Yttrium protective film, method for manufacturing the same, and components.

Abstract

To provide a yttrium-based protective film with excellent plasma resistance and appearance. [Solution] A yttrium protective film is provided that contains yttrium oxide, has a porosity of less than 0.5 volume%, a Vickers hardness of 800 HV or higher, a crystallite size of 40 nm or less, and a compressive stress of 100 to 1700 MPa. This yttrium protective film has a thickness of 0.3 μm or more, an orientation of the (222) plane of Y2O3 of 50% or more, and a hydrogen atom count of 5.0 × 10¹⁶ 21 pieces / cm 3 The following is preferable:

Description

[Technical Field]

[0001] This invention relates to a yttrium protective film, a method for producing the same, and a component thereof. [Background technology]

[0002] When manufacturing semiconductor devices, for example, the surface of a semiconductor substrate (silicon wafer) is microfabricated using dry etching with a halogen-based gas plasma inside a chamber, or the chamber from which the semiconductor substrate was removed after dry etching is cleaned using an oxygen gas plasma.

[0003] In this process, components exposed to plasma within the chamber may corrode, and the corroded parts may detach from the components in the form of particles. These detached particles can adhere to the semiconductor substrate and become foreign objects that cause defects in the circuit.

[0004] Therefore, conventionally, protective films containing yttrium oxide (Y2O3) (yttrium protective films) have been known as protective films to protect components exposed to plasma. Patent Document 1 discloses a thermal spray coating containing yttrium oxide, which is formed by thermal spraying. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2018-76546 [Overview of the project] [Problems that the invention aims to solve]

[0006] The inventors of this invention investigated and found that conventional yttrium protective films sometimes have insufficient plasma resistance (corrosion resistance to plasma).

[0007] Furthermore, the yttrium protective film may have defects in its appearance (for example, cracks or wrinkles may appear in the yttrium protective film). In such cases, depending on the application, it may not be suitable to use the yttrium protective film as is.

[0008] This invention has been made in view of the above points, and aims to provide a yttrium protective film that has excellent plasma resistance and appearance. [Means for solving the problem]

[0009] As a result of diligent research, the inventors of this invention discovered that the above objective can be achieved by adopting the following configuration, and thus completed the present invention.

[0010] In other words, the present invention provides the following [1] to

[22] . [1] A yttrium protective film containing yttrium oxide, having a porosity of less than 0.5% by volume and a Vickers hardness of 800 HV or higher. [2] The yttrium protective film described in [1] above, having a thickness of 0.3 μm or more. [3] The yttrium protective film described in [1] or [2] above, having a thickness of 15 μm or less. [4] A yttrium protective film according to any of [1] to [3] above, wherein the crystallite size is 40 nm or less. [5] A yttrium protective film according to any of [1] to [4] above, having a crystallite size of 6 nm or more. [6] A yttrium protective film according to any of [1] to [5] above, wherein the degree of orientation of the (222) plane of Y2O3 is 50% or more. [7] The number of hydrogen atoms is 5.0 × 10 21 pieces / cm 3 The yttrium protective film described in any of the above [1] to [6] is as follows: [8] A yttrium protective film as described in any of [1] to [7] above, having a compressive stress of 100 to 1700 MPa. [9]A member having a base material and a yttrium-based protective film according to any one of [1] to [8] disposed on a film-forming surface which is the surface of the base material.

[10] The member according to [9], wherein the base material is composed of at least one selected from the group consisting of carbon, ceramics, and metals; the ceramics is at least one selected from the group consisting of glass, quartz, aluminum oxide, aluminum nitride, cordierite, yttrium oxide, silicon carbide, Si-impregnated silicon carbide, silicon nitride, sialon, and aluminum oxynitride; and the metal is at least one selected from the group consisting of aluminum and alloys containing aluminum.

[11] The member according to [9], wherein the base material is composed of aluminum oxide.

[12] The member according to [9], wherein the base material is composed of quartz.

[13] The member according to any one of [9] to

[12] , wherein the surface roughness of the film-forming surface is less than 1.0 μm in terms of arithmetic mean roughness Ra.

[14] The member according to any one of [9] to

[13] , wherein the surface roughness of the film-forming surface is 0.01 μm or more in terms of arithmetic mean roughness Ra.

[15] The member according to any one of [9] to

[14] , wherein the maximum length of the film-forming surface is 30 mm or more.

[16] The member according to any one of [9] to

[15] , having one or more underlayers between the base material and the yttrium-based protective film, and the underlayer contains at least one oxide selected from the group consisting of Al2O3, SiO2, Y2O3, MgO, ZrO2, La2O3, Nd2O3, Yb2O3, Eu2O3, and Gd2O3.

[17] The member according to

[16] , having two or more of the underlayers between the base material and the yttrium-based protective film, and the oxides are different from each other between adjacent underlayers.

[18] The member according to any one of [9] to

[17] above, wherein the substrate has a first film-forming surface that defines the maximum length and a second film-forming surface different from the first film-forming surface, the angle between the first film-forming surface and the second film-forming surface is 20° to 120°, and the ratio of the area of ​​the second film-forming surface to the total area of ​​the film-forming surface is 60% or less.

[19] A component described in any of [9] to

[18] above, used inside a plasma etching apparatus or a plasma CVD apparatus.

[20] A method for producing a yttrium protective film according to any of [1] to [8] above, wherein the evaporation source is evaporated and deposited on a substrate while irradiating with ions of at least one element selected from the group consisting of oxygen, argon, neon, krypton, and xenon in a vacuum, and Y2O3 is used as the evaporation source.

[21] A method for producing a yttrium protective film according to

[20] , wherein the substrate is heated to 300°C or higher before the evaporation source is attached to the substrate.

[22] A method for producing a yttrium protective film according to

[20] or

[21] , wherein, before attaching the evaporation source to the substrate, one or more underlayers are formed on the surface of the substrate, and the underlayer contains at least one oxide selected from the group consisting of Al2O3, SiO2, Y2O3, MgO, ZrO2, La2O3, Nd2O3, Yb2O3, Eu2O3, and Gd2O3. [Effects of the Invention]

[0011] According to the present invention, a yttrium-based protective film with excellent plasma resistance and appearance can be provided. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing an example of a component. [Figure 2] This is a schematic diagram showing a ring-shaped substrate with half of it cut out. [Figure 3] This is a schematic diagram showing a portion of the cross-section of another ring-shaped substrate. [Figure 4]This is a schematic diagram showing a portion of the cross-section of yet another ring-shaped substrate. [Figure 5] This is a schematic diagram showing the equipment used in the manufacture of yttrium protective films. [Figure 6] This is the XRD pattern of the yttrium protective film in Example 1. [Figure 7] This is a surface SEM image of the yttrium protective film in Example 1. [Figure 8] This is a cross-sectional SEM image of the yttrium protective film in Example 1. [Modes for carrying out the invention]

[0013] The meanings of the terms used in this invention are as follows: A numerical range represented using "~" means a range that includes the numbers written before and after "~" as the lower and upper limits, respectively.

[0014] [Yttrium protective film] The yttrium protective film of this embodiment contains yttrium oxide, has a porosity of less than 0.5 volume%, and a Vickers hardness of 800 HV or higher.

[0015] Hereinafter, the yttrium protective film will also be simply referred to as the "protective film," and the yttrium protective film (protective film) of this embodiment will also be referred to as "this protective film." This protective film offers excellent plasma resistance and appearance. The protective film will be explained in more detail below.

[0016] <Vickers hardness> Due to its excellent plasma resistance, the Vickers hardness of this protective film is 800 HV or higher, preferably 1000 HV or higher, more preferably 1100 HV or higher, even more preferably 1200 HV or higher, particularly preferably 1250 HV or higher, and most preferably 1300 HV or higher. On the other hand, the Vickers hardness of this protective film is, for example, 1800 HV or less, and preferably 1600 HV or less.

[0017] In order to achieve the Vickers hardness within the above range, it is preferable to manufacture the protective film by the method described later (this manufacturing method).

[0018] The Vickers hardness of the protective film is determined in accordance with JIS Z 2244. More specifically, the Vickers hardness of this protective film is determined using a micro-Vickers hardness tester (HM-220, manufactured by Mitutoyo Corporation) with a diamond indenter at a face-to-face angle of 136° and a test force of 0.049 N, resulting in a Vickers hardness of HV0.005.

[0019] <Porosity> For the reasons that this protective film has excellent plasma resistance and appearance, the porosity of this protective film is less than 0.5 volume%, preferably 0.3 volume% or less, more preferably 0.2 volume% or less, and even more preferably 0.1 volume% or less.

[0020] In order to achieve the above-mentioned porosity, it is preferable to manufacture the protective film using the method described later (this manufacturing method).

[0021] The porosity of the protective film is determined as follows: First, a focused ion beam (FIB) is used to create a slope in the thickness direction at a 52° angle from the surface of the protective film toward the substrate, on a portion of the protective film and the substrate described later, thereby exposing the cross-section. The exposed cross-section is observed at a magnification of 20,000x using a field emission scanning electron microscope (FE-SEM), and an image of the cross-section is captured. Cross-sectional images are taken at multiple locations. Specifically, for example, if the protective film and substrate are circular in shape, images are taken at a total of five points: one point in the center of the surface of the protective film (or the surface of the substrate) and four points located 10 mm away from the outer edge. The size of the cross-sectional image is 6 μm × 5 μm. If the thickness of the protective film is 5 μm or more, cross-sectional images are taken at multiple locations so that the entire cross-section of the protective film can be observed in the thickness direction. Next, the obtained cross-sectional images are analyzed using image analysis software (ImageJ, manufactured by National Institute of Health) to identify the area of ​​pores in the cross-sectional images. The ratio of the area of ​​pores to the total cross-sectional area of ​​the protective film is calculated and considered to be the porosity of the protective film (unit: volume %). Pores that are too fine to be detected by the image analysis software (pores with a diameter of 20 nm or less) are considered to have an area of ​​0.

[0022] <composition> This protective film contains yttrium oxide (Y2O3). The Y2O3 content of this protective film is preferably 95% by mass or more, more preferably 98% by mass or more, and even more preferably 100% by mass. The protective film produced by the method described later (this manufacturing method) consists substantially of Y2O3, and its Y2O3 content satisfies the above range.

[0023] <Orientation degree> When the protective film is made to cover a large area, it is preferable that the degree of orientation of the (222) plane of the Y2O3 in the protective film (hereinafter also simply referred to as "degree of orientation") be high, from the viewpoint of suppressing the occurrence of cracks (including wrinkles; the same applies hereinafter) in the protective film. Specifically, the degree of orientation is preferably 50% or more, more preferably 65% ​​or more, and even more preferably 80% or more. In order to achieve the above-mentioned degree of orientation, it is preferable to manufacture the protective film using the method described later (this manufacturing method). The degree of orientation is the percentage (in %) of the peak intensity of the (222) plane in the XRD pattern of the protective film (see Figure 6), where the sum of the peak intensities of all planes of Y2O3 is set to 100.

[0024] The XRD pattern of the protective film is obtained by performing XRD measurements in micro-area 2D (two-dimensional) mode using an X-ray diffractometer (D8 DISCOVER Plus, manufactured by Bruker) under the following conditions. ·X-ray source: CuKα ray (output: 45kV, current: 120mA) • Scanning range: 2θ = 10° to 80° • Step time: 0.2 s / step • Scan speed: 10° / min Step width: 0.02° • Detector: Multimode detector EIGER (2D mode) • Entrance optical system: Multilayer mirror + 1.0 mmφ microslit + 1.0 mmφ collimator • Light-receiving optical system: OPEN

[0025] <Crystallite size> As mentioned above, for example, particles that detach from a component exposed to plasma can adhere to a semiconductor substrate and become foreign matter that causes defects in the circuit. In this case, the smaller the particle size, the more effectively defects can be suppressed. Therefore, the crystallite size of this protective film is preferably 40 nm or less, more preferably 30 nm or less, even more preferably 20 nm or less, even more preferably 15 nm or less, particularly preferably 11 nm or less, even more preferably 10 nm or less, very preferably 9 nm or less, and most preferably 8 nm or less. On the other hand, the crystallite size of this protective film is preferably 2 nm or larger, more preferably 6 nm or larger, and even more preferably 7 nm or larger.

[0026] In order to achieve the crystallite size within the above range, it is preferable to manufacture the protective film using the method described later (this manufacturing method).

[0027] The crystallite size in the protective film is determined using Scherrer's formula, based on the XRD pattern data obtained by XRD measurement of the mirror-polished protective film.

[0028] <Thickness> The thickness of this protective film is, for example, 0.3 μm or more, preferably 1.0 μm or more, more preferably 1.5 μm or more, even more preferably 5 μm or more, particularly preferably 10 μm or more, and most preferably 15 μm or more. On the one hand, the thickness of this protective film is, for example, 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, and particularly preferably 30 μm or less. The thickness of this protective film may be 10 μm or less.

[0029] The thickness of the protective film is measured as follows. Using a scanning electron microscope (SEM), observe the cross-section of the protective film, measure the thickness of the protective film at five arbitrary points, and regard the average value of the five measured points as the thickness (unit: μm) of this protective film.

[0030] 〈Number of hydrogen atoms〉 It is preferable that the number of hydrogen atoms in this protective film is small. Thereby, the plasma resistance of this protective film is more excellent. The reason is presumed as follows. That is, when there is a lot of hydrogen in the protective film, this hydrogen easily reacts with fluorine contained in the plasma (or the gas used for generating the plasma), and as a result, the protective film is easily damaged. On the other hand, if there is little hydrogen in the protective film, relatively, the reaction with fluorine decreases, and the damage of the protective film is suppressed.

[0031] Specifically, the number of hydrogen atoms (hydrogen atoms in the film) in this protective film is preferably 5.0×10 21 atoms / cm 3 or less, more preferably 4.5×10 21 atoms / cm 3 or less, still more preferably 3.5×10 21 atoms / cm 3 or less, even more preferably 3.0×10 21 atoms / cm 3 or less, even more preferably 2.5×10 21 atoms / cm 3 or less, particularly preferably 2.3×10 21 atoms / cm 3 or less, and most preferably.

[0032] Note that the hydrogen in the protective film is likely to be affected by the moisture contained in the base material described later. In particular, when the substrate material is ceramic, the number of hydrogen atoms in the protective film can be reduced by heating the substrate (preheating) before forming the protective film. Further methods for reducing the number of hydrogen atoms in the protective film will be discussed later.

[0033] On the other hand, the number of hydrogen atoms in this protective film is 0.1 × 10⁻⁶. 21 pieces / cm 3 The above is preferable, 0.5 × 10 21 pieces / cm 3 The above is preferable.

[0034] The number of hydrogen atoms in the protective film was determined using a secondary ion mass spectrometer (model IMS-6f, manufactured by AMETEK) and the primary ion species Cs + The result is obtained under the conditions of a primary acceleration voltage of 15.0kV, a detection area of ​​φ8μm, and a measurement depth of 500nm.

[0035] <Compressive stress> The stress (internal stress, residual stress) in this protective film is preferably compressive stress, rather than tensile stress. The compressive stress of this protective film is preferably 100 MPa or more, more preferably 200 MPa or more, and even more preferably 300 MPa or more. On the other hand, the compressive stress of the protective film is preferably 1700 MPa or less, more preferably 1600 MPa or less, and even more preferably 1500 MPa or less.

[0036] The compressive stress of the protective film is determined as follows: A protective film is formed on a quartz glass substrate, and the surface shape of the formed protective film is measured using a surface shape measuring device (Surfcom NEX 241 SD2-13, manufactured by Tokyo Seimitsu Co., Ltd.). The compressive stress (film stress σ) of the protective film is then determined from Stoney's formula (see below). Stoney's formula can be expressed as follows: σ=Yd 2 / 6(1-ν)t×8h / c 2 +4h2 In the above formula, σ: film stress, Y: Young's modulus of the substrate, d: thickness of the substrate, ν: Poisson's ratio of the substrate, t: thickness of the protective film, h: amount of warpage, and c: radius of curvature.

[0037] [Components] Figure 1 is a schematic diagram showing an example of member 6. The component 6 has a base material 5 and a yttrium protective film 4. As shown in Figure 1, a base layer (base layer 1, base layer 2, and base layer 3) may be placed between the substrate 5 and the yttrium protective film 4. However, the base layer is not limited to three layers.

[0038] The component of this embodiment (hereinafter also referred to as "this component") has the above-described protective film as a yttrium protective film. Because this component's surface is covered with this protective film, it exhibits excellent plasma resistance, similar to this protective film.

[0039] The following provides a detailed explanation of each component of this material.

[0040] <Base material> The substrate has a surface on which at least a yttrium protective film (or the underlayer described later) is formed. This surface may be referred to as the "film-forming surface" for convenience below.

[0041] 《Material》 The material of the base material is selected appropriately according to the intended use of the component. The substrate is composed of at least one material selected from the group consisting of, for example, carbon (C), ceramics, and metals. Here, the ceramic is at least one selected from the group consisting of, for example, glass (such as soda-lime glass), quartz, aluminum oxide (Al2O3), aluminum nitride (AlN), cordierite, yttrium oxide, silicon carbide (SiC), Si-impregnated silicon carbide, silicon nitride (SiN), sialon, and aluminum oxynitride (AlON). Si-impregnated silicon carbide is obtained by heating and melting elemental Si and impregnating it with silicon carbide (SiC). The metal is, for example, at least one selected from the group consisting of aluminum (Al) and alloys containing aluminum (Al).

[0042] "shape" The shape of the base material is not particularly limited and can be, for example, flat, ring-shaped, dome-shaped, concave, or convex, and can be appropriately selected depending on the application of the component.

[0043] Surface roughness of the deposited film For the reasons described later, the surface roughness of the film-forming surface of the substrate is preferably less than 1.0 μm, more preferably 0.6 μm or less, even more preferably 0.3 μm or less, even more preferably 0.1 μm or less, particularly preferably 0.08 μm or less, even more preferably 0.05 μm or less, very preferably 0.01 μm or less, and most preferably 0.005 μm or less, as an arithmetic mean roughness Ra. On the other hand, the surface roughness of the film-forming surface of the substrate is preferably 0.01 μm or more, more preferably 0.05 μm or more, and even more preferably 0.1 μm or more, as an arithmetic mean roughness Ra. The surface roughness (arithmetic mean roughness Ra) of the film-deposited surface is measured in accordance with JIS B 0601:2001.

[0044] 《Maximum length of the film-forming surface》 The maximum length of the film-forming surface of the substrate is preferably 30 mm or more, more preferably 100 mm or more, even more preferably 200 mm or more, even more preferably 300 mm or more, particularly preferably 500 mm or more, very preferably 800 mm or more, and most preferably 1000 mm or more. Note that "maximum length" refers to the maximum length of the film-deposited surface. Specifically, for example, if the film-deposited surface is a circle in plan view, it is its diameter; if it is a ring in plan view, it is its outer diameter; and if it is a square in plan view, it is the length of the longest diagonal. On the other hand, the maximum length of the film-forming surface is, for example, 2000 mm or less, and preferably 1500 mm or less.

[0045] Figure 2 is a schematic diagram showing half of the ring-shaped substrate 5 cut out. For example, if the base material 5 shown in Figure 2 has an outer diameter D1 of 100 mm, an inner diameter D2 of 90 mm, and a thickness t of 5 mm, its maximum length is 100 mm. The substrate 5 has a film-forming surface 7, but as shown in Figure 2, it may also have a first film-forming surface 7a that defines the maximum length (outer diameter D1) and a second film-forming surface 7b that is different from the first film-forming surface 7a. The ratio of the area of ​​the second film deposition surface 7b to the total area of ​​the film deposition surface 7 is, for example, 60% or less.

[0046] Figure 3 is a schematic diagram showing a portion of the cross-section of another ring-shaped substrate 5. As shown in Figure 3, the substrate 5 may have a plurality of second film-forming surfaces 7b.

[0047] Figure 4 is a schematic diagram showing a portion of the cross-section of yet another ring-shaped substrate 5. The angle between the first film-forming surface 7a and the second film-forming surface 7b is, for example, 20° to 120°. In the substrate 5 shown in Figure 4, the angle between the first film-forming surface 7a and the second film-forming surface 7b connected to the first film-forming surface 7a is approximately 30°.

[0048] <Base layer> As described above, one or more underlayers may be placed between the substrate and the yttrium protective film. Forming an underlayer relieves the tensile stress in the yttrium protective film, generating compressive stress, and also increases the adhesion of the yttrium protective film to the substrate.

[0049] The number of layers in the underlayment is not particularly limited to an upper limit, but it is preferably 5 layers or less, more preferably 4 layers or less, even more preferably 3 layers or less, especially preferably 2 layers or less, and most preferably 1 layer.

[0050] The underlying layer is preferably an amorphous film or a microcrystalline film.

[0051] The underlying layer preferably contains at least one oxide selected from the group consisting of Al2O3, SiO2, Y2O3, MgO, ZrO2, La2O3, Nd2O3, Yb2O3, Eu2O3, and Gd2O3.

[0052] When two or more underlayers are placed between the substrate and the yttrium protective film, it is preferable that the oxides of the underlayers are different from those of adjacent underlayers. A specific example of a case where adjacent substrate layers have different oxides is when, for instance, the oxide in substrate layer 1 is "SiO2", the oxide in substrate layer 2 is "Al2O3 + SiO2", and the oxide in substrate layer 3 is "Al2O3".

[0053] The thickness of the underlayer is preferably 0.1 μm or more, more preferably 0.4 μm or more, and even more preferably 0.8 μm or more. On the other hand, the thickness of the underlayer is, for example, 15 μm or less, preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 3 μm or less. The thickness of the underlying layer is measured in the same way as the thickness of the yttrium protective film.

[0054] <Uses of the components> This component is used, for example, as a top plate or other component inside semiconductor device manufacturing equipment (such as plasma etching equipment and plasma CVD equipment). However, the uses of this component are not limited to these.

[0055] [Method for manufacturing yttrium protective film and components] Next, a method for manufacturing the yttrium protective film of this embodiment (hereinafter also referred to as "this manufacturing method") will be described. This manufacturing method is also the method for manufacturing the component described above.

[0056] This manufacturing method is what is known as ion-assisted deposition (IAD). In general terms, a yttrium protective film containing Y2O3 is formed by evaporating an evaporation source (Y2O3) in a vacuum while irradiating it with ions, and then depositing it onto the substrate.

[0057] This manufacturing method allows for the formation of a very dense yttrium protective film. Specifically, the resulting yttrium protective film has low porosity and a small crystallite size.

[0058] By the way, the thicker the yttrium protective film, the more prone it is to cracking. Furthermore, as the surface area of ​​the deposited film increases, the yttrium protective film formed on that surface also increases in area. In this case, the yttrium protective film is also prone to cracking.

[0059] However, this manufacturing method yields a dense and hard yttrium protective film. Furthermore, when forming a sub-layer, the tensile stress of the yttrium protective film is relieved. Therefore, the yttrium protective film obtained by this manufacturing method is less prone to cracking, even when its thickness increases or its surface area is expanded.

[0060] Furthermore, the surface roughness (arithmetic mean roughness Ra) of the film-forming surface of the substrate is preferably within the range described above. As a result, the yttrium protective film that is formed becomes denser and harder, and less prone to cracking.

[0061] Furthermore, methods such as thermal spraying, aerosol deposition (AD), and ion plating (IP) tend to leave a large number of pores in the resulting yttrium protective film.

[0062] <Device configuration> This manufacturing method will be explained in more detail based on Figure 5. Figure 5 is a schematic diagram showing the apparatus used in the manufacture of yttrium protective films. The apparatus shown in Figure 5 has a chamber 11. The inside of the chamber 11 can be evacuated by driving a vacuum pump (not shown). Inside the chamber 11 are crucibles 12 and 13 and an ion gun 14, with a holder 17 positioned above them. The holder 17 is integrated with the support shaft 16 and rotates in conjunction with the rotation of the support shaft 16. A heater 15 is positioned around the holder 17. The holder 17 holds the aforementioned substrate 5 with its film-forming surface facing downwards. The substrate 5 held in the holder 17 is heated by the heater 15 and rotates as the holder 17 rotates. Furthermore, a quartz-type film thickness monitor 18 and a quartz-type film thickness monitor 19 are mounted in the chamber 11.

[0063] <Formation of a yttrium protective film> The case in which a yttrium protective film (not shown in Figure 5) is formed on the substrate 5 using the apparatus shown in Figure 5 will be described below. First, one or both of crucibles 12 and 13 are filled with the evaporation source Y2O3. After the holder 17 holds the substrate 5, the inside of the chamber 11 is evacuated to create a vacuum. Next, the holder 17 is rotated while the heater 15 is driven. This rotates the base material 5 while heating it. In this state, ion-assisted deposition is performed to form a film on the substrate 5. In other words, the evaporation source Y2O3 packed in one or both of the crucibles 12 and 13 is evaporated while irradiating with ions (ion beam) from the ion gun 14. The ions irradiated by the ion gun 14 are preferably ions of at least one element selected from the group consisting of oxygen, argon, neon, krypton, and xenon. The evaporation source is melted and evaporated by irradiation with an electron beam (not shown). In this way, the evaporated evaporation source adheres to the substrate 5 (the film-forming surface), and a yttrium protective film is formed.

[0064] Chamber pressure The film deposition is carried out in a vacuum, specifically the pressure inside chamber 11 is 6 × 10⁻⁶. -2 Preferably Pa or less, 5 × 10 -2 Pa or less is more preferable, 3 × 10 -2 Pa or lower is even more preferable. On the other hand, the pressure inside chamber 11 is 1 × 10⁻⁶. -6 Pa is preferable, 1 × 10 -5 Pa or higher is preferable, 1 × 10 -4 Pa or higher is preferable.

[0065] Temperature of the substrate During film formation, the temperature of the substrate 5 heated by the heater 15 is preferably 200°C or higher, and more preferably 250°C or higher. On the other hand, this temperature is preferably 400°C or lower, and more preferably 350°C or lower.

[0066] 《Film formation speed》 Prior to the film formation rate (film deposition rate) due to evaporation of the evaporation sources in crucibles 12 and 13, the film deposition rate is monitored using crystal film thickness monitors 18 and 19, respectively. The film deposition rate is adjusted by controlling the conditions of the electron beam irradiating the evaporation source and the conditions of the ion beam of the ion gun 14 (current value, current density, etc.). During the deposition of the yttrium protective film, the deposition rate (in nm / min) of each evaporation source is adjusted to the desired value.

[0067] The film deposition rate of the evaporation source Y2O3 is preferably 1 nm / min or higher, more preferably 1.5 nm / min or higher, and even more preferably 2 nm / min or higher. The film deposition rate of the evaporation source Y2O3 is preferably 20 nm / min or less, more preferably 15 nm / min or less, and even more preferably 10 nm / min or less.

[0068] Conditions for ion irradiation The distance between the ion gun 14 and the substrate 5 is preferably 700 mm or more, and more preferably 900 mm or more. On the other hand, this distance is preferably 1500 mm or less, and more preferably 1300 mm or less. The ion beam current value is preferably 1000mA or more, and more preferably 1500mA or more. On the other hand, the ion beam current value is preferably 3000mA or less, and more preferably 2500mA or less.

[0069] The ion beam current density is set at 40 μA / cm² because this results in a harder yttrium protective film. 2 The above is preferable, and 65 μA / cm² 2 The above is more preferable: 75 μA / cm 2 The above is even more preferable, 77 μA / cm 2 The above are particularly preferable. On the other hand, the ion beam current density is 140 μA / cm². 2 The following is preferred: 120 μA / cm 2 The following is more preferable: 100 μA / cm 2 The following is even more preferable.

[0070] <Formation of the underlying layer> It is preferable to form the above-described underlayers (for example, underlayer 1, underlayer 2, and underlayer 3) on the film-forming surface of the substrate 5 before forming the yttrium protective film. The underlayer is formed by ion-assisted deposition, similar to the yttrium protective film. For example, when forming a base layer made of Al2O3, Al2O3 is packed into one or both of the crucibles 12 and 13 as an evaporation source, and the evaporation source is evaporated while irradiating with ions (ion beam) from the ion gun 14, and then attached to the film-forming surface of the substrate 5. The conditions for forming the underlayer are the same as those for forming the yttrium protective film.

[0071] By the way, the base material may contain water of crystallization. For example, when an aluminum oxide (Al2O3) substrate is heated from room temperature, the generation of crystal water, which is caused by the hydrate (e.g., boehmite γ-alumina), a low-temperature stable phase of aluminum oxide, can be observed at around 520°C. When moisture originating from the crystalline water of the substrate is contained in the formed yttrium protective film, the number of hydrogen atoms in the yttrium protective film tends to increase.

[0072] Therefore, before depositing the evaporation source Y2O3 onto the film-forming surface of the substrate (i.e., forming a yttrium protective film), a base layer is formed on the film-forming surface of the substrate. This is preferable because, as a result, at least the film-forming surface of the substrate is covered, making it less likely for the crystalline water of the substrate to be included in the formed yttrium protective film, and consequently, the number of hydrogen atoms in the yttrium protective film decreases.

[0073] <Preheating of the base material> Similar to the formation of the underlayer, it is preferable to heat the substrate at a high temperature (preheat) before attaching the evaporation source Y2O3 to the film-forming surface of the substrate (i.e., before forming the yttrium protective film), because this makes it less likely for the crystalline water of the substrate to be incorporated into the yttrium protective film. The preheating temperature is preferably 300°C or higher, more preferably 400°C or higher, even more preferably 450°C or higher, and particularly preferably 500°C or higher. On the other hand, the preheating temperature is, for example, 800°C or lower, preferably 750°C or lower, and more preferably 700°C or lower.

[0074] The preheating time is preferably 60 minutes or more, more preferably 120 minutes or more, even more preferably 240 minutes or more, and particularly preferably 480 minutes or more. On the other hand, the preheating time is preferably 1200 minutes or less, more preferably 1000 minutes or less, even more preferably 800 minutes or less, and particularly preferably 600°C or less.

[0075] The atmosphere for preheating is, for example, an atmospheric environment. [Examples]

[0076] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples described below. Examples 1 to 27, 30 to 31, and 39 to 42 are examples; examples 28 to 29, 32 to 33, and 37 to 38 are comparative examples; and examples 34 to 36 are reference examples.

[0077] <Example 1> Using the apparatus described in Figure 5, a yttrium protective film (protective film) was manufactured under the conditions shown in Table 1 below.

[0078] As the substrate, a circular substrate (thickness: 10 mm) made of aluminum oxide (Al2O3) with a film-forming surface having a diameter (maximum length) as shown in Table 1 below was used. The substrate was preheated in an atmospheric environment while held in a holder inside the chamber. The preheating temperature was as shown in Table 1 below (unit: °C), and the preheating time was 600 minutes. If the substrate was not preheated, "-" was written in the preheating temperature column.

[0079] Next, under the manufacturing conditions shown in Table 1 below, the underlayer and yttrium protective film (protective film) shown in Table 1 below were formed on the film-forming surface of the substrate. Manufacturing conditions not listed in Table 1 below included irradiation with oxygen (O) ions from an ion gun, a distance of 1100 mm between the ion gun and the substrate, and an ion beam current of 2000 mA.

[0080] Figure 6 shows the XRD pattern of the yttrium protective film in Example 1. As shown in Figure 6, in the yttrium protective film of Example 1, the (222) plane, which is the closest-packed plane of the cubic crystal structure, is preferentially oriented around 28°.

[0081] The yttrium protective film of Example 1 was observed using a scanning electron microscope (SEM) at a magnification of 50,000x. Figure 7 is a surface SEM image of the yttrium protective film in Example 1. Figure 8 is a cross-sectional SEM image of the yttrium protective film in Example 1. As shown in Figures 7 and 8, the yttrium protective film of Example 1 is extremely dense and exhibits excellent smoothness. It can also be seen that the particle size is uniform.

[0082] <Examples 2-33> In Examples 2 through 33, one or more conditions were changed from those in Example 1. Otherwise, the yttrium protective film (protective film) was manufactured in the same manner as in Example 1. In general terms, for example, it is as follows. Note that in each example, there may be changes from Example 1 in addition to the descriptions below.

[0083] In Example 2, the ion beam current density was changed from that in Example 1. In Examples 3 to 6, the number of layers and / or composition of the underlying layers were changed from those in Example 1. In Examples 7-10, no subsoil layer was formed.

[0084] In Examples 11 to 20, the base material and / or underlayer were changed from those in Example 1. In Example 13, commercially available soda-lime glass was used as the base material (glass). In Example 15, one side of a substrate made of aluminum single crystal was anodized and then polished to create an Al2O3 base layer. This base layer is referred to as "anodized" in Table 1 below. In Example 16, one side of an aluminum substrate was anodized using oxalic acid to create a base layer consisting of Al2O3. This base layer is referred to as the "anodic oxide layer" in Table 1 below.

[0085] In Examples 21 and 22, the thickness of the protective film was changed from that in Example 1. In Examples 23 and 24, the area of ​​the film deposition surface was changed from that in Example 1. In Examples 25 to 29, the chamber pressure was changed from that in Example 1. Note that the protective film in Example 28 was amorphous (therefore, "-" is written in the "Orientation Degree" column). In Examples 30 and 31, the film deposition rate was changed from that in Example 1. In Examples 32 and 33, the surface roughness (Ra) of the film-deposited surface was changed from that in Example 1.

[0086] <Examples 34-36> In Example 34, sapphire was used as the protective layer. In Example 35, metallic aluminum was used as the protective film. In Example 36, quartz was used as the protective layer.

[0087] <Examples 37-38> In Example 37, a protective film of Y2O3 was formed using the IP method, not the IAD method. In Example 38, a protective film of Y2O3 was formed using the CVD method, not the IAD method.

[0088] <Examples 39-42> In Examples 39 to 42, the protective film was formed in the same manner as in Examples 7, 1, 3, and 26, respectively, except that the substrate was not preheated.

[0089] <Properties of the protective film> For each example of the protective film, the number of hydrogen atoms, Vickers hardness, porosity, crystallite size, degree of orientation, thickness, and compressive stress were determined based on the method described above. The results are shown in Table 1 below. Note that compressive stress values ​​are indicated as negative numbers.

[0090] <Etching amount> For each example, the protective film was subjected to ion etching and / or radical etching to evaluate its plasma resistance.

[0091] Specifically, first, a 10mm x 5mm surface of the protective film was polished to a mirror finish, and then a portion of the polished surface (referred to as the "test surface") was masked with Kapton tape. Next, using a CCP-type plasma etching apparatus, a plasma was generated by discharging a gas (described later) under conditions of a pressure of 10 Pa and an RF power of 600 W, and the test surface was exposed to the generated plasma (exposure test).

[0092] In ion etching, CF4 gas (flow rate: 100 sccm) and O2 gas (flow rate: 100 sccm) were used to generate a discharge (plasma), and CF4 ions were produced in the plasma. In radical etching, discharge (plasma generation) was performed using CF4 gas (flow rate: 100 sccm), Ar gas (flow rate: 50 sccm), and O2 gas (flow rate: 100 sccm), generating F radicals in the plasma.

[0093] A 15-minute discharge (plasma generation) was repeated five times, resulting in a total exposure test of 150 minutes. This etched the unmasked areas of the test surface. Subsequently, the amount of etching was determined by measuring the step difference between the masked and unmasked areas of the test surface using a stylus-type surface shape measuring instrument (ULVAC, Inc., Decak150). The results are shown in Table 1 below. If ion etching or radical etching was not performed, a "-" is indicated in Table 1 below.

[0094] The smaller the etching amount (in nm), the better the plasma resistance can be evaluated. Specifically, if the etching amount (ion etching amount, radical etching amount) is 200 nm or less, it can be evaluated as having excellent plasma resistance.

[0095] <exterior> The appearance of the formed protective film was visually inspected to check for the presence or absence of cracks (including wrinkles; the same applies hereafter). Table 1 below indicates the presence of cracks of 1.0 mm or larger ("Present"), cracks smaller than 1.0 mm ("Minor"), and no cracks ("Absent"). A rating of "Minor" or "Absent" indicates excellent appearance. In the case of "minor" damage, fine cracks were present on the edges of the protective film, but no cracks were found in the center of the protective film.

[0096] [Table 1] TIFF2026069667000002.tif225145 TIFF2026069667000003.tif225144

[0097] <Summary of Evaluation Results> As shown in Table 1 above, the yttrium protective films of Examples 1-27 and 30-31 were found to have excellent plasma resistance and appearance. In contrast, the yttrium protective films of Examples 28-29, 32-33, and 37-38 were insufficient in at least one of the following: plasma resistance and appearance.

[0098] The following are some examples. Example 2: By reducing the ion beam current density, the compressive stress of the protective film was reduced. Examples 8-10: As the surface roughness of the film-forming surface increased, the compressive stress of the protective film decreased. Example 12: By increasing the film deposition rate, the effect of ion irradiation decreased, and the compressive stress of the protective film was reduced. Example 13: This example uses soda-lime glass as the substrate, and the compressive stress of the protective film decreased by lowering the temperature of the substrate. Examples 26-27: By lowering the chamber pressure during film deposition, the mean free path increased, and the kinetic energy due to collisions between irradiated ions and particles (evaporation sources) increased, resulting in increased compressive stress on the protective film. Example 28: By increasing the film deposition rate, the effect of ion irradiation decreased, and the compressive stress of the protective film was reduced. Example 29: By reducing the ion beam current density, the compressive stress of the protective film was reduced. Example 30: Lowering the temperature of the deposition source slowed down crystal growth, and the compressive stress of the protective film decreased. Example 31: By lowering the chamber pressure during film deposition and further reducing the deposition rate, the effect of ion irradiation increased, and the compressive stress of the protective film increased. Examples 32-33: By lowering the chamber pressure during film deposition, the mean free path increased, and the kinetic energy due to collisions between irradiated ions and particles (evaporation sources) increased, resulting in increased compressive stress on the protective film. Examples 39-42: Since the substrate was not preheated, the number of hydrogen atoms in the protective film increased compared to Examples 7, 1, 3, and 26, where the substrate was preheated. Furthermore, the entire contents of the specifications, claims, drawings, and abstracts of Japanese Patent Application No. 2022-131021, filed on August 19, 2022, and Japanese Patent Application No. 2022-175428, filed on November 1, 2022, are incorporated herein by reference as disclosure of the present invention. [Explanation of Symbols]

[0099] 1, 2, 3: Base layer 4: Yttrium protective film 5: Base material 6: Components 7: Film forming surface 7a: First film forming surface 7b: Second film formation surface 11: Chamber 12, 13: Crucible 14: Ion gun 15: Heater 16: Support shaft 17: Holder 18, 19: Crystal-type film thickness monitor

Claims

1. It contains yttrium oxide, Porosity is less than 0.5 volume%, The Vickers hardness is 800 HV or higher. The crystallite size is 40 nm or less. A yttrium protective film with a compressive stress of 100 to 1700 MPa.

2. The yttrium protective film according to claim 1, having a thickness of 0.3 μm or more.

3. The yttrium protective film according to claim 1, wherein the thickness is 15 μm or less.

4. The yttrium protective film according to claim 1, wherein the crystallite size is 6 nm or larger.

5. Y ２ O ３ The yttrium protective film according to claim 1, wherein the degree of orientation of the (222) surface is 50% or more.

6. The number of hydrogen atoms is 5.0 × 10 ２１ pieces / cm ３ The yttrium protective film according to claim 1, which is as follows:

7. Substrate and A member having a yttrium protective film according to any one of claims 1 to 6, which is disposed on the film-forming surface that is the surface of the substrate.

8. The substrate is composed of at least one selected from the group consisting of carbon, ceramics, and metal. The ceramic is at least one selected from the group consisting of glass, quartz, aluminum oxide, aluminum nitride, cordierite, yttrium oxide, silicon carbide, Si-impregnated silicon carbide, silicon nitride, Sialon, and aluminum oxynitride. The member according to claim 7, wherein the metal is at least one selected from the group consisting of aluminum and aluminum-containing alloys.

9. The member according to claim 7, wherein the base material is composed of aluminum oxide.

10. The member according to claim 7, wherein the base material is composed of quartz.

11. The member according to claim 7, wherein the surface roughness of the film-forming surface is less than 1.0 μm in terms of arithmetic mean roughness Ra.

12. The member according to claim 7, wherein the surface roughness of the film-forming surface is 0.01 μm or more in terms of arithmetic mean roughness Ra.

13. The member according to claim 7, wherein the maximum length of the film-forming surface is 30 mm or more.

14. Between the substrate and the yttrium protective film, there is one or more underlayers, The base layer is Al ２ O ３ , SiO ２ , Y ２ O ３ , MgO, ZrO ２ , La ２ O ３ , Nd ２ O ３ , Yb ２ O ３ , Eu ２ O ３ and Gd ２ O ３ The member according to claim 7, containing at least one oxide selected from the group consisting of

15. Between the substrate and the yttrium protective film, there are two or more of the aforementioned underlayers, The member according to claim 14, wherein the oxides are different from each other in adjacent substrate layers.

16. The substrate has a first film-forming surface that defines the maximum length, and a second film-forming surface that is different from the first film-forming surface, The angle between the first film-forming surface and the second film-forming surface is 20° to 120°. The member according to claim 7, wherein the ratio of the area of ​​the second film-forming surface to the total area of ​​the aforementioned film-forming surface is 60% or less.

17. The component according to claim 7, used inside a plasma etching apparatus or a plasma CVD apparatus.

18. A method for producing a yttrium protective film according to any one of claims 1 to 6, In a vacuum, the evaporation source is evaporated and deposited onto the substrate while irradiating it with ions of at least one element selected from the group consisting of oxygen, argon, neon, krypton, and xenon. As the evaporation source, Y ２ O ３ A method for producing a yttrium protective film using the following method.

19. Before attaching the evaporation source to the substrate, A method for producing a yttrium protective film according to claim 18, wherein the substrate is heated to 300°C or higher.

20. Before attaching the evaporation source to the substrate, One or more underlayers are formed on the surface of the substrate. The aforementioned base layer is Al ２ O ３ SiO ２ , Y ２ O ３ MgO, ZrO ２ La ２ O ３ , Nd ２ O ３ Yb ２ O ３ , Eu ２ O ３ and Gd ２ O ３ A method for producing a yttrium protective film according to claim 18, comprising at least one oxide selected from the group consisting of the following.

Images