JP2007194507A - Plasma generation electrode and plasma processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure a bonding status of high in-plane uniformity with regard to electric conductivity and thermal transmission of a metal base and a conductor plate that is hardly liable to be broken, in a plasma generation electrode that is provided as opposed to a substrate and is configured by the metal base and the conductor plate. <P>SOLUTION: A metal, for example, silicon is impregnated in a base metal consisting of a porous ceramics, for example, silicon carbide, and the electrode is configured by a metal based composite material having a juncture surface opposed to at least the entire surface of treated surfaces in the substrate, and the conductor plate for example CVD silicon carbide consisting of anti-plasma material melt-bonded to the junction surface of the metal based composite material with metal. In this case, the conductor plate is melt-bonded to the metal-based composite material with the metal when a metal is impregnated in the base metal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electrode for generating plasma facing a substrate to be plasma-processed and a plasma processing apparatus using the electrode.

  In the manufacturing process of semiconductors and liquid crystal devices, plasma processing using plasma is frequently used. As shown in FIG. 8, for example, a plasma processing apparatus for performing such plasma processing is a processing container 10 including a vacuum chamber. A mounting table 11 for mounting a semiconductor wafer (hereinafter referred to as a wafer) W serving as a substrate, which also serves as a lower electrode, and a number of gas supply holes 12a provided on the upper side of the mounting table 11 are provided. The shower head 12 is provided. An upper electrode 13 is provided on the lower surface of the shower head 12. A high frequency for plasma generation is applied to one of the upper electrode 13 and the mounting table 11, for example, the mounting table 11 from a high frequency power source 14. Plasma is generated in the processing space between the upper electrode 13 and the processing gas introduced into the processing container 10 from the shower head 12 is activated by the plasma, and thereby the wafer W mounted on the mounting table 11 is activated. Thus, plasma processing such as etching or film formation is performed. Note that the high frequency power from the plasma formed in the processing space reaches the upper electrode 13 and flows to the ground through the wall portion of the processing container 2 from there. Further, reference numeral 17 in FIG. 8 denotes an exhaust path for exhausting the atmosphere in the processing container 2 to the outside.

  By the way, the upper electrode 13 has a conductive plate 16 such as a silicon (Si) plate, a silicon carbide (SiC) plate or the like on the surface of a metal base (base material) 15 such as aluminum (Al) or stainless steel (SUS). It is configured to be tightly fixed to a clamp or the like. This is because the entire upper electrode 13 has a structure that is not deformed by the stress applied by the decompression of the processing atmosphere, and the part of the upper electrode 13 that is exposed to plasma has a structure that is plasma resistant and does not cause metal contamination. It is to do.

  The upper electrode 13 is heated to a high temperature by the plasma formed in the processing space. However, since Si and SiC have a smaller thermal expansion coefficient (linear expansion coefficient) than the metal base 15, the upper electrode 13 is caused by thermal expansion between them. A dimensional difference may occur, and an excessive tensile stress may be applied to the fixed portion of the conductor plate 16 to break the conductor plate 16.

  In order to avoid such a problem, in consideration of a dimensional difference between the metal base 15 and the conductor plate 16 due to thermal expansion, a screw, a clamp or the like for fixing the metal base 15 and the conductor plate 16 is a floating fixing type. It is devised so that a tensile stress is not applied to the fixing portion of the conductor plate 16 due to the thermal expansion of the base 15.

  By the way, in order to perform processing with high in-plane uniformity on the wafer W, it is required that the concentration of active species of the plasma is uniform on a surface parallel to the wafer W. It is required that the electrical and thermal state of the conductor plate 16 exposed to the surface is uniform in the plane. Therefore, it is necessary that the conductor plate 16 and the metal base 15 are in contact with each other so that electric conduction and heat transfer are performed uniformly in the surface, in other words, there is a high uniformity in the in-plane contact state. . On the other hand, since the fixing portion of the conductor plate 16 can often be installed only on the outer peripheral portion, in the case of the floating fixing type, the contact state between the metal base 15 and the conductor plate 16 varies among individuals of the upper electrode 13. Occurs. As a result, it becomes difficult to ensure high in-plane uniformity in terms of electrical continuity and heat transfer between the metal base 15 and the conductor plate 16, resulting in cracks in the conductor plate 16, process abnormalities, abnormal discharge, etc. May cause. There is also a risk that the contact surface between the metal base 15 and the conductor plate 16 is rubbed due to dimensional variation due to thermal expansion in the temperature rising / falling cycle in the plasma processing, and dust is generated from the gas supply holes 12a.

  On the other hand, in Patent Document 1, as the upper electrode 7, a center portion of porous ceramic is cut out in a trapezoidal shape when viewed in a longitudinal section, and a dielectric is fitted into the notched portion, and a metal is attached to the porous ceramic. An electrode is disclosed in which a base portion is formed by impregnating a metal base and a metal base and a dielectric are joined by the metal during the impregnation. In this technology, a dielectric is fitted into the center of the metal-ceramic composite material to attenuate the high frequency power at the center of the electrode and make the electric field strength on the lower surface of the electrode uniform. There is no suggestion about how to achieve a uniform in-plane contact state in terms of electrical conduction and heat transfer.

Japanese Patent Laying-Open No. 2005-228773 (paragraph 0032, paragraphs 0053 to 0055, FIG. 9)

  The present invention has been made in view of such circumstances, and an object thereof is to provide a metal base (in the present invention, a metal matrix composite) and a conductor plate that are provided facing a substrate and generate plasma. Provided is an electrode in which the metal plate and the conductor plate are in a bonded state with high in-plane uniformity in terms of electrical conduction and heat transfer, and a plasma processing apparatus using the electrode, in which there is no risk of destruction of the conductor plate. There is to do.

  The present invention relates to an electrode for plasma generation provided opposite to a surface to be processed of a substrate for performing plasma processing on the substrate, wherein a base material made of porous ceramics is impregnated with metal, and at least the surface to be processed of the substrate And a conductor plate made of a plasma-resistant material that is melt-bonded to the joint surface of the metal matrix composite with a metal. . In this electrode, for example, silicon carbide, silicon nitride, alumina, and aluminum nitride are used as the base material. For example, silicon or aluminum is used as the metal used for the molten metal bonding. Silicon carbide or the like is used. Among these, a preferable configuration as an electrode for generating plasma is to use silicon carbide as the base material, silicon as a metal, and silicon carbide as a conductor plate. Furthermore, it is preferable to use CVD-silicon carbide as the conductor plate. Note that CVD-silicon carbide is obtained by vaporizing and vaporizing powdered or bulk SiC on a carbon plate or the like. In the plasma generating electrode described above, it is desirable that when the base material is impregnated with metal, the conductor plate is melt-bonded to the metal matrix composite by the metal.

  Furthermore, in the electrode for generating plasma described above, a gas hole for discharging a processing gas into a processing atmosphere of the substrate is formed by a plurality of sleeves penetrating the metal matrix composite material and the conductor plate, and the metal matrix composite material, It is good also as a structure which carries out molten metal joining between each of a sleeve and a conductor board with a metal. In this case, it is desirable that when the base material is impregnated with metal, the metal matrix composite material, the sleeve, and the conductor plate are melt-bonded to each other by the metal. For example, silicon carbide or yttrium oxide is used as the sleeve.

  The plasma processing apparatus of the present invention is an airtight processing container, a mounting table provided inside the processing container, which also serves as an electrode for holding a substrate, and the mounting table facing the mounting table described above. A high frequency electric field is formed between the electrode for generating plasma described above, a gas supply unit for introducing a processing gas into the processing container, and the mounting table and the electrode facing the electrode. Plasma generating means for converting the processing gas into plasma, and processing the substrate with plasma. In the plasma processing apparatus, the processing gas introduction means has a shower head for discharging gas from a large number of holes, and the electrode functions as a shower plate on the lower surface of the shower head, and the large number of gas discharge holes. Is formed.

  In the present invention, a metal base is constituted by a metal matrix composite material in which a base material made of porous ceramics is impregnated with metal, and this metal matrix composite material is melt-bonded to a conductor plate made of a plasma resistant material to generate plasma. Therefore, the metal matrix composite and the conductor plate are uniformly joined in the plane. Therefore, since there is no occurrence of local excessive stress based on the thermal expansion dimensional difference, there is little risk of breakage of the conductor plate. Since the joint surface between the metal matrix composite and the conductor plate is filled with the molten metal, the electrical conduction and heat transfer are good, they are uniform in the surface, and individual differences between the electrodes hardly occur. As a result, plasma with high uniformity can be obtained in a plane parallel to the substrate, so that plasma processing with high in-plane uniformity can be performed on the substrate. Further, since there is no mechanical contact portion (friction portion), the friction between the two due to thermal expansion and contraction does not occur, and generation of dust can be suppressed.

  If silicon carbide is used as the material for each of the porous ceramic base material and the conductor plate, and silicon is used as the molten metal, the linear expansion at the joint surface between the metal matrix composite corresponding to the metal base and the conductor plate The difference in rate can be made substantially close to zero (there is no difference in linear expansion coefficient between silicon carbide and silicon, so it does not become zero), and the conductor plate can be reliably prevented from being damaged.

  Embodiments of the present invention will be described below. FIG. 1 is a cross-sectional view showing an RIE (Reactive Ion Etching) plasma etching apparatus which is a plasma processing apparatus to which an electrode according to an embodiment of the present invention is applied as an upper electrode. Reference numeral 2 in FIG. 1 denotes a processing container (vacuum chamber) made of, for example, aluminum. The processing container 2 includes a small-diameter cylindrical upper portion 2a and a large-diameter cylindrical lower portion 2b, and is configured to be airtight. In the processing container 2, a support table 3 that is a mounting table that horizontally supports a semiconductor wafer W (hereinafter referred to as a wafer) that is a substrate to be processed and functions as a lower electrode is provided. The support table 3 is made of aluminum, for example, and is supported by a conductor support 5 via an insulating plate 4. A focus ring 31 made of, for example, silicon (Si) is provided on the outer periphery above the support table 3. A lower portion of the support base 5 is covered with a cover 32. A baffle plate 33 is provided outside the support table 5, and is electrically connected to the processing container 2 through the baffle plate 33, the support table 5, and the cover 32. The processing container 2 is grounded.

  The top wall portion of the processing container 2 is a shower head 6 which is a gas supply unit for introducing processing gas into the processing container 2, and the lower surface of the shower head 6 is an upper electrode 7 which functions as a shower plate. It is configured. The upper electrode 7 is provided in parallel with the support table 3 functioning as a lower electrode, and a large number of gas discharge holes 71 are formed. That is, the support table 3 and the upper electrode 7 which are lower electrodes constitute a pair of parallel plate electrodes. The upper electrode 7 is grounded via the processing container 2.

  An exhaust port 21 is formed in the bottom wall of the lower part 2 b of the processing container 2, and a vacuum pump 22 is connected to the exhaust port 21. Then, by operating the vacuum pump 22, the inside of the processing container 2 can be depressurized to a predetermined degree of vacuum. On the other hand, a loading / unloading port 23 for loading / unloading the wafer W is provided on the side wall of the upper portion 2 a of the processing container 2, and the loading / unloading port 23 is opened and closed by a gate valve 24.

  The support table 3 is connected to a first high-frequency power source 26 for plasma formation and a second high-frequency power source 27 for ion attraction through matching units 28 and 25, respectively. In addition, high frequency power having a predetermined frequency is supplied from the second high frequency power supply 27 to the support table 3. The second high frequency power supply 27 supplies high frequency power lower than the frequency of the first high frequency power supply 26.

  An electrostatic chuck 34 for electrostatically attracting and holding the wafer W is provided on the surface of the support table 3. The electrostatic chuck 34 is configured by interposing an electrode 34a between insulators 34b, and a DC power source 35 is connected to the electrode 34a. When a voltage is applied to the electrode 34a from the power source 35, the wafer W is attracted and held by electrostatic force, for example, Coulomb force.

  In addition, a cooling chamber 36 is provided inside the support table 3. In this cooling chamber 36, a refrigerant is introduced through a refrigerant introduction pipe 36a, discharged from a refrigerant discharge pipe 36b, and circulated. Is transferred to the wafer W via the support table 3, whereby the processing surface of the wafer W is controlled to a desired temperature.

  Further, even if the inside of the processing container 2 is evacuated by the vacuum pump 22 and kept in a vacuum, the cooling gas is supplied by the gas introduction mechanism 37 so that the wafer W can be effectively cooled by the refrigerant circulated in the cooling chamber 36. It is introduced between the front surface of the electrostatic chuck 34 and the back surface of the wafer W via the gas supply line 38. By introducing the cooling gas in this way, the cooling heat of the refrigerant is effectively transmitted to the wafer W, and the cooling efficiency of the wafer W can be increased.

  The shower head 6 is provided with a gas inlet 72 at an upper portion thereof, and a space 73 for gas diffusion is formed therein. A gas supply pipe 74 is connected to the gas introduction port 72, and a processing gas supply system 75 for supplying a processing gas is connected to the other end of the gas supply pipe 74.

  On the other hand, around the upper part 2a of the processing container 2, two multipole ring magnets 25a and 25b are arranged with the loading / unloading port 23 interposed therebetween. The multi-pole ring magnets 25a and 25b are configured by attaching a plurality of anisotropic segment columnar magnets to a casing of a ring-shaped magnetic body, and the directions of a plurality of adjacent segment columnar magnets are opposite to each other. It is arranged to be. As a result, magnetic field lines are formed between adjacent segment magnets, and a magnetic field is formed only in the peripheral portion of the processing space between the upper and lower electrodes, and has an action of confining plasma in the processing space.

  Next, the configuration of the upper electrode 7 will be described in detail. The upper electrode 7 has a circular shape through a bonding layer 81 on the lower surface of a metal matrix composite material 8 in which a cylindrical base material made of porous ceramics is impregnated with metal, as shown in an enlarged view in FIG. The conductive plate 82 is formed. Since the upper electrode 7 is a part that emits electric lines of force for converting the processing gas into plasma, in order to generate plasma with high in-plane uniformity on the surface of the wafer W, the joint surface of the metal matrix composite 8 is used. In other words, the size of the conductive plate 82, that is, the size of the conductor plate 82, needs to be the same as or larger than the surface of the wafer W to be processed.

  A method for manufacturing the upper electrode 7 will be specifically described with reference to FIGS. First, a conductive plate 82 made of CVD-silicon carbide (SiC) is laminated on a porous base material 9 made of silicon carbide (SiC) (FIG. 3A). Next, molten metal (molten metal) made of silicon (Si) is pressurized with a gas pressure or the like to impregnate the base material 9 to form a metal matrix composite 8 (FIG. 3B). The molten metal continues to be pressurized after the molten metal reaches the metal matrix composite 8, and the surface (joint surface) of the metal matrix composite 8 and the conductor by the molten metal oozing out from the surface of the metal matrix composite 8. The surface of the plate 82 is bonded to each other to form a bonding layer 81 (FIG. 3C). Thereafter, the upper electrode 7 is obtained by cooling (FIG. 3D). In this manufacturing method, the base metal 9 is impregnated by pressurization with gas pressure or the like (pressure infiltration method), but is not limited to this method, and a capillary phenomenon generated in the pores of the base material 9 is used. Then, the base metal 9 may be impregnated with molten metal (natural penetration method). The metal matrix composite 8 in which the base material 9 is impregnated with the molten metal is used as a metal base because it has the same conductivity as the metal and retains the strength of the base material 9.

  In this example, the upper electrode 7 (electrode for generating plasma) is configured by using silicon carbide as the base material 9, CVD-silicon carbide as the conductive plate 82, and silicon as the molten metal. The combination of materials is not limited to this. Other combinations will be described later.

  Then, an example of the formation method of the gas discharge hole 71 formed in the upper electrode 7 is demonstrated. In this method, the upper electrode 7 is cut with a cutting tool such as a drill to form a gas discharge hole 71 having a diameter of 0.5 to 1 mm, for example, but the metal matrix composite material 8 and the bonding layer constituting the upper electrode 7 Since 81 and the conductor plate 82 have different hardnesses, cutting is performed while replacing with a drill suitable for cutting the material for each material. That is, the metal matrix composite material 8, the bonding layer 81, the conductor plate 82, and the holes are opened in this order, and the gas discharge holes 71 are formed in the upper electrode 7. A method for forming the gas discharge holes 71 in the upper electrode 7 other than this method will be described later.

  Next, a process for etching a predetermined film formed on the surface of the wafer W with plasma using the plasma etching apparatus configured as described above will be described. First, the gate valve 24 is opened, and the wafer W is loaded into the processing container 2 from the loading / unloading port 23 and placed on the support table 3. Then, the processing chamber 2 is evacuated by the vacuum pump 22 through the exhaust port 21. Exhaust to a degree.

  Then, a processing gas such as fluorine (F) from the processing gas supply system 75 reaches the space 73 of the shower head 6 through the gas supply pipe 74 and the gas introduction port 72, and is discharged from the gas discharge hole 71. The gas pressure is set to, for example, 13 to 1333 Pa (100 mTorr to 10 Torr), and in this state, for example, high frequency power of 100 MHz is supplied from the first high frequency power supply 26 to the support table 3. This high frequency flows from the support table 3 to the processing container 2 via the conductor plate 82 of the upper electrode 7 and the metal matrix composite 8 and falls to the ground, thus forming a high frequency electric field in the processing atmosphere.

  Further, from the second high frequency power supply 27, for example, high frequency power of 3.2 MHz is supplied in order to control ion energy of plasma. At this time, the wafer W is attracted and held on the electrostatic chuck 34 by, for example, Coulomb force when a predetermined voltage is applied from the DC power source 35 to the electrode 34a of the electrostatic chuck 34, and the upper electrode 7 and the lower electrode are used. A high frequency electric field is formed between the support table 3 and the support table 3. Further, since a horizontal magnetic field is formed between the shower head 6 and the support table 3 by the dipole ring magnets 25a and 25b, an orthogonal electromagnetic field is formed in the processing space between the electrodes on which the wafer W exists, thereby Magnetron discharge is formed by the drift of the generated electrons. The processing gas is turned into plasma by the magnetron discharge, and a predetermined film formed on the surface of the wafer W is etched by the plasma.

  According to the above-described embodiment, the metal matrix composite 8 in which the base material 9 made of silicon carbide, which is porous ceramics, is impregnated with silicon, which is a metal (in the present invention, the semiconductor is also handled as metal) is used to form a metal. Since the base is constituted and the metal matrix composite material 8 is melt-bonded to a conductor plate 82 made of CVD-silicon carbide which is a plasma-resistant material, the upper electrode 7 (electrode for generating plasma) is constituted. The metal matrix composite 8 and the conductor plate 82 are uniformly joined in the plane. Therefore, unlike the case where the peripheral edge of the conductor plate 82 is screwed, there is no occurrence of local excessive stress based on the thermal expansion dimensional difference, and therefore there is little risk of the conductor plate 82 being destroyed. And since the joining surface of the metal matrix composite 8 and the conductor plate 82 is filled with molten metal (silicon), heat transfer by high-frequency electrical conduction and heat input from plasma is good as shown in FIG. In addition, they are uniform in the plane, and individual differences in the upper electrode 7 are less likely to occur. As a result, the potential and temperature of the conductor plate 82 have high uniformity in the plane, and plasma with high uniformity is obtained in the plane parallel to the wafer W placed on the support table 3 as the lower electrode. Therefore, plasma processing with high in-plane uniformity can be performed on the wafer W. Further, since there is no mechanical contact portion (friction portion), the friction between the two due to thermal expansion and contraction does not occur, and generation of dust can be suppressed.

  If silicon carbide is used as the base material 9 and the conductor plate 82 which are porous ceramics, and silicon is used as the molten metal, the linear expansion at the joint surface between the metal matrix composite 8 corresponding to the metal base and the conductor plate 82 is achieved. The difference in rate can be made close to zero, and damage to the conductor plate can be reliably prevented.

  In the above-described embodiment, as the base material 9, for example, silicon nitride (Si3N4), alumina (Al2O3), aluminum nitride (AlN) or the like may be used in addition to silicon carbide. In addition to silicon carbide, for example, silicon (Si) or the like may be used as the conductor plate 82. In addition to silicon, the molten metal impregnated in the base material 9 may be aluminum (Al), for example.

  Further, as a method of forming the gas discharge hole 71 in the upper electrode 7, as shown in FIG. 5, a hole 83 penetrating the base material 9 and the conductor plate 82 is formed in advance before the molten metal bonding (FIG. 5 ( a)) The base metal 9 and the conductor plate 82 are melt-bonded to close the hole 83 with the molten metal 84 (FIG. 5B), and then the molten metal 84 blocking the hole 83 is cut with a drill. Thus, the gas discharge hole 71 may be formed in the molten metal 84 (FIG. 5C).

Furthermore, as shown in FIG. 6, a hole penetrating the base material 9 and the conductor plate 82 is formed in advance before performing the molten metal bonding, and a bar 85 is inserted into this hole (FIG. 6A), In this state, the base metal 9, the conductor plate 82, and the bar 85 are joined by the molten metal impregnated in the base material 9 by performing the molten metal joining (FIG. 6B), and the metal matrix composite material 8 and the conductor plate. A gas discharge hole 71 having a sleeve structure may be formed by cutting the bar 85 joined to 82 using a cutting tool such as a drill (FIG. 6C). In this case, the rod (sleeve) 85 is preferably a brittle material such as silicon carbide (SiC) and yttrium oxide (Y2O3).
FIG. 7 shows a result of the present inventors examining a preferable combination of materials for the upper electrode 7 in the above-described base material 9, conductor plate 82 and molten metal materials. Also, A of the gas hole processing method shown in FIG. 7 is to open a hole while changing the drill of the metal matrix composite material 8, the bonding layer 81, and the conductor plate 82 in this order as described in the previous embodiment. This is a method of forming the gas discharge holes 71 in the upper electrode 7, B is the gas hole processing method described with reference to FIG. 5, and C is the gas hole processing method described with reference to FIG. 6. In FIG. 7, each of the base material 9, the conductor plate 82, and the molten metal constituting the upper electrode 7 is marked with a circle corresponding to the selected material. The combination of the base material 9, the conductor plate 82, and the molten metal constituting the upper electrode 7 is indicated by P1 to P12. For example, in P2, SiC is selected as the base material 8, Si is selected as the conductive plate 82, and Al is selected as the molten metal. Yes. In FIG. 7, in the part exposed to plasma, the combination is determined from the intention of avoiding aluminum as much as possible from the viewpoint of preventing metal contamination. However, when silicon is used as the conductor plate 82, a material having a lower melting point than silicon. Therefore, aluminum is used as the molten metal. In this case, since aluminum is used as the molten metal, it can be said that there is little concern about metal contamination. Examples of the material of the sleeve 85 include Al2O3, AlN, SiO2, SiN, Y2O3, and SiC. However, Al2O3 and AlN cannot be used from the viewpoint of preventing metal contamination, and SiO2 has a problem in strength. SiN is very expensive. For this reason, it can be said that Y2O3 and SiC are preferable from the viewpoint of avoiding the aluminum-containing material, having high strength and low cost.

  Further, when the upper electrode 7 is manufactured, it is preferable to select the material of the base material 9 and the conductor plate 82 so that the dimensional difference due to thermal expansion between the base material 9 and the conductor plate 82 is suppressed within 30%. .

  The substrate in the present invention is not limited to a wafer as in the above-described embodiment, and may be a glass substrate for a flat panel used in a liquid crystal display or a plasma display, or a ceramic substrate. .

It is sectional drawing which shows the RIE plasma etching apparatus which applied the electrode which concerns on one embodiment of this invention as an upper electrode. It is sectional drawing which expands and shows the upper electrode of the apparatus of FIG. It is explanatory drawing explaining the method to join a composite material and a conductor board with an impregnation metal, when impregnating a base material with a metal and forming a composite material. It is explanatory drawing which shows the mode of the upper electrode of the apparatus of FIG. It is explanatory drawing explaining the other example of the formation method of the gas discharge hole formed in an upper electrode. It is explanatory drawing explaining the other example of the formation method of the gas discharge hole formed in an upper electrode. 2 is a table showing combinations of materials of a base material, a conductor plate, and a molten metal in the upper electrode of the apparatus of FIG. 1. It is a schematic sectional drawing which shows the conventional plasma processing apparatus.

Explanation of symbols

W Wafer 2 Processing vessel 3 Support table 4 Insulating plate 5 Support base 6 Shower head 7 Upper electrode 71 Gas discharge hole 8 Metal matrix composite material 81 Joining layer 82 Conductor plate 83 Hole 84 Molten metal 85 Bar material (sleeve)
9 Base material

Claims (11)

In the electrode for plasma generation provided to face the processing surface of the substrate in order to perform plasma processing on the substrate,
A metal matrix composite material comprising a base material made of porous ceramics and impregnated with metal, and having a bonding surface facing at least the entire surface to be processed of the substrate;
An electrode for plasma generation, comprising: a conductor plate made of a plasma-resistant material joined to a joining surface of the metal matrix composite material by a molten metal with a metal.   2. The electrode for generating plasma according to claim 1, wherein the base material is selected from silicon carbide, silicon nitride, alumina, and aluminum nitride.   The electrode for generating plasma according to claim 1, wherein the metal used for the molten metal bonding is silicon or aluminum.   The electrode for plasma generation according to claim 1, wherein the conductor plate is silicon or silicon carbide.   2. The electrode for generating plasma according to claim 1, wherein the base material is silicon carbide, the metal used for molten metal bonding is silicon, and the conductor plate is silicon carbide.   6. The electrode for generating plasma according to claim 5, wherein the conductor plate is CVD-silicon carbide.   The electrode for plasma generation according to any one of claims 1 to 6, wherein when the base material is impregnated with a metal, the conductor plate is melt-bonded to the metal matrix composite by the metal. Gas holes for discharging a processing gas into the processing atmosphere of the substrate are formed by a large number of sleeves penetrating the metal matrix composite and the conductor plate,
The electrode for generating plasma according to any one of claims 1 to 6, wherein the metal matrix composite material, the sleeve, and the conductor plate are melt-bonded by metal.   9. The electrode for generating plasma according to claim 8, wherein when the base material is impregnated with metal, the metal matrix composite material, the sleeve, and the conductor plate are each melt-bonded by the metal.   The electrode for generating plasma according to claim 8 or 9, wherein the sleeve is made of silicon carbide or yttrium oxide. An airtight processing container, a mounting table provided inside the processing container and also serving as an electrode for holding a substrate, and a processing table provided inside the processing container so as to face the mounting table. 10. A high-frequency electric field is formed between the electrode according to any one of 10, a gas supply unit for introducing a processing gas into the processing container, the mounting table and the electrode facing the processing table, and the processing. And a plasma generating means for converting the gas into plasma, and processing the substrate with plasma.

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