JP5651848B2 - Fluoride cermet composite coating member and method for producing the same - Google Patents

Description

The present invention relates to a fluoride cermet composite film-coated member washed with an acid, alkali, or pure water and a method for producing the same, and in particular, a nickel plating metal is filled in a through-hole portion of a non-conductive fluoride sprayed film. Proposes a fluoride cermet composite film-coated member for a semiconductor processing apparatus , which is excellent in halogen corrosion resistance and plasma erosion resistance, and a method for producing the same.

The thermal spraying method uses a gas plasma flame such as Ar or H ₂ or a hydrocarbon combustion flame to soften or melt particles of metal (hereinafter referred to as metal, including alloys), ceramics, cermet, etc. This is one of the surface treatment techniques for spraying onto the surface of the object to be treated (base material) and depositing them to form a film. In this technology, as long as it is a material that softens or melts by heat, not only glass and plastic, but also metals such as tungsten (melting point 3,387 ° C.) and tantalum (melting point 2,996 ° C.) having a high melting point, Al ₂ Oxide ceramics such as O ₃ (melting point: 2,015 ° C.) and MgO (melting point: 2,800 ° C.) can be formed, and there is an advantage that the degree of freedom in selecting the kind of coating material is very large. For this reason, the application using the characteristic of a thermal spray coating has expanded to many industrial fields.

  In addition, the quality of sprayed coatings and spray guns greatly affect the quality of the sprayed coating, and therefore, further improvements and developments are energetically performed along with improvements in quality and productivity. For example, in Patent Document 1, since the metal film particles sprayed in the atmosphere contain a large amount of oxides, air is used as a cause of a decrease in mutual bonding force between particles constituting the film and adhesion with a substrate. A method and apparatus for plasma spraying (reduced pressure plasma spraying) in an excluded low pressure argon gas atmosphere of 50 hPa to 200 hPa are proposed.

  In Patent Document 2, the phenomenon of carbide decomposition or oxidation in a high-temperature heat source, such as carbide cermet particles, is minimized and the kinetic energy of the heat source is used to maximize the flight speed of the carbide particles. A high-speed flame spraying method that shortens the exposure time (temperature) of the particles to the limit is proposed.

  As described above, the quality of the thermal spray coating and the thermal spraying apparatus have been sufficiently studied. However, the examination of the film deposition process of the thermal spray coating is still insufficient. For example, some of the spray particles introduced into the thermal spray heat source completely melt, while others remain unmelted. When these particles are deposited on the surface of the substrate, mutual fusion occurs. Since it becomes incomplete or uneven, there is a problem that voids (pores) are inevitably generated and become apparent as pores of the film.

For example, according to Patent Document 3, it is clarified that Al ₂ O ₃ or Y ₂ O ₃ sprayed coating formed by the low pressure plasma spraying method has pores of about 0.2 to 7%. ing. That is, most of these pores exist as penetrating pores (pores extending from the outside of the coating to the surface of the substrate), and therefore provide a corrosive gas or fluid infiltration path in the environment of use. As a result, the corrosion of the surface of the base material proceeds, causing a decrease in the bonding force between the film and the base material, which causes peeling.

  As described above, since the sprayed coating inevitably has pores, it is encouraged to perform a sealing treatment after the film formation. For example, JIS H 9302 ceramic spraying work standard describes a method in which after a ceramic spray coating is formed, an inorganic or organic polymer sealing agent is applied or sprayed on the surface to fill the pores. ing.

Moreover, there are the following proposals as a method and a sealing agent for sealing the pores of the thermal spray coating.
(1) Patent Documents 4 to 6 disclose a method of sealing using an organic polymer material such as a silicone compound having a corrosion resistance, a silicon compound such as ethyl silicate, or a synthetic resin.
(2) In Patent Documents 7 and 8, a thermal spray coating is immersed in an electrolytic solution containing a non-metallic compound such as a metal alkoxide or metal oxide particles, then electrolyzed, and the coating is made using the principle of electrophoresis. A method is disclosed in which a solute component or oxide particles are filled in the surface or pores of the material and then heated and fired.
(3) Patent Document 9 discloses a technique in which an organic polymer agent that is cured by visible light is applied to the surface of a thermal spray coating, the pores are filled and sealed, and cured by natural light.
(4) In Patent Document 10 relating to the proposal of the inventors, an amorphous film mainly composed of carbon and hydrogen is applied to the surface of the sprayed coating after irradiating the surface of the sprayed coating with high energy such as an electron beam or a laser beam. A method of forming a coating is disclosed.
(5) Further, Patent Document 11 discloses a technique in which the surface of the thermal spray coating is irradiated with high energy such as an electron beam or a laser beam to melt the thermal spray particles in the vicinity of the surface and thermally eliminate the pores. Is disclosed.

  Conventionally, the following surface treatment techniques have been proposed in order to apply the thermal spray coating having the characteristics and technical background of the coating as described above as a corrosion-resistant coating such as a member for a semiconductor processing apparatus.

  That is, in processing equipment such as dry etcher, CVD, PVD, etc. used in semiconductor processing and liquid crystal manufacturing processes, processing is required due to the need for microfabrication and higher accuracy associated with higher integration of substrate circuits such as silicon and glass. Higher cleanliness has been demanded as an environment. On the other hand, for various processes for microfabrication, highly corrosive harmful gases such as fluorides and chlorides or aqueous solutions are used. Therefore, the members disposed in these processes have a high corrosion wear rate, and as a result, there is a concern about the generation of corrosion products and secondary environmental contamination due to their scattering.

Semiconductor devices are mainly composed of compound semiconductors composed of Si, Ga, As, P, etc., and many of the manufacturing processes belong to so-called dry processes that are processed in vacuum or reduced pressure. In these environments, various processes such as film formation, impurity implantation, etching, ashing, and cleaning are repeatedly performed. As an apparatus belonging to such a dry process, an oxidation furnace, a CVD apparatus, a PVD apparatus, an epitaxial growth apparatus, an ion implantation apparatus, a diffusion furnace, a reactive ion etching apparatus, piping attached to these apparatuses, a supply / exhaust fan, There are parts and parts such as vacuum pumps and valves. In these devices, the use of highly corrosive chemicals and gases as shown below is known. Basically, 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 , SiH ₂ Cl ₂ , Chloride such as SiCl ₄ , HCl and Cl ₂ , bromide such as HBr, NH ₃ , Cl ₃ F and the like are also frequently used.

In the above-described 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 become highly corrosive atomic or ionized F, Cl, Br, and I, and have a great effect on fine processing of semiconductor materials. On the other hand, fine particles of SiO ₂ , Si ₃ N ₄ , Si, W, and the like that are removed by the etching process float from the surface of the semiconductor material subjected to the plasma process (particularly plasma etching process) in the environment. There is a problem in that they adhere to the surface of the device during or after processing, and the quality of the device is significantly reduced.

One of these countermeasures has conventionally been surface treatment with aluminum anodic oxide (alumite). In addition, oxides such as Al ₂ O ₃ , Al ₂ O ₃ .TiO ₂ , Y ₂ O _3, etc., and oxides of Group IIIa metals of the periodic table are sprayed, vapor deposition (CVD, PVD), etc. There are techniques for coating the surface of a device member or using it as a sintered material (Patent Documents 12 to 16).

More recently, plasma erosion resistance is improved by irradiating the surface of the sprayed coating of Y ₂ O ₃ or Y ₂ O ₃ —Al ₂ O ₃ with a laser beam or an electron beam to remelt the surface of the sprayed coating. Techniques for improvement are also disclosed (Patent Documents 17 to 20).

For example, YF ₃ (yttrium fluoride) is used as a material that surpasses the plasma erosion resistance of conventional Y ₂ O ₃ coatings as a means to raise the cleanliness of the manufacturing environment of high-performance semiconductor processing to the limit. The method to apply in is proposed. Specifically, a YF ₃ film is coated on the surface of a sintered body such as YAG or an oxide of a group IIIa element of the periodic table (Patent Documents 21 and 22), Y ₂ O ₃ , Yb ₂ O ₃ , YF A method using a mixture such as ₃ as a film forming material (Patent Documents 23 and 24), and a method using YF ₃ as a film forming material by a thermal spraying method (Patent Documents 25 and 26) are seen.

Japanese Patent Laid-Open No. 1-139749 Japanese Patent Laid-Open No. 9-67661 JP 2001-164354 A Japanese Patent Laid-Open No. 54-32422 JP-A-57-70275 JP-A 64-62453 JP-A-62-260096 JP 7-41927 A JP-A-5-106014 Japanese Unexamined Patent Publication No. 7-32194 JP-A-10-306363 Japanese Patent Publication No. 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 JP 2002-293630 A JP 2002-252209 A JP 2008-98660 A Japanese Patent Laid-Open No. 2005-243988 JP 2004-197181 A JP 2002-037683 A

In particular, the present invention aims to solve the following technical problems of the prior art regarding the fluoride spray coating.
(1) Fluoride spray coatings such as YF ₃ and EuF ₃ formed by thermal spraying, and Ni, Ni-Cr alloy spray coatings have relatively good durability in plasma etching environments using halogen gas. Show. However, a common problem with sprayed coatings is the presence of through pores. For this reason, through-holes that are less likely to cause problems in dry processes such as plasma etching are often fatal defects in wet processes.

(2) When the through hole exists, for example, there are the following problems. That is, even in a semiconductor processing apparatus, even if it is dedicated to a dry process such as plasma etching, fine particles cut out by etching are accumulated in the apparatus as the processing progresses, and this is the cause. Production of high-quality semiconductor processed products becomes difficult. For this reason, it is often necessary to clean the apparatus with acid, alkali, pure water or the like. During the cleaning operation of such an apparatus, these aqueous solutions penetrate into the inside through the through-holes on the surface of the film, chemically corrode the base material and the undercoat of the film, and the durability of the covering member is inferior. There are drawbacks.

(3) As a technique for improving the disadvantages of the thermal spray coating, the surface of the oxide ceramic thermal spray coating is irradiated with high energy such as an electron beam or a laser beam, and the thermal spray particles constituting the thermal spray coating are used. A method is known in which through-pores are eliminated by melting and fusing each other. However, when the remelting technology of sprayed coating by high energy irradiation is applied to fluoride sprayed coating, the surface of the coating is “cracked” by the volume shrinkage phenomenon in the cooling process after remelting of the sprayed particles. Will occur. And since this “crack” plays the role of a new through-hole, there is a problem that it is not possible to prevent the infiltration of the chemical solution / cleaning water for cleaning work, which is also performed in the case of a wet process or a dry process. Arise.

(4) In the method of spraying fluoride particles such as YF ₃ , AlF ₃ , and MgF ₂ , gas plasma and a fossil fuel combustion flame are decomposed in a heat source to generate F ₂ gas and fluoride gas. For this reason, there are problems that a large number of through-holes are generated in the sprayed coating, and internal entry of corrosive components cannot be prevented.

(2) After a ceramic sprayed coating such as Y ₂ O ₃ is formed, the surface of the coating is fluorinated to produce a thin film such as YF _{3 on} the surface of Y ₂ O ₃ particles. The through pores remain in the state at the time of film formation. As a result, although the halogen corrosion resistance is improved, it is easy to enter the inside of cleaning water, etc., so there is a problem that the service life is short due to the occurrence of corrosion inside the coating and the early peeling phenomenon of the sprayed coating resulting from the corrosion. is there.

An object of the present invention is to prior art, particularly to solve the aforementioned problems fluoride sprayed coating are having such YF _3. That is, it is possible to prevent the corrosion resistance of the fluoride sprayed coating due to the through pores from being lowered, and to improve the halogen resistance of the fluoride sprayed coating to improve the durability (lifetime).

  Therefore, in summary, in the present invention, a non-conductive fluoride spray coating is formed on the surface of the conductive substrate, and halogen corrosion resistance and plasma erosion resistance are formed in the through-holes in the fluoride spray coating. We propose a method of converting to a cermet composite film composed of fluoride and nickel by filling nickel (Ni), which is excellent in properties, by electroplating and sealing.

  That is, in the present invention, a non-conductive fluoride is formed on the surface of a base material made of a conductive metal (alloy) or the like by a thermal spraying method, and then the resulting porous fluoride thermal spray coating is electroplated with nickel. Electroplating is carried out by energizing the base material immersed in the liquid and coated with the porous fluoride spray coating as a cathode. By this plating treatment, the fluoride sprayed coating begins to deposit nickel plating metal on the surface of the base material from the plating solution that has penetrated into the coating from the through pores in the coating. Nickel deposited on the surface of the substrate grows toward the surface side of the film while selectively selecting the through-hole part of the film, and finally, all the through-hole parts of the fluoride sprayed film are formed on the substrate side. By being filled with nickel-plated metal that grows from the above, the porous fluoride sprayed coating is transformed into a dense fluoride cermet composite coating. The present invention is a technology developed using such a phenomenon.

  To use the above phenomenon, (1) the base material is conductive, (2) the fluoride spray coating is non-conductive, and (3) the fluoride spray coating is porous and is based on the surface. (4) It is necessary that the metal deposited by the electroplating method has corrosion resistance, particularly halogen resistance, and the present invention proposes a technique having these four conditions. .

That is, the present invention provides a conductive base material in which a conductive metal film is coated on the surface of a metal or non-conductive base material, and a coating solution of 1 × 10 ⁵ Ωcm or more in the plating solution formed on the base material surface. be those obtained by spraying the non-conductive fluoride showing the electrical resistivity, and porosity to 0.2～20Vol% der Ru porous fluoride thermal spray coating including the through pores and open pores And a fluoride-based cermet composite film having a structure in which the through-pores in the sprayed coating are filled and sealed with nickel-plated metal, and is used in a fluorine-based gas plasma environment of a semiconductor processing apparatus, and an acid, an alkali, The present invention proposes a fluoride cermet composite film covering member for a semiconductor processing apparatus , which is a member used in an environment cleaned with pure water.

In addition, the present invention is used in a fluorine-based gas plasma environment of a semiconductor processing apparatus in which a surface of a metal or non-conductive substrate is coated with a conductive metal film, and is cleaned with acid, alkali, or pure water. On the surface of a conductive substrate used in the environment , a non-conductive fluoride exhibiting an electrical resistivity of 1 × 10 ⁵ Ωcm or more is sprayed in the plating solution to form a coating of the fluoride sprayed coating, The non-conductive fluoride was obtained by immersing a substrate coated with the porous fluoride sprayed coating having a porosity of 0.2 to 20 vol% including through-holes and open pores in an electro-nickel plating solution. The nickel plating metal is deposited from the electroplating nickel solution that has penetrated into the pores inside the coating from the open pores and other open pores of the spray coating, and the nickel plating metal is filled into the pores and gaps of the fluoride spray coating. To seal And by, the porous non-conductive fluoride sprayed coating, fluoride cermet composite coating film to be changed in acid or alkali, semiconductor processing device for fluoride cermet, characterized in that to obtain a member which is washed with pure water A method for producing a composite film-coated member is proposed.

In the present invention,
(1) A conductive metal / alloy undercoat is interposed between the conductive substrate and the fluoride-based cermet composite film,
(2) The non-conductive fluoride sprayed coating is a fluoride of a lanthanoid metal element having atomic numbers 57 to 71 in the periodic table of Y and elements,
( 3 ) The undercoat applied to the surface of the conductive base material is at least one metal / alloy selected from Al, Al—Zn, Ni, Ni—Al, Ni—Cr, and Ni—Cr—Al. Using
( 4 ) The non-conductive fluoride spray coating and the cermet composite coating have a thickness of 30 to 500 μm, and the undercoat has a thickness of 10 to 150 μm.
( 5 ) The non-conductive fluoride sprayed coating is formed by a coating method selected from an atmospheric plasma spraying method, a low pressure plasma spraying method, and a high-speed flame spraying method,
( 6 ) The undercoat is coated by any one of spraying methods selected from arc spraying, flame spraying, high-speed flame spraying, and plasma spraying,
Is considered to be a more preferable solution.

  According to the present invention, the following effects can be expected. For example, a through-hole portion of a non-conductive fluoride sprayed coating formed on the surface of a conductive substrate is filled with nickel-plated metal deposited by electroplating and sealed, whereby fluoride and metal Therefore, it is possible to improve the property of being porous, poor in ductility, easily cracked and weak against heat and mechanical shock. Furthermore, both fluoride and nickel (Ni) are useful as a coating member for semiconductor processing equipment because they are both excellent in corrosive action by halogen gas and plasma erosion resistance.

Further, according to the present invention, the following effects can be expected.
(1) Since the nickel electroplating process is performed on the non-conductive fluoride sprayed coating formed so as to cover the surface of the conductive substrate, the nickel-plated metal deposited from the plating solution only on the through pores of the sprayed coating As the fluoride sprayed coating is cermetized (composited), the coating is sealed and the surface of the membrane is densified, preventing the penetration of cleaning water and other materials into the coating. It becomes possible to prevent corrosion of the base material due to cleaning water and peeling of the coating film accompanying it.

(2) From the plating solution into the through-holes and open pores where the plating solution that is three-dimensionally present inside the fluoride spray coating can enter, or the gaps (voids) between the incompletely joined portions of the spray particles. Since the deposited nickel-plated metal can be filled, sealing can be surely achieved and the mutual bonding force of particles can be improved.

(3) Nickel plating metal deposition starts from the surface side of the conductive base material and follows the process of progressing toward the coating surface over time. Since all the gaps existing at the boundary are filled and sealed sequentially from the base material side, a method of applying inorganic and organic sealing agents prescribed in the JIS H9302 ceramic spraying work standard to the coating surface Compared to the above, the sealing effect is large and reliable.

(4) The nickel plating solution that penetrates into the voids of the coating penetrates into the voids (through pores and open pores) that exist three-dimensionally in the non-conductive fluoride sprayed coating, and deposits nickel from the plating solution. As the portion is filled, adhesion and growth occur in an electrochemically coupled state with the base material, so that the adhesion of the entire fluoride sprayed coating to the base material is improved.

(6) Since the nickel plating metal filled in the through-hole portion of the fluoride sprayed coating forms a thin film of NiF ₂ having excellent fluorine corrosion resistance when in contact with fluorine gas or fluoride gas (containing liquid), The outer surface portion of the film (the portion that comes into contact with a halogen gas such as fluorine gas) is apparently covered with fluoride, and becomes a coating member having excellent corrosion resistance and plasma erosion resistance.

(7) Since the fluoride sprayed coating has a high electrical resistivity, it tends to be charged with negative static electricity in vacuum or dry air, attracting fine particles and contaminating the coating surface. In this respect, the nickel filled in the through pores in the sprayed coating is effective in discharging (discharging) the static electricity of the fluoride sprayed coating and preventing the action of collecting fine particles.

It is the schematic diagram which showed the flow of the process for enforcing the method of this invention. It is a basic diagram of the electro nickel plating apparatus which shows one Embodiment of this invention method. It is a photograph showing a cross-section microstructure of YF ₃ spray coating after electrolytic nickel plating. YF ₃ spray coating nickel plating deposition conditions is a photograph showing the microstructure of the film cross-section showing the (distribution). 6 is a schematic diagram of a corrosion test apparatus used in Example 4. FIG.

Hereinafter, preferred embodiments of the present invention will be described. FIG. 1 shows a process flow for carrying out the method of the present invention. Details of the configuration of the present invention will be described below in the order of the steps.
(1) Selection of base material The base material which can be used by this invention is a metal material which has electroconductivity (electrical conductivity). For example, Al and its alloys, Ti and its alloys, various alloy steels including stainless steel, carbon steel, nickel and their alloys are suitable. A base material in which a nickel plating film is formed on the surface of a steel material may be used. For pre-treated substrates such as glass, quartz, plastic, and ceramic sintered bodies, after pre-treatment, a metal for imparting conductivity by electroless plating, CVD, PVD, etc. A thin film coated and only the surface of the base material used as an electrical conductor can also be used as the base material of the present invention.

(2) Coating of fluoride spray coating on substrate surface Prior to forming a non-conductive fluoride spray coating on the surface of the conductive substrate, the ceramic spray coating standard specified in JIS H 9302 is used. It is preferable to carry out in compliance. For example, after removing rust and oils and fats on the surface of the base material, after grinding with abrasive particles such as Al ₂ O ₃ and SiC, and roughening the surface, or after applying a conductive undercoat of metal directly on the surface A non-conductive fluoride spray coating is formed on them.

  As a method for forming the fluoride spray coating, an air plasma spray method, a low pressure plasma spray method, a water plasma spray method, a high-speed flame spray method, an explosion spray method, or the like is preferably used.

  For the conductive undercoat, arc spraying, flame spraying, and the like can be used in addition to the various spraying methods described above, and the type of spraying method is not particularly limited.

(3) Non-conductive Fluoride Spray Material The spray material for forming a fluoride spray film used in the present invention must be non-conductive and excellent in halogen resistance. As the fluoride having both properties, fluoride particles of lanthanoid elements belonging to Y of the periodic table IIIa of elements and atomic numbers 57 to 71 are used. That is, as the metal elements having atomic numbers 57 to 71, 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), lutetium (Lu), and the like.

The electrical resistivity (Ωcm) of these group IIIa Y and tantanoid metal element fluorides has a high volume resistance such as YF ₃ 6 × 10 ¹⁰ , CeF ₃ 3.7 × 10 ^{12, and the} like. It can be used as a fluoride spray coating material. According to the knowledge of the inventors, when the substrate on which the fluoride spray coating is formed is immersed in the plating solution and energized, the plating metal is not directly deposited on the surface of the coating (fluoride). Although it serves as a standard for reference, a fluoride showing an electrical resistivity of 1 × 10 ⁵ Ωcm or more is generally preferable.

  As the fluoride spray material in the present invention, it is preferable to use a particle size adjusted to 5 to 80 μm. The reason for this is that fine particles of 5 μm or less are decomposed when heated in a thermal spraying heat source such as plasma, and the particle size is further reduced, so that more particles are scattered than film formation, This is because particles larger than 80 μm have a discontinuous feed rate to the spray gun, and the through pores of the deposited film become large, resulting in a deterioration in film quality.

  The thermal spray coating obtained by thermal spraying the fluoride thermal spray material is preferably applied to a thickness of 30 to 500 μm. The range of 50 to 200 μm is particularly suitable. The reason is that with a film thinner than 30 μm, it is difficult to obtain a film with a uniform film thickness. On the other hand, when it is formed thicker than 500 μm, the residual stress at the time of forming the fluoride film increases, and it is easy to peel off from the substrate. Because.

(4) Features of fluoride spray coating The following are common physicochemical properties of fluoride. That is, this fluoride spray coating has chemical stability against halogen-based gas as compared with metal coatings and ceramic coatings, but the surface energy is small, so the mutual bonding force of fluoride particles constituting the coating and the substrate There is a problem that the adhesion strength of is weak. In addition, since this film has various phenomena such as decomposition (oxidation), vaporization (vaporization), melting and softening in a thermal spray heat source, it proceeds in a very short time (1/500 to 1/1000 seconds). Since it is porous (area ratio 0.2 to 20%) and a large residual stress is generated in the film, the film often peels even if the substrate is slightly deformed. In addition, since the fluoride itself has poor ductility, the film easily “cracks” and, together with the pores generated during the film formation, leads to internal penetration of acid and alkaline cleaning liquids, which causes the corrosion of the substrate. It is easy to become. Therefore, although the corrosion resistance of the fluoride itself is good, there is a problem that the property cannot be effectively used.

  In addition, the fluoride spray coating has a property of being negatively charged like a fluororesin typified by Teflon in a dry environment, and therefore has a property of electrostatically adsorbing fine particles generated in a semiconductor processing environment. For this reason, it may hinder the prevention of contamination.

(5) Formation of Cermet Composite Film by Electro Nickel Plating Treatment In the present invention, this electro nickel plating treatment is extremely important. By this treatment, the non-conductive and porous fluoride spray coating can be changed to a fluoride-based cermet composite coating in a state in which nickel-plated metal is filled in the open pores of the porous fluoride spray coating. At the same time, a dense film can be formed by sealing the pores of the film. The degree of cermetization is set to the porosity (0.2 to 3.0, preferably 5 to 20%) in the fluoride spray coating.

FIG. 2 shows the principle of this nickel electroplating process. In this treatment, a conductive base material 21 coated with a porous non-conductive fluoride spray coating 22 is immersed in a nickel plating solution, the base material 21 is used as a cathode, and nickel of the plating metal 23 is obtained. Is a method of plating by applying direct current to the anode as a positive electrode. In such a plating process, nickel eluted from the anode is eluted into the plating solution as ions. On the other hand, on the surface of the base material of the cathode, an electrochemical reaction occurs in which nickel ions are precipitated in the form of metallic nickel from the plating solution that has entered from the open pores of the porous non-conductive fluoride spray coating. For example, the deposition amount of the plating metal is basically substantially proportional to the amount of electricity supplied, but in the present invention, the current density is about 0.5 A / dm ^{2 to} 10 A / dm ² , preferably lA / dm ^{2 to} 5 A / Plating treatment is preferably performed using a direct current power source of about dm ² and a temperature (room temperature) of about 20 ° C. to 60 ° C. Examples of typical plating bath compositions that can be used in the present invention are shown in Table 1.

  In this electro nickel plating treatment, the plating time varies depending on the thickness of the fluoride sprayed coating and the porosity, but when the purpose is to fill the nickel plating metal into the pores, as described above, after the energization, the deposition is performed. The nickel plating metal deposits in the open pores of the fluoride spray coating and grows while filling this portion, and the end point is observed by observing the state in which the plating deposition metal (Ni) is exposed to the fluoride coating surface from the outside. Judgment. That is, the state corresponding to this determination time is a standard for completing the filling of the pores.

  Regardless of the plating solution, the fluoride spray coating itself of the present invention is chemically stable and does not elute. Moreover, since the fluoride sprayed coating used in the present invention is non-conductive, the plating metal nickel deposited on the surface of the fluoride sprayed coating does not cover the surface to become a plated film. In spite of this, if the plating solution is strongly acidic and the fluoride spray coating may be dissolved, it is recommended to use a plating solution that is almost alkaline or neutral. Further, an organic solvent or an organic molten salt electrolyte plating solution can be used instead of the aqueous solution.

  In the present invention, nickel, which is a plating metal, is deposited and sealed in the pores of the non-conductive fluoride spray coating, and the reason for forming the cermet is through pores and open pores in the fluoride spray coating, As a result of the plating solution penetrating into the pores from the voids and sequentially reaching the surface of the conductive substrate or the undercoat surface existing as a cathode through these pores, they are electrically connected and are as follows: A reaction is caused to deposit a plated metal.

Metal (Ni) ions in the plating solution → Electrons are emitted from the cathode surface and deposited as metal (Ni).

  In such an electric nickel plating process, when energization is continued, nickel, which is a plating metal, is first deposited in the film pores on the surface side of the conductive base material. In particular, there is a plating solution so that nickel deposits sequentially from the substrate surface toward the surface of the fluoride spray coating, and continues to grow and fill most of the voids in the fluoride spray coating. In most of the voids (excluding completely closed pores), nickel, which is a plating deposited metal, is deposited and filled and sealed. In this case, since the voids in the fluoride sprayed coating, that is, through pores and open pores, exist three-dimensionally (three-dimensionally) in the thickness direction of the coating, all of them are formed by plating deposited nickel. As a result of the continuous filling, the fluoride sprayed coating after the plating is substantially filled with the plating deposited nickel at least for the open pores, thereby substantially having a cermet structure. Moreover, since nickel-plated metal particles are bonded to the base material by electrochemical action in the pores of the non-conductive fluoride sprayed coating, not only the adhesion to the base material is improved, but also between the fluoride particles. The fluoride cermet composite film that plays a major role in improving the mutual bond strength of the film and improves the strength of the entire film.

  In this electro nickel plating treatment, when the plating time is extended, almost all pores (voids) existing inside the fluoride spray coating are filled and sealed, and eventually reach the surface of the spray coating to cover it. Until. The nickel-plated metal is initially deposited in the form of fine particulate nickel from the lower layer portion on the substrate side of the fluoride spray coating. However, since the plated nickel-plated metal particles cannot be confirmed on the surface of the film having no through pores, according to the present invention, it is possible to visualize the through pore portion, which has been difficult with the prior art.

  As is well known, the amount of nickel deposited by the electrolytic nickel plating process is governed by the electrochemical equivalent of nickel. In other words, the deposition amount (precipitation rate) of nickel-plated metal is proportional to the energization amount, although it has a value specific to each metal, and if it is the same energization amount, it is proportional to the energization time. By controlling, it is possible to adjust the filling amount in the voids inside the coating and the amount of metal formed by coating on the coating surface.

FIG. 3 shows a cross-sectional microstructure of a fluoride (YF ₃ ) sprayed coating after electrolytic nickel plating, that is, a cermet composite coating. Nickel-plated metal that has started to deposit from the substrate surface gradually grows toward the surface of the film through the unbonded portion (void portion) of the YF ₃ particles, and a part of the nickel-plated metal is already exposed on the surface. It is in.

FIG. 4 shows the distribution of the nickel-plated metal particles on the surface portion of the YF ₃ sprayed coating, that is, the cermet composite coating. Here again, the number of the particulate nickel-plated metal increases as the energization time is extended, and finally the surface of the coating is completely covered. In the present invention, when the state as shown in FIG. 4 (b) is reached, the end point of the plating process is set. The reason is that the voids inside the film in the above state are almost filled with nickel-plated metal. This is because there is a high possibility that

As can be understood from the above-described representative embodiments of the present invention, it is more preferable to adopt the following configuration.
(1) The non-conductive fluoride sprayed coating is a coating having a porosity including through pores and open pores of 0.2 to 20 vol%, preferably 5 to 20 vol%. This is because it is difficult to form a coating of less than 0.2 vol% by the thermal spraying method, whereas when it exceeds 20 vol%, the performance as a fluoride spray coating cannot be sufficiently exhibited.
(2) A conductive metal undercoat is provided between the conductive substrate and the nonconductive fluoride sprayed coating, that is, the cermet composite coating, as necessary. This is effective in improving the adhesion between the fluoride spray coating and the substrate. The undercoat formed on the surface of the substrate is preferably 10 to 150 μm thick.
(3) As the undercoat, it is preferable to use at least one metal (alloy) selected from Al, Al—Zn, Ni, Ni—Al, Ni—Cr, Ni—Cr—Al, and the like.

Example 1
In this example, a coating of YF ₃ , CeF ₄ and EuF ₃ was directly applied to the surface of an SS400 steel test piece (size: width 20 mm × length 30 mm × thickness 3.2 mm) by an atmospheric plasma spraying method: film thickness: 120 μm. In this case, a basic fluoride sprayed coating is formed, and this is electroplated with nickel. In addition, using a commercially available inorganic silicon sealing agent applied to the coating surface as a variable factor, the presence and extent of through-pores in the coating was determined by the ferroxyl test method specified in the test method for JIS H8666 ceramic spray coating. investigated.

(1) Feroxyl test (salt spray test)
In this ferroxyl test, 10 g of potassium hexacyanoferrate (III) and 15 g of sodium chloride were dissolved in 1 liter of distilled water, and this was sufficiently impregnated into a filter paper for analysis. After standing for 30 minutes, the filter paper was peeled off, and the presence or absence of blue spots on the filter paper surface was visually judged. According to this method, if there are through-pores in the amorphous membrane, the ferroxyl test solution penetrates, reaches the iron base interface and generates iron ions, and this reacts with potassium hexacyano (III) acid, and filter paper. Can be determined by generating blue spots on the surface of the surface.

(2) Test results Table 2 shows the test results. As is clear from this result, those in which the fluoride sprayed coating was directly formed on the SS400 steel substrate (No. 2, 5, 8) produced a large number of blue spots and was in a very porous coating state. It is recognized that In the films (Nos. 3, 6, and 9) in which commercially available inorganic silicon compound-based sealing agents belonging to the prior art are applied to these fluoride spray coatings, the number of occurrences of blue spots is smaller than the former. Although it is halved, a complete sealing effect is not obtained.
On the other hand, for the cermet composite coating (No. 1, 4, 7) in which the surface of the fluoride sprayed coating was nickel-plated, almost no blue spots were generated, and the through pores of the coating were deposited from the plating solution. It was revealed that it was filled with nickel and prevented from entering the Ferroxy Sole test solution.

(Example 2)
In this example, YF ₃ , DyF _3, and CeF ₄ were each formed into a thickness of 100 μm directly on the surface of a test piece of SS400 steel (width 20 mm × length 30 mm × thickness 5 mm) by atmospheric plasma spraying. After the film was formed, electro-nickel plating was applied as a secondary treatment of the film, and the corrosion resistance in halogen vapor was investigated for those coated with a commercially available inorganic silicon sealing agent.

(1) Corrosion test method (a) The corrosion test using HCl vapor is carried out by adding 100 ml of 30% HCl aqueous solution to the lower part of a desiccator for chemical experiments and suspending a test piece on the upper part of the HCl vapor generated from the HCl aqueous solution. The method of exposure was adopted. The corrosion test temperature is 30 ° C. to 50 ° C., and the time is 96 hours.
(B) In the corrosion test with HF vapor, 100 ml of an HF aqueous solution was placed at the bottom of an SUS316 autoclave, and a test piece was hung on the top to suspend the corrosion test with HF vapor. The corrosion test temperature is 30 ° C. to 50 ° C., and the exposure time is 96 hours.

(2) Test results Table 3 shows the corrosion test results. As is clear from this result, red rust was generated over the entire surface of the films (Nos. 2, 5, 8) in which the YF ₃ , DyF ₃ and CeF ₄ films were directly formed on the surface of the SS400 substrate. That is, it is clear that the fluoride spray coating formed by the atmospheric plasma spraying method is easily corroded by halogen-based acid vapors such as HCl and HF, and has a poor effect of preventing the substrate from being corroded. Even when the surface of such a film is sealed with a market version of a sealing agent (No. 3, 6, 9), complete sealing is not observed, and red rust is not generated in any film. Not recognized. In particular, the generation of red rust was observed to the extent that the practical function was lost for HF vapor.
On the other hand, regarding the cermet composite coating (No. 1, 4, 7) in which the electroplating treatment was applied to the fluoride sprayed coating, the occurrence of red rust was not observed, and it was confirmed that it exhibited sound corrosion resistance. This result is considered to be due to the fact that the through pores where the fluoride sprayed coating is present are filled with the electro nickel plating metal to form a substantially complete sealed state.

Example 3
In this example, the plasma erosion resistance of the fluoride cermet composite coating according to the present invention was investigated. JIS H4000 specified 3003 alloy (dimensions: 50 mm x 50 mm x 5 mm thickness) is used as a base material, and the surface is coated with YF ₃ with a thickness of 80 μm using atmospheric plasma spraying or reduced pressure plasma spraying. Formed. In forming the YF ₃ sprayed coating, a Ni-20 mass% Cr alloy with an undercoat thickness of 80 μm was also prepared. The thus-formed YF ₃ sprayed coating was subjected to electro nickel plating under the same conditions as in Example 2 to obtain a cermet composite coating. Moreover, the plasma erosion resistance of a B ₄ C sprayed coating as a coating of the comparative example was also examined under the same conditions.

(1) Plasma gas atmosphere and flow rate condition A mixed gas of (100) / Ar (1000) / O ₂ (10) and CF ₄ were flowed at a flow rate of 1 cm ³ per minute.
(2) Plasma irradiation conditions High frequency power: 1300 W, pressure: 133.3 Pa
(3) Irradiation method and irradiation time In the plasma erosion test, after the other portions were masked so that the fluoride sprayed coating surface was exposed to a size of 10 mm × 10 mm, plasma irradiation was continued for 20 hours. The erosion damage amount was measured as a reduced thickness, and evaluated by measuring with a stylus type roughness meter.

(4) Test results Table 4 shows the test results. As is clear from this result, the B ₄ C sprayed coating (No. 5) of the comparative example has a large erosion damage amount of 14 μm even when nickel plating is applied, and it is seen that the plasma erosion resistance is poor. On the other hand, the YF ₃ sprayed coating has improved plasma erosion resistance as compared with the BC coating even in the film formation state (No. 2, 4), but its effect is low. However, the cermet state of the YF ₃ sprayed coating is nickel-filled, sealed with nickel, and the amount of erosion loss is drastically reduced. The loss amount is only 1 μm and excellent plasm erosion resistance is achieved. confirmed. The results of this example show that the YF ₃ cermet composite coating formed by the atmospheric plasma spraying method and the low pressure plasma spraying method has the same amount of damage, and is excellent regardless of the presence or absence of the undercoat. It was proved that the plasma erosion resistance was exhibited.

Example 4
In this example, after the nickel spray treatment was performed on the lanthanoid metal fluoride spray coating, the alkali immersion test and the corrosion resistance of the fluoride spray coating in an activated halogen gas were investigated.

(1) Test coating As the base material, Al alloy (A13003) (dimensions: 50 mm x 50 mm x 5 mm) and SUS410 steel (dimensions: 30 mm x 20 mm x 3.2 mm) were used. A 110 μm fluoride sprayed coating was formed directly on the substrate surface by atmospheric plasma spraying.
Film material: ScF ₃ , EuF ₃ , YF ₃ , ErF ₃
In addition, as a thermal spray coating of the comparative example, Y ₂ O ₃ and A1 ₂ O ₃ atmospheric plasma spray coating were tested under the same conditions.
Moreover, the fluoride sprayed coating after film formation was carried out under the conditions of 45 ° C. and lA / dm ² using the Watt bath described in Table 1.

(2) Corrosion damage test method
(i) Alkaline immersion test A test film formed on an Al alloy substrate is immersed in a 5% NaOH aqueous solution at 40 ° C. for 1 hour, and the presence or absence of hydrogen gas bubbles generated from the surface of the film is visually observed. Thus, the denseness of the fluoride spray coating was investigated. In this test, a chemical resistant paint was applied to the exposed portion of the base material, and an aqueous NaOH solution was prepared so as to penetrate from the surface of the coating. This is because if the NaOH aqueous solution enters from the pores of the film, it reacts with the base material (Al alloy) to generate hydrogen gas, so that it is possible to determine whether the film is sealed.
Al + NaOH + H ₂ O → NaAlO ₂ + 3 / 2H ₂
Further, the plasma erosion resistance test was evaluated under the same conditions as in Example 3.

(ii) Corrosion test with activated halogen gas FIG. 5 shows a schematic configuration of the corrosion test apparatus. In this test, after the test piece 51 is allowed to stand inside a stainless steel tube 53 provided in the center of the electric furnace 52 (specifically, on the test piece setting table 56), the corrosive gas 54 is removed from the stainless steel tube 53. This was done by flowing from the left side. A quartz discharge tube 55 provided in the middle of the stainless steel tube 53 is loaded with a microwave having an output of 600 W so as to promote activation of the corrosive gas.

The activated corrosive gas is introduced into the electric furnace, corrodes the test piece 51 stationary on the test piece installation table 56, and then is discharged from the right side of the stainless steel pipe 53 to the outside of the system. Using the corrosion test apparatus having such a configuration, a 10-hour corrosion test was performed while flowing a test piece temperature of 120 ° C., a corrosive gas CF ₄ of 150 ml / min, and O ₂ of 75 ml / min. The feature of this corrosion test is to evaluate the corrosion resistance in an environment where corrosive CF ₄ gas is excited by plasma irradiation and changes to a stronger corrosive gas.

(3) Test results The test results are shown in Table 5. This result shows the corrosion resistance of the test film as shown below.
(i) Alkaline immersion test result: Since both the fluoride spray coating and the oxide coating have through-holes peculiar to the fluoride spray coating, when immersed in a 5% NaOH solution, it becomes fine after 3 to 5 minutes have elapsed. Hydrogen bubbles began to be generated. The generation of these hydrogen gases gradually increases with the passage of time, and even if the film itself is excellent in alkali resistance, the base material is corroded by NaOH entering from the through-holes of the film and the durability is poor. There was found.

On the other hand, when the nickel electroplating treatment is applied to the fluoride sprayed coating (No. 1, 3, 5, 7), the through pores are sealed with nickel plating metal. Generation of gas was not recognized, and good denseness was exhibited.
(ii) Bonding of active halogen gas corrosion test: In the film (No. 2, 4, 6, 8, 9, 10) which is not subjected to the electro nickel plating treatment of the comparative example, both the fluoride sprayed film and the oxide film Red rust was observed on the surface. This red rust is considered to be that the corrosion product has grown to the surface of the film as a result of the halogen gas entering from the pores of each film corroding the substrate.

  On the other hand, the cermet composite film (No. 1, 3, 5, 7) obtained by performing the nickel plating treatment is such that the nickel-plated metal is sealed in the through-hole portion where the halogen gas of the composite film enters. Therefore, it is considered that good corrosion resistance was exhibited as a result of hindering the internal penetration of the corrosive gas.

  The technology according to the present invention can be applied to a member for a precision processing apparatus of a semiconductor that requires high halogen corrosion resistance and plasma erosion resistance. Specifically, in addition to the Teppo shield, baffle plate, focus ring, insulator ring, sill ring, bellows cover, electrode, etc., which are disposed in the plasma processing apparatus, using a processing gas containing halogen and its compound, It can be used as a corrosion-resistant film for chemical plant equipment members having similar gas atmospheres.

21 Electroconductive substrate 22 Fluoride spray coating 23 Ni anode 24 DC power supply 51 Test coating specimen 52 Electric furnace 53 Stainless steel tube 54 Corrosive gas 55 Quartz discharge tube 56 Test specimen installation table

Claims (8)

A conductive substrate having a conductive metal film coated on the surface of a metal or non-conductive substrate;
It is obtained by spraying a non-conductive fluoride which is coated on the surface of the base material and exhibits an electrical resistivity of 1 × 10 ⁵ Ωcm or more in a plating solution , and the porosity is a through-pore. to 0.2～20Vol% der Ru porous fluoride sprayed coating comprising open pores, and fluoride-based cermet composite film having a through pores of the solution morphism in the film structure filled sealed by nickel plated metal,
It is a member that is used in a fluorine-based gas plasma environment of a semiconductor processing apparatus and is used in an environment that is cleaned with acid, alkali, or pure water.
A fluoride cermet composite film covering member for a semiconductor processing apparatus . Between the conductive substrate and the fluoride-based cermet composite film, at least one selected from conductive Al, Al—Zn, Ni, Ni—Al, Ni—Cr, and Ni—Cr—Al The fluoride cermet composite film covering member for a semiconductor processing apparatus according to claim 1, wherein an undercoat is interposed. 3. The semiconductor according to claim 1, wherein the non-conductive porous fluoride sprayed coating is a fluoride of a lanthanoid metal element having an atomic number of 57 to 71 in the periodic table of Y and elements. Fluoride cermet composite film covering member for processing equipment . 3. The fluoride for a semiconductor processing apparatus according to claim 2 , wherein the non-conductive fluoride sprayed coating and the cermet composite coating have a thickness of 30 to 500 μm, and the undercoat has a thickness of 10 to 150 μm. Cermet composite coating member. Used in a fluorine-based gas plasma environment of a semiconductor processing apparatus and coated with a conductive metal film on the surface of a metal or non-conductive substrate and used in an environment where it is cleaned with acid, alkali, or pure water On the surface of the conductive substrate, a non-conductive fluoride having an electric resistivity of 1 × 10 ⁵ Ωcm or more is sprayed in the plating solution to form a fluoride spray coating, and then the obtained through-pores A substrate coated with a porous fluoride sprayed coating having a porosity of 0.2 to 20 vol% including open pores is immersed in an electrolytic nickel plating solution, and the open pores of the non-conductive fluoride sprayed coating By depositing nickel-plated metal from the electro-nickel plating solution infiltrated into the pores inside the coating from other open pores, and filling the nickel-plated metal into pores and gaps of the fluoride spray coating to seal The The porous non-conductive fluoride sprayed coating varied fluoride cermet composite coating with acid or alkali, fluoride cermet composite coating film covering member for a semiconductor processing apparatus for and obtaining a member to be cleaned with pure water Manufacturing method. Between the conductive substrate and the fluoride cermet composite film, one or more unders selected from conductive Al, Al—Zn, Ni, Ni—Al, Ni—Cr and Ni—Cr—Al The method for producing a fluoride cermet composite film-coated member for a semiconductor processing apparatus according to claim 5, wherein a coating is interposed. The non-conductive fluoride sprayed coating is formed by spraying a fluoride of Y and a lanthanoid metal element having an atomic number of 57 to 71 in the periodic table of elements. The manufacturing method of the fluoride cermet composite film coating | coated member for semiconductor processing apparatuses as described in any one of. The fluoride for a semiconductor processing apparatus according to claim 6, wherein the non-conductive fluoride sprayed coating and the cermet composite coating have a thickness of 30 to 500 µm, and the undercoat has a thickness of 10 to 150 µm. A method for producing a cermet composite coating member.

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