Plasma-Resistant Component, Method For Manufacturing The Plasma-Resistant Component, And Film Deposition Apparatus Used For Manufacturing The Plasma-Resistant Component
The present invention provides a plasma-resistant component for use in a plasma apparatus, wherein an oxide film is formed on at least part of a surface of a substrate of the component, the oxide film is a deposited oxide film formed as an aggregate of polycrystalline particles, the polycrystalline particles being formed by sinter-bonding of microparticles having an average particle size of 0.05 to 3 μm, and the deposited oxide film has a film thickness of 10 μm or more and 200 μm or less and a film density of 90% or more. Due to above structure, it becomes possible to obtain a plasma-resistant component and a method of manufacturing a plasma-resistant component in which the generation of particles removed from the component is stably and effectively suppressed, and damage such as corrosion and deformation rarely occur during the regeneration process.
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An embodiment of the present invention relates to a plasma-resistant component, a method for manufacturing the plasma-resistant component, and a film deposition apparatus used for the manufacture of the plasma-resistant component.
BACKGROUND ARTConventionally, in a micromachining process in a manufacturing process for a semiconductor apparatus, a liquid crystal display, or the like, usually, fine wiring, electrodes, and the like are formed using the formation of an insulating film of SiO2 or the like by utilizing a sputtering apparatus or a CVD apparatus and the isotropic etching and anisotropic etching of Si and SiO2 by utilizing an etching apparatus.
Generally, in these apparatuses, plasma discharge is used in order to improve film formation speed and etching properties.
For example, as the above etching apparatus, a plasma etching apparatus such as an RIE (Reactive Ion Etching) apparatus is used.
In the RIE apparatus, the interior of the chamber is brought into a low pressure state, and a fluorine-based gas or a chlorine-based gas is introduced into the chamber and turned into a plasma thereby to carry out etching.
Conventionally, among components constituting a plasma etching apparatus, a component to be irradiated with a plasma such as a chamber is devised so that reaction products are not produced. Further, the component is likely to be corroded by exposure to a plasma, and therefore, generally, a film having high plasma resistance and corrosion resistance is formed on a surface of a substrate (base member).
As this type of the film, oxide films comprising yttrium oxide (Y2O3) and aluminum oxide (Al2O3) are generally known. These oxide films are effective in the suppression of the generation of reaction products and the prevention of damage to the component due to plasma attack.
For example, Japanese Patent No. 4084689 (Patent Document 1) describes a Y2O3 film formed by heat-treating a Y(OH)3 sol liquid applied to a substrate, and Japanese Patent Laid-Open No. 2006-108178 (Patent Document 2) describes a thermally sprayed. Al2O3 film.
PRIOR ART DOCUMENTS Patent Documents Patent Document 1: Japanese Patent No. 4084689 Patent Document 2: Japanese Patent Laid-Open No. 2006-108178 SUMMARY OF THE INVENTION Problems to be Solved by the InventionHowever, a thermally sprayed oxide film of yttrium oxide, aluminum oxide, or the like formed by a conventional thermal spraying method is a film in which particles of an oxide such as yttrium oxide or aluminum oxide are deposited, and these particles are formed by the collision of molten particles of an oxide, yttrium oxide or aluminum oxide, with a surface of a substrate and the molten particles are rapidly quenched (cooled) and solidified. Further, the particle size of an oxide powder used in a conventional thermal spraying method is as large as about 5 to 45 μm. Therefore, technical problems of a thermally sprayed oxide film of yttrium oxide, aluminum oxide, or the like formed by a conventional thermal spraying method are that a large number of microcracks are likely to occur due to the thermal expansion difference between the interiors and the surfaces of the oxide films, strain is likely to remain, and the durability of the oxide film is insufficient.
In other words, particles of an oxide such as yttrium oxide or aluminum oxide melted by a thermal spraying heat source collide with a surface of a substrate and deform into the so-called flat shape in which the thickness contracts in the direction perpendicular to the substrate surface and the particles grow and expand in the parallel direction, and then the particles solidify rapidly and are likely to become particles having a flat shape (hereinafter referred to as “particles flattened by melting”) (
At this time, when the average particle size of the oxide powder particles is as large as 5 μm or more, cracks (hereinafter referred to as “microcrack”) mainly observed in the thickness direction perpendicular to the substrate surface occur in the surfaces of the particles flattened by melting, and strain remains in the interiors of the particles flattened by melting.
The above flat shape means a shape having an aspect ratio of 1.5 or more when the aspect ratio (L/t) is calculated from the thickness (t) of the particle in the direction perpendicular to the substrate surface and the length (L) of the particle in the direction parallel to the substrate surface.
When the yttrium oxide film or the aluminum oxide film in such a state is irradiated with active radicals generated by plasma discharge, the active radicals attack the above microcracks, and the microcracks are enlarged, and the microcracks propagate when internal strain is released.
As a result, the thermally sprayed film is damaged and chipped, and particles derived from the thermally sprayed film are likely to be generated, and at the same time, reaction products adhering to the upper surface of the thermally sprayed film peel, and particles derived from the reaction products are likely to be generated.
The generation of particles causes a short circuit or breaking (disconnection) of fine wiring or the like to decrease the yield of a product such as a semiconductor apparatus, and at the same time the cleaning of a plasma apparatus component and the replacement of the component become frequent thereby to cause a decrease in productivity and an increase in film formation cost.
In addition, the particle size of an oxide powder used in a conventional thermal spraying method is as large as about 5 to 45 μm, and therefore the thermally sprayed film formed has a porosity (void ratio) as high as about 15%, and many pores occur, and at the same time the average surface roughness Ra of the thermally sprayed film is as rough as about 6 to 10 μm. The above pore (void) corresponds to a gap between particles, while the above microcracks indicate the cracked surface shapes of particles flattened by melting.
Problems of the use of a plasma apparatus component in which such a thermally sprayed film having many pores and rough surface roughness is formed are that the plasma etching of the substrate proceeds through the pores, and the life of the plasma apparatus component shortens, and at the same time plasma discharge concentrates in the raised (convex) portions of the thermally sprayed film, and the thermally sprayed film becomes brittle, and the amount of particles generated increases.
Further, for example, in recent semiconductor elements, the narrowing of wiring width is promoted in order to achieve a high degree of integration. The narrowing of wiring width reaches, for example, 32 nm, 19 nm, and further 15 nm or less. In wiring narrowed in this manner and an element having the narrowed wiring, even when an extremely minute particle having a size of, for example, about 0.2 μm is mixed, defective wiring (wiring defect), element failure (element defect), and the like are caused. Therefore, in recent years, it is strongly desired to suppress the generation of even extremely minute particles as much as possible.
In addition, when a conventional thermally sprayed film is formed, usually, blasting treatment in which abrasive grains or the like together with particles are blown on a surface of a substrate at high pressure is performed as pretreatment for film formation. However, when such blasting treatment is performed in this manner, residual pieces of the abrasive grains that are blasting materials, are present on the surface of the substrate, or a crushed layer is formed on the surface of the substrate by blasting.
When a conventional thermally sprayed film is formed on such a surface of a substrate on which the blasting material remains or the crushed layer is formed, stress acts on the interface between the substrate and the thermally sprayed film due to the thermal stress of the film due to temperature change in plasma discharge, and the whole thermally sprayed film is likely to undergo film peeling. Particularly, when the pressure of blasting treatment and the abrasive grain size are increased, the occurrence of film peeling is significant. Therefore, the life of a conventional thermally sprayed film also changes greatly depending on the conditions of blasting treatment.
In this manner, problems of a method of forming a conventional thermally sprayed film on a surface of the substrate of a plasma apparatus component are that the thermally sprayed film is likely to be a source of the generation of particles, which decreases product yield, and moreover the life of the thermally sprayed film changes depending on the state of blasting treatment, and variations in quality are large from component to component.
Further, there has been also posed a problem of regeneration treatment in which a film of yttrium oxide like is formed again on the inner wall and inner constituent member of a plasma apparatus component. Namely, in a chemical solution treatment or the blasting treatment used when a film of yttrium oxide or the like formed by thermal spraying is peeled, damage such as corrosion or deformation is caused to the component.
As improvement measures for such problems, with respect to conventional thermal spraying, there is an impact sintering method in which a film having more improved corrosion resistance against a plasma than a film formed by a conventional thermal spraying method is formed by a method in which particles are sprayed at high speed with a high temperature gas such as a combustion flame adjusted to a temperature less than the melting point of particles thereby to form a film while the particles are hardly melted.
However, pores (voids) that are gaps between particles granular deposited without melting, which are not observed in the above particles flattened by melting, are present in particulate portions deposited without melting. Therefore, further densification is difficult, and thus further improvement of corrosion resistance is difficult.
Further, there may be also posed a problem of regeneration treatment in which a film of yttrium oxide like is formed again on the inner wall and inner constituent member of a plasma apparatus component. Namely, in the chemical solution treatment or the blasting treatment used when a film of an oxide such as yttrium oxide formed by the above impact sintering method is peeled, damage such as corrosion or deformation is still caused in the pores (voids) that are the gaps between the above particles though the damage is smaller than in a conventional thermal spraying method.
One embodiment of the present invention has been made in view of the above circumstances and an object of the present invention is to provide a plasma-resistant component in which the porosity of a film can be decreased to increase corrosion resistance and strength, the generation of particles from the film and the peeling of the film are stably and effectively suppressed, and further in regeneration treatment, damage such as corrosion or deformation is less likely to be caused to the member in chemical solution treatment, blasting treatment, or the like used when the film is peeled, and a method for manufacturing a plasma-resistant component, and a film deposition apparatus used for the manufacture of a plasma-resistant component.
Means for Solving the ProblemsIn order to cover a surface of a substrate with a film of an aggregate of dense polycrystalline particles in which particles are sinter-bonded like a sintered body formed by the sintering of a powder, instead of a thermally sprayed film formed by a conventional thermal spraying method, a method and conditions for forming the film, have been diligently studied and examined. As a result, at last the method has been found as a technical finding, and the present invention has been completed on the basis of these findings.
Specifically, when a film of an oxide such as yttrium oxide formed of microparticles having an average particle size of 0.05 to 3 μm is formed, substantially no internal defects, internal strain, or microcracks occur in the oxide such as yttrium oxide constituting this film, and the microparticles are sinter-bonded on a surface of a component substrate to form polycrystalline particles, and a dense film having low porosity is formed as an aggregate of the polycrystalline particles, and therefore the corrosion resistance and strength of the film can be increased.
As a result, the following effects are exerted: the generation of particles from the film and the peeling of the film are stably and effectively suppressed, and the production of reaction products on the surface of the film and the generation of particles from these reaction products can be suppressed, and further in regeneration treatment after the use of the component, damage such as corrosion or deformation is less likely to be caused to the member in chemical solution treatment, blasting treatment, or the like used when the film is peeled.
In order to achieve the film structure of the above film, a method and conditions for forming the film have been found, and the present invention has been completed. The dense polycrystalline particles in which microparticles are sinter-bonded like a sintered body formed by the sintering of a powder include both sinter-bonding by a solid phase sintering mechanism in which particles do not melt, and sinter-bonding by a liquid phase sintering mechanism in which particles melt and are sintered on the particle surfaces or between the particles. The above sinter-bonded polycrystalline particles are particles in which grain boundaries are seen in the particles by microscope observation, rather than single crystalline particles, and the film of the present invention is similarly observed by microscope observation as a film in which these polycrystalline particles are deposited.
In the sinter-bonded dense polycrystalline particles obtained in the present invention, nonparticulate portions in which grain boundaries for separation (distinction) from the outside are not confirmed as observed by microscope observation, for example, in a film formed by an impact sintering method or the like are hardly observed. The area percentage (area ratio) of the above nonparticulate portions in which grain boundaries for separation from the outside are not confirmed in the film is 10% or less when a cross section perpendicular to the substrate plane is observed microscopically.
The area percentage of microparticles having a particle size of 3 μm or less present in the above deposited oxide film according to the present invention is 10% or less when a cross section of the film perpendicular to the substrate plane is observed microscopically, and the area percentage of particles flattened by melting present in the above deposited oxide film is 10% or less when a cross section of the film perpendicular to the substrate plane is observed microscopically. At any rate, the microparticles are hardly observed.
In one embodiment of the present invention, there is provided a plasma apparatus comprising a processing-object holding unit for holding in a chamber a processing object, and a plasma production unit for converting a gas introduced in the above chamber into a plasma, wherein the above processing object is processed using the produced plasma.
An oxide film is formed on the inner wall of the above chamber and the surfaces of constituent members in the above chamber on the side of a region in which a plasma produced by the above plasma production unit is generated. This oxide film is a deposited film comprising particles of an oxide such as yttrium oxide.
The above deposited film is a deposited film formed as an aggregate of polycrystalline particles, the polycrystalline particles being formed by the sinter-bonding of microparticles having a particle size of 0.05 to 3 μm on a surface of the substrate of a component. Further, the deposited oxide film has a film thickness of 10 μm or more and 200 μm or less and a film density of 90% or more.
Microparticles (raw material particles) having a particle size of 3 μm or less are present in the above deposited film at an area percentage of 10% or less. However, the aggregate of polycrystalline particles are densely formed, and therefore the plasma resistance is sufficiently maintained.
Further, the oxide film may be formed with an undercoat film attached. In other words, the oxide film may be formed so that it has a deposited oxide film in which oxide particles are deposited on a conventional thermally sprayed film of an oxide such as yttrium oxide formed as an undercoat film, the total film thickness of the layered film comprising the undercoat film (thermally sprayed film) and the above deposited oxide film is 20 μm or more and 300 μm or less, and the film density of the above deposited oxide film is 90% or more.
Further, the above oxide film may be formed of a three-layered structure comprising an oxide film formed by subjecting a substrate surface to, for example, alumite treatment, an undercoat film formed on the surface of this oxide film, and a deposited oxide film formed on the surface of this undercoat film. In other words, the oxide film has the above deposited oxide film on a conventional thermally sprayed film of an oxide such as yttrium oxide formed as an undercoat film on a substrate surface subjected to oxide film formation treatment, the total film thickness of the layered film comprising the undercoat film and the above deposited oxide film is 20 μm or more and 200 μm or less, and the film density of the above deposited oxide film is 90% or more.
In addition, a film layering apparatus according to the present invention is a film layering apparatus used for manufacture of the plasma-resistant component comprising a substrate and a deposited oxide film covering a surface of the substrate, the apparatus is characterized by comprising a generation chamber for generating a high temperature plasma jet or a high temperature gas by a plasma arc; a raw material slurry supply port for supplying a raw material slurry containing an oxide raw material powder to a central portion of the high temperature plasma jet or the high temperature gas; a fuel supply port for supplying a fuel or an oxygen gas to the generation chamber; a gas supply port for supplying a working gas to the generation chamber; and a spray nozzle for gasifying the raw material slurry with the working gas and the fuel or the oxygen gas, heating an oxide raw material in a gas to a temperature equal to or less than a boiling point and less than a sublimation point of an oxide, and controlling the oxide raw material in a state in which it is sprayed onto a surface of a substrate at a spray speed of 400 to 1000 m/s.
Further, in the film layering apparatus, spray distance between a tip portion of the spray nozzle for spraying the oxide raw material onto a surface of a substrate and the surface of the substrate is preferably 100 to 400 mm. In addition, a content of the oxide raw material powder in the raw material slurry is preferably 30 to 80% by volume.
Advantage of the InventionAccording to the plasma-resistant component, and the method for manufacturing the plasma-resistant component, and the film deposition apparatus used for the manufacture of a plasma-resistant component according to the present invention, there can be provided a component in which the plasma resistance is improved and the generation of particles is stably and effectively suppressed, and a method for manufacturing the same, and a film deposition apparatus used for the manufacture of the same.
Embodiments of a plasma-resistant component, and a method for manufacturing the plasma-resistant component, and a film deposition apparatus used for the manufacture of the plasma-resistant component according to the present invention will be described below. The present invention is not limited by these embodiments.
[Plasma-Resistant Component]The plasma-resistant component according to the present invention is a component comprising a substrate and a film of an oxide such as yttrium oxide covering at least part of a surface of the substrate.
(Substrate)
The substrate used in the plasma-resistant component is, of the component, a member covered with a film of an oxide such as yttrium oxide.
Examples of the substrate include members to be exposed to a plasma and radicals produced in plasma treatment, among the members of plasma-resistant components. Examples of such members may include wafer disposition members, inner wall portions, deposition shields, insulator rings, upper electrodes, baffle plates, focus rings, shield rings, and bellows covers that are members for constituting semiconductor manufacturing apparatuses and liquid crystal device manufacturing apparatuses. Examples of the material of the substrate may include ceramics such as quartz, and metals such as aluminum.
EmbodimentsA film of an oxide such as yttrium oxide used in a plasma-resistant component in an embodiment is a deposited oxide film formed using microparticles (fine particles) having an average particle size of 0.05 to 3 μm and covering a surface of a substrate and is formed of one comprising a single layer of the above deposited oxide film, or one comprising two layers of a thermally sprayed oxide film formed after a substrate is covered with a conventional thermally sprayed film as an undercoat film, and the above deposited oxide film, or one comprising three layers of an oxide film formed by subjecting a substrate surface to oxidation treatment, a conventional thermally sprayed film formed on the surface of the oxide film, and a deposited oxide film covering the surface of the thermally sprayed film.
One of embodiments is a plasma apparatus in which a plasma-resistant component having an oxide film formed of microparticles having an average particle size of 0.05 to 3 μm is mounted, and this oxide film is a deposited film composed of oxide particles.
The above deposited film is a deposited oxide film formed as an aggregate of polycrystalline particles, the polycrystalline particles being formed by the sinter-bonding of microparticles having an average particle size of 0.05 to 3 μm on a surface of the substrate of a component. The film thickness of this deposited oxide film is 10 μm or more and 200 μm or less, and the film density is 90% or more.
Alternatively, in the case of a two-layered structure having the above deposited oxide film on a general thermally sprayed film of an oxide such as yttrium oxide formed as an undercoat film, the total film thickness of the layered film comprising the above undercoat film and the deposited oxide film is 30 μm or more and 200 μm or less, and the film density of the above deposited oxide film is 90% or more.
The purity of raw material particles of an oxide such as yttrium oxide is preferably 99.9% or more. Large amounts of impurities contained in the oxide particles cause the mixing of impurities in a semiconductor manufacturing process. Therefore, more preferably, oxide particles having a purity of 99.99% or more are preferably used.
When a film is formed by a conventional thermal spraying method, coarse particles of an oxide such as yttrium oxide having a particle size of about 5 to 45 μm are ejected and emitted in a molten state and formed into a film in a flat shape, and therefore cracks are likely to occur in the particle surfaces due to rapid cooling and solidification.
On the other hand, in the embodiment of the present invention, microparticles having an average particle size of 0.05 μm to 3 μm are used, and therefore even if they are formed into a film on a substrate, the heat conduction of the particle interiors and surfaces is fast, and stress in the film due to the thermal expansion difference between the interiors and the surfaces in the deposited state hardly occurs, and cracks and the like due to rapid cooling and solidification do not occur.
A fine particle deposited film is a film deposited and formed by heating and high-speed-spraying microparticles with the ejection of a plasma jet or a high temperature gas. Particles heated to a temperature less than the temperatures of the boiling point and the sublimation point are emitted at a high speed of 400 m/s or more and collide with a substrate, and the deposited particles are bonded in their contact portions thereby to form a deposited film.
The bonded particles are microparticles (fine particles) having an average particle size of 3 μm or less, and therefore the heat conduction of the interiors and surfaces of the particles is fast, a stress in the film due to the thermal expansion difference between the interiors and the surfaces in the deposited state hardly occurs, the fine particles are sinter-bonded on the surface of the substrate of the component to form polycrystalline particles, and a deposited film of an oxide such as yttrium oxide that is dense (has high film density) and has strong bonding force can be formed as an aggregate of the polycrystalline particles.
The film thickness of the deposited film of an oxide such as yttrium oxide needs to be 10 μm or more. When the film thickness is less than 10 μm, the effect of plasma resistance is not sufficiently obtained, and on the contrary, film peeling may be caused. The upper limit of the thickness of the deposited oxide film is not particularly limited, but when the deposited oxide film is formed to be excessively thick, a further effect is not obtained, and due to the accumulation of internal stress, cracks are likely to occur, which becomes also a factor of cost increase. Therefore, the thickness of the deposited oxide film is set to 10 to 200 μm, preferably 30 to 150 μm.
The film density (relative density) of the deposited oxide film needs to be 90% or more. The film density is a term opposite to porosity, and a film density of 90% or more has the same meaning as a porosity of 10% or less.
For the method for measuring the film density, the deposited oxide film is cut in the film thickness direction, an enlarged photograph of the cross-sectional structure is taken at a magnification of 500× by an optical microscope, and the area percentage of pores in the photograph is calculated. Then, the film density is calculated by “film density (%)=100−the area percentage of pores.” For the calculation of the film density, an area of a unit area of 200 μm×200 μm is analyzed. When the film thickness is thin, measurement is performed in a plurality of places until the total unit area reaches 200 μm×200 μm.
The film density of the deposited oxide film needs to be 90% or more and is more preferably 95% or more, further preferably 99% or more and 100% or less. When many pores (voids) are present in the deposited oxide film, erosion such as plasma attack proceeds from the pores thereby to decrease the life of the oxide film. Therefore, particularly, it is desired that there are few pores in the surface of the deposited oxide film.
The surface roughness Ra of the deposited oxide film is preferably controlled to be 3 μm or less. When the surface unevenness of the deposited oxide film is large, the plasma attack and the like are likely to concentrate thereto, which may decrease the life of the deposited film. Here, the measurement of the surface roughness Ra conforms to JIS-B-0601-1994. Preferably, the surface roughness Ra is 2 μm or less.
The oxide powder used as a raw material powder using fine particles preferably has an average particle size in the range of 0.05 to 3 μm. In the formed deposited film, the bonding force between the particles is large, the wear due to plasma attack and radical attack is decreased, the amount of particles generated decreases, and the plasma resistance is improved.
When the average particle size of the oxide particles as the raw material powder is more than 3 μm, cracks due to rapid cooling and solidification are likely to occur in the particles in the deposition of the particles on a substrate, which may damage the deposited film to cause cracks.
A more preferred value of the average particle size of the particles is 0.05 μm or more and 1 μm or less. When the average particle size of the particles is less than 0.05 μm, the particles cannot have high speed, and even if they are deposited, they form a low density film, and the plasma resistance and the corrosion resistance decrease.
However, when the particles having an average particle size of less than 0.05 μm account for less than 5% of the total of the oxide particles, film formation is not deteriorated, and therefore a powder containing small particles of less than 0.05 μm may be used.
Next, a method for manufacturing a dry etching apparatus component (plasma-resistant component) that is one of embodiments will be described hereunder. A method for manufacturing a plasma-resistant component in which a deposited oxide film is formed of fine particles in an embodiment comprises the step of: supplying a slurry comprising particles of an oxide such as yttrium oxide into a high temperature plasma jet or a high temperature gas; heating the particles of an oxide such as yttrium oxide to a temperature less than the temperatures of the boiling point and the sublimation point; and spraying the particles onto a substrate at a spray speed of 400 to 1000 m/s. Preferably, a heating operation at a temperature equal to or more than the melting point temperature of the oxide and less than the boiling point and sublimation point temperatures is performed, and the spray speed is 500 to 1000 m/s.
The average particle size of the particles of an oxide such as yttrium oxide is preferably 0.05 to 3 μm, more preferably 0.05 to 1 μm. The slurry comprising the particles of an oxide such as yttrium oxide is preferably supplied to the center of a chamber at which a high temperature plasma jet or a high temperature gas is generated.
A film deposition apparatus for depositing fine particles comprises: a supply port for supplying a high temperature plasma jet or a high temperature gas; and a plasma torch or a high temperature gas generation chamber connected to the supply port. A slurry supply port is provided in a high temperature plasma jet or high temperature gas generation chamber, and a slurry of particles of an oxide such as yttrium oxide supplied from the slurry supply port is sprayed onto a substrate from the high temperature plasma jet or high temperature gas generation chamber via a nozzle and formed into a film. For the high temperature gas, a combustion flame of oxygen, acetylene, ethanol, kerosene, or the like may be used.
A method for manufacturing a plasma etching apparatus component comprises: the step of supplying a raw material slurry comprising an oxide raw material powder to a central portion of a high temperature plasma jet or a high temperature gas (oxide raw material powder supplying step); and the step of heating the oxide raw material powder in the high temperature plasma jet or the high temperature gas to a temperature less than the boiling point and sublimation point temperatures, and spraying the oxide raw material powder onto a surface of a substrate at a spray speed of 400 to 1000 m/s (oxide raw material powder spraying step).
When the concentration of the above slurry is in the range of 30 to 80% by volume, an advantage is that the raw material slurry has moderate fluidity and is smoothly supplied to the slurry supply port, and thus the amount of the raw material slurry supplied to the high temperature gas is stable, and therefore the film thickness and composition of the deposited oxide film become uniform.
<Supply of Raw Material Slurry to High Temperature Plasma Jet or High Temperature Gas>
As described above, the slurry supply port of a film deposition apparatus is usually provided so as to supply a raw material slurry to the central portion of a high temperature plasma jet or a high temperature gas. The spray speed of the high temperature plasma jet or the high temperature gas is high.
In the present invention, it is preferred that an oxide raw material powder in a raw material slurry is supplied to the central portion of a high temperature plasma jet or a high temperature gas because the spray speed of the oxide raw material powder in the high temperature plasma jet or the high temperature gas is stable, and variations in spray speed are less likely to occur, and at the same time the temperature of the high temperature plasma jet or the high temperature gas becomes constant, and it is easy to control the structure of the deposited oxide film.
In this connection, an oxide raw material powder in a raw material slurry being supplied to the central portion of a high temperature plasma jet or a high temperature gas flow means that an oxide raw material powder in a raw material slurry is supplied from the side to the central portion of a high temperature plasma jet or a high temperature gas flow. The central portion of a high temperature plasma jet or a high temperature gas means the central portion in a cross section perpendicular to the spray direction of a high temperature plasma jet or a high temperature gas.
On the other hand, when the oxide raw material powder in the raw material slurry is not supplied to the central portion of the high temperature plasma jet or the high temperature gas flow and is only supplied to the side of the high temperature plasma jet or the high temperature gas flow and the exterior of the high temperature plasma jet or the high temperature gas flow, the spray speed of the oxide raw material powder in the high temperature plasma jet or the high temperature gas is not stable, and variations in spray speed are likely to occur, and at the same time variations in the temperature of the high temperature plasma jet or the high temperature gas flow are large, and it is difficult to control the structure of the deposited oxide film.
Examples of the method for allowing the raw material slurry to be supplied to the central portion of the high temperature plasma jet or the high temperature gas flow include the position adjustment of the raw material slurry supply port and a method of adjusting the amount and speed of the raw material slurry supplied to the high temperature plasma jet or the high temperature gas.
The high temperature plasma jet or the high temperature gas and the oxide raw material powder prepared in the above step are sprayed toward a substrate from the spray nozzle of the film deposition apparatus. In the spray nozzle, the spray states of the high temperature plasma jet or the high temperature gas and the oxide raw material powder are controlled. Examples of the controlled spray states include the spray speed of the oxide raw material powder.
The spray nozzle of a film deposition apparatus is usually provided so as to spray a high temperature plasma jet or a high temperature gas and an oxide raw material powder in the lateral direction. A substrate is usually disposed so that a surface of the substrate is positioned on the extension line of the lateral spray nozzle of a film deposition apparatus.
When a deposited oxide film is formed from fine particles, the spray speed of oxide particles is preferably in the range of 400 m/s or more and 1000 m/s or less. When the spray speed is as slow as less than 400 m/s, the deposition of the particles in collision is insufficient, and a film having high film density may not be obtained. On the other hand, when the spray speed is more than 1000 m/s, the collision force is too strong, and the blasting effect of the oxide particles occurs, and the target deposited oxide film is less likely to be obtained.
The oxide particle slurry is preferably a slurry containing oxide particles having an average particle size of 0.05 to 3 μm as a raw material powder. The solvent for slurrying is preferably a solvent that volatilizes relatively easily such as methyl alcohol or ethyl alcohol.
The oxide particles are preferably sufficiently ground into a state in which no coarse particles are present and then mixed with the solvent. For example, when coarse particles having an average particle size of more than 3 μm are present, a uniform deposited film is less likely to be obtained. The content of the oxide particles in the slurry is preferably in the range of 30 to 80 vol. %. A slurry having moderate fluidity is more smoothly supplied to the supply port, and the amount of the slurry supplied becomes stable, and therefore a uniform deposited film can be obtained. A more preferred content is 50 to 80 vol %.
The plasma apparatus component as described above can be applied to various plasma apparatuses. For example, the micromachining of various thin films such as an insulating film, an electrode film, and a wiring film formed on a Si wafer or a substrate can be carried out using an RIE (Reactive Ion Etching) apparatus in which a halogen gas is turned into a plasma by a high frequency voltage applied between electrodes or the interaction between a microwave electric field and a magnetic field, and the produced ions and radicals are used for processing.
The plasma apparatus component that is one of embodiments can be applied to any place to be exposed to a plasma. Therefore, the plasma apparatus component can be applied not only to wafer disposition members such as electrostatic chucks but to all components to be exposed to a plasma such as inner wall portions.
The substrate on which the deposited oxide film is to be formed is not limited to quartz, and the deposited oxide film may be provided on a metal member or a ceramic substrate. The plasma apparatus component can be applied particularly to deposition shields, insulator rings, upper electrodes, baffle plates, focus rings, shield rings, bellows covers, and the like to be exposed to a plasma, among components used in plasma apparatuses but is not limited to the field of semiconductor manufacturing apparatuses and can also be applied to components of plasma apparatuses for liquid crystal devices and the like.
According to the present invention, the plasma resistance of a plasma apparatus component is improved significantly, which allows particle decrease and longer life of component use. Therefore, with a plasma apparatus using such a plasma-resistant component, a decrease in particles during plasma treatment and a decrease in the number of component replacements are possible.
In an RIE apparatus using a high density plasma, an insulating member may be used in order to maintain insulating properties from a high frequency voltage applied for plasma production.
For a protective film for an insulating member to be exposed to a plasma like an upper electrode used in plasma apparatus or the like, a three-layered coating obtained by forming an alumite film having high insulating properties, then forming a general thermally sprayed oxide film, and forming a deposited film of oxide fine particles on the thermally sprayed oxide film by a high speed fine particle deposition method is effective.
For the insulating properties, other than an alumite an aluminum oxide film may be formed by fine particle deposition. In this case, for the insulating properties, the adjustment of the thickness of the aluminum oxide film and the formation of a high density film are important. Particularly when an aluminum oxide film having an α structure is densely formed, a further effect is exerted, and therefore conditions equivalent to those of the formation of an yttrium oxide film are preferably set.
For a protective film for an insulating member to be exposed to a plasma like an insulator ring, a two-layered coating obtained by depositing an aluminum oxide film (alumite) having high insulating properties, and then forming a deposited yttrium oxide film on the aluminum oxide film is effective.
For the insulating properties, the adjustment of the thickness of the aluminum oxide film and the formation of a high density film are important. Particularly when an aluminum oxide film having an α structure is densely formed, a further effect is exerted, and therefore conditions equivalent to those of the formation of an yttrium oxide film are preferably set.
The undercoat layer is formed as an yttrium oxide film, but other oxides or mixtures thereof may be used, and the material is preferably selected according to the required properties.
In the case of a two-or-more-layered structure having a deposited yttrium oxide film at the outermost surface and an undercoat layer, the upper limit of the total film thickness is preferably 500 μm or less.
The undercoat layer is an aluminum oxide film, but other oxides or mixtures thereof may be used, and the material is preferably selected according to the required properties. In the case of a two-layered structure of an aluminum oxide film and an undercoat layer, the upper limit of the film thickness is preferably 500 μm or less.
According to the present invention, the generation of particles due to the peeling of adhering materials deposited on a plasma apparatus component can be suppressed, and the numbers of apparatus cleanings and component replacements can be significantly decreased.
The decrease in the amount of particles generated contributes greatly to defects during etching processing and defects in films during the formation of various thin films in semiconductor manufacturing, and further the improvement of the yield of an element or a component using it.
The decreases in the numbers of apparatus cleanings and component replacements, and the extension of the use life of a component contribute greatly to the improvement of productivity and the reduction of running cost.
One of embodiments of the present invention will be described in detail below with reference to the following Examples.
The conditions of the formation of yttrium oxide films formed with oxide fine particles shown in Table 1 (Examples 1 to 7) and a conventional thermal spraying method (Comparative Example 1) are shown. When thermal spraying was performed, an yttrium oxide film was formed by plasma spraying treatment, and then, a deposited yttrium oxide film was formed on a surface of an aluminum substrate (100 mm×200 mm) under conditions shown in Table 1 with fine particles emitted using a plasma type film deposition apparatus to provide a plasma apparatus component (plasma-resistant component).
The solvents of the yttrium oxide particle slurries were each ethyl alcohol. For each of the raw material powders used, high purity oxide particles having a purity of 99.99% or more were used. Further, for the yttrium oxide (Y2O3) particles as the raw material powders, yttrium oxide particles of cubic crystals free of coarse particles of more than 3 μm due to sufficient grinding and sieving were used. In Comparative Example 1, a thermally sprayed yttrium oxide film was formed by a plasma spraying method.
Film density for the respective Examples 1 to 7 and the Comparative Example 1 of the yttrium oxide films formed under the above conditions are shown in Table 1.
The film density was obtained from the proportion of pores in an enlarged photograph (magnification of 500×) taken so that the total unit area of a film cross section was 200 μm×200 μm.
As is clear from the results shown in Table 1, the deposited yttrium oxide films of the plasma-resistant components according to the present Examples each have high film density.
Although not shown in Table 1, the surface roughness Ra of each of the deposited films of the plasma-resistant components according to Examples 1 to 7 was 3 μm or less. In Comparative Example 1, the surface roughness Ra of the thermally sprayed yttrium oxide film was 6.3 μm.
Next, the evaluation results of the plasma resistance of the plasma-resistant components according to the above Examples 1 to 7 and Comparative Example 1 are shown in Table 2. In other words, each of the plasma-resistant components in which the deposited yttrium oxide films were formed and the plasma-resistant component in which the thermally sprayed yttrium oxide film was formed shown in the Examples and the Comparative Example in Table 1 was disposed in a plasma etching treatment apparatus (RIE) and exposed to a plasma produced in a mixed gas flow of CF4 (flow rate: 80 sccm)+O2 (20 sccm)+Ar (100 sccm). The pressure in the RIE chamber was set at 20 mTorr, the RF output was set at 100 W, and the plasma etching treatment apparatus was continuously operated for 12 hours (“operation cycle comprising: a discharge for 20 minute; and a cooling for 10 minute” was repeated for 24 cycles). Then, the amount of particles removed from the yttrium oxide film was investigated by peeling evaluation by a Scotch tape method (Scotch tape is a registered trademark of 3M Company).
Specifically, a Scotch tape was affixed to the deposited film or the thermally sprayed film comprising yttrium oxide, and then the tape was peeled and observed by an SEM (Scanning Electron Microscope), and the area in which removed particles present in a field of view 80 μm long×60 μm wide adhered was measured.
In addition, the weight of the component in which the yttrium oxide film was formed was measured by a precision balance before and after the above exposure test was performed, and the amount of weight decrease of the component before and after the test was measured. The measurement results are shown in the following Table 2.
As is clear from the results shown in the above Table 2, in the components in which the deposited oxide films comprising the fine particles are formed on the substrates (Examples 1 to 7), compared with the component in which the thermally sprayed film is formed by the conventional thermal spraying method (Comparative Example 1), the amount of weight decrease is significantly decreased, and the amount of particles removed from the deposited yttrium oxide film is also one or more orders of magnitude smaller. From these results, it was confirmed that RIE apparatus components in which protective films were formed of the fine particles according to the present Examples had strong resistance to plasma attack and radical attack. Being resistant to plasma attack and radical attack means that the generation of particles can be effectively suppressed in use in an RIE apparatus.
In the above Examples, examples in which a conventional thermally sprayed yttrium oxide film is formed on a surface of each substrate, and then a deposited yttrium oxide film of fine particles is formed, or examples in which a deposited yttrium oxide film of fine particles is formed directly on a substrate are shown.
However, by forming at least one insulating film such as aluminum oxide between a surface of the substrate and the deposited yttrium oxide film of a component and forming the deposited yttrium oxide film of fine particles on the outermost surface thereof, the effect of increasing insulating properties as a component is also exerted.
As described above, according to the RIE (plasma etching) apparatus component according to the embodiment of the present invention, the corrosion of the deposited film caused by the radicals of a corrosive gas is suppressed, and the stability of each component and the film itself can be increased, and therefore the generation of particles from the component and the deposited film can be suppressed. Further, the component is used with longer life, and reaction products generated by corrosion decrease, and therefore the number of replacements of the components and the number of cleanings of the component can be reduced.
After the use of the component, by subjecting the thermally sprayed yttrium oxide film formed by the plasma spraying method to blasting treatment to remove adhering products on the thermally sprayed surface, and depositing a deposited yttrium oxide film of fine particles thereon, the regeneration treatment of the component can be smoothly carried out, and at the same time damage to the component is reduced, and the recycle of the component becomes possible, and the reduction of component cost is implemented.
In the above embodiment, an RIE (plasma etching) apparatus is illustrated as a plasma apparatus, but the present invention is not limited to components used in these, and in addition, the component having the deposited oxide film in the above embodiment can be also applied to all apparatuses that generate plasmas for treatment such as plasma CVD (Chemical Vapor Deposition) apparatuses.
As described above, several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be carried out in other various forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and spirit of the invention and included in the present invention described in the claims and an equivalent scope thereof.
REFERENCE SIGNS LIST
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- 1 . . . plasma apparatus component (plasma-resistant component), 2 . . . deposited yttrium oxide film, 3 . . . substrate, 4 . . . substrate, 5 . . . molten flat particle (flat particle flatten by melting), 6 . . . microcrack, 7 . . . pore (void), 8 . . . polycrystalline particle, 9 . . . grain boundary, 10 . . . microparticle, 11 . . . plasma arc generation chamber or high temperature gas generation chamber, 12 . . . spray nozzle, 13 . . . working gas supply port, 14 . . . fuel or oxygen gas supply port, 15 . . . raw material slurry supply port
Claims
1. A plasma-resistant component for use in a plasma apparatus, wherein an oxide film is formed on at least part of a surface of a substrate of the component, the oxide film is a deposited oxide film formed as an aggregate of polycrystalline particles, the polycrystalline particles being formed by sinter-bonding of microparticles having an average particle size of 0.05 to 3 μm, and the deposited oxide film has a film thickness of 10 μm or more and 200 μm or less and a film density of 90% or more.
2. The plasma-resistant component according to claim 1, wherein the polycrystalline particles forming the deposited oxide film are polycrystalline particles having an average particle size of 0.5 to 10 μm when a cross section of the deposited oxide film perpendicular to a substrate plane is observed microscopically.
3. The plasma-resistant component according to claim 1, wherein no microcracks are present in the polycrystalline particles of the deposited oxide film.
4. The plasma-resistant component according to claim 1, wherein an area percentage of microparticles having a particle size of 3 μm or less present in the deposited oxide film is 10% or less when a cross section of the deposited oxide film perpendicular to the substrate plane is observed microscopically.
5. The plasma-resistant component according to claim 1, wherein an area percentage of particles flattened by melting present in the deposited oxide film is 10% or less when a cross section of the deposited oxide film perpendicular to the substrate plane is observed microscopically.
6. The plasma-resistant component according to claim 1, wherein the oxide film is formed of a two-layered structure of a thermally sprayed oxide film as an undercoat layer formed on the substrate and a deposited oxide film formed on a surface of the undercoat layer, a total film thickness of the thermally sprayed oxide film and the deposited oxide film is 20 μm or more and 300 μm or less, and a film thickness of the deposited oxide film is 10 μm or more and 200 μm or less.
7. The plasma-resistant component according to claim 1, wherein the oxide film is formed of a three-layered structure of an oxide film formed by oxidation treatment of the surface of the substrate, a thermally sprayed oxide film as an undercoat layer formed on a surface of the oxide film, and a deposited oxide film formed on an upper surface of the thermally sprayed oxide film, a total film thickness of the oxide film, the thermally sprayed oxide film as the undercoat layer, and the deposited oxide film is 20 μm or more and 300 μm or less, and a film thickness of the deposited oxide film is 10 μm or more and 200 μm or less.
8. The plasma-resistant component according to claim 1, wherein raw material microparticles used for formation of the deposited oxide film are oxide particles having a purity of 99.9% or more.
9. The plasma-resistant component according to claim 1, wherein a surface roughness Ra of the deposited oxide film is 3 μm or less.
10. The plasma-resistant component according to claim 1, wherein the deposited oxide film comprises Y2O3.
11. The plasma-resistant component according to claim 1, wherein the deposited oxide film comprises Al2O3.
12. A method for manufacturing the plasma-resistant component according to claim 1, comprising steps of: supplying a slurry comprising oxide particles to a central portion of a high temperature plasma jet or a high temperature gas flow; heating the oxide particles to a temperature less than both a boiling point and a sublimation point of an oxide and spraying the oxide particles onto a substrate at a spray speed of 400 to 1000 m/s; and forming a deposited oxide film on the substrate.
13. A film layering apparatus used for manufacture of the plasma-resistant component according to claim 1, comprising a substrate and a deposited oxide film covering a surface of the substrate, comprising:
- a generation chamber for generating a high temperature plasma jet or a high temperature gas by a plasma arc;
- a raw material slurry supply port for supplying a raw material slurry comprising an oxide raw material powder to a central portion of the high temperature plasma jet or the high temperature gas;
- a fuel supply port for supplying a fuel or an oxygen gas to the generation chamber;
- a gas supply port for supplying a working gas to the generation chamber; and
- a spray nozzle for gasifying the raw material slurry with the working gas and the fuel or the oxygen gas, heating an oxide raw material in a gas to a temperature less than both a boiling point and a sublimation point of an oxide, and controlling the oxide raw material in a state in which it is sprayed onto a surface of a substrate at a spray speed of 400 to 1000 m/s.
14. The film layering apparatus according to claim 13, wherein a spray distance between a tip portion of the spray nozzle for spraying the oxide raw material onto a surface of a substrate and the surface of the substrate is 100 to 400 mm.
15. The film layering apparatus according to claim 13, wherein a content of the oxide raw material powder in the raw material slurry is 30 to 80% by volume.
Type: Application
Filed: Mar 20, 2015
Publication Date: Jan 26, 2017
Applicants: KABUSHIKI KAISHA TOSHIBA (Tokyo), TOSHIBA MATERIALS CO., LTD. (Yokohama-Shi, Kanagawa-Ken)
Inventors: Michio SATO (Yokohama, Kanagawa), Takashi HINO (Yokohama, Kanagawa), Masashi NAKATANI (Yokkaichi, Mie), Takashi NAKAMURA (Yokohama, Kanagawa)
Application Number: 15/124,477
