JP2017188345A - Method of manufacturing light emitting panel and light emitting panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize film quality of a cathode as a translucent electrode even if the size of a substrate at a time of forming the cathode is increased.SOLUTION: The method for manufacturing a light emitting panel in which an anode 13, a light emitting layer 17, and a cathode 20 are formed in this order above a substrate 11, includes forming the cathode so as to have light transmissibility by a sputtering method using a target containing silver as a main component and copper.SELECTED DRAWING: Figure 7

Description

  The present disclosure relates to a method for manufacturing a light emitting panel and a light emitting panel, and more particularly, to a method for manufacturing a cathode that is a transparent electrode of a top emission type light emitting panel, and a manufactured cathode.

  Flat displays such as liquid crystal displays and organic EL (Electro-Luminescence) display devices are widely used. Such a light emitting panel generally has a configuration in which a light emitting layer is disposed between an anode and a cathode. In particular, a so-called top emission type light emitting panel has the following structure. A light-reflective conductive material such as silver (Ag) or aluminum (Al) is used for the electrode on the substrate side in order to reflect the light from the light emitting layer to the side from which the light is extracted to increase the light extraction efficiency. On the other hand, a translucent conductive material is used for the electrode from which light is extracted in order to efficiently extract light emitted from the light emitting layer to the outside. Conventionally, for example, a metal oxide (ITO: Indium Tin Oxide) is used as the light-transmitting conductive material (for example, Patent Document 1).

  An electrode formed using a light-transmitting material (hereinafter referred to as “translucent electrode”) is required to have both low resistance and high transmittance. Therefore, in addition to metal oxides, metal thin films have been studied. The translucent electrode is required to have a uniform film quality in order to transmit light more efficiently and to make characteristics such as resistivity constant. Therefore, formation by vapor deposition or sputtering is performed.

JP 2014-140048 A

  An object of the present disclosure is to provide a method for manufacturing a light-emitting panel and a light-emitting panel that improve uniformity of film quality when forming a metal thin film mainly composed of silver as a translucent electrode.

  A manufacturing method of a light-emitting panel according to one embodiment of the present disclosure is a manufacturing method in which a light-emitting panel is formed in the order of an anode, a light-emitting layer, and a cathode above a substrate, and a target containing silver as a main component and copper is used. The cathode is formed by sputtering so as to have optical transparency.

  According to the manufacturing method of the light emitting panel of the said aspect, even if the board | substrate size at the time of cathode formation becomes large, the film quality of the cathode as a translucent electrode can be stabilized.

It is sectional drawing which shows typically the structure of the light emission panel 100 which concerns on embodiment. It is a fragmentary sectional view showing typically a part of manufacturing process of luminescent panel 100 concerning an embodiment. (A) is a fragmentary sectional view which shows the state in which the TFT layer was formed on the base material. (B) is a partial cross-sectional view showing a state in which an interlayer insulating layer is formed on the TFT layer. (C) is a fragmentary sectional view which shows the state in which the barrier metal material layer was formed on the interlayer insulation layer. (D) is a fragmentary sectional view which shows the state in which the lower electrode layer was formed on the barrier metal material layer. (E) is a fragmentary sectional view which shows the state in which the positive hole injection material layer was formed on the lower electrode layer. (F) is a partial cross-sectional view showing a state in which a barrier metal material layer, a lower electrode material layer, and a hole injection material layer are patterned to form a lower electrode and a hole injection layer. It is a fragmentary sectional view showing typically a part of manufacturing process of luminescent panel 100 concerning an embodiment. (A) is a fragmentary sectional view which shows the state by which the partition material layer was formed on the positive hole injection layer and the interlayer insulation layer. (B) is a partial sectional view showing a state in which a partition wall layer is formed by patterning a partition wall material layer. (C) is a partial cross-sectional view showing a state in which a hole transport layer is formed in the opening of the partition wall layer. (D) is a fragmentary sectional view showing a state in which a light emitting layer is formed on the hole transport layer in the opening of the partition wall layer. It is a fragmentary sectional view showing typically a part of manufacturing process of luminescent panel 100 concerning an embodiment. (A) is a fragmentary sectional view which shows the state in which the electron carrying layer was formed on the partition layer and the light emitting layer. (B) is a fragmentary sectional view showing a state where an electron injection layer is formed on the electron transport layer. (C) is a partial sectional view showing a state in which an upper electrode and a sealing layer are formed on the electron injection layer. It is a flowchart which shows the manufacture process of the light emission panel 100 which concerns on embodiment. It is a schematic diagram which shows the sputtering device 500 used for manufacture of the upper electrode 20 which concerns on embodiment. (A)-(d) is an electron micrograph of the surface of the upper electrode 20 which concerns on embodiment. (E) is a figure which shows the sheet resistance value of the upper electrode 20 which concerns on embodiment. (A), (b) is a figure which shows the light transmittance of the upper electrode 20 which concerns on embodiment. It is a cross-sectional photograph of the silver thin film produced | generated by the vapor deposition system. It is a schematic block diagram which shows schematic structure of the organic electroluminescence display which concerns on embodiment.

<Background to the Aspect of the Present Disclosure>
A light-transmitting electrode of a light-emitting panel requires high visible light transmittance and low electrical resistance. Therefore, it has been studied to use a thin film of silver (Ag) with high electrical conductivity as a translucent electrode. In order to use a silver thin film as a translucent electrode, the film thickness must be about 7 to 17 nm. Conventionally, a vapor deposition method is used to form a metal thin film. However, it has been found that the following problems occur when a silver thin film is formed as a translucent electrode.

First, when producing a translucent electrode by vapor deposition, nonuniformity of film quality due to impurities may occur. Specifically, since the melting point of silver (Ag) is 960 ° C. or higher, impurities attached to the vapor deposition apparatus, in particular, water (H ₂ O) and oxygen (O ₂ ) are easily deposited on silver atoms, The purity of the deposited silver thin film may decrease locally. Therefore, the film quality is not stable, and the sheet resistance value may increase locally or the light transmittance may decrease.In particular, in a large panel or between a plurality of panels cut out from one large substrate, It may be a cause that stable quality cannot be obtained.

  Second, a high resistance can be generated by forming the silver thin film in an island shape. FIG. 9 shows a cross-sectional view of a silver thin film formed by vapor deposition. As shown in FIG. 9, the silver thin film 601 on the substrate grows inhomogeneously so as to form a coarse crystal (hereinafter referred to as “island”) 610. Such a silver thin film grows inhomogeneously, resulting in a difference in electrical resistance between the island interior and the island exterior. Accordingly, inhomogeneity of electric resistance occurs in the translucent electrode, which may cause variation in luminance of the light emitting panel. Since this phenomenon does not occur when the film thickness is 50 nm or more, it is not necessary to consider when using a silver film as a reflective electrode, but only when using a silver film as a translucent electrode. .

  Third, the deposition method using a line source may deteriorate the uniformity of the film quality with respect to a large substrate. In the vapor deposition method using a line source, vapor deposition is performed while a rod-shaped metal (line source) serving as a vapor deposition source and a substrate serving as a vapor deposition target are opposed to each other and the substrate is conveyed at a constant speed in a direction orthogonal to the vapor deposition source metal. However, in the case of a large substrate, it is necessary to prepare a plurality of line sources, and it becomes difficult to make the film quality uniform.

  In order to deal with these problems, the inventor has an idea of forming a silver thin film by a sputtering method. By using the sputtering method, the above first and third problems can be avoided. However, if the sputtering method is simply used, the second problem described above may still occur. This is because the islanding phenomenon is not caused by the vapor deposition method but is a characteristic of silver. Therefore, the inventors examined sputtering using a target obtained by adding other elements to silver, and found that island formation can be prevented by using a target obtained by adding copper (Cu) to silver. It came to implement | achieve the manufacturing method of the disclosed light emission panel.

<Disclosure>
A manufacturing method of a light-emitting panel according to one embodiment of the present disclosure is a manufacturing method in which a light-emitting panel is formed in the order of an anode, a light-emitting layer, and a cathode above a substrate, and sputtering using a target containing silver as a main component and copper The cathode is formed by a method so as to have optical transparency.
According to this method for manufacturing a light-emitting panel, the uniformity of the cathode as the translucent electrode can be improved. Therefore, both low resistance and high translucency can be achieved. Thereby, the brightness | luminance of a light emission panel, efficiency, and lifetime can be improved.

Further, the formation of the cathode is performed by setting a target so as to extend in one direction and performing sputtering while transporting the substrate along a transport path provided in a direction orthogonal to the one direction. Also good.
Thereby, a cathode having a stable film thickness can be formed in a short time regardless of the area of the substrate.

In addition, the transport speed of the substrate in the transport path may be controlled such that the film thickness of the cathode at the completion of formation is 7 nm or more and 17 nm or less.
Thereby, both the electrical conductivity of the cathode and the transmittance of visible light can be kept high, and a high-performance light-emitting panel can be manufactured.
Further, as the target, a material obtained by adding copper to silver may be used.

Thereby, the composition of the cathode can be stabilized, and the uniformity of the cathode can be maintained high.
Further, as the target, a mixture of silver and copper containing silver as a main component may be used.
Thereby, it is not necessary to produce | generate a target as an alloy, and the light emission panel which concerns on this indication can be manufactured by a simpler method.

The light-emitting panel according to one embodiment of the present disclosure is a light-emitting panel in which an anode, a light-emitting layer, and a cathode are stacked in this order on a substrate, and the cathode is made of a material containing silver as a main component and containing copper. And has optical transparency.
According to this light-emitting panel, the cathode as the translucent electrode has high homogeneity, and high electrical conductivity and translucency, so that there is no luminance unevenness and high efficiency and long life can be realized.

The thickness of the cathode may be 7 nm or more and 17 nm or less.
Thereby, the translucency and electrical conductivity of a cathode can be made to make a balance.
<Embodiment>
1. Schematic Configuration of Light-Emitting Panel As an example of a light-emitting panel that is one embodiment of the present invention, a case where the present invention is applied to an organic EL display panel will be described.

  FIG. 1 is a partially enlarged cross-sectional view illustrating a schematic configuration of a light emitting panel 100 according to an embodiment. The light emitting panel 100 includes a plurality of light emitting elements 1 arranged in a matrix on a substrate 11. One light-emitting element corresponds to one sub-pixel (sub-pixel), and corresponds to one of the emission colors R (red), G (green), and B (blue). One pixel (pixel) is constituted by three sub-pixels (sub-pixels) corresponding to R, G, and B, respectively. That is, one pixel is composed of three light emitting elements 1 including a light emitting element 1 (R) corresponding to R color, a light emitting element 1 (G) corresponding to G color, and a light emitting element 1 (B) corresponding to B color. Become. The light emitting panel 100 is a so-called top emission type color display panel with the upper side of the figure as a display surface.

In addition, (R), (G), and (B) are not attached | subjected when it is not necessary to distinguish a component especially by luminescent color. For example, when the emission colors are not particularly distinguished, they are simply referred to as the light emitting element 1.
The light emitting panel 100 includes a substrate 11, an interlayer insulating layer 12, a lower electrode 13, a hole injection layer 14, a partition wall layer 15, a hole transport layer 16, and a light emitting layer 17 (17 (R), 17 (G), 17 (B )), An electron transport layer 18, an electron injection layer 19, an upper electrode 20, and a sealing layer 21. The substrate 11, the interlayer insulating layer 12, the hole injection layer 14, the electron transport layer 18, the electron injection layer 19, the upper electrode 20, and the sealing layer 21 are formed in common for a plurality of pixels.

Then, each part structure of the light emission panel 100 is demonstrated.
(1) Substrate The substrate 11 includes a base material 111 that is an insulating material and a TFT (Thin Film Transistor) layer 112. In the TFT layer 112, a drive circuit (not shown) is formed for each subpixel. As a material for forming the base material 111, for example, glass is used. Specific examples of the glass material include alkali-free glass, soda glass, non-fluorescent glass, phosphate glass, borate glass, quartz glass, and the like.

1.2 Interlayer Insulating Layer The interlayer insulating layer 12 is formed on the substrate 11. The interlayer insulating layer 12 is made of a resin material, and is for flattening a step on the upper surface of the TFT layer 112. As the resin material on which the interlayer insulating layer 12 is formed, for example, a positive photosensitive material is used. Examples of such photosensitive materials include acrylic resins, polyimide resins, siloxane resins, and phenol resins.

(3) Lower electrode (anode)
The lower electrode 13 is made of a conductive material, and is formed on the interlayer insulating layer 12 for each subpixel. The lower electrode 13 is an anode, and includes a barrier metal layer 13a and a lower electrode layer 13b stacked on the barrier metal layer 13a. The barrier metal layer 13a is made of, for example, a metal or alloy containing a transition metal element such as tungsten (W), molybdenum (Mo), or iron (Fe). In the present embodiment, the barrier metal layer 13a is made of tungsten.

  In addition, since the light emitting panel 100 according to the present embodiment is a top emission type, the lower electrode layer 13b is preferably formed of a conductive material having light reflectivity. Examples of the conductive material having light reflectivity include metals. Specifically, Ag (silver), Al (aluminum), aluminum alloy, Mo (molybdenum), APC (silver, palladium, copper alloy), ARA (silver, rubidium, gold alloy), MoCr (molybdenum and chromium) Alloy), MoW (alloy of molybdenum and tungsten), NiCr (alloy of nickel and chromium), and the like can be used. In the present embodiment, the lower electrode layer 13b is made of a metal material containing aluminum, and more specifically, is made of ACL (an alloy of aluminum, cobalt, and lanthanum).

Note that a layer of a light-transmitting conductive material may be stacked on the lower electrode 13. In this case, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), ZnO (zinc oxide), or the like can be used as the light transmissive conductive material.
Although not shown in this cross-sectional view, a contact hole is formed in the interlayer insulating layer 12 for each sub-pixel. A TFT connection wiring is embedded in the contact hole, and the lower electrode 13 is electrically connected to a drive circuit formed in the TFT layer 112 via the TFT connection wiring.

(4) Hole Injection Layer The hole injection layer 14 has a function of promoting the injection of holes from the lower electrode 13 to the light emitting layer 17. The hole injection layer 14 is made of, for example, a metal oxide and is disposed on the lower electrode 13. The hole injection layer 14 is formed by, for example, a sputtering method. Examples of the metal oxide that is a material for forming the hole injection layer 14 include tungsten oxide (WOx), molybdenum oxide (MoOx), silver (Ag), chromium (Cr), vanadium (V), and nickel (Ni). An oxide such as iridium (Ir) can be used. In the present embodiment, the hole injection layer 14 is provided on the lower electrode 13 and the interlayer insulating layer 12 in common for a plurality of pixels.

(5) Partition Layer The partition layer 15 is formed on the hole injection layer 14 in a state where a part of the upper surface of the hole injection layer 14 is exposed and the peripheral region is covered. A region of the upper surface of the hole injection layer 14 that is not covered with the partition wall layer 15 (hereinafter referred to as “opening”) corresponds to a subpixel. That is, the partition wall layer 15 has an opening 15a provided for each subpixel.

  The partition layer 15 is made of, for example, an insulating organic material (for example, an acrylic resin, a polyimide resin, a novolac resin, a phenol resin, or the like). The partition wall layer 15 functions as a structure for preventing the applied ink from overflowing when the light emitting layer 17 is formed by a coating method, and when the light emitting layer 17 is formed by a vapor deposition method, It functions as a structure for mounting a vapor deposition mask. In this embodiment, the partition layer 15 is made of a resin material, and for example, a positive photosensitive material can be used. Specific examples of such photosensitive materials include acrylic resins, polyimide resins, siloxane resins, and phenol resins.

(6) Hole Transport Layer The hole transport layer 16 has a function of transporting holes injected from the hole injection layer 14 to the light emitting layer 17, and holes are transferred from the hole injection layer 14 to the light emitting layer 17. In order to transport efficiently, it is made of an organic material having a high hole mobility. The hole transport layer 16 is formed by applying an organic material solution and drying. As an organic material for forming the hole transport layer 16, polymer compounds such as polyfluorene and derivatives thereof, or polyarylamine and derivatives thereof can be used.

  The hole transport layer 16 is composed of triazole derivative, oxadiazole derivative, imidazole derivative, polyarylalkane derivative, pyrazoline derivative and pyrazolone derivative, phenylenediamine derivative, arylamine derivative, amino-substituted chalcone derivative, oxazole derivative, styrylanthracene derivative, Fluorenone derivative, hydrazone derivative, stilbene derivative, porphyrin compound, aromatic tertiary amine compound and styrylamine compound, butadiene compound, polystyrene derivative, hydrazone derivative, triphenylmethane derivative, tetraphenylbenzene derivative may be used. . Particularly preferably, a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound may be used. In this case, the hole transport layer 16 is formed by a vacuum evaporation method.

(7) Light-Emitting Layer The light-emitting layer 17 includes an organic light-emitting material, and is formed in the opening 15 a located above the lower electrode 13. The light emitting layer 17 has a function of emitting light of each color of R, G, and B by recombination of holes and electrons. In the light emitting panel 100 according to the present embodiment, the light emitting layer 17 is formed by applying an ink containing an organic light emitting material into the opening 15a by inkjet.

  Examples of the organic light emitting material included in the light emitting layer 17 include an oxinoid compound, a perylene compound, a coumarin compound, an azacoumarin compound, an oxazole compound, an oxadiazole compound, a perinone compound, a pyrrolopyrrole compound, a naphthalene compound, an anthracene compound, a fluorene compound, Fluoranthene compound, tetracene compound, pyrene compound, coronene compound, quinolone compound and azaquinolone compound, pyrazoline derivative and pyrazolone derivative, rhodamine compound, chrysene compound, phenanthrene compound, cyclopentadiene compound, stilbene compound, diphenylquinone compound, styryl compound, butadiene compound, Dicyanomethylenepyran compound, dicyanomethylenethiopyran compound, fluorescein compound, pyrylium Products, thiapyrylium compounds, serenapyrylium compounds, telluropyrylium compounds, aromatic aldadiene compounds, oligophenylene compounds, thioxanthene compounds, cyanine compounds, acridine compounds, metal complexes of 8-hydroxyquinoline compounds, metal complexes of 2-bipyridine compounds, Schiff A fluorescent substance such as a complex of a salt and a group III metal, an oxine metal complex, or a rare earth complex can be used. In addition, a known phosphor such as a metal complex emitting phosphorescence such as tris (2-phenylpyridine) iridium can be used. The light emitting layer 17 is formed using polyfluorene or a derivative thereof, polyphenylene or a derivative thereof, a polymer compound such as polyarylamine or a derivative thereof, or a mixture of the low molecular compound and the polymer compound. Also good.

(8) Electron Transport Layer The electron transport layer 18 is provided on the light emitting layer 17 and the partition wall layer 15 in common for a plurality of pixels, and functions to transport electrons injected from the upper electrode 20 to the light emitting layer 17. Have The electron transport layer 18 is formed using, for example, an oxadiazole derivative (OXD), a triazole derivative (TAZ), a phenanthroline derivative (BCP, Bphen), or the like.

(9) Electron Injection Layer The electron injection layer 19 is provided in common to a plurality of pixels on the electron transport layer 18 and has a function of promoting injection of electrons from the upper electrode 20 to the light emitting layer 17. The electron injection layer 19 includes, for example, a low work function metal such as lithium, barium, calcium, potassium, cesium, sodium, and rubidium, a low work function metal salt such as lithium fluoride, and a low work function metal oxide such as barium oxide. It is formed using etc.

(10) Upper electrode (cathode)
The upper electrode 20 is provided on the electron injection layer 19 in common to a plurality of pixels and is a cathode. The upper electrode 20 is formed by sputtering. The upper electrode 20 is formed of a Cu-added Ag alloy having a thickness of about 7 to 17 nm. By forming the upper electrode 20 with a light-transmitting thickness, light generated in the light emitting layer 17 can be extracted from the upper electrode 20 side.

(11) Sealing Layer On the upper electrode 20, a sealing layer 21 is provided. The sealing layer 21 prevents impurities (water, oxygen) from entering the upper electrode 20, the electron injection layer 19, the electron transport layer 18, the light emitting layer 17, and the like from the opposite side of the substrate 11. It has a function to suppress deterioration of. Since the light emitting panel 100 according to the present embodiment is a top emission type display panel, a light transmissive material such as SiN (silicon nitride) or SiON (silicon oxynitride) is used as the material of the sealing layer 21. .

(12) Others Although not shown in FIG. 1, a color filter or an upper substrate may be placed on the sealing layer 21 and bonded. By providing the upper substrate, it is possible to further protect the upper electrode 20, the electron injection layer 19, the electron transport layer 18, the light emitting layer 17, and the like from impurities.
2. Next, an example of a method for manufacturing the light emitting panel 100 will be described with reference to FIGS. 2 to 4 are partial sectional views schematically showing the manufacturing process of the light emitting panel 100, and FIG. 5 is a schematic process diagram showing the manufacturing process of the light emitting panel 100.

First, as shown to Fig.2 (a), the TFT layer 112 is formed on the base material 111, and the board | substrate 11 is formed (step S1 of FIG. 5).
Next, as shown in FIG. 2B, an interlayer insulating layer 12 is formed on the substrate 11 and baked (step S2 in FIG. 5). In this embodiment, an acrylic resin that is a positive photosensitive material is used as the interlayer insulating layer resin that is a material of the interlayer insulating layer 12. The interlayer insulating layer 12 is formed by applying an interlayer insulating layer solution in which an acrylic resin, which is an interlayer insulating layer resin, is dissolved in an interlayer insulating layer solvent (for example, PGMEA) on the substrate 11, and then baking. Do. Firing is performed at a temperature of 150 ° C. or higher and 210 ° C. or lower for 180 minutes, for example.

  Subsequently, as shown in FIG. 2C, a barrier metal material layer 131 is uniformly formed on the interlayer insulating layer 12 (step S3 in FIG. 5). The barrier metal material layer 131 is made of, for example, a metal or alloy containing a transition metal element such as tungsten (W), molybdenum (Mo), or iron (Fe). As a method for forming the barrier metal material layer 131, for example, a sputtering method can be used. In the sputtering method, for example, a metal or alloy flat plate containing a transition metal element may be used as a target member, and argon gas may be used as an inert gas. In this embodiment, the barrier metal material layer 131 is formed with a film thickness of 40 nm using, for example, tungsten.

  Subsequently, as shown in FIG. 2D, a lower electrode layer 132 is formed on the barrier metal material layer 131. The lower electrode layer 132 is uniformly formed on the interlayer insulating layer 12 by sputtering using a light reflective conductive material (step S4 in FIG. 5). The light-reflective conductive material forming the lower electrode layer 132 is a metal material containing aluminum in this embodiment, and more specifically, is ACL (alloy of aluminum, cobalt, and lanthanum). The thickness of the lower electrode layer 132 is, for example, 50 nm or more and 300 nm or less, and in the present embodiment, it is 200 nm.

In the present embodiment, as shown in FIG. 2D, the lower electrode material layer 130 is composed of the lower electrode layer 132 and the barrier metal material layer 131.
Subsequently, as shown in FIG. 2E, a hole injection material layer 140 is formed on the lower electrode material layer 130 including the lower electrode layer 132 and the barrier metal material layer 131 (step S5 in FIG. 5). In the light emitting panel 100 according to the present embodiment, the hole injection material layer 140 is a layer of tungsten oxide and is formed by a reactive sputtering method.

Then, as shown in FIG. 2 (f), the lower electrode material layer 130 and the hole injection material layer 140 are patterned by etching, so that a plurality of lower electrodes 13 and hole injection layers 14 partitioned for each subpixel are formed. It forms (step S6 of FIG. 5).
Each lower electrode 13 includes a barrier metal layer 13a and a lower electrode layer 13b. The barrier metal layer 13a is formed by patterning the barrier metal material layer 131. The lower electrode layer 13b is formed by patterning the lower electrode layer 132. The hole injection layer 14 is formed by patterning the hole injection material layer 140.

In the present embodiment, the hole injection material layer 140 is patterned by dry etching and the lower electrode material layer 130 is patterned by wet etching, but the patterning method is not particularly limited thereto.
Further, after patterning the lower electrode material layer 130 to form the lower electrode 13, the hole injection layer 14 is formed on the lower electrode 13 and the interlayer insulating layer 12 as a uniform film common to each subpixel. Also good.

  Subsequently, as shown in FIG. 3A, a partition wall layer resin that is a material of the partition wall layer 15 is applied on the hole injection layer 14 and the interlayer insulating layer 12 to form a partition wall material layer 150. For the partition layer resin, for example, a phenol resin, which is a positive photosensitive material, is used. For the partition wall material layer 150, a solution obtained by dissolving a phenol resin, which is a partition wall resin, in a solvent (for example, a mixed solvent of ethyl lactate and GBL) is applied to the hole injection layer 14 and the interlayer insulating layer 12 by a spin coating method or the like. It forms by apply | coating uniformly using. Then, the partition wall layer 15 is formed by performing pattern exposure and development on the partition wall material layer 150 (FIG. 3B, step S7 in FIG. 5), and the partition layer 15 is baked (step S8 in FIG. 5). As a result, an opening 15 a that is a formation region of the light emitting layer 17 is defined. The partition layer 15 is baked, for example, at a temperature of 150 ° C. or higher and 210 ° C. or lower for 60 minutes.

In the step of forming the partition wall layer 15, the surface of the partition wall layer 15 may be further subjected to a surface treatment with a predetermined alkaline solution, water, an organic solvent, or the like, or a plasma treatment may be performed. This is performed for the purpose of adjusting the contact angle of the partition wall layer 15 with respect to the ink (solution) applied to the opening 15a, or for the purpose of imparting water repellency to the surface.
Next, as shown in FIG. 3C, the ink containing the constituent material of the hole transport layer 16 is ejected from the nozzle 4030 of the inkjet head 401 to the opening 15 a defined by the partition wall layer 15. It is applied onto the hole injection layer 14 in 15a and baked (dried) to form the hole transport layer 16 (step S9 in FIG. 5).

Then, as shown in FIG. 3D, ink containing the constituent material of the light emitting layer 17 is ejected from the nozzle 4030 of the ink jet head 401 and applied onto the hole transport layer 16 in the opening 15a and fired ( The light emitting layer 17 is formed by performing (drying) (step S10 in FIG. 5).
Subsequently, as shown in FIG. 4A, a material constituting the electron transport layer 18 is formed on the light emitting layer 17 and the partition wall layer 15 in common for each sub-pixel by vacuum deposition or sputtering. Then, the electron transport layer 18 is formed (step S11 in FIG. 5).

Next, as shown in FIG. 4B, the material constituting the electron injection layer 19 is formed on the electron transport layer 18 by a method such as a vapor deposition method, a spin coat method, or a cast method, and is applied to each subpixel. In common, the electron injection layer 19 is formed (step S12 in FIG. 5).
Then, as shown in FIG. 4C, the upper electrode 20 and the sealing layer 21 are formed on the electron injection layer 19. Specifically, first, the upper electrode 20 is formed by forming a film by sputtering using Cu-added Ag (step S13 in FIG. 5).

Here, a method for forming the upper electrode 20 will be further described.
First, a schematic configuration of the sputtering apparatus 500 will be described with reference to FIG. The sputtering apparatus 500 includes a substrate delivery chamber 510, a film formation chamber 520, and a load lock chamber 530, and performs sputtering by a magnetron sputtering method in the film formation chamber 520. A sputtering gas is introduced into the film formation chamber 520. As the sputtering gas, an inert gas such as Ar (argon) is used. In this embodiment, Ar is used.

  A carrier 521 in the sputtering apparatus 500 is provided with a substrate 522 to be deposited. The substrate 522 is mounted on the carrier 521 by the substrate push-up mechanism 511 in the substrate delivery chamber 510. The carrier 521 on which the substrate 522 is mounted linearly moves on the transfer path 501 at a constant speed from the substrate transfer chamber 510 to the load lock chamber 530 through the film formation chamber 520. In the present embodiment, the moving speed of the carrier 521 is 30 mm / s. Note that the substrate 522 is not heated and is sputtered at room temperature.

  In the film forming chamber 520, a rod-like target 523 is installed that extends in a direction orthogonal to the transport path 501. In the present embodiment, the target 523 is Ag to which Cu is added. A magnet 525 is disposed below the target 523. Note that the target 523 need not be a rod-shaped metal, and may be, for example, a powder. Moreover, the target 523 should just contain silver as a main component, and copper does not need to be added to silver. For example, a mixture obtained by adding a small amount of copper powder to silver powder may be used as the target 523.

The power source 524 applies a voltage to the target 523. In FIG. 6, the power source 524 is an AC power source, but may be a DC power source or a DC / AC hybrid power source.
The inside of the sputtering apparatus 500 is exhausted by the exhaust system 531, and the sputtering gas is introduced into the film formation chamber 520 by the gas supply system 532. When voltage is applied to the target 523 by the power source 524, plasma of sputtering gas is generated and the surface of the target 523 is sputtered. Then, a film is formed by depositing the atoms of the sputtered target 523 on the substrate 522.

In addition, the gas pressure of Ar which is sputtering gas is 0.6 Pa, for example, and the flow rate is 100 sccm.
Subsequently, the sealing layer 21 is formed on the upper electrode 20 using SiN as a material by sputtering, CVD (Chemical Vapor Deposition), or the like (step S14 in FIG. 5).

The light emitting panel 100 is completed through the above steps. Thus, in the light emitting panel 100 according to this embodiment, when the upper electrode 20 is formed, silver (Ag) to which copper (Cu) is added is used as a target.
A color filter or an upper substrate may be placed on the sealing layer 21 and bonded.
3. Regarding the characteristics of the upper electrode The inventors conducted an evaluation test on the surface state, electrical resistance, and light transmittance of the upper electrode. There are four types of samples used for the evaluation test. The sample A is a sample in which the upper electrode 20 is formed with a film thickness of 15 nm on IZO (Indium Zinc Oxide) using silver (Ag) to which copper (Cu) is added as a target. Sample B is a sample in which the upper electrode 20 is formed with a film thickness of 15 nm on IZO as in sample A, using pure silver (Ag) as a target. The sample C is a sample in which the upper electrode 20 is formed with a film thickness of 15 nm on the organic functional layer by using silver (Ag) to which copper (Cu) is added as a target. Sample D is a sample in which the upper electrode 20 is formed on the organic functional layer with a film thickness of 15 nm using pure silver (Ag) as a target.
(1) Surface State FIGS. 7A to 7D show electron micrographs obtained by imaging the surface of the upper electrode 20 in each sample. As shown in FIGS. 7B and 7D, in the upper electrode 20 using pure silver as a target, islands 301 of about 1 to several μm are formed and voids (voids) 302 are generated. On the other hand, as shown in FIGS. 7 (a) and 7 (c), in the upper electrode 20 targeting silver added with copper, neither islands nor voids are found, and the film quality is uniform. This can be caused by the following reasons. Possible reasons for islanding and void formation in pure silver thin films are that when sputtered silver atoms are deposited on the substrate, they are more likely to settle on silver atoms than on other atoms. It is. That is, since silver atoms are easily fixed on silver already deposited on the substrate, silver crystals are coarsened and islands are generated. On the other hand, silver atoms are fixed on the surface of IZO or the organic functional layer. It is difficult to form voids. On the other hand, when copper is added, the film quality becomes uniform because the sputtered silver atoms are more likely to be fixed on the copper atoms than on the silver atoms. If the locations where silver atoms are likely to settle are in the order of copper atoms, silver atoms, and other locations in that order, the location where the copper atoms have settled becomes the center of thin film growth, making it difficult for voids to form and This is because the phenomenon of excessive crystal growth and island formation is suppressed.

(2) Sheet resistance value FIG.7 (e) shows the sheet resistance value of each sample. As shown in FIG. 7E, in the samples A and C in which the upper electrode 20 contains copper, the sheet resistance value is increased by about 60% compared to the samples B and D in which the upper electrode 20 is pure silver. Yes. However, Sample A and Sample C also have a sufficiently small sheet resistance value with respect to ITO and IZO having the same film thickness, and have higher conductivity than the upper electrode formed of a metal oxide.

(3) Light Transmittance FIGS. 8A and 8B show the light transmittance of each sample. As shown in FIG. 8A, in the upper electrode 20 formed on the IZO, the light transmittance of the sample A containing copper is substantially the same as the light transmittance of the sample B not containing the same. On the other hand, as shown in FIG. 8B, in the upper electrode 20 formed on the organic functional layer, the wavelength of the sample C containing copper is 500 nm or more (green to red, and In the case of infrared light, the light transmittance is reduced by several percent. However, the light transmittance of sample C is slightly lower than that of sample D, and the light transmittance of visible light is sufficiently high.

(4) Summary As described above, in the upper electrode 20 made of a silver alloy containing copper, the visible light transmittance is sufficiently high and the sheet resistance value is sufficiently small. Furthermore, since the film quality is uniform, the film quality of the cathode as the translucent electrode can be stabilized regardless of the substrate size when forming the cathode.

4). Overall Configuration of Organic EL Display Device FIG. 10 is a schematic block diagram showing a configuration of an organic EL display device 1000 including the light emitting panel 100. As shown in FIG. 10, the organic EL display device 1000 includes a light emitting panel 100 and a drive control unit 200 connected thereto. The drive control unit 200 includes four drive circuits 210 to 240 and a control circuit 250.

In the actual organic EL display device 1000, the arrangement of the drive control unit 200 with respect to the light emitting panel 100 is not limited to this.
4). In the above embodiment, the case where the present invention is applied to an organic EL display device as an example of a light emitting panel according to the present disclosure has been described. However, the present invention is not limited thereto. The light emitting panel according to the present disclosure may be a light emitting panel using an inorganic light emitting material.

Moreover, it is not limited to a display device, but may be a panel type lighting device such as an organic EL lighting device.
As described above, the organic light emitting panel and the display device according to the present disclosure have been described based on the embodiments and the modifications. However, the present invention is not limited to the above embodiments and the modifications. By arbitrarily combining the components and functions in the embodiments and modifications without departing from the gist of the present invention, and forms obtained by making various modifications conceivable by those skilled in the art with respect to the above-described embodiments and modifications. Implemented forms are also included in the present invention.

  The present invention provides a light emitting panel having a configuration in which light emitted from a light emitting layer is configured to extract light to the outside when an electrode layer disposed on one side of the light emitting layer has light transmittance. This is useful for manufacturing a light-emitting panel in which the internal variation is suppressed.

11 Substrate 13 Lower electrode 17 Light emitting layer 20 Upper electrode 100 Light emitting panel

Claims (7)

A manufacturing method for forming a light emitting panel in the order of an anode, a light emitting layer, and a cathode above a substrate,
A method for manufacturing a light-emitting panel, wherein the cathode is formed so as to have light transmittance by a sputtering method using a target containing silver as a main component and copper. The formation of the cathode is performed by setting a target so as to extend in one direction and performing sputtering while transporting the substrate along a transport path provided in a direction orthogonal to the one direction. The manufacturing method of the light emission panel of description. The method for manufacturing a light-emitting panel according to claim 2, wherein the transport speed of the substrate in the transport path is controlled such that the film thickness of the cathode at the completion of the creation is 7 nm or more and 17 nm or less. The manufacturing method of the light emission panel of any one of Claim 1 to 3 which uses the material which added copper to silver for the said target. The manufacturing method of the light emission panel of any one of Claim 1 to 3 which uses the mixture of silver and copper which has silver as a main component as said target. A light emitting panel in which an anode, a light emitting layer, and a cathode are laminated in this order above a substrate,
The cathode is a light-emitting panel made of a material containing silver as a main component and containing copper and having light transmittance. The light emitting panel according to claim 6, wherein the cathode has a thickness of 7 nm to 17 nm.