Sputtering apparatus and film formation method

Abstract

Provided is a sputtering apparatus comprising: a placement table on which a target material that is manufactured in a treatment container and that is made of a low melting point metal or a low melting point alloy is to be placed; a holding part that opposes the placement table and that holds a substrate; a first gas supply part that has a first gas hole and that supplies a first gas into the treatment container through the first gas hole; a second gas supply part that has a second gas hole at a location closer to the target material than the first gas hole and that supplies a second gas into the treatment container through the second gas hole; a power supply that applies a voltage between the placement table and the holding part; and a control unit. The control unit controls the first gas supply part and the second gas supply part, supplies the first gas and the second gas such that nitrogen is contained more in a gas around the substrate than in a gas around the target material, performs sputtering on the target material by using the voltage applied from the power supply, and forms, on the substrate, a nitride film made of the low melting point metal or the low melting point alloy.

Description

[Technical Field]

[0001] The present disclosure relates to a sputtering apparatus and a film formation method. [Background technology]

[0002] For example, Patent Documents 1 and 2 disclose methods for manufacturing target materials. In Patent Document 1, gallium (Ga) or a Ga alloy is poured into a backing plate in a liquid state. The backing plate holding the liquid Ga is then heat-treated in a reduced pressure state or a hydrogen gas atmosphere at a temperature equal to or higher than the melting point of the Ga or Ga alloy, and the Ga or Ga alloy is then cooled until it becomes solid, thereby manufacturing the target material.

[0003] For example, in Patent Document 2, a target material is placed in a supply vessel of a raw material chamber, and the raw material chamber is evacuated to form a vacuum atmosphere. After that, the supply vessel is heated to connect the target material, a supply pressure adjusting gas is introduced into the raw material chamber, a sputtering gas is introduced into a deposition vessel by the pressure difference, and a sputtering voltage is applied to the deposition vessel to sputter the liquid target material.

[0004] For example, Patent Document 3 proposes a method for forming a nitride semiconductor film, which includes a step of intermittently sputtering a gallium nitride target material in a vacuum chamber containing nitrogen and argon, and a step of depositing sputtered gallium nitride particles scattered from the target material in the vacuum chamber onto an object at a temperature of 560°C or higher and 650°C or lower. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-260974 [Patent Document 2] Japanese Patent Publication No. 2020-186463 [Patent Document 3] International Publication No. 2020 / 075599 Summary of the Invention [Problem to be solved by the invention]

[0006] The present disclosure provides a technique that can form a nitride film of a low-melting-point metal or low-melting-point alloy while preventing nitridation of the target material. [Means for solving the problem]

[0007] According to one aspect of the present disclosure, there is provided a processing vessel, a processing vessel provided in the processing vessel, and a processing vessel manufactured in the processing vessel. Gallium, indium, or alloys of gallium and indium a mounting table on which the target material is placed, a holder facing the mounting table and configured to hold a substrate, a first gas supply unit having a first gas hole and configured to supply a first gas through the first gas hole into the processing vessel, a second gas supply unit having a second gas hole located closer to the target material than the first gas hole and configured to supply a second gas through the second gas hole into the processing vessel, a power source configured to apply a voltage between the mounting table and the holder, and a control unit, At least a portion of the second gas holes is provided in the mounting table, The control unit controls the first gas supply unit and the second gas supply unit to supply the first gas and the second gas so that the gas around the substrate contains more nitrogen than the gas around the target material, and controls the power source to sputter the target material by the applied voltage, thereby sputtering the target material onto the substrate. Gallium, indium, or alloys of gallium and indium A sputtering apparatus for forming the nitride film is provided. [Effects of the Invention]

[0008] According to one aspect, a nitride film of a low-melting point metal or a low-melting point alloy can be formed while preventing nitridation of the target material. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a sputtering apparatus according to an embodiment. [Figure 2] 2 is a flowchart illustrating a film forming method according to an embodiment. [Figure 3]FIG. 10 is a diagram showing another example of the gas supply unit of the sputtering apparatus according to the embodiment. [Figure 4] FIG. 10 is a diagram showing another example of the gas supply unit of the sputtering apparatus according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0011] [Nitride semiconductor film] Gallium nitride (GaN) films are used in blue light-emitting diodes (LEDs) and other devices. The properties of gallium nitride films, which are an example of nitride semiconductor films, are significantly affected by their crystallinity. Metal organic chemical vapor deposition (MOCVD) is generally used to grow gallium nitride.

[0012] However, the MOCVD process can pose a problem of environmental impact, as it consumes large amounts of reactive gases. One solution to this problem is to grow gallium nitride using the sputtering method.

[0013] The surface temperature of the target used in sputtering rises due to the incident ions. Even if a cooling mechanism is installed on the backing plate, which is the raw material container that holds the target, the target surface remains hot due to the balance between the thermal conduction within the target and the incident energy of the ions. When using a gallium target, its melting point is approximately 30°C, so the surface of the target melts and becomes liquid. When depositing gallium nitride films, nitrogen gas is added as a Group V raw material in addition to a diluent gas (non-volatile gas) such as argon (Ar) gas and supplied into the processing container, while the gallium target is sputtered with argon gas or the like to grow gallium nitride on the substrate.

[0014] However, during film formation, the nitrogen nitrides the surface of the gallium target, leaving gallium nitride in the liquid target. The formation of this gallium nitride reduces the target's utilization efficiency and increases the frequency of target replacement. Furthermore, if this gallium nitride appears partially on the target surface, it can change the sputtering conditions or the ratio of gallium (Group III source) to nitrogen (Group V source), potentially adversely affecting the stability and reproducibility of crystal growth.

[0015] Therefore, in the sputtering apparatus according to this embodiment, a non-volatile gas such as argon gas is supplied around the gallium target to prevent nitridation (alteration) of the target surface, creating a non-volatile gas atmosphere around the surface of the gallium target. This proposes a method for forming a gallium nitride film by growing gallium nitride on a substrate while suppressing nitridation of the target in a sputtering method using a gallium target. Nitrogen gas is supplied alone or as a mixed gas with argon gas toward the substrate side of the target. The gallium nitride film is an example of a nitride film of a low-melting-point metal or a nitride film of a low-melting-point alloy.

[0016] [Sputtering equipment] A sputtering apparatus 10 according to the present disclosure will be described with reference to Fig. 1. Fig. 1 is a diagram showing the sputtering apparatus 10 according to the embodiment. The sputtering apparatus 10 is a film formation apparatus suitable for forming a gallium nitride (GaN) film. In the sputtering apparatus 10, a wafer holder 13 for holding a wafer W, which is an example of a substrate, and a mounting table 12 on which a backing plate 110 is mounted are provided in a processing chamber 11.

[0017] The backing plate 110 is made of a conductive material such as copper (Cu). The backing plate 110 is shaped like a tray, a dish, a bowl, or the like, and is configured to accommodate a granular raw material of a low-melting point metal or a low-melting point alloy, which is the raw material of the target T. The backing plate 110 is an example of a raw material container that is filled with a granular raw material of a low-melting point metal or a low-melting point alloy.

[0018] The mounting table 12 is supported on the bottom of the processing chamber 11. The wafer holder 13 is suspended from the ceiling of the processing chamber 11. The mounting table 12 and the wafer holder 13 face each other, and a DC power supply 15 is connected between the mounting table 12 and the wafer holder 13 to apply a DC voltage. The DC power supply 15 may apply a DC pulse voltage, which is a rectangular DC voltage. Instead of the DC power supply 15, a high-frequency power supply may be connected to the wafer holder 13, and a high-frequency voltage may be applied from the high-frequency power supply. The DC power supply 15 and the high-frequency power supply are examples of power supplies configured to apply a voltage between the mounting table 12 and the wafer holder 13. The wafer holder 13 is an example of a holding unit configured to hold a substrate, such as a wafer W. An openable and closable shutter 16 is provided in a processing space U between the wafer holder 13 and the mounting table 12.

[0019] The mounting table 12 has a built-in heater 14. The wafer holder 13 has a built-in heater 17. The upper surface of the mounting table 12 and the lower surface of the wafer holder 13 face each other. Therefore, the upper surface of the manufactured target T attached to the mounting table 12 faces the lower surface of the wafer W held by the wafer holder 13. The mounting table 12 functions as a cathode electrode, and the wafer holder 13 functions as an anode electrode. The manufactured target T may be one manufactured inside a processing chamber.

[0020] The sputtering apparatus 10 includes a first gas supply unit 21 and a second gas supply unit 20. The first gas supply unit 21 and the second gas supply unit 20 may be collectively referred to as gas supply units. The processing chamber 11 is provided with a first supply line 22 connected to a first gas hole 24. A nitrogen-containing gas supplied from the first gas supply unit 21 is introduced into the processing chamber 11 through the first gas hole 24. The nitrogen-containing gas is an example of a first gas. The first supply line 22 is provided with a valve 23, and the supply of the first gas is started and stopped by opening and closing the valve 23. In the present disclosure, nitrogen (N2) gas is supplied from the first gas hole 24 in combination with argon (Ar) gas, which is a sputtering gas. The nitrogen gas nitrides the surface of gallium on the wafer W, forming a gallium nitride film. The nitrogen-containing gas (first gas) may be a mixed gas of nitrogen gas and a non-volatile gas, a gas containing nitrogen gas and a non-volatile gas, or nitrogen gas alone.

[0021] Furthermore, the processing chamber 11 is provided with a second supply line 27 connected to a second gas hole 29. A nitrogen-free gas supplied from the second gas supply unit 20 is introduced into the processing chamber 11 through the second gas hole 29. The nitrogen-free gas is an example of the second gas. A valve 28 is provided on the second supply line 27, and the supply of the second gas is started and stopped by opening and closing the valve 28. In the present disclosure, argon gas is supplied through the second gas hole 29. Argon ions generated from the argon gas by the voltage from the DC power supply 15 are incident on the gallium target T, causing gallium sputtering particles to scatter and adhere to the wafer W. The nitrogen-free gas (second gas) is not limited to argon gas, but may be a single non-volatile gas or a combination of multiple non-volatile gases. The non-volatile gas may be an inert gas such as argon gas, xenon (Xe) gas, or krypton (Kr) gas.

[0022] The first gas holes 24 are provided in the sidewall of the processing vessel 11 at a height H1 from the bottom of the processing vessel 11, for example, at equal intervals in the circumferential direction, and introduce the first gas from the outside to the inside of the processing vessel 11 toward the periphery of the wafer holder 13. The second gas holes 29 are provided in the sidewall of the processing vessel 11 at a height H2 (H2

[0023] The second gas holes 29 are closer to the target T than the first gas holes 24. In the example of FIG. 1, the position where the second gas holes 29 are provided in the processing chamber 11 is lower than the position where the first gas holes 24 are provided. As a result, the first gas and the second gas are supplied so that the gas around the wafer W contains more nitrogen than the gas around the target T. In other words, only argon gas, an example of a gas that does not contain nitrogen, is actively supplied around the target T. This prevents nitridation of the surface of the target T. Furthermore, a mixed gas of nitrogen gas and argon gas, an example of a gas that contains nitrogen, is supplied to the surface of the wafer W. This promotes nitridation of gallium attached to the surface of the wafer W. This allows a gallium nitride film to be formed on the wafer W while preventing nitridation of the surface of the target T.

[0024] ​A pump P25 is connected to an exhaust line 31 connected to an exhaust port 26 provided in the processing chamber 11. The pump P25 is an example of an exhaust device that exhausts the inside of the processing chamber 11. The sputtering apparatus 10 is provided with a control unit 30 that controls the operation of the first gas supply unit 21, the second gas supply unit 20, the heaters 14 and 17, the DC power supply 15, the valves 23 and 28, and the pump P25. The control unit 30 is configured, for example, by a computer and includes a central processing unit (CPU) and a storage medium such as a memory. The storage medium stores programs that control various processes executed in the sputtering apparatus 10. The control unit 30 controls the operation of the sputtering apparatus 10 by causing the CPU to execute the programs stored in the storage medium. The control unit 30 also includes an input interface and an output interface. The control unit 30 receives signals from the outside via the input interface and transmits signals to the outside via the output interface.

[0025] The above-mentioned program may be stored in a computer-readable storage medium and installed from that storage medium into the storage medium of the control unit 30. Examples of computer-readable storage media include a hard disk (HD), a flexible disk (FD), an optical disk (OD), a magneto-optical disk (MO), a solid state drive (SSD), and a memory card. The program may also be downloaded from a server via the Internet and installed into the storage medium of the control unit 30.

[0026] The control unit 30 controls the first gas supply unit 21 and the second gas supply unit 20 to supply the first gas and the second gas so that the gas around the wafer W contains more nitrogen gas than the gas around the target T. The control unit 30 controls the DC power supply 15 to apply a DC voltage to draw in argon gas or the like to sputter the target T, causing sputtered particles of gallium to adhere to the wafer W, which are then nitrided with nitrogen gas to form a gallium nitride film.

[0027] [Film forming method] Next, a method for forming a gallium nitride film using a sputtering apparatus 10 according to the present disclosure will be described with reference to Figures 1 and 2. Figure 2 is a flowchart showing the film formation method according to the embodiment. In the present disclosure, the method for forming a gallium film using a gallium target T and nitridation are performed in the same sputtering apparatus 10.

[0028] (Wafer loading; S1) In step S1, the control unit 30 loads the wafer W into the processing chamber 11, places (holds) the loaded wafer W on the wafer holder 13, and adjusts the pressure inside the processing chamber 11 and the temperatures of the backing plate 110 and the wafer holder 13.

[0029] The control unit 30 controls the heater 17 to preheat the wafer holder 13 to a temperature of, for example, 180° C. or more and 220° C. or less, thereby preheating the wafer W.

[0030] The control unit 30 preferably controls the heater 14 to control the temperature of the backing plate 110 to, for example, a temperature of 20° C. or higher and 200° C. or lower. During sputtering (film formation), the temperature of the target T rises due to factors such as the target T being bombarded by argon ions or being exposed to plasma. For this reason, during film formation, a flow path (not shown) may be provided in the mounting table 12, and a refrigerant controlled to a predetermined temperature may be circulated through the flow path to cool the mounting table 12 so that the back surface of the target T is approximately 10° C., thereby adjusting the temperature of the backing plate 110.

[0031] (Second gas supply; S3) 1 is closed, the control unit 30 adjusts the aperture of the valve 28 to supply a gas (second gas) not containing nitrogen gas from the second gas supply unit 20. In the present disclosure, argon gas is supplied from the second gas hole 29 to the periphery of the gallium target T in the processing vessel 11.

[0032] (First gas supply; S5) Next, in step S5, the control unit 30 controls the temperature of the wafer W to 400°C or more and 800°C or less. With the shutter 16 closed, the opening of the valve 23 is adjusted to supply a gas containing nitrogen gas (first gas) from the first gas supply unit 21. In the present disclosure, nitrogen gas and argon gas are supplied at a predetermined ratio from the first gas holes 24 to the periphery of the wafer W in the processing chamber 11. As a specific example of the predetermined ratio, the control unit 30 adjusts the ratio of the flow rate of nitrogen gas to the total flow rate of nitrogen gas and argon gas to 10% or more and 60% or less.

[0033] (Pre-sputtering treatment; S7) Next, in step S7, a pre-sputtering process is performed before the deposition of the gallium nitride film. The control unit 30 applies a DC voltage from the DC power supply 15 between the wafer holder 13 and the mounting table 12. This causes the DC voltage to generate argon ions from the argon gas, which are then incident on the gallium target T and sputter the target T. During the pre-sputtering process, gallium sputtered particles are scattered from the target T, but because the shutter 16 is closed, the sputtered particles do not reach the wafer W. During the pre-sputtering process, the scattering of sputtered particles from the target T stabilizes. For example, the pre-sputtering process may last for 3 to 7 minutes.

[0034] In the pre-sputtering process and the subsequent sputtering process, a radio frequency (RF) voltage may be applied instead of a DC voltage from the DC power supply 15, or a DC voltage may be applied intermittently to perform pulse sputtering.

[0035] (Sputtering process; S9) Next, in step S9, the control unit 30 executes a sputtering process. A gallium nitride film is formed. In the sputtering process, the shutter 16 is opened. As a result, sputtered particles scattered from the target T supply gallium raw material to the surface of the wafer W. As a result, the sputtered gallium particles combine with the nitrogen gas in the processing space U on the surface of the wafer W, forming a gallium nitride film.

[0036] When the deposition of the gallium nitride film is completed, the supply of nitrogen gas and argon gas, the energization of the heater, and the application of DC voltage are stopped to cool the wafer W. When the temperature of the wafer W reaches a predetermined temperature, the wafer W is unloaded from the processing chamber 11, and this process is completed. In this manner, a gallium nitride film is formed on the wafer W.

[0037] When the target T in the backing plate 110 becomes within a predetermined amount or a predetermined thickness, the backing plate 110 is replaced with a backing plate 110 containing granular gallium raw material. Then, a new gallium target T is manufactured and film formation is performed again using the target T by the method shown in Fig. 2. This allows the next target T to be manufactured and film formation to be performed in the same sputtering apparatus 10.

[0038] (Processing vessel 11) The processing vessel 11 is set to a temperature of 1×10 -5 It is preferable to use a processing chamber that can achieve a vacuum of 100 Pa or less in order to prevent impurities generated in the processing chamber 11 from being mixed into the gallium nitride film.

[0039] A cathode electrode (target holder) for attaching a target of a substance that imparts a conductivity type to the gallium nitride film may be provided inside the processing vessel 11. Examples of substances that impart a conductivity type to the gallium nitride film include magnesium (Mg) and silicon (Si). Adding magnesium allows for the formation of a p-type gallium nitride film, and adding silicon allows for the formation of an n-type gallium nitride film.

[0040] A cathode electrode (target holder) for attaching a target of a material containing a gallium nitride film as an alloy crystal may be provided in the processing vessel 11. Examples of materials containing a gallium nitride film as an alloy crystal include aluminum (Al) and indium (In). By adding aluminum, an aluminum gallium nitride (AlGaN) film can be formed, and by adding indium, an indium gallium nitride (InGaN) film can be formed. In other words, the nitride semiconductor film formed according to the present disclosure is not limited to a gallium nitride film. Gallium nitride films, aluminum gallium nitride films, and indium gallium nitride films can be used in electronic devices such as high electron mobility transistors (HEMTs), as well as optical devices such as LEDs.

[0041] In this way, when intermittently sputtering a gallium nitride target, a target of a substance to be mixed into the gallium nitride film to be formed may also be intermittently sputtered. The magnesium, silicon, aluminum, or indium target may be a target of a simple substance of these substances, or may be a target of a compound such as a nitride.

[0042] (Wafer W) It is preferable to use a wafer W having a single-crystal gallium nitride layer on the surface on which the gallium nitride film is to be formed. This is to form a gallium nitride film with good crystallinity. Examples of such a wafer W that can be used include a gallium nitride single-crystal substrate, a sapphire substrate with a gallium nitride single-crystal template, and a silicon substrate with a gallium nitride single-crystal template.

[0043] The above has described a film formation method performed using sputtering apparatus 10, which includes processing vessel 11, mounting table 12 provided within processing vessel 11 and on which backing plate 110 containing gallium target T manufactured within processing vessel 11 is mounted, wafer holder 13 facing mounting table 12 and configured to hold wafer W, first gas supply unit 21 having first gas holes 24 and configured to supply a first gas into processing vessel 11 through first gas holes 24, second gas supply unit 20 having second gas holes 29 located closer to target T than first gas holes 24 and configured to supply a second gas into processing vessel 11 through second gas holes 29, and DC power supply 15 configured to apply a DC voltage between mounting table 12 and wafer holder 13. The film formation method of this embodiment includes the steps of controlling the first gas supply unit 21 and the second gas supply unit 20 to supply a nitrogen-containing gas (first gas) so that the gas around the wafer W contains more nitrogen than the gas around the target T, and supplying a nitrogen-free gas (second gas) so that the gas around the target T contains no nitrogen or only a trace amount of nitrogen, and sputtering the target T using a DC voltage applied from the DC power source 15 to form a gallium nitride film on the wafer W.

[0044] The position where the second gas holes 29 are provided is lower than the position where the first gas holes 24 are provided. Therefore, by supplying a gas that does not contain nitrogen from the second gas holes 29 and a gas that contains nitrogen from the first gas holes 24, it is possible to ensure that the gas around the target T does not contain nitrogen, or that even if it does, it contains only a trace amount of nitrogen. It is also possible to ensure that the gas around the wafer W contains nitrogen. This allows a gallium nitride film to be formed on the wafer W while preventing nitridation of the target T.

[0045] [Another example of a gas hole] Next, another example of the gas supply unit will be described with reference to Figures 3 and 4. Figures 3 and 4 are diagrams showing another example of the gas supply unit of the sputtering apparatus 10 according to the embodiment.

[0046] In the sputtering apparatus 10 of Fig. 3, the positions of the multiple second gas holes 29 are the same as those of the sputtering apparatus 10 of Fig. 1. However, the difference is that the multiple first gas holes 24 penetrate the ceiling of the processing vessel 11 and open from the ceiling toward the wafer holder 13. However, in this case as well, the positions where the second gas holes 29 are provided are the same as those where the first gas holes 24 are provided.

[0047] All of the first gas holes 24 do not necessarily have to be provided in the ceiling portion of the processing vessel 11, but at least some of the first gas holes 24 may be provided in the ceiling portion of the processing vessel 11. For example, some of the first gas holes 24 may be provided in the sidewall of the processing vessel 11 at the positions shown in FIG.

[0048] In the sputtering apparatus 10 of Fig. 4, the positions of the multiple first gas holes 24 are the same as those of the sputtering apparatus 10 of Fig. 1. In contrast, the difference is that the multiple second gas holes 29 penetrate the mounting table 12 and open to the periphery of the backing plate 110. However, in this case as well, the positions where the second gas holes 29 are provided are the same as those where the first gas holes 24 are provided.

[0049] Not all of the second gas holes 29 need to be provided in the mounting table 12, and at least some of the second gas holes 29 may be provided in the mounting table 12. For example, some of the second gas holes 29 may be provided in the sidewall of the processing vessel 11 at positions shown in FIG.

[0050] Furthermore, the first gas hole 24 may be arranged at a position that combines the positions shown in Figures 1 and 3, and the second gas hole 29 may be arranged at a position that combines the positions shown in Figures 1 and 4.

[0051] 1, 3, and 4, as well as a sputtering apparatus 10 that combines two or more of the sputtering apparatuses 10 shown therein, a gas that does not contain nitrogen is supplied from the second gas holes 29, and a gas that contains nitrogen is supplied from the first gas holes 24. This makes it possible to ensure that the gas around the target T does not contain nitrogen, or if it does contain nitrogen, it contains only a trace amount. This allows the target T to be sputtered while preventing nitridation of the target T. Furthermore, a gas that contains nitrogen can be supplied around the wafer W. This causes the sputtered gallium particles to combine with the nitrogen gas in the processing space U on the surface of the wafer W, forming a gallium nitride film.

[0052] The low-melting-point metal may be gallium or indium. The low-melting-point alloy may be an alloy of gallium and indium. The target material may be contained in a source vessel, and at least its surface may be liquid.

[0053] This application claims priority from basic application No. 2021-165051, filed with the Japan Patent Office on October 6, 2021, the entire contents of which are incorporated herein by reference. [Explanation of symbols]

[0054] 10 Sputtering equipment 12 Mounting table 13 Wafer holder 14 Heater 15 DC power supply 110 Backing Plate T Target

Claims

1. A processing vessel; a mounting table provided in the processing vessel and configured to mount a target material of gallium, indium, or an alloy of gallium and indium manufactured in the processing vessel; a holder configured to face the mounting table and hold a substrate; a first gas supply unit having a first gas hole and configured to supply a first gas into the processing vessel through the first gas hole; a second gas supply unit having a second gas hole at a position closer to the target material than the first gas hole and configured to supply a second gas into the processing vessel through the second gas hole; a power supply configured to apply a voltage between the mounting table and the holder; a control unit; At least a portion of the second gas holes is provided in the mounting table, the control unit controls the first gas supply unit and the second gas supply unit to supply the first gas and the second gas such that the gas around the substrate contains more nitrogen than the gas around the target material; A sputtering device that sputters the target material by applying the voltage by controlling the power supply, thereby forming a nitride film of gallium, indium, or an alloy of gallium and indium on the substrate.

2. A processing vessel; a mounting table provided in the processing vessel and configured to mount a target material of gallium, indium, or an alloy of gallium and indium manufactured in the processing vessel; a holder configured to face the mounting table and hold a substrate; a first gas supply unit having a first gas hole and configured to supply a first gas into the processing vessel through the first gas hole; a second gas supply unit having a second gas hole at a position closer to the target material than the first gas hole and configured to supply a second gas into the processing vessel through the second gas hole; a power supply configured to apply a voltage between the mounting table and the holder; a control unit; the first gas is nitrogen gas and argon gas, the control unit controls the first gas supply unit and the second gas supply unit to supply the first gas and the second gas such that the gas around the substrate contains more nitrogen than the gas around the target material; sputtering the target material with the applied voltage by controlling the power supply to form a nitride film of gallium, indium, or an alloy of gallium and indium on the substrate; A sputtering apparatus, wherein the ratio of the flow rate of nitrogen gas to the total flow rate of nitrogen gas and argon gas is adjusted to 10% or more and 60% or less by controlling the first gas supply unit.

3. A processing vessel; a mounting table provided in the processing vessel and configured to mount a target material of gallium, indium, or an alloy of gallium and indium manufactured in the processing vessel; a holder configured to face the mounting table and hold a substrate; a first gas supply unit having a first gas hole and configured to supply a first gas into the processing vessel through the first gas hole; a second gas supply unit having a second gas hole at a position closer to the target material than the first gas hole and configured to supply a second gas into the processing vessel through the second gas hole; a power supply configured to apply a voltage between the mounting table and the holder; a shutter provided at a height position between the first gas hole and the second gas hole; a control unit; the control unit controls the first gas supply unit and the second gas supply unit to supply the first gas and the second gas such that the gas around the substrate contains more nitrogen than the gas around the target material; A sputtering device that sputters the target material by applying the voltage by controlling the power supply, thereby forming a nitride film of gallium, indium, or an alloy of gallium and indium on the substrate.

4. a position where the second gas hole is provided in the processing vessel is lower than a position where the first gas hole is provided; The sputtering apparatus according to any one of claims 1 to 3.

5. the control unit controls the first gas supply unit to supply a gas containing nitrogen as the first gas from the first gas hole, and controls the second gas supply unit to supply a gas not containing nitrogen as the second gas from the second gas hole. The sputtering apparatus according to claim 4 .

6. The target material is contained in a source container, and at least the surface thereof is liquid. The sputtering apparatus according to any one of claims 1 to 3.

7. The first gas is a gas containing nitrogen gas. The sputtering apparatus according to any one of claims 1 to 3.

8. The second gas is an inert gas. The sputtering apparatus according to any one of claims 1 to 3.

9. At least a portion of the first gas holes is provided in a ceiling portion of the processing vessel. The sputtering apparatus according to any one of claims 1 to 3.

10. a heating unit for heating the substrate; the control unit controls the heating unit to adjust the temperature of the substrate to 400° C. or higher and 800° C. or lower. The sputtering apparatus according to any one of claims 1 to 3.

11. A processing vessel; a mounting table provided in the processing vessel and configured to mount a target material of gallium, indium, or an alloy of gallium and indium manufactured in the processing vessel; a holder configured to face the mounting table and hold a substrate; a first gas supply unit having a first gas hole and configured to supply a first gas into the processing vessel through the first gas hole; a second gas supply unit having a second gas hole at a position closer to the target material than the first gas hole and configured to supply a second gas into the processing vessel through the second gas hole; a power supply configured to apply a voltage between the mounting table and the holder; A film formation method performed using a sputtering apparatus having At least a portion of the second gas holes is provided in the mounting table, supplying the first gas and the second gas from the first gas supply unit and the second gas supply unit so that the gas around the substrate contains more nitrogen than the gas around the target material; sputtering the target material with the voltage applied from the power supply to form a nitride film of gallium, indium, or an alloy of gallium and indium on the substrate.

12. A processing vessel; a mounting table provided in the processing vessel and configured to mount a target material of gallium, indium, or an alloy of gallium and indium manufactured in the processing vessel; a holder configured to face the mounting table and hold a substrate; a first gas supply unit having a first gas hole and configured to supply a first gas into the processing vessel through the first gas hole; a second gas supply unit having a second gas hole at a position closer to the target material than the first gas hole and configured to supply a second gas into the processing vessel through the second gas hole; a power supply configured to apply a voltage between the mounting table and the holder; A film formation method performed using a sputtering apparatus having the first gas is nitrogen gas and argon gas, supplying the first gas and the second gas from the first gas supply unit and the second gas supply unit so that the gas around the substrate contains more nitrogen than the gas around the target material; sputtering the target material by the voltage applied from the power supply to form a nitride film of gallium, indium, or an alloy of gallium and indium on the substrate; adjusting a ratio of the flow rate of the nitrogen gas to the total flow rate of the nitrogen gas and the argon gas supplied from the first gas supply unit to 10% or more and 60% or less.

13. A processing vessel; a mounting table provided in the processing vessel and configured to mount a target material of gallium, indium, or an alloy of gallium and indium manufactured in the processing vessel; a holder configured to face the mounting table and hold a substrate; a first gas supply unit having a first gas hole and configured to supply a first gas into the processing vessel through the first gas hole; a second gas supply unit having a second gas hole at a position closer to the target material than the first gas hole and configured to supply a second gas into the processing vessel through the second gas hole; a power supply configured to apply a voltage between the mounting table and the holder; a shutter provided at a height position between the first gas hole and the second gas hole; A film formation method performed using a sputtering apparatus having supplying the first gas and the second gas from the first gas supply unit and the second gas supply unit so that the gas around the substrate contains more nitrogen than the gas around the target material; sputtering the target material with the voltage applied from the power supply to form a nitride film of gallium, indium, or an alloy of gallium and indium on the substrate.

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