JP4649860B2 - Electro-optical device, method of manufacturing electro-optical device, and electronic apparatus - Google Patents

Description

The present invention relates to an electro-optical device , a method for manufacturing the electro-optical device, and an electronic apparatus.

2. Description of the Related Art As an organic electroluminescence device (hereinafter also referred to as an organic EL device) that is one form of an electro-optical device, a configuration in which an organic light emitting layer is disposed between a cathode and an anode is known. In the organic EL element having the above structure, holes injected into the light emitting layer directly from the anode or through the hole injection layer and electrons injected into the light emitting layer directly from the cathode or through the electron injection layer are generated. Recombination produces luminescence.
As means for improving the light emission characteristics of the organic EL element based on such a light emission mechanism, improvement of organic light emitting material and injection material (hole injection material, electron injection material), selection and improvement of cathode material, etc. are known. It has been. For example, Patent Document 1 discloses the use of an alloy of Al and Li for the cathode, and Patent Document 2 discloses the use of an alloy of Ca and Li for the cathode.
Japanese Patent Laid-Open No. 5-121172 Japanese Patent Laid-Open No. 9-232079

  When using a cathode made of a binary material described in each of the above-mentioned documents, a so-called co-evaporation method is used in which materials are vaporized simultaneously from two evaporation sources and evaporated onto a substrate. However, the film forming method using co-evaporation has a problem that the composition of the thin film to be formed cannot be controlled with high accuracy.

  The present invention has been made in view of the above-mentioned problems of the prior art, and the composition of the cathode containing a plurality of constituent elements is highly controlled, so that high-efficiency charge transportability can be obtained, and it can be easily manufactured. An object is to provide a possible electro-optical device. It is another object of the present invention to provide a method for manufacturing the above electro-optical device easily and with high reproducibility.

In order to solve the above problems, the present invention provides an electro-optical device in which an electro-optical layer is sandwiched between an anode and a cathode, wherein the cathode includes a first metal layer containing a low work function metal, There is provided an electro-optical device comprising a laminated metal film in which second metal layers containing a high work function metal having a higher work function than the low work function metal are alternately laminated.
According to the electro-optical device having such a configuration, since the cathode includes a stacked metal film in which the first metal layer and the second metal layer are alternately stacked, the electro-optical layer made of a low work function metal. It is possible to obtain a cathode having both good electron injecting property and good conductivity by a high work function metal. As a result, it is possible to obtain an electro-optical device in which electrons are efficiently supplied to the electro-optical layer, the display is bright, and the power consumption is low. In addition, since the first metal layer and the second metal layer are stacked, unlike the case of forming a two-element cathode by co-evaporation, it can be easily reduced only by changing the layer thickness of each layer. The composition ratio between the work function metal and the high work function metal can be adjusted, and the controllability and reproducibility of the composition ratio are excellent.
Furthermore, in the laminated metal film having the above structure, the composition ratio can be varied depending on the position in the film thickness direction by appropriately changing the film thickness of the first metal layer and the second metal layer in the film thickness direction. Therefore, for example, the composition of the laminated metal film can be changed in accordance with the characteristics of the electro-optical layer, and an electro-optical device with optimized characteristics can be easily obtained.

  In the electro-optical device according to the aspect of the invention, it is preferable that a layer disposed in a position adjacent to the electro-optical layer among the constituent layers of the laminated metal film is the first metal layer. With such a configuration, since the first metal layer made of a low work function metal is disposed adjacent to the electro-optic layer, the electron injectability from the cathode to the electro-optic layer can be enhanced.

  In the electro-optical device according to the aspect of the invention, it is preferable that a layer disposed on a surface layer opposite to the electro-optical layer among the constituent layers of the laminated metal film is the second metal layer. With such a configuration, since the second metal layer containing a high work function metal having excellent conductivity is disposed at the connection portion with the wiring or the like for supplying current to the cathode, electrons from the wiring or the like to the cathode are arranged. Transportability can be improved.

  In the electro-optical device according to the aspect of the invention, the laminated metal film may have a structure in which the first metal layer having a certain thickness and the second metal layer having a certain thickness are alternately laminated. Can do. According to this configuration, it is possible to easily and efficiently manufacture a laminated metal film having desired characteristics, and thus it is possible to provide an electro-optical device that can be manufactured efficiently.

  In the electro-optical device according to the aspect of the invention, the ratio (d1 / d2) between the thickness d1 of the first metal layer and the thickness d2 of the second metal layer adjacent to each other at a plurality of portions in the thickness direction of the laminated metal film. ) May be different. According to this configuration, since the composition ratio of the low work function metal and the high work function metal can be arbitrarily changed in the film thickness direction of the multilayer metal film, the layer metal film and the adjacent layer (electro-optic layer, etc.) It is possible to optimize the state in the vicinity of the interface and easily cope with a change in the type of the electro-optic layer.

  In the electro-optical device according to the aspect of the invention, the film thickness ratio (d1 / d2) is relatively small on the electro-optic layer side and relatively on the opposite side to the electro-optic layer in the film thickness direction of the laminated metal film. It is preferable to make the structure larger. According to this configuration, the electro-optic layer connected to a wiring or the like can be obtained by increasing the content of the low work function metal in the portion adjacent to the electro-optic layer to obtain a good electron injection property to the electro-optic layer. Good conductivity and stability due to the high work function metal can be obtained at the opposite site. Therefore, it is possible to obtain a cathode excellent in electron injection / transport properties to the electro-optical layer and excellent in film stability.

In the electro-optical device according to the aspect of the invention, it is preferable that the first metal layer and the second metal layer have a thickness of 10 nm or less. More preferably, the layer thickness is 5 nm or less, and more desirably 1 nm or less. The layer thickness in this case is a calculated layer thickness based on the deposition rate of each evaporation source, and the first metal layer and the second metal layer that are actually formed have the layer thickness in the laminated film. It is not necessary to have a simple layer structure.
The lower limit of the layer thickness is reduced to the minimum thickness that enables uniform deposition with good reproducibility in a film forming apparatus such as a vapor deposition apparatus used for forming the first metal layer and the second metal layer. Can do. Therefore, if possible, the thickness of each layer may be less than 0.1 nm.

  In the electro-optical device according to the aspect of the invention, the high-work function metal is included on the opposite side of the multilayer metal film to the electro-optical layer, and the film thickness is larger than the first metal layer and the second metal layer constituting the multilayer film. It is also possible to employ a configuration in which an electrode film having According to this configuration, the electrode film containing a high work function metal having excellent conductivity and film quality stability can improve the electron supply property to the multilayer metal film, and the multilayer metal film (particularly, It is possible to satisfactorily protect the low work function metal contained therein.

In the electro-optical device according to the aspect of the invention, it is preferable that the low work function metal is at least one metal selected from the group consisting of magnesium, an alkali metal, an alkaline earth metal, and a rare earth metal.
In the electro-optical device according to the aspect of the invention, it is preferable that the high work function metal material is one or more metals selected from the group consisting of conductive transition metals.

  In the electro-optical device according to the aspect of the invention, the electro-optical layer may include an organic light emitting layer. According to this configuration, it is possible to provide an organic electroluminescence device that can efficiently inject electrons into the organic light-emitting layer, thereby enabling high-luminance display and low power consumption.

Next, a method for manufacturing an electro-optical device according to the present invention is a method for manufacturing an electro-optical device in which an electro-optical layer is sandwiched between an anode and a cathode, and the step of forming the cathode has a low work function. A step of forming a laminated metal film by alternately laminating a first metal layer containing a metal material and a second metal layer containing a metal material having a higher work function than the metal material having a low work function. It is characterized by being.
Thus, by adopting a manufacturing method in which the step of forming a laminated metal film is included in the cathode forming step, it is possible to easily change the thickness of each of the first metal layer and the second metal layer as appropriate to obtain the laminated metal. It is possible to adjust the composition ratio between the low work function metal and the high work function metal in the film. Therefore, it is possible to control the composition ratio with high accuracy that cannot be obtained by the conventional method of forming a two-element cathode by co-evaporation. In the case of co-evaporation, when the state of the evaporation source changes with time, the composition ratio of the cathode to be formed becomes a problem. However, in this manufacturing method, a plurality of metal layers are alternately formed. Therefore, even if the film formation speed changes with time, it can be easily corrected, and it is a manufacturing method suitable for mass production that can withstand long-time film formation processing.

In the method of manufacturing the electro-optical device according to the aspect of the invention, when the multilayer metal film is formed, a plurality of thickness ratios between the first metal layer and the second metal layer adjacent to the first metal layer are changed. The first metal layer and the second metal layer may be laminated.
According to this manufacturing method, the composition ratio between the low work function metal and the high work function metal can be easily adjusted in the film thickness direction of the laminated metal film. Optimization can be performed easily.

In the method of manufacturing the electro-optical device according to the aspect of the invention, when the stacked metal film is formed, the film thickness d1 of the first metal layer and the film thickness d2 of the second metal layer adjacent to the first metal layer are determined. The first metal layer and the first metal layer have a ratio (d1 / d2) that is relatively large on the electro-optic layer side in the film thickness direction of the multilayer metal film and relatively small on the opposite side to the electro-optic layer. Two metal layers can also be laminated.
According to this manufacturing method, on the electro-optic layer side in the film thickness direction of the laminated metal film, the content of the low work function metal can be increased to obtain good electron injection properties, and the wiring on the opposite side of the electro-optic layer, etc. In the portion forming the connecting portion, the high work function metal content can be increased to obtain good conductivity and film quality stability. Therefore, according to this manufacturing method, it is possible to manufacture an electro-optical device that includes a cathode capable of supplying electrons to the electro-optical layer with high efficiency, and thereby provides a bright display.

Next, a vapor deposition apparatus of the present invention is a vapor deposition apparatus comprising a plurality of vapor deposition sources that emit vapor deposition species to be deposited on a substrate, and opens and closes the vapor deposition species emitted from the plurality of vapor deposition sources. Shielding means that can be shielded by operation, and film formation in which a plurality of kinds of vapor deposition species are sequentially deposited on the substrate by controlling the opening / closing operation of the shielding means so that only the predetermined vapor deposition species are deposited on the substrate. And a control means.
According to this configuration, it is possible to provide a vapor deposition apparatus capable of selectively depositing only a specific vapor deposition species on the substrate by the film formation control unit. Therefore, the electro-optic according to the present invention described above A vapor deposition apparatus suitable for use in the manufacturing method of the apparatus is provided.

  In the vapor deposition apparatus of the present invention, a plurality of the shielding means are provided corresponding to each of the plurality of vapor deposition sources, and the film formation control means sequentially opens and closes the plurality of shielding means on the substrate. It can also be set as the structure which deposits a multiple types of vapor deposition seed | species sequentially.

  In the vapor deposition apparatus of the present invention, the shielding means is provided with a shielding plate disposed to face the plurality of vapor deposition sources, and a rotation driving unit that rotates the shielding plate within a plate surface, and the shielding The plate surface of the plate is provided with an opening for allowing only the predetermined vapor deposition species to pass therethrough, and the position of the opening is sequentially moved by the rotation of the shielding plate, and a predetermined value is passed through the opening. A film forming control unit that drives and controls the rotation driving unit so as to sequentially deposit vapor deposition species on the substrate may be provided.

The vapor deposition apparatus of the present invention is a vapor deposition apparatus in which a plurality of vapor deposition sources for releasing vapor deposition species to be deposited on a substrate are arranged in a film formation container, wherein the plurality of vapor deposition sources are disposed in the film formation container. Each substrate is disposed in a plurality of vapor deposition chambers, and a substrate transport means is provided for moving the substrate between the plurality of vapor deposition chambers.
A film forming control unit is provided for driving the substrate transport means to move the substrate between the plurality of vapor deposition chambers to sequentially deposit predetermined vapor deposition species on the substrate.
According to this configuration, it is possible to select the vapor deposition species to be deposited on the substrate by moving the substrate, and thus it is possible to repeat the operation of depositing only a specific vapor deposition species on the substrate, and a predetermined laminated structure is provided. An evaporation apparatus capable of forming a laminated metal film is provided.

  Next, an electronic apparatus according to the invention includes the electro-optical device according to the invention described above. According to this configuration, an electronic device including a display unit with high luminous efficiency or low power consumption is provided.

(EL display device)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, as an embodiment of an electro-optical device according to the present invention, an EL display device using an electroluminescent material, particularly an organic electroluminescence (EL) material, which is an example of an electro-optical material will be described.

FIG. 1 is a diagram showing a wiring structure of the EL display device 1. The EL display device 1 is an active matrix EL display device using a thin film transistor (hereinafter abbreviated as TFT) as a switching element.
As shown in FIG. 1, the EL display device (electro-optical device) 1 includes a plurality of scanning lines 101, a plurality of signal lines 102 extending in a direction perpendicular to each scanning line 101, and each signal line 102. And a plurality of power supply lines 103 extending in parallel with each other.

  A pixel region X is provided near each intersection of the scanning line 101 and the signal line 102. A scanning line driving circuit 80 including a shift register and a level shifter is connected to the scanning line 101. A data line driving circuit 100 including a shift register, a level shifter, a video line, and an analog switch is connected to the signal line 102.

  In each of the pixel regions X, a switching TFT 112 that receives supply of a scanning signal to the gate electrode via the scanning line 101 and a storage capacitor that holds a pixel signal supplied from the signal line 102 via the switching TFT 112. 113 and a driving TFT 123 to which a pixel signal held by the holding capacitor 113 is supplied to the gate electrode are provided. In addition, when electrically connected to the power supply line 103 via the driving TFT 123, the pixel electrode (electrode) 23 into which a drive current flows from the power supply line 103, and between the pixel electrode 23 and the cathode (electrode) 50. A functional layer 110 sandwiched is provided. In the EL display device, the pixel electrode 23, the cathode 50, and the functional layer 110 constitute a light emitting element (organic EL element).

  In the EL display device 1, when the scanning line 101 is driven and the switching TFT 112 is turned on, the potential of the signal line 102 at that time is held in the holding capacitor 113, and according to the state of the holding capacitor 113. Then, the on / off state of the driving TFT 123 is determined. Then, current flows from the power supply line 103 to the pixel electrode 23 through the channel of the driving TFT 123, and the functional layer 110 emits light according to the amount of current flowing to the functional layer 110 between the cathode 50.

Next, a specific configuration of the EL display device 1 will be described with reference to FIGS.
As shown in FIG. 2, the EL display device 1 is mainly composed of a pixel portion 3 provided on a substrate 20 as a support. Since the EL display device 1 is an active matrix type, although not shown in the drawing, the pixel unit 3 is provided with a plurality of pixel electrodes arranged in a matrix in plan view and corresponding to these pixel electrodes. TFTs, and signal lines and power supply lines connected to the TFTs are provided.
In the present invention, the substrate 20 and the switching TFT and various circuits formed on the substrate 20 as will be described later, and an interlayer insulating film are referred to as a base. (Indicated by reference numeral 200 in FIGS. 3 and 4)

  The pixel unit 3 is partitioned into a real display area 4 (inside the two-dot chain line frame in FIG. 2) in the center and a dummy area 5 (area between the one-dot chain line and the two-dot chain line) around the real display area 4. ing. In the actual display area 4, display areas R, G, and B each having a pixel electrode are arranged in a matrix in a state of being separated from each other at predetermined intervals in the AB direction and the CD direction in the figure. Scan line drive circuits 80 and 80 are arranged on both sides of the actual display area 4 in FIG. These scanning line driving circuits 80 and 80 are actually formed in the lower layer portion of the dummy region 5.

  Further, an inspection circuit 90 is arranged above the actual display area 4 in FIG. The inspection circuit 90 is a circuit for inspecting the operating state of the EL display device 1 and includes, for example, inspection information output means (not shown) for outputting the inspection result to the outside, and is displayed during manufacture or at the time of shipment. It is configured to be able to inspect the quality and defects of the apparatus. The inspection circuit 90 is also formed in the lower layer portion of the dummy region 5.

  The scanning line driving circuit 80 and the inspection circuit 90 are configured such that the driving voltage is applied from a predetermined power supply unit via the driving voltage conducting unit 310 (see FIG. 3) and the driving voltage conducting unit 340 (see FIG. 4). Has been. The drive control signal and drive voltage to the scanning line drive circuit 80 and the inspection circuit 90 are supplied from a predetermined main driver for controlling the operation of the EL display device 1 and the like, as shown in FIG. Transmission and application are performed via the drive voltage conduction unit 350 (see FIG. 4). The drive control signal in this case is a command signal from a main driver or the like related to control when the scanning line drive circuit 80 and the inspection circuit 90 output signals.

As shown in FIGS. 3 and 4, the EL display device 1 has a large number of light emitting elements (organic EL elements) in which a pixel electrode 23, a hole injection layer 70, a light emitting layer 60, and a cathode 50 are stacked on a substrate 200. The buffer layer 210, the gas barrier layer 30 and the like are formed so as to cover them. In this case, the layer composed of the light emitting layer 60 and the hole injection / transport layer 70 corresponds to the functional layer 110 shown in FIG.
For the functional layer sandwiched between the pixel electrode 23 and the cathode 50, the light emitting layer 60 can be used alone. However, by using the hole injection / mailing layer 70 together with the light emitting layer 60, the efficiency of the light emitting element is improved. be able to. Furthermore, in addition to the light emitting layer 60 and the hole injection / transport layer 70, a carrier injection layer or a carrier transport layer such as a hole transport layer, an electron injection layer, and an electron transport layer may be provided. Furthermore, a hole blocking layer (hole blocking layer) and an electron blocking layer (electron blocking layer) may be provided.

  In the case of a bottom emission type EL display device, the substrate 20 constituting the base body 200 is configured to extract emitted light from the substrate 20 side. Therefore, a transparent or translucent substrate 20 is used. For example, glass, quartz, resin (plastic, plastic film) and the like can be mentioned, and a glass substrate is particularly preferable. In the case of the top emission type EL display device, since the emitted light is taken out from the gas barrier layer 30 side opposite to the substrate 20, either a transparent substrate or an opaque substrate can be used. Examples of opaque substrates include ceramics such as alumina, metal sheets such as stainless steel that have been subjected to insulation treatment such as surface oxidation, thermosetting resins and thermoplastic resins, and films thereof (plastic films). It is done.

  A circuit unit 11 including a driving TFT 123 for driving the pixel electrode 23 and the like is formed on the substrate 20, and a large number of light emitting elements (organic EL elements) are provided thereon. As shown in FIG. 5, the light-emitting element is one of an electro-optical material, a pixel electrode 23 that functions as an anode, a hole injection / transport layer 70 that injects / transports holes from the pixel electrode 23, and the like. A light emitting layer 60 containing an organic EL material and a cathode 50 are sequentially formed. Under this configuration, the light emitting element emits light in the light emitting layer 60 by recombination of holes injected from the hole injection / transport layer 70 and electrons supplied from the cathode 50. Yes.

  In the bottom emission type, the pixel electrode 23 is formed of a light-transmitting conductive material such as ITO (indium tin oxide). In the case of the top emission type, it does not need to be translucent and can be formed of an appropriate conductive material. As a material for forming the hole injection / transport layer 70 disposed on the pixel electrode 23, for example, a polythiophene derivative, a polypyrrole derivative, or a doped body thereof can be used. As a specific example, 3,4-polyethylenediosithiophene / polystyrene sulfonic acid (PEDOT / PSS) dispersion, that is, 3,4-polyethylenediosithiophene is dispersed in polystyrene sulfonic acid as a dispersion medium, Further, it can be formed by a liquid phase method using a dispersion in which this is dispersed in water.

As a material for forming the light emitting layer 60, a known light emitting material capable of emitting fluorescence or phosphorescence can be used. Specifically, (poly) fluorene derivative (PF), (poly) paraphenylene vinylene derivative (PPV), polyphenylene derivative (PP), polyparaphenylene derivative (PPP), polyvinyl carbazole (PVK), polythiophene derivative, polymethyl Polysilanes such as phenylsilane (PMPS) are preferably used.
In addition, these polymer materials include polymer materials such as perylene dyes, coumarin dyes, rhodamine dyes, rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6, and quinacridone. It can also be used by doping a low molecular weight material such as. Moreover, it replaces with the polymeric material mentioned above, and a conventionally well-known low molecular material can also be used.
Further, an electron injection layer can be formed on the light emitting layer 60 as necessary.

In the EL display device 1 according to the present embodiment, the hole injection / transport layer 70 and the light emitting layer 60 are lyophilic control layers formed in a lattice shape on the substrate 200 as shown in FIGS. The hole injection / transport layer 70 and the light emitting layer 60 surrounded by the organic bank layer 25 and the organic bank layer 221 constitute an element layer constituting a single light emitting element (organic EL element). .
Here, as shown in FIG. 5, the angle of each wall surface of the opening 221a of the organic bank layer 221 with respect to the surface of the substrate 200 is in the range of 110 degrees to 170 degrees. If it is set as such an angle, when forming the light emitting layer 60 by a wet process, it becomes easy to arrange | position in the opening part 221a, and it is preferable on a manufacturing process.

  As shown in FIGS. 3 and 4, the cathode 50 is formed to have a larger area than the total area of the actual display region 4 and the dummy region 5, and covers both the regions 4 and 5. That is, the cathode 50 is formed on the substrate 200 so as to cover the upper surfaces of the light emitting layer 60 and the organic bank layer 221 and the wall surface forming the outer portion of the organic bank layer 221. The cathode 50 is connected to the cathode wiring 202 formed on the outer periphery of the base body 200 outside the organic bank layer 221 as shown in FIG. A flexible substrate is connected to the cathode wiring 202, and is electrically connected to a driving IC 100 (not shown) (see FIG. 2) via the wiring on the flexible substrate.

  Here, FIG. 6A is a cross-sectional configuration diagram illustrating an enlarged main part of the light emitting element including the cathode 50, and FIG. 6B illustrates an enlarged view of the laminated metal film 51 configuring the cathode 50. FIG. As shown in the figure, in the case of the present embodiment, the cathode 50 has a structure in which a laminated metal film 51 and an electrode film 52 are laminated in order from the light emitting layer 60 side.

  As shown in FIG. 6B, the laminated metal film 51 has a structure in which a plurality of first metal layers 61 and a plurality of second metal layers 62 are alternately laminated. The first metal layer 61 is a layer mainly composed of a so-called low work function metal, and is preferably one or more kinds of metals selected from alkali metals, alkaline earth metals, and rare earth metals. Specifically, it can be formed of a metal material selected from Mg, Na, Li, Cs, Rb, Ca, Ba, Sr, Yb, Er, Tb, Sm, La and the like.

The second metal layer 62 is mainly composed of a high work function metal having a work function higher than that of the low work function metal. For example, a transition metal having good conductivity can be cited as a suitable one. Specifically, it can be formed of a metal material selected from Ag, Au, Zn, Fe, Cr, Al and the like.
The high work function metal forming the second metal layer 62 is preferably a metal selected from the transition metals listed above, but may be a metal having a higher work function than the above low work function metal. It is possible to apply.

  The combination of the first metal layer 61 and the second metal layer 62 in the multilayer metal film 51 having the above-described configuration is preferably a combination of Mg / Ag, Mg / Au, or Li / Al. By adopting these combinations, it is possible to obtain good electron injection properties to the light emitting layer 60.

  In the case of the bottom emission type, the thickness of the laminated metal film 51 is preferably in the range of 20 to 200 nm. When the film thickness is in such a range, the light generated in the light emitting layer 60 is favorably reflected, and the light extraction efficiency to the substrate 20 side can be increased. Even if the film thickness exceeds 200 nm, the effect of the laminated metal film 51 is not substantially changed, but rather, the process of forming the laminated metal film 51 requires a long time, which is not preferable. In the case of the top emission type, the thickness of the laminated metal film 51 is preferably in the range of 5 to 20 nm. This is because the output light from the light emitting layer 60 needs to be transmitted well. If the film thickness is less than 5 nm, the effect of improving the electron injection property to the light emitting layer 60 by providing the laminated metal film 51 cannot be sufficiently obtained.

  The thicknesses of the first metal layer 61 and the second metal layer 62 are appropriately varied depending on the composition of the laminated metal film 51 to be formed. For example, magnesium (Mg) is used as the first metal layer 61 and the second metal When the laminated metal film 51 having an Mg / Ag composition ratio of 1:10 is formed using silver (Ag) as the layer 62, the layer thickness of the first metal layer 61 is, for example, 0.1 nm, The first metal layer 61 and the second metal layer 62 may be alternately stacked until the metal layer 62 has a thickness of 1 nm and reaches a predetermined total thickness.

  The thickness of one layer of the first metal layer 61 and the second metal layer 62 is preferably 10 nm or less. More preferably, the layer thickness is 5 nm or less, and more desirably 1 nm or less. When the layer thickness exceeds 10 nm, a coating film that covers the lower layer may be formed depending on the constituent elements. When the coating film is formed in this way, the conductivity and electron injection property may be lowered. The layer thickness is preferably as thin as possible. However, depending on the performance of the film forming apparatus, there is a possibility of non-uniform deposition on the substrate, and the time for forming the metal laminated film 51 becomes longer. Since there is a possibility of lowering the production efficiency, it is not preferable to make it too thin.

  In the laminated metal film 51 having the laminated structure, it is preferable that a first metal layer 61 mainly composed of the low work function metal is disposed in a layer adjacent to the light emitting layer 60. With such a configuration, even in the structure in which the first metal layer 61 made of a low work function metal and the second metal layer 62 made of a high work function metal are stacked, good electrons to the light emitting layer 60 can be obtained. Injectability can be obtained, and the light-emitting element can emit light with high efficiency.

  On the other hand, it is preferable that a second metal layer 62 mainly composed of a high work function metal is disposed on the surface layer of the laminated metal film 51 opposite to the light emitting layer 60. With such a configuration, the electrode film 52 comes into contact with the high work function metal, which is more stable than the low work function metal and has good conductivity. Smooth electron transport to the laminated metal film 51 can be realized. If the first metal layer 61 is disposed on the light emitting layer 60 side and the second metal layer 62 is disposed on the electrode film 52 side, the light emitting layer is formed from the cathode wiring through the electrode film 52 and the laminated metal film 51. Electron transport in the route up to 60 is smoothly performed, and the light emitting element can emit light with higher efficiency.

  As a material of the electrode film 52 constituting the upper layer side of the cathode 50 in the figure, a high work function metal constituting the second metal layer 62, that is, a transition metal having good conductivity can be used. The material for forming the electrode film 52 may be the same metal material as that of the second metal layer 62 of the laminated metal film 51 or may be a different material. In the case of the top emission type, since it needs to be light transmissive, a light transmissive conductive material such as ITO is used for the electrode film 52.

  In the laminated metal film 51 according to the present embodiment, the ratio (d1 / d2) between the layer thickness d1 of the first metal layer 61 adjacent to each other (see FIG. 6B) and the layer thickness d2 of the second metal layer 62 is obtained. However, it can be set as the structure which differs continuously or partially in the film thickness direction (lamination direction) of the lamination | stacking metal film 51. FIG. For example, if the layer thickness ratio (d1 / d2) is increased at the portion of the laminated metal film 51 on the light emitting layer 60 side, the ratio of the first metal layer 61 mainly composed of a low work function metal is increased. Electron injection properties from the metal film 51 to the light emitting layer 60 can be improved. Further, if the layer thickness ratio (d1 / d2) is reduced at the site opposite to the light emitting layer 60, the ratio of the high work function metal is increased, so that the electron transport property from the electrode film 52 is improved.

  Further, the layer thickness ratio (d1 / d2) of the portion adjacent to the light emitting layer 60 is increased, the layer thickness ratio (d1 / d2) of the portion adjacent to the electrode film 52 is decreased, and further, the layer thickness at the intermediate portion thereof. The ratio (d1 / d2) may be an intermediate ratio between the two end portions. In this case, the number of times the layer thickness ratio (d1 / d2) is changed in the forming process is smaller than when the layer thickness ratio (d1 / d2) is continuously changed in the film thickness direction. This is convenient in terms of simplification of the manufacturing process and ease.

As described above, as the cathode 50, a plurality of first metal layers 61 mainly composed of low work function metals and second metal layers 62 mainly composed of high work function metals are alternately provided on the lower layer side (light emitting layer 60 side). Since the laminated metal film 51 is provided with the laminated layers, the light emitting device according to the present embodiment can efficiently inject electrons from the electrode film 52 to the light emitting layer 60 through the laminated metal film 51, and has high efficiency. It is a light emitting element capable of emitting light.
Conventional cathodes using Li / Al-based materials, etc., had a problem that it was difficult to control the composition ratio of the two elements because the film was formed by co-evaporation in which two element vapor deposition species were simultaneously deposited. However, since the first metal layer 61 and the second metal layer 62 are alternately stacked as in this embodiment, the composition ratio of the entire stacked metal film 51 can be controlled with high accuracy. It has become. Furthermore, since a laminated film having an appropriate composition ratio can be formed on the light emitting layer 60 side and the opposite electrode film 52 side, a high performance cathode having good conductivity and electron injecting property can be obtained. it can.

  A cathode protective layer 55 as shown in FIG. 6A may be formed on the upper layer side of the cathode 50. The cathode protective layer 55 is formed of an inorganic compound such as a silicon compound or a metal compound. By providing the cathode protective layer 55, the cathode 50 can be prevented from being corroded during the manufacturing process. Further, by covering the cathode 50 with the cathode protective layer 55 made of an inorganic compound, it is possible to satisfactorily prevent oxygen and the like from entering the cathode 50 and the light emitting layer 60. The cathode protective layer 55 is preferably formed to a thickness of about 10 nm to 300 nm, and preferably extends to a region covering the insulating layer 284 on the outer peripheral portion of the substrate 200.

  On the cathode 50 (or the cathode protective layer 55), a buffer layer 210 that covers the cathode 50 in a range wider than the organic bank layer 221 is provided. The buffer layer 210 is formed so as to flatten a region on the cathode 50 having an uneven shape that follows the shape of the organic bank layer 221. The buffer layer 210 has a function of relieving the warp generated from the base 200 side and the stress generated by the volume change, and preventing the cathode 50 and the like from peeling off from the organic bank layer 221. Further, since the upper surface of the buffer layer 210 is substantially flattened, the flatness of the gas barrier layer 30 formed thereon can be maintained, and cracks of the gas barrier layer 30 due to stress concentration can be prevented.

  As a material for forming the buffer layer 210, an organic compound material containing an epoxy resin, an acrylic resin, a silicone resin, polyurethane, polyether, polyester, or the like as a main component is preferable. These organic compound materials can be diluted with an organic solvent to adjust the viscosity, and the following reaction materials are mixed into epoxy oligomers, acrylic oligomers, polyurethanes, etc. to give photocuring properties or thermosetting properties. Convenience is high in point that we can do. As the reaction material, an isocyanate compound such as tolylene diisocyanate that reacts with moisture, an alkoxysilane compound such as methyltrimethoxysilane, or a photopolymerization reagent such as aminoketone, hydroxyketone, or bisacylphosphine oxide is used. It is good. If these reaction materials are mixed, the reaction can proceed by heat treatment or light irradiation at a relatively low temperature, and the buffer layer 210 can be cured, so that the heat resistant upper limit temperature of the light emitting layer 60 (about 120 ° C. to 140 ° C.). The buffer layer 210 can be cured at the following temperature, and adverse effects on the light emitting layer 60 due to heating can be suppressed. Fine particles may be added to the buffer layer forming material for the purpose of preventing shrinkage during dry polymerization.

  On the buffer layer 210, the gas barrier layer 30 is provided so as to cover the portion where the buffer layer 210 is exposed. The gas barrier layer 30 extends to the insulating layer 284 on the outer periphery of the base body 200. The gas barrier layer 30 disposed on the insulating layer 284 may be in contact with the cathode protective layer 55 described above.

The gas barrier layer 30 is a layer provided to prevent oxygen and moisture from entering the inner cathode 50 and the light emitting layer 60 and to suppress deterioration of the cathode 50 and the light emitting layer 60 due to oxygen and moisture. It is formed by. As a material for forming the gas barrier layer 30, a silicon compound, that is, silicon nitride, silicon oxynitride, silicon oxide, or the like is preferably used. In addition to silicon compounds, for example, alumina, tantalum oxide, titanium oxide, and other ceramics can be used as the forming material.
If the gas barrier layer 30 is formed of an inorganic compound, the adhesion between the gas barrier layer 30 and the cathode 50 can be improved, particularly when the electrode film 52 on the upper layer side of the cathode 50 is ITO. Since the dense gas barrier layer 30 having no oxygen can be formed, the barrier property against oxygen and moisture can be further improved.

As the gas barrier layer 30, for example, a structure in which layers made of two or more materials selected from the above-described silicon compounds are stacked can be applied. For example, a structure in which a silicon nitride layer and a silicon oxynitride layer are formed in this order from the cathode 50 side, or a structure in which a silicon oxynitride layer and a silicon oxide layer are stacked in this order from the cathode 50 side can be employed.
A structure in which two or more silicon oxynitride layers having different composition ratios are stacked can also be applied. In this case, it is preferable that the oxygen concentration of the silicon nitride layer on the inner side (cathode 50 side) is lower than the oxygen concentration of the outer silicon nitride layer. Thus, by lowering the oxygen concentration of the silicon nitride layer on the cathode 50 side, oxygen in the gas barrier layer 30 passes through the cathode 50 and reaches the light emitting layer 60 on the inner side, thereby deteriorating the light emitting layer 60. This can also be prevented, and the life of the light emitting layer 60 can be extended.

  The gas barrier layer 30 may not have a laminated structure, but may have a non-uniform composition and particularly a structure in which the oxygen concentration changes continuously or discontinuously. Also in this case, it is preferable for the reason described above that the oxygen concentration on the cathode 50 side is lower than the oxygen concentration on the outside.

The layer thickness of the gas barrier layer 30 is preferably in the range of 10 nm to 500 nm. If the thickness is less than 10 nm, holes may be partially formed due to film defects or film thickness variations, which may impair gas barrier properties. Further, if the thickness exceeds 500 nm, cracking due to stress tends to occur.
In the case of constituting a top emission type EL display device, the gas barrier layer 30 needs to be translucent. In this case, it is preferable that the light transmittance in the visible light region is, for example, 80% or more by appropriately adjusting the material and film thickness.

On the gas barrier layer 30, as shown in FIGS. 5 and 6A, a protective layer 204 that covers the gas barrier layer 30 is provided. The protective layer 204 includes an adhesive layer 205 and a surface protective layer 206 disposed on the gas barrier layer 30 side.
The adhesive layer 205 fixes the surface protective layer 206 on the gas barrier layer 30 and exhibits a buffering function against mechanical shock from the outside. The adhesive layer 205 is made of, for example, a resin material such as urethane, acrylic, epoxy, or polyolefin, and is formed as an adhesive made of a material that is softer and has a lower glass transition point than the surface protective layer 206 described later. It has been done. It is preferable to add a silane coupling agent or alkoxysilane to such an adhesive, and in this way, the adhesion between the formed adhesive layer 205 and the gas barrier layer 30 can be improved. In addition, the buffer function against mechanical shock is increased.
In particular, when the gas barrier layer 30 is formed of a silicon compound, the adhesion to the gas barrier layer 30 can be improved by a silane coupling agent or alkoxysilane, and thus the gas barrier property of the gas barrier layer 30 is improved. be able to.

  The surface protective layer 206 is provided on the adhesive layer 205 and constitutes the surface side of the protective layer 204, and has functions such as pressure resistance, wear resistance, external light antireflection, gas barrier properties, and ultraviolet blocking properties. It is a layer having at least one. Specifically, it can be formed of a polymer layer (plastic film), a DLC (diamond-like carbon) layer, glass or the like. Note that in the case of a top emission type EL display device, both the surface protective layer 206 and the adhesive layer 205 need to be light-transmitting.

Next, the circuit unit 11 provided on the lower layer side of the light emitting element will be described with reference to FIG. The circuit unit 11 is formed on the substrate 20 and constitutes a base body 200. A base protective layer 281 mainly composed of SiO ₂ is formed on the surface of the substrate 20, and a silicon layer 241 is formed thereon. A gate insulating layer 282 mainly composed of SiO ₂ and / or SiN is formed on the surface of the silicon layer 241.

Of the silicon layer 241, a region overlapping with the gate electrode 242 with the gate insulating layer 282 interposed therebetween forms a channel region 241a. The gate electrode 242 is a part of the scanning line 101 (not shown). On the other hand, a first interlayer insulating layer 283 mainly composed of SiO ₂ is formed on the surface of the gate insulating layer 282 that covers the silicon layer 241 and on which the gate electrode 242 is formed.

In the silicon layer 241, a low concentration source region 241b and a high concentration source region 241S are formed on the source side of the channel region 241a, while a low concentration drain region 241c and a high concentration drain region are formed on the drain side of the channel region 241a. A region 241D is provided to form a so-called LDD (Light Doped Drain) structure.
The high concentration source region 241 </ b> S is connected to the source electrode 243 through a contact hole 243 a that is opened across the gate insulating layer 282 and the first interlayer insulating layer 283. The source electrode 243 is configured as a part of the above-described power supply line 103 (see FIG. 1, extending in the direction perpendicular to the paper surface at the position of the source electrode 243 in FIG. 5). On the other hand, the high-concentration drain region 241D is connected to the drain electrode 244 made of the same layer as the source electrode 243 through a contact hole 244a opened across the gate insulating layer 282 and the first interlayer insulating layer 283.

The upper layer of the first interlayer insulating layer 283 on which the source electrode 243 and the drain electrode 244 are formed is covered with a second interlayer insulating layer 284 mainly composed of, for example, an acrylic resin component. The second interlayer insulating layer 284 can be made of a material other than an acrylic insulating film, such as SiN or SiO ₂ . A pixel electrode 23 made of ITO is formed on the surface of the second interlayer insulating layer 284, and a part thereof is connected to the drain electrode 244 through a contact hole 23 a provided in the second interlayer insulating layer 284. . That is, the pixel electrode 23 is connected to the high concentration drain region 241D of the silicon layer 241 through the drain electrode 244.

  Note that TFTs (driving circuit TFTs) included in the scanning line driving circuit 80 and the inspection circuit 90, that is, N-channel type or P-channel type TFTs constituting an inverter included in the shift register, for example, among these driving circuits. The structure is the same as that of the driving TFT 123 except that it is not connected to the pixel electrode 23.

On the surface of the second interlayer insulating layer 284 on which the pixel electrode 23 is formed, the pixel electrode 23 and the above-described lyophilic control layer 25 and organic bank layer 221 are provided. The lyophilic control layer 25 is mainly made of a lyophilic material such as SiO ₂ , and the organic bank layer 221 is made of acrylic or polyimide. A hole injection / transport layer 70 and a light-emitting layer 60 are formed on the pixel electrode 23 inside the opening 221 a surrounded by the opening 25 a provided in the lyophilic control layer 25 and the organic bank layer 221. They are stacked in order. In addition, “lyophilic” of the lyophilic control layer 25 in the present embodiment means that the lyophilic property is higher than at least materials such as acrylic and polyimide constituting the organic bank layer 221.
The circuit portion 11 is configured by the layers up to the second interlayer insulating layer 284 on the substrate 20 described above.

  Here, in the EL display device 1 of the present embodiment, each light emitting layer 60 is formed so that the light emission wavelength bands correspond to the three primary colors of light in order to perform color display. For example, as the light emitting layer 60, a red light emitting layer whose light emission wavelength band corresponds to red, a green light emitting layer corresponding to green, and a blue organic EL layer corresponding to blue, respectively, display regions R, G, A configuration in which one pixel that performs color display with these display regions R, G, and B is formed in B can be applied. Further, a BM (black matrix) (not shown) in which metallic chromium is formed by sputtering or the like is formed between the organic bank layer 221 and the lyophilic control layer 25 at the boundary between the color display regions. .

(Method for manufacturing EL display device)
Next, as an embodiment of the method for manufacturing the electro-optical device according to this embodiment, a method for manufacturing the EL display device 1 according to the previous embodiment will be described.

<Vapor deposition equipment>
First, prior to the description of the manufacturing method, the configuration of the three types of vapor deposition apparatuses 300, 400, and 500 that can be suitably used for manufacturing the EL display device 1 will be described. FIG. 7 shows a vapor deposition apparatus 300, FIG. 8 shows a vapor deposition apparatus 400, and FIG. 9 shows a vapor deposition apparatus 500, respectively.

[First configuration example]
First, the vapor deposition apparatus 300 as a 1st structural example of a vapor deposition apparatus is demonstrated with reference to FIG. 7A, the vapor deposition apparatus 300 includes a box-shaped film formation container 310, two vapor deposition sources 331 and 332 accommodated therein, and these vapor deposition sources 331 and 332. The main components are two shutters 321 and 322 provided corresponding to the above. The film formation container 310 is mainly composed of a vapor deposition chamber 311 containing vapor deposition sources 331, 332 and the like, and a substrate carry-in portion 312 and a substrate carry-out portion 313 are provided above the vapor deposition chamber 311. The substrate 20 is supported in the film formation container 310 between the substrate carry-in portion 312 and the substrate carry-out portion 313 and is used for the film formation step. A vacuum pump 316 is connected to a side wall near the bottom of the vapor deposition chamber 311 via a gate valve 315.
Note that the substrate carry-in portion 312 and the substrate carry-out portion 313 can introduce / lead out the substrate 20 while keeping the inside of the vapor deposition chamber 311 in a vacuum state, and continuously form films on the plurality of substrates 20. It can be processed.

  Two vapor deposition sources 331 and 332 are disposed at the bottom of the vapor deposition chamber 311, and heaters (heating means) 337 and 337 are disposed on the back side (the lower surface side in the drawing) of these vapor deposition sources 331 and 332, respectively. The evaporation source 331 includes a boat 334 and a film formation material 341 placed on the boat 334, and the evaporation source 332 includes a boat 334 and a film formation material 342 placed on the boat 334. Yes. In these vapor deposition sources 331, 332, the boat 334 is heated by the heater 337 so that the vapor deposition species are released from the film forming materials 341, 342.

  Between the vapor deposition sources 331 and 332 and the base 20, shutters (shielding means) 321 and 322 are arranged corresponding to the respective vapor deposition sources. FIG. 7B is a plan view of the vapor deposition sources 331 and 332 viewed from the substrate 20 side. The shutters 321 and 322 are plate-like members each having a semicircular shape in plan view, and both of them are substantially sandwiched by a partition wall member 318 erected so as to isolate the vapor deposition sources 331 and 332 in the vapor deposition chamber 311. It arrange | positions so that circular shape may be comprised. The shutters 321 and 324 are pivotally supported by driving shafts 323 and 322 extending in the vertical direction in FIG. 7A at the upper end of FIG. The drive shafts 323 and 324 are connected to the film formation control unit 350, rotate around the axis by a drive signal supplied from the film formation control unit 350, and rotate the shutters 321 and 322 within their plate surfaces. It is possible.

  As shown in FIG. 7B, the shutters 321 and 322 can be opened and closed between the vapor deposition sources 331 and 332 and the substrate 20 by the rotation operation. Further, the film formation control means 350 can operate the shutters 321 and 322 in conjunction with each other. As shown in FIG. 7B, the shutter 321 is set to the “open” position and the shutter 322 is set to the “closed” position. It can be operated to switch between the state and the state in which the shutter 321 indicated by a two-dot chain line in the drawing is in the “closed” position and the shutter 322 in the “open” position. That is, when the shutter 321 is in the “open” position and the shutter 322 is in the “closed” position, only the vapor deposition species released from the film forming material 341 of the vapor deposition source 331 can be selectively deposited on the substrate 20. Conversely, when the shutter 321 is in the “closed” position and the shutter 322 is in the “open” position, only the vapor deposition species released from the film forming material 342 of the vapor deposition source 332 can be selectively deposited on the substrate 20. it can.

[Second configuration example]
Next, the vapor deposition apparatus 400 as a 2nd structural example of a vapor deposition apparatus is demonstrated with reference to FIG. FIG. 8A is a side sectional view of the vapor deposition apparatus 400. In FIG. 8, components having the same reference numerals as those in FIG. 7 are similar components, and detailed description thereof will be omitted below.

  The vapor deposition apparatus 400 shown in FIG. 8 includes a shutter (shielding means) 421 provided between the vapor deposition sources 331 and 332 and the substrate 20 disposed in the film formation container 310, and a film formation control means 450 connected thereto. The other configurations are the same as those of the previous vapor deposition apparatus 300. FIG. 8B is a plan view of the vapor deposition sources 331 and 332 viewed from the substrate 20 side. As shown in FIGS. 8A and 8B, the shutter 421 is a disk-like member, and an opening 421a having a rectangular shape in plan view is provided in the plate surface. The shutter 421 is supported by the drive shaft 423 at its center, and the drive shaft 423 rotates around the axis by a drive signal from the film formation control unit 450 connected thereto, and rotates the shutter 421 in the circumferential direction. It is supposed to let you. The opening 421a is configured such that the film forming materials 341 and 342 placed on the vapor deposition sources 331 and 332 are disposed therein at predetermined positions.

  In the vapor deposition apparatus 400 having the above configuration, the position of the opening 421a is moved by rotating the shutter 421 by the drive shaft 423, and any one of the vapor deposition sources 331 and 332 faces the substrate 20 (shutter "open"). Position) and a state hidden from the substrate 20 (shutter “closed” position) can be switched. When the shutter 421 is in the “open” position with respect to the vapor deposition source 331, it is in the “closed” position with respect to the vapor deposition source 332, and only the vapor deposition species released from the film forming material 341 are selectively formed on the substrate 20. It is deposited on. Conversely, when the shutter 421 is in the “open” position with respect to the vapor deposition source 332, only the film forming material 342 is selectively deposited on the substrate 20.

[Third configuration example]
Next, the vapor deposition apparatus 500 as a 3rd structural example of a vapor deposition apparatus is demonstrated with reference to FIG. FIG. 9 is a side sectional view of the vapor deposition apparatus 500. In FIG. 9, components having the same reference numerals as those in FIGS. 7 to 8 are components having the same configuration as the previous embodiment.
The vapor deposition apparatus 500 shown in FIG. 9 is mainly composed of a box-shaped film formation container 510 and two vapor deposition sources 331 and 332. The film forming container 510 is provided with a partition member 518 that partitions the inside thereof, and includes two vapor deposition chambers 501 and 502 that are partitioned by the partition member 518. The vapor deposition chambers 501 and 502 accommodate vapor deposition sources 331 and 332, respectively. A substrate carry-in unit 512 and a substrate carry-out unit 513 are provided above the vapor deposition chambers 501 and 502 in the figure, and the substrate 20 is disposed between the substrate carry-in unit 512 and the substrate carry-out unit 513 for vapor deposition processing. Provided.
Note that the vapor substrate carrying-in unit 512 and the substrate carrying-out unit 513 are configured to allow introduction / extraction of the substrate 20 while the vapor deposition chambers 501 and 502 are maintained in a vacuum state, similarly to the previous vapor deposition apparatus 300. .

Further, a substrate transport means (not shown) for supporting and moving the substrate 20 above the film forming chambers 501 and 502 is disposed in the film forming container 510, and this substrate transport means is driven by it. A film formation control means 550 for controlling is connected.
Then, the substrate transport means moves the substrate 20 to a predetermined position by a drive signal supplied from the film formation control means 550. That is, the substrate 20 can be moved to a position facing the vapor deposition source 331 in the film formation chamber 501 and a position facing the vapor deposition source 332 in the film formation chamber 502.

  In the vapor deposition apparatus 500 having the above configuration, the vapor deposition species to be deposited on the substrate 20 can be selected by moving the substrate 20 by the film formation control means 550. That is, when the substrate 20 is placed on the vapor deposition chamber 501, only the vapor deposition species released from the film forming material 421 of the vapor deposition source 331 are selectively deposited on the substrate 20. At this time, even if the vapor deposition source is emitted from the vapor deposition source 332, it is not deposited on the substrate 20 because it is shielded by the partition member 518. If the substrate 20 is placed above the film formation chamber 502, only the vapor deposition species emitted from the film formation material 342 of the vapor deposition source 332 are selectively deposited on the substrate 20.

<Manufacturing method>
Next, a method for manufacturing the EL display device 1 will be described with reference to FIGS. Each cross-sectional view shown in FIGS. 10 to 12 corresponds to the cross-sectional view taken along the line AB in FIG. Further, the process of forming the circuit portion 11 on the surface of the substrate 20 is not different from the conventional technique, and thus the description thereof is omitted.

First, as shown in FIG. 10A, after forming a conductive film to be the pixel electrode 23 so as to cover the entire surface of the substrate 20 on which the circuit portion 11 is formed, this transparent conductive film is patterned. Thus, the pixel electrode 23 is formed. The pixel electrode 23 is electrically connected to the drain electrode 244 through a contact hole 23 a penetrating the second interlayer insulating layer 284. At the same time as the pixel electrode 23 is formed, a dummy pattern 26 in the dummy area is also formed.
3 and 4, the pixel electrode 23 and the dummy pattern 26 are collectively referred to as the pixel electrode 23. However, the dummy pattern 26 is not connected to the lower-layer metal wiring via the second interlayer insulating layer 284. It is arranged in an isolated island shape. The planar shape is substantially the same as the shape of the pixel electrode 23 formed in the actual display area, but may be a structure different from the shape of the pixel electrode 23 formed in the display area.

Next, as shown in FIG. 10B, a lyophilic control layer 25 that is an insulating layer is formed on the pixel electrode 23, the dummy pattern 26, and the second interlayer insulating film. In the pixel electrode 23, the lyophilic control layer 25 is formed in such a manner that a part of the pixel electrode 23 is opened, and the hole 25a (see also FIG. 3) is formed so that holes can move from the pixel electrode 23. . Conversely, in the dummy pattern 26 not provided with the opening 25a, the insulating layer (lyophilic control layer) 25 is formed to cover the hole movement blocking layer so as not to cause hole movement.
Subsequently, in the lyophilic control layer 25, a BM (black matrix) (not shown) is formed in a concave portion located between two different pixel electrodes 23. Specifically, the concave portion of the lyophilic control layer 25 is formed by sputtering using metallic chromium.

  Then, as shown in FIG. 10C, an organic bank layer 221 is formed so as to cover a predetermined position of the lyophilic control layer 25, specifically, the BM described above. As a specific method for forming an organic bank layer, for example, an organic resin is formed by applying a resist such as acrylic resin or polyimide dissolved in a solvent by various coating methods such as a spin coating method or a slit die coating method. Further, this organic layer is patterned using a photolithography technique and an etching technique, and an opening 221a is formed in the organic layer, thereby forming an organic bank layer 221 having a wall surface in the opening 221a. The constituent material of the organic layer may be any material as long as it does not dissolve in the ink solvent described later and is easily patterned by etching or the like. In addition, the organic bank layer 221 includes at least a layer positioned above the drive control signal conducting unit 320.

Next, a region showing lyophilicity and a region showing liquid repellency are formed on the surface of the organic bank layer 221. In the present embodiment, each region is formed by plasma processing. Specifically, in the plasma treatment, the upper surface of the organic bank layer 221, the wall surface of the opening 221a, the electrode surface 23c of the pixel electrode 23, and the upper surface of the lyophilic control layer 25 are made lyophilic, respectively. The ink making step includes an ink repellent step, an ink repellent step for making the upper surface of the organic bank layer 221 and the wall surface of the opening 221a liquid repellent, and a cooling step.
That is, a base material (substrate 20 including a bank or the like) is heated to a predetermined temperature, for example, about 70 to 80 ° C., and then plasma treatment using oxygen as a reactive gas in an atmospheric atmosphere (O ₂ plasma treatment) as an ink-philic step I do. Next, as an ink repellent process, a plasma process using CF ₄ as a reaction gas (CF ₄ plasma process) is performed in an air atmosphere, and then the substrate heated for the plasma process is cooled to room temperature. In addition, lyophilicity and liquid repellency are imparted to predetermined locations.
In this CF ₄ plasma treatment, the electrode surface 23c of the pixel electrode 23 and the lyophilic control layer 25 are somewhat affected, but the structure of the ITO that is the material of the pixel electrode 23 and the lyophilic control layer 25. Since materials such as SiO ₂ and TiO ₂ have poor affinity for fluorine, the hydroxyl group imparted in the ink-philic process is not substituted with the fluorine group, and the lyophilic property is maintained.

Next, the hole injection / transport layer 70 is formed by the hole injection / transport layer formation step. In this hole injection / transport layer forming step, a hole injection / transport layer material is applied onto the electrode surface 23c by, for example, a droplet discharge method such as an ink jet method or a slit die coating method, and then a drying process and a heat treatment are performed. Then, the hole injection / transport layer 70 is formed on the electrode 23.
In addition, after this hole injection / transport layer formation process, in order to prevent oxidation of the hole injection / transport layer 70 and the organic light emitting layer 60, it is preferable to perform in inert gas atmosphere, such as nitrogen atmosphere and argon atmosphere.

When the hole injection / transport layer material is selectively applied by, for example, an ink jet method, first, the hole injection / transport layer material is filled in the ink jet head (not shown), and the discharge nozzle of the ink jet head is made lyophilic. The amount of liquid per droplet was controlled from the discharge nozzle while moving the inkjet head and the base material (substrate 20) relative to the electrode surface 23c located in the opening 25a formed in the control layer 25. A droplet is discharged onto the electrode surface 23c. Then, the discharged liquid droplets are dried, and the hole injection / transport layer 70 is formed by evaporating the dispersion medium and the solvent contained in the hole injection / transport layer material.
Here, the droplets ejected from the ejection nozzle spread on the electrode surface 23c that has been subjected to the lyophilic treatment, and are filled in the opening 25a of the lyophilic control layer 25. On the other hand, on the upper surface of the organic bank layer 221 that has been subjected to the ink repellent treatment, droplets are repelled and do not adhere. Therefore, even if the droplet is discharged from the predetermined discharge position and discharged onto the upper surface of the organic bank layer 221, the upper surface is not wetted by the droplet, and the repelled droplet is opened in the lyophilic control layer 25. Roll into part 25a.

Next, the organic light emitting layer 60 is formed by the light emitting layer forming step. In this light emitting layer forming step, the light emitting layer forming material is ejected onto the hole injection / transport layer 70 by, for example, an ink jet method, and then subjected to a drying process and a heat treatment, whereby openings formed in the organic bank layer 221 are formed. An organic light emitting layer 60 is formed in 221a. In this light emitting layer forming step, a nonpolar solvent insoluble in the hole injecting / transporting layer 70 is used as a solvent used for the light emitting layer forming material in order to prevent re-dissolution of the hole injecting / transporting layer 70.
In this light emitting layer forming step, for example, a blue (B) light emitting layer forming material is selectively applied to a blue display region by an inkjet method, dried, and then similarly treated with green (G) and red (R ) Is also selectively applied to the display area and dried.

  Next, as shown in FIG. 11D, the cathode 50 is formed by a cathode forming step. In this cathode forming step, a plurality of first metal layers 61 mainly composed of low work function metals and second metal layers 62 mainly composed of high work function metals shown in FIG. A laminated metal film forming step for forming the film 51 and an electrode film forming step for forming the electrode film 52 on the laminated metal film 51 are performed.

The laminated metal film forming step is preferably performed using any one of the vapor deposition apparatuses 300, 400, and 500 shown in FIGS. 7 to 9, but the film forming apparatus applicable to the present manufacturing method is not limited. Absent. First, a laminated metal film forming process using the vapor deposition apparatus 300 shown in FIG. 7 will be described.
In order to form the laminated metal film 51 using the vapor deposition apparatus 300, first, for example, magnesium (Mg) is prepared as the film forming material 341 of the vapor deposition source 331 and placed on the boat 334, and the film formation of the vapor deposition source 332 is performed. Silver (Ag) is prepared as the material 342 and placed on the boat 334. At this time, the shutters 321 and 322 are both set to the “closed” position.

  Next, the film formation container 310 is sealed, the vacuum pump 316 is operated, and the gate valve 315 is released to maintain the film formation container 310 at a predetermined degree of vacuum. Thereafter, the substrate 20 is introduced into the film forming container 310 via the substrate carrying-in portion 312 and supported at a predetermined position shown in FIG.

  When the above preparation is completed, the heaters 337 of the vapor deposition sources 331 and 332 are operated to heat the film forming materials 341 and 342 to a predetermined temperature. When the boats 334 and 334 reach a predetermined temperature and evaporation from the film forming materials 341 and 342 is started, the film forming control unit 350 starts the operation of the shutters 321 and 322 and stacks them on the substrate 20. A metal film 51 is formed. In other words, the shutters 321 and 332 are alternately opened and closed for a predetermined time in a state where Mg and Ag vapors (vapor deposition seeds) are discharged from the vapor deposition sources 331 and 332, respectively, so that Mg having a predetermined film thickness is formed on the substrate 20. Layers (first metal layer 61) and Ag layers (second metal layer 62) are alternately stacked. When the laminated metal film 51 reaches a predetermined film thickness (for example, 20 nm), the operations of the shutters 321 and 322 are stopped, and the substrate 20 is transported from the substrate unloading portion 313 to the outside of the container.

  Thus, by using the vapor deposition apparatus 300, the laminated metal film 51 can be formed while controlling the layer thicknesses of the first metal layer 61 and the second metal layer 62 with high accuracy, and easily having a desired composition ratio. The laminated metal film 51 (cathode 50) can be obtained. Therefore, according to the manufacturing method according to the present embodiment, the composition is controlled with high accuracy, a cathode having desired characteristics can be formed with good reproducibility, and a light emitting device capable of emitting light efficiently can be obtained. Can do.

  Further, by adjusting the opening / closing time of the shutters 321 and 322, the layer thicknesses of the first metal layer 61 and the second metal layer 62 to be formed can be arbitrarily adjusted. It is also easy to form a laminated metal film having a high Mg (first metal layer 61) content and having a high work function Ag content on the electrode film 52 side.

  Further, since the vapor deposition apparatus 300 forms the vapor deposition species emitted from the vapor deposition sources 331 and 332 independently of each other, a film thickness monitor for monitoring each film formation rate is provided for each vapor deposition source 331 and 332. If provided, the deposition rate can be easily adjusted even if the deposition rate of each vapor deposition source changes with time, so that a uniform laminated metal film 51 can be obtained over a long period of time. It has become.

  Further, when the vapor deposition apparatus 400 shown in FIG. 8 is used, after the inside of the film formation container 310 is evacuated and the substrate 20 is introduced into a predetermined position, the previous vapor deposition is performed until the process of starting heating the vapor deposition sources 331 and 332. This is the same as the device 300. However, in these steps, the opening 421a of the shutter 421 disposed between the vapor deposition sources 331 and 332 and the substrate 20 is held at a position not facing the vapor deposition sources 331 and 332 (that is, a “closed” position). Keep it.

  When the preparation for film formation is completed, the film formation control unit 450 drives the drive shaft 423 to rotate the shutter 421, for example, to arrange the opening 421 a on the front surface of the vapor deposition source 331. Then, the Mg vapor emitted from the vapor deposition source 331 reaches the substrate 20 through the opening 421a, and an Mg layer (first metal layer 61) is formed on the substrate 20. Next, when an Mg layer having a predetermined layer thickness is formed on the substrate 20, the shutter 421 is rotated to place the opening 421 a in front of the other vapor deposition source 332, and Ag vapor released from the vapor deposition source 332 is emitted. The Ag layer (second metal layer 62) is stacked on the Mg layer by reaching the substrate 20. Thereafter, by alternately repeating the Mg layer forming step and the Ag layer forming step, a laminated metal film 51 made of an Mg / Ag laminated film having a predetermined thickness can be formed on the substrate 20.

  Thus, the vapor deposition apparatus 400 can also form the laminated metal film 51 equivalent to the previous vapor deposition apparatus 300, and the same effect as the case where the vapor deposition apparatus 300 is used can be acquired.

  Furthermore, when the vapor deposition apparatus 500 shown in FIG. 9 is used, the inside of the film formation container 510 is evacuated, and the substrate 20 is introduced from the substrate carry-in portion 512 to a predetermined position in the film formation container. Then, when the release of the vapor deposition species from the vapor deposition sources 331 and 332 is started, an operation of moving the substrate 20 between the vapor deposition chamber 501 and the vapor deposition chamber 502 by the film formation control unit 550 is started. That is, when the substrate 20 faces the vapor deposition source 331 in the vapor deposition chamber 501, only Mg vapor released from the vapor deposition source 331 reaches the substrate 20 to form an Mg layer (first metal layer 61) on the surface thereof. In a state where the substrate 20 is moved to a position facing the vapor deposition source 332 of the other vapor deposition chamber 502, only the Ag vapor emitted from the vapor deposition source 332 reaches the substrate 20 and an Ag layer (second metal layer 62) is formed on the surface thereof. ).

Then, by repeating the operation of moving the substrate 20 between the deposition chambers, the laminated metal film 51 having a structure in which Mg layers and Ag layers having a predetermined thickness are alternately laminated can be formed on the substrate 20. it can.
Thus, the vapor deposition apparatus 500 can also form the laminated metal film 51 equivalent to the previous vapor deposition apparatuses 300 and 400, and the same effect as the case where the vapor deposition apparatuses 300 and 400 are used can be obtained.

  If the laminated metal film 51 is formed by the above process, an electrode film 52 is then formed on the surface of the laminated metal film 51. In forming the electrode film 52, the same vapor deposition apparatus as that used for forming the laminated metal film 51 can be used. Further, when the electrode film 51 is formed of the same material as that of the second metal layer 62. The electrode film 52 can also be formed using the vapor deposition source 332 of the second metal layer 62 in succession to the step of forming the laminated metal film 51. Thus, if the laminated metal film 51 and the electrode film 52 are continuously formed by the same vapor deposition apparatus, the cleanliness of the interface between the laminated metal film 51 and the electrode film 52 can be improved. Adhesion and electron transport properties can be improved.

  Next, returning to FIG. 11, as shown in FIG. 11E, the buffer layer 210 is formed by a coating method (liquid phase method). The buffer layer material applied on the cathode 50 is adjusted to have a viscosity of 100 mPa · s or less, more preferably about 1 to 30 mPa · s, with an organic solvent. By adjusting the viscosity of the buffer layer material to a low viscosity, the material flows well so that the material enters the recesses on the surface of the cathode 50, so that the upper surface of the buffer layer 210 can be smoothly formed on a substantially flat surface. it can. Note that when the shrinkage-preventing fine particles are arranged in the buffer layer 210, the fine particles may be added to the buffer layer material in advance so as to have a predetermined content.

  The buffer layer material can be applied to a region covering the organic bank layer 221 by a slit die coating (or curtain coating) method. Moreover, you may apply | coat with an inkjet apparatus. When forming by the ink jet method, first, a buffer layer material is filled in the ink jet head (not shown), the discharge nozzle of the ink jet head is made to face the cathode 50, and the ink jet head and the base material (substrate 20) are relatively moved. Then, a predetermined amount of the buffer layer material can be applied onto the cathode 50 by discharging droplets with a controlled liquid amount per droplet from the discharge nozzle to the cathode 50.

Subsequently, a drying (curing) step of curing the buffer layer material applied on the cathode 50 is performed. As curing conditions, heating at 120 ° C. or lower or irradiation with light under atmospheric pressure or reduced pressure. Thereby, the organic solvent added in order to adjust the viscosity of the buffer layer material is volatilized and curing proceeds, and the buffer layer 210 is formed.
Thus, since the buffer layer 210 is cured by heating at a low temperature of 120 ° C. or lower or by light irradiation, the light emitting layer 60 is not heated above its heat resistant upper limit temperature. Therefore, the favorable light emitting layer 60 is obtained.

  Next, as shown in FIG. 11 (f), the gas barrier layer 30 is formed so as to cover the cathode 50 and the buffer layer 210, that is, to cover all portions of the cathode 50 exposed on the substrate 200. Here, as a method of forming the gas barrier layer 30, a silicon compound such as silicon oxynitride is formed by a high density plasma film forming method.

  The gas barrier layer 30 may be formed as a single layer with a silicon compound as described above, or may be laminated in a plurality of layers in combination with two or more layers of silicon compounds or materials different from silicon compounds. Although it may be formed by a single layer, the composition may be changed continuously or discontinuously in the film thickness direction.

Then, as shown in FIG. 12, a protective layer 204 including an adhesive layer 205 and a surface protective layer 206 is provided on the gas barrier layer 30. The adhesive layer 205 is applied substantially uniformly on the gas barrier layer 30 by a screen printing method, a slit die coating method, or the like, and the surface protective layer 206 is bonded thereon.
If the protective layer 204 is provided on the gas barrier layer 30 in this manner, the surface protective layer 206 has functions such as pressure resistance, wear resistance, antireflection, gas barrier property, and ultraviolet blocking property. The organic light emitting layer 60, the cathode 50, and also the gas barrier layer can be protected by the surface protective layer 206, and thus the life of the light emitting element can be extended.
In addition, since the adhesive layer 205 exhibits a buffering function against mechanical impact, when mechanical impact is applied from the outside, the mechanical impact on the gas barrier layer 30 and the light emitting element inside the gas barrier layer 30 is alleviated. It is possible to prevent functional deterioration of the light-emitting element due to mechanical impact.

  As described above, the EL display device 1 is manufactured. In such an EL display device 1, the thickness of each of the metal layers 61 and 62 is set using the vapor deposition devices 300, 400, and 500 shown in FIGS. Since the film is formed while being highly controlled, the laminated metal film 51 whose composition is controlled with high accuracy can be obtained over a long period of time with good reproducibility. As a result, electrons can be efficiently supplied from the electrode film 52 to the light emitting layer 60, and a light emitting element capable of emitting light with high luminance and high efficiency can be obtained. Therefore, it is bright and excellent in luminance uniformity. EL display device.

  In the above embodiment, an example in which the EL display device 1 is applied to an electro-optical device has been described. However, the present invention is not limited to this, and basically the electro-optical layer is interposed between an anode and a cathode. Any electro-optical device that is sandwiched can be used without any problem.

(Electronics)
Next, specific examples of an electronic device including the EL display device of the present invention will be described. An electronic apparatus according to the present invention has the above-described EL display device as a display unit, and specifically, the one shown in FIG.
FIG. 13 is a perspective view showing an example of a mobile phone. In FIG. 13, reference numeral 1300 indicates a mobile phone body, reference numeral 1301 indicates a display unit using the EL display device, 1302 indicates an operation button, 1303 indicates a receiver, and 1304 indicates a transmitter. This electronic device is provided with a display portion that can obtain a bright display and has low power consumption.

FIG. 1 is a diagram illustrating a wiring structure of an EL display device. FIG. 2 is a plan configuration diagram of the same. FIG. 3 is a cross-sectional configuration diagram taken along the line AB of FIG. 4 is a cross-sectional configuration diagram taken along line CD in FIG. 2. FIG. 5 is an enlarged cross-sectional view of a main part of FIG. 6 is an enlarged cross-sectional view of the main part of FIG. FIG. 7: is a cross-sectional block diagram (a) of a vapor deposition apparatus, and the plane block diagram (b) of the principal part. FIG. 8 is a cross-sectional configuration diagram (a) of the vapor deposition apparatus and a plan configuration diagram (b) of the main part. FIG. 9 is a cross-sectional configuration diagram of a vapor deposition apparatus. FIG. 10 is a cross-sectional process diagram of the EL display device. FIG. 11 is a cross-sectional process diagram of the EL display device. FIG. 12 is a sectional process diagram of an EL display device. FIG. 13 is a perspective configuration diagram illustrating an example of an electronic apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Display apparatus (electro-optical device), 23 ... Pixel electrode (anode), 30 ... Gas barrier layer, 50 ... Cathode, 51 ... Laminated metal film, 52 ... Electrode film, 60 ... Light emitting layer, 61 ... 1st metal layer, 62 ... second metal layer, 110 ... functional layer, 200 ... substrate, 204 ... protective layer, 210 ... buffer layer, 221 ... organic bank layer, 300,400,500 ... deposition apparatus, 310,510 ... deposition container, 311 , 501, 502 ... deposition chamber, 331, 332 ... deposition source, 334 ... boat, 341, 342 ... film forming material, 321, 322, 421 ... shutter (shielding means), 421 a ... opening, 350, 450, 550 ... Deposition control means

Claims (7)

An electro-optical device having an electro-optical layer sandwiched between an anode and a cathode,
The cathode is in contact with the electro-optic layer and injects electrons into the electro-optic layer, and is provided above the laminated metal film and is in contact with the laminated metal film and supplies the electrons to the laminated metal film. An electrode film
The laminated metal film includes a first metal layer that includes a low work function metal and contacts the electro-optic layer, and a second metal layer that includes a high work function metal having a higher work function than the low work function metal and contacts the electrode film And are stacked alternately,
The electrode film, only contains the high work function metal,
Of the constituent layers of the laminated metal film, a layer disposed at a position adjacent to the electro-optic layer is the first metal layer,
Of the constituent layers of the laminated metal film, the layer disposed on the surface layer opposite to the electro-optic layer is the second metal layer,
The low work function metal is one or more metals selected from the group consisting of magnesium, alkali metals, alkaline earth metals, and rare earth metals;
The high work function metal is one or more metals selected from the group consisting of conductive transition metals;
The electro-optical device , wherein the electro-optical layer includes an organic light emitting layer . 2. The electricity according to claim 1 , wherein the laminated metal film has a structure in which the first metal layer having a constant thickness and the second metal layer having a constant thickness are alternately laminated. Optical device. The ratio (d1 / d2) between the thickness d1 of the first metal layer and the thickness d2 of the second metal layer adjacent to each other is different at a plurality of portions in the thickness direction of the laminated metal film. The electro-optical device according to claim 1 . The film thickness ratio (d1 / d2) is relatively large on the electro-optic layer side and relatively small on the opposite side of the electro-optic layer in the film thickness direction of the laminated metal film. The electro-optical device according to claim 3 . On the opposite side of the laminated metal film from the electro-optic layer, an electrode film containing the high work function metal and having a film thickness larger than the first metal layer and the second metal layer constituting the laminated film is provided. The electro-optical device according to claim 1 , wherein the electro-optical device is provided. A method of manufacturing an electro-optical device having an electro-optical layer sandwiched between an anode and a cathode,
The step of forming the cathode includes a step of forming a laminated metal film in contact with the electro-optic layer and injecting electrons into the electro-optic layer, a layer provided on the laminated metal film and in contact with the laminated metal film and the Forming an electrode film for supplying the electrons to the laminated metal film,
The step of forming the laminated metal film includes a first metal layer including a low work function metal and in contact with the electro-optic layer, and a high work function metal having a higher work function than the low work function metal and in contact with the electrode film. Including alternately laminating second metal layers,
The step of forming the electrode film is to form the electrode film containing the high work function metal ,
The step of forming the laminated metal film includes a plurality of the first metal layer and the second metal while changing a film thickness ratio between the first metal layer and the second metal layer adjacent to the first metal layer. Including laminating layers,
In the step of forming the laminated metal film, the ratio (d1 / d2) between the film thickness d1 of the first metal layer and the film thickness d2 of the second metal layer adjacent to the first metal layer is It further includes laminating the first metal layer and the second metal layer so as to be relatively large on the electro-optic layer side in the film thickness direction of the metal film and relatively small on the opposite side to the electro-optic layer. A method of manufacturing an electro-optical device. An electronic apparatus comprising the electro-optical device according to claim 1 .

Images