JPH08165196A - Diamond-like coating layer formation and equipment therefor - Google Patents

Abstract

PURPOSE: To provide a method and equipment for forming diamond-like coated film at increased film formation rate compared with the conventional process by increasing the reaction gas ionization efficiency and the neutralization properties without enlargement of the installation. CONSTITUTION: Arc discharge plasma flow 9 is generated toward the anode 19 arranged in the vacuum chamber 8 and a reaction gas containing carbon atoms is fed from the anode 19 into the arc discharge plasma flow 9. At the same time, a prescribed high-frequency voltage is applied to the base plate 16 arranged in the vacuum chamber 8 to form this diamond-like coated film on the base 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond-like film formed for the purpose of improving the characteristics of electric razor blades, semiconductor materials, magnetic heads, sliding parts of various devices, etc., and protecting the surface, and more particularly, The present invention relates to a method and an apparatus for forming a diamond-like coating by using an arc discharge plasma flow.

[0002]

2. Description of the Related Art Conventionally, an ion beam sputtering method, an ion plating method, a plasma CVD method and the like have been used as a diamond-like film forming method.

In recent years, ECR plasma CVD capable of forming a uniform film at a low temperature on a large area as compared with the conventional method.
The method has been proposed as disclosed in Japanese Patent Laid-Open No. 3-64468 and has already been put to practical use. This EC
The R plasma CVD method is a method in which electron cyclotron resonance is caused in an ECR ion source to generate high-density plasma, and a plasma flow is applied to a substrate by utilizing a divergent magnetic field to form a film.

However, the above ECR plasma CVD
In the method, the range in which the film can be formed is limited by the size of the plasma flow that irradiates the substrate, and thus there is a limit in increasing the area of the film.

For this reason, recently, the above ECR plasma C
As a film forming method capable of further increasing the area than the VD method, an ion plating method using an arc discharge plasma flow source is disclosed in JP-A-1-259163 and "Vacuum Vol. 25, No. 12, page 781-". Page 787 (published in 1982) ”and the like.

FIG. 5 shows a block diagram of this ion plating apparatus. Reference numeral 1 denotes a pressure gradient type plasma gun as an arc discharge plasma flow generation source, which includes a cathode 2, a first intermediate electrode 3, and a second intermediate electrode 4.

The first intermediate electrode 3 and the second intermediate electrode 4 are
The first intermediate electrode 3 contains a ring-shaped permanent magnet 6 and the second intermediate electrode 4 contains an air-core coil 7, which are interposed between the cathode 2 and the hearth 5 corresponding to the anode. Then, the arc discharge plasma flow 9 is generated from the pressure gradient type plasma gun 1 into the vacuum chamber 8. Reference numeral 10 denotes a discharge power supply for starting discharge between the cathode 2 and the hearth 5 and constantly maintaining discharge. Reference numeral 11 is a DC power source for applying a negative bias voltage to the arc discharge plasma flow 9, 12 is a discharge gas inlet for introducing a discharge gas into the pressure gradient plasma gun 1, and 13 is a reaction gas necessary for forming a film. A reaction gas inlet to be supplied, 14 is a magnet for focusing the arc discharge plasma flow 9 on the hearth 5, and 15 is 10 ⁻⁵ to 10 ⁻⁷ To inside the vacuum chamber 8.
An exhaust port 16 for exhausting to rr is a substrate on which a negative bias voltage from the DC power supply 11 is applied to the back surface to form a film on the front surface.

Further, the pressure gradient type plasma gun 1 is
There is no damage to the cathode due to the backflow of ions from the anode region, and the gas efficiency of the discharge gas for creating an arc discharge plasma flow is extremely high compared to the discharge type without an intermediate electrode, and a large current discharge is possible. Therefore, there is an advantage that the coating film can be easily increased in area.

When a film is formed on the substrate 16,
First, from the pressure gradient type plasma gun 1 to the discharge gas inlet 12
The arc discharge plasma flow 9 of the discharge gas supplied from the is concentrated on the hearth 5. Then, the arc discharge plasma flow 9
At the same time that the ions of the deposition material generated in the hearth 5 are radiated toward the negatively biased substrate 16 due to the concentration of the gas, the reaction gas supplied from the reaction gas inlet 13 passes through the arc discharge plasma flow 9 and is ionized. , Or in a neutralized state, is radiated toward the substrate 16 to form a compound film of the ions of the deposition material and the reaction gas on the substrate 16.

On the other hand, when a diamond-like coating is formed by using this arc discharge plasma flow generation source, the vapor deposition substance is not emitted from the hearth 5 and carbon atoms are contained in the vacuum chamber 8 from the reaction gas introduction port 13. By supplying the reaction gas, it was possible to decompose the reaction gas by the action of the arc discharge plasma flow 9 and form a diamond-like coating on the substrate.

[0011]

However, in the above-mentioned conventional apparatus, since the reaction gas is introduced into the vacuum chamber 8 from the reaction gas introduction port 13, it does not pass through the arc discharge plasma flow 9 and is ionized, or A large amount of non-neutralized reaction gas remains in the vacuum chamber 8, and the ionization or neutralization efficiency of the reaction gas was low.

Therefore, in order to form a diamond-like film at a desired film-forming rate, a large amount of reaction gas must be supplied from the reaction gas inlet 13 and exhausted by a large exhaust pump. It had led to an increase in size.

The present invention has been made in view of the above-mentioned problems, and the ionization efficiency or the neutralization efficiency of the reaction gas is increased, and the film formation rate is increased as compared with the conventional method without increasing the size of the apparatus. An object of the present invention is to provide a diamond-like film forming method and apparatus.

[0014]

According to the method for forming a diamond-like coating of the present invention, an arc discharge plasma flow is generated toward an anode arranged in a vacuum chamber, and carbon atoms are introduced from the anode into the arc discharge plasma flow. At the same time as supplying the reaction gas containing the above, a predetermined high frequency voltage is applied to the substrate arranged in the vacuum chamber to form a diamond-like film on the substrate.

The anode may be arranged so as to face the substrate, and the reaction gas may be supplied in a shower shape from the reaction gas introduction means provided in the anode toward the substrate.

Further, the self-bias generated on the substrate by applying the high frequency voltage may be set to -200 V or less with respect to the arc discharge plasma.

Next, in the diamond-like film forming apparatus of the present invention, a vacuum chamber, an arc discharge plasma flow generation source for generating an arc discharge plasma flow in the vacuum chamber, and an arc discharge plasma flow generation source are generated. An anode that forms an arc discharge with the arc discharge plasma flow generation source so that the arc discharge plasma flow is concentrated, and a reaction gas that is provided on the anode and that contains carbon atoms in the arc discharge plasma flow is supplied. On the substrate, a reactive gas introducing means for operating the substrate, a substrate arranged in the vicinity of the arc discharge plasma flow generated from the arc discharge plasma flow generation source, and a high frequency power source for applying a predetermined high frequency voltage to the substrate. It is characterized in that a diamond-like coating is formed on.

Further, the anode may be arranged opposite to the substrate and provided with a reaction gas introducing means for supplying the reaction gas in a shower shape toward the substrate.

Further, the self-bias generated on the substrate by applying a high frequency voltage from the high frequency power source may be set to -200 V or less with respect to the arc discharge plasma.

In addition, the arc discharge plasma flow generation source is interposed between the cathode and the cathode and the anode,
A pressure gradient type plasma gun comprising: a first intermediate electrode containing a ring-shaped permanent magnet; and a second intermediate electrode interposed between the first intermediate electrode and the anode and containing an air-core coil. Good.

[0021]

According to the method and apparatus for forming a diamond-like film of the present invention, the reaction gas containing carbon atoms supplied into the vacuum chamber always passes through the arc discharge plasma flow,
The ionization or neutralization efficiency of the reaction gas is increased.

Further, when the anode is arranged so as to face the substrate and the reaction gas is supplied in a shower shape from the reaction gas introduction means provided on the anode toward the substrate, it is decomposed by the action of the arc discharge plasma flow. The highly reactive ions and the reactive gas in the neutral active state are uniformly emitted to the substrate.

Further, when the self-bias generated on the substrate at the time of forming the diamond film is set to -200 V or less, a diamond-like film having high hardness can be formed on the substrate.

As an arc discharge plasma flow generation source, a cathode, a first intermediate electrode which is interposed between the cathode and the anode and has a ring-shaped permanent magnet built therein, and the first intermediate electrode and the anode are included. The second, which is interposed between and has a built-in air core coil
When a pressure gradient type plasma gun equipped with an intermediate electrode is used, the gas efficiency of the discharge gas for creating the arc discharge plasma flow is extremely high, and a large current discharge is possible, so that it is easy to form a large coating film. Area can be realized.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing an embodiment thereof. FIG. 1 is a schematic configuration diagram showing an apparatus for forming a diamond-like coating as an embodiment of the present invention. The same components as those in the conventional example (FIG. 5) described above are designated by the same reference numerals.

In the figure, 17 is arranged so as to be located in the vicinity of the arc discharge plasma flow 9 generated from the pressure gradient type plasma gun 1, and is made rotatable in the direction of the arrow at a speed of 10 to 20 rpm. A substrate holder, to which a substrate 16 is attached. Here, the reason why the substrate holder 17 is rotated is to reduce unevenness of the diamond-like coating formed on the substrate 16. In addition, the substrate 16 and the substrate holder 17
Was placed in the vicinity of the arc discharge plasma flow 9 without being placed in the arc discharge plasma flow 9 in order to prevent the substrate 16 and the substrate holder 17 from being heated to a high temperature by the arc discharge plasma flow 9. is there.

The substrate holder 17 has an oscillation frequency of 13.5.
A high frequency power source 18 having a maximum output of 500 W and having a frequency of 6 MHz is connected, and a high frequency voltage for generating a desired negative self-bias on the substrate 16 is applied to the substrate holder 17 by varying the output power.

Since the moving speed of the ions due to the electric field in the arc discharge plasma flow 9 is slower than that of the electrons due to the difference in mass, the electrons follow the fluctuation of the potential during the application of the high frequency voltage. , I take advantage of the fact that Ion cannot follow. Therefore, when a high frequency voltage is applied to the substrate 16, many electrons are emitted to the substrate 16 and
Negative self-bias will occur at 16.

Here, the high frequency power supply 18 is used as a power supply for keeping the surface of the substrate 16 at a negative potential from the arc discharge plasma flow 9 because the substrate 16 is insulated even if a bias voltage from a DC power supply is applied to the back surface. This is because negative charges are less likely to be generated on the substrate 16 when it is an object.

Reference numeral 19 denotes an arc discharge anode made of copper, and a refrigerant pipe 20 for cooling the anode 19 with water supplied from the outside of the vacuum chamber 8 is provided therein. This prevents the anode 19 from melting due to heating by the arc discharge plasma stream 9. A direct current voltage (about 80 V in this embodiment) is applied as a discharge power source 10 connected between the cathode 2 and the anode 19.

Further, the anode 19 is necessary when forming a film.
The required reaction gas (CH in this example _FourUse gas)
A reaction gas introducing means 21 for supplying the gas is provided.

As shown in FIG. 2, this reaction gas introducing means 21 has a plurality of emission holes 21a (17 in this embodiment) radially provided on the surface of the anode 19 facing the substrate 16. It is connected to the discharge hole 21a and is composed of a gas introducing portion 21b for introducing CH ₄ gas into the vacuum chamber 8. As a result, the CH ₄ gas supplied from the gas introduction part 21b is
CH ₄ gas is directly supplied into the arc discharge plasma flow while being ejected in a shower shape from 21a.

[0033] Therefore, since the supplying CH ₄ gas from the anode 19, CH ₄ gas supplied into the vacuum chamber 8, will be always passes through the arc plasma stream in, CH
₄ Gas ionization or neutralization efficiency can be increased. Further, since CH ₄ gas is supplied from the anode 19 toward the substrate 16 in a shower shape, the CH ₄ gas is decomposed by the action of the arc discharge plasma flow 9 and becomes a highly reactive ion or a neutral activated state of CH _4. The substrate 16 is uniformly irradiated with the gas.

Next, a method of forming a diamond-like film on the substrate 16 using the above apparatus will be described. Here, a Ni substrate was used as the substrate 16.

First, the inside of the vacuum chamber 8 is set to 10 ^-5 to 10 ^-7 Torr.
To the discharge gas inlet of the pressure gradient plasma gun 1.
Argon (Ar) gas was introduced from 12 at a supply partial pressure of 3.9 × 10 ⁻⁴ Torr, and about 80 V was applied to the discharge power source 10 to cause arc discharge to concentrate the arc discharge plasma flow 9 at the anode 19 and at the same time. CH ₄ gas is supplied into the vacuum chamber 8 from the reaction gas introduction means 21 provided in the anode 19, partial pressure 1.2 × 10 ⁻³ To
Introduce with rr. Then, a high-frequency voltage with an output of 11 W was applied from the high-frequency power source 18 to the substrate holder 17, and the self-bias generated on the substrate 16 was set to -200V.

As a result, the CH ₄ gas introduced from the reaction gas introducing means 21 is decomposed by the action of the arc discharge plasma flow 9 and becomes highly reactive ions or a neutral active state, so that it is deposited on the substrate 16. To reach.

The above steps are carried out for about 20 minutes to form a film on the substrate 16.
A 3000Å diamond-like coating layer was formed.

FIG. 3 shows a substrate 16 formed by using the above film forming method.
When a diamond-like coating is formed on the
2 shows the change in the film hardness with respect to the self-bias when the self-bias generated in the substrate 16 is changed by varying the output of. Here, the film hardness represents Vickers hardness, and was measured based on the standard of JIS G 0202. It should be noted that, instead of using the Ni substrate as the substrate 16, other substrates such as a Si substrate and a glass substrate were used, and the same results as in FIG. 3 were obtained. Also, the discharge gas inlet 12
The partial pressure of the Ar gas supplied from the reactor and the partial pressure of the CH ₄ gas supplied from the reaction gas introducing means 21 are 1.0 to 20.0 × 10
Even when other values of ^-4 Torr were set, the same results as in Fig. 3 were obtained.

As shown in FIG. 3, the hardness of the coating film formed on the substrate 16 is as low as about 400 Hv when the self-bias generated on the substrate 16 is 0 V, and the self-bias is 0 V to -200 V. The hardness of the coating increases as the bias voltage increases to a negative value, and the self-bias has a high value of about 2000 Hv at -200 V, and there is almost no change at self-bias of -300 V or less. It is a value around 2300 Hv.

Therefore, by setting the high-frequency voltage of the high-frequency power source 18 so that the self-bias generated on the substrate 16 becomes -200 V or less, a diamond-like coating having a high hardness of about 2000 Hv or more is formed on the substrate 16. I understand.

Next, in the above film forming method, the anode
When CH ₄ gas is supplied from the reaction gas introducing means 21 provided in 19 to form a diamond-like coating,
Similar to the conventional apparatus, when the CH ₄ gas is supplied from the reaction gas inlet 13 provided in the vacuum chamber 8 to form the diamond-like coating film, the relationship between the reaction gas supply amount and the film forming rate is shown in FIG. Shown in.

As shown in FIG. 4, the film formation rate increases with an increase in the reaction gas supply amount. For example, 150 Å / min
In the case of obtaining the film formation rate of, the reaction gas supply amount of about 1.18 Torr is required in the above method, whereas the reaction gas supply amount of about 0.97 Torr is necessary in the above method, and the above method is superior to the above method. It can be seen that the same film forming rate can be realized with a small reaction gas supply amount.

In the above embodiment, the Ar gas is supplied from the discharge gas introduction port 12 and the CH ₄ gas is supplied from the reaction gas introduction means 21 to form the diamond-like coating. Inert gas of discharge gas inlet 12
Other reactive gas containing carbon atoms, such as C ₂
H ₆ , C ₆ H ₆ , C ₃ H ₈ , CO, CO ₂ as reaction gas introduction means
You can supply from 21.

[0044]

As described above, according to the diamond-like film forming method and apparatus of the present invention, the reaction gas containing carbon atoms, which is supplied into the vacuum chamber, always passes through the arc discharge plasma flow, and the reaction gas Since the ionization efficiency or neutralization efficiency of is increased, without increasing the size of the device,
It becomes possible to form a diamond-like film having a desired film thickness in a shorter time than the conventional method.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a diamond-like film forming apparatus for carrying out the present invention.

FIG. 2 is a plan view of a reaction gas introduction unit in the apparatus of FIG. 1 embodiment.

FIG. 3 is a graph showing changes in coating hardness with respect to self-bias generated in a substrate when a diamond-like coating is formed on the substrate using the apparatus of FIG. 1 embodiment.

FIG. 4 is a graph showing the relationship between the reaction gas supply rate and the film formation rate in each case when a diamond-like coating is formed on a substrate using the apparatus of FIG. 1 and the apparatus of FIG. is there.

FIG. 5 is a configuration diagram showing an ion plating apparatus according to a conventional method.

[Explanation of symbols]

1 pressure gradient type plasma gun (arc discharge plasma flow generation source) 5 hearth (anode) 8 vacuum chamber 9 arc discharge plasma flow 10 discharge power supply 11 direct current power supply 12 discharge gas inlet 13 reaction gas inlet 16 substrate 18 high frequency power source 19 anode 20 Refrigerant tube 21 Discharge gas introduction means 21a Release hole 21b Gas introduction part

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[Procedure amendment]

[Submission date] February 18, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Further, the pressure gradient type plasma gun 1 is
There is no damage to the cathode due to the backflow of ions from the anode region, and the gas efficiency of the discharge gas for creating an arc discharge plasma flow is extremely high compared to the discharge type without an intermediate electrode, enabling large current discharge. Therefore, there is an advantage that the area of the coating can be easily increased.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction content]

As shown in FIG. 4, the film formation rate increases with an increase in the reaction gas supply amount. For example, 150 Å / min
In order to obtain a film formation rate of about 1.18 × 10 ⁻³ To
While the reaction gas supply amount of rr is required, the reaction gas supply amount of about 0.97 × 10 ⁻³ Torr is sufficient in the case of the above method, and the same reaction gas supply amount by the above method is smaller than that of the above method. It can be seen that the film formation speed can be realized.

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG.

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

[Figure 4]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Seiichi Kiyama 2-5-5 Keihan Hondori, Moriguchi City, Osaka Sanyo Electric Co., Ltd.

Claims (7)

[Claims] 1. An arc discharge plasma flow is generated toward an anode arranged in a vacuum chamber, and a reaction gas containing carbon atoms is supplied from the anode into the arc discharge plasma flow, and at the same time, is supplied into the vacuum chamber. A method for forming a diamond-like coating, which comprises applying a predetermined high-frequency voltage to a substrate placed on the substrate to form a diamond-like coating on the substrate. 2. The anode is arranged so as to face the substrate, and the reaction gas is supplied in a shower shape from the reaction gas introduction means provided in the anode toward the substrate. Diamond-like coating forming method. 3. The method for forming a diamond-like film according to claim 1, wherein the self-bias generated on the substrate by applying the high-frequency voltage is set to -200 V or less with respect to the arc discharge plasma. 4. A vacuum chamber, an arc discharge plasma flow generation source for generating an arc discharge plasma flow in the vacuum chamber, and an arc discharge plasma flow generated from the arc discharge plasma flow generation source for concentrating the arc discharge plasma flow. An anode for forming an arc discharge with an arc discharge plasma flow generation source; a reaction gas introduction means provided on the anode for supplying a reaction gas containing carbon atoms into the arc discharge plasma flow; and the arc discharge plasma. A substrate disposed in the vicinity of an arc discharge plasma flow generated from a flow generation source, and a high frequency power source for applying a predetermined high frequency voltage to the substrate, wherein a diamond-like coating is formed on the substrate. Diamond-like film forming device. 5. The diamond-like coating according to claim 4, wherein the anode is provided so as to face the substrate, and is provided with a reaction gas introducing means for supplying the reaction gas toward the substrate in a shower shape. Forming equipment. 6. The diamond-like structure according to claim 4, wherein the self-bias generated on the substrate by applying a high-frequency voltage from the high-frequency power source is set to −200 V or less with respect to the arc discharge plasma. Film forming equipment. 7. The arc discharge plasma flow generation source includes a cathode, a first intermediate electrode that is interposed between the cathode and the anode, and has an annular permanent magnet built therein, the first intermediate electrode and the anode. 7. The diamond-like film forming apparatus according to claim 4, which is a pressure gradient type plasma gun provided with a second intermediate electrode which is interposed between the second intermediate electrode and the second intermediate electrode.