JP2008028087A - Plasma etching electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma etching electrode which consists of a tabular member and a support member for supporting the tabular member, wherein the tabular member and the support member are firmly fixed to each other and the tabular member which is a consumable part can be exchanged easily. <P>SOLUTION: The plasma etching electrode consists of the tabular member 1 and the annular support member 2 for supporting the tabular member 1. On the outer circumferential surface of the tabular member, male screws are formed; and on the inner circumferential surface of an end part of a stepped structure of the ring-shaped support member, female screws are formed. By making the male screws of the tabular member and the female screws of the annular member engage with each other, the tabular member and the annular member are joined together to form the plasma etching electrode. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plasma etching electrode used when etching the surface of a semiconductor wafer or the like with plasma.

  In the manufacturing process of a semiconductor integrated circuit, the surface of the wafer is etched for the purpose of forming elements on a semiconductor wafer. With the progress of densification technology, the importance of plasma etching technology capable of forming a fine pattern on a wafer with high accuracy is increasing.

  FIG. 9 shows a conceptual diagram of a plasma etching apparatus. An upper electrode (plasma etching electrode) and a lower electrode are provided in the vacuum container at intervals, and a wafer is placed on the lower electrode as a material to be processed. The etching gas passes through a gas jet port provided in the upper electrode and flows toward the wafer, and plasma is formed by a high frequency power applied between the upper electrode and the lower electrode by a high frequency power source. The wafer is etched by this plasma, and a predetermined pattern is formed on the wafer surface.

  The upper electrode has a complicated shape due to the structure of the device, and most of the material is glassy carbon, silicon, or silicon carbide (SiC). It becomes very expensive. In addition, since the consumption occurs exclusively in the portion in contact with the plasma, and the other portions are less consumed, it is preferable to have a structure in which only the heavily consumed portion is replaced.

  Therefore, as a plasma etching electrode (upper electrode), a flat member (electrode plate) made of silicon or the like is joined to a support member (support ring, support plate, pedestal) made of metal or graphite as shown in FIG. Has been used. In such a configuration, since the flat plate member is etched and consumed exclusively by plasma, the flat plate member is consumed to some extent, and etching characteristics (etching rate, etching rate uniformity within the wafer surface, number of particles on the wafer) Etc.), the use of the plasma etching electrode is stopped, and only the flat plate member is replaced with a new material.

For joining the support member and the electrode plate, metal brazing using indium or silver brazing is usually performed. The metal brazing is not particularly problematic as a conductive and heat conductive material.
However, with the improvement of the performance of the plasma etching apparatus, the temperature at which the wafer is processed is increased. However, in the conventional joining by metal brazing such as indium, although the adhesive strength is, the heat-resistant temperature is low, for example, Since the melting point of indium is 156 ° C., there is a concern that if the bonding surface exceeds this temperature, it may be peeled off, or a pretreatment in the manufacturing process, for example, a base layer such as sputtering of a metal film There is a problem that the processing and the high temperature work are complicated, and as a result, the workability and the cost for the processing are increased.

In addition, the brazing material itself may cause contamination of the silicon wafer. Therefore, good etching characteristics in dry etching cannot be obtained, and there is a problem that the yield of semiconductor devices, that is, silicon wafers is deteriorated.
Patent Document 1 proposes that a support ring made of graphite is used, and an adhesive containing an epoxy resin containing a polycarbodiimide resin and carbon powder is used as an adhesive. According to this method, the bonding between the electrode plate and the pedestal is made strong even at a high temperature, and good thermal conductivity and conductivity are obtained between the electrode plate and the pedestal. However, since this method uses an adhesive, peeling may occur under temperature conditions exceeding the heat resistance temperature of the adhesive.

Patent Document 2 discloses that an electrode is damaged by using an elastomer material (polyimide, polyketone, silicone, etc.) that has a conductive filler in the bonding between the electrode and the support ring and can be used in a plasma environment exceeding 160 ° C. It is described that the possibility is reduced and the peeling of the electrode from the support ring due to thermal fatigue is reduced.
However, this elastomer material is not sufficient in terms of heat resistance.
Patent Document 3 describes that a silicon electrode and an electrode outer peripheral portion made of another material are screwed with bolts as shown in FIG.
However, this method increases the number of parts, which complicates the screwing operation and leads to an increase in cost. Also, due to the difference in thermal expansion coefficient between the electrode, the support ring and the screw, the screwing part tends to be distorted during high temperature use. There is a problem.

  Patent Document 4 describes a plasma etching electrode having a structure shown in FIG. 12. An electrode plate is inserted into a ring hole of a support ring in a state where the support ring is heated and expanded, and then the support ring is cooled. It is described that the electrode plate 2 is shrink-fitted by contraction. Further, the flange in FIG. 12 is arbitrarily provided, and a recess is provided in the ring wall of the support ring, and the flange is shrink-fitted into the recess. However, this apparatus joins an electrode plate and a support ring by a method called shrink fitting, and a heating device and a tool for shrink fitting are necessary when replacing the electrode plate.

JP 2004-6561 A JP 2003-133296 A Japanese Patent Laid-Open No. 11-162940 International Publication No. 01/48791 Pamphlet

  An object of the present invention is to provide an electrode for plasma etching composed of a flat plate member and a support member that supports the flat plate member. The flat plate member and the support member are firmly fixed, and the flat plate member that is a consumable part can be replaced. An object of the present invention is to provide an easy electrode for plasma etching.

As a result of earnest research on the electrode of the plasma etching apparatus optimal for overcoming the problems of the prior art, the present inventors have provided a male screw structure on the outer peripheral surface of the electrode plate, and the inner peripheral surface of the support member. The present invention has been completed by finding that the above-mentioned problems can be solved by providing a female screw structure on the screw and directly screwing the two into the screw portion.
That is, the present invention is a plasma etching electrode as described below.

(1) In a plasma etching electrode comprising a flat plate member and a ring-shaped support member that supports the flat plate member, a male screw is formed on the outer peripheral surface of the flat plate member, and a female screw is formed on the inner peripheral surface of the end of the ring-shaped support member. A plasma etching electrode in which a screw is formed and a flat plate member and a ring-shaped support member are joined by screwing a male screw of a flat plate member and a female screw of a ring member.
(2) The plasma etching electrode according to (1), wherein an end portion of the ring-shaped support member has a step structure, and an internal thread is formed on an inner peripheral surface of the step structure portion.
(3) The plasma etching electrode as described in (1) above, wherein the outer peripheral surface of the flat plate member has a step structure, and a male screw is formed on the outer peripheral surface of the step structure portion.
(4) The end portion of the ring-shaped support member has a step structure, and an internal thread is formed on the inner peripheral surface of the step structure portion, and the outer peripheral surface of the flat plate member has a step structure. The plasma etching electrode according to (1), wherein a male screw is formed on the outer peripheral surface of the stepped structure.
(5) In a plasma etching electrode comprising a flat plate member and a flat plate support member that supports the flat plate member, a male screw is formed on the outer peripheral surface of the flat plate member, and the flat plate support member has a recess at the center thereof. The plasma is formed by forming a female screw on the inner peripheral surface of the recess and joining the flat plate member and the flat plate support member by screwing the male screw of the flat plate member and the female screw of the flat plate support member. Etching electrode.
(6) The plasma etching electrode as described in (1) above, wherein the outer peripheral surface of the flat plate member has a step structure, and a male screw is formed on the outer peripheral surface of the step structure portion.

  The plasma etching electrode of the present invention is composed of only a flat plate member (hereinafter also referred to as “electrode plate”) and a support member, and has a small number of parts, which is advantageous in terms of cost. In addition, the plasma etching electrode of the present invention can replace only the flat plate material or only the support member, and since the flat plate member and the support member are joined by screws, the replacement can be easily performed. In addition, peeling due to thermal shock does not occur.

Hereinafter, the plasma etching electrode of the present invention will be described in detail.
The plasma etching electrode of the present invention comprises a flat plate member (electrode plate) and a support member that supports the flat plate member.
Below, the material of a plasma etching electrode is described first.
The size of the electrode plate for plasma etching of the present invention is not particularly limited. For example, when the object of etching is a silicon wafer and the size of the silicon wafer is 6 to 12 inches, the outer diameter is 200 to 400 mm, the thickness is 5 mm or more, and particularly preferably 10 mm or more.
Although the size of the gas ejection holes for ejecting the etching gas varies depending on the etching conditions and the like, the hole diameter is preferably 0.3 to 2 mm, and the number of holes is preferably 100 to 3000.

  In general, in a plasma etching electrode, a cooling plate is attached to the back surface of an electrode plate in order to remove heat generated in the electrode and keep the temperature of the electrode appropriately constant. In the present invention, this cooling plate may or may not be used. As the cooling plate, there is no fear of impurity contamination of the silicon wafer in the etching process, and the cooling plate is used on the upper part and is usually made of aluminum having a high thermal conductivity.

As a material for the electrode plate and the supporting member constituting the plasma electrode, silicon, graphite, glassy carbon, pyrographite, aluminum, silicon carbide, quartz, or the like is preferably used. Pyrocarbon and glassy carbon can also be used by being coated with graphite or the like.
Among the above materials, single crystal silicon is particularly preferable as an electrode material, and it is desirable to use single crystal silicon having high purity and high density. Examples of such silicon include P-type single crystal silicon whose dopant (doping agent) is shelf element (B), and the crystal orientation is <100>. The resistivity is generally in the range of 1 μΩ · cm to 100 Ω · cm.

Graphite is also not particularly limited, but it is desirable to use graphite having high thermal conductivity and high purity without fear of impurity contamination during silicon wafer etching. Examples of such graphite include those of semiconductor grade. For example, commercially available products include CX-2123, CX-2114, and CX-2206 manufactured by Le Carbon, and EGF- manufactured by Toyo Tanso. 262, EGF-264, and the like.
Further, it is desirable that the surface of graphite is coated with glassy carbon. The glassy carbon to be coated has a thickness of usually 2 to 3 μm, and the coating method is not particularly limited, and can be appropriately selected from conventionally used methods. For example, gloss treatment However, an impregnation process may be used. In particular, a method of forming a glassy carbon coating by coating graphite with a certain resin, such as polycarbodiimide, a phenol resin, or the like, and firing it is preferable.
This glassy carbon acts as a graphite covering layer, suppresses the generation of graphite dust, and contributes to corrosion resistance and the like. In particular, during dry etching, the generation of gas from the graphite in the plasma atmosphere is suppressed, and the substance forming the oxide layer on the surface of the graphite is peeled off to prevent the possibility of particles adhering to the wafer.

  Although aluminum is not particularly limited, it is usually made of a 5000 series aluminum alloy or a 6000 series aluminum alloy specified by JIS standard, which has been untreated or hard anodized (anodized). Is done. Further, these 5000 series alloys and the above 6000 series alloys contain many impurity elements, and these impurity elements remain in the hard anodized film after the hard anodized treatment. At the same time, the impurity elements remaining in the hard anodized film are scattered on the silicon wafer, which has an adverse effect such as metal marine dyeing. Therefore, aluminum having high purity of 3N or higher, high purity aluminum and 0.2-1. An aluminum alloy containing Owt% silicon and 0.35 to 2.5wt% magnesium can also be used as a material.

  Silicon carbide (silicon carbide) is not particularly limited, and may be produced by various methods. For example, silicon carbide is sintered, carbon and silicon are reactively sintered, and carbon is converted into silicon carbide. What was converted, what was produced by chemical vapor deposition (CVD), physical vapor deposition (pvD), etc. can be used. In addition, as this silicon carbide material, the thing with few metal impurities is preferable.

Pyrocarbon (pyrolytic graphite) is excellent in oxidation resistance and abrasion resistance and generates very little dust, and can therefore be used for an electrode plate. It can also be used as a graphite material in which the surface of the graphite material is coated with a pyrocarbon having a thickness of several tens of microns by a special CVD method. The pyrocarbon can be formed by various chemical vapor deposition methods. However, usually, the graphite base material is heated, and a hydrocarbon gas such as methane, propane or the like is allowed to react with the graphite base material at a high temperature (2000 ° C. to 2200 ° C.), and pyrocarbon is formed on the surface of the graphite base material. Depends on the method used In this case, hydrogen gas is suitable for adjusting the temperature of the hydrocarbon gas or for the carrier gas. The reaction is carried out under normal pressure or reduced pressure, but it is preferably carried out under reduced pressure in order to obtain film uniformity and smoothness, and is preferably carried out at 300 Torr or less.
As described above, in order to independently take out the pyrocarbon laminated on the graphite base material, the whole may be returned to room temperature. The thermal expansion coefficients of the graphite base material and the pyrocarbon are 3 to 5 × 10 ⁻⁶ / ° C. and 1.7 × 10 ⁻⁶ / ° C., respectively. It can be done.

  Of course, the pyrocarbon itself formed as described above has high purity, but when it is used as a pyrocarbon simple electrode plate by laminating it thickly on the graphite base, In some cases, impurities such as iron, nickel, cobalt, and vanadium are mixed, and these may remain on the pyrocarbon side. If these impurities remain, the surface of the wafer to be plasma-etched may be contaminated and must be removed. However, since these were contained in the graphite substrate, pyrocarbon graphite It can be easily removed by removing the surface on which the substrate is in contact by polishing or the like.

  As described above, the glassy carbon is also referred to as non-graphitizable carbon or hard carbon, and may be of any raw material and manufacturing method as long as it is generated by solid-phase carbonization of an organic substance, There is no particular limitation. Glassy carbon is a hard carbonaceous material that resembles a macroscopically non-porous three-dimensional network structure obtained by carbonizing a thermosetting resin, etc., and has high strength, chemical stability, and gas impermeability. Excellent wear resistance, self-lubricating properties, fastness, low impurities, etc. Especially, it is an advantage that minute particles that cause contamination of the wafer during the plasma etching process are difficult to peel off from the structure. There is.

  As a starting material for glassy carbon, a thermosetting resin is usually used. Polycarbodiimide resin, phenol resin, epoxy resin, furan resin, polyimide resin, polyamide resin, polyamideimide resin, melamine resin, polyacrylonitrile resin, Examples thereof include saturated polyester resins, mixtures thereof, and possible copolymers. Phenol resins, furan resins, and furfural phenol copolymers that are usually used as raw materials for glassy carbon are preferred. Moreover, what has a function of a thermosetting resin by mix | blending a hardening | curing agent with a thermoplastic resin can also be used, for example, what mix | blended hexamethylenetetramine as a hardening | curing agent with a novolak-type phenol resin etc. can be used. .

Next, embodiments of the plasma etching electrode of the present invention will be described.
FIG. 1 shows one embodiment of the plasma etching electrode of the present invention.
As shown in FIG. 1 (b), the plasma etching electrode is composed of a flat plate member (electrode plate 1 and ring-shaped support member 2. The electrode plate 1 has a structure as shown in FIG. 1 (a). A large number of through holes (gas ejection holes) for blowing an etching gas are provided. When etching is performed, the etching gas is converted into plasma when passing through the gas ejection holes of the electrode plate 1, and among these, the reactivity is obtained. Etching is performed while ions are directed to the surface of an object to be etched such as a silicon wafer placed on the lower electrode.
Further, as shown in FIG. 1C, a male screw is threaded on the outer peripheral surface of the electrode plate 1, and a female screw is threaded on the inner peripheral surface of the end portion of the ring-shaped support member 2. .
When the electrode plate is consumed, the electrode plate can be easily replaced by removing the consumed electrode plate and screwing the new electrode plate to the support member.
Since the flat plate member and the support member are joined by screws, it is necessary to use materials having a small difference in thermal expansion as the respective materials in order to prevent the occurrence of thermal distortion during high temperature use.
As such a combination of materials, the same material such as silicon and silicon is preferable. However, in consideration of material cost and yield, a combination of silicon and graphite having a close thermal expansion coefficient may be used.

  In the example shown in FIG. 2, a male screw is threaded on the outer peripheral surface of the electrode plate 1, the end of the ring-shaped support member has a step structure, and a female screw is threaded on the inner peripheral wall of the step structure portion. Both are screwed together to join.

  In the example shown in FIG. 3, a step structure is provided on one side in the thickness direction of the electrode plate 1, a male screw is threaded on the outer peripheral surface of the step structure, and the inner peripheral surface of the end portion of the ring-shaped support member A female screw is screwed into the two, and both are screwed together to be joined.

  In the example shown in FIG. 4, one end in the thickness direction of the electrode plate 1 has a step structure, and a male screw is threaded on the outer peripheral surface of the small diameter portion of the step structure, and the end of the ring-shaped support member The portion has a step structure, and a female screw is screwed into the inner peripheral wall of the step structure portion so that both are screwed together and joined.

  In the example shown in FIG. 5, one end in the thickness direction of the electrode plate 1 has a step structure, and a male screw is threaded on the outer peripheral surface of the large diameter portion of the step structure portion, and the ring-shaped support member The end portion has a two-step structure, and a female screw is threaded on the inner peripheral surface of the outer step structure portion, and both are screwed together to be joined.

  In the example shown in FIG. 6, a male screw is threaded on the outer peripheral surface of the electrode plate 1, the support member is formed into a flat plate shape, a circular concave portion is provided in the central portion of the flat plate, and the inner peripheral surface of the concave portion is provided. The female screw is threaded and both are screwed together to join.

  In the example shown in FIG. 7, one end in the thickness direction of the electrode plate 1 has a step structure, a male screw is threaded on the outer peripheral surface of the small diameter portion of the step structure portion, and the support member has a flat plate shape. A circular concave portion is provided at the center of the flat plate, and a female screw is threaded on the inner peripheral surface of the concave portion so that both are screwed together and joined.

In the example shown in FIG. 8, both the electrode plate 1 and the support member 2 are made flat, and a male screw is threaded on the outer peripheral surface of the electrode plate 1, and a female screw is threaded on the inner peripheral surface of the support member 2. And screwed together. In the case shown in FIG. 8, the outer peripheral portion of the flat plate becomes the attachment portion without providing the enlarged diameter portion for attachment at one end of the ring-shaped support member as shown in FIG. The member 2 can be easily molded and attached.
2 and 5, the support member can be shaped like a flat plate, and the outer peripheral portion of the flat plate can be used as a mounting portion.

In the case of the structure shown in FIGS. 3, 4, and 7, the screwing operation by the tightening jig can be facilitated by making the outer periphery of the electrode plate 1 polygonal.
The screws provided on the outer peripheral surface of the flat plate material need not be provided over the entire length in the thickness direction, and may be provided for a part.
Further, in order to ensure the heat conduction characteristics and conductivity between the flat plate member and the support member, the rubber member, the metal sheet, the O-ring, the paste-like material, etc., to which those functions are given are used. It may be sandwiched between.

  Hereinafter, the present invention will be described in more detail by way of examples with reference to the drawings. However, the present invention is not particularly limited to these examples.

[Example 1]
The plasma etching electrode manufactured in this example has the shape shown in FIG.
First, a silicon original plate that is single crystal silicon (P-type (B-doped), crystal orientation <100>, electrical resistivity 15 Ω · cm) is processed to have a diameter of 204.3 mm and a thickness of 6.35 mm. The shape of the ejection holes (φ0.8 mm) was 3,200, and external threads (valley diameter 203.2 mm, pitch 0.7 mm) were threaded on the outer peripheral surface. This was used as the flat plate member of the electrode.
Next, E + 25 graphite manufactured by Le Carbon Co., Ltd. is processed into a ring shape with an outer diameter of 223.5 mm, an inner diameter of 203.2 mm, and a thickness of 25.4 mm, and a shape that is provided with a collar portion that is fixed to the device at the end, A female screw corresponding to the male screw was threaded on the inner peripheral surface of the ring wall end opposite to the side provided with the collar portion. This was used as an electrode support member.
The lithographic member obtained above and the support member were screwed together to produce a plasma etching electrode, which was subjected to actual wafer etching as an electrode member of a silicon wafer dry etching apparatus.
As a dry etching apparatus, Exel 4250 manufactured by LAM RESEARCH was used.
The plasma etching electrode was set in a dry etching apparatus, and reaction gas: trifluoride methane (CHF ₃ ) and tetrafluoromethane (CF ₄ ), carrier gas: argon (Ar), gas pressure in the reaction chamber: 70 mTorr, RF Oxide film etching was performed on a silicon wafer having a diameter of 8 inches under the condition of power: 4000 W.
As an evaluation item, the state of the joint (the state of the joint when the wafer was etched at 4000 W for 8 minutes and then cooled for 2 minutes was repeated 2500 times) was evaluated.
The evaluation results are shown in Table 1.

[Example 2]
The plasma etching electrode manufactured in this example has the shape shown in FIG.
First, a silicon original plate that is single crystal silicon (P-type (B-doped), crystal orientation <100>, electrical resistivity 15 Ω · cm) is processed to have a diameter of 223.5 mm and a thickness of 6.35 mm. A step structure (an outer diameter of 204.3 mm on the stepped side and a step height of 3.2 mm) was formed, and the shape of gas ejection holes (φ0.8 mm) was 3,200. Next, a male screw (valley diameter 203.2 mm, pitch 0.7 mm) was threaded on the outer peripheral surface of the step structure. This was used as the flat plate member of the electrode.
Next, Le Carbon's E + 25 graphite was processed into a ring shape with an outer diameter of 223.5 mm, an inner diameter of 203.2 mm, and a thickness of 22.25 mm, and a shape with a flange portion fixed to the device at the end, A female screw corresponding to the male screw was threaded on the inner peripheral surface of the ring wall end opposite to the side provided with the collar portion. This was used as an electrode support member.
The lithographic member obtained above and the support member were screwed together to produce a plasma etching electrode, which was subjected to actual wafer etching as an electrode member of a silicon wafer dry etching apparatus.
As a dry etching apparatus, Exel 4250 manufactured by LAM RESEARCH was used.
This was evaluated in the same manner as in Example 1.

[Comparative Example 1]
Using the silicon material and carbon material used in Example 1, a flat plate member having a diameter of 223.5 mm and a thickness of 6.35 mm, and a ring having an outer diameter of 223.5 mm, an inner diameter of 203.2 mm, and a thickness of 19 mm A plate-like support member was prepared, and a plate-like member was brazed with silver brazing to the end surface of the ring-shaped member to produce a plasma etching electrode, and the same test as in Example 2 was performed.

As can be seen from the above evaluation results, the overall resistance value and the etching rate were good.
In addition, when the etching rate was out of the standard range during use, the lithographic part, which was a consumable part, was replaced. The replacement was easily performed, and the etching rate was improved by the replacement.

  Since the plasma etching electrode of the present invention is composed of a flat plate member and a support member, it is possible to replace only the flat plate member or only the support member, and the flat plate member and the support member are joined with screws. Therefore, the replacement can be easily performed, and the occurrence of peeling due to thermal shock does not occur, so that it can be suitably used as a plasma etching electrode when an element is formed on a semiconductor wafer.

It is a figure which shows an example of the plasma etching electrode of this invention. It is a figure which shows an example of the plasma etching electrode of this invention. It is a figure which shows an example of the plasma etching electrode of this invention. It is a figure which shows an example of the plasma etching electrode of this invention. It is a figure which shows an example of the plasma etching electrode of this invention. It is a figure which shows an example of the plasma etching electrode of this invention. It is a figure which shows an example of the plasma etching electrode of this invention. It is a figure which shows an example of the plasma etching electrode of this invention. It is a conceptual diagram which shows the principle of a plasma etching apparatus. It is a figure which shows an example of the conventional plasma etching electrode. It is a figure which shows an example of the conventional plasma etching electrode. It is a figure which shows an example of the conventional plasma etching electrode.

Explanation of symbols

1 Flat member (electrode plate)
2 Support part 3 Gas ejection hole

Claims (6)

  In a plasma etching electrode comprising a flat plate member and a ring-shaped support member that supports the flat plate member, a male screw is formed on the outer peripheral surface of the flat plate member, and a female screw is formed on the inner peripheral surface of the end portion of the ring-shaped support member A plasma etching electrode formed by joining a flat plate member and a ring-shaped support member by screwing a male screw of the flat plate member and a female screw of the ring member.   2. The plasma etching electrode according to claim 1, wherein an end portion of the ring-shaped support member has a step structure, and an internal thread is formed on an inner peripheral surface of the step structure portion.   2. The plasma etching electrode according to claim 1, wherein an outer peripheral surface of the flat plate member has a step structure, and a male screw is formed on the outer peripheral surface of the step structure portion.   An end portion of the ring-shaped support member has a step structure, and an internal thread is formed on an inner peripheral surface of the step structure portion, and an outer peripheral surface of the flat plate member has a step structure. 2. The plasma etching electrode according to claim 1, wherein a male screw is formed on the outer peripheral surface of the plasma etching electrode.   In a plasma etching electrode comprising a flat plate member and a flat plate support member that supports the flat plate member, a male screw is formed on the outer peripheral surface of the flat plate member, and the flat plate support member has a recess at the center thereof. A plasma etching electrode formed by joining a flat plate member and a flat plate support member by screwing a male screw of a flat plate member and a female screw of a flat plate support member.   6. The plasma etching electrode according to claim 5, wherein the outer peripheral surface of the flat plate member has a step structure, and a male screw is formed on the outer peripheral surface of the step structure portion.

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