KR100498006B1 - Fabricating method of organic electroluminescence device - Google Patents

Abstract

The present invention relates to a method for manufacturing an organic electroluminescent device, and more particularly, to a method for manufacturing an organic electroluminescent device for forming an auxiliary electrode by using a lift-off method. By using the method of the present invention, it is possible to prevent damage to the ITO layer due to the formation of the conventional auxiliary electrode, to form an auxiliary electrode pattern for full color light emission, and to reduce the manufacturing cost of the shadow mask.

Description

Fabrication method of organic electroluminescence device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an organic electroluminescence device (OELD), hereinafter referred to as an " organic EL device ", and more particularly to an auxiliary electrode using a lift-off method. The manufacturing method of the organic electroluminescent element to form.

In recent years, as the size of a display device (display) increases, the demand for a flat display device having less space is increasing. As a display capable of solving such a problem, an organic EL device using an organic light emitting material has recently attracted much attention.

The organic EL device has advantages such as low voltage driving, self-luminous, high luminous efficiency, light weight, wide viewing angle and fast response speed. This is actively going on.

Organic electroluminescence is recombination of electrons and holes injected through a cathode and an anode into an organic (low molecular or polymer) thin film to form an exciton, and specified by energy from the excitons formed. It is a phenomenon that light of wavelength is generated.

The organic EL device using this phenomenon has a basic structure as shown in FIG. 1 is a schematic view showing a conventional organic EL device.

The basic configuration of the organic EL device is, as shown in FIG. 1, on the transparent substrate 1, the anode electrodes 2 arranged in a stripe shape on the transparent substrate 1, and on the anode electrodes 2. The stacked organic electroluminescent layer 3 and the metal electrode, which is a cathode electrode 4 formed in a band shape and intersecting with the anode electrode on the organic electroluminescent layer 3, are sequentially stacked.

The organic electroluminescent layer 3 includes a hole transport layer (3B) for transporting holes injected from the anode electrode 2 to the light emitting layer; A light emitting layer (3C), which is a region where light is emitted while recombination of holes and electrons supplied from the anode electrode 2 and the cathode electrode 4 is performed; And an electron transport layer (3D) for sequentially transporting electrons supplied from the cathode electrode 4 in a stacked manner. In some cases, a hole injection layer and an electron injection layer may be further stacked to smoothly inject holes and electrons into the device.

An organic EL device having such a structure is manufactured through the following steps.

First, a transparent electrode for an anode is deposited on a transparent glass substrate using a vacuum deposition method, and patterned by photolithography.

Herein, indium tin oxide (ITO, hereinafter referred to as “ITO”) in which indium oxide (In ₂ S ₃ ) is doped with tin oxide (SnO ₂ ) is suitable as a metal satisfying the permeability as an anode electrode. This ITO has a problem of high resistance, and the resistance of the ITO acts as a factor that greatly affects the characteristics of the organic EL device.

Therefore, as a method for stabilizing the ITO layer, that is, lowering the resistance of the ITO layer, a method of forming an auxiliary metal electrode on an edge of the ITO layer is used. That is, a metal material layer is deposited on the patterned ITO layer, and then patterned by photolithography to form an auxiliary dry electrode.

Next, an insulating wall and a partition wall are formed by a photolithography method on the ITO layer on which the auxiliary electrode is formed. Thereafter, the organic material layer described above is deposited, and the metal electrode for the cathode electrode is entirely deposited on the organic material layer.

The process of forming the ITO layer and the metal auxiliary electrode described above will be described in more detail with reference to FIGS. 2 and 3 as follows. 2 illustrates a method of firstly forming an ITO layer and then forming an auxiliary electrode, and FIG. 3 illustrates a method of simultaneously patterning an auxiliary electrode and an ITO layer.

Referring to FIG. 2, first, an ITO layer is entirely deposited on a glass substrate 12, and patterned into a stripe having a predetermined interval by photolithography (FIG. 2A). Cr, Mo, and the like are entirely deposited on the patterned anode electrode 14 with the auxiliary electrode material (FIG. 2B), and the photoresist 18 is applied on the metal layer 16 (FIG. 2C). After performing the exposure process (FIG. 2D), the image development process (FIG. 2E), and the etching process (FIG. 2F) with respect to the metal layer using the photomask P sequentially, it removes the residual photoresist pattern 18A, and FIG. As shown, a patterned auxiliary metal electrode 16A is formed on the patterned ITO layer 14.

Referring to FIG. 3, first, an ITO layer 24 is entirely deposited on the glass substrate 22 (FIG. 2A), and the auxiliary electrode material is sputtered by using a shadow mask. ) Is formed (FIG. 3B). The negative photoresist 28 is entirely coated on the ITO layer 24 on which the auxiliary electrode 26 is formed (FIG. 3C). An ITO layer 24A patterned as shown in FIG. 3F by performing an exposure process (FIG. 3D) and a developing process (FIG. 3E) using a photomask P, and an etching process for the auxiliary electrode and the ITO layer. A patterned auxiliary metal electrode 26A is formed on the.

However, as shown in FIG. 2, when the auxiliary electrode is deposited without using the shadow mask, the auxiliary electrode material is applied to the active site of the ITO layer for stacking the organic electroluminescent layer when sputtering the auxiliary electrode material, thereby damaging the ITO layer. This causes a fatal defect in the organic EL device.

In addition, as shown in FIG. 3, even when the auxiliary electrode is formed by using the shadow mask, a significant masking technique is required in order to use the shadow mask while the substrate becomes large, and shadows are formed by heat during sputtering of the auxiliary electrode material. Due to the distortion of the mask, a phenomenon in which the auxiliary electrode material penetrates to the active site of the ITO (hereinafter referred to as "shadow phenomenon") occurs and damages the ITO layer.

Therefore, there is a need for a method of forming an auxiliary electrode that lowers the resistance of the ITO layer but does not affect the ITO layer.

Accordingly, the present inventors have intensively studied to solve the above problems, and as a result, the lift-off method, which is a method of forming an electrode in a semiconductor process when forming an auxiliary electrode, is applied to a process of an organic EL device. When applied, it has been confirmed that the shadow phenomenon of the auxiliary electrode material can be completely prevented, and thus the present invention has been completed.

Therefore, the present invention has been made to solve the problems of the prior art, an organic EL device for forming an auxiliary electrode using a lift-off method, which can prevent the damage of the ITO layer by forming a conventional auxiliary electrode The purpose of the preparation method.

In order to achieve the above object, the present invention comprises the steps of forming a stripe-shaped first electrode on a transparent substrate; Forming an auxiliary electrode on the first electrode by a lift-off method; Forming an organic emission layer on the first electrode; And it provides a method of manufacturing an organic electroluminescent device comprising the step of forming a second electrode on the organic light emitting layer.

In the method for manufacturing an organic EL device of the present invention, the lift-off method for forming the auxiliary electrode includes the steps of: depositing a photoresist on the first electrode patterned in a stripe shape; Exposing a predetermined portion using a photomask; Developing the exposed photoresist; Depositing a metal layer for forming an auxiliary electrode on the developed photoresist; And selectively removing unnecessary metal layer portions that do not form residual photoresist and auxiliary electrodes.

In the method for manufacturing the organic EL device of the present invention, the lift-off method for forming the auxiliary electrode further comprises: depositing a photoresist on the entire surface of the first electrode on the substrate; Exposing a predetermined portion using a photomask; Developing the exposed photoresist; Depositing a metal layer for forming an auxiliary electrode on the developed photoresist; Selectively removing portions of the unnecessary metal layer that do not form residual photoresist and auxiliary electrodes; And etching the first electrode in a stripe form.

Other objects and features of the present invention in addition to the above object will become more apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, the present invention will be described in detail through the description of a preferred embodiment through the drawings.

First embodiment

FIG. 4 is a diagram illustrating each step of forming an auxiliary electrode according to a first embodiment of the present invention, and the auxiliary electrode forming process according to the first embodiment will be described below.

First, an ITO layer is deposited on the glass substrate 102 by using a vacuum deposition method, and patterned into a stripe having a predetermined interval by photolithography (FIG. 4A). Photoresist 106 is entirely deposited on patterned ITO layer 104 (FIG. 4B). Then, the exposure process (FIG. 4C) and the image development process (FIG. 4D) using the photomask P are performed sequentially. Molybdenum (Mo) is then applied to the entire surface to form an auxiliary electrode layer between the unexposed remaining photoresist (FIG. 4E). Thereafter, unnecessary portions of the remaining photoresist pattern 106A and the auxiliary electrode are removed at the same time.

As shown in FIG. 4F, the generated auxiliary electrode 108A has no influence on the active site of the ITO layer 104 for stacking the organic light emitting layer.

Second embodiment

FIG. 5 is a diagram illustrating each step of forming the auxiliary electrode according to the second embodiment of the present invention, and the auxiliary electrode forming process according to the second embodiment will be described below.

First, an ITO layer is deposited on the glass substrate 202 by vacuum deposition, and a photoresist 206 is deposited on the ITO layer 204 (FIG. 5B). Then, the exposure process (FIG. 5C) and the image development process (FIG. 5D) using the photomask P are performed sequentially. Molybdenum (Mo) is then applied to the entire surface to form an auxiliary electrode layer between the unexposed remaining photoresist (FIG. 5E). Thereafter, unnecessary portions of the photoresist pattern 206A and the auxiliary electrode are removed, and the ITO layer is also etched away.

As shown in FIG. 5F, the generated auxiliary electrode 208A has no influence on the active site of the ITO layer 204A for stacking the organic light emitting layer.

By using the method of the present invention as described above it is possible to prevent the damage of the ITO layer according to the conventional auxiliary electrode formation can be produced a stable organic EL device, it is easy to form the auxiliary electrode pattern for full color light emission, shadow The manufacturing cost of the mask can be reduced.

1 is a schematic view showing a conventional organic electroluminescent device.

2A to 2G are cross-sectional views illustrating each step of forming an ITO layer and a metal auxiliary electrode according to a conventional example.

3A to 3F are cross-sectional views illustrating respective steps of forming an ITO layer and a metal auxiliary electrode according to another example of the related art.

4A to 4F are cross-sectional views showing respective steps of forming an ITO layer and a metal auxiliary electrode according to a first embodiment of the present invention.

5A to 4F are cross-sectional views illustrating respective steps of forming an ITO layer and a metal auxiliary electrode according to a second embodiment of the present invention.

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

1, 12, 22, 102, 202: transparent substrate 2, 14, 24, 104, 204: anode electrode

3: organic electroluminescent layer 4: cathode electrode

16, 26, 108, 208: auxiliary electrode 18, 28, 106, 206: photoresist

Claims (3)

delete Forming a stripe-shaped first electrode on the transparent substrate; Depositing photoresist on the first electrode patterned in the form of a stripe; Exposing a predetermined portion using a photomask; Developing the exposed photoresist; Depositing a metal layer for forming an auxiliary electrode on the developed photoresist; Selectively removing portions of the unnecessary metal layer that do not form residual photoresist and auxiliary electrodes; Forming an organic emission layer on the first electrode; And A method of manufacturing an organic electroluminescent device comprising forming a second electrode on the organic light emitting layer. Depositing a first electrode on the transparent substrate; Depositing a photoresist on the first electrode which is deposited on the substrate; Exposing a predetermined portion using a photomask; Developing the exposed photoresist; Depositing a metal layer for forming an auxiliary electrode on the developed photoresist; Selectively removing portions of the unnecessary metal layer that do not form residual photoresist and auxiliary electrodes; Etching the first electrode in the form of a stripe Forming an organic emission layer on the first electrode; And A method of manufacturing an organic electroluminescent device comprising forming a second electrode on the organic light emitting layer.