JP2005142079A - Sputtering device, sputtering method, manufacturing device of organic electroluminescence element, and manufacturing method of organic electroluminescence element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sputtering device for forming a transparent electrode of an upper part in a sputtering method by minimizing damages to the organic EL layer which is apt to degrade, and to prevent a film-forming method, a manufacturing device of the organic EL element using this device, and a manufacturing method of the organic EL element. <P>SOLUTION: The sputtering device for making the transparent electrode for a top emission type organic EL element, containing at least an electrode, a target, a substrate, and a substrate holder holding the substrate, is provided with a means for keeping hazardous substance off the substrate. The above means includes one or a plurality of means selected from among (a) a means of impressing bias on the substrate, (b) a means of impressing bias on a shielding plate fitted between the substrate and the electrode, and (c) a means of impressing a magnetic field between the substrate and the electrode, in parallel with the substrate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an organic EL light emitting device, and more particularly to a method and apparatus for manufacturing an organic EL light emitting device.

  In 1987, Eastman Kodak's C.I. W. Since Tang announced a highly efficient organic EL light-emitting device as a device having a two-layer structure by Tang, various organic EL light-emitting devices have been developed and partially put into practical use (Non-patent Document 1). Under such circumstances, development of a full-color organic EL light-emitting element panel is urgently developed as a next-generation organic EL light-emitting element panel.

  In the bottom emission type organic EL light emitting element, there are three methods of coloring, such as a three-color painting method, a color conversion method (hereinafter referred to as CCM method), and a color filter method (Non-Patent Document 2). Among these methods, the CCM method and the color filter method do not require the use of a metal mask at the time of film formation, and the color conversion layer and the color filter may be formed on the substrate by a photo process. Is advantageous.

  However, it is generally difficult to produce an active matrix drive display by the color conversion method or the color filter method. The reason is that a color conversion layer and a filter layer exist between the TFT substrate and the organic EL layer, and it is necessary to make a contact hole in order to connect the organic EL layer and the TFT. The color conversion layer and the color filter are organic substances and contain a lot of moisture because they are patterned by a photo process. The color panels of the color conversion method and the color filter method are protected by a passivation film so that these moisture do not enter the organic EL layer. However, in order to make a contact hole for connecting the TFT and the organic EL layer, it is necessary to make a hole in the passivation layer, and a passivation effect cannot be expected.

  A solution to such a problem is to realize full color with a top emission type in which light is extracted to the side opposite to the support substrate (Non-patent Document 2). Specifically, a top emission type organic EL light emitting device is manufactured on a TFT substrate, and a color conversion substrate or a color filter substrate is bonded thereon to manufacture a color display. The step of bonding the top emission type organic EL light emitting element and the substrate can avoid the above-mentioned problem of contact holes, and can be simplified in terms of the process to improve the mass productivity.

  On the other hand, in the three-color coating method, the organic EL layer can be directly formed on the TFT substrate, and therefore it is easy to manufacture an active matrix driving panel. However, in order to suppress the variation of the organic EL layer and the variation of the TFT and operate the active matrix drive stably, a large number of TFTs are required for one pixel. Since light cannot be transmitted over the TFT, when the number of TFTs increases, the so-called bottom emission type organic EL light emitting element has a small aperture ratio. Therefore, although it is a reason different from the color conversion method and the color filter method, it is desired to develop a top emission type organic EL light emitting element that extracts light to the side opposite to the support substrate.

  The top emission type organic EL light emitting device has a structure in which, for example, a reflective electrode is formed on a support substrate, an organic EL layer is formed thereon, and finally a transparent electrode is laminated. Therefore, the light emitted from the organic light emitting layer is extracted in the direction opposite to the support substrate. Generally, a transparent semiconductor oxide such as ITO, IZO or ZnO is used for the transparent electrode. In order to laminate these layers, it is desirable to produce them by a sputtering method which is excellent in terms of mass productivity and characteristics. However, when a transparent electrode is laminated on the organic EL layer using a sputtering method, the organic EL layer is damaged. This damage to the organic EL layer becomes a serious problem in operation such as degradation of the efficiency of the element and voltage increase.

C. W. Tang, S.M. A. VanSlyke, Appl. Phys. Lett. 51, 913 (1987) Kenya Sakurai, “Technology Development Status and Prospects of Full-Color Organic EL by Color Conversion Method,” October Monthly Display, page 59 (2002)

  Therefore, the present invention provides a sputtering apparatus for forming an upper (transparent) electrode by a sputtering method, a film forming method, and organic EL light emission using the apparatus while minimizing damage to a layer that is easily deteriorated such as an organic layer. An element manufacturing apparatus and an organic EL light emitting element manufacturing method are provided.

  A sputtering apparatus according to a first embodiment of the present invention is a sputtering apparatus for producing a transparent electrode of a top emission type organic EL light-emitting element including at least an electrode, a target, a substrate, and a substrate holder for holding the substrate in a vacuum chamber. The apparatus has means for preventing harmful substances from coming close to the substrate. The means includes: a) means for applying a bias to the substrate holder; b) providing a shielding plate between the substrate and the electrode, and applying a bias to the shielding plate. A sputtering apparatus comprising: means for applying; and c) one or more means selected from means for applying a magnetic field in parallel with the substrate between the substrate and the electrode.

  The sputtering method according to the second embodiment of the present invention uses a sputtering apparatus for producing a transparent electrode of a top emission type organic EL light emitting device including at least an electrode, a target, a substrate, and a substrate holder for holding the substrate in a vacuum chamber. Forming a film on the substrate, a) applying a bias to the substrate holder, b) providing a shielding plate between the substrate and the electrode, and applying a bias to the shielding plate, and c And a method comprising preventing a harmful substance or substances selected from applying a magnetic field between the substrate and the electrode in parallel with the substrate from coming into contact with the substrate.

  An apparatus for producing a top emission type organic EL light emitting device according to a third embodiment of the present invention is a device for producing a top emission type organic EL light emitting element including at least an organic vapor deposition chamber and a sputtering apparatus for producing a transparent electrode. The transparent electrode manufacturing sputtering apparatus has means for preventing harmful substances from being brought close to the substrate, the means a) means for applying a bias to the substrate holder, and b) a shielding plate is provided between the substrate and the electrode. And a means for applying a bias to the shielding plate, and c) one or a plurality of means selected from means for applying a magnetic field parallel to the substrate between the substrate and the electrode. is there.

  The manufacturing method of the top emission type organic EL light emitting device according to the fourth embodiment of the present invention includes a step of laminating at least a reflective electrode on a support substrate, a step of laminating an organic EL layer, and a step of laminating a transparent electrode. In the method of manufacturing a top emission type organic EL light-emitting device including: a step of laminating the transparent electrode using a sputtering apparatus including at least an electrode, a target, a substrate, and a substrate holder for holding the substrate in a vacuum chamber; A step of forming a film on the substrate, during which a) applying a bias to the substrate holder, b) providing a shielding plate between the substrate and the electrode, and applying a bias to the shielding plate And c) while applying a method of preventing one or more harmful substances selected from applying a magnetic field between the substrate and the electrode in parallel with the substrate from coming into contact with the substrate Is a manufacturing method characterized by film.

  By using the apparatus or method of the present invention, when the transparent electrode of the top emission type organic EL light emitting element is laminated by sputtering, the collision of oxygen ions to the substrate laminated up to the organic EL layer is reduced, and the organic EL Damage to the layer can be minimized. In addition, it is possible to manufacture an organic EL light emitting element having characteristics equivalent to those of the bottom emission type.

  The present invention relates to a method and a sputtering apparatus for minimizing damage to a substrate when a target is stacked on the substrate by sputtering.

  Possible harmful substances that damage the substrate surface by sputtering are (1) oxygen ions that are knocked out of the gas or from the target and collide with the surface to be laminated, and (2) during sputtering that collide with the surface to be laminated. (3) the influence of ultraviolet rays generated from the plasma, (4) sputtered target particles that collide with the surface to be laminated, and (5) oxygen radicals. Also, (6) temperature rise during sputtering causes damage due to sputtering.

  FIG. 1 shows the characteristics of an organic EL light emitting device when Al is deposited as a cathode after irradiating an organic EL layer before producing a transparent electrode with Ar plasma and oxygen plasma. As shown in FIG. 1, the deterioration of the luminance of the organic EL light emitting element is more remarkable in the case of irradiation with oxygen ions than in the case of irradiation with Ar ions. From this, it can be expected that oxygen ions greatly affect the deterioration of the organic EL layer.

  Furthermore, when producing a transparent electrode, the element does not collide with a method in which particles directly sputtered using facing sputtering or the like do not collide with the substrate, or when the kinetic energy of sputtered particles is reduced by increasing the sputtering gas pressure. It has been confirmed by experiments that it deteriorates. Therefore, it is not enough to alleviate the damage to the organic EL layer only by mitigating the collision of the high-energy particles reaching the substrate.

  As described above, since the collision of oxygen ions with the substrate during sputtering has a significant effect on the organic EL layer, the present invention reaches the substrate with oxygen ions, which are harmful substances that are damaging to the organic EL layer. We propose a technique for depositing a transparent electrode on the organic EL layer without causing the problem to occur.

  Below, when laminating a transparent electrode on a substrate from a sputtering device for laminating a transparent electrode on a substrate where at least a reflective electrode and an organic layer are laminated on a support substrate, oxygen ions that are harmful substances are brought close to the substrate. The structure of the sputtering apparatus of the present invention for forming a film so as not to occur will be described in detail.

  Three specific embodiments of the sputtering apparatus of the present invention are shown in FIGS. 2 to 4 are connected to a DC sputtering power source 16 and an RF sputtering power source 25, and a pair of electrodes 17 to which DC and RF can be applied simultaneously, and a target 18 installed on the cathode of the electrode 17. The substrate holder 19 and the substrate 21 installed on the substrate holder 19 are common. Moreover, although each embodiment is not shown in figure, these apparatuses are surrounded by the vacuum chamber provided with the vacuum pump. When a voltage is applied across the electrodes 17 and exhausted by a vacuum pump, glow discharge occurs at a certain degree of vacuum, cations are accelerated by the electric field, collide with the cathode, and kinetic energy strikes the target at the cathode. . The target that is struck out and sticks out adheres to the substrate and forms a film. In this case, not only the target but also oxygen ions that are generated from the material or exist as a gas collide with the substrate. This collision of oxygen ions damages the organic EL layer before forming the transparent electrode when the transparent electrode of the top emission type organic EL light emitting element is laminated by sputtering. An apparatus for avoiding this is the embodiment shown in FIGS.

  The embodiment shown in FIG. 2 is characterized in that a bias power source 20 is connected to the substrate holder 19. A negative bias can be applied to the substrate holder 19 by the bias power source 20 connected to the substrate holder 19. Therefore, the substrate holder needs to be conductive, and specifically, a SUS (Steel Use Stainless) or an aluminum plate adhered with a conductive metal by plating or the like can be considered. SUS is preferred. When a negative bias is applied to the substrate holder 19 by the bias power source 20, negative ions such as oxygen ions that collide with the surface of the substrate together with the target material at the time of sputtering reach the substrate 21 installed on the substrate holder 19. I can't do that. Thereby, the damage which the surface of the board | substrate 21 receives by collision of oxygen ion can be suppressed. Although FIG. 2 applies a negative bias to the substrate holder 19, it is also possible to apply a negative bias directly to the substrate 21. However, when used for manufacturing an organic EL light emitting device, the film may be deposited on an insulating support substrate (glass or plastic) and the substrate may not be biased directly. Thus, it is effective to apply a bias to the substrate holder 19.

  The embodiment shown in FIG. 3 is characterized in that a shielding plate 22 is installed between the substrate 21 and the electrode 17 in parallel with the substrate 21. A bias can be applied by connecting a bias power source to the shielding plate 22 installed between the substrate 21 and the electrode 17. In this way, during sputtering, negative ions such as oxygen ions that collide with the substrate surface together with the target material do not pass through the negatively biased shielding plate 22 and the oxygen ions collide with the substrate surface. This can prevent the substrate surface from being damaged by the collision of oxygen ions. The shielding plate 22 used in the embodiment shown in FIG. 3 is a conductive plate having a hole, and specifically, a SUS or aluminum plate having a conductive metal attached thereto by plating or the like can be considered. . SUS is preferred. The shielding plate is larger than the substrate holder and has one or more holes having a diameter of 0.1 mm to 10 mm, preferably 0.1 mm to 2 mm. The number of holes is such that the target particles can reach the substrate 21 through the holes and can be stacked, and is appropriately changed according to the area of the shielding plate. The hole opened in the shielding plate can penetrate neutral particles, but cannot pass negative ions such as oxygen ions. This shielding plate is disposed between the electrode 17 and the substrate 21 at a position 0.5 cm to 20 cm, preferably 1 cm to 10 cm from the substrate 21 in parallel with the substrate 21.

  The embodiment shown in FIG. 4 is characterized in that a pair of magnets 23 is installed between the substrate 21 and the electrode 17. A magnetic field 24 can be generated between the substrate 21 and the electrode 17 by a pair of magnets 23 disposed between the substrate 21 and the electrode 17. As shown in FIG. 4, the magnetic field 24 is applied between the electrode 17 and the substrate 21 at a position 0.5 cm to 20 cm, preferably 1 cm to 10 cm from the substrate 21 in parallel with the substrate 21. The path of oxygen ions that collide with the surface of the substrate together with the target material can be bent to prevent collision of oxygen ions with the substrate surface, and damage to the substrate surface due to collision of oxygen ions can be suppressed.

  Furthermore, these apparatuses are not limited to a normal parallel plate sputtering apparatus, but can be applied to an opposing sputtering or the like in which a substrate is installed off-axis.

  Each embodiment may be combined. That is, the means for applying a bias to the substrate holder, the substrate or the shielding plate and the means for applying a magnetic force parallel to the substrate are not limited to being installed alone, and may be installed at the same time.

  Next, when the transparent electrode is laminated on the substrate from the sputtering device for laminating the transparent electrode on the support substrate, at least on the substrate on which the reflective electrode and the organic layer are laminated, A method for keeping negative ions such as oxygen ions, which are harmful substances, away from the substrate will be described in detail with reference to FIGS.

First, common operations in the methods of FIGS. A substrate 21 to be deposited is set on the substrate holder 19, and a target is set on the cathode side of the electrode 17. A gas such as Kr, Xe, preferably Ar or Ar + O ₂ is introduced into the sputtering apparatus. When Ar + O ₂ is used, for example, a mixed gas of Ar: O ₂ = 9: 1 can be used. The substrate temperature during sputtering is set to room temperature to 100 ° C., preferably room temperature. These conditions are only general conditions, and actually vary depending on the target material or apparatus to be used. Therefore, the conditions are changed as appropriate. Next, a voltage of 1 W to 5 kW, preferably 10 W to 1000 W is applied between the electrodes 17 by the DC sputtering power source 16 and / or the RF sputtering power source 25, and the inside of the sputtering apparatus is 0.01 Pa to 10 Pa by a vacuum pump. Preferably, it is set to 0.05 Pa to 2 Pa. Then, glow discharge occurs, positive ions are accelerated by the electric field, collide with the cathode, and kinetic energy strikes the target at the cathode. The target that is struck out and sticks out adheres to the substrate and forms a film. In this case, not only the target but also oxygen ions generated from the material or generated from oxygen existing as a gas collide with the substrate. This collision of oxygen ions damages the organic EL layer before forming the transparent electrode when the transparent electrode of the top emission type organic EL light emitting element is laminated by sputtering. A method for avoiding this is a method using the embodiments shown in FIGS. Next, a method for keeping oxygen ions, which are harmful substances, away from the substrate will be described with reference to the embodiments of FIGS.

  In the case of the method using the sputtering apparatus shown in FIG. 2, a bias power source 20 is connected to the substrate holder 19 and a negative bias is applied to the substrate holder 19 during the aforementioned sputtering. When a negative bias is applied to the substrate holder 19 during sputtering, oxygen ions that collide with the substrate surface together with the target material during sputtering are negative ions such as oxygen ions on the substrate surface placed on the substrate holder 19. Therefore, the damage to the substrate surface due to the collision of oxygen ions can be suppressed. Although FIG. 2 applies a negative bias to the substrate holder 19, it is also possible to apply a negative bias directly to the substrate 21. However, when used for laminating transparent electrodes of organic EL light-emitting elements, the organic EL light-emitting elements are often laminated on an insulating substrate (glass or plastic), and therefore there is a case where a bias cannot be applied directly to the substrate. . In such a case, it is effective to apply a bias to the substrate holder as shown in FIG. The bias to be applied is 0V to -600V (excluding 0V), preferably 0V to -400V (excluding 0V), more preferably -200V to -300V, and most preferably -300V. This is because it is effective to apply an opposite bias that is about the same as the voltage (Vdc) applied to oxygen ions during sputtering (up to about 2 to 3 times). A bias lower than −600 V is not preferable because it hinders the lamination of the transparent electrode.

  In the case of the method using the sputtering apparatus shown in FIG. 3, a bias power source 20 is connected to the shielding plate 22 between the substrate 21 and the electrode 17, and a bias is applied to the shielding plate 22 during the aforementioned sputtering. To do. In this way, during sputtering, negative ions such as oxygen ions that collide with the target material together with the target material do not pass through the shielding plate 22 that is negatively biased, and the oxygen ions reach the substrate 21. This can prevent the damage of the surface of the organic EL layer due to the collision of oxygen ions. The shielding plate 22 is a conductive plate having a hole, and specifically, a plate obtained by attaching a conductive metal to SUS or an aluminum plate by plating or the like can be considered. SUS is preferred. The shielding plate is larger than the substrate holder and has one or more holes having a diameter of 0.1 mm to 10 mm, preferably 0.1 mm to 2 mm. The number of holes is such that the target particles can reach the substrate through the holes and can be stacked, and is appropriately changed according to the area of the shielding plate. This hole can penetrate neutral particles but cannot pass negative ions such as oxygen ions. The distance between the shielding plate 22 and the substrate 21 is 0.5 cm to 20 cm, preferably 1 cm to 10 cm. The bias applied to the shielding plate 22 is 0 V to −600 V (excluding 0 V), preferably 0 V to −400 V (excluding 0 V), more preferably −for the same reason as the bias applied to the substrate holder 19 described above. 200V to -300V, most preferably -300V.

  In the case of the method using the sputtering apparatus shown in FIG. 4, a magnetic field between the substrate 21 and the electrode 17 is formed between the substrate 21 and the electrode 17 by installing a pair of magnets 23 between the substrate 21 and the electrode 17. 24 is generated. By doing so, the path when oxygen ions collide with the substrate 21 is bent, so that the oxygen ions do not pass through the magnetic field 24 and can be prevented from reaching the substrate 21. As a result, when the transparent electrode of the organic EL light emitting device is produced by sputtering, damage to the surface of the organic EL layer before production of the transparent electrode due to collision of oxygen ions can be suppressed. The larger the magnetic flux density of the magnetic field, the greater the bending of the path when oxygen ions collide with the substrate. Therefore, the magnetic flux density is larger than 0T and not more than 0.5T (maximum magnetic flux density that can be applied at the time of filing), preferably 0.5T. The distance between the magnetic field 24 and the substrate 21 is 0.5 cm to 20 cm, preferably 1 cm to 10 cm.

  These sputtering methods are stacked until the transparent electrode has a thickness of 50 nm to 1000 nm, preferably 100 nm to 500 nm.

  These methods may be used in combination. That is, the application of a bias to the substrate holder, the substrate or the shielding plate and the application of a magnetic force parallel to the substrate are not limited to the case where they are used alone, and can be applied simultaneously.

  In the sputtering apparatus and method of the present invention, when a transparent electrode of an organic EL light emitting element is used for forming a film by a sputtering method, collision of oxygen ions generated with a target material with the organic EL layer when the transparent electrode is manufactured. Can be avoided, and damage to the organic EL layer can be suppressed. Therefore, the sputtering apparatus of the present invention can be incorporated as a transparent electrode sputtering apparatus in an organic EL light emitting device manufacturing apparatus.

  Next, an organic EL light emitting device manufacturing apparatus incorporating the sputtering apparatus of the present invention as a transparent electrode sputtering apparatus will be described.

  One embodiment of the manufacturing apparatus of the organic EL light emitting device of the present invention is shown in FIG. In the manufacturing apparatus of FIG. 5, an oxygen plasma + load / unload chamber 10, an organic vapor deposition chamber 12, a metal vapor deposition chamber 13, and a transparent electrode sputtering apparatus 14 are installed. The organic EL light-emitting device manufacturing apparatus of the present invention includes at least an organic vapor deposition chamber 12 and a transparent electrode sputtering apparatus 14, and preferably includes an oxygen plasma + load / unload chamber 10 and a metal vapor deposition chamber 13. I have. In addition, an arbitrary processing chamber may be installed. Each processing chamber is a vacuum tank and is not shown, but a vacuum pump is attached to each processing chamber so that each processing chamber can be evacuated independently. Between the processing chambers (containers) adjacent to each other in the processing chambers, gate valves 11 are respectively attached and connected, and the substrate 21 is moved by the magnetic feed throw 15 so that the substrate 21 is being manufactured. Without exposing the substrate surface to moisture or oxygen in the atmosphere, the substrate surface can be transported while maintaining a vacuum state, and the surface can be kept clean.

  Next, each part of the manufacturing apparatus of the organic EL light emitting device of the present invention will be described.

  The oxygen plasma + load / unload chamber 10 is a carry-in port for introducing a substrate laminated to the reflective electrode. An apparatus capable of performing oxygen plasma treatment is installed in the treatment chamber, and the surface of the substrate can be modified by performing oxygen plasma treatment on the loaded substrate. In FIG. 5, the load / unload chamber and the oxygen plasma processing chamber are described as one processing chamber, but may be separate processing chambers. In FIG. 5, two oxygen plasma + load / unload chambers 10 are installed in front of the metal deposition chamber 13 as a carry-in port and behind the transparent electrode sputtering device 14 as a carry-out port. The arrangement can be changed as appropriate. For example, a structure in which one oxygen plasma + load / unload chamber 10 is installed, and a substrate can be taken in and out from the structure.

  Next, the processing chamber connected to the oxygen plasma + load / unload chamber 10 by the gate valve 11 is an organic vapor deposition chamber 12. This organic vapor deposition chamber 12 is a chamber for producing an organic EL layer. In the apparatus of FIG. 5, the organic vapor deposition chamber 12 is a single processing chamber, but may be a plurality of processing chambers. In this apparatus, a conventional vacuum deposition apparatus such as a crucible filled with materials of each layer of the organic EL layer and a means for heating the crucible is installed.

  Next, the processing chamber connected to the organic vapor deposition chamber 12 by the gate valve 11 is a metal vapor deposition chamber 13. The metal deposition chamber 13 is a chamber for producing an ultrathin film by vacuum deposition when the transparent electrode has a plurality of structures with an ultrathin film (10 nm or less) such as an electron injecting metal. In this apparatus, a conventional vacuum vapor deposition apparatus such as a crucible filled with a material of an ultrathin film and a means for heating the crucible is installed.

  Next, the transparent electrode sputtering apparatus 14 is connected to the metal deposition chamber 13 by the gate valve 11. The sputtering apparatus 14 is the above-described sputtering apparatus of the present invention, and is a chamber for laminating transparent electrodes by a sputtering method. The embodiment of the present invention as shown in FIGS. 2 to 4 is used for the sputtering device 14, and the transparent electrode is laminated by the sputtering method as described above. Thereby, damage to the surface of the organic EL layer when oxygen ions collide with the target material on the organic EL layer before the transparent electrode is formed can be avoided. An oxygen plasma + load / unload chamber 10 is attached to the sputtering apparatus 14, and a completed organic EL light-emitting element can be carried out in the direction of the arrow by producing a transparent electrode with the sputtering apparatus 14.

  These devices can be operated as follows. First, the substrate laminated up to the reflective electrode is carried from the oxygen plasma + load / unload chamber 10 and surface modification is performed by oxygen plasma treatment. Next, the substrate is moved to the organic vapor deposition chamber 12, and after laminating the organic EL layer, the substrate is moved to the metal vapor deposition chamber 13 to deposit an ultrathin film. Thereafter, the substrate is moved to the transparent electrode sputtering apparatus 14, the transparent electrodes are stacked, and carried out of the oxygen plasma + load / unload chamber 10.

  Next, a method for manufacturing an organic EL light emitting device using the above-described organic EL light emitting device manufacturing apparatus will be described.

  The method for producing an organic EL light emitting device of the present invention includes a step of laminating a reflective electrode on at least a support substrate, a step of forming an organic EL layer on the reflective electrode, and a step of forming a transparent electrode on the organic EL layer, including. Each step will be described below based on the above-described apparatus of the present invention (FIG. 5).

  The first step is a step of laminating the reflective electrode on the support substrate.

  It can be laminated on the support substrate using methods known in the art such as vapor deposition, sputtering, CVD, ion plating or laser ablation. In this specification, a support substrate refers to a substrate that is the basis of an organic EL light-emitting element on which nothing is stacked, and the substrate is an entire substrate in which an electrode, an organic EL layer, and the like are stacked on a support substrate. Point to. Next, the laminated reflective electrode is patterned. The patterning method can be performed by a conventional method such as photolithography. The thickness of the reflective electrode is 20 nm or more, preferably 70 to 150 nm.

  When a transparent conductive oxide is used as the reflective electrode, a metal such as Al, Ag, Mo, or W or an alloy thereof, an amorphous metal or alloy such as NiP, NiB, CrP, or CrB, or a microcrystal such as NiAl It is necessary to reflect the light emitted from the organic light emitting layer toward the transparent electrode by forming a laminated structure with a reflective metal layer such as a conductive alloy. The reflective metal layer is laminated using methods known in the art such as vapor deposition, sputtering, CVD, ion plating or laser ablation, and the thickness of the reflective metal layer is 10 nm to 1000 nm, preferably 100 nm. It has a thickness of ˜500 nm. If necessary, the surface of the transparent conductive metal oxide may be treated with UV, plasma, or the like to improve the hole injection property for the organic EL layer.

  The second step is a step of forming an organic EL layer on the reflective electrode. From this step, the organic EL light emitting device production apparatus of the present invention (FIG. 5) can be used.

  First, the substrate on which the reflective electrodes are stacked is carried into the oxygen plasma + load / unload chamber 10. The inside of the oxygen plasma + load / unload chamber 10 is depressurized by an attached vacuum pump, and then surface modification is performed by oxygen plasma treatment.

  Next, the board | substrate which laminated | stacked the reflective electrode is moved to the chamber for organic vapor deposition, and an organic EL layer is formed to normal thickness by vacuum vapor deposition. The organic EL layer includes, for example, a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, and / or an electron injection layer, but is not limited thereto.

  The third step is a step of forming a transparent electrode on the organic EL layer.

  On the support substrate, the substrate 21 in which the reflective electrode and the organic EL layer are laminated by the above process is moved to the sputtering apparatus 14, and a transparent electrode is produced by the sputtering method. The embodiment of the present invention as shown in FIGS. 2 to 4 is used for the sputtering device 14, and the transparent electrode is laminated by the sputtering method as described above. Thereby, damage to the surface of the organic EL layer when oxygen ions collide with the target material on the organic EL layer before the transparent electrode is formed can be avoided.

  The transparent electrode may have a plurality of structures with an ultrathin film (10 nm or less) such as an electron injecting metal. In this case, the substrate laminated up to the organic EL layer in the above step is moved to the metal vapor deposition chamber 13 before the transparent electrode is laminated by the sputtering apparatus 14 and a very thin film having a thickness of 10 nm or less is produced by vacuum vapor deposition. Is required.

  A transparent electrode is produced by this process, and an organic EL light emitting element is completed. The completed organic EL light-emitting element is moved from the sputtering apparatus 14 to the oxygen plasma + load / unload chamber 10 by the magnetic feed throw 15 and then carried out of the manufacturing apparatus.

  Next, the general structure of the organic EL light emitting device produced by the method and apparatus for producing the organic EL light emitting device of the present invention will be described.

  An example of the top emission type organic EL light emitting device produced by the present invention is shown in FIG. In the organic EL light emitting device of FIG. 6, a reflective electrode 2, an organic EL layer 3, and a transparent electrode 4 are laminated on a support substrate 1. Therefore, the light emitted from the organic light emitting layer is extracted in the direction of the arrow opposite to the support substrate. Each layer will be described below.

  The support substrate 1 used in the present invention is preferably one that can withstand the conditions (solvent, temperature, etc.) used to form the layer to be laminated and is excellent in dimensional stability. A preferable support substrate 1 is an insulating substrate made of glass, plastic, ceramic, or the like, a substrate in which an insulating thin film is formed on a conductive substrate such as semiconductive or metal, or polyolefin, acrylic resin, polyester resin, or polyimide resin. A flexible film formed from can be used.

  The reflective electrode 2 functions to reflect light emitted from the organic EL layer 3 toward the transparent electrode, and is used as either an anode or a cathode for injecting holes or electrons into the organic EL layer.

  When the reflective electrode is used as an anode, the reflective electrode is formed of a material having a high work function in order to improve hole injection properties. Suitable materials include transparent conductive oxides such as ITO or IZO. When a transparent conductive oxide is used for the reflective electrode, a metal such as Al, Ag, Mo, or W or an alloy thereof, an amorphous metal or alloy such as NiP, NiB, CrP, or CrB, or a microcrystalline property such as NiAl It is necessary to reflect light emitted from the organic EL layer toward the transparent electrode by using a laminated structure with a reflective metal layer such as an alloy. If necessary, the surface of the transparent conductive metal oxide may be treated with UV, plasma, or the like to improve the hole injection property for the organic EL layer.

  When the reflective electrode is used as a cathode, the reflective electrode is formed of a material having a low work function in order to impart electron injectability. Suitable materials are preferably alkali metals such as Li and Na, alkaline earth metals such as K, Ca, Mg, and Sr, fluorides thereof, electron injecting metals such as Al, or alloys thereof. In order to achieve good film formability and low resistivity, it is preferable to use an aluminum alloy (particularly, an alloy with an alkali metal or an alkaline earth metal), an AgMg alloy, or the like. Also in this case, a laminated structure with the above-described reflective metal layer may be employed.

  The reflective electrode can be formed using a method known in the art such as vapor deposition, sputtering, CVD, ion plating, or laser ablation. The thickness of the reflective electrode is 20 nm or more, preferably 70 to 150 nm.

  The organic EL layer 3 is a layer that emits light in the near ultraviolet to visible region, preferably in the blue to blue-green region, upon injection of holes and electrons. An organic EL layer 3 that emits white light may be used.

The organic EL layer 3 includes at least an organic light emitting layer 7 and has a structure in which a hole injection layer 5, a hole transport layer 6, an electron transport layer 8 and / or an electron injection layer 9 are interposed as required. Specifically, those having the following layer structure are employed.
(1) Organic light emitting layer 7
(2) Hole injection layer 5 / organic light emitting layer 7
(3) Organic light emitting layer 7 / electron injection layer 9
(4) Hole injection layer 5 / organic light emitting layer 7 / electron injection layer 9
(5) Hole injection layer 5 / hole transport layer 6 / organic light emitting layer 7 / electron injection layer 9
(6) Hole injection layer 5 / hole transport layer 6 / organic light emitting layer 7 / electron transport layer 8 / electron injection layer 9
(In the above, the anode is connected to the organic light emitting layer 7 or the hole injection layer 5, and the cathode is connected to the organic light emitting layer 7 or the electron injection layer 9).

  Known materials are used as the material for each of the above layers. In order to obtain light emission from blue to blue-green, in the organic light emitting layer 7, for example, fluorescent brighteners such as benzothiazole, benzimidazole and benzoxazole, metal chelated oxonium compounds, styrylbenzene compounds, aromatics Group dimethylidin compounds are preferably used. Or you may form the organic light emitting layer 7 which emits the light of the various wavelength range containing white light by adding a dopant to a host compound. As the host compound, a distyrylarylene compound, N, N′-ditolyl-N, N′-diphenylbiphenylamine (TPD), aluminum tris (8-quinolinolato) (Alq), or the like can be used. As dopants, perylene (blue purple), coumarin 6 (blue), quinacridone compounds (blue green to green), rubrene (yellow), 4-dicyanomethylene-2- (p-dimethylaminostyryl) -6-methyl- 4H-pyran (DCM, red), platinum octaethylporphyrin complex (PtOEP, red), or the like can be used.

  The material of the electron injection layer 9 may be a thin film (thickness of 10 nm or less) of an electron injection material such as an alkali metal, an alkaline earth metal, an alloy containing them, or an alkali metal fluoride. Alternatively, an aluminum quinolinol complex doped with an alkali metal or an alkaline earth metal may be used.

Examples of the material for the electron transport layer 8 include oxadiazole derivatives such as 2- (4-biphenyl) -5- (pt-butylphenyl) -1,3,4-oxadiazole (PBD), triazole derivatives, Triazine derivatives, phenylquinoxalines, aluminum quinolinol complexes (eg, Alq ₃ ), and the like can be used.

  Examples of the material for the hole transport layer 6 include TPD, N, N′-bis (1-naphthyl) -N, N′-diphenylbiphenylamine (α-NPD), 4,4 ′, 4 ″ -tris (N— Known materials including triarylamine-based materials such as 3-tolyl-N-phenylamino) triphenylamine (m-MTDATA) can be used.

  As a material for the hole injection layer 5, phthalocyanines (such as copper phthalocyanine) or indanthrene compounds can be used.

  The transparent electrode 4 becomes a cathode when the above-mentioned reflective electrode 2 is an anode, and becomes an anode when the above-mentioned reflective electrode 2 is a cathode.

  When the transparent electrode 4 is used as a cathode, the material is required to have a small work function in order to inject electrons efficiently. Furthermore, it is required to be transparent in the wavelength range of light emitted from the organic EL layer 3. In order to achieve both of these two characteristics, it is preferable that the transparent electrode 4 has a laminated structure composed of a plurality of layers. This is because a material having a low work function generally has low transparency. That is, an electron-injecting metal made of an alkali metal such as lithium or sodium, an alkaline earth metal such as potassium, calcium, magnesium, or strontium, or a fluoride thereof, etc. An ultrathin film (10 nm or less) of an alloy or compound with a metal is used. By using these materials having a low work function, it is possible to achieve efficient electron injection, and by using an ultra-thin film, it is possible to minimize the decrease in transparency due to these materials. A transparent conductive film such as ITO or IZO is formed on the ultrathin film. These conductive films function as auxiliary electrodes, reduce the resistance value of the entire transparent electrode, and allow a sufficient current to be supplied to the organic EL layer 3.

  When the transparent electrode 4 is used as an anode, it is necessary to use a material having a large work function in order to increase the hole injection efficiency. In addition, since light emitted from the organic EL layer 3 passes through the transparent electrode 4, it is necessary to use a highly transparent material. Therefore, in this case, it is preferable to use a transparent conductive material such as ITO or IZO.

  The transparent electrode 4 is laminated by sputtering by the method or apparatus of the present invention. The transparent electrode 4 preferably has a transmittance of 50% or more, more preferably 85% or more with respect to light having a wavelength of 400 to 800 nm. In order to improve luminous efficiency, it is desirable that the transparent electrode has a thickness that provides a sufficiently low resistivity, preferably 30 nm or more, and more preferably within a range of 100 to 300 nm.

  Next, the shapes of the reflective electrode and the transparent electrode will be described. There are two types of driving methods for organic EL light emitting devices, passive type and active type, and the shape of the electrode differs depending on which driving method is selected, but in the case of top emission type organic EL devices, the active type is used. It is done. In the case of the active type, a switching element (TFT or the like) corresponding to the light emitting part is formed on the substrate in a one-to-one correspondence, and the switching element is in a one-to-one correspondence with a reflective electrode composed of a plurality of partial electrodes. Corresponding connections are made, and a structure is combined with the transparent electrode 4 formed integrally on the organic EL layer 3.

  A color filter layer or a color conversion layer may be further provided on the organic EL layer 3 to form an organic EL light emitting element that emits light of a desired hue. The color filter layer is a layer that transmits only light in a specific wavelength region among light emitted from the organic light emitting layer 7. The color conversion filter is a layer that performs so-called wavelength distribution conversion that absorbs a component in a specific wavelength range of light emission from the organic EL layer 3 and emits light in another wavelength range. For example, a red conversion layer that absorbs blue to blue-green components and emits red light may be provided. A color conversion layer and a color filter layer may be used in combination to improve the color purity of emitted light. Furthermore, when using an organic EL light emitting device having a plurality of light emitting units controlled independently, it is possible to form a multicolor display by combining a plurality of types of color filter layers or color conversion layers. The color conversion layer and the color filter layer can be formed of any material known in the art.

  The color filter layer or the color conversion layer is laminated on the transparent electrode 4 or formed on a separate substrate, and then bonded to the organic EL light emitting element.

  Next, the manufacturing apparatus and manufacturing method of the organic EL light emitting device of the present invention described above will be described more specifically with reference to examples. Needless to say, they do not limit the present invention and can be variously modified without departing from the gist of the present invention.

  An organic EL light-emitting element was produced using the organic EL light-emitting element manufacturing apparatus of FIG. 5, and the effect of the organic EL light-emitting element manufacturing apparatus and method of the present invention on luminance current efficiency was tested.

  On a glass support substrate having dimensions of 5 cm × 5 cm, Al was deposited as a reflective metal to a thickness of 100 nm, and ITO was deposited thereon as a reflective electrode to a thickness of 100 nm by a sputtering method. The substrate was then polished and patterned using photolithography. Aqua regia was used as an etchant for ITO and Al.

The substrate on which the reflective electrode was formed was washed and then carried from the oxygen plasma + load / unload chamber 10 to the organic EL light emitting device manufacturing apparatus of FIG. Using the oxygen plasma apparatus attached to the oxygen plasma + load / unload chamber 10, the substrate on which the reflective electrode was formed was surface-modified at 100 W for 5 minutes in an Ar / O ₂ = 1: 1 atmosphere. Next, this board | substrate was carried in to the chamber for organic vapor deposition, and vapor deposition of the organic EL layer was started. As a hole transport layer, α-NPD was deposited at a thickness of 40 nm at 0.5 nm / s, and then Alq was deposited as an organic light emitting layer at a thickness of 60 nm at 0.5 nm / s. The pressure during vapor deposition was 5 × 10 ⁻⁵ Pa, and film formation was performed at room temperature. Next, the substrate laminated up to the organic EL layer was moved to the sputtering apparatus 14, and IZO was laminated as a transparent electrode by sputtering. The sputtering apparatus includes a pair of magnets 23 between the sputtering apparatus of the embodiment that applies a bias to the substrate holder as shown in FIG. 2 and the substrate and the electrode 17 as shown in FIG. The sputtering apparatus according to the embodiment that generates the magnetic field 24 in parallel with the substrate between the substrate and the electrode 17 was used. In the case of the embodiment in which a bias is applied to the substrate holder, as a comparative example, the case where the bias is 0V and the case where the bias is −200V are performed as Example 1. In the embodiment in which the magnetic field 24 is generated between the substrate and the electrode 17, a magnetic flux density of 0.3 T is applied as Example 2. As for other sputtering conditions, the gas type was Ar, the gas pressure was 0.5 Pa to 1 Pa, the electric energy was DC100W or DC100W and RF50W, and the substrate temperature was room temperature. Under the above conditions, 75 nm of IZO was laminated at 20 nm / min.

  The organic EL light emitting elements of Comparative Example 1, Examples 1 and 2 were produced by the above production process. The current efficiency of these luminances was measured by normal current-voltage-luminance. The results are shown in Table 1.

  As shown in Table 1, Example 1 in which a bias of −200 V was applied to the substrate holder and the organic EL light emitting device in which a magnetic force of 0.3 T was applied between the substrate and the electrode were 2.7 to 2.8 cd / A. While showing high current efficiency, the comparative example which did not apply bias and magnetic force had current efficiency as low as 2.0 cd / A. This result was the same even when DC and RF were applied simultaneously. This is probably because oxygen ions cannot reach the substrate directly by using the apparatus of the present invention, the damage given to the organic EL layer is reduced, and the current efficiency of the top emission type organic EL light emitting element is improved. .

  Moreover, the current efficiency of the bottom emission type organic EL light emitting device having the same configuration as that of the top emission type organic EL light emitting device except that the cathode is Al was 2.8 cd / A. Therefore, the top emission type organic EL light emitting device produced according to the present invention has a current efficiency equivalent to that of the bottom emission type organic EL light emitting device.

  According to the present invention, it is possible to reduce the collision of oxygen ions to the substrate laminated up to the organic EL layer, and to minimize damage to the organic EL layer. Conventionally, when producing a transparent electrode for a top emission type by sputtering, the characteristics are lower than those of a bottom emission type. However, according to the present invention, an organic EL light emitting device having the same characteristics as the bottom emission type is produced. Became possible.

It is the figure which showed the relationship between the brightness | luminance and voltage of the organic electroluminescent light emitting element which vapor-deposited Al after irradiating oxygen plasma or Ar plasma. It is the figure which showed roughly the structure of the sputtering device of this invention in the case of applying a bias to a substrate holder. It is the figure which showed roughly the structure of the sputtering device of this invention in the case of applying a bias to a shielding board. It is the figure which showed roughly the structure of the sputtering device of this invention in the case of applying a magnetic force in parallel with a board | substrate. It is a schematic diagram which shows one Embodiment of the manufacturing apparatus of the organic EL light emitting element of this invention. It is a cross-sectional schematic diagram which shows the structure of a top emission type organic EL light emitting element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Support substrate 2 Reflective electrode 3 Organic EL layer 4 Transparent electrode 5 Hole injection layer 6 Hole transport layer 7 Organic light emitting layer 8 Electron transport layer 9 Electron injection layer 10 Oxygen plasma + load / unload chamber 11 Gate valve 12 Organic vapor deposition Chamber 13 Metal deposition chamber 14 Sputtering device 15 Magnetic feed throw 16 DC sputtering power source 17 Electrode 18 Target 19 Substrate holder 20 Bias power source 21 Substrate 22 Shielding plate 23 Magnet 24 Magnetic field 25 RF sputtering power source

Claims (17)

In a sputtering apparatus for producing a transparent electrode of a top emission type organic EL light emitting device including at least an electrode, a target, a substrate, and a substrate holder for holding the substrate in a vacuum chamber, the device has means for preventing harmful substances from coming close to the substrate , The means
a) means for applying a bias to the substrate holder;
b) a means for providing a shielding plate between the substrate and the electrode and applying a bias to the shielding plate; and c) one selected from means for applying a magnetic field parallel to the substrate between the substrate and the electrode, or A sputtering apparatus comprising a plurality of means.   The sputtering apparatus according to claim 1, wherein the harmful substance is oxygen ions.   The sputtering apparatus according to claim 1, wherein the bias to be applied is 0 V to −600 V (excluding 0 V).   The sputtering apparatus according to claim 1 or 2, wherein the magnetic flux density of the applied magnetic force is larger than 0T and not larger than 0.5T. A method for forming a transparent electrode on a substrate using a sputtering apparatus for producing a transparent electrode of a top emission type organic EL light emitting device including at least an electrode, a target, a substrate and a substrate holder for holding the substrate in a vacuum chamber,
a) applying a bias to the substrate holder;
b) one selected from providing a shielding plate between the substrate and the electrode and applying a bias to the shielding plate; and c) applying a magnetic field parallel to the substrate between the substrate and the electrode, or A method comprising a method of keeping a plurality of harmful substances away from a substrate.   The method according to claim 5, wherein the harmful substance is an oxygen ion.   The method according to claim 5 or 6, wherein the bias to be applied is 0 V to -600 V (excluding 0 V).   The method according to claim 5 or 6, wherein the magnetic flux density of the applied magnetic force is larger than 0T and not larger than 0.5T. A top emission type organic EL light-emitting device manufacturing apparatus including at least an organic vapor deposition chamber and a transparent electrode manufacturing sputtering apparatus, the transparent electrode manufacturing sputtering apparatus having means for keeping harmful substances away from the substrate, Said means is
a) means for applying a bias to the substrate holder;
b) a means for providing a shielding plate between the substrate and the electrode and applying a bias to the shielding plate; and c) one selected from means for applying a magnetic field parallel to the substrate between the substrate and the electrode, or A manufacturing apparatus comprising a plurality of means.   The manufacturing apparatus according to claim 9, wherein the harmful substance is an oxygen ion.   The manufacturing apparatus according to claim 9 or 10, wherein a bias to be applied is 0 V to -600 V (excluding 0 V).   The manufacturing apparatus according to claim 9 or 10, wherein the magnetic flux density of the applied magnetic force is larger than 0T and not larger than 0.5T.   The manufacturing method according to any one of claims 9 to 12, wherein the organic vapor deposition chamber and the transparent electrode manufacturing sputtering apparatus are connected so that the substrate can be conveyed while maintaining a vacuum. apparatus. In the method of manufacturing a top emission type organic EL light emitting device, the method includes the step of laminating the transparent electrode in the method for producing a top emission type organic EL light emitting device including the step of laminating at least the reflective electrode on the support substrate, the step of laminating the organic EL layer, and the step of laminating the transparent electrode. Is a step of forming a film on a substrate using a sputtering apparatus including at least an electrode, a target, a substrate, and a substrate holder for holding the substrate in a vacuum chamber. During this step,
a) applying a bias to the substrate holder;
b) one selected from providing a shielding plate between the substrate and the electrode and applying a bias to the shielding plate; and c) applying a magnetic field parallel to the substrate between the substrate and the electrode, or A manufacturing method characterized in that a film is formed while applying a method that keeps a plurality of harmful substances away from a substrate.   The manufacturing method according to claim 14, wherein the harmful substance is an oxygen ion.   The manufacturing method according to claim 14 or 15, wherein the bias to be applied is 0 V to -600 V (excluding 0 V). The manufacturing method according to claim 14 or 15, wherein the magnetic flux density of the applied magnetic force is larger than 0T and not larger than 0.5T.

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