JP2013110014A - Organic el element manufacturing method and organic el display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an organic EL element having an excellent quality, which suppresses increase in a contact resistance value at a contact hole caused by calcination.SOLUTION: An organic EL element manufacturing method comprises: a first step of preparing a substrate on which a TFT layer including a wiring part of metal is formed on a top face; a second step of laminating a layer of an insulation film material on the TFT layer; a third step of forming contact holes in the insulation film material layer so as to expose a part of the wiring part; a fourth step of heating and burning the insulation film material layer in an oxygen containing atmosphere to form an insulation film layer; a fifth step of dissolving a metal oxide formed by oxidation of metal on a surface of the wiring part in the fourth step in an etchant and removing the metal oxide; and a sixth step of forming pixel electrodes at the contact holes so as to be electrically connected to the part of the wiring part, and forming an organic luminescent layer above the pixel electrodes, and forming counter electrodes above the organic luminescent layer.

Description

  The present invention relates to a method for manufacturing an organic EL element and an organic EL display panel.

In recent years, organic EL display panels in which organic EL elements are arranged on a substrate as a display device are becoming widespread. The organic EL display panel has characteristics such as high visibility because it uses an organic EL element that performs self-emission, and excellent impact resistance because it is a complete solid element.
The organic EL element is a current-driven light-emitting element, and is configured by laminating an organic light-emitting layer or the like that performs an electroluminescence phenomenon due to carrier recombination between an anode and a cathode electrode pair. Insulating films are used for various purposes such as separating the stacked layers to ensure electrical insulation between the layers, surface protection, and impurity diffusion prevention.

In addition, when it is necessary to make electrical connection between the electrodes disposed in the layers separated by the insulating film, a part of the insulating film is removed by etching or the like to expose a part of the electrode surface. A contact hole is formed in the contact hole, and a conductive layer (electrode layer) is formed in the contact hole for electrical connection.
As the insulating film, for example, an insulating film obtained by baking (heating treatment, also referred to as baking) a resin containing a siloxane polymer and causing the solvent to volatilize and the low-molecular component to undergo a crosslinking reaction is known. (For example, patent document 1).

JP 2006-128638 A

  When the insulating film is baked, the low molecular crosslinking reaction proceeds and becomes hard, so that the insulating film can be easily etched before baking. Thus, there are cases where firing is performed after the contact holes are formed. However, in that case, the exposed surface of the metal electrode exposed through the contact hole reacts with oxygen in the air by heating during firing to form an oxide film. Then, when the electrode layer is formed in the contact hole after firing, the electrode layer is connected to the oxide film. As a result, the contact resistance value (connection resistance value) increases, the desired luminance is not supplied to the organic light emitting layer, and uneven brightness occurs in the organic EL display panel, or the amount of heat generation increases to promote deterioration. May cause problems.

  The present invention has been made in view of the above problems, and in the case of performing firing after forming a contact hole, a method for producing an organic EL element having good quality in which an increase in contact resistance value in the contact hole is suppressed is provided. The purpose is to provide.

  An organic EL element which is one embodiment of the present invention includes a first step of preparing a substrate having a TFT layer including a metal wiring portion formed on an upper surface thereof, and a layer of an insulating film material on the TFT layer. A second step of laminating, a third step of forming a contact hole in the insulating film material layer so that a part of the wiring portion is exposed, and a layer of the insulating film material comprising oxygen. A fourth step in which an insulating film layer is formed by heating and baking in an atmosphere, and a metal oxide formed by oxidizing the metal on the surface of the wiring portion in the fourth step is dissolved and removed in an etchant. In a fifth step, a pixel electrode is formed so as to be electrically connected to a part of the wiring portion in the contact hole, an organic light emitting layer is formed above the pixel electrode, and above the organic light emitting layer A sixth step of forming a counter electrode. The features.

  In the method for manufacturing an organic EL element according to one embodiment of the present invention, the metal oxide formed in the fourth step is removed by wet etching in the fifth step, thereby reducing the contact resistance value in the contact portion. Can be made. As a result, an organic EL device having good quality can be provided.

It is a schematic block diagram which shows the structure of the display apparatus which concerns on embodiment of this invention. It is a schematic cross section which shows the structure of the display panel in a display apparatus. It is a schematic cross section which shows a part of manufacturing process of a display panel. It is a schematic cross section which shows a part of manufacturing process of a display panel. It is a schematic cross section which shows a part of manufacturing process of a display panel. It is a schematic process diagram which shows the manufacturing process of a display panel. It is a graph which shows the contact resistance value in a contact hole, Comprising: (a) is a graph which shows the contact resistance value at the time of using high-density molybdenum for a feeding electrode, (b) is low-density molybdenum for a feeding electrode. It is a graph which shows the contact resistance value at the time of using. It is a table | surface which shows the yield rate about the contact resistance value in the contact hole of the display panel which concerns on embodiment, and the contact resistance value of a comparative example. (A) is a graph which shows the contact angle of the water in the contact hole with and without the hydrophilization treatment, and (b) the contact with and without the hydrophilization treatment. It is a graph which shows the contact resistance value in a hole.

<< Outline of One Embodiment of the Present Invention >>
The manufacturing method of the organic EL element which concerns on 1 aspect of this invention is characterized by performing the following process. A first step of preparing a substrate having a TFT layer including a wiring portion made of metal formed on an upper surface; a second step of laminating a layer of a material for an insulating film on the TFT layer; and A third step of forming a contact hole in the insulating film material layer so that a part of the insulating film material is exposed, and an insulating film layer is formed by heating and baking the insulating film material layer in an oxygen-containing atmosphere. A fourth step of removing the metal oxide formed by oxidizing the metal on the surface of the wiring part in the fourth step by dissolving in an etchant; and the wiring in the contact hole. Forming a pixel electrode so as to be electrically connected to a part of the portion, forming an organic light emitting layer above the pixel electrode, and forming a counter electrode above the organic light emitting layer;

Further, in a specific aspect of the method for manufacturing an organic EL element according to one embodiment of the present invention, in the fifth step, the surface of the contact hole is made hydrophilic before the metal oxide is dissolved and removed in an etchant. It is characterized in that it is processed.
In a specific aspect of the method for manufacturing an organic EL element according to one embodiment of the present invention, the hydrophilization treatment is performed by ozone cleaning or ultraviolet irradiation.

Moreover, in a specific aspect of the method for manufacturing an organic EL element according to one embodiment of the present invention, the hydrophilization treatment is performed with hydrogen peroxide water or ozone water.
In a specific aspect of the method for manufacturing an organic EL element according to one embodiment of the present invention, the metal forming the wiring portion is titanium, molybdenum, or tungsten.
Moreover, in a specific aspect of the method for manufacturing an organic EL element according to one embodiment of the present invention, the etchant is an acidic liquid containing oxalic acid or an alkaline liquid containing ammonia.

In a specific aspect of the method for manufacturing an organic EL element according to one embodiment of the present invention, the pixel electrode is formed of aluminum or an aluminum alloy.
The organic EL display panel according to one embodiment of the present invention can include an organic EL element according to each of the above embodiments.
Hereinafter, a specific example is shown and a structure, an effect | action, and an effect are demonstrated.

The embodiment used in the following description is an example used to explain the configuration, operation, and effect of the present invention in an easy-to-understand manner, and the present invention is not limited to the following form other than its essential part. It is not something to receive.
<< Embodiment >>
[1. Overall configuration of display device]
Below, the structure of the display apparatus 1 containing the organic EL element which concerns on embodiment is demonstrated using FIG.

As shown in FIG. 1, the display device 1 includes a display panel 100 and a drive control unit 20 connected thereto. The display panel 100 is a panel using an electroluminescence phenomenon of an organic material, and a plurality of organic EL elements are arranged in a matrix, for example. The drive control unit 20 includes four drive circuits 21 to 24 and a control circuit 25.
In the actual display device 1, the arrangement of the drive control unit 20 with respect to the display panel 100 is not limited to this.

[2. Display panel configuration]
The configuration of the display panel 100 will be described with reference to FIG.
FIG. 2 is a partial cross-sectional view of the configuration of the display panel 100. The display panel 100 is a so-called top emission type in which the upper side of FIG.
As shown in FIG. 2, the display panel 100 is formed using a substrate 101 as a base. On the substrate 101, a TFT (thin film transistor) layer 102 and a feeding electrode (wiring portion) 103 are formed, and an interlayer insulating film 104 is laminated so as to cover it.

A pixel electrode 106 is formed on the interlayer insulating film 104 which is an insulating layer, and a hole injection layer 109 is stacked so as to cover the pixel electrode 106.
On the hole injection layer 109, a partition layer 107 is provided in which a plurality of openings 117 (see FIG. 4), which are regions where the organic light emitting layer 111 is formed, are formed. A hole transport layer 110 and an organic light emitting layer 111 are sequentially stacked in the opening 117.

An electron transport layer 112, an electron injection layer 113, a counter electrode 114, and a sealing layer 118 are sequentially stacked on the organic light emitting layer 111 and the partition wall layer 107.
<Substrate, TFT layer, feeding electrode>
A substrate 101 is a rear substrate in the display panel 100, and a TFT layer 102 including a TFT (thin film transistor) for driving the display panel 100 by an active matrix method is formed on the surface thereof. The TFT layer 102 includes a power supply electrode 103 which is a wiring portion for supplying power from the outside to each TFT. However, in this embodiment, another reference numeral is used for easy understanding. A description will be given. Further, in the present embodiment, the power supply electrode 103 is formed using molybdenum (Mo).

<Interlayer insulation film>
The interlayer insulating film 104 is provided in order to adjust the level difference generated by the TFT layer 102 and the power supply electrode 103 to be flat, and is made of an organic material having excellent insulating properties.
<Contact hole>
The contact hole (contact part) 105 is provided to electrically connect the power supply electrode 103 and the pixel electrode 106, and is formed from the front surface to the back surface of the interlayer insulating film 104. The contact holes 105 are formed so as to be positioned between the openings 117 (see FIG. 4) arranged in the column direction, and are configured to be covered with the partition wall layer 107. When the contact hole 105 is not covered with the partition wall layer 107, the presence of the contact hole 105 causes the organic light emitting layer 111 not to be a flat layer and causes uneven light emission. In order to avoid this, the above configuration is adopted.

<Pixel electrode>
The pixel electrode 106 is an anode and is formed for each organic light emitting layer 111 formed in the opening 117. Since the display panel 100 is a top emission type, a light reflective material is selected as the material of the pixel electrode 106. The light reflective material is, for example, a laminated film of a metal film made of a metal mainly composed of aluminum (Al) and a nickel (Ni) film.

<Hole injection layer>
The hole injection layer 109 is provided for the purpose of promoting the injection of holes from the pixel electrode 106 to the organic light emitting layer 111.
<Partition wall layer>
When the organic light emitting layer 111 is formed, the partition layer 107 is mixed with an organic light emitting layer material corresponding to each color of red (R), green (G), and blue (B) and an ink (liquid) containing a solvent. It serves to prevent this.

The partition layer 107 provided so as to cover the contact hole 105 has a trapezoidal cross section along the XZ plane or the YZ plane as a whole, but the position corresponding to the contact hole 105 Then, the shape of the partition wall layer material is contracted and depressed.
<Hole transport layer>
The hole transport layer 110 has a function of transporting holes injected from the pixel electrode 106 to the organic light emitting layer 111.

<Organic light emitting layer>
The organic light emitting layer 111 is a portion that emits light by recombination of carriers (holes and electrons), and is configured to include an organic material corresponding to any of R, G, and B colors. Is formed. In a display panel using organic EL elements, the organic EL elements corresponding to R, G, and B colors are subpixels, and the combination of the three subpixels R, G, and B is one pixel (one pixel). It corresponds to.

In addition, all the organic light emitting layers 111 formed in each opening part 117 (refer FIG. 4) can also be made into the organic light emitting layer of the same color.
<Electron transport layer>
The electron transport layer 112 has a function of transporting electrons injected from the counter electrode 114 to the organic light emitting layer 111.

<Electron injection layer>
The electron injection layer 113 has a function of promoting the injection of electrons from the counter electrode 114 to the organic light emitting layer 111.
<Counter electrode>
The counter electrode 114 is a cathode. Since the display panel 100 is a top emission type, a light transmissive material is selected as the material of the counter electrode 114.

<Sealing layer>
A sealing layer is provided on the counter electrode 114 for the purpose of preventing the organic light emitting layer 111 from being deteriorated by contact with moisture or air. Since the display panel 100 is a top emission type, a light transmissive material such as SiN (silicon nitride) or SiON (silicon oxynitride) is selected as the material of the sealing layer.

<Others>
Although not shown in FIG. 2, a color filter or an upper substrate may be placed on the sealing layer 118 and bonded. By placing and bonding the upper substrate, the organic layers (the hole transport layer 110, the organic light emitting layer 111, and the electron transport layer 112) are protected from moisture and air.
<Material of each layer>
Next, the material of each layer demonstrated above is illustrated. Needless to say, each layer can be formed using materials other than those described below.

Substrate 101: alkali-free glass, soda glass, non-fluorescent glass, phosphate glass, borate glass, quartz, acrylic resin, styrene resin, polycarbonate resin, epoxy resin, polyethylene, polyester, silicone resin, alumina, etc. Interlayer insulating film 104: polyimide resin, acrylic resin Pixel electrode 106: Ag (silver), Al (aluminum), an alloy of silver, palladium and copper, an alloy of silver, rubidium and gold, MoCr ( Molybdenum and chromium alloy), NiCr (nickel and chromium alloy)
Partition layer 107: acrylic resin, polyimide resin, novolak type phenol resin Organic light emitting layer 111: oxinoid compound, perylene compound, coumarin compound, azacoumarin compound, oxazole compound, oxadiazole compound, perinone compound, pyrrolopyrrole compound, naphthalene compound , Anthracene compound, 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 Product, fluorescein compound, pyrylium compound, thiapyrylium compound, serenapyrylium compound, telluropyrylium compound, aromatic ardadiene compound, oligophenylene compound, thioxanthene compound, cyanine compound, acridine compound, metal complex of 8-hydroxyquinoline compound, 2-bipyridine Fluorescent substances such as compound metal complexes, Schiff salts and group III metal complexes, oxine metal complexes, rare earth complexes (all described in JP-A-5-163488)
Hole injection layer 109: Metal oxide such as MoOx (molybdenum oxide), WOx (tungsten oxide) or MoxWyOz (molybdenum-tungsten oxide), metal nitride or metal oxynitride Hole transport layer 110: triazole derivative, oxa Diazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, polyphylline compounds, Aromatic tertiary amine compounds, styrylamine compounds, butadiene compounds, polystyrene derivatives, hydrazone derivatives, triphenylmethane derivatives, tetraphenylbenzine derivatives Conductor (all described in JP-A-5-163488)
Electron transport layer 112: barium, phthalocyanine, lithium fluoride Electron injection layer 113: nitro-substituted fluorenone derivative, thiopyrandioxide derivative, diphequinone derivative, perylenetetracarboxyl derivative, anthraquinodimethane derivative, fluorenylidenemethane derivative, anthrone derivative , Oxadiazole derivatives, perinone derivatives, quinoline complex derivatives (all described in JP-A-5-163488)
Counter electrode 114: ITO (indium tin oxide), IZO (indium zinc oxide)
The configuration of the display panel 100 has been described above. Next, a method for manufacturing the display panel 100 is illustrated.

[3. Manufacturing method of display panel]
Here, the manufacturing method of the display panel 100 according to the embodiment will be described with reference to FIGS. 3 to 5 are cross-sectional views schematically illustrating the manufacturing process of the display panel 100, and FIG. 6 is a schematic process diagram illustrating the manufacturing process of the display panel 100.
First, as shown in FIG. 3A, a substrate 101 on which a TFT layer 102 and a feeding electrode 103 are formed is prepared (step S1 in FIG. 6).

Thereafter, as shown in FIG. 3B, an insulating organic material such as polyimide resin is applied on the TFT layer 102 and the power supply electrode 103 on the basis of the photoresist method, and this is baked to obtain a thickness of about A 4 μm interlayer insulating film 104 is formed (step S2 in FIG. 6).
Subsequently, as shown in FIG. 3C, contact holes 105 are formed at positions corresponding to positions between the openings 117 (regions where the openings 117 are to be formed) in the X-axis direction (see FIG. 6). Step S3)).

Of course, the method of forming the contact hole 105 is not limited to this. For example, the interlayer insulating film 104 and the contact hole 105 can be formed at the same time by performing a photoresist method using a desired pattern mask.
After the contact hole 105 is formed, the interlayer insulating film 104 is baked (step S4 in FIG. 6). As shown in FIG. 3D, the surface of the power supply electrode 103 exposed in the contact hole 105 is oxidized. A film 103a is formed. In this embodiment, the power supply electrode 103 is formed using Mo, and the oxide film 103a is molybdenum oxide (MoOx). In this embodiment, the interlayer insulating film 104 is baked (step S4 in FIG. 6) in the air (atmosphere containing oxygen).

Here, as shown in FIG. 3D, the surface of the contact hole 105 is subjected to ozone cleaning with UV ozone (step S5 in FIG. 6).
Thereafter, as shown in FIG. 3E, wet etching is performed to remove the oxide film 103a (step S6 in FIG. 6). In this embodiment mode, wet etching is performed using oxalic acid as an etchant (developer). Then, as shown in FIG. 4A, the oxide film 103 a of the power supply electrode 103 is removed in the contact hole 105.

  Here, by performing ozone cleaning prior to wet etching as described above, first, the surface of the portion corresponding to the inner wall surface of the concave portion of the contact hole 105 of the interlayer insulating film 104 is hydrophilized to improve wettability. In the subsequent wet etching process, the etchant easily enters the concave portion of the contact hole 105. As a result, the etchant can sufficiently reach the oxide film 103a located at the bottom of the concave portion of the contact hole 105, and the oxide film 103a can be sufficiently removed.

Then, as shown in FIG. 4B, the pixel electrode 106 made of a metal material having a thickness of about 150 [nm] is electrically connected to the power supply electrode 103 based on the vacuum deposition method or the sputtering method for each subpixel. It forms (step S7 of FIG. 6).
Then, as shown in FIG. 4C, the hole injection layer 109 is formed based on the reactive sputtering method (step S8 in FIG. 6).

  Next, as shown in FIG. 4D, the partition layer 107 is formed based on a photolithography method. First, as the partition layer material, a pasty partition layer material containing a photosensitive resist is prepared. This partition wall layer material is uniformly coated on the hole injection layer 109 by using a spin coat method or the like. On this, a mask formed in a pattern corresponding to the opening 117 is arranged and exposed to form a partition wall layer pattern. Thereafter, the excess partition wall layer material is washed with an aqueous or non-aqueous etchant and baked. Thereby, patterning of the partition wall layer material is completed. Thus, the opening 117 serving as the organic light emitting layer forming region is defined, and the partition wall layer 107 having at least a water-repellent surface is completed (step S9 in FIG. 6). In this specification, “patterning” refers to etching into a desired shape.

In the step of forming the partition layer 107, the surface of the partition layer 107 is further subjected to a predetermined surface in order to adjust the contact angle of the partition layer 107 with respect to the ink applied to the opening 117 or to impart water repellency to the surface. Surface treatment may be performed with an alkaline solution, water, an organic solvent, or the like, or plasma treatment may be performed.
Next, as shown in FIG. 4 (e), the hole transport layer 110 is coated with an ink containing the constituent material of the hole transport layer 110 and dried on the opening 117 defined by the partition wall layer 107, and then dried. 110 is formed (step S10 in FIG. 6).

Similarly, as shown in FIG. 5A, the organic light emitting layer 111 is formed by applying and drying ink containing the constituent material of the organic light emitting layer 111 (step S11 in FIG. 6).
Subsequently, as shown in FIG. 5B, a material constituting the electron transport layer 112 is formed on the surface of the organic light emitting layer 111 based on a vacuum deposition method, thereby forming the electron transport layer 112 (FIG. 6). Step S12). Then, a material for forming the electron injection layer 113 is formed on the electron transport layer 112 by a method such as an evaporation method, a spin coat method, or a cast method, so that the electron injection layer 113 is formed. (Step S13 in FIG. 6)
Next, as shown in FIG. 5C, a counter electrode 114 is formed using a material such as ITO or IZO by vacuum deposition, sputtering, or the like (step S14 in FIG. 6). Then, a light transmissive material such as SiN or SiON is formed on the counter electrode 114 by sputtering, CVD, or the like, thereby forming the sealing layer 118 (step S15 in FIG. 6).

The display panel 100 is completed through the above steps. As described above, a color filter or an upper substrate may be placed on the sealing layer 118 and bonded.
[4. Contact resistance reduction effect due to oxide film removal and ozone cleaning]
FIG. 7 is a graph showing the measurement results of contact resistance values when the ozone cleaning process and the oxide film removal process by wet etching are performed. FIG. 7A is a graph in which the measurement results of a test body using high-density molybdenum (Metal 1) for the power supply electrode 103 are plotted, and FIG. 7B is a graph illustrating low-density molybdenum (Metal 2) for the power supply electrode 103. It is the graph which plotted the measurement result of the used specimen. FIG. 8 is a table showing the non-defective rate in the contact resistance value measurement results shown in FIG.

Metal1 and Metal2 are both molybdenum, but the film forming conditions are different. This Kodewa, the term "high density" and "low density", Thornton model (e.g., Hiroshi Ichimura, Masaru Ikenaga al, "Fundamentals and Applications of Thin Films by Plasma Process", Nikkan Kogyo Shimbun the (2005) Reference).
In addition, in both figures, as a comparative example, contact is also made for a test body that has been subjected to oxide film removal treatment by wet etching without performing ozone cleaning, and a test body that has not been wet etched (which has not been subjected to ozone cleaning). The resistance value is measured and these measurement results are also displayed. In both figures, “wet etching + hydrophilization treatment” represents a specimen that was subjected to ozone cleaning treatment and oxide film removal processing by wet etching, and “with wet etching” represents oxide film removal by wet etching without ozone cleaning. The test body which processed was represented, and "no wet etching" represents the test body which did not perform wet etching.

In this measurement test, the reference contact resistance value for discriminating between good and defective products is, for example, 1 [kΩ]. In FIG. 8, a test specimen having a contact resistance value of 1 [kΩ] or less is regarded as a good product. The result of determining and determining a test body larger than 1 [kΩ] as a defective product is shown.
In this test, 12 test specimens subjected to wet etching and 29 test specimens not subjected to wet etching were prepared and contact resistance values were measured.

In this test, contact resistance was measured by a four-terminal resistance measurement method using a semiconductor device analyzer B1500A manufactured by Agilent.
(4-1. Reduction effect of contact resistance value by removing oxide film)
As shown in FIGS. 7 (a), 7 (b) and FIG. 8, when wet etching was not performed (no wet etching), both the test body using Metal1 and the test body using Metal2 were all used. The contact resistance value was larger than 1 [kΩ]. That is, the non-defective rate was 0% for both the test body using Metal1 and the test body using Metal2.

On the other hand, when wet etching is performed (with wet etching), the test resistance using Metal 1 has a contact resistance value of 1 [kΩ] or less in some of the test specimens (non-defective product rate 18%), and Metal 2 is used. In all the test specimens, the contact resistance value was 1 [kΩ] or less in all the specimens (non-defective product rate: 100%).
As can be seen from the above results, the contact resistance value can be lowered by removing the oxide film 103a by performing wet etching (without performing ozone cleaning). In particular, when low density molybdenum (Metal 2) is used for the feeding electrode, the effect is remarkable.

(4-2. Contact resistance reduction effect by ozone cleaning and oxide film removal]
In the test body using Metal 2, when the wet etching was performed, the yield rate was greatly improved from 0% to 100%. However, in the specimen using Metal 1, the yield rate was only 17% even when wet etching was performed.
However, when ozone cleaning is performed and wet etching is performed, the contact resistance value is 1 [kΩ] or less in all the test specimens in both the test specimen using Metal2 and the specimen using Metal1. (Good product rate 100%).

From the above results, even in the test body using Metal1, the etchant sufficiently reaches the bottom of the concave portion of the contact hole by removing the oxide film sufficiently by performing the hydrophilic treatment by ozone cleaning before performing wet etching. It can be seen that the contact resistance value can be reduced.
Here, in order to verify the effect of the hydrophilization treatment by the ozone cleaning, the contact angle of water and the contact resistance value were measured with and without the UV ozone treatment.

  FIG. 9A shows a case where water is applied to a portion of the interlayer insulating film 104 corresponding to the inner wall of the concave portion of the contact hole 105 for each of the five test specimens, with and without the hydrophilic treatment with UV ozone. It is a graph which shows the result of having measured the contact angle of. About the hydrophilization process by UV ozone, the hydrophilization process was performed by three types of methods, excimer UV irradiation, UV ozone processing, and AP plasma irradiation. FIG.9 (b) is a graph which shows the measurement result which measured the contact resistance value about each test body of Fig.9 (a). The contact resistance value was measured by the same method as that for the specimen shown in FIGS.

In the graphs shown in FIGS. 9A and 9B, the test specimen that was not subjected to hydrophilization treatment (without hydrophilization treatment) was the same as the test specimen “with wet etching” in FIG. 7A. It is.
The water contact angle was measured by dropping water onto the test specimen and measuring the angle formed by the test specimen and the droplet end with a contact angle measuring device.

As shown in FIG. 9 (a), the water contact angle of the test body that was not subjected to hydrophilic treatment with UV ozone was approximately 60 °, whereas the test body that was subjected to hydrophilic treatment with UV ozone was In either case, the contact angle of water is reduced to about 10 °, indicating that the wettability is improved.
As shown in FIG. 9 (b), some of the test specimens that were not subjected to the hydrophilic treatment with UV ozone had a contact resistance value of 1 [kΩ] or less, but most of them were larger than 1 [kΩ]. On the other hand, all of the test bodies subjected to the hydrophilization treatment with UV ozone had a contact resistance value of 1 [kΩ] or less and a non-defective product rate of 100%.

  As can be seen from the above results, the wettability of the concave wall surface of the contact hole is improved by performing the hydrophilic treatment by UV ozone cleaning prior to the wet etching, and the etchant enters the concave portion during the wet etching. It becomes easy. The etchant can sufficiently reach the oxide film located at the bottom of the contact hole recess, and the oxide film is sufficiently removed. As a result, it can be seen that the contact resistance value can be reduced and the yield rate can be improved. In other words, since the oxide film remains without being sufficiently removed, it is possible to suppress a decrease in the yield rate due to the contact resistance value becoming high and becoming a defective product.

  Here, as shown in FIG. 7 and FIG. 8, in the case of the specimen using Metal2, the effect of reducing the contact resistance value was obtained sufficiently only by wet etching without performing ozone cleaning. In the case of the test body using Metal1, the following factors can be considered that the contact resistance value reduction effect was not sufficiently obtained by performing only wet etching without performing ozone cleaning. . Metal2 has a low density of molybdenum, so it can be removed relatively easily even with a small amount of etchant, whereas Metal1 has a high density of molybdenum, so it is difficult to remove by etchant, and reaches the bottom of the concave portion of the contact hole. It is considered that if the etchant does not reach sufficiently, the oxide film remains without being sufficiently removed.

[Modification]
As described above, the present invention has been described based on the embodiment. However, the present invention is not limited to the above-described embodiment, and the following modifications can be implemented.
(1) In the above embodiment, oxalic acid is used as the etchant in the wet etching in step S6 in FIG. 6, but this is not restrictive. For example, tetramethylammonium hydroxide (TMAH: Tetramethyl Ammonium Hydroxide) may be used as the etchant.

(2) In the above embodiment, the example in which molybdenum (Mo) is used for the power supply electrode 103 has been described, but the present invention is not limited thereto. For example, the power supply electrode 103 includes molybdenum tungsten (MoW).
(3) Further, titanium (Ti) may be used for the feeding electrode 103. When MoW is used for the feeding electrode 103, the oxide film 103a is molybdenum tungsten oxide (MoWOx), and when Ti is used for the feeding electrode 103, the oxide film 103a is made of titanium monoxide (TiO). Become. When MoW is used for the feed electrode 103, either oxalic acid or TMAH may be used for the etchant. However, when Ti is used for the feed electrode 103, oxalic acid is used for the etchant. Good. Incidentally, when Mo is used for the feeding electrode as in the embodiment, either oxalic acid or TMAH may be used for the etchant.

(4) In the above embodiment, the hydrophilic treatment is performed by performing ozone cleaning with UV ozone in step S5 of FIG. 6, but the present invention is not limited to this. For example, the hydrophilization treatment may be performed using hydrogen peroxide water (H ₂ O ₂ ).
(5) Furthermore, you may hydrophilize using ozone water.
(6) FIG. 2 shows a configuration in which each layer of the TFT layer 102 to the sealing layer 118 is stacked on the substrate 101. In the present invention, any one of the layers may be omitted, or another layer such as a transparent conductive layer may be further included.

  The method for producing the organic EL element of the present invention includes, for example, an organic EL display panel and an organic EL display that are used as various display devices for home use or public facilities, or for business use, television devices, displays for portable electronic devices, etc. It can be suitably used for the manufacturing method of the apparatus.

DESCRIPTION OF SYMBOLS 1 Display apparatus 100 Display panel 101 Substrate 102 TFT layer 103 Feed electrode 103a Oxide film 104 Interlayer insulation film 105 Contact hole 106 Pixel electrode 111 Organic light emitting layer 114 Counter electrode

Claims (8)

A first step of preparing a substrate on which a TFT layer including a wiring portion made of metal is formed;
A second step of laminating a layer of an insulating film material on the TFT layer;
A third step of forming a contact hole in the insulating film material layer so that a part of the wiring portion is exposed;
A fourth step of forming the insulating film layer by heating and baking the layer of the insulating film material in an atmosphere containing oxygen;
A fifth step of dissolving and removing the metal oxide formed by oxidizing the metal on the surface of the wiring portion in the fourth step in an etchant;
A pixel electrode is formed so as to be electrically connected to a part of the wiring part in the contact hole, an organic light emitting layer is formed above the pixel electrode, and a counter electrode is formed above the organic light emitting layer. And a process for producing an organic EL device, comprising: 2. The method of manufacturing an organic EL element according to claim 1, wherein in the fifth step, the surface of the contact hole is hydrophilized before the metal oxide is dissolved and removed in an etchant. The method for producing an organic EL element according to claim 2 , wherein the hydrophilization treatment is performed by ozone cleaning or ultraviolet irradiation. The method for producing an organic EL element according to claim 2, wherein the hydrophilization treatment is performed with hydrogen peroxide water or ozone water. The method for manufacturing an organic EL element according to claim 1, wherein the metal forming the wiring portion is titanium, molybdenum, or tungsten. The method of manufacturing an organic EL element according to claim 5, wherein the etchant is an acidic liquid containing oxalic acid or an alkaline liquid containing ammonia. The method of manufacturing an organic EL element according to claim 1, wherein the pixel electrode is formed of aluminum or an aluminum alloy.   The organic electroluminescence display panel which has an organic electroluminescent element obtained by the manufacturing method in any one of Claims 1-7.

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