JP5036628B2 - Manufacturing method of organic EL display device - Google Patents

Description

  The present invention relates to a method for manufacturing an organic EL display device used for a personal computer, a mobile phone, or the like.

  2. Description of the Related Art Conventionally, an organic EL display device covers an element substrate having a plurality of light emitting portions, covers the sealing substrate with a bonding material, and bonds the mother substrate formed thereby to each individual substrate. It is manufactured by cutting into a display device. In an organic EL display device, a circuit layer on which a driving IC is mounted or an external connection member such as an FPC (Flexible Printed Circuit) is electrically provided on at least one peripheral portion of an element substrate of each display device. The circuit layer connected to is provided (for example, refer to Patent Document 1).

  In such an organic EL display device, the lower electrode layer is desired to be flat. However, a circuit portion provided with various image circuits is provided below the lower electrode layer (element substrate side), and the surface of the circuit portion is not flat. Therefore, for example, a flat surface is provided on the circuit portion by an insulating layer made of an organic photosensitive material or the like, and a lower electrode layer is formed thereon.

  Here, a conventional method for manufacturing an organic EL display device will be briefly described with reference to FIGS. First, the circuit portion 218 including a thin film transistor is formed over the element substrate 212. Then, a lower insulating film 220 is formed so as to cover the circuit portion 218. Next, an insulating film made of an organic material is formed on the lower insulating film 220, and the insulating film is exposed using an exposure mask, and further developed and baked to form a part on the circuit portion 218. A planarizing film 222 having a predetermined shape and having a hole structure is formed.

  Further, a conductive film to be the conductive layer 224 and the lower electrode layer 228 is formed on one surface of the planarization film 222, and a resist is applied on the conductive film. Next, the resist is exposed using an exposure mask, and further developed and baked to obtain a patterned resist having a predetermined shape including the hole structure. Then, the conductive film is etched using the patterned resist as an etching mask, and a lower electrode layer 228 and a second conductive layer 224 having predetermined shapes are formed on the planarization film 222 and the hole structure. This forms a contact portion where the circuit portion 218 and the conductive layer 224 are electrically connected in the hole structure portion.

  Next, an insulating film made of an organic material is formed in a region including on the contact portion, and exposure and development are performed. As shown in FIG. 9, the first insulation that defines the light emitting region of the organic EL display device on the lower electrode layer 228 Layer 226 (edge insulator: EI) is formed.

  Then, an insulating film made of an organic material is formed on the first insulating layer 226, exposed and developed, and a second insulating layer 230 having a predetermined shape is formed on a part of the first insulating layer 226 as shown in FIG. (Rib) is formed.

After that, a mask is placed over the second insulating layer 230, and a light emitting element 232 having a hole injection layer, a light emitting layer made of an organic material, an electron injection layer, and the like is formed by vapor deposition or the like. Next, an upper electrode layer 234 that is electrically connected to the conductive layer 224 is formed over the light-emitting element 232. Then, a protective film 235 made of SiNx, SiO _X , SiN _X Oy or the like is formed on the upper electrode layer 234, and finally the element substrate 212 and the sealing substrate 214 are sealed with a bonding material 236 made of an organic material. The organic EL display device 200 shown in FIG. 11 is manufactured.
Japanese Patent Laying-Open No. 2005-78946

  In the organic EL display device 200 having the above structure, the planarizing film 226 functioning as an edge insulator and the second insulating layer 230 functioning as a rib are both made of an organic material such as a photosensitive resin. And in order to shape | mold into the shape of a predetermined shape, the photolithographic method which has an exposure process, a image development process, a baking process, etc. is used.

  The second insulating layer 230 is for placing a mask or the like for forming the light emitting element 232 and does not need a large area. Therefore, it is formed only in a partial region on the planarizing film 226. As a result, the outer peripheral end portion of the planarizing film 226 is exposed to a developing solution, plasma irradiation, or the like even during the developing process of the second insulating layer 230.

  The adhesion between the conductive layer 224 and the lower electrode 228 made of a metal material and the planarizing film 226 made of a photosensitive resin is not so high. Therefore, there is a problem that the outer peripheral end portion of the planarizing film 226 made of the same photosensitive resin as the second insulating layer 230 is peeled off from the conductive layer 224 and the lower electrode layer 228.

  Therefore, in view of the above problems, the present invention provides an organic EL display device and a method for manufacturing the same that can improve the life of the product by suppressing the peeling of the first insulating layer from the lower electrode layer.

  A method for manufacturing an organic EL display device according to the present invention includes a lower electrode layer, a plurality of light emitting elements formed on the lower electrode layer, an upper electrode layer formed on the light emitting element, and a first insulating layer. And a second insulating layer and a partition disposed between the light emitting elements, and a step of forming the partition includes a photolithography method on the first electrode. The first step of forming a first insulating layer made of a photosensitive resin and the photosensitive resin so that the outer peripheral edge of the first insulating layer is exposed on the first insulating layer by photolithography. And a second step of forming a second insulating layer, and a third step of removing an outer peripheral end of the first insulating layer.

  In the above invention, it is preferable that the third step removes an outer peripheral end portion of the first insulating layer by using a dry etching method.

  In the above invention, the third insulating layer is preferably thicker than the first insulating layer.

  In the above invention, the first insulating layer is an edge insulator that defines an opening range of each light emitting element, and in the first step, the first insulating layer is formed wider than the predetermined opening range, In the third step, it is preferable that the first insulating layer is formed in a predetermined opening range.

  In the above invention, the second insulating layer is preferably a mask for forming the light emitting element or a rib on which a sealing substrate is placed.

  In the above invention, it is preferable that the first insulating layer and the second insulating layer are formed of the same material.

  According to the manufacturing method of the present invention, in the first insulating layer forming step and the second insulating layer forming step, the outer peripheral end portion of the first insulating layer exposed to the developer is removed, whereby the first insulating layer Occurrence of peeling from the lower electrode layer can be suppressed. Therefore, it becomes possible to suppress peeling of the first insulating layer, and the life of the product of the organic EL display device can be improved.

  Hereinafter, an organic EL display device manufactured according to an embodiment of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. Further, the drawings are schematic diagrams for facilitating understanding of the present invention, and may differ from actual dimensions and scales.

  FIG. 1 is a plan view showing a schematic structure of an organic EL display device manufactured according to an embodiment. FIG. 2 is a cross-sectional view showing a schematic configuration in a pixel portion of such an organic EL display device manufactured according to an embodiment.

  The organic EL display device 1 includes an element substrate 12, a plurality of light emitting elements 32 arranged in a matrix on the element substrate 12, and a sealing substrate 14 provided to face the element substrate 12. . On one of the peripheral sides of the element substrate 12, a driver for evenly driving the light emitting element 32 is mounted, and an external connection circuit 50 to which an external connection member such as an FPC is electrically connected is formed. .

  For the element substrate 12 and the sealing substrate 14, glass, quartz, resin, plastic, metal, or the like can be used. In the present embodiment, since the light is extracted from the sealing substrate 14 side, the sealing substrate 14 employs a transparent or translucent material. Further, in the structure in which light is extracted from the element substrate 12 side, it is necessary to use a transparent or translucent material for the element substrate 12.

  On the element substrate 12, a circuit unit 18 including a thin film transistor is formed. A bonding material 16 is provided between the element substrate 12 and the sealing substrate 14 to bond the element substrate 12 and the sealing substrate 14 including a display region having a plurality of light emitting elements 32. Thereby, the display area 10 is sealed in a state of being blocked from outside air. As the bonding material 16, an organic material is used. For example, a photocurable or thermosetting acrylic resin, an epoxy resin, a urethane resin, a silicon resin, or the like can be used.

  A planarizing film 22 made of a material such as an organic material or an inorganic material is provided on the element substrate 12 and the circuit portion 18. The planarizing film 22 functions as a planarizing film for forming the lower electrode layer 28 formed on the planarizing film 22. The planarizing film 22 has a hole structure on the region of the first conductive layer 22 of the circuit unit 18. In addition, when using an organic material as the planarization film | membrane 22, an acrylic resin, a polyimide resin, etc. can be used, for example. In the case of using an inorganic material, silicon oxide, silicon nitride, silicon oxynitride, or the like can be used.

  On the planarizing film 22, a lower electrode layer 28 made of a metal material is formed. A conductive layer 24 made of a metal material is formed on the hole structure. The conductive layer 24 is electrically connected to the circuit unit 18. The circuit portion 18 and the conductive layer 24 in this hole structure function as a contact portion. Note that the lower electrode layer functions as an anode electrode, and a metal such as aluminum, silver, copper, or gold, or an alloy thereof can be used.

  On the lower electrode layer 28, a light emitting element 32 including a hole injection layer, a light emitting layer made of an organic material, an electron injection layer, and the like is provided.

  As the hole injection layer, for example, a material in which polystyrene, polypyrrole, polyaniline, polyacetylene, or a derivative thereof is dispersed in a dispersion medium such as polystyrene sulfonic acid can be used.

  A known light emitting material capable of emitting fluorescence or phosphorescence can be used for the light emitting layer. Further, by providing each light emitting layer of red, green, and blue (R, G, B), an organic EL display device capable of full color display can be obtained. The light emitting layer may be, for example, (poly) fluorene derivative (PF), (poly) paraphenylene vinylene derivative (PPV), polyphenylene derivative (PP), polyparafinylene derivative (PPP), polyvinyl carbazole (PVK), polythiophene derivative or poly Polysilanes such as methylphenylsilane (PMPS) can be used. In addition, these polymer materials can be doped with polymer materials such as perylene dyes, coumarin dyes, rhodamine dyes, and low molecular materials such as rubrene, perylene, tetraphenylbutadiene, quinacridone, and Nile Red. It is.

  Examples of the electron injection layer include LiF (lithium fluoride), NaF (sodium fluoride), KF (potassium fluoride), RbF (rubidium fluoride), CsF (cerium fluoride), and Li2O (lithium oxide). Alkali metal oxides such as Na 2 O (sodium oxide) can be used.

  On the light emitting element 32, an upper electrode layer 34 having a metal material is formed. The upper electrode layers are connected to upper electrode layers formed on adjacent light emitting elements. The upper electrode layer 34 functions as a cathode electrode, and as the material, a light-transmitting conductive material such as an indium tin oxide film (ITO) or a tin oxide film can be used. Moreover, materials, such as magnesium, silver, aluminum, calcium, these alloys, etc. can be used and a light-transmitting electrode can be made by making the thickness into 30 nm or less.

  In a region including the hole structure, a first insulating layer 26 made of a photosensitive organic material is formed. The first insulating layer 26 has a portion filling the inside of the hole structure and a portion formed on the planarizing film 22. As the material of the first insulating layer 26, a photosensitive organic material can be used. Specifically, it is preferable to use a resin containing at least one selected from the group consisting of an acrylic resin, a polyimide resin, and a novolac resin because it is excellent in film formability, durability, and cost.

  A second insulating layer 30 is formed on a part of the first insulating layer 26. As the material of the second insulating layer 30, a photosensitive organic material can be used. In particular, it is preferable to use a resin containing at least one selected from the group consisting of an acrylic resin, a polyimide resin, and a novolac resin because it is excellent in film formability, durability, and cost.

  The first insulating layer 26 and the second insulating layer 30 function as a partition wall disposed between the light emitting elements.

  A protective film 35 for sealing the upper electrode layer 34 is provided on the upper electrode layer 34. The protective film 35 is for preventing the light emitting element 32 from coming into contact with the outside air or moisture, and for example, SiNx can be used. The thickness of the protective film 35 is, for example, 100 nm or more and 5 μm or less.

(Production method)
Next, an embodiment of the method for producing an organic EL display device of the present invention will be described with reference to FIGS. First, the element substrate 12 and the sealing substrate 14 are prepared. At least the element substrate 12 or the sealing substrate 14, for example, a light transmissive substrate such as glass is prepared. Then, a circuit layer 18 on which various circuits including a thin film transistor are formed is formed on the element substrate 12. A driver for lighting the light emitting element 32 is mounted on one of the peripheral sides of the element substrate 12, and an external connection circuit 50 to which an external connection member such as an FPC is electrically connected is formed. . Next, a lower insulating film 20 is formed so as to cover the circuit layer 18 in order to insulate the circuit layer 18.

  Next, an insulating film 22 a made of an organic film is formed on the circuit layer 18 and the lower insulating film 20. The insulating film made of an organic material is exposed and developed using an exposure mask. Thereby, the insulating film 22a not covered with the exposure mask is removed. Next, the element substrate after the exposure process is baked to have a hole structure at a position corresponding to the circuit portion 18 and form the planarizing film 22.

  Subsequently, a conductive film made of a metal material is formed on the planarizing film 22, and a resist is applied on the conductive film. Then, an exposure mask is attached, and an exposure process and a development process are performed on the resist to obtain a predetermined shape. Then, the conductive portion corresponding to the hole structure and electrically connected to the circuit portion 18 and the lower electrode layer 28 functioning as an anode electrode are formed by the etching process. FIG. 3 shows a schematic diagram when the process is completed.

  Next, a method for forming a partition made of the first insulating layer 26 and the second insulating layer will be described. The formation of the partition includes a step of forming the first insulating layer 26, a step of forming the second insulating layer 30, and a step of removing the outer peripheral end portion of the first insulating layer 26. The process will be described in detail below.

  A process of forming the first insulating layer 26 will be described with reference to FIGS. The first insulating layer 26 is formed in a predetermined shape by using a photolithography method including an exposure process, a development process, and a baking process. Specifically, an insulating film 26a made of Optomer NN700G or Optomer PC415G manufactured by JSR Co. is formed on the lower electrode layer 28, covered with the exposure mask 60, and an exposure process is performed. The exposure mask 60 used had a low light transmittance at a portion corresponding to a portion functioning as a rib and a high light transmittance at other portions. Thereafter, a developing process is performed using a developer to remove unnecessary portions of the insulating film 26a, and a baking process is performed to form a first insulating layer 26 having a predetermined shape as shown in FIG. In addition, it is preferable that the thickness of the part which functions as a rib is 0.4 micrometer-2.0 micrometers, and the thickness of another part is 0.2 micrometer-1.0 micrometer. The first insulating layer 26 functions as an edge insulator that defines the opening range of each light emitting element 32. In this step, the dummy portion A is formed on the outer periphery of the defined opening range. That is, the first insulating layer 26 is formed with an area wider than the defined opening range. The dummy portion A is preferably formed in the range of about 0.1 μm to 2.0 μm on the outer periphery of the opening range. When formed in this range, removal in a later step is facilitated, and the influence on the outer peripheral end of the second insulating layer 30 in the step of removing the outer peripheral end of the first insulating layer 26 can be reduced. it can.

  In this embodiment, the development process is performed using TMAH (tetramethylammonium hydroxide: 0.48%) as a developer. However, not limited to this, so-called dry etching using plasma irradiation or the like is used. Is also possible.

  Next, the process of forming the second insulating layer 30 will be described with reference to FIGS. Similar to the formation of the first insulating layer 26, the second insulating layer 30 is formed in a predetermined shape by using a photolithography method having an exposure process, a developing process, and a baking process. On the first insulating layer 26, an insulating film 30a made of an optomer NN700G or an optomer PC415G made of an organic material JSR, which is the same material as the first insulating layer 26, is formed. Then, an exposure process is performed by covering the portion corresponding to the light emitting region with the exposure mask 70 so that light is irradiated. Thereafter, a developing process is performed using a developing solution to remove unnecessary portions of the insulating film 26a, and a baking process is performed to form a second insulating layer 30 having a predetermined shape as shown in FIG. The second insulating layer 30 functions as a mask for forming a light emitting element 32 to be formed later or a rib on which the sealing substrate 14 attached thereafter is placed. Therefore, it is sufficient that the mask or the like can be placed, and the area is smaller than that of the first insulating layer 26. The thickness of the second insulating layer 30 is preferably about twice that of the first insulating layer 26, and specifically, it is preferably about 0.5 μm to 2.0 μm. Further, for the portion functioning as a rib, the total thickness of the first insulating layer 26 and the second insulating layer 30 is preferably 1.5 μm to 4.0 μm.

  In the manufacturing process described above, the outer peripheral end portion (that is, the dummy portion A) of the first insulating portion 26 has undergone two development steps, so that the lower electrode layer 28 that does not have high adhesion may float or peel off. There is a possibility.

  Therefore, a step of removing the outer peripheral end portion (that is, the dummy portion A) of the first insulating layer 26 is performed. As the removal step, a photolithography method including an exposure step, a development step, and a baking step, an etching method using an etching solution, or the like can be used, and a dry etching method is particularly preferable. This etching method refers to a method in which an organic material having photosensitivity is removed by reacting oxygen gas or oxygen gas and other etching gas under plasma. As the etching gas, oxygen or fluorine-based gas such as SF6 or CF4 is often used, but is not limited thereto. As the dry etching method, a plasma etching method, a reactive ion etching method, an ICP method, a chemical dry etching method, or the like is used. The use of this method is preferable because the influence on the outer peripheral edge of the second insulating layer 30 is small compared to the case where other methods are used.

  The step of removing the outer peripheral end portion (dummy portion A) of the first insulating layer 26 will be described below. The second insulating layer 30 is used as a mask, and oxygen gas is injected into the first insulating layer 26. Then, the dummy part A which may have peeled off or floated is removed. At this time, a part of the second insulating layer 30 is partially removed, but the first insulating layer 26 located immediately below the second insulating portion 30 is not removed. Thus, the first insulating layer 26 has a predetermined shape of the light emitting element 32 and functions as an edge insulator that defines the opening range. FIG. 8 shows after the process.

  The second insulating layer 30 is preferably thicker than the first insulating layer 26. The second insulating layer 30 functions as a mask for the first insulating layer 26 in the step of removing the outer peripheral edge of the first insulating layer 26. Therefore, even if a part of the second insulating layer 30 is removed in this step, the influence on the function as a rib can be reduced.

  The peeling at the outer peripheral edge between the first insulating film 26 and the lower electrode is caused by variations in the photolithography process, but is about 1 μm in length. That is, the outer peripheral end portion of the first insulating film 26 that is easily peeled is projected from the second insulating layer 30 in advance, and then removed by dry etching or the like using the second insulating film 30 as a mask. It is possible to remove the portion and form a complete opening in the adhesion.

  Further, as in the embodiment, by forming the first insulating layer 26 and the second insulating layer 30 from the same photosensitive resin, the manufacturing apparatus can be simplified and the manufacturing time can be shortened. In addition, since the thermal expansion coefficient is substantially the same, the structure is stable against thermal stress and mechanical stress. In addition, when the developing process is performed with a developer, the same developer can be used, and material costs can be reduced and the manufacturing apparatus can be simplified. Further, even when the first insulating layer 26 and the second insulating layer 30 are made of different photosensitive resins, if the developing process is performed with the same developer, the manufacturing apparatus can be simplified and the manufacturing time can be shortened. It becomes possible.

  After the above process, a light emitting element 32 including a hole injection layer, a light emitting layer made of an organic material, an electron injection layer, and the like is formed on the lower electrode layer 28. The light emitting element 32 is formed, for example, by depositing the above-described predetermined material by vapor deposition or the like using a predetermined mask.

Then, an upper electrode layer 34 made of a material such as magnesium or silver is formed on the light emitting element 32 as a cathode electrode. Then, after sealing the upper electrode layer 34 with a protective film 35 made of SiNx, SiO _X , SiN _X Oy or the like, the element substrate 12 and the sealing substrate 14 are bonded by the bonding material 16, as shown in FIG. An organic EL display device was manufactured.

  The organic EL display device according to the present invention can be used as a display unit of a portable information terminal such as a mobile phone or a personal computer. By using the present invention, the product life of the organic EL display device can be improved. Therefore, the product life of an electronic device including the organic EL display device can be improved.

It is a top view which shows schematic structure of the organic electroluminescent display apparatus concerning one Embodiment of this invention. It is sectional drawing which shows the schematic sectional drawing in the pixel part of the organic electroluminescence display concerning one Embodiment of this invention. It is a schematic sectional drawing explaining the manufacturing process of the organic electroluminescent display apparatus concerning one Embodiment of this invention. It is a schematic sectional drawing explaining the manufacturing process of the organic electroluminescent display apparatus concerning one Embodiment of this invention. It is a schematic sectional drawing explaining the manufacturing process of the organic electroluminescent display apparatus concerning one Embodiment of this invention. It is a schematic sectional drawing explaining the manufacturing process of the organic electroluminescent display apparatus concerning one Embodiment of this invention. It is a schematic sectional drawing explaining the manufacturing process of the organic electroluminescent display apparatus concerning one Embodiment of this invention. It is a schematic sectional drawing explaining the manufacturing process of the organic electroluminescent display apparatus concerning one Embodiment of this invention. It is a schematic sectional drawing explaining the manufacturing process of the conventional organic electroluminescent display apparatus. It is a schematic sectional drawing explaining the manufacturing process of the conventional organic electroluminescent display apparatus. It is a schematic sectional drawing explaining the manufacturing process of the conventional organic electroluminescent display apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic EL display device 10 Display area | region 12 Element board | substrate 14 Sealing board | substrate 16 Bonding material 18 Circuit part 20 Lower insulating layer 22 Planarization film 24 Conductive layer 26 1st insulating layer 26a Insulating film 28 Lower electrode layer 30 2nd insulating layer 30a Insulating layer 32 Light emitting element 34 Upper electrode layer 35 Protective film 50 External connection circuit 60, 70 Exposure mask A Dummy part

Claims (7)

A lower electrode layer; a plurality of light emitting elements formed on the lower electrode layer; an upper electrode layer formed on the light emitting element; a first insulating layer and a second insulating layer; A method of manufacturing an organic EL display device comprising a partition wall disposed therebetween,
The step of forming the partition includes
A first step of forming a first insulating layer made of a photosensitive resin on the first electrode by a photolithography method;
A second step of forming a second insulating layer made of a photosensitive resin on the first insulating layer by a photolithography method so that an outer peripheral end of the first insulating layer is exposed;
A third step of removing the outer peripheral edge of the first insulating layer;
An organic EL display device manufacturing method comprising:   2. The method of manufacturing an organic EL display device according to claim 1, wherein in the third step, an outer peripheral end portion of the first insulating layer is removed using a dry etching method.   3. The method of manufacturing an organic EL display device according to claim 2, wherein the third step uses the second insulating layer as a mask and removes an outer peripheral end portion of the first insulating layer.   4. The method of manufacturing an organic EL display device according to claim 1, wherein the second insulating layer is thicker than the first insulating layer. 5. The first insulating layer is an edge insulator that defines an opening range of each light emitting element,
In the first step, the first insulating layer is formed wider than the predetermined opening range,
5. The method of manufacturing an organic EL display device according to claim 1, wherein, in the third step, the first insulating layer is formed in a predetermined opening range.   The organic EL display device according to claim 1, wherein the second insulating layer is a mask for forming the light emitting element or a rib on which a sealing substrate is placed. Production method. The method for manufacturing an organic EL display device according to claim 1, wherein the first insulating layer and the second insulating layer are formed of the same material.

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