JP3849726B2 - Method for manufacturing organic electroluminescent device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for manufacturing an organic EL (Electroluminescence) element used as a light emitting element or a display element, and more particularly to a method for manufacturing an organic EL element that performs fine processing using a laser ablation method. is there.
[0002]
[Prior art]
In recent years, a next-generation flat panel display replacing CRT (Cathode Ray Tube) has attracted much attention. An organic EL element has attracted attention as a display element for a flat panel display, and research is being conducted.
The organic EL element includes a pair of electrodes and at least one organic layer containing a light-emitting substance sandwiched therebetween. It is considered that holes and electrons injected from each electrode during energization move in the organic layer and recombine to generate singlet excitons, and light is emitted from the excitons.
[0003]
In addition, as a structure of such an organic EL element, for example, a two-layer structure such as an anode / hole transport layer / light-emitting layer / cathode, or an anode / light-emitting layer / electron transport layer / cathode, or an anode / hole transport layer / light-emitting layer / There is a three-layer structure of electron transport layer / cathode.
[0004]
In addition, in the method for producing an organic EL element having such a laminated structure, for example, a vacuum deposition method or an ion beam sputtering method is used to form an electrode, and an organic layer such as a hole transport layer, a light emitting layer, or an electron transport layer is used. For example, a vacuum vapor deposition method, a spin coating method, an LB method, or the like is used.
[0005]
[Problems to be solved by the invention]
By the way, when producing a flat panel display in which a large number of organic EL elements are arranged, it is required to accurately form each organic EL element.
However, when an organic EL element is formed by using the above-described conventional vacuum deposition method or the like, pattern deviation occurs due to a slight gap between the patterned mask and the substrate, so that it is very difficult to manufacture each organic EL element with high accuracy. It was difficult. Further, even when trying to miniaturize each organic EL element, it is difficult to miniaturize the organic EL element because there is a limit to the miniaturization of the pattern of the mask to be patterned.
[0006]
Therefore, the present invention has been made in view of the above-described problems, and an object thereof is to provide a method for manufacturing an organic EL element capable of forming an organic EL element having a fine element pattern with high accuracy. .
[0007]
[Means for Solving the Problems]
As a result of intensive studies in order to solve the above problems, the inventors of the present invention used a laser ablation method to irradiate a minute region in which each organic EL element is to be separated with a high-power laser, and the minute separation region. It has been conceived that by evaporating the substance provided on the organic EL element, each organic EL element can be separated and an organic EL element having a fine element pattern can be formed with high accuracy. Therefore, the said subject is achieved by the manufacturing method of the organic EL element which concerns on the following this invention.
[0008]
That is, the organic EL device manufacturing method according to claim 1 includes a first step of forming a resist patterned in a predetermined shape on a transparent electrode, and an organic layer including a light emitting layer on the transparent electrode and the resist. A second step of forming a layer, a third step of forming a metal electrode layer on the organic layer including the light-emitting layer, and irradiating the resist through the transparent electrode from the transparent electrode side And evaporating the resist, selectively removing only the organic layer and the metal electrode layer including the light emitting layer on the resist, and the organic layer including the light emitting layer stacked on the transparent electrode and And a fourth step of separating the metal electrode layer.
[0009]
As described above, in the method for producing an organic EL device according to the present invention, a resist patterned in a predetermined shape is formed on a transparent electrode, and an organic layer and a metal electrode layer including a light emitting layer are sequentially formed on the transparent electrode and the resist. After laminating, the resist is irradiated with light through the transparent electrode from the transparent electrode side to evaporate the resist, and at the same time, only the organic layer and the metal electrode layer including the light emitting layer on the resist are selectively removed. By separating the organic layer including the light emitting layer and the metal electrode layer, each organic EL element can be separated. In other words, the accuracy with which each organic EL element is separated depends on the patterning accuracy of the resist, and the patterning of this resist layer can be performed with high precision using a photolithography method. It becomes possible to miniaturize with high precision.
[0010]
In the method of manufacturing an organic electroluminescent element according to claim 1, the organic layer including the light emitting layer is preferably a hole transport layer and a light emitting layer which are sequentially stacked. Therefore, the method for producing an organic EL device according to the present invention can be applied to an organic EL device having a two-layer structure of anode / hole transport layer / light emitting layer / cathode.
A method for producing an organic EL device according to claim 3 is the method for producing an organic electroluminescent device according to claim 1, wherein the organic layer including the light emitting layer is a light emitting layer and an electron transport layer that are sequentially laminated. It is characterized by that. Therefore, the method for producing an organic EL device according to the present invention can be applied to an organic EL device having a two-layer structure of anode / light emitting layer / electron transport layer / cathode.
[0011]
In the method for manufacturing an organic electroluminescent element according to claim 1, the organic layer including the light emitting layer is preferably a hole transport layer, a light emitting layer, and an electron transport layer which are sequentially stacked. Therefore, the method for producing an organic EL device according to the present invention can be applied to an organic EL device having a three-layer structure of anode / hole transport layer / light emitting layer / electron transport layer / cathode.
[0012]
In the method for manufacturing an organic electroluminescent element, the resist formed on the transparent electrode in the first step contains a dye that absorbs light of a predetermined wavelength, and in the fourth step The light applied to the resist preferably has the predetermined wavelength.
Thus, in the method for producing an organic EL element according to the present invention, by using a resist containing a dye that absorbs light of a predetermined wavelength, and irradiating the resist with light having a predetermined wavelength, When light having this predetermined wavelength is irradiated, the dye contained in the resist absorbs the light and cleaves the bonds between the resist molecules, so that the resist can be easily decomposed and evaporated. Is possible. The resist is preferably one that does not decompose or evaporate during oxygen plasma treatment that is generally used for the purpose of cleaning the surface of the transparent electrode in the production of an organic EL element.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
1 to 5 are process cross-sectional views illustrating a method for manufacturing an organic EL element according to an embodiment of the present invention.
First, as shown in FIG. 1, an ITO (Indium Tin Oxide) film is deposited on a transparent glass substrate 10 by using, for example, a vacuum deposition method to form an ITO anode 12. Subsequently, a photoresist layer 14 is formed on the ITO anode 12 by using, for example, a coating method. As a material of the photoresist layer 14, for example, a heat-resistant polyimide resist mixed with a rhodamine dye or a coumarin dye known as a laser dye is used.
[0014]
Thereafter, exposure and development by UV (ultra-violet rays) irradiation are performed using a photolithography method, and the photoresist layer 14 is patterned into a desired pattern. At this time, since the photoresist layer 14 is patterned using a photolithography method, it is possible to form the photoresist layer 14 with a fine pattern with high accuracy.
[0015]
Next, as shown in FIG. 2, for example, TPD (N, N′-diphenyl) as a material for a hole transport layer is formed on the ITO anode 12 and the photoresist layer 14 patterned in a desired pattern by using, for example, a vacuum deposition method. -N, N'-di (3-methylphenyl) 4,4'-diaminobiphenyl), for example Alq3 (tris (8-quinolinol) aluminum) as the material of the light-emitting layer, for example Αl ( (Aluminum) are sequentially laminated to form a hole transport layer 16 made of TPD, a light emitting layer 18 made of Alq3, and a cathode 20. Thus, the ITO anode 12, the hole transport layer 16, the light emitting layer 18, and the Al cathode 20 are sequentially laminated on the transparent glass substrate 10 to form a common structure for each organic EL element.
[0016]
Next, as shown in FIG. 3, a high-power laser such as a Kr (krypton) ion laser or Ar (argon) ion laser is used as a light source, and the photoresist layer 14 is irradiated with laser light from the back side of the transparent glass substrate 10. .
[0017]
At this time, the transparent glass substrate 10 and the ITO anode 12 transmit laser light having a wavelength in the visible region output from the Kr ion laser or Ar ion laser. Further, organic substances such as TPD forming the hole transport layer 16 and Alq3 forming the light emitting layer 18 are difficult to decompose and evaporate depending on the laser beam. However, laser dyes such as rhodamine dyes and coumarin dyes contained in the photoresist layer 14 have a characteristic of absorbing laser light having a wavelength in the visible region. As a result, the photoresist layer 14 containing such a laser dye is decomposed and evaporated by cleavage of the bonds between the molecules by irradiation with laser light having a wavelength in the visible region.
[0018]
Therefore, as shown in FIG. 4, as the photoresist layer 14 is decomposed and evaporated, the hole transport layer 16, the light emitting layer 18, and the Al cathode 20 laminated on the photoresist layer 14 are also formed together with the photoresist layer 14. Removed. That is, only the hole transport layer 16, the light emitting layer 18, and the Al cathode 20 on the photoresist layer 14 patterned into a desired pattern are selectively removed. For example, the hole transport layer 16 is composed of the hole transport layer 16a and the hole transport layer 16b. The light emitting layer 18 is separated into the light emitting layer 18a and the light emitting layer 18b, and the Al cathode 20 is separated into the Al cathode 20a and the Al cathode 20b.
[0019]
And as shown in FIG. 5, the organic EL element 22a which consists of the ITO anode 12, the hole transport layer 16a laminated | stacked on it, the light emitting layer 18a, and the Al cathode 20a, the ITO anode 12, and the hole laminated | stacked on it. The transport layer 16b, the light emitting layer 18b, and the organic EL element 22b including the Al cathode 20b are separately formed. That is, each organic EL element is formed separately according to a desired pattern.
[0020]
As described above, according to the method of manufacturing the organic EL element according to the present embodiment, the photoresist layer 14 patterned in the pattern of the separation region of each organic EL element is formed on the ITO anode 12, and the ITO anode 12 and the photo Using a laser ablation method in which a hole transport layer 16, a light emitting layer 18, and a cathode 20 are sequentially laminated on the resist layer 14, and then the photoresist layer 14 is decomposed and evaporated by irradiating the photoresist layer 14 with a laser beam. By removing the hole transport layer 16, the light emitting layer 18, and the Al cathode 20 laminated thereon together with 14, each organic EL element can be separated.
[0021]
The accuracy with which each organic EL element is separated depends on the accuracy of the pattern of the photoresist layer 14, and the pattern of the photoresist layer 14 can be formed finely and with high accuracy using a photolithography method. It becomes possible to miniaturize each organic EL element with high accuracy. Therefore, in a flat panel display using an organic EL element, it is possible to realize highly precise miniaturization of the pixel.
[0022]
In the method of manufacturing the organic EL element according to the above embodiment, a laser beam is irradiated onto the photoresist layer 14 from the back side of the transparent glass substrate 10 using a high-power laser such as a Kr ion laser or an Ar ion laser. However, the light source for irradiating to decompose and evaporate the photoresist layer 14 is not limited to the laser, and for example, a flash lamp or the like can be used. Moreover, you may irradiate not only the micro area | region of an organic EL element but the wide range of the element whole surface.
[0023]
【The invention's effect】
As described above in detail, according to the method for manufacturing an organic EL element according to the present invention, a resist patterned in a predetermined shape is formed on a transparent electrode, and an organic layer including a light emitting layer is formed on the transparent electrode and the resist. after stacking the layers and a metal electrode layer are sequentially passes through the transparent electrode from the transparent electrode side resist the resist is evaporated by irradiating light to, at the same time the organic layer and a metal electrode layer containing a light-emitting layer on the resist only Each organic EL element can be separated by selectively removing and separating the organic layer including the light emitting layer and the metal electrode layer. At this time, the accuracy with which each organic EL element is separated depends on the patterning accuracy of the resist, and the patterning of the resist layer can be performed finely and with high precision using a photolithography method. Can be miniaturized with high accuracy. Therefore, in a flat panel display using an organic EL element, it is possible to realize highly accurate miniaturization of the pixel.
[Brief description of the drawings]
FIG. 1 is a process cross-sectional view (No. 1) showing a method for manufacturing an organic EL element according to an embodiment of the present invention.
FIG. 2 is a process cross-sectional view (part 2) illustrating the method for manufacturing the organic EL element according to the embodiment of the invention.
FIG. 3 is a process cross-sectional view (part 3) illustrating the method for manufacturing the organic EL element according to the embodiment of the invention.
FIG. 4 is a process cross-sectional view (part 4) illustrating the method for manufacturing the organic EL element according to the one embodiment of the present invention;
FIG. 5 is a process cross-sectional view (part 5) illustrating the method for manufacturing the organic EL element according to the embodiment of the invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Transparent glass substrate, 12 ... ITO anode, 14 ... Photoresist layer, 16, 16a, 16b ... Hole transport layer, 18, 18a, 18b ... Light emitting layer, 20, 20a, 20b ... Al cathode , 22a, 22b: Organic EL elements.

Claims (7)

A first step of forming a resist patterned in a predetermined shape on the transparent electrode; a second step of forming an organic layer including a light emitting layer on the transparent electrode and the resist; and the light emitting layer. A third step of forming a metal electrode layer on the organic layer; and irradiating the resist with light through the transparent electrode from the transparent electrode side to evaporate the resist; and And a fourth step of selectively removing only the organic layer including the light emitting layer and the metal electrode layer, and separating the organic layer including the light emitting layer and the metal electrode layer stacked on the transparent electrode. A method for producing an organic electroluminescent device. 2. The method of manufacturing an organic electroluminescent element according to claim 1, wherein the organic layer including the light emitting layer is a hole transport layer and a light emitting layer that are sequentially stacked. 2. The method of manufacturing an organic electroluminescent element according to claim 1, wherein the organic layer including the light emitting layer is a light emitting layer and an electron transport layer that are sequentially stacked. 2. The method of manufacturing an organic electroluminescent device according to claim 1, wherein the organic layer including the light emitting layer is a hole transport layer, a light emitting layer, and an electron transport layer that are sequentially stacked. Production method. In the manufacturing method of the organic electroluminescent element in any one of Claims 1 thru | or 4, the said resist formed on the said transparent electrode in a said 1st process contains the pigment | dye which absorbs the light of a predetermined wavelength. The method for producing an organic electroluminescent element according to the fourth step, wherein the light applied to the resist has the predetermined wavelength. 6. The method of manufacturing an organic electroluminescent element according to claim 5, wherein the resist material is a heat-resistant polyimide resist mixed with a rhodamine dye or coumarin dye as a laser dye. Manufacturing method of organic electroluminescent element. 6. The method of manufacturing an organic electroluminescent element according to claim 5, wherein the light applied to the resist is a Kr ion laser or an Ar ion laser. The manufacturing method of the organic electroluminescent element characterized by these.

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