JP2004303671A - Manufacturing method of electro-optical device, electro-optical device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To form a layer which enhances adhesiveness between an electro-optical layer as an organic matter and an electrode as an inorganic matter without depending on vapor deposition so as to correspond easily to a large substrate, regarding a manufacturing method of an electro-optical device such as an organic EL display device or the like. <P>SOLUTION: As for the manufacturing method of the electro-optical device 1 composed by laminating a first electrode 23, the electro-optical layer 60, and a second electrode 50 on a substrate 20, after the electro-optical layer 60 as an organic matter is formed on the first electrode 23, the surface of this electro-optical layer 60 is reformed by a nitrogen plasma treatment, and the second electrode 50 as an inorganic matter is formed on this reformed film 30. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing an electro-optical device, an electro-optical device manufactured by the method, and an electronic apparatus including the same.
[0002]
[Prior art]
In an electro-optical device in which a plurality of layers are stacked, the adhesiveness of each layer has a great effect on its electro-optical characteristics. For example, in an organic electroluminescence (hereinafter abbreviated as “organic EL”) device, a metal electrode (cathode) is laminated on a resin bank separating pixels and an organic EL layer serving as a light emitting layer. Has a great effect on the performance and stability of not only the electrode portion constructed in the subsequent process but also the entire device.
For this reason, it is necessary to provide a layer (adhesion-imparting layer) for increasing the adhesion between the organic resin bank or the organic EL layer and the inorganic cathode. Conventionally, such an adhesion-imparting layer has been formed by evaporating various metal elements on the organic material (for example, Patent Document 1).
[0003]
[Patent Document 1]
JP-A-2002-280184
[0004]
[Problems to be solved by the invention]
However, the method of depositing a metal thin film as described above requires a deposition mask, and it is difficult to apply the method to a large substrate.
The present invention has been made in view of the above problems, a method for manufacturing an electro-optical device capable of forming an adhesion-imparting layer without relying on vapor deposition, and an electro-optical device manufactured by this method, and furthermore, It is an object to provide an electronic device including an electro-optical device.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a method of manufacturing an electro-optical device according to the present invention includes a step of forming a first electrode on a substrate; a step of forming an electro-optical layer on the first electrode; A step of performing a surface modification of the electro-optic layer by plasma treatment; and a step of forming a second electrode on the electro-optic layer.
In the present manufacturing method, a nitride film is formed on the surface of the electro-optic layer by performing a nitrogen plasma treatment after forming the electro-optic layer. Since the nitride film has good adhesion with an inorganic substance, the nitride film functions as an adhesion imparting layer that enhances the adhesion between the electro-optic layer and the second electrode. As described above, in the present manufacturing method, the adhesion-imparting layer can be formed on the surface of the electro-optical layer only by performing the nitrogen plasma treatment without using the evaporation mask, so that the method can be easily applied to a large-sized substrate process.
[0006]
Note that various electro-optical materials such as a liquid crystal and an electroluminescent (EL) material can be applied to the electro-optical layer. Further, the electro-optical layer can be configured as a laminated film of not only a single layer but also a plurality of functional layers. For example, a plurality of functional layers such as a hole injection layer, a hole transport layer, an EL light-emitting layer, an electron transport layer, and an electron injection layer are stacked and provided between the first electrode and the second electrode. An EL element can be formed as an electro-optical element.
[0007]
According to the method of manufacturing an electro-optical device of the present invention, there is provided a bank structure having a plurality of first electrodes on a substrate and a plurality of openings on the substrate corresponding to positions where the first electrodes are formed. Forming an electro-optical layer in each opening of the bank structure; performing a surface modification of the bank structure and the electro-optical layer by nitrogen plasma processing; Forming a second electrode so as to cover the structure and each of the electro-optical layers.
[0008]
This manufacturing method is a method for manufacturing an electro-optical device in which a plurality of electro-optical elements are provided on a substrate in a state where the electro-optical elements are separated from each other by a bank structure. In this manufacturing method, the surfaces of the electro-optic layer and the bank structure are nitrogen-modified by a nitrogen plasma treatment (that is, an adhesion-imparting layer made of a nitride film is formed), and good adhesion between the second electrode and the second electrode is obtained. Is obtained. Note that when forming the second electrode, if the outer portion of the bank structure has a vertical or inverted tapered shape with respect to the substrate, the electrode may be disconnected here. For this reason, it is preferable that the angle of the surface constituting the outer portion of the bank structure with respect to the substrate surface is 110 ° or more.
[0009]
In each of the above-described manufacturing methods, the modified film (the adhesion imparting layer) formed on the surface of the electro-optical layer or the bank structure so as to obtain good adhesion between the electro-optical layer and the second electrode. ) Is preferably 0.1 nm or more. On the other hand, if the thickness of the modified film is too large, the efficiency of charge injection from the second electrode is impaired. Therefore, the thickness is preferably 10 nm or less.
[0010]
Further, it is preferable to form a gas barrier layer on the second electrode in order to increase durability against oxygen, moisture, and the like. At this time, it is preferable that the gas barrier layer be formed of a silicon compound such as silicon oxide, silicon nitride, or silicon oxynitride in order to increase the adhesion with the second electrode which is an inorganic substance. In particular, since silicon nitride and silicon oxynitride have excellent insulation properties, the gas barrier layer made of such a material also has an effect of preventing electric leakage during energization.
[0011]
In addition, in order to protect the electrodes, the electro-optical layer, and the like, it is desirable to provide a protective layer so as to cover the gas barrier layer after forming the gas barrier layer. At this time, it is preferable to provide a surface protective layer on the surface side. In this way, for example, by providing a layer having a function such as pressure resistance and abrasion resistance, antireflection properties, gas barrier properties, and ultraviolet blocking properties as a surface protective layer, the light emitting layer and the electrode, and further, the gas barrier layer is also provided. The light-emitting element can be protected by the surface protective layer, and the life of the light-emitting element can be further increased.
[0012]
Further, an electro-optical device according to the present invention is manufactured by the above-described method. According to another aspect of the invention, an electronic apparatus includes the above-described electro-optical device. Accordingly, an electronic device including a large-sized display portion with high performance and high reliability can be provided.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment]
An electro-optical device according to a first embodiment of the present invention will be described with reference to FIGS.
First, prior to describing the method for manufacturing the electro-optical device of the present invention, an EL display device using an organic electroluminescent (EL) material will be described as an example of the electro-optical device to which the method of the present invention is applied.
The wiring structure of the EL display device of this example will be described with reference to FIG.
An EL display device (electro-optical device) 1 shown in FIG. 1 is an active matrix EL display device using a thin film transistor (hereinafter, abbreviated as TFT) as a switching element.
[0014]
As shown in FIG. 1, the EL display device 1 includes a plurality of scanning lines 101, a plurality of signal lines 102 extending in a direction perpendicular to each scanning line 101, and a plurality of signal lines 102 arranged in parallel with each other. And a plurality of power supply lines 103 extending in the same direction, and a pixel region X is provided near each intersection of the scanning line 101 and the signal line 102.
The data line drive circuit 100 including a shift register, a level shifter, a video line, and an analog switch is connected to the signal line 102. The scanning line 101 is connected to a scanning line driving circuit 80 including a shift register and a level shifter.
[0015]
Further, in each of the pixel regions X, a switching TFT 112 for supplying a scanning signal to a gate electrode via the scanning line 101 and a storage capacitor for holding a pixel signal shared from the signal line 102 via the switching TFT 112 113, a driving TFT 123 in which the pixel signal held by the holding capacitor 113 is supplied to the gate electrode, and a driving current from the power supply line 103 when electrically connected to the power supply line 103 via the driving TFT 123. A pixel electrode (electrode) 23 into which the liquid crystal flows, and an electro-optical layer 110 sandwiched between the pixel electrode 23 and the cathode (electrode) 50 are provided. The pixel electrode 23, the cathode 50, and the electro-optic layer 110 form a light-emitting element (organic EL element).
[0016]
According to the EL display device 1, when the scanning line 101 is driven and the switching TFT 112 is turned on, the potential of the signal line 102 at that time is held in the storage capacitor 113, and according to the state of the storage capacitor 113. The on / off state of the driving TFT 123 is determined. Then, a current flows from the power supply line 103 to the pixel electrode 23 via the channel of the driving TFT 123, and further, a current flows to the cathode 50 via the electro-optic layer 110. The electro-optic layer 110 emits light according to the amount of current flowing therethrough.
[0017]
Next, a specific configuration of the EL display device 1 of the present example will be described with reference to FIGS.
As shown in FIG. 2, the EL display device 1 of the present embodiment includes a substrate 20 having electrical insulation and pixel electrodes connected to switching TFTs (not shown) arranged in a matrix on the substrate 20. A pixel electrode region (not shown), a power supply line (not shown) arranged around the pixel electrode region and connected to each pixel electrode, and a substantially rectangular shape in plan view located at least on the pixel electrode region. It is of an active matrix type including a pixel portion 3 (within a dashed-dotted frame in FIG. 2). In the present invention, the substrate 20 and the switching TFT and various circuits formed thereon, as described later, and the interlayer insulating film are referred to as a substrate. (In FIGS. 3 and 4, it is indicated by reference numeral 200.)
[0018]
The pixel unit 3 includes a central real display area 4 (in a two-dot chain line frame in FIG. 2) and a dummy area 5 (area between the one-dot chain line and the two-dot chain line) arranged around the real display area 4. Is divided into
In the actual display area 4, display areas R, G, and B each having a pixel electrode are arranged in a matrix at a distance from each other in the AB direction and the CD direction.
Further, scanning line driving circuits 80, 80 are arranged on both sides of the actual display area 4 in FIG. These scanning line driving circuits 80 and 80 are arranged below the dummy area 5.
[0019]
Further, an inspection circuit 90 is arranged above the actual display area 4 in FIG. The inspection circuit 90 is a circuit for inspecting the operation status of the EL display device 1 and includes, for example, an inspection information output unit (not shown) for outputting an inspection result to the outside, and displays during manufacturing or shipping. The apparatus is configured so that quality and defect inspection of the apparatus can be performed. The inspection circuit 90 is also arranged below the dummy area 5.
[0020]
The scanning line drive circuit 80 and the inspection circuit 90 are applied with the drive voltage from a predetermined power supply unit via the drive voltage conduction unit 310 (see FIG. 3) and the drive voltage conduction unit 340 (see FIG. 4). It is configured. The drive control signal and the drive voltage to the scanning line drive circuit 80 and the test circuit 90 are supplied from a predetermined main driver or the like that controls the operation of the EL display device 1 to the drive control signal conducting section 320 (see FIG. 3). The data is transmitted and applied via the drive voltage conducting section 350 (see FIG. 4). The drive control signal in this case is a command signal from a main driver or the like related to control when the scanning line drive circuit 80 and the inspection circuit 90 output signals.
[0021]
In addition, as shown in FIGS. 3 and 4, the EL display device 1 includes a pixel electrode (first electrode) 23, a light emitting layer (electro-optical layer) 60, and a cathode (second electrode) 50 on a base 200. A large number of light-emitting elements (organic EL elements) each including
Although only the light emitting layer 60 is shown as the electro-optical layer in FIGS. 3 and 4, instead of forming the electro-optical layer as a single layer as described above, the electro-optical layer may be formed as a stacked film in which a plurality of layers are stacked. it can. In fact, in the present embodiment, as will be described later, the electro-optical layer is formed of a carrier injection layer such as a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, or a carrier transport layer or a hole blocking layer (hole). It is a laminated film of a blocking layer), an electron blocking layer (electron blocking layer), and the light emitting layer.
[0022]
In the case of a so-called top emission type EL display device, the substrate main body 20 constituting the base 200 is configured to take out display light from the sealing can 604 side, which is the opposite side of the substrate 20, so that the transparent substrate and the opaque substrate Can be used. Examples of the opaque substrate include ceramics such as alumina, a metal sheet such as stainless steel, which has been subjected to an insulation treatment such as surface oxidation, a thermosetting resin or a thermoplastic resin, and a film (plastic film) thereof. Can be
[0023]
Further, in the case of a so-called back emission type EL display device, since the display light is extracted from the substrate 20 side, a transparent or translucent substrate 20 is employed. For example, glass, quartz, resin (plastic, plastic film) and the like can be mentioned, and a glass substrate is particularly preferably used. In this embodiment, a back emission type in which emitted light is extracted from the substrate body 20 side is employed.
[0024]
Further, a circuit section 11 including a driving TFT 123 for driving the pixel electrode 23 is formed on the substrate 20, and a number of light emitting elements (organic EL elements) are provided thereon. As shown in FIG. 5, the light emitting element includes a pixel electrode (first electrode) 23 functioning as an anode, a hole transport layer 70 for injecting / transporting holes from the pixel electrode 23, and an electro-optical material. The light emitting layer 60 is formed by sequentially forming a light emitting layer 60 including one organic EL material and a cathode (second electrode) 50.
Under such a configuration, the light emitting element emits light by combining the holes injected from the hole transport layer 70 with the electrons from the cathode 50 in the light emitting layer 60 thereof. I have.
[0025]
Since the pixel electrode 23 is a back-emission type in this example, ITO (indium tin oxide) or an indium oxide / zinc oxide-based amorphous transparent conductive film (Indium Zinc Oxide: IZO / I-Z-O) (registered trademark) )) (Made by Idemitsu Kosan Co., Ltd.).
As a material for forming the hole transport layer 70, for example, a polythiophene derivative, a polypyrrole derivative, or a doping material thereof is used. Specifically, a dispersion liquid of 3,4-polyethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) [trade name; Bytron-p: manufactured by Bayer AG], that is, polystyrene as a dispersion medium A dispersion in which 3,4-polyethylenedioxythiophene is dispersed in sulfonic acid and further dispersed in water is used.
[0026]
As a material for forming the light emitting layer 60, a known light emitting material capable of emitting fluorescence or phosphorescence can be used. Specifically, (poly) fluorene derivative (PF), (poly) paraphenylenevinylene derivative (PPV), polyphenylene derivative (PP), polyparaphenylene derivative (PPP), polyvinylcarbazole (PVK), polythiophene derivative, polymethyl Polysilanes such as phenylsilane (PMPS) are preferably used.
Further, these polymer materials include polymer materials such as perylene dyes, coumarin dyes, and rhodamine dyes, rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, nile red, coumarin 6, and quinacridone. , Etc., can be used.
It should be noted that a conventionally known low molecular material can be used instead of the above polymer material. Further, an electron injection layer may be formed on such a light emitting layer 60 as necessary.
[0027]
In addition, as shown in FIGS. 3 to 5, in the present embodiment, the hole transport layer 70 and the light emitting layer 60 are separated from each other by a bank structure including the lyophilic control layer 25 and the organic bank layer 221. It is arranged on the substrate 200 in a state. That is, the lyophilic control layer 25 and the organic bank layer 221 have openings at positions corresponding to the pixel electrodes 23 arranged in a matrix on the substrate 200, and the hole transport layer 70 and the light emitting layer 60 It is provided in each of the openings. In the lyophilic control layer 25 and the organic bank layer 221 formed in a lattice shape, particularly, the outermost portion of the light-emitting layer 60, which is the outermost portion of the light-emitting layer 60, is covered with this. The surrounding part is a surrounding member 201. A substantially rectangular area surrounded by the surrounding member 201 is the actual display area 4.
[0028]
Here, regarding the surrounding member 201, the angle θ of the surface 201a forming the outer portion with respect to the surface of the base 200 in the organic bank layer 221 forming the upper part thereof is 110 degrees or more. The angle is set so as to improve the step coverage of the cathode 50 formed thereon, as described later, and to ensure the continuity of the cathode on the outer portion.
[0029]
As shown in FIGS. 3 to 5, the cathode 50 has an area larger than the total area of the real display area 4 and the dummy area 5 and is formed so as to cover each of the light emitting layer 60 and the organic bank layer. 221 and the upper surface of the surrounding member 201, and further, the surface 201a forming the outer part of the surrounding member 201 is formed on the base 200 in a state of covering the surface 201a. The cathode 50 is connected to a cathode wiring 202 formed on the outer periphery of the base 200 outside the surface 201a of the surrounding member 201 as shown in FIG. A flexible substrate 203 is connected to the cathode wiring 202, whereby the cathode 50 is connected to a drive IC (drive circuit) (not shown) on the flexible substrate 203 via the cathode wiring 202. I have.
[0030]
As a material for forming the cathode 50, a high-reflectance metal material such as Al (aluminum) or Ag (silver) is used because the present example is a back emission type.
The modified film 30 is formed on the surfaces of the light emitting layer 60 and the cathode 50 by a nitrogen plasma treatment. Since such a nitride film has good adhesiveness with an inorganic material, the modified film 30 has good adhesion between the light emitting layer 60 or the bank structure, which is an organic material, and the cathode 50, which is an inorganic material. Function as an adhesion-imparting layer that enhances If the thickness of the modified film 30 is too small, sufficient adhesion cannot be obtained, and if the thickness is too large, charge injection from the cathode 50 is hindered. Therefore, the thickness of the modified film 30 is set to 0.1 nm or more and 10 nm or less. I have.
[0031]
A circuit section 11 is provided below the light emitting element as shown in FIG. The circuit section 11 is formed on the substrate 20 to configure the base 200. That is, the surface of the substrate 20 is made of SiO ₂ Is formed as a base, and a silicon layer 241 is formed thereon. On the surface of this silicon layer 241, SiO ₂ And / or a gate insulating layer 282 mainly composed of SiN is formed.
[0032]
In the silicon layer 241, a region overlapping with the gate electrode 242 with the gate insulating layer 282 interposed therebetween is a channel region 241a. The gate electrode 242 is a part of the scanning line 101 (not shown). On the other hand, on the surface of the gate insulating layer 282 covering the silicon layer 241 and forming the gate electrode 242, SiO ₂ Is formed as a first interlayer insulating layer 283.
[0033]
In the silicon layer 241, a low-concentration source region 241b and a high-concentration source region 241S are provided on the source side of the channel region 241a, while a low-concentration drain region 241c and a high-concentration drain region are provided on the drain side of the channel region 241a. The region 241D is provided to form a so-called LDD (Light Doped Drain) structure. Of these, the high-concentration source region 241S is connected to the source electrode 243 via a contact hole 243a opened over the gate insulating layer 282 and the first interlayer insulating layer 283. The source electrode 243 is configured as a part of the above-described power supply line 103 (see FIG. 1, and extends in the direction perpendicular to the paper of FIG. 5 at the position of the source electrode 243). On the other hand, the high-concentration drain region 241D is connected to a drain electrode 244 made of the same layer as the source electrode 243 via a contact hole 244a opened over the gate insulating layer 282 and the first interlayer insulating layer 283.
[0034]
The upper layer of the first interlayer insulating layer 283 on which the source electrode 243 and the drain electrode 244 are formed is covered with a second interlayer insulating layer 284 mainly composed of, for example, an acrylic resin component. The second interlayer insulating layer 284 is made of a material other than an acrylic insulating film, for example, SiN, SiO ₂ A nitrogen compound such as When a nitrogen compound having a high gas barrier property is used for the second interlayer insulating film 282 in this manner, even when the substrate body 20 is a resin substrate having a high moisture permeability, oxygen, moisture, or the like enters the light emitting layer 60 from the substrate side. Can be prevented, and the life of the light emitting element can be prolonged.
The pixel electrode 23 made of ITO is formed on the surface of the second interlayer insulating layer 284, and is connected to the drain electrode 244 via a contact hole 23a provided in the second interlayer insulating layer 284. ing. That is, the pixel electrode 23 is connected to the high-concentration drain region 241D of the silicon layer 241 via the drain electrode 244.
[0035]
Note that TFTs (TFTs for driving circuits) included in the scanning line driving circuit 80 and the inspection circuit 90, that is, N-channel or P-channel TFTs forming an inverter included in a shift register among these driving circuits, for example. Has the same structure as the driving TFT 123 except that it is not connected to the pixel electrode 23.
[0036]
On the surface of the second interlayer insulating layer 284 on which the pixel electrode 23 is formed, a bank structure including the pixel electrode 23, the lyophilic control layer 25, and the organic bank layer 221 is provided. The lyophilic control layer 25 is made of, for example, SiO 2 ₂ The organic bank layer 221 is made of, for example, acrylic or polyimide. Then, on the pixel electrode 23, the hole transport layer 70 and the light emitting layer 60 are formed inside the opening 25 a provided in the lyophilic control layer 25 and the opening 221 a surrounded by the organic bank 221. Are stacked in this order. The “lyophilicity” of the lyophilicity control layer 25 in the present example means that the lyophilicity is higher than at least the material of the organic bank layer 221 such as acrylic or polyimide.
The layers up to the second interlayer insulating layer 284 on the substrate 20 described above constitute the circuit section 11.
[0037]
Here, in the EL display device 1 of this example, in order to perform color display, each light emitting layer 60 is formed so that its emission wavelength band corresponds to each of the three primary colors of light. For example, as the light-emitting layer 60, a red light-emitting layer 60R corresponding to a light-emitting wavelength band of red, a green light-emitting layer 60G corresponding to green, and a blue organic EL layer 60B corresponding to blue have a display region R corresponding to each. , G, and B, and one pixel for performing color display is constituted by these display regions R, G, and B. A BM (black matrix) (not shown) formed by depositing metal chromium by sputtering or the like is formed between the organic bank layer 221 and the lyophilic control layer 25 at the boundary between the color display regions. I have.
[0038]
On the surface of such a substrate 200, a sealing can 604 for protecting the light emitting layer 60 and the cathode 50 from oxygen, moisture and the like is provided. The sealing can 604 is made of glass or metal, and is joined to the substrate 200 via a sealing resin 603 formed in an annular shape around the substrate 200. Further, the sealing can 603 has a recess 604a for accommodating the bank structure, the cathode 50, and the like inside thereof, and a getter material 605 for absorbing oxygen and moisture is attached to the recess 604a. . Thus, gases such as water or oxygen that have entered the inside of the sealing can 603 are absorbed, and deterioration of the element due to these gases is prevented.
[0039]
Next, as one embodiment of the present invention, an example of a method of manufacturing the EL display device 1 will be described with reference to FIGS. In the present embodiment, a case will be described in which the EL display device 1 as an electro-optical device is of a top emission type. Each of the cross-sectional views shown in FIGS. 6 and 7 corresponds to a cross-sectional view taken along line AB in FIG.
[0040]
First, as shown in FIG. 6A, a circuit portion 11 having various wirings, switching elements, interlayer insulating films and the like, and a pixel electrode 23 are formed on a substrate body 20 made of glass or the like by a known method.
[0041]
Next, as shown in FIG. 6B, a lyophilic control layer 25 as an insulating layer is formed on the pixel electrode 23 and the second interlayer insulating film 282. In the pixel electrode 23, the lyophilic control layer 25 is formed so as to be partially open, and holes can be moved from the pixel electrode 23 in the opening 25a (see also FIG. 3). Subsequently, in the lyophilic control layer 25, a BM (not shown) is formed in a concave portion formed between two different pixel electrodes 23. Specifically, a film is formed on the concave portion of the lyophilic control layer 25 by sputtering using metal chromium.
[0042]
Next, as shown in FIG. 6C, an organic bank layer 221 is formed so as to cover a predetermined position of the lyophilic control layer 25, specifically, the BM. As a specific method of forming an organic bank layer, for example, a solution obtained by dissolving a resist such as an acrylic resin or a polyimide resin in a solvent is applied by various coating methods such as spin coating and dip coating to form an organic layer. . The constituent material of the organic layer may be any material as long as it does not dissolve in the solvent of the ink described below and is easily patterned by etching or the like.
[0043]
Subsequently, the organic layer is patterned using a photolithography technique and an etching technique, and a bank opening 221a is formed in the organic layer, whereby an organic bank layer 221 having a wall surface in the opening 221a is formed. Here, in the organic bank layer 221, the angle θ with respect to the surface of the base 200 is particularly 110 ° or more with respect to the portion forming the outermost periphery, that is, the surface 201 a forming the outer portion of the enclosing member 201 in the present invention. It is preferable to form them so that By forming at such an angle, the step coverage of the cathode 50 formed thereon can be improved.
[0044]
Next, a region showing lyophilicity and a region showing lyophobicity are formed on the surface of the organic bank layer 221. In the present embodiment, each region is formed by plasma processing. Specifically, the plasma treatment is performed by performing a preheating step and making the upper surface of the organic bank layer 221 and the wall surface of the opening 221a, the electrode surface 23c of the pixel electrode 23, and the upper surface of the lyophilic control layer 25 each lyophilic. And a cooling step for making the upper surface of the organic bank layer and the wall surface of the opening lyophobic.
[0045]
That is, a substrate (the substrate 20 including a bank or the like) is heated to a predetermined temperature, for example, about 70 to 80 ° C., and then a plasma treatment (O 2) using oxygen as a reaction gas in an air atmosphere is performed as an ink-philic process. ₂ (Plasma treatment). Next, a plasma treatment (CF) using methane tetrafluoride as a reaction gas in an air atmosphere is performed as an ink repellent process. ₄ Plasma treatment) is performed, and then the substrate heated for the plasma treatment is cooled to room temperature, whereby lyophilicity and lyophobic properties are imparted to predetermined locations.
[0046]
Note that this CF ₄ In the plasma treatment, the electrode surface 23c of the pixel electrode 23 and the lyophilic control layer 25 are somewhat affected, but ITO as the material of the pixel electrode 23 and SiO as the constituent material of the lyophilic control layer 25 are used. ₂ , TiO ₂ And the like have a poor affinity for fluorine, so that the hydroxyl groups provided in the ink-lyophilization step are not replaced by fluorine groups, and lyophilicity is maintained.
[0047]
Next, the hole transport layer 70 is formed in a hole transport layer forming step. In the hole transport layer forming step, the hole transport layer material is applied on the electrode surface 23c by, for example, a droplet discharge method such as an inkjet method or a spin coating method, and thereafter, a drying process and a heat treatment are performed. A hole transporting layer 70 is formed on 23. When the hole transport layer material is selectively applied by, for example, an inkjet method, first, an inkjet head (not shown) is filled with the hole transport layer material, and the discharge nozzle of the inkjet head is applied to the lyophilic control layer 25. A droplet whose liquid amount per droplet is controlled from an ejection nozzle while moving the inkjet head and the base material (substrate 20) relatively to the electrode surface 23c located in the formed opening 25a. Discharge is performed on the electrode surface 23c. Next, the hole transport layer 70 is formed by subjecting the discharged droplets to a drying treatment and evaporating the dispersion medium and the solvent contained in the hole transport layer material.
[0048]
Here, the droplet discharged from the discharge nozzle spreads on the electrode surface 23 c on which the lyophilic processing has been performed, and fills the opening 25 a of the lyophilic control layer 25. On the other hand, on the upper surface of the organic bank layer 221 subjected to the ink-repellent treatment, the droplet is repelled and does not adhere. Therefore, even if the droplet is displaced from the predetermined ejection position and is ejected onto the upper surface of the organic bank layer 221, the upper surface is not wetted by the droplet, and the ejected droplet is discharged from the opening of the lyophilic control layer 25. Rolls into the part 25a.
Note that, after the hole transport layer forming step, it is preferable to perform the step in an inert gas atmosphere such as a nitrogen atmosphere or an argon atmosphere in order to prevent oxidation of the hole transport layer 70 and the light emitting layer 60.
[0049]
Next, the light emitting layer 60 is formed in a light emitting layer forming step. In this light emitting layer forming step, the light emitting layer forming material is discharged onto the hole transporting layer 70 by, for example, the above-described ink jet method, and thereafter, the drying process and the heat treatment are performed. The light emitting layer 60 is formed in 221a. In this light emitting layer forming step, a non-polar solvent insoluble in the hole transporting layer 70 is used as a solvent for the light emitting layer forming material in order to prevent the hole transporting layer 70 from being redissolved.
In this light-emitting layer forming step, for example, a blue (B) light-emitting layer forming material is selectively applied to the blue display region by the above-described ink-jet method, dried, and then green (G) and red in the same manner. (R) is also selectively applied to its display area and dried.
If necessary, an electron injection layer may be formed on such a light emitting layer 60 as described above.
[0050]
Next, as shown in FIG. 7D, a nitrogen plasma treatment is performed on the substrate 200 under normal pressure or reduced pressure, and the nitrogen-modified film 30 is formed on the surfaces of the organic bank layer 221 (including the surrounding member 201) and the light emitting layer 60. To form In order to obtain sufficient adhesion without impairing the charge injection efficiency from the cathode 50, the thickness of the modified film 30 is set to 0.1 nm or more and 10 nm or less. Specifically, nitrogen plasma is generated by ECR plasma, RF plasma, capacitively-coupled plasma, inductively-coupled plasma, or the like, and the nitrogen modified film 30 is formed on the light emitting layer. In the surface modification step, an inert gas such as argon or helium may be added as the introduced gas in addition to the nitrogen.
[0051]
Next, as shown in FIG. 7E, a cathode 50 is formed by a cathode layer forming step. In this cathode layer forming step, a metal film having a high reflectivity such as Al is formed under reduced pressure by a physical vapor deposition method such as a vapor deposition method to form a cathode 50. At this time, the cathode 50 covers not only the light emitting layer 60, the organic bank layer 221, and the upper surface of the surrounding member 201, but also covers the surface 201 a forming the outer portion of the surrounding member 201. It is formed as follows.
[0052]
Then, finally, the surface of the substrate 200 on which the light emitting element is formed is sealed by a sealing step. In this sealing step, for example, a sealing resin 604 made of a thermosetting resin or an ultraviolet-curing resin is applied to the peripheral portion of the substrate 200, and the substrate 200 and the sealing can 603 are separated via the sealing resin 604. Join. Note that this sealing step is preferably performed in an atmosphere of an inert gas such as nitrogen, argon, or helium.
[0053]
In the method of manufacturing such an EL display device 1, since the cathode 50 is formed in a state where the surface of the organic light emitting layer 60 or the bank structure is nitrided by nitrogen plasma treatment, the light emitting layer 60, Good adhesion is obtained between the bank structure and the cathode 50. Thus, the film formation state of the cathode 50 is improved, and the electronic function can be maintained for a long time. Since the thickness of the modified film 30 as the adhesion-imparting layer is extremely small, it does not affect the electrical characteristics.
Further, since the modified film 30 is formed by the plasma treatment, a mask is not required unlike the vapor deposition method, and it is possible to relatively easily cope with a large substrate.
[0054]
[Second embodiment]
Next, an electro-optical device according to a second embodiment of the invention will be described with reference to FIG.
The electro-optical device 1 ′ of this embodiment is different from the first embodiment in that the gas barrier layer 40 is provided on the cathode 50 ′ instead of sealing the substrate surface with a can. A protective layer 204 is provided. The electro-optical device 1 'is a top emission type EL display device that emits light emitted from the cathode side. Transparent members are used for the cathode 50', the gas barrier layer 40, and the protective layer 204. For example, a metal oxide such as ITO or IZO is used as the cathode 50 '.
[0055]
The gas barrier layer 40 is for preventing oxygen and moisture from entering the inside thereof, thereby preventing oxygen and moisture from entering the cathode 50 and the light emitting layer 60, and the cathode 50 'due to oxygen and moisture. And deterioration of the light emitting layer 60 and the like. The gas barrier layer 40 is made of a light-transmitting inorganic compound formed by a low-pressure vapor deposition method (sputtering, plasma CVD, or the like) in a low-temperature plasma atmosphere, and is preferably a silicon compound such as silicon nitride or silicon oxide. It is formed of nitride, silicon oxide, or the like. By forming the gas barrier layer 40 with a silicon compound in this way, the gas barrier layer becomes a dense film, and good gas barrier performance can be obtained.
The gas barrier layer 40 is formed so as to cover the entire cathode 50 ′ and contact the second interlayer insulating film 282. In such a configuration, for example, by forming the second interlayer insulating film 282 from a silicon compound having a high gas barrier performance such as SiO 2 or SiN, all of the upper layer, the lower layer, and the side portion of the light emitting element portion are covered with the silicon compound. As a result, the moisture resistance and oxygen resistance of the device can be significantly improved.
[0056]
The protection layer 204 includes a buffer layer 205 provided on the gas barrier layer 40 side and a surface protection layer 206 provided thereon. The buffer layer 205 is in close contact with the gas barrier layer 40 and has a buffer function against mechanical shock from the outside. For example, the buffer layer 205 is a transparent resin such as urethane, acrylic, epoxy, or polyolefin, and will be described later. It is formed of an adhesive made of a material that is more flexible than the surface protective layer 206 and has a low glass transition point. It is preferable to add a silane coupling agent or an alkoxysilane to such an adhesive, and in this case, the adhesion between the formed buffer layer 205 and the gas barrier layer 40 can be improved. Therefore, the cushioning function against mechanical shock is enhanced. In particular, when the gas barrier layer 40 is formed of a silicon compound, the adhesion to the gas barrier layer 40 can be improved by the silane coupling agent or the alkoxysilane, and therefore, the gas barrier property of the gas barrier layer can be improved. Can be.
[0057]
The surface protective layer 206 is provided on the buffer layer 205 to constitute the surface side of the protective layer 204, and has a pressure resistance, an abrasion resistance, an external light reflection preventing property, a gas barrier property, an ultraviolet blocking property, and the like. It is a transparent layer having at least one of the functions. Specifically, it is formed of a polymer layer (plastic film), a DLC (diamond-like carbon) layer, glass, or the like.
[0058]
When the protective layer 204 is provided on the gas barrier layer 40 in this manner, the surface protective layer 206 has functions such as pressure resistance, abrasion resistance, light reflection prevention, gas barrier properties, and ultraviolet blocking properties. The light emitting layer 60, the cathode 50 ', and the gas barrier layer 40 can also be protected by the surface protective layer 206, so that the life of the light emitting element can be extended.
Further, since the buffer layer 205 exhibits a buffer function against mechanical shock, when a mechanical shock is applied from the outside, the mechanical shock to the gas barrier layer 40 and the light emitting element inside the gas barrier layer 40 is reduced, and this mechanical It is possible to prevent functional deterioration of the light emitting element due to mechanical shock.
[0059]
Next, the electronic device of the present invention will be described. An electronic apparatus according to an embodiment of the invention includes the above-described EL display device (electro-optical device) as a display unit, and specifically includes an electronic device illustrated in FIG.
FIG. 9 is a perspective view showing an example of a mobile phone. In FIG. 9, reference numeral 1000 denotes a mobile phone main body, and reference numeral 1001 denotes a display unit using the EL display device.
Since the electronic device illustrated in FIG. 9 includes the display unit including the EL display device (electro-optical device), a high-quality display with high electric performance can be obtained.
[0060]
Note that the present invention is not limited to the above-described embodiment, and can be implemented in various modifications without departing from the spirit of the present invention.
For example, in the first embodiment, the bottom emission type configuration is used, and in the second embodiment, the top emission type configuration is adopted. However, which one to adopt can be arbitrarily determined. It is also possible to adopt a configuration in which emitted light is extracted from both the substrate body side and the cathode side. In this case, it is necessary to use a transparent conductive material for both the anode and the cathode.
[0061]
In the EL display device of each embodiment, the first electrode functions as an anode and the second electrode functions as a cathode in the present invention. May be configured to function as the anodes. However, in that case, it is necessary to switch the formation positions of the light emitting layer 60 and the hole transport layer 70.
Furthermore, the configuration of the circuit unit 11 shown in each of the above embodiments is merely an example, and other configurations can of course be employed.
[0062]
Further, in the above-described embodiment, an example in which the EL display device 1 is applied to the electro-optical device of the present invention is described. However, the present invention is not limited to this, and a plurality of layers are stacked to exhibit an electrical function. Anything is acceptable.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating a wiring structure of an electro-optical device according to a first embodiment of the invention.
FIG. 2 is a plan view schematically showing a configuration of the electro-optical device.
FIG. 3 is a sectional view taken along line AB in FIG. 2;
FIG. 4 is a sectional view taken along line CD of FIG. 2;
FIG. 5 is an enlarged sectional view of a main part of FIG. 3;
FIG. 6 is a sectional view for explaining a method of manufacturing the electro-optical device in the order of steps.
FIG. 7 is a cross-sectional view for explaining a step following the step shown in FIG. 6;
FIG. 8 is a sectional view of an electro-optical device according to a second embodiment of the invention.
FIG. 9 is a perspective view illustrating an example of an electronic apparatus according to the invention.
[Explanation of symbols]
1, 1 'EL display device (electro-optical device), 23 pixel electrode (first electrode), 30 modified film, 40 gas barrier layer, 50, 50' cathode (second electrode), 60 ... Emission layer (electro-optic layer), 200 ... Substrate, 204 ... Protective layer, 205 ... Buffer layer, 206 ... Surface protective layer, 1000 ... Mobile phone (electronic equipment)

Claims (11)

Forming a first electrode on the substrate;
Forming an electro-optic layer on the first electrode;
Performing a surface modification of the electro-optical layer by a nitrogen plasma treatment;
Forming a second electrode on the electro-optic layer. 2. The method of manufacturing an electro-optical device according to claim 1, wherein the thickness of the modified film formed on the surface of the electro-optical layer in the surface modification step is 0.1 nm or more and 10 nm or less. . Forming a plurality of first electrodes on the substrate;
Forming a bank structure having a plurality of openings corresponding to the formation position of the first electrode on the substrate;
Forming an electro-optic layer in each opening of the bank structure,
Performing a surface modification of the bank structure and the electro-optical layer by nitrogen plasma processing;
Forming a second electrode so as to cover the bank structure and each of the electro-optical layers. 4. The electric device according to claim 3, wherein the thickness of the modified film formed on the surfaces of the electro-optical layer and the bank structure by the surface modification step is 0.1 nm or more and 10 nm or less. A method for manufacturing an optical device. The method of manufacturing an electro-optical device according to claim 3, wherein an angle of a surface forming an outer portion of the bank structure with respect to the substrate surface is 110 ° or more. The method of manufacturing an electro-optical device according to claim 1, further comprising a step of forming a gas barrier layer on the second electrode. 7. The method according to claim 6, wherein the gas barrier layer is formed of a silicon compound. 8. The method for manufacturing an electro-optical device according to claim 6, further comprising a step of providing a protective layer so as to cover the gas barrier layer. 9. The method according to claim 8, wherein the step of providing the protective layer includes a step of providing a surface protective layer on the surface side. An electro-optical device manufactured by the method according to claim 1. An electronic apparatus comprising the electro-optical device according to claim 10.

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