JP7262212B2 - Film forming apparatus, film forming method, and method for manufacturing electronic device - Google Patents

Description

The present invention relates to a film forming apparatus, a film forming method, and a method of manufacturing an electronic device.

Recently, an organic EL display device has been spotlighted as a flat panel display device. Organic EL display devices are self-luminous displays, and are superior to liquid crystal panel displays in characteristics such as response speed, viewing angle, and thinness. It is replacing the display at a fast speed. In addition, the field of application is expanding to automobile displays and the like.

An element of an organic EL display device has a basic structure in which an organic material layer that emits light is formed between two facing electrodes (a cathode electrode and an anode electrode). The organic layer and metal electrode layer of the organic EL display element are formed on the substrate through a mask with a pixel pattern formed by heating an evaporation source containing an evaporation material in a vacuum chamber to evaporate the evaporation material. It is manufactured by

In particular, an evaporation source 700 for depositing a metal electrode layer on a substrate has a plurality of crucibles 710 to 770 arranged on a circumference as shown in FIG. A crucible 710 used for the film is rotated to the deposition position to evaporate the deposition material onto the substrate. Such a rotating multi-point evaporation source is also called a revolver. On the other hand, as the size of substrates on which films are to be formed increases, it becomes necessary to arrange a plurality of evaporation sources in a film forming apparatus in order to increase the film forming speed.

However, when a plurality of evaporation sources are arranged in this way, there is a possibility that the evaporation characteristics of each evaporation source with respect to the substrate may differ depending on the arrangement of the evaporation sources. Although there is a risk, no technique has been proposed for effectively arranging a plurality of evaporation sources in full consideration of the difference in evaporation characteristics of the evaporation sources and the space utilization efficiency in the film forming apparatus.

In consideration of the above points, the present invention provides a film forming apparatus in which a plurality of evaporation sources are effectively arranged so as to improve space utilization efficiency in the film forming apparatus and suppress an increase in the size of the film forming apparatus. An object of the present invention is to provide a film forming method using a film apparatus and a method of manufacturing an electronic device.

In addition, the present invention provides a film forming apparatus capable of improving the efficiency of space utilization in the film forming apparatus, achieving good film formation on a substrate, and reducing the influence of fluctuations in thermal radiation from each evaporation source on the substrate. Another object of the present invention is to provide a film forming method using the apparatus and a method of manufacturing an electronic device.

A film forming apparatus according to a first aspect of the present invention is a film forming apparatus that evaporates and deposits a vapor deposition material on a film forming surface of a rotating substrate, and is arranged in a plane facing the film forming surface of the substrate. three or more evaporation sources, each of the three or more evaporation sources having a plurality of crucibles radially arranged around a rotation axis, rotatable around the rotation axis, The three or more evaporation sources are arranged such that rotation centers of any three of the three or more evaporation sources form a triangular shape in the plane, and Each of the plurality of crucibles includes a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position, and each of the vapor deposition crucibles of the three or more evaporation sources are arranged at the same distance from the central axis of rotation of the substrate, and the centers of rotation of the three or more evaporation sources are arranged on the same circle centered on the central axis of rotation of the substrate in the plane. the vapor deposition crucibles of each of the three or more evaporation sources are arranged inside the circle, and the preheating crucibles of each of the three or more evaporation sources are located closer to the radius of rotation of the substrate. and outside the circle .

A film forming apparatus according to a second aspect of the present invention is a film forming apparatus that evaporates and deposits a vapor deposition material on a film forming surface of a rotating substrate, and is arranged in a plane facing the film forming surface of the substrate. comprising a plurality of evaporation sources, each of the plurality of evaporation sources having a plurality of crucibles radially arranged around a rotation axis, rotatable around the rotation axis, and the plurality of evaporation sources includes a plurality of first evaporation sources having a plurality of first crucibles, and a second evaporation source having a smaller number of second crucibles than the number of the plurality of first crucibles possessed by each of the first evaporation sources , the plurality of first evaporation sources are each arranged on a first circle centered on the rotation center axis of the substrate in the plane, and
The second evaporation source is arranged between two adjacent first evaporation sources among the plurality of first evaporation sources, and the center of rotation of the second evaporation source is the two adjacent first evaporation sources. outside the line segment connecting the rotation centers of the two adjacent first evaporation sources with respect to the rotation center axis of the substrate so as not to be on the same straight line as the line segment connecting the rotation centers of the first circle are also arranged inside .
A film forming apparatus according to a third aspect of the present invention is a film forming apparatus that evaporates and deposits a vapor deposition material on a film forming surface of a rotating substrate, and is arranged in a plane facing the film forming surface of the substrate. comprising a plurality of evaporation sources, each of the plurality of evaporation sources having a plurality of crucibles radially arranged around a rotation axis, rotatable around the rotation axis, and the plurality of evaporation sources includes a plurality of first evaporation sources having a plurality of first crucibles, and a second evaporation source having a smaller number of second crucibles than the number of the plurality of first crucibles possessed by each of the first evaporation sources , the plurality of first evaporation sources are arranged on a first circle centered on the rotation center axis of the substrate in the plane, and the second evaporation sources are arranged on the plurality of first evaporation sources. and the rotation center of the second evaporation source is not located on the same straight line as the line segment connecting the rotation centers of the two adjacent first evaporation sources and the first crucible of each first evaporation source and the second crucible of the second evaporation source are respectively a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position. wherein, in each of the first evaporation source and the second evaporation source, each of the vapor deposition crucibles is arranged at a position closer to the rotation center axis of the substrate than each of the preheating crucibles, and the second The deposition crucible of the evaporation source is arranged inside the rotation center of the second evaporation source with respect to the rotation center axis of the substrate.
A film forming apparatus according to a fourth aspect of the present invention is a film forming apparatus that evaporates and deposits a vapor deposition material on a film forming surface of a rotating substrate, and is arranged in a plane facing the film forming surface of the substrate. comprising a plurality of evaporation sources, each of the plurality of evaporation sources having a plurality of crucibles radially arranged around a rotation axis, rotatable around the rotation axis, and the plurality of evaporation sources includes a plurality of first evaporation sources having a plurality of first crucibles, and a second evaporation source having a smaller number of second crucibles than the number of the plurality of first crucibles possessed by each of the first evaporation sources , the plurality of first evaporation sources are arranged on a first circle centered on the rotation center axis of the substrate in the plane, and the second evaporation sources are arranged on the plurality of first evaporation sources. and the rotation center of the second evaporation source is not located on the same straight line as the line segment connecting the rotation centers of the two adjacent first evaporation sources and the first crucible of each first evaporation source and the second crucible of the second evaporation source are respectively a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position. wherein, in each of the first evaporation source and the second evaporation source, each of the vapor deposition crucibles is arranged at a position closer to the rotation center axis of the substrate than each of the preheating crucibles, and the second The preheating crucible of the evaporation source is arranged outside the center of rotation of the second evaporation source with respect to the central axis of rotation of the substrate.
A film forming apparatus according to a fifth aspect of the present invention is a film forming apparatus that evaporates and deposits a vapor deposition material on a film forming surface of a rotating substrate, and is arranged in a plane facing the film forming surface of the substrate. comprising a plurality of evaporation sources, each of the plurality of evaporation sources having a plurality of crucibles radially arranged around a rotation axis, rotatable around the rotation axis, and the plurality of evaporation sources includes a plurality of first evaporation sources having a plurality of first crucibles, and a second evaporation source having a smaller number of second crucibles than the number of the plurality of first crucibles possessed by each of the first evaporation sources , the plurality of first evaporation sources are arranged on a first circle centered on the rotation center axis of the substrate in the plane, and the second evaporation sources are arranged on the plurality of first evaporation sources. and the rotation center of the second evaporation source is not located on the same straight line as the line segment connecting the rotation centers of the two adjacent first evaporation sources and the first crucible of each first evaporation source and the second crucible of the second evaporation source are respectively a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position. wherein, in each of the first evaporation source and the second evaporation source, each of the vapor deposition crucibles is arranged at a position closer to the rotation center axis of the substrate than each of the preheating crucibles; 1 each of the vapor deposition crucibles of the vapor source and the
The crucible for vapor deposition of two evaporation sources is characterized in that it is arranged outside the radius of rotation of the substrate.
A film forming apparatus according to a sixth aspect of the present invention is a film forming apparatus that evaporates and deposits a vapor deposition material on a film forming surface of a rotating substrate, and is arranged in a plane facing the film forming surface of the substrate. comprising a plurality of evaporation sources, each of the plurality of evaporation sources having a plurality of crucibles radially arranged around a rotation axis, rotatable around the rotation axis, and the plurality of evaporation sources includes a plurality of first evaporation sources having a plurality of first crucibles, and a second evaporation source having a smaller number of second crucibles than the number of the plurality of first crucibles possessed by each of the first evaporation sources , the plurality of first evaporation sources are arranged on a first circle centered on the rotation center axis of the substrate in the plane, and the second evaporation sources are arranged on the plurality of first evaporation sources. and the rotation center of the second evaporation source is not located on the same straight line as the line segment connecting the rotation centers of the two adjacent first evaporation sources and the first crucible of each first evaporation source and the second crucible of the second evaporation source are respectively a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position. wherein, in each of the first evaporation source and the second evaporation source, each of the vapor deposition crucibles is arranged at a position closer to the rotation center axis of the substrate than each of the preheating crucibles; Each of the preheating crucibles of one evaporation source and the preheating crucible of the second evaporation source are arranged outside a radius of rotation of the substrate.
A film forming apparatus according to a seventh aspect of the present invention is a film forming apparatus that evaporates and deposits a vapor deposition material on a film forming surface of a rotating substrate, and is arranged in a plane facing the film forming surface of the substrate. comprising a plurality of evaporation sources, each of the plurality of evaporation sources having a plurality of crucibles radially arranged around a rotation axis, rotatable around the rotation axis, and the plurality of evaporation sources includes a plurality of first evaporation sources having a plurality of first crucibles, and a second evaporation source having a smaller number of second crucibles than the number of the plurality of first crucibles possessed by each of the first evaporation sources , the plurality of first evaporation sources are arranged on a first circle centered on the rotation center axis of the substrate in the plane, and the second evaporation sources are arranged on the plurality of first evaporation sources. and the rotation center of the second evaporation source is not located on the same straight line as the line segment connecting the rotation centers of the two adjacent first evaporation sources and the first crucible of each first evaporation source and the second crucible of the second evaporation source are respectively a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position. and in each of the first evaporation source and the second evaporation source, each of the vapor deposition crucibles is arranged at a position closer to the rotation center axis of the substrate than each of the preheating crucibles, and the film formation The apparatus is a polygonal film forming apparatus having four corners, and when viewed from above, the plurality of first evaporation sources has four corners corresponding to the respective corners of the polygonal film forming apparatus. 1 evaporation sources are arranged at positions corresponding to four corners of a rectangular shape, the vapor deposition crucibles of the first evaporation sources are arranged at positions corresponding to the four corners of the rectangular shape, and the second When viewed from above, the evaporation sources are arranged between two adjacent first evaporation sources among the four first evaporation sources arranged in the rectangular shape, and are arranged along the long side of the rectangular shape. It is characterized by being arranged.

According to the present invention, it is possible to improve the space utilization efficiency in the film forming apparatus and suppress the enlargement of the film forming apparatus. The influence on the substrate can be effectively reduced.

FIG. 1 is a schematic diagram of part of an electronic device manufacturing apparatus. FIG. 2 is a schematic diagram of a film forming apparatus according to an embodiment of the present invention. FIG. 3 is a top view for explaining the positional relationship between a substrate and a plurality of evaporation sources in a film forming apparatus according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing the positional relationship of the vapor deposition crucible and the preheating crucible of each evaporation source relative to the substrate in the film forming apparatus according to an embodiment of the present invention. FIG. 5 is a top view for explaining the positional relationship between a substrate and a plurality of evaporation sources in a film forming apparatus according to another embodiment of the present invention. FIG. 6 is a schematic diagram of an organic EL device of the present invention. FIG. 7 is a schematic diagram of a rotating multi-point evaporation source (revolver).

Preferred embodiments and examples of the present invention will now be described with reference to the drawings. However, the following embodiments and examples exemplify preferred configurations of the present invention, and the scope of the present invention is not limited to these configurations. In addition, in the following description, the scope of the present invention is limited to the hardware configuration and software configuration of the device, process flow, manufacturing conditions, size, material, shape, etc., unless otherwise specified. It is not the intention to do so.

<Electronic Device Manufacturing Equipment>
FIG. 1 is a schematic diagram showing an example of an electronic device manufacturing apparatus.
The electronic device manufacturing apparatus of FIG. 1 is used, for example, for manufacturing display panels of organic EL display devices for smartphones. In the case of a display panel for smartphones, for example, a full-size (about 1500 mm × about 1850 mm) or half-cut size (about 1500 mm × about 925 mm) substrate is subjected to film formation for forming an organic EL display element, and then the Cut out the substrate to produce multiple small size panels.

As shown in FIG. 1, an electronic device manufacturing apparatus generally includes a plurality of cluster apparatuses 1. Each cluster apparatus 1 includes a plurality of film formation chambers 11 in which processing (for example, film formation) is performed on a substrate 10. , a plurality of mask stock chambers 12 in which masks before and after use are stored, and a transfer chamber 13 arranged in the center thereof.

A transfer robot 14 is installed in the transfer chamber 13 to transfer the substrate 10 between the film formation chambers 11 and transfer the mask between the film formation chambers 11 and the mask stock chamber 12 . The transport robot 14 is, for example, a robot having a structure in which a robot hand holding the substrate 10 is attached to an articulated arm.

Each film forming chamber 11 is provided with a film forming apparatus (also referred to as a vapor deposition apparatus). In the film forming apparatus, the vapor deposition material stored in the evaporation source is heated by the heater to evaporate, and is vapor deposited on the substrate 10 through the mask. A series of film formation processes, such as transfer of the substrate 10 to and from the transport robot 14, adjustment of the relative positions of the substrate 10 and the mask (alignment), fixing of the substrate 10 onto the mask, and film formation (evaporation), are performed by the film formation apparatus. done automatically.

In the mask stock chamber 12, a new mask to be used in the film forming process in the film forming chamber 11 and a used mask are stored separately in two cassettes. The transport robot 14 transports the used mask from the film formation chamber 11 to a cassette in the mask stock chamber 12 and transports a new mask stored in another cassette in the mask stock chamber 12 to the film formation chamber 11 .

The cluster device 1 includes a pass chamber 15 for transferring the substrates 10 from the upstream side to the cluster device 1 in the flow direction of the substrates 10, and a pass chamber 15 for transferring the substrates 10 that have undergone the film forming process in the cluster device 1 to the other downstream side. A buffer chamber 16 for transmitting to the cluster device 1 is connected. The transfer robot 14 in the transfer chamber 13 receives the substrate 10 from the pass chamber 15 on the upstream side and transfers it to one of the film formation chambers 11 (for example, the film formation chamber 11a) in the cluster device 1 . Further, the transport robot 14 receives the substrate 10 on which the film forming process in the cluster apparatus 1 has been completed from one of the plurality of film forming chambers 11 (for example, the film forming chamber 11b), and transfers the substrate to the buffer connected downstream. Transfer to chamber 16 .

Between the buffer chamber 16 and the pass chamber 15, a swirling chamber 17 for changing the orientation of the substrate is installed. As a result, the direction of the substrate 10 becomes the same between the cluster device 1 on the upstream side and the cluster device 1 on the downstream side, which facilitates substrate processing.

In this example, the configuration of the electronic device manufacturing apparatus was described with reference to FIG. may change.

The configuration of the film forming apparatus provided in the film forming chamber 11 will be described below.
<Deposition equipment>
FIG. 2 is a cross-sectional view schematically showing the configuration of a film forming apparatus, in particular, a film forming apparatus 2 for a metallic deposition material used to form a metal electrode layer.

The film forming apparatus 2 has a vacuum chamber 20 . The inside of the vacuum chamber 20 is maintained in a reduced-pressure atmosphere such as vacuum or an inert gas atmosphere such as nitrogen gas. A substrate holding unit 21 and a mask table 22 are installed in the upper part inside the vacuum chamber 20 , and an evaporation source 23 is installed in the lower part inside the vacuum chamber 20 .
The substrate holding unit 21 is means for holding and transferring the substrate 10 received from the transfer robot 14 in the transfer chamber 13, and is also called a substrate holder.
A frame-shaped mask table 22 is installed below the substrate holding unit 21 , and a mask 222 is placed on the mask table 22 . Mask 222 has an opening pattern corresponding to the thin film pattern to be formed on substrate 10 .

During film formation, the substrate holding unit 21 is lowered relative to the mask table 22 (or the mask table 22 is raised toward the substrate holding unit 21 ), and the substrate 10 held by the substrate holding unit 21 is moved to the mask 222 . After being placed on the mask 222 and the substrate placed on the mask 222 , the substrate holding unit 21 and the mask table 22 are rotated by the rotating shaft 27 introduced from the upper part (outside) of the vacuum chamber 20 . Rotate 10. This is for the purpose of forming a film of a metallic vapor deposition material on the substrate 10 with a uniform thickness.

Although not shown in FIG. 2 , a drive mechanism including an actuator for rotating the rotating shaft 27 is installed outside the upper surface of the vacuum chamber 20 (atmosphere side). A substrate shutter (not shown) can be provided below the mask table 22 . The substrate shutter covers the substrate 10 except during film formation on the substrate 10 , and prevents the evaporation material evaporated from the evaporation source 23 from depositing on the substrate 10 .

In the lower part of the interior of the vacuum chamber 20, an evaporation source 23 including a crucible 231 containing a vapor deposition material to be deposited on the substrate 10 and a heater (not shown) for heating the crucible 231, an evaporation source shutter 25, An evaporation rate sensor 26 or the like is installed.

A plurality of evaporation sources 23 of the film forming apparatus 2 for metallic evaporation material are installed on the bottom surface of the vacuum chamber, and each evaporation source 23 includes a plurality of crucibles 231 . Each evaporation source 23 is rotated by a rotary drive mechanism (not shown) to sequentially move the positions of the plurality of crucibles 231, and the evaporation material is removed from the crucibles that have been moved to predetermined evaporation positions by this positional movement of the crucibles. It is a rotating multi-point evaporation source (revolver) that sequentially evaporates and deposits on the substrate 10 .
A detailed structure of each evaporation source 23 and an arrangement configuration of the plurality of evaporation sources 23 will be described later.

An evaporation source shutter 25 may be installed above the evaporation source 23 in order to block or open the movement path of the vapor deposition material to the substrate 10 . As a result, the deposition of the vapor deposition material evaporated from the crucible at the vapor deposition position on the substrate 10 is temporarily suppressed as necessary (for example, in the preparatory process before starting film formation). By rotating the evaporation source shutter 25 to open the top of the crucible at the evaporation position, the evaporation material from the crucible at the evaporation position scatters toward the substrate 10, and film formation on the substrate 10 is started.
The evaporation rate sensor 26 is a device that monitors the rate at which the evaporation material is evaporated from the crucible 231 of the evaporation source 23 . The details of the arrangement position of the evaporation rate sensor 26 will be described later.

<Placement of Evaporation Source>
The structure of a rotating multi-point evaporation source (revolver) and the arrangement configuration of a plurality of evaporation sources according to an embodiment of the present invention will be described with reference to FIG.
FIG. 3 is a top view for explaining the positional relationship between the substrate 10 and the plurality of evaporation sources 23 in the film forming apparatus 2. As shown in FIG.

As described above, the substrate 10 that is rotated by being driven by the rotary shaft 27 during film formation is placed in the upper part of the vacuum chamber of the film formation apparatus 2 . A plurality of (three or more) evaporation sources 23 are arranged in the lower part of the vacuum chamber of the film forming apparatus 2 so as to face the substrate 10 in the plane facing the film forming surface of the substrate 10 . In this embodiment, when viewed from the top of the film forming apparatus 2 (planar view), the four evaporation sources 23 are arranged at four corners of a rectangular shape D1 corresponding to the respective corners of the polygonal film forming apparatus 2. is placed at a position corresponding to

As described above, each evaporation source 23 is a rotary multi-point evaporation source (revolver) that sequentially moves the positions of a plurality of crucibles 231 by rotation (rotation) during film formation and evaporates the evaporation material for each crucible. and has a plurality of crucibles 231 radially arranged around their respective rotation axes. On the other hand, as shown in the figure, the four evaporation sources 23 rotate (rotate) in mutually opposite directions, and sequentially move the respective crucibles to form films. The rotation direction of each evaporation source 23 is not particularly limited to this.

The number of crucibles 231 installed in each evaporation source 23 is not particularly limited, and the number of crucibles in each evaporation source 23 may be the same or different. This embodiment shows an example in which each evaporation source 23 has seven crucibles 231 .

One crucible 232 out of seven crucibles 231 in each evaporation source 23 is positioned at the evaporation position during film formation. The vapor deposition position is a position where the crucible located at the position evaporates and supplies the vapor deposition material toward the substrate 10 . That is, each evaporation source 23 heats a crucible 232 positioned at the evaporation position (hereinafter also referred to as a “vapor deposition crucible”) to a high temperature (for example, 1300° C.) by a heater and accommodates it in the corresponding crucible 232 at the time of film formation. The evaporated deposition material is evaporated and deposited on the substrate 10 .

When the deposition material in the crucible 232 at the deposition position is exhausted, the evaporation source 23 is rotated to move the crucible 232 located at the deposition position to the post-deposition position, and the crucible 233 located at the preheating position is moved to the deposition position 232 . rotate to

A preheat position is a position where the next time (eg, when the deposition material in the crucible 232 at the deposition position is exhausted) the crucible that is moved to the deposition position is preheated. Hereinafter, the crucible 233 positioned at the preheating position is also referred to as "preheating crucible". In this way, by preheating the crucible 233 that is to be moved to the vapor deposition position next time, it is possible to reduce the time required to heat the crucible 233 that is positioned at the preheating position after it is moved to the vapor deposition position. The film formation time can be shortened.

The vapor deposition position and the preheating position are spaced apart so that the crucibles placed at these positions are not affected by thermal interference with each other. In this embodiment, another crucible is arranged between the vapor deposition crucible 232 and the preheating crucible 233 .

Evaporation is performed while rotating the evaporation source 23 until the evaporation material in all the crucibles 231 of each evaporation source 23 is exhausted. Fill with vapor deposition material.

A structure in which a plurality of evaporation sources 23 are arranged in the film forming apparatus 2 will be described in detail below.
As shown in FIG. 3, a plurality of (four in this embodiment) evaporation sources 23 are arranged such that the rotation centers of any three evaporation sources 23 are not aligned on the same straight line. In other words, if the distances between the rotation center axes of the three arbitrarily selected evaporation sources 23 are a, b, and c, then the relationship a+b>c is satisfied (that is, a triangular shape is formed). A plurality of evaporation sources 23 are arranged. More specifically, the plurality of evaporation sources 23 are arranged so that the rotation center of each evaporation source 23 is positioned on one concentric circle C1 centered on the rotation center axis O of the substrate 10 within the arrangement plane of the evaporation sources 23. placed.

Therefore, since none of the three evaporation sources 23 among the plurality of evaporation sources 23 are positioned on a straight line, the plurality of evaporation sources 23 can be arranged in the film forming apparatus 2 without increasing the distance between the evaporation sources 23 . It can be arranged effectively, and the space utilization efficiency in the film forming apparatus 2 can be improved.

Further, under such arrangement of the plurality of evaporation sources 23 , the evaporation crucible 232 of each evaporation source 23 is arranged inside the circle C<b>1 connecting the rotation centers of the evaporation sources 23 . More specifically,
The crucible 232 for vapor deposition of each evaporation source 23 is positioned on a concentric circle C2 inside a circle C1 connecting the rotation centers of the evaporation sources 23 and having substantially the same distance from the rotation center axis O of the substrate 10. are arranged to
In this way, in the plurality of evaporation sources 23, the evaporation crucibles 232 that actually supply the evaporation material during film formation are positioned at substantially the same distance from the substrate 10, so that the evaporation characteristics between the evaporation sources 23 are difference can be suppressed.

Further, under the arrangement of the plurality of evaporation sources 23 as described above, the preheating crucible 233 of each evaporation source 23 is arranged outside the circle C1 connecting the rotation centers of the evaporation sources 23 . In other words, the placement relationship of the plurality of crucibles 231 in each evaporation source 23 is configured so that the vapor deposition crucible 232 is located at a short distance from the center of the substrate 10 and the preheating crucible 233 is located at a farther distance. there is FIG. 4 is a cross-sectional view schematically showing the relative arrangement relationship of the deposition crucible 232 and the preheating crucible 233 in each evaporation source 23 with respect to the substrate 10 . More specifically, each preheating crucible 233 of the evaporation source 23 is arranged to be positioned outside the radius of rotation of the substrate 10 . That is, the preheating crucible 233 of any evaporation source 23 is arranged at a position not overlapping the substrate 10 .

The preheating crucible 233 does not substantially participate in vapor deposition during film formation, but is maintained at a high temperature necessary for preheating, so the heat radiated from the crucible may affect the substrate 10 . be. When a plurality of evaporation sources 23 are arranged below the substrate 10 , the heat radiated from the preheating crucible 233 may affect the substrate 10 differently in each evaporation source 23 .
In the embodiment of the present invention, each evaporation source 23 is provided with a preheating crucible 233 that does not substantially participate in evaporation during film formation so as to be positioned outside the radius of rotation of the substrate 10 . The influence of variations in thermal radiation from the substrate 10 on the substrate 10 can be reduced.

As described above with reference to FIG. 2, in the region between the film formation surface of the substrate 10 and the plurality of evaporation sources 23, the rate of evaporation material evaporated from the evaporation crucibles 232 of each evaporation source 23 is monitored. An evaporation rate sensor 26 can be installed for The evaporation rate sensor 26 should be placed above the evaporation source 23 outside the circle C1 connecting the rotation centers of the evaporation source 23 so as not to affect the film formation on the substrate 10 during film formation. is preferred.

As described above, according to this embodiment, it is possible to improve the space utilization efficiency in the film forming apparatus and suppress the enlargement of the apparatus. The influence of variations on the substrate 10 can be reduced.

FIG. 5 shows an arrangement of a rotating multi-point evaporation source (revolver) according to another embodiment of the present invention.
In addition to the configuration of the above embodiment, the present embodiment has a configuration in which a small-diameter evaporation source 24 having a small number of crucibles 241 is additionally arranged. Evaporation source 24 has a smaller diameter than evaporation source 23 . Specifically, as shown in FIG. 5 , a small-diameter evaporation source 24 in which five crucibles 241 are arranged radially around a rotation axis (rotational axis) is placed between two adjacent large-diameter evaporation sources 23 . are placed in

In some cases, large-diameter evaporation sources 23 and small-diameter evaporation sources 24 having different numbers of crucibles are arranged together in the film forming apparatus 2 in order to control the type of vapor deposition material, the amount of evaporation, etc. .
Even in this case, as in the previous embodiment, the present embodiment is an evaporation source that can improve the efficiency of space utilization in the film forming apparatus, achieve good film formation, and suppress variations in heat radiation from each evaporation source. We propose the configuration of

Specifically, the large-diameter evaporation sources 23 (hereinafter referred to as "first evaporation sources") are four evaporation sources corresponding to the corners of the polygonal film forming apparatus 2, as in the above-described embodiment. The sources 23 are arranged at positions corresponding to the four corners of the rectangular shape so that the rotation center of the source 23 is positioned on one concentric circle C1 around the rotation center axis O of the substrate 10 . As shown in FIG. 5, each vapor deposition crucible 232 of the first evaporation source 23 is arranged at positions corresponding to four corners of the rectangular shape D2. Also, as shown in FIG. 5, the evaporation source 24 is arranged between two adjacent first evaporation sources 23 along the long side of the rectangular shape D2.

In addition, in each first evaporation source 23, the vapor deposition crucible 232 is located inside the circle C1 connecting the rotation centers of the first evaporation sources 23 and is substantially the same distance from the rotation center axis O of the substrate 10. are arranged so as to be positioned on the circle C2 of . In the example shown in FIG. 5 , in each first evaporation source 23 , the preheating crucible 233 is positioned outside the circle C1 connecting the rotation centers of the evaporation sources 23 , more specifically, outside the radius of rotation of the substrate 10 . It is arranged so as to be located on the outside.

The small-diameter evaporation source 24 (hereinafter referred to as “second evaporation source”) is positioned between two adjacent first evaporation sources 23 , specifically two first evaporation sources where the rotation centers of the second evaporation sources 24 are adjacent. It is arranged so as not to be on the same straight line as the line segment L connecting the rotation center of the source 23 . More specifically, the second evaporation source 24 is arranged so that its center of rotation is positioned outside the line segment L and inside the circle C1 with respect to the rotation center axis O of the substrate 10 .

Therefore, it is possible to narrow the distance between the two first evaporation sources 23 adjacent to each other with the second evaporation source 24 interposed therebetween. , the efficiency of space utilization inside the film forming apparatus 2 can be further enhanced. Note that, as shown in FIG. 5 , the number of crucibles 241 in the second evaporation source 24 is smaller than the number of crucibles 231 in the first evaporation source 23 .

Also, the vapor deposition crucible 242 and the preheating crucible 243 in the second evaporation source 24 can be arranged in the same manner as in the first evaporation source 23 .
That is, in the second evaporation source 24 , the vapor deposition crucible 242 is arranged closer to the rotation center axis O of the substrate 10 than the preheating crucible 243 . Specifically, the vapor deposition crucible 242 is arranged inside the rotation center of the second evaporation source 24 , and the preheating crucible 243 is arranged outside the rotation center of the second evaporation source 24 .

Furthermore, in locating the second evaporation source 24 inside the film forming apparatus 2 as much as possible, the arrangement condition of the evaporation crucible 242 and the preheating crucible 243 of the second evaporation source 24 and the adjacent first evaporation Considering the positional relationship with the source 23, they are arranged as follows.
That is, the second evaporation source 24 is arranged so that the evaporation crucible 242 is located at the same distance from the rotation center axis O of the substrate 10 as the evaporation crucibles 232 of the first evaporation source 23 (on the circle C2). ), and at the same time, the preheating crucible 243 is positioned outside the radius of rotation of the substrate 10 like the preheating crucibles 233 of the first evaporation source 23. is preferred.
As a result, it is possible to improve the efficiency of space utilization in the film forming apparatus, and to reduce the effects on the substrate 10 caused by fluctuations in the heat radiation from the evaporation source (particularly, the crucible for preheating).

<Method for manufacturing electronic device>
Next, an example of an electronic device manufacturing method using the film forming apparatus according to the above-described embodiment will be described. The configuration and manufacturing method of an organic EL display device will be exemplified below as an example of an electronic device.

First, the organic EL display device to be manufactured will be described. FIG. 6(a) shows an overall view of the organic EL display device 50, and FIG. 6(b) shows a cross-sectional structure of one pixel.

As shown in FIG. 6A, in a display region 51 of an organic EL display device 50, a plurality of pixels 52 each having a plurality of light emitting elements are arranged in a matrix. Although details will be described later, each of the light emitting elements has a structure including an organic layer sandwiched between a pair of electrodes. The term "pixel" as used herein refers to a minimum unit capable of displaying a desired color in the display area 51. FIG. In the case of the organic EL display device 50 according to this embodiment, the pixel 52 is configured by a combination of the first light emitting element 52R, the second light emitting element 52G, and the third light emitting element 52B that emit light different from each other. The pixel 52 is often composed of a combination of a red light emitting element, a green light emitting element and a blue light emitting element, but may be a combination of a yellow light emitting element, a cyan light emitting element and a white light emitting element. It is not limited.

FIG. 6(b) is a schematic partial cross-sectional view taken along line AB in FIG. 6(a). The pixel 52 includes, on a substrate 53, a first electrode (anode) 54, a hole transport layer 55, one of the light emitting layers 56R, 56G, and 56B, an electron transport layer 57, and a second electrode (cathode) 58. and an organic EL element. Among these layers, the hole transport layer 55, the light emitting layers 56R, 56G and 56B, and the electron transport layer 57 correspond to organic layers. In this embodiment, the light emitting layer 56R is an organic EL layer that emits red, the light emitting layer 56G is an organic EL layer that emits green, and the light emitting layer 56B is an organic EL layer that emits blue. The light-emitting layers 56R, 56G, and 56B are formed in patterns corresponding to light-emitting elements (also referred to as organic EL elements) that emit red, green, and blue, respectively. Also, the first electrode 54 is formed separately for each light emitting element. The hole transport layer 55, the electron transport layer 57, and the second electrode 58 may be formed in common with the plurality of light emitting elements 52R, 52G, and 52B, or may be formed for each light emitting element. An insulating layer 59 is provided between the first electrodes 54 to prevent short-circuiting between the first electrode 54 and the second electrode 58 due to foreign matter. Furthermore, since the organic EL layer is deteriorated by moisture and oxygen, a protective layer 60 is provided to protect the organic EL element from moisture and oxygen.

In order to form the organic EL layer for each light emitting element, a method of film formation through a mask is used. 2. Description of the Related Art In recent years, the resolution of display devices has been increasing, and a mask having an opening width of several tens of μm is used for forming an organic EL layer.

Next, an example of a method for manufacturing an organic EL display device will be specifically described.
First, a substrate 53 on which a circuit (not shown) for driving the organic EL display device and a first electrode 54 are formed is prepared.

An acrylic resin is formed by spin coating on the substrate 53 on which the first electrode 54 is formed, and the acrylic resin is patterned by a lithography method so that an opening is formed in the portion where the first electrode 54 is formed, and insulation is performed. Layer 59 is formed. This opening corresponds to a light emitting region where the light emitting element actually emits light.

A substrate 53 patterned with an insulating layer 59 is carried into a first film forming apparatus, the substrate 53 is held by a substrate holding unit, and a hole transport layer 55 is commonly formed on the first electrodes 54 in the display area. Deposited as a layer. The hole transport layer 55 is deposited by vacuum deposition. Since the hole transport layer 55 is actually formed to have a size larger than that of the display area 51, a high-definition mask is not required.

Next, the substrate 53 formed with up to the hole transport layer 55 is carried into the second film forming apparatus and held by the substrate holding unit. Alignment of the substrate 53 and the mask is performed, the substrate 53 is placed on the mask, and a light-emitting layer 56R emitting red is formed on the portion of the substrate 53 where the element emitting red is to be arranged.

Similarly to the deposition of the light emitting layer 56R, the third deposition apparatus deposits the green light emitting layer 56G, and the fourth deposition apparatus deposits the blue light emitting layer 56B. After the formation of the light-emitting layers 56R, 56G, and 56B is completed, the electron transport layer 57 is formed over the entire display area 51 by the fifth film forming apparatus. The electron transport layer 57 is formed as a layer common to the three color light-emitting layers 56R, 56G, and 56B.

The substrate on which the electron transport layer 57 is formed is moved to a sixth film forming apparatus, the second electrode 58 is formed thereon, and then the protective layer 60 is formed by moving to the plasma CVD apparatus to form an organic EL display. Device 50 is completed.

If the substrate 53 on which the insulating layer 59 is patterned is carried into the film forming apparatus and is exposed to an atmosphere containing moisture and oxygen until the film formation of the protective layer 60 is completed, the light emitting layer made of the organic EL material will be damaged. It may deteriorate due to moisture and oxygen. Therefore, substrates are carried in and out between film forming apparatuses under a vacuum atmosphere or an inert gas atmosphere.

Although the embodiments for carrying out the present invention have been specifically described above, the above-described embodiments are examples of the present invention, and the present invention is not limited to the configurations of these embodiments. can be appropriately deformed within the range of For example, the number of multiple evaporation sources arranged in the film forming apparatus and the number of multiple crucibles provided in each evaporation source (large-diameter evaporation source and/or small-diameter evaporation source) may vary depending on the design. can be changed as appropriate. For example, in the other embodiment described above in which the large-diameter evaporation source 23 and the small-diameter evaporation source 24 are co-located, another small-diameter evaporation source 23 is placed at an opposing position within the deposition apparatus 2, as indicated by the dashed line in FIG. A second evaporation source 24 can also be arranged. Further, in the above-described embodiment, the vapor deposition crucibles of the respective vapor sources are arranged on the circle C2 at the same distance from the center of the substrate 10. In addition to being the same, it also includes giving a slight offset according to design conditions such as the type of vapor deposition material.

1: Cluster device 2: Film formation device 11: Film formation chamber 20: Vacuum chamber 21: Substrate holding unit 22: Mask table 23: First evaporation source (large diameter)
24: Second evaporation source (small diameter)
25: Evaporation source shutter 26: Evaporation rate sensor 231, 241: Crucible 232, 242: Vapor deposition crucible (Vapor deposition position)
233, 243: Preheating crucible (preheating position)
50: Organic EL display device

Claims (21)

A film forming apparatus for evaporating and depositing a deposition material on a film forming surface of a rotating substrate,
including three or more evaporation sources arranged in a plane facing the film formation surface of the substrate;
Each of the three or more evaporation sources has a plurality of crucibles radially arranged around a rotation axis, and is rotatable around the rotation axis;
the three or more evaporation sources are arranged such that the rotation centers of any three of the three or more evaporation sources form a triangular shape in the plane;
the plurality of crucibles for each of the three or more evaporation sources includes a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position;
the vapor deposition crucibles of the three or more evaporation sources are arranged at the same distance from the central axis of rotation of the substrate in the plane ;
the rotation centers of the three or more evaporation sources are arranged on the same circle centered on the rotation center axis of the substrate in the plane;
The vapor deposition crucibles of each of the three or more evaporation sources are arranged inside the circle,
The film forming apparatus, wherein the preheating crucibles of the three or more evaporation sources are arranged outside a radius of rotation of the substrate and outside the circle. The deposition position is a position where the crucible located at the position supplies the deposition material toward the substrate,
2. The film forming apparatus according to claim 1 , wherein the preheating position is a position where the crucible positioned at the preheating position is preheated before being moved to the vapor deposition position by rotation of the evaporation source. A film forming apparatus for evaporating and depositing a deposition material on a film forming surface of a rotating substrate,
including a plurality of evaporation sources arranged in a plane facing the film formation surface of the substrate;
Each of the plurality of evaporation sources has a plurality of crucibles radially arranged around a rotation axis, and is rotatable around the rotation axis,
The plurality of evaporation sources include a plurality of first evaporation sources having a plurality of first crucibles and a second evaporation source having a number of second crucibles less than the number of the plurality of first crucibles possessed by each of the first evaporation sources. an evaporation source;
each of the plurality of first evaporation sources is arranged on a first circle centered on the rotation center axis of the substrate in the plane,
The second evaporation source is arranged between two adjacent first evaporation sources among the plurality of first evaporation sources, and the center of rotation of the second evaporation source is the two adjacent first evaporation sources. outside the line segment connecting the rotation centers of the two adjacent first evaporation sources with respect to the rotation center axis of the substrate so as not to be on the same straight line as the line segment connecting the rotation centers of the first circle and a film forming apparatus, wherein the film forming apparatus is arranged inside . the first crucible of each first evaporation source and the second crucible of the second evaporation source each include a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position;
3. The crucible for vapor deposition in each of the first evaporation source and the second evaporation source is arranged at a position closer to the rotation center axis of the substrate than each of the preheating crucibles. 3. The film forming apparatus according to 3 . 5. The film forming apparatus according to claim 4, wherein each of the vapor deposition crucibles of each of the first evaporation sources is arranged inside the first circle. 6. The film forming apparatus according to claim 4 , wherein the preheating crucibles of the first evaporation sources are arranged outside the first circle. A film forming apparatus for evaporating and depositing a deposition material on a film forming surface of a rotating substrate,
including a plurality of evaporation sources arranged in a plane facing the film formation surface of the substrate;
Each of the plurality of evaporation sources has a plurality of crucibles radially arranged around a rotation axis, and is rotatable around the rotation axis,
The plurality of evaporation sources include a plurality of first evaporation sources having a plurality of first crucibles and a second evaporation source having a number of second crucibles less than the number of the plurality of first crucibles possessed by each of the first evaporation sources. an evaporation source;
each of the plurality of first evaporation sources is arranged on a first circle centered on the rotation center axis of the substrate in the plane,
The second evaporation source is arranged between two adjacent first evaporation sources among the plurality of first evaporation sources, and the center of rotation of the second evaporation source is the two adjacent first evaporation sources. is arranged so as not to be on the same straight line as the line segment connecting the rotation centers of
the first crucible of each first evaporation source and the second crucible of the second evaporation source each include a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position;
In each of the first evaporation source and the second evaporation source, each of the vapor deposition crucibles is arranged closer to the rotation center axis of the substrate than each of the preheating crucibles,
The deposition apparatus, wherein the vapor deposition crucible of the second evaporation source is arranged inside the rotation center of the second evaporation source with respect to the rotation center axis of the substrate. A film forming apparatus for evaporating and depositing a deposition material on a film forming surface of a rotating substrate,
including a plurality of evaporation sources arranged in a plane facing the film formation surface of the substrate;
Each of the plurality of evaporation sources has a plurality of crucibles radially arranged around a rotation axis, and is rotatable around the rotation axis,
The plurality of evaporation sources include a plurality of first evaporation sources having a plurality of first crucibles and a second evaporation source having a number of second crucibles less than the number of the plurality of first crucibles possessed by each of the first evaporation sources. an evaporation source;
In the plurality of first evaporation sources, each rotation center is centered on the rotation center axis of the substrate in the plane.
is placed on the first circle with
The second evaporation source is arranged between two adjacent first evaporation sources among the plurality of first evaporation sources, and the center of rotation of the second evaporation source is the two adjacent first evaporation sources. is arranged so as not to be on the same straight line as the line segment connecting the rotation centers of
the first crucible of each first evaporation source and the second crucible of the second evaporation source each include a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position;
In each of the first evaporation source and the second evaporation source, each of the vapor deposition crucibles is arranged closer to the rotation center axis of the substrate than each of the preheating crucibles,
The film forming apparatus, wherein the preheating crucible of the second evaporation source is arranged outside the center of rotation of the second evaporation source with respect to the central axis of rotation of the substrate. A film forming apparatus for evaporating and depositing a deposition material on a film forming surface of a rotating substrate,
including a plurality of evaporation sources arranged in a plane facing the film formation surface of the substrate;
Each of the plurality of evaporation sources has a plurality of crucibles radially arranged around a rotation axis, and is rotatable around the rotation axis,
The plurality of evaporation sources include a plurality of first evaporation sources having a plurality of first crucibles and a second evaporation source having a number of second crucibles less than the number of the plurality of first crucibles possessed by each of the first evaporation sources. an evaporation source;
each of the plurality of first evaporation sources is arranged on a first circle centered on the rotation center axis of the substrate in the plane,
The second evaporation source is arranged between two adjacent first evaporation sources among the plurality of first evaporation sources, and the center of rotation of the second evaporation source is the two adjacent first evaporation sources. is arranged so as not to be on the same straight line as the line segment connecting the rotation centers of
the first crucible of each first evaporation source and the second crucible of the second evaporation source each include a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position;
In each of the first evaporation source and the second evaporation source, each of the vapor deposition crucibles is arranged closer to the rotation center axis of the substrate than each of the preheating crucibles,
The deposition apparatus, wherein each of the vapor deposition crucibles of the first vapor sources and the vapor deposition crucibles of the second vapor source are arranged outside a radius of rotation of the substrate. A film forming apparatus for evaporating and depositing a deposition material on a film forming surface of a rotating substrate,
including a plurality of evaporation sources arranged in a plane facing the film formation surface of the substrate;
Each of the plurality of evaporation sources has a plurality of crucibles radially arranged around a rotation axis, and is rotatable around the rotation axis,
The plurality of evaporation sources include a plurality of first evaporation sources having a plurality of first crucibles and a second evaporation source having a number of second crucibles less than the number of the plurality of first crucibles possessed by each of the first evaporation sources. an evaporation source;
each of the plurality of first evaporation sources is arranged on a first circle centered on the rotation center axis of the substrate in the plane,
The second evaporation source is arranged between two adjacent first evaporation sources among the plurality of first evaporation sources, and the center of rotation of the second evaporation source is the two adjacent first evaporation sources. is arranged so as not to be on the same straight line as the line segment connecting the rotation centers of
the first crucible of each first evaporation source and the second crucible of the second evaporation source each include a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position;
In each of the first evaporation source and the second evaporation source, each of the vapor deposition crucibles is arranged closer to the rotation center axis of the substrate than each of the preheating crucibles,
The film forming apparatus, wherein each of the preheating crucibles of the first evaporation sources and the preheating crucible of the second evaporation sources are arranged outside a radius of rotation of the substrate. 7 to 10, wherein each of the vapor deposition crucibles of each of the first evaporation sources and the vapor deposition crucible of the second evaporation source are arranged at the same distance from the central axis of rotation of the substrate. 11. The film forming apparatus according to any one of 10. The deposition position is a position where the crucible located at the position supplies the deposition material toward the substrate,
12. The preheating position is a position where the crucible positioned at the preheating position is preheated before being moved to the vapor deposition position by the rotation of each of the evaporation sources. The film forming apparatus according to item 1. The film forming apparatus is a polygonal film forming apparatus having a plurality of corners, and the plurality of first evaporation sources correspond to the respective corners of the polygonal film forming apparatus when viewed from above. 13. The film forming apparatus according to any one of claims 3 to 12 , wherein each of the first evaporation sources is arranged. The film forming apparatus is a film forming apparatus having four corners, and the plurality of first evaporation sources are four first evaporation sources corresponding to the respective corners of the film forming apparatus when viewed from above. 14. The film forming apparatus according to claim 13 , wherein are arranged at positions corresponding to four corners of a rectangular shape. The film forming apparatus is a polygonal film forming apparatus having four corners, and the plurality of first evaporation sources correspond to the respective corners of the polygonal film forming apparatus when viewed from above. Four first evaporation sources are arranged at positions corresponding to four corners of a rectangular shape, and the vapor deposition crucibles of the respective first evaporation sources are arranged at positions corresponding to the four corners of the rectangular shape. 13. The film forming apparatus according to any one of claims 4 to 12 , characterized in that: A film forming apparatus for evaporating and depositing a deposition material on a film forming surface of a rotating substrate,
including a plurality of evaporation sources arranged in a plane facing the film formation surface of the substrate;
Each of the plurality of evaporation sources has a plurality of crucibles radially arranged around a rotation axis, and is rotatable around the rotation axis,
The plurality of evaporation sources include a plurality of first evaporation sources having a plurality of first crucibles and a second evaporation source having a number of second crucibles less than the number of the plurality of first crucibles possessed by each of the first evaporation sources. an evaporation source;
each of the plurality of first evaporation sources is arranged on a first circle centered on the rotation center axis of the substrate in the plane,
The second evaporation source is arranged between two adjacent first evaporation sources among the plurality of first evaporation sources, and the center of rotation of the second evaporation source is the two adjacent first evaporation sources. is arranged so as not to be on the same straight line as the line segment connecting the rotation centers of
the first crucible of each first evaporation source and the second crucible of the second evaporation source each include a vapor deposition crucible positioned at a vapor deposition position and a preheating crucible positioned at a preheating position;
In each of the first evaporation source and the second evaporation source, each of the vapor deposition crucibles is arranged closer to the rotation center axis of the substrate than each of the preheating crucibles,
The film forming apparatus is a polygonal film forming apparatus having four corners, and the plurality of first evaporation sources correspond to the respective corners of the polygonal film forming apparatus when viewed from above. Four first evaporation sources are arranged at positions corresponding to four corners of a rectangular shape, and the respective vapor deposition crucibles of the first evaporation sources are arranged at positions corresponding to the four corners of the rectangular shape,
When viewed from above, the second evaporation source is arranged between two adjacent first evaporation sources among the four first evaporation sources arranged in the rectangular shape, and has a long side of the rectangular shape. A film forming apparatus characterized by being arranged along. 17. The film forming apparatus according to any one of claims 14 to 16 , wherein the four first evaporation sources rotate in directions opposite to each other. Claims 3 to 17 , further comprising an evaporation rate sensor installed outside the first circle in a region between the film formation surface of the substrate and the surface on which the plurality of evaporation sources are arranged. The film-forming apparatus of any one of 1 item|term. 19. The film forming apparatus according to any one of claims 3 to 18, wherein the second evaporation source has a smaller diameter than each of the first evaporation sources. A film forming method for forming an electrode layer of an organic EL display element using the film forming apparatus according to any one of claims 1 to 19 . A method of manufacturing an electronic device using the film forming method according to claim 20 .

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