JPH11111455A - Manufacture of organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simply manufacturing method for an organic EL (electroluminescent) element having an electrically insulated second electrode of plural belt-like fine pattern, and allowing no short circuit. SOLUTION: A single layer or plural layers of organic layers 4 and second electrode 5 thereon are formed on the whole face of a substrate 1 having barrier ribs 3 formed thereon composed of first electrode 2 comprising plural formed conductors, and plural insulators formed belt-like on the first electrode 2 so as to be orthogonal to the first electrode 2, and organic material and electrode material on the barrier ribs 3 are separated by this method. In the case of the separation of the electrode material and the like on the barrier ribs 3, individual cutting blades are used for the respective barrier ribs. Thereby, the mutually insulated second electrodes 5 are formed into belt-like so as to manufacture an organic EL element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an organic electroluminescent device having an organic layer made of an organic electroluminescent material.

[0002]

2. Description of the Related Art Organic electroluminescent (hereinafter referred to as "organic electroluminescent")
The element has a structure in which a light-emitting layer is sandwiched between a pair of transparent or translucent electrodes (anode and cathode) supported by a substrate. Specifically, (1) anode / light-emitting layer / cathode, (2) anode / hole transport layer / light-emitting layer /
Cathode, (3) anode / light-emitting layer / electron transport layer / cathode, (4)
A configuration having an anode / hole transport layer / light-emitting layer / electron transport layer / cathode is known. If necessary, a hole injection / transport layer or an electron injection / transport layer may be interposed.

By the way, in order to use an organic EL element as a high-density display element, it is indispensable to arrange minute pixels in the form of a matrix in a matrix. For this purpose, fine patterning of electrodes is required. Becomes That is,
By arranging a plurality of strip-shaped anodes and cathodes that are insulated from each other so as to be orthogonal to each other, a portion sandwiched between the two electrodes serves as a light-emitting region, and becomes a pixel. Generally, an indium tin oxide (hereinafter, referred to as ITO) film, which is a transparent electrode, is provided on the side from which light is emitted, and is used as an anode (hereinafter, the first electrode is used as an anode, and the second electrode is used as a cathode). Describe). On top of this, various organic thin films as described above are stacked, and finally a metal having a low work function is deposited as a cathode to obtain an organic EL device.

[0004] A fine pattern can be obtained on the ITO film provided on the supporting substrate by a photolithography method which is a typical fine processing method. Therefore, the problem is the fine patterning of the cathode. First of all,
This is a mask deposition method in which a pattern is formed using a mask when depositing an electrode. However, in this method,
It is very difficult to create a fine pattern, particularly one having a gap between bands of several tens μm or less. That is, the adhesion between the substrate to be deposited and the mask is not sufficiently maintained due to the dripping of the mask, so that the deposited metal wraps around, and sufficient insulation between the strip electrodes cannot be obtained, and a fine pattern of the cathode can be obtained. There is a problem that can not be.

[0005] In addition, a fine processing method by mechanical cutting has been known for a long time, but this method is not suitable for processing a cathode composed of a metal thin film having a considerably low strength, and the electrode processing accuracy is poor. Since it is sufficient, there are drawbacks in that the electrode cannot be completely removed, a short circuit occurs, the underlying ITO may be damaged, and the ITO may be disconnected. JP-A-2-6687
No. 3 discloses that a fine pattern is obtained by a photolithography method similar to that of an anode, but requires a number of steps such as resist coating, baking, exposure, development, etching, and resist stripping. Due to various problems such as deterioration of the electrode material and penetration of moisture into the organic material layer, a practical organic EL device cannot be obtained. A similar wet etching method is also disclosed in JP-A-6-151062.

Japanese Patent Application Laid-Open No. Hei 5-3077 discloses a method of removing a cathode (second electrode) material by thermal processing using a laser beam. However, since the cathode is a mirror surface, it reflects most of the laser light. Therefore, in order to perform thermal processing, it is necessary to use a strong laser. Therefore, heat generated during the processing increases, which adversely affects the light emitting layer and other organic materials. Therefore, Japanese Patent Application Laid-Open No. 9-50888
In Japanese Patent Application Laid-Open Publication No. H10-157, there is a contrivance for weakening the influence of heat by providing a laser protective layer having heat resistance. However, the effect of weakening the influence of heat is small and is not always a satisfactory method.

Japanese Patent Application Laid-Open No. Hei 8-22371 discloses a patterning method using a laser ablation method. However, it is necessary to perform an operation in a vacuum in order to blow scattered metal dust away, and the scattered metal dust is required. However, there is a drawback that the vacuum chamber becomes dirty, and the manufacturing method is not always satisfactory. In Japanese Patent Application Laid-Open No. Hei 5-275172, a partition made of an insulator is provided so as to be orthogonal to a strip-shaped transparent electrode (first electrode) arranged at a predetermined interval, and a cathode (second electrode) is arranged in a direction orthogonal to the partition. A method is disclosed in which an electrode) material is obliquely vapor-deposited, and a strip-shaped negative electrode insulated from each other is provided so that the electrode material does not adhere to a shadow of the partition wall. However, this method has a problem that sufficient insulation cannot be obtained unless the height of the partition walls is considerably increased.

Japanese Patent Application Laid-Open No. 8-315981 discloses a method in which a partition having an overhang portion is provided, an organic layer is deposited while rotating the substrate, and then the rotation of the substrate is stopped to deposit a negative electrode (second electrode). It is shown that the negative electrode is not deposited on the shaded portion of the overhang portion, and an electrically isolated strip-shaped negative electrode is formed. But,
In this method, the cathode can be separated, but there is a problem that the cathode material goes around the shadowed portion and short-circuits with the anode (first electrode) in a portion where the organic layer is not sufficiently laminated.

Japanese Patent Application Laid-Open No. 8-202287 discloses that, similar to Japanese Patent Application Laid-Open No. 5-275172, after forming a partition wall made of an insulator orthogonal to a transparent electrode (first electrode) arranged in a band shape, An organic layer and a negative electrode (second electrode) are vapor-deposited on the entire surface of the substrate from a direction substantially perpendicular to the substrate, and the negative electrode on the partition is removed by a doctor blade or polishing to be electrically isolated at the partition. Thus, a strip-shaped negative electrode can be obtained. However, when the negative electrode is scraped off by polishing, there is a problem that the solvent used at the time of polishing has an adverse effect on the organic layer, and the remaining polishing agent causes uneven emission. Also, in the method of scraping the negative electrode with a doctor blade, if the distance between the blade and the substrate is not set very accurately, the light emitting portion is scraped or uncut, and it is difficult to scrape only the electrode material on the partition walls. . Further, there is a problem that shavings are scattered on the substrate, which causes a short circuit or disconnection.

[0010]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional patterning method of an organic EL device, and comprises a plurality of electrically insulated second electrodes having a strip-like fine pattern. It is an object of the present invention to provide a method for manufacturing an organic EL device having no short circuit.

[0011]

In order to solve the above-mentioned problems, the present invention provides a first electrode layer comprising a plurality of conductors formed on a substrate, and a first electrode layer formed on the first electrode. A single layer or a plurality of organic layers and an electrode layer formed thereon are formed over the entire surface of the substrate on which a plurality of strips made of an insulator are formed in a strip shape so as to be orthogonal to the upper part of the partition. It is a method of peeling the organic layer material and the electrode layer material respectively present, when peeling the electrode material on the partition wall,
Organic E which forms second electrodes insulated from each other in a strip shape by peeling using individual cutting blades for each partition.
This is a method for manufacturing an L element.

The organic EL device of the present invention is preferably supported on a substrate. The substrate is not particularly limited, and those conventionally used in organic EL devices, such as glass, transparent plastic, and quartz, can be used. The electrode and the organic layer configuration of the organic EL device of the present invention include:
(1) anode / light-emitting layer / cathode, (2) anode / hole transport layer /
Any structure such as (3) anode / light emitting layer / electron transporting layer / cathode, (4) anode / hole transporting layer / light emitting layer / electron transporting layer / cathode, etc., which is usually used, may be used. Absent. The organic material of the present invention is a general term for materials used for the organic layer. The light-emitting layer refers to a layer containing a light-emitting material. The light-emitting layer and a layer laminated between an anode and a cathode for other purposes are collectively referred to as an organic layer. In the electrode of the organic EL device of the present invention, when the first electrode is an anode, the second electrode is a cathode, and when the first electrode is a cathode, the second electrode is an anode.

Next, a preferred method for producing the organic EL device of the present invention will be described. As an example, a method for manufacturing an organic EL device comprising the anode / light-emitting layer / cathode of (1) above, in which the anode is the first electrode and the cathode is the second electrode, will be described. First, on a transparent substrate such as glass, The thin film made of the first electrode material is 1 μm or less, preferably 100 to 80 μm.
The first electrode is formed so as to have a thickness of 0 nm by a method such as vapor deposition or sputtering. As the electrode material, an inorganic material such as ITO, ZnO, or CuS or an organic transparent conductive material is used. The patterning of the transparent electrode is performed by conventional fine processing such as lithography.

A strip-shaped insulating partition is formed so as to intersect on the substrate on which the strip-shaped anode is formed. The partition can be formed by a screen printing method, a photolithography method using a photoreactive resin, a mask evaporation method, or the like. As a material of the partition wall, an inorganic material such as an organic polymer material or SiO _x such as a photoresist is used. Next, an organic layer is provided on the substrate on which the strip-shaped first electrode and the partition are formed. As a method of forming the organic layer, for example, a spin coating method, a vapor deposition method, and the like are known, and the methods will be described below.

When the vapor deposition method is adopted, the vapor deposition conditions are as follows:
Generally, the boat heating temperature is 50 to 400 ° C., the degree of vacuum is 10 ⁻⁵ to 10 ⁻³ Pa, and the deposition rate is 0.01 to 50 nm /, although it varies depending on the kind of the organic compound used for the light emitting layer to be used.
Seconds, substrate temperature -50 to + 300 ° C, film thickness 5 nm to 5
It is desirable to select an appropriate value in the range of μm. In the case of employing the spin coating method, the conditions vary depending on the type of the material to be used, the type of the solvent, and the like.
~ 90 parts by weight, spinner rotation speed 100 ~ 100,000
It is desirable to adjust the film thickness to be in the range of 5 nm to 5 μm by the conditions of rotation / minute, substrate temperature of −50 to 300 ° C., and these conditions. Further, after spin coating, the solution is heated at 30 to 400 ° C. for 1 hour in an atmosphere of an inert gas such as nitrogen or argon.
It is desirable to perform heat treatment for 0 minute to 24 hours.

After the formation of the light emitting layer, a thin film made of a substance for a second electrode is formed thereon to a thickness of 1 μm or less by, for example, a method such as vapor deposition or sputtering. Provide. FIGS. 1 and 2 are cross-sectional views of the organic EL device after the formation of the second electrode layer. Figure 1 is ITO
It is sectional drawing of the direction along the electrode. FIG. 2 is a cross-sectional view in a direction orthogonal to the ITO electrodes. In the figure, the ITO electrode is the first electrode and the metal electrode is the second electrode.

In the present invention, a strip-shaped second electrode that is electrically insulated from each other is formed by scraping off the second electrode material on the partition walls. The thickness of both the organic layer and the second electrode layer laminated on the partition walls is 1 μm or less, usually 0.1 to 0.5 μm, which is very thin. When a flat plate such as a glass plate is used as the substrate, there is undulation or warpage of about 0.5 μm, depending on the size, manufacturing method, material and the like of the substrate. Therefore, a single blade such as a doctor blade causes a problem such as uncut or excessively cut as described above. In order to avoid this problem, it is necessary to install small blades in the number of rows so that the blades only hit the partition walls to be cut, and it is preferable to use a comb-shaped cutting tool. Normally, the size of the pixel is 0.1 × 0.1 mm or more, and the distance between the pixels (partition gap) is 10 μm or more. It is preferable that the interval between the comb-shaped blades is set to be equal to the size of the pixel, and the width of the blade is 1 μm or more. Here, the layer to be removed may be only the second electrode material on the partition.

Further, it is not necessary to remove all of the second electrode material on the partition walls, but it is sufficient to make the second electrode material smaller than the width of the partition walls so as to form a groove. This comb-shaped cutting tool can be made by various methods.For example, a method of fixing a small cutting blade to a flat plate with holes or depressions in accordance with the pixel pitch, or a stainless steel having a desired thickness is used. By etching the plate, a comb-like blade having a desired pitch and width can be obtained.

Since the adhesive force between the organic material and the electrode material and between the organic material and the partition walls are both small, they can be easily scraped off. Therefore, it is desirable that the cutting edge is sharp, but the cutting edge is rounded. Good if not. As can be seen from FIG. 2, since the height of the layer to be removed differs between the portion with and without the ITO film by the thickness of the ITO, the comb-like blade needs elasticity so as to follow the unevenness of the partition wall. . By scanning the comb-like blade on the partition wall so as to scrape off the organic layer and the second electrode layer, a strip-shaped second electrode can be obtained. FIG. 3 shows a state in which the second electrode material on the partition is removed by IT.
It is shown in a sectional view in the direction along the O electrode. However, as described above, shavings are scattered on the organic EL element as it is as described above, which has an adverse effect such as causing a short circuit or causing damage and disconnection.

Therefore, it is preferable to use a method in which an inert gas such as nitrogen or argon is blown to blow off shavings, and the blown shavings are sucked off by vacuum suction. An example is shown in FIG. An inert gas is blown from the front of the cutting blade to blow off shavings generated when the second electrode material is shaved, and the vacuum is sucked and sucked at the rear to prevent shavings on the organic EL element from being left. I can do it. There is no shavings left on the organic EL element by either of the inert gas blowing and vacuum suction methods, but it is preferable to use them together. In the production of the organic thin film EL device of the present invention, it is also possible to reverse the production order, produce the cathode, the light emitting layer, and the anode in this order, and scrape off the anode on the partition walls.

In the manufacturing method of the present invention, the cutting is performed by:
Although it has been described that only the second electrode material on the partition is peeled off, when cutting the second electrode material on the partition, even if the organic material on the partition is peeled off, it does not affect each pixel portion. There is no problem in manufacturing the organic EL device of the present invention. Organic E prepared by the method of the present invention
Oxygen in the air for the anode, organic layer, and cathode of the L element,
In order to prevent deterioration due to moisture, dust, etc., it is desirable to seal the entire anode, organic layer, and cathode portion.

In the organic EL device obtained by the manufacturing method of the present invention, the first electrode and the second electrode are formed in a band shape via the organic layer. Thus, a matrix is formed by the first electrode and the second electrode, and the first electrode driving circuit and the second electrode driving circuit sequentially drive the pixels formed by this matrix, so that the light emitting layer of the pixel portion is formed. Light emission is sequentially controlled based on the image signal.

[0023]

According to the manufacturing method of the present invention, the strip-shaped second electrode having a narrow electrode gap is precisely machined, and a short circuit between the electrodes can be avoided.
The display quality of the L element is high.

[0024]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the examples.

Example 1 A glass substrate patterned so that ITO (first electrode) was 100 μm in width and the gap was 30 μm in a belt shape was sufficiently washed, and a Hoechst resist AZ TFP-N was spin-coated. Next, prebaking was performed on a hot plate. Width 3 on pre-baked resist
Exposure was performed with a photomask processed so as to form a resist partition in a 0 μm band shape. The exposed substrate is placed in a developing solution, the resist is developed, the substrate is placed on a hot plate, post-baked, and a desired band-shaped IT
A substrate on which a strip-shaped partition having a height of 3 μm crossing O was formed.

This substrate was fixed on a substrate holder of a commercially available vapor deposition apparatus, and N, N′-diphenyl-N, N′-bis- (3-methylphenyl) -4,4′-diamine was added to 8 × 10 ^−4. At a degree of vacuum of Pa, the deposition rate is 0.1-0.
A hole injection / transport layer having a thickness of 50 nm was formed by vapor deposition from a quartz crucible on a substrate at a rate of 2 nm / sec. Next, 8
Tris (8-human peroxyquinolino) aluminum was deposited from a quartz crucible at a vacuum of × 10 ^-4 Pa at a rate of 0.3 to 0.4 nm / sec. Was formed. Then, as a cathode electrode, magnesium was vapor-deposited from a graphite crucible at a degree of vacuum of 1 × 10 ⁻³ Pa at a rate of 1 to 1.2 nm / sec and silver was vapor-deposited from a graphite crucible at a rate of 0.08 to 0.11 nm / sec. 150n in seconds
It was prepared by co-evaporating a magnesium-silver electrode (second electrode) with a thickness of m. A comb-shaped flat plate having cutting needles each having a tip of 5 μm was attached at an interval of 130 μm, and the needle was pressed against the center of the partition wall to scan over the element. Traces of 5 μm width of the second electrode material are formed on the partition walls, and when a DC voltage is applied to each pixel using ITO as an anode, only the pixel to which the DC voltage is applied emits light, and each pixel is not short-circuited. That was confirmed.

Example 2 A comb-shaped blade having a width of 50 μm and a center interval of 130 μm was prepared by a 100 μm-thick stainless steel plate photolithography method, and scanning was performed on the partition walls in the same manner as in Example 1. The organic layer and the second electrode layer on the partition were scraped off. When a DC voltage was applied to each pixel of the device using ITO as an anode, only the pixel to which the DC voltage was applied emitted light, and it was confirmed that each pixel was not short-circuited.

Example 3 An inert spraying jig and a vacuum suction jig of a comb-shaped blade produced in the same manner as in Example 2 were attached, and the partition walls were scanned as in Example 1. The organic layer and the second electrode layer on the partition were scraped off to form a strip-shaped second electrode. When a DC voltage was applied to each pixel of the device using ITO as an anode, only the pixel to which the DC voltage was applied emitted light, and it was confirmed that each pixel was not short-circuited.

Comparative Example 1 An element was produced in the same manner as in Example 1 except that no partition was provided. The comb-shaped blade shown in Example 1 was scanned so as to be orthogonal to the strip-shaped ITO electrode. The resistance value between each pixel before performing this scanning was 20Ω, but the resistance value after cutting was 2Ω.
00KΩ, and did not have sufficient insulation. This indicates that the second electrode material was not completely removed.

[0030]

As described above, the organic EL device obtained by the manufacturing method of the present invention is extremely useful as a light emitting device for a display, and the manufacturing method has high industrial value.

[Brief description of the drawings]

FIG. 1 is an example of a configuration of an organic EL element in which metal deposition is performed on the entire surface, and is a cross-sectional view along a direction along an ITO electrode.

FIG. 2 is a cross-sectional view of an example of a configuration of an organic EL element in which metal deposition is performed on the entire surface, in a direction orthogonal to an ITO electrode.

FIG. 3 is a cross-sectional view along a direction along an ITO electrode of an organic EL element obtained by subjecting a metal electrode to fine processing by the manufacturing method of the present invention.

FIG. 4 is a schematic diagram of a cross section of an upper part of a partition wall in a direction orthogonal to an ITO electrode when a fine processing is performed on a metal electrode by a manufacturing method of the present invention.

[Explanation of symbols]

 1. 1. Glass substrate (substrate) 2. ITO electrode (first electrode) Partition wall 4. 4. Organic compound layer (organic layer) 5. Metal electrode (second electrode) Comb blade 7. 7. Inert gas blowing Vacuum inlet 9. Inert gas

Claims (4)

[Claims] 1. An electrode pair of a first electrode and a second electrode arranged in a plurality of strips facing each other and an organic layer interposed between the electrode pairs, and a plurality of portions sandwiched between the electrode pairs emit light. In the method of manufacturing an electroluminescent element as a region, a single layer or a plurality of layers are formed on a substrate on which a plurality of strip-shaped first electrodes and a plurality of strip-shaped partition walls made of an insulator are arranged so as to be orthogonal to the electrodes. Forming a second electrode layer on the entire surface of the device and then shaving off the organic material and the second electrode material respectively present on the upper part of the partition walls to form a band-shaped second electrode. A method for producing an organic electroluminescent device. 2. After forming a second electrode layer on the entire surface of the device,
2. The organic electroluminescent device according to claim 1, further comprising a step of shaving off the organic material and the second electrode material respectively present on the upper portion of the partition wall using a cutting blade or a needle made of metal or plastic. Production method. 3. The method according to claim 2, further comprising a step of vacuum-suctioning cutting chips generated when the organic material and the second electrode material are scraped off to peel off the organic material and the second electrode material on the partition walls. Of manufacturing an organic electroluminescent device. 4. The organic material and the second electrode material on the partition wall according to claim 2, wherein chips generated when shaving the organic material and the second electrode material are blown off with a gas, and the chips are vacuumed to separate the organic material and the second electrode material on the partition walls. A method for manufacturing an organic electroluminescent device, comprising the steps of: