JP2000017425A - Vessel for organic compound and fabrication of organic thin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an art capable of forming a uniform organic thin film on a substrate having a large diameter. SOLUTION: A vessel 10 for containing a material for an organic thin film is provided with receive holes 221-224 which are inclined from the center of the vessel 10 toward outer side and has a bottom. A vapor generated from the material for the organic thin film is allowed to have directivity toward the outside of the vessel 10 during flowing through each receive hole and uniformly released into a vacuum chamber. A uniform organic thin film can be formed on the substrate having larger diameter by adjusting the pressure to a prescribed pressure of 1.33×10-4-6.65×10-2 Pa by introducing gas into the vacuum chamber because the vapor released into the vacuum chamber comes into collision with the molecules of the gas and is scattered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum deposition technique, and more particularly to a container for containing an organic thin film material made of an organic compound, and a method for manufacturing an organic thin film by forming vapor from the organic thin film material. About.

[0002]

2. Description of the Related Art When organic compounds are compared with inorganic compounds, organic compounds have more diverse reaction systems and properties and can be surface-treated with low energy. I have.

There are various types using a functional organic thin film, such as an organic EL element, a piezoelectric sensor, a pyroelectric sensor, and an electric insulating film. Of these, the organic EL element can be used as a display panel. Has received a lot of attention.

[0006] Reference numeral a in FIG. 6 is a schematic configuration diagram of an organic EL device. An anode electrode film c made of a transparent conductive film, a P-type organic thin film d, and an N-type organic EL device are formed on a glass substrate b. A thin film e and a cathode electrode film f are formed in this order. When a voltage is applied between the anode electrode film c and the cathode electrode film f of the organic EL element a, the interface between the organic thin films d and e emits light, passes through the glass substrate b, and emits EL light g to the outside.
Can be emitted.

[0005] In order to form the organic thin films d and e, a vacuum evaporation method is generally used. An organic evaporation source is arranged in a vacuum chamber, vapor of the organic thin film material is discharged, and a film forming object is formed. An organic thin film can be formed by attaching it to the surface of a substrate.

[0006] However, the evaporation temperature of the metal material is 600 ° C.
While the temperature is as high as about 2000 ° C., the organic compound which is an organic thin film material has a high vapor pressure, and the evaporation temperature is usually between 0 ° C. (in some cases, below zero) and 400 ° C. Further, organic compounds are easily decomposed, and many of them are decomposed immediately when the decomposition temperature approaches the evaporation temperature and exceeds the evaporation temperature. Therefore, unlike a metal evaporation source, an organic evaporation source that emits a vapor of an organic thin film material needs a function capable of precisely controlling the temperature at a relatively low temperature.

Organic materials are often in the form of powder, but in vacuum, heat conduction is poor due to vacuum insulation between particles constituting the powder. And there is a problem that bumping is likely to occur. Therefore, it is difficult to convert a vacuum deposition apparatus suitable for forming an inorganic thin film such as a metal thin film to the formation of an organic thin film.

Therefore, in recent years, a dedicated vacuum deposition apparatus as shown by reference numeral 150 in FIG. 7 has been used to form an organic thin film. The vacuum deposition apparatus 150 will be described. The vacuum deposition apparatus 150 has a vacuum chamber 151, a substrate holder 130 is disposed on the ceiling side of the vacuum chamber 151, and an organic deposition source 140 is disposed on a bottom wall. Is provided.

Generally, organic thin-film materials are easily decomposed and cannot be heated by infrared rays, electron beams, or the like.
Inside, a container 110 in which a ceramic material such as graphite is perforated is disposed, and a heater 141 provided around the container 110 generates heat, and the organic thin film material accommodated in the container 110 is removed from the wall surface. It is configured to heat by heat conduction.

Referring to the plan view of FIG. 8 (a) and the sectional view taken along the line BB of FIG. 8 (b), an opening 212 is formed at the upper end of the container 110. The inside is surrounded by a cylindrical wall surface 211 from the opening 212 to a predetermined depth, and a cylindrical passage 221 is formed.

At the bottom of the passage 221, four deep-hole-shaped receiving holes 222 _{1 to} 222 ₄ are formed.
From 2 when dropped into the powdery organic film material and is configured such organic thin film material is housed in the housing hole 221 _{2-222 4.}

In such a container 110, the heater 141
When exothermed, organic thin film material contained in each containing hole 221 _{1-221 4} is other heat conduction from the wall 211, the heat conduction from the central portion 213 of the housing hole 221 _{1-221 4} since also heated by the entire organic thin film material is uniformly heated, from each containing hole 221 _1-221 within _4, toward the vacuum chamber 151, as the vapor of the organic thin film material is evenly released Has become.

When using the vapor deposition apparatus 150, the inside of the vacuum chamber 151 is previously set in a vacuum atmosphere, and the substrate holder 1
After mounting the substrate 131 on the substrate 30 and heating the substrate 131 by the heater 135 in the substrate holder 130, the evaporation source 1
The steam is generated from the inside.

After the generation of the vapor, the shutter 142 arranged near the opening of the organic vapor deposition source 140 is opened, and the vapor is released from the vacuum chamber 1.
51, and is attached to the film thickness monitor 143, and the vapor release rate is measured.

After the vapor of the organic thin film material is released stably, the shutter 1 disposed near the substrate 131
32 is opened, the vapor reaches the surface of the substrate 131, and the growth of the organic thin film is started.

The organic vapor deposition source 140 is connected to the vacuum chamber 15
If a plurality of the organic vapor deposition sources 140
The organic thin film substrate is released from the
By releasing the dopant from the substrate, an organic thin film having desired characteristics can be formed on the substrate 131.

In recent years, a display device using an organic EL element has been required to have a larger diameter. However, in the above-described container 110, as shown in FIG.
2 _1-222 steam 219 generated from the organic thin film material 225 in the ₄ will be directed is applied while raising the middle passage 221, can only be reached in a narrow range when released from the open outlet 121, the As a result, there is a problem that the organic thin film formed on the surface of the large-diameter substrate becomes uneven.

[0018]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages of the prior art, and has as its object to provide a technique capable of forming a uniform organic thin film on a large-diameter substrate. .

[0019]

According to a first aspect of the present invention, there is provided a container having a plurality of bottomed storage holes capable of storing an organic thin film material, wherein each of the storage holes is provided. When the vapor of the organic thin film material is generated within,
The portion in which the steam flows in each of the accommodation holes is inclined outward from the center of the container.

According to a second aspect of the present invention, there is provided the container according to the first aspect, wherein portions in which the steam flows in the accommodation holes are directed in different directions.

According to a third aspect of the present invention, there is provided the container according to any one of the first to second aspects, wherein an opening through which the vapor is discharged from the storage hole to the outside of the container is provided in the container. It is characterized by being inclined outward.

According to a fourth aspect of the present invention, there is provided the container according to any one of the first to third aspects, wherein each of the receiving holes is communicated with a lower portion.

According to a fifth aspect of the present invention, in the container according to the fourth aspect, a portion where each of the receiving holes communicates is arranged on a central axis of the container.

According to a sixth aspect of the present invention, there is provided a method for producing an organic thin film, wherein a vapor of an organic thin film material is generated in an organic vapor deposition source and released into a vacuum chamber to grow an organic thin film on a substrate surface. When discharging the vapor into the tank, a gas is introduced into the vacuum tank.

According to a seventh aspect of the present invention, the gas is introduced so that the inside of the vacuum chamber has a pressure range of 1.33 × 10 ⁻⁴ Pa to 6.65 × 10 ⁻² Pa. Features.

In the method according to the present invention, the container according to any one of the first to fifth aspects is disposed in the vapor deposition source, and the vapor is released from the opening of each of the accommodation holes. The method for producing an organic thin film according to claim 6, wherein:

[0027] The present invention is a container having a plurality of bottomed receiving holes which are configured as described above and whose upper end is open and whose lower end is closed. When a resistance heating means such as a micro heater is arranged around such a container, and the resistance heating means generates heat in a state where the organic thin film material is accommodated in each accommodation hole,
The organic thin film material is heated by heat conduction from the container wall, and the generated vapor is released from each of the storage holes.

Generally, the steam generated at the bottom of the accommodation hole is
When the steam is discharged from the opening at the upper end of the housing hole, the vapor passage in the housing hole gives directivity to the steam, and the diffusion after the air is released from the opening is limited by the “chimney effect”.

In the container of the present invention, the portion in which the steam flows in the accommodation hole is inclined outward from the center of the container, so that when the steam is released from the container, the steam flows out of the container. Released toward. Therefore, when a plurality of accommodation holes are provided, the vapor of the organic thin film material can reach a wide range and uniform even if the effect of the "chimney effect" is exerted, and a uniform organic thin film can be formed on the substrate surface. It is possible.

As the number of receiving holes increases, the uniformity improves, but the required number differs depending on the shape of the substrate on which the film is formed. When a rectangular substrate is used, four or more substrates are desirable. In the case of such a storage hole, if the portions through which the steam flows in the respective storage holes are directed in different directions, the steam is more uniformly discharged.

In the case of the above-described containers, the vapor discharged from each of the storage holes tends to overlap on the central axis of the container. Therefore, it is preferable that the opening of each accommodation hole is directed to the outside of the container so that the steam is discharged outward from the center of the container.

When the organic thin film material is accommodated in each accommodation hole, it is troublesome to accommodate the same amount individually. Therefore, when the respective accommodation holes are communicated with each other at the lower portion so that the organic vapor deposition material can be disposed at that portion, 1
It is preferable that the steam generated at each of the locations is discharged through each of the storage holes.

By the way, if the vapor of the organic thin-film material goes straight after being released into the vacuum chamber, it is considered that the spread in the vacuum chamber becomes narrow. Therefore, in the present invention, when growing an organic thin film, a gas that does not react with the vapor of the organic thin film material is introduced into the vacuum chamber, and the organic compound molecules constituting the vapor collide with the gas molecules to scatter the organic compound molecules. This allows the steam to reach a wider area.

In general, when a vapor is released from a vapor deposition source, the vapor spreads in a vacuum according to the cosine law. However, according to the calculation result, a container having four of the above-described accommodation holes is used, and nitrogen gas is introduced into the vacuum chamber. 0 × 10 ⁻⁴ Pa (6.0 × 10 ⁻⁶ Torr)
5 and the vapor was released,
Could of forming a film thickness organic thin film distribution as shown by the curve L ₁ in the graph (average growth rate 1.29Å / sec)). This curve L ₁ follows cos ^2.5 θ, but in the prior art container:
Since steam is released directly above, it becomes narrow distribution like the curve L ₂ in accordance with cos ¹² theta.

When a film thickness distribution of ± 10% is allowed for the organic thin film, a substrate having a diameter D ₁ can be used in the container of the present invention, whereas a diameter of about half that of the prior art container can be used. only board of D ₂ will not be able to use.

When gas is introduced into the vacuum chamber,
If the pressure is too low, the scattering effect is small, and if it is too
Since the amount of gas release is reduced and the film forming speed is reduced, 1.33 ×
10 ^-FourPa or more 6.65 × 10^-2Pressure range below Pa
Appropriate.

As described above, when the container of the present invention is used, the vapor is uniformly discharged into the vacuum chamber, and if the gas is introduced into the vacuum chamber at that time, the released vapor is scattered. Therefore, it is possible to form an organic thin film having a uniform film thickness distribution and characteristic distribution on the surface of a large-diameter substrate.

[0038]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for producing an organic thin film of the present invention will be described together with the container of the present invention. Reference is made to FIGS.
Numeral 0 is an example of the container of the present invention. The upper figure is a plan view, and the lower figure is a sectional view taken along line AA. FIG. 2 is a perspective view.

The container 10 has a cylindrical lower portion 17.
And a container body 1 composed of
One.

The container body 11 is made of opaque ceramics such as carbon graphite, silicon carbide, or carbon graphite coated with silicon carbide. Are to be united.

The bulging portion 18 is formed to have a larger diameter than the lower portion 17, and a flange 24 is provided around the bulging portion 18. Also, from the top of the bulging portion 18 toward the bottom 17 side, the four accommodating hole 22 _{1-22 4} is provided.

[0042] Each housing hole 22 _{1-22 4} the container body to a predetermined depth, are formed by drilling, its cross section is circular, the lower end portions _131-134 in a bottom, upper end is respectively open port 12 ₁ to 12 _4. Each opening port 12 ₁ to 12 _4, to be symmetrical with each other about the center axis 33 of the container 10 are arranged in the peripheral portion of the bulge portion 18 top.

[0043] Further, each of the lower end portion _131-134 is configured to communicate over the center axis 33, therefore, the central axis 321 _to 323 ₄ of the accommodation hole 22 _{1-22 4,} common It is inclined so as to spread outwardly towards the bottom 15 to an open port 12 ₁ to 12 _4.

The central axis 32 ₁ of the accommodation hole 22 _{1-22 4}
32 ₄ and the angle formed by the central axis 33 of the container 10 alpha, size and the substrate to be film-forming target, but also changes depending on the distance between the substrate and the container, in the container 10, the angle alpha of about 20 It has become a degree.

Each of the open ports 12 ₁ to 12 at the upper end of the bulging portion 18
12 ₄ are disposed portion is inclined, the release opening 12 ₁
12 ₄ in accordance with the inclination, which is inclined outward. Also, the diameter and depth of each of the accommodating holes 22 ₁ to 22 _4, as in the case of the angle alpha, the value is changed in relation to the substrate, in the container 10, the diameter of about 8 mm, depth of about 35mm Has become.

When using such a container 10,
The body-shaped organic thin film material is supplied to each ₁~ 12_FourDropped from
And put it in the bottom part 15 and attach it to the vapor deposition device in that state
Keep it.

Reference numeral 50 in FIG. 3 denotes a vapor deposition apparatus in that state. In a state where the container 10 is positioned by the flange portion 40 in a plurality of vapor deposition sources 40 provided on the bottom surface of the vacuum chamber 51, They are mounted one by one.

A vacuum exhaust system 45 and a gas introduction system 46 are connected to the vacuum chamber 51. When the vapor deposition device 50 is used, the vacuum exhaust system 45 is operated to evacuate the inside of the vacuum chamber 51 in advance. Keep it. After the inside of the vacuum chamber 51 reaches a predetermined pressure, the substrate 31 on which a film is to be formed is carried into the vacuum chamber 51 while maintaining the vacuum atmosphere.

A substrate holder 30 is provided on the ceiling side of the vacuum chamber 51, and the loaded substrate is mounted on the substrate holder 30. Reference numeral 31 indicates a mounted board. A heating element 41 composed of a micro heater is arranged around each container 10, and the micro heater 41 is energized to generate heat, thereby heating the organic thin film material stored in each container 10.

After the temperature of the organic thin film material is raised to a predetermined temperature and degassing is performed, a gas is introduced from the gas introduction system 46 into the vacuum chamber 51. This gas is desirably an inert gas such as argon gas or nitrogen gas which does not react with the organic thin film material.

After the pressure in the vacuum chamber 51 is increased to a predetermined pressure by introducing gas, the amount of electricity to the heating element 41 is increased, and the temperature of the organic thin film material in the container 10 is further increased. Here, it is assumed that two containers 10 in which an organic thin film material serving as a base material and an organic thin film material serving as a dopant are separately arranged are heated. It is known that the temperature at which vapor is generated from an organic thin film material is affected by the pressure of the atmosphere in which the organic thin film material is placed, in addition to the type of the organic thin film material.

Therefore, even when the temperature of the organic thin film material rises and reaches a temperature at which steam is generated in a vacuum atmosphere, when the organic thin film material is placed in a predetermined pressure atmosphere, no steam can be generated. .

In the case of manufacturing an organic thin film, after degassing, the organic thin film material is heated in a vacuum atmosphere to a temperature at which vapor is generated.
(Low vacuum) so that steam is not generated.

When the temperature of the organic thin film material is stabilized,
The introduction of gas is stopped, and the inside of the vacuum chamber 51 is evacuated.
33 × 10^-FourPa (1.0 × 10^-6Torr) or more 6.65 ×
10 ^-2Pa (5.0 × 10^-FourTorr)
When the pressure is reduced to
You.

At this time, the organic thin film material is placed in the accommodation hole 22 _1.
Is disposed to 22 ₄ of the common bottom section 15, generated steam, it flows an upper portion than the bottom 15 of the accommodation hole 22 ₁ to 22 _4, the traveling direction is directed to the outside of the container 10 in this state, it is radially emitted from the opening port 12 ₁ to 12 _4.

In this state, the shutter 42 provided above each vapor deposition source 40 is opened, and the released vapor is used as a film thickness monitor 43.
And the rate of vapor release is measured from the rate of vapor deposition. After the vapor is stably released from each of the evaporation sources 40 at a predetermined speed, the shutter 32 arranged near the substrate 31 is opened to allow the vapor of the organic thin film material to reach the substrate 31. Is started.

In the container 10 of the present invention, each of the receiving holes 22 ₁ to 22 _{1 is formed} .
22 ₄ and its opening port 12 ₁ to 12 _4, the center axis line of the container body 11 and is inclined outward. Reference numeral 19 in FIG. 4, the vapor released from the opening port 12 ₁ to 12 ₄ have the meanings indicated schematically Thus, steam 19, which is extensively released is scattered by collisions with the gas Therefore, when the film reaches the surface of the substrate 31 uniformly, an organic thin film having a good film thickness distribution can be formed on the surface of the large-diameter substrate 31.

In this case, the vapor of the organic thin film material serving as the base material of the organic thin film and the vapor of the organic thin film material serving as the dopant need to be uniform on the surface of the substrate 31. Even when the vapor is released from the substrate 40, each vapor uniformly reaches the surface of the substrate 31, so that an organic thin film having a uniform in-plane mixing ratio and film thickness can be formed.

It is also possible to arrange the same organic thin film material in each evaporation source 40, in which case an organic thin film having a desired thickness can be obtained in a short time.

[0060]

According to the present invention, an organic thin film having a uniform thickness can be formed on the surface of a large-diameter substrate.

[Brief description of the drawings]

FIG. 1 is a plan view of a container according to an example of the present invention and a cross-sectional view taken along line AA of FIG.

FIG. 2 is a perspective view of the container.

FIG. 3 is a vapor deposition apparatus equipped with the container of the present invention.

FIG. 4 is a view for explaining a state of steam released from the container of the present invention.

FIG. 5 is a graph for explaining a film thickness distribution of an organic thin film.

FIG. 6 is a diagram illustrating an organic EL element.

FIG. 7 is a view for explaining a vapor deposition apparatus using a container according to the related art.

8A is a plan view of a container of the prior art, and FIG. 8B is a sectional view taken along line BB of FIG.

FIG. 9 is a diagram for explaining steam released from a container according to the related art.

[Explanation of symbols]

10 Containers 12 _{1 to} 12 ₄ Open ports 22 ₁ to
22 ₄ … Accommodation hole 33… Central axis of container 40
…… Evaporation source 51 …… Vacuum tank

Claims (8)

[Claims] 1. A container having a plurality of bottomed accommodation holes capable of accommodating an organic thin film material, wherein when vapor of the organic thin film material is generated in each of the accommodation holes, The container, wherein a portion through which the vapor flows is inclined outward from a center of the container. 2. A part in which the steam flows in the accommodation hole,
The container of claim 1, wherein the container is oriented in different directions. 3. The container according to claim 1, wherein the opening through which the vapor is released from the housing hole to the outside of the container is inclined toward the outside of the container. The container as described. 4. The container according to claim 1, wherein each of the receiving holes communicates with a lower portion. 5. The container according to claim 4, wherein a portion where the storage holes communicate with each other is disposed on a central axis of the container. 6. A method for producing an organic thin film, wherein a vapor of an organic thin film material is generated in an organic vapor deposition source and released into a vacuum chamber to grow an organic thin film on a substrate surface, wherein the vapor is released into the vacuum chamber. A method for producing an organic thin film, wherein a gas is introduced into the vacuum chamber when performing the process. 7. A method for producing an organic thin film, wherein the gas is introduced so that the inside of the vacuum chamber has a pressure range of 1.33 × 10 ⁻⁴ Pa to 6.65 × 10 ⁻² Pa. . 8. The container according to claim 1, wherein the vapor is discharged from the opening of each of the storage holes. The method for producing an organic thin film according to any one of claims 6 to 7.