Yttrium fluoride-based sprayed coating, sprayed member, and method for producing yttrium fluoride-based sprayed coating

Abstract

A yttrium fluoride-based sprayed film containing YF3 crystal phase of an orthorhombic system, not containing YF3 crystal phase other than the orthorhombic system, and having a Vickers hardness of 350 or more is produced by plasma spraying of a sprayed powder containing YF3 crystal phase of an orthorhombic system, not containing YF3 crystal phase other than the orthorhombic system. A yttrium fluoride-based sprayed film having high film hardness and small amount of particles generated when exposed to halogen-based gas plasma can be provided, and such a sprayed film is excellent as a sprayed film formed in a member for a semiconductor manufacturing apparatus used in a semiconductor manufacturing process. In addition, according to the present application, such a yttrium fluoride-based sprayed film can be efficiently produced.

Description

TECHNICAL FIELD

[0001] The present application relates to a yttrium fluoride-based sprayed film for use in a member for a semiconductor manufacturing apparatus used in a semiconductor manufacturing process, a method for manufacturing the same, and a spraying member. BACKGROUND

[0002] In a plasma etching apparatus used in a semiconductor manufacturing process, a wafer as a processed object is treated in a plasma atmosphere of a highly corrosive fluorine-based, chlorine-based, or halogen-based gas. As the fluorine-based gas, SF6, CF4, CHF3, C1F3, HF, NF3, or the like is used, and as the chlorine-based gas, C12, BCl3, HC1, CCl4, SiCl4, or the like is used.

[0003] In the production of a member for a semiconductor manufacturing apparatus of a plasma etching apparatus that is exposed to a highly corrosive gas plasma atmosphere, an atmospheric plasma spray (APS) in which a raw material such as a rare earth compound is supplied in the form of a powder, a suspension plasma spray (SPS) in which a raw material is sprayed in the form of a slurry in which the raw material is dispersed in a dispersion medium, or the like is generally performed to form a corrosion-resistant sprayed film on the surface of a base material.

[0004] In recent years, with the development of integration of semiconductors and the development of miniaturization of wiring, particles that are peeled from a sprayed film in plasma etching cause a decrease in yield in semiconductor manufacturing. The wiring gradually becomes 10 nm or less, and it is necessary to further suppress the amount of particle generation.

[0005] For example, in Japanese Patent Application Publication No. 2017-190475 (Patent Literature 1), a yttrium fluoride sprayed film containing YF3 that has a small amount of particle generation is described. In addition, in Japanese Patent Application Publication No. 2004-197181 (Patent Literature 2), a yttrium fluoride sprayed film is obtained by spraying a raw material in which crystalline YF3 is used. Further, in Japanese Patent Application Publication No. 2018-053356 (Patent Literature 3), it is described that a yttrium fluoride sprayed film containing a YF3 crystal phase of an orthorhombic crystal and a YOF crystal phase is obtained by plasma spraying a mixed raw material containing YF3 of an orthorhombic crystal and YOF in a raw material.

[0006] On the other hand, in Japanese Patent Application Publication No. 2019-192701 (Patent Literature 4), it is described that the smaller the average crystallite size of the film, the more the generation of foreign matter can be suppressed.

[0007] PRIOR ART DOCUMENTS

[0008] PATENT LITERATURE

[0009] Patent Literature 1: Japanese Patent Application Publication No. 2017-190475

[0010] Patent Literature 2: Japanese Patent Application Laid-Open (JP-A) No. 2004-197181

[0011] Patent Literature 3: Japanese Patent Application Laid-Open (JP-A) No. 2018-053356

[0012] Patent Literature 4: Japanese Patent Application Laid-Open (JP-A) No. 2019-192701 SUMMARY

[0013] PROBLEMS TO BE SOLVED BY THE INVENTION

[0014] However, as for YF3 confirmed in the yttrium fluoride sprayed film described in Patent Literature 1, it is YF3 other than the orthorhombic system (for example, hexagonal system which is a high-temperature stable phase). The corrosion-resistant film used in the member for a semiconductor manufacturing apparatus is exposed to a halogen gas plasma in plasma etching, and if YF3 crystal phase other than the orthorhombic system is contained in the corrosion-resistant film, the YF3 crystal phase is phase-transformed from the high-temperature stable phase to the orthorhombic system which is a low-temperature stable phase due to plasma heat, and cracks due to the influence of volume change of the film caused by the phase transformation are generated, and particles are sometimes generated, and there is room for improvement.

[0015] In addition, in the atmospheric pressure spraying described in Patent Literature 2, YF3 crystal phase other than the orthorhombic system in the yttrium fluoride sprayed film is not completely eliminated, and in addition, in order to eliminate YF3 crystal phase other than the orthorhombic system, heat treatment of 200 to 500°C to the sprayed film is required, and the process is increased. Furthermore, even if the heat treatment is performed, the hardness of the sprayed film is not sufficiently improved.

[0016] Furthermore, even in the plasma spraying described in Patent Literature 3, YF3 crystal phase other than the orthorhombic system in the yttrium fluoride sprayed film is not completely eliminated, and in order to eliminate YF3 crystal phase other than the orthorhombic system, heat treatment of 200 to 500°C to the sprayed film is required, and similarly, the process is increased.

[0017] On the other hand, if the fact described in Patent Literature 4 that the smaller the average crystallite size of the film is, the more the generation of foreign matter can be suppressed is taken into consideration, as for the film in which YF3 crystal phase other than the orthorhombic system is eliminated by heat treatment of the yttrium fluoride sprayed film obtained by the plasma spraying described in Patent Literature 2 and Patent Literature 3, the crystallite of the film grows due to the heat treatment. That is, the average crystallite size of the yttrium fluoride sprayed film which does not contain YF3 other than the orthorhombic system obtained by the process of heat treatment is large, and the generation of foreign matter cannot be suppressed, and thus there is room for improvement.

[0018] In the case of yttrium-based corrosion-resistant films for members for semiconductor manufacturing apparatuses, yttrium fluoride-based spray films have gradually replaced yttrium oxide-based spray films in order to suppress the generation of yttrium-based particles resulting from reactions with corrosive halogen-based gas plasma. However, even with yttrium fluoride-based spray films, the film hardness is low, and the films are weak against plasma etching using halogen-based gas plasma, and the suppression of particle generation is not sufficient. In addition, in the case where YF3 crystal phases are contained in yttrium fluoride-based spray films, if YF3 crystal phases other than the orthorhombic system (for example, hexagonal system which is a high-temperature stable phase) exist, the YF3 crystal phases other than the orthorhombic system are phase-transformed to the orthorhombic system which is a low-temperature stable phase due to plasma heat if the film is exposed to halogen-based gas plasma at the time of plasma etching, and cracks are generated due to the volume change of the film at this time, and particles are generated, which is a problem.

[0019] The present application has been achieved in view of the above-described actual circumstances, and aims to provide, as a high-corrosion-resistant yttrium fluoride-based spray film containing YF3 crystal phases, a yttrium fluoride-based spray film which is used in members for semiconductor manufacturing apparatuses, generates a small amount of particles when exposed to halogen-based gas plasma, a spray member provided with such a spray film, and a method capable of efficiently manufacturing such a spray film.

[0020] Means for solving the problem

[0021] The present inventors have intensively studied in order to solve the above-described problem, and as a result, have found that a yttrium fluoride-based spray film containing YF3 crystal phases of the orthorhombic system, not containing YF3 crystal phases other than the orthorhombic system, and having a Vickers hardness of 350 or more significantly suppresses the generation of yttrium-based particles in a halogen-based gas plasma atmosphere, and a spray member in which such a spray film is formed on a substrate is excellent as a member for a semiconductor manufacturing apparatus, such a spray film can be formed by plasma spraying of a spray material, and even if a heat treatment is not performed on the spray film, a yttrium fluoride-based spray film having a high film hardness can be manufactured, and the present application has been completed.

[0022] Therefore, the present application provides the following yttrium fluoride-based spray film, spray member, and method for manufacturing a yttrium fluoride-based spray film.

[0023] 1. A yttrium fluoride-based spray film, characterized by containing YF3 crystal phases of the orthorhombic system, not containing YF3 crystal phases other than the orthorhombic system, and having a Vickers hardness of 350 or more.

[0024] 2. The yttrium fluoride-based spray film according to 1, characterized by further containing yttrium oxyfluoride crystal phases.

[0025] 3. The yttrium fluoride-based sprayed coating according to 2, wherein the yttrium oxyfluoride is one or more selected from the group consisting of Y5O4F7, Y6O5F8, Y7O6F9 and YOF.

[0026] 4. The yttrium fluoride-based sprayed coating according to any one of 1 to 3, which does not contain a Y2O3 crystal phase.

[0027] 5. The yttrium fluoride-based sprayed coating according to any one of 1 to 4, which has a film thickness of 10 to 500 μm.

[0028] 6. A sprayed coating which is the yttrium fluoride-based sprayed coating according to any one of 1 to 5 formed on a substrate, wherein the sprayed coating having a prescribed surface area is immersed in ultrapure water together with the substrate, ultrasonic cleaning is performed on the sprayed coating for 30 minutes using an output power of 200 W, the sprayed coating and the substrate are taken out of the cleaning solution and dried, next, the sprayed coating is immersed in ultrapure water together with the substrate, ultrasonic treatment is performed on the sprayed coating for 15 minutes using an output power of 200 W, the sprayed coating and the substrate are taken out of the treatment solution, next, 2 ml of a 5.3 N (5.3 normal) aqueous nitric acid solution is added to 20 ml of the treatment solution, and yttrium-based particles that have fallen off from the sprayed coating are dissolved in the treatment solution, and next, when the amount of yttrium contained in the treatment solution is quantified by ICP emission spectrometry, a value equivalent to the mass of yttrium in the yttrium-based particles per the prescribed surface area is 1 μg / cm 2 The following.

[0029] 7. A sprayed member comprising a substrate and the yttrium fluoride-based sprayed coating according to any one of 1 to 6 formed on the substrate.

[0030] 8. The sprayed member according to 7, wherein the yttrium fluoride-based sprayed coating is a single-layer structure coating.

[0031] 9. The sprayed member according to 7 or 8, which is for a semiconductor manufacturing device.

[0032] 10. A method for producing a yttrium fluoride-based sprayed coating, which is a method for producing the yttrium fluoride-based sprayed coating according to any one of 1 to 6, comprising the step of plasma spraying a sprayed powder containing a YF3 crystal phase of an orthorhombic system and not containing a YF3 crystal phase other than the orthorhombic system.

[0033] 11. The production method according to 10, wherein the plasma spraying is atmospheric plasma spraying.

[0034] 12. The manufacturing method according to 11, characterized in that the spraying distance in the above-mentioned atmospheric plasma spraying process is 50-90 mm.

[0035] 13. The manufacturing method according to any one of 10 to 12, characterized in that, in the plasma spraying process described above, a mixed gas comprising argon and hydrogen is used as the plasma gas.

[0036] 14. The manufacturing method according to 13, characterized in that the supply rate of the argon gas is 40 NLPM or higher.

[0037] 15. The manufacturing method according to 13 or 14, characterized in that the supply rate of the hydrogen gas is 8 NLPM or higher.

[0038] 16. The manufacturing method according to any one of 10 to 15, characterized in that the oxygen content of the above-mentioned spray powder is 7% by mass or less.

[0039] 17. The manufacturing method according to any one of 10 to 16, characterized in that the yttrium-based crystal phase contained in the above-mentioned spray powder contains only the orthorhombic YF3 crystal phase or only the orthorhombic YF3 crystal phase and the yttrium oxyfluoride crystal phase, and the above-mentioned spray powder is granulated unfired powder or granulated sintered powder.

[0040] 18. The manufacturing method according to 17, characterized in that the yttrium oxyfluoride is selected from one or more of Y5O4F7, Y6O5F8 and Y7O6F9.

[0041] 19. The manufacturing method according to any one of 10 to 16, characterized in that the yttrium-based crystal phase contained in the above-mentioned spray powder includes only the orthorhombic YF3 crystal phase and Y2O3 crystal phase, and the above-mentioned spray powder is granulated and unfired powder.

[0042] 20. The manufacturing method according to any one of 10 to 19, characterized in that it does not include the step of heat-treating the yttrium fluoride spray coating formed by plasma spraying.

[0043] The effects of the invention

[0044] According to the present invention, a yttrium fluoride-based spray coating film with high coating hardness and low particle quantity generated when exposed to halogen-based gas plasma can be provided. Such a spray coating film is excellent as a spray coating film formed in components of semiconductor manufacturing apparatus used in semiconductor manufacturing processes. In addition, according to the present invention, such a yttrium fluoride-based spray coating film can be manufactured with high efficiency. Attached Figure Description

[0045] Figure 1 The X-ray diffraction profile of the sprayed film obtained in Example 1 is shown.

[0046] Figure 2 The X-ray diffraction profile of the sprayed coating obtained in Comparative Example 1 was compared. DETAILED DESCRIPTION

[0047] The present application is described in more detail below.

[0048] The sprayed coating of the present application is a yttrium fluoride-based sprayed coating containing an orthorhombic YF3crystal phase, and is suitable for use in a member for a semiconductor manufacturing apparatus used in a semiconductor manufacturing process. The yttrium fluoride-based sprayed coating of the present application does not contain a YF3crystal phase other than the orthorhombic crystal phase (e.g., a hexagonal YF3crystal phase which is a high-temperature stable phase, etc.). The orthorhombic YF3crystal phase is sometimes referred to as β-YF3, and the hexagonal YF3crystal phase is sometimes referred to as α-YF3.

[0049] The diffraction peak of the YF3crystal phase belonging to the orthorhombic crystal phase is not particularly limited, and for example, contains a diffraction peak attributed to the (101) plane of the crystal lattice, which is usually detected at around 2θ = 24.5°. In addition, the diffraction peak of the YF3crystal phase other than the orthorhombic crystal phase is not particularly limited, and in the case of the diffraction peak of the YF3crystal phase belonging to the hexagonal crystal phase, for example, contains a diffraction peak attributed to the (111) plane of the crystal lattice, which is usually detected at around 2θ = 29.3°, by the X-ray diffraction method (characteristic X-ray: Cu-Kα), in the range of diffraction angle 2θ = 10 to 70°.

[0050] The average crystallite size of the sprayed coating of the present application, which is obtained from the half-value width of the diffraction peak of the YF3crystal phase belonging to the orthorhombic crystal phase, is preferably 70 nm or less, more preferably 60 nm or less, further preferably 50 nm or less, and particularly preferably 40 nm or less. If the average crystallite size is 70 nm or less, the change in the crystallite size after plasma etching of the film surface with a halogen-based gas plasma is small, and the generation of yttrium-based particles is reduced. On the other hand, the average crystallite size is not particularly limited, and is usually 5 nm or more.

[0051] The yttrium fluoride-based sprayed coating of the present application particularly does not contain a hexagonal YF3crystal phase which is a high-temperature stable phase, and therefore, in plasma etching using a corrosive halogen-based gas used in a semiconductor manufacturing process or the like, there is no volume change of the film caused by a phase change from the hexagonal YF3crystal phase to the orthorhombic YF3crystal phase due to plasma heat, and the volume change is suppressed throughout the film, and therefore, the generation of yttrium-based particles in a halogen-based gas plasma atmosphere is small.

[0052] The Vickers hardness of the yttrium fluoride-based sprayed coating film of the present application is 350 or more, preferably 400 or more, more preferably 450 or more, and further preferably 480 or more. If the Vickers hardness is 350 or more, it becomes difficult to plasma-etch the coating film surface with a halogen-based gas plasma, and the corrosion resistance is further improved. On the other hand, the higher the Vickers hardness, the better, and it is usually 1000 or less. If the Vickers hardness is 1000 or less, it becomes difficult to peel off from the substrate. It should be noted that the Vickers hardness can be measured in accordance with JIS Z2244.

[0053] The yttrium fluoride-based sprayed coating film contains yttrium (Y) and fluorine (F) as essential constituent elements, and can contain other elements such as oxygen (O) and the like. In addition, a small amount of rare earth (lanthanoid) elements other than yttrium (Y) can be contained, and the metal elements contained in the yttrium fluoride-based sprayed coating film are preferably only yttrium (Y). It should be noted that the yttrium fluoride-based sprayed coating film can contain elements in an impurity amount.

[0054] The yttrium fluoride-based sprayed coating film of the present application can contain yttrium oxyfluoride crystal phase. The sprayed coating film containing yttrium oxyfluoride crystal phase is advantageous in that the amount of yttrium-based particles generated when exposed to a corrosive halogen-based gas plasma becomes less. As the yttrium oxyfluoride constituting the yttrium oxyfluoride crystal phase, one or more selected from the group consisting of Y5O4F7, Y6O5F8, Y7O6F9, and YOF (Y1O1F1) is preferable, and in particular, in the case of containing YOF, it is preferable that the yttrium oxyfluoride be YOF and one or more selected from the group consisting of Y5O4F7, Y6O5F8, and Y7O6F9. On the other hand, the yttrium fluoride-based sprayed coating film of the present application preferably does not contain Y2O3 crystal phase.

[0055] For the yttrium fluoride-based sprayed coating film of the present application, the film thickness is preferably 10 μm or more from the viewpoint of durability against corrosion caused by a halogen-based gas plasma. More preferably, the film thickness is 30 μm or more, and further preferably 50 μm or more. On the other hand, the film thickness of the sprayed coating film is preferably 500 μm or less. If the thickness of the coating film is 500 μm or less, it becomes more difficult to peel off from the substrate. More preferably, the film thickness is 400 μm or less, and further preferably 300 μm or less.

[0056] For the yttrium fluoride-based sprayed coating film of the present application, the surface roughness Ra is preferably 8 μm or less, more preferably 7 μm or less, and further preferably 6 μm or less from the viewpoint of further suppressing the generation of particles caused by a halogen-based gas plasma. In addition, the surface roughness Ra is not particularly limited from the same viewpoint, and is usually 0.1 μm or more.

[0057] The fluorinated yttrium-based sprayed coating film of the present application is less likely to generate yttrium-based particles when exposed to a halogen-based gas plasma, and the generation of particles after the fluorinated yttrium-based sprayed coating film is just manufactured is also very small. In the case of the fluorinated yttrium-based sprayed coating film of the present application, for example, in a state formed on a substrate, the sprayed coating film is evaluated by

[0058] (1) The sprayed coating film having a prescribed surface area is immersed in ultrapure water together with the substrate, ultrasonic cleaning is performed for 30 minutes at an output power of 200 W, the sprayed coating film is taken out of the cleaning liquid together with the substrate and dried,

[0059] (2) The sprayed coating film is immersed in ultrapure water together with the substrate, ultrasonic treatment is performed for 15 minutes at an output power of 200 W, the sprayed coating film is taken out of the treatment liquid together with the substrate,

[0060] (3) 2 ml of 5.3 N nitric acid aqueous solution is added to every 20 ml of the treatment liquid, and yttrium-based particles that have fallen off from the sprayed coating film are dissolved in the treatment liquid,

[0061] (4) When the generation of particles is evaluated as a value equivalent to the mass of yttrium in the yttrium-based particles per unit of the prescribed surface area of the sprayed coating film (the surface area of the sprayed coating film to be evaluated) by a method for quantifying the amount of yttrium contained in the treatment liquid by ICP emission spectrometry, it is preferable that the value be 1 μg / cm 2 or less. If the value exceeds 1 μg / cm 2 , the generation of particles is excessive, and it is likely that the use in a plasma etching device is not tolerated. The amount of Y particles is more preferably 0.8 μg / cm 2 or less, and further preferably 0.6 μg / cm 2 or less.

[0062] By forming the fluorinated yttrium-based sprayed coating film of the present application on a substrate, a sprayed member having a substrate and a fluorinated yttrium-based sprayed coating film, particularly a sprayed member in which a fluorinated yttrium-based sprayed coating film is directly formed on a substrate, can be manufactured, and such a sprayed member is preferably used as a sprayed member for a semiconductor manufacturing device. In the present application, the fluorinated yttrium-based sprayed coating film can be a single-layer structure film or a multi-layer structure film, and is preferably a single-layer structure film.

[0063] The material of the substrate is not particularly limited, and examples include metals such as stainless steel, aluminum, nickel, chromium, zinc, and alloys thereof, inorganic compounds (ceramics) such as alumina, zirconia, aluminum nitride, silicon nitride, silicon carbide, and quartz glass, and carbon, and the preferable material is selected depending on the use of the sprayed member (for example, uses such as for a semiconductor manufacturing device). For example, in the case of a substrate of aluminum metal or an aluminum alloy, a substrate subjected to acid-resistant aluminum treatment having acid resistance is preferable. The shape of the substrate is not particularly limited, and examples include substrates having a flat plate shape, a cylindrical shape, and the like.

[0064] For the production of the yttrium fluoride-based sprayed coating film of the present application, a method of plasma spraying the sprayed powder (sprayed particles) as the sprayed material is preferably applied. In the present application, as the yttrium fluoride-based sprayed coating film having high hardness of 350 or more and high corrosion resistance with a small amount of yttrium-based particles generated when exposed to a halogen-based gas plasma, which is a yttrium fluoride-based sprayed coating film containing YF3crystal phase of an orthorhombic system, a yttrium fluoride-based sprayed coating film not containing YF3crystal phase other than the orthorhombic system can be produced.

[0065] As the plasma spraying, atmospheric plasma spraying (APS), suspension plasma spraying (SPS), and the like can be exemplified, and if cost reduction and mass production are taken into consideration, atmospheric plasma spraying is preferable. As the plasma spraying, in the case where atmospheric plasma spraying is applied, the spraying distance is preferably 90 mm or less, more preferably 85 mm or less, and further preferably 80 mm or less. As the spraying distance is shortened, the adhesion efficiency of the sprayed coating film is improved, and in addition, the hardness is increased and the porosity is reduced. On the other hand, the spraying distance is not particularly limited, and is preferably 50 mm or more, more preferably 55 mm or more, and further preferably 60 mm or more. Note that the spraying distance is the distance from the nozzle of the spraying gun to the target on which the sprayed coating film is formed.

[0066] As the plasma gas used for forming plasma in the plasma spraying, a single gas selected from one of argon (Ar), hydrogen (H2), helium (He), and nitrogen (N2), or a mixed gas of two or more kinds, and the like can be exemplified. A mixed gas containing argon and hydrogen is preferable, and is not particularly limited. The mixed gas containing argon and hydrogen can contain other gases such as hydrogen, helium, and the like.

[0067] In the case where argon is used as the plasma gas, the supply rate of argon is not particularly limited, and is preferably 40 NLPM (Normal Liter Per Minute) or more, and more preferably 42 NLPM or more. The higher the supply rate of argon, the higher the speed of the sprayed particles, and the adhesion strength of the sprayed coating film formed is improved, which is advantageous in this respect. On the other hand, it is preferable that the supply rate of argon be higher, but is usually 100 NLPM or less. If the supply rate of argon is 100 NLPM or less, the load applied to the spraying device can be reduced, which is also advantageous in terms of cost.

[0068] The supply rate of hydrogen gas is not particularly limited in the case of using hydrogen gas as the plasma gas, and is preferably 8 NLPM or more, and more preferably 10 NLPM or more. The higher the supply rate of hydrogen gas, the more heat is applied to the sprayed particles, and the hardness of the sprayed coating film formed is improved, which is advantageous in this respect. On the other hand, the supply rate of hydrogen gas is preferably higher, but is usually 20 NLPM or less. If the supply rate of hydrogen gas is 20 NLPM or less, the load applied to the spraying device can be reduced, which is advantageous in terms of cost.

[0069] The applied power in the plasma spraying is not particularly limited, and is preferably 35 kW or more, and more preferably 40 kW or more. On the other hand, the applied power is not particularly limited, and is preferably 85 kW or less, and more preferably 60 kW or less. The current value is not particularly limited, and is preferably 600 A or more, and more preferably 620 A or more. The higher the current value, the higher the speed and temperature of the sprayed particles, and the hardness and adhesion strength of the coating film formed are improved, which is advantageous in this respect. On the other hand, the current value is preferably higher, but is usually 1000 A or less. If the current value is 1000 A or less, the load applied to the spraying device can be reduced.

[0070] The temperature of the substrate at the time of spraying is preferably 100°C or more, more preferably 130°C or more, and further preferably 150°C or more. The higher the temperature, the more the bonding between the substrate and the sprayed coating film formed is enhanced, and the sprayed coating film can be made denser. In addition, the higher the temperature, the more the quenching stress is generated, and the hardness of the sprayed coating film formed is improved.

[0071] On the other hand, the temperature of the substrate, or the substrate and the sprayed coating film formed on the substrate at the time of spraying is preferably 300°C or less, more preferably 270°C or less, and further preferably 250°C or less. The lower the temperature, the more the damage and deformation of the substrate caused by heat can be prevented. In addition, the lower the temperature, the more the generation of thermal stress can be suppressed, and the peeling between the substrate and the sprayed coating film formed can be prevented. It is noted that this temperature can be achieved by controlling the cooling capacity.

[0072] The supply rate of the sprayed powder and other spraying conditions in the plasma spraying are not particularly limited, and the conditions known in the art can be used, and can be appropriately set depending on the substrate, the sprayed material, the use of the sprayed member, and the like.

[0073] As the spraying powder used in the production of the yttrium fluoride-based sprayed coating film of the present application, a spraying powder containing an orthorhombic YF3 crystal phase and no YF3 crystal phase other than the orthorhombic crystal phase is preferred. The spraying powder contains yttrium (Y) and fluorine (F) as essential constituent elements, and can contain other elements such as oxygen (O) and the like. In addition, a small amount of rare earth (lanthanoid) elements other than yttrium (Y) can be contained, and it is preferred that the only metal element contained in the spraying powder be yttrium (Y). Note that the spraying powder can contain elements in impurity amounts.

[0074] The oxygen content of the spraying powder is preferably 7% by mass or less. If the oxygen content is 7% by mass or less, even if plasma spraying is performed in an atmospheric atmosphere, a yttrium fluoride-based sprayed coating film containing an orthorhombic YF3 crystal phase and no YF3 crystal phase other than the orthorhombic crystal phase can be easily produced. The oxygen content is more preferably 6.5% by mass or less. On the other hand, the oxygen content is not particularly limited, and is 0% by mass in the case where the spraying powder contains no oxygen, and is greater than 0% by mass in the case where the spraying powder contains oxygen, and is preferably 1% by mass or more, and more preferably 2% by mass or more.

[0075] In the production of the yttrium fluoride-based sprayed coating film of the present application, it is preferred to use a spraying powder in which the yttrium-based crystal phase contained in the spraying powder contains only an orthorhombic YF3 crystal phase, or contains only an orthorhombic YF3 crystal phase and a yttrium oxyfluoride crystal phase. Of these, as the yttrium oxyfluoride constituting the yttrium oxyfluoride crystal phase, one or more selected from the group consisting of Y5O4F7, Y6O5F8 and Y7O6F9 is preferred. In addition, it is also preferred to use a spraying powder in which the yttrium-based crystal phase contained in the spraying powder contains only an orthorhombic YF3 crystal phase and a Y2O3 crystal phase. Of these, the Y2O3 crystal phase is not particularly limited, and is preferably cubic.

[0076] The spraying powder is preferably a granulated, un-sintered powder or a granulated, sintered powder. Of these, the so-called granulated, un-sintered powder means a product in which a powder obtained by granulation is used as a spraying powder without sintering; and the so-called granulated, sintered powder means a product in which a powder obtained by granulation is sintered to produce a spraying powder.

[0077] The particle diameter of the spraying powder (spraying particles) is not particularly limited, and the average particle diameter D50 is preferably 80 μm or less, more preferably 60 μm or less, and further preferably 50 μm or less. In the present application, the average particle diameter D50 is the cumulative 50% (median diameter) in the particle diameter distribution on a volume basis. The smaller the particle diameter of the spraying particles, the smaller the diameter of the molten particles formed by the collision of the molten particles with the substrate at the time of spraying, and the denser the sprayed coating film formed thereby. On the other hand, the average particle diameter D50 is preferably 10 μm or more, more preferably 15 μm or more, and further preferably 18 μm or more. The larger the particle diameter of the spraying particles, the greater the momentum of the molten particles, and the easier it becomes to form a coating film by the collision of the molten particles with the substrate and the coating film formed on the substrate.

[0078] In the method for producing the yttrium fluoride-based sprayed coating film of the present application, the step of heat-treating the yttrium fluoride-based sprayed coating film formed by plasma spraying (note that the heat treatment includes, for example, an annealing treatment performed to eliminate residual stress, etc.) is not necessarily required, and a good yttrium fluoride-based sprayed coating film having a high coating film hardness, which contains an orthorhombic YF3 crystal phase and does not contain YF3 crystal phases other than the orthorhombic YF3 crystal phase, can be obtained even without heat treatment.

[0079] When the sprayed coating film is formed on the substrate, roughening treatment is preferably performed, for example, acetone degreasing is performed on the surface of the substrate on which the sprayed coating film is to be formed, and roughening treatment is performed using, for example, a corundum abrasive material to increase the surface roughness Ra of the surface. By performing roughening treatment on the substrate, peeling of the coating film due to a difference in the coefficient of thermal expansion between the sprayed coating film and the substrate after the spraying work can be effectively suppressed. The degree of roughening treatment can be appropriately adjusted depending on the material of the substrate, etc.

[0080] In particular, when the sprayed coating film is directly formed on the substrate, as described above, the surface roughness Ra of the surface of the substrate on which the sprayed coating film is to be formed is increased, and further, the temperature of the substrate is set to the above-mentioned temperature, and plasma spraying is performed, whereby peeling is more difficult to occur, and a sprayed coating film having a higher hardness and being denser can be formed. In this case, the surface roughness Ra of the formed sprayed coating film tends to increase, and therefore, by performing surface processing such as mechanical polishing (flat surface grinding, inner cylinder processing, mirror surface processing, etc.), blasting treatment using fine beads, hand polishing using a diamond pad, or the like to reduce the surface roughness Ra, a smooth sprayed coating film which is more difficult to peel, has a higher hardness, is denser, and has a low surface roughness Ra can be formed.

[0081] Example

[0082] Hereinafter, examples and comparative examples will be shown, and the present application will be specifically described, but the present application is not limited to the following examples.

[0083] [Example 1]

[0084] Acetone degreasing was performed on the surface of a 20 mm square (5 mm thick) A5052 aluminum alloy substrate, and roughening treatment was performed on one surface of the substrate using a grinding material of corundum. The temperature of the substrate was set to 170°C, and a granulated and sintered powder having an average particle diameter D50 of 30 μm, an oxygen content of 2.3 mass%, and a crystal phase composed of an orthorhombic YF3 crystal phase and a Y5O4F7 crystal phase was used to form a yttrium fluoride-based sprayed coating film (sprayed member) having a film thickness of 200 μm on the substrate by atmospheric plasma spraying.

[0085] For the obtained sprayed coating, the crystal phase was identified by X-ray diffraction (XRD) and the crystalline constitution was analyzed. In addition, the film thickness, surface roughness Ra, Vickers hardness, and average crystallite size were measured. Further, the corrosion resistance of the sprayed coating and the amount of yttrium-based particles generated were evaluated using the obtained sprayed coating. The results are shown in Table 1. Note that the details of each of the measurement, analysis, and evaluation will be described later. In addition, the XRD profile is shown in Figure 1

[0086] As for the atmospheric plasma spraying, the spraying machine F4 of Eriko Metec Corporation was used, and was performed in an atmospheric atmosphere at normal pressure. The spraying distance was adjusted to 80 mm, the argon flow rate was adjusted to 42 NLPM, the hydrogen flow rate was adjusted to 12 NLPM, and the applied power was adjusted to 44 kW, and the sprayed coating was formed. The spraying conditions of the atmospheric plasma spraying in which the sprayed coating was formed are shown in Table 2.

[0087] [Example 2]

[0088] A yttrium fluoride-based sprayed coating (sprayed member) having a film thickness of 200 μm was obtained in the same manner as in Example 1 except that a granulated and un-fired powder having an average particle diameter D50 of 35 μm, an oxygen content of 2.7 mass%, and a crystal phase composed of YF3 crystal phase of orthorhombic system and Y2O3 crystal phase of cubic system was used. For the obtained sprayed coating, the same measurement, analysis, and evaluation as in Example 1 were performed. The results are shown in Table 1. In addition, the spraying conditions of the atmospheric plasma spraying in which the sprayed coating was formed are shown in Table 2.

[0089] [Example 3]

[0090] A yttrium fluoride-based sprayed coating (sprayed member) having a film thickness of 100 μm was obtained in the same manner as in Example 1 except that a granulated and fired powder having an average particle diameter D50 of 30 μm, an oxygen content of 6.3 mass%, and a crystal phase composed of YF3 crystal phase of orthorhombic system and Y5O4F7 crystal phase was used. For the obtained sprayed coating, the same measurement, analysis, and evaluation as in Example 1 were performed. The results are shown in Table 1. In addition, the spraying conditions of the atmospheric plasma spraying in which the sprayed coating was formed are shown in Table 2.

[0091] [Comparative Example 1]

[0092] ​The surface of a 20 mm square (5 mm thick) A5052 aluminum alloy substrate was degreased with acetone, and for one side of the substrate, a roughened surface was formed using a corundum abrasive material. The substrate was heated to 90°C, and for the substrate, a granulated and sintered powder identical to that used in Example 1 was used to form a yttrium fluoride-based sprayed film (sprayed member) by atmospheric plasma spraying to a thickness of 200 μm. The same measurements, analyses, and evaluations as in Example 1 were performed on the resulting sprayed film. The results are shown in Table 1. In addition, the XRD profile is shown in Figure 2

[0093] For the atmospheric plasma spraying, an Elionix Co., Ltd. spray machine F4 was used, and the spraying was performed in an atmospheric atmosphere at normal pressure. The spraying distance was adjusted to 120 mm, the argon flow rate was adjusted to 42 NLPM, the hydrogen flow rate was adjusted to 6 NLPM, and the applied power was adjusted to 36 kW, and the sprayed film was formed. The spraying conditions for the atmospheric plasma spraying in which the sprayed film was formed are shown in Table 2.

[0094] [Comparative Example 2]

[0095] Except for using a granulated powder identical to that used in Example 2, the same as in Comparative Example 1 was performed to form a yttrium fluoride-based sprayed film (sprayed member) to a thickness of 200 μm. The same measurements, analyses, and evaluations as in Example 1 were performed on the resulting sprayed film. The results are shown in Table 1. In addition, the spraying conditions for the atmospheric plasma spraying in which the sprayed film was formed are shown in Table 2.

[0096] [Comparative Example 3]

[0097] Except for using a granulated and sintered powder having an average particle size D50 of 30 μm, an oxygen content of 9.2 mass%, and a crystal phase consisting of a Y5O4F7 crystal phase, the same as in Comparative Example 1 was performed to form a yttrium fluoride-based sprayed film (sprayed member) to a thickness of 70 μm. The same measurements, analyses, and evaluations as in Example 1 were performed on the resulting sprayed film. The results are shown in Table 1. In addition, the spraying conditions for the atmospheric plasma spraying in which the sprayed film was formed are shown in Table 2.

[0098] [Comparative Example 4]

[0099] Except for using a granulated and sintered powder having an average particle size D50 of 30 μm, an oxygen content of 12.8 mass%, and a crystal phase consisting of a YOF crystal phase, the same as in Comparative Example 1 was performed to form a yttrium fluoride-based sprayed film (sprayed member) to a thickness of 40 μm. The same measurements, analyses, and evaluations as in Example 1 were performed on the resulting sprayed film. The results are shown in Table 1. In addition, the spraying conditions for the atmospheric plasma spraying in which the sprayed film was formed are shown in Table 2.

[0100] [Table 1]​

[0101]

[0102] [Table 2]

[0103]

[0104] [X-ray Diffraction (XRD)]

[0105] The measurement was performed using an X-ray diffraction measuring device X'Pert PRO / MPD manufactured by Malvern Panalytical, Inc., and the crystal phase was identified using an analysis software HighScore Plus manufactured by Malvern Panalytical, Inc. The measurement conditions were characteristic X-ray: Cu-Ka (tube voltage 45 kV, tube current 40 mA), scanning range: 2 theta = 5 to 70°, step size: 0.0167113°, time per step: 13.970 seconds, scanning speed: 0.151921° / second.

[0106] [Thickness of Film]

[0107] The measurement was performed using a eddy current film thickness meter LH-300J manufactured by Kett Scientific Corporation.

[0108] [Surface roughness (Ra)]

[0109] The measurement was performed using a surface roughness meter HANDYSURF E-35A manufactured by Tokyo Denshoku Co., Ltd.

[0110] [Vickers Hardness]

[0111] The surface of the coated test piece was processed to mirror surface (surface roughness Ra = 0.1 μm), and the measurement was performed using a micro Vickers hardness tester HMV-G manufactured by Shimadzu Corporation with a load of 300 gf (2.942 N) and a holding time of 10 seconds, using the surface of the test piece on which the mirror surface was processed, and the evaluation was performed as an average value of 5.

[0112] [Average crystallite size]

[0113] The X-ray profile obtained by measuring 2θ up to 10° to 100° at a fixed incident angle of 1.5° was obtained by X-ray diffraction method. For the obtained X-ray profile, index notation of each diffraction peak was performed, and for the diffraction peaks of the (101) plane, (020) plane and (210) plane of the YF3 crystal phase belonging to the orthorhombic system in the case of Examples 1 to 3, and for the diffraction peaks of the (002) plane, (110) plane and (111) plane of the YF3 crystal phase belonging to the hexagonal system in the case of Comparative Examples 1 and 2, the half-value width was calculated, and the average crystallite size was calculated by Williamson-Hall method.

[0114] [evaluation test of corrosion resistance]

[0115] The surface of the sprayed coating film (surface coating film) of the sprayed member test piece was mirror finished (Ra = 0.1 μm), and after forming a portion covered with a masking tape and a film exposed portion, the test piece was set in a reactive ion plasma test device, and was exposed to plasma under conditions of plasma output power 440 W, gas species CF4+O2 (20 vol%), flow rate 20 seem, gas pressure 5 Pa, 8 hours. For the test piece exposed to plasma, using a stylus surface shape measuring device Dektak 3030 manufactured by Bruker Nano, the height of the step difference due to corrosion was measured between the portion covered with a masking tape and the film exposed portion, the average value of 4 points of the measurement site was calculated, and the corrosion resistance was evaluated. In the evaluation using this test, the average value of the height of the step difference (average step difference) is preferably 4.0 μm or less. If the average step difference exceeds 4.0 μm, sufficient plasma etching resistance cannot be sometimes exerted when used in a plasma etching device. The average step difference is more preferably 3.5 μm or less, and further preferably 3.3 μm or less.

[0116] [evaluation test of y particle generation amount]

[0117] For the test piece having a square of 20 mm (4 cm 2The surface area of ​​the coated component was used to form a test piece for spraying. For the test piece, the coated film was immersed in ultrapure water with the side facing the water surface, and then ultrasonically cleaned (output power 200W, cleaning time 30 minutes) to remove post-spraying contaminants. Next, after drying the test piece, it was placed in a 100ml polyethylene bottle with 20ml of ultrapure water, and ultrasonically treated (output power 200W, cleaning time 15 minutes) with the coated film facing the bottom of the polyethylene bottle. After ultrasonic treatment, the test piece was removed, and 2ml of 5.3N nitric acid aqueous solution was added to the treatment solution to dissolve the yttrium particles contained in the treatment solution. The amount of Yttrium in the treatment solution was determined by ICP-N (Inductively Coupled Phosphorus) spectrophotometry, which was used as the unit surface area (4cm²) of the coated film on the test piece. 2 The quality of Y is used to evaluate it.

[0118] It was found that, for the yttrium fluoride spray coatings of Examples 1-3, which contain orthorhombic YF3 crystal phases and do not contain YF3 crystal phases other than orthorhombic, the amount of yttrium particles generated in the Y particle generation evaluation test was much less than that of the spray coatings of Comparative Examples 1-4. Furthermore, it was found that, for the yttrium fluoride spray coatings of Examples 1-3, the average step height difference after plasma etching in the corrosion resistance evaluation test was smaller than that of Comparative Examples 1-4. Therefore, it was found that the yttrium fluoride spray coating of the present invention is an excellent spray coating suitable for use in components for semiconductor manufacturing apparatuses.

Claims

1. A yttrium fluoride-based spray coating, characterized in that, It includes the orthorhombic YF3 crystal phase and the yttrium oxyfluoride crystal phase, but does not contain the YF3 crystal phase other than the orthorhombic crystal phase. The half-amplitude values ​​of the diffraction peaks of the (101), (020) and (210) planes of the orthorhombic YF3 crystal phase, the average crystallite size determined by the Williamson-Hall method are greater than 5 nm and less than 40 nm, and the Vickers hardness is greater than 400.

2. The yttrium fluoride spray coating according to claim 1, characterized in that, The yttrium oxyfluoride is selected from one or more of Y5O4F7, Y6O5F8 and Y7O6F9.

3. A yttrium fluoride-based spray coating, characterized in that, It includes the orthorhombic YF3 crystal phase, and does not include YF3 crystal phases other than the orthorhombic crystal phase. The half-amplitude values ​​of the diffraction peaks of the (101), (020) and (210) planes of the orthorhombic YF3 crystal phase, the average crystallite size determined by the Williamson-Hall method are greater than 5 nm and less than 40 nm, the Vickers hardness is greater than 400, and it also includes the Y5O4F7 crystal phase.

4. The yttrium fluoride spray coating according to claim 1 or 3, characterized in that, It does not contain the Y2O3 crystal phase.

5. The yttrium fluoride spray coating according to claim 1 or 3, characterized in that, The film thickness is 10–500 μm.

6. A spray coating film, which is a yttrium fluoride spray coating film as described in claim 1 or 3 formed on a substrate, characterized in that, The sprayed coating with a specified surface area is immersed together with the substrate in ultrapure water, and ultrasonically cleaned for 30 minutes with an output power of 200W. The sprayed coating and the substrate are then removed from the cleaning solution and dried. Next, the sprayed coating and the substrate are immersed together in ultrapure water and subjected to ultrasonic treatment at an output power of 200W for 15 minutes. Then, the sprayed coating and the substrate are removed from the treatment solution together. Next, 2 ml of 5.3N nitric acid aqueous solution is added to every 20 ml of the treatment solution to dissolve the yttrium particles in the treatment solution that have detached from the sprayed coating. Secondly, when quantifying the yttrium content in the treatment solution using ICP-based luminescence spectrophotometry, the value equivalent to the yttrium mass per unit surface area of ​​the yttrium-based particles is 1 μg / cm³. 2 the following.

7. A spray-painted component, characterized in that, It includes a substrate and a fluorinated yttrium-based spray coating formed on the substrate according to any one of claims 1 to 6.

8. The spray-painted component according to claim 7, characterized in that, The yttrium fluoride spray coating is a single-layer structure coating.

9. The spray-coated component according to claim 7 or 8, characterized in that, For use in semiconductor manufacturing equipment.

10. A method for manufacturing a yttrium fluoride-based spray coating film, comprising the method for manufacturing the yttrium fluoride-based spray coating film as described in claim 1 or 3, and specifically a method for manufacturing a yttrium fluoride-based spray coating film comprising an orthorhombic YF3 crystal phase and an oxy-yttrium fluoride crystal phase, and excluding a YF3 crystal phase other than the orthorhombic crystal system, characterized in that... The process includes the following steps: plasma spraying of powder containing orthorhombic YF3 crystal phase and powder containing YF3 crystal phase other than orthorhombic. The coating powder is either a granulated / unsintered powder or a granulated / sintered powder containing only the orthorhombic YF3 crystal phase and the yttrium oxyfluoride crystal phase; or a granulated / unsintered powder containing only the orthorhombic YF3 crystal phase and the Y2O3 crystal phase.

11. The manufacturing method according to claim 10, characterized in that, The plasma spraying is atmospheric plasma spraying.

12. The manufacturing method according to claim 11, characterized in that, The spraying distance in the atmospheric plasma spraying process is 50-90mm.

13. The manufacturing method according to claim 10, characterized in that, In the plasma spraying process, a mixture of argon and hydrogen is used as the plasma gas.

14. The manufacturing method according to claim 13, characterized in that, The argon gas supply rate is above 40 NLPM.

15. The manufacturing method according to claim 13, characterized in that, The hydrogen supply rate is above 8 NLPM.

16. The manufacturing method according to claim 10, characterized in that, The oxygen content of the spray powder is less than 7% by mass.

17. The manufacturing method according to claim 10, characterized in that, The yttrium oxyfluoride crystal phase contained in the spray powder is selected from one or more of Y5O4F7, Y6O5F8 and Y7O6F9.

18. The manufacturing method according to any one of claims 10 to 17, characterized in that, It does not include the following process: heat treatment of the yttrium fluoride coating formed by plasma spraying.

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