Film forming apparatus, film forming method, and laminate

Abstract

The present invention provides a film forming device which is provided with: an atomization unit which generates a mist by atomizing a starting material solution; a carrier gas supply unit which supplies a carrier gas that carries the mist, which has been generated in the atomization unit; and a film forming unit which forms a film by subjecting the mist, which has been carried thereto by the carrier gas, to a heat treatment. With respect to this film forming device, the film forming unit is provided with: a substrate stage part on which a substrate is placed; a nozzle which is arranged above the substrate stage part and supplies the mist onto the substrate; a top plate which is arranged above the substrate stage part and rectifies the mist supplied from the nozzle; and side walls which are arranged so as to face each other with the substrate stage part being interposed therebetween. If I (cm) is the height difference between a substrate stage surface of the substrate stage part and the bottom surface of the top plate and J (cm) is the shortest distance between a substrate stage region of the substrate stage part and the side walls, IJ ≤ 15 is satisfied. Consequently, the present invention provides a film forming device which is capable of forming a large-area film that has excellent in-plane uniformity of the film thickness distribution.

Description

[Technical Field]

[0001] The present invention relates to a film formation apparatus, a film formation method, an oxide semiconductor film, and a laminate. [Background technology]

[0002] High-vacuum deposition equipment capable of realizing non-equilibrium conditions, such as pulsed laser deposition (PLD), molecular beam epitaxy (MBE), and sputtering, has been developed, enabling the fabrication of oxide semiconductors that were previously impossible using melt deposition and other methods. Furthermore, mist chemical vapor deposition (Mist CVD), which uses atomized raw materials to grow crystals on a substrate, has been developed, enabling the fabrication of corundum-structured gallium oxide (α-Ga2O3). As a wide-bandgap semiconductor, α-Ga2O3 is expected to be applied to next-generation switching devices, achieving high voltage resistance, low loss, and high heat resistance.

[0003] Regarding the mist CVD method, Patent Document 1 describes a tubular furnace type mist CVD apparatus. Patent Document 2 describes a fine channel type mist CVD apparatus. Patent Document 3 describes a linear source type mist CVD apparatus. Patent Document 4 describes a tubular furnace mist CVD apparatus, which differs from the mist CVD apparatus described in Patent Document 1 in that a carrier gas is introduced into the mist generator. Patent Document 5 describes a mist CVD apparatus in which a substrate is placed above a mist generator and rotated. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 1-257337 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-307238 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-46772 [Patent Document 4] Patent No. 5397794 [Patent Document 5] International Publication No. 2020-261355 Summary of the Invention [Problem to be solved by the invention]

[0005] Unlike other CVD methods, the mist CVD method allows for film deposition at relatively low temperatures and can also produce metastable crystal structures such as the corundum structure of α-Ga2O3. However, the inventors discovered that when mist is supplied from above the substrate, thermal convection and mixing of the mist-containing gas with the ambient gas can disrupt the mist flow, making it difficult to maintain in-plane uniformity in the thickness distribution of the deposited film. Semiconductor films with low in-plane uniformity can result in reduced yields when semiconductor devices are fabricated and can increase the number of semiconductor device fabrication steps, such as polishing.

[0006] Patent Document 5 discloses an example in which mist is supplied to a substrate placed above a mist generator while the substrate is rotating, thereby forming a semiconductor film with good in-plane film thickness distribution. However, according to the examples in this document, when a film is formed on a 4-inch (100 mm diameter) substrate, the minimum film thickness / maximum film thickness ratio is 55.0%, which does not result in a film with excellent in-plane uniformity of film thickness distribution. Furthermore, when the present inventors performed film formation based on Patent Document 5, the film formation apparatus in this document only produced a film that was thick in the center and had poor in-plane uniformity of film thickness distribution. Furthermore, when a film was formed on a 6-inch (150 mm diameter) substrate, it was found that the in-plane uniformity of film thickness distribution was even worse.

[0007] The present invention has been made to solve the above problems, and an object of the present invention is to provide a large-area oxide semiconductor film having excellent in-plane uniformity in film thickness distribution, a stack including such a film, and a film formation apparatus and film formation method capable of forming a large-area film having excellent in-plane uniformity in film thickness distribution. [Means for solving the problem]

[0008] The present invention has been made to achieve the above-mentioned object, and provides a film formation apparatus comprising: a mist-forming section that generates mist by turning a raw material solution into mist; a carrier gas supply section that supplies a carrier gas that transports the mist generated in the mist-forming section; and a film formation section that heat-treats the mist transported by the carrier gas to form a film, wherein the film formation section comprises a substrate mounting section on which the substrate is placed; a nozzle located above the substrate mounting section that supplies the mist onto the substrate; a top plate located above the substrate mounting section that rectifies the mist supplied from the nozzle; and side walls that are provided opposite to each other and sandwich the substrate mounting section, wherein when the difference in height between the substrate mounting surface of the substrate mounting section and the bottom surface of the top plate is I [cm] and the shortest distance between the substrate mounting area of ​​the substrate mounting section and the side wall is J [cm], IJ≦15 is provided as the film formation apparatus.

[0009] This film formation apparatus has a simple structure and is capable of forming a film with good in-plane uniformity of film thickness distribution on a substrate using a mist-like raw material solution. The synergistic effect of the flow straightening effect of the top plate and the flow straightening effect of the sidewalls generates a uniform gas flow above and along the substrate (parallel to the substrate surface), making it possible to produce a uniform film on the substrate.

[0010] In this case, the film forming apparatus may be one in which the bottom surface of the top plate, the nozzle opening surface, and the substrate mounting surface are all parallel to one another.

[0011] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0012] In this case, the film forming apparatus can be one in which I [cm] is 0.15 cm or more and 6.05 cm or less.

[0013] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0014] In this case, the film forming apparatus can have J [cm] of 5.0 cm or less.

[0015] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0016] At this time, the area of ​​the bottom surface of the top plate is B [cm 2 ], the film forming apparatus can satisfy B≧40.

[0017] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0018] At this time, the area of ​​the substrate to be processed is defined as A [cm 2 ], the area of ​​the bottom surface of the top plate is B [cm 2 ], the film forming apparatus can satisfy B / A≧0.5.

[0019] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0020] At this time, the area of ​​the surface of the side wall on the substrate placement portion side is defined as C [cm 2 ], the film forming apparatus can satisfy C≧20.

[0021] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0022] At this time, the area of ​​the substrate to be processed is defined as A [cm 2 ], and the area of ​​the opposing surfaces of the side walls is C [cm 2 ], the film forming apparatus can satisfy C / A≧0.2.

[0023] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0024] In this case, the film forming apparatus may further include an exhaust section for exhausting exhaust gas from the film forming section.

[0025] This makes it possible to form a film with even better in-plane uniformity in film thickness distribution.

[0026] In this case, the film forming apparatus may further include a moving mechanism for moving the substrate below the nozzle.

[0027] This makes it possible to form a film with a good in-plane uniformity in film thickness distribution over a large area.

[0028] In this case, the film forming unit may be a film forming apparatus including a film forming chamber, and the side wall may be a wall of the film forming chamber.

[0029] This results in a film forming apparatus with a simpler structure.

[0030] In this case, the film formation unit may be a film formation apparatus further including a film formation chamber that houses the substrate placement unit, the nozzle, the top plate, and the side wall therein.

[0031] This makes it possible to reduce contamination by impurities.

[0032] The present invention has been made to achieve the above-mentioned object, and provides a film formation method for forming a film on a substrate by heat-treating a mist of a raw material solution, the method comprising: a mist generation process for misting the raw material solution to generate the mist; a mist transport process for transporting the mist to a film formation section; and a film formation process for supplying the mist from a nozzle provided above a substrate mounting section onto a substrate placed on the substrate mounting section in the film formation section to heat-treat and form a film, wherein in the film formation process, the mist is supplied from the nozzle into a space surrounded by a top plate provided above the substrate mounting section, the top plate having a height difference of I [cm] between the substrate mounting surface of the substrate mounting section and a bottom surface of the top plate, and side walls provided opposite to each other so as to sandwich the substrate mounting section, the shortest distance from the top plate to a substrate mounting area of ​​the substrate mounting section being J [cm], and the top plate and the side walls are arranged so that IJ≦15.

[0033] This film formation method makes it possible to form a film with good in-plane uniformity of film thickness distribution on a substrate using a mist-like raw material solution in a simple manner. The combined effect of the flow straightening effect of the top plate and the flow straightening effect of the side walls allows for a uniform gas flow above and along the substrate (parallel to the substrate surface), resulting in the formation of a uniform film on the substrate.

[0034] In this case, the top plate and the side wall can be provided so that the bottom surface of the top plate, the nozzle opening surface, and the substrate placement surface are all parallel to one another.

[0035] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0036] In this case, the top plate can be provided so that the difference I [cm] in height between the substrate placement surface of the substrate placement portion and the bottom surface of the top plate is 0.15 cm or more and 6.05 cm or less.

[0037] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0038] In this case, the side wall can be provided so that the J [cm] is 5.0 cm or less.

[0039] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0040] At this time, the area of ​​the bottom surface of the top plate is B [cm 2 ], the top plate can be provided so that B≧40.

[0041] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0042] At this time, the area of ​​the substrate to be processed is defined as A [cm 2 ], the area of ​​the bottom surface of the top plate is B [cm 2 ], the top plate can be provided so that B / A≧0.5.

[0043] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0044] At this time, the area of ​​the surface of the side wall on the substrate placement portion side is defined as C [cm 2 ], the side walls can be provided so that C≧20.

[0045] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0046] At this time, the area of ​​the substrate to be processed is defined as A [cm 2 ], and the area of ​​the opposing surfaces of the side walls is C [cm 2 ], the side wall can be provided so that C / A≧0.2.

[0047] This makes it possible to form a film with better in-plane uniformity in film thickness distribution.

[0048] In this case, the film forming method may further include an exhaust step of exhausting exhaust gas from the film forming section.

[0049] This makes it possible to form a film with even better in-plane uniformity in film thickness distribution.

[0050] In this case, when the flow rate of the carrier gas supplied from the nozzle is Q [L / min] and the flow rate of the exhaust gas is E [L / min], E / Q can be set to 5.0 or less.

[0051] This makes it possible to form a film with even better in-plane uniformity in film thickness distribution.

[0052] At this time, the substrate can be moved below the nozzle.

[0053] This makes it possible to form a film with a good in-plane uniformity in film thickness distribution over a large area.

[0054] In this case, the raw material solution may contain gallium.

[0055] This makes it possible to form a gallium oxide film with excellent in-plane uniformity in film thickness distribution.

[0056] In this case, the raw material solution may contain a halogen.

[0057] This makes it possible to form a crystalline oxide film with good in-plane uniformity in film thickness distribution.

[0058] At this time, the substrate has a surface area of ​​50 cm 2 or larger, or with a diameter of 4 inches (100 mm) or larger.

[0059] This makes it possible to form a film with a good in-plane uniformity in film thickness distribution over a large area.

[0060] The present invention has been made to achieve the above object, and provides an oxide semiconductor film containing gallium as a main component, the oxide semiconductor film having an area of ​​70 cm 2 or more, or the surface size is 4 inches (100 mm) or more in diameter, and the in-plane film thickness distribution of the oxide semiconductor film is less than ±5%.

[0061] Such an oxide semiconductor film can be suitably used for a semiconductor device because it can improve the yield when the semiconductor device is manufactured and can reduce the number of steps for manufacturing the semiconductor device, such as a polishing step.

[0062] In this case, the oxide semiconductor film can be an oxide semiconductor film having a corundum structure.

[0063] This makes it more suitable for semiconductor devices.

[0064] The present invention has been made to achieve the above object, and provides a laminate of an oxide semiconductor film containing gallium as a main component and a substrate, wherein the oxide semiconductor film of the laminate has an area of ​​70 cm 2 Alternatively, the present invention provides a laminate having a surface size of 4 inches (100 mm) or more in diameter, and wherein the in-plane film thickness distribution of the oxide semiconductor film is less than ±5%.

[0065] Such a laminate can be suitably used in semiconductor devices, for example, it can provide a good yield when manufacturing semiconductor devices and can reduce the number of semiconductor device manufacturing steps such as polishing steps.

[0066] In this case, the oxide semiconductor film can be a laminate having a corundum structure.

[0067] This makes it more suitable for semiconductor devices. [Effects of the Invention]

[0068] As described above, the film formation apparatus of the present invention is a film formation apparatus with a simple structure that is capable of forming a film with good in-plane uniformity in film thickness distribution on a substrate using a mist-like precursor solution. Furthermore, the film formation method of the present invention is a simple method that makes it possible to form a film with good in-plane uniformity in film thickness distribution on a substrate using a mist-like precursor solution. Furthermore, the oxide semiconductor film and stack of the present invention are suitable for use in semiconductor devices, as they provide a high yield when semiconductor devices are fabricated and enable a reduction in the number of semiconductor device fabrication steps, such as polishing steps. [Brief explanation of the drawings]

[0069] [Figure 1] 1 is a schematic diagram illustrating an example of a film forming apparatus according to the present invention. [Figure 2] 3A and 3B are diagrams illustrating an example of a mist generating unit according to the present invention. [Figure 3] FIG. 2 is a diagram illustrating an example of a film formation chamber according to the present invention. [Figure 4] FIG. 2 is a diagram illustrating an example of a nozzle according to the present invention. [Figure 5] FIG. 10 is a diagram illustrating an example in which a plurality of nozzles are provided. [Figure 6] FIG. 10 is a diagram illustrating an example of a nozzle having a plurality of nozzle opening surfaces. [Figure 7] FIG. 2 is a diagram illustrating an example of a film forming unit according to the present invention. [Figure 8] FIG. 2 is a diagram illustrating an example of a film forming unit according to the present invention. [Figure 9] FIG. 2 is a diagram illustrating an example of a film forming unit according to the present invention. [Figure 10] FIG. 2 is a diagram illustrating an example of a film forming unit according to the present invention. [Figure 11] FIG. 2 is a diagram illustrating an example of a film forming unit according to the present invention. [Figure 12] FIG. 2 is a diagram showing an example of a side wall according to the present invention. [Figure 13] 10A and 10B are diagrams illustrating an example of a moving mechanism that reciprocates under the nozzle. [Figure 14]10A and 10B are diagrams illustrating an example of a moving mechanism that rotates and moves under the nozzle in one direction. [Figure 15] FIG. 2 is a diagram illustrating an example of a film forming unit equipped with an exhaust unit according to the present invention. [Figure 16] 3A and 3B are diagrams illustrating an example of an exhaust unit according to the present invention. [Figure 17] FIG. 1 is a schematic diagram showing the configuration of a film forming apparatus used in Example 1 and the like. [Figure 18] 18 is a diagram showing the inside of the film formation chamber of the film formation apparatus of FIG. 17 as seen from the side of FIG. 17. [Figure 19] FIG. 1 is a schematic diagram showing the configuration of a film forming apparatus used in Example 2. [Figure 20] FIG. 1 is a schematic diagram showing the configuration of a film forming apparatus used in Comparative Example 1. [Figure 21] FIG. 10 is a schematic diagram showing the configuration of a film forming apparatus used in Comparative Example 2. [Figure 22] FIG. 10 is a schematic diagram showing the configuration of a film forming unit used in Example 6. [Figure 23] FIG. 1 is a diagram showing the results of an example and a comparative example. [Figure 24] 10 is a diagram illustrating an example of the flow of mist in the film forming section 140. FIG. [Figure 25] FIG. 25 is a diagram illustrating the inner portion of the side wall in FIG. 24. DETAILED DESCRIPTION OF THE INVENTION

[0070] The present invention will be described in detail below, but the present invention is not limited thereto.

[0071] As described above, there has been a demand for an oxide semiconductor film and a laminated body having good in-plane uniformity in film thickness distribution, as well as a film formation apparatus and a film formation method using a mist CVD method that can form such a film.

[0072] As a result of extensive research into the above-mentioned problems, the inventors have come up with a film formation apparatus including a mist generating unit that generates mist by turning a raw material solution into mist, a carrier gas supply unit that supplies a carrier gas that carries the mist generated in the mist generating unit, and a film formation unit that heat-treats the mist carried by the carrier gas to form a film, wherein the film formation unit includes a substrate placement unit on which the substrate is placed, a nozzle located above the substrate placement unit that supplies the mist onto the substrate, and a nozzle located above the substrate placement unit that supplies the mist onto the substrate. The inventors have found that a film formation apparatus having a simple structure, which is capable of forming a film with good in-plane uniformity in film thickness distribution on a substrate using a mist-like raw material solution, can be provided by a film formation apparatus comprising a top plate that rectifies the mist supplied from the nozzle and side walls that are arranged opposite to each other so as to sandwich the substrate mounting section, wherein the difference in height between the substrate mounting surface of the substrate mounting section and the bottom surface of the top plate is I [cm] and the shortest distance between the substrate mounting area of ​​the substrate mounting section and the side walls is J [cm], and IJ≦15, and thus the present invention has been completed.

[0073] As a result of extensive research into the above-mentioned problems, the present inventors have discovered a film formation method for forming a film on a substrate by heat-treating a mist of a raw material solution, the method comprising: a mist generating step of misting the raw material solution to generate mist; a mist transport step of transporting the mist to a film formation unit; and a film formation step of supplying the mist from a nozzle provided above a substrate placement unit onto a substrate placed on the substrate placement unit in the film formation unit to form a film by heat-treating the substrate; The inventors have found that a film having a good in-plane uniformity in film thickness distribution can be formed on a substrate by a simple method using a mist-like raw material solution, by a film formation method in which the mist is supplied from the nozzle into a space surrounded by a top plate having a height difference of I [cm] between the top plate and the bottom surface of the top plate, and side walls arranged opposite to each other so as to sandwich the substrate mounting section, the side walls having a shortest distance to the substrate mounting area of ​​the substrate mounting section, the space being IJ≦15, and the inventors have completed the present invention.

[0074] As a result of extensive investigation into the above-described problems, the present inventors have discovered an oxide semiconductor film containing gallium as a main component, the oxide semiconductor film having an area of ​​70 cm 2 or a laminate of an oxide semiconductor film containing gallium as a main component and a substrate, wherein the oxide semiconductor film of the laminate has an area of ​​70 cm or more, or a surface size of 4 inches (100 mm) or more in diameter and the in-plane thickness distribution of the oxide semiconductor film is less than ±5%. 2 The present inventors have also found that a stack having a surface size of 4 inches (100 mm) or more in diameter and an in-plane distribution of the thickness of the oxide semiconductor film of less than ±5% can be suitably used for semiconductor devices, for example, by improving the yield of semiconductor devices manufactured by the stack and reducing the number of semiconductor device manufacturing steps such as polishing steps.

[0075] The following description will be made with reference to the drawings.

[0076] [Oxide semiconductor film] The oxide semiconductor film according to the present invention contains gallium as a main component and has an area of ​​70 cm 2 The surface is characterized by a diameter of 4 inches (100 mm) or more, and the in-plane distribution of the film thickness is less than ±5%. The larger the film area and diameter, the larger the area that can be obtained, so there is no particular upper limit. An example of the upper limit is an area of ​​750 cm. 2 The diameter can be 100 mm or 300 mm. Generally, an oxide semiconductor film is composed of a metal and oxygen, but in the oxide semiconductor film of the present invention, the metal is mainly composed of gallium. Here, "mainly composed" means that 50 to 100% of the metal components is gallium. As the metal component other than gallium, for example, one or more metals selected from iron, indium, aluminum, vanadium, titanium, chromium, rhodium, iridium, nickel, and cobalt may be included.

[0077] The in-plane distribution of the film thickness is less than ±5%, and more preferably less than ±3%. Here, the in-plane distribution of the film thickness in the present invention is measured at nine or more points in the plane, Film thickness distribution [±%] = (maximum film thickness - minimum film thickness) / ((average film thickness) × 2) × 100 The film thickness can be measured using a step-type film thickness meter, an optical interference film thickness meter, or the like, but the measurement method is not particularly limited as long as it can measure the film thickness at each location.

[0078] The reasons why the in-plane distribution of film thickness deteriorates (increases) in conventional film formation devices and methods are thought to be non-uniformity in the amount of mist supplied due to the mist supply method, supply amount, structure around the substrate, etc., and temperature distribution on the substrate, etc. Therefore, the inventors conducted extensive research and repeated trial and error, and as a result, they came to the conclusion that by optimizing the structure around the substrate, as in the film formation device described below, the supply amount can be made uniform and the in-plane uniformity of the film thickness distribution can be improved, and they have succeeded for the first time in obtaining a film with good uniformity in the in-plane distribution of film thickness as described above.

[0079] The oxide semiconductor film according to the present invention can contain a dopant depending on the application. The dopant is not particularly limited. Examples include n-type dopants such as tin, germanium, silicon, titanium, zirconium, vanadium, and niobium, and p-type dopants such as copper, silver, tin, iridium, and rhodium. The dopant concentration is, for example, about 1.0×10 16 ~1.0×10 22 / cm 3 may be about 1.0 x 10 17 / cm 3 Even at low concentrations below 1.0 × 10 20 / cm 3 A concentration higher than this may be used.

[0080] The oxide semiconductor film according to the present invention is not particularly limited in thickness, and may be, for example, 0.05 to 100 μm, preferably 0.1 to 50 μm, and more preferably 0.5 to 20 μm.

[0081] [Laminate] The laminate of the present invention is formed on a substrate with an area of ​​70 cm 2Alternatively, the present invention is characterized in that it includes an oxide semiconductor film containing gallium as a main component and having a surface size of 4 inches (100 mm) or more in diameter.

[0082] Another layer may be interposed between the substrate and the oxide semiconductor film. The other layer has a different composition from the substrate and the outermost oxide semiconductor film, and may be, for example, a crystalline oxide film, an insulating film, a metal film, or the like.

[0083] The oxide semiconductor film and laminate according to the present invention can be used in semiconductor devices by appropriately designing the structure thereof, such as to form semiconductor layers in Schottky barrier diodes (SBDs), metal semiconductor field effect transistors (MESFETs), high electron mobility transistors (HEMTs), metal oxide semiconductor field effect transistors (MOSFETs), static induction transistors (SITs), junction field effect transistors (JFETs), insulated gate bipolar transistors (IGBTs), and light emitting diodes (LEDs).

[0084] The oxide semiconductor film and the laminate according to the present invention can be obtained by performing film formation using the film formation apparatus according to the present invention, which will be described later. The film formation apparatus and the film formation method according to the present invention will be described below.

[0085] Here, the term "mist" as used in the present invention refers to a general term for fine particles of liquid dispersed in a gas, and includes what is called fog, droplets, and the like.

[0086] [Film forming equipment] First, a film formation apparatus according to the present invention will be described. FIG. 1 shows an example of a film formation apparatus 101 according to the present invention. The film formation apparatus 101 includes at least a mist-forming unit 120 that generates mist by misting a raw material solution, a carrier gas supply unit 130 that supplies a carrier gas for transporting the mist, a film formation unit 140 that heat-treats the mist to form a film on a substrate, and a transport unit 109 that connects the mist-forming unit 120 and the film formation unit 140 and transports the mist by the carrier gas. The film formation apparatus 101 may also include an exhaust unit that exhausts exhaust gas from the film formation chamber 107. The film formation apparatus 101 may also include a control unit (not shown) that controls all or part of the film formation apparatus 101, thereby controlling its operation.

[0087] (Mist generating section) In the mist generating section 120, the raw material solution is turned into mist to generate mist. The mist generating means is not particularly limited as long as it can turn the raw material solution into mist, and any known mist generating means may be used, but it is preferable to use a mist generating means that uses ultrasonic vibrations, as this allows for more stable mist generation.

[0088] An example of such a mist-generating unit 120 is shown in FIG. 2. For example, the mist-generating unit 120 may include a mist source 104 that contains raw solution 104a, a container 105 that contains a medium capable of transmitting ultrasonic vibrations, such as water 105a, and an ultrasonic vibrator 106 attached to the bottom of the container 105. More specifically, the mist source 104, which is a container that contains the raw solution 104a, is housed in the container 105 that contains the water 105a using a support (not shown). The bottom of the container 105 is equipped with an ultrasonic vibrator 106, which is connected to an oscillator 116. When the oscillator 116 is activated, the ultrasonic vibrator 106 vibrates, and ultrasonic waves propagate through the water 105a into the mist source 104, turning the raw solution 104a into mist.

[0089] (Carrier gas supply unit) The carrier gas supply unit 130 has a carrier gas source 102a that supplies a carrier gas (main carrier gas), and may also be equipped with a flow rate control valve 103a for adjusting the flow rate of the main carrier gas delivered from the carrier gas source 102a. It may also be equipped with a dilution carrier gas source 102b that supplies a carrier gas for dilution (dilution carrier gas) as needed, and a flow rate control valve 103b for adjusting the flow rate of the dilution carrier gas delivered from the dilution carrier gas source 102b.

[0090] The type of carrier gas is not particularly limited and can be selected appropriately depending on the film to be formed. Examples include inert gases such as oxygen, ozone, nitrogen, and argon, and reducing gases such as hydrogen gas and forming gas. The type of carrier gas may be one or more. For example, a dilution gas obtained by diluting the same gas as the first carrier gas with another gas (e.g., diluted 10 times) may be used as the second carrier gas, or air may be used. The number of carrier gas supply points may be one or more.

[0091] (Film forming section) In the film forming unit 140, the mist is heated to cause a thermal reaction, thereby forming a film on the surface of the substrate 110. The film forming unit 140 may be partially or entirely enclosed. For example, as shown in FIG. 1, the film forming unit 140 may include a film forming chamber 107 that houses a substrate mounting unit 112, a nozzle 150, a top plate 153, and sidewalls 155 and completely encloses the film forming unit 140. This configuration reduces impurities in the film to be formed. Furthermore, the film forming chamber 107 is not limited to a completely enclosed shape, and may have gaps that only partially enclose the film forming unit. The film forming unit 140 is equipped with a substrate mounting unit 112 on which a substrate is mounted. The film forming unit 140 may be equipped with a substrate mounting table (susceptor) such as a hot plate 108 for heating the substrate 110. 1, the hot plate 108 may be provided inside the film formation chamber 107, or may be provided outside the film formation chamber 107. It is not necessary to provide a film formation chamber, and in this case, the structure of the film formation apparatus becomes extremely simple.

[0092] 3, the film forming unit 140 is provided with a nozzle 150 above the substrate mounting portion 112 for supplying mist to the substrate 110 in the film forming chamber 107, and a top plate 153 and sidewalls 155 for rectifying the mist supplied from the nozzle 150. That is, the mist supplied from the nozzle 150 onto the substrate 110 passes through the space surrounded by the top plate 153, the sidewalls 155, and the substrate mounting surface 113 of the substrate mounting portion 112, and is rectified to flow toward the outside of the substrate, thereby achieving uniform flow speed and direction of the mist. Note that the outside of the substrate refers to the area excluding the space formed by the substrate surface in the normal direction to the surface.

[0093] (Tabletop) The top plate in the present invention is a member having a surface that intersects with the normal to the substrate mounting surface 113 of the substrate mounting portion 112. As shown in FIG. 3 , the top plate 153 may be installed above the substrate mounting portion 112, and the shape, size, installation position, installation height, installation method, material, and number of top plates are not particularly limited as long as they satisfy the requirements of the present invention. For example, if a film formation chamber 107 is provided, the top plate 153 may be provided between the ceiling of the film formation chamber 107 and the substrate 110 on the substrate mounting portion 112. By providing the top plate 153, the flow of mist is less likely to be disturbed by the flow of ambient gas due to thermal convection during film formation by heat treatment, and the mist supplied from the nozzle 150 is rectified and supplied onto the substrate 110, thereby forming a film with excellent in-plane uniformity in film thickness distribution.

[0094] As mentioned above, the position of the top plate 153 is not particularly limited as long as it is above the substrate mounting portion 112, but for example, as shown in Fig. 3, it can be placed vertically above the upper surface of the hot plate 108 on which the substrate 110 is placed. Such a placement is simple and convenient, and allows a film with sufficiently excellent film thickness uniformity to be formed on the substrate.

[0095] The shape of the top plate can be polygonal, semicircular, circular, or elliptical, but a rectangular shape is preferable because it has good symmetry and ensures stable and good in-plane uniformity of the film thickness distribution of the deposited film.

[0096] The top plate may be in contact with the side of the nozzle, or a gap may be provided. For example, a hole may be formed in the top plate (i.e., doughnut-shaped), and the nozzle may be inserted into this hole. In this case, the distance between the top plate and the side of the nozzle is preferably 2 cm or less, preferably 1 cm or less, and more preferably 0 cm. This is because a film with stable in-plane uniformity of film thickness distribution and good properties can be obtained.

[0097] The distance between the top plate and the nozzle opening surface 152 (see Figures 4-6) is 0 cm when the nozzle and the top plate are integrated, and when they are separate, it is the shortest distance between the top plate and the nozzle opening surface minus the nozzle wall thickness. For example, if the distance between the top plate and the nozzle opening surface is 2.5 cm and the nozzle wall thickness included in the shortest distance is 0.5 cm, the shortest distance between the top plate and the nozzle opening surface is 2.0 cm.

[0098] The top plate may be suspended from the film formation chamber by fixtures 154a or the like, as in the case of top plate 153a of film formation unit 140a shown in Fig. 7, but it is preferable to fix it to the side of the nozzle as shown in Fig. 3. This is because the film to be formed will have stable and good in-plane uniformity in film thickness distribution.

[0099] The top plate may be partially or entirely curved or bent so that the mist can easily flow in a specific direction, as in the case of top plate 153b of film forming unit 140b shown in Fig. 8, or may have a curved surface integrated with the side wall (i.e., a dome shape) as will be described later, but is preferably installed parallel to substrate mounting unit 112 as shown in Fig. 3. More specifically, top plate 153 is preferably installed so that substrate mounting surface 113 of substrate mounting unit 112 and the bottom surface of top plate 153 are parallel. This is because the in-plane uniformity of the film thickness distribution of the film to be formed is stable and good.

[0100] The top plate may be installed in the same plane as the opening surface of the nozzle, or may be closer to the substrate 110 than the opening surface of the nozzle 150, as in the top plate 153c suspended from fixture 154b of film formation unit 140c shown in Fig. 9, or may be farther from the substrate 110 than the opening surface of the nozzle 150, as in the top plate 153d of film formation unit 140d shown in Fig. 10. However, it is more preferable to install the top plate in the same plane as the opening surface of the nozzle 150, as this will result in better in-plane uniformity of the film thickness distribution of the film to be formed.

[0101] The film forming section 140 may be equipped with a position adjustment mechanism (not shown) that can appropriately adjust the difference in height H [cm] between the nozzle opening surface 152 and the substrate 110, and the difference in height I [cm] between the top plate 153 and the substrate mounting surface 113.

[0102] There are no particular restrictions on the thickness of the top plate, but it is preferable that it be 2 mm or more, as this will prevent deformation due to heating during film formation.

[0103] The number of top plates is not particularly limited. As shown in Fig. 3, there may be one top plate for one nozzle, or multiple top plates (here, two top plates 153e, one on the left and one on the right) may be provided for one nozzle as in the film forming unit 140e shown in Fig. 11.

[0104] The material of the top plate is not particularly limited, and possible materials include polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluororesin, metals such as iron, aluminum, stainless steel, and gold, quartz, and glass.

[0105] The height difference I [cm] between the bottom surface of the top plate 153 and the substrate mounting surface 113 of the substrate mounting portion 112 (the shortest height difference) is not particularly limited as long as it is greater than the thickness of the substrate. However, it is preferably 0.15 cm to 6.05 cm (0.15 cm≦I≦6.05 cm), more preferably 0.50 cm to 3.00 cm (0.50 cm≦I≦3.00 cm), and even more preferably 1.00 cm to 2.00 cm (1.00 cm≦I≦2.00 cm). This is because the deposited film will have better in-plane uniformity in film thickness distribution. In the aforementioned spherical structure (dome-shaped) in which the top plate and sidewall are integrated, I is the shortest distance between the substrate mounting area of ​​the substrate mounting surface and the spherical surface in the direction normal to the substrate mounting surface. Furthermore, in the case of a curved top plate as shown in FIG. 8, I is the shortest distance between the bottom surface of the top plate and the substrate mounting surface.

[0106] The area of ​​the bottom of the tabletop (the total area if multiple tabletops are installed) is B [cm 2 ], and the area of ​​the substrate 110 is A [cm 2], it is preferable that B / A≧0.5, and more preferably 1 or more. When B / A≧0.5, a film with better in-plane uniformity of film thickness distribution is obtained. Furthermore, B should be 40 or more (B≧40). Within these numerical ranges, a film with even better in-plane uniformity of film thickness distribution is formed. Furthermore, there are no particular restrictions on the upper limits of B / A or B. If it is greater than the above numerical value, the rectifying effect of the top plate is stably exhibited. However, it is preferable that B / A is 100 or less. This is to prevent the device from becoming larger than necessary. Furthermore, an example of the upper limit of B is 3000 cm 2 This is to prevent the device from becoming larger than necessary.

[0107] (side wall) In the present invention, a sidewall is a member having a surface that intersects with at least one of a plane including the substrate mounting surface 113 of the substrate mounting part 112 and a plane including the bottom surface of the top plate (the surface facing the substrate mounting surface 113). As shown in Fig. 3, the film forming part 140 has sidewalls 155 that face each other across the substrate mounting part 112 to prevent the mist supplied from the nozzle 150 from diffusing laterally without being supplied onto the substrate.

[0108] As shown in FIG. 3 , the sidewalls 155 may be arranged to sandwich the substrate placement portion 112, and their shape, size, installation position, installation height, installation method, material, and number are not particularly limited. For example, if the film formation chamber 107 is provided, the sidewall 155 may be arranged between the side wall of the film formation chamber 107 and the substrate placement portion 112. Alternatively, instead of providing the sidewall 155, the wall of the film formation chamber 107 may function as the sidewall according to the present invention. By providing the sidewall 155 in this manner, it is possible to prevent the mist supplied from the nozzle 150 from mixing with the external gas and diffusing laterally without being supplied onto the substrate. As described above, the synergistic effect of the sidewall 155 and the top plate 153 rectifies the mist supplied from the nozzle 150 and supplies it onto the substrate 110, thereby forming a film with excellent in-plane uniformity in film thickness distribution.

[0109] Here, the shortest distance between the substrate placement area 114 and the sidewall 155 of the substrate placement portion 112 is defined as J [cm]. When the sidewall 155 is in contact with the substrate placement portion 112 as shown in Fig. 3, this shortest distance J [cm] corresponds to the distance between the substrate placement area 114 on the substrate placement surface 113 of the substrate placement portion 112 and the sidewall 155. When the sidewall 155d is not in contact with the substrate placement portion 112 as shown in Fig. 10, this shortest distance J [cm] corresponds to the shortest distance between the substrate placement area 114 and the lower end of the sidewall 155d.

[0110] In the present invention, IJ, which is the product of the difference in height (for example, the shortest difference in height) I [cm] between the bottom surface of the top plate 153 and the substrate mounting surface 113 of the substrate mounting portion 112, satisfies IJ≦15, and although IJ=0 is acceptable, IJ≦12 is preferable, and a range of 1 to 9 (1≦IJ≦9) is more preferable. Furthermore, if IJ>15, the flow of mist will be disturbed by the inflow of ambient gas, diffusion of mist, and thermal convection, resulting in a film with poor in-plane film thickness uniformity.

[0111] Furthermore, the shortest distance J [cm] is not particularly limited as long as IJ≦15, but is preferably 10 cm or less (J≦10), and may be 0 cm (i.e., in contact) as in the side wall 155a of FIG. 7, more preferably 5.0 cm or less, and even more preferably 0.5 cm or more. If J is within this range, the amount of mist supplied to the edge of the substrate 110 is stable and sufficient. When J is small, the effect of a decrease in the amount of mist supplied due to friction between the carrier gas containing mist and the side wall 155 can also be suppressed. For example, J for each of the left and right side walls in FIG. 3 may be different as long as IJ≦15 is satisfied, but it is preferable that they be equal.

[0112] The height of the upper end of the side wall is not particularly limited. It may be installed so that it is lower than the top plate as shown in Figure 3, or it may be installed so that it is higher than the top plate as shown in Figure 8. It may also be installed so that it is at the same height as the top plate as shown in Figure 11.

[0113] The installation form of the side walls is not particularly limited. They may be installed on the hot plate 108 as shown in Fig. 3, or may be fixed to the top plates 153c and 153d as shown in Figs. 9 and 10. When fixed to the top plate, the height of the lower end of the side wall may be lower than the surface of the substrate 110 on the substrate placement part 112 as shown in Fig. 9, or may be higher as shown in Fig. 10. When fixed to the top plate, a member in which the top plate and the side wall are integrated may be used.

[0114] There may be a gap between the side wall and the top plate, as shown in Figures 3, 7, and 8, or there may be no gap, as shown in Figures 9-11. In either case, if IJ≦15, a film with good in-plane uniformity of film thickness distribution can be obtained. The shape of the side wall can be polygonal, semicircular, circular, or elliptical, but a rectangular shape is preferable. This is because it has good symmetry and the film formed will have stable and good in-plane uniformity of film thickness distribution.

[0115] Although the side walls may be partially or entirely curved or bent so as to facilitate the outflow of mist in a specific direction, as in the case of side wall 155f in Fig. 12, it is preferable that the side walls 155 are installed parallel to one another, as in Fig. 3. More specifically, it is preferable that the side walls 155 are installed parallel to one another and symmetrically about the center of the substrate mounting portion 112. This is because the film to be formed will have good in-plane uniformity in the film thickness distribution.

[0116] The thickness of the sidewall is not particularly limited, but a thickness of 2 mm or more is preferable. This is because deformation due to heating during film formation is suppressed. The material of the sidewall is also not particularly limited. Examples include polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluororesin, metals such as iron, aluminum, stainless steel, and gold, quartz, and glass.

[0117] The number of side walls may be any number as long as they are provided facing each other on either side of the substrate placement portion 112, but when two pairs of side walls are provided, it is preferable to provide a gap between the top plate and the side wall as shown in Figures 3, 7, and 8. This is to prevent the supplied gas from remaining and disrupting the flow of mist.

[0118] Alternatively, the film forming section may be provided with a plurality of substrate mounting sections arranged in a row and sandwiched between a pair of side walls, or the film forming section may be provided with a plurality of substrate mounting sections and a plurality of (e.g., three or more) side walls arranged facing each other so as to sandwich the substrate mounting area of ​​each substrate mounting section. In this case, for example, the substrate mounting section may be positioned between each of the three or more side walls. Furthermore, a combination of these configurations may be used, i.e., a plurality of substrate mounting sections may be arranged in multiple rows and three or more side walls may be provided.

[0119] The area of ​​the surface of the side wall on the substrate placement side (if multiple side walls are provided, the total area) is C [cm 2 ], the area of ​​the substrate to be processed is A [cm 2 ], it is preferable that C / A≧0.2, and more preferably 0.5 or more. When C / A≧0.2, a film with good in-plane uniformity of film thickness distribution can be obtained. Furthermore, C should be 20 or more (C≧20). Within these numerical ranges, a film with even better in-plane uniformity of film thickness distribution can be formed. Furthermore, there are no particular restrictions on the upper limits of C / A or C. This is because if it is greater than the above numerical values, the rectification effect due to the side walls will be exerted. However, it is preferable that C / A is 10 or less. This is to prevent the device from becoming larger than necessary. Furthermore, an example of the upper limit of C is 2100 cm 2 This is to prevent the device from becoming larger than necessary.

[0120] The sidewalls and top plate may be equipped with a temperature adjustment mechanism (not shown) capable of adjusting the temperature of the surface facing the substrate placement section 112. If the surface temperature is too high, the evaporation of the mist is accelerated, resulting in an increase in film thickness at positions on the substrate away from the nozzle opening surface. If the temperature is too low, the evaporation of the mist is slowed, resulting in a decrease in film thickness at positions close to the nozzle opening surface. It is preferable to control the temperature at approximately 40 to 120°C. The temperature adjustment mechanism may be one that performs heat exchange using a liquid or gaseous heat medium, one that applies the Peltier effect, or one that uses a ribbon heater or the like. A wide variety of known heat mediums can be used as the heat medium. For example, liquids such as water, glycols, alcohols, and silicone oils, and gaseous heat mediums such as air, nitrogen, helium, and fluorocarbons are preferably used.

[0121] (nozzle) An example of the nozzle 150 is shown in Figure 4. The nozzle 150 includes a connection part 151 that connects the transport part 109 and the nozzle 150, and a nozzle opening surface (also simply referred to as the opening surface) 152 for spraying mist.

[0122] The number of nozzles and the number of openings are not particularly limited as long as they are at least 1. A plurality of nozzles may be provided, as in nozzle 150a in Fig. 5, or a plurality of openings may be provided, as in nozzle 150b in Fig. 6.

[0123] Furthermore, the angle formed between the plane including the nozzle opening surface 152 and the plane including the substrate 110 is not particularly limited. A nozzle may be provided with a nozzle opening surface that is inclined so that the mist flows more easily in a specific direction, but as shown in FIG. 3, it is preferable that the nozzle opening surface is parallel to the substrate mounting surface 113 on which the substrate 110 of the substrate mounting part 112 is mounted. This is because a film with better in-plane uniformity in film thickness distribution can be formed with a simpler structure. Furthermore, it is preferable that the bottom surface of the top plate, the nozzle opening surface, and the substrate mounting surface are all parallel. This is because a film with better in-plane uniformity in film thickness distribution can be formed.

[0124] The film forming unit 140 may be provided with a position adjustment mechanism (not shown) that can appropriately adjust the height difference H [cm] between a point in the nozzle opening surface 152 and the surface of the substrate 110 within a range described below. Furthermore, the nozzle 150 may be configured as an assembly of multiple members, and the area S [cm] of the nozzle opening surface may be adjusted by adjusting the size of the members. 2 ] may be configured to be able to be adjusted appropriately.

[0125] The nozzle 150 may also be equipped with a temperature adjustment mechanism (not shown) capable of adjusting the temperature of the outer surface and the inner surface of the nozzle 150. If the temperatures of the inner and outer surfaces are too high, the evaporation of the mist is accelerated, resulting in an increase in film thickness at positions on the substrate away from the nozzle opening surface. If the temperature is too low, the evaporation of the mist is slowed, resulting in a decrease in film thickness at positions close to the nozzle opening surface. It is preferable to control the temperature at approximately 40 to 120°C. Adjusting the above H changes the distance from the hot plate 108, which in turn changes the temperature of the nozzle 150. For this reason, it is preferable to provide a temperature adjustment mechanism separate from the hot plate 108. The temperature adjustment mechanism may be one that performs heat exchange using a liquid or gaseous heat medium, such as by providing piping around the nozzle 150, or one that utilizes the Peltier effect, or heating using a ribbon heater or the like. A wide variety of known heat mediums can be used as the heat medium. For example, liquids such as water, glycols, alcohols, and silicone oils, and gaseous heat mediums such as air, nitrogen, helium, and fluorocarbons are preferably used.

[0126] In this case, the area S of the nozzle opening surface 152 is preferably 0.1 or more and 400 or less. The difference H in height between the nozzle opening surface 152 and the substrate 110 is preferably 0.1 or more and 6.0 or less, and more preferably 0.2 or more and 3.0 or less. This is because the deposited film will have better in-plane uniformity in film thickness distribution.

[0127] The area of ​​the nozzle opening surface 152 is S [cm 2 ], the area of ​​the substrate is A [cm 2], S / A≦0.3 is preferable, and 0.004≦S / A≦0.15 is more preferable. If S / A≦0.3, a film with better in-plane uniformity of film thickness distribution can be obtained. In addition, in this case, the area A of the substrate is 10 cm 2 It is preferable that it is 50cm or more. 2 The above is more preferable. The larger the area and diameter of the membrane, the larger the area that can be obtained, so there is no particular upper limit. However, an example of the upper limit is an area of ​​750 cm. 2 , or it can be 300 mm in diameter.

[0128] The shape of the nozzle opening surface 152 is not particularly limited. Possible shapes include polygon, circle, and ellipse, but a square shape is preferable, and a rectangle is more preferable. When the shape of the nozzle opening surface 152 is rectangular, L / R≧1 is preferable, where L [cm] is the long axis length of the nozzle opening surface 152 and R [cm] is the maximum length of the substrate in the nozzle long axis direction. This is because L / R≧1 allows a film with good in-plane uniformity in film thickness distribution to be formed on a large-area substrate. There is no particular upper limit to L / R, but since the larger L / R is, the more mist is not supplied to the substrate, it is preferable to set it to 3 or less (L / R≦3).

[0129] (moving mechanism) 1, the film forming section 140 may be provided with a movement mechanism, such as a movement stage 161a, that moves the substrate 110 below the nozzle 150. The direction in which the substrate is moved is not particularly limited.

[0130] 13 and 14 show views of the inside of a film forming unit equipped with a movement mechanism as viewed from above the substrate placement unit. One example is a method in which a movement stage 161a on which the substrate 110 and hot plate 108 are placed is provided, as shown in movement mechanism 160a in FIG. 13, is provided, and the substrate 110 and hot plate 108 move back and forth under the nozzle 150. Another example is a method in which a movement stage 161b on which the substrate 110 and hot plate 108 are placed is used to rotate the substrate 110 and hot plate 108 under the nozzle 150, as shown in movement mechanism 160b in FIG. 14. In this case, a mechanism for rotating the substrate may be provided, and the substrate may be rotated about its own axis.

[0131] 14, a plurality of nozzles 150 may be arranged in the film forming unit 140, and a plurality of substrates 110 may be placed thereon (however, the substrates 110 are not shown because they are blocked by the top plate 153), or a plurality of substrates may be placed in the film forming unit 140 of FIG. 13. Such a structure allows film formation on many substrates at once while maintaining uniformity in the film thickness across the surface, making it even more suitable for mass production.

[0132] Furthermore, when the substrate moving mechanism 160 is provided, the speed and range of substrate movement are not particularly limited, but the number of times a substrate passes under the nozzle is preferably 0.1 times or more per minute, more preferably 0.5 times or more, and even more preferably 1 time or more. By setting the number of times to 0.1 or more, the rising air current caused by localized mist evaporation can be prevented from significantly affecting the supplied gas, reducing the rectifying effect of the top plate, thereby more reliably preventing a decrease in film thickness uniformity. Furthermore, while there is no particular upper limit to the number of times, an increase in the number of times can cause the substrate to become unstable due to inertial forces, so a number of times of 120 times or less is preferable, and 60 times or less is more preferable.

[0133] More specifically, in the case of a moving mechanism such as that shown in FIG. 13, where the width D [mm] of the substrate movement is the substrate movement speed v [mm / min], v / D [ / min] is preferably 0.1 or greater, preferably 0.5 to 120, and more preferably 1 to 60. D is not particularly limited, and is preferably equal to or greater than the diameter [mm] of the substrate (e.g., 100 or greater if the substrate diameter is 4 inches), with no particular upper limit. Increasing D allows for deposition on a large number of substrates per nozzle. However, since the deposition rate per substrate decreases, it is preferable to limit the number of substrates per nozzle to 1,000 mm or less, which is more productive. v is not particularly limited. It is preferably 10 mm / min to 30,000 mm / min, more preferably 30 mm / min to 12,000 mm / min, and more preferably 60 mm / min to 6,000 mm / min. In the case of a rotary type moving mechanism such as that shown in FIG. 14, the rotation speed is preferably 0.1 rpm or more, more preferably 0.5 to 120 rpm, and even more preferably 1 to 60 rpm.

[0134] (Exhaust section) 15, the film forming unit 140 may be provided with an exhaust unit 170 for rectifying the flow of gas (also called "exhaust gas", including mist not used in film formation, gas generated during film formation, carrier gas, etc.) remaining after the mist supplied onto the substrate 110 together with the carrier gas is used in film formation so that it flows outside the substrate 110. The exhaust gas is exhausted from the film forming unit 140 through this exhaust unit 170.

[0135] The straightening effect of the top plate and side walls positioned as described above, and the synergistic effect of the convection generated by the supply of mist from the nozzle 150 and the exhaust of exhaust gas from the exhaust section 170, generate a uniform gas flow above the substrate 110 that is parallel to the surface of the substrate 110, making it possible to produce a more uniform film on the substrate 110.

[0136] The shape and configuration of the exhaust unit 170 are not particularly limited as long as it is configured to exhaust the exhaust gas from the film forming unit 140. For example, as shown in Fig. 15, an exhaust port 111 may be provided on the side of the substrate 110 to perform forced exhaust. A configuration in which a carrier gas or the like supplied from the nozzle 150 between the top plate 153 and the substrate 110 flows to the outside of the substrate 110 is particularly preferable.

[0137] The exhaust unit 170 may be the exhaust port 111 itself provided in the film formation unit 140 as described above, or may be the exhaust port 111 plus a means for forced exhaust. An example of such an exhaust unit 170 is shown in FIG. 16. For example, an exhaust unit 172 provided outside the film formation chamber 107 forcibly exhausts the gas inside the film formation chamber 107 from the exhaust port 111 provided on the side of the film formation chamber 107 through an exhaust duct 171. The exhaust unit 172 is provided with an exhaust flow rate control valve 173 for adjusting the exhaust flow rate, so that the exhaust flow rate can be adjusted.

[0138] The shape of the exhaust port 111 is not particularly limited and may be circular, rectangular, or the like. The exhaust section 170 may be provided in one location, or in two or more locations as shown in Fig. 15. When providing two or more locations, it is preferable to provide them symmetrically with respect to the center of the nozzle opening surface. This is because a film with better in-plane uniformity in film thickness distribution can be stably formed.

[0139] The exhaust unit 170 may also be provided with a temperature control mechanism (not shown) that controls the temperature of part or the entire unit in order to suppress the precipitation of solids within the exhaust unit. Such a temperature control mechanism suppresses the precipitation of solids within the exhaust unit 170, making it easier to control the exhaust flow rate. The temperature adjustment mechanism may perform heat exchange using a liquid or gaseous heat medium by providing piping around the exhaust duct 171, or may utilize the Peltier effect, or may use heating such as a ribbon heater. 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, nitrogen, helium, and fluorocarbons.

[0140] Furthermore, the material of the components constituting the exhaust section 170 is not particularly limited, and examples thereof include polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluororesin, metals such as iron, aluminum, stainless steel, and gold, quartz, and boron nitride. Boron nitride is preferable because it can prevent the flow of exhaust gas from becoming uneven due to rust or solid precipitation caused by unintended reactions with unreacted raw materials.

[0141] Furthermore, as described above, when the film formation chamber 107 includes the moving mechanism 160, the exhaust port 111 may be provided on the moving mechanism 160, so that the exhaust port 111 (exhaust unit 170) can be moved.

[0142] (Transportation section) The transfer unit 109 connects the mist generation unit 120 and the film formation unit 140. Mist is transferred by a carrier gas from the mist generation source 104 of the mist generation unit 120 to the nozzle 150 of the film formation unit 140 via the transfer unit 109. The transfer unit 109 can be, for example, a supply pipe 109a. The supply pipe 109a can be, for example, a quartz pipe or a resin tube.

[0143] (Raw material solution) The raw material solution 104a is not particularly limited as long as it contains a material that can be turned into mist, and may be an inorganic or organic material. A solution (such as an aqueous solution) of a metal or metal compound is preferably used as the raw material solution, and one or more metals selected from gallium, iron, indium, aluminum, vanadium, titanium, chromium, rhodium, nickel, and cobalt can be used. In particular, if the raw material solution contains gallium, a gallium oxide film with good in-plane uniformity in film thickness distribution can be formed.

[0144] The raw material solution is not particularly limited as long as it can turn the metal solution into a mist. A suitable raw material solution is one in which the metal is dissolved or dispersed in an organic solvent or water in the form of a complex or salt. Examples of complexes include acetylacetonate complexes, carbonyl complexes, ammine complexes, and hydride complexes. Examples of salts include metal chlorides, metal bromides, and metal iodides. Furthermore, solutions in which the metals are dissolved in hydrobromic acid, hydrochloric acid, hydroiodic acid, or the like can also be used as aqueous salt solutions. The solute concentration is preferably 0.01 to 1 mol / L.

[0145] The source solution may also contain additives such as halogen-containing compounds (e.g., hydrohalic acid) or oxidizers. This allows for the deposition of crystalline oxide films with excellent in-plane uniformity in film thickness distribution. Examples of hydrohalic acids include hydrobromic acid, hydrochloric acid, and hydroiodic acid, with hydrobromic acid and hydroiodic acid being preferred. Examples of oxidizers include peroxides such as hydrogen peroxide (H2O2), sodium peroxide (Na2O2), barium peroxide (BaO2), and benzoyl peroxide (C6H5CO)2O2, as well as hypochlorous acid (HClO), perchloric acid, nitric acid, ozone water, and organic peroxides such as peracetic acid and nitrobenzene.

[0146] Furthermore, the raw material solution may contain a dopant. The dopant is not particularly limited. Examples of the dopant include n-type dopants such as tin, germanium, silicon, titanium, zirconium, vanadium, and niobium, and p-type dopants such as copper, silver, tin, iridium, and rhodium. The dopant concentration is, for example, about 1.0×10 -9 It may be up to 1.0 mol / L, and may be about 1.0 × 10 -7 The concentration may be as low as 0.01 mol / L or less, or as high as about 0.01 mol / L or more.

[0147] (substrate) The substrate 110 is not particularly limited as long as it can support a film and can be used for film formation. The material of the substrate 110 is also not particularly limited, and known substrates can be used, including organic and inorganic compounds. Examples include polysulfone, polyethersulfone, polyphenylene sulfide, polyetheretherketone, polyimide, polyetherimide, fluororesin, metals such as iron, aluminum, stainless steel, and gold, quartz, glass, calcium carbonate, gallium oxide, and zinc oxide. In addition, single-crystal substrates such as silicon, sapphire, lithium niobate, lithium tantalate, SiC, GaN, iron oxide, and chromium oxide are also suitable. In the present invention, the above single-crystal substrates are preferred. These substrates enable the production of higher-quality crystalline oxide films. Sapphire substrates, lithium tantalate substrates, and lithium niobate substrates are particularly inexpensive and industrially advantageous. The thickness of the substrate is not particularly limited, but is preferably 10 to 2000 μm, more preferably 50 to 800 μm.

[0148] In addition, as a substrate, for example, the area of ​​the surface on which the film is formed (the surface to be processed) is 50 cm 2 A substrate having a diameter of 4 inches (100 mm) or more can be used, which is preferable because it allows deposition of a film with good in-plane uniformity of film thickness distribution over a large area. There are no particular limitations on the upper limit of the area or diameter of the substrate, but for example, an area of ​​750 cm 2 , or it can be 300 mm in diameter.

[0149] [Film forming method] Referring again to FIG. 1 , an example of a film formation method according to the present invention will be described below. The film formation method according to the present invention includes a mist generation process for misting a raw material solution to generate the mist, a mist transport process for transporting the mist to a film formation unit, and a film formation process for supplying the mist from a nozzle above the substrate mounting unit onto a substrate mounted on the substrate mounting unit in the film formation unit and performing heat treatment to form a film. The film formation method according to the present invention is characterized in that, by performing film formation using a film formation apparatus configured as described above for the film formation apparatus, it is possible to form a film with better in-plane film thickness uniformity than conventional methods. Specifically, the film formation process is characterized in that the mist is supplied from a nozzle into a space surrounded by a top plate having a height difference of I [cm] between the substrate mounting surface of the substrate mounting unit and its bottom surface, and sidewalls arranged opposite to each other across the substrate mounting unit, the shortest distance from the substrate mounting area of ​​the substrate mounting unit being J [cm], and the top plate and sidewalls are arranged so that IJ≦15.

[0150] A more detailed description will be given below. First, the raw material solution 104a is placed in the mist generating source 104 of the mist generating unit 120, and the substrate 110 such as a crystalline substrate is placed on the hot plate 108, which is then operated.

[0151] Next, the flow rate control valves 103a and 103b are opened to supply the main carrier gas from the carrier gas source 102a and the dilution carrier gas from the dilution carrier gas source 102b into the film formation chamber 107, thereby sufficiently replacing the atmosphere in the film formation chamber 107 with the carrier gas, and adjusting and controlling the flow rates of the main carrier gas and the dilution carrier gas, respectively.

[0152] In the mist generating step, the ultrasonic vibrator 106 is vibrated, and the vibration is propagated to the raw material solution 104a through the water 105a, thereby turning the raw material solution 104a into mist and generating the mist.

[0153] Next, in the mist transport step of transporting the mist by a carrier gas, the mist is transported by the carrier gas from the mist-forming unit 120 to the film-forming unit 140 via the transport unit 109 and introduced into the film-forming chamber 107 .

[0154] In the film formation process, mist is supplied from a nozzle 150 provided above the substrate placement section 112 (hot plate 108 on which substrate 110 is placed) into a space surrounded by a top plate 153, side walls 155, and substrate 110 of the film formation section. The supplied mist is rectified by the top plate and side walls provided at specified positions and supplied onto the substrate 110, where it is thermally treated by the heat of the hot plate 108 in the film formation chamber 107, causing a thermal reaction and forming a film on the substrate 110. This film formation method makes it possible to form a film with better film thickness uniformity within the substrate surface than conventional methods.

[0155] 24 and 25, the flow of mist in the film forming unit 140 will be described in more detail. FIG. 25 shows the inside of the side wall of FIG. 24 (with the side wall removed). As shown in FIG. 25, mist is supplied from a nozzle 150 from above the surface of a substrate 110 on a mounting unit 112. Thereafter, the mist flows in the direction 180 while the top plate 153 and the side wall 155 suppress disturbances to the mist flow due to thermal convection caused by the hot plate 108 and the inflow of outside air, and is naturally exhausted from above the substrate 110. When forced exhaust is provided as in FIG. 17, the mist flows in the direction 180 while the exhaust flow is controlled by the exhaust unit 170, and the mist is forcibly exhausted from above the substrate 110.

[0156] In addition, depositing a film while moving the substrate 110 below the nozzle 150 using a moving mechanism is effective when forming a film over a large area, and is also effective for depositing a superior film with a more uniform in-plane thickness.

[0157] The flow rate of the carrier gas is not particularly limited. For example, when forming a film on a substrate with a diameter of 4 inches (100 mm), the flow rate is preferably 1 to 80 L / min, and more preferably 4 to 40 L / min. The flow rate Q of the carrier gas in the present invention is a value measured at 20°C and atmospheric pressure. When measured at other temperatures and pressures or when a different type of flow rate (mass flow rate, etc.) is measured, it can be converted to a volumetric flow rate at 20°C and atmospheric pressure using the gas state equation.

[0158] The thermal reaction of the mist in the film forming section 140 is not particularly limited as long as the mist reacts due to heating. The reaction conditions can be set appropriately depending on the raw material and the film to be formed. For example, the heating temperature can be set in the range of 120 to 600°C, preferably in the range of 200 to 600°C, and more preferably in the range of 300 to 550°C. The heating temperature is T [°C], and the area of ​​the nozzle opening surface 152 is S [cm 2 ] and the flow rate of the carrier gas is Q [L / min], ST / Q is preferably 40 or more (ST / Q≧40), and more preferably 100 or more and 2000 or less (100≦ST / Q≦2000). When ST / Q≧40, the film has better in-plane uniformity of the film thickness distribution.

[0159] The area of ​​the nozzle opening surface 152 is S [cm 2 ], the flow rate of the carrier gas is Q [L / min], and the difference in height between the nozzle opening surface 152 and the substrate 110 (for example, the longest distance between a point in the nozzle opening surface 152 and the surface of the substrate 110) is H [cm], then SH / Q should be 0.015 or more, and preferably 0.1 to 20. When SH / Q≧0.015, the film has better in-plane uniformity in the film thickness distribution.

[0160] At this time, the velocity of the gas in the direction perpendicular to the substrate at the nozzle opening surface 152 is preferably 0.01 to 8.0 m / s, more preferably 0.1 to 2.0 m / s. The velocity of the gas in the direction perpendicular to the substrate at the nozzle opening surface 152 is calculated by assuming that the flow rate of the carrier gas at 20°C and normal pressure is Q [L / min] and the area of ​​the nozzle opening surface 152 is S [cm 2] and convert to units.

[0161] The thermal reaction may be carried out under any of the following atmospheres: vacuum, non-oxygen atmosphere, reducing gas atmosphere, air atmosphere, and oxygen atmosphere, and may be appropriately set depending on the film to be formed. The reaction pressure may be atmospheric pressure, elevated pressure, or reduced pressure, but film formation under atmospheric pressure is preferred because it simplifies the device configuration.

[0162] When exhaust is performed during the film formation process (exhaust process), the exhaust flow rate is not particularly limited. However, when the flow rate of the carrier gas supplied from the nozzle 150 is Q [L / min] and the flow rate of the exhaust gas exhausted from the exhaust unit 170 is E [L / min], E / Q is preferably 5.0 or less, and more preferably 0.5 to 3.0. This is because a film with better in-plane uniformity of film thickness distribution is obtained. In addition, E exhausted from the exhaust unit 170 at this time can be measured using a flow meter at the exhaust port 111 at 20°C and atmospheric pressure, or can be calculated by multiplying the linear velocity measured using an anemometer by the area of ​​the opening surface of the exhaust port 111. When the flow rate is measured using other methods, temperatures, and pressures, it can be converted to a volumetric flow rate at 20°C and atmospheric pressure using the gas state equation.

[0163] In the present invention, after the film is formed, an annealing treatment may be performed. The temperature of the annealing treatment is not particularly limited, but is preferably 600°C or less, more preferably 550°C or less, so as not to impair the crystallinity of the film. The treatment time of the annealing treatment is not particularly limited, but is preferably 10 seconds to 10 hours, more preferably 10 seconds to 1 hour.

[0164] The film formation may be directly performed on the substrate, or may be laminated on an intermediate layer formed on the substrate. The intermediate layer is not particularly limited, and for example, it can be mainly composed of an oxide containing any one of aluminum, titanium, vanadium, chromium, iron, gallium, rhodium, indium, and iridium. More specifically, they are Al2O3, Ti2O3, V2O3, Cr2O3, Fe2O3, Ga2O3, Rh2O3, In2O3, Ir2O3. Also, when two elements selected from the above metal elements are defined as A and B, a binary metal oxide represented by (A x B 1-x )2O3 (0 < x < 1), or when three elements selected from the above metal elements are defined as A, B, and C, a ternary metal oxide represented by (Al x B y C 1-x-y )2O3 (0 < x < 1, 0 < y < 1) can be used.

[0165] (Peeling) The substrate 110 may be peeled from the oxide semiconductor film. The peeling means is not particularly limited and may be a known means. For example, means for peeling by applying mechanical impact, means for peeling by applying heat and using thermal stress, means for peeling by applying vibration such as ultrasonic waves, means for peeling by etching, laser lift-off, etc. can be mentioned. By the above peeling, the oxide semiconductor film can be obtained as a self-supporting film.

[0166] (Electrode) When the oxide semiconductor film or laminate according to the present invention is applied to a semiconductor device, electrodes required for constructing the semiconductor device can be formed using a conventional method. This includes vapor deposition, sputtering, CVD, plating, and printing methods, such as bonding with a resin. Materials for the electrodes include metals such as Al, Ag, Ti, Pd, Au, Cu, Cr, Fe, W, Ta, Nb, Mn, Mo, Hf, Co, Zr, Sn, Pt, V, Ni, Ir, Zn, In, and Nd; conductive metal oxide films such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); and organic conductive compounds such as polyaniline, polythiophene, and polypyrrole. The thickness of the electrodes is preferably 1 to 1,000 nm, more preferably 10 to 500 nm. [Example]

[0167] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0168] Example 1 In this example, a film forming apparatus as shown in Figures 17 and 18 was used. In the film forming section 140e, two top plates 153e were fixed so as to be in the same plane as the nozzle opening surface. The area of ​​the top plates was defined as B [cm 2 ], B=600, and the difference in height between the substrate mounting surface of the substrate mounting portion 112 (the upper surface of the hot plate 108) and the top plate was set to I=2.05 cm.

[0169] 18 is a view of the film formation chamber shown in FIG. 17 as seen from the side of FIG. 17. As shown in FIG. 18, a pair of side walls 155e was installed on the substrate placement part 112 so as to be in contact with the top plate 153e. At this time, the shortest distance J between the substrate placement area of ​​the substrate placement part and the side walls was J=2.50 cm, and IJ=5.1. The side walls had a thickness of 3 mm, and the area of ​​the opposing surfaces of the side walls was C [cm 2 ], C=120.

[0170] Gallium iodide was added to water and dissolved by stirring at 60°C for 60 minutes to prepare a 0.1 mol / L aqueous solution, which was designated as raw material solution 104a. The raw material solution 104a obtained as described above was placed in mist generating source 104. The temperature of the solution at this time was 25°C.

[0171] Next, a c-plane sapphire substrate having a diameter of 4 inches (100 mm) was placed on the hot plate 108 in the film formation chamber 107 as the substrate 110, and the hot plate 108 was operated to raise the temperature to 500°C.

[0172] Next, the flow control valves 103a and 103b were opened to supply nitrogen gas as a carrier gas from the carrier gas source 102a (main carrier gas) and the dilution carrier gas supply source 102b (dilution carrier gas) into the film formation chamber 107, and the atmosphere in the film formation chamber 107 was thoroughly replaced with these carrier gases, while the flow rate of the main carrier gas was adjusted to 12 L / min and the flow rate of the dilution carrier gas was adjusted to 12 L / min, respectively.

[0173] 16, the exhaust flow rate adjustment valve 173 was adjusted so that the exhaust amount E [L / min] at the exhaust port 111 was 72. At this time, E / Q=3.0.

[0174] Next, the ultrasonic vibrator 106 was vibrated at 2.4 MHz, and the vibration was propagated to the raw material solution 104a through the water 105a, thereby turning the raw material solution 104a into mist and generating mist.

[0175] This mist was supplied to the substrate 110 by a carrier gas through the supply pipe 109a and the nozzle 150. The nozzle 150 used had a nozzle opening surface 152 with a rectangular shape, and the area of ​​the nozzle opening surface 152 was S [cm 2 ], the flow rate of the carrier gas is Q [L / min], and the difference in height between the nozzle opening surface 152 and the substrate 110 (the longest distance between a point in the nozzle opening surface 152 and the surface of the substrate 110) is H [cm]. The adjustment was made so that SH / Q = 0.5. In this case, S = 6.0 [cm 2], H=2.0[cm], Q=24[L / min].

[0176] Then, under atmospheric pressure and at 500°C, the mist was thermally reacted in the film formation chamber 107 while gas was being exhausted from the exhaust port 111, to form a thin film of gallium oxide (α-Ga2O3) having a corundum structure on the substrate 110. The film formation time was 360 minutes.

[0177] When the heat treatment temperature is T [℃], ST / Q = 125, and the area of ​​the substrate is A [cm 2 ], S / A=0.076, the long axis length of the nozzle opening surface 152 is L [cm], and the maximum length of the substrate in the nozzle long axis direction is R [cm], L / R=1.2. At this time, T=500 [°C], A=78.5 [cm 2 ], L=12[cm], R=10[cm]. Also, B / A=7.6, C / A=1.5.

[0178] The substrate and hot plate were reciprocated by a moving mechanism 160a as shown in FIG. 13 at a speed of 15 cm / min so as to pass under the nozzle once per minute.

[0179] Example 2 Film formation was performed in the same manner as in Example 1, with J=5.00 cm and IJ=10.3, with a gap of 2.5 cm provided between the top plate 153e and the side wall 155 as shown in Figure 19, no exhaust port 111 provided, and the film formation time set to 120 minutes.

[0180] (Comparative Example 1) The same procedures as in Example 1 were carried out except that a film formation apparatus was used that did not have a top plate or side walls as shown in Figure 20 and did not satisfy IJ≦15, the film formation time was 120 minutes, the carrier gas flow rate Q was 12 L / min, and the exhaust flow rate E was 36 L / min. At this time, SH / Q = 1 and ST / Q = 250. The shortest distance between the substrate mounting area and the wall (side wall) of the film formation chamber was 12 cm, and the difference (distance) in height between the substrate mounting surface and the underside of the ceiling wall of the film formation chamber was 50 cm.

[0181] (Comparative Example 2) 21 was not provided with the side wall 155, and a film formation apparatus that did not satisfy IJ≦15 was used, and the film formation time was set to 20 minutes, but the same procedures were carried out as in Example 2. The shortest distance between the substrate mounting area and the wall (side wall) of the film formation chamber was 12 cm, and the difference (distance) in height between the substrate mounting surface and the bottom surface of the top plate was 2.05 cm.

[0182] (Comparative Example 3) Film formation was carried out in the same manner as in Example 2, except that I=3.05 cm, H=3.00 cm, and the film formation time was 20 minutes. At this time, IJ=15.3, and SH / Q=0.75.

[0183] Comparative Example 4 I = 6.05 cm, H = 6.00 cm, Q = 48 L / min, C = 360 cm 2 The film was formed in the same manner as in Example 2, except that the film formation time was 40 minutes. At this time, C / A=4.6, IJ=30.3, SH / Q=0.75, and ST / Q=62.5.

[0184] Example 3 B=420cm 2 , C=360cm 2 , S=2.4cm 2 Film formation was performed in the same manner as in Example 1, except that H = 6.00 cm, I = 6.05 cm, J = 2.00 cm, Q = 48 L / min, E = 24 L / min, and the film formation time was 60 minutes. At this time, B / A = 5.3, C / A = 4.6, E / Q = 0.5, IJ = 12.1, S / A = 0.030, SH / Q = 0.3, and ST / Q = 25.

[0185] Example 4 B=750cm 2 , C=6cm 2 , S=12cm 2Film formation was performed in the same manner as in Example 1, except that H = 0.10 cm, I = 0.15 cm, J = 7.50 cm, Q = 12 L / min, E = 12 L / min, and the film formation time was 60 minutes. At this time, B / A = 9.5, C / A = 0.1, E / Q = 1.0, IJ = 1.1, S / A = 0.15, SH / Q = 0.1, and ST / Q = 500.

[0186] Example 5 In the film forming apparatus of FIG. 17, the nozzle was installed so that the nozzle opening surface 152 was located directly above the edge of the substrate 110, and the substrate was not moved. B=300 cm 2 Except for changing the film formation time to 300 minutes, film formation was carried out in the same manner as in Example 1. At this time, B / A=3.8.

[0187] Example 6 Film formation was performed in the same manner as in Example 1, except that an inclined top plate as shown in Figure 22 was used, J = 5.00 cm, and the film formation time was 60 minutes. At this time, IJ = 10.3. In addition, the top plate 153h was inclined so that the side of the bottom surface not in contact with the nozzle 150 was 4 mm higher than the part in contact.

[0188] Example 7 Film formation was carried out in the same manner as in Example 1, except that E was 120 L / min and the film formation time was 60 minutes. At this time, E / Q was 5.0.

[0189] Example 8 Except for changing E to 360 L / min and the film formation time to 60 minutes, film formation was carried out in the same manner as in Example 1. At this time, E / Q was 15.0.

[0190] Example 9 The substrate was a 6-inch (150 mm diameter) c-plane sapphire substrate, and B = 1000 cm 2 , S=9cm 2 The film was formed in the same manner as in Example 1, except that Q = 36 L / min, E = 36 L / min, and the film formation time was 60 minutes. 2, B / A=5.7, C / A=0.7, E / Q=1.0, S / A=0.05, R=15cm, L=18cm.

[0191] Example 10 In the film forming apparatus of FIG. 17, the nozzle was installed so that the opening surface 152 of the nozzle was located directly above the edge of the substrate 110, the substrate was not moved, the substrate was a 6-inch (150 mm diameter) c-plane sapphire substrate, and B=500 cm 2 , C=30cm 2 , S=9cm 2 The film formation was carried out in the same manner as in Example 1, except that Q = 36 L / min, E = 36 L / min, and the film formation time was 60 minutes. 2 , B / A=2.8, C / A=0.2, E / Q=1.0, S / A=0.05, R=15cm, L=18cm.

[0192] Example 11 The same procedure as in Example 1 was repeated, except that an aluminum acetylacetonate complex was dissolved in a hydrochloric acid solution to prepare a 0.1 mol / L solution, which was used as the raw material solution, H = 3.00 cm, I = 3.05 cm, J = 3.00 cm, T = 550°C, and the deposition time was 45 minutes. At this time, IJ = 9.2, SH / Q = 0.75, and ST / Q = 137.5.

[0193] Example 12 Gallium nitrate was dissolved in water to prepare a 0.1 mol / L solution, which was used as the raw material solution. B = 40 cm 2 The film was formed in the same manner as in Example 5, except that E was 24 L / min and the film formation time was 45 minutes. At this time, E / Q was 1.0 and B / A was 0.5.

[0194] (film thickness distribution measurement) The film thickness of the thin film formed on the substrate 110 was measured at 25 points on the surface of the substrate 110 using an optical interference film thickness meter F50. The average film thickness was calculated from each value and shown in Table 1. Film thickness distribution [±%] = (maximum film thickness - minimum film thickness) / ((average film thickness) × 2) × 100 The film thickness distribution calculated as above is shown in Table 1. The film formation rate is calculated by dividing the average film thickness by the film formation time, and is shown in Table 1. Figure 23 shows a plot of the in-plane film thickness distribution against the IJ.

[0195] [Table 1]

[0196] 23, comparing Examples 1 to 12 with Comparative Examples 1 to 4, it was found that by performing film formation using the film formation apparatus according to the present invention, it is possible to obtain a gallium oxide (α-Ga2O3) film with excellent in-plane uniformity in film thickness distribution. Furthermore, it is presumed that the invention described in the above-mentioned Patent Document 5, which differs from the present invention in the presence or absence of a mechanism for rectifying the mist, did not result in a film with good in-plane uniformity in film thickness distribution on substrates with a diameter of 4 inches (100 mm) or more.

[0197] 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. a mist generating unit that generates mist by misting the raw material solution; a carrier gas supply unit that supplies a carrier gas that carries the mist generated in the mist generating unit; a film forming unit that forms a film by heat-treating the mist carried by the carrier gas, The film forming unit a substrate placement section on which the substrate is placed; a nozzle located above the substrate placement part and supplying the mist onto the substrate; a top plate located above the substrate placement unit and rectifying the mist supplied from the nozzle; side walls provided opposite to each other so as to sandwich the substrate placement section, a film forming apparatus characterized in that, when a difference in height between the substrate mounting surface of the substrate mounting portion and the bottom surface of the top plate is I [cm] and a shortest distance between the substrate mounting area of ​​the substrate mounting portion and the side wall is J [cm], IJ≦15.

2. 2. The film forming apparatus according to claim 1, wherein the bottom surface of the top plate, the opening surface of the nozzle, and the substrate mounting surface are all parallel to one another.

3. 2. The film forming apparatus according to claim 1, wherein the I [cm] is 0.15 cm or more and 6.05 cm or less.

4. 2. The film forming apparatus according to claim 1, wherein the J [cm] is 5.0 cm or less.

5. The area of ​​the bottom surface of the top plate is B [cm ２ 2. The film forming apparatus according to claim 1, wherein B≧40 when

6. The area of ​​the substrate to be processed is defined as A [cm ２ ], the area of ​​the bottom surface of the top plate is B [cm ２ 2. The film forming apparatus according to claim 1, wherein B / A≧0.5 when the ratio of B / A is 0.

5.

7. The area of ​​the surface of the side wall on the substrate placement portion side is defined as C [cm ２ 2. The film forming apparatus according to claim 1, wherein C≧20 when

8. The area of ​​the substrate to be processed is defined as A [cm ２ ], the area of ​​the opposing surfaces of the side walls is C [cm ２ 2. The film forming apparatus according to claim 1, wherein C / A≧0.2 when

9. 2. The film forming apparatus according to claim 1, further comprising an exhaust section for exhausting exhaust gas from the film forming section.

10. 2. The film forming apparatus according to claim 1, further comprising a moving mechanism for moving the substrate below the nozzle.

11. 10. The film forming apparatus according to claim 1, wherein the film forming unit includes a film forming chamber, and the side wall is a wall of the film forming chamber.

12. 11. The film forming apparatus according to claim 1, wherein the film forming section further comprises a film forming chamber that accommodates the substrate placement section, the nozzle, the top plate, and the side wall therein.

13. A film formation method for forming a film on a substrate by heat-treating a mist of a raw material solution, comprising: a mist generating step of misting the raw material solution to generate mist; a mist transport step of transporting the mist to a film forming unit by a carrier gas; a film-forming step of supplying the mist onto the substrate placed on a substrate-placing part in the film-forming part from a nozzle provided above the substrate-placing part to perform heat treatment and form a film; Including, In the film forming step, a top plate provided above the substrate mounting portion, the top plate having a height difference of I [cm] between the substrate mounting surface of the substrate mounting portion and the bottom surface of the top plate, and side walls provided opposite to each other across the substrate mounting portion, the side walls having a shortest distance of J [cm] from the substrate mounting area of ​​the substrate mounting portion, the space being surrounded by the top plate and the side walls such that IJ≦15.

14. 14. The film forming method according to claim 13, wherein the top plate and the side wall are provided so that the bottom surface of the top plate, the opening surface of the nozzle, and the substrate mounting surface are all parallel to each other.

15. The film forming method according to claim 13, wherein the top plate is provided so that a difference I [cm] in height between the substrate placement surface of the substrate placement portion and the bottom surface of the top plate is 0.15 cm or more and 6.05 cm or less.

16. 14. The film forming method according to claim 13, wherein the sidewall is provided so that the J [cm] is 5.0 cm or less.

17. The area of ​​the bottom surface of the top plate is B [cm ２ 14. The film forming method according to claim 13, wherein the top plate is provided so that B≧40 when the temperature is 1000° C. or higher.

18. The area of ​​the substrate to be processed is defined as A [cm ２ ], the area of ​​the bottom surface of the top plate is B [cm ２ 14. The film forming method according to claim 13, wherein the top plate is provided so that B / A≧0.5 when the ratio of B / A is 0.5 or more.

19. The area of ​​the surface of the side wall on the substrate placement portion side is defined as C [cm ２ 14. The film forming method according to claim 13, wherein the side walls are provided so that C≧20 when the ratio of the thickness of the film to the thickness of the substrate is 1 / 2.

20. The area of ​​the substrate to be processed is defined as A [cm ２ ], the area of ​​the opposing surfaces of the side walls is C [cm ２ 14. The film forming method according to claim 13, wherein the side walls are provided so that C / A≧0.2 when the ratio of the thickness of the side walls to the thickness of the film is 1 / 2.

21. The film forming method according to claim 13, further comprising an exhaust step of exhausting exhaust gas from the film forming section.

22. 22. The film forming method according to claim 21, wherein when the flow rate of the carrier gas supplied from the nozzle is Q [L / min] and the flow rate of the exhaust gas is E [L / min], E / Q is 5.0 or less.

23. 14. The film forming method according to claim 13, wherein the substrate is moved below the nozzle.

24. 14. The film forming method according to claim 13, wherein the raw material solution contains gallium.

25. 14. The film forming method according to claim 13, wherein the raw material solution contains a halogen.

26. The substrate has a surface area of ​​50 cm ２ 26. The film forming method according to claim 13, wherein a film forming apparatus having a diameter of 4 inches (100 mm) or more is used.

27. A stack of an oxide semiconductor film containing gallium as a main component and a substrate, The oxide semiconductor film of the stack has an area of ​​70 cm ２ or larger, or the surface size is 4 inches (100 mm) or larger in diameter, the in-plane distribution of the film thickness of the oxide semiconductor film is less than ±5%; The laminate, wherein the substrate is a c-plane sapphire substrate.

28. 28. The laminate according to claim 27, wherein the oxide semiconductor film has a corundum structure.

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