inverse taper shape. The organic light emitting diode of claim 11, wherein in the patterning of the planarization layer to have a step, the first electrode layer and the auxiliary metal layer are separated and formed independently of the planarization layer having a step of reverse taper. Method for manufacturing a display device. The method of claim 11, wherein in the forming of the first electrode layer and the auxiliary metal layer, the auxiliary metal layer is formed of the same material as the first electrode layer.

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