JP2003282272A - Electro-optic device, its manufacturing method, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electro-optic device stabilizing initial characteristics and life characteristics. <P>SOLUTION: The electro-optic device formed by disposing on a substrate a light emitting device having a luminescent layer between a pair of electrodes is characterized in that recesses/projections are provided on the surface of the luminescent layer side of, at least, one of the pair of electrodes. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electro-optical device, a method of manufacturing the same, and electronic equipment.

[0002]

2. Description of the Related Art In recent years, as a flat display device, a color display device in which a light emitting layer is sandwiched between an anode and a cathode, particularly an organic EL (electroluminescence) device using an organic light emitting material as a light emitting material has been developed. Is being done. This organic EL device is a transparent substrate such as a glass substrate on which indium tin oxide (ITO), Sn
An anode made of a transparent conductive material such as O ₂ (tin oxide), a light emitting layer made of an organic EL material, and a cathode made of a refractory metal material such as Al or a metal compound are sequentially laminated. It is produced by adopting a method of patterning the light emitting material by an ink jet method or the like in which a light emitting material such as an organic fluorescent material is made into ink and the ink (composition) is ejected onto a substrate.

In this organic EL device, light emitted from the light emitting element to the substrate side is transmitted through the substrate and emitted to the lower side of the substrate (observer side), and at the same time from the light emitting element to the opposite side of the substrate. The emitted light is reflected by the cathode, transmitted through the substrate, and emitted to the lower side (observer side) of the substrate.

[0004]

By the way, in the conventional organic EL device, the transparent electrode material such as ITO or SnO ₂ which is generally used in the liquid crystal display device is often used as it is as the material of the pixel electrode. But organic E
In order to improve the initial characteristics and the life characteristics of the L device, various studies have been made on these transparent electrode materials such as the resistance value and the transmittance in the visible light region. In the course of these various studies, it has become clear that there is a problem that the initial characteristics and the life characteristics of the organic EL device are significantly deteriorated when the flatness of the pixel electrode is impaired.

For example, when a transparent electrode material is formed without considering the surface roughness of the substrate, the flatness of the obtained pixel electrode may be significantly impaired. In this case, the initial characteristics and the life characteristics of the organic EL display device are significantly deteriorated. Further, as a method of improving the characteristics of the organic EL device, there is a method of increasing the hole injection efficiency by performing oxygen plasma treatment on the surface of the pixel electrode, but the flatness of the pixel electrode is improved by performing oxygen plasma treatment. In some cases, the initial characteristics and the life characteristics of the organic EL display device are significantly deteriorated.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an electro-optical device capable of stabilizing initial characteristics and life characteristics, a method of manufacturing the same, and an electronic apparatus.

[0007]

In order to achieve the above object, the present invention has the following constitutions. The electro-optical device of the present invention is an electro-optical device in which a light emitting element having a light emitting layer between a pair of electrodes is formed on a substrate, and at least one of the pair of electrodes has a surface on the light emitting layer side. It is characterized by having irregularities.

In this electro-optical device, since the surface of at least one of the pair of electrodes on the side of the light emitting layer has irregularities, the electrical roughness of the light emitting layer is caused by the surface roughness of the one electrode. The deterioration of the characteristics is prevented, and the initial characteristics and the life characteristics of the electro-optical device are stabilized. This makes it possible to provide an electro-optical device having stable initial characteristics and life characteristics.

The light emitting layer is made of an organic polymer. Further, the one electrode is made of indium tin oxide or tin oxide. Further, the surface roughness of the surface having the irregularities is 0.5 to 50.
It is characterized in that it is nm.

A method of manufacturing an electro-optical device according to the present invention is a method of manufacturing an electro-optical device in which a light emitting element having a light emitting layer between a pair of electrodes is formed on one surface of a substrate, wherein the light emitting layer side is provided. At least one of the pair of electrodes is formed so as to have unevenness.

In this method of manufacturing the electro-optical device, the flatness of the one electrode is impaired by forming at least one electrode of the pair of electrodes so as to have irregularities on the light emitting layer side. In addition, the electrical characteristics of the light emitting layer are improved. This makes it possible to easily manufacture an electro-optical device having stable initial characteristics and life characteristics.

Further, after the film formation of the one electrode, the one electrode is subjected to a surface treatment so that the surface roughness does not change within a predetermined range. In the method of manufacturing the electro-optical device, after the one electrode is formed into a film, its surface roughness does not change within a predetermined range.
By subjecting the one electrode to the surface treatment, the work function and wettability of the one electrode are improved, and the electrical characteristics of the light emitting layer are further improved. This makes it possible to easily manufacture an electro-optical device having more stable initial characteristics and life characteristics.

Further, the surface treatment is characterized in that it is one or two selected from oxygen plasma treatment and ultraviolet treatment.

An electronic apparatus according to the present invention is characterized by including any one of the electro-optical devices described above.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An electro-optical device, a method of manufacturing the same, and an electronic apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In this embodiment, an organic EL device will be described as an example of the electro-optical device. 1 to 24, in order to make each layer and each member recognizable in the drawings, the scale of each layer and each member is shown differently from the actual scale.

[First Embodiment] A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the wiring structure of the organic EL device of this embodiment, and FIG. 2 is a diagram showing the structure of the organic EL device of this embodiment.
Is a plan view of the same, and FIG. 2B is a sectional view taken along the line AA of FIG.

As shown in FIG. 1, the organic EL device 1 includes a plurality of scanning lines 101, ... And a plurality of signal lines 102, ... Which extend in a direction orthogonal to each scanning line 101.
And a plurality of power supply lines 10 extending in parallel with each signal line 102.
3 and ... are respectively wired, and
A pixel area A is provided near each intersection of the scanning line 101 and the signal line 102.

A data side driving circuit 104 including a shift register, a level shifter, a video line and an analog switch is connected to the signal line 102. Further, the scanning line driving circuit 105 including a shift register and a level shifter is connected to the scanning line 101. Further, in each pixel area A, a switching thin film transistor 112 to which a scanning signal is supplied to the gate electrode via the scanning line 101, and the switching thin film transistor 11
A holding capacitor 113 for holding a pixel signal shared from the signal line 102 via 2, a driving thin film transistor 123 to which the pixel signal held by the holding capacitor 113 is supplied to a gate electrode, and the driving thin film transistor 1
A pixel electrode (electrode) 111 into which a driving current flows from the power supply line 103 when electrically connected to the power supply line 103 via 23, and the pixel electrode 111 and the cathode (counter electrode)
12 and the functional layer 110 sandwiched therebetween. The pixel electrode 111, the cathode 12, and the functional layer 110 form a light emitting element.

According to this organic EL device 1, the scanning line 10
1 is driven to switch thin film transistor 11
When 2 is turned on, the potential of the signal line 102 at that time is held in the holding capacitor 113, and the on / off state of the driving thin film transistor 123 is determined depending on the state of the holding capacitor 113. Then, the driving thin film transistor 1
Pixel electrode 1 from the power supply line 103 through the channel of 23.
A current flows through the cathode 11, and the cathode 12 through the functional layer 110.
Current flows through. The functional layer 110 emits light according to the amount of current flowing through it.

As shown in FIGS. 2A and 2B, the organic EL device 1 includes a transparent substrate 2 and light emitting elements formed on the substrate 2 and arranged in a matrix. The light emitting element section 11 is provided. This light emitting element
It is composed of a pixel electrode 111, a cathode 12, and a functional layer 110. The substrate 2 is made of, for example, glass that is transparent to visible light, and the surface of the substrate 2 is a substantially rectangular display region 2a located at the center and a display region 2a located at the periphery of the substrate 2. And a non-display area 2b that surrounds the. The display area 2a is an area formed by the light emitting elements arranged in a matrix.
The non-display area 2b formed on the outer side of a includes the display area 2
A dummy display area 2d adjacent to a is formed.

As shown in FIG. 2B, a circuit element section 14 is provided between the light emitting element section 11 and the substrate 2, and the circuit element section 14 has the above-mentioned scanning lines, signal lines and storage capacitors. ,
A thin film transistor for switching, a thin film transistor 123 for driving, and the like are provided. In addition, the cathode 12
Has one end connected to the cathode wiring 12a, and one end of the cathode wiring 12a is connected to the wiring 5a on the flexible substrate 5 provided at one end of the substrate 2.
The wiring 5a is connected to a driving IC (driving circuit) 6 provided on the flexible substrate 5.

Further, in the non-display area 2b of the circuit element portion 14, the above-mentioned power supply line 103 (103R, 103G, 103) is used.
B) is wired. In addition, the display area 2a shown in FIG.
(A) The scanning side drive circuits 105 and 10 are provided on both sides in the middle.
5 are arranged. The scanning side drive circuits 105, 10
5 is provided in the circuit element portion 14 below the dummy region 2d. Further, in the circuit element section 14, the driving circuit control signal wiring 1 connected to the scanning side driving circuits 105, 105.
05a and the drive circuit power supply wiring 105b are provided. Further, an inspection circuit 106 is arranged above the display area 2a in FIG. 2 (a). The inspection circuit 106 can inspect the quality and defects of the display device during manufacturing or at the time of shipping.

A sealing portion 3 is provided on the light emitting element portion 11. As shown in FIG. 2B, the sealing portion 3 has a sealing resin 603 formed in an annular shape around the substrate 2.
And a sealing can 604 provided on the sealing resin 603. The sealing resin 603 is composed of a thermosetting resin, an ultraviolet curable resin, or the like, and a thermosetting or ultraviolet curable epoxy resin is particularly preferably used. As the sealing resin 603, for example, a liquid or viscous thermosetting resin or an ultraviolet curable resin is applied by a microdispenser or the like, and thereafter, it is cured by heating with a hot plate or the like or by irradiation with ultraviolet rays from an ultraviolet lamp or the like. It is a thing.

The sealing can 604 is made of glass or metal and is bonded to the substrate 2 via a sealing resin 603, and a recess 604a for accommodating the display element 10 is provided inside thereof.
Are formed. A getter agent 605 that absorbs water, oxygen and the like is attached to the concave portion 604a so that water or gas such as oxygen that has entered the inside of the sealing can 604 can be absorbed. The getter agent 605 may be omitted. The sealing resin 603 and the sealing can 604 prevent water or oxygen from entering the inside of the sealing can 604 from between the substrate 2 and the sealing can 604, and are formed in the cathode 12 or the light emitting element portion 11. The light emitting layer (not shown) is prevented from being oxidized or deteriorated.

Next, the display area of the organic EL device 1 of this embodiment will be described in more detail. Figure 3 shows this organic E
FIG. 3 is an enlarged cross-sectional view showing a display area of the L device 1.
In FIG. 3, three pixel areas A are shown. This organic EL
The display device 1 includes a circuit element portion 14 in which a circuit such as a TFT is formed on a substrate 2, a pixel electrode (one electrode of a pair of electrodes) 111, a cathode 12, and a functional layer 110. The light emitting element section 11 having the above is sequentially laminated.

In this organic EL device 1, the functional layer 1
Light emitted from 10 to the substrate 2 side is transmitted to the lower side (observer side) of the substrate 2 after passing through the circuit element portion 14 and the substrate 2, and emitted from the functional layer 110 to the opposite side of the substrate 2. The light is reflected by the cathode 12, passes through the circuit element portion 14 and the substrate 2, and is emitted to the lower side (observer side) of the substrate 2. By using a transparent material for the cathode 12, emitted light can be emitted from the cathode 12 side. As the transparent material, for example, indium tin oxide (ITO) can be used.

Further, the light emitting element section 11 is provided between the pixel electrodes 111 and the functional layer 110 and the functional layer 110 laminated on each of the plurality of pixel electrodes 111, and partitions each functional layer 110. The bank 112 is mainly formed, and the cathode 12 is disposed on the functional layer 110. The pixel electrode 111, the functional layer 110, and the cathode 12 constitute the light emitting element unit 11.

Here, the pixel electrode 111 is, for example, IT.
It is formed of a transparent conductive material such as O, and is formed by patterning into a substantially rectangular shape in plan view. The film thickness of the pixel electrode 111 is preferably in the range of 50 to 200 nm, and particularly preferably about 150 nm.

Further, the surface roughness (R
a) is preferably in the range of 0.9 to 30 nm, and particularly preferably 0.
9-10 nm is preferable. The reason for setting the surface roughness (Ra) of the pixel electrode 111 in the range of 0.9 to 30 nm is I
When a low molecular weight or high molecular weight organic layer such as a hole transport layer and a light emitting layer laminated on the TO is formed in a range of 50 to 80 nm and the light emitting characteristics and the life are optimized, ITO is used.
Due to the constraint that the surface roughness Ra (nm) above does not exceed the film thickness of at least one organic layer, the surface roughness R
The maximum allowable value (30 nm) of a (nm) is determined. With respect to this maximum allowable value, the range of the surface roughness Ra (nm) on the ITO becomes smaller as the organic layer laminated thereon becomes thinner. The minimum value of the surface roughness (Ra) is the surface roughness Ra.
(Nm) = 0 nm is excluded in terms of measurement and physical impossibility, and the ITO currently used has the smallest surface roughness Ra (nm) of 0.8 nm.
The minimum value of surface roughness (Ra) is 0.9n in consideration of tolerance.
defined as m.

As shown in FIG. 3, the bank portion 112 has an inorganic bank layer 112a located on the substrate 2 side, and is laminated on the inorganic bank layer 112a so as to be stacked on the inorganic bank layer 112a.
The organic bank layer 112b is narrower than 12a. The inorganic bank layer 112a is formed so that the peripheral edge portion thereof rides on the peripheral edge portion of the pixel electrode 111. In plan view, it has a structure in which the periphery of the pixel electrode 111 and the periphery of the inorganic bank layer 112a are arranged so as to overlap each other in plan view. In addition, the organic bank layer 112b
Similarly, a part thereof is arranged so as to planarly overlap the peripheral portion of the pixel electrode 111.

The inorganic bank layer 112a is further formed closer to the center of the pixel electrode 111 than the organic bank layer 112b. In this way, the inorganic bank layer 112
By forming each first laminated portion 112e of a inside the pixel electrode 111, the lower opening 112c corresponding to the formation position of the pixel electrode 111 is formed. Similarly, in the organic bank layer 112b, the upper opening 112d is formed so as to correspond to the lower opening 112c.
The upper opening 112d is wider than the lower opening 112c and narrower than the pixel electrode 111.

The inorganic bank layer 112a is made of, for example, Si.
Inorganic materials such as O ₂ and TiO ₂ are preferably used. The thickness of the inorganic bank layer 112a is preferably in the range of 50 to 200 nm, and particularly preferably 150 nm. The reason is that when the film thickness is less than 50 nm, the inorganic bank layer 112a is
Becomes thinner than the hole injection / transport layer described later,
This is because the flatness of the transport layer cannot be ensured.
This is because if the film thickness exceeds 200 nm, the step difference due to the lower opening 112c becomes large, and the flatness of the later-described light emitting layer laminated on the hole injecting / transporting layer cannot be ensured.

For the organic bank layer 112b, an organic material having heat resistance and solvent resistance, for example, a material having heat resistance and solvent resistance such as acrylic resin and polyimide resin is preferably used. The organic bank layer 112b has a thickness of 0.
The range of 1 to 3.5 μm is preferable, and about 2 μm is particularly preferable. The reason is that if the thickness is less than 0.1 μm, the organic bank layer 112b becomes thinner than the total thickness of the hole injecting / transporting layer and the light emitting layer described later, and the light emitting layer may overflow from the upper opening 112d. And when the thickness exceeds 3.5 μm, the upper opening 112d
This is because the step difference becomes large and the step coverage of the cathode 12 formed on the organic bank layer 112b cannot be secured. If the organic bank layer 112b has a thickness of 2 μm or more, the driving thin film transistor 12 will be described.
It is more preferable because the insulating property with respect to 3 can be improved.

The bank portion 112 has a lyophilic region and a lyophobic region. The lyophilic region is the first laminated portion 112 of the inorganic bank layer 112a.
e and the electrode surface 111a of the pixel electrode 111, and these regions are surface-treated to be lyophilic by plasma treatment using oxygen as a treatment gas. The liquid-repellent areas are the side surfaces (wall surfaces) of the upper opening 112d and the upper surface 112f of the organic bank layer 112b, and these areas are tetrafluoromethane, tetrafluoromethane, carbon tetrafluoride, or the like. The surface is fluorinated (liquid-repellent treatment) by plasma treatment using a gas as a treatment gas to make it liquid-repellent.

The functional layer 110 is composed of a hole injection / transport layer 110a laminated on the pixel electrode 111 and a light emitting layer 110b formed on the hole injection / transport layer 110a. Note that another functional layer may be further formed on the light emitting layer 110b. For example, it is possible to form an electron transport layer. The hole injection / transport layer 110a has a function of injecting holes into the light emitting layer 110b and transporting the injected holes in the hole injection / transport layer 110a. By forming such a hole injecting / transporting layer 110a between the pixel electrode 111 and the light emitting layer 110b, device characteristics such as light emitting efficiency and life of the light emitting layer 110b can be improved. In the light emitting layer 110b, the holes injected from the hole injection / transport layer 110a and the cathode 1
Electrons injected from 2 form excitons, and the excitons recombine to obtain light emission (EL).

The hole injecting / transporting layer 110a is located in the lower opening 112c and is located on the electrode surface 111a of the pixel electrode 111.
The flat portion 110a1 formed above and the upper opening 112
the first bank portion 1 of the inorganic bank layer 112a located in the space d.
It is composed of a peripheral portion 110a2 formed on 12e. Further, depending on the structure, the hole injection / transport layer 110a is formed on the pixel electrode 111 and only in the lower opening 110c, that is, the flat portion 110.
The configuration of only a1 may be used. This flat portion 110a1
Has a constant thickness, for example, a thickness in the range of 50 to 70 nm.

The light emitting layer 110b is the hole injecting / transporting layer 11
0a is formed over the flat portion 110a1 and the peripheral portion 110a2 and has a thickness of 50 on the flat portion 112a1.
The range is -80 nm. The light emitting layer 110b includes a red light emitting layer 110b1 that emits red light (R) and a green light (G).
The light emitting layers 110b1 to 110b3 are arranged in stripes. The green light emitting layer 110b2 emits green light and the blue light emitting layer 110b3 emits blue light (B).

The upper surface 11 of the organic bank layer 112b
Since 2f exhibits liquid repellency, the ejected droplets are selectively patterned within the pixel. The hole injection / transport layer 1
As a material for forming 10a, for example, Bytron-p (manufactured by Bayer) can be used.

As the light emitting material forming the light emitting layer 110b, a known light emitting material capable of emitting fluorescence or phosphorescence can be used. Specifically, (poly) fluorene derivative (PF), (poly) paraphenylene vinylene derivative (PPV), polyphenylene derivative (PP), polyparaphenylene derivative (PPP), polyvinylcarbazole (PVK), polythiophene derivative, polymethyl Polysilane-based materials such as phenylsilane (PMPS) are preferably used. In addition to these polymeric materials, polymeric materials such as perylene-based pigments, coumarin-based pigments, rhodamine-based pigments, or rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6, A low molecular weight material such as quinacridone can be doped and used.

The cathode 12 is formed on the entire surface of the light emitting element section 11, and is paired with the pixel electrode 111 to form the functional layer 110.
Play a role in passing current through. The cathode 12 is, for example,
It is configured by laminating a calcium layer and an aluminum layer. At this time, a material having a small work function for the cathode on the side closer to the light emitting layer, for example, alkali metals such as sodium, potassium, lithium, rubidium, cesium, and alkaline earth metals such as magnesium, calcium, strontium, barium, yttrium, and lanthanoid It is preferable to provide a rare earth element composed of ## STR3 ## and in this embodiment, the luminescent layer 110 is in direct contact with the luminescent layer 110b.
It serves to inject current into b.

The cathode 12 also has a function of reflecting the light emitted from the light emitting layer 110b to the substrate 2 side, and the material constituting the cathode 12 is reflection of light such as aluminum (Al) and silver (Ag). A high reflectance material having a high index is preferably used. As the high reflectance material, a single layer film such as an Al film or an Ag film, or a laminated film of Al and Ag is preferably used. The thickness is preferably in the range of, for example, 100 to 1000 nm, and particularly preferably about 200 nm. Further, a protective layer made of SiO ₂ , SiO _x N _y or the like for preventing oxygen and moisture permeation (for gas barrier) may be provided on this film.

Depending on the material of the light emitting layer, in order to emit light efficiently, Li is provided between the light emitting layer 110 and the cathode 12.
Fluoride, oxide, chelate complex, or organic substance having an electron transporting property of alkali metal or alkaline earth metal such as F (lithium fluoride) may be used. This LiF
The thickness of the layer is preferably in the range of 0.1 to 5 nm,
Further, the thickness of the Ca layer is preferably in the range of 1 to 50 nm, for example. A sealing can 604 is arranged on the light emitting element. As shown in FIG. 2B, the sealing can 604 is bonded with the sealing resin 603 to form the organic EL device 1.

Next, a method of manufacturing the organic EL device of this embodiment will be described with reference to the drawings. The method of manufacturing the organic EL device 1 of the present embodiment includes, for example, (1) pixel electrode forming step, (2)
Bank portion forming step, (3) plasma treatment step, (4) hole injection / transport layer forming step, (5) light emitting layer forming step, (6) counter electrode forming step, (7) sealing step, for a total of 7 steps It is composed by. Note that this manufacturing method is not limited to this embodiment, and if other steps are omitted as necessary,
It may also be added.

(1) Pixel Electrode Forming Step The pixel electrode forming step is a step of forming the pixel electrode 111 at a predetermined position on the substrate 2. This pixel electrode forming step is composed of a total of three steps including (1) -1 transparent conductive film forming step, (1) -2 transparent conductive film surface treatment step, and (1) -3 pixel electrode forming step.

(1) -1 Transparent Conductive Film Forming Step This transparent conductive film forming step is a step of forming the transparent conductive film 107 on the entire surface of the circuit element portion 14 of the substrate 2. As shown in FIG. 4, a substrate 2 having a circuit element portion 14 on which circuits such as TFTs are formed is provided on the surface.
A transparent conductive film 107 made of a transparent conductive material is formed on the entire surface of the circuit element portion 14 by, for example, a sputtering method.
When forming the transparent conductive film 107, the film forming conditions of the transparent conductive film 107 are set such that the surface roughness of the obtained pixel electrode 111 is within a range in which the electrical characteristics of the light emitting layer 110 do not change. .

In this pixel electrode forming step, a target made of a transparent conductive film forming material such as tin oxide (Sn oxide) is placed in the bell jar (film forming chamber) of the high frequency sputtering apparatus.
Indium oxide (In) containing 0 to 10% by weight of O _2
A metal oxide target made of ₂ O ₃ ) and the substrate 2 are arranged to face each other, and a carrier gas, for example, an argon (O ₂ ) gas containing 0.2 to 2.0 v / v% argon ( Ar) gas is introduced, and a predetermined high frequency power is applied between the substrate 2 and the metal oxide target in a state where the Ar gas pressure in the bell jar is set to a predetermined gas pressure. As a result, the atomic particles blown out from the metal oxide target are deposited on the circuit element portion 14 of the substrate 2.
As a result, the transparent conductive film 107 made of ITO is formed on the entire surface of the circuit element portion 14 of the substrate 2.

The above film forming conditions are as follows: (specified pressure) degree of vacuum Ar gas pressure: 5 to 6 × 10 ⁻⁵ Pa, high frequency power: 1000 to 3000 W, substrate temperature: 25 to 250 ° C., film forming rate: 1 to 100 nm / min Is. The film thickness, the sheet resistance and the surface roughness of the transparent conductive film 107 (ITO) are as follows: film thickness: 50 to 200 nm Sheet resistance: 5 to 100 Ω · cm / □ Surface roughness (Ra): 0.6 to 30 nm is there.

(1) -2 Transparent conductive film surface treatment step In this transparent conductive film surface treatment step, the transparent conductive film 107 is subjected to surface treatment such as oxygen plasma treatment, UV ozone cleaning (ultraviolet treatment). This surface treatment is performed on the pixel electrode 1
This is performed to increase the hole injection efficiency in 11, and is performed by oxygen plasma treatment and UV ozone cleaning (ultraviolet treatment) individually or in combination. Here, a two-step process of performing UV ozone cleaning after the oxygen plasma process is performed.

The oxygen plasma treatment is performed using a plasma device as shown in FIG. An example of the conditions in this case is given below. Gap between substrate and plasma discharge electrode: 0.5-2 mm Power: 300 W Oxygen gas flow rate: 50-100 ml / min Substrate transport speed: 0.5-10 mm / sec Substrate temperature: 25-300 ° C

As a condition for UV ozone cleaning, a UV lamp having a wavelength of 172 nm or 254 nm is used.
The distance between the substrate and the UV lamp is 0.5 to 200 mm. Since the distance is proportional to the power, the substrate distance should have a certain width. If the device used here is a device that fixes the UV lamp and the substrate, it is not necessary to transfer the substrate. An example of the processing conditions for UV ozone cleaning is given below. Substrate processing atmosphere: Air atmosphere or nitrogen gas atmosphere Cleaning time: About 0.5 to 10 minutes Substrate temperature: 25 to 300 ° C

The film thickness, sheet resistance and surface roughness of the transparent conductive film 107 subjected to oxygen plasma treatment and UV ozone cleaning are as follows: film thickness: 50 to 200 nm Sheet resistance: 5 to 50 Ω · cm / □ Ra): 0.6 to 30 nm. Here, the reason why the sheet resistance becomes low is that the substrate is heated at 200 ° C. or lower in the cleaning step, but ITO is completely crystallized in the heating step and the resistance value thereof is lowered. Further, the surface roughness (Ra) hardly changes even after the plasma treatment and the UV cleaning treatment.

As described above, by performing oxygen plasma treatment and UV ozone cleaning on the transparent conductive film 107, the work function and wettability of the transparent conductive film 107 are improved, and the hole injection efficiency in the pixel electrode 111 is improved. To do.

(1) -3 Pixel Electrode Forming Step In this pixel electrode forming step, the transparent conductive film 107 is etched by using the photolithography technique to form the pixel electrode 111 having a predetermined pattern. As shown in FIG. 5, a photoresist 108 is applied on the transparent conductive film 107, a mask (not shown) is used to transfer a mask pattern corresponding to the pixel electrodes 111 to the photoresist 108, and a mask pattern of this resist is formed. Is used to etch the transparent conductive film 107 to form the pixel electrode 111 having a desired shape. From the above, the film thickness: 50 to 200 nm, the sheet resistance: 5 to 50 Ω · cm / □, the surface roughness (Ra): 0.6
A pixel electrode 111 of ˜30 nm is obtained.

(2) Bank Section Forming Step In the bank section forming step, the bank section 1 is formed at a predetermined position on the substrate 2.
It is a step of forming 12. The bank portion 112 has a structure in which an inorganic bank layer 112a is formed as a first bank layer and an organic bank layer 112b is formed as a second bank layer. The forming method will be described below.

(2) -1 Formation of Inorganic Bank Layer 112a First, as shown in FIG. 6, the inorganic bank layer 112a is formed at a predetermined position on the substrate 2. Inorganic bank layer 112
The position where a is formed is on the second interlayer insulating film 144b and on the pixel electrode 111. The second interlayer insulating film 144
b is formed on the circuit element portion 14 in which thin film transistors, scanning lines, signal lines, etc. are arranged. For the inorganic bank layer 112a, for example, an inorganic film such as SiO ₂ or TiO ₂ can be used as a material. These materials are formed by, for example, a CVD method, a coating method, a sputtering method, a vapor deposition method, or the like. The thickness of the inorganic bank layer 112a is 5
The range of 0 to 200 nm is preferable, and 150 nm is particularly preferable.

The inorganic bank layer 112a has an opening formed by forming an inorganic film on the entire surface of the second interlayer insulating film 144b and the pixel electrode 111, and then patterning the inorganic film by photolithography or the like. The inorganic bank layer 112a is formed. This opening corresponds to the formation position of the electrode surface 111a of the pixel electrode 111, and is formed as a lower opening 112c as shown in FIG. At this time, the inorganic bank layer 112a
Is formed such that a part of the peripheral portion thereof overlaps a part of the peripheral portion of the pixel electrode 111. As shown in FIG. 6, the light emitting region of the light emitting layer 110 is controlled by forming the inorganic bank layer 112a so that a part of the peripheral edge of the pixel electrode 111 and a part of the peripheral edge of the inorganic bank layer 112a overlap. can do.

(2) -2 Formation of Organic Bank Layer 112b Next, as shown in FIG. 7, an organic bank layer 112b as a second bank layer is formed on the inorganic bank layer 112a. For the organic material bank layer 112b, for example, an organic resin having heat resistance and solvent resistance such as acrylic resin or polyimide resin can be used as a material. The organic bank layer 112b is formed by forming an organic resin film on the entire surface of the inorganic bank layer 112a and the pixel electrode 111.
By patterning this organic resin film by a photolithography method or the like, an organic bank layer 112b having an opening is formed. This opening is formed as an upper opening 112d at a position corresponding to the electrode surface 111a and the lower opening 112c during patterning.

Thus, the upper opening 112d formed in the organic bank layer 112b and the inorganic bank layer 112 are formed.
By communicating with the lower opening 112c formed in a, the inorganic bank layer 112a and the organic bank layer 1
An opening 112g that penetrates 12b is formed. In addition,
The organic bank layer 112b has a thickness of 0.1 to 3.5 μm.
Is preferable, and a thickness of about 2 μm is particularly preferable.
The reason why the thickness of the organic bank layer 112b is limited to such a range is as follows.

That is, when the thickness is less than 0.1 μm, the thickness of the organic bank layer 112b becomes smaller than the total thickness of the hole injecting / transporting layer 110a and the light emitting layer 110b which will be described later, and the light emitting layer 110b has an upper opening. This is because there is a risk of overflow from 112d, and the thickness is 3.5μ.
If m is exceeded, the step difference due to the upper opening 112d becomes large, and the step coverage of the cathode 12 in the upper opening 112d cannot be secured. In addition, it is preferable that the thickness of the organic bank layer 112b is 2 μm or more, because the insulation between the cathode 12 and the driving thin film transistor 123 can be improved.

(3) Plasma Treatment Step This plasma treatment step is performed for the purpose of activating the surface of the pixel electrode 111 and further surface-treating the surface of the bank portion 112. In particular, the activation treatment step is performed mainly for the purpose of cleaning the surface of ITO, which is a material forming the pixel electrode 111, and adjusting the work function.
Further, the surface treatment step is performed mainly for the purpose of making the surface of the pixel electrode 111 lyophilic and the surface of the bank portion 112 lyophobic. This plasma processing step, for example,
(3) -1 preheating step, (3) -2 activation treatment step (lyophilic step), (3) -3 lyophobic treatment step (lyophobic step), and (3) -4
It is roughly divided into a cooling process. Note that the number of steps is not limited to such steps, and steps may be reduced and additional steps may be added as necessary.

Here, a plasma processing apparatus used in this plasma processing step will be described with reference to FIG. The plasma processing apparatus 50 includes a preheating processing chamber 5
1, first plasma processing chamber 52, second plasma processing chamber 5
3, a cooling processing chamber 54, and a transfer device 55 that transfers the substrate 2 to each of these processing chambers 51 to 54. The processing chambers 51 to 54 are radially arranged with the transfer device 55 as the center.

First, an outline of a plasma processing step performed using this plasma processing apparatus will be described. The preheating process is performed in the preheating treatment chamber 51 shown in FIG.
Then, the processing chamber 51 heats the substrate 2 transferred from the bank forming process to a predetermined temperature. After the preheating step, the lyophilic step and the lyophobic treatment step are performed. In the preheat treatment chamber 51, the substrate 2 transferred from the bank forming process is heated to a predetermined temperature. After this preheating step, an activation processing step is performed in the first plasma processing chamber 52. In the first plasma processing chamber 52, the transfer device 55
The surface of each of the pixel electrode 111 and the bank portion 112 of the substrate 2 transported from the preheating treatment chamber 51 is subjected to plasma treatment to be lyophilic.

After the activation process, the liquid repellent process is performed in the second plasma processing chamber 53. In the second plasma processing chamber 53, the surface of the bank portion 112 of the substrate 2 that has been lyophilic transferred from the first plasma processing chamber 52 by using the transfer device 55 is subjected to plasma processing to be lyophobic. After the liquid repellent treatment step, the substrate 2 is transported to the cooling treatment chamber 54 and cooled to room temperature. After this cooling step, the transport device 55
Then, the substrate is transported to the next step, which is a hole injection / transport layer forming step.

Hereinafter, each step will be described in detail. (3) -1 Preheating Step The preheating step is a step performed in order to eliminate the temperature variation of the substrate 2 by preheating the substrate 2 in time with the next step. Done. In the processing chamber 51, the substrate 2 including the pixel electrodes 111 and the bank portion 112 is heated to a predetermined temperature.
As a method of heating the substrate 2, for example, a method is used in which a heater is attached to a stage for mounting the substrate 2 arranged in the preheat treatment chamber 51, and the substrate 2 is heated together with the heater by the heater.

In this preheating step, the substrate 2 is heated to a temperature in the range of 70 ° C. to 80 ° C., for example. This temperature range is a processing temperature in the plasma processing step which is the next step, and the substrate 2 is heated in advance in accordance with the next step,
The purpose is to eliminate the temperature variation of the substrate 2. If the pre-heating process is not added, the substrate 2 will be rapidly heated from room temperature to the above temperature, and the temperature will always be changed during the plasma processing process from the process start to the process end. become. Therefore, performing plasma treatment in a state where the substrate temperature changes greatly may lead to non-uniformity of the characteristics of the organic EL element. Therefore, the treatment conditions should be kept constant and pre-heating to obtain uniform characteristics. To do.

This preheating temperature is subjected to the subsequent steps, that is, the lyophilic treatment is performed with the substrate 2 placed on the sample stage in the first plasma processing apparatus 52 and the sample stage in the second plasma processing apparatus 53. When the lyophobic treatment is performed with the substrate 2 placed thereon, it is preferable that the temperature of the sample stage 56, which continuously performs the lyophilic treatment step and the lyophobic treatment step as shown in FIG. . Therefore,
The substrate 2 is preliminarily provided with, for example, the first and second plasma processing devices 5
By preheating to a temperature of the sample stage 56, which is movable between 2, 53, for example, 70 to 80 ° C.,
Even when plasma processing is continuously performed on many substrates,
The plasma processing conditions immediately after the start of processing and immediately before the end of processing can be made almost constant. Thereby, the surface treatment conditions of the substrate 2 can be made the same, the wettability of the bank portion 112 with respect to the composition can be made uniform, and an organic EL device having a certain quality can be manufactured. Further, by preheating the substrate 2 in advance, it is possible to shorten the processing time in the subsequent plasma processing.

(3) -2 Activation Treatment Step The activation treatment step includes adjustment and control of the work function of the pixel electrode 111, cleaning of its surface, and lyophilic treatment of its surface. As a lyophilic process, O ₂ plasma treatment using oxygen as a treatment gas is performed in the atmosphere. FIG. 9 schematically shows this O ₂ plasma treatment. As shown in FIG. 9, the substrate 2 including the bank portion 112 is placed on the sample stage 56 having a built-in heater, and the plasma discharge electrode 5 is placed.
7 is arranged facing the upper surface of the substrate 2 with a gap distance of about 0.5 to 2 mm, the heater 2 in the sample stage 56 is energized, and the substrate 2 on the sample stage 56 is energized.
While heating, the sample stage 56 is transported in the direction of the arrow in the drawing at a predetermined transport speed, and during this transport, the plasma discharge electrode 57 irradiates the substrate 2 with oxygen in a plasma state.

The conditions of this O ₂ plasma treatment are, for example,
Plasma power: 100 to 800 kW, oxygen gas flow rate:
50-100 ml / min, substrate transfer speed: 0.5-10 m
m / sec, substrate temperature: 70 to 90 ° C.
The heating by the sample stage 56 is performed mainly for keeping the temperature of the preheated substrate 2. By this O ₂ plasma treatment, as shown in FIG.
Electrode surface 111a, the first laminated portion 112e of the inorganic bank layer 112a, and the upper opening portion 1 of the organic bank layer 112b.
The side surface of 12d and the upper surface 112f are lyophilic.
By this lyophilic treatment, lyophilicity is imparted by introducing a hydroxyl group into each of these surfaces. In FIG. 10, the portion that has been subjected to the lyophilic treatment is indicated by a one-dot chain line.

(3) -3 Liquid-repellent treatment step Next, in the second plasma treatment chamber 53, a plasma treatment using tetrafluoromethane (tetrafluoromethane: CF ₄ ) as a treatment gas in the atmosphere is performed as a liquid-repellent treatment step. Processing (CF ₄ plasma processing) is performed. The internal structure of the second plasma processing chamber 53 is the same as the internal structure of the first plasma processing chamber 52 shown in FIG. That is, while the substrate 2 is being heated by the sample stage, the substrate 2 is transported at a predetermined transport speed together with the sample stage, and during this period, the substrate 2 is irradiated with tetrafluoromethane (tetrafluoromethane: CF ₄ ) in a plasma state. .

The conditions for the CF ₄ plasma treatment are, for example, plasma power: 100 to 800 kW, CF ₄ gas flow rate:
50 to 100 ml / min, substrate transfer speed: 0.5 to 1
The condition is 0 mm / sec and the substrate temperature is 70 to 90 ° C. Note that the heating by the heating stage is performed mainly for keeping the temperature of the preheated substrate 2 as in the case of the first plasma processing chamber 52. The processing gas is not limited to tetrafluoromethane (tetrafluoromethane), and other fluorocarbon-based gas can be used.

By this CF ₄ plasma treatment, as shown in FIG. 11, the side surface of the upper opening 112d and the upper surface 112f of the organic bank layer are subjected to liquid repellent treatment. By this liquid repellent treatment, a fluorine group is introduced into each of these surfaces to impart liquid repellency. In FIG. 11, the liquid-repellent region is indicated by a chain double-dashed line. Organic substances such as acrylic resin and polyimide resin, which form the organic bank layer 112b, can be easily rendered lyophobic by being irradiated with fluorocarbon in a plasma state. In addition, the pretreatment with O ₂ plasma is more likely to be fluorinated, which is particularly effective in this embodiment. It should be noted that the electrode surface 111a of the pixel electrode 111 and the first stacked portion 11 of the inorganic bank layer 112a.
2e is also slightly affected by this CF ₄ plasma treatment,
Less likely to affect wettability. In FIG. 11, the region showing lyophilicity is indicated by a one-dot chain line.

(3) -4 Cooling Step Next, as a cooling step, the cooling processing chamber 54 is used to cool the substrate 2 heated for the plasma processing to a control temperature. This is a process performed for cooling to the control temperature of the inkjet process (functional layer forming process) which is the subsequent process. The cooling processing chamber 54 has a plate for disposing the substrate 2, and the plate has a structure in which a water cooling device is incorporated so as to cool the substrate 2. Further, by cooling the substrate 2 after the plasma treatment to room temperature or a predetermined temperature (for example, a control temperature at which the inkjet process is performed), the temperature of the substrate 2 becomes constant in the next hole injection / transport layer forming process, The next step can be performed at a uniform temperature at which the temperature of the substrate 2 does not change. Therefore, by adding such a cooling step, it is possible to uniformly form the material discharged by the discharging means such as an inkjet method. For example, when ejecting the first composition containing the material for forming the hole injecting / transporting layer, the first composition can be ejected continuously in a constant volume. Can be formed uniformly.

In the above plasma processing step, the organic bank layer 112b and the inorganic bank layer 112a made of different materials are used.
On the other hand, by sequentially performing the O ₂ plasma treatment and the CF ₄ plasma treatment, the lyophilic region and the lyophobic region can be easily provided in the bank portion 112. The plasma processing apparatus used in the plasma processing step is not limited to that shown in FIG. 8, and a plasma processing apparatus 60 as shown in FIG. 12, for example, may be used. The plasma processing apparatus 60 shown in FIG. 12 includes a preheating processing chamber 61, a first plasma processing chamber 62, a second plasma processing chamber 63, and a cooling processing chamber 64.
And a transfer device 65 that transfers the substrate 2 to each of the processing chambers 61 to 64. The processing chambers 61 to 64 are arranged on both sides of the transfer device 65 in the transport direction (both sides in the arrow direction in the drawing). It will be.

In this plasma processing apparatus 60, as in the plasma processing apparatus 50 shown in FIG. 8, the substrate 2 transferred from the bank portion forming step is processed by the preheating processing chamber 61, the first,
After being sequentially transferred to the second plasma processing chambers 62 and 63 and the cooling processing chamber 64 and subjected to the same processing as described above in each processing chamber, the substrate 2 is transferred to the next hole injection / transport layer forming step. Further, the plasma treatment may be performed under vacuum or reduced pressure instead of atmospheric pressure.

(4) Hole Injection / Transport Layer Forming Step Next, as a hole injection / transport layer forming step, a hole injection / transport layer is formed on the electrode (here, the pixel electrode 111).
In the hole injecting / transporting layer forming step, the hole injecting / transporting layer is formed by using, for example, an ink jet device.
The first composition (composition) containing the material for forming the transport layer is applied to the electrode surface 1
It discharges on 11a. After that, a drying process and a heat treatment are performed to form the hole injection / transport layer 110a on the pixel electrode 111 and the inorganic bank layer 112a. Note that hole injection /
Here, the inorganic bank layer 112a on which the transport layer 110a is formed is referred to as a first laminated portion 112e.

It is preferable that the subsequent steps including this hole injection / transport layer forming step are performed in an atmosphere free of water and oxygen. For example, it is preferably performed in an inert gas atmosphere such as a nitrogen atmosphere or an argon atmosphere. The hole injection / transport layer 110a may not be formed on the first stacked unit 112e. That is, hole injection / only on the pixel electrode 111.
There is also a form in which the transport layer is formed. The manufacturing method by inkjet is as follows.

A head H as shown in FIG. 13 can be exemplified as an example of an ink jet head which is preferably used in the method of manufacturing the organic EL device of this embodiment. This head H has a plurality of ink jet heads H1 as shown in FIG.
And a support substrate H7 for supporting these inkjet heads H1. Further, regarding the disposition of the substrate and the head H, it is preferable to dispose as shown in FIG. In the inkjet device shown in FIG. 14, reference numeral 1115 is a stage on which the base 2 is placed,
Reference numeral 1116 is a guide rail that guides the stage 1115 in the x-axis direction (main scanning direction) in the drawing. Head H
Can be moved in the y-axis direction (sub-scanning direction) in the drawing by the guide rail 1113 via the support member 1111. Further, the head H can be rotated in the θ-axis direction in the drawing. The head H1 can be tilted at a predetermined angle with respect to the main scanning direction.

The substrate 2 shown in FIG. 14 has a structure in which a plurality of chips are arranged on a mother substrate. That is, one chip area corresponds to one display device. Here, three display areas 2a are formed, but the number is not limited to this. For example, when the composition is applied to the display area 2a on the left side of the substrate 2, the head H is moved to the left side in the drawing via the guide rail 1113, and the base 2 is moved to the left side in the drawing via the guide rail 1116. It is moved to the upper side, and coating is performed while scanning the substrate 2. Next, the head H is moved to the right side in the drawing to apply the composition to the display region 2a at the center of the substrate. The same applies to the display area 2a at the right end. The head H shown in FIG. 13 and the inkjet device shown in FIG. 14 may be used not only in the hole injecting / transporting layer forming step but also in the light emitting layer forming step.

As the first composition used here, for example, a polythiophene derivative such as polyethylenedioxythiophene (PEDOT) and polystyrene sulfonic acid (P
A composition in which a mixture such as SS) is dissolved in a polar solvent can be used. Examples of polar solvents include isopropyl alcohol (IPA), n-butyl alcohol, and γ.
-Butyrolactone, N-methylpyrrolidone (NMP),
Examples thereof include 1,3-dimethyl-2-imidazolidinone (DMI) and its derivatives, glycols such as carbitol acetate and butyl carbitol acetate.

As a more specific composition of the first composition,
PEDIT / PSS mixture (PEDIT / PSS = 1:
20): 12.52% by weight, PSS: 1.44% by weight,
IPA: 10% by weight, NMP: 27.48% by weight, DM
I: 50 weight% can be illustrated. The viscosity of the first composition is preferably about 2 to 20 Ps, particularly 4 to 15 cP.
s is good. By using the above first composition,
The discharge nozzle H2 can be stably discharged without clogging. The material for forming the hole injecting / transporting layer is red (R),
The same material may be used for each of the green (G) and blue (B) light emitting layers 110b1 to 110b3, or may be changed for each light emitting layer.

As shown in FIG. 15, the ejected droplet 110c of the first composition eventually spreads on the lyophilic-treated electrode surface 111a and the first laminated portion 112e, and the lower and upper openings are formed. 112c and 112d are filled. Even if the droplets 110c of the first composition are ejected from the predetermined ejection position onto the upper surface 112f, the upper surface 112f is not wetted by the first composition droplets 110c and is repelled by the first composition. Droplet 110c is at the bottom, top opening 112c, 1
Roll into 12d.

The total amount of the first composition discharged onto the electrode surface 111a is determined by the size of the lower and upper openings 112c and 112d, the thickness of the hole injecting / transporting layer to be formed, and the amount of the first composition. It is determined by the concentration of the hole injection / transport layer forming material.

Then, a drying process as shown in FIG. 16 is performed. By performing a drying step, the first composition after discharge is subjected to a drying treatment to evaporate the polar solvent contained in the first composition,
A hole injection / transport layer 110a is formed. When the drying process is performed, evaporation of the polar solvent contained in the first composition droplets 110c is mainly caused by the inorganic bank layer 112a and the organic bank layer 1.
It occurs in the vicinity of 12b, and the hole injection / transport layer forming material is concentrated and deposited along with the evaporation of the polar solvent. As a result, as shown in FIG. 17, the peripheral edge portion 110a2 made of the hole injection / transport layer forming material is formed on the first laminated portion 112e. The peripheral portion 110a2 is formed by the upper opening 112.
It is in close contact with the wall surface (organic bank layer 112b) of d,
The thickness is thin on the side close to the electrode surface 111a,
It is thicker on the side away from 11a, that is, on the side closer to the organic bank layer 112b.

At the same time, the drying process causes evaporation of the polar solvent on the electrode surface 111a, thereby forming a flat portion 110a1 made of the hole injection / transport layer forming material on the electrode surface 111a. Since the evaporation rate of the polar solvent is almost uniform on the electrode surface 111a, hole injection /
The material for forming the transport layer is uniformly concentrated on the electrode surface 111a, so that the flat portion 110a having a uniform thickness is formed. In this way, the peripheral portion 110a2 and the flat portion 11 are
A hole injection / transport layer 110a of 0a1 is formed. The electrode surface 1 is not formed on the peripheral portion 110a2.
The hole injection / transport layer may be formed only on 11a.

The above-mentioned drying treatment is performed, for example, in a nitrogen atmosphere at room temperature at a pressure of, for example, 133.3 Pa (1 Torr).
r). If the pressure is too low, the first composition drop 1
This is not preferable because 10c will boil. Further, if the temperature is higher than room temperature, the evaporation rate of the polar solvent is increased, and it is not possible to form a flat film. After the drying treatment, it is preferable to remove the polar solvent and water remaining in the hole injecting / transporting layer 110a by performing a heat treatment of heating at 200 ° C. for about 10 minutes in nitrogen, preferably in vacuum.

(5) Light-Emitting Layer Forming Step This light-emitting layer forming step is composed of a light-emitting layer forming material discharging step and a drying step. First, a light emitting layer forming material discharging step is performed. By the inkjet method (droplet ejection method),
The second composition containing the light emitting layer forming material is used as the hole injecting / transporting layer 1
After being discharged onto 10a, it is dried to form a light emitting layer 110b on the hole injection / transport layer 110a. In FIG.
An outline of the ink jetting method will be described. As shown in FIG. 17, the inkjet head H5 and the substrate 2 are moved relative to each other, and a second color containing a light emitting layer forming material of each color (for example, blue (B) here) is discharged from the discharge nozzle H6 formed in the inkjet head. The composition is ejected.

At the time of discharge, the lower and upper openings 112
The second composition is ejected while the ejection nozzle is opposed to the hole injection / transport layer 110a located in c and 112d, and the inkjet head H5 and the substrate 2 are relatively moved. The amount of liquid ejected from the ejection nozzle H6 is controlled such that the amount of liquid per droplet is controlled. A liquid (second composition droplet 110e) whose liquid amount is controlled in this way is discharged from the discharge nozzle,
The second composition droplet 110e is used as the hole injection / transport layer 110a.
Dispense up. In the light emitting layer forming step, like the hole injecting / transporting layer forming step, the first droplet is discharged so as to hit the bank portion 112. The second droplet may be ejected so as to overlap the first droplet, or may be ejected at intervals. Further, one pixel area may be divided into two scans.

That is, as shown in FIG. 17, the first droplets of the second composition discharged to one opening 112g are:
The ejection is performed so as to contact the inclined wall surface 112h of the organic bank layer 112b. Since the wall surface 112h of the organic bank layer 112b has been treated to be liquid repellent in the previous liquid repellent process, the ejected droplets are immediately repelled although they come into contact with the wall surface 112h, and roll on the wall surface 112h to inject holes. / Rolls down on the transport layer 110a. It should be noted that this first droplet is the wall surface 112h of the organic bank layer 112b.
It is sufficient to contact at least a part of the above, and the ejection may be performed so as to come into contact with the upper surface 112f of the organic bank layer at the same time as the wall surface 112h.

Subsequently, the second and subsequent droplets are ejected at intervals such that they do not overlap with the immediately preceding droplet, as in FIG. That is, it is preferable that the interval D at the time of dropping each droplet be set wider than the diameter d of each droplet (D> d). In this case, since the number of droplets that can be ejected in one scan is limited, in order to form the light emitting layer 112b having a sufficient film thickness,
It is preferable that the inkjet head H5 scans one pixel area A multiple times.

Further, as in FIG. 17, the second and subsequent droplets may be ejected at intervals such that they overlap the immediately preceding droplet. That is, the interval D at the time of dropping each droplet is defined as the diameter d of each droplet.
It may be narrower (D <d). In this case, since the number of droplets that can be ejected in one scan is not limited, one scan of the inkjet head H5 for one pixel region A is performed in order to form the light emitting layer 112b having a sufficient film thickness. Or multiple times. When the inkjet head H5 is scanned a plurality of times, it is preferable to shift the inkjet head H5 in the sub-scanning direction for each scanning and switch from a specific nozzle to another nozzle to perform ejection, as described above. When the plurality of nozzles are used to perform ejection to one pixel area A as described above, the film thickness of the light emitting layer 112b formed in each pixel area A is changed by the effect of error diffusion as described above. Can be uniform.

Particularly, when the scanning of the ink jet head H5 with respect to one pixel area A is performed twice,
The scanning directions of the second scanning and the second scanning may be opposite to each other or may be the same. When the scanning directions of the first and second scans are opposite to each other, the first composition may be discharged to a half region of the pixel region A in the first scan and the remaining half region may be discharged in the second scan. Good. Further, the second scanning can be performed so that the area formed by the first scanning is filled. Further, when the scanning directions of the first and second scans are the same, the droplets are ejected at intervals such that the droplets do not come into contact with each other in the first scan, and the droplets are ejected in the second scan. It is only necessary to discharge so as to fill the area. Of course, it is also possible to divide one pixel region into two regions for ejection.

Examples of the material for forming the light emitting layer include polyfluorene derivatives, polyphenylene derivatives, polyvinylcarbazole, polythiophene derivatives, perylene dyes, coumarin dyes, rhodamine dyes, or the above polymer materials such as rubrene, perylene, 9 , 10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6, quinacridone, etc. can be used by doping.

As the non-polar solvent, the hole injecting / transporting layer 1 is used.
Those which are insoluble in 10a are preferable, and for example, cyclohexylbenzene, dihydrobenzofuran, trimethylbenzene, tetramethylbenzene and the like can be used. By using such a non-polar solvent for the second composition of the light emitting layer 110b, the second composition can be applied without redissolving the hole injection / transport layer 110a.

As shown in FIG. 17, the discharged second composition 110e spreads over the hole injection / transport layer 110a and fills the lower and upper openings 112c and 112d.
On the other hand, on the liquid-repellent treated upper surface 112f, the first composition droplet 110e deviates from the predetermined ejection position, and the upper surface 112f.
Even if the second composition droplet 110e is ejected onto the upper surface 112f, the upper surface 112f does not get wet with the second composition droplet 110e.
Rolls into the lower and upper openings 112c and 112d.

The amount of the second composition discharged onto each of the hole injecting / transporting layers 110a is set to the lower and upper openings 112c and 112d.
, The thickness of the light emitting layer 110b to be formed, the concentration of the light emitting layer material in the second composition, and the like. Further, the second composition 110e may be discharged onto the same hole injection / transport layer 110a not only once but also several times. In this case, the amount of the second composition in each time may be the same, or the liquid amount of the second composition may be changed in each time. Further, the second composition may be discharged and arranged not only at the same position in the hole injection / transport layer 110a but also at different positions in the hole injection / transport layer 110a each time.

Next, after the second composition has been discharged to a predetermined position, the discharged second composition droplet 110e is dried to form the light emitting layer 110b3. That is, the non-polar solvent contained in the second composition is evaporated by drying, and the blue (B) light emitting layer 110b3 as shown in FIG. 18 is formed. Although only one light emitting layer that emits blue light is shown in FIG. 18, the light emitting elements are originally formed in a matrix and are not shown in the figure, as is clear from FIG. 1 and other drawings. A large number of light emitting layers (corresponding to blue) are formed.

Subsequently, as shown in FIG. 19, the same steps as those for the blue (B) light emitting layer 110b3 described above are used.
The red (R) light emitting layer 110b1 is formed, and finally the green (G) light emitting layer 110b2 is formed. The light emitting layer 11
The formation order of 0b is not limited to the above-mentioned order, and may be formed in any order. For example, it is possible to determine the order of formation according to the light emitting layer forming material.

The drying conditions for the second composition of the light emitting layer are as follows:
In the case of blue 110b3, for example, in a nitrogen atmosphere, at room temperature, the pressure is about 133.3 Pa (1 Torr), and the pressure is 5-1.
The condition is 0 minutes. If the pressure is too low, the second composition will bump, which is not preferable. Further, if the temperature is set to room temperature or higher, the evaporation rate of the nonpolar solvent is increased, and a large amount of the light emitting layer forming material adheres to the wall surface of the upper opening 112d, which is not preferable. Further, in the case of the green light emitting layer 110b2 and the red light emitting layer b1, it is preferable to dry quickly because of the large number of components of the light emitting layer forming material, for example, 40 ° C.
It is preferable that the condition that the nitrogen is sprayed for 5 to 10 minutes is used. Examples of other drying means include a far infrared irradiation method and a high temperature nitrogen gas spraying method. In this way, the hole injection / transport layer 110a and the light emitting layer 110b are formed on the pixel electrode 111.

(5) Counter Electrode (Cathode) Forming Step In the counter electrode forming step, as shown in FIG.
0b and the organic bank layer 112b, the cathode 12 (counter electrode) is formed. The cathode 12 may be formed by stacking a plurality of materials. For example, it is preferable to form a material having a small work function on the side close to the light emitting layer, and for example, Ca, Ba or the like can be used, and depending on the material, it is better to form LiF or the like thinly in the lower layer. There is also. Further, a material having a work function higher than that of the lower side, for example, Al can be used for the upper side (sealing side). These cathodes 12 are preferably formed by, for example, a vapor deposition method, a sputtering method, a CVD method, or the like, and particularly preferably formed by a vapor deposition method because damage to the light emitting layer 110b due to heat can be prevented. Further, lithium fluoride may be formed only on the light emitting layer 110b, and can be formed corresponding to a predetermined color. For example, it may be formed only on the blue (B) light emitting layer 110b3. In this case, the other red (R) light emitting layer and the green (G) light emitting layer 110b1 and 110b2 are in contact with the upper cathode layer 12b made of calcium.

Further, on the cathode 12, it is preferable to use an Al film, an Ag film or the like formed by a vapor deposition method, a sputtering method, a CVD method or the like. The thickness is, for example, 100
To 1000 nm is preferable, and 200 to 500 is particularly preferable.
nm is preferable. A protective layer such as SiO ₂ or SiN _x may be provided on the cathode 12 to prevent oxidation.

(7) Sealing Step In the sealing step, the substrate 2 on which the light emitting element is formed and the sealing substrate 3
This is a step of sealing b with the sealing resin 3a. For example, the sealing resin 3a made of a thermosetting resin or an ultraviolet curing resin is applied to the entire surface of the substrate 2, and the sealing substrate 3b is laminated on the sealing resin 3a. Through this step, the sealing portion 3 is formed on the substrate 2. The sealing step is preferably performed in an inert gas atmosphere such as nitrogen, argon or helium. If it is performed in the atmosphere, when defects such as pinholes occur in the cathode 12, water, oxygen, etc. may enter the cathode 12 from the defective portions and the cathode 12 may be oxidized, which is not preferable. Further, the cathode 12 is connected to the wiring 5a of the substrate 5 illustrated in FIG.
And the wiring of the circuit element portion 14 is connected to the drive IC 6, the organic EL device 1 of the present embodiment is connected.
Is obtained.

According to the method of manufacturing the organic EL device of the present embodiment, the surface roughness of the pixel electrode 111 is set within the range in which the electrical characteristics of the light emitting layer 110 do not change.
It is possible to prevent the deterioration of the electrical characteristics of the light emitting layer 110 due to the surface roughness of 11, and to stabilize the initial characteristics and the life characteristics of the organic EL device. Therefore,
It is possible to provide an organic EL device having stable initial characteristics and life characteristics.

[Second Embodiment] Specific examples of electronic equipment including the organic EL device of the first embodiment will be described below. FIG. 21A is a perspective view showing an example of a mobile phone. In FIG. 21A, reference numeral 600 indicates a mobile phone main body, and reference numeral 601 indicates a display unit using the organic EL display device. FIG. 21B shows a word processor,
It is a perspective view showing an example of a portable information processing device such as a personal computer. In FIG. 21B, reference numeral 700 is an information processing apparatus, reference numeral 701 is an input unit such as a keyboard, and reference numeral 7 is shown.
Reference numeral 02 denotes a display unit using the above-mentioned organic EL display device, reference numeral 7
Reference numeral 03 denotes an information processing apparatus main body. FIG. 21 (c)
FIG. 3 is a perspective view showing an example of a wrist watch type electronic device. In FIG. 21C, reference numeral 800 indicates the timepiece main body, and reference numeral 801 indicates the display unit using the organic EL display device.

Each of the electronic devices shown in FIGS. 21A to 21C is provided with a display section using the organic EL display device of the first embodiment, and the first embodiment described above is used. Since the organic EL display device has the characteristics of the organic EL display device of the embodiment, the electronic device has high brightness and excellent display quality. In order to manufacture these electronic devices, the organic EL display device 1 including the driving IC 6 (driving circuit) as shown in FIG. 2 is configured similarly to the first embodiment, and the organic EL display device 1 is manufactured. Is incorporated into a mobile phone, a portable information processing device, or a wristwatch type electronic device.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made without departing from the spirit of the present invention. FIG. 22
FIG. 3 is a cross-sectional view showing another example of an organic EL device according to the present invention, which is applied to the substrate 2, the display element 10 formed on the substrate 2, and the entire surface of the display element 10. The sealing resin 3a and the sealing substrate 3b provided on the sealing resin 3a are provided. The substrate 2, the display element 10, the sealing resin 3a, and the sealing substrate 3b are the same as the substrate 2, the display element 10, the sealing material 3, and the sealing substrate 4 according to the first embodiment. The display element 10 is mainly composed of a light emitting element section 11 and a cathode 12 formed on the light emitting element section 11. According to this organic EL device, the invasion of water and oxygen is effectively prevented to prevent the cathode 12 or the light emitting layer from being oxidized, corroded, etc.
Higher brightness and longer life of the device can be achieved.

FIG. 23 is a cross-sectional view showing another example of the organic EL device according to the present invention. This organic EL device has a structure in which a protective layer 714 is formed between the sealing material 3 and the cathode 12. Is. The protective layer 714 is made of SiO ₂ , Si ₃ N ₄ or the like, and has a thickness in the range of 100 to 200 nm. The protective layer 714 is used for the cathode 12 and the light emitting element section 1.
Oxidation of a light emitting layer (not shown) formed in the cathode 12 or the light emitting element portion 11 while preventing the invasion of water or oxygen into 1.
Prevents corrosion. According to the above-mentioned organic EL device, the invasion of water and oxygen is effectively prevented and the cathode 12 or the light emitting layer is prevented from being oxidized and corroded, so that the organic EL display device has high brightness and long life. be able to.

Further, in the first embodiment, R,
The case where the G and B light emitting layers 110b are arranged in stripes has been described, but the present invention is not limited to this, and various arrangement structures may be adopted. For example, in addition to the stripe arrangement shown in FIG. 24A, a mosaic arrangement shown in FIG. 24B or a delta arrangement shown in FIG. 24C can be used.

[0108]

As described above in detail, according to the electro-optical device of the present invention, since at least one electrode of the pair of electrodes has the unevenness on the surface on the side of the light emitting layer, one of the electrodes has It is possible to prevent the deterioration of the electrical characteristics of the light emitting layer due to the surface roughness of the electrodes, and to stabilize the initial characteristics and the life characteristics of the electro-optical device. Therefore,
It is possible to easily provide an electro-optical device having stable initial characteristics and life characteristics.

According to the method of manufacturing an electro-optical device of the present invention, since at least one electrode of the pair of electrodes is formed so as to have irregularities on the light emitting layer side, the flatness of the one electrode can be improved. The electrical characteristics of the light emitting layer can be improved without damaging the light emitting layer. Therefore, an electro-optical device having stable initial characteristics and life characteristics can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a wiring structure of an organic EL device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the organic EL device according to the first embodiment of the present invention, in which (a) is a plan view of the organic EL display device;
(B) is sectional drawing which follows the AA line of (a).

FIG. 3 is a cross-sectional view showing a main part of the organic EL device according to the first embodiment of the present invention.

FIG. 4 is a process chart showing the manufacturing method of the organic EL device according to the first embodiment of the present invention.

FIG. 5 is a process chart showing the manufacturing method of the organic EL device according to the first embodiment of the present invention.

FIG. 6 is a process chart showing the manufacturing method of the organic EL device according to the first embodiment of the present invention.

FIG. 7 is a process chart showing the manufacturing method of the organic EL device according to the first embodiment of the present invention.

FIG. 8 is a schematic view showing an example of a plasma processing apparatus used when manufacturing the organic EL device according to the first embodiment of the present invention.

9 is a schematic diagram showing an internal structure of a first plasma processing chamber of the plasma processing apparatus shown in FIG.

FIG. 10 is a process chart showing the method of manufacturing the organic EL device according to the first embodiment of the invention.

FIG. 11 is a process chart showing the method of manufacturing the organic EL device according to the first embodiment of the invention.

FIG. 12 is a schematic view showing another example of the plasma processing apparatus used when manufacturing the organic EL device according to the first embodiment of the present invention.

FIG. 13 is a plan view showing an inkjet head used when manufacturing the organic EL device according to the first embodiment of the present invention.

FIG. 14 is a plan view showing an inkjet device used when manufacturing the organic EL device according to the first embodiment of the present invention.

FIG. 15 is a process chart showing the manufacturing method of the organic EL device according to the first embodiment of the invention.

FIG. 16 is a process diagram showing the manufacturing method of the organic EL device according to the first embodiment of the invention.

FIG. 17 is a process chart showing the method of manufacturing the organic EL device according to the first embodiment of the invention.

FIG. 18 is a process chart showing the method of manufacturing the organic EL device according to the first embodiment of the invention.

FIG. 19 is a process chart showing the method of manufacturing the organic EL device according to the first embodiment of the invention.

FIG. 20 is a process drawing that shows the manufacturing method of the organic EL device according to the first embodiment of the invention.

FIG. 21 is a perspective view showing an electronic device according to a second embodiment of the present invention.

FIG. 22 is a cross-sectional view showing another example of an organic EL device according to the present invention.

FIG. 23 is a cross-sectional view showing another example of an organic EL device according to the present invention.

FIG. 24 is another example of an organic EL according to the present invention.
It is sectional drawing which shows an apparatus.

[Explanation of symbols]

1 Display device 2 substrates 2a display area 2b Non-display area 3 Sealing part 6a Drive IC (drive circuit) 10 Display element 11 Light emitting element section 12 Cathode ((Counter electrode) 110 functional layers 110a Hole injection / transport layer 110a1 flat part 110a2 peripheral part 110b light emitting layer 111 pixel electrode 111a electrode surface 112 Bank Department 112a Inorganic bank layer 112b Organic bank layer 112c Lower opening 112d Upper opening 112e upper surface 112f upper surface 112g opening A pixel area

Claims (8)

[Claims] 1. An electro-optical device comprising a light-emitting element having a light-emitting layer between a pair of electrodes formed on a substrate, wherein at least one of the pair of electrodes has an uneven surface on the light-emitting layer side. An electro-optical device characterized by: 2. The electro-optical device according to claim 1, wherein the light emitting layer is made of an organic polymer. 3. The electro-optical device according to claim 1, wherein the one electrode is made of indium tin oxide or tin oxide. 4. The surface roughness of the surface having the irregularities is 0.5 to 50 nm.
Alternatively, the electro-optical device described in 3. 5. A method of manufacturing an electro-optical device comprising a light-emitting element having a light-emitting layer between a pair of electrodes formed on one surface of a substrate, wherein the pair of light-emitting layers has irregularities on the light-emitting layer side. At least one of the electrodes is formed. 6. The electrical treatment according to claim 5, wherein after the film formation of the one electrode, the one electrode is subjected to a surface treatment so that the surface roughness does not change within a predetermined range. Optical device manufacturing method. 7. The method of manufacturing an electro-optical device according to claim 6, wherein the surface treatment is one or two selected from oxygen plasma treatment and ultraviolet treatment. 8. An electronic apparatus comprising the electro-optical device according to claim 1. Description: