JP2008027648A - Transparent conductive film forming method, and manufacturing method of organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that, in case a transparent conductive film is formed by a sputtering method, a molecular structure of an organic thin film is destroyed (bond-break) by scattering and collision of recoil Ar ions, γ electrons, target particles or the like which are high-energy particles to degrade a light emission potential that an organic light-emitting material intrinsically has. <P>SOLUTION: In the transparent conductive film forming method providing a mask on a substrate and pattern-forming the transparent conductive film on the substrate by the sputtering method, a trap electrode equipped with a pin made of a magnet is provided between the target and the substrate, and the transparent conductive film made of a target-forming material is pattern-formed on the substrate by the sputtering method. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for forming a transparent electrode using a sputtering method, and also relates to a method for manufacturing an organic electroluminescent element using the method for forming a transparent electrode.

  The fields of application of transparent conductive films are diversified, such as optical communications, semiconductor lasers, various displays, recording media, consumer devices (digital cameras, projectors, mobile phones, lenses, mirrors, lamps, etc.). Has become an important requirement for stability during mass production, such as yield improvement, and for film performance during multilayer film formation.

  An organic electroluminescent element has a structure in which an organic light emitting layer is sandwiched between two electrodes, and the organic light emitting layer emits light by passing a current between the electrodes. One of the electrodes must be transparent. It has been proposed to use a transparent conductive film made of indium / tin oxide (ITO) or the like as the transparent electrode (for example, Patent Documents 1, 2, 3, and 4).

  An organic electroluminescence device of the top light extraction (top emission) type uses a transparent electrode on the opposite side of the substrate. At this time, a transparent conductive film is formed on the metal thin film to protect the cathode. It has been proposed to reduce the wiring resistance. In order to use the transparent conductive film as a cathode, it has been proposed to sandwich a buffer layer between the organic light emitting layer and the transparent conductive film for the purpose of protecting the underlying organic light emitting layer and reducing the electron injection barrier. For the formation of the transparent conductive film, the conventional deposition methods, as well as the plasma and ion beam assisted deposition methods, ion plating methods, ion beam sputtering methods, etc. that have been used in recent years for optical communications are mainly used. In addition, a wet method such as a sol / gel method or a spray method may be used. On the other hand, there is a sputtering method as a method used in mass production apparatuses in thin film manufacturing processes such as semiconductors, flat panel displays, and electronic components. The sputtering method is widely used as a method suitable for mass production because the film formation rate and film composition are stable and uniform film formation on a large area substrate is possible. Furthermore, it has become mainstream because of its high uniformity of film thickness, conductivity and transparency, and excellent fine etching characteristics.

The known literature is shown below.
JP 2003-901158 A JP 2001-250678 A Japanese Patent No. 2850906 JP 2005-68501 A

  When a conductive film is patterned on a substrate by a vapor deposition method, the vapor deposition method deposits particles on the substrate with only thermal energy, and thus the energy of particles incident on the substrate is about 0.1 eV. On the other hand, when a transparent conductive film is patterned on a substrate by sputtering, the energy of particles incident on the substrate is as high as about 600 eV. In general, when the energy of particles incident on the substrate is about 50 eV or more, there are problems that particles enter the substrate, atoms constituting the substrate are knocked out, or defects are generated in the substrate.

In particular, when a transparent conductive film is formed on an organic thin film by sputtering, the molecular structure of the organic thin film is destroyed (bond breakage) due to scattering and collision of recoil Ar ions, γ electrons, target particles, etc., which are high energy particles. There is a problem that the light emission potential inherent to the organic light emitting material is lowered.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a transparent conductive film forming method in which a mask is provided on a substrate and a transparent conductive film is patterned on the substrate by a sputtering method. A trapping electrode having a pin is provided, and a transparent conductive film made of a target forming material is patterned on the substrate by a sputtering method, so that γ electrons can be captured by the method of forming a transparent conductive film. did.

  According to a second aspect of the present invention, the magnet has a conical shape, a plurality of the magnets are arranged in a circle on the outer periphery of the trap, and the polarity of the magnet is set so that a line of magnetic force extends in the trap electrode surface. The transparent conductive film forming method according to claim 1, wherein the transparent conductive film is oriented so as to be circulated.

  According to a third aspect of the present invention, a positive potential is applied to the trap electrode with magnet from the substrate to attract plasma charged particles to the tip of the magnet and the trap electrode by electrostatic induction, thereby neutralizing the polarity of the charged particles. 3. The method of forming a transparent conductive film according to claim 2, wherein the plasma charged particles are attracted to the magnetic field lines oriented so as to be stretched around the trap electrode surface. Can be reduced.

  According to a fourth aspect of the present invention, the transparent conductive film forming method according to any one of the first to third aspects, wherein the substrate is cooled by a Peltier element during the formation of the transparent conductive film. did.

  According to a fifth aspect of the present invention, there is provided an organic electroluminescent device comprising at least a first electrode, an organic light emitting layer, and a second electrode in this order on a substrate, and causing the organic light emitting layer to emit light by passing a current between the electrodes. In this manufacturing method, at least one of the first electrode and the second electrode is patterned by the method according to any one of claims 1 to 4.

  According to a sixth aspect of the invention, there is provided a top emission type organic electroluminescence which comprises at least a reflective electrode, an organic light emitting layer and a transparent electrode on a base material in this order, and causes the organic light emitting layer to emit light by passing a current between the electrodes. In the element manufacturing method, a transparent electrode is formed by the method according to any one of claims 1 to 4, and the top emission type organic electroluminescent element manufacturing method is provided.

  Further, as an invention according to claim 7, in the method of manufacturing an organic electroluminescent element according to claim 5 or 6, the organic light emitting layer forming material is dissolved or dispersed in a solvent to form an ink, It was set as the manufacturing method of the organic electroluminescent element characterized by including the process of forming an organic light emitting layer on a base material with a letterpress reverse offset printing method using ink.

  Further, as an invention according to claim 8, in the method of manufacturing an organic electroluminescent element according to claim 5 or 6, the organic light emitting layer forming material is dissolved or dispersed in a solvent to form an ink, It was set as the manufacturing method of the organic electroluminescent element characterized by including the process of forming an organic light emitting layer on a base material with a relief printing method using ink.

  Further, as an invention according to claim 9, in the method for manufacturing an organic electroluminescent element according to claim 5, 6, 7, or 8, CaO is applied to the glass on the substrate on which the organic light emitting layer and the electrode are formed. Using the formed base material as a sealing base material, a hygroscopic effect can be imparted to the base material by using a method for producing an organic electroluminescence device characterized by bonding the two together, and drying is performed again in the sealing process. It becomes unnecessary to insert the agent.

  By forming a transparent conductive film on a substrate by a sputtering method using a trap electrode having a conical pin made of a magnet, recoil Ar ions released when Ar ions collide with the target, two Of the γ electrons, which are secondary electrons, and the target particles, it is possible to reduce the incidence of γ electrons, which are secondary electrons, on the substrate. By applying a positive voltage to the trap electrode with magnet, γ electrons are attracted to the tip of the magnet, which is a concentrated portion of electric force lines, by electrostatic attraction, and the incidence of γ electrons on the substrate is reduced.

  When a negative voltage is applied to the trap electrode with magnet, the recoil Ar ions or surplus Ar ions that do not collide with the target are attracted to the tip of the magnet by electrostatic attraction, and the polarity is neutralized (disappears). The incidence of ions on the substrate is reduced.

  By reducing the incidence of γ electrons on the substrate, for example, when the substrate has an organic thin film and a transparent conductive film is formed on the organic thin film, the organic thin film is not destroyed. It became possible to form a transparent conductive film on the thin film.

  In addition, when patterning a transparent conductive film with a metal mask using a sputtering method, thermal radiation (infrared radiation) and further leakage plasma are accompanied by a rise in temperature caused by an increase in plasma charged particle density on the target surface due to plasma confinement. Since a part of the mask is incident on the mask surface, the mask is thermally expanded and deformed. In the present invention, when a transparent conductive film is formed by sputtering, plasma charged particles such as γ electrons are captured to reduce an excessive increase in plasma charged particle density on the target surface. In particular, the thermal expansion and thermal deformation of the mask can be suppressed. Therefore, an accurate pattern can be formed on the substrate.

  In addition, in the method for producing an organic electroluminescent element, by using the transparent conductive film forming method of the present invention, it becomes possible to form a transparent electrode without damaging the base material, and an organic electroluminescent element having good light emitting characteristics. Could get. In particular, in a top emission type organic electroluminescent device, it becomes possible to form a transparent electrode on an organic thin film such as an organic light emitting layer without damaging it, and an organic electroluminescent device with good emission characteristics and low driving voltage is obtained. I was able to.

  The letterpress reverse offset printing method uses a blanket, fixes the blanket to the blanket cylinder, and transfers the patterned ink on the blanket surface to the transfer target. The pattern and thickness of the ink are controlled. There is an advantage that it is easy to do. In the method for producing an organic electroluminescent element, an organic light emitting layer having an excellent pattern shape could be obtained by forming an organic light emitting layer by using a letterpress reverse printing method.

  In addition, the relief printing method is a method in which ink is supplied to a relief plate as a printing plate and then transferred to a transfer medium. Since a highly flexible material can be used for the plate material, a substrate that easily breaks such as a glass substrate. It is excellent as a production method for forming an organic electroluminescent element on a material.

Moreover, in the manufacturing method of an organic electroluminescent element, on the base material which formed the organic light emitting layer and electrode of this invention, the base material which formed CaO on glass is used as a sealing base material, and both are bonded together, It became possible to perform sealing without inserting a desiccant. In addition, since the glass is directly bonded to the upper part of the base material, the light absorption at the sealing base material and the change in the optical path length that occurs when using a glass with a cap structure do not occur, and the light extraction efficiency is improved. I was able to.

  Hereinafter, embodiments of the present invention will be described.

Applications of the transparent conductive film used in the present invention are diverse. In particular, when it is used as an electrode for an optoelectronic device, it must satisfy the requirements according to the usage conditions of various devices. In particular, the transparent conductive film-forming material must be a material that satisfies both electrical characteristics and optical characteristics in the visible light region. As the transparent conductive film forming material in the present invention, indium oxide-based ITO (added Sn as a dopant to In ₂ O ₃ ), SnO ₂ (dopant added) in the tin oxide system, and AZO (ZnO in the zinc oxide system) are used. In addition, Al can be added as a dopant), GZO (adding Ga as a dopant to ZnO), IZO (adding In as a dopant to ZnO), and the like can be used.

  Besides these, it is possible to use CdO-based and gallium oxide-based materials. However, the CdO system is difficult to put into practical use because Cd has toxicity. Gallium oxide-based transparent conductive films also have a number of features such as having a wide band gap. However, like indium, gallium is not an abundant material from the viewpoint of resources. As described above, the transparent conductive film forming material has a social background in which the environmental aspect must be given top priority as a material design guideline.

ITO is called Indium tin oxide, but its mother crystal is In ₂ O ₃ . ITO (In ₂ O ₃ : Sn) with a composition in which Sn is added in an amount of 5 to 10 wt% in terms of oxide is transparent like an insulator, but has high conductivity (10 ⁺³ S / cm) and little absorption. . Transparency and conductivity are related to each other, but there is no one-to-one correspondence. Transparency means that the structural integrity of the In ₂ O ₃ crystal is high and the number of electron capture levels in the band gap is very small, but the atoms in the crystal are coordinate points of the crystal system (lattice position). ) Is correctly determined by whether or not it is located without excess or deficiency. The In ₂ O ₃ reagent is yellowish white, and a transparent conductive film is obtained by vapor deposition or sputter deposition in an atmosphere containing a slight amount of oxygen (partial pressure is 10 ⁻¹ Pa or less). However, as a compound, it is easy to let go of oxygen, and it is easily reduced by heating in a vacuum or in a reducing atmosphere containing several percent of hydrogen. As the reduction proceeds, the color changes from blue-black to black and further to brown. . Conductivity is manifested by substituting with In atoms or Sn atoms of the mother crystal, or by forming a film under conditions that do not give sufficient and sufficient oxygen atoms.

The physical meaning of transparency of ITO can be attributed to the fact that the band gap as a semiconductor is in the vicinity of the short wavelength limit of 400 nm in the visible region. However, this is not enough, and in order to ensure high transparency, there are few or negligible levels at which electrons are resident at room temperature in the band gap. Such bandgap levels are derived from lattice defects due to oxygen vacancies, In atoms other than Sn atoms substituted at the In position, or Sn atoms or atomic groups (clusters). It must be easy to form a lattice. In ₂ O ₃ satisfies this requirement unless the film is formed in an atmosphere having extremely weak oxidizing properties. In fact, with In ₂ O _{3, if} the glass substrate temperature is set to about 300 ° C., a well-prepared X-ray diffraction pattern with a narrow half-value width from a thickness of several tens of nanometers, even under atmospheric conditions where oxygen is slightly insufficient Indicates. Even if Sn is added, this characteristic that is easily crystallized is not lost up to about several tens of percent. This is a feature that is greatly different from the SnO ₂ film and ZnO film.

Next, it shows about the transparent conductive film formation method of this invention. In the present invention, a transparent electrode is formed on a substrate by a sputtering method, and an ion beam sputtering method, a direct current sputtering method, a high frequency sputtering method, a magnetron sputtering method, or the like can be used as the sputtering method.

  Magnetron sputtering has a high current density, and ions collide with electrons at a high energy of 600 eV, so that a transparent conductive film can be formed at high speed. In addition, the average free path of the sputtered particles is long because of the low pressure, and the thin film can be deposited by collecting the sputtered particles on the substrate opposed to the target. However, due to the high energy process, when a transparent conductive film is formed on an organic thin film, recoil Ar ions, γ electrons, and even accelerated target particles collide with the underlying organic thin film and cause great damage. have.

  A schematic diagram of a DC magnetron sputtering apparatus used for forming the transparent conductive film of the present invention is shown in FIG. In FIG. 1, a trap electrode (2) is provided between a substrate (1) and a target (10). The trap electrode (2) is provided with a magnet pin (3). The target (10) is fixed to the backing plate (OFC) (11), and a cathode magnet (12) is provided on the surface of the backing plate (11) opposite to the target (10). Yes. The inside of the apparatus is once evacuated to a high vacuum at the time of film formation, and then the argon gas or a gas obtained by adding a reactive gas such as oxygen or nitrogen to the argon gas is introduced to a pressure suitable for sputtering. It becomes.

  A voltage is applied to the trap electrode (2). By applying a voltage to the trap electrode (2), it becomes possible to capture (extinguish) plasma charged particles. Accordingly, the frequency of incidence of plasma charged particles on the mask can also be reduced, which acts as a carrier trap mechanism.

  The present invention is characterized in that a trap electrode having a magnet pin (3) is provided between a target (10) made of a transparent conductive film forming material and a substrate. By installing a trap electrode (2) with a magnet (3) between the target (10) and the substrate (1) and applying a positive voltage to the trap electrode, γ electrons are attracted to the tip of the magnet pin by electrostatic attraction, The γ electrons that could not be attracted are supplemented by magnetic lines of force formed so as to be stretched in the trap surface, thereby suppressing sputter damage and substrate charge-up due to electron collision with the substrate. In particular, when the substrate has an organic thin film on the surface and a transparent conductive film is formed on the surface of the organic thin film, the sputter damage of the organic thin film can be reduced and the transparent conductive film can be formed on the organic thin film.

The magnetic field lines in the present invention are magnetic field lines formed by a magnet installed on the trap electrode (2), and are formed so as to be stretched around the trap electrode surface. The magnetic flux density required to capture γ electrons and other charged particles is such that when the velocity of electrons in the direction perpendicular to the organic thin film is v, the Larmor radius r _L of cyclotron motion is r _L = Mv / qB. m is the mass of the charged particle, q is the amount of charge, and B is the magnetic flux density. When this Larmor radius is smaller than the distance between the sputtering target and the substrate, it is expected that charged particles are captured by the lines of magnetic force. It is necessary to design the specifications and arrangement of magnets to satisfy such conditions. Specifically, when the γ electrons have energy of 50 eV in the direction perpendicular to the substrate and the distance between the substrates is 130 mm, the magnetic flux density B for making the Larmor radius equal to this distance is B = mv / From qr _L , the required magnetic flux density is 1.8 × 10 ⁻⁴ Wb / m ² . This is a condition that can be easily produced even with a commercially available permanent magnet.

  A known permanent magnet can be used as the magnet. It is desirable that the magnet has a conical shape. The reason why it is desirable to have a conical shape is that plasma electrons can be efficiently captured using the electrostatic induction phenomenon.

  FIG. 2 shows an explanatory view of the periphery of the substrate in the transparent conductive film forming method of the invention. The substrate (1) is sandwiched between a mask (17) and a mask frame (19) and a magnet holder (16), and has a close contact structure. In the substrate (1), a transparent conductive film is patterned on the surface in close contact with the mask according to the opening shape of the mask. In the transparent conductive film forming method of the present invention, the substrate is cooled by the Peltier element (15) during the formation of the transparent conductive film. The Peltier element is provided on the magnet holder.

  The Peltier element is a semiconductor element that can easily cool the substrate and the mask by installing the Peltier element on the top of the contact substrate under vacuum. The provision of the Peltier element does not require any major modification of the apparatus, and the substrate and the mask can be easily cooled. For example, when a transparent electrode is provided on a substrate provided with an organic light emitting layer or the like in an organic electroluminescent element, the characteristics of the organic light emitting layer provided on the substrate are increased by increasing the substrate temperature due to radiant heat of plasma or the like. May deteriorate. In addition, when the mask temperature rises, the thermal expansion of the mask material may cause a shift between the mask and the substrate on which the transparent electrode is provided, which may make it difficult to form an accurate transparent electrode pattern. . The occurrence of these problems can be prevented by cooling the substrate and the mask with the Peltier element.

  FIG. 3 is an explanatory sectional view of the Peltier element. As shown in FIG. 3, the Peltier element has P-type semiconductors (23 a) and N-type semiconductors (23 b) arranged alternately between the ceramic substrates (21) via metal electrodes (22). When P-type semiconductor and N-type semiconductor are used alternately, P-type thermoelectric power has a positive sign, N-type thermoelectric power has a negative sign, and its relative thermoelectric power is very large, so that a large thermoelectric effect can be obtained. become.

  Next, the manufacturing method of the organic electroluminescent element of this invention is described. In the organic electroluminescent element of the present invention, a first electrode, an organic light emitting layer, and a second electrode are provided in this order on a substrate. Further, a hole transport layer, a hole injection layer, an electron transport layer, an electron injection layer, a charge generation layer, and the like are provided as necessary between the first electrode and the second electrode as a light emission auxiliary layer. The first electrode, the organic light emitting layer, and the second electrode provided on the substrate are sealed for the purpose of protecting both the electrodes, the organic light emitting layer, and the like from moisture in the environment. As sealing, a method in which a glass cap or a metal cap is bonded to a base material, or a method in which a base material provided with a first electrode, an organic light emitting layer, or a second electrode is covered with a barrier layer or the like can be used. .

  One of the first electrode and the second electrode is an anode, and the other is a cathode. An organic electroluminescent element is a device that emits light from an organic light emitting layer by passing an electric current between electrodes. A method of taking out emitted light from a substrate side is a bottom emission method, and a method of taking out light from a side opposite to a substrate. This is called the top emission method. In the bottom emission method, it is necessary to make the layer on the substrate side transparent with respect to the organic light emitting layer in order to transmit light emitted from the organic light emitting layer. That is, the base material and the first electrode need to have transparency. On the other hand, in a top emission type organic electroluminescent device, the layer on the side opposite to the substrate with respect to the organic light emitting layer needs to be transparent in order to transmit light emitted from the organic light emitting layer. That is, the second electrode needs to have transparency, and it is necessary to prevent light from being blocked by sealing.

  FIG. 4 shows an explanatory sectional view of a top emission type organic electroluminescent element. On the base material (25), a reflective electrode (26) is patterned as a first electrode, a partition wall (27) is formed between the reflective electrodes (26), and a hole transport layer is formed on the reflective electrode (26). (28), an organic light emitting layer (29a, 29b, 29c) is provided in this order; an electron injecting protective layer (32) on the organic light emitting layer (29a, 29b, 29c); and a transparent electrode ( 33). A reflective electrode (26), a partition wall (27), a hole transport layer (28), an organic light emitting layer (29a, 29b, 29c), an electron injecting protective layer (32), and a transparent electrode (33) were provided. The base material is sealed with a barrier layer (34), a resin layer (35), and a sealing base material (36). In addition, a substrate provided with a reflective electrode, a partition wall, a hole transport layer, an organic light emitting layer, an electron injecting protective layer, and a transparent electrode is directly bonded to a glass substrate on which CaO is formed as a desiccant and sealed. May be.

  In the top emission type organic electroluminescence device of the present invention, as the substrate (25), a glass substrate or a plastic film or sheet can be used. If a plastic film is used, an organic electroluminescent element can be manufactured by winding, and the element can be provided at low cost. As the plastic film material, for example, polyethylene terephthalate, polypropylene, cycloolefin polymer, polyamide, polyethersulfone, polymethyl methacrylate, polycarbonate and the like can be used. Moreover, you may laminate | stack other gas-barrier films, such as a ceramic vapor deposition film, a polyvinylidene chloride, a polyvinyl chloride, and an ethylene-vinyl acetate copolymer saponified material, on the side which does not form an electrode. Further, when the organic electroluminescent element is an active matrix organic electroluminescent element, it is necessary to use a TFT substrate having a thin film transistor (TFT) as a substrate.

  There are a passive matrix type and an active matrix type as a driving method of the organic electroluminescent element. The organic electroluminescent element of the present invention is either a passive matrix type organic electroluminescent element or an active matrix type organic electroluminescent element. Applicable. The passive matrix method is a method in which stripe-shaped electrodes are opposed to each other so as to be perpendicular to each other with an organic light emitting layer interposed therebetween, and light is emitted at the intersection. On the other hand, the active matrix method is a so-called thin film transistor in which a transistor is formed for each pixel ( This is a method of emitting light independently for each pixel by using a TFT) substrate. As the thin film transistor (TFT), an amorphous silicon or polysilicon thin film transistor (TFT) is used.

  In the passive matrix organic electroluminescence device, the lighting time in each pixel is shortened as the number of stripe-shaped electrodes to be scanned increases, so that it is necessary to increase the instantaneous light emission luminance in the ON state. When the instantaneous light emission luminance is increased, the lifetime of the element is reduced, so that it is not suitable for a large-capacity display that requires hundreds to thousands of electrodes on the stripe to be scanned. On the other hand, each active matrix organic electroluminescent element has a switching element and a memory element (active element) for each pixel, so that the operation state can be maintained for one scanning cycle. Even if the size is increased, the instantaneous luminance may be small and the durability is excellent. Moreover, it is advantageous for displaying moving images that require a high-speed response such as a display.

  The reflective electrode (26), which is the first electrode, can be formed as a positive electrode by using a metal material such as Mg, Al, or Cr by a vacuum film formation method such as a vapor deposition method or a sputtering method. Further, the reflective electrode may have a two-layer structure of a reflective electrode such as Mg, Al, and Cr and a transparent electrode such as ITO. At this time, ITO is provided as an anode interface layer.

  After the formation of the reflective electrode (26), a partition wall (27) is formed between the reflective electrodes so as to cover the edge of the reflective electrode. The partition wall needs to have insulating properties, and a photosensitive material or the like can be used. The photosensitive material may be a positive type or a negative type, and a novolac resin, a polyimide resin, or the like can be used, and a partition wall is formed through an exposure process and a development process by a photolithography method.

  A hole transport layer (28) is provided on the reflective electrode (26). As the hole transport layer forming material, poly (3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (PEDOT / PSS) or the like can be used. PEDOT / PSS is dissolved in water to form a coating solution, which is coated on a substrate by a spin coating method or the like and dried.

  On the hole transport layer (28), organic light emitting layers (29a, 29b, 29c) are provided. When organic electroluminescent elements are displayed in full color, it is necessary to pattern organic light emitting layers having red (R), green (G), and blue (B) emission colors for each pixel. In FIG. A red organic light emitting layer (29a), a green organic light emitting layer (29b), and a blue organic light emitting layer (29c). Polyparaphenylene vinylene (PPV), polyfluorene (PF), etc. can be used as the organic light emitting layer forming material. These organic light-emitting materials are dissolved in an aromatic organic solvent such as toluene to form ink, and are patterned into three colors by using a printing method.

  As a printing method, an ink jet printing method, an offset printing method, a letterpress printing method, or the like can be used, and among these, a letterpress reverse printing method can be preferably used. FIG. 6 shows a schematic diagram of the printing process in the letterpress reverse offset printing method.

  In FIG. 6, a blanket (39) is mounted around the blanket cylinder (38) on the main body frame (37). Reference numeral (40) denotes a printing stage, which fixes the relief plate (41) and the substrate to be printed (43), which are the original plates, during printing. The printing stage (40) is movable in the uniaxial direction on the main body frame (37). In addition, (42) shown in the figure is ink. A first electrode, a partition, and a hole transport layer are formed in advance on the substrate to be printed.

  The letterpress (41) is fixed on the printing stage (40), and the ink (42) is previously applied to the blanket (39) by an ink supply means (not shown), curtain coating method, bar coating method, wire coating method, slitting. It is applied using a coating such as a coating method (FIG. 6A). By moving the printing stage (40) and rotating the blanket cylinder, the ink film on the blanket (39) is removed by the relief pattern (41) which is the negative pattern of the desired pattern, and the ink on the blanket is changed to the desired pattern. Patterning is performed (FIG. 6B). Next, the printing stage (40) is moved and the blanket cylinder is rotated, whereby the ink pattern on the blanket is transferred onto the substrate (43) to be printed, and the printing process is completed (FIGS. 6C and 6D). )).

  The letterpress reverse offset printing apparatus is a system in which the blank cylinder is fixed and the stage including the letterpress and the substrate to be printed moves, but the letterpress reverse offset printing apparatus of the present invention is fixed at the stage during printing. It may be a system in which the bran cylinder moves.

  The printing blanket in the present invention is preferably composed of a material having a certain degree of flexibility such as a polymer film or rubber, and silicone rubber can be used.

  As another suitable printing method, a relief printing method can be adopted. It shows about the manufacturing method of the printed matter which forms an ink pattern on the to-be-printed substrate surface by a relief printing method. FIG. 7 shows a schematic diagram of a relief printing apparatus used for manufacturing the printed matter of the present invention. The printing substrate 106 is fixed to the stage 107, the printing relief plate 104 is fixed to the plate cylinder 105, the printing relief plate 104 is in contact with the anilox roll 103 which is an ink supply body, and the anilox roll 103 is replenished with ink. A device 101 and a doctor 102 are provided.

First, ink is replenished from the ink replenishing device 101 to the anilox roll 103, and excess ink out of the ink 108 supplied to the anilox roll 103 is removed by the doctor 102. The ink replenishing device 101 may be a dripping type ink replenishing device, a fountain roll, a slit coater, a die coater, a cap coater such as a cap coater, or a combination thereof. For the doctor 102, a known object such as a doctor roll can be used in addition to the doctor blade. Further, the anilox roll 103 can be made of chromium or ceramics. Further, it is also possible to use a lithographic anilox plate instead of a cylindrical anilox roll as an ink supply to the printing relief plate. The planographic anilox plate is disposed, for example, at the position of the printing substrate 106 in FIG. 7. After the ink is replenished to the entire surface of the anilox plate by the ink replenishing device, the ink is supplied to the printing substrate by rotating the plate cylinder. Can be done.

  The ink uniformly held by the doctor on the surface of the anilox roll 103 which is an ink supply body to the printing relief plate is transferred and supplied to the projection pattern of the printing relief plate 104 attached to the plate cylinder 105. Then, as the plate cylinder 105 rotates, the convex pattern of the printing relief plate 104 and the substrate move relatively while in contact with each other, and the ink 108 is transferred to a predetermined position on the printing substrate 106 on the stage 107 to be printed substrate. An ink pattern 108a is formed on the substrate. After the ink pattern is provided on the substrate to be printed, a drying step using an oven or the like can be provided as necessary.

  When printing the ink on the printing relief plate on the printing substrate, the stage 17 to which the printing substrate 106 is fixed may be moved in accordance with the rotation of the plate cylinder 105. FIG. A printing unit including the upper plate cylinder 105, the printing relief plate 104, the anilox roll 103, and the ink replenishing device 101 may be moved in accordance with the rotation of the plate cylinder. In the printing relief plate of the present invention, a resin layer may be formed on the plate cylinder 15 and directly plate-making to form a projection pattern.

  FIG. 7 shows a sheet-type relief printing apparatus that forms an ink pattern on a substrate to be printed one by one. However, in the method for producing printed matter of the present invention, the substrate to be printed can be wound in a web shape. In some cases, a roll-to-roll relief printing apparatus can be used. When a roll-to-roll type letterpress printing apparatus is used, it is possible to continuously form an ink pattern and to reduce the manufacturing cost.

  Next, an electron injecting protective layer (32) is provided on the organic light emitting layers (29a, 29b, 29c). As a material for forming an electron injecting protective layer, rare earth elements having a low work function such as Ca and Ba can be used, and these rare earth elements are formed by vacuum deposition to form an electron injecting protective layer.

  Next, a transparent electrode (33) is provided as a cathode on the electron injecting protective layer (32). In forming the transparent electrode, the transparent conductive film forming method of the present invention described above can be used. In the top emission type organic electroluminescent device, the transparent conductive film forming method of the present invention can be suitably used when forming a transparent electrode. Since the transparent conductive film forming method of the present invention can reduce damage to an organic thin film such as an organic light emitting layer when forming a film by sputtering, an organic electroluminescent device having excellent light emitting characteristics can be obtained. . Further, the transparent conductive film forming method of the present invention can suppress the temperature rise of the patterning mask during film formation. Therefore, thermal expansion and thermal deformation of the mask can be suppressed, and the transparent electrode can be accurately patterned. In the organic electroluminescent element of the present invention, the reflective electrode may be a cathode and the transparent electrode may be an anode.

  Next, a reflective electrode (26), a partition wall (27), a hole transport layer (28), an organic light emitting layer (29a, 29b, 29c), an electron injecting protective layer (32), and a transparent electrode (33) are formed. Sealing is performed on the substrate (25). First, a barrier layer (34) is formed on the entire substrate (25).

As the barrier layer (34), a silicon nitride film, a silicon oxide film, a silicon nitride oxide film, or the like can be used. The barrier film is formed by a CVD method. In the CVD method, a vaporized compound (source gas) containing the element to be filmed is mixed as it is or mixed with a carrier gas such as hydrogen or nitrogen, and is sent as uniformly as possible to the substrate surface heated at high temperature. In this method, a thin film is formed on a substrate by causing a chemical reaction such as reduction, oxidation, or substitution.

  Furthermore, the base material provided with the barrier layer (34) is bonded to the sealing substrate (36) through the resin layer (35). As a sealing substrate (36), what is necessary is just to have transparency, Glass and plastic materials, such as non-alkali glass and alkali glass, can be used. Or you may bond both together by making the base material which formed CaO in the said glass into a sealing base material. Thereby, it is possible to perform sealing without inserting a desiccant. In addition, since the glass is directly bonded to the upper part of the base material, the light absorption at the sealing base material and the change in the optical path length that occurs when using a glass with a cap structure do not occur, and the light extraction efficiency is improved. You can also. As the resin layer (35), a photo-curing adhesive resin, a thermosetting adhesive resin, a two-component curable adhesive resin made of an epoxy resin, an acrylic resin, a silicone resin, or the like, or ethylene ethyl acrylate (EEA) Examples thereof include acrylic resins such as polymers, vinyl resins such as ethylene vinyl acetate (EVA), thermoplastic resins such as polyamide and synthetic rubber, and thermoplastic adhesive resins such as acid-modified products of polyethylene and polypropylene.

  As a bonding method, a method by pressure bonding with a heated roll can be used. Moreover, when using a photocurable adhesive resin as a resin layer, it can bond together by irradiating with ultraviolet light.

  Moreover, in the organic electroluminescent element of this invention, it can be set as a flexible organic electroluminescent element by using a flexible plastic base material for a base material and a sealing base material.

  Moreover, in the organic electroluminescent element of this invention, it can be set as a transparent organic electroluminescent element by making both electrodes into a transparent electrode, making a base material into a transparent base material, and sealing with a transparent material. FIG. 5 shows an explanatory cross-sectional view of the transparent organic electroluminescent element. In FIG. 5, a transparent electrode (26) is formed as a first electrode on a transparent substrate (25), and as in FIG. 4, a partition wall (27), a hole transport layer (28), an organic light emitting layer (29a) 29b, 29c), an electron injecting protective layer (32), and a transparent electrode (33). Furthermore, it is sealed with a barrier layer (34) having transparency, a resin layer (35), and a sealing substrate (36). In the transparent organic electroluminescent element, it is possible to display images from both the substrate side and the opposite side of the substrate.

  A glass substrate was used as a substrate, Cr was formed on the substrate as a reflective electrode as an anode, and ITO was laminated as an anode interface layer by a sputtering method. The laminated film of Cr and ITO on the obtained substrate was patterned by a photolithographic method to obtain a stripe pattern. Next, a partition wall was formed by a photolithography method using a polyimide material so as to cover the end portion of the striped Cr. Next, PEDOT / PSS was used as a hole transport material, which was dissolved in water to form a coating solution, and a hole transport layer was formed by a spin coating method.

  Next, using a green organic light emitting material made of polyfluorene (PF), this green organic light emitting material was dissolved in toluene to form an ink, and an organic light emitting layer was formed in stripes by letterpress reverse printing. Next, an electron injecting protective layer made of Ca and Al was formed on the organic light emitting layer by vapor deposition using a mask so as to be orthogonal to the Cr stripe pattern of the anode.

Next, a transparent electrode was formed using the transparent conductive film forming method of the present invention. As the sputtering apparatus, a DC magnetron sputtering apparatus was used. At this time, in the DC magnetron sputtering apparatus, a stainless steel circular trap having a pin made of a magnet is provided between the substrate and the target, and a mask is provided so as to contact the substrate, and the mask is fixed by a magnet holder. . In addition, a Peltier element was provided on the side of the substrate opposite to the transparent electrode film forming surface. The sputtering conditions are a gas pressure of 1.0 Pa, a gas flow rate ratio of Ar / O ₂ = 100 / 1.0, a discharge power density of 0.21 W / cm ² , and a target-substrate distance of 130 mm. At this time, the transparent electrode ITO was provided so as to have a film thickness of 150 nm so as to overlap the electron injecting protective layer and to be orthogonal to the Cr stripe pattern as the reflective electrode. The mask temperature during sputtering film formation was 50 ° C.

  Next, sealing was performed by providing a silicon oxide film over the entire light emitting region of the organic electroluminescent element by a CVD method and further bonding it to a glass substrate through a CaO film to obtain a top emission type organic electroluminescent element.

Regarding the device characteristics of the obtained organic electroluminescence device, the maximum luminance is 2000 cdm ⁻² and the maximum current efficiency is 2.2 cdA ⁻¹ .
(Comparative example)
As in the example, a transparent electrode was formed on a glass substrate on which a reflective electrode, a partition, a hole transport layer, an organic light emitting layer, and an electron injecting protective layer were formed using a DC magnetron sputtering apparatus as in the example. went. However, in the DC magnetron sputtering apparatus, a circular trap was not provided between the target and the substrate. Further, no Peltier element was provided on the substrate. In the sputtering, other sputtering conditions are the same as those in the examples.

At this time, the mask temperature during sputtering was 60 ° C., which was higher by about 10 ° C. than Example 1. Moreover, sealing was performed on the substrate on which the transparent electrode was formed in the same manner as in the example to obtain an organic electroluminescent element. The resulting organic electroluminescence device had a maximum luminance of 200 cdm ⁻² and a maximum current efficiency of 0.05 cdA ⁻¹ .

FIG. 1 is a schematic view of a DC magnetron sputtering apparatus used for forming a transparent conductive film of the present invention. FIG. 2 is an explanatory view of the periphery of the substrate in the transparent conductive film forming method of the present invention. FIG. 3 is an explanatory sectional view of the Peltier element. FIG. 4 is an explanatory sectional view of a top emission type organic electroluminescence device. FIG. 5 is an explanatory cross-sectional view of a transparent organic electroluminescent element. FIG. 6 is a schematic diagram of a printing process by the letterpress reverse offset printing method of the present invention. FIG. 7 is a schematic diagram of a printing process by the relief printing method of the present invention.

Explanation of symbols

1 Substrate 2 Trap electrode 3 Magnet pin 4 Two-point polarity switching mechanism (trap)
5 Plasma 6 γ Electron 7 Ar Ion 8 Magnetic Field Line 9 Electron Capture Orbit (Larmor Radius)
10 Target 11 Backing plate (OFC)
12 Cathode magnet 13 Chiller 14 Ground 15 Peltier element 16 Magnet holder 17 Mask 17a Mask opening 19 Mask frame 20 Lead wire 21 Ceramic substrate 22 Metal electrode 23a P-type semiconductor 23b N-type semiconductor 25 Base material 26 Reflective electrode (first electrode) )
27 Partition 28 Hole transport layer 29a Red (R) organic light emitting layer 29b Green (G) organic light emitting layer 29c Blue (B) organic light emitting layer 32 Electron injecting protective layer 33 Transparent electrode (second electrode)
34 Barrier layer 35 Resin layer 36 Sealing substrate 37 Main body frame 38 Blank cylinder 39 Blanket 40 Printing stage 41 Intaglio plate 42 Ink 43 Transfer substrate L Light emission 101 Ink replenishing device 102 Doctor 103 Anilox roll 104 Printing relief plate 105 Printing cylinder 106 Covered object Printed circuit board 107 Stage 108 Ink 108a Ink pattern

Claims (9)

  In a transparent conductive film forming method in which a mask is provided on a substrate and a transparent conductive film is patterned on the substrate by a sputtering method, a trap electrode having a pin made of a magnet is provided between the target and the substrate, and the substrate is formed by sputtering. A method of forming a transparent conductive film comprising patterning a transparent conductive film made of a target forming material.   The magnet has a conical shape, a plurality of the magnets are arranged in a circle around the outer periphery of the trap electrode, and the polarity of the magnet is oriented so that the lines of magnetic force are stretched around the trap electrode surface. The method for forming a transparent conductive film according to claim 1.   By applying a voltage to the trap electrode with a magnet, the charged particles are attracted to the tip of the magnet by electrostatic attraction, neutralizing the polarity of the charged particles, or magnetic lines of force oriented to stretch around the trap electrode surface. The method for forming a transparent conductive film according to claim 2, wherein plasma charged particles are attracted to the surface.   4. The method for forming a transparent conductive film according to claim 1, wherein the substrate is cooled by a Peltier element during the formation of the transparent conductive film.   In the method of manufacturing an organic electroluminescent element, the first electrode, the organic light emitting layer, and the second electrode are provided on the base material at least in this order, and the organic light emitting layer emits light by passing a current between the electrodes. A method for producing an organic electroluminescent element, wherein at least one of the electrodes is patterned by the method according to claim 1.   In the method of manufacturing a top emission type organic electroluminescence device, a transparent electrode is provided in a manufacturing method of a top emission type organic electroluminescence device comprising a reflective electrode, an organic light emitting layer, and a transparent electrode on a substrate in this order, and causing the organic light emitting layer to emit light by passing a current between the electrodes A method for producing a top emission type organic electroluminescence device, which is formed by the method according to any one of 1 to 4.   The method for producing an organic electroluminescent element according to claim 5 or 6, wherein the organic light-emitting layer forming material is dissolved or dispersed in a solvent to form an ink, and the ink is used for reversal offset printing using the relief printing method. A method for producing an organic electroluminescent device comprising a step of forming an organic light emitting layer on a material.   The method for producing an organic electroluminescent element according to claim 5 or 6, wherein the organic light emitting layer forming material is dissolved or dispersed in a solvent to form an ink, and the ink is used on the substrate by a relief printing method. And a method of forming an organic light emitting layer.   In the manufacturing method of the organic electroluminescent element of Claim 5 or Claim 6 or Claim 7 or Claim 8, the base material which formed CaO on glass on the base material in which the said organic light emitting layer and the electrode were formed. A method for producing an organic electroluminescent element, wherein both are bonded together as a sealing substrate.