JP2013251367A - Plasma cvd deposition apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma CVD deposition apparatus configured to suppress deformation of electrodes due to film deposition.SOLUTION: A plasma CVD deposition apparatus includes: a chamber; an anode electrode that includes a loading surface configured to load thereon a substrate as a film formation processing object, and is disposed in the chamber; a cathode electrode that is disposed oppositely to the loading surface in the chamber and is formed of a carbon material whose surface is at least partially coated with glassy carbon; and an AC power source configured to bring process gas into a plasma state between the anode electrode and the cathode electrode by supplying an AC power between the anode electrode and the cathode electrode.

Description

  The present invention relates to a plasma CVD film forming apparatus for forming a film by forming plasma.

  In the manufacturing process of a semiconductor device, a plasma processing apparatus is used for processes such as film formation, etching, and ashing because of high-precision process control. For example, as a film forming apparatus, a plasma chemical vapor deposition (CVD) film forming apparatus is known in which a plasma is formed between a cathode electrode and an anode electrode constituting parallel plates to perform a film forming process. In the plasma CVD film forming apparatus, the raw material gas is turned into plasma by high frequency power or the like, and a thin film is formed on the substrate by a chemical reaction. For example, there has been proposed a plasma CVD film forming apparatus in which a plurality of electrode plates are prepared and a processing capacity is improved by arranging a substrate on each electrode plate (see, for example, Patent Document 1).

International Publication No. 02/20871 Pamphlet

  In the plasma CVD film forming apparatus, a metal material such as aluminum (Al), an alloy thereof, and stainless steel (SUS) is used for the cathode electrode.

  When a thin film is formed on a substrate, the film is deposited not only on the substrate but also on the anode electrode and the cathode electrode. When the thickness of the deposited film exceeds a certain amount, deformation or breakage of the anode electrode or the cathode electrode occurs due to the stress of the film. As a result, problems such as an abnormal film thickness distribution and a decrease in film formation rate occur. Even when the electrode is not deformed, if the film is deposited thick, the roughness of the surface of the cathode electrode or the anode electrode increases. As the surface roughness increases, the plasma state changes compared to immediately after the start of the film formation process, and problems such as film formation rate fluctuations and film quality fluctuations occur.

  In order to avoid these problems, it is necessary to clean the cathode electrode and the anode electrode by mechanical cleaning such as medicinal cleaning or sand blasting after the film formation process for a certain period. When the cleaning frequency is high, not only the operation rate of the film forming apparatus is lowered, but also the maintenance cost increases.

  In view of the above problems, an object of the present invention is to provide a plasma CVD film forming apparatus in which deformation of an electrode due to film deposition is suppressed.

  According to one aspect of the present invention, (a) a chamber, (b) a mounting surface on which a substrate to be deposited is mounted, an anode electrode disposed in the chamber, and (c) A cathode electrode made of a carbon material at least partially coated with glassy carbon, disposed so as to face the mounting surface; and (d) supplying AC power between the anode electrode and the cathode electrode, There is provided a plasma CVD film forming apparatus including an AC power source for bringing a process gas into a plasma state between an electrode and a cathode electrode.

  ADVANTAGE OF THE INVENTION According to this invention, the plasma CVD film-forming apparatus with which the deformation | transformation of the electrode resulting from film deposition was suppressed can be provided.

It is a schematic diagram which shows the structure of the plasma CVD film-forming apparatus which concerns on the 1st Embodiment of this invention. It is typical sectional drawing which shows the structure of the cathode electrode of the plasma CVD film-forming apparatus which concerns on the 1st Embodiment of this invention. It is typical sectional drawing which shows the structure of the anode electrode of the plasma CVD film-forming apparatus which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the example of the discharge structure formed in the cathode electrode of the plasma CVD film-forming apparatus which concerns on the 1st Embodiment of this invention, Fig.4 (a) is a top view, FIG.4 (b) is a figure. It is sectional drawing along the IV-IV direction of 4 (a). It is a schematic diagram which shows the other example of the discharge structure formed in the cathode electrode of the plasma CVD film-forming apparatus which concerns on the 1st Embodiment of this invention, Fig.5 (a) is a top view, FIG.5 (b) These are sectional drawings along the VV direction of Fig.5 (a). FIG. 6A is a schematic view showing still another example of the discharge structure formed on the cathode electrode of the plasma CVD film forming apparatus according to the first embodiment of the present invention. FIG. 6A is a perspective view, and FIG. ) Is a cross-sectional view taken along the VI-VI direction of FIG. It is typical sectional drawing which shows the structure of the cathode electrode of the plasma CVD film-forming apparatus which concerns on the 1st Embodiment of this invention. It is typical sectional drawing which shows the other structure of the cathode electrode of the plasma CVD film-forming apparatus which concerns on the 1st Embodiment of this invention. It is typical sectional drawing which shows the further another structure of the cathode electrode of the plasma CVD film-forming apparatus which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the cathode electrode of the plasma CVD film-forming apparatus which concerns on the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic. Further, the embodiment described below exemplifies an apparatus and a method for embodying the technical idea of the present invention, and the embodiment of the present invention has the following structure and arrangement of components. It is not something specific. The embodiment of the present invention can be variously modified within the scope of the claims.

(First embodiment)
As shown in FIG. 1, the plasma CVD film forming apparatus 1 according to the first embodiment of the present invention has a chamber 10 and a mounting surface 200 on which a substrate 100 to be formed is mounted. The cathode electrode 30 made of a carbon material having at least a part of the surface covered with glassy carbon, and the anode electrode 20. And an AC power supply 40 that supplies AC power between the cathode electrode 30 and the process gas 60 between the anode electrode 20 and the cathode electrode 30 in a plasma state. According to the plasma CVD film forming apparatus 1, a thin film whose main component is a raw material contained in the process gas 60 is formed on the substrate 100.

  An example of the structure of the cathode electrode 30 is shown in FIG. The cathode electrode 30 includes a main body portion 31 made of a carbon material and a glassy carbon film 32 that covers the surface of the main body portion 31. The main body 31 is made of, for example, carbon. And the surface of the main-body part 31 is coat | covered with the glassy carbon film 32 by apply | coating resin containing a carbon grain to the surface of the main-body part 31, and making it dry by high temperature baking. The film thickness of the glassy carbon film 32 is, for example, about 1 μm.

  In the plasma CVD film forming apparatus 1 shown in FIG. 1, a substrate mounting apparatus is used as the anode electrode 20. In the example shown in FIG. 1, the anode electrode 20 is grounded via the chamber 10.

  The substrate mounting apparatus used as the anode electrode 20 can adopt a structure in which, for example, a plurality of mounting surfaces 200 are overlapped in the normal direction. That is, as shown in FIG. 1, a mounting surface 200 is defined as a main surface, a plurality of substrate mounting plates 201 that are spaced apart from each other and arranged in parallel, and a fixing plate that fixes the bottom of each of the substrate mounting plates 201 202 can be employed. The substrate 100 is stored in the plasma CVD film forming apparatus 1 while being mounted on the substrate mounting apparatus, and is taken out after the film forming process. The mounting surface 200 extends in the vertical direction, and the substrate 100 is held vertically in the chamber 10. Although FIG. 1 shows an example in which there are two substrate mounting plates 201, the number of substrate mounting plates 201 is not limited to two.

  In the plasma CVD film forming apparatus 1, the anode electrode 20 on which the substrate 100 is mounted is carried into the chamber 10. Thereafter, a process gas 60 containing a source gas for film formation is introduced into the chamber 10 from a gas supply device (not shown). After introducing the process gas 60, the pressure in the chamber 10 is adjusted by an exhaust device (not shown).

  For example, the process gas 60 is introduced from below the chamber 10 and exhausted from above. By introducing the process gas 60 from below, the gas molecules and radical particles that have been converted into plasma with a low specific gravity naturally flow upward on the surface of the cathode electrode 30 as an upward flow. For this reason, the process gas is uniformly supplied to the surface of the cathode electrode 30.

  After the pressure of the process gas 60 in the chamber 10 is adjusted to a predetermined gas pressure, a predetermined AC power is supplied between the cathode electrode 30 and the anode electrode 20 by the AC power source 40. Thereby, the process gas 60 in the chamber 10 is turned into plasma. By exposing the substrate 100 to the formed plasma, a desired thin film mainly composed of the raw material contained in the raw material gas is formed on the exposed surface of the substrate 100. Note that the temperature of the substrate 100 during the film forming process may be set by the heater 50 shown in FIG. By setting the temperature of the substrate 100 during the film formation process to a predetermined temperature, the film formation speed can be increased and the film quality can be improved.

A desired thin film can be formed by appropriately selecting a source gas in the plasma CVD film forming apparatus 1. For example, a silicon semiconductor thin film, a silicon nitride thin film, a silicon oxide thin film, a silicon oxynitride thin film, a carbon thin film, or the like can be formed on the substrate 100. Specifically, a silicon nitride (SiN) film is formed on the substrate 100 using a mixed gas of ammonia (NH ₃ ) gas and silane (SiH ₄ ) gas. Alternatively, a silicon oxide (SiOx) film is formed on the substrate 100 using a mixed gas of silane (SiH ₄ ) gas and N ₂ O gas.

  During the film forming process, the cathode electrode 30 of the plasma CVD film forming apparatus 1 is always discharged, and a film is continuously deposited on the cathode electrode 30. Since the deposited film has stress, if the film is deposited so that the stress of the film exceeds the bending strength of the cathode electrode 30, the cathode electrode 30 may be deformed.

  However, the cathode electrode 30 of the plasma CVD film forming apparatus 1 has a structure in which the surface of the main body 31 is covered with a glassy carbon film 32 as shown in FIG. Glassy carbon has the same conductivity and thermal conductivity as ordinary carbon materials, but has excellent impermeability, impermeability, barrier properties, and chemical resistance, and generates particles, generates dust, and powders. It is a material that has the characteristic of less dropping. For this reason, when continuous discharge is performed using the cathode electrode 30 whose surface is coated with glassy carbon, the surface of the glassy carbon is chemically inactive, so that the surface of the cathode electrode 30 is deposited on the surface. Adhesiveness with the film is poor. For this reason, the film deposited on the surface of the cathode electrode 30 is easily peeled off. As a result, the film is not deposited thick on the surface of the cathode electrode 30, and the cathode electrode 30 is prevented from being deformed or damaged by the stress of the deposited film.

  Note that a film is continuously deposited on the anode electrode 20 during the film forming process. For this reason, stress due to the deposited film is also applied to the anode electrode 20, and the anode electrode 20 may be deformed similarly to the cathode electrode 30. For this reason, it is preferable to coat the surface of the anode electrode 20 with glassy carbon. Specifically, as shown in FIG. 3, for example, a structure in which the surface of a main body 21 made of a carbon material such as carbon is covered with a glassy carbon film 22 is employed for the anode electrode 20.

  When the distance between the anode electrode 20 and the cathode electrode 30 exceeds the specified range, problems such as an abnormal thickness distribution of the thin film formed on the substrate 100 to be deposited and a decrease in deposition rate occur. However, by covering the surfaces of the anode electrode 20 and the cathode electrode 30 with glassy carbon, deformation of the anode electrode 20 and the cathode electrode 30 is suppressed, and the distance between the anode electrode 20 and the cathode electrode 30 can be kept at a predetermined value. it can.

  Further, in order to generate a high-density plasma using hollow cathode discharge, a concave-convex structure (hereinafter referred to as “discharge structure”) formed by arranging concave portions, through-holes and the like on the surface of the cathode electrode 30. May be formed. A hollow cathode discharge can be generated using a hollow cathode electrode having a discharge structure.

  For example, a recess is formed on the surface of the cathode electrode 30 to form a discharge structure. Specifically, as shown in FIGS. 4A and 4B, a groove 301 may be arranged on the surface of the cathode electrode 30 to form a recess. Although FIG. 4A shows an example in which the grooves 301 are formed in a lattice shape, the arrangement of the grooves 301 is not limited to the lattice shape. Alternatively, as shown in FIGS. 5A and 5B, a plurality of dimples 302 may be arranged on the surface of the cathode electrode 30 to form a recess.

  Alternatively, as the discharge structure, a structure in which a through-hole 303 that penetrates the cathode electrode 30 in the thickness direction as shown in FIGS. 6A and 6B can be adopted. The opening of the through hole 303 is formed on the surface of the cathode electrode 30 so as to face the mounting surface 200 of the substrate mounting plate 201. The film thickness d of the cathode electrode 30 shown in FIGS. 6A and 6B is, for example, about 5 mm. The diameter of the through hole 303 is set to about 3.8 mm to 8.0 mm so as not to be clogged and easy to maintain, and is, for example, 5 mm.

  Plasmas excited on both surfaces of the cathode electrode 30 shown in FIGS. 6A and 6B are connected by a through hole 303. Therefore, the difference in density of the plasma concentration on both sides of the cathode electrode 30 is naturally corrected, and a plasma space having a uniform density can be generated on both sides of the cathode electrode 30. Therefore, by adopting a multi-hollow cathode structure in which a large number of through holes 303 are formed in the cathode electrode 30, uniform multi-hollow discharge can be obtained on both surfaces of the cathode electrode 30. The “multi-hollow discharge” is a discharge generated on the surface of the cathode electrode 30 by combining the hollow cathode discharges generated in the respective through holes 303. Thereby, uniform high-density plasma can be realized on the surface of the cathode electrode 30. As a result, the source gas is efficiently decomposed, and a thin film is uniformly formed on the substrate 100 in a large area at a high speed.

  By the way, when the cathode electrode 30 is a hollow cathode electrode having a discharge structure, a film is also deposited on the surface of the recess formed in the cathode electrode 30 and the inner wall of the through hole 303 during the film forming process. The film deposited on the surface of the recess and the inner wall of the through-hole 303 by hollow cathode discharge has a very high hardness and further has a stress that tends to spread outward. For this reason, the cathode electrode 30 is more likely to be deformed.

  On the other hand, the deformation | transformation of the cathode electrode 30 can be suppressed by coat | covering the surface of a recessed part and the inner wall of the through-hole 303 with glassy carbon. FIG. 2 shows an example in which the entire surface of the cathode electrode 30 is covered with glassy carbon. For example, as shown in FIGS. 7 and 8, only the surface of the recess is covered with the glassy carbon film 32. 9, only the surface of the inner wall of the through hole 303 may be covered with the glassy carbon film 32.

  Hereinafter, the cathode electrode 30 whose surface is coated with glassy carbon and the cathode electrode of a comparative example whose surface is not coated with glassy carbon (hereinafter referred to as “cathode electrode 30A”) are formed by plasma CVD. The result of investigating the degree of deformation caused by the process is shown. For the investigation, a plasma CVD film forming apparatus having the configuration shown in FIG. 1 was used.

  The cathode electrode used for the investigation is a carbon plate having an area of 200 mm × 200 mm and a thickness d of 5 mm. A hollow cathode electrode in which through holes 303 having a diameter of 5 mm are arranged at a pitch of 6.5 mm was used. The cathode electrode 30 according to the first embodiment has a structure in which a glassy carbon film 32 is coated on the surface of a main body 31 made of a carbon material (G535), and the cathode electrode 30A of the comparative example is coated with a glassy carbon film 32. It is made of carbon material (G535) that has not been made. The anode electrode 20 was a carbon plate having an area of 200 mm × 200 mm.

The temperature of the anode electrode 20 is heated to 450 ° C. by the heater 50, and a mixed gas of silane (SiH ₄ ) and ammonia (NH ₃ ) is used as a process gas 60 in the chamber 10 to form a silicon nitride (SiNx) film. Introduced. The gas flow rates are 215 sccm for silane gas and 950 sccm for ammonia gas. The pressure in the chamber 10 was adjusted to 67 Pa, and a high frequency of 250 kHz was applied at 700 W by the AC power source 40 to generate plasma in the chamber 10.

  Due to the continuous discharge for 15 days, in the cathode electrode 30A of the comparative example, the diameter of the through hole 303 which was 5 mm before the film forming process was reduced to about 3.5 mm. Further, the thickness d of the cathode electrode 30A, which was 5 mm, increased from 6.5 mm to 6.8 mm. The film formation rate was 105 nm / min immediately after the start of the treatment with almost no deposited film, but it was 67 nm / min after 15 days of continuous discharge, a decrease of 36%.

  On the other hand, in the cathode electrode 30 according to the first embodiment, the diameter of the through hole 303 was reduced only to about 4.5 mm even after 15 days of continuous discharge. Further, the thickness d is about 5.3 mm, and the increase in the thickness d due to the deposited film is small compared to the cathode electrode 30A of the comparative example. The film forming rate was 103 nm / min after 15 days of continuous discharge, and hardly changed from 105 nm / min immediately after the start of treatment. Thus, the cathode electrode 30 whose surface was coated with the glassy carbon film 32 was in almost the same state as immediately after the start of treatment even after 15 days of continuous discharge.

  As described above, according to the plasma CVD film forming apparatus 1 according to the first embodiment of the present invention, the surface of the cathode electrode 30 made of a carbon material is coated with glassy carbon, whereby the cathode electrode 30 is coated. Deformation of the cathode electrode 30 due to the deposited film is suppressed. For this reason, the frequency which cleans the cathode electrode 30 becomes low, and the fall of the operation rate of the plasma CVD film-forming apparatus 1 and the increase in maintenance cost can be suppressed.

(Second Embodiment)
In the plasma CVD film forming apparatus 1 according to the second embodiment of the present invention, the cathode electrode 30 is made of a carbon material or a carbon fiber reinforced carbon composite material. Other configurations are the same as those of the first embodiment shown in FIG.

  A carbon fiber reinforced carbon composite material (C / C composite) is a carbon-based material reinforced with carbon fibers and has a property that it is difficult to extend as compared with a metal material. Therefore, by using a carbon fiber reinforced carbon composite material having a high Young's modulus for the cathode electrode 30, deformation of the cathode electrode 30 due to the stress of the film deposited on the cathode electrode 30 is suppressed.

  In particular, when the cathode electrode 30 is a hollow cathode electrode having a through-hole 303, it is effective to employ a carbon material or a carbon fiber reinforced carbon composite material for the cathode electrode 30. As already described, the film deposited on the inner wall of the through-hole 303 by hollow cathode discharge has a very high hardness and has a stress of spreading outward. For this reason, the cathode electrode 30 is more likely to be deformed. However, in the cathode electrode 30 made of a carbon material or a carbon fiber reinforced carbon composite material, deformation of the cathode electrode 30 due to stress caused by a film deposited on the inner wall of the through hole 303 is suppressed.

  Furthermore, as shown in FIG. 10, it is preferable not to arrange the through hole 303 in the outer peripheral region within a certain distance t from the outer edge of the surface of the cathode electrode 30 where the stress is most concentrated. Further, for example, the surface of the cathode electrode 30 is also applied to the discharge structure which is the recess shown in FIGS. 4A, 4B, 5A, and 5B, similarly to the through hole 303. It is preferable not to form in the outer peripheral area within a certain distance t from the outer edge.

As a result of experiments and verifications by the inventors, it is possible to suppress the deformation of the cathode electrode 30 due to the discharge structure disposed at the outer edge portion of the cathode electrode 30 by setting the distance t from the outer edge to 5 mm or more. confirmed. For this reason, for example, the opening of the through hole 303 is not disposed within 8 mm from the outer edge of the surface of the cathode electrode 30.

  As described above, by not disposing the discharge structure at the end of the cathode electrode 30, it is possible to prevent concentration of film stress that causes deformation or breakage of the cathode electrode 30.

  When the cathode electrode 30 made of a carbon material or a carbon fiber reinforced carbon composite material is used, the film formation rate is low when no film is deposited on the cathode electrode 30, and the film is deposited on the cathode electrode 30. This stabilizes the film formation rate. For this reason, it is preferable to set a time for depositing the film on the cathode electrode 30 before forming a thin film on the substrate 100 to be deposited. The inventors have confirmed that a stable discharge state can be realized by forming a thin film on the substrate 100 after depositing a film on the cathode electrode 30 for 10 minutes. Thereby, a stable film formation rate can be obtained.

  In the following, with respect to the cathode electrode 30 made of a carbon material (G535) and the cathode electrode of a comparative example made of an aluminum material (A1050) (hereinafter referred to as “cathode electrode 30B”), the deformation caused by the film forming process by the plasma CVD method. The result of investigating the degree of is shown. For the investigation, a plasma CVD film forming apparatus having the configuration shown in FIG. 1 was used.

  As the cathode electrode used for the investigation, a hollow cathode electrode having an area of 200 mm × 200 mm, a thickness d of 5 mm, and through-holes 303 having a diameter of 5 mm arranged at a pitch of 6.5 mm was used. The anode electrode 20 was a carbon plate having an area of 200 mm × 200 mm.

The temperature of the anode electrode 20 is heated to 450 ° C. by the heater 50, and a mixed gas of silane (SiH ₄ ) and ammonia (NH ₃ ) is used as a process gas 60 in the chamber 10 to form a silicon nitride (SiNx) film. Introduced. The gas flow rates are 215 sccm for silane gas and 950 sccm for ammonia gas. The pressure in the chamber 10 was adjusted to 67 Pa, and a high frequency of 250 kHz was applied at 700 W by the AC power source 40 to generate plasma in the chamber 10. After the film formation process by continuous discharge, the film deposited on the cathode electrode was removed with hydrofluoric acid, and the deformation amount of the cathode electrode was measured.

  The cathode electrode 30A of the comparative example was expanded by the stress of the film deposited in the through hole 303 when the film formation process by continuous discharge was performed for 20 hours, and the area of the cathode electrode 30B increased to 210 mm × 210 mm. Also, warpage of about 1 mm occurred in the planar direction.

  On the other hand, in the cathode electrode 30 according to the second embodiment, even after the film formation process by continuous discharge is performed for 100 hours, the area of the cathode electrode 30 remains 200 mm × 200 mm and does not change, and the warpage in the planar direction also occurs. Did not occur.

  As explained above, according to the plasma CVD film-forming apparatus 1 which concerns on the 2nd Embodiment of this invention, by using the cathode electrode 30 which consists of a carbon material or a carbon fiber reinforced carbon composite material, from Al etc. The deformation of the cathode electrode 30 due to the film deposited on the cathode electrode 30 is suppressed as compared with the metal cathode electrode. For this reason, the frequency which cleans the cathode electrode 30 becomes low, and the fall of the operation rate of the plasma CVD film-forming apparatus 1 and the increase in maintenance cost can be suppressed. The anode electrode 20 may be made of a carbon material or a carbon fiber reinforced carbon composite material.

  As mentioned above, although this invention was described by embodiment, it should not be understood that the description and drawing which form a part of this indication limit this invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. That is, it goes without saying that the present invention includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 ... Plasma CVD film-forming apparatus 10 ... Chamber 20 ... Anode electrode 21 ... Main part 22 ... Glassy carbon film 30 ... Cathode electrode 31 ... Main part 32 ... Glassy carbon film 40 ... AC power supply 50 ... Heater 60 ... Process gas 100 ... Substrate 200 ... Mounting surface 201 ... Substrate mounting plate 202 ... Fixing plate 301 ... Groove 302 ... Dimple 303 ... Through hole

Claims (7)

A chamber;
An anode electrode having a mounting surface on which a substrate to be deposited is mounted, and disposed in the chamber;
A cathode electrode made of a carbon material at least partially covered with glassy carbon, disposed so as to face the mounting surface in the chamber;
A plasma CVD film forming apparatus, comprising: an AC power supply that supplies AC power between the anode electrode and the cathode electrode to bring a process gas into a plasma state between the anode electrode and the cathode electrode.   The plasma CVD film forming apparatus according to claim 1, wherein the anode electrode has a structure in which a surface of a carbon material is covered with the glassy carbon.   The cathode electrode has a recess formed in a main surface facing the mounting surface or a through hole having an opening in each of two main surfaces facing the substrate, and a hollow cathode between the anode electrode and the anode electrode The plasma CVD film forming apparatus according to claim 1, wherein the plasma CVD film forming apparatus is a hollow cathode electrode that causes discharge.   Of the cathode electrode, when the concave portion is formed on the main surface, only the surface of the concave portion is covered with the glassy carbon, and when it has the through hole, the surface of the inner wall of the through hole The plasma CVD film forming apparatus according to claim 3, wherein only the glassy carbon is coated. A chamber;
An anode electrode having a mounting surface on which a substrate to be deposited is mounted, and disposed in the chamber;
A cathode electrode made of a carbon material or a carbon fiber reinforced carbon composite material, disposed so as to face the mounting surface in the chamber;
A plasma CVD film forming apparatus, comprising: an AC power supply that supplies AC power between the anode electrode and the cathode electrode to bring a process gas into a plasma state between the anode electrode and the cathode electrode.   The cathode electrode has a recess formed in a main surface facing the mounting surface or a through hole having an opening in each of two main surfaces facing the substrate, and a hollow cathode between the anode electrode and the anode electrode 6. The plasma CVD film forming apparatus according to claim 5, wherein the plasma CVD film forming apparatus is a hollow cathode electrode that causes discharge.   The plasma CVD film forming apparatus according to claim 6, wherein the recess or the opening of the through hole is not disposed in an outer peripheral region within 5 mm from the outer edge of the surface of the cathode electrode.

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