Film deposition material suitable for plasma etching apparatus member

Abstract

To provide: an Er2O3-Al2O3 composite oxide based film deposition material suitable for a plasma etching apparatus member and high in plasma resistance; a film deposition method; and a coating, especially, a thermal spraying coating.SOLUTION: (a) a film deposition material includes two or more kinds of Er2O3-Al2O3 composite oxides, or (b) a film deposition material includes one or more kinds of Er2O3-Al2O3 composite oxides and Er2O3. Each of the conversion molar amount of the Er2O3 to the total molar amount of the two or more kinds of Er2O3-Al2O3 composite oxides in the (a) and the conversion molar amount of the Er2O3 to the total molar amount of one or more kinds of Er2O3-Al2O3 composite oxides and the Er2O3 in the (b) is 38-75 mol%.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a high plasma-resistant Er2O3-Al2O3 composite oxide-based film-forming material, a film-forming method, and a film, particularly a sprayed film, which are suitable for members for plasma etching apparatuses used in high-integration semiconductor manufacturing.

Background Art

[0002] Materials constituting a chamber for performing plasma etching in semiconductor manufacturing are metal materials such as aluminum alloys, and their resistance to exposure to halogen-based gas plasmas is not high. Therefore, the chamber is coated with a plasma-resistant material to suppress the chamber from being eroded by plasma and generating particles.

[0003] In Patent Document 1, as a plasma-resistant material coated on a chamber, a plasma treatment container internal member excellent in plasma erosion resistance is proposed by forming a Y2O3 sprayed film on the surface of a substrate such as a metal, ceramics, or carbon material inside the plasma treatment container.

[0004] Patent Document 2 proposes a substrate support assembly excellent in plasma corrosion resistance by coating a sprayed film of a Y2O3-Al2O3 composite oxide such as Y3Al5O on a ceramics body of a semiconductor processing apparatus. 12

[0005] Patent Document 3 proposes coating a protective layer containing a first ceramic selected from the group consisting of ceramics compounds containing Y3Al5O, Y4Al2O9, Er2O3, Gd2O3, Er3Al5O, Gd3Al5O, and a solid solution of Y4Al2O9 and Y2O3-ZrO2 on the surface of the apparatus body, under the title of a plasma corrosion-resistant rare earth oxide-based coating. 12 12 12

[0006] Patent Document 4 proposes a chamber component for an etching reactor, which is provided with a protective layer of ceramics containing Y3Al5O 12 , Y4Al2O9, Er2O3, Gd2O3, Er3Al5O 12 , Gd3Al5O 12 , YF3, Nd2O3, Er4Al2O3, ErAlO3, Gd4Al2O3, GdAlO3, Nd3Al5O 12 , Nd4Al2O3, NdAlO3, or a solid solution of Al2O9 and Y2O3-ZrO on the surface of a ceramics body.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0008] In recent years, semiconductors used in advanced technology fields have become increasingly highly integrated, and the line width of circuits formed on chips is required to be 20 nm or less. For this reason, minute particles with a size of several tens of nm, which were not a problem in plasma etching before, have also become a problem, and the required level of plasma resistance has become stricter than before.

[0009] The Y2O3 sprayed film of Patent Document 1 contains fluorine on the surface layer of the film when exposed to fluorine-based plasma. A passivation layer or an acid fluoride layer is formed, but cracks are likely to occur in these layers. When cracks occur, there is a possibility that plasma consumption may selectively progress from the cracks, or particles may be generated when cracks occur.

[0010] In the thermal spray coating of the Y2O3 - Al2O3 composite oxide of Patent Document 2, when the ratio of Y2O3 / Al2O3 is appropriate, an acid fluoride layer without cracks may be formed when exposed to fluorine - based plasma, but its consumption rate is higher than that of Y2O3.

[0011] In Patent Documents 3 and 4, rare - earth - containing composite oxides other than Y2O3 - Al2O3 composite oxides are exemplified, and some of them have a lower consumption rate than the Y2O3 - Al2O3 composite oxide. However, these composite oxides have a complex crystal structure, low toughness and thermal shock resistance, and cracks starting from crystal interfaces are likely to occur due to mechanical or thermal shock. Since the integrity of the crystal interfaces where these cracks occur is low, the cracks may spread widely through the crystal interfaces, and there is a risk of generating macroscopic cracks.

[0012] The present invention has been made under such circumstances, and it is an object of the present invention to provide a film - forming material having more excellent plasma - resistant properties, a film - forming method using the film - forming material, and a coating, particularly a thermal spray coating, which are suitable as members for plasma etching apparatuses such as semiconductor manufacturing processes or their protective films and can be applied to even more stringent standards in recent years.

Means for Solving the Problems

[0013] In order to achieve the above - mentioned object, the present invention has conducted research on a plasma - resistant film - forming material containing an Er2O3 - Al2O3 composite oxide. As a result, even when an acid fluoride layer is formed on the film surface when exposed to fluorine - based plasma during plasma etching, in addition to having the property that cracks are unlikely to occur in the acid fluoride layer, a film - forming material capable of suppressing the occurrence of macroscopic cracks inside the film has been found.

[0014] The present invention is based on such novel findings and has the following aspects. (1) (a) A film-forming material containing two or more kinds of Er2O3-Al2O3 composite oxides, or (b) a film-forming material containing one or more kinds of Er2O3-Al2O3 composite oxides and Er2O3, wherein, in (a), the molar amount of Er2O3 in terms of Er2O3 relative to the total molar amount of the two or more kinds of Er2O3-Al2O3 composite oxides, or in (b), the molar amount of Er2O3 in terms of Er2O3 relative to the total molar amount of the one or more kinds of Er2O3-Al2O3 composite oxides and Er2O3 is both 38 to 75 mol%, and the film-forming material is characterized in that. (2) A film-forming method by thermal spraying using the film-forming material described in (1) above. (3) A method for manufacturing a member for a plasma etching apparatus, in which a thermal spray coating is formed on a substrate by the film-forming method described in (2) above.

[0015] (4) (a) A thermal spray film containing two or more kinds of Er2O3-Al2O3 composite oxides, or (b) a thermal spray film containing one or more kinds of Er2O3-Al2O3 composite oxides and Er2O3, wherein, in (a), the molar amount of Er2O3 in terms of Er2O3 relative to the total molar amount of the two or more kinds of Er2O3-Al2O3 composite oxides, or in (b), the molar amount of Er2O3 in terms of Er2O3 relative to the total molar amount of the one or more kinds of Er2O3-Al2O3 composite oxides and Er2O3 is both 38 to 75 mol%, and the thermal spray film is characterized in that. (5) A member for a plasma etching apparatus provided with the thermal spray film described in (4) above.

Advantages of the Invention

[0016] According to the present invention, compared with the coating of Y2O 3-Al2O3 composite oxide, which has been considered to have excellent properties and has been put into practical use so far, the plasma resistance is further excellent, and even when the coating surface is exposed to fluorine-based plasma during plasma etching and an acid fluoride layer is formed on the coating surface, not only is it difficult for cracks to occur in this acid fluoride layer, but it is also possible to suppress the occurrence of macroscopic cracks inside the coating. The above effects achieved by the present invention are explained by the following mechanism. Unlike yttrium (Y), erbium (Er) is a heavy rare earth element and is inherently difficult to be physically sputtered when exposed to plasma. Therefore, the film of Er2O3-Al2O3 composite oxide has better plasma resistance than the film of Y2O3-Al2O3 composite oxide which has excellent properties and has been put into practical use so far.

[0017] In addition, when the Er2O3-Al2O3 composite oxide is exposed to a fluorine-based plasma, fluorides and oxyfluorides are generated on the surface. At this time, stable oxyfluorides (Er-O-F-based compounds) are easily generated in the Er2O3 main part, but no oxyfluorides are generated in the Al2O3 main part, and only fluorides (Al-F binary fluorides) are generated. Compared with the reaction of generating oxyfluorides from Er2O3, the reaction of generating fluorides from Al2O3 is less likely to occur. Moreover, even if Al-F binary fluorides are generated, their vaporization temperature is low and they are easily volatilized after generation. For this reason, when the exposure to the fluorine-based plasma continues, the Er2O3-Al2O3 composite oxide grows concentrically, so most of the surface will be covered only with Er-O-F-based compounds with high plasma resistance. However, there is a large difference in the thermal expansion coefficient between the Er-O-F-based compound and the Er2O3-Al2O3 composite oxide. Therefore, when a wide and continuous reaction layer of oxyfluoride is formed, cracks are likely to occur. However, since the Al2O3 main part exists in the Er2O3-Al2O3 composite oxide, there is a region where the Al-F binary fluorides volatilize after generation, and the Er-O-F-based compound reaction layer does not continue widely. As a result, when the surface of the Er2O3-Al2O3 composite oxide film is exposed to a fluorine-based plasma, an oxyfluoride layer is formed, but there are discontinuous surfaces between the grown oxyfluoride crystals, which serve as stress relaxation layers and make it difficult for cracks to occur.

[0018] In addition, in the present invention, a film containing two or more types of Er2O3-Al2O3 composite oxides, or a film containing one or more types of Er2O3-Al2O3 composite oxides and Er2O3, during grain growth at the time of film formation, compounds having different compositions collide with each other to produce a pinning effect, and it becomes possible to suppress the generation of cracks in the film. In particular, Er3Al5O 12 Since the combination of ErAlO3 and the combination of ErAlO3 and Er4Al2O3 are eutectic relationships, respectively, the interfaces of both generated by sintering or melting and solidification have high consistency. For this reason, even when mechanical or thermal shock is applied, cracks starting from the interface are less likely to occur. Further, even if cracks occur in the crystal grains or pores of the film, the propagation of the cracks stops at the interfaces of different crystal phases and does not spread widely. As a result, it becomes possible to suppress the generation of macroscopic cracks inside the film.

Brief Description of the Drawings

[0019]

Figure 1

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Figure 7

Modes for Carrying Out the Invention

[0020] Preferred modes for carrying out the present invention will be described below. In addition, in this specification, when describing a numerical range, if the units of the upper and lower limits are the same, the description of the unit of the lower limit may be omitted. Also, in this specification, unless otherwise specified, the average particle diameter (median diameter) means the particle diameter (D50) at 50% of the integrated value based on volume in the particle size distribution determined by the laser diffraction / scattering method.

[0021] <Film-forming material> The film-forming material of the present invention is (a) a film-forming material containing two or more types of Er2O3-Al2O3 composite oxides, or (b) a film-forming material containing one or more types of Er2O3-Al2O3 composite oxides and Er2O3. As the Er2O3-Al2O3 composite oxide used in the film-forming material of the present invention, Er3Al5O 12 (EAG), ErAlO3 (EAP), or Er4Al2O9 (EAM) is preferable, but it is not limited thereto as long as it is a composite oxide formed from Er2O3 and Al2O3.

[0022] In any of the film-forming materials of the present invention, (a) a film-forming material containing two or more types of Er2O3-Al2O3 composite oxides, or (b) a film-forming material containing one or more types of Er2O3-Al2O3 composite oxides and Er2O3, the converted molar amount of Er2O3 with respect to the total molar amount of the two or more types of Er2O3-Al2O3 composite oxides contained in the film-forming material, or the converted molar amount of Er2O3 with respect to the total molar amount of the one or more types of Er2O3-Al2O3 composite oxides and Er2O3 contained in the film-forming material is 38 to 75 mol%, preferably 40 to 70 mol%, more preferably 48 to 67 mol%, and still more preferably 55 to 66 mol%. When the converted molar amount of the above Er2O3 is less than 38 mol%, Al2O3 is exposed in the reaction layer generated by exposure to CF-based plasma and the consumption rate increases. Also, when the converted molar amount of Er2O3 exceeds 75 mol%, the continuity of the acid fluoride reaction layer increases and cracks are likely to occur.

[0023] In the present invention, the equivalent molar amount of the above Er2O3 is defined as follows. Equivalent molar amount of Er2O3 (%) = (total amount of the molar amount present as Er2O3 in the film-forming material (a) or (b) and the equivalent molar amount of Er2O3 present in the Er2O3-Al2O3 composite oxide / total molar amount of the Er2O3-Al2O3 composite oxide and Er2O3) × 100 Such an equivalent molar amount of Er2O3 can be easily determined by the usage amounts of Er2O3 and Al2O3 as raw materials, namely, the charged amounts of Er2O3 and Al2O3, in the case of manufacturing each of the film-forming materials (a) and (b). Alternatively, the above equivalent molar amount of Er2O3 can also be determined by converting the value of Er analyzed by fluorescent X-ray analysis or the like of each manufactured film-forming material into an oxide.

[0024] When the film-forming material of the present invention is the film-forming material (a) containing two or more kinds of Er2O3-Al2O3 composite oxides, the combination of the Er2O3-Al2O3 composite oxides is Er3Al5O 12 and the combination of ErAlO3, the combination of ErAlO3 and Er4Al2O9, or Er3Al5O 12 , the combination of ErAlO3 and Er4Al2O9 is preferable. Among them, the combination of ErAlO3 and Er4Al2O9 is preferable, and the ratio of Er4Al2O9 is preferably 40 mol% or more and less than 80 mol%. The consumption rate of Er4Al2O9 with respect to fluorine-based plasma is lower than the consumption rate of ErAlO3, and from the viewpoint of fully enjoying the effect, the ratio of Er4Al2O9 is preferably 40 mol% or more. Also, from the viewpoint of obtaining the effect of the two-phase structure, the ratio of ErAlO3 is preferably 20% or more, and therefore the ratio of Er4Al2O9 is preferably less than 80 mol%.

[0025] Further, when the film-forming material of the present invention is the film-forming material (b) containing one or more kinds of Er2O3-Al2O3 composite oxides and Er2O3, as the one or more kinds of Er2O3-Al2O3 composite oxides, Er4Al2O9 alone, Er3Al5O12 and combinations of ErAlO3, combinations of ErAlO3 and Er4Al2O9, Er3Al5O 12 is preferably a combination of, ErAlO3, and Er4Al2O9.

[0026] <Method for manufacturing a film-forming material> A typical preferred method for manufacturing the film-forming material of the present invention will be described below. First, when obtaining the Er2O3-Al2O3 composite oxide contained in the film-forming material of the present invention, Er2O3 powder and Al2O3 powder are prepared, pulverized and mixed using an apparatus such as a rotary ball mill, and heat-treated at a high temperature in the air or an inert atmosphere using an electric furnace or the like to produce an Er2O3-Al2O3 composite oxide.

[0027] The purity of each powder used when pulverizing and mixing Er2O3 powder and Al2O3 powder is preferably 99.5% by weight or more. Further, the average particle size (median diameter) of these powders subjected to the pulverizing and mixing step is preferably 4 μm or less.

[0028] The average particle size of the Al2O3 powder and Er2O3 powder after pulverizing and mixing is preferably 2 μm or less, but if it is too small, aggregation is likely to occur during mixing, so it is preferably 0.5 μm or more. By setting the average particle size of the Al2O3 powder and Er2O3 powder within the above range, the contact opportunity between the Er2O3 powder and the Al2O3 powder can be increased. In this way, by performing heat treatment in a state where the contact opportunity between the Er2O3 powder and the Al2O3 powder is large, the solid-phase reaction is promoted, and it becomes possible to react the Al2O3 powder with the Er2O3 powder in a short time.

[0029] The respective contents of the Er2O3 powder and the Al2O3 powder vary depending on the type of the Er2O3-Al2O3 composite oxide to be contained in the film-forming material. Er3Al5O 12When incorporated into the film-forming material, the content of Er2O3 powder is preferably 38 to 50 mol%, and the content of Al2O3 powder is preferably 50 to 62 mol%. When incorporating ErAlO3 into the film-forming material, the content of Er2O3 powder is preferably 38 to 66.7 mol%, and the content of Al2O3 powder is preferably 33.3 to 62 mol%. When incorporating Er4Al2O9 into the film-forming material, the content of Er2O3 is preferably 50 to 75 mol%, and the content of Al2O3 powder is preferably 25 to 50 mol%.

[0030] The heat treatment during sintering of the mixed powder of Er2O3 powder and Al2O3 powder varies depending on the mixing ratio of the Er2O3 powder. When the mixing ratio of the Er2O3 powder is 50 mol% or less, it is preferably carried out at 900 °C to 1400 °C, more preferably 1000 to 1300 °C. When the mixing ratio of the Er2O3 powder exceeds 50 mol%, it is preferably 1100 °C to 1600 °C, more preferably 1200 to 1500 °C. This enables the solid-phase reaction rate between the Er2O3 powder and the Al2O3 powder to be made sufficiently fast and also enables the grain size adjustment of the sintered body after heat treatment.

[0031] If the heat treatment is carried out at a temperature lower than the above range, the homogenization of the structure is not sufficient, and the solid-phase reaction rate is slow, resulting in a very long production time. On the other hand, if the treatment is carried out at a temperature higher than the above range, the sintering between Er2O3 particles becomes active, and as consolidation progresses, subsequent grain size adjustment and the like become difficult. The heat treatment time is preferably 3 to 12 hours, more preferably 5 to 8 hours.

[0032] Next, the synthetic powder sintered together by heat treatment is loosened and added to a solvent or the like to form a slurry, and then granulated into preferably spherical particles having an average particle size of preferably 15 to 40 μm by a spray drying method or the like. These granulated particles are heated in an oxidation atmosphere using an electric furnace or the like to preferably 900 to 1400 °C, more preferably 1000 to 1300 °C, in order to remove the organic binder and improve the fracture strength of the spherical particles, and then used as a film-forming material.

[0033] Note that the method for manufacturing the film-forming material of the present invention is not limited to the above method. Other methods include a fine particle dispersion sol using a metal oxide as a dispersoid and a method using a metal salt. For example, a commercially available Er2O3 powder, Al2O3 sol, and a solvent are mixed so that the mixing ratio of Er2O3 and Al2O3 becomes the above-described preferred predetermined ratio, and this mixed solution is used as a raw material for spray drying granulation, whereby spherical particles composed of primary particles of Er2O3 fine particles and Al2O3 fine particles are obtained. By heat-treating these spherical particles in an oxidizing atmosphere at a temperature preferably of 1000 to 1500 ° C, it is possible to simultaneously realize a reaction treatment for integration and an improvement in the fracture strength of the spherical particles, and the spherical particles after heat treatment are used as a film-forming material.

[0034] Also, the method for manufacturing the film-forming material of the present invention can also be carried out by an electrofusion and pulverization method. For example, an ingot is obtained by melting and casting a mixture of Er2O3 powder and Al2O3 powder mixed in the above-described predetermined mixing ratio by an electrofusion method, preferably at a temperature of 3000 to 4000 ° C. This ingot is sequentially pulverized using a device such as a jaw crusher or a ball mill and adjusted to a suitable particle size range to be used as a film-forming material.

[0035] Furthermore, in the above-described manufacturing method of the film-forming material of the present invention, Er2O3 and Al2O3 are used as starting materials, but Y2O3-Al2O3 composite oxides such as Er3Al5O 12 (EAG), ErAlO3 (EAP), or Er4Al2O9 (EAM) can also be used as starting materials. In this case, for example, these Y2O3-Al2O3 composite oxides and, if necessary, Er2O3 are used, and if necessary, a solvent is used to mix them so that the mixing ratio of these raw materials becomes the above-described preferred predetermined ratio, and this mixed solution is used as a raw material for spray drying granulation to obtain spherical particles. These spherical particles can be manufactured by heat-treating them in an oxidizing atmosphere at a temperature preferably of 1000 to 1500 ° C.

[0036] <Film-forming method> As a method for forming a film using the film-forming material of the present invention, known methods such as a spraying method and a physical vapor deposition method can be mentioned. Among them, the spraying method is preferable because it is difficult for the temperature of the base material to be film-formed to rise and a thick film that can withstand long-term use can be easily obtained. Examples of the spraying method in the present invention include an atmospheric pressure plasma spraying method and a reduced pressure plasma spraying method. Among them, the atmospheric pressure plasma spraying method is preferable. As the atmospheric pressure plasma spraying method suitable for the present invention, known ones can be used including apparatuses and conditions. For example, the following can be mentioned. Spraying apparatus: Plasma spraying gun (manufactured by Sulzer Metco, 9MB) Operating voltage: 65V Operating current: 700A Flow rate of primary gas (Ar): 60NL / min Flow rate of secondary gas (H2): 5NL / min Spraying distance: 140mm

[0037] Examples of the physical vapor deposition method suitable for the present invention include a sputtering method, an ion plating method, an arc ion plating method, an electron beam physical vapor deposition method, etc. Among them, the electron beam physical vapor deposition method is preferable. As the electron beam physical vapor deposition method suitable for the present invention, known ones can be used including apparatuses and conditions. For example, the following can be mentioned. Apparatus: Von Ardenne, Tuba150 Substrate temperature: 450°C Chamber pressure: 1.0Pa Operating voltage: 60kW

[0038] In the present invention, by using such a film-forming method, preferably a spraying method, and using the above film-forming material, the film of the present invention, preferably a sprayed film, can be obtained. Such a film retains the composition of the film-forming material used in the film-forming method and has characteristics suitable for members for plasma etching apparatuses.

[0039] <Method for manufacturing a member for a plasma etching apparatus> The film-forming material of the present invention is applied to members for plasma etching apparatuses used in semiconductor manufacturing, etc. The member for a plasma etching apparatus in the present invention is a member that can be exposed to plasma during a plasma process, and examples thereof include internal members of an etching chamber and an electrostatic chuck.

[0040] The plasma etching apparatus in the present invention has a cylindrical chamber, a plasma generation part such as an electrode, and members such as an electrostatic chuck for holding a wafer. The wafer held on the electrostatic chuck in the chamber is subjected to an etching process by the action of the plasma generated by the plasma generation part. At this time, the generated plasma acts not only on the wafer but also on the internal member of the chamber and the electrostatic chuck.

[0041] The member for a plasma etching apparatus in the present invention means a member that can be exposed to plasma such as the above-described internal member of the chamber and the electrostatic chuck. These members for plasma etching apparatuses are required to have high plasma resistance in order to suppress the generation of fine particles generated when the members are exposed to plasma. Therefore, by forming a protective film using the film-forming material of the present invention on the base material of the member for a plasma etching apparatus by a spraying method or a physical vapor deposition method, the member for a plasma etching apparatus can be provided with high plasma resistance.

Examples

[0042] Hereinafter, the present invention will be specifically described by way of examples. Note that the present invention is not construed as being limited to these examples.

[0043] (Examples 1 to 3 and Comparative Examples 1 to 5) The following raw material powders were prepared. Er2O3... manufactured by Shin-Etsu Chemical Co., Ltd., purity 99.9%, median diameter 0.95 μm Y2O3... manufactured by Shin-Etsu Chemical Co., Ltd., purity 99.9%, median diameter 0.97 μm Al2O3... manufactured by Sumitomo Chemical Co., Ltd., purity 99.99%, median diameter 0.58 μm

[0044] These powders were weighed so as to have the compounding ratios shown in Table 1 and Table 2, and wet-mixed using a planetary mill with a zirconia pot and balls, with pure water as a solvent, to obtain a slurry. The obtained slurry was dried by an evaporator to obtain a mixed powder. After filling these mixed powders into an alumina crucible, heat treatment was performed at a temperature of 1000°C to 1400°C for 24 hours in air using an electric furnace. The powder after heat treatment was crushed and used for the production of a sintered body as a film-forming material. In Comparative Examples 2 and 4, the above-prepared crude raw materials were directly used for the production of the sintered body.

[0045] The sintered body as a film-forming material was produced by the spark plasma sintering method. Each powder was filled into a carbon mold and sintered at a maximum heating temperature of 1350°C to 1600°C and a pressure of 80 MPa. After polishing the sintered body taken out from the carbon mold, heat treatment in air was performed at 1500°C for 3 hours using an electric furnace. When the open porosity was measured by the Archimedes method after the heat treatment, it was all 0.2% or less.

[0046] Each of the sintered bodies obtained above was mirror-polished, and qualitative analysis by X-ray diffraction measurement method (XRD, SmartLab manufactured by Rigaku Corporation) was performed to identify the precipitated crystal phases. The crystal phases detected by XRD were classified into main constituent phases and sub-constituent phases based on a calibration curve prepared in advance.

[0047] Here, the method for preparing the calibration curve is shown below. Er2O3 crude powder and Al2O3 crude powder were weighed in a stoichiometric ratio, mixed, and subjected to high-temperature heat treatment to synthesize powders of Er3Al5O 12 , ErAlO3, and Er4Al2O9. Each of the synthesized powders was subjected to XRD analysis to confirm that they were each single-phase. A plurality of types of mixed powders of Al2O3 powder and Er3Al5O 12 powder with different mixing ratios were prepared, and XRD measurement was performed on each mixed powder. A calibration curve for the constituent phases was created from the ratio of the peak heights of the chart obtained by XRD measurement and the mixing ratio. The same process was also carried out for each combination of Er3Al5O 12 powder and ErAlO3 powder, ErAlO3 powder and Er4Al2O9 powder, and Er4Al2O9 powder and Er2O3 powder to create calibration curves for each combination. Then, the abundance ratio (content ratio) of the crystal phases detected by XRD measurement of each sintered body was calculated based on the calibration curve.

[0048] When only two types of crystal phases were detected in the sintered body, the abundance ratio of each crystal phase in the sintered body was calculated by comparing the peak ratio of the two detected crystal phases with the peak ratio of the calibration curve of the same combination. When three or more types of crystal phases were detected in the sintered body, first, a reference crystal phase was determined. Subsequently, the peak ratios of the reference crystal phase and the other crystal phases were calculated respectively. Then, the peak ratios of each obtained combination were compared with the peak ratios of the calibration curves corresponding to each combination, and the abundance ratios of the other crystal phases with respect to the reference crystal phase were calculated respectively to obtain the abundance ratio of each crystal phase in the sintered body. The crystal phase with an abundance ratio of 25% or more in the sintered body was classified as the main constituent phase, and the crystal phase with an abundance ratio of less than 25% was classified as the sub-constituent phase. The results are shown in Tables 1 and 2.

[0049] Furthermore, each of these sintered bodies was mirror-polished and subjected to the following [Plasma Exposure Test] and [Reaction Test with Fluoride]. [Plasma Exposure Test] In the plasma exposure test, a test specimen was placed still on a 4-inch diameter Si wafer using a dry etching apparatus and exposed to plasma gas. The plasma gas was generated under the following conditions. Plasma gas composition and flow rate: CF4··50 sccm, O2···10 sccm, Ar···50 sccm RF output··800 W, bias··600 W

[0050] The erosion rate by plasma was measured by measuring the step difference between the exposed part and the non-exposed part, and was expressed as a relative value with the erosion rate of the simultaneously exposed Si wafer set to 100. The results of the erosion rates in the plasma exposure tests for the sintered compacts of Examples 1 to 3 and Comparative Examples 1 to 5 are shown in Table 1 below. As shown in Table 1, the erosion rates of the sintered compacts of Examples 1 to 3 were 9.8, 9.0, and 8.4, respectively, which were lower than 11.7 of Comparative Example 1 and 11 of Comparative Example 3, and were close to 8.4 of Comparative Example 2.

[0051]

Table 1

[0052] [Reaction Test with Fluoride] The test was conducted by heating the test piece while pressing it against the powder layer of the fluoride. The fluoride powder was spread in an alumina crucible, the mirror-polished surface of the sintered compact as the test piece was pressed, and a yttria-stabilized zirconia sintered compact was placed thereon and subjected to heat treatment. The heat treatment was performed using an electric furnace and held at 850 °C for 1 hour in an argon atmosphere.

[0053] In Examples 1 to 3 and Comparative Examples 1 and 4, ErF3 (purity: 99.9, median diameter: 0.18 μm) was used as the fluoride powder. On the other hand, in Comparative Examples 2 and 5, YF3 (purity: 99.9, median diameter: 0.14 μm) was used as the fluoride powder.

[0054] After the heat treatment of the test piece powder, each sintered compact was ultrasonically cleaned in ion-exchanged water and ethyl alcohol, and the polished surface in contact with the fluoride powder of the test piece was subjected to component analysis and surface observation using a scanning electron microscope equipped with an energy dispersive X-ray analyzer (SEM-EDS, manufactured by JEOL Ltd., JSM-IT210). As a result of the component analysis, it was confirmed that fluorine was detected from all the sintered compacts and a reaction layer was formed on the surface layer.

[0055] In addition, surface photographs (secondary electron images obtained with a scanning electron microscope: JSM-IT510 manufactured by JEOL Ltd., magnification: 200 times) of each of the test specimens of Examples 1 to 3 and Comparative Examples 1, 2, 4, and 5 after the reaction test with fluoride are shown in FIGS. 1 to 7. From these surface photographs, as shown in "Table 2" below, the following was found. In Examples 1 and 2, no cracks were observed on the observation surface, and in Example 3, minute cracks were observed in the very surface layer. On the other hand, no cracks were observed in Comparative Example 1, but a large number of macroscopic cracks that were clearly open were observed in Comparative Examples 2, 4, and 5.

[0056]

Table 2

[0057] From the results shown in the above-mentioned "Table 1" and "Table 2", the following was found. Examples 1 to 3 are clearly superior in plasma resistance to Comparative Examples 2 to 4 with respect to CF-based plasma, and have plasma resistance comparable to that of Comparative Example 2. Examples 1 to 3 and Comparative Example 1 do not produce macroscopic cracks even when a reaction layer with fluorine is formed on the surface, while a large number of macroscopic cracks are generated in Comparative Examples 2, 4, and 5. Comparative Example 1 does not produce macroscopic cracks even when a reaction layer with fluorine is formed on the surface, but its plasma resistance to CF-based plasma is inferior to that of Examples 1 to 3.

[0058] (Examples 4 and 5 and Comparative Examples 6 and 7) In the same manner as in Examples 1 to 3 and Comparative Examples 1 to 5 described above, in order to produce raw materials for thermal spraying having the compositions of Examples 4 and 5 and Comparative Examples 6 and 7 shown in the following "Table 3", first, a sintered body having the composition shown in "Table 3" was manufactured.

[0059] Using such a sintered body, raw materials for thermal spraying were produced by the granulation and firing method described below. In Comparative Example 7, the prepared coarse raw material of Y2O3 was used as it was. Using ion-exchanged water as a solvent, a carboxymethyl cellulose-based binder (manufactured by Kimica Corporation, PL-4) and a carboxylic acid-based peptizing agent (manufactured by Kao Chemicals, Kao Celra 2020) were added to prepare a slurry with a solid content of 40% by weight. These slurries were granulated using a spray dryer (manufactured by Okawara Chemical Machinery Co., Ltd., L-8).

[0060] The granulated particles were heat-treated and fired in the atmosphere at 1200 °C for 1 hour using an electric furnace to remove organic components and increase particle strength. The granulated particles crushed after such heat treatment were sieved into 20 μm to 53 μm and subjected to a spraying test. When measuring the particle size distribution of the tested granulated particles, the median diameters of the granulated particles in Examples 4 and 5 and Comparative Examples 6 and 7 were all within the range of 30 to 35 μm.

[0061] The spraying test was carried out under the following conditions by the atmospheric pressure plasma spraying method. In order to suppress the amorphization of the coating due to rapid cooling during spraying, the sprayed sample substrate was fixed to a stage with a heating heater, and the preheating and cooling rates were adjusted. Spraying device: Plasma spraying gun (9MB manufactured by Sulzer Metco) Operating voltage: 65 V Operating current: 700 A Primary gas: Ar Secondary gas: H2 Spraying distance: 140 mm Substrate: Aluminum alloy (plate-shaped body with a length of 20 mm, a width of 20 mm, and a thickness of 3 mm) Sprayed film thickness: Approximately 200 μm

[0062] The film surface of the sprayed sample prepared by the above spraying test was mirror-polished, and the deposited crystal phases were identified by qualitative analysis using XRD in the same manner as in Examples 1 to 3 and Comparative Examples 1 to 3. After classifying the detected crystal phases into main constituent phases and sub-constituent phases based on a calibration curve prepared in advance, the results of the plasma exposure test are shown in the following "Table 3". The devices and conditions used in the plasma exposure test are the same as those in Examples 1 to 3 and Comparative Examples 1 to 3.

[0063]

Table 3

[0064] As shown in the above "Table 3", the plasma consumption rates of Examples 4 and 5 were smaller than that of Comparative Example 6 and were close to the consumption rate of Comparative Example 7. Since pores and fine cracks generally exist in the sprayed coating, the plasma consumption rate thereof is larger than that of the sintered body having the same composition. However, the relationship between the composition and the consumption rate was the same for the sprayed sample and the sintered body.

[0065] As shown in the above "Table 3", in Example 4, Er3Al5O 12 and ErAlO3 were the main constituent phases, and a small amount of Er2O3 was present. In Example 5, ErAlO3 and Er4Al2O9 were the main constituent phases, and a small amount of Er3Al5O 12 was present. When the cross section of the sprayed film of Example 4 was observed, the number of cracks was small, and the propagation of cracks stopped at the interfaces of different crystal phases, and no macroscopic cracks were confirmed.

Industrial Applicability

[0066] The film-forming material, film-forming method, and coating of the present invention, particularly the sprayed film, are particularly effective in members for plasma etching apparatuses that use halogen gases such as fluorine gas in semiconductor manufacturing processes.

Claims

Claim 1 (a) A film-forming material containing a composite oxide of two or more types of Er ２ O ３ -Al ２ O ３ or (b) A film-forming material containing a composite oxide of one or more types of Er ２ O ３ -Al ２ O ３ and Er ２ O ３ and being such that In the above (a), the total molar amount of the two or more types of Er ２ O ３ -Al ２ O ３ The molar amount of Er ２ O ３ in terms of the total molar amount of the composite oxide, or in the above (b), the molar amount of Er ２ O ３ -Al ２ O ３ The composite oxide and the molar amount of Er ２ O ３ in terms of the total molar amount of Er ２ O ３ are both 38 to 75 mol%, and the film-forming material is characterized by this. Claim 2 In the above (a), the total molar amount of the two or more types of Er ２ O ３ -Al ２ O ３ The molar amount of Er ２ O ３ in terms of the total molar amount of the composite oxide, or in the above (b), the total molar amount of the one or more types of Er ２ O ３ -Al ２ O ３ composite oxide and the Er ２ O ３ The molar amount of Er ２ O ３ in terms of the total molar amount of the composite oxide is 55 to 66 mol% in each case. The film-forming material according to claim 1. Claim 3 In the above (a), the two or more types of Er ２ O ３ -Al ２ O ３ The complex oxide is Er ３ Al 5 O １２ and ErAlO 3 The film-forming material according to claim 1 or 2, which is as described above. Claim 4 In the above (a), the two or more types of Er ２ O ３ -Al ２ O ３ The complex oxide is ErAlO 3 and Er 4 Al ２ O ９ The film-forming material according to claim 1 or 2, which is as described above. Claim 5 In the above (a), the two or more types of Er ２ O ３ -Al ２ O ３ composite oxide is Er ３ Al ５ O １２ , ErAlO ３ , and Er ４ Al ２ O ９ The film-forming material according to claim 1 or 2, which is as described above. Claim 6 In the above (b), the one or more Er ２ O ３ -Al ２ O ３ composite oxide is Er ３ Al ５ O １２ and ErAlO ３ The film-forming material according to claim 1 or 2, which is as described above. Claim 7 In the above (b), the one or more Ers ２ O ３ -Al ２ O ３ The complex oxide is ErAlO ３ and Er ４ Al ２ O ９ The film-forming material according to claim 1 or 2, which is as described above. Claim 8 In the above (b), the one or more Ers ２ O ３ -Al ２ O ３ The complex oxide is Er ４ Al ２ O ９ The film-forming material according to claim 1 or 2, which is Claim 9 In the above (b), the one or more Er ２ O ３ -Al ２ O ３ composite oxide is Er ３ Al ５ O １２ , ErAlO ３ , and Er ４ Al ２ O ９ The film-forming material according to claim 1 or 2, which is as described above. Claim 10 A film forming method by spraying using the film forming material according to Claim 1 or 2. Claim 11 A method for manufacturing a member for a plasma etching apparatus, which forms a sprayed film on a substrate by the film forming method according to Claim 10. Claim 12 (a) A thermal spray coating containing a composite oxide of two or more kinds of Er ２ O ３ -Al ２ O ３ or (b) a thermal spray coating containing a composite oxide of one or more kinds of Er ２ O ３ -Al ２ O ３ and Er ２ O ３ and being such a thermal spray coating In the above (a), the total molar amount of the two or more kinds of Er ２ O ３ -Al ２ O ３ The conversion molar amount of Er ２ O ３ with respect to the total molar amount of the composite oxide, or, in the above (b), the total molar amount of the one or more kinds of Er ２ O ３ -Al ２ O ３ The conversion molar amount of Er ２ O ３ with respect to the composite oxide and the total molar amount of Er ２ O ３ is both 38 to 75 mol%, and the thermal spray coating is characterized by this. Claim 13 In the above (a), the total molar amount of the two or more types of Er ２ O ３ -Al ２ O ３ The conversion molar amount of Er ２ O ３ with respect to the total molar amount of the composite oxide, or in the above (b), the total molar amount of the one or more types of Er ２ O ３ -Al ２ O ３ The conversion molar amount of Er ２ O ３ with respect to the composite oxide and the total molar amount of the Er ２ O ３ is in each case 55 to 66 mol% according to claim 12. The thermal spray coating. Claim 14 In the above (a), the two or more types of Er ２ O ３ -Al ２ O ３ The complex oxide is Er ３ Al 5 O １２ and ErAlO 3 The thermal spray coating according to claim 12 or 13, which is as described above. Claim 15 In the above (a), the two or more types of Er ２ O ３ -Al ２ O ３ composite oxide is ErAlO 3 and Er 4 Al ２ O ９ The thermal spray coating according to claim 12 or 13, which is such. Claim 16 In the above (a), the two or more types of Er ２ O ３ -Al ２ O ３ The composite oxide is Er ３ Al ５ O １２ , ErAlO ３ , and Er ４ Al ２ O ９ The thermal spray coating according to claim 12 or 13, wherein the thermal spray coating is such. Claim 17 In the above (b), the one or more Ers ２ O ３ -Al ２ O ３ The complex oxide is Er ３ Al ５ O １２ and ErAlO ３ The sprayed film according to claim 12 or 13, which is as described above. Claim 18 In the above (b), the one or more Ers ２ O ３ -Al ２ O ３ The complex oxide is ErAlO ３ and Er ４ Al ２ O ９ The thermal spray coating according to claim 12 or 13, which is Claim 19 In the above (b), the one or more Er ２ O ３ -Al ２ O ３ The complex oxide is Er ４ Al ２ O ９ The thermal spray coating according to claim 12 or 13, which is Claim 20 In the above (b), the one or more Er ２ O ３ -Al ２ O ３ composite oxide is Er ３ Al ５ O １２ , ErAlO ３ , and Er ４ Al ２ O ９ The sprayed film according to claim 12 or 13, which is Claim 21 A member for a plasma etching apparatus, comprising the sprayed film according to Claim 12 or 13.

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