JP3791450B2 - Deposition method of organic thin film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an organic thin film deposition method for forming an organic thin film on a substrate surface as a film forming object.
[0002]
[Prior art]
In recent years, the speed of information communication and the application range have been rapidly increasing. Among these, inventions and devices for high-definition display devices having low power consumption and high-speed response that can meet the demands of portability and moving image display have been widely used for display devices. .
[0003]
The organic electroluminescence (organic EL) element has been reported since Tang et al. (Appl. Phys. Lett., 51,913 (1987)), a report on a stacked EL element that emits light with high luminance of 1000 cd / m ² or more at an applied voltage of 10 V In terms of high contrast, low voltage drive, high viewing angle, high-speed response, etc., it is expected to be applied to the display device, particularly a flat panel display, as having characteristics superior to liquid crystal display elements, etc. Research for practical application is actively conducted. Green monochrome organic EL displays and the like have already been commercialized, and the completion of high-definition full-color displays is awaited.
[0004]
Despite these circumstances, conventional vacuum deposition equipment and mechanisms for forming conventional metal and inorganic thin films have been diverted to the formation of conventional organic thin films, making them suitable for organic thin film formation. A practical vapor deposition apparatus and vapor deposition method have not been developed so much.
[0005]
FIG. 3 is a conceptual schematic configuration diagram of a conventional organic thin film deposition apparatus. In FIG. 3, 11 is a vacuum chamber configured to be evacuated, 18 is a substrate for forming an organic thin film, 12 is a substrate holder, 15 is an evaporation source of the organic material, 16 is the surface of the evaporation material, and 17 is in the vacuum chamber. A viewing window for observation, 19 is a deposition preventing plate for preventing the deposition material from adhering to the viewing window, 23 is an evaporation shutter, and 22 is a film thickness monitor for measuring an organic thin film formation speed. Although not shown in FIG. 3, a load lock chamber for stocking a substrate for forming an organic thin film is usually provided, and the substrate is transferred from the load lock chamber to a vacuum chamber 11 via a transfer means such as a transfer rod or a vacuum robot. It is configured to be carried in. An open / close valve is provided between the load lock chamber and the vacuum chamber.
[0006]
The apparatus shown in FIG. 3 forms a thin film by vapor deposition according to the following procedure. After introducing the substrate into the load lock chamber, evacuation in the vacuum chamber, initialization of the vapor deposition material (melting and degassing step of the vapor deposition material), heating of the vapor deposition source, and then the substrate is loaded into the load lock chamber. Then, the substrate is transferred to the substrate holder 12 in the vacuum chamber, vapor deposition is started, an organic thin film having a predetermined thickness is formed on the substrate, and after the vapor deposition is completed, the thin film formed substrate is led out from the vacuum chamber.
[0007]
Even if the evaporation source is heated in the above-described deposition thin film forming procedure, if the evaporation shutter 23 is kept closed, the vapor of the organic material does not reach the substrate, and the evaporation shutter is started at the start of evaporation on the substrate. 23 is driven to an open state. Further, at the time of starting the vapor deposition, the deposition preventing plate 19 is driven to the closed state to prevent the vapor deposition substance from adhering to the viewing window. Note that after the start of vapor deposition, the vapor of the organic material adheres to the film thickness monitor 22 as well as the substrate 18. Thereby, the organic thin film formation speed and film thickness to a board | substrate can be measured indirectly.
[0008]
[Problems to be solved by the invention]
Incidentally, the conventional organic thin film vapor deposition apparatus and vapor deposition method shown in FIG. 3 have the following problems.
[0009]
In the conventional vapor deposition apparatus, when performing initialization (deposition and melting process of vapor deposition material) before the start of vapor deposition, the surface of the vapor deposition material is not visible, and there is a problem that insufficient melting of the material occurs in the initialization process. . In addition, in order to solve this problem, there is a method in which the material is completely melted and degassed, and initialization is performed over a time longer than necessary, but in this case, the material consumption is remarkably increased, There was a cost problem.
[0010]
In addition, a viewing window for observing the inside of the vacuum chamber is provided at a position facing the deposition material surface, and a rotating shutter is provided in front of the viewing window to prevent the deposition material from adhering to the viewing window, and steam is rotated at this position. An apparatus for trapping with a shutter is disclosed in Japanese Patent Laid-Open No. 8-3742. However, in the case of this apparatus, although the observation window is provided at a position facing the vapor deposition material surface, many members that interfere with the observation of the vapor deposition material surface are interposed between the observation window and the vapor deposition material surface. However, the surface of the vapor deposition material is not in a sufficiently visible state, and there is a rotating shutter and the driving unit, and the structure thereof is extremely complicated, so that a simpler configuration as an apparatus is desired.
[0011]
Further, in the conventional apparatus shown in FIG. 3, the evaporation film or the like attached in the vacuum chamber in the initialization and film formation process is caused by the operation of the evaporation shutter 23 and the deposition preventing plate 19 that are driven as the evaporation starts and ends. The dust generated from the peeling film and the drive shaft is mixed into the evaporation source or adheres to the film forming surface, which causes a deterioration or poor quality of the film.
[0012]
In particular, in the case of an organic thin film element such as an organic EL display, since the organic film thickness is as very thin as about 100 nm, there has been a problem that the film quality is likely to deteriorate or fail. The organic thin film element is required to have a lower voltage and lower power consumption than before, and in this case, it is necessary to further reduce the film thickness. Therefore, in order to reduce defects in the film forming process, the dust in the vacuum chamber is required. It is necessary to suppress the occurrence of the above and improve the cleanliness.
[0013]
The present invention has been made in view of the above points, and an object of the present invention is to enable sufficient observation of the surface of a vapor deposition material with a simple structure and to generate a release film and dust in a vacuum chamber. by suppressing is to provide a vapor Chakuhoho organic thin film which aimed at defect reduction of the deposited film.
[0014]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention has a load lock chamber for stocking a substrate for forming an organic thin film, and means for introducing an inert gas, and is conveyed from the load lock chamber via a conveying means. A vacuum chamber for introducing a substrate and performing an organic thin film deposition process, a substrate holder provided in the vacuum chamber, a vapor deposition material evaporation source provided facing the thin film formation surface of the substrate, and a wall of the vacuum chamber The organic thin film is formed on the substrate without using an evaporation shutter by using an organic thin film vapor deposition device equipped with a viewing window for monitoring the vapor deposition material provided on the surface and an adhesion prevention plate that prevents the deposition material from adhering to the viewing window. In the organic thin film vapor deposition method, after the substrate is introduced into the load lock chamber, the vacuum chamber is evacuated, the vapor deposition material is initialized, and the vapor deposition source is heated. Melted After confirming the door, introducing an inert gas into the vacuum chamber, and thereafter, after transporting a predetermined position in the vacuum chamber a substrate from the load lock chamber, deposition by evacuating the inert gas the introduction Then, as soon as an organic thin film having a predetermined thickness is formed on the substrate, the inert gas is introduced again to complete the evaporation, and the thin film formed substrate is led out from the vacuum chamber ( (Invention of Claim 1)
[00 15 ]
More inventions of the claim 1, wherein to allow sufficient observation of the deposition material surface, and it is possible to suppress the occurrence of flaking film or dust in a vacuum chamber, and further, to the vacuum chamber By introducing the inert gas before vapor deposition, it is possible to prevent the evaporating substance from reaching the substrate in the load lock chamber. By the above, the organic thin film vapor deposition method which aimed at the defect reduction of a vapor deposition film as a whole can be provided.
[00 16 ]
As the pressure of the inert gas, the invention of claim 2 is preferable. That is, in the vapor deposition method according to claim 1 , the pressure of the inert gas atmosphere in the vacuum chamber before the vapor deposition is started is 0.5 Pa to 10 Pa. Details will be described later.
[00 17 ]
In the vapor deposition method according to claim 1 or 2 , the film thickness of the organic thin film is controlled by the temperature of the vapor deposition source and the vapor deposition time (invention of claim 3 ). Although the film thickness monitor 22 shown in FIG. 3 may be used as in the prior art, the apparatus configuration is simplified by applying the invention of claim 3 .
[00 18 ]
DETAILED DESCRIPTION OF THE INVENTION
Based on FIG. 1 and FIG. 2, an embodiment of the present invention will be described below. Figure 1 is a schematic diagram of a vapor deposition apparatus of the organic thin film that involved in the present invention. In FIG. 1, members having the same functions as those in the apparatus shown in FIG.
[00 19 ]
The difference between the apparatus of FIG. 1 and the apparatus of FIG. 3 is that, in FIG. 1, first, a viewing window 17 is provided on the wall of the vacuum chamber 11 at a position facing the back side of the thin film forming surface of the substrate 18. Further, an adhesion preventing plate 19 made of a transparent material is provided between the observation window 17 and the substrate 18. Further, the vacuum chamber 11 includes an inert gas introduction unit including an inert gas cylinder 14, a mass flow controller 21, a valve 20, and the like.
[00 20 ]
Further, the substrate holder 12 shown in FIG. 1 includes a skirt portion along the side wall of the vacuum chamber and a ceiling plate portion parallel to the ceiling wall of the vacuum chamber in order to prevent the deposition material from adhering to the inner wall of the vacuum chamber 11. Yes. Furthermore, as described above, the apparatus shown in FIG. 1 does not include the evaporating shutter 23 and its driving mechanism, the driving mechanism for the deposition preventing plate 19, the film thickness monitor 22 and the like in FIG. 3 is different from FIG. 1 can be used, for example, a soda lime glass plate, which can be attached to and detached from the substrate holder 12 via the deposition plate holding member 13. Mounted as possible.
[00 21 ]
The procedure for forming a vapor deposition film using the apparatus of FIG. 1 will be described below. FIG. 2 is a flowchart showing a procedure for forming a deposited film. A substrate is introduced into a load lock chamber (not shown), and an organic material is placed in the evaporation source 15 attached to the bottom plate of the vacuum chamber 11 to perform vacuum evacuation (S _{1 in} FIG. 2). After reducing the internal pressure of the vacuum chamber to 1 × 10 ⁻⁴ Pa, the vapor deposition source 15 is heated in a state where the substrate 18 does not exist in the vacuum chamber 11, and the vapor deposition material is initialized (S _{2 in} FIG. ₂ ).
[00 22 ]
At this time, since the vapor deposition material surface 16 can be seen from the viewing window 17, melting of the material can be visually observed. Therefore, the initialization process can be ended immediately after melting, and the consumption of material can be reduced. Further, since there is the soda lime glass deposition plate 19, adhesion of the film to the viewing window 17 can be prevented. Further, since the deposition preventing plate 19 is arranged on the upper portion of the deposition preventing plate holding member 13, it can be easily attached and detached, and a lid plate (not shown) provided on the upper portion of the vacuum chamber 11 is opened to remove the deposition preventing plate 19. Maintenance to remove and remove the attached film can be easily performed.
[00 23 ]
Next, after completion of the initialization (S _{2 in} FIG. 2), the evaporation source 15 is heated (S _{3 in} FIG. 2) to obtain a predetermined temperature or a predetermined film forming speed. The evaporation source 15 is controlled so that After confirming that the evaporation source 15 has reached a predetermined temperature or that the vapor deposition material has reached a predetermined molten state, an inert gas is introduced into the vacuum chamber (S _{4 in} FIG. 2).
[00 24 ]
By introducing an inert gas and increasing the pressure in the vacuum chamber 11, it is possible to prevent the substance evaporated from the evaporation source 15 from reaching the substrate surface standing by in the load lock chamber. Experiments have confirmed that the pressure of the inert gas atmosphere required for this is preferably in the range of 0.5 Pa to 10 Pa, more preferably 1 Pa to 5 Pa. When the pressure is too high, it takes time for evacuation, and the film quality at the initial stage of film formation is deteriorated. If the pressure is too low, the evaporated substance will reach the substrate surface from the evaporation source 15. In this embodiment, 1 Pa of Ar gas is introduced, but the type of gas is not limited to this, and nitrogen gas may be used.
[00 25 ]
In this state, the substrate 18 is introduced from the load lock chamber onto the substrate holder in the vacuum chamber 11 (S _{5 in} FIG. 2). A board | substrate is conveyed by the transfer rod, for example from the side wall part of a vacuum chamber. At that time, the inert gas is also introduced into the load lock chamber in advance to prevent pressure fluctuation when the valve is opened and closed between the vacuum chamber and the load lock chamber. As a result, dust generation due to airflow can also be suppressed.
[00 26 ]
After the substrate 18 is introduced into the position shown in FIG. 1 (S _{5 in} FIG. 2), the introduced inert gas is evacuated (in FIG. 2, the illustration of this step is omitted) to start vapor deposition (FIG. 2). S ₆ ), and the film is formed on the substrate 18. Thereafter, a desired time, or as soon as the film thickness, the inert gas again (S ₇ of FIG. 2) by (in FIG. 2, the illustration of the process is also omitted) that, to terminate the deposition.
[00 27 ]
Thereafter, the substrate 18 is taken out (S _{8 in} FIG. 2), the vacuum chamber 11 is evacuated (S _{9 in} FIG. 2), the evaporation source 11 is cooled (S _{10 in} FIG. 2), and the process ends.
[00 28 ]
As described above, by the method of the inventive deposition lever, inside the vacuum chamber 11, because there is no place for mechanically driven, separation of the film attached by the drive, dust generation from a driving shaft There is no. Therefore, even with an element using an extremely thin film such as an organic EL display, the occurrence of defects can be prevented. Further, since the vapor deposition material surface 16 can be visually observed in the initialization of the evaporation material, the state of the material can be confirmed quickly, the efficiency of the initialization process can be improved, and the material consumption can be reduced. In addition, no film adheres to the viewing window 17, and it is possible to perform visual observation continuously for a long period of time and to improve maintainability by simply cleaning or replacing the deposition preventing plate 19.
[00 29 ]
In the above description, a case where only one thin film is formed using one vacuum chamber has been described, but the same vapor deposition can be applied even when applied to a cluster type or inline type apparatus having a plurality of vacuum chambers. The method is applicable.
[0030]
【The invention's effect】
As described above, according to the present invention, the load lock chamber for stocking the substrate for forming the organic thin film and the introduction means for the inert gas are introduced, and the substrate conveyed from the load lock chamber via the conveyance means is introduced. A vacuum chamber for performing an organic thin film deposition process, a substrate holder provided in the vacuum chamber, an evaporation source of a vapor deposition material provided facing the thin film formation surface of the substrate, and a wall of the vacuum chamber. Organic thin film that forms an organic thin film on a substrate without using an evaporation shutter by using an organic thin film vapor deposition device comprising a viewing window for observing the deposited material and an adhesion preventing plate for preventing deposition of vapor deposition material on the viewing window In the vapor deposition method, after the substrate is introduced into the load lock chamber, the vacuum chamber is evacuated, the vapor deposition material is initialized, and the vapor deposition source is heated, so that the vapor deposition source is at a predetermined temperature or the vapor deposition material is in a predetermined molten state. Make sure After, introducing an inert gas into the vacuum chamber, thereafter, the after transporting a predetermined position in the vacuum chamber a substrate from the load lock chamber starts deposited by evacuating the inert gas the introduction Then, as soon as an organic thin film having a predetermined thickness is formed on the substrate, the deposition is terminated by introducing an inert gas again, and the thin film formed substrate is led out from the vacuum chamber.
Provided is a method for depositing organic thin films that enables a sufficient observation of the surface of the vapor deposition material with a simple structure and reduces the defects of the vapor deposition film by suppressing the generation of peeling films and dust in the vacuum chamber. be able to.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an organic thin film deposition apparatus according to an embodiment of the present invention. FIG. 2 is a flowchart showing an organic thin film deposition procedure according to an embodiment of the present invention. Schematic configuration diagram showing an example of the device [Explanation of symbols]
11: Vacuum chamber, 12: Substrate holder, 13: Protection plate holding member, 14: Inert gas cylinder, 15: Evaporation source, 16: Surface of vapor deposition material, 17: Viewing window, 18: Substrate, 19: Protection plate, 20: Valve, 21: Mass flow controller.

Claims (3)

A vacuum having a load lock chamber for stocking a substrate for forming an organic thin film and an inert gas introduction means, and introducing the substrate conveyed from the load lock chamber via the conveyance means to perform an organic thin film deposition process. A tank, a substrate holder provided in the vacuum chamber, a vapor deposition material evaporation source provided facing the thin film forming surface of the substrate, and a viewing window for vapor deposition material observation provided on the wall of the vacuum chamber; In the organic thin film vapor deposition method for forming an organic thin film on a substrate without using an evaporation shutter by an organic thin film vapor deposition device provided with an adhesion preventing plate for preventing the deposition of a vapor deposition substance on the viewing window, the load lock chamber includes After introducing the substrate, vacuum evacuation in the vacuum chamber, initialization of the vapor deposition material, heating of the vapor deposition source, and after confirming that the vapor deposition source is at a predetermined temperature or a predetermined molten state, the vacuum chamber Inert gas inside Type, thereafter, after transporting a predetermined position in the vacuum chamber a substrate from the load lock chamber, the inert gas the introducing starts deposited by vacuum evacuation, then the organic thin film having a predetermined thickness on the substrate As soon as is formed, an inert gas is introduced again to complete the vapor deposition, and the thin film-formed substrate is led out from the vacuum chamber. The vapor deposition method of Claim 1 WHEREIN: The pressure of the inert gas atmosphere in the vacuum chamber before the said vapor deposition start is 0.5Pa-10Pa, The vapor deposition method of the organic thin film characterized by the above-mentioned. 3. The vapor deposition method according to claim 1, wherein the thickness of the organic thin film is controlled by the temperature of the vapor deposition source and the vapor deposition time.

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