JP2012092396A - Vapor deposition method, and vapor deposition apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vapor deposition method in which impurities in a deposition material that has the getter action are prevented from depositing to a substrate or in a deposition film, the inside of a deposition chamber is made high vacuum in a short period of time, and the film deposition rate stability of vapor deposition in a short period of time after evacuation is achieved, and to provide a vapor deposition apparatus.SOLUTION: A dummy member 7 provided with at least a surface opposed to vapor deposition sources 4a and 4b is carried in the deposition chamber 1 during a process of evacuating the deposition chamber 1, a vapor deposition film of a prescribed thickness is formed on the dummy member 7, and then the vapor deposition to an actual substrate 2 is performed. Thus, the impurities emitted from the vapor deposition sources 4a and 4b and moisture that remains in the deposition chamber 1 are taken into the vapor deposition film deposited on the dummy member 7, the impurities that mix in the film deposited on the actual substrate 2 is reduced, and a time required to reach the pressure when the vapor deposition is performed on the actual substrate 2 is shortened.

Description

  The present invention relates to a deposition method and a deposition apparatus for forming a deposition material having a getter action on a substrate.

  The vapor deposition method is widely used as a method for forming a thin film necessary for various devices. In the vapor deposition method, deposition is performed on a substrate after the inside of the deposition chamber is set to a high vacuum in order to prevent impurities from being mixed into the film and to improve the stability of the deposition rate. In general, when depositing a material with a large getter action, such as magnesium oxide used as a protective film in plasma displays, the water pressure in the deposition chamber has a significant effect on the deposition rate. The film forming speed is not stable unless the water pressure is lowered. When such a material is used for mass production of products using the vapor deposition method, the exhaust time until reaching a high vacuum where the film formation speed is stable after maintenance of the vapor deposition system is greatly affected by productivity. Resulting in. Even in a low molecular type organic EL (electroluminescence) element that is currently being developed, various organic materials and inorganic metal materials are formed into a device by vacuum deposition. Some thin films also use materials with extremely large getter action, and the problem is to reduce the exhaust time after maintenance.

  In Patent Document 1, a volatile organic solvent is mixed into a carrier gas in a vacuum apparatus and introduced into a chamber, or a volatile organic solvent is introduced alone and evacuated to efficiently remove moisture. A vapor deposition method for quickly reaching a vacuum is disclosed.

  Patent Document 2 discloses a method of forming a semiconductor film on a substrate by proximity sublimation, which is one of vapor deposition methods. In Patent Document 2, a semiconductor film having a predetermined thickness is formed on a dummy substrate, a film having poor crystallinity mixed with impurities at the initial stage of deposition is formed, and then a semiconductor film is formed on the actual substrate to form a film having good crystallinity. The method of obtaining is proposed.

JP-A-6-99051 JP 2008-71961 A

  However, the vacuum apparatus of Patent Document 1 involves a risk because a volatile organic solvent is introduced. In some cases, the vapor deposition apparatus requires an explosion-proof structure, and thus there is a problem that costs are increased.

  The vapor deposition method of Patent Document 2 is a method for preventing impurities in the vapor deposition source material from adhering to the substrate. When a film is formed on an actual substrate, the previously formed dummy substrate is retained in the film formation chamber. Alternatively, the deposition chamber is opened to the atmosphere, and the dummy substrate and the actual substrate are exchanged. Therefore, it is possible to prevent the impurities in the deposition source material from adhering to the substrate, but it is impossible to achieve deposition rate stability in deposition by reaching the high vacuum in the deposition chamber in a short time. In addition, since the dummy substrate and the shield stay in the film formation chamber, depending on the material, re-detachment of moisture and impurities from them may cause a problem.

  The object of the present invention is to prevent impurities in the vapor deposition material from adhering to the substrate and the deposited film, to reach a high vacuum in the deposition chamber in a short time, and to deposit the deposition rate in a short time after evacuation. It is to provide a vapor deposition method and a vapor deposition apparatus that realize stability. In other words, it is to provide a vapor deposition method and vapor deposition apparatus that can be used for mass production and that can provide good device characteristics.

A first aspect of the present invention is a vapor deposition method for forming a thin film of a material having a getter action on a substrate.
When the film formation chamber is opened to the atmosphere,
Evacuating the film formation chamber to a first pressure;
Throwing a dummy member having at least a surface facing the vapor deposition source into the film formation chamber, and forming a vapor deposition film having a predetermined thickness;
Evacuating the film formation chamber until a second pressure is reached after removing the dummy member from the film formation chamber;
Placing a real substrate into the film formation chamber and forming a thin film on the real substrate;
Are performed in the above order.

A second aspect of the present invention is a vapor deposition apparatus for forming a thin film of a material having a getter action on a substrate.
A deposition chamber with a deposition source;
A dummy member having at least a surface facing the vapor deposition source;
Means for allowing the dummy member to be loaded and unloaded without opening the film formation chamber to the atmosphere.

  In the present invention, when the film formation chamber is opened to the atmosphere, in the process of evacuating the film formation chamber to a predetermined pressure, the vapor deposition material is heated to form a film on the dummy member. After exhausting until the pressure is reached, film formation is performed on the actual substrate. Thereby, a vapor deposition film containing impurities released from the vapor deposition material in the initial stage of heating is deposited on the dummy member, and the adhesion of impurities to the surface of the actual substrate and the film deposited on the actual substrate is prevented. In addition, moisture remaining in the film formation chamber can be efficiently taken into the film deposited on the dummy member, and the pressure at which film formation on the actual substrate can be started from the start of exhaust can be reached in a short time. Yes. Therefore, according to the present invention, the contamination of impurities on the surface of the actual substrate and the film formed on the actual substrate is extremely reduced, and good device characteristics can be obtained, and the start-up exhaust time after equipment maintenance is greatly shortened. It becomes possible to improve mass productivity.

It is sectional drawing which shows typically one Embodiment of the vapor deposition apparatus of this invention, and a perspective view of a dummy member. It is sectional drawing which shows typically other embodiment of the vapor deposition apparatus of this invention.

The vapor deposition method and vapor deposition apparatus of the present invention relates to a method and apparatus for vapor depositing a material having a getter action (action to absorb moisture), and when vapor deposition is started again after the vapor deposition apparatus is opened to the atmosphere, the following steps are performed. It has the following order.
A step of evacuating the film formation chamber until the first pressure is reached. A step of introducing a dummy member having at least a surface facing the vapor deposition source into the film formation chamber to form a vapor deposition film having a predetermined thickness. A step of removing the dummy member from the film formation chamber and then evacuating the film formation chamber until the second pressure is reached; a real substrate is put into the film formation chamber and a thin film is formed on the real substrate Forming Steps Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Embodiment 1>
FIG. 1A is a cross-sectional view schematically showing the main configuration of one embodiment of the vapor deposition apparatus of the present invention, in which 1 is a film forming chamber, 6 is a mask stock chamber, and 8 is a transfer chamber. . A vacuum pump (not shown) is connected to each chamber individually, and the atmosphere can be completely shut off by the gate valves 9 and 10. FIG. 1B shows a state where the actual substrate 2 and the mask 3 are taken out from the film forming chamber 1 and a dummy member 7 is put into the film forming chamber 1. In the present invention, the “real substrate” means a film formation substrate on which original vapor deposition is performed. Usually, the actual substrate 2 is a glass substrate.

  In the vapor deposition apparatus of this example, vapor deposition sources 4a and 4b are arranged in the film forming chamber 1, and have a structure that allows so-called co-vapor deposition of different materials at the same time. A main shutter 5 is disposed between the vapor deposition source 4a and the vapor deposition source 4b and the actual substrate 2 to control the start and end of film formation on the actual substrate 2 and when the actual substrate 2 and the mask 3 are exchanged. The deposition particles are prevented from being deposited on a mechanism that holds the actual substrate 2 (not shown).

  The film forming chamber 1 has a structure in which the actual substrate 2, the mask 3 and the dummy member 7 can be loaded / unloaded independently and each member can be positioned at a predetermined position. The actual substrate 2 is transported by a robot (not shown) in the transport chamber 8 and can be transported between the film forming chamber 1 and a load chamber and other process chambers (not shown). The mask 3 is transported between the film forming chamber 1 and the mask stock chamber 6 by a roller transport mechanism (not shown) in the film forming chamber 1 and the mask stock chamber 6. The dummy member 7 is transported between the film forming chamber 1 and the mask stock chamber 6 by a roller transport mechanism (not shown) in the film forming chamber 1 and the mask stock chamber 6 in the same manner as the transport of the mask 3. .

  FIG. 1C is a perspective view of the dummy member 7 of this example, and the direction indicated by the arrow A in the drawing corresponds to the direction indicated by the arrow A in FIG. The dummy member used in the present invention only needs to have at least a surface facing the vapor deposition source. In this example, in addition to the flat top plate facing the vapor deposition sources 4a and 4b, it has four side surfaces and covers the space in the film forming chamber. In order to prevent collision with the vapor deposition sources 4a and 4b during transport from the mask stock chamber 6, the lower portion of the side surface on the transport chamber 8 side is omitted. The material of the dummy member 7 is not particularly limited, but is preferably aluminum, stainless steel or the like that is lightweight and can maintain strength. For example, SUS304 is preferably used. As the dummy member 7, it is preferable that the surface area be as large as possible in order to efficiently incorporate moisture remaining in the deposition chamber 1 by depositing a vapor deposition film into the deposited film. Therefore, it is preferable to blast or emboss the inner surface of the dummy member 7 as well as increase the size.

  Further, when the vapor deposition film is deposited with the dummy member 7 in a low temperature state, the efficiency of moisture incorporation into the deposited film is improved. Therefore, in this example, means for cooling the dummy member 7 in the mask stock chamber 6 (not suitable) (Shown) is provided. Specific examples of such cooling means include a structure in which a cooling block filled with a cooling medium is pressed against the upper surface of the dummy member 7 for cooling.

  As an operation in this example, first, the film formation chamber 1 is evacuated until the first pressure is reached. When the inside of the film forming chamber 1 reaches the first pressure, the dummy member 7 cooled by the cooling mechanism in the mask stock chamber 6 is put into the film forming chamber 1, and the vapor deposition sources 4a and 4b are set to a desired film forming speed. Is heated to a temperature at which is obtained. When the vapor deposition sources 4a and 4b reach a predetermined temperature, deposition of the vapor deposition film on the dummy member 7 is started. When the deposited film on the dummy member 7 reaches a predetermined thickness, the main shutter 5 is closed and the dummy member 7 is taken out from the film forming chamber 1 to the mask stock chamber 6. Next, the inside of the film forming chamber 1 is evacuated until it reaches the second pressure. When the inside of the film forming chamber 1 reaches the second pressure, the actual substrate 2 is put into the film forming chamber 1 and the mask 3 is mounted. Attach to the substrate 2. Next, the main shutter 5 is opened to start film formation on the actual substrate 2. In the present invention, the first pressure> the second pressure, and the second pressure is a pressure at the time of film formation on the actual substrate. In addition, as the thickness of the film deposited on the dummy member 7, an experiment is performed in advance, and a thickness at which impurities released from the vapor deposition material in the initial stage of heating and moisture in the film formation chamber 1 can be sufficiently taken in is measured. Set it.

  The material having a getter function used as a vapor deposition material in the present invention is not particularly limited. For example, magnesium oxide or barium oxide having a large getter function, cesium carbonate that is a constituent material of an electron injection layer of an organic EL element is preferable. Can be mentioned. Moreover, Al etc. which are used as a cathode of an organic EL element are also mentioned.

  Further, the vapor deposition apparatus of the present invention includes a process chamber other than the film formation chamber 1, and in such a process chamber, a film formation process such as vapor deposition using a material other than the material having a getter function according to the present invention, or other than film formation The substrate processing step may be performed.

<Embodiment 2>
FIG. 2A is a cross-sectional view schematically showing the main configuration of the second embodiment of the vapor deposition apparatus of the present invention. The difference from the first embodiment is that the shape of the dummy member is a flat plate. . FIG. 2B shows a state where the actual substrate 2 and the mask 3 are taken out from the film forming chamber 1 and a dummy member 27 is put into the film forming chamber 1. In this example, a glass substrate similar to the actual substrate 2 can be used as the dummy member 27.

  In FIG. 1 and FIG. 2, the dummy member 27 is introduced from the mask stock chamber 6 into the film forming chamber 1, but the present invention is not limited to this configuration. The dummy member 27 may be loaded from a load chamber (not shown) for loading the actual substrate 2 into the apparatus, and transported into the film forming chamber 1 by a transport mechanism for the actual substrate 2 (not illustrated). Then, after a film having a desired thickness is deposited in the film forming chamber 1, the film is transferred to an unload chamber (not shown) by the transfer mechanism of the actual substrate 2, vented, and taken out from the apparatus.

  In the present invention, the number of vapor deposition sources arranged in the film forming chamber 1 is not limited, and a plurality of vapor deposition sources can be arranged. Various types such as a heater heating type, an induction heating type, and a resistance heating type can be used as the evaporation source, and there is no particular limitation. Further, it is possible to provide a mechanism for cooling the dummy member 7 in the film forming chamber 1.

Example 1
After maintaining the film forming chamber 1 with the vapor deposition apparatus illustrated in FIG. The production flow is as follows.

The phenanthroline compound material was set in the vapor deposition source 4a in the film forming chamber 1 and the cesium carbonate material was set in the vapor deposition source 4b. When the pressure in the film forming chamber 1 reaches 7 × 10 ⁻⁴ Pa (first pressure), the gate valve 10 is opened, and the dummy member 7 which has been put into the mask stock chamber 6 and evacuated and cooled is removed. Then, the film was transferred to the film forming chamber 1 and set. Immediately after 7 dummy members were set, heating of the vapor deposition sources 4a and 4b was started, and the temperature was raised until a desired film formation rate was obtained. The main shutter 5 was closed when the total film thickness deposited on the actual substrate 2 reached about 1.0 μm with a quartz vibration type vapor deposition monitor, the gate valve 10 was opened, and the dummy member 7 was transferred to the mask stock chamber 6.

While the film formation chamber 1 is continuously evacuated, the inside of the film formation chamber 1 reaches a desired ultimate pressure of 1 × 10 ⁻⁴ Pa (second pressure), and then the mask 3 is transferred from the mask stock chamber 6. The film was set in the film formation chamber 1 (preparation for film formation in the film formation chamber 1 was completed). In addition, before the film formation chamber 1 is ready for film formation, the actual substrate 2 on which a thin film transistor, a lower electrode, and a partition wall are formed on a glass substrate is introduced into the vapor deposition apparatus from the load chamber, and the normal process chamber 2 is properly processed in another process chamber. A hole transport layer, a light emitting layer, and an electron transport layer were formed.

  After the film formation chamber 1 is ready for film formation, the actual substrate 2 on which the hole transport layer, the light emitting layer, and the electron transport layer are formed in another process chamber is opened to the film formation chamber 1 by opening the gate valve 9. And set on the mask 3. The main shutter 5 was opened, an electron injection layer having a desired film thickness was formed on the actual substrate 2, and then the main shutter 5 was closed. After forming the electron injection layer, the gate valve 9 was opened, and the actual substrate 2 was transferred to another process chamber to form a cathode layer. Further, the actual substrate 2 was transferred to another process chamber and sealed with glass. And the real board | substrate 2 complete | finished to glass sealing was conveyed to the unload chamber, and after taking out from the vapor deposition apparatus, it transferred to the cutting device and cut | disconnected for every panel.

  The light emission characteristics of the obtained organic EL element were evaluated with a light emission evaluation apparatus. As a result, there was no adhesion of impurities to the interface between the electron transport layer and the electron injection layer and to the electron injection layer, and good emission characteristics with high brightness and long life were obtained.

  In the manufacturing flow of this example, the time from when the vacuum exhaust in the film forming chamber 1 is started until the actual substrate 2 can start forming a film (the inside of the film forming chamber 1 reaches the second pressure) is 4 hours. Thus, film formation on the actual substrate 2 could be started in a short time after the end of the maintenance.

(Example 2)
An organic EL panel was produced under the same conditions as in Example 1 except that the flat dummy member 27 illustrated in FIG. 2A was used as the dummy member 7.

In this example, the time from when the film forming chamber 1 is evacuated until the actual substrate 2 can start film formation (the inside of the film forming chamber 1 reaches the second pressure 1 × 10 ⁻⁴ Pa) is 6 hours. It was time, and the film formation on the actual substrate 2 could be started in a short time after the maintenance was completed. Compared to the first embodiment, the time from the start of the evacuation of the deposition chamber 1 to the start of the deposition of the actual substrate 2 is increased because the surface area of the dummy member 27 is the dummy surface of the first embodiment. This is because the amount of water that is smaller than that of the member 7 and can be taken into the deposited film is reduced.

  In addition, the organic EL panel produced in this example did not have impurities attached to the interface between the electron transport layer and the electron injection layer and to the electron injection layer, and good emission characteristics with high luminance and long life were obtained.

(Example 3)
An organic EL panel was produced under the same conditions as in Example 2 except that the dummy member 27 was not cooled in advance.

  In this example, the time from the start of the exhaust of the film forming chamber 1 until the actual substrate 2 can start film formation (the inside of the film forming chamber 1 reaches the second pressure) is 7 hours, and the maintenance is completed. After a short time, film formation on the actual substrate 2 could be started. Compared to the second embodiment, the time from the start of the evacuation of the deposition chamber 1 to the time when the deposition of the actual substrate 2 can be started is increased because the dummy member 27 was not cooled in advance. Is.

  In addition, the organic EL panel produced in this example did not have impurities attached to the interface between the electron transport layer and the electron injection layer and to the electron injection layer, and good emission characteristics with high luminance and long life were obtained.

(Comparative Example 1)
An organic EL panel was manufactured under the same conditions as in Example 1 except for the following conditions.

  The dummy member 7 was not put into the film forming chamber 1, and after evacuating until the film forming chamber 1 reached the second pressure in Example 1, heating of the vapor deposition sources 4a and 4b was started. Immediately after the deposition sources 4a and 4b were heated, the pressure in the film forming chamber 1 was increased by the gas release from the deposition sources 4a and 4b and the surroundings, and greatly exceeded the second pressure. Therefore, after the desired film formation speed is obtained, the inside of the film formation chamber 1 is evacuated as it reaches the second pressure, and then the mask 3 is transported and set from the mask stock chamber 6 to form the actual substrate 2. It was conveyed to the film chamber 1 to form an electron injection layer.

  In this example, it took 6 hours from the start of evacuation of the film forming chamber 1 to the second pressure before heating the vapor deposition source. Moreover, it took 8 hours until the second pressure was reached again after heating the vapor deposition source. In other words, it took 14 hours to exhaust the gas from the end of the maintenance to the pressure at which the film formation on the actual substrate 2 was started.

  In addition, in the characteristics of the organic EL panel produced in this example, there was no impurity adhesion to the interface between the electron transport layer and the electron injection layer and to the electron injection layer, and good emission characteristics with high brightness and long life were obtained. .

(Comparative Example 2)
After starting the heating of the vapor deposition sources 4a and 4b, the mask 3 and the actual substrate 2 are placed in the film forming chamber immediately after a desired film forming speed is obtained without waiting for the inside of the film forming chamber 1 to reach the second pressure. The organic EL panel was manufactured under the conditions of Comparative Example 1 except that the electron injection layer was formed. The pressure in the film formation chamber 1 at the start of film formation on the actual substrate 2 was 7 × 10 ⁻⁴ Pa.

  The characteristics of the organic EL panel fabricated in this example are that impurities released from the evaporation source and moisture released from the surroundings due to the radiation of the evaporation source are mixed into the interface between the electron transport layer and the electron injection layer and the electron injection layer. As a result, the drive voltage increased and the service life decreased.

  1: deposition chamber, 2: actual substrate, 4a, 4b: vapor deposition source, 7: dummy member

Claims (3)

In a vapor deposition method for forming a thin film of a material having a getter action on a substrate,
When the film formation chamber is opened to the atmosphere,
Evacuating the film formation chamber to a first pressure;
Throwing a dummy member having at least a surface facing the vapor deposition source into the film formation chamber, and forming a vapor deposition film having a predetermined thickness;
Evacuating the film formation chamber until a second pressure is reached after removing the dummy member from the film formation chamber;
Placing a real substrate into the film formation chamber and forming a thin film on the real substrate;
Are performed in the above order. In a vapor deposition apparatus for forming a thin film of a material having a getter action on a substrate,
A deposition chamber with a deposition source;
A dummy member having at least a surface facing the vapor deposition source;
Vapor deposition apparatus comprising means for allowing the dummy member to be loaded and unloaded without opening the film formation chamber to the atmosphere.   The vapor deposition apparatus of Claim 2 provided with the means to cool the said dummy member.

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