Film forming method, film forming apparatus, and laminate

Abstract

The present invention is a film forming method including a step for atomizing a source material solution and forming a source material mist, a step for mixing the source material mist and a carrier gas and forming a gaseous mixture, a step for placing a substrate on a stage, a film forming step for supplying the gaseous mixture to the substrate from a gaseous mixture supply means and forming a film on the substrate via a thermal reaction, and an exhausting step for exhausting the post–film forming gaseous mixture using an exhausting means, wherein: a channel plate is disposed above the substrate so as to face the substrate with space therebetween, and a gaseous mixture flow is formed in which the gaseous mixture flows directly from the gaseous mixture supply means toward the exhausting means, through the space above the substrate, so as to follow at last a portion of a main surface of the substrate; and in the film forming step and the exhaust step, at least the temperature T1 of the gaseous mixture supply means and the temperature T2 of the channel plate are controlled. Thereby, a film forming method and a film forming apparatus are provided that can reliably manufacture a high-quality film on a large-diameter substrate surface.

Description

[Technical Field]

[0001] The present invention relates to a film forming method and a film forming apparatus. [Background technology]

[0002] As a method capable of forming epitaxial films at low temperatures and atmospheric pressure, a film formation method using water particles, such as mist CVD, is known. Patent Document 1 shows a film formation apparatus that forms a film by supplying a raw material mist to a substrate from a nozzle positioned at an angle relative to the substrate. Patent Document 2 also describes a film formation method in which the raw material mist is transported into a reaction vessel by a carrier gas and a swirling flow is generated to cause the mist to react with the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-142637 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-146442 Summary of the Invention [Problem to be solved by the invention]

[0004] However, these conventional deposition systems lack sufficient control of the mist on the substrate, making it difficult to deposit a uniformly thick film on a practically large-diameter substrate. Furthermore, the mist temperature changes due to continuous heating of the nozzle or deposition chamber, which often leads to the evaporation of the mist, resulting in powder deposition on the substrate surface and, in the case of crystal growth, the formation of abnormally grown grains. These contaminants not only adversely affect the characteristics of semiconductor devices, but also act as a stress source, causing widespread cracking in the film if film growth continues over the contaminants, resulting in reduced film quality and yield.

[0005] The present invention has been made to solve the above problems, and an object of the present invention is to provide a film-forming method and a film-forming apparatus that can stably produce a high-quality film on the surface of a large-diameter substrate. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides a method for producing a raw material mist by atomizing a raw material solution, mixing the raw material mist with a carrier gas to form a mixture; placing a substrate on a stage; a film-forming step of supplying the gas mixture from a gas mixture supply means to the substrate and forming a film on the substrate by a thermal reaction; an exhaust step of exhausting the gas mixture after the film formation by an exhaust means; A film forming method comprising: a channel plate is disposed on the base body so as to face the base body with a space therebetween; forming a mixed gas flow that flows linearly from the mixed gas supply means toward the exhaust means in the space above the base so that the mixed gas flows along at least a part of the main surface of the base; The present invention provides a film formation method in which at least the temperature T1 of the gas mixture supply means and the temperature T2 of the channel plate are controlled in the film formation step and the exhaust step.

[0007] This type of film formation method suppresses deterioration of the raw material mist and generation of powder, thereby suppressing the formation of defects and maintaining a good raw material yield, making it a film formation method that can stably produce high-quality films on the surfaces of large-diameter substrates.

[0008] At this time, the temperature T3 of the exhaust means may be further controlled.

[0009] Such a film formation method allows the gas mixture to be discharged more efficiently, and therefore provides a film formation method that can more stably produce high-quality films.

[0010] In addition, the present invention provides a method for producing a raw material mist by atomizing a raw material solution; mixing the raw material mist with a carrier gas to form a mixture; placing a substrate on a stage; a film-forming step of supplying the gas mixture from a gas mixture supply means to the substrate and forming a film on the substrate by a thermal reaction; an exhaust step of exhausting the gas mixture after the film formation by an exhaust means; A film forming method comprising: a channel plate is disposed on the base body so as to face the base body with a space therebetween; forming a mixed gas flow that flows linearly from the mixed gas supply means toward the exhaust means in the space above the base so that the mixed gas flows along at least a part of the main surface of the base; The present invention provides a film formation method in which at least the temperature T2 of the channel plate is controlled in the film formation step and the exhaust step.

[0011] This type of film formation method suppresses deterioration of the raw material mist and generation of powder, thereby suppressing the formation of defects and maintaining a good raw material yield, making it a film formation method that can stably produce high-quality films on the surfaces of large-diameter substrates.

[0012] At this time, the temperature T3 of the exhaust means may be further controlled.

[0013] Such a film formation method allows the gas mixture to be discharged more efficiently, and therefore provides a film formation method that can more stably produce high-quality films.

[0014] The present invention also provides a method for producing a raw material mist by atomizing a raw material solution; a carrier gas supply means for transporting the raw material mist; a gas mixture supply means for supplying a gas mixture obtained by mixing the raw material mist and the carrier gas to a substrate surface; a stage on which the substrate is placed; an exhaust means for exhausting the air-fuel mixture; a channel plate disposed on the base body so as to face the base body with a space therebetween; The present invention provides a film forming apparatus comprising a temperature control means for controlling at least the temperature T1 of the gas mixture supply means and the temperature T2 of the channel plate.

[0015] With such a film formation apparatus, deterioration of the raw material mist and generation of powder are suppressed, thereby suppressing the formation of defects and maintaining a good raw material yield, making it possible to produce a film formation apparatus that can stably produce high-quality films on the surface of large-diameter substrates.

[0016] In this case, the temperature control means may further include a temperature control means for controlling the temperature T3 of the exhaust means.

[0017] Such a film forming apparatus can discharge the gas mixture more efficiently, and can therefore be a film forming apparatus that can more stably produce high-quality films.

[0018] The present invention also provides a crystal substrate, an epitaxially grown crystal film formed on the crystal substrate; A laminate comprising: The density of foreign particles with a diameter of 0.3 μm or more on the surface of the crystal film is 1 cm -2 There is provided a laminate comprising:

[0019] Such a laminate provides a high quality film on the surface of a large diameter substrate.

[0020] In this case, the thickness of the crystal film is preferably 0.3 μm or more.

[0021] The laminate of the present invention is more preferably such a laminate. [Effects of the Invention]

[0022] According to the present invention, a highly productive film-forming method and film-forming apparatus are provided that are capable of stably producing high-quality films on the surfaces of large-diameter substrates. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a diagram showing an embodiment of a film forming apparatus according to the present invention; [Figure 2] FIG. 2 is a diagram showing one embodiment of a film forming unit according to the present invention. [Figure 3] 10A and 10B are diagrams showing another embodiment of the film forming unit according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] As described above, there has been a need for the development of a film formation method and film formation apparatus that can stably produce high-quality films on the surfaces of large-diameter substrates.

[0025] As a result of extensive research into the above-mentioned problems, the inventors have found that by placing a channel plate on a substrate so as to face the substrate across a space and controlling the temperature T1 of the gas mixture supply means and the temperature T2 of the channel plate, it is possible to stably produce a high-quality film on the surface of a large-diameter substrate, and have completed the present invention.

[0026] That is, the present invention provides a method for producing a raw material mist by atomizing a raw material solution; mixing the raw material mist with a carrier gas to form a mixture; placing a substrate on a stage; a film-forming step of supplying the gas mixture from a gas mixture supply means to the substrate and forming a film on the substrate by a thermal reaction; an exhaust step of exhausting the gas mixture after the film formation by an exhaust means; A film forming method comprising: a channel plate is disposed on the base body so as to face the base body with a space therebetween; forming a mixed gas flow that flows linearly from the mixed gas supply means toward the exhaust means in the space above the base so that the mixed gas flows along at least a part of the main surface of the base; In the film forming step and the exhaust step, at least the temperature T1 of the gas mixture supply means and the temperature T2 of the channel plate are controlled.

[0027] In addition, the present invention provides a method for manufacturing a liquid feedstock, comprising: atomizing means for atomizing a raw material solution to form a raw material mist; a carrier gas supply means for transporting the raw material mist; a gas mixture supply means for supplying a gas mixture obtained by mixing the raw material mist and the carrier gas to a substrate surface; a stage on which the substrate is placed; an exhaust means for exhausting the air-fuel mixture; a channel plate disposed on the base body so as to face the base body with a space therebetween; The present invention provides a film forming apparatus comprising a temperature control means for controlling at least the temperature T1 of the gas mixture supply means and the temperature T2 of the channel plate.

[0028] The present invention will be described in detail below with reference to the drawings, but the present invention is not limited thereto.

[0029] [Film forming equipment] First, an example of a film forming apparatus that can be used in the film forming method according to the present invention will be described. A typical example of a film formation apparatus that can be used in the film formation method according to the present invention is shown in Fig. 1. However, the film formation apparatus that can perform the film formation method according to the present invention is not limited to the film formation apparatus shown in Fig. 1.

[0030] The film forming apparatus 1 shown in FIG. 1 includes a carrier gas 11, a carrier gas pipe 12, an atomizing means 20, a mist pipe 24, a gas mixture supply means 35, a stage 32, a channel plate 31, and an exhaust means 36. A substrate 34 on which a film is to be formed is placed on the stage 32. The gas mixture supply means 35 and the channel plate 31 are equipped with temperature control units 35b and 31b, respectively, which are connected to a temperature control unit 37 via a connection unit 38 to form a temperature control unit. The carrier gas 11 and the carrier gas pipe 12 form a carrier gas supply means 10. The gas mixture supply means 35, the stage 32, the channel plate 31, the exhaust means 36, the temperature control unit 37, and the connection unit 38 form a film forming unit 30. 35a denotes an outlet, and 36a denotes an exhaust port.

[0031] A raw material solution 21 is stored as a raw material inside the atomization means 20. The raw material solution 21 is not particularly limited as long as it is a solution that can be atomized (also called "misted"), and an aqueous solution containing a raw material according to the purpose, or a solution of an organic solvent such as alcohols, ketones, esters, ethers, amides, halogenated solvents, or aromatic compounds can be used. The raw material solution 21 is atomized by a known means to form a raw material mist 22 .

[0032] A carrier gas 11 is further supplied to the atomization means 20 and mixed with the raw material mist 22 to form a gas-air mixture 23. The carrier gas supply means 10 and the atomization means 20 can be said to constitute a mechanism 40 that forms the gas-air mixture 23.

[0033] A substrate 34 is placed on the stage 32, and the substrate 34 may be heated to a temperature suitable for film formation by a heating means (not shown). The air-fuel mixture 23 is transported through a mist pipe 24 and supplied to an air-fuel mixture supply means 35 .

[0034] The gas mixture 33 is supplied from the gas mixture supply means 35 to a space 39 formed between the channel plate 31 and the stage 32, and while flowing parallel to the substrate mounting surface of the stage 32, is supplied to the substrate 34 mounted on the stage 32, particularly to the surface of the substrate 34. In this process, the gas mixture 33 reacts on the substrate 34, and a film is formed on the substrate 34. During this time, the temperature of the gas mixture supply means 35 and the channel plate 31 is controlled by the temperature control unit 37 to a temperature suitable for film formation.

[0035] The surplus gas-air mixture 33 that did not contribute to film formation and by-products generated during the reaction of the gas-air mixture 33 on the substrate 34 are sucked out as the gas-air mixture after film formation by the exhaust means 36 and discharged to the outside of the system. The exhaust gas from the exhaust means 36 may be treated by a particle collector or scrubber (not shown) as needed.

[0036] The atomization of the raw material solution 21 is not particularly limited as long as it can atomize or turn the raw material solution 21 into droplets, and any known means may be used. However, in the present invention, an atomization means 20 using ultrasonic waves is preferred. The mist or droplets obtained using ultrasonic waves are preferable because they have an initial velocity of zero and float in the air. For example, rather than being sprayed like a spray, the mist floats in space and can be transported as a gas, which is highly suitable because it is not damaged by collision energy. The droplet size is not particularly limited and may be on the order of a few millimeters, but is preferably 50 μm or less, and more preferably 0.1 to 10 μm.

[0037] The carrier gas 11 is not particularly limited, and suitable examples include air, oxygen, ozone, inert gases such as nitrogen and argon, and reducing gases such as hydrogen gas and forming gas. The carrier gas 11 may be one type or two or more types. The flow rate of the carrier gas may be appropriately set depending on the size of the substrate and the size of the film formation section, and may be, for example, about 0.01 to 100 L / min.

[0038] Although not shown, it is also possible to adjust the ratio of the raw material mist 22 to the carrier gas 11 by further adding a dilution gas. The flow rate of the dilution gas may be set appropriately, for example, to 0.1 to 10 times that of the carrier gas. The dilution gas may be supplied, for example, downstream of the atomization means 20. The dilution gas may be the same as the carrier gas 11, or may be different.

[0039] The film formation may be carried out under any of atmospheric pressure, elevated pressure, and reduced pressure, but is preferably carried out under atmospheric pressure in terms of equipment cost and productivity.

[0040] 1 shows a configuration in which one atomization means 20 is used, the film formation apparatus 1 that can be used in the film formation method of the present invention is not limited to this, and multiple atomization means 20 can also be connected in series or parallel. In this case, each atomization means 20 may be used to store a different raw material solution, or the same raw material solution. Furthermore, each raw material solution may be atomized individually and supplied independently to the gas mixture supply means 35, or multiple types of raw material mists may be mixed and then supplied to the gas mixture supply means 35.

[0041] The mist piping 24 is not particularly limited as long as it is sufficiently stable against the raw material solution 21 used and the temperatures at the interface between the gas mixture supply means 35 and the carrier gas piping 12, and can be made of resin, metal, glass, or a combination of these materials depending on the purpose.

[0042] The shape and supply method of the gas-air mixture supply means 35 are not particularly limited, and a wide variety of known gas-air mixture supply means can be applied. The shape of the discharge port 35a is not particularly limited, and may include a single or multiple circles, ellipses, or polygons. However, to make the flow of the gas-air mixture 33 a more uniform laminar flow, it is preferable to use a single or multiple slit-like shape with a ratio of the minor axis length to the major axis length of approximately 10 or more. In this case, the longitudinal length of the discharge port 35a can be set to a length sufficient to match the shape of the base 34.

[0043] Furthermore, the gas mixture supply means 35 is not particularly limited as long as it is sufficiently stable against the raw material solution 21 used and the temperature at which it is used, and can be made of resin, metal, glass, ceramic, or a combination of these materials depending on the purpose.

[0044] The shape of the channel plate 31 is not particularly limited, but a flat plate shape is preferable to ensure a more uniform laminar flow of the gas mixture 33. In this case, the length of the slit-shaped outlet 35a in the direction parallel to the longitudinal direction can be set to a sufficient length to match the shape of the substrate, and is preferably equal to or greater than the longitudinal length of the outlet 35a. The length of the gas mixture 33 in the flow direction (referred to as the channel length) may be appropriately set depending on various film formation conditions, including the physical properties of the raw material solution 21. For example, if the raw material mist 22 is prone to evaporation, i.e., if the mist lifespan is short, shortening the channel length can more effectively prevent powder adhesion. If the mist lifespan is long, extending the channel length can increase the raw material yield.

[0045] Furthermore, the channel plate 31 is not particularly limited as long as it is sufficiently stable against the raw material solution 21 used and the temperature at which it is used, and can be made of resin, metal, glass, ceramic, or a combination of these materials depending on the purpose.

[0046] The form of the exhaust means 36 is not particularly limited, and a wide variety of known exhaust means can be applied, but it is preferable that the exhaust port 36a has an opening with a length equal to or greater than the length of the channel plate 31 in the direction perpendicular to the gas flow. This makes it possible to maintain a good flow of the gas mixture 33. Furthermore, the exhaust means 36 is not particularly limited as long as it is sufficiently stable with respect to the raw material solution 21 used and the operating temperature, and can be made of resin, metal, glass, or a combination of these materials depending on the purpose.

[0047] The exhaust volume of the exhaust means 36 may be adjusted appropriately depending on the film formation conditions. To maintain a laminar flow of the gas-air mixture 33, the exhaust volume is preferably set to approximately 70 to 250%, more preferably approximately 80 to 200%, of the flow rate of the gas-air mixture 33. When the exhaust volume is small relative to the flow rate of the gas-air mixture 33, the gas-air mixture 33 is directly exhausted to the exhaust means side. In this case, the gas-air mixture 33 may be exhausted to the outside of the apparatus, for example, by a housing exhaust provided in a housing containing the film formation unit 30 (not shown). When the exhaust volume is large relative to the flow rate of the gas-air mixture 33, the difference in the amount of air flows in from the gas-air mixture supply means 35 side together with the gas-air mixture 33. In either case, the flow of the gas-air mixture 33 flowing within the space 39 is maintained without disturbance.

[0048] The gas mixture supply means 35 and the channel plate 31 are equipped with temperature adjustment units 35b and 31b, which are connected to a temperature control unit 37. The temperature T1 of the gas mixture supply means 35 and the temperature T2 of the channel plate 31 are controlled to predetermined temperatures by the temperature control unit 37 via the temperature adjustment units 35b and 31b.

[0049] Although there are no particular limitations on the measurements of T1 and T2, they can each be measured values ​​on the outer surfaces, and it is preferable that the temperature T2 of the channel plate 31 be the temperature of the surface in contact with the gas mixture 33. For example, when film formation involves heating the substrate 34, it is preferable to perform the measurements at locations on the gas mixture supply means 35 and the channel plate 31 that are close to the heat source of the heating means. The measurements can be performed by known temperature measurement methods, such as a thermocouple or a radiation thermometer.

[0050] (Temperature conditions) The temperatures T1 and T2 are appropriately set and controlled taking into consideration various conditions such as the temperature and physical properties (mainly vapor pressure) of the raw solution 21 or the solvent used in the raw solution 21, the supply amount of the gas mixture 33, the mist concentration in the gas mixture 33, and the linear velocity between the channel plate 31 and the substrate 34. For example, under general conditions when water is used as the solvent, it is preferable to set the temperatures to 35°C to 150°C.

[0051] That is, the appropriate setting ranges for temperatures T1 and T2 are primarily related to the amount of heat received by the gas mixture 33 after it is introduced into the gas mixture supply means 35. For example, if the amount of heat in the system extending from the gas mixture supply means 35 to the exhaust means 36 is too low relative to the mist concentration and temperature of the gas mixture 33, the raw material mist 22 will condense in the system, preventing normal film formation. Furthermore, the condensation will fall onto the substrate, causing defects. Conversely, if the amount of heat in the system is too high, excessive evaporation of the solvent in the raw material solution 21 will result in much of the raw material being consumed as powder, not only slowing the film growth rate but also causing the powder to adhere to the film, introducing defects into the film and degrading film quality. In some cases, the increase in mist temperature will increase the concentration of solid components in the mist, potentially triggering undesirable chemical reactions and resulting in abnormalities in the intended film formation. For example, when α-phase gallium oxide is epitaxially grown on a sapphire substrate, if the temperature of the mist rises excessively as described above, abnormally grown grains may be formed or a crystal phase transition may occur.

[0052] The abnormally grown grains are mainly amorphous or crystalline fine grains that grow on deposits derived from the solid content of the mist, and are often submicron to 1 μm in diameter. Furthermore, the crystalline phase transitions involved here result in the appearance of different crystalline polymorphs, specifically β, γ, ε, and δ phases, despite the same composition as the growing film. These crystalline phase transitions vary in shape and size depending on the crystalline phase, but typically occur as islands of 1 to 5 μm in size. These abnormally grown grains themselves act as sources of dislocations, reducing film quality. Furthermore, as film growth progresses and these foreign particles are incorporated into the film, stress is generated between the growing film and the grains, causing cracks in the film and significantly reducing film quality. These foreign substances can be detected by known methods such as optical microscopy and light scattering.

[0053] (Control method) Temperature control unit 37 measures T1 and T2, or temperature T1' of temperature adjustment unit 35b and temperature T2' of temperature adjustment unit 31b, and directly or indirectly controls T1 and T2 via temperature adjustment units 35b and 31b so as to eliminate deviations between the measured values ​​and the set values ​​(reference values) of T1 and T2. Control of T1 and T2 using T1' and T2' is possible, for example, by measuring the correlation between T1 and T2 under predetermined film formation conditions and T1' and T2' at that time.

[0054] The method for calculating the deviation is not particularly limited, and any known method can be used. The temperature control method is also not particularly limited, and any known method such as on-off control, PID control, or cascade control can be used.

[0055] The structure of the stage 32 is not particularly limited, and it need only be stable enough depending on the characteristics of the raw materials used and the temperature conditions. In this case, metals such as aluminum and stainless steel may be used, but when film formation is performed at a higher temperature than the heat resistance temperature of these metals or when an acidic or alkaline raw material is used, alloys such as Hastelloy, soda-lime glass, borosilicate glass, quartz, silicon carbide, or ceramics such as silicon nitride and aluminum nitride may also be used.

[0056] Although not shown, the film forming unit 30 may further include a known heating means such as a resistance heater or a lamp heater for heating the substrate 34. In this case, the heater may be built into the stage 32, for example, or may be installed outside the stage 32. The stage 32 may also include a mechanism for holding the substrate 34. In this case, known substrate holding methods such as a vacuum chuck, a mechanical clamp, or an electrostatic chuck can be used.

[0057] The substrate 34 is not particularly limited as long as it can support the film to be formed. The material of the substrate 34 is also not particularly limited and may be a known material, an organic compound, or an inorganic element or compound. Examples of the material include, but are not limited to, polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluororesin, metals such as iron, aluminum, stainless steel, and gold, silicon, sapphire, quartz, glass, calcium carbonate, lithium tantalate, lithium niobate, gallium oxide, SiC, ZnO, and GaN. The substrate may have any shape, such as a plate-like shape (e.g., a flat plate or disc), a fiber-like shape, a rod-like shape, a cylindrical shape, a prismatic shape, a cylindrical shape, a spiral shape, a spherical shape, or a ring-like shape. In particular, when the substrate is a plate-like substrate, the substrate is preferably, but not limited to, a shape with an area of ​​5 cm or less. 2 More than 10cm, preferably 2 A substrate having the above thickness and a thickness of 50 to 2000 μm, more preferably 100 to 800 μm, can be suitably used.

[0058] Furthermore, in the film deposition method of the present invention, the substrate 34 and the channel plate 31 may be opposed to each other and kept stationary at a predetermined position while film deposition is performed, or a moving means (not shown) or a rotating means (not shown) may be provided to change the relative position of the substrate 34 in the horizontal direction. By providing a moving means or a rotating means, the thickness distribution of the formed film can be improved, and film deposition on a substrate with a large diameter or a long length becomes possible.

[0059] The moving means may be a mechanism for reciprocating in a horizontal uniaxial direction. For example, when moving in a direction parallel to the mist flow direction, the moving speed may be adjusted appropriately depending on the purpose, but is preferably 0.1 mm / s to 100 mm / s, and more preferably 1 mm / s to 30 mm / s. A speed of 1 mm / s or more prevents film formation from becoming reaction-rate-limiting, achieves a sufficient yield of raw materials, and reduces the chance of abnormal reactions. A speed of 100 mm / s or less allows the gas mixture 33 to sufficiently follow the moving motion, achieving an excellent film thickness distribution. Furthermore, the rotation speed when rotating is not particularly limited as long as it does not cause turbulence in the gas mixture 33, but is generally preferably 1° per second to 180° per second.

[0060] In the embodiment shown in FIG. 1, the channel plate 31 is placed above the stage 32, and the film is formed with the film forming surface of the substrate 34 facing upward. However, the film forming apparatus used in the film forming method of the present invention is not limited to this, and the channel plate 31 may be placed below the stage 32, and the film may be formed with the film forming surface of the substrate 34 facing downward.

[0061] While FIG. 1 shows an example of a configuration for controlling the temperatures of the gas mixture supply means 35 and the channel plate 31, the present invention is not limited to this configuration. Furthermore, a temperature adjustment unit 36b may also be provided in the exhaust means 36, and the temperature T3 of the exhaust means 36 may be controlled by connecting it to a temperature control unit 37. In this case, T3 can be controlled in the same manner as T1 and T2 described above. Furthermore, temperature T3 is appropriately set and controlled based on various conditions, such as the temperature and physical properties (mainly vapor pressure) of the raw material solution 21 or the solvent used in the raw material solution 21, the supply amount of the gas mixture 33, the mist concentration in the gas mixture 33, and the linear velocity between the channel plate 31 and the substrate 34. For example, under typical conditions when water is used as the solvent, a temperature between 35°C and 150°C is preferable. If T3 is equal to or higher than a certain temperature, the raw material mist 22 does not condense in the exhaust means 36 and does not fall onto the substrate 34, forming defects. Furthermore, if T3 is below a certain temperature, the solid content of the raw material mist 22 does not precipitate in the exhaust means 36, so the exhaust port does not become clogged, allowing for normal film formation, and the precipitates do not fall onto the substrate 34 and form defects. By controlling T3 in this way, the gas-air mixture can be discharged more efficiently, allowing for more stable production of high-quality films.

[0062] Next, the configuration of the film forming section 30 according to the present invention will be described in more detail with reference to FIGS.

[0063] 2, a channel plate 31 is arranged parallel to a stage 32, and a gas mixture supply means 35 and an exhaust means 36 are arranged across the channel plate 31 so that a mist outlet 35a of the gas mixture supply means 35 faces an exhaust outlet 36a of the exhaust means 36. The gas mixture supply means 35, channel plate 31, and exhaust means 36 are equipped with temperature control units 35b, 31b, and 36b, respectively, and are connected in series by a temperature control unit 37 and a connection unit 38. Reference numeral 33 denotes a gas mixture, and 34 denotes a substrate.

[0064] The arrangement and configuration of the temperature control units 35b, 31b, and 36b may be adjusted as appropriate depending on the shapes and configurations of the gas-air mixture supply means 35, the channel plate 31, and the exhaust means 36. Furthermore, the temperature control units 35b, 31b, and 36b may perform heat exchange using a liquid or gaseous heat medium, or may utilize the Peltier effect. A wide variety of known heat mediums can be used as the heat medium, and suitable heat mediums include liquids such as water, glycols, alcohols, and silicone oils, and gases such as air, helium, and fluorocarbons. The connection unit 38 may be electrical wiring or piping suitable for the heat medium, depending on the configuration of the temperature control units 35b, 31b, and 36b.

[0065] The distance h between the channel plate 31 and the main surface of the substrate 34 is adjusted as appropriate depending on factors such as the amount of gas-air mixture 33 supplied, but is generally set to between 1 mm and 40 mm. If the distance is 1 mm or more, the film thickness distribution tends to be small, and if the distance is 40 mm or less, the amount of gas-air mixture supplied to the substrate 34 increases, improving productivity and increasing the raw material yield, resulting in lower costs.

[0066] 2, temperature adjustment units 35b, 31b, and 36b are connected in series to temperature control unit 37, but the present invention is not limited to this, and as shown in Fig. 3, temperature control units 371, 372, and 373 may be provided individually for gas mixture supply means 35, channel plate 31, and exhaust means 36, respectively, to adjust temperature adjustment units 35b, 31b, and 36b individually. Note that 32 is a stage, 34 is a base, and 381, 382, ​​and 383 are connecting units.

[0067] In the example shown in Figures 1, 2 and 3, the air-fuel mixture supply means 35, the channel plate 31 and the exhaust means 36 are arranged separately, but the present invention is not limited to this, and some or all of the air-fuel mixture supply means 35, the channel plate 31 and the exhaust means 36 may be configured as an integrated unit.

[0068] In the laminate of the present invention, the density of foreign particles with a diameter of 0.3 μm or more on the crystal film surface is 1 cm -2The lower limit is not particularly limited, but for example, 0.1 cm -2 It can be more than that.

[0069] The thickness of the crystal film is preferably 0.3 μm or more, and although there is no particular upper limit, it can be, for example, 100 μm or less.

[0070] [Film forming method] The present invention includes the steps of: atomizing a raw material solution to form a raw material mist; mixing the raw material mist with a carrier gas to form a mixture; placing a substrate on a stage; a film-forming step of supplying the gas mixture from a gas mixture supply means to the substrate and forming a film on the substrate by a thermal reaction; an exhaust step of exhausting the gas mixture after the film formation by an exhaust means; A film forming method comprising: a channel plate is disposed on the base body so as to face the base body with a space therebetween; forming a mixed gas flow that flows linearly from the mixed gas supply means toward the exhaust means in the space above the base so that the mixed gas flows along at least a part of the main surface of the base; The present invention provides a film formation method in which at least the temperature T1 of the gas mixture supply means and the temperature T2 of the channel plate are controlled in the film formation step and the exhaust step.

[0071] This type of film formation method suppresses deterioration of the raw material mist and generation of powder, thereby suppressing the formation of defects and maintaining a good raw material yield, making it a film formation method that can stably produce high-quality films on the surfaces of large-diameter substrates.

[0072] Furthermore, the temperature T3 of the exhaust means can be controlled. With such a film formation method, the air-fuel mixture can be discharged more efficiently, resulting in a film formation method that can more stably produce high-quality films. [Example]

[0073] EXAMPLES The present invention will be specifically explained below using examples and comparative examples, but the present invention is not limited to these.

[0074] Example 1 In the film formation apparatus of FIG. 1, an α-gallium oxide film was formed using the film formation section of FIG. As a raw material solution, gallium acetylacetonate was dissolved at a rate of 0.02 mol / L in a dilute hydrochloric acid solution to which 34% hydrochloric acid was added at a volume ratio of 1%, and this was filled into an atomization device (atomization means). Next, ultrasonic vibrations were propagated to the raw material solution in the atomization device through the water by an ultrasonic vibration plate, thereby atomizing (misting) the raw material solution. Next, a c-plane single crystal sapphire wafer with a thickness of 0.35 mm and a diameter of 4 inches (approximately 10 cm) was placed on the stage and heated to a substrate temperature of 450°C. The air-fuel mixture supply means and exhaust means used nozzles made of aluminum with anodized aluminum surfaces, and the channel plate was also made of aluminum with anodized aluminum surfaces. Water was circulated by a chiller as a heat medium in the temperature control parts of these nozzles and channel plates, and the temperature at the bottom of each part was maintained at 60°C. A gas cylinder filled with nitrogen gas was used to supply the carrier gas. The gas cylinder and the atomizer were connected with a urethane resin tube, and the atomizer and nozzle unit were further connected with a quartz pipe. Next, nitrogen gas was added to the source container at a flow rate of 20 L / min, and a mixture of mist and nitrogen gas was supplied to the nozzle unit. The exhaust flow rate was set to 25 L / min, and the stage was moved horizontally while maintaining the distance between the channel plate and the substrate surface at 3 mm, and film formation was carried out for 20 minutes. Immediately after this, the supply of nitrogen gas was stopped, and the supply of the air-fuel mixture to the nozzle unit was stopped. The prepared film was confirmed to be α-phase Ga2O3 by X-ray diffraction measurement. The thickness of the film was then measured at nine points on the surface in a cross direction from the center of the substrate using ellipsometry analysis, and the average value was calculated. In addition, the density of foreign particles (diameter 0.3 μm or more) in the area excluding a 5 mm periphery of the film formation surface was evaluated using a substrate inspection machine (KLA candela-CS10).

[0075] Example 2 Film formation was carried out in the same manner as in Example 1, except that the temperatures at the mixture supply nozzle and the bottom of the channel plate were kept at 60° C. and the temperature of the exhaust nozzle was not adjusted (no circulating water was flowed). The prepared film was confirmed to be α-phase Ga2O3 by X-ray diffraction measurement. The thickness of the film was then measured at nine points on the surface by ellipsometry, and the average value was calculated. The density of foreign particles (diameter 0.3 μm or more) in the area excluding a 5 mm periphery of the film formation surface was evaluated using a substrate inspection machine (KLA candela-CS10).

[0076] (Comparative Example 1) Film formation was carried out in the same manner as in Example 1, except that the temperature at the bottom of the mixture supply nozzle was kept at 60° C. and a film formation apparatus not equipped with temperature control means for the channel plate and exhaust nozzle was used. The prepared film was confirmed to be α-phase Ga2O3 by X-ray diffraction measurement. The thickness of the film was then measured at nine points on the surface by ellipsometry, and the average value was calculated. The density of foreign particles (diameter 0.3 μm or more) in the area excluding a 5 mm periphery of the film formation surface was evaluated using a substrate inspection machine (KLA candela-CS10).

[0077] (Comparative Example 2) Film formation was carried out in the same manner as in Example 1, except that a film formation apparatus was used that was not equipped with any temperature control means for the mixture supply nozzle, the channel plate, and the exhaust nozzle. X-ray diffraction measurements confirmed that the prepared film contained α-phase Ga2O3, but also a small amount of ε-phase. The thickness of the film was then measured at nine points on the surface by ellipsometry, and the average value was calculated. The density of foreign particles (diameter 0.3 μm or more) in the area excluding a 5 mm periphery of the film formation surface was evaluated using a substrate inspection machine (KLA candela-CS10).

[0078] Example 3 In the film forming apparatus of FIG. 1, a film of hafnium oxide was formed using the film forming section of FIG. The raw material solution was prepared by dissolving acetylacetonatohafnium(IV) in ethanol at a ratio of 0.02 mol / L, and this was filled into an atomization device equipped with two ultrasonic vibration plates (frequency 2.4 MHz). Next, ultrasonic vibrations were propagated to the raw material solution in the atomization device through the water by an ultrasonic vibration plate, thereby atomizing (misting) the raw material solution. Next, a single-crystal silicon wafer with a thickness of 0.35 mm and a diameter of 4 inches (approximately 10 cm) was placed on a SiC stage equipped with a resistance heater and heated to 400°C. The air-fuel mixture supply means and exhaust means used nozzles made of aluminum with anodized aluminum surfaces, and the channel plates were similarly made of aluminum with anodized aluminum surfaces. An ethylene glycol-based circulating liquid was circulated by a chiller as a heat medium in the temperature control parts of these nozzles and channel plates, and the temperature at the bottom of each part was maintained at 20°C. A gas cylinder filled with nitrogen gas was used to supply the carrier gas. The gas cylinder and the atomizer were connected with a urethane resin tube, and the atomizer and nozzle unit were further connected with a quartz pipe. Next, nitrogen gas was added to the source container at a flow rate of 20 L / min, and a mixture of mist and nitrogen gas was supplied to the nozzle unit. The exhaust flow rate was set to 25 L / min, and the stage was moved horizontally while maintaining the distance between the channel plate and the substrate surface at 3 mm, and film formation was carried out for 20 minutes. Immediately after this, the supply of nitrogen gas was stopped, and the supply of the air-fuel mixture to the nozzle unit was stopped. The prepared film was confirmed to be HfO2 by XPS measurement and ellipsometry analysis. The thickness of the film was then measured at nine points on the surface by ellipsometry, and the average value was calculated. The density of foreign particles (diameter 0.3 μm or more) in the area excluding a 5 mm periphery of the film formation surface was evaluated using a substrate inspection machine (KLA candela-CS10).

[0079] (Comparative Example 3) Film formation was carried out in the same manner as in Example 3, except that a film formation apparatus was used that was not equipped with any temperature control means for the mixture supply nozzle, the channel plate, and the exhaust nozzle. After this, XPS measurement was carried out and it was found that no film was formed on the substrate. Thereafter, film thickness and foreign matter were measured in the same manner as in Example 1.

[0080] Example 4 In the film formation apparatus of FIG. 1, a silicon oxide film was formed using the film formation unit of FIG. The raw material solution was prepared by dissolving polysilazane in ethylene glycol at a ratio of 0.02 mol / L and further adding 5% by volume of hydrogen peroxide water, and this was filled into an atomization device equipped with two ultrasonic vibration plates (frequency 2.4 MHz). Next, ultrasonic vibrations were propagated to the raw material solution in the atomization device through the water by an ultrasonic vibration plate, thereby atomizing (misting) the raw material solution. Next, a single-crystal silicon wafer with a thickness of 0.35 mm and a diameter of 4 inches (approximately 10 cm) was placed on a SiC stage equipped with a resistance heater and heated to 250°C. The air-fuel mixture supply means and exhaust means used nozzles made of aluminum with anodized aluminum surfaces, and the channel plate was also made of aluminum with anodized aluminum surfaces. Water was circulated by a chiller as a heat medium in the temperature control parts of these nozzles and channel plates, and the temperature at the bottom of each part was maintained at 35°C. A gas cylinder filled with nitrogen gas was used to supply the carrier gas. The gas cylinder and the atomizer were connected with a urethane resin tube, and the atomizer and nozzle unit were further connected with a quartz pipe. Next, nitrogen gas was added to the source container at a flow rate of 20 L / min, and a mixture of mist and nitrogen gas was supplied to the nozzle unit, and the exhaust flow rate was set to 25 L / min. During this time, the stage was moved horizontally while maintaining the distance between the channel plate and the substrate surface at 3 mm, and film formation was carried out for 5 minutes. Immediately after this, the supply of nitrogen gas was stopped, and the supply of the air-fuel mixture to the nozzle unit was stopped. The infrared absorption spectrum of the prepared film revealed that it was SiO2. The thickness of the film was then measured at nine points on the surface by ellipsometry, and the average value was calculated. The density of foreign particles (diameter 0.3 μm or more) in the area excluding a 5 mm periphery of the film formation surface was evaluated using a substrate inspection machine (KLA candela-CS10).

[0081] Comparative Example 4 Film formation was carried out in the same manner as in Example 4, except that a film formation apparatus was used that was not equipped with any temperature control means for the mixture supply nozzle, the channel plate, and the exhaust nozzle. Thereafter, the film was evaluated in the same manner as in Example 4. The infrared absorption spectrum of the prepared film revealed that it was SiO2. Thereafter, film thickness measurement and foreign matter measurement were carried out in the same manner as in Example 1.

[0082] [Table 1]

[0083] Table 1 shows the evaluation results of Examples 1, 2, 3, and 4 and Comparative Examples 1, 2, 3, and 4. The film produced by the film-forming method of the present invention exhibited stable film growth and a low foreign matter density. In contrast, the film formed by the conventional method exhibited a decreased film thickness and a clearly increased foreign matter density. This is thought to be due to the excessive heating of the raw material mist, which promoted the precipitation of solids in the mist, resulting in the preferential formation of powder and a decrease in the film-forming yield.

[0084] From the above results, it was found that the present invention can provide a film forming apparatus capable of producing higher quality films with higher productivity than conventional techniques.

[0085] The present specification includes the following aspects. [1]: A step of atomizing a raw material solution to form a raw material mist; mixing the raw material mist with a carrier gas to form a mixture; placing a substrate on a stage; a film-forming step of supplying the gas mixture from a gas mixture supply means to the substrate and forming a film on the substrate by a thermal reaction; an exhaust step of exhausting the gas mixture after the film formation by an exhaust means; A film forming method comprising: a channel plate is disposed on the base body so as to face the base body with a space therebetween; forming a mixed gas flow that flows linearly from the mixed gas supply means toward the exhaust means in the space above the base so that the mixed gas flows along at least a part of the main surface of the base; In the film forming step and the exhaust step, at least the temperature T1 of the gas mixture supply means and the temperature T2 of the channel plate are controlled. A film forming method characterized by: [2]: The film forming method according to [1] above, further comprising controlling the temperature T3 of the exhaust means. [3]: A step of atomizing the raw material solution to form a raw material mist; mixing the raw material mist with a carrier gas to form a mixture; placing a substrate on a stage; a film-forming step of supplying the gas mixture from a gas mixture supply means to the substrate and forming a film on the substrate by a thermal reaction; an exhaust step of exhausting the gas mixture after the film formation by an exhaust means; A film forming method comprising: a channel plate is disposed on the base body so as to face the base body with a space therebetween; forming a mixed gas flow that flows linearly from the mixed gas supply means toward the exhaust means in the space above the base so that the mixed gas flows along at least a part of the main surface of the base; In the film forming step and the exhaust step, at least the temperature T2 of the channel plate is controlled. A film forming method characterized by: [4]: The film forming method according to [3] above, further comprising controlling the temperature T3 of the exhaust means. [5]: Atomization means for atomizing the raw material solution to form raw material mist; a carrier gas supply means for transporting the raw material mist; a gas mixture supply means for supplying a gas mixture obtained by mixing the raw material mist and the carrier gas to a substrate surface; a stage on which the substrate is placed; an exhaust means for exhausting the air-fuel mixture; a channel plate disposed on the base body so as to face the base body with a space therebetween; The apparatus is provided with temperature control means for controlling at least the temperature T1 of the air-fuel mixture supply means and the temperature T2 of the channel plate. A film forming apparatus characterized by: [6]: The film forming apparatus according to [5], further comprising a temperature control means for controlling the temperature T3 of the exhaust means. [7]: A crystalline substrate; an epitaxially grown crystal film formed on the crystal substrate; A laminate comprising: The density of foreign particles with a diameter of 0.3 μm or more on the surface of the crystal film is 1 cm -2 is A laminate characterized by: [8]: The laminate according to the above [7], wherein the thickness of the crystal film is 0.3 μm or more.

[0086] The present invention is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits similar effects is included within the technical scope of the present invention.

Claims

1. atomizing the raw material solution to form a raw material mist; mixing the raw material mist with a carrier gas to form a mixture; placing a substrate on a stage; a film-forming step of supplying the gas mixture from a gas mixture supply means to the substrate and forming a film on the substrate by a thermal reaction; an exhaust step of exhausting the gas mixture after the film formation by an exhaust means; A film forming method comprising: a channel plate is disposed on the base body so as to face the base body with a space therebetween; forming a mixed gas flow in the space above the base such that the mixed gas flows linearly from the mixed gas supply means toward the exhaust means along the entire main surface of the base; In the film forming step and the exhaust step, at least the temperature T1 of the air-fuel mixture supply means and the temperature T2 of the channel plate are controlled. A film forming method characterized by:

2. 2. The film forming method according to claim 1, further comprising controlling a temperature T3 of said exhaust means.

3. atomizing the raw material solution to form a raw material mist; mixing the raw material mist with a carrier gas to form a mixture; placing a substrate on a stage; a film-forming step of supplying the gas mixture from a gas mixture supply means to the substrate and forming a film on the substrate by a thermal reaction; an exhaust step of exhausting the gas mixture after the film formation by an exhaust means; A film forming method comprising: a channel plate is disposed on the base body so as to face the base body with a space therebetween; forming a mixed gas flow in the space above the base such that the mixed gas flows linearly from the mixed gas supply means toward the exhaust means along the entire main surface of the base; In the film forming step and the exhaust step, at least the temperature T2 of the channel plate is controlled. A film forming method characterized by:

4. 4. The film forming method according to claim 3, further comprising controlling a temperature T3 of said exhaust means.

5. an atomization means for atomizing the raw material solution to form a raw material mist; a carrier gas supply means for transporting the raw material mist; a gas mixture supply means for supplying a gas mixture obtained by mixing the raw material mist and the carrier gas to a substrate surface; a stage on which the substrate is placed; an exhaust means for exhausting the air-fuel mixture; a channel plate disposed on the base body so as to face the base body with a space therebetween; The apparatus includes temperature control means for controlling at least a temperature T1 of the air-fuel mixture supply means and a temperature T2 of the channel plate, The gas mixture flows linearly through the space above the substrate from the gas mixture supply means to the exhaust means along the entire main surface of the substrate. A film forming apparatus characterized by:

6. 6. The film forming apparatus according to claim 5, further comprising a temperature control means for controlling a temperature T3 of the exhaust means.

7. a crystalline substrate; an epitaxially grown crystal film formed on the crystal substrate; A laminate comprising: The density of foreign particles having a diameter of 0.3 μm or more on the surface of the crystal film is 1 cm －２ is as follows: The crystalline film is α-gallium oxide or hafnium oxide. A laminate characterized by:

8. 8. The laminate according to claim 7, wherein the crystal film has a thickness of 0.3 μm or more.

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