Mist collection system, mist collection method, deposition method, and solid substance

Abstract

This mist collection system includes a mist supply device and a solidification device. The solidification device solidifies and stores mist that is obtained by atomizing a dispersion liquid containing particles and that is supplied from the mist supply device.

Description

Mist collection system, mist collection method, film formation method, and solid substance

[0001] The present invention relates to a mist collection system, a mist collection method, a film formation method, and a solid substance.

[0002] Conventionally, as a technique for forming a thin film on a substrate, a sputtering method as shown in Patent Document 1 has been used. The sputtering method requires film formation in an environment with pressure control.

[0003] Japanese Patent Application Laid-Open No. 2021-046354

[0004] A first aspect of the present invention is a mist collection system having a mist supply device and a solidification device, wherein the solidification device solidifies and stores the mist obtained by atomizing a dispersion liquid containing particles, which is the mist supplied from the mist supply device.

[0005] Another aspect of the present invention is a mist collection method for collecting mist using the mist collection system described in any of the above.

[0006] Another aspect of the present invention is a film formation method including a procedure for generating mist from a dispersion liquid containing particles, a procedure for storing the solid obtained by solidifying the mist, and a procedure for forming a film on a substrate with the mist generated from the solid.

[0007] Another aspect of the present invention is a solid substance formed by freezing mist generated from a dispersion liquid containing particles.

[0008] It is a schematic diagram showing an example of a mist collection system according to the first embodiment. It is a schematic diagram for explaining a modification example of the supply port. It is a schematic enlarged diagram showing an example of a part of the mist collection system in the first embodiment. It is a schematic diagram showing an example of a film formation apparatus in the first embodiment. It is a schematic diagram showing an example of a mist collection system according to Modification Example 1 of the first embodiment. It is a schematic diagram showing an example of a mist collection system according to Modification Example 2 of the first embodiment. It is a schematic diagram showing an example of a film formation apparatus in the second embodiment.

[0009] Hereinafter, a preferred embodiment of the mist collection system 100 according to an embodiment for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail with reference to the attached drawings. The following embodiment is for the purpose of explaining the present invention and is not intended to limit the present invention to the following content. In the drawings, positional relationships such as up, down, left, and right shall be based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios in the drawings are not limited to the ratios shown. In the following description, an XYZ Cartesian coordinate system is set up, and the X-axis direction, Y-axis direction, and Z-axis direction are defined according to the arrows shown in the drawings.

[0010] <First Embodiment> The mist collection system 100 according to the first embodiment will be described below.

[0011] Figure 1 is a schematic diagram showing an example of a mist collection system 100 according to the first embodiment. The mist collection system 100 of this embodiment comprises a mist generating unit 10, a solid substance acquisition unit 60, and a connecting pipe 20. The mist generating unit 10 functions as a mist supply device and generates mist 40. The solid substance acquisition unit 60 functions as a solidification device and solidifies the mist 40 generated by the mist generating unit 10 to acquire solid substance 50. The connecting pipe 20 connects the mist generating unit 10 and the solid substance acquisition unit 60.

[0012] The mist generating unit 10 comprises an outer container 12, an inner container 14, a gas inlet pipe 15, a lid material 16, and an ultrasonic transducer 17. The outer container 12 is a container that houses the inner container 14, the ultrasonic transducer 17, and the propagating liquid 38. The outer container 12 houses the inner container 14 and the propagating liquid 38 such that at least a portion of the inner container 14 is in contact with the propagating liquid 38.

[0013] The inner container 14 holds the dispersion liquid 30. The dispersion liquid 30 has particles 31 and a dispersion medium 32, and the dispersion liquid 30 is produced by dispersing the particles 31 in the dispersion medium 32.

[0014] The gas inlet pipe 15 supplies carrier gas 37 for transporting mist 40 to the inner container 14. The gas inlet pipe 15 is attached to the top of the inner container 14 or to the lid material 16. The tip of the gas inlet pipe 15 is a gas inlet 151, through which the carrier gas 37 for transporting mist 40 flows into the inner container 14. The position and configuration of the gas inlet pipe 15 and the gas inlet 151 are not particularly limited, and any configuration that can supply carrier gas 37 into the inner container 14 is sufficient.

[0015] The lid 16 is installed at the opening in the upper part of the inner container 14. The mist generating unit 10 does not necessarily have to have a lid 16. The lid 16 may also have one or more connection ports for connecting pipes or the like.

[0016] The ultrasonic transducer 17 generates vibrations. The vibrations generated by the ultrasonic transducer 17 are transmitted to the dispersion liquid 30 in the inner container 14 by the propagating liquid 38. The installation position of the ultrasonic transducer 17 is not limited, as long as the structure allows the vibrations of the ultrasonic transducer 17 to be transmitted to the dispersion liquid 30. When the vibrations of the ultrasonic transducer 17 are transmitted to the dispersion liquid 30, the mist generating unit 10 does not need to have an outer container 12 and a propagating liquid 38. In addition, any transducer that generates mist 40 can be used as the ultrasonic transducer 17, and it may not even be an ultrasonic transducer. The frequency of the ultrasonic transducer 17 can be set as appropriate, for example, from 100 Hz to 1,000,000 kHz. The output of the ultrasonic transducer 17 can be from 10 W to 200 W.

[0017] The connecting pipe 20 sends the mist 40 generated from the mist generating unit 10 to the solid substance acquisition unit 60 together with the carrier gas 37. The connecting pipe 20 can be a duct, pipe, tube, etc., but it is sufficient that it can at least send the mist 40 from the mist generating unit 10 to the solid substance acquisition unit 60, and its shape is not particularly limited. The material of the connecting pipe 20 can be metal, resin, vinyl, etc., but is not particularly limited. In addition, to reduce material loss due to mist 40 adhering to the inside of the connecting pipe 20, a water-repellent material may be used, or a water-repellent coating such as a water-repellent film may be applied to the inside of the connecting pipe 20. The connecting pipe 20 may also be cooled. The connecting pipe 20 is connected to or inserted into the internal container 14, and one end of the connecting pipe 20 on the mist generating unit 10 side is open and functions as a mist outlet 18.

[0018] In this embodiment, the solid substance acquisition unit 60 comprises a storage tank 61, a supply port 62, antifreeze 63, a cooling device 64, a lid material 65, and a discharge pipe 66. The solid substance acquisition unit 60 solidifies the mist 40 supplied from the mist generating unit 10 via the connecting pipe 20 to obtain solid substance 50. In this embodiment, the solid substance acquisition unit 60 obtains solid substance 50 by freezing the mist 40.

[0019] The storage tank 61 is a container for storing antifreeze 63 and solid material 50. The shape and material of the storage tank 61 are not limited. Examples of materials used for the storage tank 61 include plastic, metal, glass, and ceramics, but other materials may also be used. Examples of shapes for the storage tank 61 include cylindrical tanks and rectangular tanks, but other shapes are also possible. For example, it may have protrusions on the inside or outside, and the shape of the opening is not limited. The inside of the storage tank 61 may be an open system, a closed system, or may have some holes. Also, for example, the storage tank 61 may have a bag-shaped or pouch-shaped storage section inside. Hereinafter, the wall surface of the storage tank 61 refers to the structure that separates the storage tank 61 from the outside, and unless otherwise specified, it includes the sides and bottom surface.

[0020] The supply port 62 is located at the end of the connecting pipe 20, on the side of the solid substance acquisition section 60, and is provided inside the storage tank 61. The connecting pipe 20 is connected to or inserted into the storage tank 61, and the supply port 62 may be located on the wall of the storage tank 61, or it may be located inside the storage tank 61 other than on the wall. The shape of the supply port 62 is not limited.

[0021] Figure 2 is a schematic diagram illustrating a modified example of the supply port 62. As shown in this figure, the shape of the supply port 62 is not limited to the example shown in Figure 1. In Figure 2, for comparison, a supply port 62A is shown, which has an opening area equal to the cross-sectional area of ​​the connecting pipe 20 at the connection point between the storage tank 61 and the connecting pipe 20. The supply port 62B is configured such that a part of the connecting pipe 20 gradually tapers towards the tip. In this example, the connecting pipe 20 does not necessarily have to gradually taper towards the supply port 62B; for example, the connecting pipe 20 may have the same diameter to the tip, with a small-diameter hole (supply port 62) at the tip. Alternatively, the connecting pipe 20 may taper in one step or in multiple steps near the tip. That is, it is sufficient that the opening area of ​​the supply port 62 is relatively small compared to the cross-sectional area of ​​the connecting pipe 20.

[0022] The supply port 62C shown in Figure 2 has a filter shape, with multiple holes 622 opening in the filter section 621. The size, number, and arrangement of the holes 622 are not particularly limited. Furthermore, the filter section 621 is not particularly limited; it can be attached externally to the supply port 62, or the supply port 62 itself can be in the shape of a filter. For example, the connecting pipe 20 may have multiple filter sections 621 connected along its longitudinal direction. The material of the filter is not particularly limited; it can be metal, plastic, nonwoven fabric, cloth, etc. The filter may be made of a water-repellent material or may be treated with a water-repellent coating.

[0023] The supply port 62D shown in Figure 2 has multiple supply ports 623, formed when the connecting pipe 20 branches off near its tip. The number of supply ports 623 is not particularly specified, and the branched portion may be external, or the connecting pipe 20 itself may have a branched structure.

[0024] Let's return to the explanation in Figure 1. The antifreeze 63 is a liquid cooled by the cooling device 64 and solidifies by cooling the mist 40 supplied from the mist generating unit 10. That is, the antifreeze 63 cools a portion of the inside of the containment tank 61 so that the mist 40 is at a temperature below its freezing point. The components of the antifreeze 63 are not limited, and for example, ethanol, methanol, ethylene glycol, benzene, chloroform, hexane, toluene, and mixtures thereof can be used. It is preferable that the melting point of the antifreeze is lower than the melting point of the dispersion medium of the mist 40.

[0025] The cooling device 64 is a device for cooling the antifreeze 63. For example, the cooling device 64 uses a refrigerator that circulates a refrigerant to cool the antifreeze 63. The cooling device 64 cools the antifreeze 63 to a temperature of -80°C or lower. For example, the cooling device 64 cools the outer wall of the storage tank 61. The cooling device 64 may be installed on the bottom surface of the storage tank 61 or on the side surface.

[0026] The lid 65 is installed in the opening at the top of the storage tank 61. The solid material acquisition unit 60 does not necessarily have to have a lid 65. The lid 65 may also be provided with holes or connection mechanisms to other devices.

[0027] The discharge pipe 66 discharges the carrier gas 37 inside the containment tank 61 to the outside of the containment tank 61. One end of the discharge pipe 66 on the containment tank 61 side functions as an outlet 67. The outlet 67 only needs to be structured to exhaust the carrier gas 37 to the outside of the containment tank 61, and its position and shape are not limited. For example, the outlet 67 may simply be the opening of the pipe itself, or it may have a nozzle head attached, or it may be a hole provided in the cover material 16.

[0028] As an example, the supply port 62 is placed in the antifreeze 63. By placing the supply port 62 in the antifreeze 63, the solidification of the mist 40 can be promoted. The supply port 62 shown in Figure 1 is the opening at the tip of the connecting pipe 20 and is inserted into the antifreeze 63. For example, the supply port 62 may be provided on the side of the storage tank 61 and positioned lower vertically than the liquid surface of the antifreeze 63. In this example, the supply port 62 is not particularly limited in structure, as long as the supplied mist 40 is in direct contact with the antifreeze 63.

[0029] As another example, the supply port 62 is positioned vertically above the liquid surface of the antifreeze 63, and the mist 40 is discharged without direct contact with the antifreeze 63. In this example, the supply port 62 may face the liquid surface of the antifreeze 63. Mist 40 in contact with the liquid surface of the antifreeze 63, and mist 40 cooled to its freezing point near the liquid surface, are accelerated to solidify. The distance from the supply port 62 to the liquid surface can be appropriately adjusted according to the ejection velocity of the carrier gas 37, and is preferably 7 cm or less, more preferably 5 cm or less, and even more preferably 3 cm or less. In the following description, the state in which the mist 40 is cooled to below its freezing point near the liquid surface of the antifreeze 63 will be described as the state in which the mist 40 is in contact with the antifreeze 63.

[0030] (Method for producing solid material for film formation) The following describes a method for producing solid material for film formation using the mist collection system 100. First, the dispersion liquid 30 is placed in the inner container 14 and the lid material 16 is installed. The type of dispersion medium 32 used in the dispersion liquid 30 is not particularly limited, as long as the particles 31 can be dispersed. For example, as the dispersion medium 32, water, isopropyl alcohol (IPA), alcohols such as ethanol and methanol, acetone, dimethylformamide (DMF), dimethyl sulfosoxide (DMSO), ethyl acetate, acetic acid, tetrahydrofuran (THF), diethyl ether (DME), toluene, carbon tetrachloride, n-hexane, etc., and mixtures thereof can be used. Among these, the dispersion medium 32 preferably contains water, and more preferably is water, from the viewpoint of the dispersibility of the particles 31 and dielectric constant.

[0031] The type of particle 31 is not particularly limited, but inorganic oxides are preferred. The inorganic oxide used for the particle 31 is not particularly limited, but silicon dioxide, zirconium oxide, indium oxide, zinc oxide, tin oxide, titanium oxide, indium tin oxide (ITO), potassium tantalate, tantalum oxide, aluminum oxide, magnesium oxide, hafnium oxide, tungsten oxide, etc. It is even more preferable to use ITO particles. These may be used individually, or two or more may be used in any combination. The average particle size of the particle 31 is not particularly limited, but specifically it can be 1 nm to 10 μm. The particle 31 may have a particle size of 10 μm or more. In addition to the dispersion medium 32 and the particles 31, the dispersion liquid 30 may also contain a surfactant, etc.

[0032] Next, the ultrasonic transducer 17 of the mist generating unit 10 is activated. The vibrations of the ultrasonic transducer 17 are transmitted to the inner container 14 via the propagating liquid 38, and further transmitted to the dispersion liquid 30 inside the inner container 14. Due to the vibrations, the dispersion liquid 30 is atomized into mist 40. The mist 40 is a gas-liquid mixture, for example, in which fine droplets are dispersed and suspended in a gas. The particle size of the particles 31 contained in the mist 40 is such that it can be transported by the carrier gas 37, and is preferably 10 μm or less.

[0033] Carrier gas 37 flows into the inner container 14 from the gas inlet 151. The carrier gas 37 is not particularly limited, but a highly stable gas is desirable. For example, nitrogen, oxygen, air, helium, argon, xenon, or a combination thereof is preferred. The flow rate and velocity of the carrier gas 37 can be set as appropriate.

[0034] The generated mist 40, along with the carrier gas 37, passes through the mist outlet 18, the connecting pipe 20, and the supply port 62 in that order, and is released into the antifreeze 63. Upon contact with the antifreeze 63, the mist 40 solidifies and becomes a solid substance 50. The carrier gas 37 supplied into the containment tank 61 is released into the containment tank 61 from the liquid surface of the antifreeze 63 and discharged to the outside of the containment tank 61 through the outlet 67.

[0035] As described above, in this embodiment, since the mist 40 is supplied directly to the antifreeze 63, the suspension of the mist 40 inside the containment tank 61 is suppressed. Therefore, more of the mist 40 is converted into solid material 50 and stored in the containment tank 61. As a result, the amount of mist 40 discharged from the outlet 67 is reduced, and the efficiency of generating the solid material 50 used for film formation is improved.

[0036] Furthermore, it is not necessary for the mist 40 to remain completely inside the antifreeze 63; some of the mist 40 may float in the containment tank 61 and may not remain there.

[0037] In addition, when mist 40 and carrier gas 37 are introduced into the antifreeze 63, bubbles are formed in the antifreeze 63. Some of these bubbles burst at the surface of the antifreeze 63, and the unfrozen mist 40, along with the carrier gas 37 contained within the bubbles, may be released into the containment tank 61. In that case, the mist 40 may float in the containment tank 61 and be discharged from the outlet 67. Furthermore, if the bubble diameter is large, the solidification of the mist 40 may be suppressed.

[0038] In this embodiment, the bubble diameter discharged from the supply port 62 may be configured to be small. For example, the supply port 62 with the pattern shown in Figure 2 may be used, or a nozzle configured to produce smaller bubbles may be connected to the supply port 62. As the antifreeze 63 comes into contact with the surface of the bubbles, the droplets inside the bubbles become more likely to solidify. Therefore, by discharging small bubbles from the supply port 62, the efficiency of the mist 40 becoming a solid substance 50 can be increased.

[0039] Figure 3 is a schematic enlarged view showing a partial example of the mist collection system 100 in the first embodiment. The mist 40 generated from the dispersion liquid 30 contains particles 41 and a dispersion medium 42. The particles 41 and the dispersion medium 42 are formed when the particles 31 and dispersion medium 32 contained in the dispersion liquid 30 are atomized and suspended. Note that the average particle size of particles 31 and the average particle size of particles 41 are different. More specifically, among the particles 31 contained in the dispersion medium 32, the particles 31 with a larger particle size are heavier and have a larger volume compared to the particles 31 with a smaller particle size, and are therefore more difficult to atomize. Consequently, the average particle size of particles 31 is larger than the average particle size of particles 41 contained in the mist 40.

[0040] In the solid substance acquisition unit 60, the mist 40 solidifies, and solid substance 50 is generated. The solid substance 50 contains particles 51 and frozen material 52. The particles 51 and frozen material 52 are formed when the particles 41 and dispersion medium 42 contained in the mist 40 are frozen, respectively. The solid substance 50 may also contain a portion of antifreeze 63. Therefore, the average particle size of the particles 51 is different from the average particle size of the particles 31 contained in the dispersion liquid 30, and the average particle size of the particles 31 is larger than the average particle size of the particles 51. The average particle size of the particles 51 is preferably 100,000 nm or less, more preferably 10,000 nm or less, even more preferably 1,000 nm or less, and even more preferably 100 nm or less. However, some particles with a particle size of 100,000 nm or more may be included.

[0041] The method for determining the average particle size in this embodiment is described below. First, an image of the particles is taken using a scanning electron microscope (SEM). Next, preprocessing is performed to remove noise from the obtained image and adjust the contrast in order to clearly observe the particles. After that, the image is binarized to clearly distinguish the particles from the background. Next, each particle is labeled for identification, and the area and perimeter of each particle are measured from the image to calculate the equivalent diameter of a circle. The average particle size is obtained by calculating the average of all the particle diameters captured in the image.

[0042] In this embodiment, the mist 40 is instantaneously frozen. Since the droplets in the mist 40 are in a state where the dispersion medium 42 surrounds the particles 41, the instantaneously frozen solid substance 50 is also in a state where the frozen body 52 surrounds the particles 51. Generally, the aggregation of particles increases in proportion to the number of contacts between the particles. Therefore, in order to prevent aggregation, it is useful to reduce the number of contacts between the particles. The solid substance 50 in this embodiment is fixed in a state where the frozen body 52 surrounds the particles 51, so the contact between the particles 51 is less, and it can be held in a state where it is difficult to aggregate. It is possible to create a dispersion liquid with reduced aggregation of the particles 51 as compared to the case where the mist 40 is collected in a liquid state and used as a dispersion liquid for film formation. In this embodiment, even if not all of the mist 40 is instantaneously frozen, a part thereof may take some time to freeze.

[0043] (Film formation using particles 51) FIG. 4 is a schematic diagram showing an example of a film forming apparatus 200 in the first embodiment. This film forming apparatus 200 thaws the solid substance 50 collected by the mist collection system 100 and uses it to generate a mist 73, and forms a film on an object. Mist film formation using the film forming apparatus 200 can be performed under atmospheric pressure, so the configuration of the apparatus is very simple compared to other film forming methods.

[0044] The film forming apparatus 200 includes a mist generating section 80, a connecting pipe 86, and a film forming section 90. The mist generating section 80 includes an outer container 82, an ultrasonic vibrator 83, an inner container 84, and a gas inflow pipe 85. The outer container 82 houses the inner container 84 and the propagation liquid 88. The inner container 84 houses the dispersion liquid 70. The dispersion liquid 70 is formed by dispersing particles 71 in a dispersion medium 72. The connecting pipe 86 sends the mist 73 generated from the mist generating section 10 to the film forming section 90 together with the carrier gas 87 supplied via the gas inflow pipe 85. The film forming section 90 includes a film forming tank 92. The film forming tank 92 can hold the film forming object T inside.

[0045] The mist generating unit 80 generates mist 73 by operating an ultrasonic transducer 83, similar to the mist generating unit 10 described above. The generated mist 73 passes through the connecting pipe 86 together with the carrier gas 87 supplied from the gas inlet pipe 85 and is released into the film deposition tank 92. When the mist 73 released into the film deposition tank 92 comes into contact with the object to be deposited T, a thin film is formed on the object T.

[0046] In this embodiment, the film-forming apparatus 200 thaws a solid substance 50, liquefies it, and stores the resulting dispersion 70 in an internal container 84 for use in film formation. More specifically, for example, the solid substance 50 stored in the storage tank 61 is separated from the antifreeze 63 by filtration or the like at its solid temperature and collected. The solid substance 50 is then transferred to the internal container 84 of the mist generating unit 80 and can be used for mist film formation. In this case, thawing the solid substance 50 causes the particles 51 to become particles 71, and the frozen material 52 becomes the dispersion medium 72. In addition, to adjust the concentration of the dispersion medium 70, additional dispersion medium 72 may be added to the internal container 84. The thawing of the solid substance 50 may be performed before or after it is stored in the internal container 84 of the mist generating apparatus.

[0047] In addition, the resulting dispersion 70 for film formation may undergo other processing or steps before being used for film formation. For example, it may be subjected to steps such as concentration adjustment, stirring, addition of surfactants, heating and cooling. The solid substance 50 and the dispersion 70 for film formation can be delivered to other companies or distributed. The particles 51 may also be extracted by thawing the solid substance 50 and filtering or centrifuging it. The extracted particles 51 can be prepared again with the dispersion medium 72 to make a dispersion for mist film formation, or a mist can be prepared using a different dispersion medium to make a dispersion for mist film formation.

[0048] Generally, when generating mist from a dispersion for the purpose of mist film formation, there are limitations on the size of particles that can be included in the mist. Particles larger than a certain specific size remain in the dispersion without being included in the mist. As mist generation continues, these large particles accumulate in the dispersion. Since the dispersion medium and the small particles that can be included in the mist are gradually consumed by mist generation, it becomes necessary to add dispersion in order to continue film formation. However, if the dispersion is added as it is, the particles of the added dispersion are added to the large particles that have accumulated in the inner container. As a result, the particle concentration in the dispersion increases. When the particle concentration increases, the possibility of particle aggregation increases. Particle aggregation makes mist generation difficult and also has an adverse effect on film formation accuracy.

[0049] In addition, when removing the dispersion in which large particles remain before adding a new dispersion, it is necessary to interrupt mist generation at least while removing the dispersion. Therefore, removal of the dispersion cannot be applied in the case of continuous film formation.

[0050] The mist collection system 100 in the present embodiment can select particles 51 of a size that can be misted by solidifying the mist 40. In other words, the solid substance acquisition unit 60 functions as a mechanism for collecting particles 51 of a size that can be misted.

[0051] When comparing the dispersion 30 and the dispersion 70 for film formation, the particles 71 contained in the dispersion 70 for film formation have a smaller average particle size compared to the particles 31 contained in the dispersion 30. This is because the particles 71 are composed of the particles 41 contained in the mist 40 generated in the mist generation unit 10, and the large particles not contained in the mist 40 remain in the dispersion 30. Note that it is not that large particles not contained in the mist 40 are not allowed to be contained in the dispersion 70, nor that particles formed by aggregation of a plurality of particles are not allowed to be contained in the dispersion 70.

[0052] The particles 71 contained in the dispersion 70 are used for film formation, so it is desirable that they have a particle size that can be incorporated into a mist. The average particle size of the particles 71 is the same as the average particle size of the particles 51, preferably 100,000 nm or less, more preferably 10,000 nm or less, even more preferably 1,000 nm or less, and even more preferably 100 nm or less. However, some particles with a particle size of 100,000 nm or more may be included.

[0053] <First Embodiment: Modification 1> Next, the mist collection system 100 in Modification 1 of the first embodiment will be described. The differences from the above-described embodiment will be explained below.

[0054] Figure 5 is a schematic diagram showing an example of a mist collection system 100 according to Modification 1 of the first embodiment. In this modification, the solid substance acquisition section 60 functions as a freezer. The containment tank 61 is the wall of the freezer, and its material is not limited. For example, stainless steel, glass fiber reinforced plastic (FRP), aluminum, polyvinyl chloride (PVC), synthetic rubber, high-density polyethylene (HDPE), etc., can be used for the containment tank 61.

[0055] The cooling device 64 is a device for cooling the storage tank 61. The configuration of the cooling device 64 is not limited; for example, a refrigerator that circulates a refrigerant to lower the external temperature can be used, similar to the cooling device 64 shown in Figure 1. The cooling device 64 may be provided on the bottom surface of the storage tank 61 or on the side surface. The cooling device 64 cools the inside of the storage tank 61 to, for example, -100°C to -80°C. Antifreeze 63 may be stored in the storage tank 61. In that case, the supply port 62 of the connecting pipe 20 does not have to be located inside the antifreeze 63. With this configuration, the mist sent into the storage tank 61 is cooled and solidified, and accumulates as solid matter 50.

[0056] The solid substance 50 obtained by this modification can be used for mist film formation by placing it in the internal container 84 of the mist generating unit 80 of the film formation apparatus 200, as in the embodiment described above. As in the example described above, the solid substance 50 may be thawed either before or after placing it in the internal container 84 of the mist generating unit 80.

[0057] As described above, the mist collection system 100 of this modified form can select particles 51 of a size that can be atomized. Furthermore, by cooling the containment tank 61, the discharge of mist 40 to the outside of the containment tank 61 via the discharge pipe 66 is suppressed, thereby enabling the efficient generation of solid matter 50.

[0058] <First Embodiment: Modification 2> Next, the mist collection system 100 in Modification 2 of the first embodiment will be described. The differences from the above-described embodiment will be explained below.

[0059] Figure 6 is a schematic diagram showing an example of a mist collection system 100 according to a modification 2 of the first embodiment. In this modification, the solid substance acquisition unit 60 includes a porous member 68 for cooling the mist 40. The material of the porous member 68 is not limited, and for example, carbon, alumina, zirconia, etc. can be used. The porous material is cooled to a temperature below the freezing point of the mist 40, and the solid substance 50 is contained in its pores. For example, the porous material is -100°C to -80°C. The porous member 68 may be placed inside a containment tank, which is not shown. Methods for cooling the porous material to a temperature below the freezing point of the mist 40 include immersing it in antifreeze at a temperature below the freezing point of the mist 40, or placing it in a freezer for a certain period of time.

[0060] In this modified example, the supply port 62 is located on or inside the porous member 68. As a result, the mist 40 discharged from the supply port 62 enters the pores of the porous member 68. The mist 40 is cooled and solidified by the porous material. Because the mist 40 enters the pores of the porous member 68, even if the mist 40 is not frozen instantly, its suspension within the mist containment tank is suppressed, and it is less likely to be discharged from the outlet. As a result, the mist collection efficiency is increased. Subsequently, as an example, the solid substance 50 is melted by raising the temperature of the porous material. The substance obtained by melting is contained as a dispersion liquid 70 in the mist generating unit 10 of the aforementioned film-forming apparatus 200. As another example, the solid substance 50 may be removed from the porous material while remaining solid.

[0061] As described above, even in the mist collection system 100 in this modified example, particles 51 of a size that can be atomized can be efficiently selected.

[0062] <Second Embodiment> Next, the film deposition apparatus 300 in the second embodiment will be described. The differences from the above-described embodiment will be explained below.

[0063] Figure 7 is a schematic diagram showing an example of a film deposition apparatus 300 in the second embodiment. This film deposition apparatus 300 performs film deposition using a roll-to-roll method or a roll-to-sheet method, which continuously deposits films onto a roll-shaped substrate. This method is expected to improve the efficiency, simplify, and increase the yield of the manufacturing process.

[0064] The roll-to-roll method refers to a method in which a roll of film substrate is unwound, continuously deposited, and then re-wound into a roll. The roll-to-sheet method refers to a method in which a roll of film substrate is unwound, continuously deposited, and then cut into sheets. When using a flexible substrate compatible with the roll-to-roll or roll-to-sheet method, the thickness and rigidity (Young's modulus) of the substrate should be within a range that prevents buckling, folds, or irreversible wrinkles from occurring in the substrate as it passes through the transport path of the exposure equipment, etc.

[0065] The film deposition apparatus 300 includes a mist supply unit 310, a transport unit 315, a mist recovery unit 320, a flow straightening member 325, a mist intake unit 330, and a solid material acquisition unit 340. The mist supply unit 310 sprays mist 318 containing particles that will become the material for film deposition toward the substrate S. The mist 318 sprayed by the mist supply unit 310 may be mist generated by a mist generating unit (not shown) connected to the mist supply unit 310, or it may be mist generated by the mist supply unit 310.

[0066] The configuration of the mist supply unit 310 is not limited. For example, the mist supply unit 310 generates mist 318 by vibrating a dispersion liquid 70 containing particles with an ultrasonic transducer 83, similar to the mist generating unit 80 of the film deposition apparatus 200 shown in Figure 4, and ejects the mist 318 toward the substrate S using a carrier gas 317. For example, the mist supply unit 310 is provided with a slit-shaped nozzle parallel to the short side of the substrate (the direction perpendicular to the transport direction), and ejects the mist 318 in the direction of arrow (a). The ejected mist 318 flows along the surface of the substrate S in the +X direction toward the negative pressure (reduced pressure) formed in the recovery port formed at the bottom of the mist recovery unit 320 downstream in the substrate transport direction (direction of arrow (b)), and adheres to the surface of the substrate S.

[0067] The transport unit 315 supports the substrate S in a flat position and rotates around the Y-axis in Figure 7, transporting the supported substrate S in the direction of arrow (b). The transport unit 315 also functions as an adhesion member that adheres the mist 318 to the substrate S by supporting it.

[0068] The mist recovery unit 320 is located downstream of the mist supply unit 310 in the substrate transport direction and recovers mist 318 that does not adhere to the substrate S. That is, the mist recovery unit 320 functions as a recovery member that recovers excess mist 318 from the adhering member. For example, the mist recovery unit 320 is provided with a slit-shaped nozzle parallel to the short side direction of the substrate S (the direction perpendicular to the transport direction), and the mist 318 and carrier gas 317 are sucked in in the direction of arrow (c) by the negative pressure generated by the function of the mist suction unit 330.

[0069] The rectifier member 325 guides the mist 318 and carrier gas 317 to flow smoothly from the mist supply unit 310 to the mist collection unit 320. For example, the rectifier member 325 is a horizontal rectangular plate, with flat plates hanging down and connected to each of its two opposing sides (the two sides extending in the -X to X direction in Figure 7), thereby suppressing the mist 318 and carrier gas 317 from flowing out of the substrate S.

[0070] The mist intake unit 330 sends the air drawn in from the air intake to the exhaust port by supplying gas from the gas inlet. As shown by arrow (d), when gas is supplied to the mist intake unit 330, the mist 318 collected from the vicinity of the substrate S by the mist recovery unit 320 flows in the direction shown by arrow (e) and is transported to the solid material acquisition unit 340.

[0071] The solid substance acquisition unit 340, similar to the solid substance acquisition unit 60 in the first embodiment, solidifies the mist 318 collected by the mist recovery unit 320 to obtain solid substance 50. The solid substance 50 is contained in the solid substance acquisition unit 340.

[0072] As described above, according to this embodiment, the recovered excess mist can be solidified, improving the mist recovery efficiency. Since aggregation of the solidified film-forming particles is suppressed, it contributes to improved film-forming efficiency when reused for mist film formation.

[0073] 10・80: Mist generating unit, 12・82: Outer container, 14・84: Inner container, 15・85: Gas inlet pipe, 16・65: Lid material, 17・83: Ultrasonic transducer, 18: Mist outlet, 20・86: Connecting pipe, 30・70: Dispersion liquid, 31・41・51・71: Particles, 32・42・72: Dispersion medium, 37・87・317: Carrier gas, 38・88: Propagating liquid, 40・73・318: Mist, 50: Solid substance, 52: Frozen substance, 60・340: Solid substance acquisition unit, 61: Storage tank, 62・62A, 62B, 62C, 62D, 623: Supply port, 63: Antifreeze, 64: Cooling device, 66: Discharge pipe, 67: Discharge port, 68: Porous material, 90: Film formation section, 92: Film formation tank, 100: Mist collection system, 151: Gas inlet, 200, 300: Film formation apparatus, 310: Mist supply section, 315: Transport unit, 320: Mist recovery section, 330: Mist intake section, 621: Filter section, 622: Hole, (a), (b), (c), (d), (e): Arrow, S: Substrate, T: Film formation target

Claims

1. A mist collection system comprising a mist supply device and a solidification device, wherein the solidification device solidifies and contains the mist supplied from the mist supply device, which is a dispersion containing particles atomized into mist.

2. The mist collection system according to claim 1, wherein the solidification device freezes the mist to obtain a solid.

3. The mist supply device contains the dispersion liquid, and the average particle size of the first particles contained in the dispersion liquid contained in the mist supply device and the second particles contained in the solid formed by the solidification device are different, as described in claim 1.

4. The mist collection system according to claim 2 or 3, wherein the solid particles are surrounded by the dispersion medium of the dispersion liquid.

5. The mist collection system according to any one of claims 2 to 4, wherein the solidification device comprises a containment tank for containing the solid and a cooling member for cooling the outer wall of the containment tank.

6. The mist collection system according to any one of claims 1 to 5, wherein the solidification device comprises a containment tank for containing a liquid for cooling the mist, and a supply port for supplying the mist to the containment tank.

7. The mist collection system according to claim 6, wherein the supply port is located in the liquid.

8. The mist collection system according to any one of claims 2 to 5, wherein the solidification device has a porous member for cooling the mist, and the porous member contains the solid within its pores.

9. The mist collection system according to any one of claims 1 to 8, wherein the particles include at least one of silicon dioxide, zirconium oxide, indium oxide, zinc oxide, tin oxide, titanium oxide, indium tin oxide, potassium tantalate, tantalum oxide, aluminum oxide, magnesium oxide, hafnium oxide, and tungsten oxide.

10. The mist collection system according to any one of claims 1 to 9, wherein the dispersion comprises, as a dispersion medium, at least one of water, isopropyl alcohol (IPA), ethanol, methanol, acetone, dimethylformamide (DMF), dimethyl sulfosoxide (DMSO), ethyl acetate, acetic acid, tetrahydrofuran (THF), diethyl ether (DME), toluene, carbon tetrachloride, and n-hexane.

11. The mist collection system according to any one of claims 1 to 10, wherein the particle size of the particles contained in the solid formed by solidifying the mist and contained in the solidification device is 10 μm or less.

12. A mist collection system according to any one of claims 1 to 11, comprising: an adhesion member for adhering the mist to a substrate; and a recovery member for recovering excess mist from the adhesion member, wherein the mist supply device supplies the mist to the adhesion member; and the solidification device solidifies and stores the mist recovered from the adhesion member by the recovery member.

13. A mist collection method comprising collecting mist using a mist collection system according to any one of claims 1 to 12.

14. A method for forming a film, comprising: a step of generating a mist from a dispersion containing particles; a step of containing a solid obtained by solidifying the mist; and a step of forming a film on a substrate with the mist generated from the solid.

15. A solid substance obtained by freezing a mist generated from a dispersion containing particles.

16. The solid substance according to claim 15, wherein the dispersion medium of the dispersion liquid surrounds the particles.

17. The solid substance according to claim 15 or 16, wherein the particles comprise at least one of silicon dioxide, zirconium oxide, indium oxide, zinc oxide, tin oxide, titanium oxide, indium tin oxide, potassium tantalate, tantalum oxide, aluminum oxide, magnesium oxide, hafnium oxide, and tungsten oxide.

18. The solid substance according to any one of claims 15 to 17, wherein the dispersion contains at least one of water, isopropyl alcohol (IPA), ethanol, methanol, acetone, dimethylformamide (DMF), dimethyl sulfosoxide (DMSO), ethyl acetate, acetic acid, tetrahydrofuran (THF), diethyl ether (DME), toluene, carbon tetrachloride, and n-hexane as a dispersion medium.

19. The solid substance according to any one of claims 15 to 18, wherein the particle size of the particles is 10 μm or less.

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