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

Abstract

The present invention provides a yttrium-based protective film which exhibits excellent plasma resistance.　This yttrium-based protective film contains yttrium, oxygen and fluorine, and exhibits a rate of variation in yttrium content of 5.0% or less at a depth of 8-30nm in an elemental profile in the film thickness direction as measured by Rutherford backscattering spectrometry.

Description

Yttrium protective film, components, and plasma processing apparatus

[0001] The present invention relates to a yttrium protective film. The present invention also relates to a component comprising the above-mentioned yttrium protective film, and a plasma processing apparatus comprising the above-mentioned component.

[0002] Plasma-based processing is sometimes used when manufacturing semiconductor devices. For example, the surface of a semiconductor substrate (silicon wafer) may be micro-processed by dry etching using halogen-based gas plasma in a chamber, or the chamber may be cleaned using oxygen gas plasma after the semiconductor substrate has been removed following dry etching.

[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 a yttrium-based protective film containing yttrium (Y), oxygen (O), and fluorine (F), exhibiting a predetermined peak intensity ratio.

[0005] Japanese Patent Publication No. 2023-120943

[0006] With the increasing density and resolution of semiconductor circuits in recent years, etching has sometimes been performed under different etching conditions. When the present inventors formed a yttrium protective film by referring to the technology described in Patent Document 1, they found that there was room for improvement in plasma resistance (corrosion resistance to plasma).

[0007] This invention has been made in view of the above problems, and aims to provide a yttrium protective film with excellent plasma resistance. Furthermore, this invention also aims to provide a component and a plasma processing apparatus.

[0008] As a result of diligent research into the above-mentioned problems, the inventors of the present invention discovered that when the rate of variation of yttrium content in the film thickness direction is within a predetermined range, the material exhibits excellent plasma resistance, leading to the completion of the present invention.

[0009] That is, the present inventors have found that the above problems can be solved by the following configurations. [1] A yttrium-based protective film containing yttrium, oxygen, and fluorine, wherein in the elemental profile in the film thickness direction measured by Rutherford backscattering spectrometry, the rate of variation of the yttrium content is 5.0% or less at a depth of 8 to 30 nm. [2] In the X-ray diffraction chart obtained by performing X-ray diffraction measurement, the full width at half maximum of the 151 diffraction peak of Y ５ O ４ F ７ is 0.2° or more in 2θ, the yttrium-based protective film according to [1]. [3] In the Raman scattering spectrum, no peak is observed near 320 cm －１ or, when a peak is observed near 320 cm －１ , the full width at half maximum of the peak near 320 cm －１ is 35 cm －１ or more, the yttrium-based protective film according to [1] or [2]. [4] In the Raman scattering spectrum, no peak is observed near 500 cm －１ or, when a peak is observed near 500 cm －１ , the full width at half maximum of the peak near 500 cm －１ is 35 cm －１The yttrium protective film described in any one of [1] to [3] above. [5] The yttrium protective film described in any one of [1] to [4], wherein the yttrium content is 15.0 to 35.0 atomic percent relative to the total atoms of the yttrium protective film. [6] The yttrium protective film described in any one of [1] to [5], wherein the oxygen content is 30.0 to 40.0 atomic percent relative to the total atoms of the yttrium protective film. [7] The yttrium protective film described in any one of [1] to [6], wherein the fluorine content is 35.0 to 55.0 atomic percent relative to the total atoms of the yttrium protective film. [8] A yttrium protective film according to any one of [1] to [7], 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. [9] A yttrium protective film according to any one of [1] to [8], having a nanoindentation hardness of 5.00 GPa or more.

[10] A yttrium protective film according to any one of [1] to [9], having a surface roughness of 50.00 nm or less in arithmetic mean height Sa.

[11] A yttrium protective film according to any one of [1] to

[10] , having a film thickness of 1.0 μm or more and 100.0 μm or less.

[12] A component comprising a substrate and a yttrium protective film as described in any one of [1] to

[11] .

[13] A plasma processing apparatus comprising the component described in

[12] as a component constituting the inner surface.

[0010] According to the present invention, a yttrium-based protective film with plasma resistance can be provided. Furthermore, according to the present invention, a component and a plasma processing apparatus can also be provided.

[0011] This is a schematic cross-sectional view showing an example of a component.

[0012] The meanings of terms used in this invention are as follows: A numerical range expressed using "~" means a range that includes the numbers written before and after "~" as the lower and upper limits. The present invention will now be described in detail. The following descriptions of constituent elements may be based on typical embodiments of the present invention, but the present invention is not limited to such embodiments.

[0013] [Yttrium-based protective film] The yttrium-based protective film of the present invention (hereinafter also referred to as "the protective film of the present invention") contains yttrium, oxygen, and fluorine, and the variation rate of the yttrium content in the elemental profile in the film thickness direction measured by Rutherford backscattering is 5.0% or less at a depth of 8 to 30 nm. The mechanism by which the protective film of the present invention exhibits excellent plasma resistance is not entirely clear, but the inventors speculate as follows.

[0014] The fluctuation rate of the yttrium (Y) content mentioned above will be explained in detail later, but the fluctuation rate corresponds to fluctuations in the Y content. When the fluctuation in the Y content is small, it corresponds to the uniform combination of Y with oxygen (O) and fluorine (F) contained in the protective film of the present invention, and since the chemical bond is strong, it is thought to have excellent plasma resistance.

[0015] The protective film of the present invention will be described in detail below.

[0016] <Composition> The protective film of the present invention contains yttrium (Y), oxygen (O), and fluorine (F). The content of Y is preferably 15.0 atomic% or more, more preferably 18.0 atomic% or more, even more preferably 20.0 atomic% or more, and particularly preferably 22.0 atomic% or more, relative to the total atoms of the protective film of the present invention. The content of Y is preferably 35.0 atomic% or less, more preferably 32.0 atomic% or less, even more preferably 30.0 atomic% or less, and particularly preferably 28.0 atomic% or less, relative to the total atoms of the protective film of the present invention. The content of O is preferably 15.0 atomic% or more, more preferably 20.0 atomic% or more, even more preferably 23.0 atomic% or more, and particularly preferably 24.0 atomic% or more, relative to the total atoms of the protective film of the present invention. The content of O is preferably 40.0 atomic% or less, more preferably 39.0 atomic% or less, even more preferably 38.0 atomic% or less, and particularly preferably 37.0 atomic% or less, relative to the total atoms of the protective film of the present invention. The content of F is preferably 35.0 atomic% or more, more preferably 36.0 atomic% or more, even more preferably 37.0 atomic% or more, and particularly preferably 38.0 atomic% or more, relative to the total atoms of the protective film of the present invention. The content of F is preferably 55.0 atomic% or less, more preferably 50.0 atomic% or less, even more preferably 48.0 atomic% or less, and particularly preferably 46.0 atomic% or less, relative to the total atoms of the protective film of the present invention.

[0017] The content of each element in the protective film of the present invention is calculated from the elemental profile obtained by measuring the average composition of the protective film using Rutherford backscatter spectroscopy, as described later. More specifically, in the obtained elemental profile, the content of each element at the depth corresponding to the protective film is calculated for each depth, and the arithmetic mean of these values ​​is taken as the content of each element.

[0018] The protective film of the present invention may contain elements other than Y, O, and F. For example, the protective film of the present invention may further 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). That is, the protective film of the present invention may contain at least one element selected from the group consisting of Sc and lanthanide elements. The content of the at least one element selected from the group consisting of Sc and lanthanide elements is preferably 5.0 atomic% or less, more preferably 3.0 atomic% or less, and even more preferably 1.0 atomic% or less. The content of at least one element selected from the group consisting of Sc and lanthanide elements may be 0.0 atomic percent or more.

[0019] <Elemental Profile> The protective film of the present invention exhibits a variation rate of Y content of 5.0% or less in the elemental profile in the film thickness direction, as measured by Rutherford Backscattering Spectroscopy (RBS), at a depth of 8 to 30 nm. The measurement method using RBS and the method for calculating the variation rate will be described below.

[0020] In this specification, a high-resolution RBS (High Resolution-RBS) manufactured by Kobe Steel, Ltd. is used for RBS measurements. The measurement and analysis conditions are as follows: • Irradiation ions: He ions • Ion irradiation energy: 450 keV • Ion incidence angle: 45° relative to the normal direction of the surface of the measurement sample • Detector installation angle: 60° relative to the ion incidence direction • Sample current: 15 nA • Irradiation dose: 24 μC • In-plane rotation: None • Detector: Micro Channel Plate / Position Sensitive Detector • Analysis method: The depth profile is determined by simulation fitting. During the analysis, 4 × 10⁻¹⁶ from the surface.１ It is assumed that the content of Y, F, and O is constant below nm. • Film density conversion: The horizontal axis of the depth profile is converted to an nm scale using film density. In this invention, the film density of the outermost contaminated layer is 0.89 g / cm³. ３ Assuming this, for the part deeper than the contaminated layer, the membrane density value (where d in the formula below) is calculated for each minute thickness layer using the following formula. Ｌ Unit: g / cm ３ Use ).

[0021]

[0022] In the above formula, C Ｙ , C Ｆ , C Ｏ , and C Ｃ These represent the content ratios (atomic ratios) of Y, O, F, and C, respectively. In the above formula, the sum of the percentages of all atoms is 1. For RBS measurement, for example, a component comprising a substrate (described later) and a protective film is used as a measurement sample. Here, the measurement sample may be a used component after use in a plasma processing apparatus (described later). When using a used component as a measurement sample, the surface altered by plasma, etc., is removed by sputtering and mechanical / chemical polishing, etc., to prepare the measurement sample. The required removal amount can be determined by obtaining the relationship between the removal amount and the content of the elements contained in advance using a glow discharge emission spectrometer, etc., and selecting the amount of removal that removes the surface altered by the protective film. The measurement sample may also be cut to an appropriate size from the above component.

[0023] When performing RBS measurements, ions are incident on the protective film side of the sample to be measured. RBS allows us to obtain the composition of the sample and its compositional distribution in the film thickness direction (depth direction) from the energy distribution of the recoiled ions. In other words, RBS provides an elemental profile in the film thickness direction, where the horizontal axis is depth (unit: nm) and the vertical axis is the content of each element (unit: atomic %). The analysis conditions are as described above. In the above elemental profile, a chart is obtained for each element contained in the protective film of the present invention (e.g., Y, O, and F), where the horizontal axis is depth and the vertical axis is content. Next, the method for calculating the variation rate of Y content will be explained.

[0024] First, Y content data at a depth of 8-30 nm is extracted from the elemental profile in the film thickness direction obtained by the method described above. Furthermore, the maximum value of Y content, C, is obtained within the above depth range. Ｙｍａｘ (Unit: atomic %) and the minimum value of Y content, C Ｙｍｉｎ (Unit: atomic %) is obtained. Next, the rate of change of Y content V Ｙ This is calculated using the following formula (1). Note that V Ｙ The unit is %. (1) V Ｙ = 100 × (C Ｙｍａｘ -C Ｙｍｉｎ ) / C Ｙｍｉｎ As described above, in the protective film of the present invention, the above V Ｙ However, it is 5.0% or less. (See above V) Ｙ If the Y content is within the above range, the protective film of the present invention is considered to have excellent plasma resistance through the mechanism described above. Furthermore, if the fluctuation rate of the Y content is small as described above, the composition fluctuates less in the film thickness direction, and the fluctuation in plasma resistance during use is considered to be small. Therefore, the protective film of the present invention, with its small fluctuation rate of Y content, can also be expected to have high reliability.

[0025] The above V Ｙ The (variability of Y content) is preferably 3.0% or less, more preferably 2.0% or less, and even more preferably 1.0% or less. Ｙ It may be 0.0% or more.

[0026] V - Rate of change of Y content ＹSimilarly, the rate of change of O content V Ｏ and the rate of change of F content V Ｆ It can also be calculated. Specifically, the maximum value of the O content within the above depth range is C Ｏｍａｘ (Unit: atomic %) and the minimum value of C, which is the O content. Ｏｍｉｎ (Unit: atomic %) is obtained. Next, the rate of change of the O content V Ｏ This is calculated using the following formula (2). Note that V Ｏ The unit is %. (2) V Ｏ = 100 × (C Ｏｍａｘ -C Ｏｍｉｎ ) / C Ｏｍｉｎ The above V Ｏ It is preferable that it be 10% or less.

[0027] <X-ray diffraction pattern> The protective film of the present invention has a Y-shaped diffraction pattern in the X-ray diffraction chart obtained by performing X-ray diffraction (XRD) measurements. ５ O ４ F ７ It is preferable to observe peaks originating from the (rhombohedral crystal system). More specifically, in the X-ray diffraction chart, Y ５ O ４ F ７ It is preferable that 151 diffraction peaks are observed, and the full width at half maximum (FMAX) of the above peaks is preferably 0.1° or more at 2θ. More preferably, the full width at half maximum of the above peaks is 0.15° or more, and even more preferably 0.2° or more. Furthermore, the full width at half maximum of the above peaks is often 2.0° or less, preferably 1.0° or less, and more preferably 0.5° or less. ５ O ４ F ７ 151 diffraction peak (Y ５ O ４ F ７ The diffraction peak attributed to the (151) plane is observed at approximately 28.1° at 2θ.

[0028] Furthermore, in the X-ray diffraction chart of the protective film of the present invention, the above Y ５ O ４ F ７ It is also desirable that no peaks other than those originating from [the specified source] are observed.

[0029] In this specification, the XRD pattern of the protective film is obtained by performing a standard measurement under the following conditions using a desktop X-ray diffractometer (MiniFlex, Rigaku). The above measurement is performed using the Out-of-Plane method (focusing method). • X-ray source: CuKα rays (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

[0030] <Raman scattering spectrum> In terms of superior plasma resistance, the Raman scattering spectrum of the protective film of the present invention shows 320 cm⁻¹. －１ No peaks are visible nearby, or 320 cm －１ If a peak is observed nearby, 320 cm －１ The mid-width of the nearby peak is 35 cm. －１ It is also preferable that it be greater than or equal to the above. The above half-width refers to the full width at half maximum. In particular, in the Raman scattering spectrum of the protective film of the present invention, 320 cm⁻¹ －１ It is preferable that no peaks are observed in the vicinity. Note that the above measurement is 320 cm. －１ The vicinity refers to the 290–350 cm range in the Raman scattering spectrum. －１ This refers to the range of 320 cm. －１ The absence of a peak in the vicinity indicates that the Raman scattering spectrum is in the 290-350 cm⁻¹ range. －１ Within this range, the background region of the Raman scattering spectrum (e.g., 900–1000 cm⁻¹) －１ When the standard deviation of the measured values ​​in ) is denoted as σ, the range is 260 to 290 cm. －１ and 350-380 cm －１ This refers to the absence of measurement points where the detection intensity is 6σ or greater than the detection intensity.

[0031] Furthermore, in the Raman scattering spectrum of the protective film of the present invention, at 500 cm² －１ No peaks are visible nearby, or 500cm －１ If a peak is observed nearby, 500 cm －１ The mid-width of the nearby peak is 35 cm. －１It is also preferable that it be greater than or equal to the above. The above half-width refers to the full width at half maximum. In particular, in the Raman scattering spectrum of the protective film of the present invention, 500 cm⁻¹ －１ It is preferable that no peaks are observed in the vicinity. －１ The vicinity refers to the 470–530 cm range in the Raman scattering spectrum. －１ This refers to the range of 500 cm. －１ The absence of a peak in the vicinity indicates that the Raman scattering spectrum is in the 470-530 cm⁻¹ range. －１ Within this range, the background region of the Raman scattering spectrum (e.g., 900–1000 cm⁻¹) －１ When the standard deviation of the measured values ​​in ) is denoted as σ, the range is 440 to 470 cm. －１ and 530-560 cm －１ This refers to the absence of measurement points where the detection intensity is 6σ or greater than the detection intensity.

[0032] In this specification, the Raman scattering spectrum of the protective film of the present invention is obtained by performing Raman spectroscopy measurements using a micro-laser Raman spectrometer (LabRAM HR800, manufactured by Horiba, Ltd.) under the following conditions: • Wavelength of excitation light: 532 nm • Excitation light irradiation diameter: 2.5 μm • Excitation light output: 400 mW • Slit width: 100 μm • Grating: 600 g / mm

[0033] <Nanoindentation Hardness> The nanoindentation hardness of the protective film of the present invention is preferably 5.0 GPa or higher, more preferably 7.0 GPa or higher, even more preferably 9.0 GPa or higher, particularly preferably 10.0 GPa or higher, and most preferably 11.0 GPa or higher. Furthermore, the nanoindentation hardness of the protective film of the present invention is often 20.0 GPa or lower, preferably 15.0 GPa or lower, and more preferably 13.0 GPa or lower.

[0034] The nanoindentation hardness of the protective film of the present invention 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.

[0035] <Surface Roughness> The surface roughness of the protective film of the present invention is preferably 50.0 nm or less, more preferably 30.0 nm or less, even more preferably 20.0 nm or less, and particularly preferably 15.0 nm or less, based on the arithmetic mean height Sa. There is no particular lower limit, but the surface roughness of the protective film of the present invention is 5.0 nm or more, and may be 10.0 nm or more, based on the arithmetic mean height Sa. The surface roughness is measured in accordance with ISO 25178. Two measurements are performed, and the arithmetic mean height Sa obtained from each measurement is taken as the surface roughness of the protective film of the present invention. In this specification, the VK-X3000 (manufactured by Keyence) is used to measure the surface roughness.

[0036] <Film Thickness> The film thickness of the protective film of the present invention 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. Furthermore, the film thickness of the protective film of the present invention 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.

[0037] In this specification, the thickness of the protective film of the present invention is measured using a scanning electron microscope (SEM). More specifically, a sample is prepared in which a cross-section parallel to the normal direction of the surface of the protective film is exposed, and the thickness of the protective film is measured at five arbitrary points by observing the cross-section of the sample, and the arithmetic mean of the thicknesses at the five points is taken as the thickness of the protective film of the present invention (unit: μm).

[0038] <Porosity> The porosity of the protective film of the present invention 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 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.

[0039] 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.

[0040] [Member] The member of the present invention includes a base material and the above-described protective film (yttrium-based protective film) of the present invention. The member of the present invention will be described with reference to the drawings.

[0041] FIG. 1 is a schematic cross-sectional view showing an example of the member 1. As shown in FIG. 1, in the member 1, the protective film 2 is formed on the side of the film-forming surface 3a which is one surface of the base material 3. That is, the member 1 has the base material and the protective film 2. As the protective film 2, the above-described protective film of the present invention is applied. The aspect of the base material 3 will be described in detail later.

[0042] <Base Material> The base material is configured to support the above protective film. The material constituting the base material is appropriately selected according to the use of the member and the like. The material constituting the base material is composed of, for example, at least one selected from the group consisting of carbon (C), ceramics, and metals. Examples of the ceramics include glass (such as soda lime glass), quartz, aluminum oxide (alumina, Al ２ O ３ ), aluminum nitride (AlN), cordierite, yttrium oxide (Y ２ O ３ ), silicon carbide (SiC), Si-impregnated silicon carbide, silicon nitride (Si ３ N ４ ), sialon (Si ３ N ４ ·Al ２ O ３ ), and at least one selected from the group consisting of aluminum oxynitride (AlON). Si-impregnated silicon carbide is obtained by heating and melting Si alone and impregnating it into silicon carbide. As the metal, at least one selected from the group consisting of aluminum and alloys containing aluminum is included.

[0043] The shape of the base material is not particularly limited, and examples include a flat plate shape, a disc shape, a ring shape, a dome shape, a concave shape, and a convex shape, etc., and are appropriately selected according to the use of the member and the like. The base material may have a through hole in a part thereof, or may be chamfered. [[ID=三十二]]

[0044] 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 surface roughness of the film-forming surface of the substrate has the same surface roughness (arithmetic mean height Sa) as the protective film.

[0045] <Applications of the component> The component of the present invention can be used, for example, as a component that constitutes a plasma processing apparatus, and in particular as a component that constitutes the inner surface of a plasma processing apparatus. Examples of plasma processing apparatuses include plasma etching apparatuses, plasma chemical vapor deposition (CVD) apparatuses, plasma atomic layer deposition (ALD) apparatuses, and plasma modification apparatuses, and these apparatuses are used, for example, in the manufacture of semiconductor devices. However, the applications of the component of the present invention are not limited to the above applications.

[0046] [Method for Manufacturing the Yttrium Protective Film] The method for manufacturing the protective film of the present invention will now be described. The method for manufacturing the protective film of the present invention is not particularly limited as long as the protective film of the present invention is obtained, but for example, it is formed by vapor deposition on the film-forming surface of the substrate. As the vapor deposition method, the DPDS (Digitally Processed DC Sputtering) method is preferred in that it is easier to obtain the protective film of the present invention. The DPDS method refers to a method in which a process of forming a metal thin film by DC sputtering and a process of bringing the formed metal thin film into contact with a reactive gas are carried out alternately. According to the DPDS method, it is easy to obtain the protective film of the present invention in which the variation rate of Y content is within a predetermined range. The following describes a method for forming a protective film on the film-forming surface of a substrate using the DPDS method.

[0047] When forming a protective film using the DPDS method, it is preferable to alternately repeat the formation of a metal thin film (metallic yttrium film) and the oxidation and fluorination of the formed metal thin film. The formation of the metal thin film and the oxidation and fluorination of the metal thin film may be carried out using separate chambers (not shown).

[0048] Specifically, for example, first, a substrate is placed in a first chamber in an inert gas (e.g., argon gas) atmosphere. Then, using a sputtering target made of metallic yttrium, a metal thin film is formed on the film-forming surface of the substrate. The thickness of the metal thin film in one formation is preferably sub-nm (less than 1.0 nm).

[0049] Next, the substrate with the formed metal thin film is transferred into a second chamber in a mixed gas atmosphere of an inert gas, oxygen gas, and a fluorine-containing compound gas, and the metal thin film is oxidized and fluorinated. In the second chamber, it is preferable that the mixed gas is in a plasma state. When the mixed gas is in a plasma state, it is easier to form the protective film of the present invention. As the fluorine-containing compound gas, F ２ gas, CF ４ gas, C ２ F ６ gas, NF ３ gas, etc. can be mentioned, and NF ３ gas is preferable.

[0050] In the above mixed gas, the ratio of the supply amount of the inert gas to the supply amount of the oxygen gas (inert gas supply amount / oxygen gas supply amount) is preferably 0.30 or more, preferably 0.40 or more, and more preferably 0.50 or more. The ratio (inert gas supply amount / oxygen gas supply amount) is preferably 1.50 or less, more preferably 1.20 or less, and even more preferably 1.00 or less. Also, in the above mixed gas, the ratio of the supply amount of the oxygen gas to the supply amount of the fluorine-containing compound gas (oxygen gas supply amount / fluorine-containing compound gas supply amount) is preferably 1.0 or more, preferably 2.0 or more, and more preferably 3.0 or more. The ratio (oxygen gas supply amount / fluorine-containing compound gas supply amount) is preferably 20.0 or less, more preferably 15.0 or less, and even more preferably 10.0 or less. Note that by adjusting the above ratios (inert gas supply amount / oxygen gas supply amount, and oxygen gas supply amount / fluorine-containing compound gas supply amount), the contents of O and F in the obtained protective film can be adjusted.

[0051] When forming, oxidizing, and fluorinating a metal thin film, for example, while controlling the pressure in the chamber to 0.05 to 0.4 Pa (preferably 0.08 to 0.3 Pa, more preferably 0.1 to 0.28 Pa), an electric field is applied between the anode and cathode in the first chamber to generate plasma and perform sputtering. The formation, oxidation, and fluorination of the metal thin film are repeated alternately, and the oxidized and fluorinated metal thin films are stacked to a desired thickness to obtain the protective film of the present invention containing Y, O, and F. According to the above procedure, the protective film of the present invention is obtained in which Y is sufficiently oxidized and fluorinated, and the variation rate of the Y content is within a predetermined range.

[0052] The present invention will be described in more detail below based on the following examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the following examples. Examples 1 to 4 are examples, and Example 5 is a comparative example.

[0053] [Example 1] <Manufacturing of component> A protective film containing Y, O, and F 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, plate thickness: 2 mm) using a sputtering apparatus (RAS-1100BII, manufactured by Synchron Corporation) by the DPDS method described above, thereby obtaining the component of Example 1. The thickness of the protective film was 10 μm. Details of the film formation conditions are described in Table 1 below. The protective film of the obtained component of Example 1 was analyzed for the items listed in the table below (composition, variation rate of Y content, Y ５ O ４ F ７ The peak full width at half maximum (FWHM) of the (151) plane, the presence or absence of a peak in the Raman scattering spectrum and its FWHM, the nanoindentation hardness, and the surface roughness were measured using the method described above.

[0054] <Plasma Resistance (Etching Amount)> The plasma resistance was evaluated by performing plasma etching on the protective film of the obtained component. More specifically, first, the component was cut 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 film thickness of 100 μm to obtain a test sample. Plasma etching was performed on the above test sample using RIE-101iPH (manufactured by Samco). Specifically, the above test sample was placed on the stage of the plasma etching apparatus and SF ６ / O ２ Etching was performed by generating an inductively coupled plasma (ICP) using a mixed gas of / Ar (mixing ratio: 4 / 1 / 5). The plasma etching conditions were as follows: Plasma: Inductively coupled plasma, Power: 550W, Pressure: 3Pa, Etching time: 60 minutes. After plasma etching, the polyimide tape of the test sample was peeled off, and the height difference between the surface covered by the polyimide tape and the exposed surface was measured using a contact surface shape measuring instrument (dektak-XT, ULVAC, Inc.). Measurements were performed at three points, and the average of the three measurements was taken as the etching amount (unit: nm). The results are shown in the table below. A smaller etching amount indicates better plasma resistance.

[0055] Also, CF ４ / O ２ Plasma etching was performed in the same manner as described above, except that a mixed gas of / Ar (mixing ratio: 4 / 1 / 5) was used, and the apparatus and conditions were modified as follows to irradiate with capacitively coupled plasma (CCP) for plasma etching. The results of measuring the etching amount are also shown in the table below. EXAM (manufactured by Shinko Seiki Co., Ltd.) was used as the CCP. Plasma: Capacitively coupled plasma Output: 550W Pressure: 3Pa Etching time: 60 minutes

[0056] <Examples 2 to 4> Except for changing the film deposition conditions as shown in the table below, the components of Examples 2 to 4 were obtained in the same manner as in Example 1, and measurements and plasma resistance evaluations were performed in the same manner as in Example 1. The results are shown in the table below.

[0057] <Example 5> A protective film was formed on the same substrate as in Example 1 by ion-assisted deposition (IAD). Y was used as the deposition source in separate crucibles. ２ O ３ and YF ３ Y was used to form the protective film described above. ２ O ３ A crucible containing YF ３ Each crucible containing Y is heated by irradiating it with an electron beam. ２ O ３ and YF ３ The solution was evaporated, and the deposition was carried out while rotating the substrate. YF ３ Evaporation rate (R_YF ３ ) for Y ２ O ３ Evaporation rate (R_Y ２ O ３ ) ratio (R_Y ２ O ３ / R_YF ３ The electron beam irradiation dose was adjusted so that it was 4 / 7. Also, YF ３ and Y ２ O ３ The total deposition rate was set to 12 nm / min. ２ O ３ and YF ３ During the deposition process, an oxygen ion beam was irradiated onto the substrate from an ion source. The distance between the ion source and the substrate was 1100 mm, the ion beam current was 2000 mA, and the ion beam current density was 100 μA / cm². ２ The pressure inside the chamber during the above deposition was 6.0 × 10⁻⁶. ―２ The value was Pa. Following the procedure described above, the component of Example 5 was obtained. The obtained component of Example 5 was subjected to measurement and plasma resistance evaluation in the same manner as in Example 1.

[0058] [Results] Table 1 shows the film deposition conditions for the protective film, the measurement results of the protective film, and the evaluation results of plasma resistance for each example. Note that in Table 1, "XRD" is replaced with "Y ５ O ４ F ７ In the "Peak Presence / Absence" column, enter the above Y ５ O ４ F ７ This indicates whether or not a peak was observed on the (151) plane. Also, in the "Peak Half Max Width" column of "XRD", Y ５ O ４ F ７ This shows the peak half-width of the (151) surface.

[0059]

[0060] From the results shown in Table 1, it was confirmed that the members (protective films) of Examples 1 to 4, in which the fluctuation rate of Y content is within a predetermined range, have superior plasma resistance compared to the member (protective film) of Example 5, in which the fluctuation rate of Y content is not within a predetermined range. From a comparison between Examples 1 and 2 and Examples 3 and 4, it was found that when the nanoindentation hardness is 10.0 GPa or higher (more preferably 11.0 GPa or higher), CF ４ / O ２ It was confirmed that the material exhibits excellent plasma resistance when etched with a mixed gas of / Ar. Furthermore, when the porosity of the materials (protective films) of Examples 2 to 4 was measured according to the method described above, it was found to be less than 0.10 volume%.

[0061] Furthermore, the entire contents of the specification, claims, drawings, and abstract of Japanese Patent Application No. 2025-011328, filed on January 27, 2025, are incorporated herein by reference as disclosure of the present invention.

[0062] 1: Component 2: Protective film 3: Substrate 3a: Film-forming surface

Claims

1. A yttrium-based protective film containing yttrium, oxygen, and fluorine, wherein the variation rate of yttrium content in the elemental profile in the film thickness direction, as measured by Rutherford backscatter spectroscopy, is 5.0% or less at a depth of 8 to 30 nm.

2. In the X-ray diffraction chart obtained by performing X-ray diffraction measurements, Y ５ O ４ F ７ The yttrium protective film according to claim 1, wherein the full width at half maximum of the 151 diffraction peak is 0.2° or more at 2θ.

3. In the Raman scattering spectrum, at 320 cm⁻¹ －１ No peaks are visible nearby, or 320 cm －１ If a peak is observed nearby, 320 cm －１ The mid-width of the nearby peak is 35 cm. －１ The yttrium protective film according to claim 1 or 2.

4. In the Raman scattering spectrum, is there no peak near 500 cm －１ -1, or if there is a peak near 500 cm －１ -1, then when the full width at half maximum of the peak near 500 cm －１ -1 is 35 cm －１ -1 or more, the yttrium-based protective film according to claim 1 or 2.

5. The yttrium protective film according to claim 1 or 2, wherein the yttrium content is 15.0 to 35.0 atomic percent relative to the total atoms of the yttrium protective film.

6. The yttrium protective film according to claim 1 or 2, wherein the oxygen content is 30.0 to 40.0 atomic percent relative to the total atoms of the yttrium protective film.

7. The yttrium protective film according to claim 1 or 2, wherein the fluorine content is 35.0 to 55.0 atomic percent relative to the total atoms of the yttrium protective film.

8. The yttrium protective film according to claim 1 or 2, 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.

9. The yttrium protective film according to claim 1 or 2, wherein the nanoindentation hardness is 5.0 GPa or higher.

10. The yttrium protective film according to claim 1 or 2, wherein the surface roughness is 50.00 nm or less in arithmetic mean height Sa.

11. The yttrium protective film according to claim 1 or 2, wherein the film thickness is 1.0 μm or more and 100.0 μm or less.

12. A component comprising a base material and a yttrium protective film according to claim 1 or 2.

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

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