Yttrium-based protective film, method for producing same, and member

Abstract

Provided is an yttrium-based protective film having excellent plasma resistance and appearance.　The yttrium-based protective film provided herein contains an yttrium oxide, has a porosity of less than 0.5 vol% and a Vickers hardness of at least 800 HV. The yttrium-based protective film preferably has a thickness of at least 0.3 μm, a crystallite size of at most 40 nm, a Y2O3 (222) plane orientation of at least 50%, a hydrogen atom number of at most 5.0×1021 / cm3, and a compressive stress of 100-1,700 MPa.

Description

Yttrium-based protective film, method for producing the same, and component

[0001] The present invention relates to an yttrium-based protective film, a method for producing the same, and a component.

[0002] When manufacturing semiconductor devices, for example, the surface of a semiconductor substrate (silicon wafer) is micro-machined by dry etching using plasma of a halogen-based gas in a chamber, and the chamber from which the semiconductor substrate is removed after dry etching is cleaned using plasma of oxygen gas.

[0003] At this time, components exposed to the plasma in the chamber may corrode, and the corroded parts may fall off in the form of particles. The fallen particles may adhere to the semiconductor substrate and become foreign matter that causes defects in the circuit.

[0004] Therefore, conventionally, yttrium oxide (Y ２ O ３ A protective film containing yttrium oxide (yttrium-based protective film) is known. Patent Document 1 discloses a thermal spray coating containing yttrium oxide formed by thermal spraying.

[0005] Japanese Patent Application Laid-Open No. 2018-76546

[0006] The inventors have conducted research and found that conventional yttrium-based protective films sometimes have insufficient plasma resistance (corrosion resistance against plasma).

[0007] Furthermore, there are cases where the appearance of the yttrium-based protective film is poor (for example, the yttrium-based protective film has cracks or wrinkles), and in such cases, depending on the application, the yttrium-based protective film is not suitable for use as is.

[0008] The present invention has been made in view of the above points, and has as its object to provide an yttrium-based protective film that is excellent in plasma resistance and appearance.

[0009] As a result of extensive research, the present inventors have found that the above object can be achieved by employing the following configuration, and have completed the present invention.

[0010] That is, the present invention provides the following [1] to

[22] . [1] An yttrium-based protective film containing yttrium oxide, having a porosity of less than 0.5% by volume and a Vickers hardness of 800 HV or more. [2] The yttrium-based protective film according to the above [1], having a thickness of 0.3 μm or more. [3] The yttrium-based protective film according to the above [1] or [2], having a thickness of 15 μm or less. [4] The yttrium-based protective film according to any one of the above [1] to [3], having a crystallite size of 40 nm or less. [5] The yttrium-based protective film according to any one of the above [1] to [4], having a crystallite size of 6 nm or more. [6] Y ２ O ３ [7] The yttrium-based protective film according to any one of [1] to [5], wherein the orientation degree of the (222) plane is 50% or more. ２１ pieces / cm ３The yttrium-based protective film according to any one of [1] to [6] above, wherein the yttrium-based protective film has a compressive stress of 100 to 1700 MPa. [8] The yttrium-based protective film according to any one of [1] to [7] above, wherein the compressive stress is 100 to 1700 MPa. [9] A member having a substrate and the yttrium-based protective film according to any one of [1] to [8] above, disposed on a film-forming surface, which is the surface of the substrate.

[10] The member according to [9] above, wherein the substrate is made of at least one material selected from the group consisting of carbon, ceramics, and metals, the ceramic being at least one material 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 being at least one material selected from the group consisting of aluminum and aluminum-containing alloys.

[11] The member according to [9] above, wherein the substrate is made of aluminum oxide.

[12] The member according to [9] above, wherein the substrate is made of quartz.

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

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

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

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

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

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

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

[14] above, wherein one or more underlayers are provided between the substrate and the yttrium-based protective film, and the underlayers are made of 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 ３The member according to any one of [9] to

[15] above, containing at least one oxide selected from the group consisting of:

[17] The member according to

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

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

[17] above, wherein the substrate has, as the film-forming surface, a first film-forming surface that defines a 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 surfaces is 60% or less.

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

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

[20] A method for producing the yttrium-based protective film according to any one of [1] to [8] above, comprising irradiating a substrate with ions of at least one element selected from the group consisting of oxygen, argon, neon, krypton, and xenon in a vacuum while evaporating an evaporation source to adhere to the substrate, and using Y as the evaporation source. ２ O ３

[21] A method for producing an yttrium-based protective film according to the above

[20] , wherein the substrate is heated to 300°C or higher before the evaporation source is attached to the substrate. [2 ... 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 method for producing an yttrium-based protective film according to the above

[20] or

[21] , which contains at least one oxide selected from the group consisting of:

[0011] According to the present invention, it is possible to provide an yttrium-based protective film that is excellent in plasma resistance and appearance.

[0012] FIG. 1 is a schematic diagram showing an example of a member. FIG. 2 is a schematic diagram showing half of a ring-shaped substrate. FIG. 3 is a schematic diagram showing a part of a cross section of another ring-shaped substrate. FIG. 4 is a schematic diagram showing a part of a cross section of yet another ring-shaped substrate. FIG. 5 is a schematic diagram showing an apparatus used to manufacture a yttrium-based protective film. FIG. 6 is an XRD pattern of the yttrium-based protective film of Example 1. FIG. 7 is a surface SEM photograph of the yttrium-based protective film of Example 1. FIG. 8 is a cross-sectional SEM photograph of the yttrium-based protective film of Example 1.

[0013] The meanings of terms used in the present invention are as follows: A numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits.

[0014] [Yttrium-Based Protective Film] The yttrium-based protective film of this embodiment contains yttrium oxide, has a porosity of less than 0.5% by volume, and has a Vickers hardness of 800 HV or more.

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

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

[0017] In order to set the Vickers hardness within the above range, it is preferable to produce the protective film by the method (the present production method) described below.

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

[0019] <Porosity> In order to obtain excellent plasma resistance and appearance of the protective film, the porosity of the protective film is less than 0.5 vol%, preferably 0.3 vol% or less, more preferably 0.2 vol% or less, and even more preferably 0.1 vol% or less.

[0020] In order to set the porosity within the above range, it is preferable to produce the protective film by the method (the present production method) described below.

[0021] The porosity of the protective film is determined as follows. First, a focused ion beam (FIB) is used to perform a slope process in the thickness direction at an angle of 52° from the surface of the protective film toward the substrate on a portion of the protective film and the substrate (described later), thereby exposing a cross section. The exposed cross section is observed at a magnification of 20,000 times using a field emission scanning electron microscope (FE-SEM), and cross-sectional images are taken. Cross-sectional images are taken at multiple locations. Specifically, for example, when the protective film and substrate are circular, images are taken at a total of five points: one point at 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 periphery, and the size of the cross-sectional image is 6 μm × 5 μm. When 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 image is analyzed using image analysis software (ImageJ, manufactured by the National Institute of Health) to identify the area of ​​the pore portion in the cross-sectional image. The ratio of the area of ​​the pore portion to the area of ​​the entire cross section of the protective film is calculated, and this is regarded as the porosity (unit: volume %) of the protective film. Note that for pores that are too small to be detected by the image analysis software (pores with a pore diameter of 20 nm or less), their area is regarded as 0.

[0022] <Composition> The protective film is made of yttrium oxide (Y ２ O ３ The protective film contains Y. ２ O ３ The content is preferably 95% by mass or more, more preferably 98% by mass or more, and even more preferably 100% by mass. ２ O ３ It consists only of Y ２ O ３ The content satisfies the above range.

[0023] <Degree of Orientation> When the area of ​​the protective film is increased, the Y of the protective film is increased in order to prevent cracks (including wrinkles; the same applies below) from occurring in the protective film. ２ O ３ The orientation degree of the (222) plane (hereinafter also simply referred to as "orientation degree") is preferably high. Specifically, the orientation degree is preferably 50% or more, more preferably 65% ​​or more, and even more preferably 80% or more. In order to set the orientation degree within the above range, it is preferable to manufacture the protective film by the method (the present manufacturing method) described later. The orientation degree can be determined by measuring the Y ２ O ３ The peak intensity of the (222) plane is the ratio (unit: %) of the peak intensity of the (222) plane to the total peak intensity of each plane being 100.

[0024] The XRD pattern of the protective film was obtained by XRD measurement 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: 45 kV, current: 120 mA) 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) Incident optical system: Multilayer mirror + 1.0 mmφ microslit + 1.0 mmφ collimator Receiving optical system: OPEN

[0025] <Crystallite Size> As mentioned above, for example, particles detached from a member 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 defects can be suppressed. Therefore, the crystallite size of the 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 particularly 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 the protective film is preferably 2 nm or more, more preferably 6 nm or more, and even more preferably 7 nm or more.

[0026] In order to set the crystallite size within the above range, it is preferable to produce the protective film by the method (the present production method) described below.

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

[0028] <Thickness> The thickness of the 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 other hand, the thickness of the protective film is, for example, 300 μm or less, preferably 200 μm or less, more preferably 100 μm or less, even more preferably 50 μm or less, and particularly preferably 30 μm or less. The thickness of the protective film may be 10 μm or less.

[0029] The thickness of the protective film is measured as follows: a cross section of the protective film is observed using a scanning electron microscope (SEM), the thickness of the protective film is measured at any five points, and the average value of the five measured points is regarded as the thickness (unit: μm) of the protective film.

[0030] <Number of Hydrogen Atoms> It is preferable that the number of hydrogen atoms in the protective film is small. This results in better plasma resistance of the protective film. The reason for this is presumed to be as follows: If there is a large amount of hydrogen in the protective film, this hydrogen is more likely to react with fluorine contained in the plasma (or the gas used to generate the plasma), and as a result, the protective film is more likely to be damaged. On the other hand, if there is less hydrogen in the protective film, the reaction with fluorine is relatively reduced, and damage to the protective film is suppressed.

[0031] Specifically, the number of hydrogen atoms in the protective film (the number of hydrogen atoms in the film) is 5.0×10 ２１ pieces / cm ３ Preferably, 4.5 x 10 ２１ pieces / cm ３ More preferably, 3.5 x 10 ２１ pieces / cm ３ More preferably, 3.0 x 10 ２１ pieces / cm ３ Even more preferably, 2.5×10 ２１ pieces / cm ３ The following is particularly preferred: 2.3 x 10 ２１ pieces / cm ３ The following are most preferred:

[0032] The hydrogen in the protective film is likely to be due to the influence of moisture contained in the substrate, which will be described later. In particular, when the substrate is made of ceramic, the number of hydrogen atoms in the protective film to be formed can be reduced by heating the substrate (pre-heating) before forming the protective film. Other methods for reducing the number of hydrogen atoms in the protective film will be described later.

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

[0034] The number of hydrogen atoms in the protective film was measured using a secondary ion mass spectrometer (model IMS-6f, manufactured by Ametec Co., Ltd.) to measure the number of hydrogen atoms in the protective film by the primary ion species Cs ＋ The measurement is performed under the conditions of a primary acceleration voltage of 15.0 kV, a detection area of ​​φ8 μm, and a measurement depth of 500 nm.

[0035] <Compressive Stress> The stress (internal stress, residual stress) of the protective film is preferably compressive stress rather than tensile stress. The compressive stress of the 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.), and the compressive stress (film stress σ) of the protective film is determined from the Stoney equation (below). The Stoney equation is expressed as follows: σ=Yd ２ / 6(1-ν)t×8h / c ２ +4h2 In the above formula, σ is film stress, Y is Young's modulus of the substrate, d is thickness of the substrate, ν is Poisson's ratio of the substrate, t is thickness of the protective film, h is amount of warpage, and c is radius of curvature.

[0037] [Member] Fig. 1 is a schematic diagram showing an example of a member 6. The member 6 has a substrate 5 and an yttrium-based protective film 4. As shown in Fig. 1, underlayers (underlayer 1, underlayer 2, and underlayer 3) may be disposed between the substrate 5 and the yttrium-based protective film 4. However, the number of underlayers is not limited to three.

[0038] The member of this embodiment (hereinafter also referred to as "the member") has the above-described present protective film as the yttrium-based protective film. Since the surface of the member is covered with the present protective film, the member has excellent plasma resistance, similar to the present protective film.

[0039] Each part of this member will be described in detail below.

[0040] <Substrate> The substrate has at least a surface on which the yttrium-based protective film (or the underlayer described below) is formed. Hereinafter, this surface may be referred to as the "film formation surface" for convenience.

[0041] <Material> The material of the substrate is appropriately selected depending on the application of the member, etc. The substrate is made of at least one material selected from the group consisting of carbon (C), ceramics, and metals. Here, the ceramics include, for example, glass (soda-lime glass, etc.), quartz, aluminum oxide (Al ２ O ３ The metal is at least one selected from the group consisting of aluminum nitride (AlN), cordierite, yttrium oxide, silicon carbide (SiC), Si-impregnated silicon carbide, silicon nitride (SiN), sialon, and aluminum oxynitride (AlON). The Si-impregnated silicon carbide is obtained by heating and melting elemental Si and impregnating it into 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 substrate is not particularly limited, and examples thereof include a flat plate, a ring, a dome, a concave or a convex shape, and is appropriately selected depending on the use of the member, etc.

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

[0044] <<Maximum Length of 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 forming surface. Specifically, for example, if the film forming surface is circular in plan view, it is its diameter; if it is ring in plan view, it is its outer diameter; if it is rectangular in plan view, it is the length of the maximum diagonal. On the other hand, the maximum length of the film forming surface is, for example, 2000 mm or less, preferably 1500 mm or less.

[0045] 2 is a schematic diagram showing a half-cutout ring-shaped substrate 5. For example, the substrate 5 shown in FIG. １ is 100 mm, inner diameter D ２ When the outer diameter D is 90 mm and the thickness t is 5 mm, the maximum length is 100 mm. １ The film deposition surface 7 may have a first film deposition surface 7a that defines the area of ​​the first film deposition surface 7a and a second film deposition surface 7b that is different from the first film deposition 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] Fig. 3 is a schematic diagram showing a part of a cross section of another ring-shaped substrate 5. As shown in Fig. 3, the substrate 5 may have a plurality of second film formation surfaces 7b.

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

[0048] As described above, one or more underlayers may be disposed between the substrate and the yttrium-based protective film. The formation of the underlayer relieves the tensile stress of the yttrium-based protective film, generating compressive stress, and increases the adhesion of the yttrium-based protective film to the substrate.

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

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

[0051] The underlayer 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 It is preferable that the material contains at least one oxide selected from the group consisting of:

[0052] When two or more underlayers are disposed between the substrate and the yttrium-based protective film, it is preferable that the oxides of the underlayers be different from each other in adjacent underlayers. Specifically, when the oxides of the underlayers are different from each other in adjacent underlayers, for example, the oxide of the underlayer 1 is "SiO ２ ", and the oxide of the underlayer 2 is "Al ２ O ３ +SiO ２ ", and the oxide of the underlayer 3 is "Al ２ O ３ " is one example.

[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 underlayer is measured in the same manner as the thickness of the yttrium-based protective film.

[0054] <Use of Member> The member is used, for example, as a member such as a top plate inside a semiconductor device manufacturing apparatus (such as a plasma etching apparatus or a plasma CVD apparatus), although the use of the member is not limited to this.

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

[0056] This manufacturing method is a so-called ion-assisted deposition (IAD) method. ２ O ３ ) is evaporated and deposited on the substrate, ２ O ３ A protective yttrium film containing

[0057] According to this manufacturing method, a very dense yttrium-based protective film can be formed, that is, the resulting yttrium-based protective film has a small porosity and a small crystallite size.

[0058] However, the thicker the yttrium-based protective film, the more likely it is to crack. Furthermore, as the area of ​​the deposition surface increases, the area of ​​the yttrium-based protective film formed on the deposition surface also increases. In this case, the yttrium-based protective film is also more likely to crack.

[0059] However, the present manufacturing method allows for the production of a dense and hard yttrium-based protective film. Furthermore, when an underlayer is formed, the tensile stress of the yttrium-based protective film is alleviated. Therefore, the yttrium-based protective film obtained by the present manufacturing method is less susceptible to cracking even when the film is thicker or has a larger area.

[0060] Furthermore, the surface roughness (arithmetic mean roughness Ra) of the substrate surface on which the film is to be formed is preferably within the above-mentioned range, which makes the formed yttrium-based protective film denser and harder, and less susceptible to cracking.

[0061] In addition, when methods such as thermal spraying, aerosol deposition (AD), and ion plating (IP) are used, the resulting yttrium-based protective film is likely to have many remaining pores.

[0062] <Apparatus Configuration> This manufacturing method will be described in more detail with reference to FIG. 5 . FIG. 5 is a schematic diagram showing an apparatus used to manufacture an yttrium-based protective film. The apparatus shown in FIG. 5 includes a chamber 11. The interior of the chamber 11 can be evacuated by driving a vacuum pump (not shown). Inside the chamber 11, crucibles 12 and 13 and an ion gun 14 are disposed, and a holder 17 is disposed above these. The holder 17 is integrated with a support shaft 16 and rotates with the rotation of the support shaft 16. A heater 15 is disposed around the holder 17. The holder 17 holds the substrate 5 described above with its film-forming surface facing downward. The substrate 5 held by the holder 17 rotates with the rotation of the holder 17 while being heated by the heater 15. Furthermore, a quartz-crystal film thickness monitor 18 and a quartz-crystal film thickness monitor 19 are attached to the chamber 11.

[0063] <Formation of Yttrium-Based Protective Film> A case where a yttrium-based protective film (not shown in FIG. 5) is formed on the substrate 5 in the apparatus shown in FIG. 5 will be described. First, an evaporation source Y is placed in one or both of the crucibles 12 and 13. ２ O ３ After the substrate 5 is held by the holder 17, the inside of the chamber 11 is evacuated to a vacuum. Next, the heater 15 is driven while the holder 17 is rotated. This causes the substrate 5 to rotate while being heated. In this state, ion-assisted deposition is performed to form a film on the substrate 5. That is, while ions (ion beam) are irradiated from the ion gun 14, the evaporation source Y filled in one or both of the crucibles 12 and 13 is evacuated. ２ O ３The 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 irradiating it with an electron beam (not shown). In this way, the evaporated evaporation source adheres to the substrate 5 (the film formation surface), forming a yttrium-based protective film.

[0064] <Pressure in the Chamber> Film formation is performed in a vacuum. Specifically, the pressure inside the chamber 11 is 6×10 －２ Pa or less is preferable, and 5 × 10 －２ Pa or less is more preferable, and 3×10 －２ On the other hand, the pressure inside the chamber 11 is preferably 1×10 Pa or less. －６ Pa or more is preferable, and 1×10 －５ Pa or more is preferable, and 1×10 －４ Pa or more is more preferable.

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

[0066] <<Film Formation Rate>> The rates at which the evaporation sources in crucibles 12 and 13 evaporate and a film is formed (film formation rates) are monitored in advance using quartz film thickness monitors 18 and 19, respectively. The film formation rates are adjusted by controlling the conditions of the electron beam irradiated onto the evaporation sources and the conditions of the ion beam from ion gun 14 (current value, current density, etc.). During the formation of the yttrium protective film, the film formation rates (unit: nm / min) of each evaporation source are adjusted to the desired value.

[0067] Evaporation source Y ２ O ３ The deposition rate of the evaporation source Y is preferably 1 nm / min or more, more preferably 1.5 nm / min or more, and even more preferably 2 nm / min or more. ２ O ３The film formation rate is preferably 20 nm / min or less, more preferably 15 nm / min or less, and even more preferably 10 nm / min or less.

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

[0069] The ion beam current density is set to 40 μA / cm because the resulting yttrium-based protective film becomes harder. ２ More than 65 μA / cm is preferable. ２ More preferably, 75 μA / cm ２ More preferably, 77 μA / cm ２ On the other hand, the ion beam current density is preferably 140 μA / cm ２ Preferably, 120 μA / cm or less ２ More preferably, 100 μA / cm or less ２ The following is even more preferred:

[0070] <Formation of Underlayer> Before forming the yttrium-based protective film, it is preferable to form the above-described underlayers (e.g., underlayer 1, underlayer 2, and underlayer 3) on the film-forming surface of the substrate 5. The underlayers are formed by ion-assisted deposition, similar to the formation of the yttrium-based protective film. For example, Al ２ O ３ When forming a base layer made of Al, one or both of the crucibles 12 and 13 may contain Al as an evaporation source. ２ O ３ The evaporation source is evaporated while irradiating ions (ion beam) from the ion gun 14, and is deposited on the film formation surface of the substrate 5. The conditions for forming the underlayer are the same as those for forming the yttrium-based protective film.

[0071] Incidentally, the substrate may contain water of crystallization. For example, aluminum oxide (Al ２ O３ When a substrate made of yttrium-based aluminum oxide (e.g., boehmite gamma alumina) is heated from room temperature, the generation of water of crystallization due to hydrates, which are low-temperature stable phases of aluminum oxide, is observed around 520°C. When moisture resulting from the water of crystallization in the substrate is contained in the formed yttrium-based protective film, the number of hydrogen atoms in the yttrium-based protective film is likely to increase.

[0072] Therefore, evaporation source Y ２ O ３ Before adhering the above to the film-forming surface of the substrate (i.e., before forming the yttrium-based protective film), a base layer is formed on the film-forming surface of the substrate. This covers at least the film-forming surface of the substrate, making it difficult for the crystal water of the substrate to be contained in the formed yttrium-based protective film, which is preferable because it reduces the number of hydrogen atoms in the yttrium-based protective film.

[0073] <Preheating of the substrate> As in the formation of the underlayer, the evaporation source Y is used for the reason that the crystal water of the substrate is less likely to be contained in the yttrium-based protective film. ２ O ３ is attached to the film-forming surface of the substrate (i.e., before forming the yttrium-based protective film), the substrate is preferably heated (preheated) at a high temperature. 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, while 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 pre-heating atmosphere is, for example, the air atmosphere.

[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 working 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 with reference to FIG. 5, an yttrium-based protective film (protective film) was produced under the conditions shown in Table 1 below.

[0078] As the substrate, aluminum oxide (Al ２ O ３ ) and having a film-forming surface with a diameter (maximum length) shown in Table 1 below. This substrate was preheated in an air atmosphere while held in a holder in a chamber. The preheating temperature was the temperature (unit: °C) shown in Table 1 below, and the preheating time was 600 minutes. If the substrate was not preheated, a "-" was entered in the preheating temperature column.

[0079] Next, an underlayer and an yttrium-based protective film (protective film) shown in Table 1 were formed on the deposition surface of the substrate under the manufacturing conditions shown in Table 1. As manufacturing conditions not shown in Table 1, oxygen (O) ions were irradiated from an ion gun, the distance between the ion gun and the substrate was 1100 mm, and the current value of the ion beam was 2000 mA.

[0080] Fig. 6 is an XRD pattern of the yttrium-based protective film of Example 1. As shown in Fig. 6, in the yttrium-based protective film of Example 1, it is found that the (222) plane, which is the closest-packed plane of the cubic crystal structure, is preferentially oriented at around 28°.

[0081] The yttrium protective film of Example 1 was observed at a magnification of 50,000 times using an SEM. Figure 7 is a surface SEM photograph of the yttrium protective film of Example 1. Figure 8 is a cross-sectional SEM photograph of the yttrium protective film of Example 1. As shown in Figures 7 and 8, the yttrium protective film of Example 1 is very dense and has excellent smoothness. It is also clear that the particle size is uniform.

[0082] Examples 2 to 33 In Examples 2 to 33, one or more conditions were changed from Example 1. Otherwise, yttrium-based protective films (protective films) were produced in the same manner as in Example 1. The outline of each example is as follows, for example. Note that in each example, changes from Example 1 may have been made in addition to those described 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 underlayer were changed from that in Example 1. In Examples 7 to 10, no underlayer was formed.

[0084] In Examples 11 to 20, the substrate and / or underlayer was changed from that in Example 1. In Example 13, commercially available soda lime glass was used as the substrate (glass). In Example 15, one side of the substrate made of aluminum single crystal was anodized and then polished to form an Al ２ O ３ This underlayer is referred to as "anodized aluminum" in Table 1 below. In Example 16, one side of the aluminum substrate was anodized using oxalic acid to form an underlayer of Al ２ O ３ This underlayer is referred to as an "anodic oxide layer" in Table 1 below.

[0085] In Examples 21 and 22, the thickness of the protective film was changed from Example 1. In Examples 23 and 24, the area of ​​the film-forming surface was changed from Example 1. In Examples 25 to 29, the pressure inside the chamber was changed from Example 1. The protective film in Example 28 was amorphous (for this reason, a "-" was entered in the "Degree of orientation" column). In Examples 30 and 31, the film-forming rate was changed from Example 1. In Examples 32 and 33, the surface roughness (Ra) of the film-forming surface was changed from Example 1.

[0086] Examples 34 to 36 In Example 34, sapphire was used as the protective film, in Example 35, metallic aluminum was used as the protective film, and in Example 36, quartz was used as the protective film.

[0087] <Examples 37 to 38> In Example 37, the IP method was used instead of the IAD method, and Y ２ O ３In Example 38, a protective film of Y was formed by using the CVD method instead of the IAD method. ２ O ３ A protective film of

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

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

[0090] <Etching Amount> The protective film of each example was subjected to ion etching and / or radical etching to evaluate plasma resistance.

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

[0092] In ion etching, CF ４ Gas (flow rate: 100 sccm) and O ２ Discharge (generation of plasma) was carried out using a gas (flow rate: 100 sccm), and CF ４ In radical etching, CF ions were generated. ４ Gas (flow rate: 100 sccm), Ar gas (flow rate: 50 sccm) and O ２ Discharge (generation of plasma) was carried out using a gas (flow rate: 100 sccm) to generate F radicals in the plasma.

[0093] The 15-minute discharge (plasma generation) was repeated five times, and the exposure test was carried out for a total of 150 minutes. In this way, the unmasked portion of the test surface was etched. Then, a stylus-type surface profilometer (Dectak 150, manufactured by ULVAC, Inc.) was used to measure the step between the masked and unmasked portions of the test surface, thereby determining the amount of etching. The results are shown in Table 1 below. Note that when ion etching or radical etching was not performed, a "-" is entered in Table 1 below.

[0094] The smaller the etching amount (unit: 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, the plasma resistance can be evaluated as excellent.

[0095] <Appearance> The appearance of the formed protective film was visually inspected to check for the presence or absence of cracks (including wrinkles; the same applies below). If cracks of 1.0 mm or more were present, this was recorded as "present", if cracks of less than 1.0 mm were present, this was recorded as "minor", and if no cracks were present, this was recorded as "absent", as shown in Table 1 below. If the rating was "minor" or "absent", the appearance could be evaluated as excellent. In the case of "minor", fine cracks were present on the edge surfaces of the protective film, but no cracks were present in the center of the protective film.

[0096]

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

[0098] Several examples are described below. Example 2: By reducing the ion beam current density, the compressive stress of the protective film decreased. Examples 8 to 10: As the surface roughness of the deposition surface increased, the compressive stress of the protective film decreased. Example 12: By increasing the deposition rate, the effect of ion irradiation decreased, and the compressive stress of the protective film decreased. Example 13: In this example, soda-lime glass was used as the substrate, and by lowering the substrate temperature, the compressive stress of the protective film decreased. Examples 26 to 27: By lowering the chamber pressure during deposition, the mean free path became longer, and the kinetic energy due to collisions between the irradiated ions and particles (evaporation source) increased, thereby increasing the compressive stress of the protective film. Example 28: By increasing the deposition rate, the effect of ion irradiation decreased, and the compressive stress of the protective film decreased. Example 29: By reducing the ion beam current density, the compressive stress of the protective film decreased. Example 30: By lowering the deposition source temperature, crystal growth slowed, and the compressive stress of the protective film decreased. Example 31: By reducing the pressure in the chamber during film formation and further reducing the film formation rate, the effect of ion irradiation was enhanced, and the compressive stress of the protective film increased. Examples 32 to 33: By reducing the pressure in the chamber during film formation, the mean free path was lengthened, and the kinetic energy due to collisions between the irradiated ions and particles (evaporation source) increased, thereby increasing the compressive stress of the protective film. Examples 39 to 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, in which the substrate was preheated. 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.

[0099] 1, 2, 3: Underlayer 4: Yttrium protective film 5: Substrate 6: Member 7: Film formation surface 7a: First film formation surface 7b: Second film formation surface 11: Chamber 12, 13: Crucible 14: Ion gun 15: Heater 16: Support shaft 17: Holder 18, 19: Quartz film thickness monitor

Claims

1. Contains yttrium oxide, The porosity is less than 0.5% by volume; Vickers hardness is 800 HV or more, A yttrium-based protective film having a degree of orientation of the (222) plane of Y 2 O 3 of 50% or more.

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

3. 2. The yttrium-based protective coating according to claim 1, having a thickness of 15 μm or less.

4. 2. The yttrium-based protective film according to claim 1, wherein the crystallite size is 40 nm or less.

5. The yttrium-based protective film according to claim 1, wherein the crystallite size is 6 nm or more.

6. The number of hydrogen atoms is 5.0 x 10 ２１ pieces / cm ３ The yttrium-based protective film according to claim 1, wherein:

7. 2. The yttrium protective film according to claim 1, wherein the compressive stress is 100 to 1700 MPa.

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

9. the substrate is made of at least one material selected from the group consisting of carbon, ceramics, and metals, 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; 9. The member according to claim 8, wherein the metal is at least one selected from the group consisting of aluminum and alloys containing aluminum.

10. The member of claim 8 wherein the substrate is comprised of aluminum oxide.

11. The member of claim 8 wherein the substrate is composed of quartz.

12. The member according to claim 8 , wherein the surface roughness of the film-forming surface is less than 1.0 μm in terms of arithmetic mean roughness Ra.

13. 9. The member according to claim 8, wherein the surface roughness of the film-forming surface is 0.01 [mu]m or more in terms of arithmetic mean roughness Ra.

14. The member according to claim 8 , wherein the maximum length of the film-forming surface is 30 mm or more.

15. one or more underlayers are provided between the substrate and the yttrium-based protective film; The underlayer is made of 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 9. The member according to claim 8, comprising at least one oxide selected from the group consisting of:

16. Two or more underlayers are provided between the substrate and the yttrium-based protective film, 16. The member of claim 15, wherein the oxides are different between adjacent underlayers.

17. the substrate has, as the film formation surface, a first film formation surface that defines a maximum length and a second film formation surface that is different from the first film formation surface; the angle between the first film formation surface and the second film formation surface is 20° to 120°; The member according to claim 8 , wherein the ratio of the area of ​​the second film formation surface to the total area of ​​the film formation surface is 60% or less.

18. 9. The component of claim 8, used inside a plasma etching or plasma CVD apparatus.

19. A method for producing the yttrium-based protective film according to any one of claims 1 to 7, comprising evaporating an evaporation source and depositing it on a substrate while irradiating the substrate with ions of at least one element selected from the group consisting of oxygen, argon, neon, krypton, and xenon in a vacuum; The evaporation source is Y ２ O ３ A method for producing a yttrium-based protective film using the method.

20. Before the evaporation source is applied to the substrate, The method for producing an yttrium-based protective film according to claim 19, wherein the substrate is heated at 300°C or higher.

21. Before the evaporation source is applied to the substrate, forming one or more underlayers on the surface of the substrate; The underlayer is made of 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 method for producing an yttrium-based protective film according to claim 19, wherein the yttrium-based protective film contains at least one oxide selected from the group consisting of: