JP2008226642A - Organic functional thin film heat treatment device, and manufacturing method of organic functional element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a high-quality and high-performance organic functional element by avoiding risk of crystallization and thermal deterioration when an organic functional thin film is subjected to an annealing treatment. <P>SOLUTION: This organic functional thin film heat treatment device is characterized by including: a substrate installation part installed in a chamber; a means of replacing the atmosphere in the chamber with an inert gas; a heating means arranged oppositely to the substrate installation part; and a substrate cooling means connected to the substrate installation part. This application also provides a formation method of an organic functional thin film characterized by including processes of: forming the organic functional thin film on a substrate; heating the organic functional thin film above a glass transition point temperature or a boiling point; and then cooling the organic functional thin film below the glass transition point temperature at a cooling rate not smaller than 10°C/min. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an organic functional thin film formed on a substrate and an element using the organic functional thin film.

In recent years, organic functional elements such as organic EL elements using organic functional materials, organic solar cells, and organic thin film transistors have been actively developed with the aim of reducing the weight and flexibility of electronic members. The organic functional material used for these organic functional elements is generally formed and used on a substrate as an organic functional thin film having a film thickness of about several tens to several thousand nm.

Examples of organic functional materials used for these organic functional thin films include low molecular weight materials and high molecular weight materials.

Low molecular organic functional thin films are often formed by resistance heating vapor deposition or the like. This is because a low molecular weight material is low in amorphousness and easily aggregates, and it is difficult to form a uniform amorphous organic functional thin film by the coating method.

On the other hand, since high molecular organic functional materials are highly amorphous, a method of forming a thin film using a wet process that uses organic functional materials dissolved or dispersed in a solvent is widely used. It has been. Examples of wet coating methods for forming a thin film include spin coating, bar coating, and dip coating. In particular, for high-definition patterning, it is considered that thin film formation by a printing method that specializes in painting and patterning is most effective (see, for example, Patent Document 1 and Non-Patent Document 1).

In any organic functional thin film, the aggregate state of the film is preferably an amorphous state. This is because if the material forming the thin film is a polycrystal, the thin film has many crystal grain boundaries and defects. As a result, defects such as leaks are likely to occur in the device, which is unstable. (See Non-Patent Document 2).

By the way, these organic functional thin films are often subjected to a heat treatment (annealing treatment) for the purpose of improving the film quality and improving the adhesion to the base. This is because, for example, when an organic EL element is made flexible, adhesion of each layer that can withstand deformation of the substrate and uniform light emission characteristics within the pixel are required. By applying the annealing treatment, it is expected that the film quality is improved by improving the adhesion at the interface between the layers and the amorphous property.

Since organic functional thin films generally react easily with oxygen and water, the annealing treatment is performed in an inert atmosphere such as an atmosphere replaced with nitrogen or argon or under vacuum. For this reason, the annealing treatment is performed in a glove box or an airtight chamber capable of reducing pressure and replacing gas. However, since it is advantageous in terms of productivity, it is often performed in an airtight chamber. A hot plate is widely used as a heating mechanism used in the chamber. Therefore, although the annealing temperature and time are controlled, there are many cases where the temperature rise and cooling profiles are not particularly controlled.

Organic functional thin films are often annealed around a glass transition temperature (Tg) (see Patent Document 2). In particular, when an organic functional thin film of a low molecular material is heated to Tg or more, crystallization is likely to occur, and it has been pointed out that the performance as an organic functional element is deteriorated (see Patent Document 3).

However, in view of the homogenization of the film thickness in the pixel and the adhesion between the substrate and each interface of the organic functional layer thin film, a higher heating temperature is considered preferable. For this reason, an organic functional material having a high glass transition temperature has been demanded, but a sufficient solution has not yet been made (see, for example, Patent Document 4). On the other hand, in terms of annealing treatment, no significant improvement has been made as a treatment method so far.

JP 2003-17261 A Japanese Patent Laid-Open No. 11-40352 JP-A-2005-310639 JP-A-9-205237 142th Committee C of Organic Materials for Information Science (Organic Optoelectronics) 5th Workshop Material Organic Thin-film Solar Cells by Printing Process (pages 20-27) Organic EL display, Shizushi Tokito et al., Ohm Corporation, 2004

The present invention has been made in view of the above circumstances, and manufactures high-quality and high-performance organic functional elements by avoiding the risk of crystallization and thermal degradation when annealing an organic functional thin film. The challenge is to make it possible.

First, as an invention related to an organic functional thin film heat treatment apparatus,
(1) Connected to the substrate installation part, the substrate installation part installed in the chamber, the means for replacing the atmosphere in the chamber with an inert gas, the heating means provided opposite the substrate installation part, and the substrate installation part And an organic functional thin film heat treatment apparatus comprising the substrate cooling means.
(2) In the organic functional thin film heat treatment apparatus of (1), the heating means is an infrared heater, and the substrate installation side surface of the substrate installation section has a reflectance of 80% with respect to the wavelength of infrared rays irradiated by the infrared heater. Consists of the above substances.
(3) Furthermore, the infrared rays irradiated from the infrared heater have a light energy peak at a wavelength of 3 to 25 μm.
(4) Moreover, a board | substrate cooling means should be spraying of the refrigerant | coolant to the said chamber exterior exposed surface of the said board | substrate installation part.

In addition, as an invention relating to a method for forming an organic functional thin film and an organic functional element,
(5) A step of forming an organic functional thin film on a substrate, a step of heating the organic functional thin film to a glass transition temperature or a boiling point or higher, and a glass transition temperature at a cooling rate of 10 ° C./min or higher. And a method of forming an organic functional thin film, comprising the step of cooling to:
(6) A step of forming a plurality of organic functional layers on the substrate, a step of heating above the glass transition temperature of the organic functional layer having the highest glass transition temperature or melting point among the organic functional layers, and 10 ° C. / and cooling to below the glass transition temperature of the organic functional layer having the lowest glass transition temperature among the organic functional layers at a cooling rate of min or more.
(7) In the manufacturing process of the organic functional element including the organic functional layer, at least one of the organic functional layers is formed by using the method for forming an organic functional thin film according to any one of claims 5 to 8. A method for producing a functional element.

According to the invention of (1), since the heat treatment is performed in a sealed inert gas atmosphere, deterioration of the organic functional material due to reaction with oxygen or water can be prevented, and the heating means and the cooling means are separately provided. Since the cooling means is directly connected to the substrate installation portion, rapid cooling is possible after heating. In particular, according to the invention of (4), an organic functional thin film heat treatment apparatus that can efficiently and uniformly cool the substrate by spraying the refrigerant and that can easily control the cooling time is obtained.

Furthermore, as shown in (3), an infrared heater is used as a heating means, and the infrared rays irradiated from the infrared heater have a light energy peak at a wavelength of 3 to 25 μm, so that the organic functional thin film is chemically changed. It is possible to heat efficiently without deteriorating effects such as damage and damage.

Further, according to the invention of (2), since most of infrared rays radiated from the infrared heater is reflected on the surface of the substrate installation portion, the substrate installation portion itself is not heated by infrared rays. Furthermore, since the transmitted infrared light is reflected also from the back surface of the substrate and is irradiated toward the substrate, the substrate can be efficiently heated.

In addition, the organic functional thin film is processed by the steps described in (5) to (7), and the organic functional thin film and the organic functional element are formed. For example, in an organic EL element, it is possible to manufacture an element having excellent element life and light emission characteristics. In addition, by heating above the glass transition temperature and further above the melting point, it becomes possible to obtain an organic functional thin film excellent in adhesion to the lower layer and flatness, and thus a high-quality organic functional element. It was.

Hereinafter, embodiments of the present invention will be described in detail.

(Organic functional thin film heat treatment equipment)
FIG. 1 shows an outline of an organic functional thin film heat treatment apparatus in the present invention. This apparatus has a cooling body 108 provided with an organic functional thin film carrying substrate 107 (hereinafter referred to as a substrate) and a heating body 106 facing the cooling body 108. In addition, the space including the substrate is installed in the annealing chamber 101 that can maintain an inert atmosphere so that the organic functional material on the substrate 107 does not cause an oxidation reaction when heated.

The annealing chamber 101 is connected to an exhaust valve 104 and an air supply valve 105 for replacement with an inert atmosphere such as nitrogen or argon. The atmosphere of the cooling chamber 102 is not particularly limited, but it needs to be designed so that the refrigerant does not leak.

Any heating element 106 may be used as long as it can heat the substrate 107 remotely, but a far-infrared heater capable of emitting infrared rays, particularly infrared rays having a light energy peak at a wavelength λ = 3 to 25 μm, is preferable. This is because many organic compounds have an absorber in that region, so that heating can be performed efficiently. Note that near infrared rays having a wavelength λ = 0.74 to 3 μm are likely to pass through the glass. Therefore, when glass is used for the substrate 107, the heating is not performed efficiently. Furthermore, when light having a short wavelength is used, it is not suitable because the organic compound is excited electronically and the organic functional thin film may be deteriorated.

The number and arrangement of the heating bodies 106 can be appropriately designed so that the substrate 107 is uniformly heated, and the positional relationship between the heating body 106, the substrate 107, and the cooling body 108 may not be as shown in FIG. . For example, the heating body can be a semi-cylindrical shape that covers the substrate, and can be shaped in consideration of heating efficiency.

The cooling body has both a substrate installation part and a substrate cooling part. As a matter of course, it is preferable to use a material having high thermal conductivity as the material constituting the cooling body 108. Moreover, it is preferable to use a substance having a reflectance of 80% or more with respect to the wavelength of infrared rays irradiated by the infrared heater at least on the surface of the cooling body on the substrate side. Reflecting most of the infrared rays radiated from the heating body on the surface of the cooling body, the cooling body is not heated, and the efficiency during cooling can be increased. This is because the infrared light reflected from the back surface of the substrate is irradiated toward the substrate, so that the substrate can be efficiently heated.

Examples of substances that satisfy the above two points include Ag, Al, Au, and Cu. Further, only the outermost surface of the cooling body 108 may be coated with such a substance. On the other hand, if the thickness of the cooling body 108 is too thin, it causes mechanical strength deficiency and heat non-uniformity. If it is too thick, it takes time for heat conduction, so that cooling with the refrigerant cannot be performed smoothly. Accordingly, although it depends on the material, the thickness is preferably about 1 to 50 mm.

As a method of cooling the substrate via the cooling body 108, a method of providing a water passage through which a heat exchange medium (refrigerant) passes in the cooling body or on the rear surface and allowing the refrigerant to flow therethrough is often performed. However, in order to uniformly cool a wide area of several tens of centimeters or more by this method, it is necessary to precisely control the flow of the refrigerant. In addition, since cooling is performed by moving the refrigerant, it is necessary to extract the refrigerant from the cooling body in order to stop the cooling. Therefore, there is a drawback in that switching of operation (ON / OFF of cooling) cannot be instantaneously performed.

Therefore, the present invention proposes a refrigerant spray method as a method for cooling the cooling body more simply and quickly. In this method, since the coolant is sprayed on the entire back surface of the cooling body, the cooling body can be uniformly cooled. Further, since the cooling by the spraying device is turned ON / OFF, the cooling time can be easily controlled.

The means for spraying the refrigerant is not particularly limited as long as the discharge amount of the refrigerant can be controlled and the refrigerant can be uniformly applied to the entire back surface of the cooling body. For example, one fluid spray nozzle or 2 A fluid spray nozzle can be used. The number and arrangement of the nozzles 109 can be appropriately designed so that the cooling body 108 is uniformly cooled.

The coolant 113 is not particularly limited as long as it does not corrode the cooling body 108, the coolant spray nozzle 109, and the chamber, and is liquid at the target cooling temperature, but has a flash point or ignition point or is toxic to the human body. Things should be avoided. Therefore, for example, water, liquid nitrogen, a nonflammable fluorine solvent, or the like is preferable.

The back surface of the cooling body 108 is exposed in the cooling chamber 102 because it is in contact with the coolant, but the surface carrying the substrate 107 is exposed on the annealing chamber 101 side. The end face of the cooling body 108 is tightly sealed so that the refrigerant 113 does not leak from the cooling chamber 102 side to the annealing chamber 101 side. Or you may make it comprise a cooling body by the whole chamber bottom face containing a board | substrate installation part. As described above, the cooling mechanism is exposed to both the inside of the chamber that can be replaced with a vacuum or an inert gas atmosphere and the portion to which the cooling mechanism is connected, so that the cooling mechanism itself can be configured at atmospheric pressure. Therefore, as described above, the substrate can be cooled by spraying the refrigerant, and the configuration of the cooling device is highly flexible.

The refrigerant 113 hitting the cooling body 108 is then collected in the collection tank by the refrigerant collection line 110, and after being re-cooled, it can be used again for spraying the refrigerant at the nozzle. As the recovery / recooling mechanism, a combination of a heat exchanger that cools the refrigerant, a filter that cuts off dust that causes nozzle clogging, and a pump that circulates the refrigerant may be appropriately selected and used. If a gaseous substance or a substance that does not need to be recovered in terms of cost and environment is used as the refrigerant in the operating environment of the apparatus such as liquid nitrogen, a recovery mechanism is naturally unnecessary.

(Method of forming organic functional thin film)
Next, a method for forming an organic functional thin film using the apparatus of the present invention will be described. The processing method of an organic functional thin film can be used for the element using organic functional materials, such as an organic EL element, an organic solar cell, an organic thin-film transistor, and each organic functional layer. For example, in the configuration diagram of the organic EL element as shown in FIG. 2, the charge transport layer 203a and the organic light emitting layer 203b correspond to the organic functional thin film in the present invention.

As described in the background art, organic functional materials can be broadly divided into low molecular weight materials and high molecular weight materials, but thin film deposition methods are also used separately depending on the type. . Mainly, dry processes such as vacuum deposition are used for low-molecular materials, and wet processes are used for polymer materials, which are coated with ink in which the material is dispersed or dissolved in a solvent.

As an example of the film forming process in the wet process, FIG. 3 shows an explanatory diagram of the relief printing method. A printing substrate 306 is fixed to the stage 307, the printing relief plate 304 patterned in accordance with the present invention is fixed to the plate cylinder 305, and the printing relief plate 304 is in contact with the anilox roll 303 which is an ink supply body. The anilox roll 303 includes an ink replenishing device 301 and a doctor 302.

First, ink is replenished from the ink replenishing device 301 to the anilox roll 303, and excess ink out of the ink 308 supplied to the anilox roll 303 is removed by the doctor 302. As the ink replenishing device 301, a dripping type ink replenishing device, a fountain roll, a slit coater, a die coater, a coater such as a cap coater, or a combination of these can be used. For the doctor 302, a known object such as a doctor roll can be used in addition to the doctor blade. The anilox roll 303 can be made of chromium or ceramics.

The ink 304 uniformly held by the doctor on the surface of the anilox roll 303 which is an ink supply to the printing relief plate is transferred and supplied to the projection pattern of the printing relief plate 306 attached to the plate cylinder 305. Then, as the plate cylinder 305 rotates, the convex pattern of the printing relief plate 306 and the substrate move relative to each other while being in contact with each other, and the ink is transferred to a predetermined position of the printing substrate 306 on the stage 308 and is transferred to the printing substrate. An ink pattern is formed.

Next is the annealing process. The physical properties of the low-molecular material and the high-molecular material change greatly near the glass transition temperature. It is said that there is.

When using low molecular weight materials, heat treatment at a temperature below the glass transition temperature results in an organic functional thin film with good characteristics due to the amorphous state, but at temperatures above the melting point, it is cooled to room temperature. As a result, it is known that the crystallized as a result, and the device lifetime and the light emission characteristics deteriorate. Therefore, as described in the background art, heating up to the glass transition temperature or higher or near the melting point has not been performed. However, the crystallized thin film is melted by heating up to the melting point, and in this state, it becomes an amorphous state because it becomes an amorphous state.

In addition, it has been reported that the drive life of the device is significantly improved by heat-treating a polymer organic functional thin film and annealing at a temperature higher than the glass transition temperature. The reason is that the film surface is smoothed by annealing treatment of Tg or more ("Effect of thermal annealing on the light of emitter light-emitting diodes", Jinok Kim et al., Appl. (2003)), the packing state of the polymer chain in the membrane is improved and the mobility is improved ("Hole and electrotransport in poly (9,9-dioxyfluorene9 and poly (9,9-dioctylfluorene-co-benzodi))". ", T. Kreouzis et al, Proc. Of SPIE 5214," 41-149 (2004) reference), and the like are mentioned.

From the above background, the organic functional thin film once heated to the glass transition temperature or above the melting point is in an amorphous state, and once the melting point is exceeded, the amorphous state becomes a good amorphous state with high smoothness and uniformity. It is considered that an excellent film surface is obtained and adhesion with the lower layer is improved.

Therefore, in the present invention, the organic functional thin film is heated to the glass transition temperature or higher, and further to the melting point or higher, and then rapidly cooled to maintain the state of the organic functional thin film. In particular, in the case of a low molecular weight organic functional layer thin film, since it is once dissolved, crystallization by heating at Tg or more does not become a problem. Furthermore, even after crystallization, a good amorphous film can be obtained by rapid cooling subsequent to heating above the melting point, so that it becomes possible to form a coating film that could not be easily formed by conventional crystallization. In addition, it is considered that a homogeneous film is also formed in the polymer material by randomizing the orientation of the functional group by heating to the glass transition temperature or higher.

As a specific process, after forming each layer, the annealing treatment of the present invention is performed as necessary. For example, after a low molecular weight material is formed by printing, the printed surface that has become non-uniform due to crystallization is once heated to a melting point or higher, and then melted at a cooling rate of 10 ° C./min or higher. A uniform amorphous surface can be obtained by rapidly cooling to a temperature below the transition temperature. If the cooling rate is high, crystallization is less likely to occur. However, if there is a risk that other materials constituting the substrate may be damaged by rapid cooling, or the difference in thermal expansion coefficient may be large, causing separation at the interface, the temperature of the refrigerant It is necessary to adjust the flow rate and the flow rate to the optimum speed.

In addition, a material having a very high melting point such as a polymer material and good film surface uniformity can obtain a sufficient annealing effect even if it is heated to Tg or more and less than the melting point and then cooled. . Even in such a case, since heating more than necessary may cause thermal degradation, it is preferable to cool the glass transition point temperature or lower at a cooling rate of 10 ° C./min or higher.

By these annealing treatments, the film quality and adhesion of the organic functional thin film are improved, and as a result, the device characteristics are improved. Moreover, when laminating | stacking a some organic functional thin film, it can also carry out for every organic functional thin film formation, and it is also possible to anneal-treat after forming each organic functional thin film. Although it is necessary to determine the process according to the characteristics of the organic functional material of each layer, when annealing is performed after forming a plurality of organic functional thin films, the glass transition temperature of the organic functional material thin film having the highest glass transition temperature Alternatively, it is preferable to heat to the melting point or higher and then rapidly cool to at least the glass transition temperature of the organic functional material thin film having the lowest glass transition temperature.

(Organic functional element and organic functional element manufacturing method)
As an example of the organic functional element, the organic EL element shown in FIG. However, as described above, the present invention relates to all objects having an organic functional thin film using an organic functional material, and is not limited to organic EL.

The substrate 201 used in the present invention is not limited as long as it is light-transmitting and has a certain degree of strength. Specifically, a glass substrate or a plastic film or sheet can be used. If a thin glass substrate having a thickness of 0.2 to 1 mm is used, a thin organic EL device having a very high barrier property can be produced.

The transparent conductive layer 202 is not particularly limited as long as it is a conductive material capable of forming a transparent or translucent electrode. Specifically, indium and tin composite oxide (hereinafter referred to as ITO), indium and zinc composite oxide (hereinafter referred to as IZO), tin oxide, zinc oxide, indium oxide, zinc aluminum composite oxide, and the like are included as oxides. However, ITO can be preferably used because of its low resistance, solvent resistance, transparency, and the like, and can also be formed on the translucent substrate 201 by vapor deposition or sputtering. Alternatively, a precursor such as indium octylate or indium acetone can be applied on a substrate and then formed by an application pyrolysis method in which an oxide is formed by thermal decomposition. Alternatively, a metal in which a metal such as aluminum, gold, or silver is vapor-deposited in a translucent state can be used. Alternatively, an organic semiconductor such as polyaniline can also be used.

The transparent conductive layer 202 may be patterned by etching as necessary, or may be activated by UV treatment, plasma treatment, or the like.

The organic functional layer 203 in the present invention may be a single layer or a stack of a plurality of functional layers. In the case of an organic EL element, it is necessary to provide at least an organic light emitting layer between the anode and the cathode. In addition, a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, etc. as functional layers The charge transport layer can be provided, and its configuration is arbitrary.

The material used for the charge transport layer 203a mainly provided adjacent to the transparent conductive layer 102 may be any material generally used as a hole transport material, such as copper phthalocyanine and its derivatives, 1,1-bis ( 4-di-p-tolylaminophenyl) cyclohexane, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4,4′-diamine (TPD), N , N′-di (1-naphthyl) -N, N′-diphenyl-1,1′-biphenyl-4,4′-diamine and other low molecular weight compounds such as aromatic amines, polyaniline derivatives, polythiophene derivatives, polyvinyl A polymer material such as a carbazole (PVK) derivative, a mixture of poly (3,4-ethylenedioxythiophene) and polystyrene sulfonic acid, or the like can be used. In addition, polyamines such as polyparaphenylene (PPP), polyarylene vinylenes such as polyphenylene vinylene (PPV), conductive polymers such as polyphenylene vinylene (PPV), or polymers such as polystyrene (PS), arylamines, carbazole derivatives, aryl A mixture of sulfides, thiophene derivatives, phthalocyanine-derived low molecular charge transporting materials, and the like may be used.

As a light emitter used for the organic light emitting layer 203b in the organic EL element, coumarin, perylene, pyrene, anthrone, porphyrene, quinacridone, N, N′-dialkyl-substituted quinacridone, naphthalimide, N, N Dissolve low-molecular-weight luminescent dyes such as' -diaryl-substituted pyrrolopyrrole, iridium complex, platinum complex, and europium complexes, and low molecular weight materials in polymers such as polystyrene, polymethyl methacrylate, and polyvinylcarbazole. Polymers that are copolymerized with polymers, polymer light emitters such as polyarylene, polyarylene vinylene, and polyfluorene can be used.

These materials may be formed by vapor deposition in the case of low molecules, but toluene, xylene, acetone, anisole, methylanisole, dimethylanisole, ethyl benzoate, methylbenzoate, mesitylene, tetralin, amylbenzene , Methyl ethyl ketone, Methyl isobutyl ketone, Cyclohexanone, Methanol, Ethanol, Isopropyl alcohol, Ethyl acetate, Butyl acetate, Water, etc. A single or mixed solvent used as a coating solution, spin coating method, curtain coating method, bar coating The film may be formed by a coating method such as a coating method, a wire coating method, a slit coating method, a letterpress printing method (flexographic printing method), an intaglio offset printing method, a letterpress reverse printing method, an ink jet printing method, an intaglio printing method. Possible A.

However, in order to display the organic EL element in full color, it is necessary to pattern the organic light emitting layer into three colors of R (red), G (green), and B (blue). Thus, when patterning an organic light emitting layer, it is preferable to use a printing method such as a relief printing method (flexographic printing method), an intaglio offset printing method, a relief printing reverse offset printing method, an ink jet printing method, and an intaglio printing method. In addition, organic light-emitting layers having different emission colors can be patterned for each pixel. In the organic EL element, the charge transport layer such as a hole transport layer or an electron transport layer is preferably patterned for each pixel in order to prevent current leakage to adjacent pixels. Also in this case, a printing method such as a relief printing method (flexographic printing method), an intaglio offset printing method, a relief printing reverse offset printing method, an ink jet printing method, and an intaglio printing method can be suitably used.

After forming each layer, the annealing treatment of the present invention is performed as necessary. For example, after a low molecular weight material is formed by printing, the printed surface that has become non-uniform due to crystallization is once heated to a melting point or higher, and then melted at a cooling rate of 10 ° C./min or higher. A uniform amorphous surface can be obtained by rapidly cooling to a temperature below the transition temperature. If the cooling rate is high, crystallization is less likely to occur. However, if there is a risk that other materials constituting the substrate may be damaged by rapid cooling, or the difference in thermal expansion coefficient may be large, causing separation at the interface, the temperature of the refrigerant It is necessary to adjust the flow rate and the flow rate to the optimum speed.

In addition, a material having a very high melting point such as a polymer material and good film surface uniformity can obtain a sufficient annealing effect even if it is heated to Tg or more and less than the melting point and then cooled. . Even in such a case, since heating more than necessary may cause thermal degradation, it is preferable to cool the glass transition point temperature or lower at a cooling rate of 10 ° C./min or higher.

By these annealing treatments, the film quality and adhesion of the organic functional thin film are improved, and as a result, the device characteristics are improved. This annealing treatment can be performed at an arbitrary timing in the organic functional element manufacturing process.

After forming the organic functional thin film, an electrode layer 205 composed of a cathode is formed on the organic functional layer 203. As the electrode layer, a single metal such as Mg, Al, Yb, Ba, or Ca is used, or a compound such as Li or LiF is sandwiched by about 1 nm at the interface in contact with the light emitting medium material. Cu can be laminated and used. Alternatively, in order to achieve both electron injection efficiency and stability, an alloy system of a metal having a low work function and a stable metal, for example, an alloy such as MgAg, AlLi, or CuLi can be used. As a method for forming the cathode, a resistance heating vapor deposition method, an electron beam method, or a sputtering method can be used depending on the material. The thickness of the electrode layer is desirably about 10 nm to 1000 nm.

Finally, in order to protect these organic functional laminates from external oxygen and moisture, a glass cap and an adhesive are hermetically sealed to obtain an organic EL element. Moreover, when a translucent board | substrate has flexibility, sealing sealing is performed using a sealing agent and a flexible film.

Hereinafter, although an organic EL element is mentioned as an example as an example of the present invention, the present invention is not limited to this.

(Example 1)
A glass substrate with ITO was prepared, and the ITO was etched into a predetermined pattern. Next, on the etched transparent conductive layer, a solution in which TPD (melting point: 170 to 171 ° C., glass transition point: 60 ° C.) was dissolved in toluene was applied in a pattern on the ITO substrate by a relief printing method to form a substrate 107. .
The film surface in the state where toluene was volatilized was cloudy due to crystallization.

This film surface was annealed by the apparatus shown in FIG.

The substrate 107 was placed in the annealing chamber 101, and nitrogen substitution was sufficiently performed so that the oxygen concentration in the chamber was 1 ppm and the dew point was −60 ° C.

Thereafter, the substrate 107 is heated with a far-infrared heater 106 until the surface temperature reaches 180 ° C., kept for 1 min, and sprayed with Solcan 365 mfc (manufactured by Solvay Japan) in which the copper cooling body 108 is cooled to −10 ° C. It cooled until the substrate temperature became 20 degreeC. The time required for each step of the heating step and the cooling step is 3 minutes for a substrate at room temperature (25 ° C.) to rise to 180 ° C., 2 minutes for cooling from 180 ° C. to 60 ° C., and 60 ° C. to 20 ° C. 1 min.

The obtained TPD film was a uniform transparent film having a thickness of 50 nm and a center line average roughness Ra of the film surface of 0.1 nm.

Alq3, lithium fluoride, and aluminum were formed on this substrate by vacuum deposition of 50 nm, 0.5 nm, and 200 nm, respectively, to obtain an organic EL element.

When a voltage of 6 V was applied to the obtained organic EL element, it showed patterned luminescence of 1000 cd / m2. Further, when the luminance half-life at the time of constant current driving was measured at an initial luminance of 1000 cd / m 2, the luminance half-life was 100 hr.

(Comparative Example 1)
A device was fabricated in the same manner as in Example 1 except that the annealing treatment was not performed after printing the TPD.

When voltage was applied to the obtained organic EL device, current flowed, but no light emission was confirmed. When the voltage was applied up to 15 V, the organic layer burned and the device was destroyed.

(Comparative Example 2)
A device was fabricated in the same manner as in Example 1 except that the TPD film was also formed by vacuum deposition and the annealing treatment was not performed.

When a voltage of 6 V was applied to the obtained organic EL element, it showed patterned luminescence of 1000 cd / m2. Further, when the luminance half-life at the time of constant current driving was measured at an initial luminance of 1000 cd / m 2, the luminance half-life was 50 hr.

(Example 2)
A glass substrate with ITO was prepared, and the ITO was etched into a predetermined pattern. Next, a liquid in which a mixture of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid was dispersed in water was applied in a pattern on the ITO substrate by letterpress printing on the etched transparent conductive layer. . This substrate was dried at 200 ° C. for 3 minutes in the air. The thickness after drying was 50 nm.

Further, poly (2- (2-ethylhexyloxymethoxy) -5-methoxy-1,4-phenylenevinylene) (glass transition temperature 196 ° C.), which is a polyarylene vinylene polymer light emitter, is dissolved in toluene, and a substrate is obtained. A substrate 107 was obtained by applying a pattern on the substrate by a relief printing method.

This film surface was annealed by the apparatus shown in FIG.

The substrate 107 was placed in the annealing chamber 101, and nitrogen substitution was sufficiently performed so that the oxygen concentration in the chamber was 1 ppm and the dew point was −60 ° C.

Thereafter, the substrate 107 is heated with a far-infrared heater 106 until the surface temperature reaches 200 ° C., and kept for 1 min. It cooled until the substrate temperature became 20 degreeC. The time required for each step of the heating step and the cooling step is 3 minutes for a substrate at room temperature (25 ° C.) to rise to 200 ° C., 2 minutes for cooling from 200 ° C. to 60 ° C., and 60 ° C. to 20 ° C. 1 min.

Lithium fluoride and aluminum were deposited on this substrate by vacuum deposition at 0.5 nm and 200 nm, respectively, to obtain an organic EL element.

When a voltage of 8 V was applied to the obtained EL element, it showed patterned luminescence of 100 cd / m2. Further, when the luminance half-life at the time of constant current driving was measured at an initial luminance of 100 cd / m 2, the luminance half-life was 3000 hr. Moreover, when the peeling test was done using the peelability evaluation method shown below (peelability evaluation method), the peel rate was 20%.

(Comparative Example 3)
A device was fabricated in the same manner as in Example 2 except that the phosphor thin film was not annealed. When a voltage of 8 V was applied to the obtained EL element, it showed patterned luminescence of 100 cd / m2. Further, when the luminance half-life at the time of constant current driving was measured at an initial luminance of 100 cd / m 2, the luminance half-life was 1500 hr. Moreover, when the same peeling test was conducted, the peeling rate was 70%.

(Peelability evaluation method)
The test in JIS K5400-1990 can be used for the adhesion at the surface of any organic functional thin film and the interface with the weakest adhesion among the interfaces below that layer. In particular, the cross-cut tape method adhesion test according to 8.5.2 is most suitable. However, since it is difficult to apply to the standard of the peelability of the thin film of the organic functional element under the conditions of the above test, some changes were made as follows.

First, the phosphor thin film of the substrate 107 that has been annealed was scratched with a cutter knife using a cutter guide with a 1 mm gap, and 100 grids were made in a 1 cm square, and 0.17 mN / mm on the surface. A 25 mm adhesive tape (No. 605 manufactured by Teraoka Seisakusho) was pressed with an eraser to be pasted and peeled off.

In JIS K5400-1990 8.5.1, the evaluation score of the cross cut test is evaluated from 0 points to 10 points depending on the state of scratches. However, for the evaluation of organic functional thin films, it is better not to use the point method, but to consider how many grids are peeled with respect to the total area of the grid, using the peel rate expressed by the area ratio. I concluded. That is,
(Peeling rate)% = (Peeled grid area) / (Cut grid area with adhesive tape) x 100
When the peel rate becomes 40% or less, the improvement in device characteristics was confirmed, and it was concluded that the annealing effect was sufficiently obtained.

It is sectional drawing of an example of the organic functional thin film heat processing apparatus in this invention. It is sectional drawing of an example of the organic functional element in this invention. It is explanatory drawing of the organic functional thin film formation method by a relief printing method.

Explanation of symbols

101 ... Annealing chamber 102 ... Cooling chamber 103 ... Power box 104 ... Exhaust valve 105 ... Air supply valve 106 ... Heating body 107 ... Organic functional thin film substrate 108 ... -Cooling body 109 ... Refrigerant spray nozzle 110 ... Refrigerant recovery line 111 ... Refrigerant recovery tank 112 ... Refrigerant transport pump 113 ... Refrigerant 201 ... Translucent substrate 202 ... Transparent conductive Layer 203 ... Organic functional thin film 203a ... Charge transport layer 203b ... Organic light emitting layer 204 ... Electrode layer 301 ... Ink replenisher 302 ... Doctor 303 ... Anilox roll 304 ... Ink 305 ... Plate cylinder 306 ... Printing relief 307 ... Printed substrate 308 ... Stage

Claims (9)

A substrate installation part installed in the chamber, a means for replacing the atmosphere in the chamber with an inert gas, a heating means provided opposite to the substrate installation part, and a substrate connected to the substrate installation part An organic functional thin film heat treatment apparatus comprising cooling means. The heating means is an infrared heater, and the substrate installation side surface of the substrate installation portion is made of a material having a reflectance of 80% or more with respect to the wavelength of infrared rays irradiated by the infrared heater. The organic functional thin film heat treatment apparatus according to claim 2. 3. The organic functional thin film heat treatment apparatus according to claim 1, wherein the heating means is an infrared heater, and the infrared ray irradiated from the infrared heater has a light energy peak at a wavelength of 3 to 25 μm. 4. The organic functional thin film heat treatment apparatus according to claim 1, wherein the substrate cooling means is spraying of a coolant onto the chamber external exposed surface of the substrate installation portion. Forming an organic functional thin film on the substrate;
Heating the organic functional thin film above the glass transition temperature; and
And a step of cooling to a glass transition temperature or lower at a cooling rate of 10 ° C./min or higher. Forming an organic functional thin film on the substrate;
Heating the organic functional thin film above the melting point;
And a step of cooling to a glass transition temperature or lower at a cooling rate of 10 ° C./min or higher. Forming a plurality of organic functional layers on the substrate;
The step of heating above the glass transition temperature of the organic functional layer having the highest glass transition temperature among the organic functional layers,
Next, the step of cooling below the glass transition temperature of the organic functional layer having the lowest glass transition temperature among the organic functional layers at a cooling rate of 10 ° C./min or more,
The manufacturing method of the organic functional thin film characterized by having. Forming a plurality of organic functional layers on the substrate;
Heating the organic functional layer having the highest melting point among the organic functional layers above the melting point of the organic functional layer;
Next, the step of cooling below the glass transition temperature of the organic functional layer having the lowest glass transition temperature among the organic functional layers at a cooling rate of 10 ° C./min or more,
The manufacturing method of the organic functional thin film characterized by having. In the manufacturing process of the organic functional element including the organic functional layer,
9. A method for producing an organic functional element, wherein the organic functional thin film forming method according to claim 5 is used for at least one organic functional layer.

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