Plasma-resistant member

Abstract

To provide a plasma-resistant member in which an etching rate is reduced.SOLUTION: In the plasma-resistant member, when the mass of a sintered body is taken as 100, the content of magnesium oxide (MgO) is at least 95. The sintered body may further contain aluminum (Al) and calcium (Ca). When the mass of magnesium oxide (MgO) is taken as 100, the total content of aluminum and calcium, converted into alumina (Al2O3) and calcium oxide (CaO), respectively, is at least 0.04 and not more than 2.3.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a plasma-resistant member. [Background technology]

[0002] Semiconductor manufacturing equipment used in dry processes and plasma coating in semiconductor manufacturing employs highly reactive halogen-based plasma for etching and cleaning. Therefore, the components used in such equipment must be highly corrosion-resistant, and even higher corrosion resistance is required for components that come into contact with silicon (Si) wafers, such as electrostatic chucks and heaters, as well as the chambers and chamber parts that cover them. Sintered bodies of alumina (Al2O3) and yttria (Y2O3) are known to meet these corrosion-resistant requirements. Semiconductor manufacturing equipment using sintered bodies of Y2O3 are disclosed, for example, in Patent Documents 1 to 3. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-278935 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-179080 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-69843 Summary of the Invention [Problem to be solved by the invention]

[0004] Although corrosion-resistant members can be obtained by the techniques described in the above Patent Documents 1 to 3, there is a need for the development of sintered materials that can further reduce the etching rate. Note that this problem is not limited to semiconductor manufacturing equipment, but is a common problem for various members that are exposed to halogen-based plasma, such as base materials that are plasma-coated and water-repellent processing members such as nozzles that irradiate plasma gas. [Means for solving the problem]

[0005] The present disclosure has been made to solve at least one of the above-mentioned problems, and can be realized in the following forms.

[0006] (1) According to one embodiment of the present disclosure, there is provided a plasma-resistant member including a sintered body. In this plasma-resistant member, the sintered body has a magnesium oxide (MgO) content of 95 or more when the mass of the entire sintered body is taken as 100. Here, the plasma-resistant member refers to a part that is corrosion-resistant (hard to be etched) by plasma such as a halogen-based gas.

[0007] With this type of plasma-resistant member, the etching rate can be reduced and the halogen-based gas corrosion resistance (also referred to as plasma resistance) can be improved compared to when a sintered body containing mainly alumina (Al2O3) or yttria (Y2O3) is used or when a sintered body with a magnesium oxide (MgO) content of less than 95% is used. Therefore, when the plasma-resistant member is exposed to halogen-based plasma, the amount of dust generated can be reduced and the durability of the plasma-resistant member can be improved.

[0008] (2) In the plasma-resistant member of the above aspect, the sintered body may have a total content of aluminum (Al) and calcium (Ca) converted into alumina (Al2O3) and calcium oxide (CaO) of 0.04 or more and 2.3 or less, respectively, when the mass of magnesium oxide (MgO) is taken as 100. In this way, it is possible to improve plasma resistance while ensuring sinterability.

[0009] (3) In the plasma-resistant member of the above aspect, the sintered body may have a calcium (Ca) content, calculated as calcium oxide (CaO), of 0.01 or more and 0.5 or less when the mass of magnesium oxide (MgO) is taken as 100. In this way, the plasma resistance can be further improved while ensuring sinterability.

[0010] The present invention can be realized in various forms, for example, in the form of a semiconductor manufacturing equipment component, a semiconductor manufacturing equipment, a holding device, an electrostatic chuck, a water-repellent member, an apparatus including any of these, a method for manufacturing a semiconductor manufacturing equipment component, a method for manufacturing a water-repellent member, etc. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an explanatory diagram schematically illustrating a plasma device including a plasma-resistant member. [Figure 2] FIG. 10 is a diagram showing the evaluation results of the examples. DETAILED DESCRIPTION OF THE INVENTION

[0012] <Embodiment> 1 is an explanatory diagram schematically illustrating a plasma device 100 equipped with a plasma-resistant member according to an embodiment of the present disclosure. The plasma device 100 includes a reaction vessel 20 equipped with a vessel body 21 and a lid member 22, a holding device 30 for holding a substrate W, and a gas nozzle 10 as a plasma-resistant member.

[0013] Examples of the plasma device 100 include a film forming device for forming a thin film on a substrate W such as a semiconductor wafer or a glass substrate in a semiconductor manufacturing process, a water-repellent processing process, or a liquid crystal manufacturing process, or an etching device for performing micro-processing on a substrate W.

[0014] For example, in a film forming apparatus, a source gas containing a halogen-based corrosive gas is introduced into a reaction vessel 20 using a gas nozzle 10, and a thin film is formed on a substrate W by a plasma CVD (Chemical Vapor Deposition) method in which the source gas is converted into plasma. Also, in an etching apparatus, a halogen-based corrosive gas is introduced into a reaction vessel 20 using a gas nozzle 10 as a source gas, and the corrosive gas is converted into plasma to form an etching gas, thereby performing microfabrication on the substrate W.

[0015] The gas nozzle 10 has a gas supply port 11 through which gas such as a corrosive gas is supplied from a gas supply unit not shown, a gas exhaust port 12 through which gas is discharged into the reaction vessel 20, and a nozzle hole 13 that connects the gas supply port 11 and the gas exhaust port 12.

[0016] In this embodiment, the gas nozzle 10 as a plasma-resistant member has a sintered body in at least a part of the portion exposed to the corrosive gas, for example, the portion including the nozzle hole 13 and the portion exposed to the inside of the reaction vessel 20, and the entire gas nozzle 10 may be made of a sintered body. Furthermore, another layer such as a coating layer may be provided on the surface of the sintered body.

[0017] The plasma-resistant member includes a sintered body, and the sintered body has a magnesium oxide (MgO) content of 95 or more when the mass of the entire sintered body is taken as 100. This makes it possible to reduce the etching rate and improve plasma resistance compared to when a sintered body mainly containing alumina (Al2O3) or yttria (Y2O3) is used, or when a sintered body with a magnesium oxide (MgO) content of less than 95 is used. Therefore, when the plasma-resistant member is exposed to halogen-based plasma, the amount of dust generated can be reduced, and the durability of the plasma-resistant member can be improved.

[0018] From the viewpoint of plasma resistance, the magnesium oxide (MgO) content is preferably 100%. However, aluminum (Al) and calcium (Ca) derived from alumina (Al2O3) and calcium oxide (CaO) may be included as sintering aids added to ensure sinterability. Furthermore, unavoidable impurities such as Na2O, K2O, and SiO2 may be included.

[0019] The aluminum (Al) and calcium (Ca) contents of the sintered body are not particularly limited. However, when the mass of magnesium oxide (MgO) is taken as 100, the total aluminum (Al) and calcium (Ca) contents, converted into alumina (Al2O3) and calcium oxide (CaO), are preferably 0.04 to 2.3. This ensures improved plasma resistance while ensuring sinterability. Here, since it is preferable to include a certain amount of both alumina (Al2O3) and calcium oxide (CaO) as sintering aids from the perspective of sinterability, the aluminum (Al) and calcium (Ca) contents are shown as the total converted into alumina (Al2O3) and calcium oxide (CaO). Furthermore, the ratio of the aluminum (Al) and calcium (Ca) contents to magnesium oxide (MgO) is important.

[0020] The content of calcium (Ca) contained in the sintered body is not particularly limited, but it is preferable that the content of calcium (Ca) converted to calcium oxide (CaO) is 0.01 or more and 0.5 or less when the mass of magnesium oxide (MgO) is taken as 100. In this way, it is possible to further improve plasma resistance while ensuring sinterability.

[0021] As described above, the plasma-resistant member of this embodiment can reduce the etching rate and improve plasma resistance compared to when a sintered body containing mainly alumina (Al2O3) or yttria (Y2O3) is used. Therefore, in the plasma device 100, particle generation can be reduced and product yield can be improved. Furthermore, in the plasma device 100, the frequency of replacing the plasma-resistant member (gas nozzle 10) can be reduced.

[0022] In the plasma device 100, the reaction vessel 20 and the holding device 30 may be made of plasma-resistant materials. [Example]

[0023] The present disclosure will be explained more specifically with reference to examples. 2 shows the evaluation results of samples S1 to S19. Using samples S1 to S19 of sintered bodies with different compositions and manufacturing conditions, the number of grain boundary pores, MgO content, CaO content, Al2O3 content, MgAl2O4 content, and etching rate were evaluated. Samples S17 to S19 are comparative examples that do not satisfy the conditions for the sintered bodies described in the embodiment.

[0024] 1. Sample Preparation The manufacturing method for porous sintered bodies involves the blending process followed by the hot-pressing process. First, in the blending process P1, inorganic components and a binder dispersant are added to a solvent and then ground and mixed using a ball mill. The inorganic components are the inorganic components that form the main phase, plus auxiliary materials such as calcium carbonate (CaCO3) and alumina (Al2O3). The inorganic components vary depending on the sample. In the hot-pressing process, the slurry obtained in the blending process is hot-pressed at 1250°C to 1540°C in an inert atmosphere (Ar, vacuum, etc.). This produces a sintered body. Hot-pressing applies pressure during firing, which crushes particles during firing compared to atmospheric pressure firing, promoting densification and reducing grain boundary pores. Furthermore, the contact area between particles is larger, allowing the sintering process itself to be completed in a shorter time than air firing. The sample size is 15mm x 15mm x 2mm (thickness).

[0025] [Samples S1-S14, S17] In samples S1 to S14 and S17, magnesium oxide (MgO) was used as the inorganic component that forms the main phase, and calcium carbonate (CaCO3) and alumina (Al2O3) were used as auxiliary components. The inorganic components were mixed in the proportions shown in Figure 2 and hot-pressed in an argon (Ar) atmosphere at 1250°C and 55 MPa for 3 hours.

[0026] [Samples S15, S16] Samples S15 and S16 used magnesium oxide (MgO) as the inorganic component that forms the main phase, with zinc oxide (ZnO) and titanium dioxide (TiO2) as auxiliary components. The inorganic components were mixed in the proportions shown in Figure 2 and hot-pressed for 3 hours at 1250°C and 55 MPa in an argon (Ar) atmosphere. In Figure 2, the CaO content column shows the ZnO content, the Al2O3 content column shows the TiO2 content, and the total column shows the sum of ZnO and TiO2.

[0027] [Sample S18] Sample S18 used yttria (YO) as the inorganic component that forms the main phase, with calcium carbonate (CaCO) and alumina (AlO) as auxiliary components. The inorganic components were mixed in the proportions shown in Figure 2 and hot-pressed in a vacuum atmosphere at 1400°C and 50 MPa for 3 hours. In Figure 2, the CaO and AlO contents are shown as a percentage of the YO content, which is taken as 100.

[0028] [Sample S19] Sample S19 used alumina (Al2O3) as the inorganic component that forms the main phase, and calcium carbonate (CaCO3) as an auxiliary. The inorganic components were mixed in the proportions shown in Figure 2, and hot-pressed in an argon (Ar) atmosphere at 1540°C and 20 MPa for 4 hours. In Figure 2, the CaO content is shown as a percentage when the Al2O3 content is taken as 100. Since the main component of sample S19 is Al2O3, the Al2O3 content is not shown in Figure 2.

[0029] 2.Measurement method [Number of grain boundary pores] The SEM (Scanning Electron Microscope) images at 2000x magnification were measured using WinROOF (image analysis and measurement software) in terms of the equivalent circle diameter. A total of 10.8 mm was measured across four fields of view. 2 The number of pores with a diameter of 0.3 μm or more per unit area was counted.

[0030] [MgO content, CaO content, Al2O3 content, ZnO content, TiO2 content] Quantitative analysis was performed using X-ray fluorescence analysis (XRF). In Figure 2, the MgO content is shown as a percentage of the entire sintered body, which is 100, and the CaO content, Al2O3 content, ZnO content, and TiO2 content are shown as percentages of the MgO content, which is 100.

[0031] [MgAl2O4 content] Quantitative analysis was performed using X-ray diffraction (XRD). Figure 2 shows the percentage of MgO, with the amount of MgO taken as 100.

[0032] [Etching rate] Each sample was partially masked and subjected to a plasma resistance test (etching) under the following conditions. After the plasma resistance test, the masking was removed from the sample, and the step between the etched and masked areas was measured using a stylus-type step gauge. This step was taken as the amount of etching. In Figure 2, the etching rate is expressed as a relative value based on the amount of etching of sample S18 (a sintered compact whose main phase is Y2O3). As shown in Figure 2, the etching rate of sample S18 is "1". Test conditions Microwave excited plasma: 2000W Bias: 200W Etching gas: NF3 Pressure: 20mtorr NF3 flow rate: 20sccm (standard cubic centimetre / min) Irradiation time: 10 hours

[0033] 3.Measurement results As shown in FIG. 2, samples S1 to S16 satisfy the following requirement [1]. [1] When the mass of the entire sintered body is taken as 100, the content of magnesium oxide (MgO) is 95 or more. Samples S1 to S16 have smaller etching rates than sample S17. Sample S17 has a magnesium oxide (MgO) content of less than 95%. That is, it was confirmed that by satisfying the above requirement [1], it is possible to improve the plasma resistance compared to a sintered body having a magnesium oxide (MgO) content of less than 95%. Samples S1 to S16 have smaller etching rates than sample S18. Sample S18 is a sintered body having Y2O3 as the main phase. It was confirmed that by satisfying the above requirement [1], it is possible to improve the plasma resistance compared to a sintered body having Y2O3 as the main phase. Furthermore, Samples S1 to S16 have smaller etching rates than sample S19. Sample S19 is a sintered body having Al2O3 as the main phase. That is, it was confirmed that by satisfying the above requirement [1], it is possible to improve the plasma resistance compared to a sintered body having Al2O3 as the main phase.

[0034] Samples S1 to S16 have fewer grain boundary pores than Sample 18. It has been confirmed that Samples S1 to S16, by satisfying the above requirement [1], can have improved density compared to a sintered body having Y2O3 as the main phase, and can also have improved plasma resistance. In addition, Samples S1 to S16 have the same or less grain boundary pores as Sample 1. It has been confirmed that Samples S1 to S16, by satisfying the above requirement [1], can have improved density compared to a sintered body having Al2O3 as the main phase, and can also have improved plasma resistance.

[0035] In addition, although samples S14 and S15 contained different types of auxiliary agents, they had the same magnesium oxide (MgO) content and had similar etching rates. This confirmed that if the above requirement [1] is met, plasma resistance can be improved regardless of the remaining composition.

[0036] Samples S1 to S9 further satisfy the following requirement [2]. [2] When the mass of magnesium oxide (MgO) in the sintered body is taken as 100, the total content of aluminum (Al) and calcium (Ca), converted into alumina (Al2O3) and calcium oxide (CaO), is 0.04 or more and 2.3 or less, respectively.

[0037] The etching rates of samples S1 to S9 are even smaller than those of samples S10 to S16. That is, it was confirmed that by satisfying the above requirement [2], the plasma resistance can be further improved (etching rate is smaller than 0.8).

[0038] Samples 1 to 7 further satisfy the following requirement [3]. [3] When the mass of magnesium oxide (MgO) of the sintered body is taken as 100, the calcium (Ca) content is 0.01 or more and 0.5 or less in terms of calcium oxide (CaO).

[0039] The etching rates of Samples 1 to 7 are even smaller than those of Samples S8 to S16. That is, it was confirmed that by satisfying the above requirement [3], the plasma resistance can be further improved (etching rate is smaller than 0.8).

[0040] Samples S11 to S13 contain a relatively large amount of alumina (Al2O3) as a sintering aid, forming spinel (MgAl2O4) in the sintered body, and have relatively high etching rates, although lower than those of samples S17 to S19. Furthermore, comparing samples S10 and S14, the alumina (Al2O3) content is relatively low at 1.5, meaning that spinel (MgAl2O4) is not formed. However, sample S14 has a higher calcium oxide (CaO) content than sample S10, resulting in a relatively high etching rate. In other words, in a sintered body primarily composed of magnesium oxide (MgO), the absence of a spinel (MgAl2O4) phase improves corrosion resistance, but it was confirmed that reducing the amount of alumina (Al2O3) and increasing the amount of calcium oxide (CaO) too much also reduces corrosion resistance.

[0041] <Modification of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.

[0042] The method for producing the sintered body is not limited to the above-described examples. By appropriately changing the type and amount of additive, firing method, firing atmosphere, firing temperature, hot press pressure, etc., it is possible to produce a sintered body having a magnesium oxide (MgO) content of 95% or more when the mass of the entire sintered body is taken as 100%. Alternatively, the sintered body may be produced by other known methods, such as gel casting.

[0043] In the above examples, the sintered body contains Ca, Al, Zn, and Ti in addition to magnesium oxide (MgO), but other components may also be included. For example, various metals contained in sintering aids may also be included. Furthermore, unavoidable impurities such as components contained in raw materials and components mixed in during the manufacturing process may also be included.

[0044] The present disclosure has been described above based on embodiments, examples, and modifications. However, the above-described embodiments are intended to facilitate understanding of the present disclosure and are not intended to limit the present disclosure. The present disclosure may be modified or improved without departing from the spirit and scope of the claims, and equivalents thereof are included in the present disclosure. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

[0045] The present invention can also be realized as the following application examples. [Application example 1] A plasma-resistant member including a sintered body, The sintered body is The sintered body is characterized in that the content of magnesium oxide (MgO) is 95 or more when the mass of the entire sintered body is 100. Plasma resistant materials. [Application example 2] The plasma-resistant member according to Application Example 1, The sintered body is The total content of aluminum (Al) and calcium (Ca) converted into alumina (Al2O3) and calcium oxide (CaO) is 0.04 or more and 2.3 or less when the mass of magnesium oxide (MgO) is 100, Plasma resistant materials. [Application example 3] The plasma-resistant member according to Application Example 1 or Application Example 2, The sintered body is The calcium (Ca) content is 0.01 or more and 0.5 or less in terms of calcium oxide (CaO) when the mass of magnesium oxide (MgO) is 100. Plasma resistant materials. [Explanation of symbols]

[0046] 10...Gas nozzle 11...Gas supply port 12...Gas outlet 13...Nozzle hole 20...Reaction vessel 21...Container body 22...Lid part 100...Plasma device W...Substrate

Claims

1. A plasma-resistant member including a sintered body, The sintered body is The sintered body is characterized in that the content of magnesium oxide (MgO) is 95 or more when the mass of the entire sintered body is 100. Plasma resistant materials.

2. The plasma-resistant member according to claim 1, The sintered body is When the mass of magnesium oxide (MgO) is 100, the content of aluminum (Al) and calcium (Ca) is 100% of alumina (Al 2 O 3 ) and calcium oxide (CaO), the total of which is 0.04 or more and 2.3 or less, Plasma resistant materials.

3. The plasma-resistant member according to claim 2, The sintered body is The present invention is characterized in that the content of calcium (Ca) is 0.01 or more and 0.5 or less in terms of calcium oxide (CaO) when the mass of magnesium oxide (MgO) is 100. Plasma resistant materials.

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