阅读说明：本技术 成膜用或烧结用粉末 (Powder for film formation or sintering ) 是由 松仓贤人 森内诚治 于 2019-07-24 设计创作，主要内容包括：本发明的成膜用或烧结用粉末在X射线衍射测定中观察到立方晶Y-(3)Al-(5)O-(12)的峰和斜方晶YAlO-(3)的峰,斜方晶YAlO-(3)的(112)峰相对于立方晶Y-(3)Al-(5)O-(12)的(420)峰的强度比为0.01以上且低于1。或者,本发明的成膜用或烧结用粉末具有钇及铝的复合氧化物,0.1μm～1μm的细孔容积为0.16mL/g以上。在使用了CuKα射线的2θ＝20°～60°的扫描范围的X射线衍射测定中,来源于立方晶Y-(3)Al-(5)O-(12)的峰优选为显示出最大峰强度的峰。(Cubic crystal Y is observed in X-ray diffraction measurement of the powder for film formation or sintering of the present invention 3 Al 5 O 12 Peak and orthorhombic YAlO of 3 Peak of (1), orthorhombic YAlO 3 Peak of (112) with respect to cubic Y 3 Al 5 O 12 The intensity ratio of the (420) peak of (a) is 0.01 or more and less than 1. Alternatively, the powder for film formation or sintering of the present invention comprises a composite oxide of yttrium and aluminum, and has a pore volume of 0.16mL/g or more in a range of 0.1 to 1 μm. In X-ray diffraction measurement in a scanning range of 20 DEG to 60 DEG 2 theta using CuKa radiation, the X-ray diffraction measurement is derived from cubic Y 3 Al 5 O 12 The peak of (b) is preferably a peak showing the maximum peak intensity.)

1. A powder for film formation or sintering, wherein cubic Y is observed in X-ray diffraction measurement₃Al₅O₁₂Peak and orthorhombic YAlO of₃Peak of (1), orthorhombic YAlO₃Peak of (112) with respect to cubic Y₃Al₅O₁₂The intensity ratio of the (420) peak of (a) is 0.01 or more and less than 1.

2. The film-forming or sintering powder according to claim 1, wherein cubic Y is further observed in X-ray diffraction measurement₂O₃Peak of (2), cubic Y₂O₃Peak of (222) with respect to cubic Y₃Al₅O₁₂The intensity ratio of the (420) peak of (a) is 0.001 or more and less than 0.1.

3. The film forming or sintering powder according to claim 1 or 2, wherein the trigonal Al₂O₃Peak of (104) with respect to cubic Y₃Al₅O₁₂The intensity ratio of the (420) peak of (a) is less than 0.1.

4. The film-forming or sintering powder according to any one of claims 1 to 3, wherein Y is measured by X-ray diffraction₃Al₅O₁₂The crystallite size determined from the half-value width of the peak (420) of (1) is 50nm or more.

5. A powder for film formation or sintering, which is made of a composite oxide of yttrium and aluminum, has a peak in the range of 0.1 to 1 μm in pore diameter measured by mercury intrusion, and has a pore volume of 0.16mL/g or more in pore diameter of 0.1 to 1 μm.

6. The powder for film formation or sintering according to claim 5, wherein a distribution of pore volume versus pore diameter measured by a mercury intrusion method has peaks in a range of pore diameters of 0.1 to 1 μm and in a range of pore diameters of 5 to 50 μm, respectively, and the pore volume of pores having pore diameters of 5 to 50 μm is 0.1mL/g or more.

7. The powder for film formation or sintering according to claim 5 or 6, wherein the BET specific surface area is 1m²/g～5m²/g。

8. The powder for film formation or sintering according to any one of claims 1 to 7, which is a particle having an average particle diameter of 15 μm or more.

9. The film forming or sintering powder according to any one of claims 1 to 8, wherein the powder is derived from cubic Y in X-ray diffraction measurement in a scanning range of 20 ° to 60 ° with CuK α rays 2 θ₃Al₅O₁₂The peak of (a) is a peak showing the maximum peak intensity.

10. A method for producing a coating film, wherein the powder for film formation or sintering according to any one of claims 1 to 9 is formed by a thermal spraying method or a PVD method.

11. A method for producing a sintered body, wherein the powder for film formation or sintering according to any one of claims 1 to 9 is sintered.

12. A coating film formed by depositing the powder for film formation or sintering according to any one of claims 1 to 9 by a thermal spraying method or a PVD method.

13. A sintered body of the film-forming or sintering powder according to any one of claims 1 to 9.

Technical Field

The present invention relates to a powder for film formation or sintering.

Background

Halogen-based gases, argon, oxygen, and the like are used in an etching process in the manufacture of semiconductor devices. In order to prevent corrosion of the etching apparatus caused by these gases, the inside of the etching apparatus is generally coated by thermally spraying a substance having high corrosion resistance. As one of such highly corrosion-resistant substances, a material containing a composite oxide of yttrium and aluminum such as Yttrium Aluminum Garnet (YAG) is known.

For example, patent document 1 describes a thermal spraying powder in which, when measuring the X-ray diffraction of the thermal spraying powder, the ratio of the intensity of the X-ray diffraction peak derived from the (222) plane of yttria to the intensity of the maximum peak among the X-ray diffraction peaks derived from the (420) plane of garnet phase in the composite oxide, the (420) plane of perovskite phase in the composite oxide, and the (-122) plane of monoclinic phase in the composite oxide is 20% or less.

Patent document 2 describes a powder for thermal spraying, which is characterized by containing granulated and sintered particles of an yttrium-aluminum composite oxide obtained by granulating and sintering a raw material powder containing yttrium and aluminum, wherein the total volume of pores having a diameter of 6 μm or less in the granulated and sintered particles is 0.06 to 0.25cm³/g。

Documents of the prior art

Patent document

Patent document 1: US2006/0116274A1

Patent document 2: US2006/0182969A1

Disclosure of Invention

Problems to be solved by the invention

However, the coating obtained by thermal spraying the powder described in patent documents 1 and 2 does not have sufficient corrosion resistance against plasma etching. Accordingly, an object of the present invention is to provide a yttrium-aluminum composite oxide powder which can eliminate the above-mentioned various disadvantages of the conventional techniques.

Means for solving the problems

The present inventors have conducted intensive studies on a structure in which a composite oxide powder of yttrium and aluminum effectively improves the corrosion resistance against plasma etching. As a result, it has been found that the corrosion resistance can be effectively improved by using a specific composition or pore volume.

The present invention has been made in view of the above-mentioned findings, and provides a powder for film formation or sintering, in which Y is observed in X-ray diffraction measurement₃Al₅O₁₂Peak and YAlO of₃Peak of (1), orthorhombic (orthorhombic crystal) YAlO₃Peak of (112) with respect to cubic Y₃Al₅O₁₂The intensity ratio of the (420) peak of (a) is 0.01 or more and less than 1.

The present invention also provides a powder for film formation or sintering, which contains a composite oxide of yttrium and aluminum, has a peak in a range of pore diameters of 0.1 to 1 μm measured by a mercury intrusion method, and has a pore volume of 0.16mL/g or more for pore diameters of 0.1 to 1 μm.

The present invention also provides a method for producing a coating film formed by using the powder and a method for producing a sintered body obtained by sintering the powder.

The present invention also provides a coating film obtained by forming the powder by a thermal spraying method or a PVD method, and a sintered body of the powder.

Drawings

FIG. 1 is an X-ray diffraction chart of the powder obtained in example 1.

FIG. 2 is a pore diameter distribution diagram of the powder obtained in example 1.

Detailed Description

The present invention will be described below based on preferred embodiments thereof. The powder for film formation or sintering of the present invention (hereinafter, also referred to as "the powder of the present invention") is made of a composite oxide containing yttrium and aluminum.

(composition of powder for film formation or sintering)

When the powder of the present invention is subjected to X-ray diffraction measurement, it is observed that the powder is derived from cubic Y₃Al₅O₁₂Diffraction peaks of (yttrium-aluminum garnet) and YAlO derived from rectangular crystal₃The diffraction peak of (1). The inventor finds that: if cubic Y is excluded from the X-ray diffraction measurement₃Al₅O₁₂In addition, also contains orthorhombic YAlO₃And the composition of both is specified, a coating film and a sintered body having high corrosion resistance in plasma etching can be easily obtained. More specifically, it was found that: powder of the invention with Y₃Al₅O₁₂Is slightly higher than the molar ratio of yttrium and YAlO₃The crystal is preferably a rectangular crystal.

Specifically, cubic crystal Y is observed in X-ray diffraction measurement of the powder of the present invention₃Al₅O₁₂Peak and rectangular YAlO of₃Peak, rectangular square crystal YAlO of₃Intensity S2 of peak (112) with respect to cubic Y₃Al₅O₁₂The ratio S2/S1 of the intensity S1 of the (420) peak of (C) is preferably 0.01 or more and less than 1. The reason why the corrosion resistance of the sintered body and the coating obtained from the powder in this range is high is not clear, but the present inventors considered that: if and Y₃Al₅O₁₂Is slightly higher than the molar ratio of yttrium, and YAlO₃In the case of the rectangular crystal, a coating film or a sintered body having a composition stable to plasma etching can be easily obtained. For example, when S2/S1 is less than 1, unstable melilite (Y) can be effectively prevented₄Al₂O₉) The composition appears. From the viewpoint of further improving the corrosion resistance of the coating or sintered body, S2/S1 is more preferably 0.02 to 0.5, and particularly preferably 0.03 to 0.3. In addition, YAlO₃As the complex oxide, many types of crystals such as cubic, orthorhombic, and hexagonal crystals are known as the crystal structure. The inventor considers that: if YAlO is in these crystal structures₃Is a rectangular crystal, and a coating film or a sintered body having a composition stable to plasma etching can be easily obtainedAnd (3) a body. The crystal structure is disclosed in ICDD powder diffraction database 01-074-. In the present specification, the peak intensity ratio refers to a ratio of heights of two peaks, and does not refer to a ratio of integrated intensities of two peaks (hereinafter, referred to as "peak intensity", the same meaning is applied thereto).

Cubic Y in X-ray diffraction measurement using CuK alpha rays₃Al₅O₁₂The peak (420) of (a) is observed in the vicinity of 33 °, specifically, in the range of 33.3 ° ± 0.5 ° in 2 θ. Further, orthorhombic YAlO in X-ray diffraction measurement using CuK α rays₃The peak of (112) of (a) is generally observed in the vicinity of 2 θ ═ 34 °, specifically, in the range of 34.2 ° ± 0.5 °. The powder of the present invention is derived from cubic Y in X-ray diffraction measurement in a scanning range of 20 ° to 60 ° with CuK α rays₃Al₅O₁₂The peak of (A) is preferably a peak showing the maximum peak intensity, particularly cubic Y₃Al₅O₁₂The peak of (420) is preferably a peak showing the maximum peak intensity.

The powder of the present invention reflects the YAlO content in amounts as described above₃The YAlO₃With yttrium-aluminum-garnet Y₃Al₅O₁₂In contrast, the Y/Al ratio is relatively high, and a peak of yttria is sometimes observed in X-ray diffraction measurement. Cubic Y in the case where a peak of yttria is observed in X-ray diffraction measurement₂O₃Intensity S3 of peak (222) of (2) with respect to cubic Y₃Al₅O₁₂The ratio S3/S1 of the intensity S1 of the (420) peak of (a) is preferably 0.001 or more and less than 0.1 from the viewpoint of acting as an aid for reaction sintering of a complex oxide of yttrium and aluminum at the time of production of a sintered body and making it easier to obtain a denser sintered body. It is also preferable that S3/S1 is 0.001 or more and less than 0.1 from the viewpoint of improving the corrosion resistance of the coating and sintered body. From these viewpoints, S3/S1 is more preferably 0.002 to 0.05, and particularly preferably 0.003 to 0.03. Cubic Y in X-ray diffraction measurement using CuK alpha rays₂O₃The (222) peak of (a) is generally observed at 29 ° 2 θ, specifically at 29.2 ° ± 0.5 °.

The powder of the present invention is preferably improved in corrosion resistance to plasma etching because no peak of an alumina phase is observed or even a very small peak is observed in X-ray diffraction measurement. From this viewpoint, trigonal Al₂O₃Intensity of peak (104) of (S4) with respect to cubic Y₃Al₅O₁₂The ratio S4/S1 of the intensity S1 of the (420) peak of (A) is preferably less than 0.1, more preferably 0.01 or less, particularly preferably 0.001 or less, and most preferably no trigonal Al is observed₂O₃Peak (104) of (1). Trigonal Al crystal Al in X-ray diffraction measurement using CuK alpha ray₂O₃The peak (104) of (a) is generally observed at 2 θ ═ 35 °, specifically at 35.2 ° ± 0.5 °.

From the viewpoint of further improving the corrosion resistance, it is preferable that the powder of the present invention is substantially not observed to be derived from Y in X-ray diffraction measurement₃Al₅O₁₂、YAlO₃、Y₂O₃And Al₂O₃Peaks of other components. In the scanning range of 20-60 degrees of 2 theta, derived from Y₃Al₅O₁₂、YAlO₃、Y₂O₃And Al₂O₃Intensity of peak of other component with respect to cubic Y₃Al₅O₁₂The height ratio of the (420) peak of (a) is preferably 0.1 or less, more preferably 0.05 or less, further preferably 0.03 or less, particularly preferably 0.01 or less, and most preferably 0.001 or less.

(crystallite size)

The powder of the invention consists of cubic crystals Y₃Al₅O₁₂Has a crystallite size of 50nm or more determined from the half-value width of the peak (420) and cubic crystal Y in the obtained coating or sintered body₃Al₅O₁₂The crystallinity of (a) is preferably high, and the corrosion resistance of the coating or sintered body is preferably further improved. From this viewpoint, the crystallite size is preferably 60nm or more, more preferably 70nm or more, and particularly preferably 80nm or more. The crystallite size is preferably 110nm or less, more preferably 110nm or less, from the viewpoint of ease of production of the powder of the present invention and reduction in pore volume due to grain growthIs selected to be 100nm or less. The crystallite size is determined by the Scherrer formula, and specifically can be determined by the method described in the examples described later.

In order to make the powder of the present invention have the above composition and crystallite size, in a preferred method for producing the powder of the present invention, which will be described later, the particle diameters of the yttrium source powder and aluminum source powder as raw materials may be adjusted, or the firing temperature of the raw material powder may be adjusted.

(pore volume)

The inventor finds that: when the pore volume of the powder of the present invention is set to a specific range, the surface roughness of the obtained coating film and the density of the sintered body can be controlled. The following are found: in particular, when the powder of the present invention is granulated, it is advantageous to set the pore volume in a specific range. The surface roughness of the coating and the compactness of the sintered body are related to the corrosion resistance to plasma etching. Therefore, the pore volume of the powder of the present invention can control the corrosion resistance of the coating film and the sintered body. Specifically, the powder of the present invention preferably has a pore volume of 0.16mL/g or more, wherein the pore diameter is 0.1 to 1 μm. The pore volume having a pore diameter of 0.1 to 1 μm is derived from the voids between the primary particles in the powder of the present invention. When the pore volume of the pore diameter in this range is 0.16mL/g or more, the surface roughness of the obtained coating film is reduced, and the obtained sintered body becomes a dense sintered body. The reason is not clear, but the present inventors speculate that one of the reasons is: the powder of the present invention having a pore volume within the above range is easily melted by the primary particles constituting the particles being fine and having a pore volume equal to or greater than a certain level, and thus heat is efficiently transmitted. On the other hand, the powder for thermal spraying described in patent document 2 has a pore volume of 0.1 to 1 μm as determined based on FIG. 1 of the document, and is 0.05mL/g, which is out of the range of the pore volume of the present invention, that is, less than 0.16 mL/g.

From the viewpoint of improving the corrosion resistance of the obtained film and sintered body against plasma etching, the pore volume V1 of the powder of the present invention having a pore diameter of 0.1 to 1 μm is preferably 0.16mL/g or more, more preferably 0.20mL/g or more, and particularly preferably 0.24mL/g or more. The pore volume V1 of the powder of the present invention is preferably 1.0mL/g or less, more preferably 0.4mL/g or less, from the viewpoint that the strength of the granules is reduced when the gaps between the primary particles become too wide.

In the powder of the present invention, it is also preferable that the pore volume V2 having a pore diameter of 5 to 50 μm is 0.1mL/g or more from the viewpoint of improving the corrosion resistance. The pore volume having a pore diameter of 5 to 50 μm is derived from the space of the voids between the secondary particles in the powder of the present invention. The pore volume V2 in the powder of the present invention is more preferably 0.15mL/g or more, and particularly preferably 0.20mL/g or more. The pore volume V2 of the powder of the present invention is preferably 0.5mL/g or less, more preferably 0.4mL/g or less, from the viewpoint of ensuring sufficient fluidity.

From the viewpoint of further improving the corrosion resistance of the coating and sintered body obtained by using the powder of the present invention, the ratio V1/V2 of the pore volume V1 to the pore volume V2 measured by the mercury intrusion method is preferably 0.3 or more, more preferably 0.4 or more, and particularly preferably 0.5 or more. A V1/V2 ratio of 1.0 or less is preferred in view of ensuring an appropriate particle density.

From the viewpoint of further improving the corrosion resistance of the coating and sintered body obtained by using the powder of the present invention, at least one peak is preferably observed in the range of pore diameter of 0.1 μm to 1 μm in the distribution of pore volume to pore diameter (horizontal axis: pore diameter, vertical axis: log differential pore volume) measured by the mercury intrusion method. From the viewpoint of further effectively improving the corrosion resistance, at least one peak having a pore diameter in the range of 0.1 μm to 1 μm is more specifically observed in the range of 0.2 μm to 0.9 μm, and particularly preferably observed in the range of 0.3 μm to 0.8 μm. Hereinafter, a peak having a pore diameter in the range of 0.1 μm to 1 μm in the pore volume distribution may be referred to as a pore 1 st peak.

The powder of the present invention preferably has at least one peak in the distribution of pore volume to pore diameter (horizontal axis: pore diameter, vertical axis: log differential pore volume) measured by the mercury intrusion method, in addition to the range of pore diameter of 0.1 μm to 1 μm, in the range of pore diameter of 5 μm to 50 μm, from the viewpoint of further improving the corrosion resistance. From the viewpoint of further improving the ease of production of the powder of the present invention and the corrosion resistance of the coating and sintered body, it is more preferable that at least one peak having a pore diameter in the range of 5 to 50 μm is observed in more detail in the range of 7 to 35 μm, and it is particularly preferable that at least one peak having a pore diameter in the range of 8 to 25 μm is observed. Hereinafter, a peak having a pore diameter in the range of 5 μm to 50 μm in the pore volume distribution may be referred to as a pore 2 nd peak.

In order to provide the powder of the present invention with the pore volume, the particle diameters of the yttrium source powder and the aluminum source powder as raw materials may be adjusted or the firing temperature may be adjusted in a preferable method for producing the powder of the present invention to be described later.

(particle diameter)

The powder of the present invention is preferably a granule in view of further improving the effect of improving the corrosion resistance by having the above-mentioned specific pore volume or having the above-mentioned specific composition. The average particle diameter of the particles is preferably 15 to 100. mu.m, more preferably 20 to 80 μm, and particularly preferably 25 to 60 μm, from the viewpoint of easily obtaining the powder of the present invention satisfying the pore volume distribution described above and from the viewpoint of fluidity when it is used as a thermal spray material. The average particle diameter is a particle diameter (D) having a cumulative volume from a small particle diameter side of 50% obtained by a laser diffraction/scattering particle size distribution measurement method₅₀) The measurement can be carried out by the method described in the examples described later.

(BET specific surface area)

The BET specific surface area of the powder of the invention is 1m²/g～5m²The volume ratio of the particles is preferably in the range of a volume density suitable for film formation and sintering, and a good handling during processing. From these viewpoints, the BET specific surface area of the powder of the present invention is more preferably 1.5m²/g～4.5m²Per g, particularly preferably 2.0m²/g～4.0m²(ii) in terms of/g. BET specific surface areaThe measurement can be performed by the BET one-point method, specifically, the method described in the examples described later.

Next, a preferred method for producing the powder of the present invention will be described. The present production method preferably includes the following 1 st step to 5 th step. The 1 st step and the 2 nd step may be performed first or simultaneously. Hereinafter, each step will be described in detail.

Step 1: d obtaining particles of an aluminium source₅₀Is a slurry of particles of an aluminum source of 0.05 to 2.0 μm.

Step 2: obtaining particles of yttrium source D₅₀A slurry of particles of yttrium source of 0.1 to 2.0 μm.

Step 3: the slurry of aluminum source particles obtained in the step 1 and the slurry of yttrium source particles obtained in the step 2 are mixed.

Step 4: the slurry as the mixture obtained in the step 3 is granulated by a spray dryer to obtain a granulated substance.

Step 5: the granulated substance obtained in the step 4 is fired at a temperature of 800 to 1700 ℃ to obtain particles of a composite oxide of yttrium and aluminum.

[ 1 st step ]

In this step, a slurry having particles of an aluminum source with a predetermined particle diameter is obtained. The particle diameter of the aluminum source particles is measured by using a laser diffraction/scattering particle diameter/particle size distribution measuring instrument, D, from the viewpoint of smoothly obtaining a powder having the above-mentioned composition and pore volume or specific surface area₅₀Preferably 0.05 to 2.0. mu.m, more preferably 0.1 to 1.0. mu.m. D of particles of an aluminum source₅₀The measurement method (2) is explained in the examples described later. As the aluminum source, 1 or 2 or more selected from aluminum oxide (Alumina), aluminum oxyhydroxide, and aluminum hydroxide are preferably used.

In the step 1, particles of an aluminum source are mixed with a liquid medium and sufficiently stirred to obtain a slurry of the particles of the aluminum source. If necessary, the aluminum source is pulverized before or after mixing with the liquid medium. The pulverization method may be the same as the pulverization method of yttrium source particles described later. The type of the liquid medium is not particularly limited, and water or various organic solvents can be used, for example. As the aluminum source, an aluminum source having a high specific surface area is preferably used in view of reactivity. In particular, since the viscosity of the slurry increases when the maximum specific surface area is reached, various dispersants or binders may be added to the slurry along with the mixing of the particles of the aluminum source and the liquid medium. Examples of the dispersant include polyacrylic acid polymers, carboxylic acid copolymers, acetic acid, and ammonia. When a dispersant is added to the slurry of particles of the aluminum source, the amount of 0.001 to 1 part by mass per 100 parts by mass of the aluminum source in terms of alumina is preferable from the viewpoint of suppressing the quality of the obtained powder and the increase in viscosity, and more preferably 0.01 to 0.1 part by mass.

[ 2 nd step ]

In this step, D of yttrium source particles is obtained₅₀The size is 0.1-2.0 μm. As the yttrium source, 1 or 2 or more kinds selected from yttrium oxide, yttrium hydroxide, yttrium oxalate, and yttrium carbonate are preferably used. These commercial products generally have particle size ratios D as described above₅₀In this case, the yttrium source is pulverized.

As the pulverization, either dry pulverization or wet pulverization can be applied. The pulverization may be carried out in 1 stage, or may be carried out in 2 or more stages. In view of cost and labor, the pulverization is preferably carried out in 1 stage. After the pulverization, a liquid medium such as water is preferably added to form a slurry. In the case of dry pulverization, various dry pulverizers such as a mill, a jet mill, a ball mill, a hammer mill, and a pin mill can be used. On the other hand, when wet grinding is performed, various wet grinders such as a ball mill and a bead mill can be used.

The degree of pulverization of the yttrium source particles in this step is measured by using a laser diffraction/scattering particle size/particle size distribution measuring instrument₅₀Preferably about 0.1 to 2.0 μm. By performing pulverization to this extent, a powder having the desired pore volumes V1 and V2 and a specific surface area can be easily obtained. From these viewpointsStarting from, D₅₀More preferably 0.2 to 1.5 μm. D of particles of yttrium source₅₀The measurement method (2) is explained in the examples described later.

[ 3 rd step ]

In this step, the slurry of aluminum source particles obtained in the 1 st step and the slurry of yttrium source particles obtained in the 2 nd step are mixed to prepare a mixed slurry of yttrium source particles and aluminum source particles. At this time, pure water was additionally charged to adjust the concentration of the mixed slurry. Regarding the mixing ratio of the yttrium source and the aluminum source, the yttrium of the yttrium source is preferably more than 0.6 mol and う mol or less, more preferably more than 0.61 mol and 0.7 mol or less, relative to 1 mol of aluminum of the aluminum source.

The concentration of the slurry in this step is preferably set to 50 to 1500g/L, particularly 100 to 1000g/L, in total, when the yttrium source is converted to yttrium oxide and the aluminum source is converted to aluminum oxide. By setting the slurry concentration within this range, excessive consumption of energy can be suppressed, and the viscosity of the slurry becomes appropriate, so that spraying can be stabilized.

[ 4 th step ]

In this step, the slurry obtained in the step 3 is granulated by a spray dryer to obtain a granulated substance containing yttrium and aluminum. The rotational speed of the atomizer during operation of the spray dryer is preferably set to 5000min^-1～30000min^-1. By setting the rotation speed to 5000min^-1As described above, the particles of the yttrium source and the particles of the aluminum source in the slurry can be sufficiently dispersed, and thus a uniform granulated substance can be obtained. On the other hand, by setting the rotation speed to 30000min^-1Hereinafter, particles having the above pore 2 nd peak are easily obtained. From these viewpoints, the rotation speed of the atomizer is more preferably set to 6000min^-1～25000min^-1。

The inlet temperature when the spray dryer is operated is preferably set to 150 to 300 ℃. By setting the inlet temperature to 150 ℃ or higher, the solid content can be sufficiently dried, and pellets with less residual moisture can be easily obtained. On the other hand, by setting the inlet temperature to 300 ℃ or lower, consumption of useless energy can be suppressed.

[ procedure 5 ]

In this step, the granulated substance obtained in the step 4 is fired to obtain particles of a composite oxide of yttrium and aluminum. The degree of firing is a factor for controlling the composition of the target powder, pore volume peak and specific surface area of pores having pore diameters of 0.1 to 1 μm. More specifically, the firing temperature is preferably 800 to 1600 ℃. By setting the firing temperature to 800 ℃ or higher, the desired composition ratio can be easily obtained. On the other hand, by setting the firing temperature to 1600 ℃ or lower, particles having the 1 st peak of the target pore size distribution and the specific surface area can be easily obtained. From these viewpoints, the firing temperature is more preferably 900 to 1550 ℃, and still more preferably 1000 to 1500 ℃.

The firing time is preferably set to 1 to 48 hours, provided that the firing temperature is within the above-described range. More preferably, it is set to 3 to 24 hours. The atmosphere for firing is not particularly limited, but since oxidation by firing is required depending on the kind of the aluminum source, oxygen (O) becomes necessary₂) Therefore, it is preferably carried out in an atmosphere containing oxygen such as the atmosphere.

The powder of the present invention obtained as described above is used for various film-forming methods such as a thermal spraying method, a Physical Vapor Deposition (PVD) method, a Chemical Vapor Deposition (CVD) method, an Aerosol Deposition (AD) method, and a cold spray method, and is suitably used for plasma spraying, which is one of the thermal spraying methods, for example. The plasma spraying may be atmospheric pressure plasma spraying or reduced pressure plasma spraying. Examples of the Physical Vapor Deposition (PVD) method include an ion plating method and a sputtering method. Examples of the substrate to be subjected to film formation include various metals such as aluminum, various alloys such as aluminum alloys, various ceramics such as alumina, and quartz.

The powder of the present invention can be suitably used as a material for ceramic parts. Specifically, when the powder for film formation or sintering of the present invention is used as a raw material for a ceramic member produced by, for example, a general sintering method, a pressing method, an HP method, a CIP method, a HIP method, an SPS method, or the like, a ceramic member excellent in smoothness, etching resistance, and the like can be obtained. The sintering temperature is not particularly limited, but is preferably 1200 to 1800 degrees centigrade, more preferably 1300 to 1700 degrees centigrade, and the firing atmosphere may be any of an oxidizing atmosphere such as an atmospheric atmosphere and an inert gas atmosphere. Such ceramic parts are suitably used, for example, in jigs for electronic materials or for firing the same, members for semiconductor manufacturing apparatuses, etching and film forming apparatuses using plasma, and the like. The sintered body produced by sintering the powder for film formation or sintering of the present invention can be suitably used as a target (material for film formation) for PVD methods such as ion plating and vacuum deposition.

By using the powder of the present invention, a thermal spray film having high corrosion resistance against plasma etching can be obtained, as compared with a thermal spray material using a conventionally proposed yttrium/aluminum composite oxide, by using particles containing a yttrium/aluminum composite oxide and having a specific composition or a specific pore volume. The powder for film formation or sintering of the present invention can similarly obtain a film having high corrosion resistance even in a method other than thermal spraying such as PVD method, and can similarly obtain a sintered body having high corrosion resistance even when the powder is prepared as a sintered body. The coating film or sintered body obtained by using the powder for film formation or sintering of the present invention has high corrosion resistance, and is useful for a component of a semiconductor manufacturing apparatus using plasma etching, coating thereof, or the like.

In order to improve the corrosion resistance against plasma etching, an example of the composition of the coating film formed by using the powder of the present invention includes a composition of S2/S1 preferably 0 to 0.3, more preferably 0 to 0.2, and S3/S1 preferably 0 to 0.1, more preferably 0 to 0.05, but is not limited thereto. The composition of the sintered body of the powder of the present invention includes, for example, a composition of S2/S1 of preferably 0 to 0.3, more preferably 0 to 0.2, and S3/S1 of preferably 0 to 0.2, more preferably 0 to 0.15, but is not limited thereto. The preferable upper limit of S4/S1 of the coating and sintered body can be set to the same level as the powder of the present invention. The film and the sintered body are applied to the radiation source and the sintered bodyIn the X-ray diffraction measurement of the scanning range, the X-ray diffraction measurement is derived from cubic Y₃Al₅O₁₂The peak of (A) is preferably a peak showing the maximum peak intensity, particularly cubic Y₃Al₅O₁₂The peak of (420) is preferably a peak showing the maximum peak intensity. The above-mentioned coating and sintered body are such that Y is not observed in X-ray diffraction measurement of the above-mentioned radiation source and the above-mentioned scanning range₃Al₅O₁₂、YAlO₃、Y₂O₃And Al₂O₃Peaks of other components or, if observed, the peak height relative to the cubic crystal Y₃Al₅O₁₂The height of the (420) peak is also preferably 5% or less, more preferably 3% or less, and further preferably 1% or less.

The coating film and sintered body obtained by film formation using the powder of the present invention have a low etching rate in plasma etching. Specifically, the etching rate of the film and the sintered body measured by the method described in the examples described later is preferably 3 nm/min or less, and more preferably 2 nm/min or less.

In the case where the coating film is produced using the powder of the present invention as a raw material, the coating film is preferably a coating film having low surface roughness in order to improve corrosion resistance against plasma etching. The surface roughness of the coating can be measured by the method described in the examples described later. Such a coating film can be obtained by forming the powder for film formation or sintering of the present invention.

In order to improve the corrosion resistance against plasma etching, the open porosity of the sintered body of the present invention is preferably 1% or less, more preferably 0.5% or less. The open porosity can be measured by the archimedes method in accordance with JIS R1634, specifically, by the following method. Such a sintered body can be obtained by sintering the powder for film formation or sintering of the present invention.

< method for measuring Open Porosity (OP) >

The sintered body was put into distilled water and held under reduced pressure by a diaphragm type vacuum pump for 1 hour, and then the weight W2[ g ] in water was measured. Further, the remaining water was removed with a wet cloth, and the saturated weight W3[ g ] was measured. Thereafter, the sintered body was sufficiently dried in a dryer, and the dried weight W1 g was measured. The open porosity OP was calculated by the following equation.

OP＝(W3-W1)/(W3-W2)×100(％)

Examples

The present invention will be described in further detail below with reference to examples. The scope of the invention is not limited to the embodiments. Table 1 shows production conditions (type of aluminum material, amount of aluminum material and yttrium oxide material used, atomizer rotation speed in step 4, and firing temperature in step 5) in each example and comparative example.

[ example 1 ]

(step 1)

10kg of alpha-alumina was mixed with pure water and stirred to prepare 250g/L of an aluminum source slurry. D of alumina measured by Microtrac HRA (Dispersion treatment with 300W ultrasonic wave)₅₀And 0.13 μm. D₅₀The specific measurement method of (3) is as follows. A sample (0.1 to 1 g) was added to a 100mL glass beaker, and about 100mL of a 0.2 mass% aqueous solution of sodium hexametaphosphate was added thereto. A beaker containing a sample and 100mL of a 0.2 mass% aqueous solution of sodium hexametaphosphate was placed in a U.S. Pat. No. 300T (output: 300W) ultrasonic homogenizer manufactured by Nippon Seiko corporation and subjected to ultrasonic dispersion treatment for 5 minutes to prepare a slurry. The slurry was dropped into the chamber of a sample circulator of Microtrac HRA, manufactured by Nikkiso K.K. until the concentration was judged to be appropriate. As the dispersion medium, a 0.2 mass% aqueous solution of sodium hexametaphosphate was used.

(step 2)

14kg of yttrium oxide and 20L of pure water were wet-ground in a bead mill. D of yttria as measured by Microtrac HRA (Dispersion treatment with 300W ultrasound)₅₀The pulverization is carried out so as to be 0.6 to 0.8. mu.m. After the pulverization, pure water was further added to adjust the concentration, thereby obtaining 550g/L of yttrium source slurry. D₅₀The specific measurement method of (3) is set to be the same as in the step 1.

(step 3)

The slurry obtained in the step 1 is mixed with the slurry obtained in the step 2. After the mixing, pure water was further added to adjust the concentration, thereby obtaining a mixed slurry having a total concentration of yttrium oxide and aluminum oxide of 200 g/L.

(step 4)

The mixed slurry obtained in the step 3 was granulated and dried by a spray dryer (manufactured by gawa basic processing machine, ltd.) to obtain a granulated product. The operating conditions of the spray dryer are as follows.

Slurry feed rate: 75 mL/min

Atomizer rotation speed: 12500rpm

Inlet temperature: 250 deg.C

(step 5)

The granulated material obtained in the step 4 was placed in an alumina container and fired in an electric furnace in an atmospheric atmosphere to obtain granulated particles. The firing temperature was set to 1400 ℃ and the firing time was set to 6 hours. The particles are substantially spherical in shape. In this manner, the intended composite oxide powder was obtained.

[ measurement/formation of coating ]

The powder obtained in example 1 was subjected to X-ray diffraction measurement by the following method, and an X-ray diffraction pattern was obtained. The results are shown in fig. 1. Based on the obtained X-ray diffraction pattern, for cubic Y₃Al₅O₁₂(420) Peak, rectangular Crystal YAlO of₃Peak (112), cubic Y₂O₃Peak (222) and trigonal Al₂O₃The relative intensity was calculated from the (104) peak of (1). In addition, the pore 1 st peak, the pore 2 nd peak, the pore volume, the crystallite size, the BET specific surface area and the particle diameter (D) were measured by the methods described below₅₀). These results are shown in table 2 below. In the X-ray diffraction pattern of the powder obtained in example 1 in the scanning range of 20 ° to 60 °, no contribution from Y was observed₃Al₅O₁₂、YAlO₃、Y₂O₃And Al₂O₃Peaks of other components. IntoOn the other hand, a film was obtained using the powder obtained in example 1 by the following [ film formation conditions by thermal spraying method ].

[ X-ray diffraction measurement ]

An apparatus: ultimaIV (manufactured by Rigaku Corporation)

Source of radiation: CuKalpha ray

Tube voltage: 40kV

Tube current: 40mA

Scanning speed: 2 degree/min

Stepping: 0.02 degree

Scan range: 2 theta is 20-60 DEG

[ pore volume of 0.1 to 1 μm, pore volume of 5 to 50 μm ], pore number 1, pore number 2

An apparatus: AutoPore IV (Micromeritics, Inc.)

1 st pore peak: in general, when the pore size distribution of the primary particle-containing granules was measured, 2 peaks were obtained, and the peak on the smaller diameter side among the peaks was set as the 1 st pore peak.

Pore peak 2: among the above peaks, the peak on the larger diameter side was set as the 2 nd peak.

Pore volume of 0.1 μm to 1 μm: the cumulative value of pore volume of pores having pore diameters of 0.1 to 1 μm

Pore volume of 5 μm to 50 μm: the cumulative value of pore volume with pore diameters of 5 μm to 50 μm is shown in FIG. 2.

[ crystallite sizing ]

Measurement of X-ray diffraction measurement based on the above-mentioned terms, from cubic Y₃Al₅O₁₂The half-value width of the peak of (420) is calculated by the Scherrer equation.

[ BET specific surface area measurement ]

The measurement was carried out by the BET one-point method using a full-automatic specific surface area meter Macsorb model-1201 manufactured by MOUNTECH. The gas used was set to a nitrogen-helium mixed gas (nitrogen 30 vol%).

[ measurement of particle size ]

The measurement was performed by using a Microtrac HRA manufactured by Nikkiso K.K. In the measurement, a 0.2 mass% aqueous solution of sodium hexametaphosphate was used as a dispersion medium, and a sample (particles) was added to a chamber of a sample circulator of Microtrac HRA until the apparatus determined to have an appropriate concentration.

[ film formation conditions by thermal spraying ]

As the substrate, a 20mm square aluminum alloy sheet was used. The surface of the substrate was subjected to plasma spraying using the powder obtained in example 1. As a powder supply apparatus, TWIN-SYSTEM 10-V manufactured by Plasma Technique was used. F4 manufactured by Sulzer Metco was used as a plasma spraying device. Plasma spraying was performed so that the film thickness became about 60 μm under the conditions of a stirring rotational speed of 50%, a carrier gas flow rate of 2.5L/min, a supply scale of 10%, a plasma gas of Ar/H2, an output of 35kW, and an apparatus-substrate distance of 150 mm.

When the film obtained above was subjected to X-ray diffraction measurement by the above-described method, S2/S1 was 0.04, S3/S1 was 0.01, and S4/S1 was 0, and the film was observed to be a cubic Y crystal₃Al₅O₁₂The (420) peak of (2), which is not derived from Y, is not observed₃Al₅O₁₂、YAlO₃、Y₂O₃And Al₂O₃Peaks of other components.

[ example 2 ]

A powder of a composite oxide was obtained in the same manner as in example 1, except that the firing temperature in the 5 th step of example 1 was set to 1500 ℃, and evaluation and film formation were performed in the same manner as in example 1.

[ example 3, example 5 ]

The amount of yttria in the 2 nd step of example 1 was set to 13.6kg in example 3 and 14.6kg in example 5, and evaluation and film formation were performed in the same manner as in example 1.

[ example 4 ]

A powder of a composite oxide was obtained in the same manner as in example 3, except that the firing temperature in the 5 th step of example 3 was set to 1500 ℃, and evaluation and film formation were performed in the same manner as in example 1.

[ example 6 ]

A powder of a composite oxide was obtained in the same manner as in example 5, except that the firing temperature in the 5 th step in example 5 was set to 1500 ℃, and evaluation and film formation were performed in the same manner as in example 1.

[ example 7 ]

A powder of a composite oxide was obtained in the same manner as in example 1, except that the rotational speed of the atomizer in the 3 rd step of example 1 was set to 20000rpm, and evaluation and film formation were performed in the same manner as in example 1.

[ example 8 ]

A powder of a composite oxide was obtained in the same manner as in example 1, except that the atomizer rotation speed in step 3 of example 1 was set to 25000rpm, and evaluation and film formation were performed in the same manner as in example 1.

[ example 9 ]

The aluminum source in the 1 st step of example 1 was changed to aluminum oxyhydroxide. The amount of aluminum oxyhydroxide used was set to 10kg in terms of alumina. The firing temperature in step 5 was set to 1300 ℃. Except for these points, a powder of a composite oxide was obtained in the same manner as in example 1, and evaluation and film formation were performed in the same manner as in example 1.

[ example 10 ]

A powder was obtained in the same manner as in example 9 except that the firing temperature in the 5 th step in example 9 was set to 1200 ℃.

[ example 11 ]

The aluminum source in the 1 st step of example 1 was changed to aluminum hydroxide. The amount of aluminum hydroxide used was set to 10kg in terms of alumina. Except for this point, a powder of a composite oxide was obtained in the same manner as in example 1, and evaluation and film formation were performed in the same manner as in example 1.

[ example 12 ]

A powder of a composite oxide was obtained in the same manner as in example 11, except that the firing temperature in the 5 th step of example 10 was set to 1300 ℃, and evaluation and film formation were performed in the same manner as in example 1.

[ comparative example 1 ]

A precipitate obtained by neutralizing a solution obtained by mixing 2.78kg of yttrium nitrate and 3.59kg of aluminum nitrate with ammonia was washed, filtered, dried at 120 ℃ and then disintegrated, and then fired at 1200 ℃. 2kg of the obtained calcined product was pulverized by a dry ball mill, and then wet-pulverized by adding 2L of pure water to a bead mill. D of the fired product obtained by Microtrac HRA measurement₅₀The pulverization is carried out so as to have a particle size of 1.5 to 2.5. mu.m. After the pulverization, pure water was further added to adjust the concentration, thereby obtaining 550g/L slurry. The slurry was used to perform the 4 th step, and the firing temperature in the 5 th step was set to 1650 ℃.

[ comparative example 2 ]

A powder of a composite oxide was obtained in the same manner as in example 1, except that the steps 2 and 3 of example 1 were not performed and the firing temperature was set to 1400 ℃. However, in the measurement of the crystallite size, in this comparative example, the crystallite size was not determined from the cubic crystal Y₃Al₅O₁₂Instead of the (420) peak of (A) is composed of trigonal Al₂O₃The crystallite size was calculated from the (104) peak of (a).

[ comparative example 3 ]

A powder of a composite oxide was obtained in the same manner as in example 1, except that the steps 1 and 3 of example 1 were not performed and the firing temperature was set to 1400 ℃. However, in the measurement of the crystallite size, in this comparative example, the crystallite size was not determined from the cubic crystal Y₃Al₅O₁₂Instead of the (420) peak of (A) is constituted by cubic crystals of Y₂O₃The crystallite size was calculated from the (222) peak of (a).

[ example 13 ]

A film was formed from the powder of the composite oxide obtained in example 1 by a PVD method under the following conditions.

(film formation by PVD method)

As the substrate, a 20mm square aluminum alloy sheet was used. The base material was subjected to film formation by a high-frequency excitation ion plating method which is one of PVD methods. The film forming conditions were set to 0.02Pa for argon pressure, 0.6kW for EB output, 1kW for RF output, 1.5kV for acceleration voltage, and 300mm for the distance between the substrate and the evaporation source, so that the film thickness became 5 to 20 μm.

[ example 14 ]

The powder obtained in example 1 was die-molded at a pressure of 20 MPa. The obtained molded body was fired at 1650 ℃ for 2 hours in an atmospheric atmosphere, and naturally cooled to 50 ℃ in an electric furnace to obtain a sintered body. The obtained sintered body was sufficiently densified so that the open porosity was 0.4% as measured by the archimedes method. The etching rate measured by the method described later was 0.1 nm/min.

When the sintered body obtained in example 14 was subjected to X-ray diffraction measurement by the above-described method, S2/S1 was 0.05, S3/S1 was 0.12, and S4/S1 was 0, all of which were observed with respect to cubic Y₃Al₅O₁₂The (420) peak of (2), which is not derived from Y, is not observed₃Al₅O₁₂、YAlO₃、Y₂O₃And Al₂O₃Peaks of other components.

[ comparative example 4 ]

The powder obtained in comparative example 1 was processed in the same manner as in example 14 to obtain a sintered body. The open porosity was 2%. The etching rate measured by the method described later was 0.3 nm/min.

The surface roughness and the etching rate of the film formed above were measured by the following methods. In addition, the etching rate was measured for the sintered body by the same method.

The surface roughness of the film was measured in the 20mm square aluminum alloy sheet subjected to various film formation methods.

[ measurement of surface roughness of film ]

The arithmetic average roughness (Ra) and the maximum height roughness (Rz) were determined using a stylus type surface roughness measuring instrument (JIS B0651: 2001) (JIS B0601: 2001). A stylus surface profiler P-7 manufactured by KLA-Tencor was used as a stylus surface roughness measuring instrument. The measurement conditions were set to evaluation length: 5mm, measurement speed: 100 μm/sec. The average of the three points was found.

[ measurement of plasma etching Rate ]

A heat-resistant adhesive tape was attached to half of the coating film of a 20mm square aluminum alloy sheet subjected to various film formation methods, and the sheet was placed in a chamber of an etching apparatus (RIE-10 NR, manufactured by Samco Co., Ltd.) with the coating film facing upward, and plasma etching was performed to measure the etching rate. The plasma etching conditions were set as follows. In addition, instead of the film, the etching rate was measured for the sintered body. As for the sintered body, a sintered body sintered to a size of φ 16mm × 2mm was subjected to measurement. The etching rate was calculated by measuring the difference in level between the plasma exposed surface and the non-exposed surface from which the adhesive tape was peeled off after plasma irradiation by the above-described surface roughness measurement. Three points were set for each 1 film at the measurement point, and the average value of these points was determined.

Atmospheric gas: CF (compact flash)₄/O₂15/30/20 (cc/min)

High-frequency power: RF 300W

Pressure: 5Pa

Etching time: 8 hours

TABLE 1

Industrial applicability

When the powder for film formation or sintering of the present invention is used, a coating film or a sintered body having high corrosion resistance against plasma etching can be easily formed.