JP2015042786A - Method for forming thermal spray film of fluoride, and member coated with thermal spray film of fluoride - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a member coated with a thermal spray film of a fluoride formed by adhering a thermal spray film of a fluoride having excellent characteristics (corrosion resistance, plasma etching resistance) in quality by suppressing thermal decomposition reaction and oxydation reaction, and to provide a method for forming a film by firmly adhering the film.SOLUTION: There are provided a method for forming a thermal spray film of a fluoride, and a thus formed member coated with the thermal spray film of a fluoride. In the method for forming a thermal spray film of a fluoride, particles of a thermal spray fluoride material are sprayed to a substrate surface at a flying particle speed of 500 m/sec or higher by using an inert gas of a temperature of 600-1300°C as a functional gas for coating. The particles are thus adhered to the substrate so as to form an implantation structure where at least part of the particles of a thermal spray fluoride material cuts into concaves of the preheated, rough surface of the substrate.

Description

  The present invention relates to a method for forming a fluoride sprayed coating and a member coated with a fluoride sprayed coating, and in particular, on the surface of a member for a semiconductor processing apparatus that is subjected to plasma etching in an environment where various halogen gases and halogens are present. A method of forming a fluoride spray coating excellent in corrosion resistance and plasma etching resistance and a fluoride spray coating coated member obtained by carrying out this method are proposed.

  Equipments such as dry etchers, CVD, and PVD used in semiconductor processing and liquid crystal manufacturing processes need to improve the precision of microfabrication associated with the high integration of circuits formed on substrates such as silicon and glass. As for the processing environment, higher cleanliness is required. On the other hand, in various processes for microfabrication, highly corrosive gas or aqueous solution such as fluoride and chloride is used. As a result, secondary environmental pollution caused by corrosion products cannot be ignored.

Semiconductor device manufacturing / processing steps belong to a so-called dry process in which a compound semiconductor composed mainly of Si, Ga, As, P, or the like is used and processed in a vacuum or a reduced pressure environment. In this dry process, various types of film formation, impurity implantation, etching, ashing, cleaning, and the like are repeatedly performed in the environment. Equipment and members used in such dry processes include oxidation furnaces, CVD equipment, PVD equipment, epitaxial growth equipment, ion implantation equipment, diffusion furnaces, reactive ion etching equipment, and piping attached to these equipment, There are components and parts such as exhaust fans, vacuum pumps, and valves. Moreover, these devices include fluorides such as BF ₃ , PF ₃ , PF ₆ , NF ₃ , WF ₃ , HF, BCl ₃ , PCl ₃ , PCl ₅ , POCl ₃ , AsCl ₃ , SnCl ₄ , TiCl ₄ , It is known to use highly corrosive agents and gases such as chlorides such as SiH ₂ Cl ₂ , SiCl ₄ , HCl and Cl ₂ , bromides such as HBr, NH ₃ and CH ₃ F.

In the dry process using a halide, plasma (low temperature plasma) is often used to activate the reaction and improve processing accuracy. In the plasma usage environment, various halides form highly corrosive atomic or ionized F, Cl, Br, and I, and exert a great effect on fine processing of semiconductor materials. Particles such as fine SiO ₂ , Si ₃ N ₄ , Si, and W that have been scraped off by the etching process float in the processing environment from the surface of the semiconductor material (particularly plasma etching process), and these are being processed Alternatively, there is a problem that the quality of the device is significantly reduced by adhering to the surface of the processed device.

As one of countermeasures against these problems, there is conventionally a method of treating the surface of a semiconductor manufacturing / processing apparatus member with aluminum anodic oxide (alumite). In addition, oxides such as Al ₂ O ₃ , Al ₂ O ₃ .Ti ₂ O ₃ , Y ₂ O ₃ , oxides of Group IIIa metal of the periodic table are sprayed or vapor-deposited (CVD method, PVD method) For example, there is a technique of coating the surface of the member by using the above, or using these as a sintered body (Patent Documents 1 to 5).

More recently, plasma erosion resistance has been improved by irradiating the surface of Y ₂ O ₃ , Y ₂ O ₃ -A1 ₂ O ₃ sprayed coating with a laser beam or electron beam to remelt the surface of the sprayed coating. The technique to make it appear also (patent documents 6-9).

There is also a proposal of using a fluoride coating of a metal element belonging to a halogen compound as a corrosion-resistant coating for a member for a semiconductor processing apparatus. For example, Patent Document 10 discloses a method in which a surface of a ceramic sintered body such as silicon nitride or silicon carbide is coated with a rare earth element or alkaline earth element fluoride by a magnetron sputtering method, a CVD method, a thermal spraying method, or the like. ing. Further, Patent Document 11 has a proposal for a member in which a YF ₃ film is formed on an A1 ₂ O ₃ base material.

  Patent Document 12 discloses a method for producing a susceptor using a powder mainly composed of a fluoride of Y and a lanthanoid element, and Patent Documents 13 and 14 include fluoride particles of Group IIIa elements in the periodic table. A technique is disclosed in which a film is formed by a thermal spray heat source such as an inert gas plasma or a combustion gas flame, and then heat treatment at 200 ° C. to 250 ° C. is performed to change the crystal into stable orthorhombic crystals.

  Further, Patent Document 15 proposes a spraying particle for rare earth-containing mixture (oxide, fluoride, chloride) containing Y of particles granulated from primary particles having an average particle diameter of 0.05 μm to 10 μm. Patent Document 16 discloses a technique that uses a cold spray method or an aerosol deposition method in addition to a plasma spray method at a high heat source temperature as a method for forming a fluoride spray coating.

JP-A-6-36583 Japanese Patent Laid-Open No. 9-69554 JP 2001-164354 A Japanese Patent Laid-Open No. 11-80925 JP 2007-107100 A Japanese Patent Laid-Open No. 2005-256093 JP 2005-256098 A JP 2006-118053 A JP 2007-217779 A Japanese Patent Laid-Open No. 11-80925 JP 2002-001865 A JP 2001-351966 A JP 2004-197181 A Japanese Patent Laid-Open No. 2005-243988 JP 2002-302754 A JP 2007-115973 A JP 2007-308794 A

  In the present invention, among the above-described conventional techniques, the following problems relating to the fluoride spray coating formed by the spraying method and the coating forming method thereof are improved, and the halogen corrosion resistance and plasma erosion resistance are improved. The aim is to propose an excellent fluoride spray-coated member and a method for forming the same.

(1) The following phenomenon occurs when a film is formed by a thermal spraying method using a combustion flame such as inert gas (Ar, He) plasma, hydrocarbon gas, or kerosene as disclosed in Patent Document 12. That is, in the thermal spraying method using plasma as a heat source, fluoride particles flying in a high temperature jet flame are exposed to a high temperature environment of 5000 ° C. to 7000 ° C., and even a combustion flame is 2000 ° C. to 2800 ° C. Since a high temperature atmosphere is configured, in any heat source, some of the fluoride particles induce a thermal decomposition reaction and an oxidation reaction, and F ₂ gas is released.

Then, with the release of the F ₂ gas, the components of the fluoride particles are changed, and the formed fluoride film is stoichiometrically changed. For example, when plasma spraying is performed using YF ₃ particles, it is presumed that F ₂ gas is released in the heat source and changes to a fluoride represented by YF _3-X .

However, it is presumed that the halogen resistance of the yttrium fluoride sprayed coating represented by YF _3-X is chemically unstable as compared with the film forming fluoride particles (YF ₃ ). This is about the yttrium fluoride film in paragraph (0010) of Patent Document 13. “It was found that the color of the yttrium fluoride film is changed by corrosive halogen gas only by using yttrium fluoride. It can be seen from the description that “it was found that corrosion resistance is not sufficient by using yttrium fluoride alone and the yttrium fluoride film is depleted.”

(2) Further, in the technique disclosed in Patent Document 13, as a measure for changing the color of the coating and reducing corrosion resistance, the amorphous fluoride sprayed coating immediately after film formation is subjected to heat treatment at 200 ° C. to 500 ° C. A technology to change to orthorhombic is proposed. However, even if this method is applied, as described in paragraph (0014) of this document 13, the change in the color of the film is reduced, and this is not a drastic measure.

(3) Furthermore, as for the method of forming a fluoride film described in Patent Document 16, the paragraph (0021) describes that a cold spray method, an aerosol deposition method, or the like is desirable. On the other hand, when it is applied as a thermal spraying method, it is stated that “if a hydrogen gas is further mixed with a plasma gas such as argon or helium, the plasma temperature becomes high and a denser film can be formed”. However, the cold spray method is according to the Journal of the Japan Thermal Spray Association, “Spraying Technology Vol. 26 No. 2/3, published on January 31, 2007, pages 18 to 25, overview of cold spray and trends in research and development” , Ar, N ₂ , He, or other inert gas is heated to 500 ° C., and film-forming particles are sprayed at a high speed of 300 to 1200 m / S.

  In this method, there is an explanation that the gas at 500 ° C. is lowered to room temperature due to the adiabatic expansion phenomenon in the sprayed portion of the nozzle. Under these conditions, it cannot be said that the method is suitable for forming a fluoride film.

Further, Patent Document 16 does not explain the detailed contents of the cold spray method necessary for forming the fluoride film. That is, in order to further increase the plasma heat source temperature of the plasma spraying method, which is significantly higher than that of the cold spray method, the film is formed by increasing the plasma temperature by mixing H ₂ gas into an inert gas such as Ar or He. Although the method of forming a fluoride film is recommended, on the other hand, although there is a technical contradiction such as the ability to form a film at a low gas temperature by the cold spray method, the reason is completely mentioned. Not done.

(4) Moreover, in the method of heat-treating the fluoride sprayed coating as in Patent Documents 13 and 16, in addition to the increase in the manufacturing process, there is a problem that the production efficiency is reduced and the cost is increased. However, there was a problem that the corrosion resistance of the film could not be sufficiently recovered.

(5) Further, in the process of forming a fluoride sprayed coating by the atmospheric plasma spraying method or the high-speed flame spraying method, the fluoride particles for film formation are thermally decomposed in a high-temperature heat source, and harmful F ₂ gas with a strange odor is generated. , The work environment is deteriorated and there is a problem in work safety and health.

(6) Furthermore, although the fluoride sprayed coating has excellent halogen resistance, it has a drawback of poor adhesion to the substrate. However, there are few prior art documents describing this cause and countermeasures. Moreover, even if it is disclosed, it is only an application of a general blast treatment, and the intention to improve the adhesion of the fluoride spray coating is not recognized.

For example, Patent Document 13 and Patent Document 16 only disclose that the surface of the substrate is roughened with steel balls or corundum (Al ₂ O ₃ ), and Patent Document 17 discloses roughening with Al ₂ O ₃ . In addition, there is no description about the blast roughening treatment and the undercoat material as measures for improving the adhesion of the film, and the surface roughness is not disclosed.

(7) Moreover, each of the above-mentioned patent documents employs a method in which a fluoride sprayed coating is directly formed on the surface of a substrate, and conditions for blasting as a pretreatment for forming a fluoride sprayed coating Since there is no description about the necessity of undercoat construction, it is clear that the adhesion of the fluoride sprayed coating is not considered important, and despite this, the coating often peels off. However, no investigation was made on the solution.

  Accordingly, an object of the present invention is to provide a fluoride sprayed coating coated member in which a fluoride sprayed coating having good quality characteristics (corrosion resistance, plasma etching resistance) is adhered by suppressing thermal decomposition reaction and oxidation reaction. And providing a method for forming the coating on the surface of the substrate.

  The present invention is a conventional fluoride spray coating forming method formed by a thermal spraying method with a high heat source temperature as a result of earnest research to overcome the above-mentioned problems of the prior art and reliably realize the above object. Then, there was a problem that not only the chemical and physical properties of the film deteriorated, but also the adhesion was bad. To solve this problem, a new method of forming a thermal sprayed film from the following viewpoint The present invention was conceived based on the knowledge that the adoption of this is advantageous.

(1) About the spraying of fluoride, the temperature of the spraying heat source is about 600 ° C. to 1300 ° C., and an inert gas such as Ar, N ₂ , or He is used alone or in a mixed state. It is advantageous to use it as a fluid drive source.
(2) It is preferable to spray the fluoride spray material at a high speed of 500 m / second or more. Since such high-speed spraying collides with the surface of the sprayed particles with a large kinetic energy, at least a part of the sprayed particles adheres to the concave portion of the adherend surface, that is, a flocked structure. As a result, the coating-formed fluoride sprayed coating can be firmly fixed by forming a flocked state through the roughened concave portion of the substrate. That is, this can improve the adhesion of the fluoride spray coating.
(3) substrate for coating a fluoride spray coating, in compliance with the ceramic sprayed coating work standard pre JIS H9302 defining its surface, with degreasing or descaling, abrasives such as _A1 2 _{O 3} and SiC It is preferable to form irregularities by blast roughening using particles, or to preheat.
(4) It is preferable to form a film by keeping the distance between the nozzle of the spray gun using an inert gas as a driving source and the surface of the substrate at 5 to 50 mm and coating with a fluoride sprayed film having excellent adhesion. .

The present invention, developed from the viewpoint described above, forms a fluoride sprayed material on the surface of the substrate that has been roughened and preheated, and an inert gas composed of Ar, N ₂ , He, or a mixed gas thereof. Using a spray gun as a working gas for the film, in a spraying atmosphere of 600 ° C. to 1300 ° C., the flight speed: 500 m / sec. By spraying at the above speed, a fluoride sprayed coating is formed such that at least a part of the fluoride sprayed particles has a flocking structure in which the roughened / preheated surface of the base material is bitten into the recesses. Is a method for forming a fluoride sprayed coating characterized by forming a coating.

  Further, the present invention comprises a base material, and a fluoride sprayed coating that is coated directly on the roughened / preheated surface of the base material that has been subjected to a roughening treatment and a preheat treatment, and The portion where the fluoride sprayed coating is in contact with the roughened / preheated surface of the substrate is a spray speed of 500 m / sec. It is sprayed at the above high speed, and has a flocking structure in which at least a part of the tip of the fluoride spray particles is attached so as to bite into the concave portion of the roughened / preheated surface of the substrate. We propose a featured fluoride spray coating coated member.

In the present invention,
(1) In addition to roughening and preheating treatment, pre-treatment of degreasing and descaling,
(2) The base material is any of Al and alloys thereof, Ti and alloys thereof, steel containing carbon, various stainless steels, Ni and alloys thereof, oxides, nitrides, carbides, silicides, and carbon sintered bodies. Using
(3) The fluoride spray coating is composed of Mg in the periodic table group IIa, Al in the periodic table group IIIb, Group IIIa in the periodic table Y, lanthanum (La), a lanthanoid metal having atomic numbers 57 to 71, and cerium. (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), eurobium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), one or more kinds of fluoride particles selected from fluorides of lutetium (Lu) are sprayed to form a film thickness of 20 μm to 500 μm. The film is formed,
(4) The surface roughening treatment of the base material is performed by spraying a grinding material such as Al ₂ O ₃ or SiC, whereby the surface roughness is Ra: 0.05 to 0.74 μm, Rz: 0.09 to 2. To 0 μm,
(5) In the spraying method using the inert gas as a working gas for film formation, the distance between the tip of the injection nozzle and the substrate surface when the fluoride particles are injected is maintained at an interval of 5 to 50 mm.
(6) The flying speed of the fluoride spray particles is 500 m / sec. 1000 m / sec. To the following speed,
(7) The flying speed of the fluoride spray particles is 650 m / sec. 1800 m / sec. To the following speed,
(8) The temperature of the working gas and the spraying atmosphere should be 600 ° C. or more and 1300 or less,
However, this is a more preferable solution.

According to the present invention having the above-described configuration, the following effects can be expected.
(1) Since the spray heat source for heating the fluoride spray particles for film formation uses an inert gas such as Ar, N ₂ , and He, the fluoride particles flying in the spray heat source are oxidized, It reaches the adherend surface without alteration and becomes a sprayed coating. Therefore, since the thermal spraying is performed in a non-oxidizing atmosphere, the oxidation reaction is suppressed, and the original performance of the fluoride is not impaired, and a stable quality is obtained.
(2) The thermal spray heat source temperature of the inert gas for heating the fluoride particles is as follows: heat source temperature of general plasma spraying method: 5000 ° C. to 7000 ° C., heat source temperature of high-speed flame spraying method: 1800 ° C. to 2800 ° C. Compared to the above, since the temperature is much lower, 600 ° C to 1300 ° C, a thermal spray coating that suppresses the thermal decomposition reaction of fluoride particles and does not cause chemical mass change and accompanying deterioration of physicochemical properties is formed. it can.
(3) Furthermore, since the velocity of the fluoride spray particles flying in the inert gas is set to 500 m or more per second, the temperature exposure time of the particles is short (1/1000 seconds), and the above (1), (2 ) And the impact energy to the substrate surface obtained by applying large kinetic energy to the fluoride particles, combined with the presence of the carbide cermet undercoat layer, The adhesion can be improved.
(4) By aligning the above-mentioned conditions such as low temperature, inert gas heat source, high speed flying particles, etc., high vapor pressure fluoride particles (for example, AlF) at high temperatures that could not be formed by the current plasma spraying method etc. ₃ ) and the like can be easily formed.
(5) In addition to the conditions of the thermal spraying method, the surface of the base material for depositing the thermal spray coating is roughened by blasting and the undercoat of carbide cermet is applied, and the base material is preheated to 80 ° C. to 700 ° C. Therefore, the adhesion force (adhesion force) of fluoride particles that collide with the substrate surface can be improved.
(6) In particular, the fluoride particles sprayed on the surface of the substrate that has been roughened (Ra: 0.05 to 0.74 μm, Rx: 0.09 to 2.0 μm) and preheated. Fluoride spraying with some improvements in the throwing effect by part of the projections and depressions (the work that improves the adhesion between the coating and the undercoat layer by mechanically engaging the particles with the rough surface (recesses) of the substrate) It is possible to improve the adhesion / deposition rate of the material particles and the adhesion.
(7) Since fluoride has a small surface energy, the mutual bonding force of fluoride particles constituting the film and the adhesiveness to the substrate are low, and there is a defect that the fluoride often peels off. In this regard, according to the present invention, since the surface of the base material is roughened, the physical adhesion of fluoride particles and the chemical affinity act synergistically to improve the adhesion of the film. .

It is the figure which showed the flow of the process for implementing this invention method. It is a figure which shows the particle | grain behavior state of the initial stage which sprayed the sprayed particle on the base-material surface by the high-speed flame spraying method. (A) is a surface sprayed with the sprayed particles, (b) is a cross section sprayed with sprayed particles, It is a basic diagram of the apparatus for low-temperature sprayed coating formation utilized with the method of this invention. It is a basic diagram of the other apparatus for low-temperature sprayed coating formation utilized by the method of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the flow of steps for carrying out the method of the present invention. Hereinafter, the present invention will be described in the order of the steps.
(1) Base Material The base material that can be used in the present invention includes Al and its alloys, Ti and its alloys, various alloy steels including stainless steel, carbon steel, Ni and their alloys, and the like. In addition, ceramic sintered bodies such as oxides, nitrides, carbides, silicides, and sintered carbon materials may be used.

(2) Pretreatment This treatment is preferably carried out in accordance with the ceramic spraying work standard defined in JIS H9302. For example, degreasing and descaling treatment to remove rust, oils and fats on the surface of the substrate, or after that, grinding particles such as Al ₂ O ₃ and SiC are sprayed to roughen the surface, and fluoride particles are likely to adhere. To. The surface roughness of the substrate after roughening is preferably about Ra: 0.05 to 0.74 μm and Rz: about 0.09 to 2.0 μm.

FIG. 2 is a reference photograph showing a cross-sectional form of the substrate surface and its portion immediately after spraying the sprayed particles onto the substrate surface by a high-speed flame spraying method at a flying speed of 550 m / sec.
FIG. 2 (a) shows that a part of sprayed WC-Co cermet sprayed particles adhere to the surface of the substrate so as to decrease, while the other WC-Co cermet particles impinge on the substrate. Thus, a part of the crushed material is dispersed and adhered and coated. Moreover, FIG.2 (b) observes the distribution condition of the WC-Co cermet particle sprayed on the base-material surface layer part in the cross-sectional state. As is apparent from this photograph, the WC-Co cermet particles are in a state in which small piles are sparsely stabbed on the surface of the base material, and other parts are simply attached or buried. The more the number of sprays, the more uniform it becomes.

(4) Preheating of base material etc. The base material after the roughening treatment is preheated prior to thermal spraying of fluoride particles. The preheating temperature is preferably controlled by the base material, and the following temperatures are recommended.
(I) Al, Ti and alloys thereof: 80 ° C to 250 ° C
(Ii) Steel (low alloy steel): 80 ° C to 250 ° C
(Iii) Stainless steel: 80 ° C to 250 ° C
(Iv) Ceramic sintered bodies such as oxides and carbides: 120 ° C to 500 ° C
(V) Sintered carbon: 200 ° C to 700 ° C

  The preheating may be performed in the air, in a vacuum, or in an inert gas, but it is necessary to avoid an atmosphere in which the base material is oxidized by preheating and an oxide film is formed on the surface.

In the method of the present invention, one of the biggest reasons for preheating the substrate is that when an inert gas is injected from the nozzle at a high speed, the gas temperature of, for example, about 600 ° C. reaches about 50 ° C. due to the adiabatic expansion phenomenon of the gas. This is because there is a risk that the temperature of the base material is lowered and the substrate is thereby cooled. If the surface temperature of the substrate becomes such a low temperature, fluoride particles injected from the nozzle (the melting point of fluoride is YF ₃ (1152 ° C.), ErF ₃ (1350 ° C.)) If it collides with the substrate surface as it is without melting in the gas, most of the material will scatter and the probability of film formation will be very low. This is because the quality is deteriorated such that the film is weak and has a high porosity.

  The present invention improves the adhesion of fluoride particles by roughening the surface of the substrate, preheating the substrate, and applying large kinetic energy by hot high-speed spraying of the fluoride particles with an inert gas described later. It is intended.

(5) Formation of fluoride spray coating (top coat) a. Fluoride spray material The fluoride spray material used in the present invention includes elemental periodic group IIa group Mg, periodic table group IIIb group Al, periodic table group IIIa group Y, and lanthanoids belonging to atomic numbers 57-71. It is a fluoride of a metallic metal. The metal element names of atomic numbers 57 to 71 are lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd). , Terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

  And as a thermal spray material, what adjusted the particle size of the said metal fluoride particle to 5-80 micrometers is used. That is, if the sprayed material is fine particles of 5 μm or less, there is a disadvantage that more particles are scattered when colliding with the surface of the substrate, and if the particles are larger than 80 μm, the feed rate to the spray gun is uniform. This is because, on the other hand, the tendency of the pores of the formed film to become large becomes remarkable.

  The sprayed coating with fluoride particles formed on the surface of the base material after pre-heating of the roughening treatment should have a thickness of 20 to 500 μm, and particularly preferably in the range of 50 to 200 μm. That is, when the film is thinner than 20 μm, a uniform film thickness cannot be obtained. When the film is thicker than 500 μm, the residual stress at the time of forming the fluoride film increases, resulting in a decrease in adhesion to the base material and peeling. It is easy to do.

(B) Thermal spraying apparatus and film-forming method As an apparatus used in carrying out the present invention, the low-temperature thermal spray coating member described in Patent No. 4628578 previously proposed by the inventors and the apparatus used in the manufacturing method thereof are used. Can be used. FIG. 3 and FIG. 4 show a preferred example of an apparatus effective in forming the fluoride sprayed coating according to the present invention on the surface of the substrate in such an apparatus. In the figure, l is a working gas source supplied from a compressed gas cylinder, 2 is a spraying material supplier, 3 is a gas pressure heat exchanger, 4 is a spraying container, 5 is a spray gun, 6 is a nozzle, and 7 is a workpiece. , 8 is a silencer, 9 is a main gas pipe for working gas, 10 is a sub-gas pipe for conveying the sprayed material powder, 11 is a rectifying plate for working gas, and 12 and 13 are flow control valves provided in the respective gas pipes. It is.

  These illustrated apparatuses divide the high-pressure inert gas supplied from the working gas source 1 into two, send one of the gases as the working gas to the heat exchanger 3 and heat it to 600 to 1300 ° C. The jet gas is jetted from the nozzle 6 toward the workpiece 7 as a sonic flow jet gas. The lower limit is preferably 700 ° C. or higher, more preferably 800 ° C., and the upper limit is preferably 1000 ° C. At this time, temperature control is performed so as to prevent an extremely low temperature accompanying adiabatic expansion.

  If the temperature of the working gas is less than the lower limit (600 ° C.), the temperature is lowered to about 50 ° C. due to the adiabatic expansion phenomenon at the outlet of the injection gun, and the temperature increase effect of the fluoride particles cannot be obtained. On the other hand, when the temperature exceeds the upper limit (1300 ° C.), the energy required for heating the inert gas increases and the heat treatment cost for the accessory device increases.

  The other branched gas is used as a gas for conveying the spray powder material, but is merged with the working gas in the spray gun 5 to form a supersonic gas flow in the nozzle 6 (in the case of FIG. 3). The sprayed material particles are caused to fly and collide toward the object to be processed at a high speed, and sprayed so that at least a part of the sprayed material bites into the adherend surface and gradually thickened to form a sprayed coating having a predetermined thickness. Further, as shown in FIG. 4, the sprayed material particles may be introduced from the pressure reducing portion at the outlet of the spray gun 5 (near the attachment portion of the nozzle 6). In any case, the distance between the nozzle 6 and the object to be processed is 5 to 50 mm, preferably 10 to 30 mm. If the distance is smaller than 5 mm, the gas flow is obstructed, and if the distance is larger than 50 mm, the adhesion rate of fluoride particles. Is significantly reduced.

  Using an inert gas from the nozzle 6 of the thermal spray gun 5 as a working gas for film formation, fluoride spray material particles are added at 500 m / sec. The object 7 is sprayed at the above flight speed. The flight speed at this time is 500 m / sec. The reason for the above is 500 m / sec. It is because the adhesion rate of the fluoride particle with respect to the base material surface will fall extremely if less than. The preferred lower limit flight speed is 500 m / sec. , More preferably 650 m / sec. It is. On the other hand, the upper limit of the flight speed is related to the performance of the thermal spraying apparatus, but is 800 m / sec. Or less, more preferably 750 m / sec. It is preferable to make it about.

  The supersonic gas generating part (nozzle 6) and the object 7 are protected by the steel spraying container 4, and the shock wave sound generated by the supersonic gas is combined with the action of the silencer 8. The structure is such that it does not leak to the outside.

The characteristic feature of the present invention is that an inert gas such as Ar, N ₂ or He alone or a mixed gas thereof is used as the high-pressure working gas to be used. Moreover, it is suitable to control the pressure of these gases within the range of 0.5 to less than 1.0 MPa. In the present invention, the reason why attention is given to the inert gas as an example as the working gas is that, even if heated to a high temperature of 1300 ° C., various metal members constituting the thermal spraying apparatus are not oxidized and consumed. This is because the physicochemical change due to the oxidation reaction of the particles can be minimized even when the chemical particles are heated. And the reason which makes the pressure less than 0.5-1.0 MPa is because it is suitable for utilizing the kinetic energy of the inert gas for heat sources. The use of a pressure gas of 1 MPa or more is not problematic in film formation, but requires legal measures in handling high-pressure gas and is not preferable from the viewpoint of work safety.

(C) Features of Fluoride Sprayed Coating As the physicochemical properties of fluoride itself, the following points can be pointed out. That is, although the fluoride film has chemical stability against halogen-based gas as compared with a metal film or ceramic film, the surface energy is small, so the mutual bonding force of the fluoride particles constituting the film and the substrate The adhesion strength is weak. Further, since a large residual stress is likely to be generated during film formation, peeling of the film often occurs easily due to slight deformation of the base material after film formation. In addition, since fluoride exhibits poor ductility, the film easily “cracks” and causes corrosion of the base material due to internal penetration of acid or alkaline cleaning liquid together with pores generated during film formation. Even if the corrosion resistance of the fluoride itself is good, there is also a problem that the property cannot be used as a corrosion protection film.

  In this regard, according to the present invention, the strength of the thermal spray coating itself improves the mutual bonding force between the particles, improves the adhesion of the coating, and can solve the above-mentioned problems of the fluoride. . That is, the effect of preventing the peeling of the film and cracking and preventing the corrosion of the base material by preventing the intrusion of the cleaning liquid associated therewith occurs.

  The fluoride spray coating formed in conformity with the present invention can be used as it is, but if necessary, heat treatment at 250 ° C. to 500 ° C. is performed after film formation to release the residual stress. It is also easy to crystallize an amorphous material (orthorhombic system). Therefore, in the present invention, the implementation of these processes is not particularly limited. The reason for limiting the temperature of this heat treatment to the above-mentioned range is that if it is 250 ° C. or lower, it takes a long time to release the residual stress of the coating, and crystallization is insufficient, and if it is 500 ° C. or higher, the fluoride sprayed coating This is because it may promote changes in physicochemical properties.

Example 1
In this example, YF ₃ and AlF ₃ were used as fluorides, and the temperature of the working gas for film formation and the feasibility of forming a fluoride spray coating were investigated.
(1) Base material: SUS304 steel (dimensions: 30 mm × 30 mm × thickness 5 mm) is used as a base material, and after blast roughening the surface, WC-12Co (numbers indicate mass%) by high-speed flame spraying. The same applies to the following examples), and the spraying flight speed is 630 m / sec. The undercoat layer was applied to a thickness of 100 μm by spraying under the condition of 8 spraying times, and then preheated to 180 ° C. was used.
(2) Spraying atmosphere: An inert residue consisting of Ar, N ₂ and He is used as a film forming working gas, and each gas temperature is heated from less than 500 ° C. to a maximum of 1300 ° C., and flies in the molten steel atmosphere. While maintaining the flight speed of the fluoride particles at 600 to 660 m / S, the presence or absence of a fluoride film formed on the surface of the substrate was examined.
(3) Fluoride material for film formation: YF ₃ and AlF ₃ having a particle size of 10 to 35 μm were used as fluorides. In addition, as the thermal spraying method of the comparative example, the current atmospheric plasma spraying method using Ar and hydrogen gas as plasma working gas and the low pressure plasma spraying method (particle flight speed: 350 to 500 m / S) are used, and each plasma jet is used as a heat source. YF ₃ and AlF ₃ were deposited.

(4) Test results Table 1 shows the test results. As is apparent from the results shown in this table, in the thermal spraying method according to the present invention, when the film forming working gas (Ar, N ₂ , He) is less than 500 ° C., no fluoride film is formed (fluoride particles). Even in the case where adhesion was observed, it was confirmed that the formation of a favorable film was observed in appearance with a porous and impractical state) and a gas temperature of 600 ° C. or higher.
On the other hand, in the current atmospheric plasma spraying method and low pressure plasma spraying method, YF ₃ film formation is observed, but the AlF ₃ film has many defects (poor and inferior in uniformity) and is practical. No film properties were obtained. This is presumably because AlF ₃ has a very high vapor pressure, and thus vaporized or decomposed from the surface of AlF ₃ particles when flying in a high-temperature plasma jet.

(Example 2)
In this example, the influence of the film formation method and the pretreatment on the base material on the porosity of the fluoride spray coating formed on the surface of SS400 steel was investigated.
(1) Base material: As a base material, SS400 steel (dimensions: width 50 mm × length 50 mm × thickness 3.2 mm) was used, and a material subjected only to a blast roughening treatment with current alumina particles was prepared.
(2) Spraying atmosphere: Ar gas heated to 750 ° C. was used as the working gas for film formation, and the flight speed of YF ₃ particles flying in this spraying atmosphere was 650 to 700 m / sec. Controlled to range.
(3) Fluoride for film formation: YF ₃ (particle size: 10 to 40 μm) is used, and as the film of the method of the present invention and the comparative example, the same current atmospheric plasma spraying method and high-speed flame spraying method as in Example 1 are used. A thickness of 120 μm was formed.
(4) Feroxyl test (porosity)
Specifically, the following method was used as a ferroxyl test method. That is, 10 g of potassium hexacyanoferrate (III) and 15 g of sodium chloride are dissolved in 1 liter of distilled water, and the filter paper for analysis is sufficiently impregnated. Thereafter, the filter paper was affixed to the surface of the test piece and allowed to stand for 30 minutes, and then the filter paper was peeled off to visually determine the presence or absence of blue spots on the filter paper surface. This is because the ferroxyl test solution penetrates into the amorphous membrane when penetrating pores are present, reaches the iron substrate interface and generates iron ions, and this reacts with potassium hexacyano (III) and reacts with blue on the surface of the filter paper. It can be determined by generating spots.

(5) Test results The test results are shown in Table 2. As is apparent from the results shown in this table, it was found that blue spots were generated from all the fluoride spray coatings tested, and through pores were present in the coating. However, when looking at the number of blue spots, 3-7 large blue spots are seen in the coatings (No. 2, 3) formed by the atmospheric plasma spraying method and the high-speed flame spraying method of the comparative example. The film (No. 1) formed by thermal spraying according to the method of the present invention has a small number of spots and shows a tendency toward densification as compared with the former. It was also found that the coating formed on the surface of the base material sprayed with WC-Co particles has few through pores and can be put to practical use as a pretreatment for forming a fluoride coating.

(Reference Example 1)
In this example, the flying speed of the fluoride particles and the preheating temperature of the base material are respectively changed to obtain the flying speed and the preheating temperature necessary for forming the fluoride film.
(1) Substrate: The same stainless steel as in Example 1 was used, and after blast roughening, an undercoat layer of WC-8Co-5Cr was applied to a thickness of 120 μm, and then in the range of 20 ° C. to 520 ° C. A preheated specimen was prepared.
(2) Spraying atmosphere: Ar gas heated to 750 ° C. is used as a working gas for film formation, and the speed of fluoride particles flying in this spraying atmosphere is less than 500 m / S, 600 to 700 m / S, and 750 m / S. Film formation was performed under three conditions.
(3) Fluoride for film formation: YF ₃ (particle diameter: 10 to 35 μm)

(4) Test results Table 3 shows the test results. As is clear from the results shown in this table, when the flight speed of YF ₃ particles was less than 500 m / S, sufficient film formation could not be obtained even when the preheating temperature of the substrate was changed from 20 ° C. to 520 ° C. (No .1). However, when the flying speed of the fluorine spray particles is set to 600 ° C. or higher, a film is formed when the preheating temperature of the substrate is maintained at 80 ° C. or higher. Even with the above, there was almost no change, and the formation of a good thermal spray coating was observed. Therefore, the flying speed of the fluorinated spray particles necessary for forming the fluoride film is 600 m / sec. As described above, it has been found that if the preheating temperature of the base material (SUS304 steel) is 80 ° C. to 500 ° C., a predetermined effect can be obtained.

  The maximum preheating temperature of the base material varies depending on the base material quality, and non-ferrous metals such as Al and Ti undergo deformation and metallurgical changes as the temperature rises, and steel materials generate oxide scale on the surface. Since a change occurs, it is preferable to suppress to a low temperature. In this respect, sintered bodies such as carbides and oxides are less affected by the heating temperature, so that a better thermal sprayed film is formed when the production temperature is as high as possible. .

Example 3
In this example, the formation speed of the fluoride particles and the formation state of the film with respect to the roughened state of the substrate surface were investigated.
(1) Substrate: The same SUS304 steel test piece as in Example 1 was used, and the surface was subjected to a blast roughening treatment or not. All the substrates were preheated to 200 ° C.
(2) Thermal spraying atmosphere: Ar gas heated to 700 ° C. is used as the working gas for film formation, and the flying speed of fluoride particles flying in this is less than 500 to 750 m / sec. It was adjusted to become.
(3) Fluoride for film formation: YF ₃ (particle size: 5 to 30 μm)

(4) Test results Table 4 shows the test results. As is apparent from the results shown in this table, the flying speed of the fluoride particles is 500 m / sec. Below, the formation of the fluoride film was not sufficient, and even if formed, it was porous and non-uniform. The particle velocity is 600 m / sec. As a result, a good film was formed on the blast roughened surface (No. 2).

(Reference Example 2)
In this reference example, a fluoride sprayed coating is formed on the surface of an Al alloy substrate (size: width 30 mm × length 50 mm × thickness 3 mm) by a method suitable for the present invention, and the plasma etching resistance of the coating is formed. Is evaluated.
(1) Substrate: After blasting roughening the surface of the (A3003 of JIS H4000 defined) Al _alloy, and applying a Cr ₃ C 2 -18Ni-8Cr to a thickness of 150 [mu] m, preheated to then 200 ° C..
(2) Spraying atmosphere: He gas heated to 800 ° C. was used as the film forming working gas, and the flying speed of the fluoride particles flying in this spraying atmosphere was controlled in the range of 650 to 700 m / S.
(3) Fluoride for film formation: YF ₃ , DyF ₃ , CeF ₃ (particle diameter 5 to 45 μm) was used to form a film with a film thickness of 180 μm. In addition, as a film of the comparative example, a film in which Y ₂ O ₃ , Dy ₂ O ₃ , and CeO ₂ were formed to 180 μm by the atmospheric plasma spraying method was evaluated under the same conditions.
(4) Plasma etching atmosphere gas composition and plasma output (i) Atmosphere gas and flow rate conditions (a) F-containing gas: CHF ₃ / O ₂ / Ar = 80/100/160 (flow rate cm ³ per minute)
(B) CH-containing gas: C ₂ H ₂ / Ar = 80/100 (flow rate cm ³ per minute)
(Ii) Plasma irradiation output High frequency power: 1300W
Pressure: 4Pa
Temperature: 60 ° C
(Iii) Plasma etching test atmosphere (a) Conducted in an F-containing gas atmosphere (b) Implemented in a CH-containing gas atmosphere (C) Implemented in an atmosphere in which an F-containing gas atmosphere 1h and a CH-containing gas atmosphere 1h are alternately repeated

(5) Evaluation method In the evaluation of the plasma erosion resistance test, the plasma erosion resistance and the environmental pollution resistance were investigated by measuring the number of particles of the film component scattered from the test film by the etching treatment. The particles were measured by measuring the time required for the number of particles having a particle size of 0.2 μm or more attached to the surface of an 8-inch diameter silicon wafer disposed in the test container to reach 30 particles.

(6) Test results Table 5 shows the test results. As is clear from this result, the oxide film (No. 1, 3, 5) of the comparative example has the least amount of generation of particles in the CH-containing gas, and is slightly increased in the F-containing gas to reach the allowable value. There is a situation where becomes shorter. However, it has been found that the number of particles generated in an atmosphere in which F-containing gas and CH-containing gas are alternately repeated is further increased. This is considered to be because the oxide film on the surface of the oxide ceramic film is always in an unstable state and scattered due to the repetition of the oxidizing action of the fluorinated gas and the reducing action of the CH gas in the F-containing gas. In contrast, the fluoride film (No. 2, 4, 6) maintains a chemically stable state in the F-containing gas, the CH-containing gas, and the atmosphere in which these gases are alternately repeated, and generates particles. It is thought to have been suppressed. In addition, it is thought that the environmental pollution resistance is also improved in that many are smaller by about 1/5 to 1/10 than those of the fluoride film.

Example 4
In this example, the influence of the pretreatment of the substrate surface on the adhesion of the fluoride spray coating was investigated.
(1) Kind of pretreatment The following pretreatment was performed on one side of an Al3003 alloy (dimension: diameter 25 mm x thickness 5 mm) as a base material.
(i) After degreasing, lightly polish with a wire brush.
(ii) After degreasing, Ni-20Cr is formed into a 50 μm-thick film by atmospheric plasma spraying (metal undercoat: reference example)
(iii) After degreasing, WC-12Co is applied with a high-speed flame spraying method (speed: 680 m / sec., with an undercoat layer having a thickness of 80 μm by seven sprays (reference example).
(iv) After degreasing, a blast roughening treatment is performed using an Al ₂ O ₃ abrasive.

(2) Formation of fluoride sprayed coating He gas heated to 800 ° C. is used on the surface of the base material, and the flying speed of fluoride particles flying through the substrate is set to 680 to 750 m / sec. A fluoride sprayed coating having a film thickness of 160 μm was formed by YF ₃ particles controlled in the above range.

(3) Adhesion test method The adhesion of the thermal spray coating was measured by the adhesion strength test method defined in the JIS H8666 ceramic thermal spray coating test method.

(4) Test results The test results are shown in Table 6. As is clear from the results shown in this table, the fluoride sprayed coating (No. 1) formed on the lightly brushed surface after degreasing the substrate surface has a poor adhesion and is 0.5 to 1.2 MPa. The fluoride sprayed coating (No. 2) with the coating peeled off and the metal undercoat provided a slight improvement in adhesion, but the effect was small. On the other hand, the fluoride sprayed coating (No. 3) on which the WC-12Co undercoat layer shown as a reference example formed a high adhesion of 12 to 17 MPa. On the other hand, the adhesion of the fluoride sprayed coating (No. 4) formed on the roughened blasted surface, which is an example suitable for the present invention, is higher than that of the wire brushing surface. It is recognized also in the fluoride sprayed coating (No. 5) after construction. These are respectively No. 1, no. Compared with the case of 2, it tends to be higher, and the roughening treatment of the base material shows an effect of improving the adhesion of the film.

As described above, the fluoride coating of the present invention obtained by thermal spraying using an inert gas as a working fluid at a relatively low temperature to an ultra-high speed can be obtained by thermally decomposing fluoride particles for film formation or removing F _{Since the two-} component phenomenon does not occur, the formed fluoride film exhibits the original physicochemical properties of fluoride. The fluoride spray coating formed in this way has better adhesion, acid resistance, halogen gas resistance, plasma erosion resistance, etc., compared to coatings formed by conventional plasma spraying and high-speed flame spraying methods. It has excellent physicochemical properties, and it can be expected to be used in fields where more stringent and superior performance is required as a coating for general petrochemical / chemical plants as well as coatings for current semiconductor processing equipment members.

DESCRIPTION OF SYMBOLS 1 Working gas source 2 Spraying material supply device 3 Gas heating heat exchanger 4 Spraying vessel 5 Spray gun 6 Nozzle 7 Processed object 8 Silencer 9 Main gas pipe 10 Sub gas pipe 11 Working gas rectifying plates 12, 13 valve

Claims (10)

On the surface of the base material that has been roughened and preheated,
In a spraying atmosphere of 600 ° C. to 1300 ° C. using a spray gun in which an inert gas composed of Ar, N ₂ , He, or a mixed gas thereof is used as a film forming working gas as a fluoride spraying material, flight speed: 500 m / sec. By spraying at the above speed, a fluoride sprayed coating is formed such that at least a part of the fluoride sprayed particles has a flocking structure in which the roughened / preheated surface of the base material is bitten into the recesses. A method for forming a fluoride sprayed coating, characterized in that the coating is formed.   As the base material, any one of Al and its alloys, Ti and its alloys, carbon-containing steel, various stainless steels, Ni and its alloys, oxides, nitrides, carbides, silicides, and carbon sintered bodies should be used. The method for forming a fluoride sprayed coating according to claim 1.   The fluoride spray coating is composed of Mg of periodic table group IIa, Al of group IIIb of periodic table, Group IIIa group Y of periodic table, lanthanum (La), cerium (Ce) which is a lanthanoid metal of atomic number 57-71. , Praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), eurobium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er) One or more fluoride particles having a particle size of 5 μm to 80 μm selected from fluorides of thulium (Tm), ytterbium (Yb), and lutetium (Lu) were sprayed to form a film thickness of 20 μm to 500 μm. The method for forming a fluoride sprayed coating according to claim 1, wherein the method is a coating. The base material is roughened to a surface roughness of Ra: 0.05 to 0.74 μm and Rz: 0.09 to 2.0 μm by pretreatment by spraying an abrasive such as Al ₂ O ₃ or SiC. The method for forming a fluoride sprayed coating according to any one of claims 1 to 3.   The distance between the tip of the thermal spray nozzle and the substrate surface when spraying fluoride particles by a thermal spraying method using the inert gas as a working gas for film formation is set to an interval of 5 to 50 mm. The formation method of the fluoride sprayed coating of any one of 1-4.   A fluoride sprayed coating that is coated directly on the roughened / preheated surface of the substrate that has been roughened and preheated, and is based on the fluoride sprayed coating. The part in contact with the roughened / preheated surface of the material is sprayed with fluoride spray particles having a particle size of 5 to 80 μm in a spraying atmosphere of 600 to 1300 ° C. at a high flight speed of 500 m / sec or more. Fluoride spraying characterized by having a flocking structure in which at least a part of the tip of the fluoride spray particles is attached so as to bite into the concave portion of the roughened / preheated surface of the substrate Film covering member.   The fluoride sprayed coating-coated member according to claim 6, wherein the fluoride sprayed coating has a thickness of 20 to 500 μm.   The base material is any one of Al and its alloys, Ti and its alloys, carbon-containing steel, various stainless steels, Ni and its alloys, oxides, nitrides, carbides, silicides, and carbon sintered bodies. The fluoride sprayed coating-coated member according to claim 6.   The fluoride spray coating is composed of Mg of periodic table group IIa, Al of group IIIb of periodic table, Group IIIa group Y of periodic table, lanthanum (La), cerium (Ce) which is a lanthanoid metal of atomic number 57-71. , Praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), eurobium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er) One or more fluoride particles having a particle size of 5 μm to 80 μm selected from fluorides of thulium (Tm), ytterbium (Yb), and lutetium (Lu) were sprayed to form a film thickness of 20 μm to 500 μm. The fluoride sprayed coating-coated member according to claim 6 or 7, which is a coating.   9. The surface of the pretreated substrate is a rough surface having a roughness Ra: 0.05 to 0.74 [mu] m and Rz: 0.09 to 2.0 [mu] m. Fluoride spray coating coated member.