KR100357102B1 - fabrication method of organic electroluminescent display panel - Google Patents

Abstract

A method of manufacturing an organic electroluminescent display panel, comprising: a first electrode and a second electrode formed on a transparent substrate, and a method of manufacturing an organic electroluminescent display panel having a plurality of pixels formed of at least one organic light emitting layer formed therebetween. A first step of forming a first electrode on a substrate, a second step of sequentially forming at least one organic light emitting layer using a first shadow mask on the first electrode, and using a second shadow mask on the organic light emitting layer A third step of forming a second electrode, and a fourth step of patterning the second electrode for electrical insulation between adjacent pixels by dry etching. Here, after the first step, at least one spacer may be formed on the first electrode. In addition, the dry etching method uses any one of a laser beam, an ion beam, and a plasma. According to the present invention, since the shadow mask and the dry etching method are used, the manufacturing method of the organic electroluminescent display panel is simple and the production yield can be increased.

Description

Fabrication method of organic electroluminescent display panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to display devices, and more particularly, to a method of manufacturing an organic electroluminescent display panel.

Recently, as the size of the display device increases, the demand for a flat display device having less space occupancy is increasing. As one of the flat display devices, an electroluminescent device is attracting attention.

The electroluminescent device is divided into inorganic electroluminescent device and organic electroluminescent device according to the material used. Among them, the organic electroluminescent device is formed in the organic light emitting layer formed between the electron injection electrode (cathode) and the hole injection electrode (anode). When the charge is injected, electrons and holes are paired and extinguished while emitting light. It has the advantage that it can be driven at lower voltage (5 ~ 10V) than plasma display panel (PDP) or inorganic electroluminescent device display. Is actively underway.

In addition, organic electroluminescent devices have excellent characteristics such as wide viewing angle, high-speed response and high contrast, so that they can be used as pixels in graphic displays, television image displays or surface light sources. The device can be formed on a flexible transparent substrate, such as plastic, and is suitable for the next-generation flat panel display because it is thin, light, and has good color.

1 is a plan view of a simple matrix organic electroluminescent display panel having such a use.

First electrodes 2 formed in a stripe shape on the transparent substrate 1, organic light emitting layers 4 formed by vacuum deposition on the first electrodes 2, and second electrodes 3. Is done.

The organic light emitting layer 4 includes a hole injecting layer (HIL) and / or a hole transporting layer (HTL) formed on the first electrode 2, and an organic light emitting layer formed on the hole injecting layer or the hole transporting layer. And an electron transporting layer (ETL) and / or an electron injection layer (EIL) formed on the organic light emitting layer.

The second electrode 3 of the organic electroluminescent display panel formed as described above functions to inject electrons into the organic light emitting layer through the electron injection layer and / or the electron transport layer of the organic light emitting layer 4, and the first electrode 2. ) Functions to inject holes into the organic light emitting layer through the hole injection layer and / or hole transport layer.

However, such an organic electroluminescent display panel has a lot of difficulties in manufacturing, the most difficult process is the pixelation (patterning) or patterning (patterning) process.

That is, ITO (Indium Tin Oxide), which is commonly used as the strip of the first electrode 2, can be easily patterned using a photolithogaphy process which is commonly used in semiconductor manufacturing processes, but patterning of the second electrode is very simple. Not.

The reason is that it is difficult to use a general photolithography process because the organic light emitting layer 4 already formed under the second electrode 3 is degraded when exposed to water or solvent during the photolithography process.

2 is a process cross-sectional view of an organic electroluminescent display panel according to a first embodiment of the prior art for solving the above problems, the first electrode 2 and the organic light emitting layer 4 is formed on a transparent substrate 1 The method of forming the second electrode 3 using the shadow mask 5 is illustrated.

3 is a process cross-sectional view of an organic electroluminescent display panel according to a second embodiment of the prior art. After forming the first electrode 2 on the transparent substrate 1, the buffer layer 7 is formed. After the partition 6 is formed of the photoresist on the formed buffer layer 7, the organic light emitting layer 4 is formed on the entire surface, and the second electrode 3 is formed again to form the organic light emitting layer 4 and the second electrode ( 3) shows a method of pattern separation.

However, using the above methods, it is possible to produce a monochromatic organic electroluminescent display panel, but in order to manufacture a multicolor organic electroluminescent display panel, other techniques may be added to the method of manufacturing a monochromatic organic electroluminescent display panel. Since it is necessary, it is rather complicated compared with manufacturing a monochromatic organic electroluminescent display panel.

Conventional techniques for fabricating a multicolor organic electroluminescent display panel include the following methods.

A method of using white light, a color filter, a blue light, and a color changing medium (CCM), a method of using a partition and a shadow mask, and a method of using dry etching may be considered.

Here, a method in which white light or blue light is incident on a color filter or a color conversion material to obtain three colors of red, blue, and green, respectively, generates a strong white light or blue light despite the very important advantage that the subsequent process is simple. There is a critical problem that it is difficult to obtain organic materials and highly efficient color conversion materials, especially red materials.

In addition, the use of color converting materials or color filters makes other processes very complicated, and from a cost point of view, a method of simultaneously using a barrier and a shadow mask is the simplest method.

FIG. 4 is a process cross-sectional view of an organic electroluminescent display panel according to a third embodiment of the prior art, and illustrates a process of a multicolor organic electroluminescent display panel using a partition and a shadow mask simultaneously.

That is, as illustrated in FIGS. 4A to 4D, the organic light emitting layer emitting red, green, and blue light is separately deposited using a shadow mask.

First, as shown in FIG. 4A, the first electrode 2 strips are formed on the transparent substrate 1, and the partition walls 6 are formed in advance to form the second electrode strips on the substrate.

Then, shadow masks prepared for each of three colors of red, blue, and green are sequentially used to form an organic light emitting layer emitting each color.

For example, during formation of the green light emitting layer, red and blue bands are covered by the shadow mask to prevent the green light emitting material from being applied to the portion.

As shown in FIG. 4A, three red partitions 6 are skipped to form one red emitting material layer 4-1 by using the shadow mask 5 having only a red pixel portion.

4B and 4C, the green light emitting material layer 4-2 and the shadow mask 5 are moved side by side in the same manner as the method of forming the red light emitting material layer 4-1. The blue light emitting material layer 4-3 is formed.

Then, as shown in FIG. 4D, when the second electrode 3 is formed on the front side with the shadow mask removed, partitioning of the second electrode 3 occurs by the partition wall 6, thereby forming the multicolor organic electroluminescent display panel. This is produced.

However, the method of using the shadow mask and the partition at the same time has a disadvantage that the process of making the partition can be a factor that reduces productivity.

In addition, since the barrier and overhang are usually made of weak photoresist, when the shadow mask is sequentially moved to form a red, blue, and green light emitting layer, the shadow mask and the barrier are subjected to friction, or during substrate transfer during the deposition process. Due to the vibration of the shadow mask, the overhang portion collapses or the partition wall itself is broken so that the second electrode cannot be divided and thus the second electrode is bundled in multiple lines, or the short between the first electrode and the second electrode is short. Can cause fatal crosstalk during operation.

The present invention is to solve the above problems, by separating and depositing the organic light emitting layer using a shadow mask, and by performing a patterning of the second electrode using a dry etching method, the process is simple and high yield multicolor organic electric field It is an object of the present invention to provide a method of manufacturing a light emitting display panel.

1 is a plan view of an organic electroluminescent display panel according to a simple matrix method of the prior art.

2 is a process cross-sectional view of an organic electroluminescent display panel according to a first embodiment of the prior art.

3 is a process cross-sectional view of an organic electroluminescent display panel according to a second embodiment of the prior art.

4 is a process cross-sectional view of an organic electroluminescent display panel according to a third embodiment of the prior art.

5 is a process cross-sectional view of an organic electroluminescent display panel according to the present invention.

6 is a process plan view of an organic electroluminescent display panel according to the present invention.

* Explanation of symbols for main parts of the drawings

501 transparent substrate 506 green organic light emitting layer

502: First electrode 508: Blue organic light emitting layer

503: buffer layer 505, 510: shadow mask

504: red organic light emitting layer 511: second electrode

An organic electroluminescent display panel according to the present invention for achieving the above object is characterized by having a first electrode and a second electrode formed on a transparent substrate, and a plurality of pixels consisting of at least one organic light emitting layer formed therebetween A method of manufacturing an organic electroluminescent display panel, comprising: a first step of forming a first electrode on a substrate, a second step of sequentially forming at least one organic light emitting layer on the first electrode by using a first shadow mask; And a fourth step of forming a second electrode on the organic light emitting layer by using a second shadow mask, and a fourth step of patterning the second electrode for electrical insulation of isolation of adjacent pixels by dry etching.

In still another aspect of the present invention, after the first step, at least one spacer may be formed on the first electrode.

Another feature of the present invention is a dry etching method using any one of a laser beam, an ion beam, and a plasma. In addition, in the case of etching using plasma, the second electrode is formed and then a planarization process is added.

According to the present invention, since the shadow mask and the dry etching method are used, the manufacturing method of the organic electroluminescent display panel is simple and the production yield can be increased.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

A preferred embodiment of the method of manufacturing an organic electroluminescent display panel according to the present invention will be described with reference to the accompanying drawings.

First, as shown in FIG. 5A, the first electrode pattern and the pad pattern 502 are formed on the transparent substrate 501, and then a buffer layer 503 is formed on the transparent substrate 501.

Here, an organic material or an inorganic material may be used as the buffer layer 503, for example, photoresist, silicon oxide, silicon nitride, or the like.

As shown in FIG. 5B, the buffer layer may be spin coated, a doctor blade method, a thermal evaporation method, an e-beam evaporation method, a sputtering method. , Chemical vapor deposition, or the like.

As shown in FIG. 5B, the first electrode 502 is exposed by etching the buffer layer 503 on the pad connection portion and the portion to be the light emitting pixel.

Subsequently, at least one spacer may be formed.

Here, the spacer is formed of an organic material or an inorganic material, for example, formed of any one of photoresist, silicon oxide, and silicon nitride.

As shown in FIG. 5C, the red organic emission layer 504 is formed using the first shadow mask 505.

Subsequently, as shown in FIGS. 5D and 5E, the green shadow layer 506 and the blue organic emission layer 508 are sequentially formed while moving the first shadow mask 505.

At this time, organic or inorganic substances commonly required for each pixel may be formed simultaneously, for example, a charge injection layer and a charge transport layer.

As shown in FIG. 5F, after the formation of the organic emission layer is finished, the second electrode 511 is deposited using the second shadow mask 510.

Since the second electrode 511 formed as above may have an electrical short between adjacent electrodes, the pixel is separated using a dry etching method.

As the dry etching method, a laser beam, an ion beam, a plasma, or the like can be used.

In the case of etching using plasma, the planarization process is further performed after forming the second electrode, and the organic or inorganic material is coated for the planarization process.

6 is a process plan view of an organic electroluminescent display panel according to the present invention, illustrating a dry etching method.

As shown in FIG. 6, the second electrode is dry-etched in the A-A 'direction.

Finally, a protective film made of oil and inorganic is coated on the device, and the device is sealed in an inert gas atmosphere.

The organic electroluminescent display panel according to the present invention as described above has the following effects.

First, it does not use a photolithography process, so it is not affected by solvents that are lethal to the device.

Second, since the partition wall process can be omitted, the process is simple, productivity is improved, and the defective rate can be significantly reduced.

Third, by using the dry etching method, the etching width or depth can be adjusted, and large area panels can be processed simply and quickly.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (10)

In the manufacturing method of an organic electroluminescent display panel having a first electrode and a second electrode formed on a transparent substrate and a plurality of pixels consisting of at least one organic light emitting layer formed therebetween, A first step of forming a first electrode on the substrate; A second step of sequentially forming at least one organic light emitting layer on the first electrode by using a first shadow mask; A third step of forming a second electrode on the organic light emitting layer by using a second shadow mask; And a fourth step of patterning the second electrode for electrical insulation between the adjacent pixels by a dry etching method. The method of claim 1, After the first step, forming at least one spacer on the first electrode. The method of claim 2, The spacer is an organic electroluminescent display panel manufacturing method, characterized in that formed of an organic or inorganic material. The method of claim 2, The spacer is an organic electroluminescent display panel manufacturing method characterized in that formed of any one of photoresist, silicon oxide, silicon nitride. The method of claim 1, After the first step, forming an electrically insulating buffer layer on the first electrode. The method of claim 5, The buffer layer is an organic electroluminescent display panel manufacturing method characterized in that formed of any one of photoresist, silicon oxide, silicon nitride. The method of claim 5, The buffer layer may be spin coated, a doctor blade method, a thermal evaporation method, an e-beam evaporation method, a sputtering method, or a chemical vapor deposition method. The organic electroluminescent display panel manufacturing method characterized in that it is formed by any one of the) method. The method of claim 1, The dry etching method is an organic electroluminescent display panel manufacturing method using any one of a laser beam, an ion beam, plasma. The method of claim 8, In the case of etching using the plasma, after the forming of the second electrode, further comprising the step of performing a planarization process of the organic electroluminescent display panel. The method of claim 9, Organic electroluminescent display panel manufacturing method characterized in that for coating the organic or inorganic material for the planarization process.