JP6772994B2 - Structure - Google Patents

Description

Aspects of the present invention generally relate to structures.

As a member used in a plasma irradiation environment such as a semiconductor manufacturing apparatus, a member having a highly plasma resistant film formed on its surface is used. For the coating film, for example, oxides such as alumina (Al ₂ O ₃ ) and yttria (Y ₂ O ₃ ), or nitrides such as aluminum nitride (AlN) are used.

On the other hand, in oxide-based ceramics, the volume of the film expands due to fluoride due to the reaction with CF-based gas, cracks and the like occur, and as a result, it leads to the generation of particles. Proposals have been made to use fluoride-based ceramics such as yttrium (YF ₃ ) (Patent Document 1).

In addition, YF ₃ has high resistance to F-based plasma, but its resistance to Cl-based plasma is insufficient, or there is doubt about the chemical stability of fluoride, and yttrium oxyfluoride (YOF) It has also been proposed to use a coating or a sintered body (Patent Documents 2 and 3).

So far, YF ₃ and YOF have been studied with sprayed membranes and sintered bodies. However, the sprayed film and the sintered body may have insufficient plasma resistance, and it is required to further improve the plasma resistance.
For example, it has been studied to form a thermal sprayed film using a rare earth element oxyfluoride as a raw material (Patent Document 4). However, in thermal spraying, oxidation occurs due to oxygen in the atmosphere during heating. Therefore, Y ₂ O ₃ may be mixed in the obtained sprayed film, and it may be difficult to control the composition. In addition, the sprayed film still has a problem in density. Further, in plasma etching, if a chamber coated with YF ₃ by thermal spraying or the like is used, there is a problem that the etching rate drifts and is not stable (Patent Document 5). Further, a method of forming a film containing Y ₂ O ₃ and then fluorinating the film by annealing such as plasma treatment has also been studied (Patent Document 6). However, in this method, since the fluorination treatment is applied to the membrane containing Y ₂ O _3, which is once formed, the volume of the film is changed peeled from the substrate by fluoride, or film cracked in the like May cause problems. In addition, it may be difficult to control the composition of the entire membrane. Further, in thermal spraying and sintered bodies, F ₂ gas is released due to thermal decomposition of fluoride raw material fine particles during heating, which poses a safety problem.

On the other hand, Patent Document 7 discloses that Y ₂ O ₃ can form a plasma-resistant structure at room temperature by an aerosol deposition method. However, the aerosol deposition method using yttrium oxyfluoride has not been sufficiently studied.

Japanese Unexamined Patent Publication No. 2013-140950 Japanese Unexamined Patent Publication No. 2014-09361 Japanese Unexamined Patent Publication No. 2016-098143 Japanese Patent No. 5927656 U.S. Patent Application Publication No. 2015/0126036 U.S. Patent Application Publication No. 2016/273095 Japanese Unexamined Patent Publication No. 2005-217351

In structures containing yttrium oxyfluoride, plasma resistance may vary.
The present invention has been made based on the recognition of such a problem, and an object of the present invention is to provide a structure capable of enhancing plasma resistance.

The first invention is a structure containing a polycrystal of yttriumoxyfluoride having a rhombic crystal structure as a main component and having an average crystallite size of less than 100 nanometers in the polycrystal. The peak intensity of the rhombic crystal detected near the diffraction angle 2θ = 13.8 ° by line diffraction is r1, and the peak intensity of the rhombic crystal detected near the diffraction angle 2θ = 36.1 ° is r2. When γ1 is γ1 (%) = r2 / r1 × 100, the ratio γ1 is 0% or more and less than 100%.
The second invention is a structure in which the ratio γ1 is less than 80% in the first invention.

The inventors of the present application have found that there is a correlation between a predetermined peak intensity ratio (ratio γ1) of rhombohedral yttrium oxyfluoride and plasma resistance performance. It has been found that when the ratio γ1 is 100% or more, the plasma resistance performance becomes low. By setting the ratio γ1 to 0% or more and less than 100%, preferably less than 80%, it is possible to exhibit practically excellent plasma resistance performance.

A third aspect of the invention is that in the first or second invention, the structure does not contain ittrium oxyfluoride having an orthorhombic crystal structure, or is an ittrium oxyfluoride having an orthorhombic crystal structure. When the peak intensity of the orthorhombic crystal detected near the diffraction angle 2θ = 16.1 ° is о and the ratio of the orthorhombic crystal to the rhombic crystal is γ2 (%) = о / r1 × 100. In addition, the ratio γ2 is a structure of 0% or more and less than 100%.
The inventors of the present application have found that there is a correlation between the ratio of the compound or the crystal phase in the structure (ratio γ2) and the plasma resistance. It has been found that when the ratio γ2 is 100% or more, the plasma resistance is low. Plasma resistance can be enhanced by setting the ratio γ2 to 0% or more and less than 100%.

In the fourth invention, in any one of the first to third inventions, the yttrium oxyfluoride having a rhombohedral crystal structure is a structure that is YOF.
A fifth invention is a structure in which the yttrium oxyfluoride having an orthorhombic crystal structure is a YOF of 1: 1: 2 in the third invention.
According to these structures, plasma resistance can be enhanced.

The sixth invention is a structure in which the ratio γ2 is 85% or less in the third invention.
The seventh invention is a structure in which the ratio γ2 is 70% or less in the third invention.
The eighth invention is a structure in which the ratio γ2 is 30% or less in the third invention.
According to these structures, plasma resistance can be further enhanced.

The ninth invention is a structure in which the average crystallite size is less than 50 nanometers in any one of the first to eighth inventions.
The tenth invention is a structure in which the average crystallite size is less than 30 nanometers in any one of the first to eighth inventions.
The eleventh invention is a structure in which the average crystallite size is less than 20 nanometers in any one of the first to eighth inventions.
According to these structures, the small average crystallite size makes it possible to reduce the size of particles generated from the structure by plasma.

The twelfth invention is the ε with respect to the r1 in any one of the first to eleventh inventions, where ε is the peak intensity detected at a diffraction angle of 2θ = 29.1 ° by X-ray diffraction. A structure in which at least one of the ratio of ε and the ratio of ε to r2 is less than 1%.
According to this structure, since Y ₂ O ₃ contained in the structure is very small, fluorine due to CF-based plasma is suppressed, and plasma resistance can be further improved.

The thirteenth invention is the ε with respect to the r1 in any one of the first to eleventh inventions, where ε is the peak intensity detected in the vicinity of the diffraction angle 2θ = 29.1 ° by X-ray diffraction. At least one of the ratio of the above and the ratio of the ε to the r2 is 0%.
According to this structure, since Y ₂ O ₃ is substantially not contained, fluorine due to CF-based plasma is suppressed, and plasma resistance can be further improved.

According to the aspect of the present invention, there is provided a structure containing yttrium oxyfluoride having a rhombohedral crystal structure and capable of enhancing plasma resistance.

It is sectional drawing which illustrates the member which has the structure which concerns on embodiment. It is a table which illustrates the raw material of a structure. It is a table which exemplifies the sample of a structure. 4 (a) and 4 (b) are graphs showing X-ray diffraction in a sample of the structure. It is a graph which shows the X-ray diffraction in the sample of a structure. It is sectional drawing which illustrates the member which has another structure which concerns on embodiment. It is a photographic figure which illustrates the structure which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, similar components are designated by the same reference numerals and detailed description thereof will be omitted as appropriate.
FIG. 1 is a cross-sectional view illustrating a member having a structure according to an embodiment.
As shown in FIG. 1, the member 10 is a composite structure having, for example, a base material 15 and a structure 20.
The member 10 is, for example, a member for a semiconductor manufacturing apparatus having a chamber, and is provided inside the chamber. Since gas is introduced into the chamber and plasma is generated, the member 10 is required to have plasma resistance. The member 10 (structure 20) may be used in a place other than the inside of the chamber, and the semiconductor manufacturing apparatus is an arbitrary semiconductor manufacturing apparatus (semiconductor processing apparatus) that performs processing such as annealing, etching, sputtering, and CVD. including. Further, the member 10 (structure 20) may be used for a member other than the semiconductor manufacturing apparatus.

The base material 15 contains, for example, alumina. However, the material of the base material 15 is not limited to ceramics such as alumina, and may be quartz, alumite, metal, glass, or the like. In this example, the member 10 having the base material 15 and the structure 20 is described. The embodiment in which the base material 15 is not provided and only the structure 20 is provided is also included in the embodiment. The arithmetic mean roughness Ra (JISB0601: 2001) of the surface of the base material 15 (the surface on which the structure 20 is formed) is, for example, less than 5 micrometers (μm), preferably less than 1 μm, and more preferably 0.5 μm. Is less than.

The structure 20 contains a polycrystal of yttrium oxyfluoride having a rhombohedral crystal structure. The main component of the structure 20 is a polycrystal of yttrium oxyfluoride (YOF) having a rhombohedral crystal structure.

In the present specification, the main component of the structure is relatively larger than the other compounds contained in the structure 20 by quantitative or semi-quantitative analysis by X-ray diffraction (XRD) of the structure. Refers to the contained compound. For example, the main component is a compound contained most in the structure, and the proportion of the main component in the structure is larger than 50% by volume or mass ratio. The proportion of the main component is more preferably larger than 70% and preferably larger than 90%. The proportion of the main component may be 100%.

The yttrium oxyfluoride is a compound of yttrium (Y), oxygen (O) and fluorine (F). Examples of yttrium oxyfluoride include 1: 1: 1 YOF (molar ratio Y: O: F = 1: 1: 1) and 1: 1: 2 YOF (molar ratio Y: O: F =). 1: 1: 2) can be mentioned. In the specification of the present application, the range of Y: O: F = 1: 1: 2 is not limited to the composition in which Y: O: F is exactly 1: 1: 2, and the molar ratio of fluorine to yttrium (F). / Y) may contain a composition greater than 1 and less than 3. For example, as yttrium oxyfluoride of Y: O: F = 1: 1: 2, Y ₅ O ₄ F ₇ (molar ratio Y: O: F = 5: 4: 7), Y ₆ O ₅ F ₈ (molar ratio Y: O: F = 5: 4: 7) Mole ratio is Y: O: F = 6: 5: 8), Y ₇ O ₆ F ₉ (Mole ratio is Y: O: F = 7: 6: 9), Y ₁₇ O ₁₄ F ₂₃ (Mole ratio is Y) : O: F = 17: 14: 23) and the like. Further, in the specification of the present application, the term "YOF" means Y: O: F = 1: 1: 1, and the term "1: 1: 2 YOF" means the above-mentioned Y: O. : F = 1: 1: 2. The range of yttrium oxyfluoride may include compositions other than the above.

In the example of FIG. 1, the structure 20 has a single-layer structure, but the structure formed on the base material 15 may have a multi-layer structure (see FIG. 6). For example, the substrate 15, the layer 21 corresponding to the structure 20 in FIG. 1, another layer 22 (e.g., a layer comprising Y ₂ O ₃₎ may be provided between the. The layer 21 corresponding to the structure 20 forms the surface of the multi-layered structure 20a.

The structure 20 is formed of a raw material containing, for example, yttrium oxyfluoride. This raw material is produced, for example, by fluorinated yttria. According to this manufacturing process, the raw material is roughly classified into two types, one having a high oxygen content and the other having a low oxygen content. Raw materials with high oxygen content include, for example, YOF, 1: 1: 2 YOF (eg, Y ₅ O ₄ F ₇ , Y ₇ O ₆ F _9, etc.). The raw material having a high oxygen content may contain only YOF. Further, the raw material having a low oxygen content contains, for example, YF ₃ in addition to Y ₅ O ₄ F ₇ , Y ₇ O ₆ F _{9, and the} like, and does not contain YOF. If sufficient fluoride treatment is performed, the raw material will contain only YF ₃ and may not contain yttrium oxyfluoride. In this embodiment, the structure contains rhombohedral yttrium oxyfluoride. When the raw material or structure contains rhombohedral yttrium oxyfluoride, a peak is detected in at least one of the diffraction angle 2θ = 13.8 ° and the diffraction angle 2θ = 36.1 ° in X-ray diffraction. It shall mean that.

In structures used in semiconductor manufacturing equipment and the like, YF ₃ , Y ₅ O ₄ F ₇ , Y ₇ O ₆ F _{9, and the} like may be oxidized over time and changed to YOF. It is also reported that YOF is superior in corrosion resistance to other compositions (Patent Document 3).

The inventors of the present application have a correlation between the plasma resistance and the crystal structure of the structure in a structure containing yttrium oxyfluoride as a main component, and enhance the plasma resistance by controlling the crystal structure. I found that I could do it. The plasma resistance can be improved by controlling the crystal structure of yttrium oxyfluoride contained in the structure.

Specifically, the crystal structure of the structure 20 according to the embodiment is as follows.
The structure 20 contains a polycrystal of yttrium oxyfluoride having a rhombohedral crystal structure. Further, in the X-ray diffraction of the structure 20, the ratio γ1 regarding the peak intensity of the rhombohedral crystal is 0% or more and less than 100%, preferably less than 80%.

Here, the ratio γ1 is calculated by the following method.
X-ray diffraction is performed on the structure 20 containing yttrium oxyfluoride by θ-2θ scan. Let r1 be the peak intensity of the rhombohedral crystal detected at a diffraction angle of 2θ = 13.8 ° by X-ray diffraction on the structure 20. Let r2 be the peak intensity of the rhombohedral crystal detected near the diffraction angle 2θ = 36.1 ° by X-ray diffraction on the structure 20. At this time, γ1 (%) = r2 / r1 × 100. For example, the ratio γ1 represents the degree of orientation of yttrium oxyfluoride in rhombohedral crystals.

It is considered that the peak near the diffraction angle 2θ = 13.8 ° and the peak near the diffraction angle 2θ = 36.1 ° are caused by, for example, the YOF of the rhombohedral crystal.
Further, the diffraction angle 2θ = 13.8 ° is, for example, about 13.8 ± 0.4 ° (13.4 ° or more and 14.2 ° or less), and the diffraction angle 2θ = 36.1 ° or the like. For example, it is about 36.1 ° ± 0.4 ° (35.7 ° or more and 36.5 ° or less).

Further, the structure 20 contains yttrium oxyfluoride having a rhombic crystal structure and does not contain yttrium oxyfluoride having an orthorhombic crystal structure.
Alternatively, the structure 20 contains yttrium oxyfluoride having a rhombic crystal structure and yttrium oxyfluoride having an orthorhombic crystal structure, and the ratio γ2 of the orthorhombic crystal to the orthorhombic crystal is 0%. More than 100%.

Here, the ratio γ2 is calculated by the following method.
X-ray diffraction (XRD) is performed on the structure 20 containing yttrium oxyfluoride by θ-2θ scan. Let r1 be the peak intensity of the rhombohedral crystal detected by X-ray diffraction at a diffraction angle of 2θ = 13.8 °. Let о be the peak intensity of orthorhombic crystals detected at a diffraction angle of 2θ = 16.1 ° by X-ray diffraction. At this time, γ2 (%) = о / r1 × 100.

The peak near the diffraction angle 2θ = 16.1 ° is the orthorhombic 1: 1: 2 YOF (for example, at least one of the orthorhombic Y ₅ O ₄ F ₇ or Y ₇ O ₆ F ₉ ). It is thought that this is due to.
Further, the diffraction angle around 2θ = 16.1 ° is, for example, about 16.1 ± 0.4 ° (15.7 ° or more and 16.5 ° or less).

The ratio of orthorhombic crystals to rhombohedral crystals γ2 is preferably 85% or less, more preferably 70% or less, still more preferably 30% or less, and most preferably 0%. In the present specification, γ2 = 0% means that it is below the lower limit of detection in measurement, and is synonymous with substantially not containing yttrium oxyfluoride having an orthorhombic crystal structure.

In the yttrium oxyfluoride polycrystal contained in the structure, the average crystallite size is, for example, less than 100 nm, preferably less than 50 nm, more preferably less than 30 nm, and most preferably less than 20 nm. Since the average crystallite size is small, the particles generated by the plasma can be made small.

X-ray diffraction can be used to measure the crystallite size.
As the average crystallite size, the crystallite size can be calculated by the following Scheller's formula.
D = Kλ / (βcosθ)
Here, D is the crystallite size, β is the peak half width (radian (rad)), θ is the Bragg angle (rad), and λ is the wavelength of the X-ray used for the measurement.
In Scheller's equation, β is calculated by β = (βobs-βstd). βobs is the half width of the X-ray diffraction peak of the measurement sample, and βstd is the half width of the X-ray diffraction peak of the standard sample. K is a Scheller constant.
In yttrium oxyfluoride, the X-ray diffraction peaks that can be used to calculate the crystallite size are, for example, peaks caused by the mirror surface (006) near the diffraction angle 2θ = 28 °, and the diffraction angle 2θ = 29 °. A peak caused by the mirror surface (012) in the vicinity, a peak caused by the mirror surface (018) near the diffraction angle 2θ = 47 °, a peak caused by the mirror surface (110) near the diffraction angle 2θ = 48 °, and the like. ..
The crystallite size may be calculated from an image such as TEM observation. For example, as the average crystallite size, the average value of the diameters corresponding to the circles of the crystallites can be used.

The distance between crystallites adjacent to each other is preferably 0 nm or more and less than 10 nm. The distance between adjacent crystallites is the distance between the crystallites that are closest to each other, and does not include voids composed of a plurality of crystallites. The distance between the crystallites can be determined from an image obtained by observation using a transmission electron microscope (TEM). In addition, FIG. 7 shows a TEM image of observing an example of the structure 20 according to the embodiment. The structure 20 contains a plurality of crystallites 20c (crystal particles).

Further, for example, the structure 20 substantially does not contain Y ₂ O ₃ . Let ε be the peak intensity caused by Y ₂ O ₃ detected near the diffraction angle 2θ = 29.1 ° when X-ray diffraction is performed on the structure 20 by θ-2θ scan. At this time, at least one of the ratio of ε to r1 (ε / r1) and the ratio of ε to r2 (ε / r2) is less than 1%, more preferably 0%. Structure 20 does not include Y ₂ O _3, or by Y ₂ O ₃ contained in the structure 20 is very small, fluoride with CF-based plasma is suppressed, it is possible to further improve the plasma resistance .. The vicinity of 2θ = 29.1 ° is, for example, about 29.1 ± 0.4 ° (28.7 ° or more and 29.5 ° or less).

The structure 20 according to the embodiment can be formed, for example, by arranging fine particles such as a brittle material on the surface of the base material 15 and applying a mechanical impact force to the fine particles. Here, as a method of "applying mechanical impact force", for example, a compressive force generated by a shock wave generated at the time of an explosion is used by using a high-hardness brush or roller that rotates at high speed or a piston that moves up and down at high speed. , Or an ultrasonic wave is applied, or a combination thereof can be mentioned.

Further, it is also preferable that the structure 20 according to the embodiment is formed by, for example, an aerosol deposition method.
In the "aerosol deposition method", "aerosol" in which fine particles containing brittle materials are dispersed in a gas is injected from a nozzle toward a base material, and the fine particles collide with a base material such as metal, glass, ceramics or plastic. The impact of this collision causes the brittle material fine particles to be deformed or crushed to join them, and a structure containing the constituent materials of the fine particles (for example, a layered structure or a film-like structure) is directly formed on the base material. It is a way to make it. According to this method, a structure can be formed at room temperature without requiring a heating means or a cooling means, and a structure having mechanical strength equal to or higher than that of a sintered body can be obtained. Further, by controlling the conditions for colliding the fine particles and the shape and composition of the fine particles, it is possible to change the density, mechanical strength, electrical characteristics, etc. of the structure in various ways.

In the specification of the present application, "polycrystal" means a structure in which crystal particles are bonded and accumulated. The diameter of the crystal particles is, for example, 5 nanometers (nm) or more.

Further, in the specification of the present application, when the primary particles are dense particles, the average particle size identified by particle size distribution measurement, scanning electron microscope, etc. is 5 micrometers (μm) or less. To say. When the primary particles are porous particles that are easily crushed by impact, they have an average particle size of 50 μm or less.

Further, in the present specification, the "aerosol" refers to a solid-gas mixed phase in which the above-mentioned fine particles are dispersed in a gas (carrier gas) such as helium, nitrogen, argon, oxygen, dry air, and a mixed gas containing these. It refers to a state in which fine particles are substantially dispersed alone, although some "aggregates" may be contained. The gas pressure and temperature of the aerosol are arbitrary, but the concentration of fine particles in the gas is 0.0003 mL / L at the time of injection from the discharge port when the gas pressure is converted to 1 atm and the temperature is converted to 20 degrees Celsius. It is desirable for the formation of the structure to be in the range of ~ 5 mL / L.

The aerosol deposition process is usually carried out at room temperature and is characterized in that the structure can be formed at a temperature sufficiently lower than the melting point of the fine particle material, that is, at 100 degrees Celsius or less.
In the specification of the present application, "normal temperature" means a room temperature environment of 0 to 100 ° C., which is a temperature significantly lower than the sintering temperature of ceramics.
As used herein, the term "powder" refers to a state in which the above-mentioned fine particles are naturally aggregated.

Hereinafter, studies by the inventors of the present application will be described.
FIG. 2 is a table illustrating the raw materials of the structure.
In this study, eight kinds of powders of raw materials F1 to F8 shown in FIG. 2 are used. These raw materials are powders of yttrium oxyfluoride and contain at least one of YOF and 1: 1: 2 YOF (eg, Y ₅ O ₄ F ₇ , Y ₇ O ₆ F _9, etc.). Also, each raw material is substantially free of YF ₃ and Y ₂ O ₃ .

Note that the fact that YF ₃ is not substantially contained means that in X-ray diffraction, the peak intensity due to YF ₃ at a diffraction angle of 2θ = 24.3 ° or 25.7 ° is a diffraction angle of 2θ = 13.8. It means that it is less than 1% of the peak intensity caused by YOF near ° or 36.1 °. Alternatively, the fact that YF ₃ is not substantially contained means that in X-ray diffraction, the peak intensity due to YF ₃ at a diffraction angle of 2θ = 24.3 ° or 25.7 ° is a diffraction angle of 2θ = 32.8. It means that it is less than 1% of the peak intensity due to the 1: 1: 2 YOF near °. The vicinity of 2θ = 24.3 ° is, for example, about 24.3 ± 0.4 ° (23.9 ° or more and 24.7 ° or less). The vicinity of 2θ = 25.7 ° is, for example, about 25.7 ± 0.4 ° (25.3 ° or more and 26.1 ° or less). The vicinity of 2θ = 32.8 ° is, for example, about 32.8 ° ± 0.4 ° (32.4 ° or more and 33.2 ° or less).
Further, the fact that Y ₂ O ₃ is not substantially contained means that in X-ray diffraction, the peak intensity due to Y ₂ O ₃ near the diffraction angle 2θ = 29.1 ° is around the diffraction angle 2θ = 13.8 °. Or, it means that it is less than 1% of the peak intensity caused by YOF near 36.1 °. Alternatively, the fact that Y ₂ O ₃ is not substantially contained means that in X-ray diffraction, the peak intensity due to Y ₂ O ₃ near the diffraction angle 2θ = 29.1 ° is around the diffraction angle 2θ = 32.8 °. It means that it is less than 1% of the peak intensity caused by YOF of 1: 1: 2.

The raw materials F1 to F8 are different in particle size from each other as shown in FIG. 2 having a median diameter (D50 (μm)). The median diameter is 50% of the cumulative distribution of the particle size of each raw material. As the diameter of each particle, the diameter obtained by circular approximation is used.
Samples of a plurality of structures (layered structures) were prepared by changing the combination of these raw materials and the film forming conditions (type and flow rate of carrier gas), and the plasma resistance was evaluated. In this example, the aerosol deposition method is used to prepare the sample.

FIG. 3 is a table illustrating a sample of the structure.
As shown in FIG. 3, nitrogen (N ₂ ) or helium (He) is used as the carrier gas. The aerosol is obtained by mixing the carrier gas and the raw material powder (raw material fine particles) in the aerosol generator. The obtained aerosol is ejected from a nozzle connected to the aerosol generator by a pressure difference toward a substrate arranged inside the film forming chamber. At this time, the air in the film forming chamber is exhausted to the outside by a vacuum pump. The flow rate of the carrier gas is 5 (liters / minute: L / min) to 10 (L / min) in the case of nitrogen, and 3 (L / min) to 5 (L / min) in the case of helium.

Each of the structures of Samples 1 to 10 mainly contained a polycrystal of yttrium oxyfluoride, and the average crystallite size in the polycrystal was less than 100 nm.

X-ray diffraction was used to measure the crystallite size.
As the XRD apparatus, "X'PertPRO / PANalytical" was used. A tube voltage of 45 kV, a tube current of 40 mA, a Step Size of 0.033 °, and a Time per Step of 336 seconds or more were used.
As the average crystallite size, the crystallite size was calculated by the above-mentioned Scheller's formula. 0.94 was used as the value of K in Scheller's equation.

X-ray diffraction was used to measure the main components of the crystal phase of the yttrium oxyfluoride. As the XRD apparatus, "X'PertPRO / PANalytical" was used. X-ray Cu-Kα (wavelength 1.5418 Å), tube voltage 45 kV, tube current 40 mA, Step Size 0.033 °, Time per Step 100 seconds or more were used. The XRD analysis software "High Score Plus / PANalytical" was used to calculate the principal components. It was calculated by the relative intensity ratio obtained when the peak search was performed on the diffraction peak using the quasi-quantitative value (RIR = Reference Intelligence Ratio) described on the ICDD card. In the case of a laminated structure, in the measurement of the main component of the yttrium oxyfluoride, it is desirable to use the measurement result in the depth region of less than 1 μm from the outermost surface by the thin film XRD.

In addition, the crystal structure of yttrium oxyfluoride was evaluated using X-ray diffraction. As the XRD apparatus, "X'PertPRO / PANalytical" was used. X-ray Cu-Kα (wavelength 1.5418 Å), tube voltage 45 kV, tube current 40 mA, Step Size 0.033 ° were used. In order to improve the measurement accuracy, it is preferable that the Time per Step is 700 seconds or longer.

The ratio γ1 of the peak intensity of the rhombohedral crystal in the yttrium oxyfluoride is the peak intensity (r1) caused by the rhombohedral crystal of the yttrium oxyfluoride near the diffraction angle 2θ = 13.8 ° and the diffraction angle 2θ = 36. . Calculated by r2 / r1 × 100 (%) using the peak intensity (r2) due to the rhombohedral crystals of yttrium oxyfluoride near 1 °.

As described above, X-ray diffraction was used for the measurement of the ratio γ2 of the orthorhombic crystal to the rhombohedral crystal in the yttrium oxyfluoride. As the XRD apparatus, "X'PertPRO / PANalytical" was used. X-ray Cu-Kα (wavelength 1.5418 Å), tube voltage 45 kV, tube current 40 mA, Step Size 0.033 ° were used. In order to improve the measurement accuracy, it is preferable that the Time per Step is 700 seconds or longer.

The ratio of orthorhombic crystals to rhombohedral crystals γ2 is the peak intensity (r1) caused by the mirror surface (003) of rhombohedral crystals including YOF and the like at a diffraction angle of 2θ = 13.8 °, and the diffraction angle of 2θ = 16. The peak intensity (о) of the orthorhombic crystal including the mirror surface (100) of the orthorhombic crystal including Y ₇ O ₆ F ₉ and Y ₅ O ₄ F ₇ near 1 ° is used. (О) / Calculated by the peak intensity of rhombohedral crystals (r1) × 100 (%).

4 (a), 4 (b) and 5 are graphs showing X-ray diffraction in a sample of the structure.
In each of FIGS. 4 (a), 4 (b) and 5, the horizontal axis represents the diffraction angle 2θ and the vertical axis represents the intensity. As shown in FIGS. 4A and 5, samples 1 to 10 contain rhombohedral yttrium oxyfluoride (for example, YOF polycrystal), and each sample has a diffraction angle of around 2θ = 13.8 °. Peak Pr1 is detected. Further, as shown in FIG. 4B, peak Pr2 is detected in the vicinity of the diffraction angle 2θ = 36.1 ° in each of the samples 3, 4, 6 to 10. In Samples 1 and 2, no peak is detected near the diffraction angle 2θ = 36.1 °.

Further, as shown in FIGS. 4 (a) and 5, samples 3 to 7 are obtained by at least one of orthorhombic yttrium oxyfluoride (for example, Y ₅ O ₄ F ₇ or Y ₇ O ₆ F ₉ ). Crystal) is included, and a peak Pо is detected near a diffraction angle of 2θ = 16.1 °. In Samples 1, 2, 8 to 10, no peak is detected near the diffraction angle 2θ = 16.1 °.

For each sample, the above-mentioned peak intensities (r1 and r2) were calculated excluding the background intensity in the data shown in FIGS. 4 (a) and 4 (b), and the ratio γ1 with respect to the peak intensity of the rhombohedral crystal was obtained. Be done. Further, for each sample, the above-mentioned peak intensities (r1 and о) are calculated by excluding the background intensity from the data shown in FIG. 5, and the ratio γ2 of orthorhombic crystals to rhombohedral crystals is obtained. The obtained ratio γ1 and ratio γ2 are shown in FIG.

As shown in FIG. 3, the ratio γ1 changes greatly depending on the combination of the raw material and the film forming conditions. The inventors of the present application have obtained a new finding that there is a relationship between the orientation of yttrium oxyfluoride in rhombohedral crystals and plasma resistance.
Further, the ratio γ2 also changes greatly depending on the combination of the raw material and the film forming conditions. The inventors of the present application have discovered for the first time that the proportion of the compound in the structure changes depending on the film forming conditions and the like. For example, in raw material powders having a high oxygen content such as raw materials F1 to F5, the ratio γ2 of orthorhombic crystals to rhombohedral crystals is 50% or more and 100% or less. On the other hand, due to the film formation by the aerosol deposition method, the ratio γ2 becomes 0% in Samples 1 and 2 and exceeds 100% in Sample 7.
In all of the samples 1 to 10, no intensity peak was detected in the vicinity of the diffraction angle 2θ = 29.1 °. That is, excluding the background intensity, the ratio of the peak intensity ε to the peak intensity r1 (ε / r1) was 0%, and the samples 1 to 10 did not contain Y ₂ O ₃ .

In addition, the plasma resistance of these samples 1 to 7 was evaluated.
A plasma etching apparatus and a surface shape measuring instrument were used to evaluate the plasma resistance of yttrium oxyfluoride.
"Muc-21 Rv-Aps-Se / manufactured by Sumitomo Precision Products" was used for the plasma etching apparatus. The plasma etching conditions were an ICP output of 1500 W as a power supply output, a bias output of 750 W, a mixed gas of CHF ₃ 100 ccm and O ₂ 10 ccm as a process gas, a pressure of 0.5 Pa, and a plasma etching time of 1 hour.

"Surfcom 1500DX / Tokyo Seimitsu" was used as the surface roughness measuring instrument. Arithmetic mean roughness Ra was used as an index of surface roughness. For the Cut Off and the evaluation length in the measurement of the arithmetic mean roughness Ra, standard values suitable for the arithmetic mean roughness Ra of the measurement results based on JISB0601 were used.

Using the surface roughness Ra ₀ before plasma etching of the sample and the surface roughness Ra ₁ after plasma etching of the sample, the plasma resistance is determined by the amount of change in surface roughness (Ra _1- Ra ₀ ). evaluated.

FIG. 3 shows the evaluation results of plasma resistance. “○” indicates that the plasma resistance is higher than that of the yttria sintered body. “⊚” indicates that the plasma resistance is higher than that of “〇” and is equal to or higher than that of the yttria structure produced by the aerosol deposition method. “Δ” indicates that the plasma resistance is lower than that of “〇” and is equivalent to that of the yttria sintered body. “X” indicates that the plasma resistance is lower than that of “Δ”.

The inventors of the present application have found that there is a correlation between plasma resistance and the ratio γ1 as shown in FIG. That is, the plasma resistance is low in the samples 6 and 7 in which the ratio γ1 is 100% or more. By controlling the ratio γ1 to less than 100% depending on the film forming conditions and the like, the plasma resistance can be enhanced and a practically sufficient plasma resistance can be obtained.

By setting the ratio γ1 to less than 80%, the plasma resistance can be made higher than that of the yttria sintered body as in Samples 3, 4, 9, and 10.
By setting the ratio γ1 to 0%, the plasma resistance as in Samples 1, 2 and 8 can be increased to the same level as or higher than that of the yttria structure produced by the aerosol deposition method.

Furthermore, the inventors of the present application have found that there is a correlation between plasma resistance and the ratio γ2, as shown in FIG. That is, the plasma resistance is low in the sample 7 in which the ratio γ2 is 106% or more. In the structure 20 according to the embodiment, the plasma resistance can be enhanced and a practically sufficient plasma resistance can be obtained by controlling the ratio γ2 to less than 100% by adjusting the film forming conditions and the like.

By setting the ratio γ2 to 85% or less, preferably 70% or less, the plasma resistance can be increased to the same level as that of the yttria sintered body as in Samples 5 and 6.
By setting the ratio γ2 to 30% or less, the plasma resistance can be increased to the same level as that of the yttria structure by the aerosol deposition method as in Samples 3 and 4.
By setting the ratio γ2 to 0%, the plasma resistance can be further enhanced as in Samples 1 and 2.

It is generally known that when an oxide structure such as Al ₂ O ₃ or Y ₂ O ₃ is formed by using the aerosol deposition method, the structure has no crystal orientation.
On the other hand, since YF ₃ and yttrium oxyfluoride have cleavage properties, for example, the fine particles of the raw material are easily cracked along the cleavage surface by applying a mechanical impact. Therefore, it is considered that the fine particles are cracked along the cleavage plane during film formation due to the mechanical impact force, and the structure is oriented in a specific crystal direction.

Further, when the raw material has cleavage property, if the structure is damaged by plasma irradiation, cracks may occur along the cleavage surface, and particles may be generated from the cracks. Therefore, when the structure is formed, the fine particles are crushed along the cleavage plane in advance to adjust the orientation. Specifically, the ratios γ1 and γ2 are adjusted. It is considered that this makes it possible to improve the plasma resistance.

The embodiments of the present invention have been described above. However, the present invention is not limited to these descriptions. With respect to the above-described embodiment, those skilled in the art with appropriate design changes are also included in the scope of the present invention as long as they have the features of the present invention. For example, the shape, dimensions, material, arrangement, etc. of the structure, the base material, etc. are not limited to those exemplified, and can be changed as appropriate.
In addition, the elements included in each of the above-described embodiments can be combined as much as technically possible, and the combination thereof is also included in the scope of the present invention as long as the features of the present invention are included.

10 members, 15 substrates, 20, 20a structures, 20c crystallites, Po, Pr1, Pr2 peaks

Claims (13)

A structure containing a polycrystal of yttrium oxyfluoride having a rhombic crystal structure as a main component and having an average crystallite size of less than 100 nanometers in the polycrystal.
The peak intensity of the rhombohedral crystal detected near the diffraction angle 2θ = 13.8 ° by X-ray diffraction is r1, and the peak intensity of the rhombohedral crystal detected near the diffraction angle 2θ = 36.1 ° is r2. A structure in which the ratio γ1 is 0% or more and less than 100% when the ratio γ1 is γ1 (%) = r2 / r1 × 100. The structure according to claim 1, wherein the ratio γ1 is less than 80%. The structure is
It does not contain yttrium oxyfluoride or has an orthorhombic crystal structure.
It further contains yttrium oxyfluoride having an orthorhombic crystal structure, and the peak intensity of the orthorhombic crystal detected at a diffraction angle of 2θ = 16.1 ° by X-ray diffraction is defined as о, and the orthorhombic crystal with respect to the rhorhombic crystal. The structure according to claim 1 or 2, wherein when the ratio of γ2 (%) = о / r1 × 100, the ratio γ2 is 0% or more and less than 100%. The structure according to any one of claims 1 to 3, wherein the yttrium oxyfluoride having a rhombohedral crystal structure is YOF. The structure according to claim 3, wherein the yttrium oxyfluoride having an orthorhombic crystal structure has a YOF of 1: 1: 2. The structure according to claim 3, wherein the ratio γ2 is 85% or less. The structure according to claim 3, wherein the ratio γ2 is 70% or less. The structure according to claim 3, wherein the ratio γ2 is 30% or less. The structure according to any one of claims 1 to 8, wherein the average crystallite size is less than 50 nanometers. The structure according to any one of claims 1 to 8, wherein the average crystallite size is less than 30 nanometers. The structure according to any one of claims 1 to 8, wherein the average crystallite size is less than 20 nanometers. When the peak intensity detected near the diffraction angle 2θ = 29.1 ° by X-ray diffraction is ε, at least one of the ratio of the ε to the r1 and the ratio of the ε to the r2 is less than 1%. The structure according to any one of claims 1 to 11. When the peak intensity detected in the vicinity of the diffraction angle 2θ = 29.1 ° by X-ray diffraction is ε, at least one of the ratio of the ε to the r1 and the ratio of the ε to the r2 is 0%. The structure according to any one of claims 1 to 11.