JP2014025114A - Plasma cvd apparatus, method of manufacturing magnetic recording medium and film deposition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma CVD apparatus capable of suppressing mutual interference of plasma even when the plasma is generated on both sides of a substrate to have a film deposited.SOLUTION: The plasma CVD apparatus includes: first and second anodes and first and second cathodes disposed inside a chamber; a holding part for holding a substrate; an AC power source connected to the first and second cathodes; a gas supply mechanism; an exhaust mechanism; and a control part which executes control so as to apply a second voltage to one of the first and second anodes while applying a first voltage to the other one of the first and second anodes by a DC power source at a first timing, and apply the first voltage to one of the first and second anodes while applying the second voltage to the other one of the first and second anodes by the DC power source at a second timing. The second voltage is greater than 0 V, and the first voltage is greater than the second voltage.

Description

  The present invention relates to a plasma CVD apparatus for forming films on both sides of a substrate, a method for manufacturing a magnetic recording medium, and a film forming method.

  In the conventional plasma CVD apparatus, ion sources are arranged on both sides of a film formation substrate in a chamber, and a high frequency voltage is applied to these ion sources by a plasma power source of a high frequency pulse, so that the source gas is in a plasma state in the chamber. As an apparatus for performing both-side film formation by accelerating and colliding with both surfaces of the film formation substrate. When plasma is generated on both sides of the deposition substrate in this way, the plasmas interfere with each other and it is difficult to form a film with good in-plane uniformity. Therefore, as a plasma CVD apparatus for realizing a film forming method in which mutual interference of plasma is suppressed, the apparatus shown in FIG. 7 has been proposed.

  As shown in FIG. 7, the plasma CVD apparatus includes a processing chamber 10 and a substrate holder 12 having an electrical connection 11 to a bias voltage 8 via a switch 9. The substrate holder 12 supports the substrate 14 in the processing chamber 10. The ion sources 20 and 22 are disposed on both sides of the substrate 14. The processing chamber 10 is conductive and grounded. An electrical bias is applied to the substrate 14 as needed during processing.

  The ion source 20 includes an anode 30 and an electron source. The electron source includes a filament 32 located near the anode 30 and a filament power source 34 connected to the filament 32. The ion source 22 includes an electron source comprising an anode 40 and a filament 42 located in the vicinity of the anode 40 and a filament power source 44 connected to the filament 42. The filament power sources 34 and 44 electrically heat the filaments 32 and 42, respectively, to generate electrons in the ion sources 20 and 22, respectively. Filaments 32 and 42 function as cathodes for the respective ion sources. The anodes 30 and 40 are connected to a power source 50 for energizing the respective ion sources 20 and 22 as described below.

  A gas source 54 supplies process gas to the process chamber 10. In particular, the gas source 54 supplies gas to each of the ion sources 20 and 22 in the region between the anodes 30 and 40 and the substrate 14.

  Gas is evacuated from the chamber 10 by a vacuum pump 60 connected to the chamber. Gas source 54 and vacuum pump 60 allow control of gas flow rate and pressure within chamber 10.

  In operation, each of the ion sources 20, 22 ionizes the process gas to form process gas ions. Ions are directed to the substrate 14 for deposition or etching. When the ion sources 20 and 22 are energized, plasma is generated in the vicinity of the anodes 30 and 40 in the processing chamber. The filaments 32 and 42 are supplied with electrons for ionization of process gas molecules in the plasma. Ions cross the plasma sheath on the substrate surface and are accelerated to the substrate surface of the substrate 14. The plasma CVD apparatus of FIG. 7 enables simultaneous processing on both sides of the substrate 14.

  In the plasma CVD apparatus of FIG. 7, the ion sources 20 and 22 are energized by a time multiplexing method synchronized so that only one of the anodes is always energized. In particular, the multiplexed voltage is applied to the anodes 30 and 40 of the ion sources 20 and 22. As shown in FIG. 8, the voltages at the anodes 30 and 40 are shown as a function of time. When the energizing voltage is time T1, T3, T5, it is applied to the anode 30, and when the energizing voltage is time T2, T4, it is applied to the anode 40. The voltages applied to the anodes 30, 40 do not overlap in time, so that only one of the ion sources is always energized. The ion source is alternately turned on and off, and the interaction of ions and plasma electrons between the ion source is removed. Electrons are collected alternately by one anode and the other. Synchronized or time multiplexed operations eliminate the need for complex shields or grids to electrically isolate one plasma from the other.

  The alternating voltage applied to the anodes 30, 40 preferably has a frequency from about 1 kHz to less than about 100 kHz. In general, the frequency of the anode voltage should be low compared to the number of ion reactions in the ion source 20,22. This ensures that the ion source switches on and off more rapidly than when the anode voltage is on and off (see, for example, Patent Document 1).

  As a power source 50 for applying a high frequency voltage of 1 kHz to 100 kHz to the anodes 30 and 40 of the plasma CVD apparatus shown in FIG. 7, a DC plasma power source that can use high frequency pulses is usually used. However, the DC plasma power supply tends to be expensive because it requires advanced technology to produce.

  Further, in the plasma CVD apparatus shown in FIG. 7, it is necessary to further provide a phase shifter for shifting the phase of the voltage applied to the anode as shown in FIG. 8, but this phase shifter is expensive.

Patent 3930185 (FIGS. 1 and 2)

An object of one embodiment of the present invention is to provide a plasma CVD apparatus, a method for manufacturing a magnetic recording medium, or a film forming method that can suppress plasma mutual interference even when plasma is generated on both sides of a deposition target substrate.
Another object of one embodiment of the present invention is to provide a plasma CVD apparatus, a method for manufacturing a magnetic recording medium, or a film formation method that can suppress plasma mutual interference at a lower cost.

Hereinafter, various aspects of the present invention will be described.
(1) a chamber;
First and second anodes disposed in the chamber;
First and second cathodes disposed in the chamber;
A holding unit for holding a deposition target substrate disposed in the chamber;
A first DC power source electrically connected to the first and second anodes;
An alternating current power source electrically connected to the first and second cathodes;
A gas supply mechanism for supplying a source gas into the chamber;
An exhaust mechanism for exhausting the chamber;
At a first timing, a second voltage is applied to the other of the first and second anodes while a first voltage is applied to one of the first and second anodes by the first DC power source. The second voltage is applied to the other one of the first and second anodes while the second voltage is applied to one of the first and second anodes by the first DC power source at a second timing. A control unit for controlling to apply
Comprising
One surface of the film formation substrate is disposed so as to face the first anode and the first cathode, and the other surface of the film formation substrate is the second anode and the second cathode. Arranged to face
The plasma CVD apparatus, wherein the second voltage is greater than 0V, and the first voltage is greater than the second voltage.

  According to the plasma CVD apparatus described above, strong plasma is always generated only on one side of the deposition target substrate and weak plasma is generated on the other side of the deposition target substrate 1. it can.

(2) In (1) above,
The control unit repeats the first timing and the second timing at a frequency in a range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz).

  According to the plasma CVD apparatus of (2) above, the plasma CVD apparatus can be manufactured at a lower cost.

(3) In (1) above,
The control unit repeats the first timing and the second timing at a frequency in a range of 10 Hz to 100 Hz,
The plasma CVD apparatus, wherein the control unit includes a sequencer, and the frequency is controlled by the sequencer.
(4) In any one of (1) to (3) above,
The controller does not apply the first voltage to both the first and second anodes simultaneously, and applies the second voltage to both the first and second anodes simultaneously. A plasma CVD apparatus which is controlled so as not to have any.

(5) In (1) above,
The control unit has a third timing between the first timing and the second timing, and the first and second anodes by the first DC power source at the third timing. The plasma CVD apparatus is controlled to apply the first voltage to both.

  According to the plasma CVD apparatus of the above (5), mutual plasma interference is provided by providing a timing for generating strong plasma on one side of the deposition substrate and generating weak plasma on the other side of the deposition substrate 1. Can be suppressed.

(6) a chamber;
First and second anodes disposed in the chamber;
First and second cathodes disposed in the chamber;
A holding unit for holding a deposition target substrate disposed in the chamber;
A first DC power source electrically connected to the first and second anodes;
An alternating current power source electrically connected to the first and second cathodes;
A gas supply mechanism for supplying a source gas into the chamber;
An exhaust mechanism for exhausting the chamber;
At a first timing, a second voltage is applied to the other of the first and second anodes while a first voltage is applied to one of the first and second anodes by the first DC power source. The second voltage is applied to the other one of the first and second anodes while the second voltage is applied to one of the first and second anodes by the first DC power source at a second timing. A control unit for controlling to apply
Comprising
One surface of the film formation substrate is disposed so as to face the first anode and the first cathode, and the other surface of the film formation substrate is the second anode and the second cathode. Arranged to face
The second voltage is 0V, the first voltage is greater than the second voltage;
The control unit has a third timing between the first timing and the second timing, and the first and second anodes by the first DC power source at the third timing. The plasma CVD apparatus is controlled to apply the first voltage to both.

  According to the plasma CVD apparatus of (6), it is possible to suppress the mutual interference of plasma by providing a timing for generating plasma only on one side of the deposition target substrate.

(7) In the above (5) or (6),
The control unit repeats the first timing, the third timing, the second timing, and the third timing at a frequency in a range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz). Plasma CVD apparatus.
(8) In the above (5) or (6),
The controller repeats the first timing, the third timing, the second timing, and the third timing at a frequency in the range of 10 Hz to 100 Hz,
The plasma CVD apparatus, wherein the control unit includes a sequencer, and the frequency is controlled by the sequencer.

(9) In any one of (1) to (8) above,
The plasma CVD apparatus, wherein the second voltage is 1 to 50% (preferably 10 to 30%) of the first voltage.

(10) a chamber;
First and second anodes disposed in the chamber;
First and second cathodes disposed in the chamber;
A holding unit for holding a deposition target substrate disposed in the chamber;
A first DC power source electrically connected to the first and second anodes;
An alternating current power source electrically connected to the first and second cathodes;
A gas supply mechanism for supplying a source gas into the chamber;
An exhaust mechanism for exhausting the chamber;
At a first timing, a second voltage is applied to the other of the first and second anodes while a first voltage is applied to one of the first and second anodes by the first DC power source. The second voltage is applied to the other one of the first and second anodes while the second voltage is applied to one of the first and second anodes by the first DC power source at a second timing. A control unit for controlling to apply
Comprising
One surface of the film formation substrate is disposed so as to face the first anode and the first cathode, and the other surface of the film formation substrate is the second anode and the second cathode. Arranged to face
The second voltage is 0V, the first voltage is greater than the second voltage;
The control unit repeats the first timing and the second timing at a frequency in a range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz).

  According to the plasma CVD apparatus of (10), plasma is not generated simultaneously on both sides of the film formation substrate, and plasma is always generated only on one side of the film formation substrate, so that mutual interference of plasma is suppressed. can do. Furthermore, since voltage application is performed at a frequency in the range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz), a plasma CVD apparatus can be manufactured at a lower cost.

(11) In any one of the above (1) to (10),
A first electrode disposed in the chamber and covering the space between the film formation substrate held by the holding portion and the first anode and the first cathode is set to a float potential. 1 plasma wall,
A first electrode disposed in the chamber and covering the space between the deposition target substrate held by the holding portion and the second anode and the second cathode and having a float potential. A plasma CVD apparatus comprising: 2 plasma walls.

(12) In any one of the above (1) to (11),
A plasma CVD apparatus comprising a third DC power source electrically connected to the deposition target substrate held by the holding unit.

(13) In the method for manufacturing a magnetic recording medium using the plasma CVD apparatus according to any one of (1) to (12),
Holding the film formation substrate on which at least the magnetic layer is formed on the nonmagnetic substrate in the holding unit,
In the chamber, the source gas is put into a plasma state by discharge between the first and second cathodes and the first and second anodes, respectively, and the film is formed by holding the plasma in the holding unit. A method for producing a magnetic recording medium, comprising forming a protective layer comprising carbon as a main component by accelerated collision with a surface of a substrate.

(14) In a film forming method for forming a film on a substrate using a plasma CVD apparatus having first and second anodes and first and second cathodes arranged in a chamber,
The substrate is placed in the chamber such that one surface thereof faces the first anode and the first cathode, and the other surface faces the second anode and the second cathode. And place
By applying a second voltage to the other of the first and second anodes while applying a first voltage to one of the first and second anodes at a first timing, A source gas is made into a plasma state and accelerated to collide with the substrate to form a film,
Applying the first voltage to the other of the first and second anodes while applying the second voltage to one of the first and second anodes at a second timing; The source gas is in a plasma state and acceleratedly collided with the substrate to form a film,
AC voltage is applied to the first and second cathodes at the first and second timings,
The film forming method, wherein the second voltage is greater than 0 V, and the first voltage is greater than the second voltage.

(15) In the above (14),
The film formation method characterized by repeating the first timing and the second timing at a frequency in a range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz).
(16) In the above (14),
The control unit repeats the first timing and the second timing at a frequency in a range of 10 Hz to 100 Hz,
The film forming method, wherein the control unit includes a sequencer, and the frequency is controlled by the sequencer.

(17) In the above (14),
There is a third timing between the first timing and the second timing, and an AC voltage is applied to the first and second cathodes at the third timing, and the first and second timings A film forming method, wherein the first voltage is applied to both of the second anodes to cause the source gas to be accelerated and collide with the substrate in a plasma state in the chamber.

(18) In a film forming method for forming a film on a substrate using a plasma CVD apparatus having first and second anodes and first and second cathodes arranged in a chamber,
The substrate is placed in the chamber such that one surface thereof faces the first anode and the first cathode, and the other surface faces the second anode and the second cathode. And place
By applying a second voltage to the other of the first and second anodes while applying a first voltage to one of the first and second anodes at a first timing, A source gas is made into a plasma state and accelerated to collide with the substrate to form a film,
At the third timing, by applying the first voltage to both the first and second anodes, the source gas is caused to accelerate and collide with the substrate in a plasma state in the chamber;
Applying the first voltage to the other of the first and second anodes while applying the second voltage to one of the first and second anodes at a second timing; The source gas is in a plasma state and acceleratedly collided with the substrate to form a film,
AC voltage is applied to the first and second cathodes at the first to third timings,
The film forming method, wherein the second voltage is 0 V, and the first voltage is larger than the second voltage.

(19) In the above (17) or (18),
The film formation method characterized by repeating the first timing, the third timing, the second timing, and the third timing at a frequency in the range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz). .
(20) In the above (17) or (18),
The controller repeats the first timing, the third timing, the second timing, and the third timing at a frequency in the range of 10 Hz to 100 Hz,
The film forming method, wherein the control unit includes a sequencer, and the frequency is controlled by the sequencer.

(21) In any one of the above (14) to (20),
The film forming method, wherein the second voltage is 1 to 50% (preferably 10 to 30%) of the first voltage.

(22) In a film forming method for forming a film on a substrate using a plasma CVD apparatus having first and second anodes and first and second cathodes arranged in a chamber,
The substrate is placed in the chamber such that one surface thereof faces the first anode and the first cathode, and the other surface faces the second anode and the second cathode. And place
By applying a second voltage to the other of the first and second anodes while applying a first voltage to one of the first and second anodes at a first timing, A source gas is made into a plasma state and accelerated to collide with the substrate to form a film,
Applying the first voltage to the other of the first and second anodes while applying the second voltage to one of the first and second anodes at a second timing; The source gas is in a plasma state and acceleratedly collided with the substrate to form a film,
AC voltage is applied to the first and second cathodes at the first and second timings,
The second voltage is 0V, the first voltage is greater than the second voltage;
The film formation method characterized by repeating the first timing and the second timing at a frequency in a range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz).

(23) In a method for manufacturing a magnetic recording medium, in which a protective layer mainly composed of carbon is formed after forming at least a magnetic layer on a nonmagnetic substrate.
A method for producing a magnetic recording medium, comprising forming a protective layer by the film forming method according to any one of (14) to (22).

According to one embodiment of the present invention, it is possible to provide a plasma CVD apparatus, a method for manufacturing a magnetic recording medium, or a film forming method that can suppress plasma mutual interference even when plasma is generated on both sides of a film formation substrate.
Further, according to one embodiment of the present invention, a plasma CVD apparatus, a method for manufacturing a magnetic recording medium, or a film formation method that can suppress mutual interference of plasma can be provided at a lower cost.

It is sectional drawing which shows typically the plasma CVD apparatus which concerns on 1 aspect of this invention. (A) is a relationship between the voltage applied to the first anode electrode 104a and time, (B) is a timing chart by the first control showing the relationship between the voltage applied to the second anode electrode 104b and time, C is a timing chart by the second control showing the relationship between the voltage applied to the second anode electrode 104b and time, and (D) is the relationship between the voltage applied to the first anode electrode 104a and time. (A) is the relationship between the voltage applied to the second anode electrode 104b and time, (B) is a timing chart by the third control showing the relationship between the voltage applied to the first anode electrode 104a and time, ( (C) is a relationship between the voltage applied to the second anode electrode 104b and time, and (D) is a timing chart by the fourth control showing the relationship between the voltage applied to the first anode electrode 104a and time. (A) is a photograph of the DLC film 10 formed on the film formation substrate 1 using the plasma processing apparatus shown in FIG. 1, and (B) is a DLC film formed on the film formation substrate 1 shown in (A). 2 is a cross-sectional view schematically showing the film thickness of a film 10. FIG. (A) is a photograph of the DLC film 11 formed on the film formation substrate 1 using the plasma processing apparatus shown in FIG. 1, and (B) is a DLC film formed on the film formation substrate 1 shown in (A). 3 is a cross-sectional view schematically showing the film thickness of a film 11. FIG. (A) is a timing chart showing the relationship between the voltage applied to the first anode cone 104a and time, and (B) is a timing chart showing the relationship between the voltage applied to the second anode cone 104b and time. It is a block diagram which shows the conventional plasma CVD apparatus typically. It is a timing chart which shows the relationship between the voltage applied to the anode of the plasma CVD apparatus shown in FIG. 7, and time.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

<Plasma CVD equipment>
FIG. 1 is a cross-sectional view schematically illustrating a plasma CVD apparatus according to one embodiment of the present invention. This plasma CVD apparatus has a symmetrical structure with respect to a film formation substrate (for example, a disk substrate) 1 and is an apparatus capable of forming films on both surfaces of the film formation substrate 1 simultaneously.

  The plasma CVD apparatus includes a chamber 102, and filament-shaped first and second cathode electrodes (first and second cathode filaments) 103a and 103b made of, for example, tantalum are formed in the chamber 102. ing. Both ends of each of the first and second cathode filaments 103a and 103b are electrically connected to first and second cathode power sources (first and second AC power sources) 105a and 105b located outside the chamber 102. The first and second cathode power supplies 105 a and 105 b are arranged in an insulated state with respect to the chamber 102. As the first and second cathode power supplies 105a and 105b, for example, power supplies of 0 to 50 V and 10 to 50 A (ampere) can be used. One ends of the first and second cathode power supplies 105 a and 105 b are electrically connected to the ground 106.

  In the chamber 102, first and second anode electrodes (first and second anode cones) 104a having funnel-like shapes so as to surround the first and second cathode filaments 103a and 103b, respectively. 104b is disposed, and each of the first and second anode cones 104a and 104b is shaped like a speaker.

  The first anode cone 104 a is electrically connected to a first anode power source (first DC (direct current) power source) 107 a via a first switch 121 a, and the first DC power source 107 a is connected to the chamber 102. It is arranged in an insulated state. The positive potential side of the first DC power source 107a is electrically connected to the first anode cone 104a via the first switch 121a, and the negative potential side of the first DC power source 107a is electrically connected to the ground 106. Has been.

  The second anode cone 104b is electrically connected to a second anode power source (second DC (direct current) power source) 107b via a second switch 121b, and the second DC power source 107b is connected to the chamber 102. It is arranged in an insulated state. The positive potential side of the second DC power source 107b is electrically connected to the second anode cone 104b via the second switch 121b, and the negative potential side of the second DC power source 107b is electrically connected to the ground 106. Has been.

  The first and second switches 121a and 121b and the first and second DC power sources 107a and 107b are controlled by a control unit (not shown). Thereby, the voltages applied to the first and second anode cones 104a and 104b are controlled. As the first and second DC power sources 107a and 107b, for example, power sources of 0 to 500 V and 0 to 7.5 A (ampere) can be used.

  Said control part performs the following 1st-4th control, for example. The control unit may have a sequencer.

[First control: FIGS. 2A and 2B]
In the first control, a second voltage is applied to the other of the first and second anodes while applying a first voltage to one of the first and second anodes by a first DC power source at a first timing. A voltage is applied, and the second voltage is applied to one of the first and second anodes by the first DC power source at a second timing, while the second voltage is applied to the other of the first and second anodes. Control is performed so that a first voltage is applied, and the first timing and the second timing are repeated at a frequency in the range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz). The second voltage is 0V, and the first voltage is greater than the second voltage.

This will be specifically described below.
FIG. 2A is a timing chart showing the relationship between the voltage applied to the first anode electrode 104a and time, and FIG. 2B shows the relationship between the voltage applied to the second anode electrode 104b and time. It is a timing chart which shows.

  The first control is the first anode electrode by the first and second DC power sources 107a and 107b at the first timing of 0.00 to 0.02 seconds shown in FIGS. While applying a first voltage of 0V to 104a, a second voltage of 75V is applied to the second anode electrode 104b for 0.02 to 0.04 seconds as shown in FIGS. At the second timing, the first and second DC power sources 107a and 107b apply the second voltage 75V to the first anode electrode 104a while applying the first voltage to the second anode electrode 104b. A certain 0 V is applied, and the first timing and the second timing are repeated at a frequency in the range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz). Note that the sequencer preferably performs frequency control, and the frequency in that case is preferably in the range of 10 to 100 Hz.

  According to the first control described above, plasma is not generated simultaneously on both sides of the deposition target substrate 1, and plasma is always generated only on one side of the deposition target substrate 1, thereby suppressing plasma mutual interference. can do. Therefore, a film can be formed with good in-plane uniformity. Furthermore, since voltage application is performed at a frequency in the range of 10 Hz to 400 kHz, the plasma CVD apparatus can be manufactured at a lower cost.

[Second Control: FIGS. 2C and 2D]
In the second control, the first voltage is applied to one of the first and second anodes by the first DC power source at the first timing, while the second voltage is applied to the other of the first and second anodes. A voltage is applied, and the second voltage is applied to one of the first and second anodes by the first DC power source at a second timing while the second voltage is applied to the other of the first and second anodes. Control is performed so as to apply the first voltage. The second voltage is greater than 0V and the first voltage is greater than the second voltage. Note that the second voltage is preferably 1 to 50% (preferably 10 to 30%) of the first voltage.

  In the second control, the first timing and the second timing are preferably repeated at a frequency in a range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz), and the first and second anodes are repeated. Preferably, the first voltage is not applied to both of the first and second anodes, and the second voltage is not applied to both the first and second anodes simultaneously.

This will be specifically described below.
2C is a timing chart showing the relationship between the voltage applied to the second anode electrode 104b and time, and FIG. 2D shows the relationship between the voltage applied to the first anode electrode 104a and time. It is a timing chart which shows.

  In the second control, the first anode electrode is supplied by the first and second DC power sources 107a and 107b at the first timing of 0.00 to 0.02 seconds shown in FIGS. While applying the first voltage of 75V to 104a, the second voltage of 10V is applied to the second anode electrode 104b for 0.02 to 0.04 seconds as shown in FIGS. At the second timing, the first and second DC power sources 107a and 107b apply the second voltage of 10V to the first anode electrode 104a while applying the first voltage to the second anode electrode 104b. A certain 75 V is applied, and the first timing and the second timing are repeated at a frequency in the range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz). Note that the sequencer preferably performs frequency control, and the frequency in that case is preferably in the range of 10 to 100 Hz.

  According to the second control, a strong plasma is always generated only on one side of the deposition target substrate 1 and a weak plasma is generated on the other side of the deposition target substrate 1. be able to. Therefore, a film can be formed with good in-plane uniformity. Moreover, since voltage application is performed at a frequency in the range of 10 Hz to 400 kHz, the plasma CVD apparatus can be manufactured at a lower cost.

[Third Control: FIGS. 3A and 3B]
In the third control, the first voltage is applied to the other of the first and second anodes while applying the first voltage to one of the first and second anodes by the first DC power source at the first timing. 2 and applying the second voltage to one of the first and second anodes by the first DC power source at the second timing, while the other of the first and second anodes is applied. The first voltage is applied to the first timing, and a third timing is provided between the first timing and the second timing, and the first DC power source is used for the first timing at the third timing. And controlling to apply the first voltage to both the second anode and the second anode. The second voltage is 0V, and the first voltage is greater than the second voltage. Note that the second voltage is preferably 1 to 50% (preferably 10 to 30%) of the first voltage.

  In the second control, the first timing, the third timing, the second timing, and the third timing are repeated at a frequency in the range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz). It is preferable.

This will be specifically described below.
FIG. 3A is a timing chart showing the relationship between the voltage applied to the second anode electrode 104b and time, and FIG. 3B shows the relationship between the voltage applied to the first anode electrode 104a and time. It is a timing chart which shows.

  The third control is the first anode electrode by the first and second DC power sources 107a and 107b at the first timing of 0.01 to 0.02 seconds shown in FIGS. While applying a first voltage of 75V to 104a, a second voltage of 0V is applied to the second anode electrode 104b, and 0.02 to 0.03 seconds shown in FIGS. 3 (A) and 3 (B). At the third timing, 75V, which is the first voltage, is applied to both the first and second anode electrodes 104a, 104b by the first and second DC power sources 107a, 107b, and FIG. , (B), a second voltage of 0 V is applied to the first anode electrode 104a by the first and second DC power sources 107a and 107b at the second timing of 0.03 to 0.04 seconds. While the second anode electrode 104b The first and second DC power supplies 107a and 107b are applied at the third timing of 0.04 to 0.05 seconds shown in FIGS. 3 (A) and 3 (B). 75V, which is the first voltage, is applied to both the second anode electrode 104a and the second anode electrode 104b, and the first timing, the third timing, the second timing, and the third timing are set to 10 Hz or more and 400 kHz. It repeats at a frequency in the following range (preferably 10 Hz or more and less than 1 kHz). Note that the sequencer preferably performs frequency control, and the frequency in that case is preferably in the range of 10 to 100 Hz.

  According to the third control, it is possible to suppress the mutual interference of plasma by providing a timing for generating plasma only on one side of the deposition target substrate 1. Therefore, a film can be formed with good in-plane uniformity. Moreover, since voltage application is performed at a frequency in the range of 10 Hz to 400 kHz, the plasma CVD apparatus can be manufactured at a lower cost.

[Fourth Control: FIGS. 3C and 3D]
In the fourth control, the first voltage is applied to the other one of the first and second anodes while the first voltage is applied to one of the first and second anodes by the first DC power source at the first timing. 2 and applying the second voltage to one of the first and second anodes by the first DC power source at the second timing, while the other of the first and second anodes is applied. The first voltage is applied to the first timing, and a third timing is provided between the first timing and the second timing, and the first DC power source is used for the first timing at the third timing. And controlling to apply the first voltage to both the second anode and the second anode. The second voltage is greater than 0V and the first voltage is greater than the second voltage. Note that the second voltage is preferably 1 to 50% (preferably 10 to 30%) of the first voltage.

  In the second control, the first timing, the third timing, the second timing, and the third timing are repeated at a frequency in the range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz). It is preferable.

This will be specifically described below.
FIG. 3C is a timing chart showing the relationship between the voltage applied to the second anode electrode 104b and time, and FIG. 3D shows the relationship between the voltage applied to the first anode electrode 104a and time. It is a timing chart which shows.

  The fourth control is the first anode electrode by the first and second DC power sources 107a and 107b at the first timing of 0.01 to 0.02 seconds shown in FIGS. While applying 75V as the first voltage to 104a, 10V as the second voltage is applied to the second anode electrode 104b, and 0.02 to 0.03 seconds shown in FIGS. 3 (C) and 3 (D). At the third timing, the first and second DC power sources 107a and 107b apply the first voltage of 75 V to both the first and second anode electrodes 104a and 104b, and FIG. ) And (D) at the second timing of 0.03 to 0.04 seconds, the first and second DC power supplies 107a and 107b apply a second voltage of 10V to the first anode electrode 104a. The second anode electrode 10 while applying The first and second DC power sources 107a and 107a are applied to b at a third timing of 0.04 to 0.05 seconds shown in FIGS. A first voltage 75V is applied to both the first and second anode electrodes 104a and 104b by 107b, and the first timing, the third timing, the second timing, and the third timing are applied. Is repeated at a frequency in the range of 10 Hz to 400 kHz (preferably 10 Hz to less than 1 kHz). Note that the sequencer preferably performs frequency control, and the frequency in that case is preferably in the range of 10 to 100 Hz.

  According to the fourth control described above, by providing a timing at which strong plasma is generated on one side of the deposition target substrate 1 and weak plasma is generated on the other side of the deposition target substrate 1, plasma mutual interference is achieved. Can be suppressed. Therefore, a film can be formed with good in-plane uniformity. Moreover, since voltage application is performed at a frequency in the range of 10 Hz to 400 kHz, the plasma CVD apparatus can be manufactured at a lower cost.

  A deposition target substrate 1 is disposed in the chamber 102, and this deposition target substrate 1 is opposed to the first and second cathode filaments 103a and 103b and the first and second anode cones 104a and 104b. Are arranged. Specifically, the first and second cathode filaments 103a and 103b are surrounded near the center of the inner peripheral surface of the first and second anode cones 104a and 104b, and the first and second anode cones 104a are surrounded. , 104b are arranged with the maximum inner diameter side facing the film formation substrate 1.

  The deposition target substrate 1 is sequentially supplied to the positions shown by a holder (holding unit) not shown and a transfer device (handling robot or rotary index table) not shown.

  The deposition target substrate 1 is electrically connected to a bias power source (DC power source, DC power source) 112 as a power source for accelerating ions, and the DC power source 112 is arranged in an insulated state with respect to the chamber 102. . The negative potential side of the DC power source 112 is electrically connected to the deposition target substrate 1, and the positive potential side of the DC power source 112 is electrically connected to the ground 106. As the DC power source 112, for example, a power source of 0 to 1500 V and 0 to 100 mA (milliampere) can be used.

  A first plasma wall 108 a is disposed in the chamber 102 so as to cover the space between the first cathode filament 103 a and the first anode cone 104 a and the deposition target substrate 1, and the second cathode A second plasma wall 108b is disposed so as to cover the space between each of the filament 103b and the second anode cone 104b and the deposition target substrate 1.

  Each of the first and second plasma walls 108 a and 108 b is electrically connected to a float potential (not shown), and is disposed in an insulated state with respect to the chamber 102. The first and second plasma walls 108a and 108b have a cylindrical shape or a polygonal shape.

  Film thickness correction plates 118a and 118b are provided at the ends of the first and second plasma walls 108a and 108b on the film formation substrate 1 side, and the film thickness correction plates 118a and 118b are electrically connected to the float potential. Connected. The thickness of the film formed on the outer peripheral portion of the deposition target substrate 1 can be controlled by the film thickness correction plates 118a and 118b.

  First and second neodymium magnets 109 a and 109 b are disposed outside the chamber 102. The first and second neodymium magnets 109a and 109b have, for example, a cylindrical shape or a polygonal shape, and the center of the cylindrical or polygonal inner diameter is the magnet center, and the magnet center is the first and second cathode filaments. They are positioned so as to face the approximate centers of 103a and 103b and the approximate center of the deposition target substrate 1, respectively. Each of the first and second neodymium magnets 109a and 109b preferably has a magnetic force of 50G (Gauss) or more and 200G or less, more preferably 50G or more and 150G or less. The reason why the magnetic force at the magnet center is set to 200 G or less is that in the case of a neodymium magnet, it is a manufacturing limit to increase the magnetic force at the magnet center to 200 G. The reason why the magnetic force at the center of the magnet is preferably 150 G or less is that if the magnetic force at the center of the magnet exceeds 150 G, the cost of making the magnet increases.

  In addition, the plasma CVD apparatus has an evacuation mechanism (not shown) for evacuating the chamber 102. In addition, the plasma CVD apparatus has a gas supply mechanism (not shown) for supplying a film forming material gas into the chamber 102.

<Film formation method>
A method of forming a DLC (Diamond Like Carbon) film on the deposition target substrate 1 using the plasma CVD apparatus shown in FIG. 1 will be described.

First, the vacuum evacuation mechanism is activated, the inside of the chamber 102 is brought into a predetermined vacuum state, and, for example, toluene (C ₇ H ₈ ) gas is introduced into the chamber 102 as a film forming source gas by the gas introduction mechanism. After the chamber 102 reaches a predetermined pressure, the first and second cathode power sources 105a and 105b supply alternating currents to the first and second cathode filaments 103a and 103b, respectively. The cathode filaments 103a and 103b are heated.

  Further, a direct current is supplied to the deposition target substrate 1 by a DC power source 112. Further, a direct current is supplied from the first and second DC power sources 107a and 107b to the first and second anode cones 104a and 104b via the first and second switches 121a and 121b, respectively. At this time, the voltage applied to each of the first and second anode cones 104a and 104b is controlled by the control unit according to the first control shown in FIGS. 2 (A) and 2 (B). The second control shown in (D), the third control shown in FIGS. 3 (A) and 3 (B), or the fourth control shown in FIGS. 3 (C) and 3 (D). .

  By heating the first and second cathode filaments 103a and 103b, a large amount of electrons are emitted from the first and second cathode filaments 103a and 103b toward the first and second anode cones 104a and 104b, respectively. Glow discharge is started between each of the first and second cathode filaments 103a and 103b and each of the first and second anode cones 104a and 104b. Toluene gas as a film forming raw material gas inside the chamber 102 is ionized by a large amount of electrons to be in a plasma state. At this time, since the first and second neodymium magnets 109a and 109b respectively generate magnetic fields in regions where the toluene gas located in the vicinity of the first and second cathode filaments 103a and 103b is turned into plasma, Plasma can be densified by a magnetic field, and ionization efficiency can be improved. The deposition raw material molecules in the plasma state are directly accelerated by the negative potential of the deposition target substrate 1, fly toward the deposition target substrate 1, and adhere to the surface of the deposition target substrate 1. Is done. Thereby, a thin DLC film is formed on the deposition target substrate 1. At this time, the reaction of the following formula (1) occurs on the surface of the film formation substrate 1.

C ₇ H ₈ + e ⁻ → C _a H _b + xH ₂ ↑ (1)

  Next, a method for 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 nonmagnetic substrate is prepared, and this film formation substrate is held by a holding unit. Next, the source gas is plasma-treated by discharge between the first and second cathode filaments 103a and 103b and the first and second anode cones 104a and 104b, respectively, heated in the chamber 102 under a predetermined vacuum condition. The plasma is accelerated and collided with the surface of the film formation substrate held by the holding unit. As a result, a protective layer mainly composed of carbon is formed on the surface of the film formation substrate.

  According to the above-described embodiment, even in the plasma CVD apparatus, the film forming method, and the magnetic recording medium manufacturing method in which the plasma is generated on both sides of the film formation substrate 1 to form the film on both surfaces of the film formation substrate 1. By suppressing the mutual interference of the plasma, the in-plane uniformity of the films formed on both surfaces of the deposition target substrate 1 can be improved.

Example 1
FIG. 4A is a photograph in which the DLC film 10 is formed on the deposition target substrate 1 using the plasma processing apparatus shown in FIG. 1, and FIG. 4B is the deposition shown in FIG. 1 is a cross-sectional view schematically showing the thickness of a DLC film 10 formed on a film substrate 1. FIG. FIG. 6A is a timing chart showing the relationship between the voltage applied to the first anode cone 104a and time, and FIG. 6B shows the relationship between the voltage applied to the second anode cone 104b and time. It is a timing chart which shows.

The conditions when the DLC film 10 shown in FIGS. 4A and 4B is formed are as follows.
Deposition apparatus: plasma CVD apparatus shown in FIG. 1 Deposition substrate 1: Glass disk with metal layer Starting material: High purity toluene Gas flow rate: 3.0 sccm
Pressure: 0.3 Pa
Deposition time: 2 sec × 5 times Cathode filament 103a, 103b: Tantalum filament Output from AC power supply 105a, 105b: 230W
Current of DC power supplies 107a and 107b: 1650 mA
DC power supply 107a, 107b voltage: maximum 95V, minimum 10V
Frequency: 20Hz
Voltage control to the first and second anode cones 104a and 104b: FIGS. 6 (A) and 6 (B)
Voltage of DC power supply 112: 250V

(Comparative Example 1)
FIG. 5A is a photograph in which the DLC film 11 is formed on the deposition target substrate 1 using the plasma processing apparatus shown in FIG. 1, and FIG. 5B is the deposition shown in FIG. 2 is a cross-sectional view schematically showing a film thickness of a DLC film 11 formed on a film substrate 1. FIG.

Conditions for forming the DLC film 11 shown in FIGS. 5A and 5B are as follows.
Deposition apparatus: plasma CVD apparatus shown in FIG. 1 Deposition substrate 1: Glass disk with metal layer Starting material: High purity toluene Gas flow rate: 3.0 sccm
Pressure: 0.3 Pa
Deposition time: 2 sec × 5 times Cathode filament 103a, 103b: Tantalum filament Output from AC power supply 105a, 105b: 230W
Current of DC power supplies 107a and 107b: 1650 mA
Voltage of DC power supply 107a, 107b: constant 95V Voltage of DC power supply 112: 250V

  In the above comparative example, as shown in FIG. 5B, the thickness of the DLC film 11 near the outer periphery of the deposition target substrate 1 is increased. ), The thickness of the DLC film 10 in the vicinity of the outer periphery of the deposition target substrate 1 became substantially constant. Therefore, it was confirmed that even if plasma was generated on both sides of the deposition target substrate 1, the mutual interference of the plasma could be suppressed.

DESCRIPTION OF SYMBOLS 1 Substrate to be deposited 10,11 DLC film 102 Chamber 103a First cathode electrode (first cathode filament)
103b Second cathode electrode (second cathode filament)
104a First anode electrode (first anode cone)
104b Second anode electrode (second anode cone)
105a First cathode power source (first AC power source)
105b Second cathode power source (second AC power source)
106 Ground power source 107a First anode power source (first DC (direct current) power source)
107b Second anode power source (second DC (direct current) power source)
108a First plasma wall 108b Second plasma wall 118a, 118b Film thickness correction plate 109a First neodymium magnet 109b Second neodymium magnet 112 Bias power source (DC power source, DC power source)
121a first switch 121b second switch

Claims (21)

A chamber;
First and second anodes disposed in the chamber;
First and second cathodes disposed in the chamber;
A holding unit for holding a deposition target substrate disposed in the chamber;
A first DC power source electrically connected to the first and second anodes;
An alternating current power source electrically connected to the first and second cathodes;
A gas supply mechanism for supplying a source gas into the chamber;
An exhaust mechanism for exhausting the chamber;
At a first timing, a second voltage is applied to the other of the first and second anodes while a first voltage is applied to one of the first and second anodes by the first DC power source. The second voltage is applied to the other one of the first and second anodes while the second voltage is applied to one of the first and second anodes by the first DC power source at a second timing. A control unit for controlling to apply
Comprising
One surface of the film formation substrate is disposed so as to face the first anode and the first cathode, and the other surface of the film formation substrate is the second anode and the second cathode. Arranged to face
The plasma CVD apparatus, wherein the second voltage is greater than 0V, and the first voltage is greater than the second voltage. In claim 1,
The said control part repeats the said 1st timing and the said 2nd timing with the frequency of the range of 10 Hz or more and 400 kHz or less, The plasma CVD apparatus characterized by the above-mentioned. In claim 1,
The control unit repeats the first timing and the second timing at a frequency in a range of 10 Hz to 100 Hz,
The plasma CVD apparatus, wherein the control unit includes a sequencer, and the frequency is controlled by the sequencer. In any one of Claims 1 thru | or 3,
The controller does not apply the first voltage to both the first and second anodes simultaneously, and applies the second voltage to both the first and second anodes simultaneously. A plasma CVD apparatus which is controlled so as not to have any. In claim 1,
The control unit has a third timing between the first timing and the second timing, and the first and second anodes by the first DC power source at the third timing. The plasma CVD apparatus is controlled to apply the first voltage to both. A chamber;
First and second anodes disposed in the chamber;
First and second cathodes disposed in the chamber;
A holding unit for holding a deposition target substrate disposed in the chamber;
A first DC power source electrically connected to the first and second anodes;
An alternating current power source electrically connected to the first and second cathodes;
A gas supply mechanism for supplying a source gas into the chamber;
An exhaust mechanism for exhausting the chamber;
At a first timing, a second voltage is applied to the other of the first and second anodes while a first voltage is applied to one of the first and second anodes by the first DC power source. The second voltage is applied to the other one of the first and second anodes while the second voltage is applied to one of the first and second anodes by the first DC power source at a second timing. A control unit for controlling to apply
Comprising
One surface of the film formation substrate is disposed so as to face the first anode and the first cathode, and the other surface of the film formation substrate is the second anode and the second cathode. Arranged to face
The second voltage is 0V, the first voltage is greater than the second voltage;
The control unit has a third timing between the first timing and the second timing, and the first and second anodes by the first DC power source at the third timing. The plasma CVD apparatus is controlled to apply the first voltage to both. In claim 5 or 6,
The said control part repeats the said 1st timing, the said 3rd timing, the said 2nd timing, and the said 3rd timing with the frequency of the range of 10 Hz or more and 400 kHz or less, The plasma CVD apparatus characterized by the above-mentioned. In claim 5 or 6,
The controller repeats the first timing, the third timing, the second timing, and the third timing at a frequency in the range of 10 Hz to 100 Hz,
The plasma CVD apparatus, wherein the control unit includes a sequencer, and the frequency is controlled by the sequencer. In any one of Claims 1 thru | or 8,
The plasma CVD apparatus, wherein the second voltage is 1 to 50% of the first voltage. In any one of Claims 1 thru | or 9,
A first electrode disposed in the chamber and covering the space between the film formation substrate held by the holding portion and the first anode and the first cathode is set to a float potential. 1 plasma wall,
A first electrode disposed in the chamber and covering the space between the deposition target substrate held by the holding portion and the second anode and the second cathode and having a float potential. A plasma CVD apparatus comprising: 2 plasma walls. In any one of Claims 1 thru | or 10,
A plasma CVD apparatus comprising a third DC power source electrically connected to the deposition target substrate held by the holding unit. In the manufacturing method of the magnetic-recording medium using the plasma CVD apparatus as described in any one of Claims 1 thru | or 11,
Holding the film formation substrate on which at least the magnetic layer is formed on the nonmagnetic substrate in the holding unit,
In the chamber, the source gas is put into a plasma state by discharge between the first and second cathodes and the first and second anodes, respectively, and the film is formed by holding the plasma in the holding unit. A method for producing a magnetic recording medium, comprising forming a protective layer comprising carbon as a main component by accelerated collision with a surface of a substrate. In a film forming method for forming a film on a substrate using a plasma CVD apparatus having first and second anodes and first and second cathodes disposed in a chamber,
The substrate is placed in the chamber such that one surface thereof faces the first anode and the first cathode, and the other surface faces the second anode and the second cathode. And place
By applying a second voltage to the other of the first and second anodes while applying a first voltage to one of the first and second anodes at a first timing, A source gas is made into a plasma state and accelerated to collide with the substrate to form a film,
Applying the first voltage to the other of the first and second anodes while applying the second voltage to one of the first and second anodes at a second timing; The source gas is in a plasma state and acceleratedly collided with the substrate to form a film,
AC voltage is applied to the first and second cathodes at the first and second timings,
The film forming method, wherein the second voltage is greater than 0 V, and the first voltage is greater than the second voltage. In claim 13,
The film forming method, wherein the first timing and the second timing are repeated at a frequency in a range of 10 Hz to 400 kHz. In claim 13,
The control unit repeats the first timing and the second timing at a frequency in a range of 10 Hz to 100 Hz,
The film forming method, wherein the control unit includes a sequencer, and the frequency is controlled by the sequencer. In claim 13,
There is a third timing between the first timing and the second timing, and an AC voltage is applied to the first and second cathodes at the third timing, and the first and second timings A film forming method, wherein the first voltage is applied to both of the second anodes to cause the source gas to be accelerated and collide with the substrate in a plasma state in the chamber. In a film forming method for forming a film on a substrate using a plasma CVD apparatus having first and second anodes and first and second cathodes disposed in a chamber,
The substrate is placed in the chamber such that one surface thereof faces the first anode and the first cathode, and the other surface faces the second anode and the second cathode. And place
By applying a second voltage to the other of the first and second anodes while applying a first voltage to one of the first and second anodes at a first timing, A source gas is made into a plasma state and accelerated to collide with the substrate to form a film,
At the third timing, by applying the first voltage to both the first and second anodes, the source gas is caused to accelerate and collide with the substrate in a plasma state in the chamber;
Applying the first voltage to the other of the first and second anodes while applying the second voltage to one of the first and second anodes at a second timing; The source gas is in a plasma state and acceleratedly collided with the substrate to form a film,
AC voltage is applied to the first and second cathodes at the first to third timings,
The film forming method, wherein the second voltage is 0 V, and the first voltage is larger than the second voltage. In claim 16 or 17,
The film forming method, wherein the first timing, the third timing, the second timing, and the third timing are repeated at a frequency in a range of 10 Hz to 400 kHz. In claim 16 or 17,
The controller repeats the first timing, the third timing, the second timing, and the third timing at a frequency in the range of 10 Hz to 100 Hz,
The film forming method, wherein the control unit includes a sequencer, and the frequency is controlled by the sequencer. In any one of claims 13 to 19,
The film forming method, wherein the second voltage is 1 to 50% of the first voltage. In a method for manufacturing a magnetic recording medium, in which a protective layer mainly composed of carbon is formed after forming at least a magnetic layer on a nonmagnetic substrate.
A method for manufacturing a magnetic recording medium, comprising forming a protective layer by the film forming method according to claim 13.