JPH10158821A - Apparatus for production of organic el light emitting element and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an org. EL light emitting element formed by using a negative electrode capable of prolonging the life of the element by improving the adhesion property of a film at the boundary of the negative electrode and an apparatus for production of the org. EL light emitting element capable of forming the film of the negative electrode without limitation by the steam pressure, etc., the material and damaging the constituting film of the element and a method therefor. SOLUTION: This apparatus for producing the org. EL light emitting element is used for forming the film of the negative electrode or positive electrode of the org. EL element and has at least a substrate 1, a target 15 and a DC power source 7 for impressing a DC voltage between the substrate and the target. In such a case, an aperture 11 having an opening smaller than the target between a grid electrode which is grounding potential or positive potential and/or the target and the substrate is disposed between the target and the substrate. This process for producing the org. EL light emitting element consists in forming the film of the negative electrode by using the apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing an organic EL device using an organic compound (hereinafter, also referred to as an "organic EL device"). The present invention relates to a manufacturing apparatus and a method capable of forming a film.

[0002]

2. Description of the Related Art In recent years, organic EL devices have been actively studied. This is tin-doped indium oxide (ITO)
A hole transport material such as tetraphenyldiamine (TPD) is formed into a thin film on a transparent electrode (positive electrode) such as by vapor deposition, and a fluorescent substance such as an aluminum quinolinol complex (Alq ³ ) is laminated as a light emitting layer. Element having a basic structure in which a metal electrode (negative electrode) having a small work function is formed.
Attention has been paid to the extremely high luminance of cd / cm ² .

As a material used as a negative electrode of such an organic EL device, a material that injects a large amount of electrons into a light emitting layer is considered to be effective. In other words, it can be said that a material having a smaller work function is more suitable for the negative electrode. There are various materials having a low work function, and as a material used as a negative electrode of an EL light emitting element, for example, MgA described in JP-A-4-233194 is used.
g and AlLi are common. The reason for this is that organic E
Since the manufacturing process of the L light emitting element mainly performs vapor deposition using resistance heating, the vapor deposition source is naturally limited to those having a low temperature and a high vapor pressure. Further, since the evaporation process using such resistance heating is used, the adhesion at the film interface is deteriorated, and this has been a factor that determines the life of the element.

As one of the vacuum film forming methods, it is conceivable to use a normal sputtering method. However, in the case of the conventional sputtering method, an inert gas such as Ar is used, and a gas pressure of 0.5 to
Although the reaction is performed under the condition of 1.0 Pa, the sputtered atoms and atomic groups have a high kinetic energy of about several tens to several hundreds times as compared with the case of vapor deposition. Therefore, if a film is formed by sputtering directly on a light emitting layer or the like formed of an organic substance, damage is caused by electrons, and sufficient surface uniformity cannot be obtained. More specifically, a large number of ionized electrons collide with the organic EL element structure, damage the element constituent film, reduce the electrostatic breakdown voltage, and generate a leak when a voltage is applied between the positive and negative electrodes. As a result, it does not function as an element.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic EL light-emitting device using a cathode, which can improve the adhesion of a film at the interface of the cathode and extend the life of the device, and a vapor of a material. An object of the present invention is to provide an apparatus and a method for manufacturing an organic EL light-emitting element capable of forming the negative electrode without being limited by pressure or the like and damaging an organic constituent film of the element.

[0006]

This and other objects are achieved by the present invention which is defined below as (1) to (4). (1) DC for applying a DC voltage between at least a substrate, a target, and the substrate and the target, which is used for forming a negative electrode or a positive electrode of the organic EL element.
What is claimed is: 1. An apparatus for manufacturing an organic EL light emitting device, comprising: a DC sputtering apparatus having a power supply; and having a grid electrode at a ground potential or a positive potential between a target and a substrate. (2) The apparatus for manufacturing an organic EL device according to (1), wherein the DC sputtering apparatus has an aperture between the target and the substrate, the aperture having a smaller opening than the target. (3) The apparatus for manufacturing an organic EL light-emitting device according to (1) or (2), wherein the aperture is disposed closer to the target than the grid. (4) DC for applying a DC voltage between at least a substrate, a target, and the substrate and the target, which is used for forming a negative electrode or a positive electrode of the organic EL element.
An apparatus for manufacturing an organic EL light emitting element, comprising: a DC sputtering apparatus having a power supply, wherein an aperture having an opening smaller than the target is provided between the target and the substrate. (5) An organic EL device in which a negative electrode is formed on an organic EL device structure of an organic film mounted on a substrate by using the organic EL device manufacturing apparatus according to any one of (1) to (4). A method for manufacturing a light-emitting element.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a specific configuration of the present invention will be described in detail.

[0008] An apparatus for manufacturing an organic EL light emitting device according to the present invention comprises:
A DC sputtering apparatus having at least a substrate, a target, and a DC power supply for applying a DC voltage between the substrate and the target as a first sputtering apparatus, wherein a ground potential or a positive potential is provided between the target and the substrate. Which is a grid electrode. Alternatively, the second sputtering apparatus has an aperture of a ground potential having an opening smaller than the target between the target and the substrate.

By using a DC sputtering apparatus as the first sputtering apparatus, it becomes easy to control the kinetic energy of the sputtered atoms and atomic groups, the number of ions, and the like. By interposing a grid electrode of a ground potential or a positive potential between the target of the DC sputtering apparatus and the substrate, it is possible to prevent electrons derived from the ionized sputtering gas or the like from flying onto the substrate. Also, the kinetic energy of the sputtered atoms and atomic groups can be suppressed.

The second sputtering apparatus is a DC sputtering apparatus like the first sputtering apparatus. However, by providing a ground potential aperture having an opening having a smaller area than the target between the target and the substrate, the sputtering is performed. Ionization / ionization of gas occurs exclusively between the target and the aperture. Further, the sputtered atoms and atomic groups fly out of the opening of the aperture, accelerate and fly to the substrate. Therefore, the ionized electrons are present between the target and the aperture, and the number of flying electrons to the substrate is extremely small. More preferably, a third sputtering apparatus in which the first sputtering apparatus and the second sputtering apparatus are combined is used. This makes organic E more
L damage is reduced.

Next, the first to third sputtering apparatuses will be described in detail with reference to the drawings.

<First Sputtering Apparatus> FIG. 1 shows a structural example of an apparatus used for the first sputtering method.

The first sputtering apparatus is installed in a vacuum chamber (not shown), and a substrate 1, a conductor 2, and a grid on which a stacked structure of organic EL elements (hereinafter, sometimes referred to as an EL element stacked body) are mounted. 4, a target 5, a conductor 6, a first DC power supply 7, a conductor 8, and a second DC power supply 9.

The substrate 1 is grounded 3 by a conductor 2.
The target 5 is connected to the positive electrode of the first DC power supply 7 by a conductor 6, and the negative electrode of the first DC power supply 7 is grounded 3. That is, the sputter voltage supplied from the first DC power supply is applied between the substrate 1 and the target. Also, a grid 4 provided between the substrate targets
Is connected to the positive electrode of the second DC power supply 9 by a conductor 8, the negative electrode of the second DC power supply is grounded, and a bias voltage supplied from the second DC power supply is applied to the grid 4. .

The sputtering voltage supplied from the first DC power supply 7 accelerates the sputtering gas to sputter the target 5, and the atoms and atomic groups released from the target 5 are stacked on the EL element stack on the substrate 1. Adheres and deposits on top. At this time, the grid 4 between the target 5 and the substrate 1 is at a ground potential or a positive potential. Therefore, electrons generated by ionization of the sputtering gas are absorbed by the grid 4 and hardly reach the substrate 1. Further, the velocity (kinetic energy) of the emitted atoms and atomic groups is suppressed. Therefore, almost no electrons collide with the EL element stack, and
The velocity (kinetic energy) of the atomic group is also reduced, a negative electrode can be formed without damaging the light emitting layer, the electron transport layer, and the like, and the adhesion of the film is also improved.

The operating conditions of the first sputtering apparatus are as follows.
About 1 to 20 Pa is preferable. The sputtering voltage of the first DC power supply 7 is preferably 0.1 to 4 W / cm in terms of power.
² , especially 0.5-1 W / cm ² . Also, the second
The voltage of the DC power supply varies depending on the distance between the target and the grid, but is preferably 0 to 10 V, particularly 5 to 8 V.
A range of V is preferred.

Next, a specific dimensional relationship of such a first sputtering apparatus will be exemplified.

The substrate 1 preferably has a size of 10 to 50 cm square or diameter, the grid 4 preferably has a size larger than the substrate 1, and the target 5 has a size of 0.4 to 0.7 mm of the substrate 1.
Preferably, it has a double size. The distance between the substrate 1 and the target 5 is approximately 0.5 to 2 times the substrate size, particularly 5 to 20 cm.
The distance between the target 5 and the grid 4 is preferably 0.6 times or less the dimension between the substrate 1 and the target 5, and more preferably 0.1 to 0.5. And grid 4
-The dimension between the substrates 1 is preferably in the range of 1 to 5 cm. Also,
The mesh of grid 4 has a size of 1mm (hole) of 5mm
Those having a square or larger diameter and 30 mm square or smaller are preferred. <Second Sputtering Apparatus> FIG. 2 shows a configuration example of an apparatus used for the second sputtering method.

The second sputtering apparatus is installed in a vacuum chamber (not shown), and has a substrate 1, a conductor 2, an aperture 11, a target 5, a conductor 6, a first DC on which a laminated structure of organic EL elements is mounted. It comprises a power source 7 and a conductor 8.

The apertures 11 provided between the substrate targets are shown by cross-sectional end faces in this figure, and have a structure in which an opening is formed in the center of a disk or a square plate, or a slit shape. Is also good. The aperture 11 is grounded by a conductor 12. That is, the potential is the same as the negative side of the sputtering voltage supplied from the first DC power supply. Other configurations are the same as those of the first sputtering apparatus, and the same components are denoted by the same reference numerals and description thereof will be omitted.

The sputter voltage supplied from the first DC power supply 7 is applied exclusively between the target 5 and the aperture 11. For this reason, ionization and acceleration of the sputtering gas occur between the target 5 and the aperture 11, and the accelerated sputtering gas sputters the target 5, and atoms and atomic groups released from the target 5 pass through the opening of the aperture 11. It jumps out and adheres and deposits on the EL element laminate on the substrate 1. At this time, the electrons generated by the ionization of the sputtering gas and the like are exclusively generated in the target 5 and the aperture 1.
It will be between one. Therefore, target 5
-By making the distance between the substrates 1 sufficient, the generated electrons hardly reach the substrate 1. Also,
The velocity (kinetic energy) of the emitted atoms and atomic groups is suppressed. Therefore, almost no electrons collide with the EL element stack, the speed (kinetic energy) of atoms and atomic groups is reduced, and a negative electrode can be formed without damaging the light emitting layer, the electron transport layer, etc. The performance is also improved.

The operating conditions of the second sputtering apparatus are as follows.
About 1 to 20 Pa is preferable. The sputtering voltage of the first DC power supply 7 is preferably 0.1 to 4 W / cm in terms of power.
² , especially 0.5-1 W / cm ² .

Next, a specific dimensional relationship of such a second sputtering apparatus will be exemplified.

The substrate 1 is preferably in the range of about 40 to 50 cm square or diameter, and the diameter or side of the target 5 is preferably about 0.4 to 0.7 times the diameter or side of the substrate 1. Aperture 11
Has a size equal to or larger than the substrate 1. It is preferable that the opening is formed leaving 10 cm or less of the inner side. In particular, the opening diameter is about 8 cm, that is, the diameter or side of the aperture 11 is 0.2 to 0.2% of the substrate when the diameter or side of the target is 1.
A size of about 0.8 times is preferable. The distance between the substrate 1 and the target 5 is at least 1 time, particularly 1.2 to 5 times, particularly 20 cm or more, more preferably 20 to 40 cm of the substrate size. Between five. 1/5 to 5/6 times, especially 1/4 to
4/5 times, further preferably 0.6 times or less, especially 5 to 5 times
A range of 10 cm is preferred.

<Third Sputtering Apparatus> FIG. 3 shows a structural example of an apparatus used for the third sputtering method.

The third sputtering apparatus is installed in a vacuum chamber (not shown), and a substrate 1, a conductor 2, a grid electrode 4, an aperture 11, a target 5, a conductor 6, It comprises a first DC power supply 7, a second DC power supply 9, and a conductor 8.

That is, the third sputtering apparatus has both the grid electrode 4 and the aperture 11 and has less damage to the organic EL element.
Is more preferable than the above sputtering apparatus. Although it is possible to bring the grid 4 and the aperture 11 closer to a position where they do not come into contact with each other, the grid is preferably located at a distance of at least 5 mm from the substrate 1 and usually at a distance of 5 to 10 mm. At this time, when the grid is arranged closer to the substrate than the aperture as shown in FIG. 3, damage to the element is further reduced. Other operations and dimensional relationships are based on the first and second sputtering apparatuses. In addition, the same components are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 4 shows a third modification. In this example, the grid 4 is located at the same position or a position on the lower surface side thereof in a range where the grid 4 does not contact the aperture 11. In this case, the size of the grid 4 may be equal to (or slightly larger than) the opening size of the aperture 11. The other configuration is the same as that of the apparatus shown in FIG. 3, and the description is omitted. In this case, damage to the element is reduced as compared with the case where the grid and the aperture are used alone.

In each of the first to third sputtering apparatuses, substantially the same negative electrode can be obtained and used as an electron injection electrode. That is, damage to the organic EL element structure is reduced. In addition, it can be used for forming a positive electrode of an organic EL element.

As a constituent material of the negative electrode formed by the first to third sputtering devices, a material having a low work function, for example, as a material having a low work function in order to effectively perform electron injection.
K, Li, Na, Mg, La, Ce, Ca, Sr, B
a, a metal element such as Al, Ag, In, Sn, Zn, Zr, etc., or a metal element containing them in order to improve stability.
It is preferable to use a three-component alloy system. As an alloy system, for example, Ag.Mg (Ag: 1 to 20 at%),
Al.Li (Li: 0.5 to 10 at%), In.Mg
(Mg: 50-80 at%), Al.Ca (Ca: 5-2)
0 at%) and the like. Therefore, such a metal or alloy constituting the negative electrode is usually used as a target.

The thickness of the negative electrode thin film may be a certain thickness or more for sufficiently injecting electrons, and may be 50 nm or more, preferably 100 nm or more. Although the upper limit is not particularly limited, the film thickness may be usually about 100 to 500 nm.

The organic light-emitting device manufactured by the method of the present invention has a positive electrode on a substrate and a negative electrode on the positive electrode, and is sandwiched between these electrodes to form at least one charge transport layer and at least one charge transport layer. It has a light emitting layer, and further has a protective layer as an uppermost layer. Note that the charge transport layer can be omitted. As described above, the negative electrode is made of a metal or an alloy having a small work function and formed by the first or second sputtering apparatus.

A transparent electrode (positive electrode) such as zinc-doped indium oxide (IZO) is provided on a glass substrate by a sputtering method, and a hole transport material such as tetraphenyldiamine (TPD) is formed on the transparent electrode by evaporation or the like to form a thin film. Further, a fluorescent substance such as an aluminum quinolinol complex (Alq ³ ) is laminated as a light emitting layer. These organic EL elements before forming the negative electrode are referred to as an organic EL element structure. The light emitting element in which the above-described negative electrode having a low work function is laminated by the first or second sputtering apparatus and finally a SiO ₂ film or the like is formed as a protective film by a sputtering method is a light emitting layer or an electron injection layer. The adhesion at the negative electrode thin film interface is improved without damaging the transport layer and the like, and extremely stable light emission quality can be obtained.

FIG. 5 shows an example of the structure of an organic EL device manufactured according to the present invention. The EL device shown in FIG. 1 has a positive electrode 22, a hole injection / transport layer 23, a light emission and electron injection / transport layer 24, and a negative electrode 25 in this order on a substrate 21.

The EL device of the present invention is not limited to the illustrated example, but may be of various configurations. For example, a light emitting layer is provided alone, and an electron injection / transport layer is interposed between the light emitting layer and the metal electrode. It is also possible to adopt a configuration. If necessary, the hole injection / transport layer 23 and the light emitting layer may be mixed.

The negative electrode can be formed as described above, the organic layer such as the light-emitting layer can be formed by vacuum deposition, and the positive electrode can be formed by vapor deposition or sputtering. Depending on the conditions, patterning can be performed by a method such as etching after mask evaporation or film formation, whereby a desired light emitting pattern can be obtained. Further, the substrate is a thin film transistor (TFT), and by forming each film according to the pattern, a display and drive pattern can be used as it is. Finally, the SiO
_A protective layer made of an inorganic material such as _X or an organic material such as Teflon may be formed.

The protective layer may be transparent or opaque in a configuration in which light emitted from the substrate is extracted. To make it transparent, use a transparent material (eg, SiO ₂ , SIALON).
Etc.) may be selected or used, or the thickness may be controlled so as to be transparent (preferably, the transmittance of emitted light is 80% or more). Generally, the thickness of the protective layer is 50-1200.
It is about nm. The protective layer may be formed by a general sputtering method, a vapor deposition method, or the like.

Further, it is preferable to form a sealing layer on the device in order to prevent oxidation of the organic layers and electrodes of the device. The sealing layer is made of an adhesive resin layer such as a commercially available low-moisture-absorbing light-curing adhesive, an epoxy-based adhesive, a silicone-based adhesive, and a cross-linked ethylene-vinyl acetate copolymer adhesive sheet to prevent moisture from entering. Is used to adhere and seal a sealing plate such as a glass plate. Besides a glass plate, a metal plate, a plastic plate or the like can be used.

Next, the organic layer provided in the EL device of the present invention will be described.

The light emitting layer has a function of injecting holes (holes) and electrons, a function of transporting them, and a function of generating excitons by recombination of holes and electrons. It is preferable to use a relatively electronically neutral compound for the light emitting layer.

The charge transport layer has a function of facilitating injection of holes from the positive electrode, a function of transporting holes, and a function of blocking electrons, and is also called a hole injection transport layer.

In addition, if necessary, for example, when the electron injecting / transporting function of the compound used in the light emitting layer is not so high, injection of electrons from the negative electrode between the light emitting layer and the negative electrode as described above. May be provided with an electron injecting and transporting layer having a function of facilitating electron transport, a function of transporting electrons, and a function of blocking holes.

The hole injection transport layer and the electron injection transport layer are
Increases and confines holes and electrons injected into the light emitting layer,
Optimize the recombination region and improve luminous efficiency.

The hole injecting / transporting layer and the electron injecting / transporting layer may be separately provided in a layer having an injection function and a layer having a transport function.

The thickness of the light emitting layer, the thickness of the hole injecting and transporting layer, and the thickness of the electron injecting and transporting layer are not particularly limited, and vary depending on the forming method.
It is preferable to set it to 100 nm.

The thickness of the hole injecting / transporting layer and the thickness of the electron injecting / transporting layer depend on the design of the recombination / light emitting region, but may be about the same as the thickness of the light emitting layer or about 1/10 to 10 times. . When the injection layer and the transport layer for electrons or holes are separated from each other, it is preferable that the injection layer has a thickness of 1 nm or more and the transport layer has a thickness of 20 nm or more. At this time, the upper limit of the thickness of the injection layer and the transport layer is usually about 100 nm for the injection layer and 100 nm for the transport layer.
It is about nm. Such a film thickness is the same when two injection / transport layers are provided.

Further, by controlling the film thickness in consideration of the carrier mobility and carrier density (determined by ionization potential and electron affinity) of the combined light emitting layer, electron injection transport layer and hole injection transport layer, recombination is achieved. It is possible to freely design the region and the light emitting region, and it is possible to design the light emission color, control the light emission luminance and light emission spectrum by the interference effect of both electrodes, and control the spatial distribution of light emission.

The light emitting layer of the EL device of the present invention contains a fluorescent substance which is a compound having a light emitting function. Examples of the fluorescent substance include metal complex dyes such as tris (8-quinolinolato) aluminum disclosed in JP-A-63-264692. In addition, or in addition, or alone, quinacridone, coumarin, rubrene, styryl dye, other tetraphenylbutadiene, anthracene, perylene, coronene,
A 2-phthaloperinone derivative or the like can also be used. The light emitting layer may also serve as the electron injection / transport layer. In such a case, it is preferable to use tris (8-quinolinolato) aluminum or the like. These fluorescent substances may be deposited or the like.

The electron injecting and transporting layer, which is provided as necessary, includes an organic metal complex such as tris (8-quinolinolato) aluminum, an oxadiazole derivative, a perylene derivative, a pyridine derivative, a pyrimidine derivative, a quinoline derivative, and a quinoxaline derivative. , A diphenylquinone derivative,
Nitro-substituted fluorene derivatives and the like can be used.
As described above, the electron injection / transport layer may also serve as the light emitting layer. In such a case, it is preferable to use tris (8-quinolinolato) aluminum or the like. The formation of the electron injecting and transporting layer may be performed by vapor deposition or the like, similarly to the light emitting layer.

When the electron injecting and transporting layer is formed separately in the electron injecting layer and the electron transporting layer, a preferable combination can be selected from the compounds for the electron injecting and transporting layer. At this time, it is preferable to stack the layers of the compound having the higher electron affinity from the cathode side. This stacking order is the same when two or more electron injection / transport layers are provided.

The hole injecting and transporting layer is described in, for example, JP-A-63-295695 and JP-A-2-191694.
JP, JP-A-3-792, JP-A-5-2346
No. 81, JP-A-5-239455, JP-A-5
JP-A-299174, JP-A-7-126225, JP-A-7-126226, JP-A-8-100
Various organic compounds described in JP-A-172, EP0650955A1, and the like can be used. For example, a tetraarylbendicine compound (tetraaryldiamine to tetraphenyldiamine: TPD), an aromatic tertiary amine, a hydrazone derivative, a carbazole derivative, a triazole derivative, an imidazole derivative, an oxadiazole derivative having an amino group, polythiophene, and the like. . Two or more of these compounds may be used in combination, and when they are used in combination, they may be stacked as separate layers or mixed.

When the hole injecting and transporting layer is provided separately as a hole injecting and transporting layer, a preferable combination can be selected from the compounds for the hole injecting and transporting layer. At this time, it is preferable to stack the layers of the compound having the smaller ionization potential in order from the positive electrode (ITO or the like) side. It is preferable to use a compound having a good thin film property on the surface of the positive electrode. Such a stacking order is the same when two or more hole injection / transport layers are provided. With such a stacking order, the driving voltage is reduced, and the occurrence of current leakage and the occurrence and growth of dark spots can be prevented. In the case of forming an element, a thin film of about 1 to 10 nm can be made uniform and pinhole-free because of the use of vapor deposition, so that the hole injection layer has a small ionization potential and has absorption in the visible part. Even when such a compound is used, it is possible to prevent a change in the color tone of the emission color or a decrease in efficiency due to reabsorption.

The hole injection transport layer may be formed by depositing the above compound in the same manner as in the light emitting layer and the like.

In the present invention, the material and thickness of the transparent electrode used as the positive electrode are preferably determined so that the transmittance of emitted light is preferably 80% or more. Specifically, for example, tin-doped indium oxide (ITO), zinc-doped indium oxide (IZ)
O), SnO _2, it is preferable to use doped polypyrrole and a dopant into the positive electrode. The thickness of the positive electrode is preferably about 10 to 500 nm. Further, it is necessary that the driving voltage be low in order to improve the reliability of the element.

In the case of a structure in which light emitted from the substrate side is taken out, a transparent or translucent material such as glass, quartz, or resin is used as the substrate material. Further, the emission color may be controlled by using a color filter film, a color conversion film containing a fluorescent substance, or a dielectric reflection film on the substrate.

The organic EL device of the present invention is usually used as a DC drive type EL device, but it can be AC drive or pulse drive. The applied voltage is usually 2 to 2
It is about 0V.

[0057]

EXAMPLES Hereinafter, the present invention will be described in more detail by showing specific examples of the present invention.

<Example 1> ITO was patterned on a 127 mm square glass substrate as a transparent electrode to a thickness of 200 nm by a sputtering method, ultrasonically washed with a neutral detergent, acetone and ethanol, and then heated in boiling ethanol. And dried. After the surface of this transparent electrode was washed with UV / O _3, it was fixed to a substrate holder of a vacuum evaporation apparatus, and the inside of the bath was kept
The pressure was reduced to ^10-4 Pa or less.

Next, N, N'-
Diphenyl-N, N'-m-tolyl-4,4'-diamino-1,1'-biphenyl (TPD) was deposited at a deposition rate of 0.2.
Vapor deposition was performed at a thickness of 55 nm at a rate of nm / sec to form a hole injection transport layer.

Further, while maintaining the reduced pressure, Alq ³ : tris (8-quinolinolato) aluminum is evaporated at a vapor deposition rate of 0.1%.
Evaporation was performed at a thickness of 50 nm at 2 nm / sec to form an electron injection / transport / light-emitting layer.

Next, the film was transferred from the vacuum evaporation apparatus to the first sputtering apparatus, and the Ag / Mg alloy (M
g: 5 at%) as the target and the negative electrode at a rate of 15
A film was formed at a thickness of 200 nm at a rate of nm / min. At this time, Ar was used as the sputtering gas, and the gas pressure was 0.5 Pa. The input power was 500 W and the grid voltage was 6 V. The size of the target is 4 inches in diameter, the distance between the substrate and the target of the sputtering apparatus is 15 cm, the distance between the target and the grid is 5 cm, and the mesh (hole) of the grid
Was 15 mm square. The uniformity of the surface of the obtained negative electrode thin film was confirmed by a scanning electron microscope.
Met.

Finally, an organic thin film light emitting device (EL device) was obtained by sputtering SiO ₂ to a thickness of 200 nm as a protective layer.

A direct current voltage was applied to this organic thin-film light emitting device in an N ₂ atmosphere, and the device was continuously driven at a constant current density of 10 mA / cm ² . Initially, green light emission (maximum emission wavelength λmax = 520 nm) of 9 V and 200 cd / cm ² was confirmed. The half-life of luminance is 500 hours, during which the driving voltage rises by 2 hours.
V. During this time, generation and growth of dark spots were not confirmed.

<Example 2> An organic EL device was obtained in the same manner as in Example 1 except that the negative electrode was formed as follows.

Transfer from the vacuum evaporation apparatus to the second sputtering apparatus, and use a DC sputtering method to make an Ag.Mg alloy (Mg: 5 at
%) As a target, a negative electrode was formed to a thickness of 200 nm at a rate of 8 nm / min. At this time, Ar was used as a sputtering gas, the gas pressure was 0.3 Pa, and the input power was 1 K
W. The distance between the substrate and the target in the sputtering apparatus was 40 cm, and the distance between the target and the aperture was 6 cm.
cm, the size of the substrate was 40 cm in diameter, the size of the target was 4 inches in diameter, the size of the aperture was 15 cm, and the opening was 8 cm in diameter. The uniformity of the surface of the obtained negative electrode thin film was confirmed by a scanning electron microscope and found to be 100 nm ± 20%.

Finally, SiO ₂ was sputtered to a thickness of 200 nm to obtain an organic thin film light emitting device (EL device) as a protective layer.

A DC voltage was applied to this organic thin-film light emitting device in an N ₂ atmosphere, and the device was continuously driven at a constant current density of 10 mA / cm ² . Initially, green light (maximum emission wavelength λmax = 520 nm) of 8 V and 250 cd / cm ² was confirmed. The half-life of luminance is 500 hours, during which the drive voltage rises by 1
V. During this time, generation and growth of dark spots were not confirmed.

<Example 3> An organic EL device was obtained in the same manner as in Example 1 except that the negative electrode was formed as follows.

The vacuum evaporation apparatus was transferred to a third sputtering apparatus having the structure shown in FIG. 3, and a negative electrode was formed at a rate of 8 nm / min and a thickness of 200 nm by a DC sputtering method using an Ag.Mg alloy (Mg: 5 at%) as a target. Then, a film was formed. At this time, Ar was used as the sputtering gas, the gas pressure was 0.3 Pa, and the input power was 1 kW. The substrate of the sputtering apparatus
The distance between the targets was 40 cm, the distance between the target and the aperture was 6 cm, the size of the substrate was 40 cm in diameter, the size of the aperture was 15 cm in diameter, and the opening was 8 cm in diameter. Also,
The grid voltage was 6 V, the size of the target was 4 inches in diameter, the distance between the target and the grid was 5 cm, and the mesh (hole) of the grid was 15 mm square. The uniformity of the surface of the obtained negative electrode thin film was confirmed by a scanning electron microscope.
00 nm ± 20%.

Finally, SiO ₂ was sputtered to a thickness of 200 nm to obtain an organic thin film light emitting device (EL device) as a protective layer.

A direct current voltage was applied to this organic thin film light emitting device in an N ₂ atmosphere, and the device was continuously driven at a constant current density of 10 mA / cm ² . Initially, green emission (maximum emission wavelength λ max = 520 nm) of 8.5 V and 250 cd / cm ² was confirmed. The half-life of luminance was 1000 hours, during which the drive voltage rose by 2V. During this time, generation and growth of dark spots were not confirmed.

[0072]

According to the present invention, it is possible to provide a negative electrode for an organic light-emitting device capable of improving the adhesion of a film at the negative electrode interface and extending the life of the device. Further, the negative electrode can be provided without being limited by the vapor pressure of the material.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a basic configuration of a first sputtering apparatus of the present invention.

FIG. 2 is a conceptual diagram showing a basic configuration of a second sputtering apparatus of the present invention.

FIG. 3 is a conceptual diagram showing a basic configuration of a third sputtering apparatus of the present invention.

FIG. 4 is a conceptual diagram showing another example of the third sputtering apparatus of the present invention.

FIG. 5 is a conceptual diagram showing a configuration example of an organic EL light emitting device manufactured according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Conductor 3 Ground 4 Grid 5 Target 6 Conductor 7 First DC power supply 8 Conductor 9 Second DC power supply 11 Aperture 21 Substrate 22 Positive electrode 23 Hole injection / transport layer 24 Light emitting / electron injection / transport layer 25 Negative electrode

Claims (5)

[Claims] 1. A DC sputtering apparatus for forming a negative electrode or a positive electrode of an organic EL device, comprising at least a substrate, a target, and a DC power supply for applying a DC voltage between the substrate and the target. What is claimed is: 1. An apparatus for manufacturing an organic EL element, comprising: a grid electrode at a ground potential or a positive potential between a target and a substrate. 2. The apparatus according to claim 1, wherein said DC sputtering apparatus has an aperture having a smaller opening than said target between said target and said substrate. 3. The organic electroluminescent device according to claim 1, wherein said aperture is arranged on a target side of said grid.
An apparatus for manufacturing an L light emitting element. 4. A DC sputtering system for forming a negative electrode or a positive electrode of an organic EL device, the DC sputtering device comprising at least a substrate, a target, and a DC power supply for applying a DC voltage between the substrate and the target. What is claimed is: 1. An apparatus for manufacturing an organic EL device, comprising: an aperture having an opening smaller than a target between a target and a substrate. 5. An organic EL light-emitting device, wherein a negative electrode is formed on an organic EL device structure of an organic film mounted on a substrate by using the organic EL device manufacturing apparatus according to claim 1. Device manufacturing method.