TW202334061A - Material for sintered body, and sintered body - Google Patents

Abstract

This material for a sintered body contains an oxyfluoride of a rare earth element represented by REaObFc (where, RE is the rare earth element, b/a is at most 0.9, and c/a is at least 1.1), and has a molar ratio (F/RE molar ratio) of moles of fluorine (F) to moles of the rare earth element (RE) in the entirety of the material is 1.3 to 2.8, and the content of aluminum (Al) is at most 50 mass ppm. The content of silicon (Si) is preferably at most 500 mass ppm.

Description

Materials for sintered bodies and sintered bodies

The present invention relates to a sintered body material containing an oxyfluoride of a rare earth element and a sintered body.

Rare earth oxides such as Y ₂ O ₃ , fluorides of rare earth elements such as YF ₃ (hereinafter sometimes referred to as "rare earth fluorides"), and oxyfluorides of rare earth elements such as Y ₅ O ₄ F ₇ (hereinafter sometimes referred to as "rare earth fluorides") , sometimes described as "rare earth oxyfluoride") is a corrosion-resistant ceramic, so its film or sintered body is used as a protective material in the semiconductor manufacturing process. In particular, compounds containing rare earth oxyfluorides are known to have high chemical plasma resistance or to shorten the aging treatment time of semiconductor manufacturing equipment.

According to Patent Document 1, by using oxyfluoride of a rare earth element, the sprayed film produced using its sprayed particles shows excellent corrosion resistance to both F-based plasma and Cl-based plasma, and This reduces particles scraped and scattered due to etching during plasma etching.

On the other hand, as shown in Patent Document 2, studies have also been conducted on improving the barrier function of halogen-based corrosive gases by using a sintered body that is denser than a melt-sprayed film. Furthermore, Patent Document 3 discloses a sintering material using particles of oxyfluoride (Ln-O-F) containing rare earth elements, which contains particles of oxyfluoride containing rare earth elements. According to the tapping method, the density is within a specific range and has a specific particle size. The sintered body produced using the material for sintering has high corrosion resistance and is dense in chlorine-based plasma. Prior technical literature patent documents

Patent Document 1: US2015/096462A1 Patent Document 2: US2017/0305796 A1 Patent document 3: US2018/0016193 A1

However, in the rare earth oxyfluoride sintered body produced by using the previous rare earth oxyfluoride sintered body material, the corrosion resistance in various plasmas used in dry etching or chemical liquids used in wet etching There is room for improvement in sex.

Therefore, an object of the present invention is to provide a sintered body material and a sintered body that can eliminate the above-mentioned shortcomings of the prior art.

Regarding materials for sintered bodies and sintered bodies using rare earth oxyfluoride, the present inventors have conducted intensive research on structures that effectively improve the corrosion resistance in plasma used for dry etching or chemical solutions used for wet etching. As a result, it was found that by using a material for the sintered body that has an F/RE molar ratio within a specific range and contains an oxyfluoride of a rare earth element with a specific composition, and the aluminum (Al) content is 50 ppm or less, the obtained The sintered body is dense and hard, and has excellent chemical resistance and plasma resistance.

Therefore, the present invention provides the following [1] to [14]. [1] A material for sintered bodies containing an oxyfluoride of a rare earth element represented by REaObFc (where RE is a rare earth element, b/a is 0.9 or less, and c/a is 1.1 or more), and in the entire material The ratio of the molar number of the fluorine element (F) to the molar number of the rare earth element (RE) (F/RE molar ratio) is 1.3 or more and 2.8 or less, and the aluminum (Al) content is 50 mass ppm or less. [2] The material for sintered bodies according to [1], wherein the content of silicon (Si) is 500 ppm by mass or less. [3] The material for sintered bodies as described in [1] or [2], which has a pore diameter distribution measured using a mercury porosimetry in the range of 0.05 μm to 0.5 μm and a pore diameter of 5 There are peaks in the range of 50 μm to 50 μm. The pore volume of pore diameters of 0.05 μm to 0.5 μm is 0.1 mL/g or more, and the pore volume of 5 μm to 50 μm is 0.1 mL/g or more. . [4] The material for sintered bodies according to any one of [1] to [3], which contains, in XRD (X-ray diffraction, X-ray diffraction) analysis, in addition to oxyfluoride of rare earth elements The crystalline phase is essentially composed only of fluorides of rare earth elements represented by REF ₃ . [5] The material for sintered bodies according to any one of [1] to [4], wherein REaObFc is selected from RE ₇ O ₆ F ₉ , RE ₆ O ₅ F ₈ , RE ₅ O ₄ F ₇ , RE At least one of ₄ O ₃ F ₆ , RE ₃ O ₂ F ₅ and RE ₂ OF ₄ . [6] The material for sintered bodies according to any one of [1] to [5], wherein the rare earth element RE of the rare earth element oxyfluoride is selected from the group consisting of Sc, Y, La, Ce, Pr, and Nd , one or more of Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. [7] The material for sintered bodies according to any one of [1] to [6], which has a loss on ignition of 10 mass % or less. [8] The material for sintered bodies according to any one of [1] to [7], which has a BET specific surface area of 2 m ² /g or more and 10 m ² /g or less. [9] The material for sintered bodies according to any one of [1] to [8], which has a Hausner ratio (tap density/bulk density) of 1.0 or more and 1.3 or less. [10] A sintered body containing an oxyfluoride of a rare earth element represented by REaObFc (where RE is a rare earth element, b/a is 0.9 or less, and c/a is 1.1 or more), and fluorine in the entire sintered body The ratio of the molar number of the element (F) to the molar number of the rare earth element (RE) (F/RE molar ratio) is 1.3 or more and 2.8 or less, and the aluminum (Al) content is 50 mass ppm or less. [11] The sintered body according to [10], wherein the silicon (Si) content is 500 ppm by mass or less. [12] The sintered body as described in [10] or [11], in which the crystal phase other than the oxyfluoride of the rare earth element is substantially composed only of the fluoride of the rare earth element represented by REF ₃ . [13] The sintered body according to any one of [10] to [12], having a Vickers hardness of 3 GPa or more. [14] A method for producing a sintered body, which includes sintering the material for a sintered body according to any one of [1] to [9].

Hereinafter, the present invention will be described based on its preferred embodiments. First, the materials for sintered bodies will be described. The material for sintered bodies of the present invention is characterized by containing rare earth represented by REaObFc (where RE is a rare earth element, b/a is 0.9 or less, c/a is 1.1 or more, and is also referred to as "REaObFc" below). Oxyfluorides of similar elements, and the ratio of the molar number of fluorine element (F) to the molar number of rare earth elements (RE) in the entire material (hereinafter, also referred to as "F/RE molar ratio" ) is above 1.3 and below 2.8.

The inventors of the present invention studied the corrosion resistance of a sintered body using an oxyfluoride of a rare earth element in a plasma used for dry etching or a chemical liquid used for wet etching. As a result, the following problems were found: REaObFc is contained, and Materials for sintered bodies whose F/RE molar ratio is 1.3 or more and 2.8 or less are difficult to obtain dense and hard sintered bodies, so it is difficult to improve plasma resistance or chemical resistance. Furthermore, we conducted research on the reasons and found out the following.

Previously, when producing oxyfluorides of rare earth elements such as REaObFc, rare earth fluorides, hydrofluoric acid (hereinafter also referred to as "hydrofluoric acid"), ammonium fluoride or acidic ammonium fluoride were used as fluorine sources. For example, hydrofluoric acid is added to an oxide of a rare earth element to prepare a fluoride precursor of the rare earth element, and the precursor is calcined to obtain a fluoride of the rare earth element (REF ₃ ). In addition, the oxyfluoride of the rare earth element is obtained by calcining the fluoride of the rare earth element, or by mixing the fluoride of the rare earth element and the oxide of the rare earth element and then calcining. Generally speaking, each of the above-mentioned baking steps is usually performed at high temperature using an electric furnace. However, in this case, porous saggers containing Al, such as alumina or mullite, or Al and Si are widely used. Porous saggers containing Al or Al and Si, such as alumina or mullite, are commonly used because they are cheap and highly durable.

The present inventors have found that fluorine of rare earth elements is produced by using a porous sagger containing Al or Al and Si such as alumina or mullite and calcining the fluoride of rare earth elements or its precursor at high temperature. The oxide contains a lot of Al or Al and Si. Furthermore, it is speculated that the reason for this is that when the fluoride of rare earth elements or the fluorine source of its precursor is heated at high temperature, a large amount of fluorine gas is generated, which reacts with the Al component or Si component in the sagger and is contained in the sagger. In fluoride oxides of rare earth elements.

Furthermore, the present inventors used yttrium oxide saggers, zirconia saggers, or platinum dishes, which are made of materials that contain almost no Al, especially Al and Si, and fired them in a certain low-temperature region, thereby successfully achieving a significant reduction in Fluorine gas is generated, and a material for producing a sintered body containing REaObFc containing Al, especially Al and Si, is small.

Surprisingly, it was found that a sintered body containing REaObFc-containing material with a low content of Al, especially Al and Si, is dense and has high hardness. The inventor believes that the reason is that as the temperature rises during sintering, the Al component or the Si component reacts with the F component to form a different phase between the grain boundaries or become a volatile component, thereby suppressing the formation of open or closed pores in the sintered body. . In addition, if the content of Al and Si in the material for sintered body is less than a specific value, the Al and Si on the outermost surface of the obtained sintered body will be reduced. In this regard, the inventor believes that it is possible to further increase the content easily. Corrosion resistance in fluorine-based corrosive gases or fluorine-based chemical liquids.

In particular, conventional materials for sintered bodies containing REaObFc and having an F/RE molar ratio of 1.3 to 2.8 tend to produce sintered bodies that do not easily gain density or hardness. The material for sintered bodies of this composition contains many fluorine components. Therefore, it is considered that one of the reasons for the above situation is that since the Al component or Si component previously existed in the sintered body material of this composition, these different phases react with the fluorine component during sintering, and open pores or closed pores are easily generated. In the present invention, by reducing the content of Al, especially the content of Al and Si, the formation of open pores or closed pores can be effectively suppressed. By including REaObFc, the corrosion resistance in plasma or chemical liquid can be effectively exerted. sex. On the other hand, when a sintered body is produced using a sintered body material in which the rare earth oxyfluoride is composed only of REOF (RE ₁ O ₁ F ₁ ) and the overall F/RE molar ratio is 1.0 or more and 2.8 or less, there may be cases where By reducing the Al content of the sintered body material, especially the Al and Si content, it is difficult to fully obtain the effect of increasing density or hardness. The reason for this is speculated as follows. For REOF (RE ₁ O ₁ F ₁ ), such as YOF, a reversible phase transition is observed near 570°C by TG-DTA (Thermo-Gravimetric/Differential Thermal analysis, differential thermogravimetric analysis). Therefore, it is considered that the reason is that compared with containing an Al component or a Si component, the influence of this phase transition becomes a main cause of micro cracks and pores. On the other hand, in the sintered body material containing REaObFc and having an overall F/RE molar ratio of 1.3 or more and 2.8 or less, for example, the sintered body material containing Y ₅ O ₄ F ₇ is not formed by TG- Reversible phase transfer was observed with DTA. Due to the low content of Al, especially the low content of Al and Si, the effect of increasing hardness and density is fully exerted. In terms of exhibiting these effects, materials for sintered bodies containing REaObFc represented by Y ₅ O ₄ F ₇ and the like and having an overall F/RE molar ratio of 1.3 to 2.8 are considered to be of particular technical significance.

In order to make the above-mentioned effect of the present invention more excellent, b/a in REaObFc is preferably 0.5 or more and 0.9 or less. On the other hand, c/a is preferably 1.1 or more and 2.0 or less. By setting b/a to be 0.9 or less and c/a to be 1.1 or more, the composition does not contain REOF (RE ₁ O ₁ F ₁ ), so reversible phase transition does not occur. In this way, the hardness or density improvement effect caused by the lower Al content, especially the lower Al and Si content, can be greater. Moreover, it is preferable in terms of ease of acquisition when b/a is 0.5 or more and c/a is 2.0 or less. From these points of view, b/a in REaObFc is further preferably 0.6 or more and 0.8 or less, and c/a is further preferably 1.3 or more and 1.7 or less. Furthermore, usually 3a=2b+c.

In particular, REaObFc is preferably selected from the group consisting of RE ₇ O ₆ F ₉ and RE ₆ O ₅ F in order to achieve a greater effect of increasing the hardness or density due to the low Al content or Si content. _8. At least one of RE ₅ O ₄ F ₇ , RE ₄ O ₃ F ₆ , RE ₃ O ₂ F ₅ and RE ₂ OF ₄ , preferably RE ₅ O ₄ F ₇ .

By setting the F/RE molar ratio of the material for sintered bodies to 1.3 or more, the effect of increasing the hardness or density due to low Al content or Si content can be greater. Furthermore, by setting the F/RE molar ratio in the material for the sintered body to 2.8 or less, the content of REF ₃ having a single composition and cleavage properties can be controlled, making it easier to produce a sintered body. From this point of view, the F/RE molar ratio of the material for sintered bodies is preferably 1.4 or more and 2.6 or less, and particularly preferably 1.5 or more and 2.4 or less. The F/RE molar ratio can be measured by the method described in the following examples.

By setting the Al content in the material for the sintered body to 50 mass ppm or less, the obtained sintered body is hard and dense, and corrosion resistance to plasma or chemical liquid treatment can be obtained. If the Al content is 1 mass ppm or more, it is advantageous in terms of productivity in manufacturing and a very small amount of Al functions as a sintering aid, so it is preferable. From these points of view, the Al content in the material for sintered bodies is more preferably from 1 mass ppm to 35 mass ppm, and further preferably from 1 mass ppm to 25 mass ppm.

Furthermore, by setting the Si content in the material for the sintered body to 500 ppm by mass or less, the obtained sintered body is harder and denser, and corrosion resistance to plasma or chemical liquid treatment can be obtained, which is preferable. If the Si content is 1 mass ppm or more, it is advantageous in terms of productivity in manufacturing, and there is an advantage that a very trace amount of Si functions as a sintering aid. From these points of view, the Si content in the material for sintered bodies is more preferably from 1 mass ppm to 350 mass ppm, and further preferably from 1 mass ppm to 200 mass ppm.

The Al content and Si content can be measured by the methods described in the following examples.

In terms of ease of acquisition or chemical stability of the material for the sintered body, the rare earth element RE of the oxyfluoride of the rare earth element is preferably selected from Sc and Y other than Pm which is a non-naturally occurring radioactive element. , one or more of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, preferably selected from Y, La, Gd, Er, Yb One or more of Lu, more preferably Y, Gd, Yb, and most preferably Y.

In the present invention, when the rare earth fluoride represented by REF ₃ is mixed with the material for sintered body in addition to REaObFc, compared with the case where only REaObFc is contained, the sintered body obtained from the material for sintered body is The hardness of the body is further improved, so it is better. The present inventors believe that the reason for this is that the presence of the rare earth fluoride appropriately suppresses the grain growth, resulting in a sintered body having an appropriate grain size that can withstand physical load.

When the material for the sintered body contains a fluoride of a rare earth element, the rare earth element RE may be the same element as the rare earth element RE exemplified above as an oxyfluoride. For the sintered body, In terms of ease of acquisition or chemical stability of the material, it is preferable to be selected from Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, and Tb except Pm, which is a radioactive element that is not naturally occurring. , Dy, Ho, Er, Tm, Yb and Lu, one or more of them, more preferably one or more of Y, La, Gd, Er, Yb, Lu, more preferably Y, Gd, Yb, the best is Y. When the material for sintered body of the present invention contains REaObFc and the fluoride of the rare earth element represented by REF ₃ , the rare earth element RE represented by REaObFc and REF ₃ may be the same or different.

The material for the sintered body of the present invention is preferably one in which the crystalline phase other than the oxyfluoride of the rare earth element is substantially composed only of the fluoride of the rare earth element represented by REF ₃ in XRD analysis. "Crystal phases other than oxyfluorides of rare earth elements are essentially composed only of fluorides of rare earth elements represented by REF ₃ " preferably means that CuKα line is used and 2θ=20 to 60° is used. In the XRD analysis of the scanning range, the main peak derived from the crystal phase of compounds other than oxyfluorides of rare earth elements and fluorides of rare earth elements represented by REF ₃ (hereinafter, sometimes also described as "other components") The peak height relative to the peak height of the main peak derived from the crystal phase of REaObFc is 10% or less, more preferably 5% or less, further preferably 3% or less, most preferably 1% or less. Therefore, in the above XRD analysis, the peak height of the main peak of the crystal phase derived from the compound of the oxide of the rare earth element other than RE ₂ O ₃ is preferably relative to the peak height of the main peak of the crystal phase derived from REaObFc It is 10% or less, more preferably 5% or less, still more preferably 3% or less, most preferably 1% or less.

Furthermore, in the XRD analysis of the material for sintered bodies of the present invention (specifically, XRD analysis using CuKα line and 2θ=20 to 60° as the scanning range), it was observed that the material originates from rare earth elements other than REaObFc. In the case of the peak of the oxyfluoride, the peak height of the peak is preferably 10% or less, more preferably 5% or less, relative to the peak height of the main peak derived from the crystal phase of REaObFc.

The material for sintered bodies of the present invention preferably contains REaObFc as the main phase. Here, using REaObFc as the main phase means that in XRD analysis using CuKα line and 2θ=20 to 60° as the scanning range, the peak originating from REaObFc is the peak with the maximum height.

Furthermore, even when the material for sintered bodies of the present invention does not have REaObFc as the main phase, the ratio of the peak height of the main peak of REaObFc to the height of the main peak of the crystalline phase of the rare earth element fluoride represented by REF ₃ is also More preferably, it is 50% or more, and more preferably, it is 80% or more.

The main peak of Y ₅ O ₄ F ₇ is usually observed at 2θ=28.11°. In addition, the main peak of Y ₆ O ₅ F ₈ is usually observed at 2θ=28.14°. In addition, the main peak of Y ₇ O ₆ F ₉ is usually observed at 2θ=28.14°. The main peak of La ₁₀ O ₇ F ₁₆ is usually observed at 2θ=26.52°. The main peak of Gd ₄ O ₃ F ₆ is usually observed at 2θ=27.59°. The main peak of Er ₅ O ₄ F ₇ is usually observed at 2θ=28.25°. The main peak of Yb ₅ O ₄ F ₇ is usually observed at 2θ=28.50°. The main peak of Lu ₇ O ₆ F ₉ is usually observed at 2θ=28.60°. In addition, the main peak of YF ₃ is usually observed at 2θ=27.88°. The main peak of LaF ₃ is usually observed at 2θ=27.60°. The main peak of GdF ₃ is usually observed at 2θ=27.54°. The main peak of ErF ₃ is usually observed at 2θ=27.95°. The main peak of YbF ₃ is usually observed at 2θ=27.98°. The main peak of LuF ₃ is usually observed at 2θ=27.97°. Among them, when REaObFc and REF ₃ are observed, such as Y ₅ O ₄ F ₇ and YF ₃ , Gd ₄ O ₃ F ₆ and GdF ₃ , Er ₅ O ₄ F ₇ and ErF _3, they are formed by a combination of compositions. The detection of the main peaks at positions close to each other (the difference in 2θ is within 0.4°) can be measured by the following method. Specifically, the intensity ( _IS ) of the wave peak corresponding to the following specific surface can be divided by the relative intensity of the surface (the intensity of the main peak is 100, and the intensity in the PDF (Portable Document Format, Portable Document Format) card The recorded intensity: I _T ) is the value obtained as the intensity of the main peak (I _M ). ※I _M =I _S /I _T ×100 Y ₅ O ₄ F ₇ The peak of the (0100) plane is usually observed at 2θ = 32.29°, and its relative intensity relative to the main peak is 23.4%. The peak of the (100) plane of Gd ₄ O ₃ F ₆ is usually observed at 2θ=31.77°, and its relative intensity relative to the main peak is 14.5%. The peak of the (171) plane of Er ₅ O ₄ F ₇ is usually observed at 2θ=32.48°, and its relative intensity relative to the main peak is 14.2%. The specific peak of REF ₃ can be set to the peak of the (020) plane. For example, the peak of the (020) plane of YF ₃ is usually observed at 2θ=25.98°, and its relative intensity relative to the main peak is 67.6%. The peak of the (020) plane of GdF ₃ is usually observed at 2θ=25.47°, and its relative intensity relative to the main peak is 60.0%. The peak of the (020) plane of ErF ₃ is usually observed at 2θ=26.03°, and its relative intensity relative to the main peak is 75.0%. The error of the above-mentioned wave crest position is preferably within ±0.05°, more preferably within ±0.03°, further preferably within ±0.02°, and most preferably within ±0.01°. Regarding the content of the main peak ratio of REaObFc and REF ₃ recorded in this specification, it can be in any of the following situations: when the peak height (intensity) of the main peak itself is used to calculate the main peak height ratio; when the main peak height ratio is calculated using the above-mentioned When calculating the main peak height ratio, it is consistent to calculate the main peak height ratio by dividing the peak height (intensity) of the main peak recorded in the PDF card by the relative intensity when the height (intensity) of the main peak recorded in the PDF card is set to 100. When both methods can be measured, as long as it is consistent with the ratio described in this specification in one situation, it will be deemed to be consistent even if it is not consistent in another situation.

When the material for sintered bodies of the present invention contains REF ₃ , in order to obtain the above-mentioned effect of containing REF ₃ , the height ratio of the main peak of REF ₃ to the height of the main peak of REaObFc is preferably 1% or more. More preferably, it is 5% or more, and still more preferably, it is 10% or more. As mentioned above, regarding the height ratio of the main peaks of REF ₃ and REaObFc, which are referred to in this specification, when the main peaks are close to each other (within 0.4° in 2θ), the peaks corresponding to the above-mentioned specific planes can be used respectively. The intensity ratio ( _IS ) divided by the relative intensity of the specific surface (intensity recorded in the PDF card: I _T ) is the value obtained as the intensity of the main peak (I _M ). Furthermore, in the above description, "strength" is described because the PDF card describes the "strength" of the crest, so it is synonymous with the "height" of the crest in this manual.

The X-ray diffraction measurement of the material for sintered body can be measured by the method described in the following Examples. It is not limited to the X-ray diffraction measuring device used in the following Examples, and any device with an accuracy equal to or higher than the X-ray diffraction measuring device can be used.

The material for the sintered body preferably has a pore diameter distribution measured using a mercury porosimetry method in which the pore volume of a pore diameter of 0.05 μm or more and 0.5 μm or less is a specific value or less. This pore volume originates from the gaps between primary particles in the material for sintered bodies of the present invention. If the pore volume of the pore diameter in this range is 0.1 mL/g or more, the primary particles constituting the particles are relatively small and have a pore volume of more than a certain level, thereby efficiently conducting heat and easily obtaining a dense sintered body that is easy to melt. . From the viewpoint of improving the corrosion resistance of the obtained sintered body in plasma or chemical solution, the pore diameter is 0.05 μm or more and 0.5 μm or less and the pore volume is more preferably 0.1 mL/g or more, and still more preferably 0.13 mL. /g or above. In view of the fact that if the gaps between the primary particles expand excessively, the particle strength will decrease, the pore diameter of the powder of the present invention is 0.05 μm or more and 0.5 μm or less, and the pore volume is preferably 0.23 mL/g or less, more preferably 0.2 mL. /g or less. Hereinafter, the volume of pores with a pore diameter of 0.05 μm or more and 0.5 μm or less may be described as "pore first volume". In this specification, pore diameter means pore diameter.

In materials for sintered bodies, in order to improve corrosion resistance, it is also preferable that the pore diameter is 5 μm or more and 50 μm or less and the pore volume is 0.1 mL/g or more. The pore diameter is 5 μm or more and the pore volume is 50 μm or less. The pore volume is derived from the space between the secondary particles in the material for sintered body. The pore volume in the material for sintered body is more preferably 0.1 mL/g or more, and particularly preferably 0.2 mL/g or more. In order to ensure sufficient fluidity, the pore volume of the material for sintered body is preferably 0.4 mL/g or less, more preferably 0.3 mL/g or less. Hereinafter, the volume of pores with a pore diameter of 5 μm or more and 50 μm or less may be described as "pore second volume".

From the viewpoint of further improving the corrosion resistance of the obtained sintered body, the distribution of pore volume relative to the pore diameter measured using the mercury porosimetry method (horizontal axis: pore diameter; vertical axis: logarithmic differential fineness) Pore volume), at least one peak is observed in the range of pore diameter from 0.05 μm to 0.5 μm. From the viewpoint of improving the corrosion resistance more effectively, it is more preferable that at least one wave peak is observed in the range of the pore diameter of 0.05 μm to 0.5 μm, more specifically, the pore diameter is in the range of 0.08 μm to 0.35 μm. , it is particularly preferable to observe at least one in the range of pore diameter from 0.1 μm to 0.2 μm. Hereinafter, the peak in the pore volume distribution in the range of pore diameters from 0.05 μm to 0.5 μm may be described as the first pore peak.

From the viewpoint of further improving corrosion resistance, the material for sintered bodies of the present invention preferably has a distribution of pore volume relative to pore diameter measured using the mercury porosimetry method (horizontal axis: pore diameter; vertical axis: logarithmic differential Pore volume), in addition to at least one peak being observed in the range of pore diameters from 0.05 μm to 0.5 μm, at least one peak is also observed in the range of pore diameters from 5 μm to 50 μm. In order to further improve the ease of production of the material for the sintered body of the present invention or the corrosion resistance of the sintered body, the peak in the range of the pore diameter is 5 μm or more and 50 μm or less. More specifically, it is more preferable that the pore diameter is in the range of 5 μm to 50 μm. At least one is observed in the range of 8 μm to 35 μm, and particularly preferably, at least one is observed in the range of 10 μm to 20 μm. Hereinafter, the peak in the pore volume distribution in the range of pore diameters from 5 μm to 50 μm may be described as the second peak of pores.

Regarding the sintered body material having the above-mentioned preferred characteristics in pore size distribution, the sintered body material of the present invention is produced by the following preferred manufacturing method, and the grinding conditions in the fourth step or the rotation speed of the spray dryer or the drying conditions are adjusted. That’s it.

The ignition loss of the material for sintered bodies of the present invention after baking in the air at 550° C. for 2 hours is preferably 10 mass% or less. When the material for sintered bodies of the present invention has this structure, since the ratio of components that are not volatilized by sintering is high, it is easy to obtain a dense and high-hardness sintered body. From this point of view, the ignition loss of the material for sintered body is more preferably 7 mass % or less, and particularly preferably 5 mass % or less. The loss on ignition can be measured by the method described in the following examples. A material for a sintered body whose loss on ignition is less than or equal to the above-mentioned upper limit can be obtained by adjusting the amount of the organic binder or suppressing the inclusion of hydroxyl groups or moisture in the preferable manufacturing method described below.

The BET specific surface area of the material for sintered bodies of the present invention is preferably 2 m ² /g or more and 10 m ² /g or less. In terms of easy sintering, the BET specific surface area is preferably 2 m ² /g or more. The BET specific surface area is preferably 10 m ² /g or less in order to easily improve the fluidity in the granular state, increase the density of the compact, improve the shrinkage during sintering, and easily obtain the target sintered compact size. From these points of view, the BET specific surface area of the material for sintered body is more preferably 3 m ² /g or more and 7 m ² /g or less. Regarding the material for sintered body whose BET specific surface area is within the above range, the material for sintered body of the present invention is produced by the following preferred manufacturing method, and the grinding conditions in the grinding step of the fourth step or the drying of the spray dryer are adjusted. Conditions are enough.

The ratio of tap density to bulk density (tap density/bulk density) of the material for sintered bodies of the present invention, that is, the Hausner ratio, is preferably 1.0 or more and 1.3 or less. In order to improve fluidity and make it easier to produce a uniform molded body, the Hausner ratio of the material for the sintered body is preferably 1.3 or less. From this point of view, the Hausner ratio of the material for sintered body is more preferably 1.0 or more and 1.2 or less.

In order to further enhance the effect of having a Hausner ratio of 1.0 to 1.3, the tap density of the sintered body material (also called tap apparent density, abbreviated as TD) is preferably 1.4 g. /cm ³ or more and 2.8 g/cm ³ or less, and more preferably 1.6 g/cm ³ or more and 2.6 g/cm ³ or less.

In order to further enhance the effect of having a Hausner ratio of 1.0 to 1.3, the bulk density of the material for the sintered body (also called the standing apparent density. Abbreviation: AD) is preferably 1.1 g/ cm ³ or more and 2.4 g/cm ³ or less, and more preferably 1.3 g/cm ³ or more and 2.2 g/cm ³ or less.

Regarding the material for sintered body whose Hausner ratio, bulk density, and tap density are within the above range, the material for sintered body of the present invention is produced by the following preferred manufacturing method, and the grinding conditions or spray dryer spraying are adjusted. The slurry concentration is sufficient.

In the material for sintered bodies of the present invention, the average particle diameter is preferably 10 μm or more and 100 μm or less. By setting the average particle diameter of the material for sintered body to 10 μm or more, the fluidity becomes better and it becomes easier to produce a uniform shaped body (molded body). In addition, if the average particle diameter of the material for sintered body is 100 μm or less, the material processing properties will be better. From these viewpoints, the average particle size of the material for sintered bodies is preferably from 20 μm to 80 μm, and more preferably from 30 μm to 60 μm. The average particle diameter here refers to the average particle diameter measured before the ultrasonic dispersion treatment of the material for sintered body. The average particle size is determined by the cumulative volume particle size D ₅₀ at 50% volume of the cumulative volume obtained by laser diffraction scattering particle size distribution measurement.

＜Manufacturing method of materials for sintered bodies＞ Next, a preferred method for producing the material for sintered bodies of the present invention will be described. This manufacturing method preferably has the following 1st step - 5th step. Each step is described in detail below. ・Step 1: React an aqueous solution of a rare earth compound (hereinafter, also referred to as "rare earth aqueous solution") with a fluorine-containing solution to obtain a fluoride precursor of a rare earth element (hereinafter, also referred to as "rare earth fluorine") Precipitate of "chemical precursor"). ・Step 2: Calculate the rare earth fluoride precursor at 300°C to 850°C in an environment where the Al mixed into the material is 50 ppm by mass or less (preferably 1 to 50 ppm by mass) to obtain the rare earth fluoride. ・Step 3: After mixing rare earth fluorides with oxides of rare earth elements and/or compounds of rare earth elements that become oxides after being baked in the atmosphere, the Al mixed into the material must be less than 50 ppm by mass. It is calcined at 500°C to 900°C in an environment (especially preferably 1 to 50 ppm by mass) to obtain a rare earth oxyfluoride represented by REaObFc or a mixture of the rare earth oxyfluoride and a rare earth fluoride. ・Step 4: Crush the rare earth oxyfluoride represented by REaObFc or the mixture of the rare earth oxyfluoride and the rare earth fluoride to obtain the rare earth oxyfluoride represented by REaObFc or the rare earth oxyfluoride and the rare earth Slurry of fluoride-like mixture. ・Step 5: Use a spray dryer to dry the slurry of the rare earth oxyfluoride represented by REaObFc or the mixture of the rare earth oxyfluoride and the rare earth fluoride to obtain the rare earth oxyfluoride or the rare earth oxyfluoride Particles of mixtures of substances and rare earth fluorides. Regarding the environment where the Al mixed in the material is 50 ppm by mass or less (preferably, 1 to 50 ppm by mass), the best is also an environment where the Al mixed in the material is 500 ppm by mass or less (preferably, 1 to 500 ppm by mass). environment.

[Step 1] In this step, a rare earth fluoride precursor is obtained. A fluorine-containing solution is added dropwise to the rare earth aqueous solution to form a precipitate. In terms of manufacturing cost, it is preferable to use one selected from the group consisting of an aqueous solution of a chloride of a rare earth element, an aqueous solution of a nitrate of a rare earth element, an aqueous solution of an acetate of a rare earth element, etc. as the rare earth aqueous solution. There are two or more types. In terms of the yield of the rare earth fluoride precursor, an aqueous solution of a chloride of a rare earth element or an aqueous solution of a nitrate is particularly preferred. In terms of manufacturing cost, as the fluorine-containing solution, it is preferable to use one or two or more selected from the group consisting of hydrofluoric acid aqueous solution (hydrofluoric acid), ammonium bifluoride aqueous solution, ammonium fluoride aqueous solution, etc., in the case of rare earth fluorine In terms of the yield of the compound precursor, it is particularly preferable to use an aqueous hydrofluoric acid solution (hydrofluoric acid). In addition, various additives such as a pH adjuster, a flocculant, or a dispersant can be added according to the purpose as long as they do not become a source of mixing of Al and Si. The obtained precipitate is washed and filtered to obtain a rare earth fluoride precursor. At this time, the washing and filtration of the sediment can be combined with one or more various washing and filtration devices such as vacuum filtration, centrifugal separator, centrifugal dewatering machine or filter press.

[Second step] In this step, the rare earth fluoride precursor obtained in the first step is fired to obtain rare earth fluoride powder. Drying, etc. may be carried out if necessary before roasting. An example of an environment where the mixing of Al and Si in the material is below the above-mentioned specific value is: in order to avoid the mixing of Al or Si during the baking of the rare earth fluoride precursor, a furnace material, a sagger or a dish that is in direct contact with the precursor Materials such as yttrium oxide (Y ₂ O ₃ ), zirconium oxide (ZrO ₂ ), or platinum (Pt) are used that contain as little Al or Si components as possible. In addition, regarding the temperature during baking, in order to minimize the fluorine gas generated from the precursor, it is preferable to bake at a temperature of 300°C to 850°C. It is more preferable to bake at 350°C to 800°C, and even more preferably to bake at 400°C to 750°C. The reason for this is that if the temperature becomes low, hydrates remain and it is difficult to control the amount added in the next step. If the temperature reaches high temperature, fluorine gas significantly volatilizes and easily reacts with Al or Si components of furnace materials, saggers, etc. In addition, if the roasting is performed at a low temperature, the roasted product will not agglomerate, and powder can be obtained without pulverizing. However, if the roasted product is roasted at a temperature exceeding 800°C, the roasted product will easily solidify, and pulverization may be necessary. Regarding roasting, it is preferable to use one of an electric furnace, a roller kiln, a rotary kiln, or the like. For the baking, either an active atmosphere such as an atmospheric atmosphere or an inert atmosphere such as argon gas may be used. However, in terms of obtaining a desired material composition or manufacturing cost, an atmospheric atmosphere is preferred. From the viewpoint of obtaining a desired material composition and suppressing the mixing of Al or Al and Si, the baking time is preferably, for example, 3 to 48 hours, and particularly preferably 5 to 24 hours.

[Step 3] In this step, the rare earth fluoride obtained in the second step is mixed with oxides of rare earth elements and/or compounds of rare earth elements that will become oxides after being roasted in the atmosphere, and then roasted to obtain REaObFc The rare earth oxyfluoride or the mixture of the rare earth oxyfluoride and the rare earth fluoride. As compounds of rare earth elements that become oxides after being baked in the atmosphere, hydroxides of rare earth elements, carbonates of rare earth elements, warm acetates of rare earth elements, oxalates of rare earth elements, or various other compounds can be used. Rare earth complexes, etc. As compounds of rare earth elements mixed with rare earth fluoride in this step, oxides of rare earth elements that are less likely to generate gas components cause less damage to the furnace material and can reduce Al or Si or other impurities, so they are more reliable. good.

Furthermore, a mixture of a rare earth oxyfluoride and a rare earth fluoride is called a mixture because both the peaks of the rare earth oxyfluoride and the peaks of the rare earth fluoride are observed in powder X-ray diffraction.

Before mixing, the rare earth fluoride or rare earth element compound may also be pulverized to a particle size that is easy to handle if necessary. Mixing can be performed using various dry grinders, wet grinders, mixers or mixing methods.

The mixing ratio of rare earth fluorides and rare earth oxides and/or compounds that become oxides after being baked in the atmosphere is preferably the F/RE molar ratio (hereinafter, also referred to as "Molecular Ratio") to the target material for sintered bodies. molar ratio 1"), or slightly larger than the F/RE molar ratio of the target sintered body material, taking into account that F is slightly volatilized due to baking. For example, in order to obtain a desired composition or to prevent the mixing of Al and Si, the mixing ratio of rare earth fluorides and rare earth oxides and/or compounds that become oxides after being baked in the atmosphere is F/ The RE molar ratio (hereinafter, also referred to as "molar ratio 2") is preferably molar ratio 2/molar ratio 1 of 0.95 to 1.10, particularly preferably 1.00 to 1.05.

In the baking after mixing, an example of an environment in which the Al mixed in the material is below the above-mentioned specific value is to use an oxidizer as a furnace material, a sagger, or a dish that is in direct contact with the mixture in the same manner as in the second step. Materials such as yttrium (Y ₂ O ₃ ), zirconium oxide (ZrO ₂ ) or platinum (Pt) that do not contain Al or Si components as much as possible. Regarding the calcination temperature, it is preferably 500°C to 900°C, more preferably 550°C to 850°C, and even more preferably 600°C to 800°C. The reason for this is that when the temperature is low, the rare earth oxyfluoride is insufficiently produced, and when the temperature is high, the hydrogen fluoride gas significantly volatilizes. For roasting, either an active atmosphere such as an atmospheric atmosphere or an inert atmosphere such as argon gas can be used. However, in terms of obtaining a desired composition and manufacturing cost, an atmospheric atmosphere is preferred. From the viewpoint of obtaining a desired material composition and suppressing the mixing of Al or Al and Si, the baking time is preferably, for example, 3 to 24 hours, and particularly preferably 5 to 12 hours.

In addition, in the case of this method, the amounts of Al and Si are usually not less than the above-mentioned lower limits. The reason is considered to be that Al or Si originally contained in the raw materials or a part of Al or Si contained in the raw materials of the manufacturing equipment.

[Step 4] In this step, the rare earth oxyfluoride represented by REaObFc or the mixture of the rare earth oxyfluoride and the rare earth fluoride is crushed to obtain the rare earth oxyfluoride represented by REaObFc or the rare earth oxyfluoride. A slurry of a mixture of oxyfluorides and rare earth fluorides. For grinding, either dry grinding or wet grinding can be used. The crushing may be carried out in one stage, or may be carried out in two or more stages. In terms of cost and labor, it is better to crush in one stage. It is preferable to add a liquid medium such as water after grinding to form a slurry. In the case of dry grinding, various dry grinders such as attritors, jet mills, ball mills, hammer mills, and pin mills can be used. On the other hand, when performing wet grinding, various wet grinders such as a ball mill and a bead mill can be used. The parts of the pulverizer that are in contact with the object to be pulverized (such as the pulverizing medium and the inner surface of the device) should be made as free of Al as possible, especially Al and Si. For example, stainless steel can be used for the inner surface of the device (however, when it is only referred to as "stainless steel" below, except for those with Al added such as SUS405 and SUS631), zirconium oxide, yttria-stabilized zirconia (YSZ) (and further Or, yttria-stabilized zirconia (YSZ) is used in the sense that it also includes yttria-stabilized zirconia), or general-purpose plastics, etc. In addition, as the grinding medium, stainless steel, zirconia, YSZ, resin-coated beads, etc. can be used. The grinding degree of the rare earth oxyfluoride or the mixture of rare earth oxyfluoride and rare earth fluoride in this step is preferably the BET specific surface area (BET) measured using the BET single-point method after drying the pulverized slurry. ) becomes about 2 m ² /g～10 m ² /g. By carrying out this level of grinding, it is easy to obtain particles that have pore peaks and a preferable pore volume within a preferable pore range, and have a BET specific surface area within a preferable range. From these viewpoints, the BET specific surface area (BET) is further preferably 3 m ² /g to 8 m ² /g.

Preferably, the compound concentration of the rare earth oxyfluoride or the mixture of the rare earth oxyfluoride and the rare earth fluoride in this step is set to 100 g/L to 1500 g/L, particularly preferably 300 g/L. ~1000 g/L. By setting the slurry concentration within this range, excessive energy consumption can be suppressed, and the slurry viscosity can be made appropriate to stabilize the spray. In the step of adjusting the slurry concentration, various additives such as binders, plasticizers or dispersants can be added as needed. When adding additives at this time, from the viewpoint of easy removal of organic matter when the molded body is baked in the next step, it is preferable to set the total amount of organic matter to 10 mass % or less. As for the organic substance used as the binder, polyvinyl alcohol, polyvinyl butyral, methyl cellulose, carboxymethyl cellulose, acrylic binders containing carboxyl groups or their derivatives in the molecule, polyethylene glycol, Polyvinylpyrrolidone and other organic polymer adhesives.

[Step 5] In this step, the slurry obtained in step 4 is granulated using a spray dryer to obtain the rare earth oxyfluoride represented by REaObFc or the rare earth oxyfluoride and the rare earth fluoride. The mixture is granulated. When the spray dryer is running, the rotation speed of the atomizer is preferably set to 5000 min ^-1 ~ 25000 min ^-1 . By setting the rotation speed to 5000 min ^-1 or more, uniform granules can be obtained. On the other hand, by setting the rotation speed to 25000 min ^-1 or less, it is easy to obtain particles with a desired particle size or better fluidity. From these viewpoints, the rotation speed of the atomizer is preferably set to 6000 min ^-1 to 20000 min ^-1 . When the spray dryer is operating, the inlet temperature is preferably set to 150°C to 300°C. By setting the inlet temperature to 150°C or higher, the solid content can be sufficiently dried and particles with less residual moisture can be easily obtained. On the other hand, by setting the inlet temperature to 300°C or less, energy wasted can be suppressed. The parts of the spray dryer that are in contact with the slurry are preferably made of components containing as little Al as possible, especially Al and Si. Examples of such a member include stainless steel and Teflon (registered trademark).

Through the above steps, a material for sintered bodies is obtained.

Next, the sintered body of the present invention will be described. The sintered body of the present invention contains REaObFc, The ratio of the molar number of fluorine element (F) to the molar number of rare earth elements (RE) (F/RE molar ratio) in the entire sintered body is 1.3 or more and 2.8 or less, and The content of aluminum (Al) is 50 ppm by mass or less. The sintered body of the present invention exhibits excellent corrosion resistance against plasma or chemical liquid due to the above-mentioned constitution.

As the preferred REaObFc constituting the sintered body, the description regarding the preferred configuration of REaObFc as the material for the sintered body described above can be applied.

In order to further improve the excellent corrosion resistance of the sintered body in plasma and chemical liquids, the F/RE molar ratio of the sintered body is preferably 1.3 or more and 2.8 or less, more preferably 1.4 or more and 2.6 or less, especially The best value is above 1.5 and below 2.4. The F/RE molar ratio of the sintered body can be measured by the method described in the following examples.

By setting the Al content in the sintered body to 50 ppm by mass or less, heterogeneous phases or large impurity grain boundaries caused by Al can be suppressed, resulting in excellent corrosion resistance against plasma or chemical liquid treatment. In addition, by setting the Al content in the sintered body to 1 mass ppm or more, it not only facilitates production, but also has the advantage of improving mechanical strength. In this regard, the Al content in the material for sintered bodies is more preferably from 1 mass ppm to 35 mass ppm, and particularly preferably from 1 mass ppm to 25 mass ppm. The Al content of the sintered body can be measured by the method described in the following examples.

Furthermore, by setting the Si content in the sintered body to 500 ppm by mass or less, heterogeneous phases or large impurity grain boundaries caused by Al can be suppressed, so the corrosion resistance against plasma or chemical liquid treatment is excellent. In addition, by setting the Si content in the sintered body to 1 mass ppm or more, it is easy to manufacture and has the advantage of improving the mechanical strength. In this regard, the Si content in the material for sintered bodies is more preferably 1 mass ppm or more and 350 mass ppm or less, and particularly preferably 1 mass ppm or more and 200 mass ppm or less. The Si content of the sintered body can be measured by the method described in the following examples.

The sintered body of the present invention is preferably one in which the crystalline phase other than the oxyfluoride of the rare earth element is substantially composed only of the fluoride of the rare earth element represented by REF ₃ in the XRD analysis. Preferably, it is substantially composed of only fluorides of rare earth elements represented by REF ₃ , which means that in XRD analysis using CuKα line and 2θ = 20 to 60° as the scanning range, it originates from fluorine oxidation of rare earth elements. The height of the maximum height peak (main peak) of the crystalline phase of the compound other than the fluoride of the rare earth element represented by REF ₃ is 10 relative to the peak height of the maximum height peak (main peak) of the crystalline phase derived from REaObFc % or less, more preferably 5% or less, still more preferably 3% or less, most preferably 1% or less.

Furthermore, in XRD analysis of the sintered body of the present invention (specifically, XRD analysis using CuKα line and 2θ=20 to 60° as the scanning range), fluorine derived from rare earth elements other than REaObFc was observed. In the case of an oxide peak, the peak height of the peak is preferably 10% or less, more preferably 5% or less relative to the peak height (main peak) of the maximum height of the crystal phase derived from REaObFc.

The sintered body of the present invention preferably uses REaObFc as the main phase. Here, using REaObFc as the main phase means that in XRD analysis using CuKα line and 2θ=20 to 60° as the scanning range, the peak originating from REaObFc is the peak with the maximum height.

Furthermore, even when the sintered body of the present invention does not have REaObFc as the main phase, the peak height of the main peak of REaObFc is relative to the peak height of the specific plane of the crystalline phase of the rare earth element fluoride REF ₃ represented by REF ₃ . The high ratio is preferably 50% or more, more preferably 80% or more. The peak of this specific surface is the same as the peak of the specific surface of the crystal phase of REF ₃ in the above-mentioned material for sintered body.

When the sintered body of the present invention contains REF ₃ , in order to obtain the above-mentioned effect of containing REF ₃ , the height ratio of the main peak of REF ₃ to the height of the main peak of REaObFc is preferably 1% or more, more preferably It is 5% or more, and it is more preferable that it is 10% or more.

The sintered body of the present invention is dense and has a relatively high density. By producing a sintered body with a relatively high density, the barrier properties of corrosive gases such as halogen-based corrosive gases can be increased. The sintered body of the present invention has high density and excellent corrosive gas barrier properties. Therefore, when it is used as a component of a semiconductor device, for example, it can prevent corrosive gas or chemical liquid from flowing into the component. Therefore, the sintered body of the present invention has higher anti-corrosion performance in corrosive gas or chemical liquid. Such a member with a high barrier property to etching gas is suitable for, for example, a vacuum chamber component of an etching apparatus, an etching gas supply port, a focus ring, a wafer holder, and the like. In addition, it has high barrier properties against chemical liquids and is suitable for wet etching of containers and other components. From the viewpoint of making the sintered body of the present invention denser, the relative density of the sintered body is preferably 90% or more, more preferably 95% or more, and particularly preferably 98% or more. Relative density can be measured by the following method.

Furthermore, from the viewpoint of improving corrosion resistance, the smaller the porosity, especially the open porosity (OP), the better. The open porosity is preferably 1 mass% or less, further preferably 0.5 mass% or less, and particularly preferably 0.3 mass% or less. Porosity (open porosity) can be measured by the following method.

A sintered body having the above relative density and open porosity (OP) can be obtained by adjusting the temperature conditions or pressure conditions when manufacturing the sintered body of the present invention by the following preferred manufacturing method.

The inventor's sintered body is dense and has high hardness, which can more effectively prevent corrosive gases or chemical liquids from flowing into the interior of the component, and has excellent corrosion resistance in plasmas and chemical liquids such as halogen-based plasmas. Specifically, in the sintered body of the present invention, the Vickers hardness is preferably 3 GPa or more, more preferably 4 GPa or more. In addition, the larger the Vickers hardness is, the better. However, from the viewpoint of ease of manufacturing the sintered body, it is more preferably 8 GPa or less, and further more preferably 7 GPa or less. Vickers hardness can be measured by the method described in the following examples.

The sintered body of the present invention has a specific composition and is corrosion-resistant to plasma or chemical liquids. Therefore, it is suitable for use as a plasma-resistant member formed from the sintered body on a surface exposed to plasma, or in contact with chemical liquids in wet etching. A liquid-resistant component whose surface is formed from the sintered body.

Plasma-resistant components are preferably components exposed to plasma in the presence of halogen-based corrosive gases such as fluorine-based and chlorine-based gases used in plasma processing processes for semiconductors, and may also be referred to as components for plasma processing equipment. Specific examples of the plasma-resistant member include those used in a chamber such as a vacuum chamber in a plasma etching apparatus or within the chamber. Examples of plasma-resistant members used inside the chamber include focusing rings, shower heads, electrostatic chucks, top plates, or gas nozzles used when plasma etching substrates during semiconductor device manufacturing steps. . As halogen-based corrosive gases, fluorine-based gases such as SF ₆ , CF ₄ , CHF ₃ , ClF ₃ , and HF, chlorine-based gases such as Cl ₂ , HCl, and BCl ₃ , and bromine-based gases such as Br ₂ , HBr, and BBr ₃ are known. and iodine-based gases, etc., but are not limited thereto.

The liquid-resistant member is preferably a member such as a container used in wet etching during semiconductor manufacturing that comes into contact with the chemical liquid for wet etching. As a chemical liquid for wet etching, there are halogen-based or non-halogen-based liquids such as hydrofluoric acid and hydrochloric acid. In addition, an acid-based liquid or an acrylic-based liquid is used. In the present invention, any one can be used. However, for halogen The liquid medicine is particularly effective.

The sintered body of the present invention can be used not only inside semiconductor manufacturing equipment or as a component thereof, but also as a component of various plasma processing equipment and chemical equipment.

The sintered body of the present invention can be suitably obtained by sintering the material for sintered bodies of the present invention. In the above-mentioned sintering step, a press machine, a baking furnace, etc. are used to shape and sinter the material for the sintered body. In this step, the forming step and the sintering step can be performed separately, or pressure sintering can be used to simultaneously perform at least part of the forming step and the sintering step. An example of the case where at least a part of the shaping step and the sintering step are performed simultaneously is a case where the material for the sintered body is molded and then pressure-sintered. In addition, there are cases where two-stage molding steps are combined, such as combined mold forming and uniform pressure forming (CIP), or two or more stages of sintering steps, such as combination of normal pressure sintering and pressure sintering, are sometimes performed.

In this production method, as the molding step of the raw material powder, a mold pressing method, a rubber pressing (equal pressure pressing) method, a sheet forming method, an extrusion forming method, a slurry forming method, etc. can be used. Sintering after forming can be combined with one or more of various sintering methods such as non-pressure sintering, gas pressure sintering, hot equalizing pressure (HIP), hot pressing (HP) or pulsed power pressing (SPS). use. Furthermore, various "forming methods" are sometimes described as "forming methods."

Among the above-mentioned sintering methods, in terms of obtaining a dense and high-hardness sintered body with excellent chemical resistance and plasma resistance, the gas pressure sintering method, hot equalizing pressure (HIP), and Pressure sintering methods such as hot pressing (HP) or pulsed power pressing (SPS). A suitable pressure for pressure sintering is 10 to 100 MPa, and a suitable temperature is 700 to 1100°C. When the non-pressure sintering method is used, as a forming step, although it is not like the pressure sintering method, it is possible to obtain a very dense and hard sintered body with excellent chemical resistance and plasma resistance. Specifically, it is preferable to perform primary molding by a mold pressurizing method, and then perform secondary molding by a rubber pressurizing method. The preferred pressure for the mold pressurizing method is 10 to 100 MPa, the preferred pressurizing pressure for the rubber pressurizing method is 50 to 300 MPa, and the preferred temperature for normal pressure sintering is 1000 to 1600°C. Furthermore, the members that come into contact with the material for the sintered body during molding and sintering, such as the forming mold, the baking mold, the punch, the die nozzle, the backing plate, and the powder coating, are not used to contain Al, especially Al and Si. Examples of usable materials include stainless steel, carbon, yttrium oxide, and rubber. The sintering atmosphere is preferably an inert atmosphere such as argon or nitrogen or a vacuum atmosphere. In addition, the so-called vacuum atmosphere refers to an atmosphere in which the pressure is 10 ⁵ Pa or less in terms of absolute pressure. Example

Hereinafter, the present invention will be further described in detail through examples. However, the scope of the present invention is not limited to this embodiment.

(Example 1) [Step 1] To 200 L of yttrium oxide (Y ₂ O ₃ ), 25 kg of yttrium nitrate aqueous solution was added dropwise to 26.6 kg of 50 mass% hydrofluoric acid to obtain a precipitation of the yttrium fluoride precursor. things. The obtained precipitate is repulped and washed, and then filtered using a centrifuge to obtain a filter cake of the yttrium fluoride precursor. [Step 2] Put an appropriate amount of the filter cake obtained in the first step into an yttrium oxide sagger, and bake it in an electric furnace at 650°C for 24 hours in the air to obtain yttrium fluoride (YF ₃ ) powder. Furthermore, the obtained yttrium fluoride powder was used as the yttrium fluoride raw material in Examples 1 to 5. [Step 3] Mix 1.06 kg of yttrium fluoride powder obtained in step 2 and 0.94 kg of yttrium oxide (Y ₂ O ₃ ) powder, put them into a yttrium oxide sagger, and use an electric furnace in the atmosphere Calculate at 650°C for 5 hours to obtain yttrium oxyfluoride powder. [Step 4] Mix the yttrium oxyfluoride powder obtained in step 3 with pure water, and use a bead mill (material of beads: YSZ; material of the inner surface of the grinding device: polypropylene) to form the powder in Table 1 The BET specific surface area is reported in the method for crushing. After grinding, pure water was added to prepare a 500 g/L yttrium oxyfluoride slurry. The BET specific surface area was measured by taking a part of the slurry during the grinding process, drying it, and using the same method as the material for sintered bodies described below. [Step 5] Use a spray dryer (manufactured by Okawara Processing Machine Co., Ltd.) (material of the inner surface of the device: stainless steel) to granulate and dry the slurry obtained in step 4 to obtain yttrium oxyfluoride particles and sinter them Body materials. The operating conditions of the spray dryer are as follows.・Slurry supply speed: 75 mL/min ・Atomizer rotation speed: 12500 rpm ・Inlet temperature: 250℃ [Step 6] For 5 g of the granular sintered body material obtained in step 5, use Sinterland stock The pulse current pressing device manufactured by the company (material of die nozzle: carbon; material of punch: carbon) is pressure-sintered at 30 MPa and 850°C in a vacuum atmosphere to obtain φ20 mm×4 mmt fluorine oxidation Yttrium sintered body.

(Example 2) In the same manner as in Example 1, except that the amounts of yttrium fluoride powder and yttrium oxide powder used for mixing in the third step of Example 1 are changed to 1.25 kg of yttrium fluoride powder and 0.75 kg of yttrium oxide powder. , to obtain particles of a mixture of yttrium oxyfluoride and yttrium fluoride, which are materials for sintered bodies and their sintered bodies.

(Example 3) In the same manner as in Example 1, except that the amounts of yttrium fluoride powder and yttrium oxide powder used for mixing in the third step of Example 1 are changed to 1.44 kg of yttrium fluoride powder and 0.56 kg of yttrium oxide powder. , to obtain particles of a mixture of yttrium oxyfluoride and yttrium fluoride, which are materials for sintered bodies and their sintered bodies.

(Example 4) In the same manner as in Example 1, except that the amounts of yttrium fluoride powder and yttrium oxide powder used for mixing in the third step of Example 1 were changed to 1.62 kg of yttrium fluoride powder and 0.38 kg of yttrium oxide powder. , to obtain particles of a mixture of yttrium oxyfluoride and yttrium fluoride, which are materials for sintered bodies and their sintered bodies.

(Example 5) In the same manner as in Example 1, except that the amounts of yttrium fluoride powder and yttrium oxide powder used for mixing in the third step of Example 1 were changed to 1.81 kg of yttrium fluoride powder and 0.19 kg of yttrium oxide powder. , to obtain particles of a mixture of yttrium oxyfluoride and yttrium fluoride, which are materials for sintered bodies and their sintered bodies.

(Example 6) In the same manner as in Example 1, except that the baking temperature in the second step of Example 1 was changed from 650°C to 750°C, yttrium oxyfluoride particles, that is, a sintered body material and a sintered body thereof were obtained.

(Example 7) In the second step of Example 1, the calcining temperature was changed from 650°C to 850°C, and in the fourth step, a total amount of 4% by mass of an organic binder was added to the slurry. 1 In the same manner, yttrium oxyfluoride particles, which are materials for sintered bodies, are obtained. Furthermore, the granular sintered body material obtained in step 5 was molded at a pressure of 49 MPa (material of the mold: stainless steel), and then uniformly pressure molded at a pressure of 294 MPa (material of the mold: rubber). The obtained molded body was baked at 1500°C for 2 hours in an argon atmosphere (the material of the backing plate for baking: yttrium oxide), instead of the pressure sintering using a pulse current pressing device in the sixth step above. , in the same manner as in Example 1, a sintered body of yttrium oxyfluoride was obtained.

(Example 8) The calcining temperature in the second step of Example 7 was changed to 550°C, and the amounts of yttrium fluoride powder and yttrium oxide powder used for mixing in the third step were changed to 1.15 kg of yttrium fluoride powder and 0.85 kg of yttrium oxide. powder, and the atomizer rotation speed in step 5 is changed to 20000 rpm. In addition, in the same manner as in Example 7, particles of a mixture of yttrium oxyfluoride and yttrium fluoride, that is, a sintered body material and its sintering are obtained. body.

(Example 9) The material for the granular sintered body obtained in step 5 is pressure-sintered using hot pressing (HP) in an argon atmosphere at 20 MPa and 920°C (material of punch: carbon; material of die nozzle: carbon ) in place of the pressure sintering using a pulse current pressing device in step 6 of Example 3, except that in the same manner as in Example 3, particles of a mixture of yttrium oxyfluoride and yttrium fluoride, that is, a sintered body were obtained materials and their sintered bodies.

(Example 10) The rare earth element (RE) in Example 1 was changed from yttrium (Y) to lanthanum (La). In the first step, 2.5 kg of nitric acid was converted into 20 L of lanthanum oxide (La ₂ O ₃ ). 1.8 kg of 50 mass% hydrofluoric acid was added dropwise to the lanthanum aqueous solution to obtain a precipitate of the lanthanum fluoride precursor, thereby obtaining lanthanum fluoride (LaF ₃ ) powder in the second step. Furthermore, regarding the mixing in the third step, 1.73 kg of the lanthanum fluoride powder obtained in the second step and 0.27 kg of the lanthanum oxide (La ₂ O ₃ ) powder were mixed. Except for these operations, in the same manner as in Example 1, particles of a mixture of lanthanum oxyfluoride and lanthanum fluoride, that is, a material for a sintered body and a sintered body thereof were obtained.

(Example 11) The rare earth element in Example 1 was changed from yttrium to gallium (Gd), and in the first step, 3.3 ml of gallium nitrate aqueous solution converted into 5 kg of 40 L of gallium oxide (Gd ₂ O ₃ ) was added dropwise. kg of 50 mass% hydrofluoric acid to obtain a precipitate of the gallium fluoride precursor, thereby obtaining gallium fluoride powder in the second step. Furthermore, regarding the mixing in the third step, 1.09 kg of the gallium fluoride (GdF ₃ ) powder obtained in the second step and 0.91 kg of the gallium oxide (Gd ₂ O ₃ ) powder were mixed. Except for these operations, in the same manner as in Example 1, particles of a mixture of gallium oxyfluoride and gallium fluoride, that is, a sintered body material and a sintered body thereof were obtained.

(Example 12) Regarding the mixing in the third step of Example 11, 1.55 kg of the gallium fluoride powder obtained in the second step and 0.45 kg of the gallium oxide powder were mixed, in the same manner as in Example 11, The particles of the mixture of gallium oxyfluoride and gallium fluoride are obtained, which are the material for the sintered body and the sintered body thereof.

(Example 13) The rare earth element in Example 1 was changed from yttrium to erbium (Er). In the first step, 1.6 erbium nitrate aqueous solution was added dropwise to 20 L of erbium oxide (Er ₂ O ₃ ) to convert 2.5 kg of erbium nitrate aqueous solution. kg of 50 mass% hydrofluoric acid to obtain a precipitate of the erbium fluoride precursor, thereby obtaining erbium fluoride (ErF ₃ ) powder in the second step. Furthermore, regarding the mixing in the third step, 1.36 kg of the erbium fluoride powder obtained in the second step and 0.64 kg of the erbium oxide (Er ₂ O ₃ ) powder were mixed. Except for these operations, in the same manner as in Example 1, particles of a mixture of erbium oxyfluoride and erbium fluoride, that is, a material for a sintered body and a sintered body thereof were obtained.

(Example 14) The rare earth element in Example 1 was changed from yttrium to ytterbium (Yb). In the first step, 3 drops of 3 kg of ytterbium nitrate aqueous solution was added to 40 L of ytterbium oxide (Yb ₂ O ₃ ) to convert 5 kg of ytterbium nitrate aqueous solution. kg of 50 mass% hydrofluoric acid to obtain a precipitate of the ytterbium fluoride precursor, thereby obtaining ytterbium fluoride powder in the second step. Furthermore, regarding the mixing in the third step, 1.01 kg of the ytterbium fluoride (YbF ₃ ) powder obtained in the second step and 0.99 kg of the ytterbium oxide (Yb ₂ O ₃ ) powder were mixed. Except for these operations, in the same manner as in Example 1, ytterbium oxyfluoride particles, that is, a material for a sintered body and a sintered body thereof were obtained.

(Example 15) Regarding the mixing in the third step of Example 14, 1.84 kg of the ytterbium fluoride powder obtained in the second step and 0.16 kg of the ytterbium oxide powder were mixed. Otherwise, in the same manner as in Example 14, The particles of the mixture of ytterbium oxyfluoride and ytterbium fluoride are obtained, which are the material for the sintered body and the sintered body thereof.

(Example 16) The rare earth element in Example 1 was changed from yttrium to phosphorus (Lu). In the first step, 1.5 kg of phosphorus nitrate aqueous solution was added dropwise to 20 L of phosphorus oxide (Lu ₂ O ₃ ) to 2.5 kg. kg of 50 mass% hydrofluoric acid to obtain a precipitate of the phosphonium fluoride precursor, thereby obtaining phosphonium fluoride (LuF ₃ ) powder in the second step. Furthermore, regarding the mixing in the third step, the same procedure as in Example 1 was performed except that 1.01 kg of the phosphorus fluoride powder obtained in the second step and 0.99 kg of the phosphorus oxide (Lu ₂ O ₃ ) powder were mixed. In the same manner, particles of a mixture of phosphorus oxyfluoride and phosphorus fluoride, that is, a sintered body material and its sintered body are obtained.

(Comparative Example 1) It was produced using the production method of Example 6 described in Patent Document 3. (1) Step A: Mix fine powder yttrium oxide (Y ₂ O ₃ ) (D _*50D : 0.24 μm; carbon: 0.1 mass%) manufactured by Japan Yttrium Company and yttrium fluoride (YF ₃ ) manufactured by Japan Yttrium Company (D _*50D : 7.4 μm; carbon: 0.05% by mass) was mixed at a molar ratio of LnF ₃ /Ln = 0.55. (2) Step B: Roasting The mixture obtained in step A was put into an alumina dish, and roasted at 950° C. for 8 hours using an electric furnace in the air. (3) Step C: Crushing. The roasted product obtained in step B is dry-pulverized using an atomizer (material inside the device: alumina), and then mixed with pure water of the same mass. By using a 0.8 mm diameter atomizer, Yttria-stabilized zirconia (YSZ) balls were crushed in a bead mill (material of the inner surface of the device: zirconia-reinforced alumina) for 4 hours. Thereafter, the wet grinding slurry was obtained by grinding for 3 hours using a bead mill with yttria-stabilized zirconia (YSZ) balls with a diameter of 0.4 mm (material inside the device: zirconia-reinforced alumina). (4) Step D: Spray drying Add an acrylic binder and pure water to the wet grinding slurry obtained in step C, and mix so that the slurry concentration becomes 1000 g/L. The amount of powder contained in was set to 3.5% by mass. This slurry was spray-dried using a spray dryer (Ogawara Chemical Machinery Co., Ltd. (material of the inner surface of the device: stainless steel)) to obtain a granular sintered body material. The operating conditions of the spray dryer are as follows. ・Slurry supply Speed: 300 mL/min ・Atomizer rotation speed: 9000 min ^-1・Inlet temperature: 200℃ (5) Step E: For the material for the sintered body obtained in step D, mold the material for the sintered body obtained in step D at a pressure of 49 MPa (mold Material: stainless steel), then perform equalization molding at a pressure of 294 MPa (mold material: rubber). The obtained molded body is fired at 1500°C for 2 hours in an argon atmosphere (material of sintering backing plate: oxidized Yttrium), placed naturally in an electric furnace and cooled to 150°C to obtain a sintered body of yttrium oxyfluoride.

(Comparative Example 2) Steps A and B of Comparative Example 1 were not performed, and only yttrium fluoride (YF ₃ ) (D _*50D : 7.4 μm; carbon: 0.05 mass%) manufactured by Japan Yttrium Co., Ltd. was used for step C. A sintered body of yttrium fluoride was obtained in the same manner as in Comparative Example 1 except that the sintering temperature in step E was 1000°C.

(Comparative Example 3) Steps A and B of Comparative Example 1 were not performed, and only fine powder yttrium oxide (Y ₂ O ₃ ) (D _*50D : 0.24 μm; carbon: 0.1 mass%) manufactured by Japan Yttrium Co., Ltd. was used as C. A sintered body of yttrium oxide was obtained in the same manner as in Comparative Example 1 except that the atmosphere in step E was set to the atmospheric atmosphere and the sintering temperature was set to 1600°C.

(Comparative example 4) Put an appropriate amount of the filter cake of the yttrium fluoride precursor obtained in the first step of Example 1 into a mullite sagger, and use an electric furnace to bake it at 900°C for 24 hours in the air to obtain yttrium fluoride. block. Thereafter, the powder was pulverized using a stone mill to obtain yttrium fluoride powder. 1.72 kg of the obtained yttrium fluoride powder and 0.28 kg of yttrium oxide were mixed, put into a mullite sagger, and roasted at 900°C for 5 hours in an electric furnace in the air to obtain yttrium oxyfluoride powder. 5 g of the obtained powder was processed in a vacuum atmosphere at 30 MPa and 850°C using a pulse current pressurizing device manufactured by Sinterland Co., Ltd. (material of die nozzle: carbon; material of punch: carbon). Pressurize and sinter to obtain a φ20 mm×4 mmt yttrium oxyfluoride sintered body.

(Comparative example 5) In the same manner as in Example 3, except that the sagger used in the second step of Example 3 was made of mullite and the baking temperature and time of the second step were set to 900° C. and 24 hours, fluorine oxidation was obtained. Yttrium sintered body.

(Comparative example 6) In the 6th step, the particles obtained in the 5th step of Example 1 were put into a mullite sagger and roasted at 900° C. for 5 hours using an electric furnace in the air. In the same manner as in Example 1, a sintered body of yttrium oxyfluoride was obtained.

(measurement, evaluation) The obtained material for sintered bodies was measured for the items listed in Table 1 by the following method. The results are shown in Table 1.

＜Oxygen amount (mass %)＞ The mass % of oxygen was measured by melting in inert gas-infrared absorption method (in which halogen capture was used).

＜F/RE Molby＞ The F (fluorine) content of the material was measured by the XRF (X-Ray Fluorescence Analysis) method using the ZSX Primus II manufactured by Rigaku Corporation, and was converted into moles of rare earth elements per 1 kg of powder. Count. In addition, the RE (rare earth element) content of the material is measured by perchloric acid dissolution-ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry, inductively coupled plasma luminescence analysis) method to measure the mass % of rare earth elements and convert It is the number of moles of rare earth elements per 1 kg of powder. Based on the calculated F (fluorine) content and RE (rare earth element) content, the F/RE molar ratio is calculated.

<X-ray Diffraction Measurement of Material for Sintered Body> Furthermore, in order to remove organic matter, the material for sintered body obtained was baked at 550° C. for 2 hours in the air. The result obtained by the above operation was subjected to the following method and powdered X-ray diffraction measurements were performed by X-ray diffractometry. Table 1 shows the results of identifying the crystal phase. In addition, the X-ray diffraction peak intensity in Table 1 is the peak height ratio of the main peak derived from the crystal phase of each compound, and represents the value when the peak height of the main peak of 2θ=20° to 60° is set to 100. In each of the Examples and Comparative Examples, the peak height of the main peak of the crystal phase derived from compounds other than the oxyfluoride of rare earth elements and the fluoride of rare earth elements represented by REF ₃ is relative to the peak height of the crystal phase derived from REaObFc The peak height of the main peak is less than 1%. Among them, the difference in the main peak position in the PDF card is the implementation of the combination of Y ₅ O ₄ F ₇ and YF ₃ , Gd ₄ O ₃ F ₆ and GdF ₃ , Er ₅ O ₄ F ₇ and ErF ₃ within 2θ = 0.4°. Examples 1 to 9, 11 to 13, and Comparative Examples 4 to 6 respectively use the intensity ( _IS ) corresponding to the peak of the specific surface divided by the relative intensity of the specific surface (the intensity of the main peak is 100) (recorded in the PDF card) Intensity: _IT ) The value obtained is used as the intensity of the main peak (I _M ). Furthermore, baking at 550° C. for 2 hours in the air did not affect the composition of the materials for the sintered bodies in each of the examples and comparative examples. [X-ray diffraction measurement] ・Device: Ultima IV (manufactured by Rigaku Co., Ltd.) ・Line source: CuKα line ・Tube voltage: 40 kV ・Tube voltage: 40 mA ・Scan speed: 2 degrees/min ・Step change: 0.02 degrees・Scanning range: 2θ＝20°～60°

＜Measurement method of Al content＞ The Al content in the material was measured using SPS3520V-DD manufactured by Hitachi High-Tech Science Co., Ltd. and by perchloric acid dissolution-ICP-AES analysis method.

＜Measurement method of Si content＞ The Si content in the material was measured using a continuous flow analysis device (STAA-3) manufactured by BL-TEC Corporation and through acid dissolution, silicon tetrafluoride gasification separation, and silicomolybdic acid blue absorbance photometry.

＜Amount reduction on ignition＞ The material for the sintered body as the measurement sample was baked at 550° C. for 2 hours in the air, and then cooled by natural cooling in a desiccator (hereinafter, baking to cooling is referred to as "burning treatment"). The mass was measured before and after the burning treatment. Use the value of the following formula as the loss on ignition. Formula: (mass before burning treatment - mass after burning treatment)/mass before burning treatment × 100 (mass %)

<Hausner ratio> It is determined by Hausner ratio = tap density (g/cm ³ )/bulk density (g/cm ³ ). The multifunctional powder physical property tester Multitester MT-1001k (manufactured by Qingxin Enterprise Co., Ltd.) was used to measure the apparent bulk density TD (g/cm ³ ) of the tapping method and the apparent density AD (g/cm ³ ) of the standing method. , find its ratio. The measurement of apparent density TD (g/cm ³ ) by tap method is carried out in accordance with "7-1. Measurement method of tap density based on scraping constant weight method" in the installation instructions of the above-mentioned measuring instrument and in accordance with JIS Z 2512, static The apparent bulk density AD (g/cm ³ ) is measured according to "7-2. Measurement method of static bulk density (loosest filling bulk density)" in the installation instructions of the above-mentioned measuring device and in accordance with JIS K 5101-12- 1 to proceed.

＜BET specific surface area＞ The BET specific surface area was determined by the BET single-point method using Macsorb manufactured by Mountech Corporation as a measuring device. Use a mixed gas of 30% by volume of nitrogen and 70% by volume of helium as the measurement gas, and use pure nitrogen as the calibration gas.

＜Average particle size D50＞ The material for sintered body was put into the chamber of a sample circulator of Microtrac 3300EXII manufactured by Nikkiso Co., Ltd. filled with pure water until the appropriate concentration was determined by the determination device, and the measurement was performed.

<The first peak of pores, the second peak of pores, the pore volume of 0.05 μm or more and 0.5 μm or less, the pore volume of 5 μm or more and 50 μm or less> ・Device: AutoPore IV (manufactured by Micron Instruments Co., Ltd.) ・First pore peak: Generally, when the pore diameter distribution of particles including primary particles is measured, two peaks are obtained, and the peak on the small diameter side of the peaks is regarded as the first pore peak. ・The second wave peak of fine pores: The peak on the larger diameter side of the above-mentioned wave peaks is regarded as the second wave peak of fine pores. ・Pore volume of 0.05 μm or more and 0.5 μm or less: The cumulative value of the pore volume of pore diameters of 0.05 μm or more and 0.5 μm or less (pore volume 1 in Table 1) ・Pore volume of 5 μm or more and 50 μm or less: The cumulative value of the pore volume of pore diameters of 5 μm or more and 50 μm or less (pore second volume in Table 1)

[Table 1] Rare earth elements (RE) F/RE Morbi Powder physical properties Oxygen content [mass %] X-ray diffraction peak intensity Si content [mass ppm] Al content [mass ppm] Total amount of organic binder [mass %] Loss on ignition [mass %] Bulk density [g/cm ³ ] Tap density [g/cm ³ ] Hausnaby BET[m ² /g] Average particle size [μm] The first wave peak of pores [μm] Second wave peak of pores [μm] Pore 1st volume [mL/g] Second volume of pores [mL/g] RE-OF type RE-OF REF ₃ RE ₂ O ₃ Example 1 Y 1.4 10 Y ₅ O ₄ F ₇ 100 0 - 18 2 0 <1 1.5 1.7 1.1 6 48 0.10 12.9 0.17 0.27 Example 2 Y 1.7 8 Y ₅ O ₄ F ₇ 100 19 - 16 1 0 <1 1.4 1.6 1.1 5 45 0.12 11.3 0.15 0.24 Example 3 Y 2.1 6 Y ₅ O ₄ F ₇ 100 37 - 15 1 0 <1 1.5 1.6 1.1 5 46 0.13 11.3 0.15 0.25 Example 4 Y 2.3 4 Y ₅ O ₄ F ₇ 100 61 - 20 2 0 <1 1.5 1.7 1.1 5 38 0.12 10.1 0.14 0.25 Example 5 Y 2.7 2 Y ₅ O ₄ F ₇ 100 92 - 200 3 0 <1 1.5 1.8 1.2 5 47 0.13 12.0 0.14 0.23 Example 6 Y 1.4 10 Y ₅ O ₄ F ₇ 100 0 - 300 8 0 <1 1.4 1.6 1.1 4 47 0.18 12.9 0.11 0.26 Example 7 Y 1.5 10 Y ₅ O ₄ F ₇ 100 0 - 500 twenty three 4 5 1.4 1.6 1.1 4 42 0.17 11.3 0.12 0.28 Example 8 Y 1.6 9 Y ₅ O ₄ F ₇ 100 7 - 14 4 4 5 1.3 1.7 1.3 7 28 0.08 9.1 0.19 0.29 Example 9 Y 2.0 6 Y ₅ O ₄ F ₇ 100 38 - 17 3 0 <1 1.4 1.6 1.1 4 45 0.13 11.3 0.14 0.27 Example 10 La 2.5 2 La ₁₀ O ₇ F ₁₆ 100 72 - 300 7 0 <1 1.8 2.1 1.2 4 45 0.15 11.3 0.12 0.23 Example 11 Gd 1.5 6 Gd ₄ O ₃ F ₆ 100 4 - 32 2 0 <1 1.9 2.3 1.2 3 46 0.17 12.0 0.16 0.25 Example 12 Gd 2.2 3 Gd ₄ O ₃ F ₆ 100 43 - 400 9 0 <1 2.0 2.2 1.1 3 47 0.20 12.9 0.13 0.26 Example 13 Er 2.0 4 Er ₅ O ₄ F ₇ 100 31 - 50 5 0 <1 2.1 2.4 1.1 3 46 0.18 11.3 0.14 0.30 Example 14 yb 1.4 6 Yb ₅ O ₄ F ₇ 100 0 - 38 1 0 <1 2.2 2.3 1.0 4 47 0.10 12.9 0.18 0.26 Example 15 yb 2.7 1 Yb ₅ O ₄ F ₇ 92 100 - 500 8 0 <1 1.9 2.4 1.3 2 48 0.35 13.9 0.12 0.31 Example 16 Lu 1.7 5 Lu ₇ O ₆ F ₉ 100 twenty two - 27 2 0 <1 2.2 2.5 1.1 3 46 0.21 12.0 0.16 0.25 Comparative example 1 Y 1.0 13 YOF 100 0 - 2200 150 4 4 1.6 1.7 1.1 6 49 0.08 13.9 0.17 0.24 Comparative example 2 Y 3.0 - YF ₃ - 100 - 5800 380 4 5 1.7 1.8 1.1 5 45 0.10 12.9 0.14 0.22 Comparative example 3 Y - - Y ₂ O ₃ - - 100 10 1 4 4 1.4 1.5 1.1 10 48 0.18 11.3 0.16 0.29 Comparative example 4 Y 2.5 3 Y ₅ O ₄ F ₇ 100 79 - 4500 280 4 4 0.8 1.5 1.9 2 4 1.37 - 0.01 - Comparative example 5 Y 2.0 6 Y ₅ O ₄ F ₇ 100 35 - 3200 200 0 <1 1.6 1.8 1.1 4 46 0.18 12.9 0.10 0.27 Comparative example 6 Y 1.4 10 Y ₅ O ₄ F ₇ 100 0 - 1000 74 0 <1 1.5 1.9 1.3 1 48 0.73 15.0 0.03 0.30

The sintered bodies of each Example and Comparative Example obtained by the above method were subjected to XRF and XRD measurements in the same manner as for the materials for sintered bodies, and the composition ratio and F/RE molar ratio were determined. However, the sintered body is not pulverized and used for XRF and XRD measurements. In addition, in the XRD measurement of the sintered body, the pretreatment of baking at 550°C was not performed. In the XRD measurement of the sintered bodies of each Example and Comparative Example, the peak height of the main peak derived from the crystal phase of compounds other than oxyfluorides of rare earth elements and fluorides of rare earth elements represented by REF ₃ was relative to The peak height of the main peak derived from the crystalline phase of REaObFc is 1% or less. In addition, a part of the sintered body was thoroughly pulverized in a stainless steel mortar, and the Al content and Si content were determined by the same method as the above-mentioned sintered body material. Furthermore, the relative density, porosity, and Vickers hardness were determined by the following method. In addition, the following methods are used for immersion testing and plasma testing (measurement of etching rate). The results are shown in Table 2.

<Relative Density (%) and Porosity> The sintered body was placed in distilled water and kept under reduced pressure with a diaphragm vacuum pump for 1 hour, and then the weight W ₂ [g] in the water was measured. Furthermore, excess water was removed with a damp cloth, and the saturated weight W ₃ [g] was measured. Thereafter, the sintered body was placed in a desiccator and dried sufficiently, and then the dry weight W ₁ [g] was measured. The bulk density ρ _b [g/cm ³ ] and the open porosity OP are calculated from the following formula. ρ _b =W ₁ /(W ₃ -W ₂ )×ρ ₁ (g/cm ³ ) OP=(W ₃ -W ₁ )/(W ₃ -W ₂ )×100 (mass %) Here, ρ ₁ [g/cm ³ ] is the density of distilled water. Using the obtained bulk density ρ _b and theoretical density ρ _c [g/cm ³ ], the relative density (RD) [%] was calculated by the following formula. RD＝ρ _b /ρ _c ×100 (%) In addition, in Table 2, the relative density "ND" means that there is no density in the ICDD (International Center for Diffraction Data, International Center for Diffraction Data) which is the XRD powder analysis database. There is card information and the theoretical density is unclear, so the relative density cannot be calculated.

<Vickers Hardness> After rough grinding the sintered body, use a diamond slurry with an average particle size of 0.05 μm to grind it. Using this sample, the Vickers hardness was measured based on JIS R1610. Vickers hardness tester MVK-G1 (Akashi Seisakusho Co., Ltd.) was used for measurement. Regarding the conditions of the Vickers hardness test, use a load that can obtain an indentation along the provisions of 4.6.11 of JIS R1610 under a load of 100 gf (0.980665 N), hold for 15 seconds, measure 10 points, and calculate the average value. Observe the indentation through an optical microscope and measure the indentation size. Vickers hardness HV is calculated by the following formula. HV=(0.1891F)/d ² Here, F is the test load [N], and d is the average value of the diagonal length of the indentation [mm].

＜Immersion test＞ After processing the sintered body in a single-sided mirror-polished state of φ20 mm A container made of propylene was immersed in this solution at normal temperature for 1 week, and the weight reduction rate and the surface roughness of the polished surface were measured and evaluated. Those that satisfy both the following evaluation criteria (i) and (ii) are rated as ○ (better tolerance), and those that satisfy either of the following evaluation criteria (i) or (ii) are rated as △( Average tolerance), and those that do not satisfy both the following evaluation criteria (i) and (ii) are rated as × (poor tolerance). In addition, the evaluation criteria are: (i) the weight reduction rate is 0.5% or less, (ii) the increase in surface roughness of the polished surface is 20 nm or less. In addition, Ra (arithmetic mean roughness) was measured using a stylus type surface roughness measuring instrument (JIS B0651: 2001).

＜Plasma test＞ After processing the sintered body in a single-sided mirror-polished state of ϕ20 mm × 2 mmt (Ra is 10 nm or less), attach Kapton tape to half of the sintered body, with the mirror surface facing up. The status download was placed in the chamber of an etching device (RIE-10NR manufactured by SAMCO), and plasma etching was performed. Plasma etching conditions are as follows. Regarding the measurement of the etching rate, the step difference between the plasma-exposed surface and the non-exposed surface from which the tape was peeled off after plasma irradiation was measured by the above-mentioned surface roughness measurement. The measurement points are three points on each side of the sintered body, and the average value of the three points is calculated.・Ambient gas: CF ₄ /O ₂ /Ar＝40/20/40 (cc/min) ・High frequency power: RF (Radio Frequency) is 300 W ・Pressure: 5 Pa ・Etching time: 15 hours

[Table 2] Rare earth elements (RE) sintering method Sintered body physical properties Tolerance evaluation F/RE molar ratio of sintered body X-ray diffraction peak intensity Si content [mass ppm] Al content [mass ppm] Relative density[%] Porosity [mass %] Vickers hardness [GPa] Dip test Plasma test RE-OF type RE-OF REF ₃ RE ₂ O ₃ HF tolerance HCl tolerance Etching rate [nm/h] Example 1 Y SPS 1.4 Y ₅ O ₄ F ₇ 100 0 - 13 2 100 0.0 3 ○ ○ 3.0 Example 2 Y SPS 1.7 Y ₅ O ₄ F ₇ 100 10 - 13 1 99 0.0 5 ○ ○ 2.7 Example 3 Y SPS 2.0 Y ₅ O ₄ F ₇ 100 twenty one - 12 2 100 0.0 6 ○ ○ 2.6 Example 4 Y SPS 2.3 Y ₅ O ₄ F ₇ 100 44 - 19 2 100 0.0 5 ○ ○ 2.8 Example 5 Y SPS 2.7 Y ₅ O ₄ F ₇ 100 79 - 100 4 99 0.0 5 ○ ○ 2.9 Example 6 Y SPS 1.4 Y ₅ O ₄ F ₇ 100 0 - 100 7 99 0.0 3 ○ ○ 3.1 Example 7 Y normal pressure 1.4 Y ₅ O ₄ F ₇ 100 0 - 200 18 97 0.1 3 ○ △ 3.4 Example 8 Y normal pressure 1.5 Y ₅ O ₄ F ₇ 100 4 - 10 3 99 0.0 4 ○ ○ 3.2 Example 9 Y HP 2.0 Y ₅ O ₄ F ₇ 100 19 - 13 3 100 0.0 5 ○ ○ 2.8 Example 10 La SPS 2.4 La ₁₀ O ₇ F ₁₆ 100 48 - 200 5 98 0.0 4 ○ △ 3.4 Example 11 Gd SPS 1.5 Gd ₄ O ₃ F ₆ 100 1 - 25 2 100 0.0 5 ○ ○ 2.8 Example 12 Gd SPS 2.2 Gd ₄ O ₃ F ₆ 100 18 - 200 8 99 0.0 6 ○ ○ 3.3 Example 13 Er SPS 1.9 Er ₅ O ₄ F ₇ 100 11 - 42 5 100 0.0 6 ○ ○ 3.0 Example 14 yb SPS 1.4 Yb ₅ O ₄ F ₇ 100 0 - twenty one 1 (ND) 0.0 3 ○ ○ 3.3 Example 15 yb SPS 2.7 Yb ₅ O ₄ F ₇ 100 96 - 400 10 (ND) 0.3 4 ○ △ 3.8 Example 16 Lu SPS 1.7 Lu ₇ O ₆ F ₉ 100 7 - 16 1 99 0.1 7 ○ ○ 2.5 Comparative example 1 Y normal pressure 1.0 YOF 100 0 - 1500 120 99 0.1 3 △ △ 4.0 Comparative example 2 Y normal pressure 3.0 YF ₃ - 100 - 3300 290 89 3.8 3 ○ △ 6.0 Comparative example 3 Y normal pressure - Y ₂ O ₃ - - 100 10 1 100 0.0 6 △ × 3.5 Comparative example 4 Y SPS 2.5 Y ₅ O ₄ F ₇ 100 60 - 3600 250 86 5.1 1 △ △ 5.4 Comparative example 5 Y SPS 2.0 Y ₅ O ₄ F ₇ 100 twenty two - 2500 140 94 1.1 2 △ △ 4.8 Comparative example 6 Y SPS 1.4 Y ₅ O ₄ F ₇ 100 0 - 700 61 93 1.5 2 △ △ 4.9

As shown in the above Table 2, according to the materials for sintered bodies of each embodiment, the obtained sintered bodies containing REaObFc are dense and have high hardness. Both the immersion test and the plasma test can obtain excellent results for chemical liquid immersion or plasma etching. Tolerance evaluation. On the other hand, in the equivalent product of Patent Document 3, that is, the sintered body obtained by using the sintered body material of Comparative Example 1 containing YOF in a large amount of Al and Si, the resistance to chemical liquid immersion or plasma etching It is lower compared with each embodiment. In addition, as shown in Comparative Example 2, the sintered body obtained by using a sintered body material containing YF ₃ and a large amount of Al and Si has poor density and a high etching rate. As shown in Comparative Example 3, the sintered body containing Y ₂ O ₃ Although the materials used for sintered bodies have small amounts of Al and Si, their sintered bodies also have poor resistance to hydrochloric acid. Furthermore, as shown in Comparative Examples 4 to 6, when REaObFc is included and F/RE is the same as that of the present invention, if the amounts of Al and Si are large, it can be seen that the hardness and density are inferior to those of the respective examples. The tolerance to liquid dipping or plasma etching is poor. [Industrial availability]

By the material for sintered bodies of the present invention and the method of manufacturing a sintered body using the same, the sintered body obtained has excellent chemical resistance and plasma resistance. In addition, the sintered body of the present invention has excellent chemical resistance and plasma resistance.

Figure 1 is an XRD pattern of the material for sintered bodies of Example 3. Fig. 2 is a diagram showing the pore size distribution of the material for sintered bodies of Example 3.

Claims (15)

A material for sintered bodies containing an oxyfluoride of a rare earth element represented by REaObFc (where RE is a rare earth element, b/a is 0.9 or less, and c/a is 1.1 or more), The ratio of the molar number of fluorine element (F) to the molar number of rare earth elements (RE) (F/RE molar ratio) in the entire material is 1.3 or more and 2.8 or less, and The content of aluminum (Al) is 50 ppm by mass or less. For example, the material for sintered bodies according to claim 1, wherein the content of silicon (Si) is 500 ppm by mass or less. For example, in claim 1 or 2, the material for sintered bodies has a pore size distribution measured using the mercury porosimetry method. There are peaks in the range of pore diameters from 0.05 μm to 0.5 μm and from 5 μm to 50 μm. The volume of pores with a pore diameter of 0.05 μm or more and 0.5 μm or less is 0.1 mL/g or more, and the pore diameter of 5 μm or more and 50 μm or less is 0.1 mL/g or more. For example, the material for a sintered body according to claim 1 or 2, wherein in XRD analysis, the crystalline phase other than the oxyfluoride of the rare earth element is substantially composed only of the fluoride of the rare earth element represented by REF ₃ . For example, claim 3 is a material for a sintered body, wherein in the XRD analysis, the crystalline phase other than the oxyfluoride of the rare earth element is substantially composed only of the fluoride of the rare earth element represented by REF ₃ . Such as the material for sintered bodies of claim 1 or 2, wherein REaObFc is selected from RE ₇ O ₆ F ₉ , RE ₆ O ₅ F ₈ , RE ₅ O ₄ F ₇ , RE ₄ O ₃ F ₆ , RE ₃ O ₂ F At least one of ₅ and RE ₂ OF ₄ . Such as the material for sintered bodies of claim 1 or 2, wherein the rare earth element RE of the rare earth element oxyfluoride is selected from Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, One or more of Ho, Er, Tm, Yb and Lu. For materials used for sintered bodies in claim 1 or 2, the loss on ignition is 10 mass% or less. For example, the material for sintered bodies in claim 1 or 2 has a BET specific surface area of 2 m ² /g or more and 10 m ² /g or less. For example, the material for sintered bodies in claim 1 or 2 has a Hausner ratio (tap density/bulk density) of 1.0 or more and 1.3 or less. A sintered body containing an oxyfluoride of a rare earth element represented by REaObFc (where RE is a rare earth element, b/a is 0.9 or less, and c/a is 1.1 or more), The ratio of the molar number of fluorine element (F) to the molar number of rare earth elements (RE) (F/RE molar ratio) in the entire sintered body is 1.3 or more and 2.8 or less, and The content of aluminum (Al) is 50 ppm by mass or less. The sintered body of Claim 11, wherein the content of silicon (Si) is 500 ppm by mass or less. For example, the sintered body of Claim 11 or 12, wherein the crystalline phase other than the oxyfluoride of the rare earth element is substantially composed only of the fluoride of the rare earth element represented by REF ₃ . For example, the sintered body of claim 11 or 12 has a Vickers hardness of 3 GPa or more. For example, the sintered body of claim 13 has a Vickers hardness of 3 GPa or more.