JP2001323367A - Method for vapor depositing organic compound, and method for purifying organic compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for vapor depositing an organic compound with a high vapor deposition efficiency, in which the organic compound held in a container can be heated uniformly. SOLUTION: A container containing powder of an organic compound is heated in vacuum and the organic compound is vaporized or sublimated and deposited on a vapor deposition surface, by which thin film is deposited on the vapor deposition surface. In this method for vapor depositing the organic compound, the powder of the organic compound is mixed with a pulverulent or crushed body of at least one kind among ceramics, metal and ceramics-coated metal, and the resultant powder mixture is held in the container, and then the container is heated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for depositing an organic compound and a method for purifying an organic compound.

[0002]

2. Description of the Related Art As a method for forming an element having an organic compound thin film typified by an organic electroluminescent element (hereinafter referred to as an organic EL element), a heat evaporation method in a vacuum is generally adopted. . More specifically, for example, an organic compound powder is housed in a ceramic crucible having a filament wound on the outside, and the crucible is heated by energizing the filament to sublimate the organic compound inside to deposit a substance. This is a method of vapor deposition.

However, in such a vapor deposition method, since an organic compound having low thermal conductivity is heated from outside the crucible,
The heat does not reach the inside, the heat conduction to the organic compound in the crucible becomes non-uniform, and as the deposition proceeds, there are portions that are sublimated and portions that are not sublimated, resulting in poor sublimation efficiency and a decrease in the deposition rate. Was. In particular, the portion that is in contact with the inner wall may be excessively locally heated and thermally decomposed. When thermally decomposed, a decomposed product is mixed during film formation, which causes a reduction in device performance. further,
In view of mass production equipment, the capacity of the crucible is inevitably large, and the depth is larger than the opening diameter of the crucible, so as the organic compound decreases with time, the so-called chimney effect Since the organic compound molecules have directivity, it becomes impossible to form a uniform film on the surface to be deposited.
Therefore, conventionally, a lid having a plurality of holes is provided at the opening of the crucible to eliminate the directivity of organic compound molecules due to the chimney effect.

[0004] In the purification of organic compounds, a purification method is known in which an organic compound is contained in a crucible and heated as described above, and the sublimated or vaporized organic compound is cooled to extract only the organic compound. Have been. Also in this case, the heat conduction to the organic compound is not uniform, so the purification efficiency is poor, and the organic compound in the portion in contact with the inner wall portion of the crucible is thermally decomposed by excessive heating, and the decomposed product becomes an impurity. In some cases, it was mixed.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method for vapor-depositing an organic compound having a high vapor deposition efficiency, in which an organic compound contained in a container is heated substantially uniformly. Another object of the present invention is to provide a method for purifying an organic compound which can be purified with high efficiency and high purity.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method for heating and vaporizing or sublimating a container containing a powder of an organic compound by heating the powder of the organic compound with ceramics, metal, or metal coated with ceramics. It has been found that when mixed with a substance having high conductivity, ceramics, metal, or metal coated with ceramics can propagate heat to the inside and can be uniformly heated. There are embodiments of the method.

That is, according to the present invention, according to the aspect of the vapor deposition method, the container containing the powder of the organic compound is heated in a vacuum, and the organic compound is vaporized or sublimated and adhered to the surface to be vapor-deposited. An organic compound vapor deposition method for forming a thin film of an organic compound on the surface to be vapor-deposited, wherein the powder of the organic compound is formed of a ceramic, a metal, and a powder or a crushed body of at least one of metals coated with the ceramic. It is characterized in that the mixture is mixed and stored in a storage container, and the storage container is heated. Ceramics, metals, or metals coated with ceramics have higher thermal conductivity than organic compounds, and do not vaporize or sublime when the organic compounds vaporize or sublime.

According to an aspect of the present invention, there is provided a method for purifying an organic compound in which a container containing powder of an organic compound is heated to vaporize or sublime the organic compound and extract only the organic compound. In, the organic compound powder,
It is characterized in that it is mixed with at least one kind of powder or crushed body of ceramics, metal, and metal coated with ceramics, stored in a storage container, and the storage container is heated.

[0009] In any of the embodiments, an organic compound;
The mixing ratio with at least one of ceramics, metal, and metal coated with ceramic is 1: 5 by volume.
It is preferably 0 to 50: 1.

The particle size of the ceramic, metal, or metal powder coated with the ceramic is preferably 0.01 μm to 6 mm.

As the ceramic, a porous ceramic can be used. Further, the ceramic can be more specifically any one of a metal oxide, a metal nitride, a carbide, and carbon. For example, aluminum nitride, silicon carbide, and carbon can be used. The carbon is not particularly limited and various carbons can be used. Examples thereof include activated carbon, carbon black, and graphite. Of these, graphite having a high theoretical density is most preferable.

The present invention can be applied to vapor deposition or purification of an organic EL device. In this case, the organic compound is an organic EL device.
An organic compound used for forming an element. Further, the storage container can be a crucible or a boat.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the method for depositing an organic compound according to the present invention will be described. FIG. 1 shows an example of the configuration of a vapor deposition apparatus 10 for implementing the method of the present invention. This vapor deposition device 1
0 denotes a crucible (accommodating container) 12 for accommodating the evaporation material, a support member 15 for supporting the object 13 to be evaporated,
And a power supply 17. Among these, the vapor deposition container is formed by the container 11 and the lid 18, and the inside of the vapor deposition container is
During the vapor deposition, the vacuum is maintained by the vacuum pump 16.
The deposition material and the deposition target 13 are taken in and out by detaching the lid 18. The crucible 12 has a heating filament (heating wire) 14 connected to a power supply 17 wound around the outer periphery thereof. When the filament 14 is energized, it generates heat and heats the crucible 12. The above-described vapor deposition apparatuses are generally used and well known. In the present invention, the configuration of the vapor deposition apparatus itself does not matter.

As shown in FIG. 2, the crucible 12 contains an organic compound powder 18 and a ceramic powder 19 in a state of being stirred and mixed. The mixing ratio of the organic compound powder 18 and the ceramic powder 19 is not particularly limited, but is preferably 1:50 to 50: 1 by volume. As the organic compound to be deposited, a sublimable compound, a compound that evaporates through melting, a compound that evaporates while melting, or the like can be used. Ceramics that have higher thermal conductivity than the organic compound and that do not sublimate (evaporate) at a temperature at which the organic compound sublimates (vaporizes) are used.

In order to deposit an organic compound on the object 13, first, the vacuum pump 16 is operated to keep the inside of the vapor deposition apparatus 10 at a vacuum, and the crucible 12 is energized with the filament 14.
Heat. When the crucible 12 is heated, the internal organic compound powder 18 and the ceramic powder 19 are heated by the propagation of heat from the inner wall of the crucible 12. Since ceramics has a high thermal conductivity, the ceramic powder 19 heated near the inner wall of the crucible 12 propagates heat in a chain to the ceramic powder 19 at the center, and is moved away from the inner wall of the crucible 12. A certain ceramic powder 19 is also heated, and an organic compound powder 18 located around the ceramic powder 19 is also heated. When the temperature reaches a certain temperature, the organic compound powder 18 sublimates (vaporizes), adheres to and deposits on the object 13 to form a thin film. Ceramic powder does not change.

As described above, in this embodiment, the crucible 1 is prepared by mixing the organic compound powder 18 with the ceramic powder 19.
2, the ceramic powder 19 propagates heat from the inner wall of the crucible 12 to the central portion, and heats and uniformly sublimates (vaporizes) the whole of the contained organic compound powder 18. , And can be efficiently vapor-deposited. Since the organic compound powder 18 located near the inner wall of the crucible 12 is not overheated, thermal decomposition does not occur and the organic compound does not deteriorate. In addition, even when a crucible having a deep bottom is used during mass production, the effect of ceramics allows the entire organic compound in the crucible to be sublimated uniformly, so that the chimney effect can be prevented even when the amount of the organic compound decreases.

Next, an embodiment of the method for purifying an organic compound of the present invention will be described. FIG. 3 shows a tubular furnace 20 as a sublimation purification apparatus for performing the method of the present invention. As shown in the cross-sectional view of FIG. 4, the tubular furnace 20 is provided with a high-temperature filament 26a and a low-temperature filament 26b, which are formed in a cylindrical shape as a whole, and are arranged in the axial direction around the center hole 24. Depending on the organic compound to be purified,
For example, the high-temperature filament 26a is set to generate heat at a high temperature of about 300 ° C., and the low-temperature filament 26b is set to generate heat at a low temperature of about 150 ° C. A furnace tube 28 having openings 25 and 27 at both ends is inserted into the center hole 24 of the tubular furnace 20. The furnace tube 28 includes a plurality of transparent quartz tubes 28a to 28a.
8d are connected to each other, and the openings 2 at both ends are formed.
5 and 27 are formed in a small diameter. The core tube 28
An inert gas such as nitrogen or argon flows into the opening 25 and is exhausted from the opening 27. At the same time, the inside of the furnace tube 28 may be depressurized by forcibly sucking it from the opening 27 using a vacuum pump or the like.

To purify the organic compound, a boat (container) 30 containing an organic compound powder to be purified containing impurities is placed in a quartz tube 28a around which a high-temperature filament 26a is located, High temperature filament 26a
And the low-temperature filament 26b, and an inert gas is caused to flow in from the right end of FIG. This boat 30
Is heated from the outside by the high-temperature filament 26a, and as the temperature rises, the pure organic compound molecules to be extracted are sublimated (vaporized) and flow into an inert gas stream. Due to the temperature difference between the high temperature filament 26a and the low temperature filament 26b, there is a temperature gradient inside the furnace tube 28, and the sublimated (vaporized) organic compound solidifies when it reaches its freezing point and adheres to the inner wall of the quartz tube. Low temperature filament 26
Volatile impurities in the organic compound which evaporate even at the temperature of b are exhausted to the outside by the flow of the inert gas. In addition, non-volatile impurities in the organic compound that do not volatilize even with the high-temperature filament 26a remain in the boat 30. The purified organic compound is obtained by removing the quartz tube to which the organic compound has adhered and scraping out the organic compound attached to the inner wall.
The above-described purification using the tubular furnace 20 is generally performed and is well known.

In the method for purifying an organic compound according to the present invention,
As in FIG. 2 described above, the organic compound powder 18 and the ceramic powder 19 are stirred and mixed, accommodated in the boat 30, and similarly purified by the tubular furnace 20. Organic compound powder 1
Since the powder 8 is mixed with the ceramic powder 19 and stored in the boat 30, the ceramic powder 19 propagates heat from the inner wall portion of the boat 30 to the center, and the whole of the stored organic compound powder 18 is removed. Since the sublimation (vaporization) is performed by heating substantially uniformly, purification can be performed efficiently. In addition, since the organic compound located near the inner wall of the boat 30 is not overheated, thermal decomposition does not occur, and decomposition products as impurities do not mix.

In this embodiment, the organic compound powder and the ceramic powder are mixed in a powder state and stored in a crucible. However, both powders are mixed together with a solvent to form a slurry, and then dried to form a powder. A body may be used.

Further, in this embodiment, the purification apparatus using the tubular furnace is shown, but the organic compound is heated and sublimated (vaporized).
The present invention can be applied to other refining apparatuses as long as they are purified by refining.

The present invention is not limited to the type of ceramic mixed with the organic compound powder in both the above embodiments of the organic compound vapor deposition method and the organic compound purification method. Oxides, metal nitrides, carbides, carbon, for example, aluminum nitride, silicon carbide, carbon (for example, activated carbon, carbon black, graphite, preferably graphite having a high theoretical density) can be used. Further, instead of ceramics, metal or metal coated with ceramics may be used. Examples of metals that can be used include tantalum and tungsten. Metal coated ceramics
For example, it can be obtained by coating ceramics on the surface of metal particles by a technique such as CVD or sputtering. Any of ceramic, metal, and metal coated with ceramic can be mixed as a powder or a crushed body. The particle size is preferably 0.01 μm to 6 mm.

Further, in both embodiments, the crucible and the boat are exemplified as the container for accommodating the powder of the organic compound, but the form is not limited.

The method for vapor deposition of an organic compound according to the present invention, for example,
The present invention can be applied to vapor deposition of an organic compound in an organic EL device. As the organic compound, a hole injection layer and a hole transporting material, an electron injection layer and an electron transporting material, a substance which can be a light emitting material and a doping material, and the like can be used.
Each layer can be efficiently formed. Similarly, the method for purifying an organic compound can be applied to the purification of an organic compound used in an organic EL device.

[0025]

According to the present invention, it is possible to obtain a method for vapor-depositing an organic compound having a high vapor deposition efficiency, in which the organic compound contained in the container is heated substantially uniformly. Also, high efficiency,
A method for purifying an organic compound that can be purified with high purity can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an evaporation apparatus to which an evaporation method of the present invention is applied.

FIG. 2 is a cross-sectional view of a crucible containing an organic compound powder and a ceramic powder.

FIG. 3 is a perspective view showing an example of a sublimation purification apparatus (tubular furnace) to which the purification method of the present invention is applied.

FIG. 4 is a sectional view of the tubular furnace of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Evaporation apparatus 12 Crucible (container) 14 Filament 20 Tubular furnace 24 Center hole 26a High temperature filament 26b Low temperature filament 28 Core tube 30 Boat (Container)

Continued on the front page (72) Inventor Jun Endo 3 Kirihara-cho, Fujisawa-shi, Kanagawa Prefecture Inside A-Imes Corporation (72) Inventor Koichi Mori 3 Kirihara-cho, Fujisawa-shi, Kanagawa Prefecture A-Imes Corporation (72) Inventor Yokoi Kei 3 Kirihara-cho, Fujisawa-shi, Kanagawa Pref.

Claims (16)

[Claims] A container containing powder of an organic compound is heated in a vacuum to vaporize or sublimate the organic compound and adhere to the surface to be deposited, and a thin film of the organic compound is formed on the surface to be deposited. In the method of vapor-depositing an organic compound, the powder of the organic compound is mixed with at least one kind of powder or crushed material of ceramics, metal, and metal coated with ceramics, and the mixture is stored in the storage container. And heating the container. 2. The method according to claim 1, wherein the organic compound, the ceramic, the metal,
And at least one of metals coated with ceramics
A method for vapor deposition of an organic compound, wherein a mixing ratio with a seed is 1:50 to 50: 1 by volume. 3. The method according to claim 1, wherein the ceramic, metal, or metal powder coated with the ceramic has a particle size of 0.01 μm or more.
An organic compound vapor deposition method of 6 mm. 4. The method according to claim 1, wherein the ceramic is a porous material. 5. The method for vapor-depositing an organic compound according to claim 1, wherein the ceramic is:
An evaporation method of an organic compound selected from metal oxides, metal nitrides, carbides, and carbon. 6. The method according to claim 5, wherein the ceramic is an organic compound comprising aluminum nitride, silicon carbide or carbon. 7. The method for depositing an organic compound according to claim 1, wherein the organic compound is an organic compound used for forming an organic electroluminescent device. 8. The method for vapor deposition of an organic compound according to claim 1, wherein the container is a crucible or a boat. 9. A method for purifying an organic compound in which a container containing powder of an organic compound to be purified is heated to vaporize or sublime the organic compound and extract only the organic compound, Organic compound characterized by mixing powder with at least one kind of powder or crushed material of ceramics, metal, and metal coated with ceramic, storing the mixed powder in the storage container, and heating the storage container. Purification method. 10. The method for refining an organic compound according to claim 9, wherein a mixing ratio of the organic compound to at least one of the ceramics, the metal, and the metal coated with the ceramic is 1: 1: A method for purifying an organic compound which is 50 to 50: 1. 11. The method for refining an organic compound according to claim 9 or 10, wherein the particle diameter of the ceramic, metal, or metal powder coated with the ceramic is 0.01 μm.
A method for purifying an organic compound having a size of m to 6 mm. 12. The method for purifying an organic compound according to claim 9, wherein the ceramic is a porous body. 13. The method for purifying an organic compound according to claim 9, wherein the ceramic is any one of a metal oxide, a metal nitride, a carbide, and carbon. 14. The method for refining an organic compound according to claim 13, wherein the ceramic is aluminum nitride,
A method for purifying an organic compound comprising silicon carbide or carbon. 15. The method for purifying an organic compound according to claim 9, wherein the organic compound is an organic compound used for forming an organic electroluminescent device. 16. The method for purifying an organic compound according to claim 9, wherein the container is:
A method for purifying an organic compound which is a crucible or a boat.