Film forming apparatus

Abstract

The present invention provides a film forming apparatus which is capable of suppressing mixing of a process gas into another processing unit. A film forming apparatus 1 comprises: a chamber 20; a rotary table 31 which is provided in the chamber 20 and rotates to circularly convey a workpiece 10 along a circumferential conveyance path L; a film forming unit 40 which deposits a film forming material on the workpiece 10 that is circularly conveyed by the rotary table 31 so as to form a film; a nitriding treatment unit 50 which converts a process gas that contains a nitrogen gas into plasma and nitrides the film forming material deposited on the workpiece 10 that is circularly conveyed by the rotary table 31; an inner wall part 511 which is provided in the nitriding treatment unit 50, defines a treatment space 59 into which the process gas is introduced to perform a plasma treatment, and has an opening 511a that faces the rotary table 31 in a non-contact manner; and a pressure increase plate 511b which is provided at the lower end of the inner wall part 511 and extends from the inner wall part 511 toward the treatment space 59.

Description

Film forming apparatus

[0001] The present invention relates to a film forming apparatus.

[0002] In the manufacturing processes of various products such as semiconductors, displays, or optical disks, for example, thin films such as protective films, conductive films, functional films, or optical films may be formed on a workpiece such as a wafer or a glass substrate. The thin film can be created by repeating film formation that forms a film such as a metal on the workpiece and film processing such as etching, oxidation, or nitridation on the formed film.

[0003] Film formation and film processing can be performed in various ways. One of them is a method by plasma processing. In film formation, for example, a sputtering gas is introduced into a chamber, which is a vacuum vessel in which a target made of a material to form the film is placed, and a voltage is applied to the target. The ions of the sputtering gas generated by the ionization of the sputtering gas are made to collide with the target, and the material knocked out from the target is deposited on the workpiece to form a film. In film processing, a process gas is introduced into a chamber in which electrodes are arranged, and a voltage is applied to the electrodes. The film processing is performed by making the ions of the plasma-processed process gas collide with the film on the workpiece.

[0004] In order to continuously perform such film formation and film processing (hereinafter, both are included as plasma processing), there is a film forming apparatus in which a rotating table is installed inside a single chamber, and a plurality of film forming parts and film processing parts are arranged in the circumferential direction above the ceiling of the chamber, that is, above the rotating table (for example, see Patent Document 1). Thereby, by holding and transporting the workpiece on the rotating table and passing it directly below the film forming part and the film processing part, various films can be formed.

[0005] Japanese Patent Application Laid-Open No. 2018-3152

[0006] As mentioned above, the film deposition apparatus described above has a processing area within the chamber, which is a space for performing plasma processing. Part of this processing area is configured such that the processing area is enclosed in a cylindrical shape by a shielding member (inner wall) that extends from the ceiling of the chamber toward the rotary table. The shielding member is provided to prevent the film deposition material from scattering from the target and adhering to the inner wall of the chamber, and to prevent the sputtering gas and process gas (hereinafter, both collectively referred to as reaction gases) introduced from flowing out of each processing area.

[0007] The side of the shield member opposite the ceiling of the chamber is open, and its edge is positioned close to the workpiece held on the rotary table, leaving a gap to allow the workpiece to pass through. For example, a gap of several millimeters is formed between the edge of the shield member and the workpiece.

[0008] However, due to this gap and the flow of reaction gas between the inside and outside of the shielding member caused by the movement of the rotating turntable and the transported workpiece, it is not possible to completely prevent the leakage of reaction gas.

[0009] Furthermore, a pressure difference exists between the film deposition processing unit and the film processing processing unit. For example, when depositing a dense film, the internal pressure of the film deposition processing unit is generally kept below 1 Pa. In the film processing processing unit, such as oxidation or nitriding, ions from a plasma-generated process gas are collided with the thin film formed on the workpiece in the film deposition processing unit to ensure that the composition ratio of the thin film on the workpiece reaches the target composition ratio. In the film processing processing unit, it is necessary to allow sufficient reaction between the ions from the plasma-generated process gas and the thin film on the workpiece as the workpiece passes through the processing unit. For this reason, the flow rate of the process gas introduced into the film processing processing unit is increased, thereby increasing the amount of plasma-generated process gas ions. As a result, the internal pressure of the film processing processing unit becomes, for example, several Pa to tens of Pa.

[0010] Therefore, in adjacent processing areas, reaction gases from one processing area may flow into the other, or vice versa, resulting in contamination of the reaction gases. In particular, if process gases flow into the processing area where film deposition is performed, the in-plane uniformity of the material of the thin film deposited on the workpiece may be impaired.

[0011] Embodiments of the present invention have been made to solve the above-mentioned problems, and their purpose is to suppress the outflow of process gas from the processing unit.

[0012] To achieve the above objective, the film deposition apparatus of this embodiment comprises: a chamber capable of creating a vacuum inside; a rotary table provided in the chamber that circulates and transports a workpiece along a circumferential transport path by rotating; a film deposition section that plasmaizes sputtering gas and deposits a film deposition material onto the workpiece being circulated and transported by the rotary table to form a film; a nitriding section that plasmaizes a process gas containing nitrogen gas and nitrides the particles of the film deposition material deposited on the workpiece being circulated and transported by the rotary table; an inner wall section provided in the nitriding section section that defines a processing space into which the process gas is introduced and plasma processing is performed, and has an opening that faces the rotary table without contact; and a pressure increasing plate provided at the lower end of the inner wall section and extending from the inner wall section toward the processing space, wherein the pressure increasing plate is connected to the inner wall section and extends around the entire circumference of the inner wall section.

[0013] According to embodiments of the present invention, it is possible to suppress the outflow of process gas from the processing unit.

[0014] This is a schematic perspective plan view showing the configuration of the film deposition apparatus according to the embodiment. This is a cross-sectional view taken along line A-B in Figure 1, showing the internal configuration of the film deposition apparatus as seen from the side. This is a cross-sectional view taken along line A-C in Figure 1, showing the internal configuration of the film deposition apparatus as seen from the side. This is an enlarged cross-sectional view of the nitriding section. This is an enlarged view of the dotted circled portion in Figure 4. (A) is a perspective plan view showing the nitriding section, and (B) is a cross-sectional view taken along line D-D in (A). This is a flowchart of the processing by the film deposition apparatus according to the embodiment. These are graphs showing the gas supply and outflow rates for Examples 1 to 10 and comparative examples. (A) is a graph showing the relationship between the aperture ratio and the outflow rate per unit area, and (B) is an enlarged graph of the horizontal axis of (A) for the aperture ratio range of 100% to 20%. This is a graph showing the outflow rate and supply rate per unit area in the aperture ratio range of 100% to 20%. This is an enlarged cross-sectional view of the nitriding section showing a modified example in which no exhaust space is provided around the nitriding section. A modified example in which an outflow prevention plate is provided on the outer wall, where (A) is an enlarged cross-sectional view of the nitriding treatment area when the outflow prevention plate extends in the opposite direction to the inner wall, and (B) is an enlarged cross-sectional view of the nitriding treatment area when the outflow prevention plate extends in the direction to the inner wall. A modified example in which a pressure increasing plate extends diagonally, an enlarged view showing the configuration of Figure 5. A modified example in which an inclined portion is provided on the inner wall and / or outer wall, where (A) is an enlarged view of the nitriding treatment area with an inclined portion provided only on the inner wall, and (B) is an enlarged view of the nitriding treatment area with inclined portions provided on both the inner and outer walls. A modified example in which an exhaust space is provided in the film deposition area adjacent to the nitriding treatment area, where (A) is a schematic perspective plan view showing the configuration of the film deposition apparatus, and (B) is an enlarged cross-sectional view of the film deposition area.

[0015] Various embodiments of this disclosure are described below with reference to the accompanying drawings. Many specific details are provided in the following detailed description to ensure a full understanding of this disclosure. However, it will be obvious to those skilled in the art that this disclosure can be made without such detailed descriptions. In other examples, known methods, procedures, systems, and components are not described in detail to avoid complicating the various embodiments. Note that the drawings are schematic diagrams, and the sizes and proportions of parts may be exaggerated for ease of understanding. Furthermore, the present invention is not limited to the embodiments described below.

[0016] [Overview] The film deposition apparatus 1 shown in Figures 1 to 3 comprises multiple processing units (PUs) that perform plasma processing on a workpiece 10 transported by a rotary table 31 by introducing a reaction gas and turning it into plasma. At least one of the processing units (PUs) is a film deposition unit 40 that deposits a film deposition material onto the workpiece 10 by sputtering to form a film. In this embodiment, an example is shown in which a GaN (gallium nitride) film is formed on the workpiece 10 by the film deposition apparatus 1. Therefore, the film deposition unit 40 forms a GaN film on the workpiece 10, which is the target of film deposition, by sputtering.

[0017] Furthermore, the processing unit PU includes a nitriding processing unit 50 that nitrides the film formed on the workpiece 10 by plasma treatment. In this embodiment, the nitriding processing unit 50 has a pressure increasing plate 511b at the lower end of the inner wall portion 511 that defines the processing space 59. When the same flow rate of gas is introduced into the processing space 59, the pressure inside the processing space 59 increases because the nitriding processing unit 50 has a pressure increasing plate 511b. In other words, the pressure increasing plate 511b allows the processing space 59 to reach a predetermined pressure with a small amount of gas supply. In the following description, the reaction gas used in the film formation unit 40 will be referred to as sputtering gas G1, and the reaction gas used in the nitriding processing unit 50 will be referred to as process gas G2.

[0018] The workpiece 10 to be deposited is, for example, a silicon (Si) wafer, a silicon carbide (SiC) wafer, a sapphire substrate, a glass substrate, etc. The workpiece 10 is placed on a tray 11 and transported. The tray 11 is a plate-shaped object held on a rotary table 31.

[0019] The film deposition apparatus 1 includes a chamber 20, a transport unit 30, a film deposition unit 40, a nitriding unit 50, an exhaust space 60, a surface treatment unit 70, a transfer chamber 80, a cooling chamber 90, and a control device 100. The chamber 20 is a container capable of creating a vacuum inside. The chamber 20 is cylindrical in shape, and its interior is divided into multiple compartments. In this embodiment, as shown in Figure 1, it is divided into five compartments separated by a partition 22. The film deposition unit 40 is located in three compartments separated by the partition 22 and divided in a fan shape. The nitriding unit 50 and the surface treatment unit 70 are located in the compartments other than the one where the film deposition unit 40 is located.

[0020] The film deposition unit 40 includes a target 42 made of a film deposition material containing GaN and a plasma generator P1 that converts sputtering gas G1 introduced between the target 42 and the rotary table 31 into plasma. The unit deposits particles of the film deposition material onto a workpiece 10 that is being circulated and transported by the rotary table 31 by sputtering.

[0021] The nitriding section 50 comprises a processing space 59 surrounded by an inner wall portion 511 that is not in contact with the rotary table 31, and nitrogen (N) introduced into the processing space 59. ２ The system includes a plasma generator P2 that converts a process gas G2 containing ) into plasma, and nitrides particles of the film deposition material deposited by the film deposition unit 40 onto a workpiece 10 that is being circulated and transported by a rotary table 31.

[0022] The workpiece 10 circulates around the chamber 20 multiple times along its circumference, alternately passing through the film formation section 40 and the nitriding section 50. On the workpiece 10, the formation of a GaN film and the nitriding of the non-nitrided Ga in the GaN film are repeated alternately, and a GaN film of the desired thickness grows.

[0023] Furthermore, the reason for using a GaN-containing material as the target 42 and then providing a nitriding treatment 50 to nitride the Ga of the GaN film formed by the deposition process is as follows: Since Ga has a low melting point and is in a liquid state at room temperature and pressure, it is necessary to include nitrogen in order to make the target 42 a solid.

[0024] In order to improve the film deposition rate, DC discharge sputtering is preferred over RF discharge. However, if the target 42 contains a large amount of nitrogen, the surface becomes an insulator, and in such cases, DC discharge may not occur on the target 42 whose surface has become an insulator.

[0025] In other words, if DC discharge sputtering is adopted considering the film deposition rate, there is a limit to the amount of nitrogen that can be included in the GaN target 42. Consequently, the nitridation of Ga in the target 42 remains insufficient, and the GaN-containing target 42 contains Ga atoms that lack bonds with N (nitrogen) atoms.

[0026] When a film is deposited using such a target 42, the deposited GaN film has a low nitrogen content, resulting in nitrogen vacancies (non-nitrided states), poor crystallinity of the film, and impaired flatness. Therefore, it is necessary to supplement the missing nitrogen. One might consider adding nitrogen gas to the sputtering gas introduced into the film deposition unit 40, but this would cause the surface of the target 42 to be nitrided, making the surface an insulator. Consequently, the film deposition unit 40 cannot add nitrogen gas to the sputtering gas to supplement the missing nitrogen.

[0027] Therefore, in this embodiment, in order to replenish the insufficient nitrogen in the GaN film formed in the film formation unit 40, nitriding is performed in the nitriding treatment unit 50 after film formation in the film formation unit 40. As a result of this nitriding treatment during film formation, the nitrogen content of the film on the workpiece 10 can be increased, and a GaN film without nitrogen defects can be formed.

[0028] [Chamber] As shown in Figure 2, the chamber 20 is a container capable of creating a vacuum inside. The chamber 20 is a hollow cylindrical shape, and its interior is divided into multiple compartments. The chamber 20 is formed by being surrounded by a disc-shaped top surface 20a, a disc-shaped bottom surface 20b, and an annular side surface 20c. The partition 22 is a rectangular wall plate arranged radially from the center of the cylindrical shape, extending from the top surface 20a toward the bottom surface 20b, but not reaching the bottom surface 20b. That is, a cylindrical space is secured on the bottom surface 20b side.

[0029] A rotary table 31 for transporting the workpiece 10 is positioned in this cylindrical space. The lower end of the partition 22 faces the surface on which the workpiece 10 is placed on the rotary table 31, leaving a gap for the workpiece 10 to pass through. The partition 22 separates the processing space 41 in which the workpiece 10 is processed by the film deposition unit 40. In other words, the film deposition unit 40 has a processing space 41 that is smaller than the chamber 20. The partition 22 suppresses the diffusion of the sputtering gas G1 from the film deposition unit 40 into the chamber 20. In the film deposition unit 40, since it is only necessary to adjust the pressure in the processing space 41 which is smaller than the chamber 20, pressure adjustment can be easily performed and the plasma discharge can be stabilized.

[0030] The chamber 20 is provided with an exhaust port 21. An exhaust unit 23 is connected to the exhaust port 21. The exhaust unit 23 includes piping and a pump, valves, etc. (not shown). By exhausting through the exhaust port 21 using the exhaust unit 23, the pressure inside the chamber 20 can be reduced to a vacuum. To keep the oxygen concentration low, the exhaust unit 23 exhausts until, for example, the vacuum level reaches 10⁻⁴ Pa.

[0031] [Conveying Unit] The conveying unit 30 includes a rotary table 31 and a motor 32. The rotary table 31 is provided inside the chamber 20 and rotates to circulate and convey the workpieces 10 along the circumferential conveying path L. The rotary table 31 in this embodiment holds and conveys multiple workpieces 10. The rotary table 31 is a disc-shaped member placed inside the chamber 20 and is wide enough so as not to come into contact with the inside of the side surface 20c.

[0032] The rotary table 31 is supported by a rotating shaft 33, which is coaxial with its center, via a fastening member. The rotating shaft 33 airtightly penetrates the bottom surface 20b of the chamber 20 and protrudes to the outside. The motor 32 is located outside the chamber 20 and rotates the rotating shaft 33 via a coupling member, thereby continuously rotating the rotary table 31 at a predetermined rotational speed. The rotary table 31 rotates at a speed of, for example, 1 to 150 rpm.

[0033] As shown in Figure 1, the rotary table 31 is provided with a film deposition area FA on which multiple workpieces 10 are deposited. The film deposition area FA is an annular region that, when viewed from the planar direction, is the area of ​​the rotary table 31 other than the rotation axis 33, and is opposite the film deposition section 40 and the nitriding section 50. Within the film deposition area FA, holding areas HA for holding individual workpieces 10 are provided at equal intervals in the circumferential direction.

[0034] The holding area HA is provided with holding parts such as grooves, holes, protrusions, jigs, and holders, and the tray 11 on which the workpiece 10 is placed is held by a mechanical chuck and an adhesive chuck. Multiple workpieces 10 are arranged on the tray 11, for example, and six holding areas HA are arranged on the rotary table 31 at 60° intervals. In other words, the film deposition apparatus 1 can deposit films on multiple workpieces 10 held in multiple holding areas HA all at once, making it highly productive. Note that the tray 11 may be omitted, and the workpieces 10 may be held directly in the holding area HA of the rotary table 31. Although not shown in the figures, the holding area HA is also provided with a heating section for heating the workpieces 10. The heating section can use a heater that generates heat when electricity is applied. Furthermore, the tray 11 and workpieces 10 in the holding area HA are arranged so that their upper surfaces are flush with the upper surface of the rotary table 31.

[0035] [Film Deposition Section] The film deposition section 40 generates plasma and exposes a target 42, which is made of film deposition material, to the plasma. As a result, the film deposition section 40 deposits particles (hereinafter referred to as sputtered particles) that make up the target 42, which are knocked out by colliding ions contained in the plasma with the target 42, onto the workpiece 10 to perform film deposition.

[0036] As shown in Figure 2, the film deposition unit 40 includes a plasma generator P1 that converts sputtering gas G1 introduced between a target 42 made of film deposition material and a rotary table 31 into plasma. The plasma generator P1 consists of a sputtering source composed of a target 42, a backing plate 43, and electrodes 44, a power supply unit 46, and a sputtering gas introduction unit 49.

[0037] The target 42 is a plate-shaped member made of a film-forming material that is deposited on the workpiece 10 to form a film. The target 42 is provided at a distance from the transport path L of the workpiece 10 placed on the rotary table 31. The surface of the target 42 is held on the top surface 20a of the chamber 20 so as to face the workpiece 10 placed on the rotary table 31. One or more targets 42 are provided for each film-forming section 40; in this embodiment, three are provided, and the three targets 42 are positioned to be aligned on the vertices of a triangle in a plan view.

[0038] The backing plate 43 is a support member that holds the target 42. The target 42 is held on the top surface 20a of the chamber 20 via the backing plate 43. This backing plate 43 holds each target 42 individually. The electrode 44 is a conductive member for applying power to each target 42 individually from outside the chamber 20 and is electrically connected to the target 42. The power applied to each target 42 can be changed individually. In addition, the sputtering source is appropriately equipped with magnets, cooling mechanisms, etc., as needed.

[0039] The power supply unit 46 is, for example, a DC power supply that generates high voltage and is electrically connected to the electrode 44. The power supply unit 46 applies the generated power to the target 42 through the electrode 44. The rotary table 31 is at the same potential as the grounded chamber 20, and by applying a high voltage to the target 42, a potential difference is generated between the target 42 and the rotary table 31.

[0040] As shown in Figure 2, the sputtering gas introduction unit 49 introduces sputtering gas G1 into the chamber 20. The sputtering gas introduction unit 49 has a sputtering gas G1 supply source such as a cylinder (not shown), piping 48, and a gas inlet 47. The piping 48 is connected to the sputtering gas G1 supply source, penetrates the chamber 20 airtightly, extends into the interior of the chamber 20, and its end opens as the gas inlet 47. In this embodiment, the sputtering gas introduction unit 49 introduces sputtering gas G1 into the processing space 41 such that the pressure in the processing space 41 is, for example, 0.3 Pa or more and 1.0 Pa or less.

[0041] The gas inlet 47 opens between the rotary table 31 and the target 42, and introduces the sputtering gas G1 for film formation into the processing space 41 formed between the rotary table 31 and the target 42. As the sputtering gas G1, a noble gas can be adopted, and argon (Ar) gas or the like is suitable. The sputtering gas G1 is a gas that does not contain nitrogen (N2), and can be an argon (Ar) single gas. Note that the noble gas does not react with the particles of the film-forming material. For example, even when the sputtering gas G1 is an Ar single gas, the sputtering gas G1 is included in the reaction gas. That is, the reaction gas includes a gas that does not react with other substances by itself but indirectly contributes to the reaction of other substances, such as a noble gas.

[0042] In such a film-forming unit 40, when the sputtering gas G1 is introduced from the sputtering gas introduction unit 49 and the power supply unit 46 applies a high voltage to the target 42 through the electrode 44, the sputtering gas G1 introduced into the processing space 41 formed between the rotary table 31 and the target 42 is plasmaized, and active species such as ions are generated. The ions in the plasma collide with the target 42 and knock out sputtering particles.

[0043] Further, the workpiece 10 circulated and conveyed by the rotary table 31 passes through this processing space 41. The knocked-out sputtering particles are deposited on the workpiece 10 when the workpiece 10 passes through the processing space 41, and a film composed of sputtering particles is formed on the workpiece 10. The workpiece 10 is circulated and conveyed by the rotary table 31, and the film-forming process is performed by repeatedly passing through this processing space 41. The film thickness of the film deposited each time the film-forming unit 40 passes once depends on the processing rate of the nitriding unit 50, but for example, it is preferably a thin film of about 1 to 2 atomic levels (5 nm or less). By circulating and conveying the workpiece 10 a plurality of times, the thickness of the film increases, and a film with a predetermined film thickness is formed on the workpiece 10.

[0044] In this embodiment, the film forming apparatus 1 includes a plurality (here, three) of film forming units 40, and the film forming units 40 are provided one by one in three compartments partitioned by the partitioning portion 22. The plurality of film forming units 40 form a film composed of layers of a plurality of film forming materials by selectively depositing the film forming materials. In particular, in this embodiment, it includes sputtering sources corresponding to different types of film forming materials, and forms a film composed of layers of a plurality of types of film forming materials by selectively depositing the film forming materials. Including sputtering sources corresponding to different types of film forming materials means that even when the film forming materials of all the film forming units 40 are different, or when the film forming materials are common among the plurality of film forming units 40 but different from those of other film forming units 40. Selectively depositing the film forming materials one by one means that while the film forming unit 40 of any one type of film forming material is performing film formation, the film forming units 40 of other film forming materials do not perform film formation.

[0045] In this embodiment, the film forming materials constituting the targets 42 of the two film forming units 40 are materials containing Ga and GaN, and the targets 42 serve as a supply source of sputtered particles containing Ga atoms to be deposited on the workpiece 10. The target 42 contains GaN and incomplete GaN lacking nitrogen, that is, Ga atoms with a defective bond with N (nitrogen).

[0046] The film forming material constituting the target 42 of one film forming unit 40 is a material containing Al, and the target 42 serves as a supply source of sputtered particles containing Al atoms to be deposited on the workpiece 10. As long as the target 42 for sputtering can supply sputtered particles containing Ga atoms and sputtered particles containing Al atoms, it is allowed to contain elements other than Ga, Al, and N (nitrogen).

[0047] As shown in FIG. 1, in order to distinguish between the two types of film forming units 40, the two film forming units 40 having the targets 42 made of materials containing Ga and GaN are designated as film forming unit 40A (GaN film forming unit), and the film forming unit 40 having the target 42 made of a material containing Al is designated as film forming unit 40B (Al film forming unit).

[0048] [Nitriding Treatment Section] The nitriding treatment section 50 generates inductively coupled plasma in a processing space 59 into which process gas G2 containing nitrogen gas is introduced. That is, the nitriding treatment section 50 generates chemical species by plasmaizing nitrogen gas. Nitrogen atoms contained in the generated chemical species collide with the film containing Ga atoms and the film containing Al atoms that have been deposited on the workpiece 10 by the film deposition section 40, and bond with Ga atoms in the film containing Ga atoms that lack a bond with nitrogen, and with Al atoms in the film containing Al atoms. As a result, GaN films and AlN films without nitrogen defects can be obtained.

[0049] As shown in Figure 2, the nitriding treatment unit 50 has a plasma generator P2 which is composed of an inner wall portion 511, a cover portion 512, a window member 52, an antenna 53, an RF power supply 54, a matching box 55, and a process gas introduction portion 58.

[0050] The inner wall portion 511 is a member that surrounds the processing space 59. In other words, the inner wall portion 511 is provided in the nitriding processing unit 50 and defines the processing space 59 in which the process gas G2 is introduced and plasma processing is performed. The inner wall portion 511 is cylindrical in shape, as shown in Figures 1 and 2. One end of the inner wall portion 511 is fitted into an opening 21b provided in the top surface 20a of the chamber 20. In other words, one end of the inner wall portion 511 is provided in the opening 21b of the chamber 20.

[0051] The inner wall portion 511 has an opening 511a at its other end that faces the rotary table 31 without contact. The inner wall portion 511 protrudes into the internal space of the chamber 20 such that the opening 511a at the other end faces the rotary table 31. However, the inner wall portion 511 is not in contact with the rotary table 31. Furthermore, the inner wall portion 511 is in contact with the side surface 20c of the chamber 20. As a result, the space around the outer circumference of the inner wall portion 511 is partitioned by the side surface 20c of the chamber 20. It is not necessarily required that the inner wall portion 511 and the side surface 20c be in direct contact; the space around the outer circumference of the inner wall portion 511 may be partitioned by interposing a partition member between the outer circumference of the inner wall portion 511 and the side surface 20c of the chamber 20. The inner wall portion 511 is not limited to a cylindrical shape. For example, it may be a cylindrical shape with the opening 511a being fan-shaped or elliptical.

[0052] The inner wall portion 511 has a pressure-increasing plate 511b. The pressure-increasing plate 511b is provided at the lower end of the inner wall portion 511. The lower end of the inner wall portion 511 is the end of the inner wall portion 511 where the opening 511a is formed. The pressure-increasing plate 511b is a flat, ring-shaped plate with a circular hole 511c in the center. The ring shape is not limited to a perfect circle, and includes perfect circles, ellipses, sectors, squares, etc. Furthermore, the pressure-increasing plate 511b may have a different shape from the opening 511a of the inner wall portion 511, or it may have a similar shape. In addition, the circular shape of the hole 511c includes perfect circles and ellipses, and the shape of the hole 511c is not limited to a perfect circle, but includes sectors, squares, etc. The pressure-increasing plate 511b is provided around the entire circumference of the lower end of the inner wall portion 511 and extends from the inner surface of the inner wall portion 511 toward the processing space 59.

[0053] The extension length of the pressure-increasing plate 511b is uniform around its entire circumference. In other words, the path from the inside to the outside of the inner wall portion 511 of the nitriding treatment unit 50 between the lower surface of the pressure-increasing plate 511b and the rotary table 31 is equal. The extension length of the pressure-increasing plate 511b is the length extending from one of the continuous points forming the end face of the pressure-increasing plate 511b that connects to the inner wall portion 511 toward the center line C of the processing space 59 (see Figure 4). In this embodiment, the extension length of the pressure-increasing plate 511b is the length from the end face of the pressure-increasing plate 511b that connects to the inner wall portion 511 to the inner surface of the hole 511c. The extended end surface 511d is one of the continuous points forming the inner surface of the hole 511c or a surface. That is, the inner surface of the hole 511c is formed by a collection of continuous extended end surfaces 511d. The length of the line connecting one of the continuous points forming the end face of the pressure-increasing plate 511b that connects to the inner wall portion 511 to the nearest extending end face 511d is equal to the extension length of the pressure-increasing plate 511b.

[0054] The area of ​​the holes 511c in the pressure-increasing plate 511b relative to the area of ​​the opening 511a in the inner wall portion 511 is preferably 45% to 95%. The area of ​​the holes 511c in the pressure-increasing plate 511b relative to the area of ​​the opening 511a in the inner wall portion 511 is also called the opening ratio. By setting the opening ratio to 45% to 95%, the process gas G2 can be retained in the processing space 59 more effectively than when the pressure-increasing plate 511b is not provided, thereby suppressing the outflow rate of the process gas G2.

[0055] The area of ​​the hole 511c in the pressure increasing plate 511b can be determined, for example, by calculating the radius from the diameter D1 of the hole 511c in the pressure increasing plate 511b shown in Figure 4 (the line that passes from one extended end surface 511d of the pressure increasing plate 511b through the center of the hole 511c to the other extended end surface 511d). The area of ​​the opening 511a in the inner wall portion 511 can be determined, for example, by calculating the radius from the diameter D2 of the opening 511a in the inner wall portion 511 shown in Figure 4 (the diameter of the opening 511a in the inner wall portion 511 when the pressure increasing plate 511b is not installed). The opening ratio can then be determined based on the area of ​​the hole 511c in the pressure increasing plate 511b and the area of ​​the opening 511a in the inner wall portion 511 using the following formula. If the pressure increasing plate 511b is not provided, the size of the hole 511c in the pressure increasing plate 511b and the opening 511a in the inner wall portion 511 will be the same, and the opening ratio will be 100%. Opening ratio = Area of ​​hole 511c in the pressure increasing plate 511b / Area of ​​opening 511a in the inner wall portion 511 × 100

[0056] Furthermore, it is even more preferable that the opening ratio be between 50% and 95%. By setting the opening ratio to between 50% and 95%, the amount of process gas G2 flowing out from the nitriding treatment unit 50 can be further reduced compared to when the pressure increasing plate 511b is not provided, and the supply efficiency for supplying process gas G2 to bring the pressure in the processing space 59 to a predetermined pressure can be improved.

[0057] The lower limit of the aperture ratio can be appropriately adjusted by the processing rate in the nitriding treatment unit 50. For example, in the case of a GaN film, the processing rate should be such that the thin film of GaN (non-nitrided state) that is sputter-deposited on the workpiece 10 and lacking nitrogen is sufficiently nitrided. Furthermore, the amount of outflow from the nitriding treatment unit 50 should not affect the film deposition in the deposition area, and this can be determined in advance through experiments, etc., and an appropriate aperture ratio can be set based on the processing rate. In addition, the extension length of the pressure increasing plate 511b does not have to be the same in a part of the entire circumference. In this case, the circumferential extension amount of the pressure increasing plate 511b can be adjusted to obtain the area of ​​the holes 511c in the pressure increasing plate 511b that results in the desired aperture ratio.

[0058] The pressure-increasing plate 511b is formed from the same material as the inner wall portion 511. The pressure-increasing plate 511b is connected to the inner wall portion 511 without any other members interposed between them, and is formed integrally with the inner wall portion 511. Being integrally with the inner wall portion 511 means that the pressure-increasing plate 511b is continuously connected to the inner wall portion 511. By forming the inner wall portion 511 and the pressure-increasing plate 511b integrally, it is possible to suppress the outflow of process gas G2 from the nitriding treatment portion 50. However, the connection between the pressure-increasing plate 511b and the inner wall portion 511 includes not only cases where they are formed integrally, but also cases where the pressure-increasing plate 511b and the inner wall portion 511 are joined by welding, diffusion bonding, soldering, etc.

[0059] As shown in Figure 5, the pressure increasing plate 511b extends perpendicularly to the inner wall portion 511. That is, the pressure increasing plate 511b extends parallel to the workpiece holding surface of the rotary table 31, and the lower surface of the pressure increasing plate 511b faces the holding surface of the rotary table 31. It is preferable that the distance L1, which is the distance from the lower end of the extended tip surface 511d of the pressure increasing plate 511b to the surface of the rotary table 31, is less than or equal to the distance L2, which is the distance from the lower end of the inner wall portion 511 to the surface of the rotary table 31. The lower end of the extended tip surface 511d of the pressure increasing plate 511b refers to the end of the extended tip surface 511d on the rotary table 31 side. In this embodiment, distance L1 and distance L2 are the same length. By doing so, the process gas G2 can be effectively retained in the processing space 59, and the pressure in the processing space 59 can be increased with a small flow rate.

[0060] The cover portion 512 is a cylindrical member. As shown in Figure 2, the cover portion 512 is attached so as to protrude outward and upward from the top surface 20a of the chamber 20, with one end aligned with the opening 21b of the chamber 20. The window member 52 is a flat plate of dielectric material such as quartz, with a horizontal cross-section approximately similar to that of the cover portion 512. This window member 52 is provided inside the cover portion 512 so as to close the opening 21b, and separates the processing space 59 into which the process gas G2 containing nitrogen gas from the chamber 20 is introduced from the inside of the cover portion 512. At this time, it is necessary to suppress oxidation caused by the inflow of oxygen into the processing space 59. For example, the required oxygen concentration is 10 １９ (atom / cm ３ ) is very low. To address this, the surface of the window member 52 is coated. For example, the surface of the window member 52 is coated with Y ２ O ３ By applying a coating with yttrium oxide, the wear of the window member 52 by plasma can be suppressed, while the release of oxygen from the surface of the window member 52 can be inhibited, thereby maintaining a low oxygen concentration.

[0061] The processing space 59 is formed in the nitriding processing unit 50 by being surrounded by the rotary table 31 and the inner wall portion 511. The nitriding process is performed by repeatedly passing the workpiece 10, which is circulated and transported by the rotary table 31, through this processing space 59.

[0062] The antenna 53 is a conductor wound in a coil shape and is located in the internal space of the cover portion 512, which is isolated from the processing space 59 in the chamber 20 by the window member 52. When an alternating current is passed through it, it generates an electric field. It is desirable that the antenna 53 be located near the window member 52 so that the electric field generated from the antenna 53 is efficiently introduced into the processing space 59 via the window member 52. An RF power supply 54, which applies a high-frequency voltage, is connected to the antenna 53. A matching box 55, which is a matching circuit, is connected in series to the output side of the RF power supply 54. The matching box 55 stabilizes the plasma discharge by matching the impedance of the input and output sides.

[0063] As shown in Figure 2, the process gas introduction section 58 introduces process gas G2 containing nitrogen gas into the processing space 59. The process gas introduction section 58 has a supply source of process gas G2, such as a cylinder (not shown), piping 57, and a gas inlet 56. The piping 57 is connected to the supply source of process gas G2, penetrates the chamber 20 while hermetically sealing it, and extends into the interior of the chamber 20, with its end opening as the gas inlet 56.

[0064] The gas inlet 56 opens into the processing space 59 between the window member 52 and the rotary table 31, and introduces the process gas G2. A noble gas can be used as the process gas G2, with argon gas, nitrogen gas, etc., being preferred. Furthermore, it is preferable that the process gas G2 is supplied at a rate that maintains the pressure in the processing space 59 at 5 Pa.

[0065] The inner wall portion 511 partitions the processing space 59 in which the nitriding treatment is performed by the nitriding treatment unit 50. In other words, the nitriding treatment unit 50 has a processing space 59 that is smaller than the chamber 20 and separated from the processing space 41. Since it is only necessary to adjust the pressure in the processing space 59, which is partitioned into a space smaller than the chamber 20, pressure adjustment can be easily performed, and the plasma discharge can be stabilized.

[0066] In this nitriding treatment unit 50, a high-frequency voltage is applied from the RF power supply 54 to the antenna 53. This causes a high-frequency current to flow through the antenna 53, generating an electric field due to electromagnetic induction. The electric field is generated in the processing space 59 through the window member 52, and inductively coupled plasma is generated in the process gas G2. At this time, nitrogen species containing nitrogen atoms are generated and collide with the film on the workpiece 10, bonding with the atoms constituting the film. As a result, the film on the workpiece is nitrided, and a nitrided film is formed as a compound film.

[0067] Thus, the nitriding unit 50 has the function of generating a compound film by creating a plasma of nitrogen gas to generate chemical species containing nitrogen atoms and chemically reacting them with the film formed on the workpiece 10. In the nitriding unit 50, by utilizing inductively coupled plasma with a high plasma density, it is possible to efficiently chemically react the chemical species in the plasma with the film formed on the workpiece 10 by the film deposition unit 40 to generate a compound film.

[0068] [Exhaust Space] The exhaust space 60 is provided around the nitriding processing unit 50. The exhaust space 60 is formed by a double wall consisting of an outer wall 61 that covers the inner wall 511 that defines the processing space 59 of the nitriding processing unit 50 with a gap in between, and an inner wall 511 that has an opening 61a facing the rotary table 31 without contact, with the opposite side of the opening 61a closed. Process gas G2 that leaks out from the processing space 59 through the hole 511c of the pressure increasing plate 511b and the gap between the lower surface of the pressure increasing plate 511b and the rotary table 31 flows into the exhaust space 60 provided on the outer circumference of the inner wall 511 in this way.

[0069] The outer wall portion 61 is a U-shaped plate-like body that covers the inner wall portion 511 in a plan view (see Figure 1). The outer wall portion 61 is curved to follow the side of the inner wall portion 511 on the side of the rotation axis 33 (opposite to the side surface 20c), and both ends of the outer wall portion 61 are in contact with the side surface 20c of the chamber 20. The both ends of the outer wall portion 61 are the two ends of the U-shape, that is, the two ends on the open side of the U-shape. These are the end faces in the vertical direction of those ends, that is, in the direction perpendicular to the rotation plane of the rotary table 31 (parallel to the rotation axis 33).

[0070] Furthermore, the outer wall portion 61 covers the inner wall portion 511 in a side view (see Figure 2). The end of the outer wall portion 61 on the side of the opening 61a is at the same height as, or at the height that covers, the end of the inner wall portion 511 on the side of the opening 511a. The side of the outer wall portion 61 opposite to the opening 61a is closed by a plate parallel to the rotation plane of the rotary table 31. However, the upper part of the outer wall portion 61 may be closed by the top surface 20a of the chamber 20.

[0071] As described above, the space around the inner wall portion 511 is partitioned by the outer wall portion 61, which covers it with a gap, thereby forming the exhaust space 60. In addition, a part of the inner wall portion 511 is in contact with the side surface 20c of the chamber 20. This contact portion partitions the exhaust space 60 from the entire circumference of the inner wall portion 511 in a plan view. As a result, the exhaust space 60 has two ends from which the process gas G2 does not circulate around the entire circumference of the inner wall portion 511 in a plan view. More specifically, an exhaust space 60 with a U-shaped horizontal cross-section is formed around the inner wall portion 511, and the side surface 20c of the chamber 20 becomes the two ends of the exhaust space 60.

[0072] The distance d1 between the opening 511a of the inner wall portion 511 and the surface of the rotary table 31, and the distance d2 between the opening 61a of the outer wall portion 61 and the surface of the rotary table 31, as shown in Figure 2, are distances that do not obstruct the rotation of the rotary table 31. Furthermore, the end of the outer wall portion 61 facing the rotary table 31 is closer to the rotary table 31 than the end of the inner wall portion 511 facing the rotary table 31. In other words, the lower end (opening 61a) of the outer wall portion 61 is located closer to the surface of the rotary table 31 than the lower end (opening 511a) of the inner wall portion 511. However, this is not limited to this, and the distances d1 and d2 may be made equal.

[0073] As shown in Figures 6(A) and 6(B), an exhaust port 62 is provided in the exhaust space 60. The exhaust port 62 is connected to an exhaust device 63 that communicates with the exhaust space 60 and sucks in process gas G2 leaking from the gap between the lower surface of the pressure increasing plate 511b and the rotary table 31, and exhausts it to the outside of the chamber 20. As the exhaust device 63, for example, a turbopump can be used which has turbine-type blades, a movable blade and a fixed blade, and generates airflow by rotating the movable blade at high speed. Multiple exhaust ports 62 are provided. In this embodiment, the exhaust ports 62 are formed on both sides 20c of the chamber 20 corresponding to both ends of the exhaust space 60. The exhaust volume is preferably, for example, 300 L / min or more. If two exhaust devices 63 are used, each should have a volume of 150 L / min or more.

[0074] [Surface Treatment Section] The surface treatment section 70 processes the surface of the workpiece 10 being transported in circulation by the rotary table 31 and the surface of the film deposited by the film deposition section 40. The processing performed by the surface treatment section 70 is the removal of oxide film from the surface of the workpiece 10 before the film is deposited by the film deposition section 40, or the flattening of the surface of the film in the process of forming on the workpiece. The film in the process of forming on the workpiece 10 is the film up to the point where it reaches the desired thickness to be formed on the workpiece 10.

[0075] Specifically, this refers to a compound film on a workpiece 10 that has been treated by the nitriding treatment unit 50, or a film on a workpiece 10 formed by the film formation unit 40. In other words, the transport unit 30 circulates the workpiece 10 so that it passes through the film formation unit 40, the nitriding treatment unit 50, and the surface treatment unit 70, thereby allowing the surface treatment unit 70 to irradiate the compound film on the workpiece 10 that has been treated by the nitriding treatment unit 50 with ions. Alternatively, if the transport unit 30 arranges the film formation unit 40, the surface treatment unit 70, and the nitriding treatment unit 50 in that order in the transport direction of each unit 40, 50, and 70, the transport unit 30 circulates the workpiece 10 so that it passes through the film formation unit 40, the surface treatment unit 70, and the nitriding treatment unit 50, thereby allowing the surface treatment unit 70 to irradiate the film on the workpiece 10 formed by the film formation unit 40 with ions.

[0076] As shown in Figure 1, the surface treatment section 70 is located in a section other than the section where the film deposition section 40 and the nitriding treatment section 50 are located. As shown in Figure 3, this surface treatment section 70 includes a plasma generator P3 which consists of a cylindrical electrode 71, a shield 72, a process gas introduction section 75, and an RF power supply 76.

[0077] As shown in Figures 1 and 3, the surface treatment section 70 includes a box-shaped cylindrical electrode 71 provided from the top to the inside of the chamber 20. The shape of the cylindrical electrode 71 is not particularly limited, but in this embodiment, it is substantially fan-shaped in plan view. The cylindrical electrode 71 has an opening 71a at its bottom. The outer edge of the opening 71a, i.e., the lower end of the cylindrical electrode 71, faces the upper surface of the workpiece 10 on the rotary table 31 with a small gap between them. The lower end of the cylindrical electrode 71 is the end of the cylindrical electrode 71 where the opening 71a is formed.

[0078] The cylindrical electrode 71 is rectangular in shape, with an opening 71a at one end and a closed end at the other. The cylindrical electrode 71 is attached via an insulating member 71c to an opening 21a provided on the top surface 20a of the chamber 20, such that the end with the opening 71a faces the rotary table 31. The side walls of the cylindrical electrode 71 extend into the interior of the chamber 20.

[0079] The cylindrical electrode 71 is provided with a flange 71b that protrudes outward at the end opposite the opening 71a. An insulating member 71c is fixed between the flange 71b and the periphery of the opening 21a of the chamber 20, thereby maintaining airtightness inside the chamber 20. The insulating member 71c only needs to have insulating properties and is not limited to a specific material, but can be made of a material such as PTFE (polytetrafluoroethylene).

[0080] The opening 71a of the cylindrical electrode 71 is positioned opposite the transport path L of the rotary table 31. The rotary table 31, acting as a transport unit 30, transports the tray 11 on which the workpiece 10 is mounted, passing it through a position opposite the opening 71a. The opening 71a of the cylindrical electrode 71 is sized to accommodate the workpiece 10 mounted on the tray 11 when viewed from above.

[0081] As described above, the cylindrical electrode 71 penetrates the opening 21a of the chamber 20, and a portion of it is exposed to the outside of the chamber 20. The portion of the cylindrical electrode 71 that is exposed to the outside of the chamber 20 is covered by the housing 71d, as shown in Figure 3. The housing 71d keeps the space inside the chamber 20 airtight. The portion of the cylindrical electrode 71 located inside the chamber 20, that is, the area around the side wall of the cylindrical electrode 71, is covered by the shield 72.

[0082] The shield 72 is a fan-shaped rectangular tube coaxial with the cylindrical electrode 71 and is larger than the cylindrical electrode 71. The shield 72 is connected to the chamber 20. Specifically, the shield 72 is erected from the edge of the opening 21a of the chamber 20, and the end extending into the chamber 20 is at the same height as the opening 71a of the cylindrical electrode 71. Since the shield 72 acts as a cathode, just like the chamber 20, it is preferable to construct it from a conductive metal material with low electrical resistance. The shield 72 may be molded integrally with the chamber 20, or it may be attached to the chamber 20 using fixing brackets or the like.

[0083] The shield 72 is provided to stably generate plasma within the cylindrical electrode 71. Each side wall of the shield 72 is provided to extend substantially parallel to each side wall of the cylindrical electrode 71 with a predetermined gap between them. If the gap is too large, the capacitance will decrease, or the plasma generated within the cylindrical electrode 71 may enter the gap, so it is desirable to keep the gap as small as possible. However, if the gap is too small, the capacitance between the cylindrical electrode 71 and the shield 72 will increase, which is also undesirable. The size of the gap should be set appropriately according to the capacitance required for plasma generation. Although Figure 3 only shows the two radially extending side walls of the shield 72 and the cylindrical electrode 71, a gap of the same size as the radial side walls is also provided between the two circumferentially extending side walls of the shield 72 and the cylindrical electrode 71.

[0084] Furthermore, a process gas introduction section 75 is connected to the cylindrical electrode 71. The process gas introduction section 75 includes piping, a gas supply source for process gas G3 (not shown), a pump, valves, etc. Process gas G3 is introduced into the cylindrical electrode 71 through this process gas introduction section 75. The process gas G3 can be changed as appropriate depending on the purpose of the processing. For example, the process gas G3 may be an inert gas such as argon gas, oxygen gas or nitrogen gas, or argon gas in addition to oxygen gas or nitrogen gas.

[0085] An RF power supply 76 for applying a high-frequency voltage is connected to the cylindrical electrode 71. A matching box 77, which is a matching circuit, is connected in series to the output side of the RF power supply 76. The RF power supply 76 is also connected to the chamber 20. When voltage is applied from the RF power supply 76, the cylindrical electrode 71 acts as the anode, and the chamber 20, shield 72, rotary table 31, and tray 11 act as cathodes. In other words, they function as electrodes for reverse sputtering. For this reason, as described above, the rotary table 31 and tray 11 are conductive and are in contact to be electrically connected.

[0086] The matching box 77 stabilizes the plasma discharge by matching the impedances of the input and output sides. The chamber 20 and rotary table 31 are grounded. The shield 72 connected to the chamber 20 is also grounded. Both the RF power supply 76 and the process gas introduction section 75 are connected to the cylindrical electrode 71 via through holes provided in the housing 71d.

[0087] When argon gas, which is the process gas G3, is introduced into the cylindrical electrode 71 from the process gas introduction section 75, and a high-frequency voltage is applied to the cylindrical electrode 71 from the RF power supply 76, a capacitively coupled plasma is generated, the argon gas is converted into plasma, and electrons, ions, and radicals are generated. The ions in this generated plasma are irradiated onto the film being formed on the workpiece 10.

[0088] In other words, the surface treatment unit 70 has a cylindrical electrode 71 with an opening 71a at one end into which process gas G3 is introduced, and an RF power supply 76 that applies a high-frequency voltage to the cylindrical electrode 71. The transport unit 30 transports the workpiece 10 and passes it directly below the opening 71a, thereby drawing ions into the film formed on the workpiece 10 and performing ion irradiation. In the surface treatment unit 70, a negative bias voltage is applied to the tray 11 on which the workpiece 10 is placed and the rotary table 31 in order to draw ions into the film formed on the workpiece 10.

[0089] By using the cylindrical electrode 71 provided in the surface treatment unit 70, it is possible to apply a desired negative bias voltage to the tray 11 and the rotary table 31 on which the workpiece 10 is placed, without applying a high-frequency voltage to the tray 11 or the rotary table 31. These components remain at ground potential, thereby attracting ions into the deposited thin film. This eliminates the need to add a structure for applying a high-frequency voltage to the tray 11 or the rotary table 31, or to consider the area ratio of the anode electrode to the area of ​​other components surrounding the cathode electrode in order to obtain the desired bias voltage, thus simplifying the design of the apparatus.

[0090] Therefore, even when repeatedly performing film deposition and ion irradiation while moving the workpiece 10 in order to flatten the film that is being formed on the workpiece 10, ions can be drawn into the film formed on the workpiece 10 with a simple structure.

[0091] The cylindrical electrode 71 partitions the processing space 74 where the surface treatment is performed by the surface treatment unit 70. The cylindrical electrode 71 suppresses the diffusion of the process gas G3 into the chamber 20. In other words, the surface treatment unit 70 has a processing space 74 that is smaller than the chamber 20 and separated from the processing spaces 41 and 59. Since it is only necessary to adjust the pressure in the processing space 74, which is partitioned into a space smaller than the chamber 20, pressure adjustment can be easily performed, and the plasma discharge can be stabilized. Note that the order and number of the film deposition unit 40, nitriding unit 50, and surface treatment unit 70 are not limited to any particular arrangement.

[0092] The surface treatment unit 70 has the function of planarizing the thin film by applying a negative bias voltage to the tray 11 on which the workpiece 10 is placed and the rotary table 31, thereby attracting ions into the film formed on the workpiece 10. The surface treatment unit 70 makes it possible to easily attract ions into the film formed on the workpiece 10 and planarize it by using a cylindrical electrode 71.

[0093] [Transfer Chamber] The transfer chamber 80 is a container for loading and unloading workpieces 10 into and out of the chamber 20 via gate valves GV1 and GV2. As shown in Figure 1, the transfer chamber 80 has an internal space for accommodating workpieces 10 before they are loaded into the chamber 20. The transfer chamber 80 is connected to the chamber 20 via gate valve GV1. Although not shown, the internal space of the transfer chamber 80 is provided with a transport mechanism for loading and unloading trays 11 loaded with workpieces 10 between the chamber 20 and the transfer chamber 80. The transfer chamber 80 is depressurized by an exhaust mechanism such as a vacuum pump (not shown), and while the vacuum in the chamber 20 is maintained by the transport mechanism, trays 11 loaded with unprocessed workpieces 10 are loaded into the chamber 20, and trays 11 loaded with processed workpieces 10 are unloaded from the chamber 20.

[0094] A load lock unit 81 is connected to the transfer chamber 80 via a gate valve GV2. The load lock unit 81 is a device that, while maintaining a vacuum in the transfer chamber 80, loads trays 11 loaded with unprocessed workpieces 10, which have been brought in from outside the film deposition apparatus 1 by a transport means (not shown), into the transfer chamber 80, and unloads trays 11 loaded with processed workpieces 10 from the transfer chamber 80. The load lock unit 81 can switch between a vacuum state, where the pressure is reduced by an exhaust means such as a vacuum pump (not shown), and an open-air state, where the vacuum is broken.

[0095] [Cooling Chamber] The cooling chamber 90 cools the workpiece 10 that has been removed from the chamber 20. The cooling chamber 90 is a container connected to the transfer chamber 80 and has a cooling means for cooling the workpiece 10 mounted on the tray 11 that has been removed from the transfer chamber 80. As the cooling means, for example, a spray unit that blows cooling gas can be applied. As the cooling gas, for example, Ar gas from the sputtering gas G1 supply source can be used. The cooling temperature is preferably a temperature that can be transported in the atmosphere, for example, 30°C. The tray 11 carrying the processed workpiece 10 from the transfer chamber 80 is transported into the cooling chamber 90 by a transport means (not shown).

[0096] [Control device] The control device 100 controls various elements that constitute the film deposition apparatus 1, such as the exhaust unit 23, sputter gas introduction unit 49, process gas introduction unit 58, exhaust devices 63 and 73, power supply unit 46, RF power supply units 54 and 76, motor 32, exhaust device 63, transfer chamber 80, load lock unit 81, and cooling chamber 90. This control device 100 is a processing unit that includes a PLC (Programmable Logic Controller) and a CPU (Central Processing Unit), and stores a program that describes the control content.

[0097] Specifically, the controlled parameters include the initial exhaust pressure of the film deposition apparatus 1, the power applied to the target 42, antenna 53, and cylindrical electrode 71, the flow rates of sputtering gas G1, process gases G2 and G3, introduction time, exhaust flow rate and exhaust time, film deposition time, surface treatment time, rotation speed of motor 32, cooling temperature, and cooling time. This allows the control device 100 to accommodate a wide variety of film deposition specifications.

[0098] [Operation] Next, the operation of the film deposition apparatus 1 controlled by the control device 100 will be described. Note that the film deposition method performed by the film deposition apparatus 1 as described below is also one embodiment of the present invention. Figure 7 is a flowchart of the film deposition process by the film deposition apparatus 1 of this embodiment. This film deposition process involves alternately stacking AlN films and GaN films on a workpiece 10, and then forming a GaN layer. Since silicon wafers and sapphire substrates have different crystal lattices from GaN, if a GaN film is formed directly, there is a problem that the crystallinity of GaN decreases. To resolve this crystal lattice mismatch, a buffer layer is formed by alternately stacking AlN films and GaN films, and a GaN layer is formed on this buffer layer. This can be used, for example, when forming a GaN layer on a silicon wafer via a buffer layer in the manufacturing of horizontal MOSFETs and LEDs.

[0099] First, the chamber 20 is depressurized to a predetermined pressure by exhausting gases from the exhaust port 21 via the exhaust unit 23. Simultaneously with the exhaust, the heating unit begins heating, and the rotary table 31 is heated (step S01). As the rotary table 31 begins to rotate, the entire chamber 20 is heated by radiation from the heated rotary table 31. Heating along with exhaust promotes the desorption of residual gases such as water molecules and oxygen molecules from the chamber 20. This makes it less likely for residual gases to be mixed in as impurities during film formation, improving the crystallinity of the film. After detecting that the oxygen concentration in the chamber 20 has fallen below a predetermined value using a gas analyzer such as Q-Mass, the rotation of the rotary table 31 is stopped.

[0100] The tray 11, loaded with the workpiece 10, is transported by the transport means into the transport chamber 80 via the load lock section 81 and gate valve GV2, and then sequentially transported into the chamber 20 via gate valve GV1 (step S02). In step S02, the rotary table 31 sequentially moves the empty holding areas HA to the loading locations from the transport chamber 80. Each holding area HA individually holds the tray 11 that has been transported by the transport means. In this way, the trays 11 loaded with the workpiece 10 are placed in all the holding areas HA on the rotary table 31.

[0101] As the rotary table 31 starts rotating again, the workpiece 10 is heated by the heating unit, and the oxide film on the surface of the workpiece 10 is removed by the surface treatment unit 70 (step S03). In other words, the workpiece 10 repeatedly passes under the surface treatment unit 70 as the rotary table 31 rotates. In the surface treatment unit 70, process gas G3 is introduced into the cylindrical electrode 71 from the process gas introduction unit 75, and a high-frequency voltage is applied to the cylindrical electrode 71 from the RF power supply 76. The process gas G3 is turned into plasma by the application of the high-frequency voltage, and the ions in the plasma collide with the surface of the workpiece 10 as it passes under the opening 71a, thereby removing the oxide film.

[0102] Then, a buffer layer is formed by repeatedly and alternately performing the deposition of an AlN film by the film deposition unit 40B and the nitriding treatment unit 50, and the deposition of a GaN film by the film deposition unit 40A and the nitriding treatment unit 50.

[0103] First, particles containing Al atoms are deposited on the workpiece 10 in the film deposition section 40B (step S04). That is, in the film deposition section 40B, the sputtering gas introduction section 49 supplies sputtering gas G1 through the gas inlet 47. The sputtering gas G1 is supplied around the target 42, which is made of Al. The power supply section 46 applies a voltage to the target 42. This causes the sputtering gas G1 to become plasma. Ions generated by the plasma collide with the target 42, knocking out the sputtered particles containing Al atoms.

[0104] After the oxide film on the surface of the workpiece 10 is removed by the surface treatment unit 70, a thin film is formed on the workpiece 10 as it passes through the film deposition unit 40B, with sputtered particles containing Al atoms deposited on the surface. In this embodiment, each time the workpiece passes through the film deposition unit 40B, a thin film thickness of one to two Al atoms is deposited.

[0105] As the workpiece 10 passes through the film deposition section 40B due to the rotation of the rotary table 31, it passes through the nitriding section 50, where the Al atoms of the thin film are nitrided (step S05). That is, in the nitriding section 50, the process gas introduction section 58 supplies process gas G2 containing nitrogen gas through the gas inlet 56 to the processing space 59 sandwiched between the window member 52 and the rotary table 31, and a nitrogen atmosphere is formed in the processing space 59. At this time, since the inner wall section 511 has a pressure increasing plate 511b, the process gas G2 tends to remain in the processing space 59, and the pressure can be raised to a predetermined level (for example, 5 Pa) with a small supply amount. In addition, because the process gas G2 remains in the processing space 59, the amount of process gas G2 flowing out of the processing space 59 is reduced.

[0106] Simultaneously with the introduction of process gas G2, the exhaust device 63 begins to evacuate the exhaust space 60. Process gas G2 that leaks from the processing space 59 through the holes 511c in the pressure increasing plate 511b and the gap between the lower surface of the pressure increasing plate 511b and the rotary table 31 is drawn into the exhaust space 60 by the exhaust device 63 and exhausted from the exhaust port 62. As a result, in addition to the leak prevention effect of the pressure increasing plate 511b, the leak prevention effect of the exhaust device 63 is also achieved, so that process gas G2 does not flow out into the chamber 20 and mix with the film formation section 40 and the surface treatment section 70.

[0107] The RF power supply 54 applies a high-frequency voltage to the antenna 53. The electric field generated by the antenna 53, through which a high-frequency current flows due to the application of the high-frequency voltage, extends to the processing space 59 via the window member 52. This electric field then excites the process gas G2 containing nitrogen gas supplied to this space, generating plasma. The nitrogen species generated by the plasma collide with the thin film of Al on the workpiece 10, bonding with Al atoms to form a nitrided AlN film.

[0108] As the rotary table 31 rotates, the workpiece 10, having passed through the nitriding treatment section 50 and having an AlN film deposited on it, moves toward the surface treatment section 70, where the AlN film is irradiated with ions (step S06). Specifically, in the surface treatment section 70, the process gas introduction section 75 supplies process gas G3 containing argon gas through piping to the processing space 74 inside the cylindrical electrode 71, which is surrounded by the cylindrical electrode 71 and the rotary table 31. When a voltage is applied to the cylindrical electrode 71 by the RF power supply 76, the cylindrical electrode 71 acts as an anode, and the chamber 20, shield 72, rotary table 31, and tray 11 act as cathodes, exciting the process gas G3 supplied to the space inside the cylindrical electrode 71 and generating plasma. Furthermore, the argon ions generated by the plasma collide with the AlN film deposited on the workpiece 10, moving particles to the sparse areas of the film and flattening the film surface.

[0109] Thus, in steps S04 to S06, the workpiece 10 passes through the processing space 41 of the operational film deposition unit 40B to perform film deposition, and the workpiece 10 passes through the processing space 59 of the operational nitriding unit 50 to perform nitriding. Then, the AlN film formed on the workpiece 10 is planarized as the workpiece 10 passes through the space inside the cylindrical electrode 71 of the operational surface treatment unit 70. Note that "operating" is synonymous with the plasma generation operation that generates plasma in the processing spaces of each unit 40, 50, and 70.

[0110] The rotary table 31 continues to rotate until an AlN film of a predetermined thickness is deposited on the workpiece 10, that is, until a predetermined time obtained in advance through simulation or experiment has elapsed (step S07 No). In other words, the workpiece 10 continues to circulate between the film deposition section 40 and the nitriding section 50 until an AlN film of a predetermined thickness is deposited. Since it is preferable to perform nitriding each time Al is deposited to an atomic-level thickness, the rotation speed of the rotary table 31 is set to a relatively slow speed of 50 to 60 rpm in order to balance film deposition and nitriding.

[0111] Once a predetermined time has elapsed (Step S07 Yes), the process moves on to GaN film deposition and nitriding. Specifically, first, the voltage application to the target 42 by the power supply unit 46 is stopped, and the operation of the film deposition unit 40B is stopped.

[0112] Next, particles containing Ga atoms are deposited on the workpiece 10 in the film deposition section 40A (step S08). Then, the Al atoms of the thin film are nitrided as the workpiece 10 with the deposited Ga atoms passes through the nitriding section 50 (step S09). After that, the GaN film is planarized (step S10). Specifically, in the film deposition section 40A, the sputtering gas G1 is turned into plasma by supplying sputtering gas G1 around the target 42, which is composed of Ga and GaN, from the sputtering gas introduction section 49, and by applying a voltage to the target 42 from the power supply section 46. Ions generated by the plasma collide with the target 42 and knock out the sputtered particles containing Ga atoms.

[0113] This results in the formation of a thin film on the surface of the AlN film in which sputtered particles containing Ga atoms are deposited. In this embodiment, each time the film passes through the deposition section 40A, a thin film thickness of one to two Ga atoms is deposited.

[0114] As the rotary table 31 rotates, the workpiece 10 that has passed through the film deposition section 40A passes through the nitriding section 50, where the Ga atoms of the thin film are nitrided. Specifically, in the nitriding section 50, the process gas introduction section 58 supplies process gas G2 containing nitrogen gas through the gas inlet 56 to the processing space 59 sandwiched between the window member 52 and the rotary table 31, forming a nitrogen atmosphere in the processing space 59. The pressure increasing plate 511b allows the pressure to be raised to a predetermined level (for example, 5 Pa) with a small supply amount. Furthermore, since the process gas G2 remains in the processing space 59, the amount of process gas G2 flowing out of the processing space 59 is reduced.

[0115] Simultaneously with the introduction of process gas G2, the exhaust device 63 begins to evacuate the exhaust space 60. Process gas G2 that leaks from the processing space 59 through the holes 511c in the pressure increasing plate 511b and the gap between the lower surface of the pressure increasing plate 511b and the rotary table 31 is drawn into the exhaust space 60 by the exhaust device 63 and discharged from the exhaust port 62. This prevents process gas G2 from flowing out into the chamber 20 and into the film formation section 40 and the surface treatment section 70.

[0116] The electric field generated by the antenna 53, through which a high-frequency current flows when a high-frequency voltage is applied, is generated in the processing space 59 via the window member 52. This electric field then excites the process gas G2 containing nitrogen gas supplied to this space, generating plasma. The nitrogen species generated by the plasma collide with the nitrogen-deficient GaN (non-nitrided) thin film that has been sputter-deposited on the workpiece 10, bonding with Ga atoms and forming a sufficiently nitrided GaN film.

[0117] As the rotary table 31 rotates, the workpiece 10, which has a GaN film formed on it, passes through the nitriding treatment area 50 and moves toward the surface treatment area 70, where the GaN film is irradiated with ions (step S10). The ions collide with the GaN film formed on the workpiece 10, causing particles to move into the sparse areas of the film and flattening the film surface.

[0118] Thus, in steps S08 to S10, the workpiece 10 passes through the processing space 41 of the operating film deposition unit 40A to perform film deposition processing containing Ga, and the workpiece 10 passes through the processing space 59 of the operating nitriding unit 50 to perform nitriding processing and form a GaN film. Then, the workpiece 10 passes through the space inside the cylindrical electrode 71 of the operating surface treatment unit 70 to flatten the GaN film formed on the workpiece 10.

[0119] The rotary table 31 continues to rotate until a predetermined time has elapsed (step S11 No). After the time obtained from simulations and experiments has elapsed, which is the time required for a GaN film of a predetermined thickness to be deposited on the workpiece 10, the process moves back to depositing the Al film in order to stack the Al film and the GaN film. That is, once the predetermined time has elapsed (step S11 Yes), the voltage application to the target 42 by the power supply unit 46 is stopped, and the operation of the film deposition unit 40A is stopped.

[0120] The formation of the AlN film and GaN film as described above is repeated until a predetermined number of layers is reached (Step S12 No). When the predetermined number of layers is reached (Step S12 Yes), the formation of the buffer layer is terminated.

[0121] Furthermore, a GaN layer is formed on top of the buffer layer (step S13). The formation of this GaN layer is carried out in the same manner as the formation of the GaN film in the buffer layer described above. However, the film is formed for a time that results in a predetermined thickness set for the GaN layer.

[0122] After the buffer layer and GaN layer are formed as described above, the tray 11 on which the filmed workpiece 10 is placed is transported by a transport means to the cooling chamber 90 via the transfer chamber 80, and after the workpiece 10 is cooled to a predetermined temperature, it is discharged from the load lock section 81 (step S14).

[0123] In the above explanation, the nitriding treatment unit 50 and the surface treatment unit 70 are kept running continuously during the buffer layer deposition (steps S04 to S13). However, the operation of the nitriding treatment unit 50 and the surface treatment unit 70 may be stopped after each step S04 to S13 is completed. In this case, the operation of the nitriding treatment unit 50 is stopped after the operation of the film deposition unit 40B and the film deposition unit 40A is stopped. This allows sufficient nitriding to be performed on the film surface deposited on the workpiece 10, and an AlN film or GaN film without nitrogen defects can be obtained.

[0124] [Effects] (1) As described above, the film deposition apparatus 1 of this embodiment includes a chamber 20 capable of creating a vacuum inside, a rotary table 31 provided inside the chamber 20 that rotates to circulate and transport the workpiece 10 along a circumferential transport path L, a film deposition section 40 that plasmaizes sputtering gas G1 and deposits film deposition material onto the workpiece 10 circulating and transported by the rotary table 31, and a process gas G2 containing nitrogen gas that plasmaizes and deposits the material onto the workpiece 10 circulating and transported by the rotary table 31. The apparatus comprises a nitriding treatment unit 50 for nitriding particles of the film-forming material, an inner wall portion 511 provided in the nitriding treatment unit 50 that defines a processing space 59 in which process gas G2 is introduced and plasma processing is performed, and has an opening 511a that faces the rotary table 31 without contact, and a pressure increasing plate 511b provided at the end of the inner wall portion 511 in which the opening 511a is formed, extending from the inner wall portion 511 toward the processing space 59, wherein the pressure increasing plate 511b is connected to the inner wall portion 511 and extends around the entire circumference of the inner wall portion 511.

[0125] Process gas G2 leaking from the processing unit PU into the chamber 20 diffuses further away from the processing unit PU. Therefore, even if one attempts to exhaust the gas into the space within the chamber 20 other than the processing unit PU, efficient exhaust is difficult. The space within the chamber 20 other than the processing unit PU has a shape that makes smooth exhaust difficult, or it covers a wide area. Therefore, it is necessary to increase the number of exhaust points or expand the exhaust area, making efficient exhaust difficult.

[0126] Therefore, in the film deposition apparatus 1 of this embodiment, a pressure increasing plate 511b is provided at the end where the opening 511a of the inner wall portion 511 is formed. By providing the pressure increasing plate 511b in this way, the process gas G2 introduced into the processing space 59 in the nitriding processing unit 50 is more likely to remain in the processing space 59. As a result, the pressure in the processing space 59 can be raised to a predetermined pressure with a small supply amount of process gas G2, thereby reducing costs and improving productivity.

[0127] Furthermore, by retaining the process gas G2 in the processing space 59 using the pressure increasing plate 511b, the amount of process gas G2 flowing out of the processing space 59 can be reduced. As a result, the inflow of process gas G2 into the film deposition section 40 can be suppressed, preventing the surface of the target 42 from being nitrided and becoming an insulator, which would hinder the generation of plasma by discharge.

[0128] (2) The pressure increasing plate 511b is ring-shaped with a hole 511c in the center, and the area of ​​the hole 511c is 45% to 95% of the area of ​​the opening 511a of the inner wall portion 511. This makes it possible to efficiently suppress the outflow of process gas G2 leaking from the nitriding treatment portion 50 compared to when the pressure increasing plate 511b is not provided.

[0129] (3) The pressure increasing plate 511b is ring-shaped with a hole 511c in the center, and the area of ​​the hole 511c is 50% to 95% of the area of ​​the opening 511a of the inner wall portion 511. This suppresses the outflow of process gas G2 leaking from the nitriding treatment portion 50 and improves the supply efficiency for supplying process gas G2 to bring the processing space 59 to a predetermined pressure.

[0130] (4) The extension length of the pressure-increasing plate 511b is uniform around the entire circumference. By making the extension length of the pressure-increasing plate 511b uniform around the entire circumference, the paths from the inside to the outside of the nitriding treatment unit 50 become equal. As a result, no path is formed that is likely to flow out to the outside of the nitriding treatment unit 50, and the process gas G2 is more likely to remain in the treatment space 59. In addition, the pressure inside the treatment space 59 becomes uniform, and the processing rate of the film treatment also becomes uniform.

[0131] (5) The outer wall portion 61 covers the periphery of the inner wall portion 511 with a gap in between and has an opening 61a that faces the rotary table 31 without contact, forming an exhaust space 60 on the opposite side of the opening 61a, and further comprises an exhaust port 62 that communicates with the exhaust space 60 and is connected to an exhaust device 63 that sucks in process gas G2 leaking from the gap between the lower surface of the pressure increasing plate 511b and the rotary table 31 and exhausts it to the outside of the chamber 20.

[0132] This allows process gas G2 leaking from the gap between the lower surface of the pressure increasing plate 511b and the rotary table 31 to be discharged to the outside of the chamber 20 by the exhaust space 60. Therefore, it is possible to suppress the inflow of process gas G2 into other processing areas such as the film deposition section 40. In addition, since the exhaust is performed from the exhaust space 60 on the outer periphery of the processing space 59 rather than directly from the processing space 59, it is easier to maintain the pressure in the processing space 59.

[0133] (6) When the distance from the end of the extended tip surface 511d of the pressure increasing plate 511b on the rotary table 31 side to the surface of the rotary table 31 is defined as distance L1, and the distance from the end of the inner wall portion 511 where the opening 511a is formed to the surface of the rotary table 31 is defined as distance L2, then distance L1 is less than or equal to distance L2. As a result, the gap from the lower end of the extended tip surface 511d of the pressure increasing plate 511b to the rotary table 31 is narrowed. Therefore, process gas G2 leaking from the hole 511c of the pressure increasing plate 511b is less likely to flow from the gap to the outer wall portion 61 side, and mixing with other processing parts can be suppressed.

[0134] [Examples] The present invention will be described in more detail based on the examples. However, the present invention is not limited to the following examples. Film deposition apparatuses according to Examples 1 to 10 and the Comparative Example were fabricated by simulation. The basic configuration of the film deposition apparatuses of Examples 1 to 10 and the Comparative Example is as shown in Figures 1 to 3. The film deposition apparatuses of Examples 1 to 10 and the Comparative Example differ only in the configuration of the nitriding treatment section 50, more specifically, in the presence or absence of the pressure increasing plate 511b, or the size of the holes 511c in the pressure increasing plate 511b, but the manufacturing materials, manufacturing methods, and manufacturing conditions are the same. That is, the film deposition apparatuses of Examples 1 to 10 and the Comparative Example all share the features that the nitriding treatment section 50 is equipped with an inner wall portion 511, and that an exhaust space 60 is provided around the nitriding treatment section 50. Two exhaust devices 63 are arranged in the exhaust space 60.

[0135] In Examples 1 to 10, the inner wall portion 511 is equipped with a pressure-increasing plate 511b, and the pressure-increasing plate 511b is formed with the same extension amount around the entire lower end of the inner wall portion 511. The diameter D1 of the hole 511c of each pressure-increasing plate 511b in each example is as shown in Table 1 below. On the other hand, the comparative example does not have a pressure-increasing plate 511b in the inner wall portion 511. The diameter D2 of the opening 511a of the inner wall portion 511 is the same in Examples 1 to 10 and the comparative example, and is 378 mm. Furthermore, the diameter ratio was calculated from the diameter D2 of the opening 511a of the inner wall portion 511 and the diameter D1 of the hole 511c of each pressure-increasing plate 511b. Furthermore, the area of ​​the opening 511a in the inner wall portion 511 and the area of ​​the holes 511c in each pressure increasing plate 511b were calculated based on diameters D1 and D2, and the opening ratio of each hole 511c (area of ​​hole 511c / area of ​​opening 511a × 100) was calculated. The results of each calculation are shown in Table 1 below.

[0136] For the film deposition apparatus of Examples 1 to 10 and the Comparative Example described above, process gas G2 was supplied to the nitriding section 50, and the amount of process gas G2 supplied and the amount of process gas G2 discharged from the processing space 59 were analyzed by simulation so that the pressure in the processing space 59 was 5 Pa (a predetermined pressure). The calculation methods for the supply amount and discharge amount were the same for Examples 1 to 10 and the Comparative Example.

[0137] The analysis conditions were the same for Examples 1 to 10 and the Comparative Example. The analysis was performed with the pressure around the nitriding treatment unit 50 set to 1 Pa. In addition, the analysis was performed with each of the two exhaust devices 63 located in the exhaust space 60 set to an exhaust volume of 150 L / s, for a total exhaust volume of 300 L / s for both devices. Therefore, the outflow volume is the outflow volume of process gas G2 that was not drawn in by the exhaust space 60.

[0138] Table 1 shows the results of the supply and outflow rates analyzed under the above conditions. Figure 8 shows graphs of the supply and outflow rates for Examples 1 to 10 and the comparative example. Furthermore, Figure 9(A) shows a graph showing the relationship between the opening ratio and the outflow rate per unit area, Figure 9(B) shows an enlarged graph of the horizontal axis of Figure 9(A) for the opening ratio range of 100% to 20%, and Figure 10 shows a graph showing the outflow rate and supply rate per unit area in the opening ratio range of 100% to 20%.

[0139] In the comparative example where the pressure-increasing plate 511b is not provided, the size of the opening 511a in the inner wall portion 511 can be considered as the size of the hole 511c of the pressure-increasing plate 511b, so the "Diameter D1 of the hole in the pressure-increasing plate" in Table 1 is 378 mm.

[0140] As shown in Table 1 and Figure 8, in the comparative example without the pressure-increasing plate 511b, the gas supply amount exceeded 730 sccm to reach the predetermined pressure of 5 Pa, and the outflow amount at this time exceeded 550 sccm. On the other hand, in Examples 1 to 10, the gas supply amount to reach the predetermined pressure of 5 Pa was only about 500 sccm even in Example 1, which had the highest amount, a reduction of more than 230 sccm compared to the comparative example, and the outflow amount was also about 360 sccm, a reduction of nearly 200 sccm compared to the comparative example. Furthermore, as shown in Table 1 and Figure 9, and especially in Figure 9(B), by providing the pressure-increasing plate 511b and narrowing the opening 511a of the inner wall portion 511, the outflow amount per unit area can also be reduced. Based on these results, it was confirmed that by setting the diameter ratio to 0.97 or less and the opening ratio to 95% or less, the pressure can be raised to the predetermined level with a small gas supply amount, and the gas outflow amount can also be reduced.

[0141] On the other hand, as the opening ratio decreases, the amount of process gas G2 outflow per unit area increases. In particular, at an opening ratio of 45% (diameter ratio of 0.67), it becomes about the same as the comparative example with an opening ratio of 100% without the pressure increasing plate 511b, and below an opening ratio of 45%, it exceeds that of an opening ratio of 100%. Therefore, it was confirmed that the amount of gas outflow can be efficiently reduced by setting the opening ratio between 45% and 95%.

[0142] Furthermore, as can be seen in Figure 10, the supply rate per unit area decreases up to an opening ratio of 90%, but gradually increases as the opening ratio decreases from 90%, and when the opening ratio falls below 50% (diameter ratio of 0.70), it exceeds the supply rate per unit area at an opening ratio of 100%. Therefore, it was confirmed that the supply efficiency of process gas G2 is also improved by increasing the opening ratio to 50% or more.

[0143] [Variations]

[0144] (1) In the above embodiment, an exhaust space 60 was provided around the nitriding section 50, but as shown in Figure 11, the film deposition apparatus 1 does not need to have an exhaust space 60. Even with this configuration, the process gas G2 can be retained in the processing space 59, the pressure can be raised to a predetermined level with a small supply amount, and the amount of process gas G2 flowing out of the processing space 59 can be reduced.

[0145] (2) Alternatively, an outflow prevention plate 61c may be provided on the outer wall portion 61. For example, as shown in Figure 12(A), the outflow prevention plate 61c is formed at the lower end of the outer wall portion 61. The outflow prevention plate 61c is a ring-shaped flat plate with holes, and the inner surface of the outflow prevention plate 61c that forms the holes is connected to the outer wall portion 61. The outflow prevention plate 61c extends from the outer surface of the outer wall portion 61 in a direction away from the inner wall portion 511. The outflow prevention plate 61c is formed around the entire circumference of the outer wall portion 61. By providing the outflow prevention plate 61c in this way, it is possible to suppress the outflow of process gas G2 that has leaked from the processing space 59 from the outer wall portion 61 and direct it to the exhaust space 60. Therefore, it is possible to suppress the inflow of process gas G2 into other processing PU such as the film deposition portion 40.

[0146] In particular, it is preferable that the gap between the spill prevention plate 61c and the rotary table 31 be shorter than the gap in the exhaust space 60 (the length between the outer surface of the inner wall portion 511 and the inner surface of the outer wall portion 61). The larger the opening area, the greater the ease of gas flow (conductance). Therefore, by making the gap between the spill prevention plate 61c and the rotary table 31 shorter than the gap in the exhaust space 60, the process gas G2 that has spilled out from the processing space 59 can be efficiently guided into the exhaust space 60.

[0147] Furthermore, as shown in Figure 12(B), the spill prevention plate 61c may extend from the outer wall portion 61 toward the inner wall portion 511. The spill prevention plate 61c extends from the inner surface of the outer wall portion 61 toward the center of the nitriding treatment portion 50. The spill prevention plate 61c is provided below the pressure increasing plate 511b, that is, in the gap between the lower surface of the pressure increasing plate 511b and the rotary table 31. The spill prevention plate 61c has an extended tip surface 61d that extends closer to the center of the processing space 59 than the extended tip surface 511d of the pressure increasing plate 511b. Even with this form of spill prevention plate 61c, it becomes easier to guide the process gas G2 that has spilled out of the processing space 59 into the exhaust space 60, and the inflow of process gas G2 into other treatment portions PU such as the film deposition portion 40 can be effectively suppressed.

[0148] (3) In the above embodiment, the pressure increasing plate 511b extended parallel to the workpiece holding surface of the rotary table 31. However, the embodiment is not limited to this form as long as the distance L1, which is the distance from the lower end of the extended tip surface 511d of the pressure increasing plate 511b to the surface of the rotary table 31, is less than or equal to the distance L2, which is the distance from the end of the inner wall portion 511 where the opening 511a is formed to the surface of the rotary table 31. For example, as shown in Figure 13, the pressure increasing plate 511b may extend from the inner surface slightly above the end of the inner wall portion 511 where the opening 511a is formed, and the extended tip surface 511d of the pressure increasing plate 511b may extend closer to the rotary table 31, so that the distance L1 is shorter than the distance L2.

[0149] (4) Alternatively, as shown in Figure 14(A), an inclined portion 511e extending diagonally toward the processing space 59 may be provided at the end of the inner wall portion 511 where the opening 511a is formed. This inclined portion 511e becomes the pressure increasing plate 511b. In this case, the diameter of the portion of the inner wall portion 511 that extends in a straight line corresponds to the diameter D2 of the opening 511a of the inner wall portion 511 in the embodiment, and the inner diameter at the tip of the inclined portion 511e corresponds to the diameter D1 of the hole 511c of the pressure increasing plate 511b. Even with this configuration, the process gas G2 can be retained in the processing space 59, and the amount of process gas G2 flowing out of the processing space 59 can be reduced.

[0150] Furthermore, as shown in Figure 14(B), an inclined portion 61e extending diagonally may be provided at the lower end of the outer wall portion 61. The inclined portion 61e is inclined toward the direction away from the inner wall portion 511. By providing the inclined portion 511e and the inclined portion 61e, the opening width of the inlet of the exhaust space 60 is widened. As a result, it is easier to guide the process gas G2 that has flowed out from the processing space 59 into the exhaust space 60, and the amount of process gas G2 flowing into other processing parts such as the film formation section 40 can be further reduced.

[0151] (5) In the above embodiment, the exhaust space 60 is provided in the nitriding treatment section 50, but it is sufficient for the exhaust space 60 to be provided in at least one of the multiple treatment sections. That is, the exhaust space 60 may be provided in the film deposition section 40 and / or the surface treatment section 70. Specifically, the exhaust space 60 may not be provided in the nitriding treatment section 50, but may be provided in the film deposition section 40 and / or the surface treatment section 70, or it may be provided in the nitriding treatment section 50 and then the exhaust space 60 may also be provided in the film deposition section 40 and / or the surface treatment section 70. When the exhaust space 60 is provided in the film deposition section 40 or the surface treatment section 70, the exhaust space 60 draws in the process gas G2 and prevents the process gas G2 from flowing into the processing space of the film deposition section 40 or the surface treatment section 70.

[0152] Figure 15 shows a modified example in which an exhaust space 60 is provided in the film deposition section 40 adjacent to the nitriding section 50. Figure 15(A) is a schematic perspective view showing the configuration of the film deposition apparatus 1. Figure 15(B) is an enlarged cross-sectional view of the film deposition section 40A. When an exhaust space 60 is provided in the film deposition section 40 adjacent to the nitriding section 50, the partition 22 is trapezoidal in plan view, as shown in Figure 15(A). In other words, the partition 22 in the film deposition section 40 can be considered as an inner wall 511. Alternatively, the outer wall 61 can be placed around the partition 22 with a gap in between. In this way, an exhaust space 60 can be formed between the partition 22 and the outer wall 61. By exhausting the inside of the exhaust space 60 through the exhaust port 62 using an exhaust device 63, the mixing of process gas G2 into the film deposition section 40 can be further suppressed.

[0153] Furthermore, if an exhaust space 60 is provided in the surface treatment area 70, the cylindrical electrode 71 can be considered as the inner wall portion 511 of the surface treatment area 70, and the outer wall portion 61 can be covered around the cylindrical electrode 71 with a gap so that it does not come into contact with the shield 72. In this case, the shield 72 is positioned between the outer wall portion 61 and the cylindrical electrode 71.

[0154] (6) In the above embodiment, the hole 511c was circular, but the shape of the hole 511c is not limited to a circle. The shape of the hole 511c may be, for example, rectangular.

[0155] (7) In the above embodiment, the film deposition apparatus 1 performed down sputtering, that is, the workpiece 10 passed below the nitriding treatment section 50 and performed nitriding treatment. However, the positional relationship between the workpiece 10 and the nitriding treatment section 50 is not limited to this, and it can also be applied to up sputtering (a configuration in which the workpiece 10 passes above the nitriding treatment section 50) or side stuttering (a configuration in which the workpiece 10 flows in a direction parallel to gravity, and the holes 511c of the pressure increasing plate 511b expand in a direction parallel to gravity). In this case, the inner wall portion 511 and the lower surface or lower end of the pressure increasing plate in the above embodiment can be replaced with the end face facing the rotary table 31 or the end on the rotary table 31 side.

[0156] [Other Embodiments] While embodiments of the present invention have been described herein, these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiments described above can be carried out in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. Embodiments and their variations are included in the scope and essence of the invention, as well as in the claims and their equivalents.

[0157] 1 Film Deposition Apparatus 10 Workpiece 11 Tray 20 Chamber 20a Top Surface 20b Bottom Surface 20c Side Surface 21 Exhaust Port 21a, 21b Opening 22 Partition 23 Exhaust Section 30 Transport Section 31 Rotary Table 32 Motor 33 Rotating Shaft 40, 40A, 40B Film Deposition Section 41 Processing Space 42 Target 43 Backing Plate 44 Electrode 46 Power Supply Section 47 Gas Inlet 48 Piping 49 Sputtering Gas Inlet 50 Nitriding Section 511 Inner Wall Section 511a Opening 511b Pressure Increasing Plate 511c Hole 511d Extending Tip Surface 511e Inclined Section 512 Cover Section 52 Window Member 53 Antenna 54 RF Power Supply 55 Matching Box 56 Gas inlet 57 Piping 58 Process gas inlet 59 Processing space 60 Exhaust space 61 Outer wall 61a Opening 61c Leakage prevention plate 61d Extended tip surface 61e Inclined section 62 Exhaust port 63 Exhaust device 70 Surface treatment section 71 Cylindrical electrode 71a Opening 71b Flange 71c Insulating member 71d Housing 72 Shield 74 Processing space 75 Process gas inlet 76 RF power supply 77 Matching box 80 Transfer chamber 81 Load lock section 90 Cooling chamber 100 Control device

Claims

1. A film deposition apparatus comprising: a chamber capable of creating a vacuum inside; a rotary table provided within the chamber that circulates and transports a workpiece along a circumferential transport path by rotating; a film deposition section that plasmaizes sputtering gas and deposits a film deposition material onto the workpiece being circulated and transported by the rotary table to form a film; a nitriding section that plasmaizes a process gas containing nitrogen gas and nitrides the particles of the film deposition material deposited on the workpiece being circulated and transported by the rotary table; an inner wall section provided in the nitriding section section that defines a processing space into which the process gas is introduced and plasma processing is performed, and has an opening that faces the rotary table without contact; and a pressure increasing plate provided at the end of the inner wall section where the opening is formed, extending from the inner wall section toward the processing space, wherein the pressure increasing plate is connected to the inner wall section and extends around the entire circumference of the inner wall section.

2. The film-forming apparatus according to claim 1, characterized in that the pressure-increasing plate is ring-shaped with a hole in the center, and the area of ​​the hole is 45% or more and 95% or less of the area of ​​the opening in the inner wall portion.

3. The film-forming apparatus according to claim 1, characterized in that the pressure-increasing plate is ring-shaped with a hole in the center, and the area of ​​the hole is 50% or more and 95% or less of the area of ​​the opening in the inner wall portion.

4. The film deposition apparatus according to any one of claims 1 to 3, characterized in that the extension length of the pressure increasing plate is uniform over its entire circumference.

5. The film deposition apparatus according to any one of claims 1 to 3, further comprising: an outer wall portion that covers the periphery of the inner wall portion with a gap between them and having an opening that faces the rotating table without contact, and forming an exhaust space on the opposite side of the opening; and an exhaust port that communicates with the exhaust space and is connected to an exhaust device that sucks in the process gas leaking from the gap between the lower surface of the pressure increasing plate and the rotating table and exhausts it to the outside of the chamber.

6. The film deposition apparatus according to any one of claims 1 to 3, characterized in that, when distance L1 is the distance from the end of the extended tip surface of the pressure increasing plate on the rotary table side to the surface of the rotary table, and distance L2 is the distance from the end of the inner wall portion where the opening is formed to the surface of the rotary table, distance L1 is less than or equal to distance L2.

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