JP6548761B2 - Vapor deposition apparatus, vapor deposition method, and method of manufacturing organic EL display device - Google Patents

Description

  The present invention relates to, for example, a vapor deposition apparatus for vapor depositing an organic layer of an organic EL display device, a vapor deposition method, and a method of manufacturing the organic EL display device.

  For example, when an organic EL display device is manufactured, a drive element such as a TFT is formed on a support substrate, and an organic layer is laminated corresponding to each pixel on the electrode. This organic layer is weak to moisture and can not be etched. Therefore, the organic layers are stacked by arranging a supporting substrate (substrate to be evaporated) and a deposition mask in an overlapping manner, and depositing an organic material through the opening of the deposition mask. Then, the necessary organic material is laminated only on the electrode of the necessary pixel. If the deposition substrate and the deposition mask are not as close as possible, the organic layer is not formed only in the precise region of the pixel. If the organic material is not deposited only in the correct pixel area, the displayed image is likely to be blurred. Therefore, a magnetic chuck is used to make the deposition substrate approach the deposition mask by using a magnetic substance for the deposition mask and interposing the deposition substrate between the permanent magnet or electromagnet and the deposition mask (for example, a magnetic chuck is used) Patent Document 1).

Japanese Patent Application Publication No. 2008-024956

  Conventionally, a metal mask has been used as a vapor deposition mask, but in recent years, a hybrid vapor deposition mask in which the periphery of the mask opening formed of a resin film is supported by a metal support layer to form a finer opening. Tend to be used. Like a hybrid mask, a deposition mask with few magnetic substances can not perform sufficient adsorption unless it has a stronger magnetic field (magnetic field).

  As described above, if the adsorption is not sufficient, the accessibility of the deposition substrate and the deposition mask is reduced. A strong magnetic field is required to draw the deposition mask sufficiently toward the deposition substrate. When a permanent magnet is used as a magnet of a magnetic chuck, when the magnetic field is strong, alignment between the deposition target substrate and the deposition mask becomes difficult. On the other hand, when an electromagnet is used, a magnetic field can be applied after alignment without applying a magnetic field during alignment, so that alignment between the deposition substrate and the evaporation mask is facilitated. However, if a strong magnetic field is applied after aligning the deposition substrate and the deposition mask using an electromagnet, performance defects and property deterioration may occur in the TFT of the deposition substrate and the laminated film of the organic material. The inventor found out. In particular, in the case of using a hybrid type vapor deposition mask, a strong magnetic field is required to perform sufficient adsorption. In this case, the strengthening magnetic field is at most twice as large as the large electromagnet is required. However, even in the case of the electromagnet in the case of the conventional metal mask, the change in magnetic flux at the time of current injection is very large, and when the current increases, the change in magnetic flux becomes more remarkable. The inventors of the present invention have found that defects in the TFT formed on the deposition substrate and deterioration of the organic layer can be prominently caused by the electromagnetic induction generated at the time of current injection.

  The present invention has been made to solve such a problem, and even if an electromagnet is used as a magnet of a magnetic chuck, defects or deterioration of elements such as TFTs formed on a deposition substrate, and organic matter. An object of the present invention is to provide a vapor deposition apparatus and a vapor deposition method that suppress the deterioration of the layer characteristics.

  Another object of the present invention is to provide a method of manufacturing an organic EL display device excellent in display quality by using the above vapor deposition method.

  An evaporation apparatus according to an embodiment of the present invention includes an electromagnet, a substrate holder which is provided at a position facing one magnetic pole of the electromagnet, and holds the deposition substrate, and the deposition substrate held by the substrate holder. A vapor deposition mask provided at a position facing the opposite surface to the electromagnet and having a magnetic body, a vapor deposition source provided opposite to the vapor deposition mask for vaporizing or subliming a vapor deposition material, and a power supply circuit for driving the electromagnet , And the electromagnet includes a first electromagnet generating a magnetic field directed in a first direction, and a second electromagnet generating a magnetic field reverse to the first direction. ing.

  In the vapor deposition method according to one embodiment of the present invention, the electromagnet, the vapor deposition substrate, and the vapor deposition mask having a magnetic material are stacked, and the vapor deposition substrate and vapor deposition are performed by energizing the electromagnet from the power supply circuit. Depositing the deposition material on the deposition target substrate by scattering the deposition material from the deposition source placed apart from the deposition mask, and the step of: And a second electromagnet generating a magnetic field opposite to the first direction, wherein the first and second electromagnets are simultaneously energized. The second electromagnet is turned off.

  In the method of manufacturing an organic EL display device according to one embodiment of the present invention, an organic layer is formed by forming at least a TFT and a first electrode on a support substrate, and depositing an organic material on the support substrate using the vapor deposition method. Forming a laminated film, and forming a second electrode on the laminated film.

  According to the vapor deposition apparatus and the vapor deposition method of one embodiment of the present invention, it is possible to suppress the failure or deterioration of an element such as a TFT formed on the vapor deposition substrate and the deterioration of the characteristics of the organic layer.

It is a figure explaining the example of composition of the electromagnet of one embodiment of the present invention. It is a figure explaining the other example of composition of the electromagnet of one embodiment of the present invention. It is a figure which shows the relationship between the electromagnet of a vapor deposition apparatus, a vapor deposition board | substrate, and a vapor deposition mask. It is an enlarged view of an example of a vapor deposition mask. It is a figure which shows typically the magnetic field which generate | occur | produces with an electromagnet. It is a figure which shows typically the magnetic field which generate | occur | produces with the conventional electromagnet. It is a figure which shows the relationship between magnetic flux and the space | interval of a vapor deposition board | substrate and a vapor deposition mask. It is a figure which shows the vapor deposition process by the manufacturing method of the organic electroluminescence display of this invention. It is a figure which shows the state on which the organic layer was laminated | stacked by the manufacturing method of the organic electroluminescence display of this invention.

  Next, a deposition apparatus and a deposition method according to an embodiment of the present invention will be described with reference to the drawings. As for the vapor deposition apparatus of this embodiment, the structural example of the whole is shown by FIG. 3A, and the structural example of an example of the electromagnet 3 is shown by FIG. As shown in FIG. 3A, the electromagnet 3, the substrate holder 29 for holding the deposition target substrate 2 to be provided at the position facing the one magnetic pole of the electromagnet 3, and the deposition target substrate 2 held by the substrate holder 29. It includes a deposition mask 1 provided on the opposite side of the electromagnet 3 and having a magnetic body, and a deposition source 5 provided opposite to the deposition mask 1 to vaporize or sublime the deposition material. Furthermore, as shown in FIGS. 1 and 2, the electromagnet 3 generates a first electromagnet 3A that generates a magnetic field (magnetic field) in a first direction, and a magnetic field (magnetic field) that is reverse to the first direction. And a second electromagnet 3B.

  Here, the inventor uses a permanent magnet in place of the electromagnet 3 in the configuration as shown in FIG. 3A in order to obtain the adhesion (good accessibility) between the vapor deposition mask 1 and the vapor deposition substrate 2. The permanent magnet, the touch plate 4, the deposition target substrate 2 and the deposition mask 1 were stacked, and the relationship between the magnetic flux and the gap between the deposition mask 1 and the deposition target substrate 2 was examined. The results are shown in FIG. As the permanent magnet, a sheet magnet was used in which a magnetic field was generated on one side and no magnetic field was generated on the other side (magnetic field is zero). Three permanent magnets having different magnetic fields were prepared, and the three permanent magnets were exchanged to examine the relationship between the magnetic field on the surface of the deposition mask 1 and the gap between the deposition substrate 2 and the deposition mask 1. A hybrid mask was used as the deposition mask 1. From the results of confirming the relationship between the gap and the deposition state of the organic material, it is understood that the smaller the gap between the deposition substrate 2 and the deposition mask 1 is, the better the deposition state is 3 μm or less. There is.

  Therefore, it is understood from the research results shown in FIG. 4 that the larger the magnetic flux density B (B = μH; μ is the magnetic permeability, H is the magnetic field strength) of the magnet, the better. However, as described above, when the deposition mask 1 is adsorbed by the electromagnet 3 with a strong magnetic field and the deposition substrate 2 and the deposition mask 1 are sufficiently brought close to each other, the present inventor is formed on the deposition substrate 2. It has been found that elements such as TFT may be damaged, performance may be degraded, and further, the characteristics of the organic layer may be degraded. As a result of further intensive investigations and investigations of the cause, the inventor of the present invention has found that when the current is applied to the electromagnetic coil (hereinafter also referred to as a first electromagnetic coil) 32 of the electromagnet 3, the electromotive force is caused by electromagnetic induction. It has been found that an overcurrent flows in a circuit such as a TFT (not shown) formed on the deposition substrate 2. Then, the inventor of the present invention destroys or degrades the TFT or the organic layer 25 (see FIG. 6) by Joule heat generated in the electrode 22 (see FIG. 5 or 6) due to the overcurrent or the overcurrent. I found out to

That is, for example, as an example of the conventional electromagnet 3 is shown in FIG. 3D, when current flows through the electromagnetic coil 32 of the electromagnet 3, the magnetic field H is generated in a fixed direction according to the right-handed screw law. The magnetic field H has the property of adsorbing the magnetic substance. However, when applying this current, the current flows rapidly (almost instantaneously), and the magnetic flux Φ (Φ = BS = μHS; S is the cross-sectional area of the core 31) generated by the electromagnet 3 rapidly increases. When the magnetic flux Φ changes rapidly, an electromotive force corresponding to V∝-dΦ / dt is generated. When current is applied to the electromagnetic coil 32, the time (rise time) Δt until the current reaches a predetermined current from 0 depends on the magnitude of the self inductance of the electromagnet 3, but in the case of the normal electromagnet 3, 10 μs It will be about (seconds). Since Δt is very small, the minute time dt can be approximated by this Δt. Therefore, for example, when a magnetic flux of about 300 gauss is changed at this time Δt, an electromotive force of about 30 MV is generated by electromagnetic induction. The electromotive force causes a current to flow in the closed circuit in the vapor deposition substrate 2 to damage the TFT and the like. The electromotive force V becomes larger as the change of the magnetic flux 大 き い becomes larger, as understood from the above equation. Since the electromagnetic coil 32 of the electromagnet 3 has a self-inductance, the change of the magnetic flux 、 is suppressed, but a large induced electromotive force of about 30 MV as described above still occurs, and such an induced electromotive force causes the element to be damaged or the characteristic deteriorated. It shows that it affects. Furthermore, heat represented by Q = V ² · t / R is generated as the amount of Joule heat Q (J) (R: electrical resistance (Ω) of the closed circuit in the deposition target substrate 2). Due to the generation of Joule heat, organic materials that are weak to high temperatures may degrade their properties.

  Then, as a result of repeated investigations by the inventor of the present invention, as a result of investigation, the magnetomotive force (N · I; N: number of turns of the coil, I: magnitude of current flowing to the electromagnetic coil 32) generated by the electromagnet 3 gradually increases It has been found that the change in the generated magnetic flux can be slowed down by solving such changes, and such problems can be solved. That is, the change of the magnetic flux B is only generated when the current is supplied to the electromagnetic coil 32 of the electromagnet 3 and when the current is turned off, and when the current is stabilized, the magnetic field corresponding to the current and the number of turns of the coil It occurs stably and keeps adsorbing the magnetic material. Therefore, the change of the magnetic flux B is only at the time of turning on and off of the current, and the time is about 10 μs as described above, for example, if it becomes a predetermined current in about 1 ms (milliseconds) Does not occur. Therefore, for example, as shown in FIG. 3C, a part of the first electromagnetic coil 32 is wound in the opposite direction, and the first electromagnet 3A and the second electromagnet 3B in the part of the opposite winding are wound. The inventors have found that the problem due to the generation of electromagnetic induction can be eliminated by forming the second electromagnet 3B and turning off the second electromagnet 3B after the current is applied.

Although a predetermined magnetic field H is generated by the first electromagnet 3A, a current also flows to the second electromagnet 3B by the injection of the current. Since the second electromagnetic coil 35 of the second electromagnet 3B is continuous with the electromagnetic coil 32 of the first electromagnet 3A, current flows simultaneously. However, in the second electromagnetic coil 35 of the second electromagnet 3B, the winding direction of the coil and the first electromagnetic coil 32 of the first electromagnet 3A are reversed. Therefore, the magnetic field H ₀ generated by the second electromagnet 3B is a downward drawing becomes opposite with the magnetic field H of the first electromagnet 3A. As a result, the magnetic field H generated by the first electromagnet 3A described above is cancelled, and the generated magnetic field at the time of current injection becomes (H−H ₀ ). As described above, since the electromotive force due to electromagnetic induction is proportional to the speed of change of the magnetic flux B, that is, the magnetic field H, if the magnetic field (H-H ₀ ) becomes smaller, the electromotive force due to electromagnetic induction becomes smaller. As a result, the influence of electromagnetic induction is reduced. Therefore, the influence of electromagnetic induction at the time of current injection can be avoided.

  For example, if the number of turns of the second electromagnetic coil 35 of the second electromagnet 3B is set to about half of that of the first electromagnet 3A, the generated magnetic field at the time of current injection is about half. That is, the electromotive force by electromagnetic induction also becomes about half. Then, the second electromagnet 3B is turned off after the current is applied, so that the magnetic field H for the original adsorption of the deposition mask 1 is obtained. Therefore, the adsorption of the deposition mask 1 is not affected at all. The number of turns of the second electromagnetic coil 35 of the second electromagnet 3B may be at most 1/3 to 2/3 of the number of turns of the electromagnetic coil 32 of the first electromagnet 3A. If the reverse electromagnetic induction generated by turning off the second electromagnet 3B becomes a problem, the second electromagnetic coil 35 of the second electromagnet 3B is provided with a plurality of terminals and turned off in stages. You can also

  In addition, as the second electromagnet 3B, as shown in FIG. 3C, the first electromagnet 3A may be extended without extending the same core 31 as the first electromagnet 3A and winding the second electromagnetic coil 35. Or the first electromagnet 3A is an air-core electromagnet, and the second electromagnet 3B whose winding direction is reversed is inserted inside the first electromagnet 3A or the air-core The first electromagnet 3A may be inserted into the inner periphery of the second electromagnet 3B. In the following, the relationship between the two electromagnets 3A, 3B with different directions of the magnetic field will be described in more detail.

Example 1
The example shown in FIG. 1 has the same configuration as the example shown in FIG. 3C described above, but this example is a cross-sectional view of the electromagnet 3 and the current to the first and second electromagnetic coils 32 and 35 is The directions are indicated by x (downward) and · (upward). Furthermore, in this example, a plurality of terminals 35a, 35b, 35c are formed in the second electromagnetic coil 35 of the second electromagnet 3B, and the terminals can be switched to gradually reduce the second electromagnet 3B. Since the electric resistances of the first and second electromagnetic coils 32 and 35 are very small, even if the second electromagnetic coil 35 of the second electromagnet 3B is turned off with respect to the voltage of the power supply circuit 6, The current of the electromagnet 3A of 1 hardly changes. Therefore, the magnetic field H generated by the first electromagnet 3A can be obtained as it is. On the other hand, at the time of current injection (when the main switch 60 is on), the second electromagnetic coil 35 also operates. As described above, since the electromagnetic coil 32 of the first electromagnet 3A and the second electromagnetic coil 35 of the second electromagnet 3B are continuous, current flows simultaneously in both. However, since the second electromagnetic coil 35 has the reverse winding direction, it generates a reverse magnetic field H ₀ . Therefore, the magnetic field generated at the time of current injection (when the main switch 60 is on) becomes small, and the adverse effect due to the electromagnetic induction can be prevented.

  Since the number of turns of the second electromagnetic coil 35 is smaller than that of the electromagnetic coil 32 of the first electromagnet 3A, the influence of the electromotive force in the opposite direction of the electromagnetic induction that can be generated by turning off the second electromagnet 3B is small. However, if the cutting of the second electromagnet 3B is performed stepwise as necessary, the influence can be reduced as much as possible. The stepwise OFF can be obtained by forming a plurality of terminals 35 a, 35 b, 35 c in the second electromagnetic coil 35 as shown in FIG. 1 and sequentially switching them by the changeover switch 61. The off speed of the second electromagnet 3B is not limited to a short time of μ seconds in time, and for example, the slide switch may be manually switched. To put it in an extreme way, there is no problem even if it takes time in the order of seconds or minutes. Moreover, it is possible to incorporate a circuit that slides the changeover switch 61 in conjunction with the main switch 60 for turning on the current.

  For example, as shown in FIG. 1, the terminals 35a, 35b and 35c are formed for cutting off the second electromagnet 3B, and the switch 61 is connected to the terminal 35c at the time of turning on the current. The operation of the second electromagnet 3B can be gradually reduced by sliding the terminals connected to the changeover switch 61 with the terminals 35b, 35a after the current is applied. The number of terminals is not limited to three, and any number may be formed.

  Also, for example, when aligning the deposition substrate 2 and the deposition mask 1, the two electromagnets 3A and 3B are operated in a weak magnetic field and the second electromagnet 3B is moved after the setting is completed. It may be cut gradually. By doing so, it is possible to align the deposition substrate 2 and the deposition mask 1 with a certain degree of proximity, and accurate alignment is easily performed. Moreover, even when a magnetic field is applied after alignment, the magnetic field is gradually applied, and mutual positional deviation and the like hardly occur.

  With such a structure in which the second electromagnets 3B are juxtaposed, even when the deposition is finished and the first electromagnet 3A is turned off, an operation reverse to that at the time of current application, that is, switching of the second electromagnet 3B After switching the switch 61 sequentially from the terminal 35a to the terminal 35c to operate the second electromagnet 3B, the main switch 60 of the power supply circuit 6 can be turned off. By doing so, the magnetic field of the electromagnet 3 can be easily released without any influence of the electromagnetic induction even at the time of removing the deposition substrate 2. That is, even when the current of the electromagnet 3 is turned off, the same problem of electromagnetic induction as that at the time of current injection is likely to occur, but according to the present embodiment, the problem can be solved.

  In the above example, the core 31 is made longer to form the second electromagnet 3B. However, as described above, the present invention is not limited to this example, but if electrical insulation between coils is obtained, the second electromagnet 3A is used. Multiple second electromagnetic coils 35 may be wound on the electromagnetic coil 32. Also, the second electromagnet 3B may be formed inside or on the outer periphery of the first electromagnet 3A. In any case, it is preferable that the electromagnetic coil 32 of the first electromagnet 3A and the second electromagnetic coil 35 be connected. This is because current can be applied simultaneously.

(Example 2)
In the example shown in FIG. 1 described above, the first and second electromagnets 3A, 3B are formed by changing the winding direction of the first and second electromagnetic coils 32, 35 wound around the same core 31. ing. However, two types of electromagnetic coils do not have to be wound around the same core. For example, as shown in FIG. 2, the first electromagnet 3A (3A1, 3A2) is formed of a plurality of unit electromagnets 3A1, 3A2, and the second electromagnet 3B is formed on the outer periphery of a part or the whole of the unit electromagnets. It may be done. In this example, the third electromagnetic coil 38 is wound around the cylinder 36 provided outside the two unit electromagnets 3A1 and 3A2 so as to generate a magnetic field in the opposite direction to the first electromagnet 3A. ing. Although the electromagnetic coils 32 of the first electromagnets 3A1 and 3A2 are connected in series, they may be connected in parallel. However, the winding directions are formed in the same direction. On the other hand, it is preferable that the third electromagnetic coil 38 of the second electromagnet 3B is connected in series opposite to the electromagnetic coil 32 of the first electromagnet 3A. This is because it is necessary to simultaneously apply current.

  Also in the example shown in FIG. 2, as in the case of FIG. 1, the third electromagnetic coil 38 is provided with a plurality of terminals 38a, 38b and 38c, and the connection is switched by the changeover switch 61. ing. The other configuration is the same as the example shown in FIG. 1 described above, and the same reference numerals are given to the same parts, and the description thereof is omitted.

  As shown in FIG. 3A (the power supply circuit 6 is not shown), the vapor deposition apparatus according to one embodiment of the present invention has the electromagnet 3 mounted on the touch plate 4 and the surface of one of the magnetic poles of the electromagnet 3. A substrate holder 29 provided to hold the deposition substrate 2 via the touch plate 4, a deposition mask 1 provided on the opposite surface of the deposition substrate 2 held by the substrate holder 29 to the electromagnet 3, and a deposition mask And a deposition source 5 provided to be opposed to 1 and vaporize or sublime the deposition material. Then, the deposition mask 1 has a metal layer (metal support layer 12: see FIG. 3B) made of a magnetic material, and the electromagnet 3 attracts the metal support layer 12 of the deposition mask 1 to the electromagnetic coils 32, 35. It is connected to a power supply circuit 6 (see FIGS. 1 to 3C) for applying a current. The vapor deposition mask 1 is placed on the mask holder 15, and the substrate holder 29 and the support frame 41 holding the touch plate 4 are respectively lifted up. Then, the deposition target substrate 2 carried by a robot arm (not shown) is placed on the substrate holder 29, and the deposition target substrate 2 comes into contact with the deposition mask 1 by lowering the substrate holder 29. By further lowering the support frame 41, the touch plate 4 is superimposed on the deposition substrate 2. Further, the electromagnet 3 is mounted on the touch plate 4 by the operation of an electromagnet support member (not shown). The touch plate 4 is provided to flatten the deposition target substrate 2 and to cool the deposition target substrate 2 and the deposition mask 1 by circulating cooling water to the inside although not shown. The material and thickness of the touch plate 4 are determined in order to make the in-plane distribution of the magnetic field on the surface of the deposition mask 1 uniform.

  As the electromagnet 3 is schematically shown in FIG. 3C, first and second electromagnetic coils 32, 35 are wound around a core (magnetic core) 31 made of an iron core or the like. As described above, the second electromagnetic coil 35 is wound in the opposite direction to the electromagnetic coil 32 of the first electromagnet 3A. In FIG. 3A, for example, since the size of the vapor deposition mask 1 is about 1.5 m × 1.8 m, the unit electromagnet shown in FIG. 3C has a core 31 whose magnetic core 31 has a size of about 5 cm square. 3 shows a structure in which plural pieces (individual electromagnets are referred to as unit electromagnets) are arranged side by side according to the size of the deposition mask 1 (in FIG. 3A, the horizontal direction is scaled and the number of unit electromagnets is small Has been In the example shown in FIG. 3A, the first and second electromagnetic coils 32, 35 wound around each magnetic core 31 are connected in series, and a plurality of unit electromagnets are further connected in series. That is, the terminals 32b, 32c, and 32d of the unit electromagnets are connected in series, and the terminals 32a and 32e at both ends of the whole are connected to a power supply circuit (not shown). However, the electromagnetic coils 32 of the respective unit electromagnets may be connected in parallel. Also, several units may be connected in series. The current may be applied independently to a part of the unit electromagnet. However, it is preferable that the application of the current be simultaneously performed by a plurality of unit electromagnets.

  When a direct current flows through the electromagnetic coil 32 of the electromagnet 3, a magnetic field H is generated according to the right-hand screw rule, as shown in FIG. 3D. When a magnetic body is placed in the magnetic field H, magnetism is induced in the magnetic body according to the magnitude of the magnetic field H. As described above, the magnitude of the magnetic field H is determined by the product N · I of the number of turns N of the electromagnetic coil 32 and the magnitude I of the flowing current. Therefore, as the number of turns N of the electromagnetic coil 32 is increased and as the current I is increased, a larger magnetomotive force N · I can be obtained. However, since electromagnetic induction is generated according to the rate of change of N · I, as described above, if this change is too large, trouble occurs. Therefore, the above-mentioned second electromagnet 3B (see FIG. 3C) is formed so as not to cause the rapid change of the magnetic field H.

  In the example shown in FIG. 3A, the periphery of the unit electromagnet is fixed by a resin 33 such as silicone rubber, silicone resin, or epoxy resin. Although the resin 33 is not always necessary, the unit electromagnet can be fixed, and the handling of the electromagnet 3 becomes easy. However, in the present embodiment, since the electromagnet 3 is used in a vacuum state, the unit electromagnet is not fixed by the resin 33, but is allowed to cool the electromagnet 3 by heat radiation through the surroundings. May be At this time, it is preferable that the surface of the electromagnet 3 is a treated surface subjected to a blackening treatment such as an alumite treatment. In addition, the surface of the electromagnet 3 may be a roughened surface having a rough surface of 10 μm or more, for example, with an arithmetic average roughness Ra. That is, it is preferable that the surface roughening treatment is performed so that the surface roughness is 10 μm or more. When the surface roughness is Ra 10 μm, the surface area is 2.18 times as large as the ideal hemispherical portion formed by roughening. As a result, the heat dissipation effect is more than doubled. The cooling device is a broad sense including the device capable of performing such heat radiation or the above-mentioned water cooling as well as the electromagnet 3 having a surface on which the treated surface of the electromagnet 3 is formed. In the case where a large amount of current flows continuously, the electromagnet 3 may generate heat, and in such a case, it is preferable to cool the electromagnet 3 by water cooling. For example, it is conceivable to embed a water cooling pipe in the resin 33 described above and to allow the cooling water to flow.

  As shown in FIG. 3A, the deposition apparatus is provided with a substrate holder 29 and a mask holder 15. The substrate holder 29 is connected to a driving device (not shown) so that the peripheral portion of the deposition target substrate 2 can be held by a plurality of hook-like arms and can be vertically moved up and down. The deposition substrate 2 carried into the chamber by the robot arm is received by the hook-like arm, and the substrate holder 29 is lowered until the deposition substrate 2 approaches the deposition mask 1. An imaging device (not shown) is also provided so that alignment can be performed. The touch plate 4 is supported by the support frame 41, and is connected to the drive device that lowers the touch plate 4 to be in contact with the deposition target substrate 2 via the support frame 41. The deposition substrate 2 is flattened by lowering the touch plate 4. The deposition apparatus images the deposition substrate 2 while imaging the alignment marks formed on the deposition mask 1 and the deposition substrate 2 at the time of aligning the deposition mask 1 of the present embodiment with the deposition substrate 2. A fine movement device is also provided to move relative to the deposition mask 1. The alignment is performed in a state where the energization of the electromagnet 3 is stopped so that the deposition mask 1 is not attracted unnecessarily by the electromagnet 3. As described above, according to the present embodiment, by operating both of the first and second electromagnets 3A and 3B during this alignment, the alignment can be made closer under a weak magnetic field. It can be done. Although not shown, the vapor deposition apparatus is also equipped with an apparatus for putting the whole of the apparatus shown in FIG. 3A into a chamber and evacuating the inside.

  As shown in FIG. 3B, the vapor deposition mask 1 includes a resin film 11, a metal support layer 12, and a frame (frame) 14 formed around the resin film 11. The vapor deposition mask 1 is shown in FIG. 3A. Thus, the frame 14 is placed on the mask holder 15. A magnetic material is used for the metal support layer 12. As a result, a suction force is exerted between the electromagnet 3 and the magnetic core 31 of the electromagnet 3 so that the substrate 2 is held therebetween. The metal support layer 12 may be formed of a ferromagnetic material. In this case, the metal supporting layer 12 is magnetized by the strong magnetic field of the electromagnet 3 (in a state where the strong magnetization remains even if the external magnetic field is removed). When such a ferromagnetic material is used, when the electromagnet 3 and the vapor deposition mask 1 are separated, it is easier to cause a reverse current to flow through the electromagnet 3. Even in the case of generating a strong magnetic field for such magnetization, this embodiment does not cause any trouble due to electromagnetic induction. Moreover, when separating the electromagnet 3 and the vapor deposition mask 1, both of the first and second electromagnets 3A and 3B can be operated.

  As the metal support layer 12, for example, Fe, Co, Ni, Mn or an alloy of these may be used. Among them, Invar (an alloy of Fe and Ni) is particularly preferable because the difference in linear expansion coefficient with the vapor deposition substrate 2 is small, and there is almost no expansion due to heat. The thickness of the metal support layer 12 is about 5 μm to 30 μm.

  In FIG. 3B, the opening 11a of the resin film 11 and the opening 12a of the metal supporting layer 12 are tapered so as to be tapered toward the deposition target substrate 2 (see FIG. 3A). The reason is explained below. As the deposition source 5, various deposition sources 5 such as point, line, and plane may be used. For example, the entire surface of the vapor-deposited substrate 2 is obtained by scanning, for example, from the left end to the right end of the paper surface of the line type vapor deposition source 5 (extending in the direction perpendicular to the paper surface of FIG. 3A). Deposition is performed. As described above, the vapor deposition source 5 emits the vapor deposition material in the shape of a cross section of a cross section of the radiation beam of the vapor deposition material determined by the shape of the crucible, which spreads at a constant angle θ. The openings of the metal support layer 12 and the resin film 11 so that even the vapor-deposited particles in the vicinity of the side surface of the fan-shaped cross section reach the predetermined position of the vapor deposition substrate 2 without being blocked by the metal support layer 12 or the resin film 11 12a and the opening 11a are formed in a tapered shape. If the opening 12a of the metal support layer 12 is formed large, it may not be tapered.

(Deposition method)
Next, a deposition method according to an embodiment of the present invention will be described. In the vapor deposition method according to the embodiment of the present invention, as shown in FIG. 3A described above, the electromagnet 3, the vapor deposition substrate 2 and the vapor deposition mask 1 having a magnetic material are superposed and a power supply circuit 6 (FIG. 1 and 2) to attract the deposition substrate 2 and the deposition mask 1 by applying electricity to the electromagnet 3, and scattering of the deposition material 51 from the deposition source 5 disposed apart from the deposition mask 1. Depositing the deposition material 51 on the deposition substrate 2. The electromagnet 3 includes a first electromagnet 3A that generates a magnetic field in a first direction, and a second electromagnet 3B that generates a magnetic field in a direction opposite to the first direction. This is performed by turning off the second electromagnet 3B after the simultaneous energization of the electromagnets 3A and 3B. Before adsorption by the electromagnet 3, alignment between the deposition mask 1 and the deposition target substrate 2 may be performed.

  As described above, the deposition substrate 2 is superimposed on the deposition mask 1. The alignment between the deposition substrate 2 and the deposition mask 1 is performed as follows. The deposition target substrate 2 is moved relative to the deposition mask 1 while the alignment marks formed on the deposition target substrate 2 and the deposition mask 1 are observed with an imaging device. At this time, as described above, if both the first and second electromagnets 3A and 3B are operated, the deposition target substrate 2 and the deposition mask 1 can be brought close to each other by a weak magnetic field. However, alignment may be done without generating any magnetic field. By this method, the opening 11a of the vapor deposition mask 1 and the vapor deposition place of the vapor deposition substrate 2 (for example, in the case of the organic EL display described later, the pattern of the first electrode 22 of the device substrate) can be matched. After alignment, the second electromagnet 3B is turned off or the first and second electromagnets 3A, 3B are operated, and then the second electromagnet 3B is turned off. When the magnetic flux is stabilized, the magnetic flux is maintained, and almost no electromagnetic induction occurs, and a stable magnetic field is obtained. As a result, a strong attractive force is exerted between the electromagnet 3 and the vapor deposition mask 1 so that the vapor deposition substrate 2 and the vapor deposition mask 1 come close to each other.

  After that, as shown in FIG. 3A, the deposition material 51 is deposited on the deposition target substrate 2 by the scattering (vaporization or sublimation) of the deposition material 51 from the deposition source 5 disposed apart from the deposition mask 1. Specifically, as described above, although a crucible or the like or a line source formed in line is used, it is not limited thereto. For example, in the case of manufacturing an organic EL display device, a plurality of types of vapor deposition masks 1 having openings 11a formed in a part of the pixels are prepared, and the vapor deposition masks 1 are replaced to form organic layers in a plurality of vapor deposition operations. .

  According to this vapor deposition method, the magnetic field (magnetic flux) generated by the electromagnet 3 has a small magnetic field (magnetic field) due to the cancellation of the first electromagnet 3A and the second electromagnet 3B at the initial stage of application of current. The induced electromotive force is suppressed. However, when the second electromagnet 3B is turned off, the magnetic field becomes an original magnetic field, and a strong attraction force can sufficiently obtain the approach of the deposition substrate 2 and the deposition mask 1. The turning off of the second electromagnet 3B may not be performed at once but may be performed stepwise. As a result, the overcurrent flowing to the deposition target substrate 2 due to electromagnetic induction is suppressed, and the influence on the elements, the organic material, and the like formed on the deposition target substrate 2 can be suppressed.

  In the present embodiment, even when the electromagnet 3 is turned off in order to remove the deposition substrate 2 after the deposition is completed, the reverse of the method of supplying the current can be performed. That is, preferably, the electromagnet 3 is turned off after the second electromagnet 3B is operated. When the first electromagnet 3A is turned off, the current rapidly changes from a predetermined value to 0, so that an electromagnetic induction in the reverse direction to that at the time of current application occurs, but the electromagnetic induction can be controlled to be small. .

(Manufacturing method of organic EL display)
Next, a method of manufacturing an organic EL display device using the vapor deposition method of the above embodiment will be described. Since manufacturing methods other than the vapor deposition method can be performed by known methods, the method of laminating the organic layer by the vapor deposition method of the present invention will be mainly described with reference to FIGS.

  In the method of manufacturing an organic EL display device according to an embodiment of the present invention, a TFT, a planarization film and a first electrode (for example, an anode) 22 (not shown) are formed on a support substrate 21 and the deposition mask 1 is positioned on one surface thereof. The combination, the superposition, and the vapor deposition of the vapor deposition material 51 include forming the laminated film 25 of the organic layer using the aforementioned vapor deposition method. The second electrode 26 (see FIG. 6; cathode) is formed on the laminated film 25.

For example, although the support substrate 21 such as a glass plate is not completely illustrated, a drive element such as a TFT is formed for each RGB sub-pixel of each pixel, and the first electrode 22 connected to the drive element is flat. It is formed of a combination of a metal film such as Ag or APC and an ITO film on the oxide film. Between the sub-pixels, as shown in FIGS. 5 to 6, insulating banks 23 made of SiO _2, acrylic resin, polyimide resin or the like are formed to divide the sub-pixels. The above-mentioned vapor deposition mask 1 is aligned and fixed on the insulating bank 23 of such a support substrate 21. This fixing is performed, for example, by adsorption using an electromagnet 3 provided via the touch plate 4 on the side opposite to the deposition surface of the support substrate 21 as shown in FIG. 3A described above. As described above, since a magnetic material is used for the metal support layer 12 (see FIG. 3B) of the vapor deposition mask 1, when the electromagnet 3 applies a magnetic field, the metal support layer 12 of the vapor deposition mask 1 is magnetized to A suction force is generated between them. Even when the electromagnet 3 does not have the magnetic core 31, the electromagnet 3 is attracted by the magnetic field generated by the current flowing through the electromagnetic coil 32. At this time, as described above, when the current is applied, the first and second electromagnets 3A and 3B are operated at the same time, so that no sudden change in magnetic flux occurs. Therefore, the influence of the electromotive force by electromagnetic induction is suppressed. The openings 11 a of the vapor deposition mask 1 are formed smaller than the distance between the surfaces of the insulating banks 23. The organic material is prevented from adhering to the side wall of the insulating bank 23 as much as possible, and the reduction of the luminous efficiency of the organic EL display device is prevented.

  In this state, as shown in FIG. 5, the vapor deposition material 51 is scattered from the vapor deposition source (crucible) 5 in the vapor deposition apparatus, and the vapor deposition material is deposited only on the portion of the vapor deposition mask 1 where the opening 11a is formed. 51 is deposited, and the laminated film 25 of the organic layer is formed on the first electrode 22 of the desired sub-pixel. As described above, since the openings 11 a of the vapor deposition mask 1 are formed smaller than the distance between the surfaces of the insulating banks 23, the vapor deposition material 51 is less likely to be deposited on the side walls of the insulating banks 23. As a result, as shown in FIGS. 5 to 6, the laminated film 25 of the organic layer is deposited substantially only on the first electrode 22. In this deposition process, the deposition mask 1 may be sequentially replaced and performed for each sub-pixel. The deposition mask 1 may be used in which the same material is deposited simultaneously on a plurality of sub-pixels. When the deposition mask 1 is replaced, a power supply circuit is used to remove the magnetic field to the metal supporting layer 12 (see FIG. 3B) of the deposition mask 1 by the electromagnet 3 (see FIG. 3A) not shown in FIG. 6 (see FIGS. 1-2) are turned off. Also in this case, it is preferable that the power supply circuit 6 be turned off after the second electromagnet 3B is operated so that an element such as a TFT formed on the support substrate 21 can suppress the influence of electromagnetic induction.

Although the laminated film 25 of the organic layer is simply shown as one layer in FIGS. 5 to 6, the laminated film 25 of the organic layer may be formed of the laminated film 25 of a plurality of layers made of different materials. For example, as a layer in contact with the anode 22, a hole injection layer made of a material having good ionizing energy consistency that improves the hole injection property may be provided. On this hole injection layer, a hole transport layer capable of confining electrons (energy barrier) to the light emitting layer as well as improving stable transport of holes is formed of, for example, an amine material. Furthermore, a light emitting layer selected according to the light emission wavelength is formed thereon, for example, by doping red or green organic fluorescent material to Alq ₃ for red and green. Moreover, as a blue-based material, a DSA-based organic material is used. On the light emitting layer, an electron transport layer is formed by Alq ₃ or the like, which further improves electron injectability and transports electrons stably. A stacked film 25 of the organic layer is formed by stacking each of these layers by about several tens of nm. An electron injection layer may be provided between the organic layer and the metal electrode to improve the electron injection property of LiF or Liq. In the present embodiment, the film including these is also referred to as the laminated film 25 of the organic layer. Such a laminated film 25 may be affected by electromagnetic induction, but in the present embodiment, as described above, a magnetic field in the opposite direction to the first electromagnet 3A is generated when turning on or off the current. Since the second electromagnet 3B is operated, no sudden change of the magnetic field occurs. As a result, the influence of electromagnetic induction is suppressed.

  In the light emitting layer of the laminated film 25 of the organic layer, an organic layer of a material corresponding to each color of RGB is deposited. In addition, it is preferable that the hole transport layer, the electron transport layer, and the like be separately deposited of materials suitable for the light emitting layer, in consideration of light emission performance. However, in consideration of the material cost, the same material may be used in common to two or three colors of RGB. In the case where materials common to two or more sub-pixels are stacked, a deposition mask 1 in which an opening is formed in the common sub-pixel is formed. In the case where vapor deposition layers differ in individual sub-pixels, for example, each organic layer can be vapor-deposited continuously using one vapor deposition mask 1 in R sub-pixels. In addition, when a common organic layer is deposited for RGB, the organic layer of each sub-pixel is deposited to the lower side of the common layer, and an opening is formed in RGB at the common organic layer. The mask 1 is used to deposit the organic layers of all the pixels at one time. In the case of mass production, a number of chambers of the vapor deposition apparatus are arranged, and different vapor deposition masks 1 are mounted respectively, and the support substrate 21 (substrate 2 to be vapor deposited) moves through the respective vapor deposition apparatuses to be continuous. The deposition may be performed in a similar manner.

When the formation of the laminated film 25 of all the organic layers including the electron injection layer such as LiF layer is completed, the power supply circuit 6 of the electromagnet 3 is turned off and the electromagnet 3 is separated from the deposition mask 1 as described above. Thereafter, a second electrode (for example, a cathode) 26 is formed on the entire surface. The example shown in FIG. 6 is of the top emission type, in which light is emitted from the opposite surface to the support substrate 21 in the figure, so the second electrode 26 is made of a translucent material, for example, Mg—Ag of a thin film. It is formed of a eutectic film. Besides, Al or the like may be used. In the case of a bottom emission type in which light is emitted from the supporting substrate 21 side, ITO, In ₃ O ₄ or the like is used for the first electrode 22, and the second electrode 26 is a metal having a small work function, for example Mg, K, Li, Al or the like may be used. A protective film 27 made of, for example, Si ₃ N ₄ or the like is formed on the surface of the second electrode 26. In addition, this whole is sealed by the sealing layer which consists of glass, a resin film, etc. which are not shown in figure, and it is comprised so that the laminated film 25 of an organic layer may not absorb water. In addition, the organic layer can be made as common as possible, and a structure in which a color filter is provided on the surface side can be used.

(Summary)
(1) A vapor deposition apparatus according to a first embodiment of the present invention includes an electromagnet, a substrate holder provided at a position facing one magnetic pole of the electromagnet, and a substrate holder for holding a deposition substrate, and the substrate holder A deposition mask is provided at a position facing the opposite surface of the deposition substrate opposite to the electromagnet, and includes a deposition mask having a magnetic material, a deposition source provided opposite to the deposition mask, for evaporating or subliming a deposition material, and the electromagnet A power supply circuit for driving the first magnetic field, the electromagnet generates a magnetic field in a first direction, and a second electric field generates a magnetic field in a direction opposite to the first direction. It has an electromagnet.

  According to the deposition apparatus of one embodiment of the present invention, the deposition mask is adsorbed by the electromagnet, so that the deposition substrate and the deposition mask can be easily aligned without applying a magnetic field or with a weak magnetic field. It can be carried out. In addition, the application of the magnetic field can sufficiently bring the vapor deposition substrate and the vapor deposition mask sandwiched therebetween in close proximity. Moreover, in the present embodiment, the electromagnet includes the first electromagnet generating the magnetic field in the first direction, and the second electromagnet generating the magnetic field in the second direction opposite to the first direction. . Therefore, the magnetic field can be weakened by the operation of the second electromagnet when the current is applied. By doing so, even when current is supplied to the electromagnet, it is possible to suppress that an element such as a TFT formed on the deposition substrate is affected by the electromagnetic induction generated by the input of the current.

  (2) The power supply circuit avoids the influence of the electromagnetic induction at the start of the above-mentioned energization by having a changeover switch for turning off the energization of the second electromagnet after simultaneous energization of the first and second electromagnets. However, a desired magnetic field can be obtained during normal operation.

  (3) A first electromagnetic coil corresponding to the first electromagnet and a second electromagnetic coil corresponding to the second electromagnet are connected in series, and the second electromagnetic coil corresponds to the first electromagnetic The number of turns may be smaller than that of the coil, and may be opposite to that of the first electromagnetic coil. By connecting two electromagnetic coils in series, current can be applied to two electromagnets simultaneously. In addition, the second electromagnetic coil cancels part of the magnetic field generated by the first electromagnetic coil.

  (4) In addition to the terminals at both ends, the second electromagnetic coil has a third terminal in the middle of the second electromagnetic coil, and the changeover switch is stepped by switching the terminals of the second electromagnetic coil. The second electromagnet may be de-energized. The influence of electromagnetic induction that can be generated by turning off the second electromagnet can be avoided.

  (5) The first electromagnet is formed by arranging a plurality of unit electromagnets, and the second electromagnet is formed by a third electromagnetic coil wound so as to surround a plurality of the unit electromagnets. It is also good. It can be selected by the space of the electromagnet.

  (6) The third electromagnetic coil has a third terminal in the middle of the third electromagnetic coil in addition to the terminals at both ends, and the changeover switch is stepwise by switching the terminals of the third electromagnetic coil The energization of the second electromagnet can also be turned off. As mentioned above, the second electromagnet can be turned off stepwise.

  (7) Further, according to the vapor deposition method of the second embodiment of the present invention, the electromagnet, the deposition target substrate, and the vapor deposition mask having a magnetic material are superposed, and the current is supplied to the electromagnet from the power supply circuit. Including a step of adsorbing the deposition substrate and the deposition mask, and depositing the deposition material on the deposition substrate by scattering of the deposition material from a deposition source disposed apart from the deposition mask. The electromagnet comprises a first electromagnet generating a magnetic field in a first direction, and a second electromagnet generating a magnetic field in a direction opposite to the first direction, wherein the first and second electromagnets are simultaneously operated. Switching off the second electromagnet after energization of the second electromagnet.

  According to the vapor deposition method of the second embodiment of the present invention, the first electromagnet and the second electromagnet operate at the same time when the current is applied to the electromagnet, so the magnetic field becomes weak and the influence of the electromagnetic induction is suppressed. Be done. On the other hand, since the second electromagnet is turned off after the current is applied, the magnetic field of the first electromagnet is provided as it is, and the necessary adsorption force can be obtained. As a result, while the adsorption of the deposition substrate and the deposition mask is sufficiently performed, the deterioration of the characteristics of the element or the organic layer can be suppressed.

  (8) When the second electromagnet is turned off, the generation of reverse electromagnetic induction when the second electromagnet is turned off can also be suppressed by switching off stepwise.

  (9) After the deposition of the vapor deposition material is completed, the second electromagnet may be operated and then the current to the electromagnet may be turned off, so that the generation of electromagnetic induction when the current is turned off may also be suppressed. .

  (10) Further, in the method of manufacturing the organic EL display device according to the third embodiment of the present invention, at least the TFT and the first electrode are formed on the support substrate, and the above (7) to (9) are formed on the support substrate. Forming a laminated film of the organic layer by vapor-depositing the organic material using any of the vapor deposition methods of the above, and forming a second electrode on the laminated film.

  According to the method of manufacturing the organic EL display device of the third embodiment of the present invention, when the organic EL display device is manufactured, the characteristics of the element and the organic layer formed on the support substrate are not deteriorated, and thus delicate Pattern display screen is obtained.

DESCRIPTION OF SYMBOLS 1 vapor deposition mask 2 vapor deposition board | substrate 3 electromagnet 3A 1st electromagnet 3B 2nd electromagnet 4 touch plate 5 vapor deposition source 6 power supply circuit 11 resin film 11a opening 12 metal support layer 12a opening 14 frame 15 mask holder 21 support substrate 22 1st Electrode 23 Insulating bank 25 Multilayer film 26 Second electrode 27 Protective film 29 Substrate holder 31 Core (core)
32 Electromagnetic coil (first electromagnetic coil)
33 resin 35 second electromagnetic coil 35a, 35b, 35c terminal 36 cylinder 38 third electromagnetic coil 38a, 38b, 38c terminal 41 support frame 51 vapor deposition material 60 main switch 61 changeover switch

Claims (6)

An electromagnet having a first electromagnet and a second electromagnet generating a magnetic field opposite to the direction of the magnetic field generated by the first electromagnet;
A substrate holder which is provided at a position facing one magnetic pole of the electromagnet and holds a deposition substrate;
A deposition mask provided at a position facing the opposite surface of the deposition target substrate held by the substrate holder to the electromagnet and having a magnetic material;
A deposition source provided opposite to the deposition mask to vaporize or sublime the deposition material;
A power supply circuit for driving the electromagnet;
Equipped with
A deposition apparatus, wherein the electromagnet comprises a cooling device.   In the cooling device, at least one of the first electromagnet and the second electromagnet is formed by a plurality of unit electromagnets, the plurality of unit electromagnets are fixed by a resin, and the inside of the resin is fixed. The vapor deposition apparatus according to claim 1, wherein a water cooling tube is embedded.   The vapor deposition apparatus according to claim 2, wherein the resin is at least one of silicone rubber, silicone resin, and epoxy resin.   The vapor deposition apparatus according to any one of claims 1 to 3, wherein the cooling device is formed by subjecting the surface of the electromagnet to a blackening treatment.   The vapor deposition apparatus according to any one of claims 1 to 4, wherein the cooling device is formed by setting the surface roughness Ra of the electromagnet to 10 μm or more. Forming at least a TFT and a first electrode on a supporting substrate;
A laminated film of organic layers is formed on the support substrate by vapor-depositing an organic material using the vapor deposition apparatus according to any one of claims 1 to 5 ,
A method of manufacturing an organic EL display device, comprising: forming a second electrode on the laminated film.

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