JP2011060738A - Method of manufacturing organic el panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an organic EL panel, which uses a base with wires using an Al-Ni alloy while improving the quality and yield. <P>SOLUTION: The organic EL panel includes the base 1 on which wiring parts 4, 5 are formed including a conductor layer 5b containing at least aluminum and nickel, and a light-emitting part formed thereon and having at least a hole injection layer and an organic light-emitting layer held between a first electrode 6 formed on the side of the base 1 and a second electrode 10 opposed to the first electrode 6, the wiring parts 4, 5 being electrically connected to at least one of the first and second electrodes 6, 10. The method of manufacturing the same includes forming at least wiring parts 4, 5 and forming the hole injection layer in a wetting step, and then heating the base 1 to reduce the resistivity of the wiring parts 4, 5. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an organic EL (electroluminescence) panel using a substrate with wiring.

  2. Description of the Related Art Conventionally, an organic EL panel including an organic EL element that is a self-luminous element formed of an organic material includes, for example, a first electrode made of indium tin oxide (ITO) or the like serving as an anode, and an organic layer including an organic light emitting layer And a non-translucent second electrode made of aluminum (Al) or the like serving as a cathode are sequentially stacked to form an organic EL element (see, for example, Patent Document 1). Such an organic EL panel emits light by injecting holes from the first electrode and injecting electrons from the second electrode, and the holes and electrons recombine in the light emitting layer, and has excellent visibility. Therefore, it is used in in-vehicle instruments and mobile communication terminals that require instantaneous interpretation because of its excellent high-speed response at low temperatures.

  In the organic EL element, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are appropriately stacked as an organic layer. The film formation method differs depending on whether the organic layer is a low-molecular material or a high-molecular material. The low-molecular material film formation process is a dry process in which vapor deposition is mainly used. This is a wet process in which a coating method, an ink jet method, a spray method, or the like is used (for example, see Patent Document 2).

  By the way, the passive matrix type organic EL panel requires a predetermined light emission current, and the light emission luminance increases in proportion to the current density. However, since the voltage drop occurs due to the resistance of the wiring, it is necessary to reduce the resistance of the wiring portion. It is said that. However, there is a limit to reducing the resistance of the ITO layer conventionally used for wiring materials. Thus, it is known that the resistance of the organic EL element circuit can be further reduced by combining a low resistance metal such as aluminum (Al) or Al alloy with the ITO layer as an auxiliary wiring. For example, Cited Document 3 discloses an Al—Ni alloy containing nickel (Ni) in Al as an Al alloy.

JP 59-194393 A Japanese Patent Laid-Open No. 2003-113069 JP 2007-142356 A

  In order to reduce the resistivity of the Al—Ni alloy, it is necessary to perform a heat treatment by heating at a temperature of, for example, 200 ° C. or higher after film formation. However, when a wet process is performed in the manufacture of an organic EL panel, the Al—Ni alloy particles formed in the wiring by heat treatment are released from the wiring to the light emitting part, thereby causing display abnormality and display defect. There was a problem that the quality deteriorated and the yield decreased. Examples of the wet process include a cleaning process performed after the formation of the insulating film and partition walls defining the light-emitting pixels and a film forming process of a polymer material. Even when the cap layer is formed on the Al—Ni alloy, there is a problem in that the patterning after the heat treatment causes the release of the Al—Ni alloy particles from the end portion of the wiring.

  The present invention has been made in view of this problem, and manufacture of an organic EL panel capable of improving quality and yield in an organic EL panel using a substrate with wiring using a low-resistance Al—Ni alloy. It is intended to provide a method.

  In order to solve the above problems, the present invention provides a first electrode formed on the substrate side on the substrate on which a wiring portion including a conductor layer containing at least aluminum and nickel is formed, and the first electrode A light emitting part is formed by sandwiching at least the hole injection layer and the organic light emitting layer with the opposing second electrode, and the wiring part is electrically connected to at least one of the first and second electrodes. A method of manufacturing an organic EL panel comprising: forming at least the wiring portion, forming the hole injection layer in a wet process, and then performing a heat treatment to heat the base and lower the resistivity of the wiring portion It is characterized by.

  The organic EL panel includes an insulating film formed on the base so as to cover at least an end portion of the first electrode, and a partition formed so as to separate the second electrode into a plurality of parts. After the formation of at least the wiring portion, the insulating film, the partition wall, and the hole injection layer, a heat treatment is performed to heat the substrate and lower the resistance of the wiring portion.

  Further, the wiring portion is characterized in that a cap layer containing molybdenum or a molybdenum alloy is formed on the conductor layer.

  Further, the wiring portion is formed by forming a transparent conductor layer between the base and the conductor layer.

  Further, the wiring portion is formed by forming a cap layer containing molybdenum or a molybdenum alloy between the transparent conductor layer and the conductor layer.

  The wiring portion is a wiring for electrically connecting at least one of the first and second electrodes and a drive circuit.

  The present invention can improve quality and yield in an organic EL panel using a substrate with wiring using an Al-Ni alloy.

The rear view of the organic electroluminescent panel in embodiment of this invention. The principal part enlarged view of the organic electroluminescent panel in embodiment same as the above. Sectional drawing which shows the organic electroluminescent panel in embodiment same as the above. Sectional drawing which shows the principal part which shows the organic electroluminescent panel in embodiment same as the above. The figure which shows the manufacturing method of the support substrate with wiring and organic electroluminescent panel of embodiment same as the above.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that these descriptions, drawings, and the like exemplify the present invention and do not limit the scope of the claims. It goes without saying that other embodiments may belong to the category of the present invention as long as they match the gist of the present invention.

  FIG. 1 is a diagram showing an organic EL panel. The organic EL panel includes a support substrate (base) 1, a light emitting region 2, a driver IC (drive circuit) 3, an anode wiring portion 4, and a cathode wiring portion 5.

  The support substrate 1 is an electrically insulating substrate with wiring made of a rectangular transparent glass material. On the support substrate 1, a light emitting region 2, a driver IC 3, an anode wiring part (wiring part) 4, and a cathode wiring part (wiring part) 5 are formed. Further, a sealing member that covers the light emitting region 2 in an airtight manner is disposed on the support substrate 1, but the sealing member is omitted in FIGS. 1 and 2.

  As shown in FIGS. 2 and 3, the light emitting region 2 includes a plurality of anodes (first electrodes) 6 formed in a line, an insulating film 7, a partition wall 8, an organic layer 9, and a plurality of lines. A cathode (second electrode) 10 to be formed is formed. That is, in the organic EL panel, each anode 6 and each cathode 10 intersect, and a plurality of light emitting portions (organic EL elements) each having an organic layer 9 sandwiched between the anode 6 and the cathode 10 are arranged in a matrix. Is. The anode 6 and the cathode 10 are electrically connected to the driver IC 3 through the anode wiring part 4 and the cathode wiring part 5. In addition, each of the light emitting portions is airtightly covered with a sealing member 11 as shown in FIG.

  The driver IC 3 constitutes a drive circuit that drives the light emitting units in the light emitting region 2 and includes a signal line drive circuit, a scanning line drive circuit, and the like. The driver IC 3 is disposed on the support substrate 1 by COG (Chip On Glass) technology, and is electrically connected to each anode 6 and each cathode 10 through the anode wiring portion 4 and the cathode wiring portion 5.

  The anode wiring part 4 and the cathode wiring part 5 are members for electrically connecting the anode 6 and the cathode 10 and the driver IC 3 respectively. The anode wiring portion 4 and the cathode wiring portion 5 include a transparent conductor layer formed on the support substrate 1, a first cap layer made of molybdenum (Mo) or an Mo alloy, aluminum (Al) and at least nickel (Ni ) Containing a conductor layer made of an Al—Ni alloy compound and a second cap layer made of molybdenum (Mo) or Mo alloy. FIG. 3 shows a cathode wiring portion 5, which includes a transparent conductor layer 5 a, a first cap layer 5 b, a conductor layer 5 c, and a second cap layer 5 d on the support substrate 1. It is formed by stacking. Although not shown, the anode wiring portion 4 has a similar laminated structure, and a transparent conductor layer such as ITO, a first cap layer, a conductor layer, and a second cap layer are formed by lamination from the anode 6. Being done.

  The transparent conductor layer 5 a is made of, for example, ITO, IZO, ZnO, or the like, which is the same material as the anode 6, and is formed on the support substrate 1 in the same process as the anode 6.

  The first cap layer 5b is made of Mo or Mo alloy, and is formed between the transparent conductor layer 5a and the conductor layer 5c in order to prevent Al oxide from being formed on the conductor layer 5b. is there. Examples of the Mo alloy include Ni-Mo, Mo-niobium (Nb), Mo-tantalum (Ta), Mo-vanadium (V), and Mo-tungsten (W). The cap layer 5c preferably has a thickness of 10 to 100 nm from the viewpoint of patterning properties.

  The conductor layer 5b is made of an Al—Ni alloy, and is formed on the transparent conductor layer 5a of the support substrate 1 in order to reduce the resistance of the wiring. The conductor layer 5b preferably has a thickness of 100 to 500 nm so that sufficient conductivity and good patterning can be obtained. The conductor layer 5b may further contain another metal material such as boron (B). Further, the Al—Ni alloy can be directly bonded to the transparent conductor layer 5a, and the first cap layer 5b may be omitted.

  The second cap layer 5c is made of Mo or Mo alloy, and is formed on the conductor layer 5b in order to protect the conductor layer 5b from corrosion. Examples of the Mo alloy include Ni-Mo, Mo-niobium (Nb), Mo-tantalum (Ta), Mo-vanadium (V), and Mo-tungsten (W). The cap layer 5c preferably has a thickness of 10 to 100 nm from the viewpoint of moisture resistance and patterning properties.

  The anode 6 is made of a transparent conductive material such as ITO. After the transparent conductive material is formed in layers on the support substrate 1 by means of vapor deposition or sputtering, it is formed in a line shape so as to be substantially parallel to each other by photoetching or the like. A plurality are formed. Further, the anode 6 is connected to the driver IC 3 through an anode wiring portion 4 extending from one side of the end portion (lower side in FIG. 1).

  The insulating film 7 is made of, for example, a polyimide-based electrically insulating material, and is formed on at least the end of the anode 6 so as to be positioned between the anode 6 and the cathode 10, thereby preventing a short circuit between the electrodes 6 and 10. In addition, it has an opening 7a that defines each light emitting portion of the light emitting region 2. The insulating film 7 is also extended between the cathode wiring part 5 and the cathode 10 and has a contact hole 7 b for connecting the cathode wiring part 5 and the cathode 10.

  The partition wall 8 is made of, for example, a phenol-based electrically insulating material and is formed on the insulating film 7. The partition wall 8 is formed by means such as photoetching so that the cross section thereof has a reverse taper shape with respect to the insulating film 7. A plurality of partition walls 8 are formed at equal intervals in a direction orthogonal to the anode 6. The partition wall 8 separates the organic layer 9 and the metal film into a plurality in the direction orthogonal to the anode 6 when forming a metal film to be the organic layer 9 and the cathode 10 from above by a vapor deposition method or a sputtering method. is there.

  The organic layer 9 is formed on the anode 6 and has at least a hole injection layer and an organic light emitting layer. In the present embodiment, as shown in FIG. 4, the organic layer 9 is formed by sequentially stacking a hole injection layer 9a, a hole transport layer 9b, an organic light emitting layer 9c, an electron transport layer 9d, and an electron injection layer 9e. It will be. Of the organic layer 9, the hole injection layer 9a formed on the anode 6 is made of a polymer material and formed in a wet process using a coating method, a spin coating method, an ink jet method, a spray method, or the like. In addition, the hole transport layer 9b, the organic light emitting layer 9c, the electron transport layer 9d, and the electron injection layer 9e are formed by a dry process using a vapor deposition method.

  For the cathode 10, a plurality of metallic conductive materials having higher conductivity than the anode 6 such as aluminum (Al) and magnesium silver (Mg: Ag) are formed in a line shape so as to intersect the anode 6 by means such as vapor deposition. It will be. The cathode 10 is formed by separating the conductive material into a plurality by the partition wall 8 during film formation. The cathode 10 is connected to the cathode wiring portion 5 through a contact hole 7 b provided in the insulating film 7, and is electrically connected to the driver IC 3 through the cathode wiring portion 5.

  The sealing member 11 is a flat plate member made of, for example, a glass material, and includes a concave portion 11a that houses each light emitting portion of the light emitting region 2 and a joint portion 11b that is formed so as to surround the entire circumference of the concave portion 11a. And disposed on the support substrate 1 via an adhesive 11c.

  The organic EL panel is configured by the above-described units.

  Next, an example of a method for manufacturing an organic EL panel will be described with reference to FIG.

  First, in the anode etc. forming step S1, ITO is formed in a layer thickness of 150 nm on the support substrate 1 by means such as sputtering, and then patterned by photoetching or the like to form the transparent conductor layer and cathode of the anode wiring portion 4 The transparent conductor layer 5a and the anode 6 of the wiring part 5 were formed.

  Next, in the wiring portion forming step S2, a film of Mo with a film thickness of 20 nm, an Al—Ni alloy with a film thickness of 360 nm, and a film of Mo with a film thickness of 20 nm were formed on the cleaned support substrate 1 by sputtering. The resistivity of the laminate immediately after sputtering is as high as about 10 μΩ / cm. Thereafter, patterning is performed by photoetching, and the first cap layer, the conductor layer, and the second cap layer of the anode wiring portion 4 and the first cap layer 5b, the conductor layer 5c, and the second cap layer 5d of the cathode wiring portion 5 are formed. Formed. Thereby, the support substrate 1 with wiring which has the anode wiring part 4 and the cathode wiring part 5 as wiring is obtained. At this time, the temperature used in photolithography is set to 100 ° C. or less, so that the anode wiring portion 4 and the cathode wiring portion 5 maintain the composition and structure immediately after sputtering.

  Next, in the insulating film forming step S3, a photosensitive polyimide film is spin-coated on the support substrate 1, and then patterned by photoetching to form the insulating film 7 having the opening 7a and the contact hole 7b in the light emitting region 2 with a film thickness. Formed at 1.0 μm.

  Next, in the partition formation step S4, a photosensitive acrylic resin was spin-coated on the support substrate 1, and then patterned by photoetching to form a partition 8 perpendicular to the anode 6 on the insulating film 7. After the partition walls were formed, the support substrate 1 that was a wet process was cleaned.

  Next, argon plasma irradiation is performed using a parallel plate RF plasma apparatus to modify the surface of the ITO film, and in the hole injection layer forming step S5, a positive thickness of 150 nm is formed on the support substrate 1 by spin coating. Hole injection layer 9a was formed. Specifically, polyethylene dioxythiophene (PEDOT: PSS) doped with polystyrene sulfonic acid was formed using a spin coater. Therefore, the hole injection layer forming step S5 is a wet step.

Immediately after the formation of the hole injection layer 9a, the support substrate 1 was heated in the heat treatment step S6 to perform the heat treatment. In the heat treatment step S6, the conductor layer and the conductor layer 5b are made into an Al—Ni alloy so that the resistivity becomes a desired value, the insulating film 7 and the partition wall 8 are dehydrated, and the hole injection layer 9a is fired. Solidification is performed at the same time. Therefore, the heating temperature in the heat treatment step S6 does not cause thermal damage to the insulating film 7, the partition wall 8 and the hole injection layer 9a, and the conductor layer of the anode wiring part 4 and the conductor layer 5b of the cathode wiring part 5 The temperature needs to be capable of lowering the resistivity. In this example, the support substrate 1 was subjected to vacuum heat dehydration treatment at 200 ° C. for 1 hour in an environment of 5.0 × 10 ⁻⁴ Pa. By the heat treatment, the resistivity of the anode wiring portion 4 and the cathode wiring portion 5 was reduced, and a desired resistivity was obtained. The heating temperature and the heating time are appropriately set depending on the materials of the insulating film 7, the partition wall 8, and the hole injection layer 9a.

Then, a hole transport layer 9b, an organic light emitting layer 9c, an electron transport layer 9d, and an electron injection layer 9e are stacked using a vapor deposition device so as to correspond to the anode 6 in the hole transport layer to electron injection layer formation step S7. Further, in the cathode forming step S8, the cathode 10 was laminated and formed on the organic layer 9 using a vapor deposition device to obtain the light emitting portions. Specifically, NPD is formed with a film thickness of 30 nm as the hole transport layer 9b, Alq _{3 is formed} with a film thickness of 30 nm as the organic light emitting layer 9c, and BCP is formed with a film thickness of 20 nm as the electron transport layer 9d. Then, lithium fluoride (LiF) was formed to a thickness of 0.5 nm as the electron injection layer 9e, and Al was formed to a thickness of 150 nm as the cathode 10.

  And in sealing process S9, the sealing member 11 which has the recessed part 11a which covers the light emission area | region 2 was prepared, and it was arrange | positioned and fixed on the support substrate 1 via the ultraviolet curable adhesive 11c. It is desirable that a moisture absorbent (not shown) that adsorbs moisture is disposed on the surface of the recess 11a facing the light emitting units. The organic EL panel having the light emitting region 2 was obtained by the above manufacturing process.

(Comparative example)
Next, the manufacturing method of the organic electroluminescent panel as a comparative example is demonstrated. In the comparative example, the heat treatment step S6 is not performed, and the support substrate 1 is formed at 200 ° C. for 30 minutes after the formation of the anode wiring part 4 and the cathode wiring part 5 for the purpose of reducing the resistance of the anode wiring part 4 and the cathode wiring part 5. The heat treatment to be performed was performed in a nitrogen environment, and after the formation of the hole injection layer 9a, vacuum heat dehydration was performed at 200 ° C. for 1 hour in an environment of 5.0 × 10 ⁻⁴ Pa. About other processes, it carried out similarly to the Example, and obtained the organic electroluminescent panel.

  Table 1 below shows the yield of the examples and comparative examples.

  It was confirmed that the organic EL panel obtained by the manufacturing process according to the example did not cause display abnormality or display defect and improved in quality and yield. On the other hand, in the organic EL panel obtained in the manufacturing process according to the comparative example, Al—Ni alloy particles flowed onto the light emitting portion, causing display abnormalities and display defects, and the yield was significantly reduced. Conventionally, the decrease in the quality and yield of the organic EL panel is considered to be caused by Al—Ni alloy particles formed in the wiring by the heat treatment flowing into the light emitting part by the wet process. The inventor of the present application pays attention to this point, and in the manufacturing process of the organic EL panel, after the formation of the hole injection layer 9a obtained by the wet process, by performing heat treatment to lower the resistivity of the conductor layer and the conductor layer 5b, It has been found that even when Al—Ni alloy particles start to be generated, the hole injection layer 9a is solidified, so that the Al—Ni alloy particles are not liberated and the quality and yield can be improved. It is clear from the results in Table 1 that the present invention has a sufficient effect.

  In the present embodiment, the cathode wiring portion 5 is composed of a laminate of the transparent conductor layer 5a, the conductor layer 5b, and the cap layer 5c, and the anode wiring portion 4 is also composed of the same laminated structure. In the present invention, the wiring portion only needs to include a conductor layer made of at least an Al-Ni alloy, and the transparent conductor layer may not be formed, and the conductor layer may be formed directly on the substrate. The cap layer may not be formed.

  The present invention relates to a method for manufacturing an organic EL panel, and more particularly to a method for manufacturing an organic EL panel using a substrate with wiring using an Al—Ni alloy.

DESCRIPTION OF SYMBOLS 1 Support substrate 2 Light emission area 3 Driver IC
DESCRIPTION OF SYMBOLS 4 Anode wiring part 5 Cathode wiring part 5a Transparent conductor layer 5b 1st cap layer 5c Conductive layer 5d 2nd cap layer 6 Anode 7 Insulating film 7a Opening part 7b Contact hole 8 Partition 9 Organic layer 10 Cathode 11 Sealing member

Claims (6)

On a base on which a wiring part including a conductor layer containing at least aluminum and nickel is formed, at least a hole injection layer with a first electrode formed on the base and a second electrode facing the first electrode And forming a light emitting part sandwiching the organic light emitting layer, and the wiring part is a method for manufacturing an organic EL panel electrically connected to at least one of the first and second electrodes,
A method of manufacturing an organic EL panel, comprising: forming at least the wiring part, and forming the hole injection layer in a wet process, and then performing a heat treatment for heating the substrate to lower the resistivity of the wiring part. The organic EL panel includes an insulating film formed so as to cover at least an end of the first electrode and a partition formed so as to separate the second electrode into a plurality of parts on the base. And
2. The organic EL according to claim 1, wherein after the formation of at least the wiring portion, the insulating film, the partition wall, and the hole injection layer, a heat treatment for reducing the resistance of the wiring portion by heating the substrate is performed. Panel manufacturing method. 2. The method of manufacturing an organic EL panel according to claim 1, wherein the wiring portion is formed by forming a cap layer containing molybdenum or a molybdenum alloy on the conductor layer. 2. The method of manufacturing an organic EL panel according to claim 1, wherein the wiring portion is formed by forming a transparent conductor layer between the base and the conductor layer. 5. The method of manufacturing an organic EL panel according to claim 4, wherein the wiring portion is formed by forming a cap layer containing molybdenum or a molybdenum alloy between the transparent conductor layer and the conductor layer. 2. The method of manufacturing an organic EL panel according to claim 1, wherein the wiring portion is a wiring for electrically connecting at least one of the first and second electrodes and a drive circuit.

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