JP4040916B2 - Device manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing various elements having a thin film on a substrate surface.
[0002]
[Prior art]
Conventionally, organic devices using organic substances include organic transistors, organic solar cells, organic EL elements, etc. Among them, organic EL elements are manufactured by depositing organic substances on a substrate by a dry process or a wet process. ing. Examples of the organic film formation method in the wet process include a spin coating method, an ink jet method, a printing method, a dispenser method, and the like, and has an advantage that the organic material can be easily formed on the substrate.
[0003]
In the production of an organic EL element, a method for patterning an electrode layer or an organic EL layer includes a method for depositing an electrode layer material or an organic EL layer material through a pattern mask, a method for separately applying an ink jet method, or the like.
[0004]
[Problems to be solved by the invention]
However, in the above method, the simplicity of the manufacturing process, the low utilization efficiency of materials, and the influence of environmental conditions during manufacturing remain as problems. That is, in the above evaporation method, the finer the pattern of the pattern mask, the thinner the pattern mask is required, and the fine processing of the pattern mask becomes difficult. Furthermore, if the gap between the substrate and the pattern mask is wide, accurate vapor deposition film formation is difficult due to the wraparound of the vapor, and if the substrate and the pattern mask are brought into close contact with each other, there are problems such as damaging the substrate itself. An accurate vacuum device is essential, and there is a problem in terms of cost.
[0005]
Furthermore, in the latter ink jet method, a flight curve of a droplet due to a slight angle deviation occurs, and processing on the substrate is required for the correction. In addition, there is a problem that advanced techniques are required to form the same amount of droplets.
Accordingly, an object of the present invention is to provide a method of manufacturing an element that does not adversely affect the substrate and has high patterning accuracy.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, in a method for manufacturing a device for forming a thin film on a substrate, a solution of a material constituting the thin film is frozen, and the frozen material is disposed in a desired region on the substrate. Then, a method for manufacturing an element is provided, in which the film is thawed to form a film.
According to the method described above, the material solution is frozen and placed at a predetermined position on the substrate, so that the position of the thin film can be limited, and the thin film can be easily patterned on the substrate.
[0007]
The frozen material is preferably spherical in terms of handling. For example, spheroidization can be easily performed by forming droplets from the solution, rapidly cooling the droplets and freezing them into a sphere. it can. Moreover, the spheroidized frozen material can be sieved to obtain a particle size distribution that is easy to use.
[0008]
On the other hand, the substrate on which the frozen material is arranged can be formed with a concave portion on the surface of the substrate so that the frozen material is held at a predetermined position on the substrate, and the frozen material can be arranged in the concave portion. Further, as a method for arranging the frozen substance on the substrate, a method of arranging the frozen substance on the substrate through a pattern mask can be mentioned. The above-described method of the present invention is particularly useful for producing an organic EL device.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in more detail with reference to preferred embodiments. The element manufacturing method of the present invention is characterized in that the solution of the constituent material of the element is frozen, and the frozen material is disposed at a predetermined position on the element substrate. This has a great feature in that the frozen material can be arranged at a predetermined position on the substrate.
[0010]
Hereinafter, the present invention will be described more specifically with reference to the method for producing an organic EL element as an example.
(Organic EL element constituent material solution)
The solution of the organic EL element constituent material used in the present invention will be described. In the present invention, it is necessary to select a solvent that can be performed at a temperature that does not affect the organic EL material in the drying step in which the solution of the organic EL element constituent material is solidified at a predetermined temperature and the solvent is removed. For example, xylene is preferably used.
[0011]
(Freezing / sorting method)
The material solution freezing method used in the present invention will be described. Any freezing method may be used for freezing a solution of a constituent material of an organic EL element (for example, an organic light emitting material) as long as a frozen product can be obtained. In order to make the shape of the frozen material spherical, a method capable of rapid cooling is preferable. For example, a spherical frozen product can be obtained by a method such as dropping a droplet of the above solution into liquid nitrogen. In the present invention, any rapid cooling freezing method may be used as long as the above-mentioned frozen material can be obtained. By making the frozen material spherical, the volume of the frozen material can be made uniform. This is because it is possible to separate frozen products of the same volume with a sieve or the like. Further, by separating the frozen material, the film thickness can be easily controlled during film formation.
[0012]
(Frozen object fixation)
In the present invention, the material solution is frozen, placed at a predetermined position on the substrate, and subjected to a melting and drying process, whereby the film formation position of the molten material can be limited and patterning can be easily performed. It becomes possible. In addition, in order to place the frozen material at a predetermined position on the substrate, a concave portion such as a cell or a groove is formed on the substrate, or a pattern mask is placed on the substrate, and the frozen material is placed and fixed in a pattern on the substrate. May be. You may adjust the space | interval of a board | substrate and a mask as needed. As the pattern mask, any mask may be used as long as the frozen material can be arranged at a predetermined position.
[0013]
Moreover, as a method of arranging the frozen material on the substrate, there is a method in which an adhesive layer is formed in an arbitrary pattern on the substrate, and the frozen material is adhered and fixed to the adhesive layer. In this case, after the adhesive layer is once formed, the frozen layer is heated and adhered to the adhesive layer in a state where the adhesive layer is heated, and then the frozen material is melted to form a film. For example, in the case of an organic EL element, when the three-color light emitting EL element is formed using the frozen material having three different melting points, three kinds of adhesives having different melting points (or different softening points) are used as the adhesive. Each frozen material can be used to form a separate film depending on the melting point or the softening point of each adhesive.
[0014]
For example, as an example of patterning for three-color light emission of an EL layer, adhesives A, B, and C having three different melting points or softening points are previously applied on a substrate by patterning and drying, Three types of frozen materials A, B and C are prepared, and the adhesive A that becomes adhesive at the lowest temperature is made adhesive by heating or the like, and only the frozen material A is attached to the adhesive layer A. At this time, since the other adhesive layers B and C are not adhesive, the frozen material A does not adhere to the regions of the adhesive layers B and C. Subsequently, the adhesive layer C does not become adhesive, but the frozen material B is adhered to the adhesive layer B at a temperature at which the adhesive layer B becomes adhesive, and then the adhesive layer C having the highest melting point or softening point is made adhesive. Freeze C is adhered. Even in this way, different frozen materials can be fixed in a pattern on the substrate. Needless to say, the adhesive solution may be used as a frozen material in the same manner as the EL material solution.
[0015]
Moreover, it is preferable that the frozen material is arranged on the substrate in an environment where the frozen material is not dissolved. This facilitates handling of the frozen material. Further, it is preferable that the working atmosphere is filled with an inert gas, nitrogen, or the like so that the frozen substance does not adhere to a liquid state such as moisture, and the operation is performed in an environment where the liquid state such as moisture is removed.
[0016]
(Fixing of molten solution)
In addition, a liquid repellent process or a wettability changing layer may be formed on the substrate surface so that the solution generated by melting the frozen material does not flow out to a predetermined region of the substrate.
(Droplet formation method)
Examples of a method for forming droplets from a solution of a material constituting the EL element include a syringe, a syringe, a pipette, a micropipette, a micropump, an ink jet, and a dispenser. It is preferable to use the liquid droplets by changing the size of the droplets according to the film formation region on the substrate.
[0017]
(EL layer)
In the method of the present invention, the EL layer provided in the EL element is not particularly limited as long as it causes electroluminescence. The EL layer is further composed of a light emitting layer as an essential layer, an optional layer, a hole transport layer for transporting holes to the light emitting layer, and an electron transport layer for transporting electrons (these are collectively referred to as a charge transport layer). And a hole injection layer that injects holes into the light emitting layer or the hole transport layer and an electron injection layer that injects electrons into the light emitting layer or the electron transport layer (these are collectively referred to as a charge injection layer). May be provided). Examples of the material constituting these EL layers include the following.
[0018]
(Light emitting layer)
<Dye system>: cyclopentadiene derivative, tetraphenylbutadiene derivative, triphenylamine derivative, oxadiazole derivative, pyrazoloquinoline derivative, distyrylbenzene derivative, distyrylarylene derivative, pyrrole derivative, thiophene ring compound, pyridine ring compound, Examples include perinone derivatives, perylene derivatives, oligothiophene derivatives, trifumanylamine derivatives, oxadiazole dimers, virazoline dimers, and the like.
[0019]
<Metal complex system>: Aluminum quinolinol complex, benzoquinolinol beryllium complex, benzoxazole zinc complex, benzothiazole zinc complex, azomethylzinc complex, porphyrin zinc complex, europium complex, etc. And a metal complex having a rare earth metal such as Dy and having a ligand such as oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, and quinoline structure.
[0020]
<Polymer system>: Polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyvinylcarbazole, polyfluorene derivatives, and the like.
[0021]
<Doping material>: Perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazoline derivatives, decacyclene, phenoxazone, and the like.
[0022]
(Hole injection layer (anode buffer material))
Examples include phenylamine-based, starburst-type amine-based, phthalocyanine-based, vanadium oxide, molybdenum oxide, ruthenium oxide, oxides such as aluminum oxide, amorphous carbon, polyaniline, and polythiophene derivatives.
[0023]
(Electron injection layer (cathode buffer material))
Examples thereof include aluminum lithium, lithium fluoride, strontium, magnesium oxide, magnesium fluoride, strontium fluoride, calcium fluoride, barium fluoride, aluminum oxide, strontium oxide, calcium, polymethyl methacrylate, and sodium polystyrene sulfonate.
The EL layer material used in the present invention is not particularly limited as long as it is soluble or dispersed in a solvent. Alternatively, it may be dispersed in a resin and dissolved in a solvent.
[0024]
(Insulating layer)
The insulating layer provided in one embodiment of the EL element is provided in order to stop the supply of electric charge from the electrode to the EL layer and prevent the portion where the insulating layer is provided from emitting light. Examples of such materials include photosensitive polyimide resins, acrylic resins, other photocurable resins, thermosetting resins, and inorganic materials. The material for the insulating layer is not particularly limited as long as it is soluble or dispersed in a solvent. Alternatively, it may be dispersed in a resin and dissolved in a solvent.
[0025]
(Partition wall material in EL layer)
A partition wall may be provided in the EL layer, and this partition wall is particularly useful when combining EL layers emitting different colors. Examples of such a material include a photosensitive polyimide resin, an acrylic resin, a photocurable resin, a thermosetting resin, and a water repellent resin. The material for the partition wall is not particularly limited as long as it is soluble or dispersed in a solvent. Alternatively, it may be dispersed in a resin and dissolved in a solvent.
[0026]
(First electrode and second electrode)
In the structure of the EL element, the electrode provided on the substrate first is called a first electrode, and the electrode provided on the EL layer is called a second electrode. These electrodes are not particularly limited, but preferably the electrodes are composed of an anode and a cathode. In this case, the first electrode may be either an anode or a cathode. Either the anode or the cathode is transparent or translucent, and the anode is preferably a conductive material having a large work function so that holes can be easily injected, and conversely, the cathode can easily inject electrons. In particular, a conductive material having a small work function is preferable. A plurality of materials may be mixed and used. Each of the electrodes preferably has a resistance as small as possible. Generally, a metal material is used, but an organic substance or an inorganic substance may be used.
[0027]
Specifically, preferred anode materials include ITO, indium oxide, gold, polyaniline, and cathode materials include magnesium alloys (MgAg and others), aluminum alloys (AlLi, AlCa, AlMg and others), metallic calcium, and the like. The shape of the electrode is not particularly limited and is typically formed on the entire surface of the EL layer, but may be formed in some pattern. Further, the material of the electrode used for the EL element is not particularly limited as long as it is soluble or dispersed in a solvent. Alternatively, it may be dispersed in a resin and dissolved in a solvent.
[0028]
(substrate)
In the EL element, the substrate is provided with an electrode and an EL layer thereon, and can be made of a transparent material if desired, but may be an opaque material. In the EL element, the substrate may be the first electrode itself, but the first electrode is usually provided directly or via an intermediate layer on the surface of the substrate that maintains strength. As such a substrate, an inorganic material such as glass or a resin can be used.
[0029]
The resin is not particularly limited as long as it can be formed into a film, but a polymer material having relatively high solvent resistance and heat resistance is preferable. Moreover, you may use the base material which has gas barrier property which interrupts | blocks gas, such as a water | moisture content and oxygen, as needed. Specifically, fluorine resin, polyethylene, polypropylene, polyvinyl chloride, polyvinyl fluoride, polystyrene, ABS resin, polyamide, polyacetal, polyester, polycarbonate, modified polyphenylene ether, polysulfone, polyarylate, polyetherimide, polyether mon Phon, Polyamideimide, Polyimide, Polyphenylene sulfide, Liquid crystalline polyester, Polyethylene terephthalate, Polybutylene terephthalate, Polyethylene naphthalate, Polycyclohexylene dimethylene terephthalate, Polyoxymethylene, Polyethersulfone, Polyetheretherketone, Polyacrylate, Acrylonitrile Styrene resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, Epoxy resins, polyurethane resins, silicone resins, and amorphous polyolefins and the like, may be used as long as satisfying the polymeric material also in this other, may be a copolymer of two or more kinds.
[0030]
(Sealing material)
The material of the adhesive layer used for sealing the EL element is not particularly limited as long as it is soluble or dispersed in a solvent. Alternatively, it may be dispersed in a resin and dissolved in a solvent.
[0031]
(resin)
In the present invention, the resin means that the above material can be uniformly dispersed, and the above material may be dispersed by a dispersant or the like.
In the present invention, the EL layer, the insulating layer, the partition layer, the electrode, the sealing adhesive, and the like shown above may be frozen by a freezing method and formed into a film as long as they can be frozen.
[0032]
(solvent)
As a solvent for dissolving or dispersing the above-mentioned material, the above-mentioned material is dissolved or dispersed and solidified at a predetermined temperature, and a predetermined viscosity, solid content concentration, surface tension, boiling point, melting point, substrate surface, The solvent is not particularly limited as long as it is a contact angle and a solvent that can be dried.
[0033]
Specifically, water, alcohols such as methanol, ethanol, isopropyl alcohol, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone, hexamethylphosphoramide, benzene, toluene, xylene Isomers, trimethylbenzene isomers, tetramethylbenzene, tetralin, p-cymene, cumene, ethylbenzene, diethylbenzene isomers, butylbenzene, chlorobenzene, dichlorobenzene isomers, anisole, phenetole, butylphenyl Ether solvents such as ether, tetrahydrofuran, 2-butanone, 1,2-dioxane, diethyl ether, diisopropyl ether, diphenyl ether, dipentyl ether, diglyme, etc. , Chloro solvents such as dichloromethane, 1,1-dichloroethane, 1,2-dichloroethane, trichloroethylene, tetrachloroethylene, chloroform, carbon tetrachloride, 1-chloronaphthalene, cyclohexanone, etc. If it exists, two or more types of mixed solvents may be used.
[0034]
(Manufacturing method of EL element)
Finally, a general process flow when the present invention is applied to an EL element manufacturing method will be described.
a. The droplet of the organic EL material solution having a predetermined size is frozen and sieved to obtain a frozen product having the same amount and the same particle shape.
b. On the base material on which the electrode (ITO) is patterned, a layer for controlling the spread of the solution is formed on the portion other than the predetermined application portion by water repellent treatment.
c. The base material on which the electrode (ITO) is patterned is set to a predetermined temperature (a temperature at which the frozen material does not melt).
d. A frozen substance is placed on a predetermined application part (organic EL material).
e. The frozen material is melted and dried to remove the solvent.
f. After the organic EL layer is formed, a metal electrode is formed so as to cover the display region, and finally sealing for moisture prevention is performed to complete the EL element.
[0035]
【Example】
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
[0036]
Example 1
<Manufacture of frozen material for light emitting layer formation>
The polymeric fluorescent substance 1 was dissolved in xylene and adjusted to a solid content concentration of 1% by mass to prepare a light emitting layer forming solution 1. The light emitting layer forming solution 1 was dropped into liquid nitrogen and frozen. The frozen product was sieved to produce a spherical frozen product 1 having a predetermined size. Furthermore, the polymeric fluorescent substance 2 which shows the luminescent color different from the polymeric fluorescent substance 1 was dissolved in xylene and adjusted to a solid content concentration of 1% by mass to prepare a luminescent layer forming solution 2.
[0037]
The light emitting layer forming solution 2 was dropped into liquid nitrogen and frozen. The frozen material 2 was sieved to produce a spherical frozen material 2 having a predetermined size. Here, the polymeric fluorescent substance 1 indicates a luminescent material made of polyvinylcarbazole + coumarin derivative, and the polymeric fluorescent substance 2 shows a luminescent material made of polyvinylcarbazole + perylene derivative.
[0038]
<Production of frozen adhesive material for sealing>
The UV curable adhesive was dropped into liquid nitrogen and frozen. The frozen product was sieved to produce a spherical frozen product 3 of a predetermined size.
[0039]
<Manufacture of elements>
A polystyrene sulfonate / poly (3,4) ethylenedioxythiophene (PSS / PEDOT) film having a thickness of 100 nm was formed as a hole injection layer on a 25 mm square ITO film-formed glass substrate using a spin coater. Further, the substrate on which this film was formed was dried at 100 ° C. for 1 hour under reduced pressure to produce a substrate 1. The substrate 1 is set to a predetermined temperature (a temperature at which the spherical frozen materials 1 and 2 are not melted). The spherical frozen material 1 is placed at a predetermined position on the substrate using vacuum tweezers.
[0040]
Then, the spherical frozen material 2 using a light emitting material different from the spherical frozen material 1 is placed at a predetermined position on the substrate with vacuum tweezers. The frozen product was melted at room temperature and dried at 80 ° C. for 1 hour. As a result, on the 25 mm square ITO film-deposited glass substrate, layers having different emission colors were separately formed with a thickness of 5 mm × 5 mm and a film thickness of 100 nm. Further, a calcium film having a thickness of 5 nm was formed on this light emitting layer-coated substrate, and silver was vacuum-deposited thereon by 250 nm to produce a substrate 2. Thereafter, the substrate 2 is set to a predetermined temperature (a temperature at which the spherical frozen material 3 does not melt). The spherical frozen material 3 is arranged at a predetermined position around the light emitting region of the substrate 2 using vacuum tweezers. The frozen material was melted at room temperature, and a sealing glass (substrate 2) was placed thereon, and the adhesive was cured with ultraviolet rays, thereby manufacturing an EL device.
[0041]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of an element with high patterning precision can be provided in manufacture of various elements.

Claims (6)

In a method for manufacturing an element for forming a thin film on a substrate, the solution of the material constituting the thin film is frozen, the frozen material is placed in a desired region on the substrate, and then thawed to form a film. The manufacturing method of the element which does. The device manufacturing method according to claim 1, wherein droplets are formed from the solution, and the droplets are rapidly cooled and frozen into a spherical shape. The method for manufacturing an element according to claim 2, wherein the frozen product in a spherical shape is used after sieving. The manufacturing method of the element of any one of Claims 1-3 which form a recessed part in the said board | substrate surface, and arrange | position frozen material to this recessed part. The device manufacturing method according to claim 1, wherein the frozen material is disposed on a substrate through a pattern mask. The element manufacturing method according to claim 1, wherein the element is an EL element and the material is an organic light-emitting material.