Protective film, member, plasma processing device, and method for producing protective film

Abstract

Provided is a protective film having excellent plasma resistance.　The protective film comprises yttrium, aluminum, and oxygen, gives an X-ray diffraction pattern in which there is no YAlO3 (121)-plane peak or a YAlO3 (121)-plane peak has a half-value width of 1° or greater, and gives a Raman spectrum in which the ratio of a maximum scattering intensity in the range of 200 cm-1 to 350 cm-1 to a scattering intensity at 1,000 cm-1 is less than 1.000 or is 2.000 or higher.

Description

Protective film, component, plasma processing apparatus, and method for manufacturing a protective film

[0001] The present invention relates to a protective film, a component, a plasma processing apparatus, and a method for manufacturing a protective film.

[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] During this process, parts of the chamber exposed to the plasma may corrode and detach as particulate matter. These detached particles can adhere to the semiconductor substrate and become foreign objects that cause defects in the circuit.

[0004] Therefore, conventionally, protective films have been used to protect parts exposed to plasma. Patent Document 1 discloses an amorphous protective film containing yttrium (Y), aluminum (Al), and oxygen (O). Patent Document 2 discloses a protective film containing yttrium aluminum garnet (YAG) crystals.

[0005] Japanese Patent Publication No. 2023-533712, Japanese Patent Publication No. 2006-315955

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

[0007] This invention has been made in view of the above points, and aims to provide a protective film with excellent plasma resistance.

[0008] The inventors, after diligent study, found that the above objective can be achieved by adopting the following configuration, and thus completed the present invention. That is, the present invention provides the following [1] to

[14] . [1] A material containing yttrium, aluminum, and oxygen, wherein in the X-ray diffraction pattern, YAlO ３ The (121) plane does not have a peak, or YAlO ３The full width at half maximum of the peak of the (121) plane is 1° or more, and in the Raman spectrum, the maximum scattering intensity in the range of 200 cm －１ or more and 350 cm －１ or less and the ratio of the scattering intensity at 1000 cm －１ is less than 1.000 or 2.000 or more, a protective film. [2] The protective film according to [1] above, wherein the atomic ratio Al / Y of yttrium and aluminum is 0.40 or more and 2.00 or less. [3] The protective film according to [1] or [2] above, wherein the nanoindentation hardness is 9.00 GPa or more. [4] The protective film according to any one of [1] to [3] above, wherein the surface roughness is 50.0 nm or less in terms of the arithmetic mean height Sa. [5] In the above X-ray diffraction pattern, Y ３ Al ５ O １２ the peak of the (420) plane does not exist, or the full width at half maximum of the peak of the (420) plane of Y ３ Al ５ O １２ is 1° or more, the protective film according to any one of [1] to [4] above. [6] A protective film containing yttrium, aluminum and oxygen, and in the X-ray diffraction pattern, the peak of the (121) plane of YAlO ３ does not exist, or the full width at half maximum of the peak of the (121) plane of YAlO ３ is 1° or more, and the nanoindentation hardness is 10.00 GPa or more. [7] The protective film according to [5] above, wherein the atomic ratio Al / Y of yttrium and aluminum is 1.30 or more and 2.00 or less. [8] In the above X-ray diffraction pattern, Y ３ Al ５ O １２ the peak of the (420) plane does not exist, or the full width at half maximum of the peak of the (420) plane of Y ３ Al ５ O １２ is 1° or more, the protective film according to [6] above. [9] A member including a substrate and the protective film according to any one of [1] to [8] above in this order.

[10] A plasma processing apparatus including the member according to [9] above as a component constituting the inner surface.

[11] Containing yttrium, aluminum and oxygen, and in the X-ray diffraction pattern, YAlO３ The (121) plane does not have a peak, or YAlO ３ A method for producing a protective film having a peak width at half maximum of 1° or more on the (121) plane, comprising forming a film precursor containing yttrium, aluminum, and oxygen, and obtaining the protective film by calcining the film precursor.

[12] The method for producing a protective film according to

[11] , wherein the film precursor is calcined at a temperature of 300°C or higher.

[13] The method for producing a protective film according to

[11] or

[12] , wherein the film precursor is calcined for 3 hours or more.

[14] The method for producing a protective film according to any one of

[11] to

[13] , wherein the film precursor is formed by sputtering or vapor deposition.

[0009] According to the present invention, a protective film with excellent plasma resistance can be provided.

[0010] This is a schematic cross-sectional view showing an example of a component.

[0011] The meanings of 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.

[0012] [Protective film] The protective film of the first embodiment contains yttrium, aluminum, and oxygen, and in the X-ray diffraction pattern, YAlO ３ The (121) plane does not have a peak, or YAlO ３ The full width at half maximum of the peak of the (121) plane is 1° or more, and in the Raman spectrum, at 200 cm² －１ More than 350cm －１ The maximum scattering intensity in the following range and 1000 cm －１ The ratio to the scattering intensity at is less than 1.000 or greater than 2.000.

[0013] The protective film of the second embodiment contains yttrium, aluminum, and oxygen, and in the X-ray diffraction pattern, YAlO ３ The (121) plane does not have a peak, or YAlO ３ The (121) plane peak has a full width at half maximum of 1° or more, and the nanoindentation hardness is 10.00 GPa or more.

[0014] The first and second embodiments may be collectively referred to as this embodiment below. The protective film of this embodiment has excellent plasma resistance. The reason for this is not clear, but it is presumed to be as follows.

[0015] First, the protective film of this embodiment is obtained by firing an amorphous film precursor. Here, the Raman spectrum (first embodiment) and nanoindentation hardness (second embodiment) both indicate that the protective film is a fired product and not an unfired product (film precursor). Furthermore, the X-ray diffraction patterns (first and second embodiments) indicate that the protective film is fired without crystallizing the film precursor. Such a protective film is harder than an amorphous film, while its lack of crystallization suppresses embrittlement, resulting in superior plasma resistance.

[0016] The protective film of this embodiment will be described in more detail below.

[0017] <Composition> The protective film contains yttrium (Y), aluminum (Al), and oxygen (O). The total content of Y, Al, and O in the protective film is preferably 85 atomic% or more, more preferably 90 atomic% or more, and even more preferably 95 atomic% or more. The upper limit is not particularly limited and may be 100 atomic%. When the protective film is manufactured by the method described later, it shall satisfy the above composition.

[0018] <Atomic Ratio (Al / Y)> Next, the atomic ratio (Al / Y) of Y to Al in the protective film will be explained. The atomic ratio (Al / Y) of the protective film is the ratio of the number of Al atoms to the number of Y atoms in the protective film. The atomic ratio (Al / Y) of the protective film is, for example, 0.40 or more, and may be 0.45 or more. From the viewpoint of increasing the hardness of the protective film, the atomic ratio (Al / Y) of the protective film is preferably 0.70 or more, more preferably 0.90 or more, even more preferably 1.30 or more, and particularly preferably 1.40 or more. On the other hand, the atomic ratio (Al / Y) of the protective film is, for example, 2.00 or less, and may be 1.80 or less for the reason that the plasma resistance of the protective film is better. For the reason that the plasma resistance of the protective film is better, the atomic ratio (Al / Y) of the protective film is preferably 1.30 or less, more preferably 1.10 or less, even more preferably 0.70 or less, and particularly preferably 0.60 or less.

[0019] The atomic ratio (Al / Y) of the protective film is determined by quantifying each element using an energy-dispersive X-ray analyzer (EDX) attached to a scanning electron microscope (SEM).

[0020] <XRD Pattern> Y ３ Al ５ O １２ A garnet crystal composed of these elements is also called yttrium aluminum garnet (YAG). ４ Al ２ O ９ The monoclinic crystal composed of YAlO is also called yttrium aluminum monoclinic (YAM). ３ The perovskite-type crystal composed of these materials is also called yttrium aluminum perovskite (YAP).

[0021] YAG, YAM, and YAP each exhibit peaks at specific locations (ranges) in the X-ray diffraction (XRD) chart, each attributed to a specific plane. The peak of the (420) plane of YAG appears at 2θ = 28.6–30.1°. The peak of the (112) plane of YAM appears at 2θ = 29.8–31.3°. The peak of the (121) plane of YAP appears at 2θ = 33.2–34.7°.

[0022] For convenience, in the following, the "peak of the (420) plane of YAG" will be referred to as the "YAG (420) peak." This also applies to YAM and YAP.

[0023] Incidentally, although the film precursor contains Y, Al, and O, it is amorphous, so the XRD pattern of the film precursor does not show YAP(121) peaks, etc. On the other hand, when the film precursor is calcined at high temperature and crystallized, the XRD pattern shows the YAP(121) peak. Furthermore, even if YAG and / or YAM are produced by calcination, at least a portion of them become YAP during the crystallization process, and the YAP(121) peak appears.

[0024] However, in this embodiment, the film precursor is fired without crystallization. Therefore, the YAP(121) peak does not appear in the XRD pattern of the protective film obtained by firing. Or, if it does appear, it is very slight (i.e., a broad peak appears). Specifically, the YAP(121) peak is absent in the XRD pattern of the protective film, or the full width at half maximum (FWHM) of the YAP(121) peak is 1° or more at 2θ. In other words, there are no YAP(121) peaks with a FWHM of less than 1°. As a result, the protective film has excellent plasma resistance, as described above.

[0025] For the same reasons as the YAP(121) peak, it is preferable that the XRD pattern of the protective film does not contain a YAG(420) peak, or that the full width at half maximum (FWHM) of the YAG(420) peak is 1° or greater (i.e., there are no YAG(420) peaks with a FWHM of less than 1°). Furthermore, it is preferable that the XRD pattern of the protective film does not contain a YAM(112) peak, or that the FWHM of the YAM(112) peak is 1° or greater (i.e., there are no YAM(112) peaks with a FWHM of less than 1°).

[0026] The XRD pattern of the protective film is obtained by performing a standard measurement using a desktop X-ray diffractometer (MiniFlex, Rigaku Corporation) under the following conditions: • X-ray source: CuKα (output: 45kV, current: 40mA) • Scanning range: 2θ = 10 to 80° • Step time: 0.4° / step • Scan speed: 10° / min • Step width: 0.02° • Incident optical system: 1.0mmφ microslit

[0027] <Raman Spectrum> When the film precursor is calcined, the Raman spectrum changes. Specifically, for example, at 200 cm² －１ More than 350cm －１ Within the following range, the scattering intensity is lower than that of the film precursor at low firing temperatures, but a broad peak appears at higher firing temperatures, and a sharp peak attributed to the crystal appears at even higher firing temperatures. This occurs at 460 cm⁻¹. －１ More than 550cm －１ The following range, and 800 cm －１ More than 1000cm －１ The same behavior is observed in the following range as well. On the other hand, for example, even if the firing temperature is raised to, for example, 1000°C, 1000 cm －１ The scattering intensity in the vicinity does not change (i.e., 1000 cm). －１ (No peak appears in this region.) Therefore, the Raman spectrum of the protective film was obtained, and the scattering intensity in each of the above-mentioned ranges was measured at 1000 cm². －１ By normalizing the scattering intensity, the state of the protective film can be understood.

[0028] Here, for convenience, the scattering intensity in each range (Raman shift) of the protective film's Raman spectrum is expressed as follows: 200 cm² －１ More than 350cm －１ The maximum scattering intensity within the following range is defined as "S ｍａｘ (200-350cm －１ It is written as ) . 460cm －１ More than 550cm －１ The maximum scattering intensity within the following range is "S ｍａｘ (460-550cm －１ It is written as ) 800cm－１ More than 1000cm －１ The maximum scattering intensity within the following range is "S ｍａｘ (800-1000cm －１ It is written as ) . 1000cm －１ The scattering intensity at "S (1000 cm)" is defined as "S (1000 cm) －１ It is written as )

[0029] 《S ｍａｘ (200-350cm －１ ) / S(1000cm －１ )》 The protective film of the first embodiment is S ｍａｘ (200-350cm －１ ) and S (1000cm －１ S is the ratio of ) ｍａｘ (200-350cm －１ ) / S(1000cm －１ The value is less than 1.000 or greater than 2.000. This indicates that the protective film is a fired product and not an unfired product (film precursor).

[0030] S ｍａｘ (200-350cm －１ ) / S(1000cm －１ Of the values ​​less than 1.000 and 2.000 or more, 2.000 or more is preferred.

[0031] S ｍａｘ (200-350cm －１ ) / S(1000cm －１ If the value is less than 1.000, it is preferably 0.990 or less, more preferably 0.980 or less, and even more preferably 0.970 or less. On the other hand, S ｍａｘ (200-350cm －１ ) / S(1000cm －１ If the value is less than 1.000, it is preferably 0.930 or higher, more preferably 0.940 or higher, and even more preferably 0.950 or higher.

[0032] Also, S ｍａｘ (200-350cm －１ ) / S(1000cm －１When it is 2,000 or more, 4,000 or more is preferable, 6,000 or more is more preferable, 8,000 or more is still more preferable, and 10,000 or more is particularly preferable. On the other hand, S ｍａｘ (200 - 350 cm －１ ) / S(1000 cm －１ ) When it is 2,000 or more, 16,000 or less is preferable, 14,000 or less is more preferable, and 12,000 or less is still more preferable.

[0033] For the protective film of the second embodiment, S ｍａｘ (200 - 350 cm －１ ) / S(1000 cm －１ ) is not particularly limited, but it is preferably in the same range as the first embodiment.

[0034] 《S ｍａｘ (460 - 550 cm －１ ) / S(1000 cm －１ )》 For the protective film (first to second embodiments), S ｍａｘ (460 - 550 cm －１ ) and S(1000 cm －１ ) The ratio S ｍａｘ (460 - 550 cm －１ ) / S(1000 cm<​​​​​​​​​​​​​​​​​​​​​​​​If the value is 2.000 or more, it is more preferably 3.000 or more, even more preferably 5.000 or more, and particularly preferably 7.000 or more. On the other hand, S ｍａｘ (460-550cm －１ ) / S(1000cm －１ If the value is 2,000 or more, it is more preferably 13,000 or less, even more preferably 11,000 or less, and particularly preferably 9,000 or less.

[0037] 《S ｍａｘ (800-1000cm －１ ) / S(1000cm －１ )》 The protective film (first and second embodiments) is S ｍａｘ (800-1000cm －１ ) and S (1000cm －１ S is the ratio of ) ｍａｘ (800-1000cm －１ ) / S(1000cm －１ It is preferable that the ratio is 1.048 or less or 1.500 or more, and more preferably 1.500 or more.

[0038] S ｍａｘ (800-1000cm －１ ) / S(1000cm －１ ) is more preferably 1.048 or less, even more preferably 1.047 or less, and particularly preferably 1.046 or less. On the other hand, S ｍａｘ (800-1000cm －１ ) / S(1000cm －１ If the value is 1.048 or less, it is more preferably 0.980 or more, even more preferably 1.000 or more, and particularly preferably 1.020 or more.

[0039] Also, S ｍａｘ (800-1000cm －１ ) / S(1000cm －１ ) is 1,500 or more, more preferably 2,000 or more, even more preferably 2,500 or more, and particularly preferably 3,000 or more. On the other hand, S ｍａｘ (800-1000cm －１ ) / S(1000cm －１If the value is 1,500 or more, it is more preferably 6,000 or less, even more preferably 5,000 or less, and particularly preferably 4,000 or less.

[0040] The Raman spectrum of the protective film is obtained by performing Raman spectroscopy measurements using a micro-laser Raman spectrometer (LabRAM HR800, Horiba, Ltd.) under the following conditions: • Excitation light wavelength: 532 nm • Excitation light irradiation diameter: 2.5 μm • Excitation light output: 400 mW • Slit width: 100 μm • Grating: 600 g / mm

[0041] <Nanoindentation Hardness> The protective film of the second embodiment has a nanoindentation hardness of 10.00 GPa or higher. This indicates that the protective film is a fired product and not an unfired product (film precursor). The protective film obtained by firing the film precursor is denser than the film precursor due to firing, and is therefore presumed to have higher hardness. The nanoindentation hardness of the protective film of the second embodiment is preferably 10.50 GPa or higher, more preferably 11.00 GPa or higher, and even more preferably 11.50 GPa or higher.

[0042] The nanoindentation hardness of the protective film of the first embodiment is, for example, 9.00 GPa or higher, preferably 9.50 GPa or higher, more preferably 10.00 GPa or higher, even more preferably 10.50 GPa or higher, particularly preferably 11.00 GPa or higher, and most preferably 11.50 GPa or higher.

[0043] There is no particular upper limit, and the nanoindentation hardness of the protective film (first to second embodiments) is, for example, 18.00 GPa or less, may be 16.00 GPa or less, or 14.00 GPa or less.

[0044] The nanoindentation hardness of the protective film is measured using a nanoindentation tester. More specifically, the nanoindentation hardness (unit: GPa) is measured by varying the load between 0 and 50 mN. Measurements are performed at 20 locations, and the average value is adopted as the nanoindentation hardness of the protective film. Other test conditions are as follows: A KLA iMicro nanoindentation tester is used, and the sample (protective film placed on the surface of the substrate) is fixed to its sample stage. For fixing the sample, a thermoplastic temporary adhesive "Crystalbond 555" (fluidization temperature: 48°C) manufactured by Alemco is used. As the actuator, an "inForce 50" that can be used with loads up to 50 mN is selected. As the indenter, a Berkovich indenter with a triangular pyramidal tip (tip radius of curvature: 20 nm) is used.

[0045] <Surface Roughness (Sa)> The surface roughness of the protective film is preferably 50.0 nm or less, more preferably 40.0 nm or less, even more preferably 30.0 nm or less, and particularly preferably 25.0 nm or less, with an arithmetic mean height Sa. On the other hand, there is no particular lower limit. The surface roughness (Sa) of the protective film is, for example, 5.0 nm or more, and may be 10.0 nm or more. The surface roughness (Sa) is measured in accordance with ISO 25178. The average of two measured values ​​is adopted as the value of surface roughness (Sa).

[0046] <Porosity> The porosity of the protective film is preferably less than 1.0 volume%, more preferably less than 0.40 volume%, even more preferably 0.30 volume% or less, even more preferably 0.20 volume% or less, and particularly preferably 0.10 volume% or less. The porosity of the protective film may be 0.00 volume% or more, and is often 0.001 volume% or more. When the film is formed by thermal spraying, the porosity of the protective film is often 0.40 volume% or more. By manufacturing the protective film using the method described later, the porosity can be adjusted to the above preferred range.

[0047] In this specification, the porosity of the protective film is determined as follows. First, using a focused ion beam (FIB), a slope is applied to the protective film and a portion of the substrate (described later) at a 52° angle in the thickness direction from the surface of the protective film toward the substrate, 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 a cross-sectional image is taken. Cross-sectional images are taken at multiple locations. Specifically, for example, if the protective film is circular, images are taken at a total of five points: one point in the center of the surface of the protective film and four points located 10 mm away from the outer edge, with the size of the cross-sectional image being 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 the 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 %). Note that 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.

[0048] <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 5.0 μm or more, and particularly preferably 10.0 μm or more. On the other hand, the thickness of the protective film is, for example, 300.0 μm or less, preferably 200.0 μm or less, more preferably 100.0 μm or less, even more preferably 50.0 μm or less, and particularly preferably 30.0 μm or less.

[0049] The thickness of the protective film is measured using a scanning electron microscope (SEM). More specifically, the cross-section of the protective film is observed, and the thickness of the protective film is measured at five arbitrary points. The average of these five measurements is then used as the thickness of the protective film (in μm).

[0050] [Components] Next, the components of this embodiment will be described. First, the components of this embodiment will be described in general terms based on Figure 1.

[0051] Figure 1 is a schematic cross-sectional view showing an example of member 1. As shown in Figure 1, in member 1, the protective film 2 is formed on the film-forming surface 3a, which is one surface of the substrate 3. That is, member 1 has the substrate 3 and the protective film 2 in this order. The protective film 2 used is the protective film of this embodiment described above. The substrate 3 will be described later.

[0052] <Base Material> The base material is appropriately selected according to the application of the component. The base material consists of at least one material selected from the group consisting of, for example, carbon (C), ceramics, and metals. Ceramics include, for example, glass (soda-lime glass, etc.), quartz, and 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). 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).

[0053] The shape of the base material is not particularly limited and can be flat, disc-shaped, ring-shaped, dome-shaped, concave, or convex, and can be appropriately selected depending on the application of the component. The base material may have through holes in part of it, or it may be chamfered.

[0054] As described above, the substrate has a surface (film-forming surface) on which a protective film is formed. The smaller the surface roughness of the film-forming surface of the substrate, the smaller the surface roughness of the protective film formed on the film-forming surface tends to be. For this reason, it is preferable that the film-forming surface of the substrate has a surface roughness (Sa) similar to that of the protective film that is formed.

[0055] <Applications of the components> The components are used, for example, as parts that make up plasma processing equipment, particularly as top plates and other components that make up the inner surface of the plasma processing equipment. Examples of plasma processing equipment include plasma etching equipment, plasma CVD equipment, plasma ALD equipment, and plasma modification equipment, and these devices are used, for example, in the manufacture of semiconductor devices. However, the applications are not limited to these.

[0056] [Method for Manufacturing the Protective Film and Components] Next, a method for manufacturing the protective film of this embodiment will be described. The following description also serves as a description of the method for manufacturing the components of this embodiment.

[0057] <Formation of the film precursor> First, a film precursor that will serve as a protective film is formed. The film precursor is an amorphous film containing Y, Al, and O, and has not undergone the calcination process described later. The composition (including the atomic ratio (Al / Y)) and thickness of the film precursor are preferably the same as those of the protective film to be obtained.

[0058] The film precursor is formed on the film-forming surface of the substrate using a film formation method such as sputtering or vapor deposition. Specific examples of film formation methods include DPDS (Digitally Processed DC Sputtering), reactive sputtering, IAD (Ion-Assisted Vapor Deposition), and ion plating. Among these, DPDS and IAD are preferred, with DPDS being more preferred.

[0059] The DPDS method is a method for obtaining a desired film by repeatedly alternating between forming a thin metal film and contacting the formed thin metal film with a reactive gas. By using the DPDS method, it is easy to obtain film precursors and protective films that meet the above requirements. Furthermore, the protective film obtained in the end is less prone to the formation of an altered layer after etching.

[0060] The following describes a method for forming a film precursor using the DPDS method. When forming a film precursor using the DPDS method, it is preferable to alternately repeat the formation of a metal thin film (a film containing metallic yttrium and metallic aluminum) and the oxidation of the formed metal thin film. The formation of the metal thin film and the oxidation of the metal thin film may be carried out using separate chambers (not shown).

[0061] Specifically, for example, first, a substrate is placed in a first chamber with an inert gas atmosphere (e.g., argon gas). Then, a metal thin film is formed on the deposition surface of the substrate using a sputtering target made of metallic yttrium and a sputtering target made of metallic aluminum. The thickness of the metal thin film in a single formation is, for example, sub-nm (less than 1.0 nm).

[0062] Next, the substrate on which the metal thin film is formed is transferred to a second chamber with a mixed gas atmosphere of inert gas and oxygen gas to oxidize the metal thin film. The ratio of the amount of oxygen gas supplied to the total amount of inert gas and oxygen gas supplied (hereinafter referred to as the "oxygen gas ratio") is adjusted as appropriate, but may be, for example, 20% by volume or more, or 30% by volume or more. On the other hand, the oxygen gas ratio may be, for example, 80% by volume or less, or 70% by volume or less.

[0063] When forming and oxidizing metal thin films, for example, a plasma is generated by applying an electric field between the anode and cathode in the chamber while controlling the pressure inside the chamber to 0.2 to 0.4 Pa, and sputtering is performed. By repeatedly alternating between forming and oxidizing metal thin films and stacking the oxidized metal thin films to a desired thickness, a film precursor containing Y, Al, and O is formed.

[0064] <Castration of the film precursor> Next, a protective film is obtained by calcining the film precursor. The atmosphere used when calcining the film precursor (calcination atmosphere) is, for example, an atmospheric atmosphere. The temperature used when calcining the film precursor (calcination temperature) is, for example, 200°C or higher, preferably 300°C or higher, and may be 400°C or higher, or 500°C or higher. On the other hand, from the viewpoint of not crystallizing the film precursor, the calcination temperature is preferably less than 1000°C, more preferably 900°C or lower, even more preferably 800°C or lower, and particularly preferably 700°C or lower.

[0065] The time for firing the film precursor at the firing temperature (firing time) is, for example, 1 hour or more, preferably 2 hours or more, and more preferably 3 hours or more. On the other hand, the firing time may be, for example, 8 hours or less, and may be 5 hours or less.

[0066] When calcining the film precursor, the film precursor is heated, for example, from room temperature to the calcination temperature, and then cooled. The heating rate and cooling rate are preferably 1°C / min or more, and more preferably 3°C / min or more. Furthermore, the heating rate and cooling rate are preferably 10°C / min or less, and more preferably 7°C / min or less.

[0067] At this time, by firing the film precursor together with the substrate, a component comprising a protective film and a substrate is obtained. Since the obtained component has excellent plasma resistance, it is suitably used as a component that constitutes the inner surface of a plasma processing apparatus, as described above.

[0068] 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 2 and 3 are examples, and Examples 1 and 4 are comparative examples.

[0069] <Manufacturing of Components> A film precursor (thickness: 10 μm) containing Y, Al, and O was formed on the film-forming surface of a flat substrate (material: aluminum oxide, surface roughness Sa of the film-forming surface: 30.0 nm) using a sputtering apparatus (RAS-1100BII, manufactured by Synchron Corporation) by the DPDS method described above. At this time, argon gas was used as the inert gas, the oxygen gas ratio was set to 50% by volume, and the pressure in the chamber was controlled to 0.3 Pa.

[0070] Next, using an electric furnace, the film precursor together with the substrate was fired at the firing temperature shown in Table 1 below under atmospheric conditions to form a protective film (thickness: 10 μm) containing Y, Al, and O. The firing time was 3 hours, the heating rate was 5°C / min, and the cooling rate was 5°C / min. Thus, a component consisting of the protective film and the substrate was obtained.

[0071] However, in Example 1, the film precursor was not calcined. Therefore, "-" is written in the "Casting Temperature" column of Table 1 below. The protective film in Example 1 is an uncalcined product (still a film precursor), but for convenience, it is referred to as a protective film.

[0072] The items listed in Table 1 below were determined for the formed protective film using the method described above. The results are shown in Table 1 below. For the YAP(121) peak, if no peak with a full width at half maximum (FMAX) of less than 1° existed, "A" was written in the "YAP(121) peak" column in Table 1 below. If a peak with a FMAX of less than 1° existed, "B" was written. The same applies to the YAG(420) peak and the YAM(112) peak.

[0073] <Etching Amount (Plasma Resistance)> The plasma resistance of the manufactured component was evaluated by plasma etching of the protective film. More specifically, first, the component was cut to a size of 20 mm x 20 mm x 2 mm so that the surface size of the protective film was 20 mm x 20 mm. Next, half of the surface was covered with a polyimide tape (P-222, manufactured by Nitto Denko Corporation) with a total thickness of 100 μm. In this way, a sample was prepared. After that, the sample was placed on the stage of a plasma etching apparatus (EXAM, manufactured by Shinko Seiki Co., Ltd.) and subjected to CF ４ / O ２Plasma etching was performed using a mixed gas of / Ar. The output power was 550W, the pressure was 3Pa, and the etching time was 60 minutes. After etching, the polyimide tape was removed, and the distance of the step between the coated surface and the exposed surface was measured using a stylus-type surface profile measuring instrument (Dektak-XT, ULVAC, Inc.). Measurements were taken at three points, and the average value of the three points was calculated as the etching amount (unit: nm). The results are shown in Table 1 below. A smaller etching amount indicates better plasma resistance.

[0074]

[0075] <Summary of Evaluation Results> As shown in Table 1 above, the protective films of Example 2 and Example 3 exhibited less etching and superior plasma resistance compared to Examples 1 and 4. Furthermore, when the porosity of Examples 2 and 3 was measured according to the method described above, it was found to be less than 1.0 volume%.

[0076] Furthermore, the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2025-005883, filed on January 16, 2025, are incorporated herein by reference as disclosure of the present invention.

[0077] 1: Component 2: Protective film 3: Substrate 3a: Film-forming surface

Claims

1. Contains yttrium, aluminum, and oxygen, and in the X-ray diffraction pattern, YAlO ３ The (121) plane does not have a peak, or YAlO ３ The full width at half maximum of the peak of the (121) plane is 1° or more, and in the Raman spectrum, at 200 cm² －１ More than 350cm －１ The maximum scattering intensity in the following range and 1000 cm －１ A protective film in which the ratio of scattering intensity at a given point is less than 1.000 or greater than 2.

000.

2. The protective film according to claim 1, wherein the atomic ratio Al / Y of yttrium to aluminum is 0.40 or more and 2.00 or less.

3. The protective film according to claim 1, wherein the nanoindentation hardness is 9.00 GPa or higher.

4. The protective film according to claim 1, wherein the surface roughness is 50.0 nm or less in arithmetic mean height Sa.

5. In the X-ray diffraction pattern, there is no peak of the (420) plane of Y ３ Al ５ O １２ or the half-value width of the peak of the (420) plane of Y ３ Al ５ O １２ is 1° or more. The protective film according to claim 1.

6. Contains yttrium, aluminum, and oxygen, and in the X-ray diffraction pattern, YAlO ３ The (121) plane does not have a peak, or YAlO ３ A protective film having a peak width at half maximum of 1° or more on the (121) plane and a nanoindentation hardness of 10.00 GPa or more.

7. The protective film according to claim 6, wherein the atomic ratio Al / Y of yttrium to aluminum is 1.30 or more and 2.00 or less.

8. In the aforementioned X-ray diffraction pattern, Y ３ Al ５ O １２ The peak on the (420) plane does not exist, or Y ３ Al ５ O １２ The protective film according to claim 6, wherein the full width at half maximum of the (420) plane peak is 1° or more.

9. A member comprising, in this order, a base material and a protective film according to any one of claims 1 to 8.

10. A plasma processing apparatus comprising the member described in claim 9 as a component constituting the inner surface.

11. Contains yttrium, aluminum, and oxygen, and in the X-ray diffraction pattern, YAlO ３ The (121) plane does not have a peak, or YAlO ３ A method for producing a protective film having a peak width at half maximum of 1° or more on the (121) plane, comprising: forming a film precursor containing yttrium, aluminum, and oxygen; and obtaining the protective film by calcining the film precursor.

12. The method for producing a protective film according to claim 11, wherein the film precursor is fired at a temperature of 300°C or higher.

13. The method for producing a protective film according to claim 12, wherein the film precursor is calcined for three hours or more.

14. The method for producing a protective film according to claim 11, wherein the film precursor is formed by sputtering or vapor deposition.

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