Yttrium-based protective film, member, and plasma processing device

Abstract

Provided is an yttrium-based protective film having excellent plasma resistance.　The present invention provides an yttrium-based protective film that contains yttrium and oxygen and that has an optical band gap of 5.0 eV or less. In a Raman spectrum of the yttrium-based protective film, the half-value width of a peak having a peak top in the range of 833-837 cm-1 is preferably 100 cm-1 or less.<sp / > In the yttrium-based protective film, the content ratio of yttrium to the total of yttrium and oxygen is preferably 35-45 atom%. In the yttrium-based protective film, the content ratio of oxygen to the total of yttrium and oxygen is preferably 55-65 atom%.

Description

Yttrium protective film, components, and plasma processing apparatus

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

[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, yttrium protective films have been used to protect parts exposed to plasma, and Patent Document 1 discloses a "film mainly composed of yttrium oxide."

[0005] International Publication No. 2019 / 160121

[0006] The inventors of this invention investigated and found that conventional yttrium 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 yttrium 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

[11] : [1] A yttrium protective film containing yttrium and oxygen, with an optical band gap of 5.0 eV or less. [2] In the Raman spectrum, 833 cm⁻¹ －１ 837cm or more －１ The peak with a peak top within the following range has a full width at half maximum of 100 cm. －１The yttrium protective film described in [1] above, which is as follows: [3] The yttrium protective film described in [1] or [2] above, wherein the yttrium content relative to the total of yttrium and oxygen is 35 atomic% or more and 45 atomic% or less. [4] The yttrium protective film described in any of [1] to [3] above, wherein the oxygen content relative to the total of yttrium and oxygen is 55 atomic% or more and 65 atomic% or less. [5] The yttrium protective film described in any of [1] to [4] above, which further contains at least one element selected from the group consisting of scandium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. [6] L ＊ The value is less than 89, a ＊ The value is -2 or greater, b ＊ [1] to [2] above: A yttrium protective film according to any one of [1] to [5] above, wherein the value is -2 or greater. [7] A yttrium protective film according to any one of [1] to [6] above, wherein the EELS peak intensity ratio is less than 1.00. [8] A yttrium protective film according to any one of [1] to [7] above, wherein the nanoindentation hardness is 3.0 GPa or greater. [9] A yttrium protective film according to any one of [1] to [8] above, wherein the surface roughness is 40.00 nm or less in arithmetic mean height Sa.

[10] A yttrium protective film according to any one of [1] to [9] above, wherein the film thickness is 1.0 μm or more and 100.0 μm or less.

[11] A component comprising a substrate and a yttrium protective film according to any one of [1] to [9] above, in this order.

[12] A plasma processing apparatus comprising the component according to

[11] above as a component constituting the inner surface.

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

[0010] This is a schematic diagram 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] [Yttrium Protective Film] The yttrium protective film of this embodiment contains yttrium and oxygen, and has an optical band gap of 5.0 eV or less. The yttrium protective film of this embodiment has excellent plasma resistance. The reason for this is not clear, but it is presumed to be as follows.

[0013] The yttrium protective film of this embodiment contains yttrium and oxygen. That is, it contains yttrium oxide, but the optical band gap of the yttrium protective film of this embodiment is Y ２ O ３ This is smaller than the normal optical band gap (approximately 5.8 eV). This indicates that the yttrium oxide constituting the yttrium protective film in this embodiment is a suboxide and is unoriented (non-crystallized), which suppresses embrittlement and, as a result, provides excellent plasma resistance.

[0014] The yttrium protective film of this embodiment will be described in more detail below.

[0015] <Optical Bandgap> The optical bandgap of the yttrium protective film in this embodiment is 5.0 eV or less, preferably 4.7 eV or less, more preferably 4.3 eV or less, even more preferably 3.8 eV or less, and particularly preferably 3.4 eV or less, for the reason that it provides better plasma resistance. On the other hand, the optical bandgap of the yttrium protective film in this embodiment may be, for example, 2.8 eV or more, and may also be 3.0 eV or more.

[0016] The optical band gap of the yttrium-based protective film is determined by plotting the dependence of the absorption coefficient on the reciprocal of the light energy. Specifically, the optical band gap of the yttrium-based protective film is determined as follows. First, the transmittance spectrum (vertical axis: transmittance T (unit: %), horizontal axis: wavelength (unit: nm)) and reflectance spectrum (vertical axis: reflectance R (unit: %), horizontal axis: wavelength (unit: nm)) of the yttrium-based protective film are determined under the following conditions. - Measuring device: ultraviolet-visible near-infrared spectrophotometer (V-770, manufactured by JASCO Corporation) - Measuring wavelength range: 300 to 600 nm - Scanning speed: 400 nm / min - Incident angle: 5 degrees - Detection angle: 0 degrees. In addition, for example, when the substrate on which the yttrium-based protective film is disposed is ceramics or the like (a substance that causes scattering or the like), it is difficult to measure the spectrum by the transmission method, so the total reflection measurement method (ATR method) is used. However, when the yttrium-based protective film has a certain film thickness, the yttrium-based protective film may be peeled off from the substrate and thinned, and then the spectrum may be measured using the transmission method.

[0017] Next, the film thickness d (unit: cm) of the yttrium-based protective film is determined under the following conditions. - Measuring device: stylus surface profiler (Dektak-XT, manufactured by Bruker Corporation) - Scanning speed: 10 seconds - Scanning distance: 1000 μm - Measuring range: 6.5 μm

[0018] Then, based on the following formula obtained by transforming the Lambert-Beer law, the absorption coefficient α is determined to obtain an absorption coefficient spectrum. α = (1 / d) log((100 - R) / T)

[0019] After that, a spectrum is created with the logarithm of the absorption coefficient α on the vertical axis and the reciprocal 1 / E (unit: eV －１ ) of the energy E (= hc / λ) on the horizontal axis. A straight line L1 passing through the points of 1 / E = 0.25 eV －１ and 1 / E = 0.28 eV －１ and a straight line L2 parallel to the horizontal axis passing through the point of 1 / E = 0.4 eV are added to the created spectrum. Then, the value of 1 / E of the spectrum at the intersection of the straight line L1 and the straight line L2 is read, and its reciprocal is obtained as the optical band gap (unit: eV).

[0020] <EELS Peak Intensity Ratio> For yttrium protective films, an EELS spectrum (vertical axis: intensity, horizontal axis: energy loss (unit: eV)) is obtained by measurement using electron energy loss spectroscopy (EELS). In the EELS spectrum of the yttrium protective film, the intensity of the peak appearing near 37 eV (a peak attributed to the transition between shallow core levels and unoccupied conduction band levels) is I Ａ And the intensity of the peak around 15 eV (a peak attributed to the transition between the valence band and the conduction band) I Ｂ Ratio to (I B / I A This is called the "EELS peak intensity ratio." In other words, the EELS peak intensity ratio is the intensity of the peak that appears around 37 eV in the EELS spectrum obtained by measurement using electron energy loss spectroscopy. Ａ The intensity of the peak around 15 eV relative to this is I Ｂ It is the ratio of .

[0021] For the reason of superior plasma resistance, the EELS peak intensity ratio is preferably less than 1.00, more preferably 0.95 or less, and even more preferably 0.90 or less. On the other hand, the EELS peak intensity ratio is, for example, 0.40 or more, may be 0.50 or more, may be 0.60 or more, or may be 0.65 or more.

[0022] The EELS peak intensity ratio of the yttrium-based protective film is determined as follows using an analytical technique (STEM-EELS) that combines a scanning transmission electron microscope (STEM) and EELS. First, a 50-nm-thick C (carbon) coat and a 10-nm-thick Pt (platinum) coat are formed on the surface of the yttrium-based protective film, and then a 70-nm-thick thin film sample is prepared using a focused ion beam (FIB) apparatus (Helios 1200, manufactured by Thermo Fisher Scientific). Next, for the prepared sample, TEM observation (sample observation in TEM mode) and STEM observation (sample observation in STEM mode) are carried out using a STEM apparatus (NEOARM, manufactured by JEOL Ltd.) under the following conditions, and then EELS measurement is carried out under the following conditions. 《TEM Observation Conditions》 - Accelerating voltage: 80 kV - Emission current: 5 μA 《STEM Observation Conditions》 - Probe size: 6C - Second condenser lens aperture: 30 μm - Detector: Gatan-ADF - Camera length: 2 cm 《EELS Measurement Conditions》 - Dispersion: 50 meV / ch - Aperture: 5 mm - Step size: 10 nm - Mapping area: 48×100 pixels・Exposure: 0.02 s / steps - Pass: 1 - FWHM (ZLP): 0.45 eV

[0023] 〈Composition〉 The yttrium-based protective film contains yttrium (Y) and oxygen (O). The total content of Y and O in the yttrium-based protective film is preferably 85 atomic% or more, more preferably 90 atomic% or more, and still more preferably 95 atomic% or more. The upper limit is not particularly limited and may be 100 atomic%. When the yttrium-based protective film is manufactured by the method described later, it shall satisfy the above composition.

[0024] The yttrium-based protective film contains, for example, yttrium oxide. Y ２ O ３Theoretically, the Y and O content in yttrium oxide, represented by [formula], is 40 atomic% and 60 atomic%. Therefore, in the yttrium protective film, the ratio of Y to the total of Y and O (hereinafter referred to as "Y / (Y+O)") may be, for example, 35 atomic% or more, 38 atomic% or more, or, for example, 45 atomic% or less, or 42 atomic% or less. Also, in the yttrium protective film, the ratio of O to the total of Y and O (hereinafter referred to as "O / (Y+O)") may be, for example, 55 atomic% or more, 58 atomic% or more, or, for example, 65 atomic% or less, or 62 atomic% or less.

[0025] However, yttrium oxide produced by the method described later tends to be a suboxide. That is, the yttrium oxide contained in the yttrium protective film of this embodiment tends to have a higher Y content and a lower O content than the theoretical values. For this reason, in the yttrium protective film, Y / (Y+O) may be 41 atomic percent or more. Also, in the yttrium protective film, O / (Y+O) may be 59 atomic percent or less.

[0026] The yttrium protective film may contain, in addition to Y and O, other rare earth elements other than Y. That is, the yttrium protective film may contain at least one element selected from the group consisting of scandium (Sc), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu) (hereinafter referred to as "additive element"). The content of the additive element in the yttrium protective film is preferably 5 atomic percent or less, more preferably 3 atomic percent or less, even more preferably 1 atomic percent or less, and may be 0 atomic percent.

[0027] The content of each element in the yttrium protective film is determined using an energy-dispersive X-ray analyzer (EDX) attached to a scanning electron microscope (SEM).

[0028] <Raman Spectrum> If the sub-oxidation of yttrium oxide is progressing, the Raman spectrum will show 833 cm⁻¹. －１ 837cm or more －１ A peak with a peak top within the following range (hereinafter referred to as the "sub-oxide peak") appears. The sharper the sub-oxide peak, the more advanced the sub-oxide, and consequently the non-orientation (acrystalline) process, resulting in superior plasma resistance. For this reason, the presence of a sub-oxide peak in the Raman spectrum of a yttrium protective film is preferable. Furthermore, if a sub-oxide peak is present, its full width at half maximum (FMAX) is 100 cm². －１ The following is preferable: 95 cm －１ The following is more preferable: 90 cm －１ The following is even more preferable: 85 cm －１ The following limits may also apply. The lower limit is not particularly limited, and the full width at half maximum of the sub-oxidative peak can be, for example, 75 cm. －１ That's all.

[0029] The Raman spectrum of the yttrium 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

[0030] <L ＊ a ＊ b ＊ > Next, the yttrium protective film L ＊ Value, a ＊ Value and b ＊ Let's explain the value. L ＊ Value, a ＊ Value and b ＊ The values ​​are, respectively, CIE1976L ＊ a ＊ b ＊ L in color space ＊ a ＊ and b ＊ Therefore, measurements are taken using a spectrophotometer (CM-5, manufactured by Konica Minolta) with the SCE (Specular Reflectance Rejection) method and a D65 light source.

[0031] L ＊ The value is, for example, 90 or less, preferably less than 89, more preferably 85 or less, even more preferably 70 or less, particularly preferably 50 or less, and most preferably 35 or less. On the other hand, regarding the lower limit, L ＊ The value is, for example, 10 or more, preferably 15 or more, and more preferably 20 or more.

[0032] a ＊ The value is, for example, -5 or greater, preferably -2 or greater, more preferably 1 or greater, even more preferably 5 or greater, particularly preferably 10 or greater, and most preferably 15 or greater. On the other hand, regarding the upper limit, a ＊ The value is, for example, 35 or less, preferably 30 or less, and more preferably 25 or less.

[0033] b ＊ The value is, for example, -5 or greater, preferably -2 or greater, more preferably 1 or greater, even more preferably 8 or greater, particularly preferably 17 or greater, and most preferably 25 or greater. On the other hand, regarding the upper limit, b ＊ The value is, for example, 50 or less, preferably 45 or less, and more preferably 40 or less.

[0034] <Nanoindentation Hardness> The nanoindentation hardness of the yttrium protective film is preferably 3.0 GPa or higher, more preferably 4.5 GPa or higher, even more preferably 6.0 GPa or higher, particularly preferably 7.5 GPa or higher, and most preferably 9.0 GPa or higher, because it provides superior plasma resistance. In this case, the yttrium protective film is densified, and therefore is presumed to have high hardness. There is no particular upper limit, and the nanoindentation hardness of the yttrium protective film may be, for example, 14.0 GPa or less, 12.0 GPa or less, or 10.0 GPa or less.

[0035] The nanoindentation hardness of the yttrium protective film is measured using a nanoindentation tester, varying the load between 0 and 50 mN. Measurements are taken at 20 locations, and the average value is adopted as the nanoindentation hardness. Other test conditions are as follows: A KLA iMicro nanoindentation tester is used, and the sample (yttrium protective film placed on the surface of the substrate) is fixed to its sample stage. For sample fixation, 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.

[0036] <Surface Roughness (Sa)> The surface roughness of the yttrium protective film is, for example, 50.00 nm or less in arithmetic mean height Sa, preferably 40.00 nm or less, more preferably 30.00 nm or less, even more preferably 25.00 nm or less, and particularly preferably 20.00 nm or less. On the other hand, the surface roughness (Sa) of the yttrium protective film is, for example, 5.00 nm or more, and may be 10.00 nm or more. The surface roughness (Sa) is measured in accordance with ISO 25178 using a VK-X3000 (manufactured by Keyence Corporation). The average of two measured values ​​is adopted as the surface roughness (Sa) value.

[0037] <Porosity> The porosity of the yttrium protective film is preferably less than 0.40 volume%, 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 yttrium 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 yttrium protective film is often 0.40 volume% or more. By manufacturing the yttrium protective film using the method described later, the porosity can be adjusted to the above preferred range.

[0038] In this specification, the porosity of the yttrium protective film is determined as follows. First, using a focused ion beam (FIB), a slope is applied to the yttrium protective film and a portion of the substrate described later, at a 52° angle in the thickness direction from the surface of the yttrium protective film toward the substrate, to expose 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 yttrium protective film is circular, images are taken at a total of five points: one point in the center of the surface of the yttrium 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 yttrium protective film is 5 μm or more, cross-sectional images are taken at multiple locations so that the entire cross-section of the yttrium 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 yttrium protective film is calculated and considered to be the porosity (unit: volume %) of the yttrium protective film. 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.

[0039] <Film Thickness> The film thickness of the yttrium 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 film thickness of the yttrium 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. The method for measuring the film thickness of the yttrium protective film is as described in the section on measuring the optical band gap.

[0040] [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.

[0041] Figure 1 is a schematic diagram showing an example of member 1. As shown in Figure 1, in member 1, the yttrium 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 yttrium protective film 2 in this order. The yttrium protective film of this embodiment described above is used as the yttrium protective film 2. The substrate 3 will be described later.

[0042] <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).

[0043] 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.

[0044] As described above, the substrate has a surface (film-forming surface) on which the yttrium protective film is formed. The smaller the surface roughness of the film-forming surface of the substrate, the smaller the surface roughness of the yttrium 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 yttrium protective film that is formed.

[0045] <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.

[0046] [Method for Manufacturing the Yttrium Protective Film and Components] Next, a method for manufacturing the yttrium 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.

[0047] The yttrium protective film is formed on the film-forming surface of the substrate using a film-forming method such as sputtering or vapor deposition. Specific examples of film-forming 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.

[0048] 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 a yttrium protective film that satisfies the above requirements. Furthermore, the resulting yttrium protective film is less prone to the formation of an altered layer after etching.

[0049] The following describes a method for forming a yttrium protective film using the DPDS method. When forming a yttrium protective film using the DPDS method, it is preferable to alternately repeat the formation of a metal thin film (a film containing metallic yttrium) 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).

[0050] 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. The thickness of the metal thin film in a single formation is, for example, sub-nm (less than 1.0 nm).

[0051] 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.

[0052] 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 temperature and pressure inside the chamber, and then sputtering is performed.

[0053] The temperature inside the chamber is, for example, 180°C or lower, preferably 150°C or lower, more preferably 120°C or lower, and even more preferably 100°C or lower. On the other hand, the temperature inside the chamber is, for example, 10°C or higher, and may be 20°C or higher.

[0054] The pressure inside the chamber is preferably 0.20 Pa or less, more preferably 0.15 Pa or less, even more preferably 0.12 Pa or less, and particularly preferably 0.10 Pa or less. On the other hand, the pressure inside the chamber is, for example, 0.01 Pa or more.

[0055] Examples of plasma types include capacitively coupled plasma (CCP), inductively coupled plasma (ICP), and electron cyclotron resonance plasma (ECR plasma), with CCP or ICP being preferred, and CCP being more preferred.

[0056] By repeatedly forming and oxidizing thin metal films alternately, and by stacking the oxidized thin metal films to a desired thickness, a yttrium-based protective film containing Y and O is formed.

[0057] Thus, a component comprising a yttrium protective film and a substrate is obtained. Because the obtained component has excellent plasma resistance, it is suitably used as a component constituting the inner surface of a plasma processing apparatus, as described above.

[0058] 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 4 are examples, and Example 5 is a comparative example.

[0059] <Manufacturing of Components> A yttrium protective film containing Y and O (film thickness: 10 μm) was formed on the film-forming surface of a flat substrate (material: aluminum oxide, surface roughness Sa of the film-forming surface: 40.00 nm) using a sputtering apparatus (CCS-2800, manufactured by Shibaura Mechatronics Co., Ltd.) by the DPDS method described above. At this time, argon gas was used as the inert gas, and the oxygen gas ratio was 50 volume%. The types of plasma (CCP or ICP) shown in Table 1 below were generated, and the temperature and pressure in the chamber were controlled to the values ​​shown in Table 1 below. Two sputtering apparatuses were prepared: one equipped with a plasma gun for generating CCP and another equipped with a plasma gun for generating ICP, and either was used depending on the type of plasma to be generated. In this way, components consisting of a yttrium protective film and a substrate were obtained.

[0060] In all examples, the total content of Y and O in the formed yttrium protective film was 99 atomic percent or more.

[0061] The items listed in Table 1 below were determined for the formed yttrium protective film using the method described above. The results are shown in Table 1 below. In the Raman spectrum, if no sub-oxide peak was present, "-" was entered in the "Full width at half maximum of sub-oxide peak" column.

[0062] <Etching Amount (Plasma Resistance)> The plasma resistance was evaluated by plasma etching of the formed yttrium protective film. More specifically, first, the material was cut to a size of 20 mm x 20 mm x 2 mm so that the surface size of the yttrium protective film would be 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 the plasma etching apparatus and CF ４ / O ２ Plasma (CCP) was generated using a mixed gas of / Ar (mixing ratio: 40 / 10 / 50) and etching was performed. The output power was 550W, the pressure was 3Pa, and the etching time was 60 minutes. An EXAM (manufactured by Shinko Seiki Co., Ltd.) was used as the plasma etching apparatus to generate the CCP. After etching, the polyimide tape was removed, and the distance of the step difference between the coated surface and the exposed surface was measured using a stylus-type surface shape measuring instrument (Dektak-XT, manufactured by Bruker). Measurements were performed at three points, and the average value of the three points was calculated as the etching amount (unit: μm). The results are shown in Table 1 below. A smaller etching amount indicates better plasma resistance.

[0063]

[0064] <Summary of Evaluation Results> As shown in Table 1 above, the yttrium protective films of Examples 1 to 4 were found to have less etching and superior plasma resistance than Example 5. Furthermore, when the porosity of the yttrium protective films of Examples 1 to 4 was measured according to the method described above, it was less than 0.10 volume%. The entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2025-010808, filed on January 24, 2025, are incorporated herein by reference as disclosure of the present invention.

[0065] 1: Component 2: Yttrium protective film 3: Substrate 3a: Film-forming surface

Claims

1. A yttrium-based protective film containing yttrium and oxygen, with an optical band gap of 5.0 eV or less.

2. In the Raman spectrum, 833 cm⁻¹ －１ 837cm or more －１ The peak with a peak top within the following range has a full width at half maximum of 100 cm. －１ The yttrium protective film according to claim 1, which is as follows:

3. The yttrium protective film according to claim 1, wherein the yttrium content relative to the total amount of yttrium and oxygen is 35 atomic% or more and 45 atomic% or less.

4. The yttrium protective film according to claim 1, wherein the oxygen content relative to the total amount of yttrium and oxygen is 55 atomic% or more and 65 atomic% or less.

5. The yttrium protective film according to claim 1, further comprising at least one element selected from the group consisting of scandium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.

6. L ＊ The value is less than 89, a ＊ The value is -2 or greater, b ＊ The yttrium protective film according to claim 1, wherein the value is -2 or greater.

7. The yttrium protective film according to claim 1, wherein the EELS peak intensity ratio is less than 1.

00.

8. The yttrium protective film according to claim 1, wherein the nanoindentation hardness is 3.0 GPa or higher.

9. The yttrium protective film according to claim 1, wherein the surface roughness is 40.00 nm or less in arithmetic mean height Sa.

10. The yttrium protective film according to claim 1, wherein the film thickness is 1.0 μm or more and 100.0 μm or less.

11. A component comprising, in this order, a base material and a yttrium protective film according to any one of claims 1 to 10.

12. A plasma processing apparatus comprising the member described in claim 11 as a component constituting the inner surface.

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