KR100606444B1 - Method for fabricating an eld - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electroluminescent device, in order to fabricate an ELD capable of preventing a pattern defect of an organic EL layer and achieving high resolution, a pixel cell defined by scan lines and signal lines, a scan line and Providing a substrate including a switching element formed to be electrically connected to a signal line, forming a protective layer covering an entire surface of the substrate, and forming a contact hole exposing one electrode of the switching element in the protective layer; Forming an anode layer of the organic EL portion connected to one electrode of the exposed switching element, and forming an organic EL layer of the organic EL portion on the exposed entire surface of the substrate including the anode layer. A first step of continuously forming a metal layer for forming a cathode layer of the EL portion, and laser exposure of the metal layer and the organic layer And the second step of selectively removing the cathode layer and the organic EL layer by forming the EL layer, and forming the EL portion by using a laser, thereby causing a pattern defect of the organic EL portion caused by a conventional technique using a shadow mask. It is possible to prevent the formation of a fine pattern, it is possible to manufacture a high-definition product.

Electroluminescent device manufacturing method

Description

Manufacturing method of electroluminescent device {METHOD FOR FABRICATING AN ELD}

1a to 1d is a manufacturing process of the electroluminescent device according to the prior art

2a to 2h is a first embodiment of the manufacturing process of the electroluminescent device according to the present invention

3A to 3H illustrate a second embodiment of a manufacturing process of an electroluminescent device according to the present invention.

The present invention relates to a method of manufacturing an electroluminescent display (ELD), and more particularly, to a method of manufacturing an active electroluminescent device using an organic light emitting material.

ELD is a device that injects electrons and holes from the outside, recombines electrons and holes, generates excitation molecules, and emits light of these excitation molecules, which does not require a backlight, thereby reducing the thickness of the panel. As power consumption can be lowered relatively, attention is focused on the next generation display.

In particular, an organic ELD using an organic EL (ElectroLuminescence) material to form a light emitting layer, that is, an EL layer, requires (1) a low voltage to emit an organic EL cell, and (2) a high luminous efficiency of the organic EL cell. (3) It has the advantage of being able to carry out low temperature manufacturing process.

However, since the organic EL material cannot be subjected to the existing photolithography process because it is damaged by moisture, a pattern is formed by a method not in direct contact with moisture.

The active ELD has a structure in which a plurality of scan lines and signal lines cross each other to form a plurality of pixel cells, and in each pixel cell, a powder supply line is arranged in the same direction as the signal line. Each pixel cell includes one or more switching elements, for example, TFTs, and includes a storage capacitor and an EL portion.

In the case of using two TFTs, the EL excitation signal and the scanning signal can be distinguished from each other. The EL portion is selected by the logic TFT, and the excitation power of the EL portion is adjusted by the powder of another TFT.

The storage capacitor functions to maintain the excitation power of the EL portion of the selected cell.

1A to 1D schematically illustrate a manufacturing process of an ELD according to the prior art.

Referring to FIG. 1A, a substrate having a pixel cell defined by a scan line and a signal line and a TFT formed on each of the pixel cells, the TFTs being electrically connected to the scan line and the signal line, is provided on the insulating substrate 100. A protective film 110 is formed to cover the exposed front surface of the substrate. This step may be performed in the same manner as a display manufacturing step having a normal TFT.

Referring to FIG. 1B, the protective layer 110 is photo-etched to form contact holes that expose one electrode of the TFTs, respectively. Subsequently, a layer of transparent conductive material is deposited on the entire surface of the substrate and photo-etched to form anode layers 11-1, 11-2, and 11-3 which are separated from each other in each pixel cell. .

Referring to Figure 1c, using a shadow mask (shadow mask), through the evaporation (evaporation) deposition technique (evaporation) is positioned on top of the anode layer (11-1) (11-2) (11-3), respectively, . The organic EL layers 12-1, 12-2, and 12-3 that give a predetermined color, for example, red, green, and blue, are formed.

Referring to FIG. 1D, a cathode layer 13, which is a common electrode covering an exposed front surface of a substrate, is formed, and a cover layer 14 covering an entire surface of the cathode layer 13 is formed.

As mentioned, since the conventional photolithography process cannot be used in the fabrication of ELD according to the prior art, organic EL materials are directly deposited on the anode layer by shadow mask and evaporation techniques. Form a layer.

However, the adhesion of the shadow mask onto the substrate is not perfect, and a misalignment of the shadow mask and the substrate occurs, resulting in a problem of poor pattern of the organic EL layer. In addition, since the organic EL material is deposited on the substrate through an evaporation deposition technique using a shadow mask adhered to the substrate, the shadow mask is stretched by its load, and thus there is a limitation in implementing high resolution.

An object of the present invention is to provide a method for manufacturing an ELD that can solve the problems according to the prior art.                         

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing an ELD capable of preventing a pattern defect of an organic EL layer and achieving high resolution.

The present invention provides a process for providing a substrate having a pixel cell defined by a scan line and a signal line, and a switching element formed on the pixel cell to be electrically connected to the scan line and the signal line, and a protective film covering the entire surface of the substrate. Forming a contact hole for exposing one electrode of the switching element to the passivation layer, forming an anode layer of an organic EL portion connected to the exposed electrode of the switching element, and the anode layer A first step of successively forming an organic layer for forming an organic EL layer of the organic EL portion and a metal layer for forming a cathode layer of the organic EL portion on the exposed entire surface of the substrate comprising a, and the metal layer and the organic layer for laser exposure Method of manufacturing an electroluminescent device comprising a second step of selectively removing by forming the cathode layer and the organic EL layer It provides.

In addition, the present invention provides a process for providing a substrate having a pixel cell defined by a scan line and a signal line, and a switching element formed on the pixel cell to be electrically connected to the scan line and the signal line, and a protective film covering the entire surface of the substrate. Forming a contact hole for exposing one electrode of the switching element to the passivation layer, forming an anode layer of an organic EL portion connected to the exposed electrode of the switching element, and the anode layer A first step of forming an organic layer for forming an organic EL layer of the organic EL portion on an exposed entire surface of the substrate including a second step; and a second process of selectively removing the organic layer by laser exposure to form the organic EL layer; It provides a method of manufacturing an electroluminescent device comprising the step of forming a cathode layer of the organic EL portion on the organic EL layer.

Hereinafter, the present invention will be described with reference to the following examples and accompanying drawings.

The present invention is characterized in that the organic EL layer and the cathode layer are patterned through laser exposure, instead of using a shadow mask, which is a cause of pattern defect of the organic EL layer and a limitation in realizing high resolution.

Since the laser light is a single light, (1) the monochromatic property, which is a property of approaching a single pure frequency, that is, one frequency, is excellent, and (2) the directivity is such that the light does not spread and goes straight in a constant direction. , (3) It has excellent coherence, which shows the pattern of contrast according to the phase difference when it hits an obstacle. (4) When condensing with a lens due to high energy concentration and brightness, the temperature of the focusing point is 1 million depending on the laser type. It can even lead to

In the ELD according to the present invention, the EL portion, which is a light emitting region, will be described with reference to FIG. 2H. The EL portion is a transparent conductive layer 26-1 (26-2) (26-3), which is an anode, on the protective film 210. The organic EL layers 27-1, 27-2 and 27-3 and the cathode metal layers 28-1, 28-2 and 28-3 are laminated. An anode transparent conductive layer is formed separately for each pixel cell so as to be formed independently in each pixel cell. The organic EL layer is also formed separately for each pixel cell so as to be formed independently in each pixel cell. The cathode metal layer, which is the upper layer of the EL portion, is used as a common electrode, and thus is formed on the entire surface of the substrate so as to cover each pixel cell.

The metal layer used as the cathode is formed using metal materials having low work functions such as potassium, sodium, calcium and lithium.

The organic EL layer has a hole injecting and transporting region in contact with the anode layer and an electron injecting and transporting region constituting it.

The hole injection and transport region may be formed of a single material or multiple materials, and includes a hole injection region in contact with the anode layer and a hole transport region located between the hole injection region and the electron injection and transport region.

The electron injection and transport region may also be formed of a single material or multiple materials, and has an electron injection region in contact with the cathode and an electron transport region located between the electron injection region and the hole injection and transport region.

The recombination of electrons and holes causes light emission near the section of the hole injection and transport region and the electron injection and transport region.

As such, each light generated in the organic EL layers 27-1, 27-2, and 27-3 is viewed through the anode layers 26-1, 26-2, and 26-3, which are transparent conductive layers. Will be shown.

2A to 2E show a first embodiment of an ELD manufacturing process according to the present invention.

Referring to FIG. 2A, a passivation layer may include a substrate including a pixel cell defined by a scan line and a signal line, and a TFT formed in each pixel cell, the TFT being electrically connected to the scan line and the signal line, and covering the exposed front surface of the substrate. 210). This step may be performed in the same manner as a display manufacturing step having a normal TFT.

When providing a substrate using the bottom gate type TFT as a switching element, the substrate can be manufactured by the following process.

A gate electrode 21 is formed on the insulating substrate 200, and a gate insulating film 22 covering the entire surface of the substrate is formed. Subsequently, the semiconductor layer 23, which is an active region of the switching element, and the impurity semiconductor layer 24, which is an ohmic contact layer, are formed on the gate insulating layer 22 on the gate electrode 21. Then, a signal line is formed on the gate insulating layer 22 and the source electrode 25S and the drain electrode 25D electrically connected to the semiconductor layer 23, and are exposed between the source electrode 25S and the drain electrode 25D. The impurity semiconductor layer portion is removed.

The insulating substrate 200 may use a crystalline material such as quartz or glass.

The gate electrode 21 may be formed by depositing a conventional conductive layer on the insulating substrate 200 to a thickness of 2000 to 4000 microns, and then etching the photo. In this case, a scan line connected to the gate electrode 21 may also be formed.

The gate insulating film 22 can be formed by depositing a silicon oxide film or a silicon nitride film with a thickness of 3000 to 5000 kV through a conventional insulating film deposition technique.

The semiconductor layer 23 and the impurity semiconductor layer 24 are successively deposited on the gate insulating film 22 by depositing an amorphous silicon layer and an impurity amorphous silicon layer at a thickness of 1500 to 2500 ∼ and 200 to 500 각각, respectively, followed by photolithography. Can be formed. In this case, the amorphous silicon layer and the impurity amorphous silicon layer may be crystallized and then formed by photolithography.

The source electrode 25S and the drain electrode 25D may be formed by depositing a conventional conductive layer with a thickness of 1500 to 3000 GPa on the exposed entire surface of the substrate and then etching the photo. In this case, signal lines connected to the source electrodes 25S may be simultaneously formed.

The protective film 210 may be formed by depositing a silicon oxide film or a silicon nitride film with a thickness of 2500 to 4000 microns through a conventional insulating film deposition technique.

When the passivation layer 210 is formed of an organic material such as BCB (BenzoCycloButane) or SOG (Spin On Glass), the protective layer 210 may be formed slightly thicker to cover the substrate. As such, when the protective film 210 is formed flat, defects caused by steps may be reduced during the subsequent process, for example, the process of forming the EL part, and the dielectric constant is low on the signal line and the powder supply line. The organic film is interposed to reduce the coupling effect that can occur between the wirings, which is advantageous in that good image quality can be obtained.

Referring to FIG. 2B, the protective film 210 is photo-etched to form a contact hole exposing a part of the drain electrode 25D of each TFT, and then the anode layer 26-of the organic EL portion connected to the drain electrode 25D. 1) 26-2 and 26-3 are formed, respectively. The anode layer connected to the drain electrode is formed to be separated from each other in each pixel cell because the signal must be independently transmitted to each pixel cell.

For convenience of description, the anode layers positioned on the first, second, and third pixel cells are defined as first, second, and third anode layers 26-1, 26-2, and 26-3, respectively. do.

The anode layer may be formed by depositing a conventional transparent conductive layer on the entire surface of the substrate to a thickness of 700 to 1500 kPa.

Referring to FIG. 2C, the first organic layer EL1 for forming an organic EL layer capable of emitting a first emission color and the first metal layer ML1 for forming a cathode layer are sequentially deposited on the exposed entire surface of the substrate. do.

Referring to FIG. 2D, the first metal layer ML1 and the first organic layer EL1 may be selectively removed through laser exposure, and the first organic EL layer 27-1 may be formed on the first anode layer 26-1. The first cathode layer 28-1 is formed. At this time, the energy density of the laser is adjusted to remove only the first metal layer ML1 and the first organic layer EL1.

First patterning of the first cathode layer 28-1 with a laser having a first energy, and then patterning the first organic EL layer 27-1 with a laser having a second energy, or using a third energy A method of simultaneously patterning the first cathode layer 28-1 and the first organic EL layer 27-1 with a laser having?

In this case, the first organic EL layer 27-1 and the first cathode layer 28-1 may be formed by performing selective exposure of the laser only by the movement of the substrate without using a separate pattern mask.

The present invention has an advantage that the organic EL layer can be stably formed because the photolithography process that requires moisture and high temperature baking is not performed. In addition, in the process of patterning the organic EL layer, a fine pattern may be formed since the laser light having a high resolution characteristic is directly irradiated to the organic layer without using a separate pattern mask, for example, a shadow mask.

Referring to FIG. 2E, the second organic layer EL2 for forming an organic EL layer capable of emitting a second emission color on the exposed entire surface of the substrate and the second metal layer ML2 for forming a cathode layer are sequentially deposited. do.

Unexplained reference numeral 20 denotes an interface between the first cathode layer 28-1 and the second metal layer ML2.

Referring to FIG. 2F, only the second metal layer ML2 and the first organic layer EL2 may be selectively removed through laser exposure, and the second organic EL layer 27-2 may be disposed on the second anode layer 26-2. The second cathode layer 28-2 is formed.

At this time, the energy density of the laser is adjusted to remove only the second metal layer ML2 and the second organic layer EL2.

The side boundary surface 20 of the first cathode layer 28-1 and the second metal layer ML2 may be the side boundary surface of the first cathode layer 28-1 and the second cathode layer 28-2. The second metal layer ML2 and the second organic layer EL2 may be selectively removed. In this case, the first cathode layer 28-1 is connected to the second cathode layer 28-2.

In the process of patterning the second organic layer ML2, the first cathode layer 28-1 functions as a barrier to protect the first organic EL layer 27-1.

As can be seen from the above, the process of forming the second organic EL layer 27-2 and the second cathode layer 28-2 is performed by the first organic EL layer 27-1 and the first cathode layer 28-1. In the same manner as the step of forming a).

Referring to FIG. 2G, the first organic EL layer 27-1 and the first cathode layer 28-1 or the second organic EL layer 27-2 and the second cathode layer 28-2 are formed. The same operation as that described above is performed to form the third organic EL layer 27-3 and the third cathode layer 28-3 on the third anode layer 26-3.

The third organic EL layer 27-3 can be formed using a third organic layer capable of emitting a third light emission color.

The first, second and third metal layers for forming the cathode layer of the organic EL portion may be formed by depositing a metal layer having a low work function, such as potassium, sodium, calcium, and lithium, at a thickness of 1500 to 2500 GPa.

The cathode layers 28-1, 28-2, and 28-3 formed on the pixel cells are formed to be connected in common, as shown in the drawing, or the cathode layers are controlled by adjusting the exposure range of the laser. (28-1) (28-2) (28-3) can be formed separately.

Referring to FIG. 2H, the cathode layer 28-1 is deposited by depositing a conventional metal layer such as Al on the exposed front surface of the substrate including the respective cathode layers 28-1, 28-2, and 28-3. 28-2 and 28-3 to form a common electrode 29 in common.

If the cathode layers 28-1, 28-2, and 28-3 are already connected in common, the formation of the common electrode 29 can be omitted.

Thereafter, the cover layer 220 covering the exposed front surface of the substrate is formed.

3A to 3G show a second embodiment of the ELD manufacturing process according to the present invention.

The second embodiment of the ELD manufacturing process according to the present invention proceeds similarly to the first embodiment of the present invention. That is, instead of simultaneously forming the organic EL layer and the cathode layer, first, the organic EL layer is formed for each pixel cell, and then the cathode layer is formed with a common electrode covering each organic EL layer in common.

Referring to FIG. 3A, a passivation layer may include a substrate including a pixel cell defined by a scan line and a signal line, and a TFT formed in each pixel cell, the TFT being electrically connected to the scan line and the signal line, and covering an exposed front surface of the substrate. 310). This step may be performed in the same manner as a display manufacturing step having a normal TFT.

The protective film 310 is then etched to form a contact hole exposing a part of the drain electrode 35D of each TFT, and then the anode layer 36-1 of the organic EL portion connected to the drain electrode 35D ( 36-3) and 36-3 respectively. The anode layer connected to the drain electrode is formed to be separated from each other in each pixel cell because the signal must be independently transmitted to each pixel cell.

For convenience of description, the anode layers positioned on the first, second and third pixel cells are defined as first, second and third anode layers 36-1, 36-3, and 36-3, respectively. do.

Referring to FIG. 3B, an organic EL layer capable of emitting a first emission color on the exposed front surface of the substrate including the first, second, and third anode layers 36-1, 36-2, and 36-3. The first organic layer EL1 is formed to form a film.

Referring to FIG. 3C, the first organic layer EL1 is selectively removed through laser exposure to form a first organic EL layer 37-1 on the first anode layer 36-1.

At this time, the energy density of the laser is adjusted to remove only the first organic layer EL1.

Referring to FIG. 3D, a second organic layer EL2 is formed on the exposed front surface of the substrate including the first organic EL layer 37-1 to form an organic EL layer capable of emitting a second emission color.

Referring to FIG. 3E, the second organic layer EL2 is selectively removed through laser exposure to form a second organic EL layer 37-2 on the second anode layer 36-2.

At this time, the energy density of the laser is adjusted to remove only the second organic layer EL2.

The side boundary surface 30 of the first organic EL layer 37-1 and the second organic layer EL2 may be the side boundary surface of the first organic EL layer 37-1 and the second organic EL layer 36-2. It is possible to selectively remove the second organic layer (EL2).

As can be seen from the above, the process of forming the second organic EL layer 37-2 proceeds in the same manner as the process of forming the first organic EL layer 37-1.

Referring to FIG. 3F, the same operation as that of forming the first organic EL layer 37-1 or the second organic EL layer 37-2 is performed to form the third organic layer on the third anode layer 36-3. Three organic EL layers 37-3 are formed.

The third organic EL layer 37-3 can be formed using a third organic layer capable of emitting a third light emission color.

As shown in the drawing, the organic EL layers 37-1, 37-2, and 37-3 formed in the pixel cells are formed to be connected in common, or the organic EL layers 37-1, 37-2, and 37-3 are controlled by controlling the exposure range of the laser. The EL layers 37-1, 37-2 and 37-3 can be formed separately.

Referring to FIG. 3G, the cathode layer 38 is formed by depositing a cathode layer forming metal layer on an exposed front surface of the substrate including each of the organic EL layers 37-1, 37-2, and 37-3. do. The cathode layer 38 becomes a common electrode which covers each of the organic EL layers 37-1, 37-2 and 37-3 in common.

Thereafter, a cover layer 320 is formed to cover the exposed front surface of the substrate.

The present invention may be embodied in various embodiments through the appended claims and the detailed description, as well as the embodiments shown, and may be applied in various ways by partners.

Since the present invention forms the EL portion using a laser, it is possible to prevent a pattern defect of the organic EL portion caused by a conventional technique using a shadow mask, and to form a fine pattern by forming a fine pattern. . In addition, since the organic EL layer is patterned by directly irradiating a laser, the manufacturing process can be simplified.

Claims (10)

Providing a substrate having a pixel cell defined by a scan line and a signal line, and a switching element formed on the pixel cell to be electrically connected to the scan line and the signal line; Forming a protective film covering the entire surface of the substrate; Forming a contact hole exposing one electrode of the switching element in the passivation layer; Forming an anode layer of the organic EL portion connected to one electrode of the exposed switching element; A first step of continuously forming an organic layer for forming an organic EL layer of the organic EL portion and a metal layer for forming a cathode layer of the organic EL portion on an exposed entire surface of the substrate including the anode layer; And removing the metal layer and the organic layer selectively by laser exposure to form the cathode layer and the organic EL layer. The method according to claim 1, The pixel cells are divided into first, second, and third types on the substrate, and are defined in plural numbers to form a switching element and an anode layer in each of the pixel cells. The second process is performed from the first process, but the cathode layer and the organic EL layer of the first pixel cell are first formed, and then the second process is repeated from the first process to the cache of the second pixel cell. A method of manufacturing an electroluminescent device, which sequentially forms a cathode layer and an organic EL layer, and a cathode layer and an organic EL layer of the third type pixel cell. The method of claim 2, The method of manufacturing an electroluminescent device for laser patterning to connect the cathode layers in common. The method of claim 2, And forming a common electrode covering the exposed front surface of the substrate including the cathode layers. The method according to claim 3 or 4, The method of manufacturing an electroluminescent device further comprising the step of forming a cover layer on the entire exposed surface of the substrate. The method according to claim 1 or 2, The method of manufacturing an electroluminescent device for performing laser exposure by adjusting the energy density of the laser to remove only the metal layer or the organic layer. Providing a substrate having a pixel cell defined by a scan line and a signal line, and a switching element formed on the pixel cell to be electrically connected to the scan line and the signal line; Forming a protective film covering the entire surface of the substrate; Forming a contact hole exposing one electrode of the switching element in the passivation layer; Forming an anode layer of the organic EL portion connected to one electrode of the exposed switching element; A first step of forming an organic layer for forming an organic EL layer of an organic EL portion on an exposed entire surface of the substrate including the anode layer; A second step of forming the organic EL layer by selectively removing the organic layer by laser exposure; A method of manufacturing an electroluminescent device comprising the step of forming a cathode layer of an organic EL portion on the organic EL layer. The method of claim 7, wherein The pixel cells are divided into first, second, and third types on the substrate, and are defined in plural numbers to form a switching element and an anode layer in each of the pixel cells. The second process is performed from the first process, but the organic EL layer of the first pixel cell is first formed, and then the second process is repeated from the first process to the organic EL layer of the second pixel cell. An organic EL layer of the third type pixel cell is sequentially formed; A method of manufacturing an electroluminescent device, wherein the cathode layer is patterned so as to cover the first, second and third organic EL layers in common. The method according to claim 7 or 8, The method of manufacturing an electroluminescent device further comprising the step of forming a cover layer on the exposed front surface of the substrate. The method according to claim 7 or 8, The method of manufacturing an electroluminescent device for performing laser exposure by adjusting the energy density of the laser to remove only the organic layer.

Images