Component for plasma processing device, plasma processing device having the component, and method of using sintered body

Abstract

The present invention provides a component for a plasma processing device, a plasma processing device having the component, and a method for using a sintered body. The component for a plasma processing device has a tungsten carbide phase and a subphase, the subphase comprising at least one selected from the group consisting of phase I, phase II, phase III, phase IV, and phase V, phase I is a carbide phase having at least one of the elements of the fourth group, the fifth group, and the sixth group of the periodic table other than W as a constituent element, phase II is a nitride phase having at least one of the elements of the fourth group, the fifth group, and the sixth group of the periodic table other than W as a constituent element, phase III is a carbonitride phase having at least one of the elements of the fourth group, the fifth group, and the sixth group of the periodic table other than W as a constituent element, phase IV is a carbon phase, and phase V is a carbon phase consisting of W. x M y C z The composite carbide phase represented by the formula has a content ratio of 99 volume % or more of the tungsten carbide phase, a content ratio of the subphase is 1 volume % or less, and a porosity of 2 volume % or less.

Description

Technical Field

[0001] The present disclosure relates to a component for a plasma processing device, a plasma processing device having the component, and a method of using a sintered body. Background Art

[0002] Components installed in a chamber of a plasma etching device or the like in semiconductor manufacturing are exposed to a corrosive environment formed by the plasma of an etching gas used to form a semiconductor pattern or the like. If such components are made of a material that reacts with an etchant, they may contaminate the chamber and the etched object (e.g., a semiconductor wafer), and may cause poor insulation and poor shape. In order to suppress this phenomenon, the use of silicon (Si) or quartz as components has been studied.

[0003] For example, in Patent Document 1 (Japanese Patent Publication No. 2001-135619), in order to prevent contamination caused by impurities such as heavy metals, an edge ring made of single crystal silicon is proposed. In Patent Document 2 (Japanese Patent Publication No. 62-047130), SiC, WC, TiC, etc. are proposed as the material of the wafer ring. In Patent Document 3 (Japanese Patent Publication No. 2018-107433), SiC, Si, SiO, etc. are listed as the materials of the edge ring. 2 , W, WC, etc. In addition to these materials, aluminum or aluminum alloys that are cheap and easy to manufacture, aluminum subjected to anodizing treatment, and parts obtained by spraying yttrium oxide having high corrosion resistance on a base material such as aluminum are also known.

[0004] However, among the above materials, aluminum is not sufficiently resistant to plasma corrosion, and there is a concern that the frequency of component replacement will increase due to consumption. Although it is conceivable to provide a corrosion-resistant layer as a countermeasure, if a corrosion-resistant layer is provided, particles may be generated. In addition, metal ions such as aluminum and yttrium have an adverse effect on semiconductor circuits and may cause malfunctions and failures.

[0005] Since silicon and quartz are also easily eroded by plasma, the replacement frequency of parts increases. In addition, among ceramics, tungsten carbide (WC) is an excellent material with high strength and is not easy to generate static electricity because of its high conductivity. However, WC itself has a high melting point and is a difficult sintering material, and it is difficult to obtain a sintered body with few pores that can become a particle bag. The so-called superhard alloy obtained by adding a certain amount of metal binders such as Co and Ni to WC can reduce pores, but the metal binder components such as Co and Ni may contaminate the chamber of the plasma processing device and may become a factor in the generation of particles. This metal contamination is particularly easy to occur when the metal component is contained as a "phase". This is because the etching speed (etching rate) of the carbide phase and the metal phase to the plasma gas is different. In the case of the metal phase, the metal part is corroded first, releasing a large amount of contaminated metal. Summary of the invention

[0006] Therefore, the present disclosure provides a component for a plasma processing device that has excellent corrosion resistance to plasma processing and can fully suppress metal contamination in the plasma processing device. In addition, a plasma processing device that has excellent corrosion resistance and can fully suppress metal contamination in the device is provided. In addition, the present disclosure provides a method of using a sintered body that has excellent corrosion resistance to plasma processing and can fully suppress metal contamination in the plasma processing device as a component of a plasma processing device.

[0007] The present disclosure provides, on one hand, a component (sintered body) for a plasma processing device, which has a tungsten carbide phase and a subphase, wherein the subphase is dispersed in the tungsten carbide phase and contains at least one selected from the group consisting of the following (phase I), (phase II), (phase III), (phase IV) and (phase V), the content of the tungsten carbide phase is greater than 99 volume %, the content of the subphase is less than 1 volume %, and the porosity is less than 2 volume %.

[0008] (Phase I) A carbide phase having at least one of the elements of Group IV, Group V and Group VI of the periodic table other than W as a constituent element

[0009] (Phase II) A nitride phase containing at least one of the elements of Group IV, Group V, and Group VI of the periodic table other than W as a constituent element

[0010] (Phase III) A carbonitride phase having at least one of the elements of Group IV, Group V, and Group VI of the periodic table other than W as a constituent element

[0011] (Phase IV) Carbon Phase

[0012] (Phase V) by W x M y C z A composite carbide phase represented by the formula (wherein M represents an iron group element, C represents carbon, W represents tungsten, and x, y, and z each represent a value greater than 0.)

[0013] Since the content ratio of the tungsten carbide phase is 99 volume % or more, the above-mentioned parts have excellent corrosion resistance to plasma treatment. In addition, since the porosity is 2 volume % or less, it is possible to reduce particle pockets generated by plasma treatment. In addition, since the content ratio of the tungsten carbide phase is high, the secondary phase is a component with relatively excellent corrosion resistance to plasma, and the content ratio of the secondary phase is 1 volume % or less, it is possible to fully suppress contamination in the plasma treatment device.

[0014] The present disclosure provides a plasma processing device including the above-mentioned component in another aspect. The plasma processing device includes the above-mentioned component. Therefore, it is possible to provide a plasma processing device that has excellent corrosion resistance and can sufficiently suppress contamination in the device.

[0015] The present disclosure provides a method of use on another aspect, which is a method of using a sintered body as a component of a plasma processing device, wherein the sintered body has a tungsten carbide phase and a subphase, the subphase is dispersed in the tungsten carbide phase, and contains at least one selected from the group consisting of the following (phase I), (phase II), (phase III), (phase IV) and (phase V), the content ratio of the tungsten carbide phase is greater than 99 volume %, the content ratio of the subphase is less than 1 volume %, and the porosity is less than 2 volume %.

[0016] (Phase I) A carbide phase having at least one of the elements of Group IV, Group V and Group VI of the periodic table other than W as a constituent element

[0017] (Phase II) A nitride phase containing at least one of the elements of Group IV, Group V, and Group VI of the periodic table other than W as a constituent element

[0018] (Phase III) A carbonitride phase having at least one of the elements of Group IV, Group V, and Group VI of the periodic table other than W as a constituent element

[0019] (Phase IV) Carbon Phase

[0020] (Phase V) by W x M y C z A composite carbide phase represented by the formula (wherein M represents an iron group element, C represents carbon, W represents tungsten, and x, y, and z each represent a value greater than 0.)

[0021] The present disclosure can provide a component for a plasma processing device that has excellent corrosion resistance to plasma processing and can fully suppress metal contamination in the plasma processing device. In addition, it can provide a plasma processing device that has excellent corrosion resistance and can fully suppress contamination in the device. In addition, it can provide a method of use, which uses a sintered body that has excellent corrosion resistance to plasma processing and can fully suppress metal contamination in the plasma processing device as a component of a plasma processing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic cross-sectional view showing one embodiment of a plasma processing apparatus. Figure 2 It is a diagram showing an overview of plasma etching processing. DETAILED DESCRIPTION

[0023] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings as appropriate. However, the following embodiment is an example for describing the present disclosure, and is not intended to limit the present disclosure to the following contents.

[0024] A component for a plasma processing device according to an embodiment of the present disclosure is composed of a sintered body and has a tungsten carbide phase and a subphase dispersed in the tungsten carbide phase. The subphase is composed of at least one phase selected from the group consisting of the following phase I, phase II, phase III, phase IV, and phase V. The content ratio of the tungsten carbide phase in the component is 99% by volume or more, and the total content ratio of the subphase, i.e., phase I, phase II, phase III, phase IV, and phase V in the component is 1% by volume or less. In addition, the porosity in the component is 2% by volume or less.

[0025] Phase I: A carbide phase containing at least one of the elements of Group 4, Group 5, and Group 6 of the periodic table other than W as a constituent element

[0026] Phase II: Nitride phase containing at least one of the elements of Group IV, Group V, and Group VI of the periodic table other than W as a constituent element

[0027] Phase III: Carbonitride phase containing at least one of the elements of Group IV, Group V, and Group VI of the periodic table other than W as a constituent element

[0028] Phase IV: Carbon Phase

[0029] Phase V: W x M y C z A composite carbide phase represented by the formula (wherein M represents an iron group element, C represents carbon, W represents tungsten, and x, y, and z each represent a value greater than 0.)

[0030] The tungsten carbide phase in the present disclosure is a crystalline phase of tungsten carbide. From the viewpoint of reducing the manufacturing cost of the component and fully reducing metal contamination, the content ratio of the tungsten carbide phase can be 99.3 to 99.99% by volume, or 99.5 to 99.95% by volume. The subphase is a crystalline phase selected from at least one of the groups consisting of the above-mentioned phase I, phase II, phase III, phase IV, and phase V. From the viewpoint of reducing the manufacturing cost of the component and fully reducing metal contamination, the content ratio of the subphase in the component can be 0.01 to 0.7% by volume, or 0.05 to 0.5% by volume. The volume ratio of each phase can be obtained by image processing of the image of the scanning electron microscope.

[0031] Trace impurities can be dissolved in the tungsten carbide phase and the subphase. The content of each of the Fe atoms, Co atoms and Ni atoms in the above-mentioned components can be 30 to 3300 atomic ppm, or 30 to 1650 atomic ppm. By containing iron group elements within this range, metal contamination can be fully reduced while reducing the manufacturing cost of the components. The content of each atom can be measured by glow discharge mass spectrometry (GDMS).

[0032] From the viewpoint of sufficiently reducing particle pockets and reducing manufacturing costs, the porosity of the member may be 0.05 to 1% by volume, or 0.1 to 0.5% by volume. The porosity can be calculated from the relative density obtained by the Archimedean method.

[0033] The "elements of Group 4, Group 5, and Group 6 of the periodic table other than W" in Phase I, Phase II, and Phase III include titanium (Ti), vanadium (V), chromium (Cr), zirconium (Zr), niobium (Nb), molybdenum (Mo), hafnium (Hf), and tantalum (Ta).

[0034] The "fourth group, fifth group, and sixth group elements of the periodic table other than W" in phase I, phase II, and phase III can be one or more elements selected from the group consisting of Ta, Nb, V, and Cr. By including these carbides, the mechanical strength can be improved. In addition, the effect of suppressing the abnormal grain growth of the tungsten carbide phase (WC phase) increases, and large-sized particle bags can be suppressed. In addition, if the number of particles increases, the effect of suppressing the abnormal grain growth of the tungsten carbide phase (WC phase) increases, and large-sized particle bags can be suppressed.

[0035] The "carbon phase" in phase IV may be any one or more substances selected from the group consisting of graphite, amorphous carbon, tubular carbon such as carbon nanotubes (CNTs), and thin plate carbon such as graphene.

[0036] The iron group element "M" in phase V is any one or more elements selected from the group consisting of iron (Fe), cobalt (Co) and nickel (Ni). The "complex carbide phase" of phase V is a composite carbide of tungsten (W) and an iron group element, for example, W 3 Co 3 C phase and W 3 Ni 3 C phase. From the viewpoint of maintaining sufficiently high resistance to plasma treatment, the content ratio of the composite carbide phase may be 0.5 volume % or less.

[0037] The carbides, nitrides and carbonitrides of phases I to III have the effect of inhibiting the abnormal grain growth of tungsten carbide (WC). At least a part of the carbides, nitrides and carbonitrides is dissolved in tungsten carbide, which has the effect of promoting sintering. In addition, the mechanical strength can be further improved by including carbides, nitrides and carbonitrides of phases I to III. As a result, it is also possible to deal with parts of shapes where strength becomes a problem when made of silicon, for example. The carbides, nitrides and carbonitrides of phases I to III are not inferior to tungsten carbide in terms of corrosion resistance, and are also very high. Therefore, the generation of particle bags can be fully suppressed. The carbide phase of phase I, the nitride phase of phase II and the carbonitride phase of phase III can be one kind respectively, or two or more kinds respectively. For example, phase I can be a composite carbide phase such as (Ti·Mo)C (different from phase V). Phase III can be a composite carbonitride phase such as (Ti·Mo)(C·N).

[0038] The carbon phase of phase IV has the effect of promoting the sintering of tungsten carbide. Compared with the tungsten carbide phase, the carbon phase has a faster plasma etching speed. However, by reducing the average particle size of the powder used as the raw material and adjusting the sintering conditions, phase IV can be finely and highly dispersedly included in the component. Thus, the generation of particles can be fully suppressed. In addition, since only carbon (C) is contained as a component, metal contamination can be prevented.

[0039] Phase V by W x M y C z The composite carbide of W and iron group (M) represented by the formula can be generated during the sintering of tungsten carbide. As a representative composition, the composition of x=3, y=3, z=1 can be exemplified. As another composition, it can be x=4, y=2, z=1, or it can be x=6, y=3, z=2. The composition is not limited to these. Compared with the tungsten carbide phase, the composite carbide has a slightly weaker corrosion resistance, but the composite carbide has the effect of promoting sintering. Therefore, a sintered body with few pores and less prone to particle pockets can be formed.

[0040] The secondary phase is any one of phases I to V, and compared with a component composed of a single tungsten carbide (tungsten carbide phase: 100 volume %), it is possible to further reduce pores and improve mechanical properties. In addition, it is possible to substantially reduce the effects of increased plasma etching rate, increased metal contamination, and increased particle pockets.

[0041] The “corrosion resistance” in the present disclosure refers to the corrosion resistance to plasma processing using a fluorocarbon-based or halogen-based etching gas.

[0042] The component may not contain any phase other than the tungsten carbide phase and the subphase. For example, it may not contain a metal phase (a phase of a metal or alloy that is not carbonized, etc.), and may only consist of a tungsten carbide phase and at least one subphase selected from the group consisting of phases I to V. However, the tungsten carbide phase and the subphase may contain trace impurities such as metal atoms. From the perspective of suppressing pollution, the metal content of the monomer relative to the entire component may be, for example, less than 3300 atomic ppm, less than 1650 atomic ppm, or less than 1000 atomic ppm. If a metal phase is included, this portion tends to be preferentially etched by plasma, resulting in bumps and depressions on the surface of the component and forming a particle bag. In addition, the metal phase is etched by plasma, and metal ions float, which tends to become a source of contamination for etched objects such as semiconductor wafers.

[0043] The total content of iron group elements (Fe atoms, Co atoms and Ni atoms) in the component can be 30 to 3300 atomic ppm. The iron group elements have the effect of promoting the sintering of tungsten carbide. If the total content of the iron group elements is less than 30 atomic ppm, the effect of promoting sintering tends to be weakened. On the other hand, if the total content of the iron group elements is greater than 3300 atomic ppm, fine phases of iron group metals are likely to appear in a part of the sintered body. From the viewpoint of sufficiently reducing the amount of particles generated during plasma treatment, the total amount (mol) of iron group elements in the component can be 30 to 2200 ppm, or 30 to 1650 ppm.

[0044] In the component of the present embodiment, the WC phase having excellent corrosion resistance to plasma treatment accounts for more than 99% by volume. Therefore, the etching speed of the component is extremely slow, and a long life can be achieved, for example, compared with a component composed of silicon. When there is no metal phase, there is no phase that is obviously easily corroded by plasma, so it is difficult to produce unevenness on the surface of the component due to the difference in etching speed. Therefore, it is difficult to produce particle bags and metal contamination can be suppressed. In addition, since the secondary phase has the effect of promoting sintering, the pores that cause the generation of particle bags in the component can be substantially reduced compared with pure tungsten carbide. By using such a component in a plasma processing device, the contamination in the etched object and the device can be reduced, the device life is prolonged, and the quality of products based on the semiconductor manufacturing process can be improved and the yield rate can be increased.

[0045] When plasma etching is performed by a plasma processing device, a material containing tungsten is sometimes used as a mask material. In this case, tungsten is used in the chamber, so the etched object is treated to remove tungsten. Therefore, the above treatment can remove contamination caused by the presence of tungsten in the component.

[0046] An example of a method for manufacturing a component for a plasma processing device is described below. As raw materials, a powder of tungsten carbide and a powder for generating a secondary phase are prepared. From the perspective of sufficiently reducing metal contamination, the purity of the tungsten carbide powder can be 99.5% by mass or more, or 99.8% by mass or more. Regarding the average particle size, from the perspective of sinterability and processability, it can be about 0.1 to 4 μm.

[0047] When forming phase I, phase II or phase III, as a raw material, a powder of carbide, nitride or carbonitride containing at least one of the elements of the fourth group, fifth group and sixth group of the periodic table other than W as a constituent element can be used. These have the effect of suppressing abnormal grain growth of the sintered body. Since the etching rate is different from that of WC, from the viewpoint of suppressing the generation of unevenness and reducing particle pockets, the average particle size of the powder can be 1 μm or less, 0.8 μm or less, or 0.6 μm or less.

[0048] When forming phase IV, any one or more selected from the group consisting of graphite, amorphous carbon and tubular carbon such as CNT is added. The carbon source can be fibrous carbon or layered carbon, or it can be a resin. When adding graphite, a powder with an average particle size of about 0.5 to 5 μm can be used. Since the carbon component exchanges carbon with WC during sintering, the particle size of the raw material is not necessarily consistent with the particle size of the carbon phase in the sintered body. For amorphous carbon and tubular carbon such as CNT, the average particle size can be less than 1 μm. When the raw material is anisotropic, its long side can be less than 1 μm.

[0049] When forming phase V, a metal powder of the iron group or a powder of a compound having the iron group as a constituent element can be used. The compound can be made into an aqueous solution or the like and mixed in an ionic state. In this way, the form of the raw materials is not particularly limited. Furthermore, the iron group metals (Fe, Ni, Co) can be mixed from the medium in the mixing and stirring step described later. The amount of the iron group can be more than 200 ppm on a mass basis relative to the entire raw material. The average particle size of the powder can be about 0.5 to 4 μm. If the average particle size becomes too large, the metal phase of the iron group tends to remain in the sintered body. Furthermore, when W is used as the raw material, the metal phase of the iron group tends to remain in the sintered body. 1 C 1-x When the tungsten carbide powder is represented by the composition formula of , phase V is easily formed by using a powder with a large x value (for example, 0.05≤x≤0.2). In addition, phase V is easily formed by mixing WC powder with a metal powder of the iron group or a powder of a compound having an iron group element as a constituent element for a long time and absorbing oxygen in the air. This is because decarburization is easily caused during sintering. In addition, from the viewpoint of easy decarburization, the sintering temperature can be set to a higher level.

[0050] The raw materials mentioned above are mixed and stirred by a known dry or wet method. The obtained mixed powder may be dried as needed, or an organic binder for molding may be added to obtain a mixed powder.

[0051] Next, the mixed powder is press-formed to obtain a molded body. Press-forming can be performed using a mold and a punch, or a wet punch using hydrostatic pressure. The maximum pressure during punching can be performed at about 10 to 500 MPa. The obtained molded body can be degreased, pre-sintered, or intermediately processed as needed.

[0052] The formed body or the processed body after degreasing, pre-sintering and intermediate processing is placed in a sintering furnace for sintering. Sintering can be carried out in a non-oxidizing atmosphere (hydrogen atmosphere, ammonia atmosphere, vacuum atmosphere containing carbon or rare gas atmosphere, etc.). Since tungsten carbide is a difficult-to-sinter material, the maximum temperature during sintering can be around 1800-2400°C.

[0053] After sintering, the sintered body can be subjected to HIP (hot isostatic pressing) treatment to further reduce residual pores. In addition, in the case of applications and shapes requiring dimensional accuracy, the sintered body can be subjected to various well-known surface treatments such as mechanical processing and electrical processing. In this way, a component for a plasma processing device composed of a sintered body can be obtained. The manufacturing method of the component is not limited to the above example, and hot pressing or SPS (spark plasma sintering) can be used according to the shape.

[0054] Tungsten carbide sometimes undergoes local reactions at high temperatures during sintering. Therefore, the volume ratio of the input raw materials is not necessarily the same as the volume ratio of the phases in the component. This is due to the following reasons: Tungsten carbide is not an ideal W 1 C 1 The stoichiometric ratio of W is 1, and the stoichiometric ratio of C is less than 1; solid solution of tungsten carbide and other carbides (or nitrides, carbonitrides) may occur; carbon exchange occurs between tungsten carbide and a carbon source other than tungsten carbide (for example, firing atmosphere, firing jig, etc.); iron group and tungsten generate composite carbides as compounds, etc.

[0055] In the sintered state, the proportion of phases other than the tungsten carbide phase in the plasma processing device component is 1 volume % or less in total. The raw material input and sintering conditions may be set so that the proportion of phases other than the tungsten carbide phase in the sintered body is reduced.

[0056] The sintered body has sufficient corrosion resistance for plasma treatment, so the life of the component can be extended, and the generation of particle bags and metal contamination can be fully suppressed. In addition, the sintered body has electrical conductivity. Therefore, it can be suitably used as a component for a plasma processing device used in a semiconductor manufacturing process. Specific components include an edge ring provided around a semiconductor wafer, an electrostatic chuck for adsorbing semiconductors, a wafer mounting substrate, a shower plate as a processing gas supply unit for etching, a core column of a water jacket as a structure for flowing cooling water, and a chamber inner wall material.

[0057] The secondary phase of the above-mentioned component can be phase V, and the complex carbide phase contains W 3 Co 3 C phase and W 3 Ni 3 One or both of the C phases.

[0058] The subphase of the component may be at least one selected from the group consisting of phase I, phase II and phase III, and the constituent elements of phase I, phase II and phase III include at least one selected from the group consisting of Cr, Ta, V and Nb. This increases the effect of suppressing abnormal grain growth and can suppress large-sized particle pockets.

[0059] The above-mentioned component can be composed of only tungsten carbide phase and carbide phase (phase I). In this way, sinterability can be improved and pores can be reduced. In addition, due to the improvement of mechanical strength, it can also be applied to parts with fragile shapes.

[0060] The above-mentioned component can be composed of only tungsten carbide phase and carbon phase (phase IV). Thus, sinterability can be improved and pores can be reduced. Moreover, compared with the case without phase IV, the processing load can be reduced and processing can be performed at low cost.

[0061] The above-mentioned component can be composed only of tungsten carbide phase and composite carbide phase (phase V). Thus, sinterability can be improved and pores can be reduced. In addition, the allowable range of impurities in the raw material and sintering conditions is wide, and the manufacturing is easy and low-cost.

[0062] The above-mentioned member may be composed only of the tungsten carbide phase, the carbide phase (phase I) and the composite carbide phase (phase V). Thus, the advantages of both the phase I and the phase V are obtained.

[0063] Figure 11 is a longitudinal sectional view showing an example of a plasma processing device 10 according to an embodiment. The plasma processing device 10 of the present embodiment is a capacitively coupled plasma (CCP) parallel plate plasma processing device. In the plasma processing device 10, a gas is converted into plasma in a chamber 11, and a wafer Wa placed on a mounting table 20 is processed by the action of plasma. The wafer Wa is, for example, a semiconductor wafer. The plasma processing device 10 is an example of a processing device.

[0064] The plasma processing apparatus 10 includes a substantially cylindrical chamber 11. The inner surface of the chamber 11 is subjected to anodizing treatment. The chamber 11 is divided into a processing chamber U for performing plasma etching treatment and film forming treatment on a wafer Wa.

[0065] The mounting table 20 includes the susceptor 18 and the electrostatic chuck 21, and mounts the wafer Wa. The mounting table 20 also functions as a lower electrode.

[0066] An electrostatic chuck 21 is provided on the susceptor 18. The electrostatic chuck 21 is formed into a structure in which a chuck electrode 21a is sandwiched between insulators 21b. A DC power source 22 is connected to the chuck electrode 21a via a switch 23. When the switch 23 is turned on, a DC voltage is applied from the DC power source 22 to the chuck electrode 21a. As a result, the wafer Wa is attracted to the electrostatic chuck 21 by the Coulomb force.

[0067] An annular edge ring 87 is placed around the wafer Wa and on the outer peripheral placement surface of the electrostatic chuck 21. The edge ring 87 is also called a focusing ring and has the function of converging the plasma in the processing chamber U toward the surface of the wafer Wa to improve the efficiency of plasma processing.

[0068] The mounting table 20 is held at the bottom of the chamber 11 by the support 14. A refrigerant flow path 24 is formed inside the base 18. The cooling medium such as cooling water and brine output from the refrigerator unit flows through the refrigerant inlet pipe 26a, the refrigerant flow path 24, and the refrigerant outlet pipe 26b, returns to the refrigerator unit, is controlled to a predetermined temperature, and circulates in the above path. In this way, the mounting table 20 is cooled by removing heat.

[0069] A heat transfer gas such as helium (He) supplied from a heat transfer gas supply source is supplied between the mounting surface of the electrostatic chuck 21 and the back side of the wafer Wa through the gas supply line 28. The wafer Wa is controlled to a predetermined temperature by the cooling medium circulating in the refrigerant flow path 24 and the heat transfer gas supplied to the back side of the wafer Wa.

[0070] The first high-frequency power source 32 is electrically connected to the mounting table 20 via the first matching device 33, and applies a high-frequency power HF (e.g., 40 MHz) for plasma generation of a first frequency to the mounting table 20. Furthermore, the second high-frequency power source 34 is electrically connected to the mounting table 20 via the second matching device 35, and applies a high-frequency power LF (e.g., 13.56 MHz) for bias voltage generation of a second frequency lower than the first frequency to the mounting table 20.

[0071] The first matching device 33 matches the load impedance on the plasma side with the internal impedance of the first high-frequency power source 32. The second matching device 35 matches the load impedance on the plasma side with the internal impedance of the second high-frequency power source 34.

[0072] The gas shower head 25 is installed to close the opening of the top of the chamber 11 via a cylindrical shield ring 40 provided on the outer edge thereof. The gas shower head 25 also functions as a counter electrode (upper electrode) facing the mounting table 20 (lower electrode). A top shield ring 41 is arranged on the lower surface of the shield ring 40 at the periphery of the gas shower head 25.

[0073] The gas shower head 25 has a gas inlet 45 for introducing gas. A diffusion chamber 46 is provided inside the gas shower head 25. The gas output from the gas supply source 15 is supplied to the diffusion chamber 46 through the gas inlet 45, diffused in the diffusion chamber 46, and introduced into the processing chamber U in the chamber 11 through a plurality of gas supply holes 47.

[0074] An exhaust port 55 is formed on the bottom surface of the chamber 11, and the inside of the chamber 11 is exhausted by an exhaust device 50 connected to the exhaust port 55. Thus, a predetermined vacuum level can be maintained in the chamber 11. A gate valve G is provided on the side wall of the chamber 11, and by opening and closing the gate valve G, the wafer Wa is transferred from the transfer port to the inside of the chamber 11 or outside of the chamber 11.

[0075] A cylindrical insulating ring 86 is disposed so as to cover the outer peripheral side surface of the mounting table 20 . Furthermore, a cylindrical shielding ring 89 is disposed so as to cover the outer peripheral side surface of the edge ring 87 .

[0076] A deposition guard 82 is provided along the inner wall surface of the side of the chamber 11. In addition, a deposition guard 83 is provided along the outer peripheral side surface of the mounting table 20 and the support body 14. The deposition guards 82 and 83 are configured to be freely detachable. The deposition guards 82 and 83 prevent byproducts (deposits) generated by the plasma etching process performed in the chamber 11 from adhering to the inner wall of the chamber 11.

[0077] An annular baffle plate 81 is provided in the annular exhaust passage between the deposition guards 82 and 83. An exhaust port 55 is provided in the exhaust passage 49 below the baffle plate 81.

[0078] The plasma processing device 10 is provided with a control unit 100 for controlling the operation of the entire device. The control unit 100 includes a CPU (Central Processing Unit) 105, a ROM (Read Only Memory) 110, and a RAM (Random Access Memory) 115. The CPU 105 performs a desired plasma process such as etching according to a recipe stored in a storage area such as the RAM 115. The recipe sets control information of the device for process conditions, namely, process time, pressure (gas exhaust), high frequency power or voltage, various gas flow rates, chamber temperature, temperature of a cooling medium, and the like.

[0079] When plasma processing is performed, the gate valve G is opened and closed, and the wafer Wa is carried into the chamber 11 and placed on the mounting table 20. When a DC voltage is applied from the DC power supply 22 to the chuck electrode 21a, the wafer Wa is attracted to the electrostatic chuck 21 and held.

[0080] The processing gas is supplied from the gas supply source 15 into the chamber 11. The high frequency power HF is applied to the mounting table 20 from the first high frequency power source 32, and the high frequency power LF is applied to the mounting table 20 from the second high frequency power source 34. Thus, plasma is generated in the processing chamber U, and the wafer Wa is subjected to plasma processing by the action of the plasma.

[0081] After the plasma treatment, a DC voltage opposite to that when the wafer Wa is sucked is applied from the DC power supply 22 to the chuck electrode 21a to remove the charge of the wafer Wa. Thus, the wafer Wa is peeled off the electrostatic chuck 21 and carried out of the chamber 11 through the gate valve G.

[0082] In the plasma processing apparatus 10, the components involved in the above-mentioned embodiment may also be used to constitute the components exposed to the plasma processing. For example, at least one selected from the group consisting of the edge ring 87, the shielding ring 89, the baffle 81, the gas shower head 25, the top shield ring 41, and the deposition guard 82 and the deposition guard 83 may be constituted by the above-mentioned components (sintered bodies). The plasma processing apparatus is not limited to Figure 1 The above-mentioned components can be used in various semiconductor manufacturing devices for plasma processing. The components to which the above-mentioned components are applied are not particularly limited. For example, they can also be applied to shower plates, susceptors, and the inner wall of a processing container. By using the above-mentioned sintered body in a plasma processing device, the corrosion resistance of the components of the plasma processing device 10 can be improved, and metal contamination in the etched objects such as wafers Wa and the device can be fully suppressed.

[0083] The above embodiment can also be referred to as a method of using the above sintered body as a component of a plasma processing apparatus. As mentioned above, one embodiment of the present disclosure has been described, but the present disclosure is not limited to the above embodiment.

[0084] Example

[0085] The present invention will be described in further detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[0086] (Examples 1 to 20)

[0087] [Production of sintered body]

[0088] Commercially available WC powder (average particle size: 0.6 μm) was prepared. The WC powder, raw materials for forming the secondary phase, and methanol were placed in a binderless superhard lined pot and crushed using a ball mill (rotation speed: 64 rpm) to prepare a mixed powder. The balls of the ball mill were made of a binderless superhard alloy. The mixed powder was placed in a mold of a fixed size, and a press was used to pressurize it at 100 MPa to produce a molded body. The molded body was sintered at 2200°C for 2 hours under vacuum. Here, the temperature is close to the upper limit of the vacuum sintering temperature that can be mass-produced industrially. Then, HIP treatment was performed under the conditions of 1700°C and 200 MPa to obtain the sintered bodies of Examples 1 to 20.

[0089] The composition and porosity of the sintered bodies of the respective examples are summarized in Table 1. The volume ratio of the tungsten carbide phase in Table 1 is a value obtained by subtracting the content ratio of the subphase in Table 1 from the whole (100%). The volume ratio of the tungsten carbide phase in the sintered bodies of Examples 1 to 20 was 99 volume % or more.

[0090] In the sintered bodies of Examples 1 to 6, a carbide phase (phase I), a nitride phase (phase II), or a carbonitride phase (phase III) containing elements of Groups 4 to 6 of the periodic table as constituent elements is dispersed in the tungsten carbide phase at a ratio of 1 volume % or less. In Examples 1 to 4, Cr is used as a raw material for forming the secondary phase. 3 C 2 Powder, TiC powder, TiN powder, VC powder or TaC powder. In Examples 5 and 6, ZrN powder and Ti(C·N) powder were used as raw materials for forming the subphase, respectively.

[0091] The identification of the secondary phase in each sintered body was performed using EDX (energy dispersive X-ray analysis). In addition, the volume ratio of the secondary phase was determined by scanning electron microscopy (SEM) observation of the cross section of the sintered body and image analysis based on the difference in color tone. Each sintered body was ground and then polished, and the porosity was determined from the scanning electron microscope image. As a result, the porosity of the sintered bodies of Examples 1 to 20 was less than 0.5 volume %.

[0092] In the sintered bodies of Examples 7 to 12, a composite carbide phase (phase V) having W, iron group and carbon as constituent elements is dispersed in the tungsten carbide phase. In the sintered bodies of Examples 18 to 20, a carbide phase (phase I), a nitride phase (phase II) or a carbonitride phase (phase III) having elements of Groups 4 to 6 of the periodic table as constituent elements is further dispersed.

[0093] In the sintered bodies of Examples 13 to 16, the carbon phase (phase IV) is dispersed in the tungsten carbide phase. The carbon phase contains graphite or carbon nanotubes used as a raw material.

[0094] The sintered body of Example 17 contains a carbide phase (TaC) in addition to the carbon phase. This sintered body was produced using WC powder, graphite powder and TaC powder as raw materials. The sintered bodies of Examples 18 to 20 contain a carbide phase (phase I) and a composite carbide phase (phase V).

[0095] [Table 1]

[0096]

[0097] <Evaluation of strength>

[0098] The sintered bodies of Examples 1 to 20 all have electrical conductivity, and the mechanical strength (three-point bending strength) is in the range of 700 to 1800 MPa.

[0099] (Comparative Examples 1 to 9)

[0100] Commercially available powders were used to prepare samples (sintered bodies) having the compositions shown in Table 2. Comparative Example 1 is a silicon component used as various components in a processing container of a plasma processing apparatus. Silicon components have low strength and are easily etched by plasma.

[0101] The aluminum oxide of Comparative Example 2 is more difficult to etch than silicon. However, the corrosion resistance to etching is not sufficient. Comparative Example 3 is a part of tungsten carbide (purity is 100%). Tungsten carbide is a difficult sintering body when it is a single body. The result of making a sintered body under the same conditions as the embodiment (i.e., a sintering temperature close to the industrial upper limit) is 95.6% (porosity is 4.4 volume %).

[0102] Comparative Example 4 is a superhard alloy classified as a low-cobalt superhard alloy and having a low Co content. Comparative Example 5 is a conventional superhard alloy containing Co as a binder. The sintered body was prepared in the same order as Examples 1 to 20, except that Co (20.7% by volume) was added as a binder to commercially available tungsten carbide powder and the sintering temperature was set to 1450°C. The ratio of the tungsten carbide phase in the sintered body was 79.3% by volume. The relative density of the sintered body of Comparative Example 5 was almost 100%.

[0103] Comparative Example 6 is a conventional cemented carbide containing Ni as a binder. Comparative Example 7 is a cemented carbide containing Co as a binder and added with carbides containing elements of Groups 4 to 6 of the periodic table as constituent elements.

[0104] Comparative Example 8: 2.3 volume % of carbides containing elements of Groups 4 to 6 of the periodic table as constituent elements are contained in tungsten carbide. Comparative Example 9: Y 2 O 3 Test piece of thermal spray coating.

[0105] [Table 2]

[0106]

[0107] [Evaluation as a component for plasma processing equipment]

[0108] <Plasma Etching Process>

[0109] The plasma etching of the sintered bodies (components) of each embodiment and each comparative example was evaluated in the following order. The sintered bodies were machined to produce evaluation samples with a size of φ30 mm×3 mm. The surfaces of the evaluation samples were mirror-finished. Then, as Figure 2 As shown, a part of the mirror-finished surface of the sintered body 1 was masked with a masking tape 3 made of a polyimide tape, and a plasma etching process was performed using a plasma processing device.

[0110] As a plasma processing device, a parallel plate reactive ion plasma etching device for mass production of 8-inch LSI was used. 4 The etching conditions of the gas plasma are cathode temperature 60°C, anode temperature 30°C, RF power output 1000W, chamber gas pressure 16Pa, etching time 60 minutes, gas flow rate 60sccm. Figure 2 As shown, the unmasked portion of the surface of the sintered body is etched.

[0111] <Etching depth D>

[0112] After the plasma etching treatment, the masking tape 3 was peeled off from the surface, and the step difference between the non-etched surface and the etched surface was measured using a profile measuring instrument (trade name: Surfcom2800, manufactured by TOKYO SEIMITSU CO., LTD.) to determine the etching depth D.

[0113] The etching depths D of Comparative Examples 1 and 2 were 34 μm and 3.6 μm, respectively. In contrast, the etching depths D of Examples 1 to 20 and Comparative Examples 3, 4, 8, and 9 were all within 1.5 μm. It was confirmed that Examples 1 to 20 had better corrosion resistance than Comparative Examples 1 and 2.

[0114] <Surface roughness change>

[0115] The roughness (Ra) of the non-etched surface and the etched surface of the sintered bodies of several examples and comparative examples was measured, and the change in surface roughness due to etching was found. The results are shown in Table 3. The examples have fewer irregularities than the comparative examples, which means that particle pockets can be reduced.

[0116] [Table 3]

[0117]

[0118] <Number of particles>

[0119] The number of particles after the plasma etching process was measured using a commercially available particle counter in accordance with JIS B 9921. The number of particles measured in Comparative Example 1 was approximately 100. In contrast, Examples 1 to 20 and Comparative Example 8 were in the range of 20 to 100. Comparative Examples 3 to 7 had more than 100 particles.

[0120] Regarding Comparative Example 3, it is believed that due to the high porosity, the pores on the surface become particle pockets, making it easy to hold the particles. Regarding Comparative Examples 4 to 7, they contain metal phases (Co phases or Ni phases) with a size of several μm or more. These metal phases have lower corrosion resistance to plasma than the tungsten carbide phase. Therefore, it is believed that during the plasma etching process, grooves (step differences caused by corrosion) are generated between the tungsten carbide phase and the tungsten carbide phase, which become particle pockets, making it easy to hold the particles. Regarding Comparative Example 9, due to the thermal expansion difference caused by temperature changes, fine peeling occurred on a portion of the surface.

[0121] <Metal contamination>

[0122] The plasma-etched sintered body was cleaned with a cleaning solution (hydrofluoric acid). The cleaning solution was analyzed by ICP-MS (inductively coupled plasma mass spectrometry) to evaluate metal contamination. The elements analyzed were 13 elements: Na, Mg, Al, K, Ca, Ti, Cr, Fe, Co, Ni, Cu, Zn, and W.

[0123] In the semiconductor manufacturing process, Cu, Ti, and Ca, which are harmful metal elements that are particularly prone to contaminating circuits, will be greater than 3×10 10 (atoms / cm 2 ) were judged as unqualified. For target elements other than Cu, Ti, Ca and W, for those with more than 20×10 10 (atoms / cm 2 ) was judged as unqualified. As for W, it is the same as the metal mask component and is removed by the process in the subsequent steps, so the impact is small and it is excluded from the evaluation of metal contamination.

[0124] Based on the above criteria, Examples 1 to 20 and Comparative Examples 1, 2, 3, and 9 were evaluated as acceptable. Comparative Examples 4, 5, 6, and 7 were evaluated as unacceptable because large amounts of Co or Ni were detected. Comparative Example 8 was evaluated as unacceptable because large amounts of Ti were detected.

[0125] To summarize the above results, in Examples 1 to 20, the etching depth D is small enough, and the number of observed particles is equal to or less than that of Comparative Example 1. In addition, the metal contamination is below the allowable value. In addition, all samples have conductivity, and no peeling occurs in any evaluation. On the other hand, in Comparative Example 1, there is no problem with conductivity, but due to low strength, there are difficulties in processing into the desired shape. In addition, the etching depth D is the largest, and the corrosion resistance is insufficient.

[0126] In Comparative Example 2, the etching depth D is improved compared to Comparative Example 1. However, the etching depth D is larger than that of Examples 1 to 20. In addition, since the sample has no conductivity, particles tend to be generated by electrostatic discharge.

[0127] In Comparative Example 3, even with washing, the number of particles could not be sufficiently reduced. This is considered to be the result of a large number of pores existing on the surface and inside becoming particle pockets.

[0128] Comparative Examples 4, 5, and 6 have metal phases such as Co and Ni. The metal phase is etched first to produce unevenness, which is considered to be the cause of the formation of particle pockets. In addition, the amount of Co and Ni in the metal contamination greatly exceeds the allowable range. The same is true for Comparative Example 7. In Comparative Example 8, since the volume ratio of TiC and TaC is high, it is detected that Ti and Ta exceed the allowable amount.

Claims

1. A component disposed in a chamber of a plasma processing device, comprising a tungsten carbide phase and a subphase, wherein the subphase is dispersed in the tungsten carbide phase and comprises at least one selected from the group consisting of phase I, phase II, phase III, phase IV, and phase V, The phase I is a carbide phase having at least one of the elements of the fourth group, the fifth group, and the sixth group of the periodic table other than W as a constituent element, The phase II is a nitride phase having at least one of the elements of the fourth group, the fifth group, and the sixth group of the periodic table other than W as a constituent element, The phase III is a carbonitride phase having at least one of the elements of the fourth group, the fifth group, and the sixth group of the periodic table other than W as a constituent element, The phase IV is a carbon phase, The phase V is composed of W x M y C z The composite carbide phase represented by the formula, M represents an iron group element, C represents carbon, W represents tungsten, x, y, z represent values ​​greater than 0, The content ratio of the tungsten carbide phase is 99 volume % or more, The content ratio of the subphase is 1 volume % or less, The porosity is 2 volume % or less.

2. The component according to claim 1, wherein The subphase includes the complex carbide phase of the phase III, and the complex carbide phase contains one or both of a W3Co3C phase and a W3Ni3C phase.

3. A component according to claim 1 or 2, wherein: The subphase includes at least one selected from the group consisting of phase I, phase II, and phase III, The constituent elements in the phase I, phase II, and phase III include at least one selected from the group consisting of Cr, Ta, V, and Nb.

4. A component according to any one of claims 1 to 3, wherein The secondary phase comprises the phase I, The component is composed only of the tungsten carbide phase and the carbide phase.

5. The component according to any one of claims 1 to 3, wherein The secondary phase comprises the phase IV, The component is composed only of the tungsten carbide phase and the carbon phase.

6. A component according to any one of claims 1 to 3, wherein The secondary phase comprises the phase V, The member is composed only of the tungsten carbide phase and the complex carbide phase.

7. A component according to any one of claims 1 to 3, wherein The sub-phase includes the phase I and the phase V, The member is composed only of the tungsten carbide phase, the carbide phase, and the composite carbide phase.

8. A component according to any one of claims 1 to 7, wherein The total content of Fe atoms, Co atoms, and Ni atoms is 30 to 3300 atomic ppm.

9. A component according to any one of claims 1 to 8, wherein The content of each of Fe atoms, Co atoms and Ni atoms is 1650 atomic ppm or less. 10 . A plasma processing apparatus comprising the component according to claim 1 .

11. A method for using a sintered body as a component provided in a chamber of a plasma processing device, wherein: The sintered body has a tungsten carbide phase and a subphase, wherein the subphase is dispersed in the tungsten carbide phase and includes at least one selected from the group consisting of the following phase I, phase II, phase III, phase IV, and phase V, The phase I is a carbide phase having at least one of the elements of the fourth group, the fifth group, and the sixth group of the periodic table other than W as a constituent element, The phase II is a nitride phase having at least one of the elements of the fourth group, the fifth group, and the sixth group of the periodic table other than W as a constituent element, The phase III is a carbonitride phase having at least one of the elements of the fourth group, the fifth group, and the sixth group of the periodic table other than W as a constituent element, The phase IV is a carbon phase, The phase V is composed of W x M y C z The composite carbide phase represented by the formula, M represents an iron group element, C represents carbon, W represents tungsten, x, y, z represent values ​​greater than 0, The content ratio of the tungsten carbide phase is 99 volume % or more, The content ratio of the subphase is 1 volume % or less, The porosity is 2 volume % or less.

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