JP4223218B2 - Light emitting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light-emitting device using a light-emitting element including a film containing an organic compound (hereinafter referred to as an “organic compound layer”) that can emit light by applying an electric field, an anode, and a cathode, and a method for manufacturing the same. About. In particular, the present invention relates to a light-emitting device using a light-emitting element whose driving voltage is lower than that of a conventional element and whose lifetime is long. Note that a light-emitting device in this specification refers to an image display device or a light-emitting device using a light-emitting element. In addition, connectors such as anisotropic conductive film ((FPC: Flexible Printed Circuit) or TAB (Tape Automated Bonding) tape or TCP (Tape Carrier Package) are attached to the light emitting element, printed on the end of TAB tape or TCP It is assumed that the light emitting device includes all modules provided with a wiring board or modules in which an IC (integrated circuit) is directly mounted on a light emitting element by a COG (Chip On Glass) method.
[0002]
[Prior art]
Light-emitting elements are attracting attention as next-generation flat panel display elements due to their characteristics such as thin and light weight, high-speed response, and direct current low voltage drive. Further, since it is a self-luminous type and has a wide viewing angle, the visibility is relatively good, and it is considered to be effective as an element used for a display screen of an appliance, and has been actively developed.
[0003]
The light-emitting mechanism of a light-emitting element that emits light by applying an electric field is such that electrons injected from the cathode and holes injected from the anode are contained in the organic compound layer by applying a voltage with the organic compound layer sandwiched between the electrodes. It is said that recombination at the emission center forms a molecular exciton, and when the molecular exciton returns to the ground state, it emits energy and emits light. Note that the type of molecular exciton formed by the organic compound can be a singlet excited state or a triplet excited state. However, in this specification, both excited states contribute to light emission. .
[0004]
Such a light emitting element is classified into a passive matrix type (simple matrix type) and an active matrix type depending on a driving method. However, an active matrix type is particularly attracting attention because high-definition display having a number of pixels equal to or greater than QVGA is possible.
[0005]
An active matrix light-emitting device having a light-emitting element has an element structure as shown in FIG. 2, in which a TFT 202 is formed over a substrate 201, and an interlayer insulating film 203 is formed over the TFT 202.
[0006]
Then, an anode (pixel electrode) 205 electrically connected to the TFT 202 by the wiring 204 is formed on the interlayer insulating film 203. As a material for forming the anode 205, a transparent conductive material having a large work function is suitable, such as ITO (indium tin oxides) and tin oxide (SnO).₂), Alloys made of indium oxide and zinc oxide (ZnO), gold semipermeable membrane, polyaniline, and the like have been proposed. Of these, ITO is most often used because it has a band gap of about 3.75 eV and high transparency in the visible light region.
[0007]
An organic compound layer 206 is formed on the anode 205. In the present specification, all layers provided between the anode and the cathode are defined as organic compound layers. Specifically, the organic compound layer 206 includes a light emitting layer, a hole injection layer, an electron injection layer, a hole transport layer, an electron transport layer, and the like. Basically, the light-emitting element has a structure in which an anode / light-emitting layer / cathode is laminated in order, and in addition to this structure, an anode / hole injection layer / light-emitting layer / cathode and an anode / hole injection layer. In some cases, the light emitting layer / the electron transporting layer / the cathode are laminated in this order.
[0008]
After the organic compound layer 206 is formed, the cathode 207 is formed, whereby the light emitting element 209 is formed. As the cathode, a metal having a small work function (typically a metal belonging to Group 1 or Group 2 of the periodic table) is often used. In the present specification, such metals (including alkali metals and alkaline earth metals) are referred to as “alkali metals”.
[0009]
In addition, a bank 208 made of an organic resin material is formed so as to cover the end portion of the anode, and in order to prevent a short circuit between the cathode and the anode at this portion.
[0010]
Note that FIG. 2 shows only the light-emitting elements formed in one pixel, but actually, an active matrix light-emitting device is formed by forming a plurality of these in the pixel portion.
[0011]
[Problems to be solved by the invention]
In the structure of the conventional light emitting device described above, the coefficient of thermal expansion is different from that of the anode (transparent conductive film) formed on the interlayer insulating film. When heat treatment is performed in such a structure in which materials having different coefficients of thermal expansion are in contact with each other, cracks are generated at the interface of a material having a small thermal expansion (in this case, an anode). The anode is an electrode that injects holes involved in light emission into the organic compound layer. If a crack occurs in the anode, the generation of holes is adversely affected, or the injected holes are reduced. Is considered to cause deterioration of the light emitting element itself. In addition, the unevenness of the anode surface may adversely affect the generation and injection of holes, the number of injected holes may be reduced, and this crack may be a cause of deterioration of the light emitting element itself.
[0012]
Furthermore, the organic compound layer has the property of being easily deteriorated by oxygen and moisture, but many of the organic resin materials such as polyimide, polyamide, and acrylic are used as an interlayer insulating film. There has been a problem that the light emitting element is deteriorated by a gas such as oxygen generated from the formed interlayer insulating film.
[0013]
Furthermore, alkali metal materials such as Al and Mg, which may give a fatal impact on the TFT characteristics, are used for the cathode material of the light emitting element. If alkali metal is mixed into the active layer of the TFT, the electrical characteristics of the TFT will fluctuate and reliability over time cannot be ensured.
[0014]
In order not to impair the characteristics of the TFT, by separating the TFT manufacturing process chamber (clean room) from the light emitting device manufacturing process chamber (clean room), the active layer of the TFT is not contaminated by alkali metal. It is preferable to make it. However, in order to prevent contamination by alkali metals, if the process includes the movement of a processing room (clean room), the TFT substrate is now contaminated with dust in the air, or the TFT element is destroyed by charging. The problem of being fooled will arise.
[0015]
Accordingly, it is an object of the present invention to manufacture a light-emitting element having a long lifetime that solves the above-described problems with a light-emitting element having a structure that is less likely to deteriorate than before, and to provide a high-quality light-emitting device and a manufacturing method thereof.
[0016]
[Means for solving the problems]
In the present invention, an interlayer insulating film is formed on a TFT formed on an insulator, an insulating film is formed on the interlayer insulating film, and an anode electrically connected to the TFT through a wiring is formed. Forming a resin insulating film covering the anode and the wiring, etching to form a bank, heat-treating, cleaning the anode, and forming an insulating film covering the anode and the bank; It is a feature.
[0017]
By forming an insulating film between the interlayer insulating film and the anode in this way, it is possible to reduce the occurrence of cracks that occur when heat treatment is performed in a state where a material having a coefficient of thermal expansion is in contact with light emission. This leads to longer life of the element. In addition, gas and moisture generated from the interlayer insulating film can be prevented from reaching the light emitting element. In addition to the inorganic insulating film, this insulating film may be a cured film formed by surface modification by plasma treatment or a DLC film.
[0018]
Furthermore, by wiping the anode, the unevenness of the anode surface can be flattened and dust on the anode surface can be removed.
[0019]
Further, by forming an insulating film covering the anode and the bank, an effect of adjusting the balance between the amount of holes and electrons injected into the organic compound layer can be expected.
[0020]
According to another aspect of the invention, after forming a resin insulating film for forming a bank, the resin insulating film is moved to a treatment chamber where contamination of alkali metal or the like can be avoided, and then the resin insulating film is etched. It is characterized by forming.
[0021]
After forming the insulating film for protecting the semiconductor film of the TFT in this way, an antistatic treatment is further performed to form a first processing chamber (first clean room) for forming the TFT substrate and a second light emitting element. By separating the processing chamber (second clean room), the risk of alkali metal mixing into the active layer of the TFT from an alkali metal material such as Al or Mg used for the cathode material of the light emitting element can be reduced. The electrical characteristics of the TFT and the reliability over time can be improved.
[0022]
For the antistatic film, a resin insulating film for forming a bank, a material that can be easily removed without affecting the anode and wiring are used. As such a material, a material having a degree of conductivity (10−8 [S / m]) necessary for preventing charging is suitable. In general, an organic conductor is used, and a conductive polymer is formed by a spin coating method, and a conductive low molecule is formed by a vapor deposition method or the like. Specifically, polyethylenedioxythiophene (abbreviation: PEDOT), polyaniline (abbreviation: PAni), glycerin fatty acid ester, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, N, N-bis (2-hydroxyethyl) Alkylamine [alkyldiethanolamine], N-2-hydroxyethyl-N-2 hydroxyalkylamine [hydroxyalkylmonoethanolamine], polyoxyethylene alkylamine, polyoxyethylene alkylamine fatty acid ester, alkyldiethanolamide, alkylsulfonate , Alkylbenzene sulfonate, alkyl phosphate, tetraalkylammonium salt, trialkylbenzylammonium salt, alkylbetaine, alkylimidazolium betaine, etc. It is. These materials can be easily removed with water or an organic solvent. Furthermore, an insulating material such as an organic insulator such as polyimide, acrylic, polyamide, polyimide amide, or BCB (benzocyclobutene) can also be used as the antistatic film. These antistatic films are applicable to all embodiments.
[0023]
Another aspect of the invention is characterized in that it includes a step of forming a bank and subjecting the bank surface to plasma treatment after crystallization by heat treatment of the anode.
[0024]
In this way, by performing a plasma treatment on the bank surface to form a cured film by modifying the surface, it is possible to prevent moisture from being released from the bank and deteriorating the light emitting element.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
A TFT 101 is formed on the substrate 100. The TFT shown here is a TFT for controlling the current flowing through the light emitting element, and is referred to as a current control TFT 101 in this specification (FIG. 1A).
[0026]
Next, an interlayer insulating film 102 is formed on the current control TFT 101 and planarized. As the interlayer insulating film 102, an organic resin material such as polyimide, acrylic, polyamide, polyimide amide, epoxy resin film, or BCB (benzocyclobutene) can be used, and the average film thickness is about 1.0 to 2.0 μm. Form. By forming the interlayer insulating film 102, planarization can be performed satisfactorily. Moreover, since an organic resin material generally has a low dielectric constant, parasitic capacitance can be reduced.
[0027]
Next, a first insulating film 103 is formed over the interlayer insulating film 102 so that degassing from the interlayer insulating film 102 does not adversely affect the light emitting element. The first insulating film 103 may be formed of an inorganic insulating film, typically a silicon oxide film, a silicon oxynitride film, a silicon nitride film, or a stacked film of a combination thereof, and a reaction pressure of 20 by plasma CVD. ~ 200Pa, substrate temperature 300 ~ 400 ° C, power density 0.1 ~ 1.0W / cm at high frequency (13.56MHz)²It is formed by discharging with. Alternatively, a plasma treatment may be performed on the surface of the interlayer insulating film to form a cured film containing one or more kinds of gas elements selected from hydrogen, nitrogen, halogenated carbon, hydrogen fluoride, or a rare gas.
[0028]
Thereafter, a resist mask having a desired pattern is formed, a contact hole reaching the drain region of the current control TFT 101 is formed, and a wiring 104 is formed. As a wiring material, an alloy metal other than Al and Ti as a conductive metal film may be used to form a film by a sputtering method or a vacuum evaporation method, and then patterned into a desired shape.
[0029]
Next, a transparent conductive film 105 to be an anode of the light emitting element is formed. The transparent conductive film 105 is typically formed using indium tin oxide (ITO) or a transparent conductive film in which indium oxide is mixed with 2 to 20% zinc oxide (ZnO).
[0030]
Subsequently, the transparent conductive film 105 is etched to form an anode. Thereafter, the bank 107 is formed and heat treatment is performed at 230 to 350 ° C. Note that in this specification, an insulating film having an opening on the anode and covering the end of the anode is referred to as a bank (FIGS. 1B and 1C).
[0031]
Next, the surface of the anode 106 is wiped with a cleaning liquid using a PVA (polyvinyl alcohol) -based porous material, and the surface of the anode 106 is flattened and dust and the like are removed. In the present specification, the process of wiping the anode surface with a PVA (polyvinyl alcohol) -based porous body and performing planarization and dust removal is referred to as wiping.
[0032]
After the surface of the anode is wiped, a second insulating film 110 is formed, and an organic compound layer 111 and a cathode 112 are formed on the second insulating film 110. The second insulating film 110 is formed of an organic resin insulating film such as polyimide, polyamide, or acrylic with a thickness of 1 to 5 nm by using a spin coating method.
[0033]
The organic compound layer 111 is formed by stacking a plurality of layers such as a hole injection layer, a hole transport layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a buffer layer in addition to the light emitting layer. The thickness of the organic compound layer 111 is preferably about 10 to 400 nm.
[0034]
The cathode 112 is formed by a vapor deposition method after the organic compound layer 111 is formed. As a material for the cathode 112, in addition to MgAg and Al—Li alloy (aluminum-lithium alloy), a film formed by co-evaporation with an element belonging to Group 1 or 2 of the periodic table and aluminum is used. Also good. The film thickness of the cathode 112 is preferably about 80 to 200 nm.
[0035]
Here, about the state of the surface of the transparent conductive film by performing a wiping process, the result of having observed the surface using an atomic force microscope (AFM: Atomic Force Microscope) is shown to FIGS.
[0036]
Note that, in the surface observation in this example, an ITO film formed with a film thickness of 110 nm on a glass substrate and crystallized by heat treatment at 250 ° C. is used as a measurement surface.
[0037]
14 and 15 show the uneven shape of the substrate surface observed by AFM. In addition, the result of having observed the measurement surface before a wiping process is shown in FIG. 14, and the result of having observed the measurement surface after a wiping process is shown in FIG.
[0038]
  FIG. 16 shows the average surface roughness (Ra) before and after the wiping treatment using Berglin (manufactured by Ozu Sangyo) as the PVA-based porous material for wiping. Here, the average surface roughness is a three-dimensional extension of the centerline average roughness defined in JIS B0601 so that it can be applied to the surface. From this result, it can be seen that after the wiping treatment, the average surface roughness on the measurement surface decreases and the flatness increases.Further, from the results of FIG. 16, it can be seen that the average surface roughness of the surface of the transparent conductive film is 0.9 nm or less (preferably 0.85 nm or less).
[0039]
【Example】
Example 1
In this example, a light-emitting element manufactured using the present invention will be described. Note that here, an example of a method for simultaneously manufacturing a pixel portion including the light-emitting element of the present invention over the same substrate and TFTs (n-channel TFT and p-channel TFT) of a driver circuit provided around the pixel portion is shown. It demonstrates using FIGS. 3-6.
[0040]
First, in this embodiment, a substrate 900 made of glass such as barium borosilicate glass represented by Corning # 7059 glass or # 1737 glass or aluminoborosilicate glass is used. Note that the substrate 900 is not limited as long as it is a light-transmitting substrate, and a quartz substrate may be used. Further, a plastic substrate having heat resistance that can withstand the processing temperature of this embodiment may be used.
[0041]
Next, as illustrated in FIG. 3A, a base insulating film 901 formed of an insulating film such as a silicon oxide film, a silicon nitride film, or a silicon oxynitride film is formed over the substrate 900. In this embodiment, a two-layer structure is used as the base insulating film 901; however, a single-layer film of the insulating film or a structure in which two or more layers are stacked may be used. As a first layer of the base insulating film 901, a plasma CVD method is used, and SiH_Four, NH_ThreeAnd N₂A silicon oxynitride film 901a formed using O as a reactive gas is formed to a thickness of 10 to 200 nm (preferably 50 to 100 nm). In this embodiment, a silicon oxynitride film 901a (composition ratio Si = 32%, O = 27%, N = 24%, H = 17%) having a thickness of 50 nm is formed. Next, as a second layer of the base insulating film 901, a plasma CVD method is used, and SiH_FourAnd N₂A silicon oxynitride film 901b formed using O as a reactive gas is stacked to a thickness of 50 to 200 nm (preferably 100 to 150 nm). In this embodiment, a silicon oxynitride film 901b (composition ratio Si = 32%, O = 59%, N = 7%, H = 2%) having a thickness of 100 nm is formed.
[0042]
Next, semiconductor layers 902 to 905 are formed over the base insulating film 901. The semiconductor layers 902 to 905 are formed by forming a semiconductor film having an amorphous structure by a known means (sputtering method, LPCVD method, plasma CVD method, or the like), and then known crystallization treatment (laser crystallization method, heat A crystalline semiconductor film obtained by performing a crystallization method or a thermal crystallization method using a catalyst such as nickel) is formed by patterning into a desired shape. The semiconductor layers 902 to 905 are formed with a thickness of 25 to 80 nm (preferably 30 to 60 nm). The material of the crystalline semiconductor film is not limited, but is preferably silicon (silicon) or silicon germanium (Si_XGe_1-X(X = 0.0001 to 0.02)) It may be formed of an alloy or the like. In this example, a 55 nm amorphous silicon film was formed by plasma CVD, and then a solution containing nickel was held on the amorphous silicon film. This amorphous silicon film is dehydrogenated (500 ° C., 1 hour), then thermally crystallized (550 ° C., 4 hours), and further laser annealed to improve crystallization. Thus, a crystalline silicon film was formed. Then, semiconductor layers 902 to 905 were formed by patterning the crystalline silicon film using a photolithography method.
[0043]
Further, after the semiconductor layers 902 to 905 are formed, the semiconductor layers 902 to 905 may be doped with a small amount of impurity elements (boron or phosphorus) in order to control the threshold value of the TFT.
[0044]
When a crystalline semiconductor film is formed by laser crystallization, a pulse oscillation type or continuous emission type excimer laser, YAG laser, YVO_FourA 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, but when an excimer laser is used, the pulse oscillation frequency is 300 Hz and the laser energy density is 100 to 400 mJ / cm.²(Typically 200-300mJ / cm²). When a YAG laser is used, the second harmonic is used and the pulse oscillation frequency is set to 30 to 300 kHz, and the laser energy density is set to 300 to 600 mJ / cm.²(Typically 350-500mJ / cm²) 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 50 to 90%. Good.
[0045]
Next, a gate insulating film 906 that covers the semiconductor layers 902 to 905 is formed. The gate insulating film 906 is formed of an insulating film containing silicon with a thickness of 40 to 150 nm by 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%) with a thickness of 110 nm is formed 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.
[0046]
When a silicon oxide film is used, TEOS (Tetraethyl Orthosilicate) and O₂The reaction pressure is 40 Pa, the substrate temperature is 300 to 400 ° C., and the high frequency (13.56 MHz) power density is 0.5 to 0.8 W / cm.²And can be formed by discharging. The silicon oxide film thus manufactured can obtain good characteristics as a gate insulating film by thermal annealing at 400 to 500 ° C. thereafter.
[0047]
Then, a heat-resistant conductive layer 907 for forming a gate electrode is formed over the gate insulating film 906 with a thickness of 200 to 400 nm (preferably 250 to 350 nm). The heat-resistant conductive layer 907 may be formed as a single layer, or may have a laminated structure including a plurality of layers such as two layers or three layers as necessary. The heat resistant conductive layer includes an element selected from Ta, Ti, and W, an alloy containing the element as a component, or an alloy film combining the elements. These heat-resistant conductive layers are formed by a sputtering method or a CVD method, and it is preferable to reduce the concentration of impurities contained in order to reduce the resistance. Particularly, the oxygen concentration is preferably 30 ppm or less. In this embodiment, the W film is formed with a thickness of 300 nm. The W film may be formed by sputtering using W as a target, or tungsten hexafluoride (WF₆Can also be formed by a thermal CVD method. In any case, in order to use as a gate electrode, it is necessary to reduce the resistance, and the resistivity of the W film is desirably 20 μΩcm or less. The resistivity of the W film can be reduced by increasing the crystal grains. However, when there are many impurity elements such as oxygen in W, crystallization is hindered and the resistance is increased. Therefore, when sputtering is used, a W target having a purity of 99.9 to 99.9999% is used, and a W film is formed with sufficient consideration so that impurities are not mixed in the gas phase during film formation. Thus, a resistivity of 9 to 20 μΩcm can be realized.
[0048]
On the other hand, when a Ta film is used for the heat-resistant conductive layer 907, it can be similarly formed by sputtering. The Ta film uses Ar as a sputtering gas. In addition, when an appropriate amount of Xe or Kr is added to the gas during sputtering, the internal stress of the film to be formed can be relaxed and the film can be prevented from peeling. The resistivity of the α-phase Ta film is about 20 μΩcm and can be used as a gate electrode, but the resistivity of the β-phase Ta film is about 180 μΩcm and is not suitable for a gate electrode. Since the TaN film has a crystal structure close to an α phase, an α phase Ta film can be easily obtained by forming a TaN film under the Ta film. Although not shown, it is effective to form a silicon film doped with phosphorus (P) with a thickness of about 2 to 20 nm under the heat-resistant conductive layer 907. This improves adhesion and prevents oxidation of the conductive film formed thereon, and at the same time, the alkali metal element present in a trace amount in the heat-resistant conductive layers 907 and 908 has the first shape gate insulating film. The diffusion to 906 can be prevented. In any case, the heat resistant conductive layer 907 preferably has a resistivity in the range of 10 to 50 μΩcm.
[0049]
In this example, a TaN film was formed on the first conductive layer (first conductive film 907), and a W film was formed on the second conductive layer (second conductive film 908) (FIG. 3A). ).
[0050]
Next, a resist mask 909 is formed using a photolithography technique. Then, a first etching process is performed. The first etching process is performed under the first etching condition and the second etching condition.
[0051]
In this embodiment, an ICP etching apparatus is used, and the etching gas is Cl.₂And CF_FourO₂Each gas flow ratio is 25/25/10, and 3.2 W / cm at a pressure of 1 Pa.²RF (13.56 MHz) power is applied to form plasma. 224 mW / cm also on the substrate side (sample stage)²RF (13.56 MHz) power is applied, thereby applying a substantially negative self-bias voltage. The W film is etched under the first etching condition. Subsequently, without removing the resist mask, the etching gas is changed to the second etching condition and the CF is changed to the etching gas._FourAnd Cl₂Each gas flow rate ratio is set to 30/30 sccm, and RF (13.56 MHz) power is applied at a pressure of 1 Pa to form plasma. 20 W RF (13.56 MHz) power is also applied to the substrate side (sample stage), and a substantially negative self-bias voltage is applied.
[0052]
Conductive layers 910 to 913 having a first tapered shape are formed by the first etching process. The angle of the tapered portion of the conductive layers 910 to 913 is formed to be 15 to 30 °. In order to perform etching without leaving a residue, overetching that increases the etching time at a rate of about 10 to 20% is performed. Since the selection ratio of the silicon oxynitride film (gate insulating film 906) to the W film is 2 to 4 (typically 3), the surface on which the silicon oxynitride film is exposed is etched by about 20 to 50 nm by overetching. (FIG. 3B).
[0053]
Then, a first doping process is performed to add an impurity element of one conductivity type to the semiconductor layer. Here, an impurity element addition step for imparting n-type is performed without removing the resist mask 909. Impurities are added to part of the semiconductor layers 902 to 905 in a self-aligning manner using the first conductive films 910 to 913 as masks to form first n-type impurity regions 914 to 917. As an impurity element imparting n-type, an element belonging to Group 15, typically phosphorus (P) or arsenic (As) is used. Here, phosphorus (P) is used, and the first n-type impurity is formed by ion doping. The region 914-917 has 1 × 10²⁰~ 1x10^{twenty one}attoms / cm^ThreeAn impurity element imparting n-type is added in a concentration range of (Figure 3B).
[0054]
Next, a second etching process is performed without removing the resist mask. The second etching process is performed under the third etching condition and the fourth etching condition. Similarly to the first etching process, the second etching process is also performed by an ICP etching apparatus, and the etching gas is CF._FourAnd Cl₂Each gas flow rate ratio is 30/30 sccm and RF (13.56 MHz) power is applied at a pressure of 1 Pa to form plasma. 20 W RF (13.56 MHz) power is also applied to the substrate side (sample stage), and a substantially negative self-bias voltage is applied. Under the third etching conditions, conductive films 918 to 921 etched to the same extent as the W film and the TaN film are formed (FIG. 3C).
[0055]
Thereafter, the resist mask is changed to the fourth etching condition as it is, and the etching gas is changed to CF._FourAnd Cl₂And O₂The mixed gas is used and RF power (13.56 MHz) power is applied at a pressure of 1 Pa to form plasma. 20 W RF (13.56 MHz) power is also applied to the substrate side (sample stage), and a substantially negative self-bias voltage is applied. The W film is etched under the fourth etching conditions to form second shape conductive films 922 to 925 (FIG. 3D).
[0056]
Next, a second doping step (addition of an n-type impurity element to the semiconductor layer through the first shape conductive films 922a to 925a) is performed, and a channel in contact with the first n-type impurity regions 914 to 917 is obtained. Second n-type impurity regions 926 to 929 are formed on the formation region side. The impurity concentration in the second n-type impurity region is 1 × 10¹⁶~ 1x10¹⁹atoms / cm^ThreeTo be. In this second doping step, the conditions are such that an n-type impurity element is added to the semiconductor layer even through the tapered portions of the second shape conductive films 922a to 925a of the first layer. In the specification, the second n-type impurity region overlapping the first-layer second-shaped conductive films 922a to 925a is defined as the Lov (ov is overlapped) region, the first-layer second-shaped conductive layer. The second n-type impurity region that does not overlap with the films 922a to 925a is referred to as Loff (off means offset) (FIG. 4A).
[0057]
Next, as shown in FIG. 4B, impurity regions 932 (932a, 932b) and 933 (conductivity type opposite to one conductivity type are formed in the semiconductor layers 902 and 905 to be active layers of the later p-channel TFT. 933a, 933b). Also in this case, an impurity element imparting p-type conductivity is added using the second shape conductive layers 922 and 925 as a mask, and impurity regions are formed in a self-aligning manner. At this time, the semiconductor layers 903 and 904 to be active layers of the later n-channel TFT are formed by forming masks 930 and 931 made of resist and covering the entire surface. The p-type impurity regions 932 and 933 formed here are diborane (B₂H₆) And the concentration of the impurity element imparting p-type in the p-type impurity regions 932 and 933 is 2 × 10²⁰~ 2x10^{twenty one}atoms / cm^ThreeTo be.
[0058]
The p-type impurity regions 932 and 933 contain an impurity element imparting n-type in detail, but the concentration of the impurity element imparting p-type in these impurity regions 932 and 933 imparts n-type. By adding the impurity element so as to be 1.5 to 3 times the concentration of the impurity element, the p-type impurity region functions as a source region and a drain region of the p-channel TFT, so that no problem occurs.
[0059]
After that, as illustrated in FIG. 4C, a first interlayer insulating film 934 is formed over the conductive layers 922 to 925 having the second shape and the gate insulating film 906. The first interlayer insulating film 934 may be formed using a silicon oxide film, a silicon oxynitride film, a silicon nitride film, or a stacked film in which these are combined. In any case, the first interlayer insulating film 934 is formed of an inorganic insulating material. The thickness of the first interlayer insulating film 934 is 100 to 200 nm. In the case where a silicon oxide film is used as the first interlayer insulating film 934, TEOS and O₂The reaction pressure is 40 Pa, the substrate temperature is 300 to 400 ° C., and the high frequency (13.56 MHz) power density is 0.5 to 0.8 W / cm.²And can be formed by discharging. In the case where a silicon oxynitride film is used as the first interlayer insulating film 934, SiH is formed by plasma CVD._Four, N₂O, NH_ThreeSilicon oxynitride film manufactured from SiH or SiH_Four, N₂A silicon oxynitride film formed from O may be used. The production conditions in this case are a reaction pressure of 20 to 200 Pa, a substrate temperature of 300 to 400 ° C., and a high frequency (60 MHz) power density of 0.1 to 1.0 W / cm.²Can be formed. Further, as the first interlayer insulating film 934, SiH_Four, N₂O, H₂Alternatively, a silicon oxynitride silicon film manufactured from the above may be used. Similarly, the silicon nitride film is made of SiH by plasma CVD._Four, NH_ThreeIt is possible to make from.
[0060]
Then, a step of activating the impurity element imparting n-type or p-type added at each concentration is performed. This step is performed by a thermal annealing method using a furnace annealing furnace. In addition, a laser annealing method or a rapid thermal annealing method (RTA method) can be applied. In the thermal annealing method, the oxygen concentration is 1 ppm or less, preferably 0.1 ppm or less in a nitrogen atmosphere at 400 to 700 ° C., typically 500 to 600 ° C. In this example, the temperature is 550 ° C. for 4 hours. Heat treatment was performed. In addition, when a plastic substrate having a low heat resistant temperature is used for the substrate 900, it is preferable to apply a laser annealing method.
[0061]
In this heat treatment step, the catalyst element (nickel) used in the step of crystallizing the semiconductor layer was added with a high concentration of an element belonging to Group 15 of the periodic table having gettering action (phosphorus in this embodiment). By moving (gettering) to the first n-type impurity region, the concentration of the catalytic element in the channel formation region can be reduced.
[0062]
Subsequent to the activation step, the step of hydrogenating the semiconductor layer is performed by changing the atmosphere gas and performing heat treatment at 300 to 450 ° C. for 1 to 12 hours in an atmosphere containing 3 to 100% hydrogen. This step is performed in the semiconductor layer by thermally excited hydrogen.¹⁶-10¹⁸/ Cm^ThreeThis is a step of terminating the dangling bond. As another means of hydrogenation, plasma hydrogenation (using hydrogen excited by plasma) may be performed. In any case, the defect density in the semiconductor layers 902 to 905 is 10¹⁶/ Cm^ThreeIt is desirable to set it as follows, and for that purpose, hydrogen may be added in an amount of about 0.01 to 0.1 atomic%.
[0063]
Then, a second interlayer insulating film 935 made of an organic insulating material is formed with an average film thickness of 1.0 to 2.0 μm. As the organic resin material, polyimide, acrylic, polyamide, polyimide amide, BCB (benzocyclobutene), or the like can be used. For example, when using a type of polyimide that is thermally polymerized after being applied to the substrate, it is formed by baking at 300 ° C. in a clean oven. When acrylic is used, a two-component type is used, and after mixing the main material and the curing agent, applying the entire surface of the substrate using a spinner, preheating at 80 ° C. for 60 seconds with a hot plate. It can be formed by baking at 250 ° C. for 60 minutes in a clean oven.
[0064]
Thus, the surface can be satisfactorily planarized by forming the second interlayer insulating film 935 from an organic insulating material. Moreover, since the organic resin material generally has a low dielectric constant, parasitic capacitance can be reduced. However, since it is hygroscopic and not suitable as a protective film, it is preferably used in combination with a silicon oxide film, a silicon oxynitride film, a silicon nitride film, or the like formed as the first interlayer insulating film 934 as in this embodiment. .
[0065]
By the way, the second interlayer insulating film 935 formed using an organic insulating material may generate moisture and gas. It is known that a light emitting element is easily deteriorated by moisture or gas (oxygen). The heat generated when a light-emitting device actually formed using an organic resin insulating film as an interlayer insulating film is used, moisture and gas are generated from the organic resin insulating film, and the light emitting element is likely to be deteriorated. It is possible. Therefore, a first insulating film 936 is formed over the second interlayer insulating film 935 formed of an organic insulating material.
Note that the first insulating film 936 is formed using a silicon oxide film, a silicon oxynitride film, a silicon nitride film, or the like. Note that the first insulating film 936 formed here may be formed by a sputtering method or a plasma CVD method. The first insulating film 936 may be formed after the contact hole is formed.
[0066]
Thereafter, a resist mask having a predetermined pattern is formed, and contact holes are formed in the respective semiconductor layers to reach impurity regions serving as source regions or drain regions. The contact hole is formed by a dry etching method. In this case, CF is used as an etching gas._Four, O₂The first insulating film 936 is first etched using a mixed gas of_Four, O₂, The second interlayer insulating film 935 made of an organic resin material is etched using a mixed gas of He, and then the etching gas is changed to CF again._Four, O₂The first interlayer insulating film 934 is etched as follows. Further, in order to increase the selectivity with the semiconductor layer, the etching gas is changed to CHF._ThreeThe contact hole can be formed by etching the gate insulating film 906 while switching to.
[0067]
Then, a conductive metal film is formed by sputtering or vacuum vapor deposition, patterned with a mask, and then etched to form wirings 937 to 943. Although not shown, in this embodiment, this wiring is formed by a laminated film of a Ti film having a thickness of 50 nm and an alloy film (alloy film of Al and Ti) having a thickness of 500 nm.
[0068]
Next, a transparent conductive film is formed thereover with a thickness of 80 to 120 nm and etched to form an anode 944 (FIG. 5A). In this embodiment, an indium tin oxide (ITO) film or a transparent conductive film in which 2 to 20% zinc oxide (ZnO) is mixed with indium oxide is used as the transparent electrode.
[0069]
Further, the anode 944 is formed in contact with the drain wiring 943 so as to be electrically connected to the drain region of the current control TFT (FIG. 5A). Here, heat treatment may be performed on the anode 944 at 180 to 350 ° C.
[0070]
Next, as illustrated in FIG. 5B, a third interlayer insulating film 945 is formed over the anode 944. Here, the process chamber (clean room) may be moved to form a light emitting element. An extremely thin film (hereinafter referred to as an antistatic film) 946 having an antistatic effect is formed on the third interlayer insulating film 945 so that the TFT substrate is not contaminated or destroyed by dust in the air. The antistatic film 946 is formed of a material that can be removed by washing with water (FIG. 5C). In addition to forming the antistatic film, the film may be stored in a transfer case that can be antistatic. Furthermore, before moving the processing chamber, an operation inspection of the TFT substrate formed in the steps so far may be performed.
[0071]
When the TFT substrate is brought into a processing chamber (clean room) for forming a light emitting element, the antistatic film 946 is removed by washing with water, and the third interlayer insulating film 945 is etched to a position corresponding to the pixel (light emitting element). A bank 947 having an opening is formed. In this embodiment, the bank 947 is formed using a resist. In this embodiment, the thickness of the bank 947 is set to about 1 μm, and a region covering a portion where the wiring and the anode are in contact with each other is formed in a tapered shape (FIG. 6A). Note that when the light-emitting element is carried into the processing chamber, an inspection for confirming the operation of the moved TFT substrate may be performed again.
[0072]
In this embodiment, a film made of a resist is used as the bank 947, but polyimide, polyamide, acrylic, BCB (benzocyclobutene), a silicon oxide film, or the like can be used depending on circumstances. The bank 947 may be either an organic substance or an inorganic substance as long as it has an insulating property. However, when the bank 947 is formed using photosensitive acrylic, the photosensitive acrylic film is etched and heated at 180 to 350 ° C. It is preferable to carry out the treatment. In the case of forming using a non-photosensitive acrylic film, it is preferable to form a bank by etching after performing a heat treatment at 180 to 350 ° C.
[0073]
Next, a wiping process is performed on the anode surface. Note that in this embodiment, the surface of the anode 944 is wiped with Berglin (manufactured by Ozu Sangyo) to flatten the surface of the anode 944 and remove dust attached to the surface. As the cleaning liquid for wiping, pure water is used, the rotational speed of the shaft around which the Berulin is wound is 100 to 300 rpm, and the indentation value is 0.1 to 1.0 mm (FIG. 6A).
[0074]
Next, the TFT substrate is vacuum baked. In order to release moisture and gas from the resin insulating film for forming the bank, vacuum exhaust is performed at a certain degree of vacuum (for example, 0.01 Torr or less). Note that the vacuum baking may be performed after washing the antistatic film with water, after wiping the anode, or before forming the light emitting element.
[0075]
Next, a second insulating film 948 is formed so as to cover the bank 947 and the anode 944. The second insulating film 948 is formed using an organic resin film such as polyimide, polyamide, or polyimideamide with a film thickness of 1 to 5 nm by a spin coating method, an evaporation method, a sputtering method, or the like. By forming this insulating film, cracks and the like on the surface of the anode 944 can be covered, and deterioration of the light-emitting element can be prevented.
[0076]
Next, an organic compound layer 949 and a cathode 950 are formed over the second insulating film 948 by an evaporation method. In this embodiment, the MgAg electrode is used as the cathode of the light emitting element, but other known materials may be used. Note that the organic compound layer 949 is formed by stacking a plurality of layers such as a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and a buffer layer in addition to the light-emitting layer. The structure of the organic compound layer used in this example will be described in detail below.
[0077]
In this embodiment, copper phthalocyanine is used as the hole injection layer, and α-NPD is used as the hole transport layer by vapor deposition.
[0078]
Next, a light emitting layer is formed. In this embodiment, an organic compound layer showing different light emission is formed by using different materials for the light emitting layer. In this embodiment, an organic compound layer that emits red, green, and blue light is formed. Moreover, since vapor deposition is used as a film formation method, a light emitting layer can be formed using a different material for each pixel by using a metal mask at the time of film formation.
[0079]
The light emitting layer that develops red color is Alq._ThreeIt is formed using a material doped with DCM. In addition, (1,10-phenanthroline) tris (1,3-diphenyl-propane-) which is an Eu complex with N, N′-disalicylidene-1,6-hexanediaminato) zinc (II) (Zn (salhn)) 1,3-Dionato) Europium (III) (Eu (DBM)_ThreeA material doped with (Phen) can be used, but other known materials can also be used.
[0080]
In addition, the light-emitting layer that develops green color is CBP and Ir (ppy)_ThreeCan be formed by a co-evaporation method. At this time, it is preferable to laminate the hole blocking layer using BCP. In addition, aluminum quinolinato complex (Alq_Three), A benzoquinolinolatoberyllium complex (BeBq) can be used. Furthermore, quinolinato aluminum complex (Alq_Three) Using a material such as coumarin 6 or quinacridone as a dopant is also possible, but other known materials can also be used.
[0081]
Further, the light emitting layer that develops a blue color is composed of DPVBi, which is a distyryl derivative, and N, N′-disalicylidene-1,6-hexanediaminato) zinc (II) (Zn), which is a zinc complex having an azomethine compound as a ligand. (Salhn)) and 4,4′-bis (2,2-diphenyl-vinyl) -biphenyl (DPVBi) doped with perylene may be used, but other known materials may also be used.
[0082]
Next, an electron transport layer is formed. For the electron transport layer, a material such as a 1,3,4-oxadiazole derivative or a 1,2,4-triazole derivative (TAZ) can be used. In this embodiment, 1,2,4- It forms with a film thickness of 30-60 nm by a vapor deposition method using a triazole derivative (TAZ).
[0083]
Thus, an organic compound layer having a laminated structure is formed. Note that the thickness of the organic compound layer 949 in this embodiment may be 10 to 400 nm (typically 60 to 150 nm), and the thickness of the cathode 950 may be 80 to 200 nm (typically 100 to 150 nm).
[0084]
After the organic compound layer is formed, the cathode 950 of the light emitting element is formed by a vapor deposition method. In this embodiment, MgAg is used as the conductive film serving as the cathode of the light-emitting element. However, an Al—Li alloy film (alloy film of aluminum and lithium), an element belonging to Group 1 or 2 of the periodic table, and aluminum It is also possible to use a film formed by co-evaporation.
[0085]
In this way, a light emitting device having a structure as shown in FIG. 6B is completed. Note that a portion 951 where the anode 944, the organic compound layer 949, and the cathode 950 are stacked is referred to as a light-emitting element.
[0086]
A p-channel TFT 1000 and an n-channel TFT 1001 are TFTs of a driving circuit and form a CMOS. The switching TFT 1002 and the current control TFT 1003 are TFTs of the pixel portion, and the TFT of the driver circuit and the TFT of the pixel portion can be formed on the same substrate.
[0087]
Note that in the case of a light-emitting device using a light-emitting element, the power supply voltage of the drive circuit is about 5 to 6 V, and the maximum is about 10 V. Therefore, deterioration due to hot electrons in the TFT is not a problem.
[0088]
(Example 2)
A process for manufacturing the light-emitting device will be described with reference to FIGS.
[0089]
In accordance with Embodiment 1, the steps up to the step of forming two conductive films 907 and 908 over the gate insulating film 906 as shown in FIG.
[0090]
Next, a step of forming the first tapered conductive layers 3901 to 3904 by etching the conductive films 907 and 908 using the masks 909a to 909 will be described with reference to FIG. For the etching, an ICP (Inductively Coupled Plasma) etching method is used. Although there is no limitation on the etching gas, CF for etching W film or tantalum nitride film_FourAnd Cl₂And O₂And are used. Etching is performed by setting each gas flow rate to 25/25/10 and applying 500 W of RF (13.56 MHz) power to the coil electrode at a pressure of 1 Pa. In this case, 150 W RF (13.56 MHz) power is also applied to the substrate side (sample stage), and a substantially negative self-bias voltage is applied. Under this first etching condition, the W film is mainly etched into a predetermined shape.
[0091]
After this, the etching gas is CF_FourAnd Cl₂The gas flow ratio is changed to 30/30, and 500 W of RF (13.56 MHz) power is applied to the coil-type electrode at a pressure of 1 Pa to generate plasma and perform etching for about 30 seconds. . 20 W RF (13.56 MHz) power is also applied to the substrate side (sample stage), and a substantially negative self-bias voltage is applied. CF_FourAnd Cl₂The tantalum nitride film and the W film are etched at a similar rate. Thus, the conductive layers 3901 to 3904 having the first tapered shape are formed. The taper is formed at 45 to 75 °. In order to perform etching without leaving a residue on the second insulating film, it is preferable to increase the etching time at a rate of about 10 to 20%. Note that a region of the gate insulating film 906 that is not covered with the first tapered conductive layers 3901 to 3904 is etched by about 20 to 50 nm to form a thinned region (FIG. 20A).
[0092]
Subsequently, a second etching process is performed as shown in FIG. 20B without removing the masks 909a to 909d. CF as etching gas_FourAnd Cl₂And O₂The gas flow ratio is 20/20/20, and 500 W of RF (13.56 MHz) power is applied to the coil-type electrode at a pressure of 1 Pa to generate plasma and perform etching. 20 W RF (13.56 MHz) power is applied to the substrate side (sample stage), and a lower self-bias voltage is applied than in the first etching process. Under this etching condition, the W film used as the second conductive film is etched. Thus, second tapered conductive layers 3905 to 3908 are formed. The surface of the region of the gate insulating film 906 that is not covered with the second tapered conductive layers 3905 to 3908 is etched and thinned by about 20 to 50 nm.
[0093]
After the resist mask is removed, a first doping process is performed in which an impurity element imparting n-type (n-type impurity element) is added to the semiconductor layer. The first doping process is performed by an ion doping method in which ions are implanted without mass separation. Doping is performed using the second tapered conductive films 3905 to 3908 as a mask and phosphine (PH) diluted with hydrogen._Three) Using a phosphine gas diluted with a gas or a rare gas, n-type impurity regions 3909 to 3912 containing an n-type impurity element having a first concentration are formed in the semiconductor layers 902 to 905. The phosphorus concentration of n-type impurity regions 3909 to 3912 containing the first concentration of n-type impurity element formed by this doping is 1 × 10¹⁶~ 1x10¹⁷/ Cm^Three(FIG. 20C).
[0094]
After that, first masks 3913 and 3915 that cover the entire semiconductor layers 902 and 905, a second tapered conductive layer 3907 over the semiconductor layer 904, and a second mask 3914 that covers a part of the semiconductor layer 904 are formed. Then, a second doping process is performed. In the second doping treatment, the n-type impurity region 3917 including the second concentration n-type impurity element and the n-type impurity element including the third concentration n-type impurity element are added to the semiconductor layer 903 through the second tapered conductive layer 3906a. Type impurity regions 3916 and 3918 are formed. The phosphorus concentration of the n-type impurity region 3917 containing the second concentration of n-type impurity element formed by this doping is 1 × 10¹⁷~ 1x10¹⁹/ Cm^ThreeThe phosphorus concentration of the n-type impurity regions 3916 and 3918 containing the third concentration of the n-type impurity element is 1 × 10²⁰~ 1x10^{twenty one}/ Cm^Three(FIG. 20D).
[0095]
In this embodiment, the n-type impurity region containing the second concentration n-type impurity element and the n-type impurity region containing the third concentration n-type impurity element are formed in one doping step as described above. Although it is formed, the impurity element may be added in two doping steps.
[0096]
Next, as shown in FIG. 21A, masks 3919 and 3920 that cover the semiconductor layers 903 and 904 are formed, and a third doping process is performed. Doping is hydrogen diluted diborane (B₂H₆) Using a diborane gas diluted with a gas or a rare gas, the semiconductor layers 902 and 905 include p-type impurity regions 3921 and 3923 containing a p-type impurity element at a first concentration and a p-type containing a p-type impurity element at a second concentration. Impurity regions 3922 and 3924 are formed. The p-type impurity regions 3921 and 3923 containing the first concentration of the p-type impurity element are 2 × 10²⁰~ 3x10^{twenty one}/ Cm^ThreeThe p-type impurity regions 3922 and 3924 that contain boron in the concentration range and contain the second concentration of the p-type impurity element are formed in regions overlapping the second tapered conductive layers 3905a and 3908a. 1 × 10¹⁸~ 1x10²⁰/ Cm^ThreeContains boron in a concentration range of.
[0097]
Next, as shown in FIG. 21B, a first interlayer insulating film 3925 made of a silicon nitride film or a silicon nitride oxide film is formed to a thickness of 50 nm by plasma CVD, and added to each semiconductor layer. In order to activate the impurity element, heat treatment is performed at 410 ° C. using a furnace. Through this heat treatment, the semiconductor film is also hydrogenated with hydrogen released from the silicon nitride film or the silicon nitride oxide film.
[0098]
Note that the heat treatment may be a heat treatment method using RTA (including an RTA method using gas or light as a heat source) in addition to a method using a furnace. In the case of performing heat treatment using a furnace, an insulating film that covers the gate electrode and the gate insulating film is formed before the heat treatment in order to prevent oxidation of the conductive film that forms the gate electrode, or the atmosphere during the heat treatment is changed. A reduced-pressure nitrogen atmosphere may be used. Alternatively, the semiconductor layer may be irradiated with the second harmonic (532 nm) light of the YAG laser. As described above, since there are several methods for activating the impurity element added to the semiconductor layer, the method may be determined as appropriate by the practitioner.
[0099]
Next, a second interlayer insulating film 3926 is formed using acrylic on the first interlayer insulating film 3925. Then, a silicon nitride film is formed over the second interlayer insulating film 3926 by a sputtering method to form a first insulating film (hereinafter also referred to as a barrier insulating film) 3927 for protecting the TFT from impurities. (FIG. 21C).
[0100]
Subsequently, a transparent conductive film is formed to a thickness of 80 to 120 nm over the barrier insulating film 3927 and etched to form an anode 3928 (FIG. 22A). In the present embodiment, an indium tin oxide (ITO) film or a transparent conductive film in which 2 to 20% zinc oxide (ZnO) is mixed with indium oxide is used as the transparent electrode.
[0101]
After that, a resist mask having a predetermined pattern is formed, and contact holes reaching impurity regions 3916, 3918, 3921, and 3923 which are source regions or drain regions formed in the respective semiconductor layers are formed. The contact hole may be formed by a dry etching method.
[0102]
Then, a conductive metal film is formed by a sputtering method or a vacuum vapor deposition method, patterned with a mask, and then etched to form wirings 3929 to 3935. Although not shown, in this embodiment, this wiring is formed by a laminated film of a Ti film having a thickness of 50 nm and an alloy film (alloy film of Al and Ti) having a thickness of 500 nm.
[0103]
Next, a third interlayer insulating film 3936 that covers the anode 3928 and the wirings 3929 to 3935 is formed. Here, in order to reduce the risk of alkali metal being mixed into the active layer of the TFT from alkali metal materials such as Al and Mg used for the cathode material of the light emitting element, a processing chamber (hereinafter referred to as a TFT substrate) is formed. Assume that the manufacturing process is advanced by moving the substrate from a first clean room to a processing chamber for forming a light emitting element (hereinafter referred to as a second clean room).
[0104]
An extremely thin film (hereinafter referred to as an antistatic film) having an antistatic action on the third interlayer insulating film 3936 so that the TFT substrate is not contaminated by dust in the air while moving or is not electrostatically damaged by static electricity. 3937). Note that the antistatic film 3937 may be formed of a material that can be easily removed, such as water washing (FIG. 22A). Alternatively, it is stored and moved in a case that can prevent destruction due to charging. Note that the operation of the TFT substrate formed through the steps up to here may be inspected before the processing chamber is moved. The above process is a process in the first process chamber (clean room) shown in the flowchart of FIG.
[0105]
The movement from the first processing chamber to the second processing chamber is, for example, movement within a building provided in the same site, or between factories (processing chambers, for example, clean rooms) dotted with the same corporation. Movement or a movement of a factory (processing room, for example, a clean room) between different legal persons is conceivable. In either case, the TFT substrate is moved so as not to be damaged.
[0106]
Subsequently, processing in the second processing chamber (clean room) shown in the flowchart of FIG. 19 is performed. When the TFT substrate is carried into the second processing chamber (clean room), the antistatic film 3937 is removed by washing with water, the third interlayer insulating film 3936 is etched, and an opening is formed at a position corresponding to the pixel (light emitting element). A bank 3938 is formed which covers a portion where the wiring 3934 and the anode 3928 are in contact with each other and an end portion of the anode 3928 in a tapered shape. In this embodiment, the thickness is about 1 μm, and the bank 3938 is formed using a resist. Here, an inspection for confirming the operation of the TFT substrate moved to the second processing chamber may be performed again.
[0107]
Next, the TFT substrate is vacuum baked. In order to release moisture and gas from the resin insulating film for forming the bank, vacuum exhaust is performed at a certain degree of vacuum (for example, 0.01 Torr or less). Note that the vacuum baking may be performed after washing the antistatic film with water, after wiping the anode, or before forming the EL element.
[0108]
Subsequently, in order to suppress deterioration of the light emitting element due to generation of moisture or gas from the bank 3938, the surface of the bank 3938 is covered with a second insulating film 3939, for example, with a silicon nitride film or the like. The second insulating film 3939 is also referred to as a second barrier insulating film 3939 because the second insulating film 3939 is an insulating film for protecting against moisture and gas which causes deterioration of the light emitting element.
[0109]
Subsequently, an organic compound layer 3940 is formed over the second insulating film 3939 so as to be in contact with the anode 3928, and a cathode 3951 is formed over the organic compound layer 3940 by an evaporation method. In this embodiment, the MgAg electrode is used as the cathode of the light emitting element, but other known materials may be used. Note that the organic compound layer 3940 may be stacked by combining a plurality of layers such as a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and a buffer layer in addition to the light-emitting layer. It may be formed according to Example 1.
[0110]
In this way, a light emitting device having a structure as shown in FIG. 22B is completed. Note that a portion 3942 stacked with the anode 3928, the organic compound layer 3940, and the cathode 3941 is referred to as a light-emitting element.
[0111]
As described above, by making the first processing chamber (for example, the first clean room) for forming the TFT substrate different from the second processing chamber (for example, the second clean room) for forming the light emitting element, The active layer of the TFT can be protected from alkali metal materials such as Al and Mg used for the cathode material of the light emitting element, and a favorable light emitting device can be provided.
[0112]
(Example 3)
According to Example 1 or Example 2, the layers up to the second interlayer insulating film (935, 3926) are formed. Next, a method for modifying the surface of the second interlayer insulating film (935, 3926) by performing plasma treatment on the second interlayer insulating film instead of forming the first insulating film 936 in Embodiment 1 is shown in FIG. I will explain it.
[0113]
For example, the second interlayer insulating film (935, 3926) is in one or a plurality of gases selected from hydrogen, nitrogen, hydrocarbon, halogenated carbon, hydrogen fluoride, or a rare gas (Ar, He, Ne, etc.). By performing a plasma treatment on the second interlayer insulating film (935, 3926), a new film is formed on the surface, or the type of the functional group existing on the surface is changed, so that the second interlayer insulating film ( 935, 3926). On the surface of the second interlayer insulating film (935, 3926), a dense film 935B is formed as shown in FIG. In this specification, this film is referred to as a cured film 935B. Thereby, it is possible to prevent gas and moisture from being released from the organic resin film.
[0114]
Further, since the anode (ITO) is formed after the surface modification as in this embodiment, the heat treatment is not performed in a state where the materials having different thermal expansion coefficients are in direct contact with each other. Therefore, it is possible to prevent the occurrence of ITO cracks and the like, and it is possible to prevent deterioration of the light emitting element. The plasma treatment of the second interlayer insulating film (935, 3926) may be performed before or after the contact hole is formed.
[0115]
The cured film 935B has a surface of the second interlayer insulating film (935, 3926) made of an organic insulating material on the surface of hydrogen, nitrogen, hydrocarbon, halogenated carbon, hydrogen fluoride, or a rare gas (Ar, He, Ne, etc.). And a plasma treatment in one or a plurality of gases selected from. Accordingly, it is considered that the cured film 935B contains a gaseous element such as hydrogen, nitrogen, hydrocarbon, halogenated carbon, hydrogen fluoride, or a rare gas (Ar, He, Ne, etc.).
[0116]
(Example 4)
According to Example 1 or Example 2, the layers up to the second interlayer insulating film (935, 3926) are formed. Next, as shown in FIG. 12, a DLC film 936B may be formed as the first insulating film 936 on the second interlayer insulating film (935, 3926).
[0117]
As a feature of the DLC film, 1550cm^-11300cm with asymmetric peaks around^-1It has a Raman spectral distribution with shoulders around. In addition, when measured with a microhardness meter, it exhibits a hardness of 15 to 25 GPa and has excellent chemical resistance. Furthermore, the DLC film can be formed by a CVD method or a sputtering method, and can be formed in a temperature range from room temperature to 100 ° C. or less. As a film formation method, a method such as a sputtering method, an ECR plasma CVD method, a high frequency plasma CVD method, or an ion beam evaporation method may be used, and the film thickness may be about 5 to 50 nm.
[0118]
(Example 5)
In this embodiment, an example in which an insulating film other than a DLC film is applied as the insulating film 936 over the second interlayer insulating film (935, 3926) will be described.
[0119]
According to Example 1 or Example 2, the layers up to the second interlayer insulating film (935, 3926) are formed. Subsequently, as the first insulating film 936, a silicon nitride film 936 is formed by a sputtering method using silicon as a target. The film forming conditions may be selected as appropriate, but nitrogen (N₂) Or a mixed gas of nitrogen and argon, and high frequency power is applied to perform sputtering. The substrate temperature is set to room temperature, and the heating means may not be used. However, when an organic insulating film is used for the interlayer insulating film, it is desirable to form the film without heating the substrate. In order to sufficiently remove the adsorbed or occluded water, it is preferable to perform dehydration by heating at about 50 to 100 ° C. for several minutes to several hours in a vacuum. As an example of the film formation conditions, a silicon target of 1 to 2 Ω sq. To which boron is added is used, and only nitrogen gas is supplied and a high frequency power (13.56 MHz) of 0.4 Pa and 800 W is used. A film forming speed of 2 to 4 nm / min can be obtained when the diameter is 152.4 mm.
[0120]
The silicon nitride film thus obtained has a concentration of oxygen and hydrogen mentioned as impurity elements in the film of 1 atomic% or less and a transmittance of 80% or more in the visible light region. In particular, it has a transmittance of 80% or more even at a wavelength of 400 nm, indicating the transparency of this film. Furthermore, a dense film can be formed without causing significant damage to the surface.
[0121]
As described above, a silicon nitride film can be used for the insulating film 936. The subsequent steps may be performed again according to Example 1 or Example 2.
[0122]
(Example 6)
In this embodiment, an example in which an insulating film other than a DLC film is applied as the first insulating film 936 over the second interlayer insulating film (935, 3926) will be described.
[0123]
According to Example 1 or Example 2, the layers up to the second interlayer insulating film (935, 3926) are formed. Subsequently, using an aluminum nitride (AlN) target, in an atmosphere in which argon gas and nitrogen gas are mixed, Al_XN_YA film is formed. Al_XN_YImpurities contained in the film, particularly oxygen, may be 0 to less than 10 atm%, and the oxygen concentration can be adjusted by appropriately adjusting sputtering conditions (substrate temperature, source gas and its flow rate, film forming pressure, etc.). . Alternatively, an aluminum (Al) target may be used to form a film in an atmosphere containing nitrogen gas. Note that the present invention is not limited to the sputtering method, and a vapor deposition method or other known techniques may be used.
[0124]
Al_XN_YIn addition to the film, an aluminum nitride (AlN) target is used and AlN is formed in an atmosphere in which argon gas, nitrogen gas, and oxygen gas are mixed._XO_YA membrane may be used. AlN_XO_YThe film may be in a range containing several atom% or more of nitrogen, preferably 2.5 atom% to 47.5 atom%, and the sputtering conditions (substrate temperature, source gas and its flow rate, film formation pressure, etc.) are appropriately adjusted. The nitrogen concentration can be adjusted. Alternatively, an aluminum (Al) target may be used to form a film in an atmosphere containing nitrogen gas and oxygen gas. Note that the present invention is not limited to the sputtering method, and a vapor deposition method or other known techniques may be used.
[0125]
Al mentioned above_XN_YFilm or AlN_XO_YThe film has high light-transmitting properties (transmittance of 80% to 91.3% in the visible light region) and does not hinder light emission from the light-emitting element.
[0126]
As described above, the insulating film 936 has Al._XN_YFilm or AlN_XO_YA membrane can be applied. The subsequent steps may be performed again according to the first embodiment.
[0127]
(Example 7)
According to Example 1 or Example 2, the layers up to the second interlayer insulating film (935, 3926) are formed. Next, as shown in FIG. 13, the surface of the second interlayer insulating film (935, 3926) is subjected to plasma modification to form a cured film 935B, and then a DLC film 936B is formed on the cured film 935B. May be. Note that the DLC film 936B may be formed with a film thickness of about 5 to 50 nm by a sputtering method, an ECR plasma CVD method, a high-frequency plasma CVD method, or an ion beam evaporation method.
[0128]
(Example 8)
An example of performing surface modification of the bank (947, 3938) by performing plasma treatment on the surface of the bank (947, 3938) after forming the bank (947, 3938) in accordance with the steps of Example 1 or Example 2. 8 will be used for explanation.
[0129]
The banks (947, 3938) are formed using an organic resin insulating film. However, the banks (947, 3938) generate moisture and gas, and moisture and gas are easily generated by heat generated when the light emitting device is actually used. There is a problem that it ends up.
[0130]
Therefore, after performing the heat treatment, plasma treatment is performed in order to modify the surface of the bank as shown in FIG. Plasma treatment is performed in one or a plurality of gases selected from hydrogen, nitrogen, carbon halide, hydrogen fluoride, or a rare gas.
[0131]
As a result, the bank surface is densified, and a cured film containing one or more gas elements selected from hydrogen, nitrogen, carbon halide, hydrogen fluoride, or a rare gas is formed, and moisture or gas (oxygen) is formed from the inside. Can be prevented and deterioration of the light emitting element can be prevented.
[0132]
Note that this embodiment can be used in combination with any of Embodiments 1 to 7.
[0133]
Example 9
According to Embodiment 1, the layers up to the second interlayer insulating film (935, 3926) are formed (FIG. 18A). Thereafter, a first insulating film 936 is formed over the second interlayer insulating film (935, 3926). As the first insulating film 936, the DLC film, the silicon nitride film, the aluminum nitride film, or the aluminum nitride oxide film described in Embodiment 2 or 3 may be formed. Subsequently, an ITO film is formed over the first insulating film 936 and patterned into a desired shape to form an anode 1937.
[0134]
Subsequently, a resist mask having a predetermined pattern is formed, and contact holes reaching the impurity regions to be source regions or drain regions formed in the respective semiconductor layers are formed by a dry etching method or the like. This may be according to the first embodiment.
[0135]
Thereafter, a conductive metal film is formed by a sputtering method or a vacuum deposition method, and etched to form wirings 1938 to 1944. The wirings 1938 to 1944 may be formed of a laminated film of a Ti film having a thickness of 50 nm and an alloy film (alloy film of Al and Ti) having a thickness of 500 nm, as in the first embodiment.
[0136]
As shown in this embodiment (FIG. 18B), by forming the anode 1937 in front of the wirings 1938 to 194, even if the anode has to be formed using a material with poor coverage, the wiring breaks. Since 1943 is formed on the anode 1938, a problem such as disconnection does not occur.
[0137]
Once the wiring is formed, a bank, an organic compound layer, and a cathode may be formed according to Example 1.
[0138]
The present embodiment can be applied in combination with the first to seventh embodiments.
[0139]
(Example 10)
In this embodiment, a method for crystallizing a semiconductor film to be an active layer of a TFT using a catalytic element and then reducing the concentration of the catalytic element in the obtained crystalline semiconductor film will be described.
[0140]
In FIG. 17A, the substrate 1100 can preferably be made of barium borosilicate glass, alumino borosilicate glass, quartz, or the like. An inorganic insulating film with a thickness of 10 to 200 nm is formed as a base insulating film 1101 on the surface of the substrate 1100. An example of a suitable base insulating film is a silicon oxynitride film manufactured by a plasma CVD method._Four, NH_Three, N₂A first silicon oxynitride film 1101a made of O is formed to a thickness of 50 nm, and then SiH_FourAnd N₂A film in which a second silicon oxynitride film 1101b manufactured from O is formed to a thickness of 100 nm is applied. The base insulating film 1101 is provided so that alkali metal contained in the glass substrate does not diffuse into the semiconductor film formed thereover, and can be omitted when quartz is used as the substrate.
[0141]
Next, a silicon nitride film 1102 is formed over the base insulating film 1101. The silicon nitride film 1102 further contains oxygen contained in the base insulating film 1101 in order to prevent a catalytic element (typically nickel) used in a subsequent crystallization process of the semiconductor film from getting into the base insulating film 1101. It is formed for the purpose of preventing adverse effects. Note that the silicon nitride film 1102 may be formed with a thickness of 1 to 5 nm by a plasma CVD method.
[0142]
Next, an amorphous semiconductor film 1103 is formed over the silicon nitride film 1102. For the amorphous semiconductor film 1103, a semiconductor material containing silicon as its main component is used. Typically, an amorphous silicon film, an amorphous silicon germanium film, or the like is applied, and the film is formed to a thickness of 10 to 100 nm by a plasma CVD method, a low pressure CVD method, or a sputtering method. In order to obtain high-quality crystals, the concentration of impurities such as oxygen and nitrogen contained in the amorphous semiconductor film 1103 is set to 5 × 10.¹⁸/ Cm^ThreeIt should be reduced to the following. These impurities interfere with the crystallization of the amorphous semiconductor, and also increase the density of trapping centers and recombination centers even after crystallization. Therefore, it is desirable not only to use a high-purity material gas but also to use an ultrahigh vacuum-compatible CVD apparatus equipped with a mirror surface treatment (electropolishing treatment) in the reaction chamber and an oil-free vacuum exhaust system. Note that the base insulating film 1101 to the amorphous semiconductor film 1103 can be continuously formed without being exposed to the atmosphere.
[0143]
Thereafter, a metal element having a catalytic action for promoting crystallization is added to the surface of the amorphous silicon film 1103 (FIG. 17B). Metal elements having a catalytic action for promoting crystallization of semiconductor films include iron (Fe), nickel (Ni), cobalt (Co), ruthenium (Ru), rhodium (Rh), palladium (Pd), and osmium (Os). , Iridium (Ir), platinum (Pt), copper (Cu), gold (Au), etc., and one or more selected from these can be used. Typically, nickel is used, and a catalyst-containing layer 1104 is formed by applying a nickel acetate salt solution containing 1 to 100 ppm of nickel by weight with a spinner. In this case, in order to improve the familiarity of the solution, as the surface treatment of the amorphous silicon film 1103, an extremely thin oxide film is formed with an ozone-containing aqueous solution, and the oxide film is mixed with hydrofluoric acid and hydrogen peroxide solution. After etching to form a clean surface, an ultrathin oxide film is formed again by treatment with an ozone-containing aqueous solution. Since the surface of the semiconductor film such as silicon is inherently hydrophobic, the nickel acetate salt solution can be uniformly applied by forming the oxide film in this way.
[0144]
Needless to say, the catalyst-containing layer 1104 is not limited to such a method, and may be formed by sputtering, vapor deposition, plasma treatment, or the like.
[0145]
Heat treatment for crystallization is performed while keeping the amorphous silicon film 1103 and the catalytic element-containing layer 1104 in contact with each other. Heat treatment methods include furnace annealing using an electric furnace, and rapid thermal annealing using halogen lamps, metal halide lamps, xenon arc lamps, carbon arc lamps, high pressure sodium lamps, high pressure mercury lamps, etc. (Hereinafter referred to as RTA method).
[0146]
When the RTA method is used, the lamp light source for heating is turned on for 1 to 60 seconds, preferably 30 to 60 seconds, and this is repeated 1 to 10 times, preferably 2 to 6 times. The emission intensity of the lamp light source is arbitrary, but the semiconductor film is instantaneously heated to 600 to 1000 ° C., preferably about 650 to 750 ° C. Even at such a high temperature, the semiconductor film is only heated instantaneously, and the substrate 1100 itself is not distorted and deformed. In this way, the amorphous semiconductor film can be crystallized to obtain the crystalline silicon film 1105 shown in FIG. 17 (c). The crystal can be crystallized by such treatment only by providing the catalyst element-containing layer. It can be achieved.
[0147]
In the case where the furnace annealing method is used as another method, the heat treatment is performed at 500 ° C. for about one hour prior to the heat treatment to release hydrogen contained in the amorphous silicon film 1103. Then, the amorphous silicon film 1103 is crystallized by performing heat treatment at 550 to 600 ° C., preferably 580 ° C. for 4 hours in a nitrogen atmosphere using an electric furnace. Thus, a crystalline silicon film 1105 shown in FIG. 17C is formed.
[0148]
It is also effective to irradiate the crystalline silicon film 1105 with laser light in order to further increase the crystallization rate (the ratio of the crystal component in the total volume of the film) and repair defects remaining in the crystal grains. .
[0149]
The crystalline silicon film 1105 obtained in this way has an average concentration of the catalyst element (here, nickel) of 1 × 10 5.¹⁹/ Cm^ThreeRemaining at a concentration exceeding If the catalyst element remains, the TFT characteristics may be adversely affected, so the concentration of the catalyst element in the semiconductor layer needs to be reduced. Therefore, a method for reducing the catalyst element concentration of the semiconductor layer following the crystallization step will be described.
[0150]
First, as shown in FIG. 17D, a thin layer 1106 is formed on the surface of the crystalline silicon film 1105. In this specification, the thin layer 1106 provided over the crystalline silicon film 1105 is a layer provided so that the crystalline silicon film 1105 is not etched when the gettering site is removed later, and is referred to as a barrier layer 1106. To do.
[0151]
The thickness of the barrier layer 1106 is about 1 to 10 nm, and chemical oxide formed by treatment with ozone water may be used as the barrier layer. Similarly, chemical oxide can be formed by treatment with an aqueous solution in which sulfuric acid, hydrochloric acid, nitric acid or the like and hydrogen peroxide are mixed. As another method, the oxidation treatment may be performed by generating ozone by plasma treatment in an oxidizing atmosphere or ultraviolet irradiation in an oxygen-containing atmosphere. Alternatively, a thin oxide film may be formed by heating to about 200 to 350 ° C. using a clean oven to form a barrier layer. Alternatively, a barrier layer may be formed by depositing an oxide film of about 1 to 5 nm by plasma CVD, sputtering, vapor deposition, or the like. In any case, the catalyst element can move to the gettering site during the gettering step, and the etchant does not permeate during the gettering site removal step (the crystalline silicon film 1105 is protected from the etchant). For example, a chemical oxide film, a silicon oxide film (SiOx), or a porous film formed by treatment with ozone water may be used.
[0152]
Next, a gettering site 1107 is formed on the barrier layer 1106 by a sputtering method so that a rare gas element is 1 × 10 6 in the film.²⁰/ Cm^ThreeA second semiconductor film (typically an amorphous silicon film) including the above concentration is formed with a thickness of 25 to 250 nm. A gettering site 1107 to be removed later is preferably formed as a low-density film in order to increase the etching selectivity between the crystalline silicon film 1105 and the etching.
[0153]
Note that the rare gas element itself is inactive in the semiconductor film and thus does not adversely affect the crystalline silicon film 1105. As the rare gas element, one or more selected from helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe) are used. The present invention is characterized in that these rare gas elements are used as an ion source in order to form a gettering site, and that a semiconductor film containing these elements is formed and this film is used as a gettering site.
[0154]
In order to achieve the gettering reliably, it is necessary to perform heat treatment thereafter. The heat treatment is performed by a furnace annealing method or an RTA method. In the case of performing furnace annealing, heat treatment is performed at 450 to 600 ° C. for 0.5 to 12 hours in a nitrogen atmosphere. When the RTA method is used, the lamp light source for heating is turned on for 1 to 60 seconds, preferably 30 to 60 seconds, and this is repeated 1 to 10 times, preferably 2 to 6 times. The emission intensity of the lamp light source is arbitrary, but the semiconductor film is instantaneously heated to 600 to 1000 ° C., preferably about 700 to 750 ° C.
[0155]
In the gettering, the catalytic element in the gettering region (capture site) is released by thermal energy and moves to the gettering site by diffusion. Accordingly, the gettering depends on the processing temperature, and the gettering proceeds in a shorter time as the temperature is higher. In the present invention, the distance that the catalytic element travels during gettering is about the thickness of the semiconductor film, and the gettering can be completed in a relatively short time (FIG. 17E).
[0156]
In addition, 1 * 10 also by this heat processing.¹⁹/ Cm^Three~ 1x10^{twenty one}/ Cm^Three, Preferably 1 × 10²⁰/ Cm^Three~ 1x10^{twenty one}/cm^Three, More preferably 5 × 10²⁰/ Cm^ThreeThe semiconductor film 1107 containing a rare gas element at a concentration of 1 is not crystallized. This is presumably because the rare gas element remains in the film without being re-emitted even in the above processing temperature range and inhibits crystallization of the semiconductor film.
[0157]
After the gettering step is completed, the gettering site 1107 is selectively etched and removed. As an etching method, ClF_ThreeDry etching without plasma by hydrazine, tetraethylammonium hydroxide (chemical formula (CH_Three)_FourNOH) can be performed by wet etching with an alkaline solution such as an aqueous solution. At this time, the barrier layer 1106 functions as an etching stopper. Further, the barrier layer 1106 may be removed thereafter with hydrofluoric acid.
[0158]
Thus, as shown in FIG. 17 (f), the concentration of the catalytic element is 1 × 10.¹⁷/ Cm^ThreeA crystalline silicon film 1108 reduced to the following can be obtained. The crystalline silicon film 1108 thus formed is formed as a thin rod-like or thin flat rod-like crystal by the action of the catalytic element, and each crystal grows in a specific direction as viewed macroscopically.
[0159]
This embodiment can be used in combination with Embodiments 1-9.
[0160]
(Example 11)
In this example, a method for completing a light-emitting panel manufactured to the state illustrated in FIG. 6B by combining the manufacturing steps of Examples 1 to 10 as a light-emitting device will be described in detail with reference to FIGS.
[0161]
9A is a top view of a light-emitting panel in which an element substrate is sealed, and FIG. 9B is a cross-sectional view taken along line A-A ′ of FIG. 9A. 801 indicated by a dotted line is a source side driver circuit, 802 is a pixel portion, and 803 is a gate side driver circuit. Reference numeral 804 denotes a sealing substrate, 805 denotes a sealing agent, and a space 807 is surrounded by the sealing agent 805.
[0162]
Note that a video signal or a clock signal is received from an FPC (flexible printed circuit) 809 serving as an external input terminal by wiring (not shown) for transmitting a signal input to the source side driver circuit 801 and the gate side driver circuit 803. receive. Note that although a state in which an FPC is connected to the light-emitting panel is shown here, a module in which an IC (integrated circuit) is directly mounted via the FPC is referred to as a light-emitting device in this specification.
[0163]
Next, a cross-sectional structure is described with reference to FIG. Over the substrate 810, a pixel portion 802 and a driver circuit portion are formed. The pixel portion 802 is formed by a plurality of pixels including a current control TFT 811 and an anode 812 electrically connected to a drain thereof. The driver circuit portion is formed using a CMOS circuit in which an n-channel TFT 813 and a p-channel TFT 814 are combined.
[0164]
In addition, after the banks 815 are formed on both ends of the anode 812, the insulating film 821, the organic compound layer 816, and the cathode 817 are formed over the anode 812, so that the light emitting element 818 is formed.
[0165]
Note that the cathode 817 functions as a wiring common to all pixels, and is electrically connected to the FPC 809 via a connection wiring 808.
[0166]
Note that a sealing substrate 804 made of glass is attached to a sealing agent 805. Note that an ultraviolet curable resin or a thermosetting resin is preferably used as the sealant 805. In addition, a spacer made of a resin film may be provided as necessary in order to secure a space between the sealing substrate 804 and the light emitting element 818. A space 807 inside the sealant 805 is filled with an inert gas such as nitrogen or a rare gas. Further, the sealant 805 is desirably a material that does not transmit moisture and oxygen as much as possible.
[0167]
By enclosing the light-emitting element in the space 807 with the above structure, the light-emitting element can be completely blocked from the outside, and deterioration of the light-emitting element due to moisture or oxygen entering from the outside can be prevented. Therefore, a highly reliable light-emitting device can be obtained.
[0168]
In addition, the structure in a present Example can be implemented combining the structure of Example 1- Example 10. FIG.
[0169]
Example 12
Here, FIG. 10A shows a more detailed top surface structure of a pixel portion of a light emitting device formed using the present invention, and FIG. 10B shows a circuit diagram thereof. In FIG. 10, a switching TFT 704 provided on a substrate is formed using the switching (n-channel) TFT 1002 in FIG. Therefore, the description of the structure may be referred to the description of the switching (n-channel type) TFT 1002. A wiring denoted by 703 is a gate wiring that electrically connects the gate electrodes 704a and 704b of the switching TFT 704.
[0170]
Note that although a double gate structure in which two channel formation regions are formed is used in this embodiment, a single gate structure in which one channel formation region is formed or a triple gate structure in which three channel formation regions are formed may be used.
[0171]
The source of the switching TFT 704 is connected to the source wiring 715, and the drain is connected to the drain wiring 705. The drain wiring 705 is electrically connected to the gate electrode 707 of the current control TFT 706. Note that the current control TFT 706 is formed using the current control (p-channel) TFT 1003 in FIG. Therefore, the description of the structure may be referred to the description of the current control (p-channel type) TFT 1003. In this embodiment, a single gate structure is used, but a double gate structure or a triple gate structure may be used.
[0172]
The source of the current control TFT 706 is electrically connected to the current supply line 716, and the drain is electrically connected to the drain wiring 717. The drain wiring 717 is electrically connected to an anode (pixel electrode) 718 indicated by a dotted line.
[0173]
At this time, a storage capacitor (capacitor) is formed in a region indicated by 719. The capacitor 719 is formed between the semiconductor layer 720 electrically connected to the current supply line 716, an insulating film (not shown) that is the same layer as the gate insulating film, and the gate electrode 707. A capacitor formed by the gate electrode 707, the same layer (not shown) as the first interlayer insulating film, and the current supply line 716 can also be used as the storage capacitor.
[0174]
In addition, the structure of a present Example can be implemented combining the structure of Example 1- Example 10. FIG.
[0175]
(Example 13)
Another example of the process for manufacturing the light-emitting device, which is different from that in Example 2, will be described with reference to FIGS.
[0176]
First, the process proceeds to the state of FIG. Thereafter, the TFT substrate is carried into the second processing chamber, and the antistatic film is removed by washing with water. Then, as shown in FIG. 23A, a bank 3938 is formed. The surface of the bank 3938 may be covered with an insulating film such as a silicon nitride film as in the second embodiment, or the surface may be modified by performing a plasma treatment as in the eighth embodiment.
[0177]
On the anode 3928, a first organic compound layer 3950 formed of a polymer organic compound is first formed by using a spin coating method, a spray method, or the like. This layer is formed of a polymer organic compound material having a hole injecting and transporting property or a polymer organic compound material having a high hole mobility. Polyethylene dioxythiophene (PEDOT) can be applied as the polymer organic compound material.
[0178]
The second organic compound layer 3951 and the cathode 3952 such as a light emitting layer and an electron transport layer formed thereon may be formed in the same manner as in Example 1.
[0179]
As shown in detail in FIG. 23B, the thickness of the first organic compound layer 3950 can be adjusted by adjusting the viscosity as appropriate to the film thickness (t1) on the anode 3928 and the film thickness (t2) on the bank 3938. And can be different. That is, the thickness (t1) on the anode 3928 can be increased by the recess formed on the anode 3928 by the bank 3938.
[0180]
Further, the thickness (t3) of the end portion 3958 where the anode 3928 and the bank 3938 are in contact with each other is the largest, and can be formed with a curvature. With such a shape, the coverage of the second organic compound layer 3951 and the cathode 3952 formed thereon can be improved. Further, cracks and electric field concentration due to stress concentration are suppressed, and defects due to deterioration or short-circuiting of the light emitting element can be prevented.
[0181]
(Example 14)
Since a light-emitting device using a light-emitting element is a self-luminous type, it is superior in visibility in a bright place and has a wide viewing angle as compared with a liquid crystal display device. Therefore, it can be used for display portions of various electric appliances.
[0182]
As an electric appliance using a light emitting device manufactured according to the present invention, a video camera, a digital camera, a goggle type display (head mounted display), a navigation system, a sound reproduction device (car audio, audio component, etc.), a notebook personal computer, a game A device, a portable information terminal (mobile computer, mobile phone, portable game machine, electronic book, or the like), and an image playback device provided with a recording medium (specifically, a recording medium such as a DVD can be played back and the image displayed) And a device provided with a display device). In particular, a portable information terminal that frequently sees a screen from an oblique direction emphasizes the wide viewing angle, and thus a light emitting device having a light emitting element is preferably used. Specific examples of these electric appliances are shown in FIG.
[0183]
FIG. 11A illustrates a display device, which includes a housing 2001, a support base 2002, a display portion 2003, a speaker portion 2004, a video input terminal 2005, and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2003. Since a light-emitting device having a light-emitting element is a self-luminous type, a backlight is not necessary and a display portion thinner than a liquid crystal display device can be obtained. The display devices include all information display devices for personal computers, for receiving TV broadcasts, for displaying advertisements, and the like.
[0184]
FIG. 11B shows a digital still camera, which includes a main body 2101, a display portion 2102, an image receiving portion 2103, operation keys 2104, an external connection port 2105, a shutter 2106, and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2102.
[0185]
FIG. 11C illustrates a laptop personal computer, which includes a main body 2201, a housing 2202, a display portion 2203, a keyboard 2204, an external connection port 2205, a pointing mouse 2206, and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2203.
[0186]
FIG. 11D illustrates a mobile computer, which includes a main body 2301, a display portion 2302, a switch 2303, operation keys 2304, an infrared port 2305, and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2302.
[0187]
FIG. 11E illustrates a portable image reproducing device (specifically, a DVD reproducing device) provided with a recording medium, which includes a main body 2401, a housing 2402, a display portion A2403, a display portion B2404, and a recording medium (DVD or the like). A reading unit 2405, operation keys 2406, a speaker unit 2407, and the like are included. Although the display portion A 2403 mainly displays image information and the display portion B 2404 mainly displays character information, the light-emitting device manufactured according to the present invention can be used for the display portions A 2403 and B 2404. Note that an image reproducing device provided with a recording medium includes a home game machine and the like.
[0188]
FIG. 11F illustrates a goggle type display (head mounted display), which includes a main body 2501, a display portion 2502, and an arm portion 2503. The light emitting device manufactured according to the present invention can be used for the display portion 2502.
[0189]
FIG. 11G shows a video camera, which includes a main body 2601, a display portion 2602, a housing 2603, an external connection port 2604, a remote control receiving portion 2605, an image receiving portion 2606, a battery 2607, an audio input portion 2608, operation keys 2609, and the like. . The light-emitting device manufactured according to the present invention can be used for the display portion 2602.
[0190]
Here, FIG. 11H illustrates a mobile phone, which includes a main body 2701, a housing 2702, a display portion 2703, an audio input portion 2704, an audio output portion 2705, operation keys 2706, an external connection port 2707, an antenna 2708, and the like. The light-emitting device manufactured according to the present invention can be used for the display portion 2703. Note that the display portion 2703 can reduce power consumption of the mobile phone by displaying white characters on a black background.
[0191]
If the emission luminance of the organic material is increased in the future, the light including the output image information can be enlarged and projected by a lens or the like and used for a front type or rear type projector.
[0192]
In addition, the electrical appliances often display information distributed through electronic communication lines such as the Internet and CATV (cable television), and in particular, opportunities to display moving image information are increasing. Since the response speed of the organic material is very high, the light-emitting device is preferable for displaying moving images.
[0193]
In addition, since the light emitting portion of the light emitting device consumes power, it is preferable to display information so that the light emitting portion is minimized. Therefore, when a light emitting device is used for a display unit mainly including character information, such as a portable information terminal, particularly a mobile phone or a sound reproduction device, it is driven so that character information is formed by the light emitting part with the non-light emitting part as the background. It is preferable to do.
[0194]
As described above, the applicable range of the light-emitting device manufactured using the present invention is so wide that the light-emitting device can be used for electric appliances in various fields. Moreover, the electric appliance of a present Example can use the light-emitting device produced combining Example 1- Example 12 for the display part.
[0195]
【The invention's effect】
By using the present invention, generation of cracks in the anode can be reduced, so that deterioration of the light emitting element can be suppressed. Further, since the current density in the organic compound layer can be increased by planarizing the surface of the anode, the driving voltage can be reduced and the lifetime of the light emitting element can be extended.
[0196]
In addition, when the processing chamber for manufacturing the TFT substrate and the processing chamber for manufacturing the light-emitting element are physically separated from each other and the substrate must be moved, the TFT substrate may deteriorate the characteristics of the TFT, It can move without being destroyed, and if the structure of the present invention is applied, the TFT is contaminated with an alkali metal as a material of the light emitting element, and the light emitting element is deteriorated by moisture or gas. Can be prevented, and a favorable light-emitting device can be realized.
[Brief description of the drawings]
1A and 1B illustrate an embodiment of a method for manufacturing a light-emitting device.
FIG. 2 illustrates an example of a conventional light emitting device.
3A and 3B illustrate a manufacturing process of a light-emitting device.
4A and 4B illustrate a manufacturing process of a light-emitting device.
FIG. 5 illustrates a manufacturing process of a light-emitting device.
6A and 6B illustrate a manufacturing process of a light-emitting device.
FIG. 7 illustrates an example of a manufacturing process of a light-emitting device.
FIG. 8 illustrates an example of a manufacturing process of a light-emitting device.
FIG 9 illustrates a sealing structure of a light-emitting device.
FIG. 10 illustrates a structure of a pixel portion of a light emitting device.
FIG. 11 illustrates an example of an electric appliance.
FIG. 12 illustrates an example of a manufacturing process of a light-emitting device.
FIG. 13 illustrates an example of a manufacturing process of a light-emitting device.
FIG. 14 is a diagram showing measurement results by AFM.
FIG. 15 is a diagram showing measurement results by AFM.
FIG. 16 is a diagram showing measurement results by AFM.
FIG. 17 illustrates an example of a manufacturing process of a light-emitting device.
FIG. 18 illustrates a manufacturing process of a light-emitting device.
FIG. 19 is a diagram showing an image of a production process according to the present invention.
FIG. 20 illustrates an example of a manufacturing process of a light-emitting device.
FIG. 21 illustrates an example of a manufacturing process of a light-emitting device.
FIG. 22 illustrates an example of a manufacturing process of a light-emitting device.
FIG. 23 illustrates an example of a manufacturing process of a light-emitting device.
[Explanation of symbols]
100 substrates
101 Current control TFT
102 Interlayer insulation film
104 Wiring
106 Anode
107 banks
111 Organic compound layer
112 cathode

Claims (11)

The anode,
A bank made of an organic resin material covering an end of the anode;
An organic compound layer provided on the anode and on a side surface of the bank and an upper surface continuous with the side surface of the bank;
A cathode on the organic compound layer,
The light emitting device according to claim 1, wherein a thickness of the organic compound layer on the anode is larger than a thickness of the organic compound layer on the bank. And T FT,
A first insulating film made of an organic resin material on the TFT;
A second insulating film including a silicon oxide film, a silicon oxynitride film, or a silicon nitride film on the first insulating film;
And an anode on the second insulating film,
A bank made of an organic resin material covering an end of the anode;
An organic compound layer provided on the anode and on a side surface of the bank and an upper surface continuous with the side surface of the bank;
A cathode on the organic compound layer,
The light emitting device according to claim 1, wherein a thickness of the organic compound layer on the anode is larger than a thickness of the organic compound layer on the bank . And T FT,
A first insulating film made of an organic resin material whose surface is modified by hydrogen plasma treatment on the TFT;
A second insulating film made of a DLC film on the first insulating film,
An anode on the second insulating film;
A bank made of an organic resin material covering an end of the anode;
An organic compound layer provided on the anode and on a side surface of the bank and an upper surface continuous with the side surface of the bank;
A cathode on the organic compound layer,
The light emitting device according to claim 1, wherein a thickness of the organic compound layer on the anode is larger than a thickness of the organic compound layer on the bank . TFT,
A first insulating film made of an organic resin material on the TFT;
A second insulating film including an aluminum oxynitride film on the first insulating film;
An anode on the second insulating film;
A bank made of an organic resin material covering an end on the anode;
An organic compound layer provided on the anode and on a side surface of the bank and an upper surface continuous with the side surface of the bank;
A cathode on the organic compound layer,
The light emitting device according to claim 1, wherein a thickness of the organic compound layer on the anode is larger than a thickness of the organic compound layer on the bank. In any one of claims 1 to 4, wherein the anode is light-emitting device which is a transparent conductive film 2% to 20% of zinc oxide to indium oxide is mixed. 6. The film thickness of the organic compound layer on the end of the bank in contact with the anode is the thickness of the organic compound layer on the bank except on the anode and the end. A light emitting device characterized by being thicker than a film thickness. 7. The light emitting device according to claim 1, wherein the organic compound layer is formed by a spin coating method or a spray method. Digital camera, characterized in that the light-emitting device according to any one of claims 1 to 7. Mobile phone, characterized in that the light-emitting device according to any one of claims 1 to 7. Mobile computer, characterized in that the light-emitting device according to any one of claims 1 to 7. A video camera, a goggle-type display, a navigation system, a sound reproduction device, a personal computer, a game device, a portable game machine, an electronic book, wherein the light-emitting device according to any one of claims 1 to 7 is used. Or an image playback device.

Images