JP4156431B2 - Light emitting device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light-emitting device using a light-emitting element in which fluorescence or phosphorescence is obtained by applying an electric field to an element in which a film containing an organic compound (hereinafter referred to as an “organic compound layer”) is provided between a pair of electrodes. It relates to a manufacturing method thereof. Note that a light-emitting device in this specification refers to an image display device, a light-emitting device, or a light source (including a lighting device). Also, a module in which a connector such as an FPC (Flexible printed circuit) or TAB (Tape Automated Bonding) tape or TCP (Tape Carrier Package) is attached to the light emitting device, or a module in which a printed wiring board is provided at the end of the TAB tape or TCP In addition, a module in which an IC (integrated circuit) is directly mounted on a light emitting element by a COG (Chip On Glass) method is also included in the light emitting device.
[0002]
[Prior art]
A light-emitting element using an organic compound having characteristics such as thin and light weight, high-speed response, and direct current low-voltage driving as a light emitter is expected to be applied to a next-generation flat panel display. In particular, a display device in which light emitting elements are arranged in a matrix is considered to be superior to a conventional liquid crystal display device in that it has a wide viewing angle and excellent visibility.
[0003]
The light-emitting mechanism of the light-emitting element recombines electrons injected from the cathode and holes injected from the anode at the emission center in the organic compound layer by applying a voltage with the organic compound layer sandwiched between a pair of electrodes. Thus, it is said that molecular excitons are formed, and when the molecular excitons return to the ground state, energy is emitted and light is emitted. Singlet excitation and triplet excitation are known as excited states, and light emission is considered to be possible through either excited state.
[0004]
For a light-emitting device formed by arranging such light-emitting elements in a matrix, driving methods such as passive matrix driving (simple matrix type) and active matrix driving (active matrix type) can be used. However, when the pixel density increases, the active matrix type in which a switch is provided for each pixel (or one dot) is considered to be advantageous because it can be driven at a lower voltage.
[0005]
In addition, organic compounds that can be said to be the center of the light-emitting element, ie, the organic compound layer (specifically, the light-emitting layer), are researched on low-molecular materials and high-molecular (polymer-based) materials. Attention has been focused on polymer materials that are easier to handle and have higher heat resistance.
[0006]
Further, in an active matrix light emitting device so far, an electrode electrically connected to a TFT on a substrate is formed as an anode, an organic compound layer is formed on the anode, and a cathode is formed on the organic compound layer. It has a structure in which a light-emitting element is included and light generated in the organic compound layer is extracted from the anode, which is a transparent electrode, toward the TFT.
[0007]
However, in this structure, when the resolution is improved, there is a problem that the aperture ratio is limited by the arrangement of TFTs and wirings in the pixel portion.
[0008]
[Problems to be solved by the invention]
Therefore, in the present invention, an electrode on the TFT side electrically connected to the TFT on the substrate is formed as an anode, a layer containing an organic compound is formed on the anode, and a transparent electrode is formed on the layer containing the organic compound. An active matrix light-emitting device having a light-emitting element having a structure in which a cathode is formed (hereinafter referred to as a top emission structure) is manufactured.
[0009]
Compared with the bottom emission structure, the top emission structure can reduce the number of material layers through which light emitted from a layer containing an organic compound passes, and can suppress stray light between material layers having different refractive indexes.
[0010]
Further, not all of the light generated in the organic compound layer is extracted from the cathode, which is a transparent electrode, toward the TFT. For example, light is emitted in the lateral direction (direction parallel to the substrate surface). Since the light emitted in the lateral direction is not extracted, it is lost. In view of the above, an object of the present invention is to provide a light-emitting device having a structure that increases the amount of light emitted in one direction in a light-emitting element, and a manufacturing method thereof.
[0011]
Further, in the top emission structure, there arises a problem that the film resistance of the transparent electrode is increased. In particular, when the film thickness of the transparent electrode is reduced, the film resistance is further increased. When the film resistance of the transparent electrode serving as the anode or the cathode becomes high, the in-plane potential distribution becomes non-uniform due to the voltage drop, resulting in a problem that the luminance of the light emitting element varies. Accordingly, an object of the present invention is to provide a light emitting device having a structure in which the film resistance of a transparent electrode in a light emitting element is reduced, and a method for manufacturing the same. Then, it is an object to provide an electric appliance using such a light-emitting device as a display portion.
[0012]
[Means for Solving the Problems]
The present invention forms a first electrode composed of a stack of metal layers, forms an insulator (called a bank or a partition) covering an end of the first electrode, and then self-aligns using the insulator as a mask. Etching is performed to etch a portion of the insulator and thinly etch the central portion of the first electrode to form a step at the end. By this etching, the central portion of the first electrode is thin and flat, and the end portion of the first electrode covered with the insulator is thick, that is, a concave shape. Then, a layer containing an organic compound and a second electrode are formed over the first electrode to complete the light-emitting element.
[0013]
The present invention increases the amount of light emitted in one direction (direction passing through the second electrode) by reflecting or condensing the light emitted in the lateral direction on the slope formed at the step portion of the first electrode. It is.
[0014]
Therefore, the sloped portion is preferably a material mainly composed of a metal that reflects light, such as aluminum or silver, and the central portion in contact with the layer containing an organic compound is an anode material having a high work function, or It is preferable to use a cathode material having a small work function.
[0015]
The configuration 1 of the invention disclosed in this specification is:
A first electrode connected to a thin film transistor over a substrate having an insulating surface;
An insulator covering an end of the first electrode;
A light-emitting element having a layer containing an organic compound in contact with the first electrode and a second electrode in contact with the layer,
The first electrode has an inclined surface toward the center of the first electrode at the end of the first electrode, and the inclined surface reflects light emitted from the layer containing the organic compound. A light emitting device characterized by the above.
[0016]
The configuration 2 of the other invention is as follows:
A first electrode connected to a thin film transistor over a substrate having an insulating surface;
An insulator covering an end of the first electrode;
A light-emitting element having a layer containing an organic compound in contact with the first electrode and a second electrode in contact with the layer,
The light emitting device is characterized in that a central portion of the first electrode has a concave shape with a film thickness thinner than that of an end portion.
[0017]
Further, Configuration 3 of another invention is as follows.
A first electrode connected to a thin film transistor over a substrate having an insulating surface;
An insulator covering an end of the first electrode;
A light-emitting element having a layer containing an organic compound in contact with the first electrode and a second electrode in contact with the layer,
The first electrode has a multilayer structure, and the number of stacked end portions is larger than the number of stacked central portions of the first electrode.
[0018]
In addition, in the present invention, when an organic compound film made of a polymer is formed by a coating method, the shape of an insulator (referred to as a bank, a partition, a barrier, a bank, or the like) provided between pixels in order to eliminate poor coverage and the like. Add ingenuity to. In each of the above structures, the upper end portion of the insulator is provided with a curved surface having a curvature radius, and the curvature radius is 0.2 μm to 3 μm. The taper angle of the insulator may be 35 ° to 55 °.
[0019]
By providing curvature, the step coverage is good, and the film can be formed even if the layer containing an organic compound to be formed later is extremely thin.
[0020]
In each of the above structures, the first electrode has an inclined surface toward the central portion of the first electrode, and an inclination angle (also referred to as a taper angle) exceeds 30 °, less than 70 °, The angle is preferably less than 60 °. In addition, when calculated by performing simulation, the inclination angles with the best extraction efficiency are 54 and 7. The light reflected by the inclined surface of the first electrode is appropriately dispersed so that the light is not dispersed between the layers or becomes stray light, the material of the organic compound layer and the film thickness, or the material of the second electrode and It is necessary to set the film thickness.
[0021]
In each of the above structures, the second electrode is a conductive film that transmits light, such as a thin metal film or a transparent conductive film.
[0022]
In each of the above structures, the first electrode has a concave shape, and is formed in a self-aligning manner using the insulator as a mask. Therefore, there is no increase in the mask in forming the first electrode shape. Note that the step portion of the first electrode (upper end portion of the inclined portion) and the side surface of the insulator substantially coincide with each other, and the inclination angle and the insulation on the inclined surface of the first electrode are preferable from the viewpoint of step coverage. It is desirable that the inclination angle on the side surface of the object is the same.
[0023]
In each of the above structures, the first electrode is an anode, and the second electrode is a cathode. Alternatively, each of the above structures is characterized in that the first electrode is a cathode and the second electrode is an anode.
[0024]
In each of the above structures, the layer containing the organic compound is a material that emits white light, and is combined with a color filter provided in a sealing material, or the layer containing the organic compound is A light emitting device which is a material emitting monochromatic light and combined with a color conversion layer or a colored layer provided on a sealing material.
[0025]
Further, in the present invention, after the step of the first electrode is formed, a wiring (also called an auxiliary wiring or a third electrode) is formed on the insulator disposed between the pixel electrodes by a vapor deposition method using a vapor deposition mask, The film resistance of the electrode serving as the cathode (electrode that transmits light) may be reduced. It is also a feature of the present invention that a lead-out wiring is formed using the auxiliary wiring and is connected to another wiring existing in the lower layer.
[0026]
The configuration of the invention for realizing the above configurations 1, 2, and 3 is as follows.
A method for manufacturing a light emitting device having a light emitting element having an anode, a layer containing an organic compound in contact with the anode, and a cathode in contact with the layer containing the organic compound,
Forming an insulator covering an end of the first electrode made of a laminate of metal layers;
Etching using the insulator as a mask, and thinning the central portion of the first electrode so that the slope is exposed along the edge of the first electrode;
Forming a film containing an organic compound;
And a step of forming a second electrode made of a metal thin film that transmits light over a film containing the organic compound.
[0027]
In the structure related to the manufacturing method, the first electrode has a stack of a metal layer that reflects light and a metal layer that serves as an etching stopper, and the metal layer that reflects light is etched, and Is characterized in that a metal material that reflects light is exposed.
[0028]
Further, the surface of the metal layer serving as an etching stopper may be slightly etched by etching the first electrode.
[0029]
In the structure related to the above manufacturing method, the first electrode is an anode and is formed of a metal layer having a work function larger than that of the second electrode.
[0030]
In the structure related to the manufacturing method, the first electrode includes a first metal layer containing titanium, a second metal layer containing titanium nitride or tungsten nitride, a third metal layer containing aluminum, It is characterized by being a laminate with a fourth metal layer containing titanium nitride.
[0031]
Note that since the first metal layer is in contact with the source region or the drain region of the TFT, a metal material (typically titanium) having good ohmic contact with silicon may be selected, and the second metal layer functions as an anode. A material having a high work function is preferable as the metal layer, a metal material having high light reflectance is preferable as the third metal layer that reflects light of the light emitting element, and a third metal layer is used as the fourth metal layer. A metal material (titanium nitride or titanium) that prevents generation of hillocks and whiskers and prevents specular reflection of the third metal layer is preferable.
[0032]
The first electrode is not limited to the above four-layer structure, and is particularly limited as long as it is at least two layers of a metal layer that functions as an anode and a metal layer having a slope that reflects light of the light-emitting element. Not.
[0033]
FIG. 12 shows the reflectance of an aluminum film containing a small amount of Ti and the reflectance of a TiN film (100 nm). Titanium nitride is a material that can prevent specular reflection. Further, when titanium nitride is used as the anode, since it hardly reflects, interference due to the return light of the light emitting element does not occur. Therefore, a panel structure that does not require a circularly polarizing plate can be obtained.
[0034]
For example, in the first electrode, titanium as a first metal layer, titanium nitride as a second metal layer, a metal film containing aluminum as a third metal layer, titanium nitride as a fourth metal layer, A six-layer structure of a metal film containing aluminum as the metal layer and titanium nitride as the sixth metal layer may be used. In the case of this six-layer structure, the fourth metal layer is the anode, the light of the light emitting element is reflected by the slope of the fifth metal layer, and a metal film containing aluminum is provided under the anode. Therefore, the resistance of the entire first electrode can be reduced. In addition, this six-layer structure is particularly effective when one pixel area (light emitting region) is large or for a light emitting display device having a large screen.
[0035]
In the structure related to the above manufacturing method, the work function of the metal layer serving as the anode may be increased by performing ultraviolet irradiation treatment (referred to as UV ozone treatment) in an ozone atmosphere. FIG. 13 shows the results of measuring the change in work function with UV ozone treatment time. As shown in FIG. 13, titanium nitride has a work function of 4.7 eV, but the work function can be set to 5.05 eV by UV treatment (6 minutes). Similarly, tantalum nitride has a tendency to increase the work function. In the configuration related to the manufacturing method, N ₂ , O ₂ , Ar, BCl, Cl ₂ The work function of the metal layer serving as the anode may be increased by performing plasma treatment using one or more gases.
[0036]
Incidentally, in FIG. 13, the work function is measured in the atmosphere, and is measured by using a “photoelectron spectrometer AC-2” manufactured by Riken Keiki Co., Ltd. by photoelectron spectroscopy.
[0037]
In addition, when plasma etching is used in the step of thinning the central portion of the first electrode so that the slope is exposed along the edge of the first electrode using the insulator as a mask, Can increase the work function of the metal layer serving as the anode while making the central portion thinner.
[0038]
In the structure related to the manufacturing method, the insulator covering the end portion of the first electrode has a curved surface having a curvature radius at an upper end portion, and the curvature radius is 0.2 μm to 3 μm. It is characterized by.
[0039]
Note that the EL element includes a layer containing an organic compound (hereinafter, referred to as an EL layer) from which luminescence generated by applying an electric field is obtained, an anode, and a cathode. Luminescence in an organic compound includes light emission (fluorescence) when returning from a singlet excited state to a ground state and light emission (phosphorescence) when returning from a triplet excited state to a ground state, which are produced according to the present invention. The light emitting device can be applied to either light emission.
[0040]
A light-emitting element having an EL layer (EL element) has a structure in which the EL layer is sandwiched between a pair of electrodes. The EL layer usually has a stacked structure. Typically, a laminated structure of “hole transport layer / light emitting layer / electron transport layer” can be given. This structure has very high luminous efficiency, and most of the light emitting devices that are currently under research and development employ this structure.
[0041]
In addition, a hole injection layer / a hole transport layer / a light emitting layer / an electron transport layer, or a hole injection layer / a hole transport layer / a light emitting layer / an electron transport layer / an electron injection layer are sequentially laminated on the anode. Good structure. You may dope a fluorescent pigment | dye etc. with respect to a light emitting layer. These layers may all be formed using a low molecular weight material, or may be formed using a high molecular weight material. Note that in this specification, all layers provided between a cathode and an anode are collectively referred to as an EL layer. Therefore, the hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, and the electron injection layer are all included in the EL layer.
[0042]
In the light emitting device of the present invention, the screen display driving method is not particularly limited, and for example, a dot sequential driving method, a line sequential driving method, a surface sequential driving method, or the like may be used. Typically, a line sequential driving method is used, and a time-division gray scale driving method or an area gray scale driving method may be used as appropriate. The video signal input to the source line of the light-emitting device may be an analog signal or a digital signal, and a drive circuit or the like may be designed in accordance with the video signal as appropriate.
[0043]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
(Embodiment 1)
[0044]
A cross-sectional view (a part of one pixel) of the active matrix light-emitting device is shown in FIG. Here, a light-emitting element using a layer containing an organic compound made of a polymer material that emits white light as a light-emitting layer will be described as an example.
[0045]
In FIG. 1A, a TFT (p-channel TFT) provided on a substrate 10 having an insulating surface is an element for controlling a current flowing in an EL layer 20 that emits white light. Reference numerals 13 and 14 denote source regions. Or it is a drain region. A base insulating film 11 (here, a nitride insulating film as a lower layer and an oxide insulating film as an upper layer) is formed on the substrate 10, and a gate insulating film 12 is provided between the gate electrode 15 and the active layer. ing. 16a is an interlayer insulating film made of an organic material or an inorganic material, and 16b is a protective film made of a silicon nitride film, a silicon nitride oxide film, aluminum nitride, or aluminum nitride oxide. Although not shown here, one or more other TFTs (n-channel TFTs or p-channel TFTs) are provided in one pixel. Although a TFT having one channel formation region is shown here, the TFT is not particularly limited and may be a TFT having a plurality of channels.
[0046]
Further, 18a to 18d are first electrodes, that is, anodes (or cathodes) of the organic light emitting elements, and 21 is a second electrode made of a conductive film, that is, cathodes (or anodes) of the organic light emitting elements. is there. Here, 18a is a titanium film, 18b is a titanium nitride film, 18c is a film containing aluminum as a main component, 18d is sequentially laminated as a titanium nitride film, and 18b in contact with the layer 20 containing an organic compound functions as an anode. The power supply line 17 is also formed with the same laminated structure. The stacked structure includes a film containing aluminum as a main component, can be a low-resistance wiring, and the source wiring 22 and the like are formed at the same time.
[0047]
Further, in order to obtain white light emission, a poly (ethylenedioxythiophene) / poly (styrenesulfonic acid) aqueous solution (PEDOT / PSS) acting as a hole injection layer was applied and fired as the layer 20 containing an organic compound over the entire surface. Later, a luminescent center dye (1,1,4,4-tetraphenyl-1,3-butadiene (TPB), 4-dicyanomethylene-2-methyl-6- (p-dimethylamino-styryl) acting as a luminescent layer -4H-pyran (DCM1), Nile Red, Coumarin 6 etc.) doped polyvinylcarbazole (PVK) solution is applied to the entire surface and baked. PEDOT / PSS uses water as a solvent and does not dissolve in organic solvents. Therefore, when PVK is applied from above, there is no fear of redissolving. Further, since PEDOT / PSS and PVK have different solvents, it is preferable not to use the same film forming chamber. Alternatively, the layer 20 containing an organic compound can be a single layer, and an electron transporting 1,3,4-oxadiazole derivative (PBD) may be dispersed in hole transporting polyvinyl carbazole (PVK). . Further, white light emission can be obtained by dispersing 30 wt% PBD as an electron transporting agent and dispersing an appropriate amount of four kinds of dyes (TPB, coumarin 6, DCM1, Nile red).
[0048]
It is also possible to obtain white light emission as a whole by appropriately selecting a film containing an organic compound that emits red light, a film containing an organic compound that emits green light, or a film containing an organic compound that emits blue light, and mixing them in layers. .
[0049]
21 as CaF ₂ After forming the film 1 nm to 10 nm in thickness by vapor deposition, an Al film is finally formed with a film thickness of about 10 nm by sputtering or vapor deposition to function as a cathode. For the cathode, it is necessary to appropriately select a film thickness and a material through which light from the layer 20 containing an organic compound passes. Note that in this specification, a cathode includes not only a single-layer film of a material film with a low work function but also a stacked film of a material thin film with a low work function and a conductive film.
[0050]
When the Al film is used for the second electrode 21, the material in contact with the layer 20 containing an organic compound can be formed of a material other than an oxide, and the reliability of the light-emitting device can be improved. Instead of the Al film, a transparent conductive film (ITO (indium oxide tin oxide alloy), indium zinc oxide alloy (In ₂ O _Three -ZnO), zinc oxide (ZnO) or the like may be used. CaF ₂ Alternatively, a thin metal layer (typically an alloy such as MgAg, MgIn, or AlLi) may be used.
[0051]
Further, both ends of the first electrode 18 and the space between them are covered with an insulator 19 (also called a barrier or a bank). In the present invention, the cross-sectional shape of the insulator 19 is important. The concave shape of the first electrode 18 is formed by the etching process for forming the insulator 19. When the upper end portion of the insulator 19 does not have a curved surface, a film formation defect in which a convex portion is formed at the upper end portion of the insulator 19 is likely to occur. Therefore, in the present invention, a curved surface having a radius of curvature is formed at the upper end portion of the insulator 19, and a part of the first electrodes 18c and 18d is exposed along the curved surface to form a slope, which becomes a light emitting region. Etching is performed so that the first electrode 18b is exposed in the region. Further, a process (such as a CMP process) for flattening the exposed surface of the first electrode 18b may be performed. In addition, it is preferable that a curvature radius shall be 0.2 micrometer-3 micrometers. According to the present invention, coverage of an organic compound film or a metal film can be improved. The taper angle on the side surface of the insulator 19 and the taper angle on the slopes of the first electrodes 18c and 18d may both be 45 ° ± 10 °.
[0052]
For example, a positive acrylic resin as the insulator 19, Ti = 60 nm as the first electrode 18a, TiN = 100 nm as the first electrode 18b, Al—Ti = 350 nm as the first electrode 18c, and as the first electrode 18d When Ti = 100 nm, the etching conditions are ICP etching equipment and BCl as a reaction gas. _Three = 60 sccm, Cl ₂ = 20 sccm, 450 W RF (13.56 MHz) power is applied to the coil-type electrode at a pressure of 1.9 Pa, and 100 W RF (13.56 MHz) power is also applied to the substrate side (sample stage) for dry etching. Then, TiN (first electrode 18b) is exposed by over-etching for 15 seconds after Al-Ti (first electrode 18c) is etched.
[0053]
In the present invention, the light emitted from the organic compound layer 20 is reflected by the slopes of the first electrodes 18c and 18d to increase the total light extraction amount in the direction of the arrow shown in FIG. It is said.
[0054]
As shown in FIG. 1B, an auxiliary electrode 23 may be provided over the conductive film 21 in order to reduce the resistance of the conductive film (cathode) 21. The auxiliary electrode 23 may be selectively formed by a vapor deposition method using a vapor deposition mask.
[0055]
Although not shown, it is preferable to form a protective film over the second electrode 21 in order to increase the reliability of the light-emitting device. This protective film is an insulating film mainly containing silicon nitride or silicon nitride oxide obtained by sputtering (DC method or RF method), or a thin film mainly containing carbon. If a silicon target is used and formed in an atmosphere containing nitrogen and argon, a silicon nitride film can be obtained. A silicon nitride target may be used. Further, the protective film may be formed using a film forming apparatus using remote plasma. Further, in order to allow light emission to pass through the protective film, it is preferable to make the protective film as thin as possible.
[0056]
In the present invention, the carbon-based thin film is a DLC film (Diamond like Carbon) having a thickness of 3 to 50 nm. DLC films are short-range ordered as bonds between carbons, SP ^Three Although it has a bond, it has an amorphous structure macroscopically. The composition of the DLC film is 70 to 95 atomic% for carbon and 5 to 30 atomic% for hydrogen, and is very hard and excellent in insulation. Such a DLC film is also characterized by low gas permeability such as water vapor and oxygen. It is also known to have a hardness of 15 to 25 GPa as measured by a microhardness meter.
[0057]
The DLC film can be formed by a plasma CVD method (typically, an RF plasma CVD method, a microwave CVD method, an electron cyclotron resonance (ECR) CVD method, etc.), a sputtering method, or the like. Whichever film formation method is used, the DLC film can be formed with good adhesion. The DLC film is formed by placing the substrate on the cathode. Alternatively, a dense and hard film can be formed by applying a negative bias and utilizing ion bombardment to some extent.
[0058]
The reaction gas used for film formation includes hydrogen gas and hydrocarbon-based gas (for example, CH _Four , C ₂ H ₂ , C ₆ H ₆ And the like, and ionized by glow discharge, and the ions are accelerated and collided with a negative self-biased cathode to form a film. By doing so, a dense and smooth DLC film can be obtained. The DLC film is an insulating film that is transparent or translucent to visible light.
[0059]
In the present specification, transparent to visible light means that the visible light transmittance is 80 to 100%, and translucent to visible light is a visible light transmittance of 50 to 80%. Refers to that.
[0060]
Although the top gate type TFT has been described as an example here, the present invention can be applied regardless of the TFT structure. For example, it can be applied to a bottom gate type (reverse stagger type) TFT or a forward stagger type TFT. Is possible.
[0061]
(Embodiment 2)
A method of combining a white light emitting element and a color filter (hereinafter referred to as a color filter method) will be described below with reference to FIG.
[0062]
The color filter method is a method in which red light, green light, and blue light emission are obtained by forming a light emitting element having an organic compound film that emits white light and passing the obtained white light through a color filter.
[0063]
There are various methods for obtaining white light emission. Here, a case where a light emitting layer made of a polymer material that can be formed by coating is used will be described. In this case, the dye doping of the polymer material to be the light emitting layer can be performed by adjusting the solution, and can be obtained extremely easily as compared with the vapor deposition method in which co-evaporation in which a plurality of dyes are doped is performed.
[0064]
Specifically, poly (ethylenedioxythiophene) / poly (styrenesulfone) acting as a hole injection layer on an anode made of a metal having a high work function (Pt, Cr, W, Ni, Zn, Sn, In). Acid) Aqueous solution (PEDOT / PSS) is applied to the entire surface and baked, and then a luminescent center dye (1,1,4,4-tetraphenyl-1,3-butadiene (TPB), 4-dicyanomethylene acting as a luminescent layer) -2-methyl-6- (p-dimethylamino-styryl) -4H-pyran (DCM1), Nile red, coumarin 6 etc.) doped polyvinylcarbazole (PVK) solution was applied to the entire surface and baked. A thin film containing a small metal (Li, Mg, Cs), and a transparent conductive film (ITO (indium tin oxide alloy), indium zinc oxide alloy ( n ₂ O _Three -ZnO), zinc oxide (ZnO), etc.) to form a cathode. PEDOT / PSS uses water as a solvent and does not dissolve in organic solvents. Therefore, when PVK is applied from above, there is no fear of redissolving. Further, since PEDOT / PSS and PVK have different solvents, it is preferable not to use the same film forming chamber.
[0065]
Moreover, although the example which made the organic compound layer laminated | stacked was shown in the said example, an organic compound layer can also be made into a single layer. For example, an electron transporting 1,3,4-oxadiazole derivative (PBD) may be dispersed in hole transporting polyvinyl carbazole (PVK). Further, white light emission can be obtained by dispersing 30 wt% PBD as an electron transporting agent and dispersing an appropriate amount of four kinds of dyes (TPB, coumarin 6, DCM1, Nile red).
[0066]
The organic compound film is formed between the anode and the cathode, and the holes injected from the anode and the electrons injected from the cathode are recombined in the organic compound film, so that the organic compound film emits white light. Is obtained.
[0067]
It is also possible to obtain white light emission as a whole by appropriately selecting an organic compound film emitting red light, an organic compound film emitting green light, or an organic compound film emitting blue light and mixing them in layers.
[0068]
The organic compound film formed as described above can obtain white light emission as a whole.
[0069]
A color provided with a colored layer (R) that absorbs light other than red light, a colored layer (G) that absorbs light other than green light, and a colored layer (B) that absorbs light other than blue light in the direction in which the organic compound film emits white light. By forming the filter, white light emission from the light emitting element can be separated and obtained as red light emission, green light emission, and blue light emission. In the case of the active matrix type, a TFT is formed between the substrate and the color filter.
[0070]
In addition, the colored layer (R, G, B) can use the simplest stripe pattern, diagonal mosaic arrangement, triangular mosaic arrangement, RGBG four-pixel arrangement, or RGBW four-pixel arrangement.
[0071]
The colored layer constituting the color filter is formed using a color resist made of an organic photosensitive material in which a pigment is dispersed. The chromaticity coordinates of white light emission are (x, y) = (0.34, 0.35). By combining white light emission and a color filter, sufficient color reproducibility as a full color can be ensured.
[0072]
In this case, even if the luminescent color obtained is different, all the organic compound films exhibiting white luminescence are formed, so that it is not necessary to separately form the organic compound film for each luminescent color. Further, a circularly polarizing plate that prevents specular reflection can be omitted.
[0073]
Next, a CCM method (color changing mediums) realized by combining a blue light emitting element having a blue light emitting organic compound film and a fluorescent color conversion layer will be described with reference to FIG.
[0074]
In the CCM method, blue light emitted from a blue light emitting element excites a fluorescent color conversion layer, and color conversion is performed in each color conversion layer. Specifically, the color conversion layer converts blue to red (B → R), the color conversion layer converts blue to green (B → G), and the color conversion layer converts blue to blue (B → B). ) (Note that the conversion from blue to blue is not necessary) to obtain red, green and blue light emission. Also in the case of the CCM method, the active matrix type has a structure in which TFTs are formed between the substrate and the color conversion layer.
[0075]
In this case, it is not necessary to form the organic compound film separately. Further, a circularly polarizing plate that prevents specular reflection can be omitted.
[0076]
Further, when the CCM method is used, since the color conversion layer is fluorescent, it is excited by external light and has a problem of lowering the contrast. Therefore, a color filter is attached as shown in FIG. To increase the contrast.
[0077]
Further, this embodiment mode can be combined with Embodiment Mode 1.
[0078]
(Embodiment 3)
Here, the entire EL module and the arrangement of the desiccant will be described with reference to FIG. 4A is a top view of the EL module, and FIG. 4B is a part of a cross-sectional view.
[0079]
A substrate provided with an infinite number of TFTs (also referred to as a TFT substrate) includes a pixel portion 40 on which display is performed, drive circuits 41a and 41b for driving each pixel of the pixel portion, and electrodes and leads provided on the EL layer. A connection part for connecting the wiring, a terminal part 42 for attaching the FPC for connection to an external circuit, and a desiccant 44 are provided. 4 (A) and 4 (B) are arranged so as to partially overlap, but as shown in FIG. 4 (C), the entire driving circuit may be hidden by the desiccant. Good. Further, the EL element is sealed with a substrate for sealing the EL element and a sealing material 49. FIG. 4B is a cross-sectional view taken along the chain line AA ′ in FIG.
[0080]
Innumerable pixels are regularly arranged in the pixel section 40, and although not shown here, they are arranged in the order of R, G, and B in the X direction.
[0081]
Further, as shown in FIG. 4B, a sealing substrate 48 is attached by a sealing material 49 so as to keep an interval of about 2 to 30 μm, and all the light emitting elements are sealed. A recess is formed in the sealing substrate 48 by a sandblast method or the like, and a desiccant is disposed in the recess. The sealing material 49 is preferably narrowed so as to overlap a part of the drive circuit. It is preferable to perform deaeration by annealing in a vacuum just before the sealing substrate 48 is attached by the sealing material 49. In addition, the sealing substrate 48 is preferably attached in an atmosphere containing an inert gas (rare gas or nitrogen).
[0082]
Further, this embodiment can be freely combined with Embodiment 1 or Embodiment 2.
[0083]
The present invention having the above-described configuration will be described in more detail with the following examples.
[0084]
(Example)
[Example 1]
In this example, an example of a procedure for forming a light-emitting element of the present invention will be briefly described below with reference to FIGS.
[0085]
First, the base insulating film 31 is formed over the substrate 30 having an insulating surface.
[0086]
The base insulating film 31 uses a plasma CVD method as a first layer, and is made of SiH. _Four , NH _Three And N ₂ A silicon oxynitride film formed using O as a reaction gas is formed to a thickness of 10 to 200 nm (preferably 50 to 100 nm). Here, a silicon oxynitride film (composition ratio: Si = 32%, O = 27%, N = 24%, H = 17%) with a thickness of 50 nm is formed. Next, as the second layer of the base insulating film, a plasma CVD method is used, and SiH _Four And N ₂ A silicon oxynitride film formed using O as a reaction gas is formed to a thickness of 50 to 200 nm (preferably 100 to 150 nm). Here, a 100-nm-thick silicon oxynitride film (composition ratio Si = 32%, O = 59%, N = 7%, H = 2%) is formed. In this embodiment, a two-layer structure is used as the base insulating film 31, but a single-layer film of the insulating film or a structure in which three or more layers are stacked may be used.
[0087]
Next, a semiconductor layer is formed over the base film. The semiconductor layer which becomes the active layer of the TFT is formed by forming a semiconductor film having an amorphous structure by a known means (sputtering method, LPCVD method, plasma CVD method, etc.) and then a known crystallization treatment (laser crystallization). A crystalline semiconductor film obtained by performing a method, a thermal crystallization method, or a thermal crystallization method using a catalyst such as nickel) is formed into a desired shape by patterning. The semiconductor layer is formed with a thickness of 25 to 80 nm (preferably 30 to 60 nm). There is no limitation on the material of the crystalline semiconductor film, but it is preferably formed of silicon or a silicon germanium alloy.
[0088]
When a crystalline semiconductor film is formed by laser crystallization, a pulse oscillation type or continuous emission type excimer laser, YAG laser, YVO _Four A laser can be used. When these lasers are used, it is preferable to use a method in which laser light emitted from a laser oscillator is linearly collected by an optical system and irradiated onto a semiconductor film. Crystallization conditions are appropriately selected by the practitioner. When an excimer laser is used, the pulse oscillation frequency is 30 Hz and the laser energy density is 100 to 400 mJ / cm. ² (Typically 200-300mJ / cm ² ). When a YAG laser is used, the second harmonic is used and the pulse oscillation frequency is 1 to 10 kHz, and the laser energy density is 300 to 600 mJ / cm. ² (Typically 350-500mJ / cm ² ) Then, when the laser beam condensed linearly with a width of 100 to 1000 μm, for example 400 μm, is irradiated over the entire surface of the substrate, the superposition ratio (overlap ratio) of the linear laser light at this time is 80 to 98%. Good.
[0089]
Next, the surface of the semiconductor layer is washed with an etchant containing hydrofluoric acid to form a gate insulating film 33 that covers the semiconductor layer. The gate insulating film 33 is formed of an insulating film containing silicon with a thickness of 40 to 150 nm by using a plasma CVD method or a sputtering method. In this embodiment, a silicon oxynitride film (composition ratio: Si = 32%, O = 59%, N = 7%, H = 2%) is formed to a thickness of 115 nm by plasma CVD. Needless to say, the gate insulating film is not limited to the silicon oxynitride film, and another insulating film containing silicon may be used as a single layer or a stacked structure.
[0090]
Next, after cleaning the surface of the gate insulating film 33, a gate electrode is formed.
[0091]
Next, an impurity element imparting p-type conductivity to the semiconductor (such as B), here boron, is added as appropriate to form the source region and the drain region 32. After the addition, heat treatment, intense light irradiation, or laser light irradiation is performed to activate the impurity element. Simultaneously with activation, plasma damage to the gate insulating film and plasma damage to the interface between the gate insulating film and the semiconductor layer can be recovered. In particular, in an atmosphere of room temperature to 300 ° C., it is very effective to activate the impurity element by irradiating the second harmonic of the YAG laser from the front surface or the back surface. A YAG laser is a preferred activation means because it requires less maintenance.
[0092]
In the subsequent steps, an interlayer insulating film 35 made of an organic material or an inorganic material (coating silicon oxide film, PSG (including phosphorus-added glass, BPSG (glass added with boron and phosphorus)), etc. is formed and hydrogenated. Then, contact holes reaching the source region or the drain region are formed, and then a source electrode (wiring) and a first electrode (drain electrode) 36 are formed to complete a TFT (p-channel TFT).
[0093]
In this embodiment, the p-channel TFT is used for explanation. However, it goes without saying that an n-channel TFT can be formed by using an n-type impurity element (P, As, etc.) instead of the p-type impurity element. Yes.
[0094]
In this embodiment, the top gate type TFT is described as an example. However, the present invention can be applied regardless of the TFT structure. For example, the present invention can be applied to a bottom gate type (reverse stagger type) TFT or a forward stagger type TFT. Is possible.
[0095]
Through the above steps, the TFT (only the drain region 32 is shown here), the gate insulating film 33, the interlayer insulating film 35, and the first electrodes 36a to 36d are formed. (Fig. 3 (A))
[0096]
In this embodiment, the first electrodes 36a to 36d are Ti, TiN, TiSi. _X N _Y , Al, Ag, Ni, W, WSi _X , WN _X , WSi _X N _Y , Ta, TaN _X , TaSi _X N _Y NbN, MoN, Cr, Pt, Zn, Sn, In, or an element selected from Mo, an alloy material or a compound material containing the element as a main component, or a laminated film of these films as a total film What is necessary is just to use in the range of thickness 100nm -800nm.
[0097]
In particular, the first electrode 36a in contact with the drain region 32 is preferably made of a material capable of forming ohmic contact with silicon, typically titanium, and may have a thickness of 10 to 100 nm. Further, the first electrode 36b is preferably made of a material having a large work function (TiN, TaN, MoN, Pt, Cr, W, Ni, Zn, Sn) when it is formed as a thin film, and has a thickness of 10 to 100 nm. That's fine. The first electrode 36c is preferably a metal material that reflects light, typically a metal material mainly containing Al or Ag, and may have a thickness in the range of 100 to 600 nm. Note that the first electrode 36b also functions as a blocking layer that prevents alloying of the first electrode 36c and the first electrode 36a. The first electrode 36d is preferably made of a material that prevents oxidation, corrosion, or hillock generation of the first electrode 36c, typically metal nitride (TiN, WN, etc.), and has a thickness of 20 to The range may be 100 nm.
[0098]
The first electrodes 36a to 36d can be formed at the same time as other wirings such as the source wiring 34 and the power supply line. Therefore, a process with a small number of photomasks (patterning mask for semiconductor layer (first sheet), patterning mask for gate wiring (second sheet), doping mask for selectively adding an n-type impurity element (third sheet) ), A doping mask for selectively adding a p-type impurity element (fourth sheet), a mask for forming a contact hole reaching the semiconductor layer (fifth sheet), the first electrode, the source wiring, and the power supply line A total of seven patterning masks (sixth sheet) and insulator formation masks (seventh sheet). Conventionally, since the first electrode is formed in a layer different from the source wiring and the power supply line, a mask for forming only the first electrode is necessary, and the total number is eight. Further, when the first electrodes 36a to 36d and the wiring are formed at the same time, it is desirable that the total electric resistance value as the wiring is low.
[0099]
Next, an insulator (referred to as a bank, a partition, a barrier, a bank, or the like) is formed to cover an end portion of the first electrode (and a contact portion with the drain region 32). (FIG. 3B) As the insulator, inorganic materials (silicon oxide, silicon nitride, silicon oxynitride, etc.), photosensitive or non-photosensitive organic materials (polyimide, acrylic, polyamide, polyimide amide, resist, or benzocyclo) Butene) or a laminate of these can be used. In this embodiment, a photosensitive organic resin is used. For example, when positive photosensitive acrylic is used as the material of the insulator, it is preferable that only the upper end portion of the insulator has a curved surface having a curvature radius. As the insulator, either a negative type that becomes insoluble in an etchant by photosensitive light or a positive type that becomes soluble in an etchant by light can be used.
[0100]
Next, as shown in FIG. 3C, the first electrodes 36c and 36d are partially removed while etching the insulator. It is important to perform etching so that an inclined surface is formed on the exposed surface of the first electrode 36c and the exposed surface of the first electrode 36b is flat. This etching may be performed once or a plurality of times by dry etching or wet etching, and a condition with a high selection ratio is selected between the first electrode 36b and the first electrode 36c. And it is preferable that the final curvature radius of the upper end part of an insulator shall be 0.2 micrometer-3 micrometers. In addition, the angle of the inclined surface (tilt angle, taper angle) toward the center of the first electrode is more than 30 ° and less than 70 °, and light emitted from a layer containing an organic compound to be formed later is reflected. Let
[0101]
Next, a layer 38 containing an organic compound is formed using a vapor deposition method or a coating method. For example, when the vapor deposition method is used, the degree of vacuum is 5 × 10. ^-3 Torr (0.665 Pa) or less, preferably 10 ^-Four -10 ^-6 Vapor deposition is performed in a deposition chamber evacuated to Pa. At the time of vapor deposition, the organic compound is vaporized by resistance heating in advance, and is scattered in the direction of the substrate by opening the shutter at the time of vapor deposition. The vaporized organic compound scatters upward and is deposited on the substrate through an opening provided in the metal mask. By laminating by vapor deposition, a layer containing an organic compound showing white as the whole light emitting element is formed.
[0102]
For example, Alq _Three , Alq partially doped with Nile Red, a red luminescent dye _Three , Alq _Three , P-EtTAZ, and TPD (aromatic diamine) are sequentially laminated to obtain a white color.
[0103]
Moreover, when forming the layer containing an organic compound by the apply | coating method using spin coating, after apply | coating, it is preferable to bake by vacuum heating. For example, a poly (ethylenedioxythiophene) / poly (styrenesulfonic acid) aqueous solution (PEDOT / PSS) that acts as a hole injection layer is applied and fired on the entire surface, and then a luminescent center dye (1, 1,4,4-tetraphenyl-1,3-butadiene (TPB), 4-dicyanomethylene-2-methyl-6- (p-dimethylamino-styryl) -4H-pyran (DCM1), Nile Red, Coumarin 6 Etc.) A doped polyvinyl carbazole (PVK) solution may be applied to the entire surface and fired.
[0104]
Moreover, although the example which made the organic compound layer laminated | stacked was shown in the said example, an organic compound layer can also be made into a single layer. For example, an electron transporting 1,3,4-oxadiazole derivative (PBD) may be dispersed in hole transporting polyvinyl carbazole (PVK). Further, white light emission can be obtained by dispersing 30 wt% PBD as an electron transporting agent and dispersing an appropriate amount of four kinds of dyes (TPB, coumarin 6, DCM1, Nile red). Further, as the organic compound layer, a layer made of a high molecular material and a layer made of a low molecular material may be laminated.
[0105]
Next, a metal having a small work function (MgAg, MgIn, AlLi, CaF ₂ And a thin conductive film (in this case, an aluminum film) 39 thereon, an alloy such as CaN, or a film formed by co-evaporation of aluminum and an element belonging to Group 1 or Group 2 of the periodic table) Evaporate and stack. (FIG. 2B) An aluminum film is a film having a high ability to block moisture and oxygen, and is a preferable material for the conductive film 39 in order to improve the reliability of the light-emitting device. Note that FIG. 2B shows a cross section taken along the chain line AA ′ in FIG. This laminated film is thin enough to pass light emission and functions as a cathode in this embodiment. Also, instead of a thin conductive film, a transparent conductive film (ITO (indium tin oxide alloy), indium zinc oxide alloy (In ₂ O _Three -ZnO), zinc oxide (ZnO) or the like may be used. An auxiliary electrode may be provided on the conductive film 39 in order to reduce the resistance of the cathode. Further, when the cathode is formed, a resistance heating method by vapor deposition is used, and the cathode may be selectively formed using a vapor deposition mask.
[0106]
The light-emitting element thus obtained can emit white light in the direction of the arrow in FIG. 2B and can reflect the light emitted in the horizontal direction on the inclined surface of the first electrode 36c to increase the amount of light emitted in the direction of the arrow. .
[0107]
After the formation up to the second electrode (conductive film 39) through the above steps, a sealing substrate (transparent substrate) is bonded with a sealant to seal the light emitting element formed on the substrate 30. Note that a spacer made of a resin film may be provided in order to ensure a space between the sealing substrate and the light emitting element. The space inside the sealing agent is filled with an inert gas such as nitrogen. In addition, it is preferable to use an epoxy resin as the sealing agent. Further, it is desirable that the sealant is a material that does not transmit moisture and oxygen as much as possible. Furthermore, a substance (such as a desiccant) having an effect of absorbing oxygen and water may be included in the space.
[0108]
By encapsulating the light emitting element in the space as described above, the light emitting element can be completely blocked from the outside, and can prevent the entry of substances that promote deterioration of the organic compound layer such as moisture and oxygen from the outside. it can. Therefore, a highly reliable light-emitting device can be obtained.
[0109]
[Example 2]
In this embodiment, an example in which an auxiliary electrode is formed will be described below with reference to FIGS.
[0110]
FIG. 6A is a top view of the pixel, and FIG. 6B is a cross-sectional view taken along the chain line AA ′.
[0111]
In this embodiment, the steps until the insulator 67 is formed are the same as those in Embodiment 1, and therefore are omitted here. The insulator 37 in FIG. 2B corresponds to the insulator 67 in FIG. 6B.
[0112]
In accordance with Embodiment 1, a base insulating film, a drain region 62, a gate insulating film 63, an interlayer insulating film 65, first electrodes 66a to 66d, and an insulator 67 are formed over a substrate having an insulating surface.
[0113]
Next, a layer 68 containing an organic compound is selectively formed. In this embodiment, the layer 68 containing an organic compound is selectively formed by an evaporation method using an evaporation mask or an ink jet method.
[0114]
Next, the auxiliary electrode 60 is selectively formed on the insulator 67 by a vapor deposition method using a vapor deposition mask. What is necessary is just to set the film thickness of the auxiliary electrode 60 in the range of 0.2 micrometer-0.5 micrometer. In this embodiment, the example in which the auxiliary electrode 60 is arranged in the Y direction as shown in FIG. 6A is shown, but there is no particular limitation, and the auxiliary electrode 70 may be arranged in the X direction as shown in FIG. Good. Note that a cross-sectional view taken along the chain line AA ′ shown in FIG. 7 is the same as FIG.
[0115]
FIG. 8 shows an external view of a panel corresponding to FIG. The auxiliary electrode (auxiliary wiring) 70 is routed as shown in FIG. 8, and is formed so as to be in contact with the routing wiring 87 in a region between the pixel portion 82 and the source side driving circuit 83. In FIG. 8, reference numeral 82 denotes a pixel portion, 83 denotes a source side driver circuit, 84 and 85 denote gate side driver circuits, and 86 denotes a power supply line. In addition, wirings formed at the same time as the first electrode are a power supply line 86, a lead wiring 87, and a source wiring. In FIG. 8, a terminal electrode connected to the FPC is formed simultaneously with the gate wiring.
[0116]
Next, as in Example 1, a metal having a small work function (MgAg, MgIn, AlLi, CaF ₂ And a thin conductive film (in this case, an aluminum film) 69 thereon, an alloy such as CaN, or a film formed by co-evaporation of an element belonging to Group 1 or Group 2 of the periodic table and aluminum) Evaporate and stack. This laminated film is thin enough to pass light emission and functions as a cathode in this embodiment. Also, instead of a thin conductive film, a transparent conductive film (ITO (indium tin oxide alloy), indium zinc oxide alloy (In ₂ O _Three -ZnO), zinc oxide (ZnO) or the like may be used. In this embodiment, the auxiliary electrode 60 is provided on the insulator 67 so as to be in contact with the conductive film 69 in order to reduce the resistance of the cathode.
[0117]
The light-emitting element thus obtained can emit white light in the direction of the arrow in FIG. 6B and can reflect the light emitted in the horizontal direction on the inclined surface of the first electrode 66c to increase the amount of light emitted in the direction of the arrow. .
[0118]
In addition, since the auxiliary electrode 60, 70 is formed in this embodiment to reduce the resistance of the cathode, it can be applied to a pixel portion having a large size.
[0119]
In the present embodiment, the example in which the auxiliary electrode 60 is formed after the layer 68 containing the organic compound is formed is shown. However, the formation order is not particularly limited, and the organic compound is included after the auxiliary electrode 60 is formed. A layer may be formed.
[0120]
In addition, this embodiment can be freely combined with any one of Embodiment Modes 1 to 3 and Embodiment 1.
[0121]
[Example 3]
In this embodiment, an external view of the entire active matrix light emitting device will be described with reference to FIG. 9A is a top view illustrating the light-emitting device, and FIG. 9B is a cross-sectional view taken along line AA ′ in FIG. 9A. Reference numeral 901 indicated by a dotted line denotes a source signal line driver circuit, 902 denotes a pixel portion, and 903 denotes a gate signal line driver circuit. Reference numeral 904 denotes a sealing substrate, reference numeral 905 denotes a sealant, and the inside surrounded by the sealant 905 is a space 907.
[0122]
Note that reference numeral 908 denotes wiring for transmitting signals input to the source signal line driver circuit 901 and the gate signal line driver circuit 903, and a video signal and a clock signal are received from an FPC (flexible printed circuit) 909 serving as an external input terminal. receive. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC. The light-emitting device in this specification includes not only a light-emitting device body but also a state in which an FPC or a PWB is attached thereto.
[0123]
Next, a cross-sectional structure is described with reference to FIG. A driver circuit and a pixel portion are formed over the substrate 910. Here, a source signal line driver circuit 901 and a pixel portion 902 are shown as the driver circuits.
[0124]
Note that as the source signal line driver circuit 901, a CMOS circuit in which an n-channel TFT 923 and a p-channel TFT 924 are combined is formed. The TFT forming the driving circuit may be formed by a known CMOS circuit, PMOS circuit or NMOS circuit. Further, in this embodiment, a driver integrated type in which a drive circuit is formed on a substrate is shown, but this is not always necessary, and it can be formed outside the substrate.
[0125]
The pixel portion 902 is formed by a plurality of pixels including a switching TFT 911, a current control TFT 912, and a first electrode (anode) 913 electrically connected to the drain thereof.
[0126]
An insulating layer 914 is formed on both ends of the first electrode (anode) 913, and a part of the first electrode has a slope along the side surface of the insulating layer 914. The slope of the first electrode is formed at the same time as the insulating layer 914 is formed. The light emitted from the layer 915 containing an organic compound is reflected by this inclined surface, and the light emission amount in the light emission direction indicated by the arrow in FIG. 9 is increased.
[0127]
A layer 915 containing an organic compound is selectively formed over the first electrode (anode) 913. Further, a second electrode (cathode) 916 is formed over the layer 915 containing an organic compound. Thus, a light-emitting element 918 including the first electrode (anode) 912, the layer 915 containing an organic compound, and the second electrode (cathode) 916 is formed. Here, since the light-emitting element 918 emits white light, a color filter including a colored layer 931 and a BM 932 (overcoat layer is not shown here for simplification) is provided.
[0128]
In addition, a third electrode (auxiliary electrode) 917 which is a part of the configuration shown in Embodiment 2 is formed over the insulating layer 914, and the resistance of the second electrode is reduced. The second electrode (cathode) 916 also functions as a wiring common to all pixels, and is electrically connected to the FPC 909 via the third electrode 917 and the connection wiring 908.
[0129]
In addition, in order to seal the light emitting element 918 formed over the substrate 910, the sealing substrate 904 is attached with a sealant 905. Note that a spacer made of a resin film may be provided in order to secure a space between the sealing substrate 904 and the light-emitting element 918. A space 907 inside the sealing agent 905 is filled with an inert gas such as nitrogen. Note that an epoxy resin is preferably used as the sealant 905. In addition, the sealant 905 is desirably a material that does not transmit moisture and oxygen as much as possible. Furthermore, a substance having an effect of absorbing oxygen and water may be contained in the space 907.
[0130]
Further, in this embodiment, a plastic substrate made of FRP (Fiberglass-Reinforced Plastics), PVF (polyvinyl fluoride), Mylar, polyester, acrylic, or the like is used as a material constituting the sealing substrate 904 as a material constituting the sealing substrate 904. be able to. In addition, after the sealing substrate 904 is bonded using the sealing agent 905, the sealing substrate 904 can be further sealed with a sealing agent so as to cover the side surface (exposed surface).
[0131]
By encapsulating the light emitting element in the space 907 as described above, the light emitting element can be completely blocked from the outside, and a substance that promotes deterioration of the organic compound layer such as moisture and oxygen can be prevented from entering from the outside. Can do. Therefore, a highly reliable light-emitting device can be obtained.
[0132]
In addition, this embodiment can be freely combined with Embodiment Modes 1 to 3, Embodiment 1, and Embodiment 2.
[0133]
[Example 4]
By implementing the present invention, all electronic devices incorporating a module having an organic light emitting element (active matrix EL module) are completed.
[0134]
Such electronic devices include video cameras, digital cameras, head mounted displays (goggles type displays), car navigation systems, projectors, car stereos, personal computers, personal digital assistants (mobile computers, mobile phones, electronic books, etc.), etc. Can be mentioned. Examples of these are shown in FIGS.
[0135]
FIG. 10A illustrates a personal computer, which includes a main body 2001, an image input portion 2002, a display portion 2003, a keyboard 2004, and the like.
[0136]
FIG. 10B illustrates a video camera, which includes a main body 2101, a display portion 2102, an audio input portion 2103, operation switches 2104, a battery 2105, an image receiving portion 2106, and the like.
[0137]
FIG. 10C illustrates a mobile computer, which includes a main body 2201, a camera unit 2202, an image receiving unit 2203, operation switches 2204, a display unit 2205, and the like.
[0138]
FIG. 10D illustrates a goggle type display, which includes a main body 2301, a display portion 2302, an arm portion 2303, and the like.
[0139]
FIG. 10E shows a player using a recording medium (hereinafter referred to as a recording medium) on which a program is recorded, and includes a main body 2401, a display portion 2402, a speaker portion 2403, a recording medium 2404, an operation switch 2405, and the like. This player uses a DVD (Digital Versatile Disc), CD, or the like as a recording medium, and can perform music appreciation, movie appreciation, games, and the Internet.
[0140]
FIG. 10F illustrates a digital camera, which includes a main body 2501, a display portion 2502, an eyepiece portion 2503, operation switches 2504, an image receiving portion (not shown), and the like.
[0141]
FIG. 11A shows a cellular phone, which includes a main body 2901, an audio output portion 2902, an audio input portion 2903, a display portion 2904, operation switches 2905, an antenna 2906, an image input portion (CCD, image sensor, etc.) 2907, and the like.
[0142]
FIG. 11B illustrates a portable book (electronic book), which includes a main body 3001, display portions 3002 and 3003, a storage medium 3004, operation switches 3005, an antenna 3006, and the like.
[0143]
FIG. 11C illustrates a display, which includes a main body 3101, a support base 3102, a display portion 3103, and the like.
[0144]
Incidentally, the display shown in FIG. 11C is a medium or small size display, for example, a screen size of 5 to 20 inches. Further, in order to form a display portion having such a size, it is preferable to use a substrate having a side of 1 m and perform mass production by performing multiple chamfering. In the case of a medium or small size or large size, it is preferable to form the auxiliary electrode shown in Example 2 or Example 3.
[0145]
As described above, the applicable range of the present invention is so wide that the present invention can be applied to methods for manufacturing electronic devices in various fields. In addition, the electronic device of this example can be realized by using any combination of Embodiment Modes 1 to 3 and Examples 1 to 3.
[0146]
【The invention's effect】
According to the present invention, among the light emitted from the layer containing an organic compound, the light emitted in the lateral direction (direction parallel to the substrate surface) is reflected by the inclined surface formed on the step portion of the first electrode, and then is transmitted in a certain direction The total amount of light emitted in the direction of passing through the two electrodes) can be increased. That is, a light-emitting device with little loss of light emission such as stray light can be realized.
[0147]
The structure of the present invention can be a manufacturing process with a small total number of masks.
[Brief description of the drawings]
FIG. 1 is a diagram showing Embodiment Mode 1;
2 is a diagram showing Example 1. FIG.
3 is a diagram showing Example 1. FIG.
FIG. 4 shows a third embodiment.
FIG. 5 shows a second embodiment.
6 is a diagram showing Example 2. FIG.
7 shows a second embodiment. FIG.
8 is a diagram showing Example 2. FIG.
FIG. 9 shows a third embodiment.
FIG 10 illustrates an example of an electronic device.
FIG 11 illustrates an example of an electronic device.
FIG. 12 is a graph showing the reflectance of an aluminum film containing a small amount of Ti and the reflectance of a TiN film (100 nm).
FIG. 13 is a graph showing the change in work function with UV ozone treatment time.

Claims (16)

A first electrode connected to a thin film transistor formed over a substrate having an insulating surface;
An insulator covering an end of the first electrode;
A layer containing an organic compound in contact with the first electrode;
A light emitting device having a second electrode in contact with the layer,
The light emitting device is characterized in that the first electrode has a multilayer structure and has a portion with a smaller number of stacked layers than an end portion of the first electrode. Oite to claim 1, wherein the second electrode is light-emitting device which is a conductive film which transmits light. According to claim 1 or 2, wherein the first electrode is an anode, the light emitting device, wherein said second electrode is a cathode. According to claim 1 or 2, wherein the first electrode is a cathode, the light emitting device, wherein the second electrode is an anode. In any one of claims 1 to 4, wherein the first electrode has an inclined surface forming a recess shape, the inclination angle of the inclined surface, and less than 70 ° beyond the 30 ° Light emitting device. In any one of claims 1 to 5, wherein the insulator covering an end portion of the first electrode has a curved surface with a curvature radius of the upper portion, the radius of curvature, in 0.2μm~3μm There is a light emitting device. In any one of claims 1 to 6, wherein the first electrode includes a first metal layer comprising titanium, a third metal layer comprising a second metal layer including titanium nitride or tungsten nitride, aluminum And a fourth metal layer containing titanium nitride. In any one of claims 1 to 7, the layer containing an organic compound, the light emitting device according to claim material emitting red light, the material emitting green light, or that it is a material which emits blue light. In any one of claims 1 to 7, the layer containing an organic compound is a material that emits white light, the light emitting device, characterized in that in combination with a color filter provided in the sealing material. In any one of claims 1 to 7, the layer containing an organic compound is a material that single color emission, light emitting device, characterized in that in combination a color conversion layer provided on the sealing material or a coloring layer. In any one of claims 1 to 10, wherein the light emitting device is characterized in that a video camera, a digital camera, a goggle type display, a car navigation, a personal computer, a DVD player, an electronic game device or personal digital assistant, Light emitting device. A method for manufacturing a light-emitting device having a light-emitting element having a first electrode, a layer containing an organic compound in contact with the first electrode, and a second electrode in contact with the layer containing the organic compound,
Forming the insulator so as to cover an end portion of the first electrode having a stack of a metal layer that reflects light and a metal layer that serves as an etching stopper ;
Wherein by etching the insulator as a mask, the first electrode partially thin so inclined slope is formed on the first electrode,
The film is formed containing an organic compound to the first electrode and the insulator on which the inclined slopes are formed,
Forming the second electrode made of a conductive film that transmits light on the film containing the organic compound ;
A metal material that reflects light is exposed on an inclined surface formed in the first electrode by etching a metal layer that reflects the light included in the first electrode. A method for manufacturing a light-emitting device. The method for manufacturing a light-emitting device according to claim 12 , wherein the first electrode is an anode and includes a metal layer having a work function larger than that of the second electrode. 14. The first electrode according to claim 12 , wherein the first electrode includes a first metal layer containing titanium, a second metal layer containing titanium nitride or tungsten nitride, a third metal layer containing aluminum, and titanium nitride. A method for manufacturing a light-emitting device, which is a stack with a fourth metal layer containing In any one of claims 12 to 14, wherein the first electrode has an inclined surface forming a recess shape, the inclination angle of the inclined surface, luminescence and less than 70 ° beyond the 30 ° Device fabrication method. 16. The insulator according to claim 12 , wherein the insulator covering the end portion of the first electrode has a curved surface having a curvature radius at an upper end portion, and the curvature radius is 0.2 μm to 3 μm. A manufacturing method of a light-emitting device, which is characterized by the following.

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