TWI390077B - Plasma chemical vapor deposition apparatus and manufacturing method of magnetic recording medium - Google Patents

Description

Plasma chemical vapor deposition device and method for manufacturing magnetic recording medium

The present invention relates to a plasma chemical vapor deposition (CVD) apparatus and a method of manufacturing a magnetic recording medium, and more particularly to a method of forming a fine film on a film-formed substrate by lengthening a distance between a cathode electrode and a film-formed substrate. And a plasma CVD apparatus of a high hardness film.

Fig. 2 is a cross-sectional view showing a conventional plasma CVD apparatus in a mode. The plasma CVD apparatus has a structure in which a film formation substrate (for example, a disk substrate) 101 is bilaterally symmetrical, and can be simultaneously formed on both surfaces of the film formation substrate 101. In the second drawing, the film is opposed to The film formation substrate 101 shows the left side, and the right side is omitted.

The plasma CVD apparatus has a chamber 102 in which a hot cathode (cathode electrode) 103 is formed. Both ends of the hot cathode 103 are electrically connected to an alternating current power source 105 located outside the chamber 102. One end of the AC power source 105 is electrically connected to the ground 106.

A horn anode 104 having a funnel shape is disposed in the chamber 102, and the horn anode 104 is electrically connected to the DC power source 107. The positive potential side of the DC power source 107 is electrically connected to the angled anode 104, and the negative potential side of the DC power source 107 is electrically connected to the ground 106.

The film formation substrate 101 is disposed in the chamber 102. The distance 12 between the hot cathode 103 and the film formation substrate 101 is 163.5 mm.

The film formation substrate 101 is electrically connected to a DC power source (DC power source) 112 as a power source for ion acceleration. The negative potential side of the DC power source 112 is electrically connected to the film formation substrate 101, and the positive potential side of the DC power source 112 is electrically connected to the ground 106.

In the chamber 102, a plasma wall 108 is disposed so as to cover a space between each of the hot cathode 103 and the angular anode 104 and the film formation substrate 101. The plasma wall 108 is electrically connected to a drift potential (not shown). Further, the plasma wall 108 has a cylindrical shape, and the inner diameter B of the cylinder is 100 mm or more and 200 mm or less.

Next, a method of forming a DLC (Diamond Like Carbon) film on the film formation substrate 1 by using the plasma CVD apparatus shown in the second circle will be described.

First, the inside of the chamber 102 is formed into a predetermined vacuum state, and for example, toluene (C ₇ H ₈ ) gas is introduced into the chamber 102 as a film forming material gas. After a predetermined pressure is formed in the chamber 102, an alternating current is supplied to the hot cathode 103 by the alternating current power source 105, whereby the hot cathode 103 is heated. Further, a DC current is supplied to the angular anode 104 by the DC power source 107, and a DC current is supplied to the film formation substrate 101 by the DC power source 112.

By the heating of the hot cathode 103, a large amount of electrons are released from the hot cathode 103 toward the angular anode 104, and glow discharge is started between the hot cathode 103 and the angular anode 104. The toluene gas which is the film forming material gas inside the chamber 102 is ionized by a large amount of electrons, and is formed into a plasma state. At this time, a reaction represented by the following formula (1) occurs. Then, the film formation material molecules in the plasma state are directly accelerated by the negative potential of the film formation substrate 101, and fly away in the direction of the film formation substrate 101 to adhere to the surface of the film formation substrate 101. Thereby, a thin DLC film is formed on the film formation substrate 101. At this time, a reaction of the following formula (2) occurs on the surface of the film formation substrate 101.

C ₇ H ₈ +e ^- →C ₇ H ₈ ⁺ +2e ^- ‧‧‧(1)

C ₇ H ₈ ⁺ +e ^- →C ₇ H ₂ +3H ₂ ↑‧‧‧(2)

In the conventional plasma CVD apparatus, the distance 12 between the hot cathode 103 and the film formation substrate 101 is shortened as much as possible to 163.5 mm, whereby the DLC film formed on the surface of the film formation substrate 101 can be formed. The film formation amount per unit time (see, for example, Patent Documents 1 and 2).

(Patent Document 1) Japanese Patent No. 3299721 (paragraphs 0015 to 0023, FIG. 1)

(Patent Document 2) Japanese Patent 3930183 (Fig. 1)

As described above, in the conventional plasma CVD apparatus, in order to increase the amount of film formation per unit time per unit time, the distance 12 between the cathode electrode 103 and the film formation substrate 101 is shortened as much as possible.

However, if the distance 12 is shortened, it is difficult to sufficiently increase the hardness of the film formed on the film formation substrate, and it is not possible to form a film of the high hardness film on the film formation substrate. The reason is based on the fact that the acceleration distance of the ionized film-forming material gas is shortened because the distance 12 is shortened, and it is impossible to form a fine film on the film formation substrate.

The present invention has been made in consideration of the circumstances as described above, and an object thereof is to provide a film which can form a film of a fine and high hardness on a film-formed substrate by lengthening the distance between the cathode electrode and the film-formed substrate. Plasma CVD apparatus.

In order to solve the above problems, the plasma CVD apparatus of the present invention is characterized by having:

Chamber;

a funnel-shaped anode disposed in the chamber;

a filament-shaped cathode disposed in the chamber and surrounded by a central portion of the inner circumferential surface of the anode;

Arranging in the chamber to hold a holding portion of the film formation substrate disposed to face the cathode and the anode;

Arranging in the chamber to cover a space between the film formation substrate held by the holding portion and the cathode and the anode, and being formed as a plasma wall having a drift potential;

An alternating current power source electrically connected to the cathode;

a first direct current power source electrically connected to the anode;

a second DC power source electrically connected to the film formation substrate held by the holding portion;

a gas supply mechanism for supplying a material gas into the chamber; and

An exhaust mechanism for exhausting the chamber, wherein the anode has a maximum inner diameter side facing the film formation substrate, and the plasma wall has a cylindrical shape or a polygonal shape, and an inner diameter of the cylinder or a plurality of corners is 100 mm or more and 200 mm or less, the distance between the cathode and the film formation substrate held by the holding portion is 200 mm or more and 300 mm or less, and the raw material gas plasma is discharged by discharging between the cathode and the anode. Chemical.

According to the plasma CVD apparatus, when the inner diameter of the cylindrical or polygonal plasma wall is set to 100 mm or more and 200 mm or less, the filament cathode and the film formation substrate are as much as possible as compared with the prior art. The distance between the lengths is longer than 200 mm and 300 mm or less. That is, in the prior art, the distance between the cathode and the film formation substrate is shortened as much as possible, whereas in the present embodiment, the distance between the cathode and the film formation substrate is lengthened as much as possible. Thereby, the acceleration distance of the ionized material gas can be lengthened, so that the ionized material gas can be collided with the film formation substrate faster than the conventional plasma CVD apparatus. As a result, the film formation can be made finer on the film to be formed on the film formation substrate, and the hardness can be increased.

Further, in the plasma CVD apparatus of the present invention, it is preferable to additionally provide a magnet for generating a magnetic force in a region where the material gas is plasmaized, wherein the magnet has a cylindrical shape or a polygonal shape and belongs to a cylinder or a polygonal shape thereof. The magnetic force at the center of the magnet at the center of the inner diameter is 50 Gauss or more and 200 Gauss or less. Thereby, the plasma density can be increased, and as a result, the film formed on the film formation substrate can be made finer and the hardness can be increased.

Further, in the plasma CVD apparatus of the present invention, it is preferable that the magnet is disposed outside the cathode and the anode to surround the cathode and the anode.

Further, in the plasma CVD apparatus of the present invention, the distance between the center of the magnet and the cathode is preferably within 50 mm, and more preferably within 35 mm.

Further, in the plasma CVD apparatus of the present invention, the magnet is preferably a neodymium magnet.

The method for producing a magnetic recording medium of the present invention is a method for producing any of the above plasma CVD devices, characterized in that:

The film formation substrate on which at least the magnetic layer is formed on the nonmagnetic substrate is held by the holding portion,

The raw material gas is formed into a plasma state by discharge between the filament cathode and the anode heated under vacuum in the chamber, so that the plasma is accelerated and held in the holding portion. The surface of the substrate is formed to form a protective layer mainly composed of carbon.

Further, in the method of producing a magnetic recording medium of the present invention, it is preferable that the raw material gas system is a source gas for forming a DLC layer as the protective layer on the film formation substrate, and includes a gas containing carbon and hydrogen.

As described above, according to the present invention, it is possible to provide a plasma CVD apparatus which can form a film having a high density and a high hardness on a film formation substrate by lengthening the distance between the cathode electrode and the film formation substrate.

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a cross-sectional view showing a plasma CVD apparatus according to an embodiment of the present invention in a mode. This plasma CVD apparatus has a structure in which a film formation substrate (for example, a disk substrate) 1 is bilaterally symmetrical, and can be simultaneously formed on both surfaces of the film formation substrate 1. However, in the first circle, it is relative to The film formation substrate 1 is shown on the left side, and the right side is omitted.

The plasma CVD apparatus has a chamber 2 in which a filament-shaped cathode electrode (hot cathode) 3 made of, for example, ruthenium is formed. Both ends of the hot cathode 3 are electrically connected to an AC power source 5 located outside the chamber 2, and the AC power source 5 is disposed in a state in which the chamber 2 is insulated. In the case of the AC power source 5, a power source of, for example, 0 to 50 V and 10 to 50 A (amperes) can be used. One end of the AC power source 5 is electrically connected to the ground 6.

An anode electrode (angular anode) 4 having a funnel shape is disposed in the chamber 2 so as to surround the periphery of the hot cathode 3, and the angular anode 4 has a shape such as a speaker. The horn anode 4 is electrically connected to a DC power source (DC power source) 7, and the DC power source 7 is disposed in a state in which the chamber 2 is insulated. The positive potential side of the DC power source 7 is electrically connected to the angular anode 4, and the negative potential side of the DC power source 7 is electrically connected to the ground 6. In the case of the DC power source 7, a power source such as 0 to 500 V and 0 to 7.5 A (amperes) can be used.

The film formation substrate 1 is disposed in the chamber 2, and the film formation substrate 1 is disposed to face the hot cathode 3 and the angular anode 4. In detail, the hot cathode 3 is surrounded by the vicinity of the central portion of the inner peripheral surface of the angular anode 4, and the angular anode 4 is disposed such that its maximum inner diameter side faces the film formation substrate 1.

The distance 1 between the hot cathode 3 and the film formation substrate 1 is preferably as long as possible, and specifically, it is preferably 200 mm or more and 300 mm or less. If the distance 1 is less than 200 mm, the hardness of the film formed on the film formation substrate 1 becomes low, and if the distance 1 exceeds 300 mm, the film formation rate becomes slow, which is less practical.

The film formation substrate 1 is sequentially supplied to the illustrated position by a holder (holding unit) (not shown) and a transfer device (processing robot or rotary index table) (not shown).

The film formation substrate 1 is electrically connected to a DC power source (DC power source) 12 as a power source for ion acceleration, and the DC power source 12 is disposed in a state in which the chamber 2 is insulated. The negative potential side of the DC power source 12 is electrically connected to the film formation substrate 1, and the positive potential side of the DC power source 12 is electrically connected to the ground 6. In the case of the DC power source 12, a power source such as 0 to 1500 V, 0 to 100 mA (milliampere) can be used.

In the chamber 2, a plasma wall 8 is disposed so as to cover a space between each of the hot cathode 3 and the angular anode 4 and the film formation substrate 1. The plasma wall 8 is electrically connected to a drift potential (not shown), and is disposed in a state in which the chamber 2 is insulated. Further, the plasma wall 8 has a cylindrical shape or a polygonal shape, and the inner diameter B of the cylinder or the polygonal shape is 100 mm or more and 200 mm or less. When the inner diameter B is set to less than 100 mm, ionization of the material gas becomes too high in the vicinity of the angular anode 4, and free carbon (i.e., coal) is likely to occur, which is less desirable. In addition, when the inner diameter B is more than 200 mm, ionization of the material gas is too low in the vicinity of the angular anode 4, and it is difficult to form a fine film on the film formation substrate 1, and even if a crucible described later is used, Magnets are also difficult to form high magnetic fields.

A film thickness correction plate 8a is provided on an end portion of the plasma wall 8 on the side of the film formation substrate 1, and the film thickness correction plate 8a is electrically connected to the drift potential. The thickness of the film formed on the outer peripheral portion of the film formation substrate 1 can be controlled by the film thickness correction plate 8a.

A neodymium magnet 9 is disposed outside the chamber 2. The neodymium magnet 9 has, for example, a cylindrical shape or a polygonal shape, and the inner diameter 11 of the center of the cylinder or the center of the multi-angle side is preferably within 50 mm (more preferably within 35 mm) of the hot cathode 3 ). The center of the inner diameter 11 is the magnet center 10, and the magnet center 10 is located substantially opposite to the center of the hot cathode 3 and substantially the center of the film formation substrate 1. The neodymium magnet 9 has a magnetic force of the magnet center 10 of 50 G or more and 200 G (Gauss) or less, more preferably 50 G or more and 150 G or less. The reason why the magnetic force of the magnet center 10 is 200 G or less is based on the fact that the magnetic force of the magnet center 10 is increased to 200 G by the neodymium magnet, which is a manufacturing limit. Further, the reason why the magnetic force of the magnet center 10 is 150 G or less is more preferable because when the magnetic force of the magnet center 10 is more than 150 G, the cost of manufacturing the magnet increases.

Further, the plasma CVD apparatus has a vacuum exhaust mechanism (not shown) that evacuates the inside of the chamber 2. Further, the plasma CVD apparatus has a gas supply mechanism (not shown) that supplies a film forming material gas into the chamber 2.

Next, a method of forming a DLC film on the film formation substrate 1 using the plasma CVD apparatus shown in Fig. 1 will be described.

First, the vacuum evacuation mechanism is started, and the inside of the chamber 2 is formed into a predetermined vacuum state. Inside the chamber 2, for example, toluene (C ₇ H ₈ ) gas is introduced as a film forming material gas by the gas introduction mechanism. After the predetermined pressure is applied in the chamber 2, an alternating current is supplied to the hot cathode 3 by the alternating current power source 5, whereby the hot cathode 3 is heated. Further, a DC current is supplied to the angular anode 4 by the DC power source 7, and a DC current is supplied to the film formation substrate 1 by the DC power source 12.

By the heating of the hot cathode 3, a large amount of electrons are released from the hot cathode 3 toward the angular anode 4, and glow discharge is started between the hot cathode 3 and the angular anode 4. The toluene gas as a film forming material gas inside the chamber 2 is ionized by a large amount of electrons to be in a plasma state. At this time, since a magnetic field is generated in the region for plasma-forming the toluene gas in the vicinity of the hot cathode 3 by the neodymium magnet 9, the plasma can be made denser by the magnetic field, and the ionization efficiency can be improved. . Then, the film formation material molecules in the plasma state are directly accelerated by the negative potential of the film formation substrate 1, and fly away in the direction of the film formation substrate 1, and adhere to the surface of the film formation substrate 1. Thereby, a thin DLC film is formed on the film formation substrate 1 . At this time, a reaction of the following formula (3) occurs on the surface of the film formation substrate 1.

C ₇ H ₈ +e ^- →C _a H _b +xH ₂ ↑‧‧‧(3)

Next, a method of manufacturing a magnetic recording medium using the plasma CVD apparatus shown in Fig. 1 will be described.

First, a film formation substrate having at least a magnetic layer formed on a non-magnetic substrate is prepared, and the film formation substrate is held in a holding portion. Next, the raw material gas is formed into a plasma state by discharge between the hot cathode 3 heated in the chamber 2 under a predetermined vacuum condition and the angular anode 4, so that the plasma is accelerated and held in the holding portion. The surface of the film-formed substrate. Thereby, a protective layer containing carbon as a main component is formed on the surface of the film formation substrate.

According to the above embodiment, when the inner diameter B of the cylindrical or polygonal plasma wall 8 is set to 100 mm or more and 200 mm or less, the distance 1 between the hot cathode 3 and the film formation substrate 1 can be lengthened as much as possible. That is, in the prior art, the distance between the hot cathode and the film-formed substrate is minimized. In the present embodiment, the distance between the hot cathode and the film-formed substrate is increased as much as possible. Specifically, It is formed into 200 mm or more and 300 mm or less. Thereby, since the acceleration distance of the ionized film forming material gas can be lengthened, the speed at which the ionized film forming material gas collides with the film formation substrate 1 can be made faster than the conventional plasma CVD apparatus. As a result, b of the above formula (3) can be reduced as compared with the DLC film formed by a conventional plasma CVD apparatus. Thereby, the film formation can be made finer in the DLC film of the film formation substrate, and the hardness can be increased.

Further, in the above embodiment, by disposing the neodymium magnet 9 outside the chamber 2, the plasma density occurring between the hot cathode 3 and the angular anode 4 in the present apparatus can be improved. As a result, the DLC film formed on the film formation substrate can be made finer and higher in hardness.

However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit and scope of the invention. For example, in the above embodiment, the neodymium magnet 9 is disposed outside the chamber 2, but a neodymium magnet may be disposed inside the chamber 2, and a magnet made of another material may be disposed instead of the neodymium magnet 9, Further, the neodymium magnet 9 is not necessarily required, and may be implemented without the neodymium magnet 9 being disposed.

[Example 1]

Next, the film formation conditions and results (film thickness of the DLC film, conditions for ashing the DLC film, and ashing ratio) of the DLC film formed by using the plasma CVD apparatus shown in Fig. 1 will be described.

(film formation conditions)

The inner diameter of the plasma wall B: 132mm

The distance between the hot cathode 3 and the film-formed substrate 1 is 1:238.5 mm

Distance A between hot cathode 3 and magnet center 10: 35 mm

Film-forming substrate: Si wafer

Gas: C ₇ H ₈

Gas flow rate: 3.25sccm

Pressure: 0.3Pa

Hot cathode 3: 钽 filament

AC power supply 5 output: 200W

DC power supply 7 current: 1650mA

DC power supply 12 voltage: 250V

External magnetic field: none

(result)

Film thickness of DLC film: 30nm

Knoop hardness (Hk) of DLC film: 2680

(ashing conditions and results)

Gas: O ₂

Gas flow: 50sccm

Pressure: 30Pa

Electrode: parallel plate type

Frequency applied to the high frequency of the electrode: 13.56 MHz

High frequency output applied to the electrode: 500W

Ashing rate: 85nm/min

[Comparative example]

Next, the film formation conditions and results (film thickness of the DLC film, conditions for ashing the DLC film, and ashing ratio) of the DLC film formed by using the plasma CVD apparatus shown in Fig. 2 will be described.

(film formation conditions)

Inner diameter B of the plasma wall 108: 132 mm

The distance between the hot cathode 103 and the film formation substrate 101 is 12: 163.5 mm

Film-forming substrate: Si wafer

Gas: C ₇ H ₈

Gas flow rate: 3.25sccm

Pressure: 0.3Pa

Hot cathode 103: 钽 filament

Output of AC power supply 105: 200W

DC power supply 107 current: 1650mA

DC power supply 112 voltage: 250V

External magnetic field: none

(result)

Film thickness of DLC film: 30nm

Rope hardness (Hk) of DLC film: 1800

(ashing conditions and results)

Gas: O ₂

Gas flow: 50sccm

Pressure: 30Pa

Electrode: parallel plate type

Frequency applied to the high frequency of the electrode: 13.56 MHz

High frequency output applied to the electrode: 500W

Ashing rate: 140nm/min

According to the first embodiment and the comparative example described above, by making the distance between the hot cathode and the film formation substrate longer than the comparative example, the acceleration distance of the ionized film formation material gas can be lengthened. Therefore, the speed at which the ionized film forming material gas collides with the film formation substrate can be made faster than the conventional plasma CVD apparatus. As a result, the ashing rate of the formed DLC film can be greatly reduced. Therefore, it was confirmed that the fine-densified DLC film was formed into a film, and the DLC film was subjected to high hardness.

[Embodiment 2]

Next, the film formation conditions and results (film thickness of the DLC film, conditions for ashing the DLC film, and ashing ratio) of the DLC film formed by using the plasma CVD apparatus shown in Fig. 1 will be described.

(film formation conditions)

The inner diameter of the plasma wall B: 132mm

The distance between the hot cathode 3 and the film-formed substrate 1 is 1:238.5 mm

Distance A between hot cathode 3 and magnet center 10: 35 mm

Film-forming substrate: Si wafer

Gas: C ₇ H ₈

Gas flow rate: 3.25sccm

Pressure: 0.3Pa

Hot cathode 3: 钽 filament

AC power supply 5 output: 200W

DC power supply 7 current: 1650mA

DC power supply 12 voltage: 250V

External magnetic field: 50G

(result)

Film thickness of DLC film: 30nm

Rope hardness (Hk) of DLC film: 2740

(ashing conditions and results)

Gas: O ₂

Gas flow: 50sccm

Pressure: 30Pa

Electrode: parallel plate type

Frequency applied to the high frequency of the electrode: 13.56 MHz

High frequency output applied to the electrode: 500W

Ashing rate: 76nm/min

According to the above-described Embodiment 2 and Example 1, by applying an external magnetic field of 50 G in the film formation, the ashing rate of the formed DLC film can be reduced by 9 nm/min as compared with the case where no external magnetic field is applied. The DLC film of Example 1 was very fine, so that it was reduced by 9 nm/min as compared with it, and it was very large in effect. Therefore, it was confirmed that a more finely formed DLC film was formed, and the DLC film system was further increased in hardness.

[Example 3]

Next, the film formation conditions and results (film thickness of the DLC film, conditions for ashing the DLC film, and ashing ratio) of the DLC film formed by using the plasma CVD apparatus shown in Fig. 1 will be described.

(film formation conditions)

The inner diameter of the plasma wall B: 132mm

The distance between the hot cathode 3 and the film-formed substrate 1 is 1:238.5 mm

Distance A between hot cathode 3 and magnet center 10: 35 mm

Film-forming substrate: Si wafer

Gas: C ₇ H ₈

Gas flow rate: 3.25sccm

Pressure: 0.3Pa

Hot cathode 3: 钽 filament

AC power supply 5 output: 200W

DC power supply 7 current: 1650mA

DC power supply 12 voltage: 250V

External magnetic field: 100G

(result)

Film thickness of DLC film: 30nm

Rope hardness (Hk) of DLC film: 2770

(ashing conditions and results)

Gas: O ₂

Gas flow: 50sccm

Pressure: 30Pa

Electrode: parallel plate type

Frequency applied to the high frequency of the electrode: 13.56 MHz

High frequency output applied to the electrode: 500W

Ashing rate: 74nm/min

According to the above-described Embodiment 3 and Example 2, by applying an external magnetic field of 100 G in the film formation, the ashing rate of the formed DLC film can be lowered by 2 nm/min as compared with the case of applying an external magnetic field of 50 G. The DLC film of Example 2 was very fine, so that it was reduced by 2 nm/min as compared with it, and in terms of effect, it was very large. Therefore, it was confirmed that a more finely formed DLC film was formed, and the DLC film system was further increased in hardness.

1, 101. . . Film-formed substrate

2, 102. . . Chamber

3, 103. . . Cathode electrode (hot cathode)

4, 104. . . Anode electrode (angular anode)

5,105. . . AC power

6, 106. . . Grounding power supply

7, 107. . . DC power supply

8,108. . . Plasma wall

8a. . . Film thickness correction plate

9. . . Neodymium magnet

10. . . Magnet center

11. . . Inner diameter of cylindrical neodymium magnet

12, 112. . . DC power supply

A. . . distance

B. . . the inside diameter of

1,12. . . distance

Fig. 1 is a cross-sectional view showing a plasma CVD apparatus according to an embodiment of the present invention in a mode.

Fig. 2 is a cross-sectional view showing a conventional plasma CVD apparatus in a mode.

1, 101. . . Film-formed substrate

2, 102. . . Chamber

3, 103. . . Cathode electrode (hot cathode)

4, 104. . . Anode electrode (angular anode)

5,105. . . AC power

6, 106. . . Grounding power supply

7, 107. . . DC power supply

8,108. . . Plasma wall

8a. . . Film thickness correction plate

9. . . Neodymium magnet

10. . . Magnet center

11. . . Inner diameter of cylindrical neodymium magnet

12, 112. . . DC power supply

A. . . distance

B. . . the inside diameter of

1,12. . . distance

Claims (7)

A plasma chemical vapor deposition apparatus comprising: a chamber; a funnel-shaped anode disposed in the chamber; and a filament-like shape disposed in the chamber and surrounded by a central portion of the anode inner peripheral surface a cathode; a holding portion of the film formation substrate disposed to be disposed to face the cathode and the anode; and disposed in the chamber to cover the aforementioned portion held by the holding portion a plasma wall of the film formation substrate and the cathode and the anode, and is formed as a plasma wall having a drift potential; an AC power source electrically connected to the cathode; and a first electrode electrically connected to the anode a DC power source; a second DC power source electrically connected to the film formation substrate held in the holding portion; a gas supply mechanism for supplying a material gas into the chamber; and an exhaust mechanism for exhausting the chamber The anode has a maximum inner diameter side facing the film formation substrate, and the plasma wall has a cylindrical shape or a polygonal shape, and the cylinder or the multi-angle is inside. Less than 100mm, 200mm or less, and the cathode is held in the holding portion of the distance between the deposition substrate is above 200mm, 300mm or less, The raw material gas is plasmad by discharging between the cathode and the anode. A slurry chemical vapor deposition apparatus according to claim 1, further comprising a magnet for generating a magnetic force in a region where the material gas is plasmaized, wherein the magnet has a cylindrical shape or a polygonal shape, and The magnetic force at the center of the magnet at the center of the inner diameter of the cylinder or the polygonal corner is 50 gauss or more and 200 gauss or less. The plasma chemical vapor deposition apparatus according to claim 2, wherein the magnet is disposed outside the cathode and the anode, and is disposed to surround the cathode and the anode. A plasma chemical vapor deposition apparatus according to claim 2 or 3, wherein the distance between the center of the magnet and the cathode is within 50 mm. A plasma chemical vapor deposition apparatus according to claim 2 or 3, wherein the magnet is a neodymium magnet. A method of manufacturing a magnetic recording medium using a plasma chemical vapor deposition apparatus according to any one of claims 1 to 5, characterized in that it is to be on a non-magnetic substrate The film formation substrate on which at least the magnetic layer is formed is held by the holding portion, and the material gas is formed into a plasma by discharge between the filament cathode and the anode heated under vacuum in the chamber. In a state, the plasma is accelerated and held by the surface of the film formation substrate of the holding portion to form a protective layer mainly composed of carbon. The method of producing a magnetic recording medium according to the sixth aspect of the invention, wherein the raw material gas system is configured to form a source gas of a DLC layer as the protective layer on the film formation substrate, and includes a gas containing carbon and hydrogen.