JP2003187971A - Manufacturing method of organic electroluminescence element, and manufacturing method of light-emitting device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an organic EL element in which impurities such as a resist are not remained on the electrode and occurrence of a dark spot due to impurities or the like and defects or the like of the electrode are suppressed by a simple method. <P>SOLUTION: This is a manufacturing method of an organic EL element having at least a structure in which a first electrode, one or more of organic compound layers, and a second electrode are laminated on a substrate. An electrode layer (302a) made of the above first electrode material is formed on the substrate (301), and an organic protection layer (303a) made of a material of a layer adjoining the above first electrode out of the organic compound layers is formed on the electrode layer (302a), and then the above first electrode (302c) is made by carrying out pattern forming on the above electrode layer. Thereby, even if some remainder (303b) of the organic protection layer is left on the substrate, it does not become an impurity. <P>COPYRIGHT: (C)2003,JPO

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 electroluminescence (organic EL) element, and an organic EL exposure light source or an organic EL display device using the same.
Regarding the manufacturing method of the L light emitting device, more specifically, organic EL
The present invention relates to a pattern forming method of an electrode of a device.

[0002]

2. Description of the Related Art Conventionally, a first electrode formed on a substrate, an organic compound layer formed on the first electrode, and a second electrode formed on the organic compound layer are laminated. Organic EL devices having a structure are well known. Then, an organic E in which a plurality of such organic EL elements are used as a light emitting source
Development is actively being carried out for using the L light emitting device as an exposure light source included in an electrophotographic printer or the like, or as a display device applicable to a display unit such as a mobile terminal.

FIG. 1 is a schematic diagram showing an example of an organic EL light emitting device in which organic EL elements are arranged in a matrix. FIG. 6A is a plan view showing an array of pixels.
(B) is a sectional view of AA '. In FIG. 1, 10
1 is a substrate, 102 is a first electrode, 103 is an organic compound layer,
104 is a second electrode. Further, 105 is the first electrode and the second
It is a pixel defined by a region in which an organic compound layer is interposed between the pixel and the electrode.

FIG. 1 shows an example in which dot-shaped organic EL elements are formed as pixels on a surface of a substrate and are arranged in a matrix, and each organic EL element can emit light separately. There is. In this light emitting device, by appropriately selecting the organic EL element to emit light,
Various images can be displayed.

In such a display device manufacturing method, a mask is used in vacuum deposition in a low molecular weight organic EL material, as disclosed in JP-A-5-258859 and JP-A-5-275172. A general method of patterning is described below.

FIG. 2 is a perspective view schematically showing a state in which the second electrode of the organic EL element is formed by the conventional method. 2, the same reference numerals as those in FIG. 1 denote the same members, 201 is a mask, and 202 is a through hole.

First, a first electrode 102 made of ITO or the like is formed on a transparent substrate 101. Next, the hole injection layer,
An organic compound layer 103 such as a light emitting layer is formed on the entire surface. Finally, as shown in FIG. 2, a mask 201 having stripe-shaped through holes 202 is prepared, and the mask 201 is provided above the light emitting layer so that the through holes are orthogonal to the first electrode 102 when viewed on the projection surface of the transparent substrate 101. Then, the mask is fixed to the second electrode 104, and the second electrode 104 is formed in a stripe shape by an evaporation method. In this way, it is possible to obtain a display device in which the organic EL element has the first electrode and the second electrode formed in the overlapping portion when viewed on the projection surface with respect to the transparent substrate. In this display device, a pixel (organic EL element) at an arbitrary portion can be made to emit light by selecting the first electrode line and the second electrode line through which a current flows.

Since the display device using the organic EL element emits light by itself, it has an advantage that it can have a wide viewing angle, a display with a thickness of several millimeters or less, and can operate in a wide temperature range.

[0009]

When a point where no light is emitted, that is, a dark spot occurs once inside the organic EL element, the dark spot may grow and the display quality may deteriorate. There are various causes for this dark spot, and one of them is a particle existing on the first electrode.

Particles that may be present on the first electrode include dust in the manufacturing environment, resist residue when forming the pattern of the first electrode, and the like. The first electrode is formed into a film on the entire surface of the substrate by sputtering or the like, is coated with a resist, and is formed into an arbitrary shape by exposure, development and etching. Then, after forming the first electrode having an arbitrary shape, the resist is removed. However, this resist and dust in the manufacturing environment may remain on the first electrode, and if an organic EL element is created in the state where the resist and dust in the manufacturing environment remain, the Occasionally, dark spots were generated and grew with dust as the core.

As a conventional technique, Japanese Patent Laid-Open No. 9-232075
As disclosed in Japanese Unexamined Patent Publication No. 10-92585, the substrate is washed with a directional ultraviolet ray or an ion beam, or as disclosed in Japanese Unexamined Patent Publication No. 10-92585.
Improving the cleaning method such that the electrode is exposed to a plasma gas selected from oxygen, nitrogen, argon, helium, neon, xenon, krypton and a mixture thereof in the plasma reactor, or a method using plasma ashing in combination Has been taken. However, under the present circumstances, removal of the resist is insufficient with improved cleaning, and control is difficult when plasma ashing is used, and further, the electrodes may be damaged. In particular, if the resist adheres to the electrode and is dried, it is difficult to remove it.

The present invention has been made in order to solve the above-mentioned problems, and does not leave impurities such as resist on the electrodes by a simple method, and dark spots due to impurities on the electrodes or defects of the electrodes. It is an object of the present invention to provide a method for manufacturing an organic EL element capable of suppressing the occurrence of

The present invention also provides a method of manufacturing an organic EL light emitting device such as an organic EL exposure light source or an organic EL display device having at least a structure in which a plurality of organic EL elements are arranged, which utilizes the above method of manufacturing an organic EL element. It is intended to be provided.

[0014]

A first invention for solving the above-mentioned problems has a structure in which a first electrode, one or more organic compound layers and a second electrode are laminated on a substrate. A method for manufacturing an organic electroluminescent element having at least an electrode layer made of a material of the first electrode on the substrate, and forming the electrode layer on the electrode layer on the first electrode of the organic compound layer. The method is characterized by including a step of forming a pattern on the electrode layer to form the first electrode after forming an organic protective layer made of a material of a layer in contact with the electrode layer.

According to the present invention, in the first aspect, "the electrode layer is formed on the entire surface of the substrate", "the organic protective layer is formed on the entire surface of the electrode layer". ”,“ The film forming method of the electrode layer and the organic protective layer,
A method of forming a film of the electrode layer by a physical vapor deposition method in a vacuum and subsequently forming a film of the organic protective layer in the vacuum "," after forming the pattern of the first electrode, the organic protective layer At least a part of the above "and" using a dry etching method as a method for removing at least a part of the organic protective layer "are included as preferable embodiments.

The present invention also provides, as a second invention, an organic electroluminescence element having at least a structure in which a first electrode, one or more organic compound layers, and a second electrode are laminated on a substrate. A method for manufacturing an organic electroluminescence light-emitting device having at least a plurality of arranged structures, the method including manufacturing the organic electroluminescence element by the manufacturing method of the first invention.

The present invention further includes a method of manufacturing an organic electroluminescence exposure light source, which is characterized by using the method of manufacturing the organic electroluminescence light emitting device of the second invention.

Further, the present invention also includes a method of manufacturing an organic electroluminescence display device characterized by using the method of manufacturing an organic electroluminescence light emitting device of the second invention.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is a method for manufacturing an organic electroluminescence device having at least a structure in which a first electrode, one or more organic compound layers, and a second electrode are laminated on a substrate. The first on the substrate
After forming an electrode layer made of an electrode material and forming an organic protective layer made of a material of a layer of the organic compound layer in contact with the first electrode on the electrode layer, a pattern is formed on the electrode layer. It is characterized by including a step of forming the first electrode.

By forming such an organic protective layer, it is possible to remarkably reduce the adhesion of impurities to the surface of the electrode layer when forming the pattern of the first electrode, and to reduce the amount of impurities in the electrode layer after forming the pattern. It is also possible to protect the non-removed portion which is one electrode so as not to be damaged by the pattern formation. Furthermore, when the organic compound layer is formed after cleaning the substrate on which the first electrode is formed after forming the pattern of the first electrode, a part or most of the residue of the organic protective layer is removed. Even if there exists, it does not become an impurity because it is made of the material of the layer of the organic compound layer that is in contact with the first electrode. Thus, according to the present invention,
By a simple method, when a pattern of the first electrode is formed, impurities such as a resist remain on the first electrode, or the first electrode is damaged to cause a void portion. It is possible to prevent the generation of nuclei and manufacture a high-quality and highly durable organic EL element.

The substrate of the present invention needs to be transparent or semi-transparent when the light extraction side is the first electrode side,
In this case, the first electrode also needs to be a transparent electrode.

The preferred embodiments of the present invention will be described in detail below, but the present invention is not limited to these embodiments.

In this embodiment, an electrode layer is formed on the entire surface of one side of the substrate, an organic protective layer is formed on the entire surface of the electrode layer, and then the electrode layer is patterned into an arbitrary shape to form a first electrode. Then, a series of steps of removing the organic protective layer on the first electrode is included.

As described above, if the electrode layer is formed on the entire surface of the substrate, a mask or the like is unnecessary, and it is preferable that the organic protective layer is also formed on the entire surface of the electrode layer for the same reason.

The present embodiment will be described below with reference to FIG. In FIG. 3, 301 is a substrate, 302a is an electrode layer, 3
02c is a first electrode, 303a is an organic protective layer made of the material of the hole transport layer, 303b is a residue of the organic protective layer, 303c
Is a hole transport layer, 304 is a resist, 305 is a mask, 3
Reference numeral 06 is a light emitting layer which also serves as an electron transport layer, and 307 is a second electrode.

First, a transparent electrode layer 302a such as tin oxide indium (ITO) or tin oxide thin film is formed on the entire surface of a transparent substrate 301 such as glass (FIG. 3A). In addition,
The electrode layer 302a may be semitransparent. Electrode layer 302
As a method of forming a, any of a sputtering method, an electron beam method, a chemical reaction method and the like may be used.

Next, an organic protective layer 303a is formed on the entire surface of the electrode layer 302a (FIG. 3B). As a method for forming the organic protective layer, any of a vacuum vapor deposition method, a spin coating method, a screen printing method and the like may be used. It is preferable to use the vacuum vapor deposition method because the possibility of dust attachment is further reduced when the layers are formed in the same vacuum container.

Next, in order to pattern the electrode layer into an arbitrary shape, a resist 304 is applied on the entire surface of the organic protective layer (FIG. 3C). As a resist coating method, there are a spin coating method, a screen printing method and the like, but any method may be used. The resist has a negative type in which a photosensitive portion becomes insoluble in a developing solution and a positive type in which a photosensitive portion becomes soluble in a developing solution at the time of exposure, but either may be used.

Next, the resist is heated and dried if necessary, and then exposed to a desired shape, developed (FIG. 3D), and wet-etched to form the first electrode (transparent conductive film) 3 having a desired shape.
02c is formed (FIG. 3E). At this time, the thickness of the organic protective layer on the electrode layer is several tens to several hundred Å and the density of the layer is low, so the etching solution enters the organic protective layer and partially etches the electrode layer to be left. However, in the organic EL element, when the taper angle of the end portion of the first electrode is smaller, the film thickness becomes more uniform when the organic compound layers are stacked, the concentration of charges is reduced, and It is possible to prevent the occurrence of dark spots.

Next, the resist and the organic protective layer are removed (FIG. 3 (f)). Using a resist stripper as a removal method,
Although there is ashing or the like, any removing method may be used. In the unlikely event that the first electrode 302
Even if the residue 303b of the organic protective layer remains on c, it does not cause a problem due to the reasons described above.

Next, a hole injection layer 303c is formed on the first electrode 302c (FIG. 3 (g)). Hole injection layer 303
As a method for forming c, any of a vapor deposition method, a dipping method, a spin coating method and the like may be used. The thickness of the hole injection layer is preferably as thin as possible in consideration of carrier mobility and taking out light from the glass substrate side. However, if it is too thin, dielectric breakdown occurs in pinholes and the like. On the other hand, if the thickness of the hole injection layer is too large, the driving voltage required for the completed organic EL element will be high.

Next, a light emitting layer 306 which also serves as an electron transport layer is formed (FIG. 3 (h)). As a method for forming the light emitting layer 306, any of a vapor deposition method, a spin coating method and the like may be used.

Next, a mask (not shown) is fixed on the film forming surface to form the second electrode pattern, and the second electrode 307 is formed (FIG. 3 (i)).

Through the above steps, the growth of the non-light emitting portion (dark spot) due to the defect of the first electrode can be suppressed.
An L element is obtained.

When the organic protective layer is formed on the electrode layer by the spin coating method as in the present embodiment, the thinner the organic protective layer is, the easier the etching solution penetrates during the formation of the first electrode. It is preferable that the solid content of the droplet is low.

Next, various devices using the organic EL element according to the present invention will be briefly described. FIG. 4 is a circuit diagram showing an example of an organic EL display device to which the manufacturing method of the present invention can be applied, and FIG. 5 is a circuit diagram showing an example of an organic EL exposure light source to which the manufacturing method of the present invention can be applied. Specifically, FIG. 4 is a display display in which organic EL elements are two-dimensionally arranged, and FIG. 5 is a printer head light source in which one-dimensionally is arranged.

These two examples differ only in the way in which the organic EL elements are arranged, and the driving system is basically the same. In both cases, the organic EL element D11 (capacitance part is omitted) is provided between the anode wiring Lx1 and the cathode wiring Ly1, D21 is provided between Lx1 and Ly2, and Lx2 and Ly are provided.
D12 is connected to 1, and D22 is connected to Lx2 and Ly2. In these devices, each organic EL element can be made to emit light individually by applying an appropriate potential to any anode wiring and cathode wiring, and various light emission patterns and images can be displayed.

Even when these devices are manufactured,
The method for manufacturing an organic EL element of the present invention as described above can be expanded and applied as it is, the same effects as described above can be obtained, and a device of high quality and high durability can be realized.

As described above, the present invention is not limited to the manufacture of monochromatic light-emitting elements, but also an exposure light source or a full-color display device (passive matrix type or active matrix type) having a structure in which organic EL elements are arranged in an array or a matrix. The present invention can also be applied to the manufacture of a light emitting device such as a display device).

[0040]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 A method for manufacturing an organic EL element in this example will be described with reference to FIG. In this example, reference numerals in FIG. 3 are 301: glass substrate, 302a: electrode layer, 302c: ITO transparent electrode, 303a: organic protective layer, 303b: residue, 303c: hole injection layer, 304.
Is a photosensitive resin layer, 305 is a mask, 306 is a light emitting layer which also serves as an electron transport layer, and 307 is an Al electrode.

First, an electrode layer 302a made of the material of the ITO transparent electrode (first electrode) was formed on the entire surface of the glass substrate 301 by the sputtering method (FIG. 3 (a)).

Next, a hole injection material (triphenylamine 6
Polymer (TPA-6: molecular weight 1461, melting point 277 ° C., T
An organic protective layer 303a composed of (g156 ° C.)) is formed on the entire surface of the electrode layer 302a by a physical vapor deposition method (FIG. 3).
(B)).

Next, a photosensitive resin (mixture of novolac resin and pegmia) was formed on the entire surface of the organic protective layer 303a (FIG. 3 (c)).

Next, the electrode layer 302a and the organic protective layer 303a are patterned by exposure using a mask 305, development (FIG. 3D), and etching to form the ITO transparent electrode (first electrode) 302c into a desired shape. (Fig. 3 (e)).

Next, the entire substrate was immersed in a resist stripping solution to remove the photosensitive resin layer 304 and the organic protective layer 303a (FIG. 3 (f)). At this time, a part of the residue 303b of the organic protective layer may remain on the ITO transparent electrode (first electrode) 302c, but this is not a problem because of the reasons described above.

Next, the above-mentioned substrate was immersed in isopropyl alcohol, ultrasonically cleaned, and dried in an environment of 120 ° C. Next, as a hole injecting material, triphenylamine hexamer (TPA-6: molecular weight 1461, melting point 277).
C., Tg 156.degree. C.) by spin coating, and dried by heating to form a hole injection layer 303c (FIG. 3 (g)).

Next, a light emitting layer 306 which is also composed of an 8-hydroxyquinoline metal complex represented by tris (8-quinolinol) aluminum (aluminumquinoline complex) as a light emitting material and an electron transporting material and which also serves as an electron transporting layer is formed by a physical vapor deposition method. A film was formed (FIG. 3 (h)).

Next, using a mask having a through hole corresponding to the second electrode pattern, Al-Li as an electron injection layer (not shown) is formed by a physical vapor deposition method, and then an Al electrode (second electrode) is formed. ) 307 was formed by a physical vapor deposition method (FIG. 3 (i)).

Finally, an organic EL device was manufactured through a sealing process.

Example 2 A method of manufacturing an organic EL element in this example will be described with reference to FIGS.
6 and 7 are process diagrams showing a second embodiment of the method for manufacturing an organic EL device of the present invention. In these figures, 70
1 is a glass substrate, 702a is an electrode layer, and 702c is ITO.
Transparent electrode, 703a is an organic protective layer, 703b is a residue, 7
Reference numeral 03c is a hole transport layer, 704 is a photosensitive resin layer, 705 is a hole injection layer, 706 is a mask, 707 is a light emitting layer also serving as an electron transport layer, and 708 is an Al electrode.

First, an electrode layer 702a made of the material of the ITO transparent electrode (first electrode) was formed on the entire surface of the glass substrate 701 by the sputtering method (FIG. 6 (a)).

Next, an organic protective layer 703a made of an organic material (copper phthalocyanine) is formed on the electrode layer 702 by physical vapor deposition.
A film was formed on the entire surface of a (FIG. 6B).

Next, a photosensitive resin (a mixture of novolak resin and pegmia) was formed on the entire surface of the organic protective layer 703a (FIG. 6C).

Next, the electrode layer 702a and the organic protective layer 703a are patterned by exposure using a mask 706, development (FIG. 6D), and etching to form the ITO transparent electrode (first electrode) 702c into a desired shape. (Fig. 6 (e)).

Next, the entire substrate was treated with plasma ashing and UV ozone to remove the organic layer and the photosensitive resin layer (FIG. 6 (f)). At this time, ITO transparent electrode (first electrode)
A part of the residue 703b of the organic protective layer may remain on the layer 702c, but this is not a problem because of the reason described above.

Next, copper phthalocyanine was deposited by physical vapor deposition to form a hole transport layer 703c (FIG. 6).
(G)).

Next, as a hole injecting material, triphenylamine hexamer (TPA-6: molecular weight 1461, melting point 277).
C., Tg 156.degree. C.) by a physical vapor deposition method to form a hole injection layer 705 (FIG. 7 (h)).

Next, an 8-hydroxyquinoline metal complex represented by tris (8-quinolinol) aluminum (aluminumquinoline complex) is formed as a light emitting material and an electron transporting material by a physical vapor deposition method to emit light which also serves as an electron transporting layer. A layer 707 was formed (FIG. 7 (i)).

Next, using a mask having a through hole corresponding to the second electrode pattern, Al-Li as an electron injection layer (not shown) is formed by a physical vapor deposition method, and then an Al electrode (second electrode) is formed. ) 708 was deposited by physical vapor deposition (FIG. 7 (j)).

Finally, an organic EL device was manufactured through a sealing process.

[0062]

As described above, according to the present invention,
By a simple method, when a pattern of the first electrode is formed, impurities such as a resist remain on the first electrode, or the first electrode is damaged to cause a void portion. It is possible to prevent the generation of nuclei and manufacture a high-quality and highly durable organic EL element.

Also, in a light emitting device such as an exposure light source or a display device having a structure in which a plurality of organic EL elements are arranged in an array or a matrix, by performing the manufacturing method of the present invention, the core of a dark spot is formed. It is possible to realize a high-quality and high-durability device with less waste.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of an organic EL light emitting device in which organic EL elements are arranged in a matrix.
FIG. 6A is a plan view showing an array of pixels. (B) is A
It is a sectional view of -A '.

FIG. 2 is a perspective view schematically showing how a second electrode of an organic EL element is formed by a conventional method.

FIG. 3 is a process drawing showing the first embodiment of the method for manufacturing an organic EL device of the present invention.

FIG. 4 is a circuit diagram showing an example of an organic EL display device to which the manufacturing method of the present invention can be applied.

FIG. 5 is a circuit diagram showing an example of an organic EL exposure light source to which the manufacturing method of the present invention can be applied.

FIG. 6 is a process drawing showing a second embodiment of the method for manufacturing an organic EL device of the present invention.

FIG. 7 is a process drawing showing a second embodiment of the method for manufacturing an organic EL element of the present invention.

[Explanation of symbols]

101 substrate 102 first electrode 103 Organic compound layer 104 second electrode 105 pixels 201 mask 202 through hole 301 substrate 302a electrode layer 302c First electrode 303a Organic protective layer 303b residue 303c Hole transport layer 304 Photosensitive resin layer 305 mask 306 Light-emitting layer that also functions as an electron-transporting layer 307 Second electrode 701 glass substrate 702a electrode layer 702c ITO transparent electrode 703a Organic protective layer 703b residue 703c Hole transport layer 704 Photosensitive resin layer 705 hole injection layer 706 mask 707 Light-emitting layer also serving as electron-transporting layer 708 Al electrode

Claims (9)

[Claims] 1. A method for manufacturing an organic electroluminescence device having at least a structure in which a first electrode, one or a plurality of organic compound layers, and a second electrode are laminated on a substrate, the method comprising: An electrode layer made of the material of the first electrode is formed, and the first of the organic compound layers is formed on the electrode layer.
A method of manufacturing an organic electroluminescence device, comprising: forming an organic protective layer made of a material of a layer in contact with an electrode, and then patterning the electrode layer to produce the first electrode. 2. The method for manufacturing an organic electroluminescence device according to claim 1, wherein the electrode layer is formed on the entire surface of the substrate. 3. The method for manufacturing an organic electroluminescence device according to claim 1, wherein the organic protective layer is formed on the entire surface of the electrode layer. 4. The method of forming the electrode layer and the organic protective layer is a method of forming the electrode layer by a physical vapor deposition method in vacuum and then continuously forming the organic protective layer in the vacuum. 4. The method for manufacturing an organic electroluminescent element according to claim 1, wherein 5. The organic electroluminescence device according to claim 1, wherein at least a part of the organic protective layer is removed after the patterning of the first electrode. Production method. 6. The method for manufacturing an organic electroluminescence device according to claim 5, wherein a dry etching method is used as a method for removing at least a part of the organic protective layer. 7. An organic electroluminescent device having at least a structure in which a plurality of organic electroluminescent elements having a structure in which a first electrode, one or a plurality of organic compound layers, and a second electrode are laminated on a substrate. It is a manufacturing method of a luminescent light emitting device, Comprising: The said organic electroluminescent element is manufactured by the manufacturing method in any one of Claim 1 thru | or 6, The manufacturing method of the organic electroluminescent light emitting device characterized by the above-mentioned. 8. A method of manufacturing an organic electroluminescence exposure light source, which uses the method of manufacturing an organic electroluminescence light emitting device according to claim 7. 9. A method of manufacturing an organic electroluminescence display device, which uses the method of manufacturing an organic electroluminescence light emitting device according to claim 7.