JP2010089447A - Transfer donor substrate, and device manufacturing method for device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transfer donor substrate which enables a large-sized and highly precise fine patterning and by which the degradation of donor substrate and deterioration of performance capacity of a device substrate can be prevented, and to provide a manufacturing method for the device such as an organic EL device using the donor substrate. <P>SOLUTION: The transfer donor substrate includes, a support, a photothermal conversion layer formed on the support, a partition pattern formed on the photothermal conversion layer, and a transfer material formed in the partition pattern. The partition pattern is thicker than the average thickness of the transfer material. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a donor substrate for transfer used for patterning a device including an organic EL element, and a device manufacturing method using the same.

  An organic EL element emits light by recombining electrons injected from a cathode and holes injected from an anode in an organic material light emitting layer sandwiched between both electrodes. The organic EL element that emits light as described above has been thin and capable of high luminance under a low driving voltage since the research results shown in Non-Patent Document 1 have been shown, and various organic materials can be used for the light emitting layer. By using, it is possible to obtain various emission colors including the three primary colors of red (R), green (G), and blue (B). As a result, various technologies have been required. One of them is a technique for forming a light emitting layer which is a thin film having a film thickness of 0.1 μm or less and finely patterned for each of the three primary colors on a device substrate on which an organic EL element is formed as a final product.

  Conventionally, wet processes such as photolithographic method, ink jet method, and printing method have been used for fine patterning of thin films. However, when photoresist or ink is applied on the previously formed underlayer, It has been difficult to completely prevent morphological changes and unwanted mixing, and it has been difficult to achieve film thickness uniformity of a thin film dried from a wet state. In contrast, several types of dry processes have been put into practical use or proposed. Among them, the mask vapor deposition method is to attach a vapor deposition mask with precise holes on a metal plate and use it as a mask to deposit each luminescent material on the device substrate. It is difficult to achieve both, and the adhesion between the device substrate and the vapor deposition asks tends to be lost as the size increases.

  As a dry process corresponding to the increase in size of color displays, RGB light emitting materials are once applied to a transfer donor sheet (donor film or donor substrate) to form a finely patterned transfer material, and the transfer material is used as a device. Some have been developed for vapor deposition transfer onto a substrate. For example, Patent Document 1 describes one in which a transfer material is transferred to a device substrate by heating the entire donor sheet. Patent Document 2 describes a technique in which a transfer material partitioned by partition walls (partition pattern) patterned on a donor sheet is formed, and the transfer material is transferred to a device substrate by heating the entire donor sheet. . However, in the methods described in Patent Documents 1 and 2, the entire donor sheet is thermally expanded by heating and the relative position of the transfer material formed on the device substrate is displaced. As a result, it has been difficult to obtain a highly accurate fine pattern on the device substrate. Furthermore, there is also a problem that the device performance is deteriorated due to the device substrate being heated by radiation from the donor sheet. Moreover, when there is a partition (partition pattern) like patent document 2, there also existed a problem that device performance deteriorated by the influence of the degassing by the heating.

In Patent Documents 3 and 4, a photothermal conversion layer laminated on a transfer material is provided on a donor sheet, and a laser is irradiated from behind the photothermal conversion layer to generate heat locally, thereby forming a thin film material for each pixel device substrate. Is described in what is transferred. In Patent Document 3, a donor sheet for each RGB is prepared, and in Patent Document 4, RGB is separately applied to one donor sheet in a stripe shape. In Patent Document 5, a transfer material partitioned by a separator (partition pattern) patterned on a donor sheet is formed, and a thin film material is transferred to a device substrate by scanning the laser to generate heat locally. What to do is described. In the method of partially irradiating the lasers described in Patent Documents 3 to 5, the entire donor sheet is not heated. Therefore, the displacement of the donor sheet as described in Patent Documents 1 and 2 basically does not occur, and the device substrate is the donor sheet. It is also suppressed that the device performance is deteriorated by being heated by radiation from the device. Further, since the separator (partition pattern) of Patent Document 5 is not irradiated with laser, the device performance is not basically deteriorated by the influence of degassing.
“Applied Physics Letters”, (USA), 1987, 51, 12, 913-915. JP 2002-260854 A JP 2000-195665 A Japanese Patent No. 3789991 JP 2005-149823 A JP 2004-87143 A

  As described above, the method of transferring the transfer material by partially irradiating the laser is an effective technique for achieving both the enlargement and the highly accurate miniaturization. However, those described in Patent Documents 3 and 4 are not easy to accurately determine the laser intensity and irradiation time in consideration of the lateral diffusion of the generated heat, and have put this technology to practical use. In some cases, there is an increased probability that the transfer material will deteriorate above the decomposition temperature. In the case of Patent Document 5, since the transfer material is thin, the laser is not sufficiently absorbed and reaches the device substrate to deteriorate the underlayer, or the separator (partition pattern) is irradiated with the laser. Sometimes, the separator deteriorates or the device performance of the device substrate deteriorates due to degassing.

  The present invention has been made in view of the above-mentioned reasons, and an object of the present invention is a donor substrate that transfers a transfer material onto a device substrate by irradiating light typified by a laser, and has a large size and high accuracy. An object of the present invention is to provide a donor substrate that can be patterned and prevents deterioration of the donor substrate and device performance of the device substrate. Moreover, it is providing the method of manufacturing an organic EL element using this donor substrate.

  To achieve the above object, a donor substrate for transfer according to the present invention comprises a support, a photothermal conversion layer formed on the support, a partition pattern formed by laminating the photothermal conversion layer, and the partition And a transfer material formed in the pattern, wherein the partition pattern has a thickness greater than an average film thickness of the transfer material.

  According to the donor substrate for transfer of the present invention, it is possible to perform fine patterning with high accuracy even in a large size by irradiating and transferring light onto a partition pattern thicker than the average film thickness of the transfer material simultaneously with the transfer material. In addition, it is possible to prevent adverse effects on the device performance due to deterioration of the donor substrate such as the transfer material and the partition pattern, degassing from the partition pattern, and high temperature. When this donor substrate is used, it is possible to manufacture a large organic EL element finely patterned with high accuracy without deteriorating device performance.

The best mode for carrying out the present invention will be described below with reference to the drawings. Note that the enlarged sectional view and the enlarged plan view used in this specification show RGB sub-pixels constituting a pixel which is a minimum unit of a color display. Further, in order to help understanding, the magnification in the vertical direction (perpendicular to the substrate surface) is enlarged as compared with the horizontal direction (substrate surface direction) in the enlarged cross-sectional view. Hereinafter, a device substrate 10 having a typical structure on which an organic EL element is formed will be described, and then a donor substrate 30 according to an embodiment of the present invention suitable for forming an organic EL element on the device substrate 10 by transfer is described. Next, a method for manufacturing an organic EL element will be described focusing on a transfer process using the donor substrate 30.
(1) Device substrate 10
FIG. 1 is an enlarged cross-sectional view showing an example of a typical structure of a device substrate 10 on which an organic EL element is formed. In the device substrate 10, an active matrix circuit composed of TFTs 12 (including extraction electrodes), a planarizing layer 13, and the like is formed on a support 11 such as a glass plate. A first electrode 15 / hole transporting layer 16 / light emitting layer 17 / electron transporting layer 18 / second electrode 19 constituting the organic EL element are formed thereon. In the example of FIG. 1, the light emitting layer 17 is composed of three types of RGB light emitting layers 17R, 17G, and 17B, which are partitioned in the horizontal direction. At the end of the first electrode 15, an insulating layer 14 that prevents a short circuit from occurring at the electrode end and defines a light emitting region is formed. The element configuration of the organic EL element is not limited to this example. For example, only one light emitting layer 17 having a hole transport function and an electron transport function is provided between the first electrode 15 and the second electrode 19. The hole transport layer 16 may be formed of a hole injection layer and a hole transport layer, the electron transport layer 18 may be a multilayer structure of an electron transport layer and an electron injection layer, When the light emitting layer 17 has an electron transport function, the electron transport layer 18 may be omitted. Alternatively, the first electrode 15 / electron transport layer 18 / light emitting layer 17 / hole transport layer 16 / second electrode 19 may be laminated in this order. In addition, these layers may be a single layer or a plurality of layers. Although not shown in the figure, after the second electrode 19 is formed, a protective layer, a color filter, sealing, or the like may be performed using a known technique or a transfer process of this embodiment described later. .

  The light emitting layer 17 may be a single layer or a plurality of layers, and the light emitting material of each layer may be a single material or a mixture of a plurality of materials. From the viewpoint of luminous efficiency, color purity, and durability, the light emitting layer 17 preferably has a single layer structure of a mixture of a host material and a dopant material.

Examples of the light-emitting material of the light-emitting layer 17 include anthracene derivatives, naphthacene derivatives, pyrene derivatives, quinolinol complexes such as tris (8-quinolinolato) aluminum (Alq ₃ ), various metal complexes such as benzothiazolylphenol zinc complexes, and bisstyrylanthracene. Derivatives, tetraphenylbutadiene derivatives, coumarin derivatives, oxadiazole derivatives, benzoxazole derivatives, carbazole derivatives, distyrylbenzene derivatives, pyrrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, oxadiazole derivatives, thiadiazolopyridine derivatives, rubrene , Quinacridone derivatives, phenoxazone derivatives, perinone derivatives, perylene derivatives, coumarin derivatives, chrysene derivatives, pyromethene derivatives, iridium called phosphorescent materials Low molecular weight material or the like arm complex materials, polyphenylene vinylene derivatives, polyparaphenylene derivatives, can be exemplified a polymer material such as a polythiophene derivative. In particular, examples of materials excellent in light emission performance and suitable for this embodiment include anthracene derivatives, naphthacene derivatives, pyrene derivatives, chrysene derivatives, pyromethene derivatives, and various phosphorescent materials.

  The hole transport layer 16 may be a single layer or a plurality of layers, and each layer may be a single material or a mixture of a plurality of materials. A layer called a hole injection layer is also included in the hole transport layer 16. From the viewpoint of hole transportability (low driving voltage) and durability, the hole transport layer 16 may be mixed with an acceptor material that promotes hole transportability.

  As a hole transport material of the hole transport layer 16, N, N′-diphenyl-N, N′-dinaphthyl-1,1′-diphenyl-4,4′-diamine (NPD) or N, N′-biphenyl is used. -N, N'-biphenyl-1,1'-diphenyl-4,4'-diamine, N, N'-diphenyl-N, N '-(N-phenylcarbazolyl) -1,1'-diphenyl- Low molecular weight compounds such as aromatic amines represented by 4,4′-diamine, N-isopropylcarbazole, pyrazoline derivatives, stilbene compounds, hydrazone compounds, oxadiazole derivatives and heterocyclic compounds represented by phthalocyanine derivatives Examples thereof include polymer materials such as polycarbonate, styrene derivatives, polyvinyl carbazole, and polysilane having these low molecular compounds in the side chain. Examples of the acceptor material include low molecular weight materials such as 7,7,8,8-tetracyanoquinodimethane (TCNQ), hexaazatriphenylene (HAT) and its cyano group derivative (HAT-CN6). Further, metal oxides such as molybdenum oxide and silicon oxide that are thinly formed on the surface of the first electrode 15 can also be exemplified as hole transport materials and acceptor materials.

  The electron transport layer 18 may be a single layer or a plurality of layers, and each layer may be a single material or a mixture of a plurality of materials. A layer called a hole blocking layer or an electron injection layer is also included in the electron transport layer 18. From the viewpoint of electron transport properties (low driving voltage) and durability, the electron transport layer 18 may be mixed with a donor material that promotes electron transport properties. A layer called the electron injection layer is often discussed as this donor material. The transfer material for forming the electron transport layer 18 may be made of a single material or a mixture of a plurality of materials.

Examples of the electron transport material for the electron transport layer 18 include quinolinol complexes such as Alq ₃ and 8-quinolinolatolithium (Liq), condensed polycyclic aromatic derivatives such as naphthalene and anthracene, 4,4′-bis (diphenylethenyl). ) Stylyl aromatic ring derivatives represented by biphenyl, quinone derivatives such as anthraquinone and diphenoquinone, phosphorus oxide derivatives, benzoquinolinol complexes, hydroxyazole complexes, azomethine complexes, tropolone metal complexes, flavonol metal complexes, and other metal complexes, electron acceptance Examples include low molecular materials such as compounds having a heteroaryl ring structure containing reactive nitrogen, and polymer materials having these low molecular compounds in the side chain.

  Examples of the donor material include alkali metals and alkaline earth metals such as lithium, cesium, magnesium, and calcium, various metal complexes such as quinolinol complexes, and oxides and fluorides such as lithium fluoride and cesium oxide. be able to. An electron transport material or a donor material is one of the materials in which performance changes easily occur in combination with the light emitting layer 17.

  It is preferable that at least one of the first electrode 15 and the second electrode 19 is transparent in order to extract light emitted from the light emitting layer 17. In the case of bottom emission in which light is extracted from the first electrode 15, the first electrode 15 is transparent, and in the case of top emission in which light is extracted from the second electrode 19, the second electrode 19 is transparent. As the transparent electrode material and the other electrode, conventionally known materials can be used as described in JP-A-11-214154, for example.

Such an organic EL element is not generally limited to an active matrix type in which the second electrode 19 is formed as a common electrode. For example, a stripe in which the first electrode 15 and the second electrode 19 intersect each other is used. It may be a simple matrix type composed of electrode-like electrodes, or a segment type in which the display unit is patterned so as to display predetermined information. Examples of these applications include televisions, personal computers, monitors, watches, thermometers, audio equipment, automobile display panels, and the like.
(2) Donor substrate 30
Next, a donor substrate 30 according to an embodiment of the present invention suitable for forming an organic EL element on the device substrate 10 by transfer will be described. 2 and 3 are an enlarged cross-sectional view and an enlarged plan view showing an example of a method for forming the light emitting layer 17 on the device substrate 10 using the donor substrate 30. FIG. The donor substrate 30 is partitioned by a support 31, a photothermal conversion layer 33 formed on the support 31, a partition pattern 34 formed by being laminated on the photothermal conversion layer 33, and a partition pattern 34, and a transfer material 37. And comprising. 2 and 3, the transfer material 37 of the donor substrate 30 includes transfer materials 37R, 37G, and 37B of three kinds of light emitting materials of RGB divided in the horizontal direction. It corresponds to the types of light emitting layers 17R, 17G, and 17B. 3 is a view of the state of light irradiation in FIG. 2 as viewed from the support 31 side of the donor substrate 30. FIG. Since there is the photothermal conversion layer 33 formed on the entire surface, the partition pattern 34 and the transfer materials 37R, 37G, and 37B are not actually visible from the support 31 side, but a dotted line is used to explain the positional relationship with light irradiation. This is illustrated in FIG. The irradiated light has a rectangular shape, is irradiated so as to straddle the transfer materials 37R, 37G, and 37B, and is scanned in a direction perpendicular to the arrangement of the transfer materials 37R, 37G, and 37B. The irradiated light may be scanned relatively, and the light itself may be moved, the set of the donor substrate 30 and the device substrate 10 may be moved, or both. Hereinafter, the support 31, the photothermal conversion layer 33, the transfer material 37, and the partition pattern 34 will be described in this order.

  The support 31 of the donor substrate 30 is not particularly limited as long as it has a low light absorption rate and can stably form the photothermal conversion layer 33, the partition pattern 34, and the transfer material 37 thereon. Depending on the conditions, it is possible to use a film of a resin material. Polyester, polyethylene, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyacryl, polysulfone, polyethersulfone, polyphenylene sulfide, polyimide, polyamide, polybenzoxazole, polyepoxy, polypropylene, polyolefin, aramid resin, silicone Resin etc. can be illustrated.

  In terms of chemical / thermal stability, dimensional stability, mechanical strength, and transparency, a preferable support 31 may be a glass plate. Soda lime glass, alkali-free glass, lead-containing glass, borosilicate glass, aluminosilicate glass, low expansion glass, quartz glass and the like can be selected according to the conditions. As will be described later, when the transfer process is performed in a vacuum, since it is required that the gas release from the support 31 is small, a glass plate is particularly preferable also in this respect.

  When transferring the transfer material with the device substrate 10 and the donor substrate 30 facing each other, in order to prevent the patterning accuracy from deteriorating due to a difference in thermal expansion due to a temperature change, the support 11 of the device substrate 10 and the donor substrate 30, The difference in thermal expansion coefficient between 31 is preferably 10 ppm / ° C. or less, and it is more preferable that these supports 11 and 31 are made of the same material. The difference in thickness between the two is not particularly limited.

  Even if the photothermal conversion layer 33 is heated to a high temperature, the temperature rise (thermal expansion) of the support 31 itself needs to be within an allowable range, so that the heat capacity of the support 31 is sufficiently larger than that of the photothermal conversion layer 33. Is preferred. Accordingly, the thickness of the support 31 is preferably 10 times or more the thickness of the photothermal conversion layer 33. The allowable range depends on the size of the transfer region, the required accuracy of patterning, and the like. However, for example, the photothermal conversion layer 33 rises by 300 ° C. from room temperature, and the temperature rise of the support 31 is reduced to 1/100 of that. When it is desired to suppress the temperature to 3 ° C. or less, the thickness of the support 31 is preferably 100 times or more the thickness of the photothermal conversion layer 33, and the temperature rise of the support 31 is 1/300 of 300 ° C. When it is desired to suppress the temperature below 1 ° C., the thickness of the support 31 is more preferably 300 times or more the thickness of the photothermal conversion layer 33. By doing in this way, even if it enlarges, the amount of dimensional displacement by thermal expansion is small, and it contributes to highly accurate fine patterning.

  Next, the photothermal conversion layer 33 of the donor substrate 30 will be described. The photothermal conversion layer 33 is not particularly limited as long as it is a material and configuration that efficiently absorbs light to generate heat and is stable against the generated heat. A thin film in which carbon black, graphite, titanium black, organic pigments, metal particles, or the like are dispersed in a resin can be used. As will be described later, since the photothermal conversion layer 33 may be heated to about 300 ° C., the photothermal conversion layer 33 is preferably made of an inorganic thin film having excellent heat resistance. It is particularly preferable that the thin film is made of a material. Examples of metal materials include tungsten, tantalum, molybdenum, titanium, chromium, gold, silver, copper, platinum, iron, zinc, aluminum, cobalt, nickel, magnesium, vanadium, zirconium, silicon, carbon, etc. Can be used.

  If necessary, an antireflection layer can be formed on the support 31 side of the photothermal conversion layer 33. Further, an antireflection layer may be formed on the surface of the support 31 on the light incident side. These anti-reflection layers are preferably optical interference thin films that use the difference in refractive index, and simple or mixed thin films such as silicon, silicon oxide, silicon nitride, zinc oxide, magnesium oxide, and titanium oxide, and laminated thin films thereof are used. it can.

  A transfer auxiliary layer 39 can be formed on the photothermal conversion layer 33 on the transfer material 37 side, if necessary. An example of the function of the transfer auxiliary layer 39 is a function of preventing the transfer material from being deteriorated by the catalytic effect of the heated light-to-heat conversion layer 33, and is inactive such as tungsten, tantalum, molybdenum, silicon, oxide, and nitride. Inorganic thin films can be used. Another example of the function of the transfer auxiliary layer 39 is a surface modification function when the transfer material 37 is formed by a coating method, which will be described later. The illustrated rough surface thin film of an inert inorganic thin film or porous metal oxide. A membrane or the like can be used. Another example of the function of the transfer auxiliary layer 39 is to make the transfer material 37 uniform by heating. For example, as shown in FIG. 4A, in order to uniformly heat the relatively thick transfer material 37, heat conduction is performed. The transfer auxiliary layer 39 having a spike-like (or porous) structure can be formed from a material such as a metal having excellent properties, and the transfer material 37 can be arranged to be carried in the gap. The transfer auxiliary layer 39 having this function may be integrated with the photothermal conversion layer 33 as shown in FIG.

  Since the light-to-heat conversion layer 33 needs to give sufficient heat to the evaporation of the transfer material of the transfer material 37, the heat capacity of the light-to-heat conversion layer 33 is preferably larger than that of the transfer material 37. Therefore, the thickness of the photothermal conversion layer 33 is preferably thicker than the transfer material 37, and more preferably 5 times or more the thickness of the transfer material 37. The numerical value is preferably 0.02 to 2 μm, more preferably 0.1 to 1 μm. Since the photothermal conversion layer 33 preferably absorbs 90% or more of light, and more preferably 95% or more, the thickness of the photothermal conversion layer 33 is preferably designed so as to satisfy these conditions. The transfer auxiliary layer 39 is preferably designed to be thin within a range that satisfies the required function so as not to prevent the heat generated in the light-to-heat conversion layer 33 from being efficiently transferred to the transfer material 37.

  If the photothermal conversion layer 33 is formed in a portion where the transfer material 37 is present, the planar shape is not particularly limited. For example, even if the photothermal conversion layer 33 is formed on the entire surface of the donor substrate 30 as illustrated above, for example, a partition pattern 34. It may be patterned so as to be discontinuous at the bottom of the substrate. When the partition pattern 34 has poor adhesion to the photothermal conversion layer 33, the adhesion can be improved by utilizing the adhesion to the support 31 in this manner. When the photothermal conversion layer 33 is patterned, it is not necessary to have the same type of shape as the partition pattern 34, the partition pattern 34 may be a lattice shape, and the photothermal conversion layer 33 may be a stripe shape. Since the photothermal conversion layer 33 has a high light absorptance, it is preferable to use the photothermal conversion layer 33 to form position marks on the donor substrate 30 at appropriate positions inside and outside the transfer region.

  As a method for forming the photothermal conversion layer 33 and the transfer auxiliary layer 39, a known technique such as spin coating, slit coating, vacuum deposition, EB deposition, sputtering, or ion plating can be used. When patterning, a known photolithography method, laser ablation, or the like can be used.

  Next, the transfer material 37 of the donor substrate 30 will be described. As the transfer material of the transfer material 37, either an organic material or an inorganic material containing a metal is evaporated, sublimated, or ablated when heated, or a donor substrate is used by utilizing an adhesive change or a volume change. May be transferred to the device substrate 10. The transfer material may be a precursor for thin film formation, and the transfer film 27 may be formed by being converted into a thin film formation material by heat or light before or during transfer. This transfer material can form not only organic EL elements but also thin films constituting devices such as organic TFTs, photoelectric conversion elements, and various sensors.

  As described below, the vapor deposition mode is preferable for the transfer, and even if the entire film thickness of the transfer material 37 is transferred by one light irradiation, the film thickness of the transfer material 37 is divided into a plurality of times by a plurality of light irradiations. May be. Further, by using the peeling mode or the ablation mode, for example, when the electron transport layer 18 / light emitting layer 17 is formed on the device substrate 10 as a transfer film, the electron transport layer / light emitting layer of the transfer material on the donor substrate 30 is used. By forming a laminated structure and transferring it to the device substrate 10 while maintaining the laminated state, the transfer film of the light emitting layer 17 / electron transporting layer 18 can be patterned once.

  It is difficult to indicate the thickness of the transfer material 37 in general according to the functions and the number of transfers. For example, the transfer material 37 for one transfer of a donor material (electron injection material) such as lithium fluoride has a typical thickness of 1 nm or less. In addition, the thickness of the transfer material 37 of the electrode material may be 100 nm or more. In the case of forming the light emitting layer 17, the thickness of the transfer material 37 for one transfer is preferably 10 to 100 nm, and more preferably 20 to 50 nm.

  A method for forming the transfer material 37 is not particularly limited, and a dry process such as vacuum deposition or sputtering can be used. However, as a method that can easily cope with an increase in size, at least a solution composed of a transfer material and a solvent is used as the partition pattern 34. It is preferable to use a coating method in which the coating is applied after drying inside and the solvent is dried. Specific examples of the coating method include ink jet, nozzle coating, electropolymerization and electrodeposition, offset and flexographic printing, lithographic printing, relief printing, gravure, screen printing and the like. In particular, it is important to accurately form a fixed amount of transfer material 37 in each partition pattern 34, and from this point of view, inkjet can be exemplified as a particularly preferable method.

  Without the partition pattern 34, the transfer materials 37 formed from the coating liquid are in contact with each other, and the boundary is not uniform, and a mixed layer is formed in no small amount. In order to prevent this, it is difficult to make the film thickness of the boundary region the same as the center when the gap is formed so as not to contact each other. In any case, since this boundary region cannot be transferred because it degrades the performance of the device, it is necessary to selectively transfer a region narrower than the pattern of the transfer material 37 on the donor substrate 30. Therefore, the width of the transfer material 37 that can actually be used is narrowed, and when an organic EL display is manufactured, the pixel has a small aperture ratio (the area of the non-light emitting region is large). In addition, since transfer is not possible because of the need to transfer except for the boundary region, if the type of transfer material of the transfer material 37 is different, they are sequentially lasered (for example, transfer materials 37R, 37G, and 37B). It is necessary to irradiate and transfer each independently, and high-precision alignment of high-intensity laser irradiation is required. Such a problem can be solved by performing batch transfer as described later using a donor substrate 30 having a transfer material 37 formed from a partition pattern 34 and a coating liquid.

  When applying a solution consisting of a transfer material and a solvent to the coating method, generally adding a surfactant, dispersant, etc., adjusts the viscosity, surface tension, dispersibility, etc. of the solution to make an ink. Often to do. However, in the donor substrate 30, if these additives exist as a residue in the transfer material, there is a concern that the donor substrate 30 may be taken into the transfer film 27 during transfer and adversely affect device performance. Accordingly, it is preferable to prepare the solution so that the purity of the transfer material after drying is 95% or more, and further 98% or more.

  As the solvent, known materials such as water, alcohol, hydrocarbon, aromatic compound, heterocyclic compound, ester, ether, ketone and the like can be used. In the ink jet method suitably used for the donor substrate 30, a solvent having a relatively high boiling point of 100 ° C. or higher, further 150 ° C. or higher is used, and the transfer material is excellent in solubility. Methylpyrrolidone (NMP), dimethylimidazolidinone (DMI), γ-butyllactone (γBL), cyclohexanone, ethyl benzoate and the like can be exemplified as suitable solvents.

  When the transfer material satisfies all the solubility, transfer resistance, and device performance after transfer, it is preferable to dissolve the original transfer material in a solvent. When the transfer material is poor in solubility, the solubility can be improved by introducing a soluble group with respect to a solvent such as an alkyl group into the transfer material. When a soluble group is introduced into a prototype of a transfer material that excels in device performance, the performance may deteriorate. In that case, for example, the soluble material can be eliminated by heat at the time of transfer to deposit the original material on the device substrate 10.

  In order to prevent the generation of gas and the entry of the desorbed material into the transfer film 27 when transferring the transfer material into which the soluble group has been introduced, the transfer material has a soluble group with respect to the solvent at the time of application, and heat or It is preferable to transfer the transfer material after the soluble group is converted or eliminated by light. For example, taking a material having a benzene ring as an example, as shown in Formula (1), a material having an acetyl group as a soluble group can be irradiated with light to be converted into a methyl group. In addition, as shown in Formula (2) and Formula (3), an intramolecular cross-linked structure such as an ethylene group or a diketo group is introduced as a soluble group, and then the original material is formed by a process of desorbing ethylene or carbon monoxide therefrom. It can also be restored. The conversion or elimination of the soluble group may be in a solution state before drying or in a solid state after drying. However, in consideration of process stability, it is preferably performed in a solid state after drying. Since the original molecule of the transfer material is often nonpolar, the molecular weight of the desorbed material is small so that the desorbed material does not remain in the transfer material when the soluble group is removed in the solid state. It is preferably polar (repulsive to the nonpolar prototype molecule). In order to remove oxygen and water adsorbed in the transfer material together with the desorbed material, it is preferable that the desorbed material easily reacts with these molecules. From these viewpoints, it is particularly preferable to convert or eliminate the solubilizing group in the process of eliminating carbon monoxide.

  Examples of the material having a benzene ring include condensed polycyclic compounds in addition to benzene itself. Examples of the condensed polycyclic compound include condensed polycyclic hydrocarbon compounds such as naphthalene, anthracene, naphthacene, pyrene, and perylene, as well as condensed polycyclic hetero compounds. Of course, these may be substituted or unsubstituted. The above conversion or elimination can be performed on one or more benzene rings of these compounds.

  When the light emitting layer 17 is formed as a transfer film of the device substrate 10 and has a single layer structure of a mixture of the host material and the dopant material, the transfer material for forming the light emitting layer 17 is composed of the host material and the dopant material. A mixture is preferred. When the coating method is used, when the transfer material 37 is arranged in the partition pattern 34, the transfer material 37 can be formed by applying and drying a mixed solution of the host material and the dopant material. You may apply | coat the solution of host material and dopant material separately. Even if the host material and the dopant material are not uniformly mixed at the stage where the transfer material 37 is formed, they may be mixed uniformly during the transfer. Further, the concentration of the dopant material in the light emitting layer 17 of the device substrate 10 can be changed in the film thickness direction by utilizing the difference in evaporation temperature between the host material and the dopant material at the time of transfer.

  Next, the partition pattern 34 of the donor substrate 30 will be described. The partition pattern 34 is not particularly limited as long as it is a material / configuration that defines the boundary of the transfer material 37 and is stable against the heat generated in the photothermal conversion layer 33. Examples of inorganic substances include oxides and nitrides such as silicon oxide and silicon nitride, glass and ceramics, and examples of organic substances include resins such as polyvinyl, polyimide, polybenzoxazole, polystyrene, acrylic, novolac, and silicone. . The well-known technique which manufactures the partition in a plasma television by the glass paste method can also be used. The thermal conductivity of the partition pattern 34 is not particularly limited. However, from the viewpoint of preventing heat from diffusing to the device substrate 10 facing through the partition pattern 34, it is preferable that the thermal conductivity is small like an organic substance. As materials excellent in patterning characteristics and heat resistance, polyimide and polybenzoxazole can be exemplified as preferable materials.

  The method for forming the partition pattern 34 is not particularly limited, and known techniques such as vacuum deposition, EB deposition, sputtering, ion plating, CVD, and laser ablation are used when an inorganic substance is used, and spin coating is used when an organic substance is used. Well-known techniques such as slit coating and dip coating can be used.

  The patterning method of the partition pattern 34 is not particularly limited, and a known photolithography method can be used. The partition pattern 34 may be patterned by an etching (or lift-off) method using a photoresist, or the partition pattern 34 is directly exposed and developed using a material in which photosensitivity is added to the resin material described above. It is also possible to perform patterning. Furthermore, a stamp method or an imprint method in which the material of the partition pattern 34 is formed on the entire surface and a mold is pressed thereto, an ink jet method or a nozzle jet method in which a resin material is directly formed by patterning, or various printing methods can be used. Thus, since the partition pattern 34 can be finely patterned with high accuracy by a photolithography method or the like, the space between the patterns of the partitioned transfer material 37 can be minimized. This leads to an effect that an organic EL display having a higher aperture ratio and excellent durability can be produced.

  The shape of the partition pattern 34 is not limited to the already illustrated lattice (matrix) structure. For example, when the transfer material 37 is composed of three types of transfer materials 37R, 37G, and 37B, the partition pattern The planar shape of 34 may be a stripe extending in the y direction. Further, as shown in FIG. 5, a partition pattern 34 having a width wider than that of the transfer material 37 can be formed. In this case, the process of preparing three donor substrates 30 on which three types of transfer materials 37R, 37G, and 37B are formed and transferring the donor substrate 30 so as to face each other is repeated three times. Thus, the transfer materials 37R, 37G, and 37B can be patterned on one device substrate 10. This is an example of an effective shape in high-precision fine patterning that requires a small pitch or gap between the transfer materials 37R, 37G, and 37B.

  The sectional shape of the partition pattern 34 is preferably a forward tapered shape in order to facilitate the evaporation transfer material to be uniformly deposited on the device substrate 10. As illustrated in FIG. 2, when a pattern such as the insulating layer 14 is present on the device substrate 10, the width of the insulating layer 14 (especially the upper width) is larger than the width of the partition pattern 34 (especially the upper width). ) Is preferably wider. Further, at the time of alignment, it is preferable to arrange so that the width of the upper portion of the insulating layer 14 is within the width of the upper portion of the partition pattern 34. In this case, even if the partition pattern 34 is thin, the donor substrate 30 and the device substrate 10 can be held in a desired gap by increasing the thickness of the insulating layer 14. The typical width of the partition pattern 34 is 5 to 50 μm and the pitch is 25 to 300 μm. However, the partition pattern 34 may be designed to an optimum value according to the application, and is not particularly limited.

  When the transfer material 37 is arranged in the partition pattern 34, when a coating method is used, the partition pattern 34 is prevented in order to prevent the solution from being mixed into another partition or climbing onto the upper surface of the partition pattern 34. Liquid repellent treatment (surface energy control) can be performed on the upper surface. As the liquid repellent treatment, a liquid repellent material such as a fluorine-based material can be mixed with the resin material forming the partition pattern 34, or a high concentration region of the liquid repellent material can be selectively formed on the surface or the upper surface. The partition pattern 34 may have a multilayer structure of materials having different surface energies, and the surface energy state is controlled by performing light irradiation or plasma treatment with a fluorine-containing material-containing gas after the partition pattern 34 is formed. Technology can be used.

  The partition pattern 34 is thicker than the average film thickness of the transfer material 37. This is an important point in the present embodiment. Then, the transfer material 37 does not directly contact the device substrate 10 even if there is some variation in the film thickness of the transfer material. The average film thickness of the transfer material is defined as the average thickness of the portion of the transfer material that exists inside the partition pattern (the portion that does not ride on the partition pattern). When the surface of the transfer material is relatively smooth, the film thickness can be measured using an optical interference method such as a confocal type. If the transfer material is not a continuous film, the surface shape can be measured by a stylus method such as an atomic force microscope, and the average film thickness can be determined from the level difference from the photothermal conversion layer. These measuring methods are not particularly limited.

  By facing the partition pattern 34 to the device substrate 10, it becomes easy to keep the gap between the photothermal conversion layer 33 or the transfer material 37 and the device substrate 10 at a constant value, and the evaporated transfer material is transferred to other partitions. The possibility of intrusion can be reduced. Further, if the partition pattern 34 is thick, the heat capacity increases and the heat conduction decreases. Therefore, the temperature of the part of the partition pattern 34 that protrudes from the transfer material 37 does not increase so much, and the base layer already formed on the device substrate 10 is prevented from being heated to a high temperature from the photothermal conversion layer 33 through the partition pattern 34. Is done. Since the temperature rise is reduced by the amount of heat capacity, it is hardly affected by degassing from the partition pattern 34. As a result, the device performance of the device substrate 10 does not deteriorate. For example, when the hole transport layer 16 is formed by vapor deposition on the entire surface, the hole transport layer 16 is also formed on the insulating layer 14 as shown in FIG. Will come in contact with. In the present invention, since the temperature rise of the partition pattern 34 is small, the hole transport material 16 is prevented from being heated and evaporated to be mixed with the hole transport material. When the hole transport layer 16 is formed by the ink jet method, the hole transport layer 16 is not formed on the insulating layer 14, and the partition pattern 34 is in contact with the insulating layer 14. Even in this case, the device substrate 10 is prevented from being heated via the insulating layer 14.

  The photothermal conversion layer 33 / transfer material 37 may instantaneously reach 500 ° C. On the other hand, it is preferable to suppress the temperature rise of the device substrate 10 to 100 ° C. or less. Although it is difficult to define numerical values in general, the same film thickness portion as the transfer material in the lower part of the partition pattern 34 is instantaneously heated to the same 500 ° C. as that of the transfer material. Assuming that the upper limit is 100 ° C., the thickness of the partition pattern 34 is preferably 500 ° C./100° C. = 5 times or more as compared with the average film thickness of the transfer material. Considering the influence of radiant heat and the like, it is more preferably 20 times or more. Even if the partition pattern 34 is high, there is no particular problem, but considering the presence of the transfer material 37 that is lost without reaching the device substrate 10 by adhering to the side surface of the partition pattern 34 during transfer, the thickness of the partition pattern 34 is increased. The thickness is preferably 10,000 times or less of the average film thickness of the transfer material.

In order to suppress the temperature rise of the device substrate 10, the thermal conductivity of the partition pattern 34 is preferably 1.0 W / mK or less, more preferably 0.3 W / mK or less, and the volume specific heat (= density × The specific heat is preferably 1.0 J / cm ³ K or more.
(3) Manufacturing Method of Organic EL Element Next, a manufacturing method of the organic EL element will be described focusing on a transfer process using the donor substrate 30.

  In the color display, at least the light emitting layer 17 needs to be patterned, and the light emitting layer 17 is a thin film that is suitably patterned using the transfer process of this embodiment. Further, only the light emitting layers 17R and 17G of the light emitting layer 17 are patterned by using the transfer process of the present embodiment, and the light emitting layer 17B and the layer serving as the R and G electron transport layers 18 are formed on the entire surface thereof. You can also. When it is necessary to pattern at least one layer such as the hole transport layer 16, the electron transport layer 18, and the second electrode 19, the pattern may be patterned using the transfer process of the present embodiment. In particular, since an electron transport material or a donor material is one of materials whose performance is likely to change due to the combination with the light emitting layer 17, the electron transport layer 18 is preferably patterned using the transfer process of the present embodiment. The insulating layer 14, the first electrode 15, the TFT, and the like are often patterned by a known photolithography method, but may be patterned using the transfer process of this embodiment.

When the transfer process of the present embodiment is applied, the underlying layer formed on the device substrate 10 differs depending on the thin film to be patterned. For example, when the light emitting layer 17 is patterned, the first electrode 15 and the hole transport layer 16 are formed as a base layer. Although a structure such as the insulating layer 14 is not essential, the edge pattern of the first electrode 15 is protected, and when the device substrate 10 and the donor substrate 30 are opposed to each other, the partition pattern 34 of the donor substrate 30 is From the viewpoint of preventing contact with and damage to the underlying layer already formed on the device substrate 10, it is preferably formed in advance on the device substrate 10. For the formation of the insulating layer 14, the materials, film formation methods, and patterning methods exemplified as the partition pattern 34 of the donor substrate 30 can be used. As for the shape, thickness, width, and pitch of the insulating layer 14, the shape and numerical values exemplified in the partition pattern 34 of the donor substrate 30 can be exemplified, and as shown in FIG. 2, the partition pattern 34 of the donor substrate 30, In a state where the position of the device substrate 10 with the insulating layer 14 is aligned, both the substrates 10 and 30 are arranged to face each other. At this time, the donor substrate 30 and the device substrate 10 can be opposed to each other in a vacuum, and the transfer space can be taken out into the atmosphere with the vacuum kept as it is. For example, the region surrounded by the partition pattern 34 of the donor substrate and / or the insulating layer of the device substrate 10 can be held in a vacuum. In this case, a vacuum sealing function may be provided at the periphery of the donor substrate 30 and / or the device substrate 10. When the base layer of the device substrate 10, for example, the hole transport layer 16 is formed by a vacuum process, the light emitting layer 17 is patterned by transfer, and the electron transport layer 18 is also formed by a vacuum process, the donor substrate 30, the device substrate 10, Are preferably opposed to each other in a vacuum, and transfer is performed in a vacuum. In this case, as a method of aligning the donor substrate 30 and the device substrate 10 with high accuracy in a vacuum and maintaining the facing state, for example, vacuum dropping of a liquid crystal material used in a manufacturing process of a liquid crystal display -Well-known techniques, such as a bonding process, can be used. In addition, the donor substrate 30 can be easily held by an electrostatic method by using the photothermal conversion layer 33 formed of a good conductor such as metal.

  The transfer atmosphere may be atmospheric pressure or reduced pressure. In addition, during the transfer of the first electrode 15 and the second electrode 19 or the like, reactive transfer such as reacting a transfer material with an active gas such as oxygen can be performed. However, in order to suppress the deterioration of the transfer material, it is preferably in an inert gas such as nitrogen gas or in a vacuum. If it is in an inert gas, it is possible to promote uniformity of film thickness unevenness during transfer by appropriately controlling the pressure. If it is under vacuum, it is possible to particularly promote the reduction of impurities mixed into the transfer film 27 and the lowering of the evaporation temperature. Further, the donor substrate 30 can be radiated or cooled during the transfer regardless of the transfer atmosphere.

  In the transfer, light typified by a laser is incident from the support 31 side of the donor substrate 30 and absorbed by the light-to-heat conversion layer 33, and the transfer material 37 is heated and evaporated by the heat generated there. To deposit.

  FIG. 6 is a cross-sectional view illustrating an example of a method of irradiating the donor substrate 30 with light. 6A, the donor substrate 30 includes a support 31, a photothermal conversion layer 33, a partition pattern 34, and a transfer material 37 of a transfer material existing in the partition pattern 34, and the device substrate 20 includes only the support 21. It is supposed to be. In this embodiment, as shown in FIG. 6B, light is incident from the support 31 side of the donor substrate 30, and at least a part of the transfer material 37 and at least a part of the partition pattern 34 are heated at the same time. It is preferable to irradiate the photothermal conversion layer 33 with light. By adopting such an arrangement, a temperature drop at the boundary between the partition pattern 34 and the transfer material 37 is suppressed, so that the transfer material existing at the boundary is sufficiently heated to transfer the uniform transfer film 27. Obtainable.

  FIG. 6B schematically shows a process in which the transfer material 37 is heated and evaporated and deposited as the transfer film 27 on the support 21 of the device substrate 20. At this time, the light irradiation can be stopped (the light irradiation of the portion is terminated by the movement of the light irradiation portion), and the light irradiation is continued as it is to transfer the entire right side portion of the transfer material 37. The left part can also be transferred. In this embodiment, if a material and light irradiation conditions are selected, an ablation mode in which the transfer material 37 reaches the support 21 of the device substrate 20 with the film shape maintained can be used. From the viewpoint of reduction, it is preferable to use a vapor deposition mode in which the transfer material 37 evaporates in a state of being loosened into 1 to 100 units of molecules (atoms) and transferred.

  In the vapor deposition mode, even if film thickness unevenness occurs in the transfer material 37 when formed by the coating method, the transfer material evaporates in a state of loosening to the molecular (atomic) level at the time of transfer and is deposited on the device substrate 20. The film thickness unevenness of the transfer film 27 is reduced. In addition, one of the problems of the conventional method in which the thin film formed by the coating method is directly used as the functional layer of the organic EL element is the film thickness unevenness. Therefore, for example, at the time of application, the transfer material is particles made of molecular aggregates such as pigment, and even if the transfer material 37 is not a continuous film on the donor substrate 30, it is loosened to the molecular level and evaporated at the time of transfer. By depositing, a transfer film 27 with excellent film thickness uniformity can be obtained on the device substrate 10.

  FIG. 6C irradiates the photothermal conversion layer 33 with light wider than the width of the transfer material 37 so that the entire width of the transfer material 37 and a part of the width of the partition pattern 34 are simultaneously heated. One of the preferable forms of this invention is shown. According to this arrangement, the desired pattern of the transfer film 27 can be efficiently obtained by one transfer. Alternatively, the load on the transfer material 37 can be further reduced by transferring half the film thickness of the transfer material 37 by the first light irradiation and transferring the other half by the second light irradiation. Further, one donor substrate 30 is used such that about half of the film thickness of the transfer material 37 is transferred to a certain device substrate 20 by one light irradiation, and the remaining half is transferred to another device substrate. Transfer to two device substrates can also be performed. If the film thickness of the transfer material 37 transferred to each device substrate is adjusted, transfer from one donor substrate to three or more device substrates is also possible.

  In this arrangement, as shown in FIG. 6D, the position of the light irradiation is displaced by δ, and the entire width of the transfer material 37 and a part of the width of the partition pattern 34 are heated at the same time. Similarly, a uniform transfer film 27 can be obtained. In the conventional light irradiation method shown in FIG. 7, the temperature is lowered at the boundary between the partition pattern 34 and the transfer material 37, and the uniformity of the transfer film 27 is extremely impaired when the light irradiation position is shifted. Considering the difficulty in aligning the light irradiation with high accuracy over the entire area of the substrate in the case of an increase in size, the method of the present embodiment significantly reduces the burden on the light irradiation device.

  FIG. 8 is a cross-sectional view showing an example of a method for irradiating a donor substrate with two or more different transfer materials 37 (in this example, three types of 37R, 37G, and 37B) corresponding to the partition pattern 34. And represents one of the preferred embodiments. Here, different transfer materials mean that the materials are different, the mixing ratio of a plurality of materials is different, or the film thickness and purity are different even if the materials are the same. According to this arrangement, only one donor substrate 30 is required for each transfer material, which is conventionally required, and the operation of facing the device substrate 10 can be completed only once. Three types of different transfer materials can be transferred by light irradiation for each type (only 37G in this example). At this time, for example, in order to reduce damage to the transfer material 37G, when light irradiation is performed by scanning light of relatively weak intensity at a low speed, the adjacent transfer material 37R or 37B is thermally diffused in the lateral direction. Some may evaporate. However, they are to be transferred later and, as a result, are the same as the concept of divided transfer shown in FIG. Furthermore, since the partition pattern 34 exists, there is no possibility that a mixture with the adjacent transfer material 37R or 37B is formed as the transfer film 27G.

  As often seen in display applications, when a set of transfer materials 37R, 37G, and 37B is repeatedly formed k times in the x direction and l times in the vertical y direction, for example, m (m Can be shortened to about 1 / m by scanning light in the y direction while simultaneously irradiating light onto a transfer material 37G having a positive number between 2 and k. Even in this case, if the light-to-heat conversion layer 33 is irradiated with light so as to heat a part of the transfer material 37G and the partition pattern 34, the influence of the light irradiation deviation represented by the displacement δ shown in FIG. The effect similar to that shown in FIG. 6D is obtained.

  FIG. 9 shows the width of each of two or more different transfer materials 37 (in this example, three types of 37R, 37G, and 37B) and the partition pattern 34 (in this example, the partition pattern sandwiched between 37R and 37G, 37G and 37B). By irradiating light-to-heat conversion layer 33 with light wider than the sum of the widths of two (34), two or more different transfer materials 37 (in this example, three types of 37R, 37G, and 37B) are collected at once. FIG. 3 is a view showing one of the preferred embodiments for transfer. Here, as shown in FIGS. 2 and 3, an example of transferring one set of 37R, 37G, and 37B at a time was shown. However, as is often seen in display applications, transfer materials 37R, 37G, When the set of 37B is repeatedly formed k times in the x direction and l times in the vertical y direction, for example, m sets (m is an integer of 2 to k) of transfer materials 37R, 37G, By scanning light in the y direction while simultaneously irradiating light to 37B, the transfer time can be shortened to about 1 / m. When m = k, as shown in FIG. 10A, the entire transfer material 37 is collectively transferred in one scan by irradiating light that covers the entire width of the transfer region 38 of the donor substrate 30. You can also With this arrangement, alignment of light irradiation with respect to the donor substrate 30 can be greatly reduced. As shown in FIG. 10B, when there are a plurality of transfer regions 38 on the substrate, it is also possible to transfer them all at once.

  This batch transfer can shorten the patterning time as compared with the conventional method in which each transfer material 37R, 37G, and 37B needs to be irradiated with light sequentially. Since the light is sufficiently absorbed by the photothermal conversion layer 33, each of the transfer materials 37R, 37G, and 37B having different light absorption spectra can be heated to the same temperature using the same light source. There is no concern that the device substrate 10 is heated. Since the partition pattern 34 is present, different transfer materials of the adjacent transfer material 37 can be mixed, or the transfer of the portion where the boundary position fluctuates can be eliminated. Absent.

  In the example of batch transfer described above, when the transfer materials 37R, 37G, and 37B have different evaporation temperatures (temperature dependence of vapor pressure), one light irradiation is performed in accordance with the transfer material having the highest evaporation temperature. Batch transfer may be performed. On the other hand, for example, when the transfer material 37R has the lowest evaporation temperature, the transfer material 37R is completely transferred by a single light irradiation, and a part of 37G and 37B is transferred. The remainder of 37B may be transferred, or may be divided into three or more transfers. Since the transfer time can be shortened to about 1 / m, the damage to the transfer material 37 can be further reduced by dividing the transfer into m times over the same time. The optimum one can be selected from a variety of transfer conditions in consideration of the time available for the transfer process and damage to the transfer material 37.

  The batch transfer has another effect. In the wide light irradiation range, the lateral thermal diffusion that has become a problem in laser transfer does not occur, so it is possible to irradiate light for a relatively long time, such as by scanning the laser at a relatively low speed. It becomes possible. Therefore, it becomes easier to control the maximum temperature of the transfer material 37 and fine patterning can be performed with high accuracy. In addition, it is possible to minimize a decrease in device performance without damaging the transfer material 37 during transfer. When the damage to the transfer material 37 is reduced, the damage to the partition pattern 34 is also reduced at the same time, and even if the partition pattern 34 is formed of an organic material, the deterioration hardly occurs. Therefore, the cost required for patterning can be reduced because the donor substrate can be reused a plurality of times. In addition, since it is not necessary to control the light irradiation position as strictly as in the conventional method, the mechanism of the light irradiation apparatus can be simplified.

  FIG. 11 shows another example of batch transfer according to this embodiment. The transfer materials 37R and 37G are irradiated by irradiating light having a width corresponding to the sum of the width of the transfer material 37G and the width of the partition pattern 34 so as to straddle the transfer materials 37R and 37G, as shown in FIG. A part of each is transferred at once. By repeating this transfer method many times while shifting the position of the next irradiation light by the width of the irradiation light, the transfer of all the transfer materials 37R, 37G, and 37B is finally completed. In this method, it is not necessary to strictly control the positional relationship between the irradiation light and the donor substrate. Furthermore, it is not necessary to shift the position of the next irradiation light exactly by the width of the previous irradiation light, and they may be overlapped. The light may finally irradiate the entire transfer region, and the width of irradiation light, the order of irradiation, the degree of overlap, and the like are not particularly limited. Further, even when the RGB sub-pixels called a delta arrangement on the display are not arranged in a straight line, the irradiation light can be scanned linearly, so that the transfer can be easily performed.

  In the above example, rectangular light is scanned in the y direction. However, as shown in FIG. 12, scanning can be performed in the x direction of the arrangement of the transfer materials 37R, 37G, and 37B. Further, the scanning speed and light intensity need not be constant. In scanning in the x direction, for example, the scanning speed and light intensity are set so that the conditions are optimal for the evaporation temperatures of the transfer materials 37R, 37G, and 37B. It can also be modulated during the scan. The scanning direction is preferably a direction along the partition pattern 34 in the x direction or the y direction, but is not particularly limited, and scanning in an oblique direction is also possible.

  The scanning speed is not particularly limited, but a range of 0.01 to 2 m / s is generally used. In this embodiment, one of the purposes is to reduce damage to the transfer material 37 by scanning at a lower speed under the condition that the energy density of light irradiation is relatively small. The speed is preferably 0.6 m / s or less, more preferably 0.3 m / s or less.

  As a light source of irradiation light, a laser that can easily obtain high intensity and excellent in shape control of irradiation light can be exemplified as a preferable light source. However, a light source such as an infrared lamp, a tungsten lamp, a halogen lamp, a xenon lamp, or a flash lamp is used. You can also As the laser, a known laser such as a semiconductor laser, a fiber laser, a YAG laser, an argon laser, a nitrogen laser, or an excimer laser can be used. Since the continuous wave mode (CW) laser can reduce damage to the transfer material 37, it is preferable to the intermittent oscillation mode (pulse) laser in which high intensity light is irradiated in a short time.

  The wavelength of the irradiation light is not particularly limited as long as the irradiation atmosphere and the donor substrate support 31 have small absorption and are efficiently absorbed by the photothermal conversion layer 33. Therefore, not only visible light region but also ultraviolet light to infrared light can be used. Considering a suitable material of the support 31 of the donor substrate, 300 nm to 5 μm can be exemplified as a preferable wavelength region, and 380 nm to 2 μm can be illustrated as a more preferable wavelength region.

  The shape of irradiation light is not limited to the rectangle illustrated above. The optimum shape can be selected according to the transfer conditions such as linear, elliptical, square, polygonal. Irradiation light may be formed by superposition from a plurality of light sources, or conversely, a single light source may be divided into a plurality of irradiation lights. As shown in FIG. 13, each irradiation time (heating time) to the transfer materials 37R, 37G, and 37B is adjusted by scanning light having a stepwise width in the scan direction, and each of the transfer materials 37R, 37G, and 37B is adjusted. Batch transfer optimized for the evaporation temperature can be performed. It is also possible to make the irradiation energy (intensity × irradiation time) constant by modulating the width in the scanning direction of the light corresponding to unevenness of the intensity of the irradiation light. Moreover, as shown in FIG. 14, you may scan in ay direction by the arrangement | positioning which irradiates rectangular light diagonally. When the shape (width) of the irradiation light is fixed, it is possible to cope with transfer having various pitches without requiring a large change in the optical system.

  Further, as shown in FIG. 15A, light covering the entire region of the transfer region 38 of the donor substrate 30 can be irradiated. In this case, all transfer materials can be collectively transferred without scanning the irradiation light. Further, as shown in FIG. 15B, step irradiation may be used in which light that partially covers the transfer region 38 of the donor substrate 30 is irradiated and then an unirradiated portion is irradiated. Also in this case, since the positions before and after the irradiation light may be overlapped, the alignment of the light irradiation can be greatly reduced.

It is difficult to exemplify the preferable range of the intensity of irradiation light and the heating temperature of the transfer material. These include uniformity of irradiation light, irradiation time (scanning speed), material and thickness of the donor substrate support 31 and photothermal conversion layer 33, reflectance, material and shape of the partition pattern 34, material of the transfer material 37, This is because it depends on various conditions such as thickness. A typical value of the energy density absorbed by the photothermal conversion layer 33 is a range of 0.01 to 10 J / cm ² , and a heating temperature of the transfer material 37 is a range of 220 to 400 ° C.

  FIG. 16 is a conceptual diagram showing a temperature change of the transfer material 37 (or the photothermal conversion layer 33) when light is irradiated for a certain time. Since it depends on various conditions, it cannot be generally stated, but as shown in FIG. 16 (a), the temperature gradually increases when the irradiation intensity (power density) is constant, and increases even after reaching the target (evaporation temperature). Tend to. Even under these conditions, transfer can be performed without any problem depending on the thickness, heat resistance, and irradiation time of the transfer material 37. On the other hand, as a preferable irradiation method for further reducing damage to the transfer material 37, as shown in FIG. 16B, the intensity is distributed so that the temperature is constant near the target and the period is long. There is an example in which the irradiation intensity at a certain point is temporally changed using the irradiated light. The ability to reduce damage to the transfer material 37 means that damage to the partition pattern 34 can be reduced at the same time. For example, even when the partition pattern 34 is formed using a photosensitive organic material, the partition pattern 34 deteriorates. Without increasing the number of times the donor substrate is reused.

  FIG. 17 is a perspective view showing a method of forming irradiation light. As shown in FIG. 17A, rectangular irradiation light can be cut out from a circular light beam by the optical mask 41. In addition to the optical mask 41, a knife edge or an optical interference pattern may be used. As shown in FIGS. 17B and 17C, the irradiation light can be formed by condensing or expanding the light from the light source 44 by the lens 42 and the mirror 43. In addition, by appropriately combining the optical mask 41, the lens 42, the mirror 43, etc., the irradiation light can be formed into an arbitrary shape. For example, the long axis direction of the rectangular irradiation light has a uniform irradiation intensity. However, it can also be designed to have a Gaussian distribution in the minor axis direction.

  FIG. 17D shows an example for realizing the time dependency of the irradiation intensity shown in FIG. The irradiation light is condensed obliquely through the lens 42 with respect to the surface of the donor substrate 30. If the near side of the virtual focal plane 45 indicated by the broken line is arranged so as to substantially coincide with the photothermal conversion layer 33 (not shown) of the donor substrate 30, the near side becomes an on-focus condition that coincides with the focal length of the lens 42. Since the irradiation density is maximized and the back side is in an off-focus condition that deviates from the focal length, the irradiation density is reduced by blurring of light. When the irradiation light is scanned from the back to the front in such an arrangement, the time dependency of the irradiation intensity conceptually shown in FIG. 16B can be obtained.

  In this way, by irradiating the partition pattern 34 with light simultaneously with the transfer material 37 on the donor substrate 30, high-precision fine patterning is possible even for a large size. The formation of the partition pattern 34 that is a foreign substance other than the transfer material on the donor substrate 30 may cause the partition pattern 34 itself to be peeled off and transferred, or impurities from the partition pattern 34 to be mixed into the transfer material. The transfer material is heated to a relatively high temperature as in the vapor deposition transfer method in which the photothermal conversion layer 33 is installed on the donor substrate 30 to absorb light and the transfer material is transferred by the generated heat. In this method, irradiating light so as to positively heat the partition pattern 34, which is a foreign object, has no precedent because it has a high possibility of deteriorating device performance. However, in this embodiment, fine patterning with high accuracy can be performed for the first time by irradiating light on the donor substrate on which the photothermal conversion layer 33 is installed so as to heat the partition pattern 34 simultaneously with the transfer material 37. It is a thing. That is, according to such an irradiation method, the temperature drop at the boundary between the partition pattern 34 and the transfer material 37 as shown in FIG. 7 is suppressed, so that the transfer material existing at the boundary is also sufficiently heated and transferred. be able to. Therefore, since the film thickness distribution of the transfer thin film is made more uniform than before, adverse effects on device performance can be prevented. Further, since the intensity of light used can be reduced, even when the transfer material 37 and the partition pattern 34 are heated so that they are heated at the same time, the transfer material 37 and the partition pattern 34 deteriorate, and the partition pattern. The adverse effect on the device performance caused by the peeling of 34 and the degassing of the partition pattern 34 can be minimized.

  In addition, since the partition pattern 34 is thicker than the average film thickness of the transfer material 37, the underlying layer already formed on the device substrate is prevented from being heated to a high temperature through the partition pattern. Can prevent adverse effects.

  The transfer donor substrate and the organic EL element manufacturing method using the same according to the embodiment of the present invention have been described above. Next, examples related to the embodiment of the present invention will be described. The present invention is not limited to the above-described embodiment and the following examples, and various design changes can be made within the scope of the matters described in the claims, and the donor substrate 30 can be changed. Of course, the use of is not limited to the manufacture of organic EL elements.

Example 1
A donor substrate was prepared as follows. A non-alkali glass substrate was used as the support 31, and after cleaning / UV ozone treatment, a titanium film having a thickness of 1.0 μm was formed on the entire surface by sputtering as the photothermal conversion layer 33. Next, the photothermal conversion layer 33 is subjected to UV ozone treatment, and then a positive polyimide photosensitive coating agent (DL-1000, manufactured by Toray Industries, Inc.) is spin-coated thereon, prebaked and UV exposed, and then developed. The exposed portion was dissolved and removed with a liquid (ELM-D, manufactured by Toray Industries, Inc.). The polyimide precursor film thus patterned was baked on a hot plate at 350 ° C. for 10 minutes to form a polyimide-based partition pattern 34. The partition pattern 34 had a height of 2 μm and a cross section of a forward tapered shape. The thermal conductivity was about 0.2 W / mK, and the volume specific heat was about 1.2 J / cm ³ K. Openings that expose the photothermal conversion layer 33 with a width of 80 μm and a length of 280 μm were arranged in the partition pattern 34 at a pitch of 100 and 300 μm, respectively. On this substrate, a chloroform solution containing ₃ wt% of Alq ₃ was spin-coated to form a transfer material 37 having an average thickness of 25 nm made of Alq ₃ in the partition pattern 34 (opening).

The device substrate 10 was produced as follows. A non-alkali glass substrate (manufactured by Geomat Co., Ltd., sputtering film-formed product) on which an ITO transparent conductive film was deposited to 140 nm was cut into 38 × 46 mm, and ITO was etched into a desired shape by a photolithography method. Next, the polyimide precursor film patterned similarly to the donor substrate was baked at 300 ° C. for 10 minutes to form a polyimide-based insulating layer. The height of this insulating layer was 1.8 μm and the cross section was a forward tapered shape. Openings exposing ITO with a width of 70 μm and a length of 270 μm were arranged at a pitch of 100 and 300 μm inside the pattern of the insulating layer. This substrate was subjected to UV ozone treatment, installed in a vacuum deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 3 × 10 ⁻⁴ Pa or less. By the resistance heating method, as the hole transport layer 16, copper phthalocyanine (CuPc) was deposited to 20 nm, NPD was deposited to 40 nm, and the entire light emitting region was deposited by vapor deposition.

Next, the positions of the partition pattern 34 of the donor substrate and the insulating layer of the device substrate 10 were made to face each other, held in a vacuum of 3 × 10 ⁻⁴ Pa or less, and then taken out into the atmosphere. The transfer space partitioned by the insulating layer and the partition pattern 34 was kept in a vacuum. In this state, a laser (light source: semiconductor laser diode) having a wavelength of about 800 nm is irradiated from the glass substrate side of the donor substrate so that a part of the transfer material 37 and a part of the partition pattern 34 are heated at the same time. 37 Alq ₃ was transferred as the light emitting layer 17 onto the hole transport layer 16 which was the underlayer of the device substrate 10. The laser intensity was about 300 W / mm ² , the scanning speed was 1.25 m / s, and repeated scanning was performed by overlapping the lasers so as to be transferred over the entire light emitting region.

The device substrate 10 after the transfer of Alq ₃ was placed in the vacuum deposition apparatus again and evacuated until the degree of vacuum in the apparatus became 3 × 10 ⁻⁴ Pa or less. E-1 shown below as an electron transport layer 18 was deposited on the entire surface of the light emitting region by resistance heating. Next, lithium fluoride was deposited to 0.5 nm as a donor material (electron injection layer), and aluminum was deposited to 100 nm as the second electrode 19 to produce an organic EL device having a 5 mm square light emitting region.

After sealing the organic EL element, when a constant current of ^2.5 mA / cm ² was passed, good light emission was obtained. Immediately after starting to flow, the initial luminance and the initial voltage were set, and a constant current was continued to flow, and the time until the luminance decreased to half from the initial luminance was measured as the luminance half-time. Obtained as a reference value in relative evaluation with the results of the comparative example.

Example 2
An organic EL element was produced in the same manner as in Example 1 except that the partition pattern 34 was formed by the following procedure. Glass powder (composition: Li ₂ O: 9%, SiO ₂ : 20%, B ₂ O ₃ : 31%, BaO: 4%, Al ₂ O ₃ : 24%, ZnO: 2%, MgO: 6%, CaO : 4%) Weighed at a ratio of 0.08 parts by weight of organic dye (Sudan) to 70 parts by weight. Sudan was dissolved in acetone, a dispersant was added, and the mixture was stirred uniformly with a homogenizer. Glass powder was added to this solution and uniformly dispersed, and then dried at a temperature of 100 ° C. to evaporate acetone. Thus, a powder in which the surface of the glass powder was uniformly coated with an organic dye film was produced. Polymer (weight average molecular weight 43,000 obtained by addition reaction of 0.4 equivalent of glycidyl methacrylate to the carboxyl group of a copolymer consisting of 40% methacrylic acid, 30% methyl methacrylate and 30% styrene, acid 40% γ-butyrolactone solution of photopolymer with a valence of 95), monomer, photopolymerization initiator, sensitizer 0.08% sudan, polymer 37.5%, monomer 12.75%, initiator 4.8% The sensitizer was mixed at a ratio of 4.8% and dissolved homogeneously. A filtered glass solution and 70% of the above glass powder were added and mixed and dispersed with three rollers to prepare a photosensitive glass paste. This paste was screen-printed on the photothermal conversion layer 33, held at 80 ° C. for 1 hour and dried, exposed to a high-pressure mercury lamp, developed with a monoethanolamine aqueous solution, and washed with water. Thereby, the partition pattern 34 which consists of glass was obtained by baking the donor substrate from which the part which has not been photocured was removed in air at 560 degreeC for 15 minutes. The partition pattern 34 had a thickness of 2 μm, a thermal conductivity of about 0.9 W / mK, and a volume specific heat of about 1.6 J / cm ³ K. The initial luminance, initial voltage, and luminance half time of the organic EL element were almost the same as the reference values of Example 1.

Comparative Example 1
An organic EL element was produced in the same manner as in Example 1 except that the transfer material was formed on the entire surface without the partition pattern 34. Since there is no partition pattern, the donor substrate 30 has a structure in which a support 31 made of glass, a photothermal conversion layer 33, and a transfer material 37 are simply laminated. Therefore, the transfer material 37 of the donor substrate and the insulating layer of the device substrate 10 face each other in direct contact with each other, and the transfer space was kept in a vacuum. There was no need to align the donor substrate 30 and the device substrate 10. However, since the hole transport layer 16 adhering to the upper part of the insulating layer 14 of the device substrate 10 is in contact with the transfer material 37, the hole transport layer 16 is substantially the same as the transfer material when the light emitting layer is transferred. When heated to the temperature, it evaporates to form a mixed film of the light emitting material and the hole transport layer, the initial luminance is reduced to 60% or less of the reference value of Example 1, and the initial voltage is 1 Increased by more than 5V.

Comparative Example 2
Organic EL in the same manner as in Example 1 except that after the partition pattern 34 made of polyimide was formed, the partition pattern was thinned to a thickness of 20 nm thinner than the average film thickness of the transfer material using UV-ozone treatment. An element was produced. The initial luminance and the initial voltage were almost the same as in Comparative Example 1.

Example 3
The organic material is the same as in Example 1 except that carbon fine particles are mixed with polyimide to form a partition pattern 34 having a thickness of 100 nm, a thermal conductivity of about 1.8 W / mK, and a volume specific heat of about 1.7 J / cm ³ K. An EL element was produced. Since the partition pattern 34 has a relatively high thermal conductivity, the partition pattern 34 is likely to rise in temperature during transfer, and the hole transport layer 16 attached to the upper portion of the insulating layer 14 of the device substrate 10 during transfer of the light emitting layer is about 200. It was estimated that the temperature rose to ℃, and a slight evaporation of the hole transport material was observed. Compared with Example 1, the initial luminance was the same or slightly decreased, and the initial voltage increased by about 0.3V.

The expanded sectional view which shows the example of the typical structure of the device substrate in which the organic EL element was formed. The expanded sectional view which shows the example of the method of forming a transfer film in a device substrate using the donor substrate by embodiment of this invention. The enlarged plan view in FIG. Sectional drawing explaining an example of the transfer auxiliary layer in embodiment of this invention. The another example of the division pattern in embodiment of this invention is shown. Sectional drawing which shows an example of the patterning method by embodiment of this invention. Sectional drawing explaining the problem in the conventional light irradiation arrangement | positioning. Sectional drawing which shows another example of the patterning method by embodiment of this invention. Sectional drawing which shows an example of the patterning method of batch transfer by embodiment of this invention. The perspective view which shows another example of the light irradiation method in embodiment of this invention. Sectional drawing which shows another example of the patterning method of batch transfer by embodiment of this invention. The top view which shows another example of the light irradiation method in embodiment of this invention. The top view which shows another example of the light irradiation method in embodiment of this invention. The top view which shows another example of the light irradiation method in embodiment of this invention. The perspective view which shows another example of the light irradiation method in embodiment of this invention. The conceptual diagram explaining the time change of the light intensity distribution and transfer material temperature in embodiment of this invention. The perspective view which shows an example of the shaping | molding method of the irradiation light in embodiment of this invention.

Explanation of symbols

10 Organic EL elements (device substrates)
11 Support 12 TFT (including extraction electrode)
DESCRIPTION OF SYMBOLS 13 Flattening layer 14 Insulating layer 15 1st electrode 16 Hole transport layer 17 Light emitting layer 18 Electron transport layer 19 Second electrode 20 Device substrate 21 Support body 27 Transfer film 30 Donor substrate 31 Support body 33 Photothermal conversion layer 34 Partition pattern 37 Transfer material 38 Transfer region 39 Transfer auxiliary layer 41 Optical mask 42 Lens 43 Mirror 44 Light source 45 Virtual focal plane

Claims (6)

A support, a photothermal conversion layer formed on the support, a partition pattern formed on the photothermal conversion layer, and a transfer material formed in the partition pattern, wherein the thickness of the partition pattern is A donor substrate for transfer, characterized in that it is thicker than the average film thickness of the transfer material. The transfer donor substrate according to claim 1, wherein there are two or more types of the transfer material. 3. The transfer donor substrate according to claim 1, wherein the partition pattern is thicker than 5 times the average film thickness of the transfer material. 4. The donor substrate for transfer according to claim 1, wherein the partition pattern has a thermal conductivity of 1.0 W / mK or less. 5. The donor donor substrate for transfer according to claim 1, wherein the partition pattern has a volume specific heat of 1.0 J / cm ³ K or more. A method for manufacturing a device, comprising: a step of causing the transfer donor substrate according to claim 1 to face a device substrate; and a step of irradiating light to the photothermal conversion layer.

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