JP2004079349A - Thin film forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin film forming device in which a mask for coating picture elements dividedly is attached to a base board using a permanent magnet, capable of precluding a dislocation when fixing the mask. <P>SOLUTION: The thin film forming device includes the base board 3 held by a holder 2, and the mask 5 attached to the surface of the base board 3 is attracted to the permanent magnet 4 installed on the rear surface of the holder 2 and fixed to the base board 3. The permanent magnet 4 is moved in the directions approaching and separating from the holder 2 by a sliding mechanism 7. When setting the mask 5, the permanent magnet 4 is moved to a position apart from the mask 5, to align without being influenced by the magnetic force of the permanent magnet 4. When fixing the mask 5, the permanent magnet 4 is moved in an approaching direction toward the mask 5 gradually, to slowly fix the mask 5. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a thin film forming apparatus for forming a thin film by placing a mask for pattern formation on a substrate. Specifically, the mask is to be attracted and held by the permanent magnet from the back side of the substrate, and the permanent magnet is gradually moved toward and away from the mask so that the magnetic force of the permanent magnet gradually decreases. The mask is fixed so as to reach the mask.
[0002]
[Prior art]
An organic EL (electroluminescence) panel is known as an element or a substrate manufactured using a thin film forming apparatus such as a vacuum evaporation apparatus. The organic EL element constituting this organic EL panel is a light emitting material using an organic substance for a light emitting layer. This organic EL element is used as a light-emitting material for various display devices such as a flat panel display used in a computer or a television receiver, a display of a mobile phone, and a display of a mobile terminal called PDA (Personal Digital Assistants). Also, it is used as a light emitting element such as a light emitting diode.
[0003]
FIG. 8 is an explanatory view showing an example of the structure of the organic EL element. The organic EL element 101 is obtained by sequentially laminating an ITO (Indium-Tin Oxide) transparent electrode 103, an organic film 104, and a back electrode 105 serving as a cathode on a transparent substrate 102 such as glass. The organic film 104 is formed by sequentially stacking a hole injection layer 104a, a hole transport layer 104b, a light emitting layer 104c, an electron transport layer 104d, and an electron injection layer 104e from the side of the ITO transparent electrode 103.
[0004]
When a voltage is applied between the ITO transparent electrode 103 and the back electrode 105, a positive charge (hole) is injected from the ITO transparent electrode 103, and a negative charge (electron) is injected from the back electrode 105. Moving. Then, electrons and holes are recombined with a certain probability in the light emitting layer 104c, and light having a predetermined wavelength is generated at the time of the recombination.
[0005]
Note that the organic film 104 has a structure in which the hole injection layer 104a and the hole transport layer 104b are formed in one layer, a structure in which the electron transport layer 104d and the electron injection layer 104e are formed in one layer, and a structure in which the light emitting layer 104c is formed. For example, the electron transport layer 104d and the electron injection layer 104e are formed as a single layer.
[0006]
FIG. 9 is a plan view showing an outline of an organic EL color display configured using such an organic EL element, and FIG. 10 is a perspective view of a main part of the organic EL color display. In the organic color display 106, an ITO transparent electrode 103 is formed on a transparent substrate 102 in a stripe shape. Further, the organic film 104 is formed in a stripe shape so as to be orthogonal to the ITO transparent electrode 103, and the back electrode 105 is formed on the organic film 104. The ITO transparent electrode 103, the organic film 104, and the back electrode 105 are arranged in a matrix. Deploy. As a result, the organic film 104 at the intersection of the ITO transparent electrode 103 to which the voltage is applied and the back electrode 105 emits light.
[0007]
Then, as the organic film 104, an organic film 104R that emits red (R) light, an organic film 104G that emits green light (G), and an organic film 104B that emits blue light (B) are arranged in order to form a pixel by RGB. Thus, color display becomes possible.
[0008]
By the way, the formation of the organic film using a low-molecular-weight organic substance uses a vacuum evaporation method. The vacuum evaporation method is a method in which a raw material is heated and evaporated in a high vacuum, and the raw material is adsorbed on a substrate facing an evaporation source to form a thin film.
[0009]
FIG. 11 is an explanatory diagram showing a basic configuration of a vacuum evaporation apparatus that performs such a vacuum evaporation method. The chamber 107 is connected to an exhaust pump (not shown), and the interior of the chamber 107 can be evacuated to a high vacuum. Here, the degree of vacuum in the chamber 107 in the vacuum evaporation method is 10 ^-3 -10 ^-4 It is about Pa (Pascal).
[0010]
The evaporation source 108 is a heating source for evaporating a raw material, here, an organic raw material, and includes resistance heating, electron beam heating, infrared heating, high-frequency induction heating, and the like. Resistance heating is generally used for an organic film. As the resistance heating, the powdery organic raw material 110 is placed in an open container 109 called a boat, and the organic raw material 110 is indirectly heated by indirect heating of the organic raw material 110 due to the resistance heating of the open container 109 by energizing the open container 109. It evaporates or sublimates.
[0011]
A substrate 111 on which an organic film is to be formed (corresponding to the transparent substrate 102 on which the ITO transparent electrode 103 shown in FIG. 8 and the like is formed) is attached to a substrate holder 112 and arranged to face the evaporation source 108. The substrate holder 112 holds the substrate 111 so that the surface on which the organic film is formed faces vertically downward.
[0012]
When the organic material 110 is vaporized or sublimated by the evaporation source 108 under a high vacuum in the chamber 107, the organic raw material reaches the substrate 111 in a beam form. At this time, the film distribution is made uniform by rotating the substrate holder 112.
[0013]
When the color display shown in FIG. 10 or the like is formed, an organic film is formed using a mask for pattern formation, in this case, a mask for pixel painting. FIG. 12 is an explanatory view of a conventional mask fixing device. The mask 114 has a stripe-shaped pattern 115. In order to attach the mask 114 to the substrate 111, a clamp 116 for holding the mask 114 on the substrate holder 112 is provided in the configuration shown in FIG.
[0014]
In the structure shown in FIG. 12B, a magnet is used to make the mask 114 adhere to the substrate 111. That is, the mask 114 is made of a magnetic material, and a mechanism (not shown) for holding the substrate 111 is provided with a magnetized member 117 made of a permanent magnet or an electromagnet. Then, the substrate 111 is placed on the magnetized member 117, and the mask 114 is placed on the substrate 111, so that the mask 114 comes into close contact with the substrate 111 by the magnetic force of the magnetized member 117.
[0015]
Then, in order to form R, G, and B organic films, the mask 114 is first attached to a predetermined position to form the organic film 104R shown in FIG. 12, and then the attachment position of the mask 114 is shifted by ３ pitch. Then, the organic film 104B is formed by shifting the mounting position of the mask 114 by 1/3 pitch.
[0016]
[Problems to be solved by the invention]
However, when the mask is held by using a clamp, there is a problem that the position of the mask is displaced by the rotation operation of the substrate holder and patterning failure occurs. Further, it is necessary to increase the width of the organic film as shown in FIG. 10 and the like in consideration of the displacement of the mask, so that there is a problem that it is difficult to achieve high definition.
[0017]
Among the methods of fixing the mask using magnets, the configuration using electromagnets requires a power supply for driving the electromagnets, a controller, a mechanism for cooling the electromagnets, and the like. There was a problem that becomes high. Further, when a mechanism for rotating the substrate holder is provided, there is a problem that the apparatus configuration is further complicated.
[0018]
In the configuration using a permanent magnet, the mask is attached to a predetermined position, so that the mask is pulled from the substrate with a stronger force than the magnetic force of the permanent magnet because the permanent magnet attracts the mask even during alignment of the mask and the substrate. Alignment must be performed while holding the device at a fixed distance, and there is a problem that the size of a complicated mechanism and apparatus is increased and a cost is increased.
[0019]
Furthermore, when the substrate and the mask are held in close contact with each other after the alignment, the mask is suddenly attracted by the magnetic force of the permanent magnet at the moment when the mask is released from being held at a certain distance from the substrate. This causes a problem that patterning failure occurs, and as a result, it is difficult to achieve high definition.
[0020]
SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a thin film forming apparatus capable of preventing mask displacement with a simple configuration.
[0021]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a thin film forming apparatus according to the present invention includes a holding means for holding a substrate in a thin film forming apparatus in which a mask for pattern formation is mounted on a substrate, and a substrate of the holding means. A permanent magnet provided on the back surface side of the holding surface and adsorbing the mask on the substrate held by the holding means; and a moving means for moving the permanent magnet in a direction approaching and moving away from the mask. It is.
[0022]
In the thin film forming apparatus according to the present invention, when the mask is set on the substrate, the moving means holds the permanent magnet at a position away from the mask. When the mask is set at a predetermined position, the moving means gradually moves the permanent magnet in a direction approaching the mask. Then, the mask is attracted by the magnetic force of the permanent magnet, and the mask is fixed on the substrate.
[0023]
In this way, by holding the permanent magnet at a position away from the mask on the substrate and gradually bringing the permanent magnet closer to the mask, the magnetic force of the permanent magnet gradually reaches the mask, and the mask Position shift is prevented.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a thin film forming apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a main configuration of the thin film forming apparatus according to the first embodiment. The thin film forming apparatus 1 of the present embodiment has a mask fixing device 6 for fixing a mask 5 with a permanent magnet 4 to a substrate 3 held on the front side of a substrate holder 2 as a holding means. The mask fixing device 6 has a slide mechanism 7 as a moving unit that slides the permanent magnet 4 provided on the back side of the substrate holder 2 in a direction approaching and separating from the substrate holder 2.
[0025]
When the mask 5 is set on the substrate 3, the slide mechanism 7 separates the permanent magnet 4 from the substrate holder 2 so that the magnetic force of the permanent magnet 4 does not reach the mask 5, so that accurate positioning of the mask 5 can be performed. It is like that. When the mask 5 is fixed, the permanent magnet 4 is gradually moved closer to the substrate holder 2 by the slide mechanism 7, thereby preventing the mask 5 from being displaced.
[0026]
Here, the substrate 3 is a substrate in which an ITO transparent electrode is formed on the transparent glass substrate 102 described with reference to FIG. 8 and the like, or a TFT (Thin Film Transistor) substrate (not shown).
[0027]
The substrate holder 2 has a plurality of positioning pins 2a for determining the position of the substrate 3 on the front side. The positioning pins 2a include two pins that contact one side of the rectangular substrate 3 and one pin that contacts another side orthogonal to the one side.
[0028]
In the present embodiment, the mask 5 is used when the pixels are separately applied in the manufacturing process of the organic EL panel, and is provided with slits 5a arranged in a thin plate. Here, the mask 5 is formed entirely of a thin plate of a magnetic material, or a structure in which a member of a magnetic material is attached to a part of a thin plate of a non-magnetic material, for example, an edge.
[0029]
For example, when the entire mask 5 is made of a magnetic material, the permanent magnet 4 has a size equivalent to that of the mask 5 and can apply a magnetic force to the entire mask 5. The permanent magnet 4 is attached to the support base 8 and slides by the slide mechanism 7.
[0030]
The slide mechanism 7 is provided on the back surface side of the substrate holder 2 and, for example, is fed by a combination of a feed screw 7a driven by a motor (not shown) and a nut 8a provided on a support 8 to which the permanent magnet 4 is attached. The position of the permanent magnet 4 is made variable by the rotation of the screw 7a.
[0031]
Thus, the permanent magnet 4 attached to the support 8 moves in a direction to approach and separate from the mask 5 attached to the substrate 3 held by the substrate holder 2. The slide mechanism 7 can control the moving speed of the permanent magnet 4 by controlling the rotation speed of a motor (not shown).
[0032]
Although the configuration of the slide mechanism 7 is not limited to this, it overcomes the magnetic force of the permanent magnet 4 so that any speed control can be performed regardless of the distance to the mask 5 which is a magnetic material. A mechanism that can hold the position of the permanent magnet 4 is required.
[0033]
FIG. 2 is an overall configuration diagram of the thin film forming apparatus 1 of the present embodiment, and the configuration of other parts of the thin film forming apparatus 1 will be described below. The thin film forming apparatus 1 according to the present embodiment uses an organic vapor deposition method (organic vapor deposition) in which an organic material in a vapor phase is transported into a low vacuum chamber 11 using a carrier gas to form an organic film on the substrate 3. It employs a method called vapor phase deposition.
[0034]
The thin film forming apparatus 1 includes a chamber 11, a vaporization sublimation chamber 12 for vaporizing or sublimating an organic raw material, and a raw material gas transport pipe 13 connecting the vaporization sublimation chamber 12 and the chamber 11. The substrate holder 2 provided with the mask fixing device 6 as shown in FIG. This substrate holder 3 has a mechanism for circulating, for example, cooling water supplied from a cooling pipe 14 as a cooling means, and cools the held substrate 3 from the back surface side (the surface opposite to the organic film forming surface). .
[0035]
FIG. 3 is a perspective view of the mask fixing device 6 incorporated in the thin film forming apparatus 1 shown in FIG. 2, and FIG. 4 is a side view of the mask fixing device 6. In the thin film forming apparatus 1 shown in FIG. 1, a shaft 2b through which a cooling pipe 14 passes is provided on the back side of the substrate holder 2. The shaft 2b serves as a rotation center when a mechanism for rotating the substrate holder 2 is provided, as described later. Therefore, the permanent magnet 4 is provided with a hole 4a through which the shaft 2b passes.
[0036]
Then, the permanent magnet 4 is separated from the substrate holder 2 by a predetermined distance from a position in close contact with the back surface of the substrate holder 2 as shown by a solid line in FIGS. The slide mechanism 7 slides in a direction to approach and separate from the substrate holder 2 while maintaining the parallel relationship with the back surface of the substrate holder 2 to the position where the substrate holder 2 is moved.
[0037]
Returning to FIG. 2, the chamber 11 is provided with a pressure gauge 15 and an exhaust pipe 16. A vacuum pump (not shown) constituting an exhaust means is connected to the exhaust pipe 16, and the output of the pressure gauge 15 is fed back to control the pressure in the chamber 11 to maintain a predetermined low vacuum.
[0038]
Here, although not shown, a heater and a thermometer may be provided in the chamber 11 so that the temperature in the chamber 11 is controlled so as to maintain a temperature at which the organic raw material before being adsorbed on the substrate 3 does not solidify. . In order to allow the substrate 3 to be freely inserted into and taken out of the chamber 11, for example, the chamber 11 has a split structure having an open / close structure, and when closed, airtightness is maintained.
[0039]
The vaporization sublimation chamber 12 constitutes vaporization sublimation means and vaporizes or sublimates an organic raw material by, for example, a resistance heating method, and includes a boat-shaped raw material container 17 in a container such as a chamber that can be isolated from outside air. . Further, an unillustrated energizing mechanism for energizing the raw material container 17 is provided.
[0040]
The raw material container 17 is made of a material such as Ta (tantalum) which has a high melting point and does not react with the organic raw material. When power is supplied to the raw material container 17, the raw material container 17 becomes a resistor and generates heat. When the solid phase (powder) organic raw material 18 is put into the raw material container 17 and energized, the raw material container 17 generates heat, whereby the organic raw material 18 is indirectly heated and vaporized or sublimated. Thereby, H ₂ O or O ₂ The inside of the vaporization sublimation chamber 12, which is completely isolated from substances that alter the quality of the organic raw material, is filled with the gas of the organic raw material.
[0041]
A pressure gauge 19 is provided in the vaporization sublimation chamber 12. When the amount of the organic raw material 18 decreases in the vaporization sublimation chamber 12, the pressure in the vaporization sublimation chamber 12 decreases. For this reason, a pressure gauge 19 is provided in the vaporization sublimation chamber 12 to measure the pressure in the vaporization sublimation chamber 12, and when a decrease in the pressure is detected, an instruction to replenish the raw material is issued. Make replenishment possible.
[0042]
Here, in the present embodiment, two independent vaporization sublimation chambers 12 are provided. A supply pipe 20 is connected to each of the vaporization sublimation chambers 12. Each supply pipe 20 is provided with a flow rate controller 21. Each supply pipe 20 is connected to a tank 22. Since the tank 22 is used as a carrier gas, N 2 inert to various organic raw materials is used. ₂ And a gas such as Ar (argon). Then, the flow rate of the carrier gas sent to the vaporization sublimation chamber 12 is independently controlled by the flow rate controller 21. The above-described vaporization sublimation chamber 12 and a mechanism for supplying a carrier gas to the vaporization sublimation chamber 12 constitute a carrier gas introduction unit.
[0043]
A source gas transport pipe 13 constituting source gas transport means is connected to each vaporization sublimation chamber 12. The source gas transport pipe 13 is also connected to the chamber 11, and an injector 23 constituting discharge means is provided at an end of the source gas transport pipe 13 inside the chamber 11 at a position facing the substrate 3.
[0044]
A heater 24 is provided in the vaporization sublimation chamber 12 and the source gas transport pipe 13 on the downstream side of the flow controller 21 of each supply pipe 20. Further, temperature sensors 25a and 25b are provided in the vaporization sublimation chamber 12 and the raw material gas transport pipe 13. Thus, the heater 24 is controlled so that the temperature of the carrier gas or the source gas is maintained at a temperature at which the organic source does not solidify.
[0045]
Although not shown, a thermocouple for measuring the temperature of the raw material container 17 is provided in the vaporization sublimation chamber 12 in order to control the heating temperature of the organic raw material 18. Further, an ammeter for measuring a current value when energizing the raw material container 17 is provided. As a result, the temperature of the raw material container 17 and the value of the current supplied to the raw material container 17 are monitored, and control is performed so that the temperature at which the organic raw material 18 evaporates or sublimes is maintained. In addition, by measuring the pressure and temperature of the vaporization sublimation chamber 12, the organic raw material 18 is controlled to keep the vaporization or sublimation amount constant.
[0046]
FIG. 5 is an explanatory view showing a process of attaching the substrate 3 and the mask 5. Next, an operation of attaching the substrate 3 and the mask 5 to the substrate holder 2 will be described. It is known that the magnetic force acting between two magnetic poles is inversely proportional to the square of the distance between the two magnetic poles, and is proportional to the product of the strengths of the two magnetic poles. That is, F (N) is the force acting between the magnetic poles, m1 and m2 (wb) are the strengths of the magnetic poles, m (wb) is the magnetic force of the permanent magnet 4, r (m) is the distance between the magnetic poles, here When the distance between the permanent magnet 4 and the mask 5 is set, the following equation (1) is established.
F = 1 / 4πμ × (m1 · m2) / R ² = 6.33 × 10 ⁴ × m / r ² ・ ・ (1)
[0047]
Equation (1) shows that as the distance between the permanent magnet 4 and the mask 5 increases, the magnetic force exerted on the mask 5 by the permanent magnet 4 rapidly decreases. Therefore, by making the distance between the permanent magnet 4 and the mask 5, that is, the distance between the permanent magnet 4 and the substrate holder 2 arbitrarily variable at a certain speed, the alignment of the mask 5 can be performed without being affected by the magnetic force. At the same time, the mask 5 can be gradually fixed without suddenly exerting the influence of the magnetic force.
[0048]
First, before attaching the substrate 3 and the mask 5, the slide mechanism 7 moves the permanent magnet 4 to a position away from the substrate holder 2 as shown in FIG. The position of the permanent magnet 4 is a distance at which the magnetic force of the permanent magnet 4 does not affect the alignment of the mask 5 on the substrate 3 set on the substrate holder 2.
[0049]
As described above, the substrate 3 is first set on the substrate holder 2 with the permanent magnet 4 separated from the substrate holder 2. The substrate 3 is positioned with respect to the substrate holder 2 by setting the side of the substrate 3 by abutting the sides against the positioning pins 2a.
[0050]
Next, as shown in FIG. 5B, alignment is performed while holding the mask 5 on the substrate 3 set on the substrate holder 2. For example, while monitoring the position of the mask 5 with the CCD camera 26, the mask 5 is rotated on a plane horizontal to the surface of the substrate 3 and slid in the X and Y directions to position the mask 5 with respect to the substrate 3. Do.
[0051]
Then, as shown in FIG. 5C, the positioned mask 5 is set on the substrate 3. At this time, since the permanent magnet 4 remains retracted to a position that does not affect the alignment of the mask 5, there is no need to perform positioning against the magnetic force of the permanent magnet 4 during the alignment shown in FIG. , Accurate positioning can be performed. Also, when the mask 5 is set on the substrate 3 as shown in FIG. 5 (c), the mask 5 is not pulled in the direction of the substrate 3 by the magnetic force of the permanent magnet 4, so that the posture determined by the alignment is maintained. It can be set on the substrate 3 as it is.
[0052]
Next, as shown in FIG. 5D, the permanent magnet 4 is moved by the slide mechanism 7 in a direction approaching the substrate holder 2. The moving speed v at this time may be constant. When the distance between the substrate holder 2 and the permanent magnet is r, vｒr ² May be changed according to the following relationship. That is, it is preferable to perform control such that the moving speed is reduced as the distance between the substrate holder 2 and the permanent magnet 4 is reduced.
[0053]
In this way, by controlling the speed so that the moving speed of the permanent magnet 4 decreases as the distance from the substrate holder 2 decreases, it is possible to fix the mask 5 to the substrate 3 while slowly bringing the mask 5 into close contact with the substrate 3. it can. Thereby, it is possible to prevent the displacement of the mask 5 that occurs when the substrate 3 and the mask 5 are fixed. Further, when the distance between the permanent magnet 4 and the mask 5 is large, the influence of the magnetic force is weak. Therefore, by increasing the moving speed, it is possible to prevent the time required for fixing the mask 5 from increasing. Then, as shown in FIG. 5E, when the permanent magnet 4 is moved to a position where it is brought into close contact with the back surface of the substrate holder 2, the movement of the permanent magnet 4 by the slide mechanism 7 is stopped. As a result, the mask 5 is attracted to the permanent magnet 4 and is held on the front surface side of the substrate 3.
[0054]
Next, an organic film forming operation in the thin film forming apparatus 1 will be described with reference to FIG. The organic film forming step in the organic vapor deposition method includes a vaporization sublimation step of vaporizing or sublimating an organic raw material, a carrier gas introducing step of introducing a carrier gas, and a raw gas transport of transporting the raw material gas onto the substrate 3 using the carrier gas. It comprises a process, a process of depositing an organic film on the substrate 3 and a process of exhausting.
[0055]
The vaporization sublimation step is performed in the vaporization sublimation chamber 12. In the vaporization sublimation step, a current is supplied to the raw material container 17 containing the organic raw material 18, and the organic raw material 18 is indirectly heated and vaporized or sublimated by resistance heating of the raw material container 17 to generate a raw material gas.
[0056]
Thereby, H ₂ O or O ₂ The inside of the vaporization sublimation chamber 4 that is completely isolated from substances that alter the organic raw material such as the above is filled with the raw material gas. In the vaporization sublimation step, the temperature of the raw material container 17 and the value of the current supplied to the raw material container 17 are monitored, and the organic raw material 18 is controlled to keep the amount of vaporization or sublimation constant. Further, the pressure in the vaporization sublimation chamber 12 is monitored by the pressure gauge 15, and when a decrease in pressure is detected, control is performed so as to issue an instruction to replenish the raw material.
[0057]
The carrier gas introduction step is performed in the vaporization sublimation chamber 12. In this carrier gas introduction step, introduction of a carrier gas for dilution and transport of the source gas is performed. That is, a gas inert to various organic raw materials is sent from the tank 22 to the vaporization sublimation chamber 12 as a carrier gas. A flow controller 21 is provided in each of supply pipes 20 connecting the tank 22 and each of the vaporization sublimation chambers 12, and a carrier gas whose flow rate is controlled is sent into the vaporization sublimation chamber 12. Then, the carrier gas and the source gas sent into the vaporization sublimation chamber 12 are mixed, and the source gas is sent to the source gas transport pipe 13 using the carrier gas.
[0058]
Here, in the carrier gas introduction step, the temperature of the carrier gas is controlled by heating the supply pipe 20 with the heater 24 in order to avoid the solidification of the organic material due to the temperature decrease of the source gas in the vaporization sublimation chamber 12. Further, the flow controller 21 controls the supply amount of the carrier gas to be constant. As described above, by keeping the amount of the carrier gas supplied to the vaporization sublimation chamber 12 constant, and keeping the amount of vaporizing or sublimating the organic raw material 18 in the vaporization sublimation chamber 12 constant, the source gas fed into the source gas transport pipe 13 Can be kept constant. Thus, by monitoring the pressure in the vaporization sublimation chamber 12 in the vaporization sublimation step as described above, a decrease in the organic raw material 18 can be detected as a decrease in pressure, and replenishment can be performed before the organic raw material 18 is depleted. .
[0059]
The source gas transport step is performed in the source gas transport pipe 13. In the source gas transport step, the source gas is transported through the source gas transport pipe 13 using a carrier gas. The source gas transported through the source gas supply pipe 13 is discharged from the injector 23 into the chamber 11.
[0060]
In this source gas transporting step, if the flow rate of the carrier gas supplied in the above-described carrier gas introducing step is increased, the amount of the source gas to be transported can be increased. This makes it possible to increase the amount of the raw material gas supplied to the substrate 3 and improve the film forming speed on the substrate 3. As described above, in the organic vapor deposition method, the film formation rate can be controlled not by the vaporization or sublimation temperature of the organic raw material 18 but by the flow rate of the carrier gas, so that the film formation rate can be precisely controlled. It becomes.
[0061]
In the source gas transporting step, the temperature of the source gas is controlled by heating the source gas transport tube 13 by the heater 24 in order to avoid solidification of the organic source due to a decrease in the temperature of the source gas in the source gas transport tube 13.
[0062]
The organic film deposition step is performed in the chamber 11. In the organic film deposition step, the source gas transported through the source gas transport pipe 13 in the above-described source gas transport step and released from the injector 23 is adsorbed on the substrate 3 to form an organic film.
[0063]
The source gas has a temperature of, for example, about 250 ° C. in order to keep the organic source in a gaseous state. Therefore, the temperature of the substrate 3 to which the source gas is supplied rises. Therefore, in the organic film deposition step, cooling water is supplied to the substrate holder 2 through the cooling pipe 14, and temperature control is performed so that the substrate 3 maintains a temperature of, for example, about room temperature.
[0064]
As described above, since the organic film can be formed while maintaining the temperature of the substrate 3 at around room temperature, the organic raw material adsorbed on the substrate 3 is rapidly cooled from a high-temperature gas state to be amorphous or amorphous. A high quality microcrystalline organic film is formed. Thereby, it is possible to prevent the deterioration of the electric characteristics and the deterioration of the optical characteristics due to the crystallization of a part or all of the organic film deposited on the substrate 3. Further, since the temperature of the substrate 3 can be kept at about room temperature, it is possible to use a heat-sensitive plastic substrate as the substrate 3. Therefore, in the thin-film forming apparatus 1 of the present embodiment, it is possible to manufacture an organic EL light-emitting element constituting a flexible display.
[0065]
Depending on the type of the organic raw material, a high-quality organic film may be formed when the temperature of the substrate 3 is set to about 100 ° C., so that a heating means such as a heater (not shown) is incorporated in the substrate holder 2. It is also possible. Further, both a cooling means using a cooling pipe 14 as shown in FIG. 2 and a heating means using a heater (not shown) are incorporated in the substrate holder 2 and either one is selectively used in accordance with the organic material to be used. It may be.
[0066]
The evacuation process is performed in the chamber 11. In the evacuation process, prior to each of the above-described processes, the chamber 11 in which the substrate 3 is housed can control the flow of the source gas 10. ² -10 ³ Maintain a low vacuum of about Pa. Further, the residual gas generated in the organic film deposition step is exhausted.
[0067]
The film distribution is more uniform when the film is formed while the substrate 3 is rotated, for example, than when the film is formed by fixing the position of the substrate 3 with respect to the injector 23. Therefore, in the thin film forming apparatus 1 shown in FIG. 2 or the like, a mechanism for driving the substrate holder 2 may be provided.
[0068]
FIG. 6 is a cutaway perspective view of the chamber 2 showing an operation example of the substrate 3. Since various shapes are conceivable for the shape of the substrate holder 2 and the chamber 11, the chamber 11 having a circular cross section in FIG. 6A and the chamber 11 having a rectangular cross section in FIG. Is shown. In the configuration shown in FIG. 6A, the substrate holder 2 has a mechanism that is driven by driving means (not shown) about the shaft 2b and rotates. The substrate 3 is rotated such that the center of the substrate 3 coincides with the rotation center O. Is provided. Here, the center of the substrate 3 is an intersection of diagonal lines. Thus, when the substrate holder 6 is rotated by a driving unit (not shown), the substrate 3 rotates around the rotation center O of the substrate holder 6 as an axis.
[0069]
Then, the source gas discharged from the injector 23 is diffused and supplied onto the substrate 3, so that the substrate 3 rotates (rotates), so that the film distribution of the organic film formed on the substrate 3 becomes uniform.
[0070]
In the configuration shown in FIG. 6B, a substrate holder 2 that is slid and driven by a driving mechanism 27 using a linear motor or the like is provided in the chamber 11. In the above configuration, in the organic film deposition step, the raw material gas is released from the injector 23 while sliding the substrate holder 2. Thus, the source gas can be supplied to the entire surface of the substrate 3 to deposit the organic source, so that the film distribution in the plane of the substrate 3 and in the pixels is uniform. Although not shown, the rotation mechanism of FIG. 6A and the slide mechanism of FIG. 6B may be combined so that the substrate 3 rotates while sliding.
[0071]
As described above, by performing the rotation operation and the slide operation of the substrate 3 with respect to the injector 23, the uniformity of the film distribution in the plane of the substrate 3 and in the pixels is improved. Also, when the substrate 3 is operated, a higher quality organic film can be formed by providing a mechanism for cooling the substrate 3 as shown in FIG.
[0072]
When the substrate 3 is rotated or slid, the mask 5 is held by the permanent magnet 4 as shown in FIG. 1, thereby suppressing the occurrence of patterning failure due to the displacement of the mask 5.
[0073]
FIGS. 7A and 7B are explanatory views showing a main configuration of a thin film forming apparatus according to the second embodiment. FIG. 7A is a perspective view, and FIG. 7B is a side view. In the thin film forming apparatus of the second embodiment, a mask clamping mechanism 31 as a gripping means for fixing the mask 5 from the front side of the substrate holder 2 is added as the mask fixing device 30.
[0074]
The mask clamp mechanism 31 includes a frame portion 32 in which a slit forming portion (not shown) of the mask 5 is opened, and a clamp slide mechanism 33 that slides the frame portion 32. Here, the frame portion 32 is entirely made of a magnetic material, or has a structure in which a member made of a magnetic material is partially provided.
[0075]
Hereinafter, an operation of attaching the substrate 3 and the mask 5 to the substrate holder 2 in the thin film forming apparatus according to the second embodiment will be described. Before attaching the substrate 3 and the mask 5, the slide mechanism 7 on the permanent magnet 4 side moves the permanent magnet 4 to a position away from the substrate holder 2, as shown in FIG.
[0076]
As described above, the substrate 3 is first set on the substrate holder 2 with the permanent magnet 4 separated from the substrate holder 2. The substrate 3 is positioned with respect to the substrate holder 2 by setting the substrate 3 with its sides abutting the positioning pins 2a shown in FIG.
[0077]
Next, as shown in FIG. 5B, alignment is performed while holding the mask 5 on the substrate 3 set on the substrate holder 2. For example, while monitoring the position of the mask 5 with the CCD camera 26, the mask 5 is rotated on a plane horizontal to the surface of the substrate 3 and slid in the X and Y directions to position the mask 5 with respect to the substrate 3. Do.
[0078]
Then, as shown in FIG. 5C, the positioned mask 5 is set on the substrate 3, and the mask 32 is pressed by the frame 32 as shown in FIG. At this time, since the permanent magnet 4 remains retracted to a position that does not affect the alignment of the mask 5, it is not necessary to perform positioning against the magnetic force of the permanent magnet 4 at the time of alignment of the mask 5, and accurate positioning is performed. Can be performed. Also, when the mask 5 is set on the substrate 3, the mask 5 is not pulled in the direction of the substrate 3 by the magnetic force of the permanent magnet 4, so that the mask 5 can be set on the substrate 3 while maintaining the position determined by the alignment.
[0079]
Next, as shown in FIG. 5D, the permanent magnet 4 is moved by the slide mechanism 7 in a direction approaching the substrate holder 2. The moving speed v at this time may be constant. When the distance between the substrate holder 2 and the permanent magnet is r, vｒr ² May be changed according to the following relationship. That is, it is preferable to perform control such that the moving speed is reduced as the distance between the substrate holder 2 and the permanent magnet 4 is reduced.
[0080]
As described above, by controlling the speed so that the moving speed of the permanent magnet 4 decreases as the distance from the substrate holder 2 decreases, the frame portion 32 and the mask 5 are slowly brought into close contact with the substrate 3, Can be fixed. Thereby, it is possible to prevent the displacement of the mask 5 that occurs when the substrate 3 and the mask 5 are fixed. Further, when the distance between the permanent magnet 4 and the substrate holder 2 is large, the influence of the magnetic force is weak. Therefore, by increasing the moving speed, it is possible to prevent an increase in the time required for fixing the mask 5. Then, as shown in FIG. 5E, when the permanent magnet 4 is moved to a position where it is brought into close contact with the back surface of the substrate holder 2, the movement of the permanent magnet 4 by the slide mechanism 7 is stopped. Thereby, the frame portion 32 is attracted to the permanent magnet 4 and the mask 5 is held on the front surface side of the substrate 3.
[0081]
As described above, by providing the mask clamp mechanism 31, even when the mask 5 is made of a non-magnetic material, the mask 32 can be fixed by attracting the frame portion 32 with the permanent magnet 4.
[0082]
Although the thin film forming apparatuses of the first and second embodiments described above have been described with a configuration using the organic vapor deposition method, a thin film forming apparatus in which a mask fixing device is incorporated is as shown in FIG. It can also be applied to a simple vacuum evaporation apparatus.
[0083]
【The invention's effect】
As described above, the present invention provides a thin film forming apparatus for forming a thin film by placing a mask for pattern formation on a substrate, holding means for holding the substrate, and providing the holding means on the back side of the substrate holding surface of the holding means. A permanent magnet that attracts the mask on the substrate held by the holding means; and a moving means that moves the permanent magnet toward and away from the mask.
[0084]
With this, the permanent magnet is held at a position away from the mask on the substrate, and by gradually bringing the permanent magnet closer to the mask, the magnetic force of the permanent magnet can be gradually exerted on the mask and attracted, Mask displacement is prevented. In addition, the occurrence of patterning failure can be suppressed by preventing the displacement of the mask.
[0085]
In addition, the mask may be held by a permanent magnet and a mechanism for changing the position of the permanent magnet may be provided, so that the configuration of the apparatus can be simplified, and the cost and size of the apparatus can be reduced. it can.
[Brief description of the drawings]
FIG. 1 is a perspective view illustrating a main configuration of a thin film forming apparatus according to a first embodiment.
FIG. 2 is an overall configuration diagram of a thin film forming apparatus according to the present embodiment.
FIG. 3 is a perspective view of a mask fixing device incorporated in the thin film forming apparatus shown in FIG.
FIG. 4 is a side view of the mask fixing device.
FIG. 5 is an explanatory diagram showing a process of attaching a substrate and a mask.
FIG. 6 is a cutaway perspective view of a chamber showing an operation example of a substrate.
FIG. 7 is a perspective view illustrating a main configuration of a thin film forming apparatus according to a second embodiment.
FIG. 8 is an explanatory view showing an example of the structure of the organic EL element.
FIG. 9 is a plan view showing an outline of an organic EL color display.
FIG. 10 is a perspective view of a main part of an organic EL color display.
FIG. 11 is an explanatory diagram showing a basic configuration of a vacuum evaporation apparatus.
FIG. 12 is an explanatory view of a conventional mask fixing device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Thin film forming apparatus, 2 ... Substrate holder, 2a ... Positioning pin, 2b ... Shaft, 3 ... Substrate, 4 ... Permanent magnet, 4a ... Hole part, 5 ... ..Mask, 5a ... slit, 6 ... mask fixing device, 7 ... slide mechanism, 7a ... feed screw, 8 ... support base, 8a ... nut part, 11 ... Chamber, 12: vaporization sublimation chamber, 13: source gas transport pipe, 14: cooling pipe, 15: pressure gauge, 16: exhaust pipe, 17: source container, 18 ... -Organic raw material, 19-Pressure gauge, 20-Supply pipe, 21-Flow controller, 22-Tank, 23-Injector, 24-Heater, 25a, 25b-Temperature Sensor, 26: CCD camera, 27: Drive mechanism, 30: Mask fixing device, 31 ... Mask clamp mechanism, 32 ... frame portion, 33 ... clamp slide mechanism

Claims (11)

In a thin film forming apparatus for placing a mask for pattern formation on a substrate and forming a thin film,
Holding means for holding the substrate,
A permanent magnet that is provided on the back side of the substrate holding surface of the holding unit and attracts the mask on the substrate held by the holding unit;
Moving means for moving the permanent magnet in a direction approaching and moving away from the mask. 2. The thin film forming apparatus according to claim 1, wherein the moving unit fixes the mask by gradually bringing the permanent magnet closer to the mask placed on the substrate. 3. 3. The thin film forming apparatus according to claim 2, wherein the moving unit changes a moving speed of the permanent magnet according to a distance from the mask. 2. The thin film forming apparatus according to claim 1, further comprising: a holding unit that holds the mask by being attracted to the permanent magnet, on the substrate holding surface side of the holding unit. A chamber containing the holding means,
Vaporization sublimation means for generating a raw material gas by changing an organic raw material into a gas phase,
Carrier gas introduction means for mixing the source gas and the carrier gas,
Source gas transport means for transporting the source gas using the carrier gas,
Discharging means for discharging the source gas transported by the source gas transporting means into the chamber;
2. The thin film forming apparatus according to claim 1, further comprising an exhaust unit that exhausts the chamber. 2. The thin film forming apparatus according to claim 1, wherein the holding unit rotates the substrate to which the mask is attached. 2. The thin film forming apparatus according to claim 1, wherein the holding unit slides the substrate on which the mask is attached. 2. The thin film forming apparatus according to claim 1, wherein the holding unit rotates the substrate to which the mask is attached while sliding the substrate. 2. The thin film forming apparatus according to claim 1, wherein said holding means includes a cooling means for cooling a back surface of said substrate to which said mask is attached. 2. The thin film forming apparatus according to claim 1, wherein said holding means includes a heating means for heating a back surface of said substrate to which said mask is attached. 2. The thin film forming apparatus according to claim 1, wherein said holding means includes a cooling / heating means for cooling or heating a back surface of said substrate to which said mask is attached.

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